WorldWideScience

Sample records for area p-i-n image

  1. A final report for Gallium arsenide P-I-N detectors for high-sensitivity imaging of thermal neutrons

    CERN Document Server

    Vernon, S M

    1999-01-01

    This SBIR Phase I developed neutron detectors made FR-om gallium arsenide (GaAs) p-type/ intrinsic/n-type (P-I-N) diodes grown by metalorganic chemical vapor deposition (MOCVD) onto semi-insulating (S1) bulk GaAs wafers. A layer of isotonically enriched boron-10 evaporated onto the FR-ont surface serves to convert incoming neutrons into lithium ions and a 1.47 MeV alpha particle which creates electron-hole pairs that are detected by the GaAs diode. Various thicknesses of ''intrinsic'' (I) undoped GaAs were tested, as was use of a back-surface field (BSF) formed FR-om a layer of Al sub x Ga sub 1 sub - sub x As. Schottky-barrier diodes formed FR-om the same structures without the p+ GaAs top layer were tested as a comparison. After mesa etching and application of contacts, devices were tested in visible light before application of the boron coating. Internal quantum efficiency (IQE) of the best diode near the GaAs bandedge is over 90%. The lowest dark current measured is 1 x 10 sup - sup 1 sup 2 amps at -1 V o...

  2. A final report for: Gallium arsenide P-I-N detectors for high-sensitivity imaging of thermal neutrons

    International Nuclear Information System (INIS)

    This SBIR Phase I developed neutron detectors made FR-om gallium arsenide (GaAs) p-type/ intrinsic/n-type (P-I-N) diodes grown by metalorganic chemical vapor deposition (MOCVD) onto semi-insulating (S1) bulk GaAs wafers. A layer of isotonically enriched boron-10 evaporated onto the FR-ont surface serves to convert incoming neutrons into lithium ions and a 1.47 MeV alpha particle which creates electron-hole pairs that are detected by the GaAs diode. Various thicknesses of ''intrinsic'' (I) undoped GaAs were tested, as was use of a back-surface field (BSF) formed FR-om a layer of AlxGa1-xAs. Schottky-barrier diodes formed FR-om the same structures without the p+ GaAs top layer were tested as a comparison. After mesa etching and application of contacts, devices were tested in visible light before application of the boron coating. Internal quantum efficiency (IQE) of the best diode near the GaAs bandedge is over 90%. The lowest dark current measured is 1 x 10-12 amps at -1 V on a 3mm x 3mm diode, or a density of 1.1 x 10-11 amps cm-2, with many of the diode structures tested having nearly similar results. The PIN diodes were significantly better than the Schottky barrier device, which had six orders of magnitude higher dark current. Diodes were characterized in terms of their current-mode response to 5.5 MeV alpha particles FR-om 241-Americium. These radiation-induced currents were as high as 9.78 x 10-7 A cm-1 on a PIN device with an AlxGa1-xAs BSF. Simple PIN diodes had currents as high as 2.44 x 10-7 A cm-2, with thicker undoped layers showing better sensitivity. Boron coatings were applied, and response to neutrons tested at University of Michigan by Dr. Doug McGregor. Devices with PIN and Schottky barrier designs showed neutron detection efficiencies as high as 2% on 5 (micro)m thick devices, with no need for external bias voltages. PIN diodes showed higher breakdown voltages and lower noise characteristics than did the Schottky barrier design. Uniformity of

  3. p-i-n CdTe multi-pixel detector for gamma-ray imaging fabricated by excimer laser processing

    International Nuclear Information System (INIS)

    A multi-pixel gamma-ray imaging detector unit, which has a high-energy resolution with room temperature operation, was fabricated using the diode-type CdTe detector. The diode structure was prepared by indium-doped n-type CdTe thin layer formed by excimer laser doping on one-side of high resistivity p-like single crystal CdTe wafer, and a gold electrode as a Shottkey electrode evaporated on the opposite side of the wafer. This diode-detectors showed good diode I-V characteristics with low leakage current. This CdTe detectors were pixelized in the 2mm x 2mm, and the 128 chips (32x4 chips) were mounted on the ceramic printed circuit boards at 3 mm interval with 1 mm gap. The printed circuit boards are directly connected the MCSA-EXI ASIC chip and 128 ch radiation spectrum analyzer systems. When using the Am-241 and the Co-57 as radioisotopes, the spectral response from all the pixels within 4,4 ke V of FWHM at 122 ke V peak of Co-57 for radiation performed at room temperature. The intensities of the peak from pixels were also uniform (Authors)

  4. Visualization and analysis of active dopant distribution in a p-i-n structured amorphous silicon solar cell using scanning nonlinear dielectric microscopy

    OpenAIRE

    Hirose, K.; N. Chinone; Cho, Y.

    2015-01-01

    Scanning nonlinear dielectric microscopy (SNDM) and super-higher-order (SHO-) SNDM were used for dopant profiling analysis of a cross-section of the p-i-n structure of an amorphous silicon solar cell. The p-i-n and zigzag structures of each layer boundary were visualized as carrier polarity and density images on 10-20 nm scale through a SNDM measurement. A capacitance-voltage curve was obtained at each pixel in the scan area through a SHO-SNDM measurement. The obtained SNDM and SHO-SNDM data ...

  5. Tunneling spectroscopy of a p-i-n diode interface

    Energy Technology Data Exchange (ETDEWEB)

    Loth, Sebastian; Wenderoth, Martin; Teichmann, Karen; Homoth, Jan; Loeser, Karolin; Ulbrich, Rainer G. [IV. Physikalisches Institut, Georg-August-Universitaet Goettingen (Germany); Malzer, Stefan; Doehler, Gottfried H. [Universitaet Erlangen-Nuernberg (Germany). Max-Planck-Research Group, Institute of Optics, Information, and Photonics

    2008-07-01

    The performance of modern semiconductor devices is largely influenced by the spatial distribution of dopants in the device's active region on the nanoscale. Since the late 80's Scanning Tunneling Microscopy (STM) was employed to study the local properties of p-n interfaces. Most studies were carried out on p-n superlattices allowing the investigation of intrinsic features accessible without applied bias across the diode. Here, a single GaAs p-i-n diode heterostructure is investigated with cross-sectional STM (X-STM) in a three-terminal configuration. External source and drain contacts control the electric field across the junction. Then, the diode's active region is mapped with atomic resolution. Local I(V)-spectroscopy (STS) directly resolves the band edge alignment from p to n for different diode bias conditions. The effect of the external electric field on the spatial and spectral images of individual dopant atoms in the active layer is discussed.

  6. A p-i-n junction diode based on locally doped carbon nanotube network

    OpenAIRE

    Xiaodong Liu; Changxin Chen; Liangming Wei; Nantao Hu; Chuanjuan Song; Chenghao Liao; Rong He; Xusheng Dong; Ying Wang; Qinran Liu; Yafei Zhang

    2016-01-01

    A p-i-n junction diode constructed by the locally doped network of single-walled carbon nanotubes (SWNTs) was investigated. In this diode, the two opposite ends of the SWNT-network channel were selectively doped by triethyloxonium hexachloroantimonate (OA) and polyethylenimine (PEI) to obtain the air-stable p- and n-type SWNTs respectively while the central area of the SWNT-network remained intrinsic state, resulting in the formation of a p-i-n junction with a strong built-in electronic field...

  7. Visualization and analysis of active dopant distribution in a p-i-n structured amorphous silicon solar cell using scanning nonlinear dielectric microscopy

    Directory of Open Access Journals (Sweden)

    K. Hirose

    2015-09-01

    Full Text Available Scanning nonlinear dielectric microscopy (SNDM and super-higher-order (SHO- SNDM were used for dopant profiling analysis of a cross-section of the p-i-n structure of an amorphous silicon solar cell. The p-i-n and zigzag structures of each layer boundary were visualized as carrier polarity and density images on 10-20 nm scale through a SNDM measurement. A capacitance-voltage curve was obtained at each pixel in the scan area through a SHO-SNDM measurement. The obtained SNDM and SHO-SNDM data suggest that the i-layer was not completely intrinsic, but was very-low-density p-type.

  8. A p-i-n junction diode based on locally doped carbon nanotube network

    Science.gov (United States)

    Liu, Xiaodong; Chen, Changxin; Wei, Liangming; Hu, Nantao; Song, Chuanjuan; Liao, Chenghao; He, Rong; Dong, Xusheng; Wang, Ying; Liu, Qinran; Zhang, Yafei

    2016-01-01

    A p-i-n junction diode constructed by the locally doped network of single-walled carbon nanotubes (SWNTs) was investigated. In this diode, the two opposite ends of the SWNT-network channel were selectively doped by triethyloxonium hexachloroantimonate (OA) and polyethylenimine (PEI) to obtain the air-stable p- and n-type SWNTs respectively while the central area of the SWNT-network remained intrinsic state, resulting in the formation of a p-i-n junction with a strong built-in electronic field in the SWNTs. The results showed that the forward current and the rectification ratio of the diode increased as the doping degree increased. The forward current of the device could also be increased by decreasing the channel length. A high-performance p-i-n junction diode with a high rectification ratio (~104), large forward current (~12.2 μA) and low reverse saturated current (~1.8 nA) was achieved with the OA and PEI doping time of 5 h and 18 h for a channel length of ~6 μm. PMID:26996610

  9. Continuous Holdup Measurements with Silicon P-I-N Photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Z.W.; Oberer, R.B.; Williams, J.A.; Smith, D.E.; Paulus, M.J.

    2002-05-01

    We report on the behavior of silicon P-I-N photodiodes used to perform holdup measurements on plumbing. These detectors differ from traditional scintillation detectors in that no high-voltage is required, no scintillator is used (gamma and X rays are converted directly by the diode), and they are considerably more compact. Although the small size of the diodes means they are not nearly as efficient as scintillation detectors, the diodes' size does mean that a detector module, including one or more diodes, pulse shaping electronics, analog-to-digital converter, embedded microprocessor, and digital interface can be realized in a package (excluding shielding) the size of a pocket calculator. This small size, coupled with only low-voltage power requirement, completely solid-state realization, and internal control functions allows these detectors to be strategically deployed on a permanent basis, thereby reducing or eliminating the need for manual holdup measurements. In this paper, we report on the measurement of gamma and X rays from {sup 235}U and {sup 238}U contained in steel pipe. We describe the features of the spectra, the electronics of the device and show how a network of them may be used to improve estimates of inventory in holdup.

  10. Strain tunable light emitting diodes with germanium P-I-N heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Lagally, Max G; Sanchez Perez, Jose Roberto

    2016-10-18

    Tunable p-i-n diodes comprising Ge heterojunction structures are provided. Also provided are methods for making and using the tunable p-i-n diodes. Tunability is provided by adjusting the tensile strain in the p-i-n heterojunction structure, which enables the diodes to emit radiation over a range of wavelengths.

  11. An Improved Physics-Based Formulation of the Microwave p-i-n Diode Impedance

    OpenAIRE

    Gatard, Emmanuel; Sommet, Raphaël; Bouysse, Philippe; Quéré, Raymond

    2007-01-01

    International audience An improved formulation of the frequency-dependent impedance for p-i-n diodes from physical and geometrical parameters is presented. This work is addressed to diode designers and allows them to evaluate quickly and accurately the diode impedance. It comes in parallel with existing SPICE p-i-n diode model [1] used in CAD software. Under forward bias conditions, important recombinations occur in the heavily doped end regions of thin p-i-n diodes that seriously affects ...

  12. P-I-N CdTe gamma-ray detectors by liquid phase epitaxy (LPE)

    International Nuclear Information System (INIS)

    A new device concept of CdTe gamma ray detectors has been demonstrated by using p+(HgCdTe)-n(CdTe)-n+(HgCdTe) diode structures. Both p+ and n+-type Hg/sub 0.25/Cd/sub 0.75/Te epilayers were grown by the liquid phase epitaxy (LPE) technique on semi-insulating CdTe sensor elements. The LPE-grown P-I-N structure offers potential advantages for p-n junction formation and ohmic contact over standard ion-implanted diodes or Schottky barrier devices. Detectors with active areas of 2 mm2 were fabricated. Resolutions of 10 keV were obtained for the 122 keV gamma peak of Co57 at room temperature

  13. InGaAs p-i-n Photodiodes for Microwave Applications

    OpenAIRE

    Malyshev, Sergei; Chizh, A.; Andrievski, Vatslav

    2004-01-01

    The experimental and theoretical study of the surface-illuminated InGaAs p-i-n photodiodes for such microwave applications as photonic microwave generation, optical control of microwave circuits and optoelectronic mixing is presented.

  14. Improved charge collection of the buried p-i-n a-Si:H radiation detectors

    International Nuclear Information System (INIS)

    Charge collection in hydrogenated amorphous silicon (a-Si:H) radiation detectors is improved for high LET particle detection by adding thin intrinsic layers to the usual p-i-n structure. This buried p-i-n structure enables us to apply higher bias and the electric field is enhanced. When irradiated by 5.8 MeV α particles, the 5.7 μm thick buried p-i-n detector with bias 300V gives a signal size of 60,000 electrons, compared to about 20,000 electrons with the simple p-i-n detectors. The improved charge collection in the new structure is discussed. The capability of tailoring the field profile by doping a-Si:H opens a way to some interesting device structures. 17 refs., 7 figs

  15. Parametric Optical Signal Processing in Silicon Waveguides with Reverse-biased p-i-n Junctions

    DEFF Research Database (Denmark)

    Peucheret, C.; Da Ros, Francesco; Vukovic, Dragana;

    2014-01-01

    The use of silicon-on-insulator waveguides with free carriers removal using a reverse-biased p-i-n junction for parametric optical signal processing is reviewed. High-efficiency wavelength conversion and phase-sensitive regeneration are reported.......The use of silicon-on-insulator waveguides with free carriers removal using a reverse-biased p-i-n junction for parametric optical signal processing is reviewed. High-efficiency wavelength conversion and phase-sensitive regeneration are reported....

  16. Fabrication and performance of p-i-n CdTe radiation detectors

    International Nuclear Information System (INIS)

    We report on the fabrication and performance of CdTe radiation detectors in a new p-i-n structure which helps to reduce the leakage current to a minimum level. Chlorine-doped single-crystal CdTe substrates having resistivity in the order of 109 Ω cm were used in this study. Iodine-doped n-type CdTe layers were grown homoepitaxially on one face of each crystals using the hydrogen plasma-radical-assisted metalorganic chemical vapor deposition technique at low substrate temperature of 150 deg. C. Indium electrode was evaporated on the n-CdTe side while a gold electrode on the opposite side acted as a p-type contact. Detectors thus fabricated exhibited low leakage current (below 0.4 nA/mm2 at 250 V applied reverse bias for the best one) and good performance at room temperature. Spectral response of the detectors showed improved energy resolution for Am-241, Co-57, and Cs-137 radioisotopes. Detectors were further tested with X-ray photons of different intensities for their potential application in imaging systems and promising responses were obtained

  17. Carbon nanotube intramolecular p-i-n junction diodes with symmetric and asymmetric contacts

    Science.gov (United States)

    Chen, Changxin; Liao, Chenghao; Wei, Liangming; Zhong, Hanqing; He, Rong; Liu, Qinran; Liu, Xiaodong; Lai, Yunfeng; Song, Chuanjuan; Jin, Tiening; Zhang, Yafei

    2016-01-01

    A p-i-n junction diode based on the selectively doped single-walled carbon nanotube (SWCNT) had been investigated, in which two opposite ends of individual SWCNT channel were doped into the p- and n-type SWCNT respectively while the middle segment of SWCNT was kept as the intrinsic. The symmetric and asymmetric contacts were used to fabricate the p-i-n junction diodes respectively and studied the effect of the contact on the device characteristics. It was shown that a low reverse saturation current of ~20 pA could be achieved by these both diodes. We found that the use of the asymmetric contact can effectively improve the performance of the p-i-n diode, with the rectification ratio enhanced from ~102 for the device with the Au/Au symmetric contact to >103 for the one with the Pd/Al asymmetric contact. The improvement of the device performance by the asymmetric-contact structure was attributed to the decrease of the effective Schottky-barrier height at the contacts under forward bias, increasing the forward current of the diode. The p-i-n diode with asymmetric contact also had a higher rectification ratio than its counterpart before doping the SWCNT channel, which is because that the p-i-n junction in the device decreased the reverse saturated current. PMID:26915400

  18. Growth of Shockley type stacking faults upon forward degradation in 4H-SiC p-i-n diodes

    Science.gov (United States)

    Tanaka, Atsushi; Matsuhata, Hirofumi; Kawabata, Naoyuki; Mori, Daisuke; Inoue, Kei; Ryo, Mina; Fujimoto, Takumi; Tawara, Takeshi; Miyazato, Masaki; Miyajima, Masaaki; Fukuda, Kenji; Ohtsuki, Akihiro; Kato, Tomohisa; Tsuchida, Hidekazu; Yonezawa, Yoshiyuki; Kimoto, Tsunenobu

    2016-03-01

    The growth of Shockley type stacking faults in p-i-n diodes fabricated on the C-face of 4H-SiC during forward current operation was investigated using Berg-Barrett X-ray topography and photoluminescence imaging. After forward current experiment, Shockley type stacking faults were generated from very short portions of basal plane dislocations lower than the conversion points to threading edge dislocations in the epitaxial layer. The growth behavior of Shockley type stacking faults was discussed. Growth of stacking faults in the substrates was not observed.

  19. Carbon nanotube intramolecular p-i-n junction diodes with symmetric and asymmetric contacts

    OpenAIRE

    Changxin Chen; Chenghao Liao; Liangming Wei; Hanqing Zhong; Rong He; Qinran Liu; Xiaodong Liu; Yunfeng Lai; Chuanjuan Song; Tiening Jin; Yafei Zhang

    2016-01-01

    A p-i-n junction diode based on the selectively doped single-walled carbon nanotube (SWCNT) had been investigated, in which two opposite ends of individual SWCNT channel were doped into the p- and n-type SWCNT respectively while the middle segment of SWCNT was kept as the intrinsic. The symmetric and asymmetric contacts were used to fabricate the p-i-n junction diodes respectively and studied the effect of the contact on the device characteristics. It was shown that a low reverse saturation c...

  20. Analysis of the p-i-n-structures Electrophysical Characteristics Influence on the Spectral Characteristics Sensitivity

    Directory of Open Access Journals (Sweden)

    V.N. Murashev

    2015-06-01

    Full Text Available In this paper the simulation of the silicon p-i-n-photodiodes spectral sensitivity characteristics was carried out. The analysis of the semiconductor material characteristics (the doping level, lifetime, surface recombination velocity, the construction and operation modes on the photosensitive structures characteristics in order to optimize them were investigated.

  1. Thermal ideality factor of hydrogenated amorphous silicon p-i-n solar cells

    NARCIS (Netherlands)

    Kind, R.; Van Swaaij, R.A.C.M.M.; Rubinelli, F.A.; Solntsev, S.; Zeman, M.

    2011-01-01

    The performance of hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells is limited, as they contain a relatively high concentration of defects. The dark current voltage (JV) characteristics at low forward voltages of these devices are dominated by recombination processes. The recombination rate

  2. Temperature dependence of electroluminescence from silicon p-i-n light-emitting diodes

    OpenAIRE

    Li, Cheng; Lai, Hongkai; Chen, Songyan; Suemasu, T.; Hasegawa, F

    2006-01-01

    The temperature dependence of electroluminescence from silicon p-i-n light-emitting diodes with a layer of beta-FeSi2 particles inserted in intrinsic silicon was investigated. Anomalous blueshift of the peak energy and enhanced electroluminescence intensity of the silicon band-edge emission were observed at temperatures from 50 to 200 K. The electroluminescence intensity was enhanced due to longer diffusion paths of the injected electrons at elevated temperature, as well as thermal escape ...

  3. Dimensional scaling effects on transport properties of ultrathin body p-i-n diodes

    OpenAIRE

    Rajasekharan, B.; van der Salm, C.; Hueting, R.J.E.; Hoang, Van T.; Schmitz, J.

    2008-01-01

    Device scaling has been a subject of research for both optoelectronics and electronics. In order to investigate the electronic properties of scaled devices we studied lateral p-i-n structures using thin silicon on insulator (SOI) or poly-Si layers of varying dimension. With the help of these structures we try to explain the size dependencies on electronic transport properties. Further, we also propose a new device concept called charge plasma diode.

  4. Improved designs for p-i-n OLEDs towards the minimal power loss of devices

    Science.gov (United States)

    Qin, Dashan

    2014-05-01

    Currently, the low yield, high power loss, and poor stability of organic light emitting diodes (OLEDs) panels are remaining as the obstacles to the fast growth of the OLED industry, especially for the lighting application. The p-i-n OLEDs have been widely recognized as the promising method to circumvent these bottleneck factors, due to the unique merit of the electrical doping to enable low power loss. In p-i-n OLEDs, the frequently used n-doped electron transport layers (n-ETL1) such as n-BCP, n-Alq3 possess markedly lower conductivities but better capabilities of injecting electrons into ETL such as BCP, Alq3, as compared to another class of n-doped ETLs (n-ETL2), e.g., n-NTCDA, n-PTCDA, n-C60. Thus, in order to minimize the electron loss, we provide the structure of uniting two n-doped layers, cathode/ n-ETL2/ n-ETL1/ ETL. In p-i-n OLEDs, the hole current injected from the single p-doped hole transport layer (p-HTL) into the neat HTL must be limited, because the higher conductivity p-HTL has the higher lying highest occupied molecular orbital (HOMO) level, leading to a larger hole transport energy barrier (φB) at the interface with the neat HTL. Therefore, in order to minimize the hole loss, we suggest the structure of uniting two p-HTLs, anode/ p-HTL2/ p-HTL1/ HTL. The p-HTL2 possesses high-lying HOMO level and thereby high conductivity, decreasing the ohmic loss in the hole conduction; the p-HTL1 features a low-lying HOMO level, reducing the φB.

  5. The Spectral Sensitivity Characteristics Simulation of the Silicon p-i-n-structure with High Resistance

    Directory of Open Access Journals (Sweden)

    S.A. Legotin

    2015-12-01

    Full Text Available In the paper a simulation program for photovoltaic parameters of semiconductor devices and results of their investigation are presented. The results of the program usage based on an example of calculating the influence of the high-resistance "well" thickness in the silicon p-i-n-diode spectral response are discussed. For the accuracy of the program estimation it was compared the theoretical spectral characteristics of a silicon PIN-diode 5 kOhm substrate with the experimental data.

  6. Density of states measurements in a p-i-n solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Crandall, R.S.; Wang, Q. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    The authors describe results of density of states (DOS) profiling in p-i-n solar-cell devices using drive-level capacitance (DLC) techniques. Near the p-i interface the defect density is high, decreasing rapidly into the interior, reaching low values in the central region of the cell, and rising rapidly again at the n-i interface. They show that the states in the central region are neutral dangling-bond defects, whereas those near the interfaces with the doped layers are charged dangling bonds.

  7. Improved spectrometric performance of CdTe radiation detectors in a p-i -n design

    OpenAIRE

    Niraula, Madan; Mochizuki, Daisuke; Aoki, Toru; Hatanaka, Yoshinori; Tomita, Yasuhiro; Nihashi, Tokuaki; ニラウラ, マダン

    1999-01-01

    CdTe radiation detectors were fabricated using a p-i-n design and a significant improvement in the spectral properties was obtained during room temperature operation. An iodine doped n-CdTe layer was grown on the Te faces of the (111) oriented high resistivity CdTe crystals at the low substrate temperature of 150°C. An aluminum electrode was evaporated on the n-CdTe side for the n-type contact, while a gold electrode on the opposite side acted as the p-type contact. Very low leakage currents,...

  8. Remarkable Franz-Keldysh Effect in Ge-on-Si p-i-n Diodes

    Institute of Scientific and Technical Information of China (English)

    LI Ya-Ming; HU Wei-Xuan; CHENG Bu-Wen; LIU Zhi; WANG Qi-Ming

    2012-01-01

    Ge-on-Si p-i-n diodes are fabricated by using two-step Ge film epitaxial technology on Si substrates.A remarkable Franz-Keldysh effect is observed in the wavelength range of 1620-1640nm with a largest Δα/α of 2.8 at 1640nm by optical responsivity measurement.The remarkable change of absorption coefficient in the considerable large wavelength range makes Ge-on-silicon a promising candidate for Si-based electro-absorption modulators. The initial design predicts a modulator of bandwidth ~50 GHz,and the extinction ratio > 7dB by the measured parameter.

  9. Flicker noise in high-speed p-i-n photodiodes

    CERN Document Server

    Rubiola, E; Yu, N; Maleki, L; Rubiola, Enrico; Salik, Ertan; Yu, Nan; Maleki, Lute

    2005-01-01

    The microwave signal at the output of a photodiode that detects a modulated optical beam contains the phase noise phi(t) and the amplitude noise alpha(t) of the detector. Beside the white noise, which is well understood, the spectral densities S_phi(f) and S_alpha(f) show flicker noise, proportional to 1/f. We report on the measurement of the phase and amplitude noise of high-speed p-i-n photodiodes. The main result is that the flicker coefficient of the samples is approximately 1E-12 rad^2/Hz (-120dB) for phase noise, and approximately 1E-12 Hz^-1 (-120dB) for amplitude noise. These values could be observed only after solving a number of experimental problems and in a protected environment. By contrast, in ordinary conditions insufficient EMI isolation, and also insufficient mechanical isolation, are responsible for additional noise to be taken in. This suggests that if package and EMC are revisited, applications can take the full benefit from the surprisingly low noise of the p-i-n photodiodes.

  10. Research on reverse recovery characteristics of SiGeC p-i-n diodes

    Institute of Scientific and Technical Information of China (English)

    Gao Yong; Liu Jing; Yang Yuan

    2008-01-01

    This paper analyses the reverse recovery characteristics and mechanism of SiGeC p-i-n diodes. Based on the integrated systems engineering (ISE) data, the critical physical models of SiGeC diodes are proposed. Based on heterojunction band gap engineering, the softness factor increases over six times, reverse recovery time is over 30% short and there is a 20% decrease in peak reverse recovery current for SiGeC diodes with 20% of germanium and 0.5% of carbon,compared to Si diodes. Those advantages of SiGeC p-i-n diodes are more obvious at high temperature. Compared to lifetime control, SiGeC technique is more suitable for improving diode properties and the tradeoff between reverse recovery time and forward voltage drop can be easily achieved in SiGeC diodes. Furthermore, the high thermal-stability of SiGeC diodes reduces the costs of further process steps and offers more freedoms to device design.

  11. Research on reverse recovery characteristics of SiGeC p-i-n diodes

    International Nuclear Information System (INIS)

    This paper analyses the reverse recovery characteristics and mechanism of SiGeC p-i-n diodes. Based on the integrated systems engineering (ISE) data, the critical physical models of SiGeC diodes are proposed. Based on hetero-junction band gap engineering, the softness factor increases over six times, reverse recovery time is over 30% short and there is a 20% decrease in peak reverse recovery current for SiGeC diodes with 20% of germanium and 0.5% of carbon, compared to Si diodes. Those advantages of SiGeC p-i-n diodes are more obvious at high temperature. Compared to lifetime control, SiGeC technique is more suitable for improving diode properties and the tradeoff between reverse recovery time and forward voltage drop can be easily achieved in SiGeC diodes. Furthermore, the high thermal-stability of SiGeC diodes reduces the costs of further process steps and offers more freedoms to device design. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  12. Planarization of High Aspect Ratio P-I-N Diode Pillar Arrays for Blanket Electrical Contacts

    Energy Technology Data Exchange (ETDEWEB)

    Voss, L F; Shao, Q; Reinhardt, C E; Graff, R T; Conway, A M; Nikolic, R J; Deo, N; Cheung, C L

    2009-03-05

    Two planarization techniques for high aspect ratio three dimensional pillar structured P-I-N diodes have been developed in order to enable a continuous coating of metal on the top of the structures. The first technique allows for coating of structures with topography through the use of a planarizing photoresist followed by RIE etch back to expose the tops of the pillar structure. The second technique also utilizes photoresist, but instead allows for planarization of a structure in which the pillars are filled and coated with a conformal coating by matching the etch rate of the photoresist to the underlying layers. These techniques enable deposition using either sputtering or electron beam evaporation of metal films to allow for electrical contact to the tops of the underlying pillar structure. These processes have potential applications for many devices comprised of 3-D high aspect ratio structures. Two separate processes have been developed in order to ensure a uniform surface for deposition of an electrode on the {sup 10}Boron filled P-I-N pillar structured diodes. Each uses S1518 photoresist in order to achieve a relatively uniform surface despite the non-uniformity of the underlying detector. Both processes allow for metallization of the final structure and provide good electrical continuity over a 3D pillar structure.

  13. High performance p-i-n CdTe and CdZnTe detectors

    CERN Document Server

    Khusainov, A K; Ilves, A G; Morozov, V F; Pustovoit, A K; Arlt, R D

    1999-01-01

    A breakthrough in the performance of p-i-n CdTe and CdZnTe detectors is reported. The detector stability has been significantly improved, allowing their use in precise gamma and XRF applications. Detectors with energy resolution close to Si and Ge were produced operating with only -30--35 deg. C cooling (by a Peltier cooler of 15x15x10 mm size and a consumed power less than 5 W). Presently detectors with volume of up to 300 mm sup 3 are available. In terms of photoelectric effect efficiency it corresponds to HPGe detectors with volumes of about 1.5 cm sup 3. The possibilities of further improvement of CdTe and CdZnTe detector characteristics are discussed in this paper.

  14. Monolithic integration of germanium-on-insulator p-i-n photodetector on silicon.

    Science.gov (United States)

    Nam, Ju Hyung; Afshinmanesh, Farzaneh; Nam, Donguk; Jung, Woo Shik; Kamins, Theodore I; Brongersma, Mark L; Saraswat, Krishna C

    2015-06-15

    A germanium-on-insulator (GOI) p-i-n photodetector, monolithically integrated on a silicon (Si) substrate, is demonstrated. GOI is formed by lateral-overgrowth (LAT-OVG) of Ge on silicon dioxide (SiO(2)) through windows etched in SiO(2) on Si. The photodetector shows excellent diode characteristics with high on/off ratio (6 × 10(4)), low dark current, and flat reverse current-voltage (I-V) characteristics. Enhanced light absorption up to 1550 nm is observed due to the residual biaxial tensile strain induced during the epitaxial growth of Ge caused by cooling after the deposition. This truly Si-compatible Ge photodetector using monolithic integration enables new opportunities for high-performance GOI based photonic devices on Si platform.

  15. High performance p-i-n CdTe and CdZnTe detectors

    Science.gov (United States)

    Khusainov, A. Kh; Dudin, A. L.; Ilves, A. G.; Morozov, V. F.; Pustovoit, A. K.; Arlt, R. D.

    1999-06-01

    A breakthrough in the performance of p-i-n CdTe and CdZnTe detectors is reported. The detector stability has been significantly improved, allowing their use in precise gamma and XRF applications. Detectors with energy resolution close to Si and Ge were produced operating with only -30--35°C cooling (by a Peltier cooler of 15×15×10 mm size and a consumed power less than 5 W). Presently detectors with volume of up to 300 mm 3 are available. In terms of photoelectric effect efficiency it corresponds to HPGe detectors with volumes of about 1.5 cm 3. The possibilities of further improvement of CdTe and CdZnTe detector characteristics are discussed in this paper.

  16. GeSn p-i-n photodetector for all telecommunication bands detection.

    Science.gov (United States)

    Su, Shaojian; Cheng, Buwen; Xue, Chunlai; Wang, Wei; Cao, Quan; Xue, Haiyun; Hu, Weixuan; Zhang, Guangze; Zuo, Yuhua; Wang, Qiming

    2011-03-28

    Using a 820 nm-thick high-quality Ge0.97Sn0.03 alloy film grown on Si(001) by molecular beam epitaxy, GeSn p-i-n photodectectors have been fabricated. The detectors have relatively high responsivities, such as 0.52 A/W, 0.23 A/W, and 0.12 A/W at 1310 nm, 1540 nm, and 1640 nm, respectively, under a 1 V reverse bias. With a broad detection spectrum (800-1800 nm) covering the whole telecommunication windows and compatibility with conventional complementary metal-oxide-semiconductors (CMOS) technology, the GeSn devices are attractive for applications in both optical communications and optical interconnects.

  17. Characterization of Power-to-Phase Conversion in High-Speed P-I-N Photodiodes

    CERN Document Server

    Taylor, J; Hati, A; Nelson, C; Quinlan, F; Joshi, A; Diddams, S

    2011-01-01

    Fluctuations of the optical power incident on a photodiode can be converted into phase fluctuations of the resulting electronic signal due to nonlinear saturation in the semiconductor. This impacts overall timing stability (phase noise) of microwave signals generated from a photodetected optical pulse train. In this paper, we describe and utilize techniques to characterize this conversion of amplitude noise to phase noise for several high-speed (>10 GHz) InGaAs P-I-N photodiodes operated at 900 nm. We focus on the impact of this effect on the photonic generation of low phase noise 10 GHz microwave signals and show that a combination of low laser amplitude noise, appropriate photodiode design, and optimum average photocurrent is required to achieve phase noise at or below -100 dBc/Hz at 1 Hz offset a 10 GHz carrier. In some photodiodes we find specific photocurrents where the power-to-phase conversion factor is observed to go to zero.

  18. GaN-based p-i-n X-ray detection

    International Nuclear Information System (INIS)

    GaN-based p-i-n X-ray detectors have been fabricated. We observed using SEM that the surface of a GaN sample has a large number of hexagonal defects. The SEM results show that GaN itself contains numerous screw dislocations that will be the flow channel of leakage current, which in turn increased the reverse-bias leakage current of detectors. We have observed a two-step increase in X-ray photocurrent, which is caused by two different detection mechanisms: photovoltaic and photoconductive, and the total photocurrent (Jp) to dark current (Jd) ratio is about 27.7 times and the net photocurrent is about 2.52 μA at 110 V reverse bias. As the X-ray accelerating voltage increases, the photocurrent has a sublinear trend. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Frequency dependence of junction capacitance of BPW34 and BPW41 p-i-n photodiodes

    Indian Academy of Sciences (India)

    Habibe Bayhan; Şadan Özden

    2007-04-01

    This article investigates the frequency dependence of small-signal capacitance of silicon BPW34 and BPW41 (Vishay) p-i-n photodiodes. We show that the capacitance-frequency characteristics of these photodiodes are well-described by the Schibli and Milnes model. The activation energy and the concentration of the dominant trap levels detected in BPW34 and BPW41 are 280{330 meV and 1.1 × 1012 - 1.2 × 1012 cm-3, respectively. According to the high-frequency - measurements, the impurity concentrations are determined to be about 5.3 × 1012 and 1.9 × 1013 cm-3 in BPW41 and BPW34, respectively using the method of / (-2) vs. .

  20. High-speed dual-wavelength demultiplexing and detection in a monolithic superlattice p-i-n waveguide detector array

    Science.gov (United States)

    Larsson, A.; Andrekson, P. A.; Andersson, P.; Eng, S. T.; Salzman, J.

    1986-01-01

    High-speed (1 Gbit/x) dual-wavelength demultiplexing and detection in a monolithic linear array of superlattice p-i-n photodetectors in a waveguide configuration is demonstrated. A crosstalk attenuation of 28 dB was achieved between two digital transmission channels with an interchannel wavelength spacing of 30 nm. The device performance is a result of an enhanced electroabsorption due to the quantum-confined Stark effect in the superlattice p-i-n diodes.

  1. High-speed dual-wavelength demultiplexing and detection in a monolithic superlattice p-i-n waveguide detector array

    OpenAIRE

    Larsson, A; Andrekson, P. A.; P. Andersson; Eng, S. T.; Salzman, J; Yariv, A.

    1986-01-01

    We demonstrate high-speed (1 Gbit/s) dual-wavelength demultiplexing and detection in a monolithic linear array of superlattice p-i-n photodetectors in a waveguide configuration. A crosstalk attenuation of 28 dB was achieved between two digital transmission channels with an interchannel wavelength spacing of 30 nm. The device performance is a result of an enhanced electroabsorption due to the quantum-confined Stark effect in the superlattice p-i-n diodes.

  2. Effects of contact electrode size on the characteristics of polycrystalline-Si p-i-n solar cells

    Institute of Scientific and Technical Information of China (English)

    M. H. Juang; H. Y. Huang; S. L. Jang

    2011-01-01

    The effects of contact electrode size on the photo-voltaic characteristics of polycrystalline-Si p-i-n solar cells have been studied,with respect to a unit-cell pitch size of 1 μm width.For the non-transparent A1 contact electrode with a contact width of 0.05-0.2 μm,the short-circuit current is obviously reduced with increasing contact width,due to a larger area of optical reflection by the electrode.On the other hand,even when using a transparent ITO (indium-tin-oxide) electrode,a larger width of contact electrode may also cause a smaller short-circuit current,due to a larger area of optical absorption by the electrode.However,for this ITO electrode,the contact electrode of 0.05 μm width causes a smaller short-circuit current than that of 0.1 μm width,primarily ascribed to a smaller area for collecting carrier and a larger contact resistance.As a result,while using the ITO contact electrode to enhance the conversion efficiency of the solar cell,a proper width of contact electrode should be employed to optimize the photo-voltaic characteristics.

  3. Integrated Amorphous Silicon p-i-n Temperature Sensor for CMOS Photonics

    Directory of Open Access Journals (Sweden)

    Sandro Rao

    2016-01-01

    Full Text Available Hydrogenated amorphous silicon (a-Si:H shows interesting optoelectronic and technological properties that make it suitable for the fabrication of passive and active micro-photonic devices, compatible moreover with standard microelectronic devices on a microchip. A temperature sensor based on a hydrogenated amorphous silicon p-i-n diode integrated in an optical waveguide for silicon photonics applications is presented here. The linear dependence of the voltage drop across the forward-biased diode on temperature, in a range from 30 °C up to 170 °C, has been used for thermal sensing. A high sensitivity of 11.9 mV/°C in the bias current range of 34–40 nA has been measured. The proposed device is particularly suitable for the continuous temperature monitoring of CMOS-compatible photonic integrated circuits, where the behavior of the on-chip active and passive devices are strongly dependent on their operating temperature.

  4. Dead layer on silicon p-i-n diode charged-particle detectors

    CERN Document Server

    Wall, B L; Beglarian, A; Bergmann, T; Bichsel, H C; Bodine, L I; Boyd, N M; Burritt, T H; Chaoui, Z; Corona, T J; Doeg, P J; Enomoto, S; Harms, F; Harper, G C; Howe, M A; Martin, E L; Parno, D S; Peterson, D A; Petzold, L; Renschler, P; Robertson, R G H; Schwarz, J; Steidl, M; Van Wechel, T D; VanDevender, B A; Wüstling, S; Wierman, K J; Wilkerson, J F

    2013-01-01

    Semiconductor detectors in general have a dead layer at their surfaces that is either a result of natural or induced passivation, or is formed during the process of making a contact. Charged particles passing through this region produce ionization that is incompletely collected and recorded, which leads to departures from the ideal in both energy deposition and resolution. The silicon \\textit{p-i-n} diode used in the KATRIN neutrino-mass experiment has such a dead layer. We have constructed a detailed Monte Carlo model for the passage of electrons from vacuum into a silicon detector, and compared the measured energy spectra to the predicted ones for a range of energies from 12 to 20 keV. The comparison provides experimental evidence that a substantial fraction of the ionization produced in the "dead" layer evidently escapes by diffusion, with 46% being collected in the depletion zone and the balance being neutralized at the contact or by bulk recombination. The most elementary model of a thinner dead layer fr...

  5. Dead layer on silicon p-i-n diode charged-particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Wall, B. L.; Amsbaugh, John F.; Beglarian, A.; Bergmann, T.; Bichsel, H. C.; Bodine, L. I.; Boyd, N. M.; Burritt, Tom H.; Chaoui, Z.; Corona, T. J.; Doe, Peter J.; Enomoto, S.; Harms, F.; Harper, Gregory; Howe, M. A.; Martin, E. L.; Parno, D. S.; Peterson, David; Petzold, Linda; Renschler, R.; Robertson, R. G. H.; Schwarz, J.; Steidl, M.; Van Wechel, T. D.; VanDevender, Brent A.; Wustling, S.; Wierman, K. J.; Wilkerson, J. F.

    2014-04-21

    Abstract Semiconductor detectors in general have a dead layer at their surfaces that is either a result of natural or induced passivation, or is formed during the process of making a contact. Charged particles passing through this region produce ionization that is incompletely collected and recorded, which leads to departures from the ideal in both energy deposition and resolution. The silicon p-i-n diode used in the KATRIN neutrinomass experiment has such a dead layer. We have constructed a detailed Monte Carlo model for the passage of electrons from vacuum into a silicon detector, and compared the measured energy spectra to the predicted ones for a range of energies from 12 to 20 keV. The comparison provides experimental evidence that a substantial fraction of the ionization produced in the "dead" layer evidently escapes by discussion, with 46% being collected in the depletion zone and the balance being neutralized at the contact or by bulk recombination. The most elementary model of a thinner dead layer from which no charge is collected is strongly disfavored.

  6. Tunable superlattice p-i-n photodetectors: Characteristics, theory, and applications

    Science.gov (United States)

    Larsson, Anders; Andrekson, Peter A.; Eng, Sverre T.; Yariv, Amnon

    1988-01-01

    Extended measurements and theory on the recently developed monolithic wavelength demultiplexer consisting of voltage-tunable superlattice p-i-n photodetectors in a waveguide configuration are discussed. It is shown that the device is able to demultiplex and detect two optical signals with a wavelength separation of 20 nm directly into different electrical channels at a data rate of 1 Gb/s and with a crosstalk attenuation varying between 20 and 28 dB, depending on the polarization. The minimum acceptable crosstalk attenuation at a data rate of 100 Mb/s is determined to be 10 dB. The feasibility of using the device as a polarization angle sensor for linearly polarized light is also demonstrated. A theory for the emission of photogenerated carriers out of the quantum wells is included, since this is potentially a speed limiting mechanism in these detectors. It is shown that a theory of thermally assisted tunneling by polar optical phonon interaction is able to predict emission times consistent with the observed temporal response.

  7. Si Radial p-i-n Junction Photovoltaic Arrays with Built-In Light Concentrators.

    Science.gov (United States)

    Yoo, Jinkyoung; Nguyen, Binh-Minh; Campbell, Ian H; Dayeh, Shadi A; Schuele, Paul; Evans, David; Picraux, S Tom

    2015-05-26

    High-performance photovoltaic (PV) devices require strong light absorption, low reflection and efficient photogenerated carrier collection for high quantum efficiency. Previous optical studies of vertical wires arrays have revealed that extremely efficient light absorption in the visible wavelengths is achievable. Photovoltaic studies have further advanced the wire approach by employing radial p-n junction architectures to achieve more efficient carrier collection. While radial p-n junction formation and optimized light absorption have independently been considered, PV efficiencies have further opportunities for enhancement by exploiting the radial p-n junction fabrication procedures to form arrays that simultaneously enhance both light absorption and carrier collection efficiency. Here we report a concept of morphology control to improve PV performance, light absorption and quantum efficiency of silicon radial p-i-n junction arrays. Surface energy minimization during vapor phase epitaxy is exploited to form match-head structures at the tips of the wires. The match-head structure acts as a built-in light concentrator and enhances optical absorptance and external quantum efficiencies by 30 to 40%, and PV efficiency under AM 1.5G illumination by 20% compared to cylindrical structures without match-heads. The design rules for these improvements with match-head arrays are systematically studied. This approach of process-enhanced control of three-dimensional Si morphologies provides a fab-compatible way to enhance the PV performance of Si radial p-n junction wire arrays. PMID:25961330

  8. The electrochemical capacitance-voltage characterization of InP based p-i-n structures

    Science.gov (United States)

    Wang, Li-wei; Lu, Yi-dan; Xu, Jin-tong; Li, Xiang-yang

    2013-09-01

    Electrochemical Capacitance-Voltage (EC-V) profiling is currently one of the most often used methods for majority carrier concentration depth profiling of semiconductors. The experiments of EC-V profiling on InP based structures were conducted by Wafer Profiler CVP21, and there are two problems in the experiments of InP based p-i-n structures : a)the experimental results of EC-V profiling of i layer were not in line with the theoretically data after the EC-V profiling of p layer, which can be measured within the error range; b) The measurements of etching depth were not very accurate. In this paper, we made comparative experiments on InP based n-i-n structures, and find out a method to deal with the first problem: firstly etch p layer before EC-V profiling, so we can gain a relatively accurate result of EC-V profiling of i layer. Besides, use back contacts instead of front contacts to do the EC-V profiling according to the instruction book of the Wafer Profiler CVP21. Then the author tried to infer the reason that results in the first problem theoretically. Meanwhile we can calibrate the etching depth through Profile-system and Scanning Probe Microscope (SPM). And there are two possible reasons which result in the second problem: the defects of the semiconductors and the electrolyte we used to etch the semiconductors.

  9. Dense nanoimprinted silicon nanowire arrays with passivated axial p-i-n junctions for photovoltaic applications

    Science.gov (United States)

    Zhang, Peng; Liu, Pei; Siontas, Stylianos; Zaslavsky, A.; Pacifici, D.; Ha, Jong-Yoon; Krylyuk, S.; Davydov, A. V.

    2015-03-01

    We report on the fabrication and photovoltaic characteristics of vertical arrays of silicon axial p-i-n junction nanowire (NW) solar cells grown by vapor-liquid-solid (VLS) epitaxy. NW surface passivation with silicon dioxide shell is shown to enhance carrier recombination time, open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF). The photovoltaic performance of passivated individual NW and NW arrays was compared under 532 nm laser illumination with power density of ˜10 W/cm2. Higher values of VOC and FF in the NW arrays are explained by enhanced light trapping. In order to verify the effect of NW density on light absorption and hence on the photovoltaic performance of NW arrays, dense Si NW arrays were fabricated using nanoimprint lithography to periodically arrange the gold seed particles prior to epitaxial growth. Compared to sparse NW arrays fabricated using VLS growth from randomly distributed gold seeds, the nanoimprinted NW array solar cells show a greatly increased peak external quantum efficiency of ˜8% and internal quantum efficiency of ˜90% in the visible spectral range. Three-dimensional finite-difference time-domain simulations of Si NW periodic arrays with varying pitch (P) confirm the importance of high NW density. Specifically, due to diffractive scattering and light trapping, absorption efficiency close to 100% in the 400-650 nm spectral range is calculated for a Si NW array with P = 250 nm, significantly outperforming a blanket Si film of the same thickness.

  10. Lead Halide Perovskite Photovoltaic as a Model p-i-n Diode.

    Science.gov (United States)

    Miyano, Kenjiro; Tripathi, Neeti; Yanagida, Masatoshi; Shirai, Yasuhiro

    2016-02-16

    The lead halide perovskite photovoltaic cells, especially the iodide compound CH3NH3PbI3 family, exhibited enormous progress in the energy conversion efficiency in the past few years. Although the first attempt to use the perovskite was as a sensitizer in a dye-sensitized solar cell, it has been recognized at the early stage of the development that the working of the perovskite photovoltaics is akin to that of the inorganic thin film solar cells. In fact, theoretically perovskite is always treated as an ordinary direct band gap semiconductor and hence the perovskite photovoltaics as a p-i-n diode. Despite this recognition, research effort along this line of thought is still in pieces and incomplete. Different measurements have been applied to different types of devices (different not only in the materials but also in the cell structures), making it difficult to have a coherent picture. To make the situation worse, the perovskite photovoltaics have been plagued by the irreproducible optoelectronic properties, most notably the sweep direction dependent current-voltage relationship, the hysteresis problem. Under such circumstances, it is naturally very difficult to analyze the data. Therefore, we set out to make hysteresis-free samples and apply time-tested models and numerical tools developed in the field of inorganic semiconductors. A series of electrical measurements have been performed on one type of CH3NH3PbI3 photovoltaic cells, in which a special attention was paid to ensure that their electronic reproducibility was better than the fitting error in the numerical analysis. The data can be quantitatively explained in terms of the established models of inorganic semiconductors: current/voltage relationship can be very well described by a two-diode model, while impedance spectroscopy revealed the presence of a thick intrinsic layer with the help of a numerical solver, SCAPS, developed for thin film solar cell analysis. These results point to that CH3NH3PbI3 is an

  11. Lead Halide Perovskite Photovoltaic as a Model p-i-n Diode.

    Science.gov (United States)

    Miyano, Kenjiro; Tripathi, Neeti; Yanagida, Masatoshi; Shirai, Yasuhiro

    2016-02-16

    The lead halide perovskite photovoltaic cells, especially the iodide compound CH3NH3PbI3 family, exhibited enormous progress in the energy conversion efficiency in the past few years. Although the first attempt to use the perovskite was as a sensitizer in a dye-sensitized solar cell, it has been recognized at the early stage of the development that the working of the perovskite photovoltaics is akin to that of the inorganic thin film solar cells. In fact, theoretically perovskite is always treated as an ordinary direct band gap semiconductor and hence the perovskite photovoltaics as a p-i-n diode. Despite this recognition, research effort along this line of thought is still in pieces and incomplete. Different measurements have been applied to different types of devices (different not only in the materials but also in the cell structures), making it difficult to have a coherent picture. To make the situation worse, the perovskite photovoltaics have been plagued by the irreproducible optoelectronic properties, most notably the sweep direction dependent current-voltage relationship, the hysteresis problem. Under such circumstances, it is naturally very difficult to analyze the data. Therefore, we set out to make hysteresis-free samples and apply time-tested models and numerical tools developed in the field of inorganic semiconductors. A series of electrical measurements have been performed on one type of CH3NH3PbI3 photovoltaic cells, in which a special attention was paid to ensure that their electronic reproducibility was better than the fitting error in the numerical analysis. The data can be quantitatively explained in terms of the established models of inorganic semiconductors: current/voltage relationship can be very well described by a two-diode model, while impedance spectroscopy revealed the presence of a thick intrinsic layer with the help of a numerical solver, SCAPS, developed for thin film solar cell analysis. These results point to that CH3NH3PbI3 is an

  12. Dense nanoimprinted silicon nanowire arrays with passivated axial p-i-n junctions for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peng; Liu, Pei; Siontas, Stylianos; Zaslavsky, A.; Pacifici, D. [Department of Physics and School of Engineering, Brown University, Providence, Rhode Island 02912 (United States); Ha, Jong-Yoon; Krylyuk, S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Davydov, A. V. [Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2015-03-28

    We report on the fabrication and photovoltaic characteristics of vertical arrays of silicon axial p-i-n junction nanowire (NW) solar cells grown by vapor-liquid-solid (VLS) epitaxy. NW surface passivation with silicon dioxide shell is shown to enhance carrier recombination time, open-circuit voltage (V{sub OC}), short-circuit current density (J{sub SC}), and fill factor (FF). The photovoltaic performance of passivated individual NW and NW arrays was compared under 532 nm laser illumination with power density of ∼10 W/cm{sup 2}. Higher values of V{sub OC} and FF in the NW arrays are explained by enhanced light trapping. In order to verify the effect of NW density on light absorption and hence on the photovoltaic performance of NW arrays, dense Si NW arrays were fabricated using nanoimprint lithography to periodically arrange the gold seed particles prior to epitaxial growth. Compared to sparse NW arrays fabricated using VLS growth from randomly distributed gold seeds, the nanoimprinted NW array solar cells show a greatly increased peak external quantum efficiency of ∼8% and internal quantum efficiency of ∼90% in the visible spectral range. Three-dimensional finite-difference time-domain simulations of Si NW periodic arrays with varying pitch (P) confirm the importance of high NW density. Specifically, due to diffractive scattering and light trapping, absorption efficiency close to 100% in the 400–650 nm spectral range is calculated for a Si NW array with P = 250 nm, significantly outperforming a blanket Si film of the same thickness.

  13. Phase regeneration of DPSK signals in a silicon waveguide with reverse-biased p-i-n junction

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Vukovic, Dragana; Gajda, Andrzej;

    2014-01-01

    Phase regeneration of differential phase-shift keying (DPSK) signals is demonstrated using a silicon waveguide as nonlinear medium for the first time. A p-i-n junction across the waveguide enables decreasing the nonlinear losses introduced by free-carrier absorption (FCA), thus allowing phase...

  14. Superlinear generation of exciton and related paramagnetism induced by forward current in a diamond p-i-n junction

    International Nuclear Information System (INIS)

    The concentration of excitons generated in a high-quality diamond p-i-n junction is investigated considering the forward current characteristics of the junction. As the forward current in the junction increases, the exciton concentration increases superlinearly, contrary to the linear increases of the electron and hole concentration. This tendency suggests a superlinear increase in emission intensity due to exciton recombination. The increase rate is more radical than quadratic, in accordance with the observed increase of the integrated intensity of free exciton emission. To estimate the concentration of triplet excitons generated in the p-i-n junction, observation of the paramagnetism due to the exciton spin moment is proposed. The magnetic susceptibility superlinearly increases with the increase in the forward current, unlike any other magnetic property of the device

  15. Large lateral photovoltaic effect in µc-SiOx:H/a-Si:H/c-Si p-i-n structure

    Science.gov (United States)

    Qiao, Shuang; Chen, Jianhui; Liu, Jihong; Zhang, Xinhui; Wang, Shufang; Fu, Guangsheng

    2016-03-01

    In this paper, we report on a large lateral photovoltaic effect (LPE) in a hydrogenated microcrystal silicon-oxygen (µc-SiOx:H)-based p-i-n structure. Compared with LPE in a hydrogenated amorphous silicon (a-Si:H)-based p-i-n structure, this structure showed an abnormal current-voltage (I-V) curve with a lower photoelectric conversion efficiency, but exhibited a much higher LPE with the highest position sensitivity of 64.3 mV/mm. We ascribe this to the enhancement of the lateral gradient of excess transmitted carriers induced by increasing both Schottky barrier and p-type layer body conductivity. Our results suggest that this µc-SiOx:H-based p-i-n structure may be a promising candidate for position-sensitive detectors (PSDs). Moreover, our results may also imply that solar cell devices with abnormal I-V curves (or low efficiency) could find their new applications in other aspects.

  16. Temperature and frequency dependence of negative differential capacitance in a planar GaN-based p-i-n photodetector

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); State Key Laboratories of Transducer Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Xu, Jintong; Li, Chao; Qiao, Hui; Zhang, Yan [State Key Laboratories of Transducer Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Li, Xiangyang, E-mail: lixy@mail.sitp.ac.cn [State Key Laboratories of Transducer Technology, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

    2013-12-25

    Highlights: •Planar GaN-based p-i-n photodetector was prepared by ion implantation. •A novel negative differential capacitance (NDC) effect is observed in the photodetector. •The NDC effect is due to the carrier confinement of the deep level centers formed by ion implantation. -- Abstract: In this work, back-illuminated planar GaN-based p-i-n photodetectors were fabricated by Si implantation into GaN-based p-i-n structure grown by metal–organic chemical vapor deposition (MOCVD). The dark current density of the photodetector is 1.03 nA/cm{sup 2} under zero bias. The unbiased responsivity is 0.122 A/W at 360 nm, corresponding to an external quantum efficiency of 42%. Temperature and frequency dependence of capacitance versus voltage characteristics of the photodetectors are also investigated respectively. A novel negative differential capacitance (NDC) effect observed in the photodetector at room temperature under the frequency of 120 kHz or at low temperature under relative high frequency (such as 200 kHz). The NDC effect becomes much more obvious with the temperature or frequency decreased. This novel phenomenon is mainly due to the carrier confinement of the deep level centers in the detector, which mainly include lattice defects formed by high dose ion implantation and subsequent annealing.

  17. Metamorphic In0.53Ga0.47As p-I-n photodetector grown on GaAs substrates by low-pressure MOCVD

    Institute of Scientific and Technical Information of China (English)

    Qi wang; Jihe Lü; Deping Xiong; Jing Zhou; Hui Huang; Ang Miao; Shiwei Cai; Yongqing Huang; Xiaomin Ren

    2007-01-01

    Top-illuminated metamorphic In0.53Ga0.47As p-i-n photodetectors are grown on the ultrathin lowtemperature InP buffered GaAs substrates. Photodetectors with the 300-nm-thick In0.53Ga0.47As absorption layer show a typical responsivity of 0.12 A/W to 1.55-μm optical radiation, corresponding to an external quantum efficiency of 9.6%. Photodetectors with the active area of 50 × 50 (μm) exhibit the -3 dB bandwidth up to 6 GHz. These results are very encouraging for the application of this metamorphic technology to opto-electronic integrated circuit (OEIC) devices.

  18. Optimization of p-GaN/InGaN/n-GaN Double Heterojunction p-i-n Solar Cell for High Efficiency: Simulation Approach

    Directory of Open Access Journals (Sweden)

    Aniruddha Singh Kushwaha

    2014-01-01

    Full Text Available We have conducted numerical simulation of p-GaN/In0.12Ga0.88N/n-GaN, p-i-n double heterojunction solar cell. The doping density, individual layer thickness, and contact pattern of the device are investigated under solar irradiance of AM1.5 for optimized performance of solar cell. The optimized solar cell characteristic parameters for cell area of 1  × 1 mm2 are open circuit voltage of 2.26 V, short circuit current density of 3.31 mA/cm2, fill factor of 84.6%, and efficiency of 6.43% with interdigitated grid pattern.

  19. Amorphous silicon p-i-n diodes, deposited by the VHF-GD process: new experimental results

    OpenAIRE

    P. Chabloz; Keppner, Herbert; Fischer, Diego; Link, D.; Shah, Arvind

    2008-01-01

    a-Si:H i-layers were deposited at different substrate temperatures and plasma excitation frequencies, while the other deposition parameters were kept constant. These layers were characterised by measuring the intrinsic mechanical stress and the defect density. At deposition temperatures of 200 to 250°C low stress and a low defect density were obtained for excitation frequencies between 60 and 70 MHz. A second part shows the spectral response of thick p-i-n diodes for different reverse bias vo...

  20. Analysis of Deep Level Defects in GaN p-i-n Diodes after Beta Particle Irradiation

    Directory of Open Access Journals (Sweden)

    Sofiane Belahsene

    2015-12-01

    Full Text Available The effect of beta particle irradiation (electron energy 0.54 MeV on the electrical characteristics of GaN p-i-n diodes is investigated by current-voltage (I-V, capacitance-voltage (C-V and deep-level transient spectroscopy (DLTS measurements. The experimental studies show that, for the as-grown samples, three electron traps are found with activation energies ranging from 0.06 to 0.81 eV and concentrations ranging from 1.2 × 1014 to 3.6 × 1015 cm−3, together with one hole trap with energy depth of 0.83 eV and concentration of 8 × 1014 cm−3. It has been found that the irradiation has no effect on these intrinsic defects. The irradiation affected only a shallow donor level close to Ec [0.06 eV-0.18 eV] on the p-side of the p-i-n junction.

  1. Signal amplification and leakage current suppression in amorphous silicon p-i-n diodes by field profile tailoring

    International Nuclear Information System (INIS)

    The performance of amorphous silicon p-i-n diodes as radiation detectors in terms of signal amplitude can be greatly improved when there is a built-in signal gain mechanism. The authors describe an avalanche gain mechanism which is achieved by introducing stacked intrinsic, p-type, and n-type layers into the diode structure. They replaced the intrinsic layer of the conventional p-i-n diode with i1-p-i2-n-i3 multilayers. The i2 layer (typically 1 ∼ 3 microm) achieves an electric field > 106 V/cm, while maintaining the p-i interfaces to the metallic contact at electric fields 4 V/cm, when the diode is fully depleted. For use in photo-diode applications the whole structure is less than 10 microm thick. Avalanche gains of 10 ∼ 50 can be obtained when the diode is biased to ∼ 500 V. Also, dividing the electrodes to strips of 2 microm width and 20 microm pitch reduced the leakage current up to an order of magnitude, and increased light transmission without creating inactive regions

  2. Investigation of the polysilicon p-i-n diode and diode string as a process compatible and portable ESD protection device

    Institute of Scientific and Technical Information of China (English)

    Jiang Yibo; Du Huan; Han Zhengsheng

    2012-01-01

    The polysilicon p-i-n diode displays noticeable process compatibility and portability in advanced technologies as an electrostatic-discharge (ESD) protection device.This paper presents the reverse breakdown,current leakage and capacitance characteristics of fabricated polysilieon p-i-n diodes.To evaluate the ESD robustness,the forward and reverse TLP Ⅰ-Ⅴ characteristics were measured.The polysilicon p-i-n diode string was also investigated to further reduce capacitance and fulfill the requirements of tunable cut-in or reverse breakdown voltage.Finally,to explain the effects of the device parameters,we analyze and discuss the inherent properties of polysilicon p-i-n diodes.

  3. Analytical and equivalent-circuit models based on numerical solutions for amorphous silicon p/i/n solar cells

    Science.gov (United States)

    Misiakos, K.; Lindholm, F. A.

    The authors present contact-to-contact computer solutions of the a-Si:H p/i/n solar cell and uses these to obtain the approximations and insight needed for the development of analytical models. The numerical results allow study of many aspects of internal variables as functions of position, terminal voltage, and phonon flux density. Based on the numerical results, analytical and equivalent-circuit models are proposed which support each other and explain the physical origin of interdependencies among such variables as quantum efficiency, electric field and recombination rate profiles, and their relation to current-voltage characteristics. The concept of the limiting carrier is mathematically treated by separating the current into photocollected and back-injection components. The limiting carrier is the carrier with the least photocollected current.

  4. Investigation of p-i-n solar cell efficiency enhancement by use of MQW structures in the i-region

    Energy Technology Data Exchange (ETDEWEB)

    Ashenford, D.E.; Dweydari, A.W.; Sands, D.; Scott, C.G.; Yousaf, M. [Department of Applied Physics, University of Hull, Hull (United Kingdom); Aperathitis, E.; Hatzopoulos, Z.; Panayotatos, P. [Institute of Electronic Structure, Forth, Heraklion (Greece)

    1996-02-15

    The effects of CdTe quantum wells in CdMnTe Schottky junctions and p-i-n structures have been explored with a view to determining the improvements in photovoltaic energy conversion efficiency which might be achieved in such devices. Spectral response measurements have demonstrated (1) that the presence of the wells successfully extends the range of absorbed photons to lower energies and (2) that, under normal ambient temperature conditions, the photostimulated carriers have a high probability of escaping from the wells, thereby contributing to the photogenerated current. Measurements at lower temperatures have indicated a reduced quantum efficiency, consistent with theoretical prediction assuming carrier escape from the wells to be a predominantly thermally activated process

  5. The effect of embedded nanopillars on the built-in electric field of amorphous silicon p-i-n devices

    Science.gov (United States)

    Kirkpatrick, T.; Simmons, C. B.; Akey, A. J.; Tabet, N.; Buonassisi, T.

    2016-05-01

    In this work, we report on the experimental modification of the built-in electric field of a-Si:H p-i-n junctions, resulting from Ag nanopillars embedded within the intrinsic layer (i-layer). Increased open-circuit voltages, from J-V traces, and reduced charge transit-times, from time-of-flight (ToF) measurements, indicate that the built-in electric field within the i-layer is increased with respect to unstructured reference samples. Decreased short-circuit current density values coupled with competing diode J-V characteristics, however, indicate that the charge collection from the i-layer is significantly decreased for the nanopillar samples. Theoretical and functional analysis of the ToF data reaffirms both reduced charge-transit times and decreased charge collection, and is able to quantitatively confirm the enhanced built-in electric field of the nanopillar samples.

  6. Improvement of High Temperature Characteristics for SiGeC p-i-n Diodes with Carbon Incorporation

    Institute of Scientific and Technical Information of China (English)

    GAO Yong; LIU Jing; YANG Yuan

    2008-01-01

    Temperature-dependent characteristics of SiGeC p-i-n diodes are analysed and discussed. Based on the ISE data, the temperature-dependent physical models applicable for SiGeC/Si diodes are presented. Due to the addition of carbon into the SiGe system, the thermal stability of SiGeC diodes are improved remarkably. Compared to SiGe diodes, the reverse leakage current of SiGeC diodes is decreased by 97.1% at 400 K and its threshold voltage shift is reduced over 65.3% with an increasing temperature from 300 K to 400 K. Furthermore, the fast and soft reverse recovery characteristics are also obtained at 400 K for SiGeC diodes. As a result, the most remarkable feature of SiGeC diodes is the better high-temperature characteristics and this can be applied to high temperature up to 400 K.

  7. Resonant metallic nanostructure for enhanced two-photon absorption in a thin GaAs p-i-n diode

    International Nuclear Information System (INIS)

    Degenerate two-photon absorption (TPA) is investigated in a 186 nm thick gallium arsenide (GaAs) p-i-n diode embedded in a resonant metallic nanostructure. The full device consists in the GaAs layer, a gold subwavelength grating on the illuminated side, and a gold mirror on the opposite side. For TM-polarized light, the structure exhibits a resonance close to 1.47 μm, with a confined electric field in the intrinsic region, far from the metallic interfaces. A 109 times increase in photocurrent compared to a non-resonant device is obtained experimentally, while numerical simulations suggest that both gain in TPA-photocurrent and angular dependence can be further improved. For optimized grating parameters, a maximum gain of 241 is demonstrated numerically and over incidence angle range of (−30°; +30°).

  8. Open-circuit voltage analysis of p-i-n type amorphous silicon solar cells deposited at low temperature

    Institute of Scientific and Technical Information of China (English)

    Ni Jian; Zhang Jian-Jun; Cao Yu; Wang Xian-Bao; Li Chao; Chen Xin-Liang; Geng Xin-Hua; Zhao Ying

    2011-01-01

    This paper identifies the contributions of p-a-SiC:H layers and i-a-Si:H layers to the open circuit voltage of p-i-n type a-Si:H solar cells deposited at a low temperature of 125 ℃.We find that poor quality p-a-SiC:H films under regular conditions lead to a restriction of open circuit voltage although the band gap of the i-layer varies widely.A significant improvement in open circuit voltage has been obtained by using high quality p-a-SiC:H films optimized at the "low-power regime" under low silane flow rates and high hydrogen dilution conditions.

  9. Effects of Be acceptors on the spin polarization of carriers in p-i-n resonant tunneling diodes

    International Nuclear Information System (INIS)

    In this paper, we have investigated the effect of Be acceptors on the electroluminescence and the spin polarization in GaAs/AlAs p-i-n resonant tunneling diodes. The quantum well emission comprise two main lines separated by ∼20 meV attributed to excitonic and Be-related transitions, which intensities show remarkably abrupt variations at critical voltages, particularly at the electron resonant peak where it shows a high-frequency bistability. The circular-polarization degree of the quantum-well electroluminescence also shows strong and abrupt variations at the critical bias voltages and it attains relatively large values (of ∼−75% at 15 T). These effects may be explored to design novel devices for spintronic applications such as a high-frequency spin-oscillators

  10. Effects of Be acceptors on the spin polarization of carriers in p-i-n resonant tunneling diodes

    Science.gov (United States)

    Awan, I. T.; Galeti, H. V. A.; Galvão Gobato, Y.; Brasil, M. J. S. P.; Taylor, D.; Henini, M.

    2014-08-01

    In this paper, we have investigated the effect of Be acceptors on the electroluminescence and the spin polarization in GaAs/AlAs p-i-n resonant tunneling diodes. The quantum well emission comprise two main lines separated by ˜20 meV attributed to excitonic and Be-related transitions, which intensities show remarkably abrupt variations at critical voltages, particularly at the electron resonant peak where it shows a high-frequency bistability. The circular-polarization degree of the quantum-well electroluminescence also shows strong and abrupt variations at the critical bias voltages and it attains relatively large values (of ˜-75% at 15 T). These effects may be explored to design novel devices for spintronic applications such as a high-frequency spin-oscillators.

  11. High-Efficiency P-I-N Microcrystalline and Micromorph Thin Film Silicon Solar Cells Deposited on LPCVD Zno Coated Glass Substrates

    OpenAIRE

    Bailat, Julien; Dominé, Didier; Schlüchter, R.; Steinhauser, Jérôme; Faÿ, Sylvie; F Freitas; Bucher, C.; Feitknecht, Luc; Niquille, Xavier; Tscharner, T.; Shah, Arvind; Ballif, Christophe

    2008-01-01

    The authors report on the fabrication of microcrystalline silicon p-i-n solar cells with efficiencies close to 10%, using glass coated with zinc oxide (ZnO) deposited by low pressure chemical vapor deposition (LPCVD). LPCVD front contacts were optimized for p-i-n microcrystalline silicon solar cells by decreasing the free carrier absorption of the layers and increasing the surface roughness. These modifications resulted in an increased current density of the solar cell but also in significant...

  12. Highly transparent front electrodes with metal fingers for p-i-n thin-film silicon solar cells

    Directory of Open Access Journals (Sweden)

    Moulin Etienne

    2015-01-01

    Full Text Available The optical and electrical properties of transparent conductive oxides (TCOs, traditionally used in thin-film silicon (TF-Si solar cells as front-electrode materials, are interlinked, such that an increase in TCO transparency is generally achieved at the cost of reduced lateral conductance. Combining a highly transparent TCO front electrode of moderate conductance with metal fingers to support charge collection is a well-established technique in wafer-based technologies or for TF-Si solar cells in the substrate (n-i-p configuration. Here, we extend this concept to TF-Si solar cells in the superstrate (p-i-n configuration. The metal fingers are used in conjunction with a millimeter-scale textured foil, attached to the glass superstrate, which provides an antireflective and retroreflective effect; the latter effect mitigates the shadowing losses induced by the metal fingers. As a result, a substantial increase in power conversion efficiency, from 8.7% to 9.1%, is achieved for 1-μm-thick microcrystalline silicon solar cells deposited on a highly transparent thermally treated aluminum-doped zinc oxide layer combined with silver fingers, compared to cells deposited on a state-of-the-art zinc oxide layer.

  13. Optimizing photon-pair generation electronically using a p-i-n diode incorporated in a silicon microring resonator

    Energy Technology Data Exchange (ETDEWEB)

    Savanier, Marc, E-mail: msavanier@eng.ucsd.edu; Kumar, Ranjeet; Mookherjea, Shayan, E-mail: smookherjea@eng.ucsd.edu [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    2015-09-28

    Silicon photonic microchips may be useful for compact, inexpensive, room-temperature optically pumped photon-pair sources, which unlike conventional photon-pair generators based on crystals or optical fibers, can be manufactured using CMOS-compatible processes on silicon wafers. It has been shown that photon pairs can be created in simple structures such as microring resonators at a rate of a few hundred kilohertz using less than a milliwatt of optical pump power, based on the process of spontaneous four-wave mixing. To create a practical photon-pair source, however, also requires some way of monitoring the device and aligning the pump wavelength when the temperature varies, since silicon resonators are highly sensitive to temperature. In fact, monitoring photodiodes are standard components in classical laser diodes, but the incorporation of germanium or InGaAs photodiodes would raise the cost and fabrication complexity. Here, we present a simple and effective all-electronic technique for finding the optimum operating point for the microring used to generate photon pairs, based on measuring the reverse-biased current in a silicon p-i-n junction diode fabricated across the waveguide that constitutes the silicon microring. We show that by monitoring the current, and using it to tune the pump laser wavelength, the photon-pair generation properties of the microring can be preserved over a temperature range of more than 30 °C.

  14. Effect of high dose γ-ray irradiation on GaAs p-i-n photodetectors

    Energy Technology Data Exchange (ETDEWEB)

    Dixit, V.K., E-mail: dixit@rrcat.gov.in; Khamari, Shailesh K.; Manwani, Sapna; Porwal, S.; Alexander, K.; Sharma, T.K.; Kher, S.; Oak, S.M.

    2015-06-11

    Metal organic vapor phase epitaxy grown GaAs p-i-n photodetector devices are fabricated and tested for the assessment of practical usage of the detector after the exposure to high radiation doses of γ-ray. Increased values of saturation current, ideality factor and leakage current after 360 kGy γ-ray irradiation confirm a substantial increase in the number of generation–recombination centers. It is further observed that the leakage current density, current per unit volume (J{sub v}), increases linearly with the radiation fluence (Φ). The slope (α=ΔJ{sub v}/ΔΦ) of the leakage current density versus γ-ray radiation fluences curve is two order less (4–5×10{sup −l9} A/cm) for GaAs compared to Si (4–6×10{sup −l7} A/cm). The lower value of α (radiation damage constant) confirms that GaAs is radiation harder than Si. Subsequently, it is also observed that the photo response of 360 kGy γ-ray irradiated GaAs device is reduced by ~50% due to the reduction of quantum efficiency by the radiation induced generation–recombination centers. The functionality of the irradiated sensor is verified by comparing the response of the pristine and irradiated detectors to the photoluminescence of semiconductor quantum well structures.

  15. Comprehensive physics-based compact model for fast p-i-n diode using MATLAB and Simulink

    Science.gov (United States)

    Xue, Peng; Fu, Guicui; Zhang, Dong

    2016-07-01

    In this study, a physics-based model for the fast p-i-n diode is proposed. The model is based on the 1-D Fourier-based solution of ambipolar diffusion equation (ADE) implemented in MATLAB and Simulink. The physical characteristics of fast diode design concepts such as local lifetime control (LLC), emitter control (EMCON) and deep field stop are taken into account. Based on these fast diode design concepts, the ADE is solved for all injection levels instead of high-level injection only as usually done. The variation of high-level lifetime due to local lifetime control is also included in the solution. With the deep field stop layer taken into consideration, the depletion behavior in the N-base during reverse recovery is redescribed. Some physical effects such as avalanche generation and carrier recombination in the depletion region are also taken into account. To be self contained, a parameter extraction method is proposed to extract all the parameters of the model. In the end, the static and reverse recovery experiments for a commercial EMCON diode and a LLC diode are used to validate the proposed model. The simulation results are compared with experiment results and good agreement is obtained.

  16. Effect of high dose γ-ray irradiation on GaAs p-i-n photodetectors

    Science.gov (United States)

    Dixit, V. K.; Khamari, Shailesh K.; Manwani, Sapna; Porwal, S.; Alexander, K.; Sharma, T. K.; Kher, S.; Oak, S. M.

    2015-06-01

    Metal organic vapor phase epitaxy grown GaAs p-i-n photodetector devices are fabricated and tested for the assessment of practical usage of the detector after the exposure to high radiation doses of γ-ray. Increased values of saturation current, ideality factor and leakage current after 360 kGy γ-ray irradiation confirm a substantial increase in the number of generation-recombination centers. It is further observed that the leakage current density, current per unit volume (Jv), increases linearly with the radiation fluence (Φ). The slope (α=ΔJv/ΔΦ) of the leakage current density versus γ-ray radiation fluences curve is two order less (4-5×10-l9 A/cm) for GaAs compared to Si (4-6×10-l7 A/cm). The lower value of α (radiation damage constant) confirms that GaAs is radiation harder than Si. Subsequently, it is also observed that the photo response of 360 kGy γ-ray irradiated GaAs device is reduced by ~50% due to the reduction of quantum efficiency by the radiation induced generation-recombination centers. The functionality of the irradiated sensor is verified by comparing the response of the pristine and irradiated detectors to the photoluminescence of semiconductor quantum well structures.

  17. Built-in voltage of organic bulk heterojuction p-i-n solar cells measured by electroabsorption spectroscopy

    Directory of Open Access Journals (Sweden)

    E. Siebert-Henze

    2014-04-01

    Full Text Available We investigate the influence of the built-in voltage on the performance of organic bulk heterojuction solar cells that are based on a p-i-n structure. Electrical doping in the hole and the electron transport layer allows to tune their work function and hence to adjust the built-in voltage: Changing the doping concentration from 0.5 to 32 wt% induces a shift of the work function towards the transport levels and increases the built-in voltage. To determine the built-in voltage, we use electroabsorption spectroscopy which is based on an evaluation of the spectra caused by a change in absorption due to an electric field (Stark effect. For a model system with a bulk heterojunction of BF-DPB and C60, we show that higher doping concentrations in both the electron and the hole transport layer increase the built-in voltage, leading to an enhanced short circuit current and solar cell performance.

  18. Optoelectric Properties of GaInP p-i-n Solar Cells with Different i-Layer Thicknesses

    Directory of Open Access Journals (Sweden)

    Tsung-Shine Ko

    2015-01-01

    Full Text Available The optoelectric properties of GaInP p-i-n solar cells with different intrinsic layer (i-layer thicknesses from 0.25 to 1 μm were studied. Both emission intensity and full width at half maximum features of the photoluminescence spectrum indicate that the optimum i-layer thickness would be between 0.5 and 0.75 μm. The integrated current results of photocurrent experiment also point out that the samples with 0.5 to 0.75 μm i-layer thicknesses have optimum value around 156 nA. Electroreflectance measurements reveal that the built-in electric field strength of the sample gradually deviates from the theoretical value larger when i-layer thickness of the sample is thicker than 0.75 μm. I-V measurements also confirm crystal quality for whole samples by obtaining the information about short currents of photovoltaic performances. A series of experiments reflect that thicker i-layer structure would induce more defects generation lowering crystal quality.

  19. High Efficiency Wavelength Conversion of 40 Gbps Signals at 1550 nm in SOI Nano-Rib Waveguides Using p-i-n Diodes

    DEFF Research Database (Denmark)

    Gajda, Andrzej; Da Ros, Francesco; Vukovic, Dragana;

    2013-01-01

    We demonstrate enhancement of FWM wavelength conversion of a 40 Gbps signal in a reverse-biased p-i-n junction silicon waveguide. A conversion efficiency of −4.6 dB enables a conversion power penalty as low as 0.2 dB.......We demonstrate enhancement of FWM wavelength conversion of a 40 Gbps signal in a reverse-biased p-i-n junction silicon waveguide. A conversion efficiency of −4.6 dB enables a conversion power penalty as low as 0.2 dB....

  20. Continuous Wave Phase-Sensitive Four-Wave Mixing in Silicon Waveguides With Reverse-Biased p-i-n Junctions

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Vukovic, Dragana; Gajda, A.;

    2013-01-01

    Phase-sensitive four-wave mixing is experimentally demonstrated using continuous wave pumps in silicon waveguides with p-i-n junctions. The reverse biasing allows decreasing the free carrier lifetime, enabling a phase-sensitive extinction ratio in excess of 15 dB.......Phase-sensitive four-wave mixing is experimentally demonstrated using continuous wave pumps in silicon waveguides with p-i-n junctions. The reverse biasing allows decreasing the free carrier lifetime, enabling a phase-sensitive extinction ratio in excess of 15 dB....

  1. Simulation analysis of the effects of defect density on the performance of p-i-n InGaN solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Movla, Hossein [University of Tabriz, Department of Solid State Physics, Faculty of Physics, Tabriz (Iran, Islamic Republic of); University of Tabriz, Azar Aytash Co., Technology Incubator, Tabriz (Iran, Islamic Republic of); Salami, Davood [University of Tabriz, Department of Solid State Physics, Faculty of Physics, Tabriz (Iran, Islamic Republic of); Sadreddini, Seyed Vahid [Islamic Azad University, Young Researchers Club, Tabriz Branch, Tabriz (Iran, Islamic Republic of)

    2012-11-15

    This paper indicated a simulation study to optimizing the p-i-n InGaN homojunction solar cells. From the simulation results, it was found that optimized value of cell thickness is 1.3 {mu}m and a maximum energy conversion about 20 % can be achieved in 10{sup 15} cm{sup -3} defect concentration. It is shown that i-layer quality is a dominant factor in determining the performance of the cell. This result is consistent with the fact that InGaN p-i-n homojunction solar cell with higher densities of defects and dislocations exhibits a lower J{sub sc} and V{sub oc}, and consequently lower efficiency of the cell. Simulation results demonstrated that high-quality InGaN alloy is necessary to fabricate a high performance cell. (orig.)

  2. Design Issues of GaAs and AlGaAs Delta-Doped p-i-n Quantum-Well APD's

    Science.gov (United States)

    Wang, Yang

    1994-01-01

    We examine the basic design issues in the optimization of GaAs delta-doped and AlGAs delta-doped quantum-well avalanche photodiode (APD) structures using a theoretical analysis based on an ensemble Monte Carlo simulation. The devices are variations of the p-i-n doped quantum-well structure previously described in the literature. They have the same low-noise, high-gain and high-bandwidth features as the p-i-n doped quantum-well device. However, the use of delta doping provides far greater control or the doping concentrations within each stage possibly enhancing the extent to which the device can be depleted. As a result, it is expected that the proposed devices will operate at higher gain levels (at very low noise) than devices previously developed.

  3. Rectification in (La,Sr)MnO3/(Ba,Sr)TiO3/(La,Ce)2CuO4 trilayer p-i-n junctions

    International Nuclear Information System (INIS)

    Oxide trilayer p-i-n junctions, with p-type La0.67Sr0.33MnO3 (LSMO) manganite layer and n-type La1.89Ce0.11CuO4 (LCCO) cuperate layer separated by Ba0.7Sr0.3TiO3 (BST) titanite insulator layer, have been deposited in situ and characterized. With the increment of the insulator layer thickness, the I-V characteristic of such p-i-n junctions changes from symmetric to asymmetric, and then to symmetric again, given the highest rectifying performance at the BST layer of about 25 nm thick. The largest asymmetry, defined as the ratio of dI/dV at +2 V and -2 V, respectively, is found >1000. The insulator layer thickness dependency indicates that the transport properties of the p-i-n junctions are dominated by the interplay between the interior fields at the LSMO/BST and BST/LCCO interfaces

  4. A novel model of photo-carrier screening effect on the GaN-based p-i-n ultraviolet detector

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The photo-carrier density in the depletion region of the GaN-based p-i-n ultraviolet(UV) detector is calculated by solving the photo-carrier continuity equation,and the photo-carrier screening electric field is calculated according to Poisson’s equation.Using the numerical calculation method,a novel model of photo-carrier screening effect is presented.Then the influence of photo-carrier screening effect on the distribution of photo-carrier density in the depletion region of p-i-n detector is discussed.The influence of incident power,bias voltage and carrier life time on the photo-carrier screening effect is also analyzed.It is concluded that the influence of photo-carrier screening effect on the performance of GaN-based p-i-n UV detector is non-monotone,the maximum of carrier drift velocity and the minimum of response time can be realized by adjusting the applied voltage.Besides,the incident light duration has strong impact on the photo-carrier screening effect.

  5. IMAGE INTERPRETATION OF COASTAL AREAS

    Directory of Open Access Journals (Sweden)

    M. A. Lazaridou

    2012-07-01

    Full Text Available Coasts were formed with the overall shape of earth's surface. Τhey represent a landform, as determined by the science of geomorphology. Being the boundary between land and sea, they present important features – particularities such as water currents, waves, winds, estuaries, drainage network, pollution etc. Coasts are examined at various levels: continents – oceans, states – large seas, as for example Mediterranean Sea. Greece, because of its horizontal and vertical partitioning, presents great extent and variety of coasts as mainland, peninsulas and islands. Depending on geomorphology, geology, soils, hydrology, land use of the inland and the coasts themselves, these are very diverse. Photogrammetry and Remote Sensing (defined by Statute II of ISPRS is the art, science, and technology of obtaining reliable information from non-contact imaging and other sensor systems about the Earth and its environment, and other physical objects and of processes through recording, measuring, analyzing and representation. This paper concerns critical considerations on the above. It also includes the case of Thessaloniki coasts in Greece, particularly river estuaries areas (river delta. The study of coastal areas of the wide surroundings of Thessaloniki city includes visual image interpretation – digital image processing techniques on satellite data of high spatial resolution.

  6. Image Interpretation of Coastal Areas

    Science.gov (United States)

    Lazaridou, M. A.

    2012-07-01

    Coasts were formed with the overall shape of earth's surface. Τhey represent a landform, as determined by the science of geomorphology. Being the boundary between land and sea, they present important features - particularities such as water currents, waves, winds, estuaries, drainage network, pollution etc. Coasts are examined at various levels: continents - oceans, states - large seas, as for example Mediterranean Sea. Greece, because of its horizontal and vertical partitioning, presents great extent and variety of coasts as mainland, peninsulas and islands. Depending on geomorphology, geology, soils, hydrology, land use of the inland and the coasts themselves, these are very diverse. Photogrammetry and Remote Sensing (defined by Statute II of ISPRS) is the art, science, and technology of obtaining reliable information from non-contact imaging and other sensor systems about the Earth and its environment, and other physical objects and of processes through recording, measuring, analyzing and representation. This paper concerns critical considerations on the above. It also includes the case of Thessaloniki coasts in Greece, particularly river estuaries areas (river delta). The study of coastal areas of the wide surroundings of Thessaloniki city includes visual image interpretation - digital image processing techniques on satellite data of high spatial resolution.

  7. Enhanced power conversion efficiency of p-i-n type organic solar cells by employing a p-layer of palladium phthalocyanine

    KAUST Repository

    Kim, Inho

    2010-11-15

    We demonstrate an enhancement in the power conversion efficiency (PCE) of p-i-n type organic solar cells consisting of zinc phthalocyanine (ZnPc) and fullerene (C60) using a p-layer of palladium phthalocyanine (PdPc). Solar cells employing three different device structures such as ZnPc/ZnPc:C60/C60, PdPc/PdPc:C60/C60, and PdPc/ZnPc:C60/C60 with varying thickness of mixed interlayers were fabricated by thermal evaporation. The mixed i-layers were deposited by co-evaporation of MPc (M=Zn,Pd) and C60 by 1:1 ratio. PCE of 3.7% was obtained for optimized cells consisting of PdPc/ZnPc:C60/C60, while cells with device structure of ZnPc/ZnPc:C60/C60 showed PCE of 3.2%.

  8. Simulation Study on the Open-Circuit Voltage of Amorphous Silicon p-i-n Solar Cells Using AMPS-1D

    Directory of Open Access Journals (Sweden)

    B.M. Omer

    2014-04-01

    Full Text Available AMPS-1D (Analysis of Microelectronic and Photonic Structure simulation program was used to simulate Amorphous Silicon p-i-n Solar Cell. The simulated result of illuminated current density-voltage characteristics was in a good agreement with experimental values. The dependence of the open-circuit voltage on the characteristics of the a-Si:H intrinsic layer was investigated. The simulation result shows that the open-circuit voltage does not depend on the thickness of the intrinsic layer. The open-circuit voltage decreases when the front contact barrier height is small or the energy gap of the intrinsic layer is small. The open-circuit voltage increases when the distribution of the tail states is sharp or the capture cross sections of these states are small.

  9. Large Perovskite Grain Growth in Low-Temperature Solution-Processed Planar p-i-n Solar Cells by Sodium Addition.

    Science.gov (United States)

    Bag, Santanu; Durstock, Michael F

    2016-03-01

    Thin-film p-i-n type planar heterojunction perovskite solar cells have the advantage of full low temperature solution processability and can, therefore, be adopted in roll-to-roll production and flexible devices. One of the main challenges with these devices, however, is the ability to finely control the film morphology during the deposition and crystallization of the perovskite layer. Processes suitable for optimization of the perovskite layer film morphology with large grains are highly desirable for reduced recombination of charge carriers. Here, we show how uniform thin films with micron size perovskite grains can be made through the use of a controlled amount of sodium ions in the precursor solution. Large micrometer-size CH3NH3PbI3 perovskite grains are formed during low-temperature thin-film growth by adding sodium ions to the PbI2 precursor solution in a two-step interdiffusion process. By adjusting additive concentration, film morphologies were optimized and the fabricated p-i-n planar perovskite-PCBM solar cells showed improved power conversion efficiences (an average of 3-4% absolute efficiency enhancement) compared to the nonsodium based devices. Overall, the additive enhanced grain growth process helped to reach a high 14.2% solar cell device efficiency with low hysteresis. This method of grain growth is quite general and provides a facile way to fabricate large-grained CH3NH3PbI3 on any arbitrary surface by an all solution-processed route. PMID:26862869

  10. Large Perovskite Grain Growth in Low-Temperature Solution-Processed Planar p-i-n Solar Cells by Sodium Addition.

    Science.gov (United States)

    Bag, Santanu; Durstock, Michael F

    2016-03-01

    Thin-film p-i-n type planar heterojunction perovskite solar cells have the advantage of full low temperature solution processability and can, therefore, be adopted in roll-to-roll production and flexible devices. One of the main challenges with these devices, however, is the ability to finely control the film morphology during the deposition and crystallization of the perovskite layer. Processes suitable for optimization of the perovskite layer film morphology with large grains are highly desirable for reduced recombination of charge carriers. Here, we show how uniform thin films with micron size perovskite grains can be made through the use of a controlled amount of sodium ions in the precursor solution. Large micrometer-size CH3NH3PbI3 perovskite grains are formed during low-temperature thin-film growth by adding sodium ions to the PbI2 precursor solution in a two-step interdiffusion process. By adjusting additive concentration, film morphologies were optimized and the fabricated p-i-n planar perovskite-PCBM solar cells showed improved power conversion efficiences (an average of 3-4% absolute efficiency enhancement) compared to the nonsodium based devices. Overall, the additive enhanced grain growth process helped to reach a high 14.2% solar cell device efficiency with low hysteresis. This method of grain growth is quite general and provides a facile way to fabricate large-grained CH3NH3PbI3 on any arbitrary surface by an all solution-processed route.

  11. Large area CMOS image sensors

    International Nuclear Information System (INIS)

    CMOS image sensors, also known as CMOS Active Pixel Sensors (APS) or Monolithic Active Pixel Sensors (MAPS), are today the dominant imaging devices. They are omnipresent in our daily life, as image sensors in cellular phones, web cams, digital cameras, ... In these applications, the pixels can be very small, in the micron range, and the sensors themselves tend to be limited in size. However, many scientific applications, like particle or X-ray detection, require large format, often with large pixels, as well as other specific performance, like low noise, radiation hardness or very fast readout. The sensors are also required to be sensitive to a broad spectrum of radiation: photons from the silicon cut-off in the IR down to UV and X- and gamma-rays through the visible spectrum as well as charged particles. This requirement calls for modifications to the substrate to be introduced to provide optimized sensitivity. This paper will review existing CMOS image sensors, whose size can be as large as a single CMOS wafer, and analyse the technical requirements and specific challenges of large format CMOS image sensors.

  12. Large area CMOS image sensors

    Science.gov (United States)

    Turchetta, R.; Guerrini, N.; Sedgwick, I.

    2011-01-01

    CMOS image sensors, also known as CMOS Active Pixel Sensors (APS) or Monolithic Active Pixel Sensors (MAPS), are today the dominant imaging devices. They are omnipresent in our daily life, as image sensors in cellular phones, web cams, digital cameras, ... In these applications, the pixels can be very small, in the micron range, and the sensors themselves tend to be limited in size. However, many scientific applications, like particle or X-ray detection, require large format, often with large pixels, as well as other specific performance, like low noise, radiation hardness or very fast readout. The sensors are also required to be sensitive to a broad spectrum of radiation: photons from the silicon cut-off in the IR down to UV and X- and gamma-rays through the visible spectrum as well as charged particles. This requirement calls for modifications to the substrate to be introduced to provide optimized sensitivity. This paper will review existing CMOS image sensors, whose size can be as large as a single CMOS wafer, and analyse the technical requirements and specific challenges of large format CMOS image sensors.

  13. Territorial Governance and Area Image

    OpenAIRE

    Nicola Bellini

    2004-01-01

    The image of a region or a city is an emerging topic in most debates about economic development strategies at the local and national level. Local and national policies of innovation which form an essential part of modern policies of local development are less and less an expression of government and increasingly an exercise of governance. The concept that allows best to describe and understand the practical meaning and implications of governance is 'policy network'. The establishment, selecti...

  14. Impedance Spectroscopic Study of p-i-n Type a-Si Solar Cell by Doping Variation of p-Type Layer

    Directory of Open Access Journals (Sweden)

    Sunhwa Lee

    2012-01-01

    Full Text Available We investigated p-i-n type amorphous silicon (a-Si solar cell where the diborane flow rate of the p-type layer was varied and the solar cell was measured static/dynamic characteristics. The p/i interface of the thin film amorphous silicon solar cells was studied in terms of the coordination number of boron atoms in the p layer. p-type layer and p/i interface properties were obtained from the X-ray photoelectron spectroscopy (XPS and impedance spectroscopy. One of the solar cells shows open circuit voltage (oc=880 mV, short circuit current density (sc=14.21 mA/cm2, fill factor (FF=72.03%, and efficiency (=8.8% while the p-type layer was doped with 0.1%. The impedance spectroscopic measurement showed that the diode ideality factor and built-in potential changed with change in diborane flow rate.

  15. Numerical simulation and analysis of the dark and illuminated J-V characteristics of a-Si-H p-i-n diodes

    International Nuclear Information System (INIS)

    Dark and illuminated current-voltage (J-V) characteristics of the hydrogenated amorphous silicon (a-Si:H) p-i-n diode have been simulated by solving numerically the full set of transport equations. The dependence of the dark current on the intrinsic layer (i-layer) thickness and on the measurement temperature is investigated by taking into account the presence of the p/i interface defect states. Good agreement with experimental data is obtained when the p/i interface defect density is increased with increasing i-layer thickness. Further, no appreciable influence was remarked for the i/n interface states on the J-V characteristic, which is in agreement with experimental observations. The numerical simulation also concerned the evaluation of the diode photo-parameters, i.e. the short-circuit current density (Jsc) and the open-circuit voltage (Voc), and reproduced, in a good manner, the light intensity dependence of Jsc and Voc for different i-layer thicknesses

  16. Fabrication and characterization of silicon nanowire p-i-n MOS gated diode for use as p-type tunnel FET

    Science.gov (United States)

    Brouzet, V.; Salem, B.; Periwal, P.; Rosaz, G.; Baron, T.; Bassani, F.; Gentile, P.; Ghibaudo, G.

    2015-11-01

    In this paper, we present the fabrication and electrical characterization of a MOS gated diode based on axially doped silicon nanowire (NW) p-i-n junctions. These nanowires are grown by chemical vapour deposition (CVD) using the vapour-liquid-solid (VLS) mechanism. NWs have a length of about 7 \\upmu {m} with 3 \\upmu {m} of doped regions (p-type and n-type) and 1 \\upmu {m} of intrinsic region. The gate stack is composed of 15 nm of hafnium dioxide ({HfO}2), 80 nm of nickel and 120 nm of aluminium. At room temperature, I_{{on}} =-52 {nA}/\\upmu {m} (V_{{DS}}=-0.5 {V}, V_{{GS}}=-4 {V}), and an I_{{on}}/I_{{off}} ratio of about 104 with a very low I_{{off}} current has been obtained. Electrical measurements are carried out between 90 and 390 K, and we show that the I on current is less temperature dependent below 250 K. We also observe that the ON current is increasing between 250 and 390 K. These transfer characteristics at low and high temperature confirm the tunnelling transport mechanisms in our devices.

  17. High performance planar p-i-n perovskite solar cells with crown-ether functionalized fullerene and LiF as double cathode buffer layers

    International Nuclear Information System (INIS)

    Double cathode buffer layers (CBLs) composed of fullerene derivative functionalized with a crown-ether end group in its side chain (denoted as PCBC) and a LiF layer were introduced between the PCBM acceptor layer and the top cathode in planar p-i-n perovskite solar cells (pero-SCs) based on CH3NH3PbI3−XClX. The devices with the PCBC/LiF double CBLs showed significant improvements in power conversion efficiency (PCE) and long-term stability when compared to the device with LiF single CBL. Through optimizing the spin-coating speed of PCBC, a maximum PCE of 15.53% has been achieved, which is approximately 15% higher than that of the device with single LiF CBL. The remarkable improvement in PCE can be attributed to the formation of a better ohmic contact in the CBL between PCBC and LiF/Al electrode arising from the dipole moment of PCBC, leading to the enhanced fill factor and short-circuit current density (Jsc). Besides the PCE, the long-term stability of the devices with PCBC interlayer is also superior to that of the device with LiF single CBL, which is due to the more effective protection for the perovskite/PCBM interface

  18. Solar-blind Al x Ga1- x N ( x > 0.45) p- i- n photodiodes with a polarization- p-doped emitter

    Science.gov (United States)

    Kuznetsova, N. V.; Nechaev, D. V.; Shmidt, N. M.; Karpov, S. Yu.; Rzheutskii, N. V.; Zemlyakov, V. E.; Kaibyshev, V. Kh.; Kazantsev, D. Yu.; Troshkov, S. I.; Egorkin, V. I.; Ber, B. Ya.; Lutsenko, E. V.; Ivanov, S. V.; Jmerik, V. N.

    2016-06-01

    Polarization-induced p-type doping of AlGaN layers with high aluminum content during plasmaassisted MBE growth has been studied. It is shown that a gradient of the AlN molar fraction in AlGaN (composition gradient) on a level of 0.005 nm-1 must be set in order to obtain a hole concentration of ~1018 cm-3 (measured by the C- V method) in Al x Ga1- x N:Mg ( x = 0.52-0.32) layers with dopant concentration [Mg] = 1.3 × 1018 cm-3. p- i- n photodiodes based on AlGaN heterostructures with such layers as p-emitters showed maximum photoresponsitivity in the solar-blind wavelength range (λ = 281 nm) about 35 and 48 mA/W at reverse bias voltage U = 0 and-5 V, respectively, and exhibited a dark current density of 3.9 × 10-8 A/cm2 at U =-5 V.

  19. High performance planar p-i-n perovskite solar cells with crown-ether functionalized fullerene and LiF as double cathode buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaodong; Zhou, Yi, E-mail: yizhou@suda.edu.cn, E-mail: songbo@suda.edu.cn, E-mail: liyf@iccas.ac.cn; Song, Bo, E-mail: yizhou@suda.edu.cn, E-mail: songbo@suda.edu.cn, E-mail: liyf@iccas.ac.cn [Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); Lei, Ming [Department of Chemistry, Zhejiang University, Hangzhou 310027 (China); Li, Yongfang, E-mail: yizhou@suda.edu.cn, E-mail: songbo@suda.edu.cn, E-mail: liyf@iccas.ac.cn [Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-08-10

    Double cathode buffer layers (CBLs) composed of fullerene derivative functionalized with a crown-ether end group in its side chain (denoted as PCBC) and a LiF layer were introduced between the PCBM acceptor layer and the top cathode in planar p-i-n perovskite solar cells (pero-SCs) based on CH{sub 3}NH{sub 3}PbI{sub 3−X}Cl{sub X}. The devices with the PCBC/LiF double CBLs showed significant improvements in power conversion efficiency (PCE) and long-term stability when compared to the device with LiF single CBL. Through optimizing the spin-coating speed of PCBC, a maximum PCE of 15.53% has been achieved, which is approximately 15% higher than that of the device with single LiF CBL. The remarkable improvement in PCE can be attributed to the formation of a better ohmic contact in the CBL between PCBC and LiF/Al electrode arising from the dipole moment of PCBC, leading to the enhanced fill factor and short-circuit current density (J{sub sc}). Besides the PCE, the long-term stability of the devices with PCBC interlayer is also superior to that of the device with LiF single CBL, which is due to the more effective protection for the perovskite/PCBM interface.

  20. Dependence on the incident light power of the internal electric fields in a GaAs p-i-n solar cell according to bright photoreflectance spectroscopy

    Science.gov (United States)

    Jo, Hyun-Jun; Mun, Young Hee; Kim, Jong Su; Lee, Sang Jun

    2016-07-01

    Bright photoreflectance (BPR) spectroscopy at room temperature is used to examine the internal electric fields in a GaAs p-i-n solar cell for their dependence on the incident light power. Electric fields are observed at 30 µW and 100 µW of incident light. With increasing power, the strengths of the two electric fields are reduced due to the photovoltage effect. The electric field observed at 30 µW is assigned to the p-i interface, which is close to the surface. The other electric field is due to the i-n interface because the incident light penetrates deeper as the light power is increased. The electric field strength of 35.6 kV/cm at the p-i interface is lower than that of 42.9 kV/cm at the i-n interface at 500 µW of light power because the photovoltage effect is proportional to the number of photo-generated carriers, which is reduced as the distance from the surface increases. When the incident light power is similar to the excitation beam power, the electric fields at the p-i interface are saturated.

  1. Correlation between SiH2/SiH and light-induced degradation of p-i-n hydrogenated amorphous silicon solar cells

    Science.gov (United States)

    Keya, Kimitaka; Kojima, Takashi; Torigoe, Yoshihiro; Toko, Susumu; Yamashita, Daisuke; Seo, Hyunwoong; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

    2016-07-01

    We have measured the hydrogen content ratio I SiH2/I SiH associated with Si-H2 and Si-H bonds in p-i-n (PIN) a-Si:H solar cells by Raman spectroscopy. With decreasing I SiH2/I SiH, the efficiency, short-circuit current density, open-circuit voltage, and fill factor of PIN a-Si:H solar cells after light soaking tend to increase. Namely, I SiH2/I SiH correlates well with light-induced degradation of the cells. While a single I-layer has a low I SiH2/I SiH of 0.03-0.09, a PIN cell has I SiH2/I SiH = 0.18 because many Si-H2 bonds exist in the P-layer and at the P/I interface of the PIN solar cells. To realize PIN solar cells with higher stability, we must suppress Si-H2 bond formation in the P-layer and at the P/I interface.

  2. Classification Of Cluster Area Forsatellite Image

    Directory of Open Access Journals (Sweden)

    Thwe Zin Phyo

    2015-06-01

    Full Text Available Abstract This paper describes area classification for Landsat7 satellite image. The main purpose of this system is to classify the area of each cluster contained in a satellite image. To classify this image firstly need to clusterthe satellite image into different land cover types. Clustering is an unsupervised learning method that aimsto classify an image into homogeneous regions. This system is implemented based on color features with K-means clustering unsupervised algorithm. This method does not need to train image before clustering.The clusters of satellite image are grouped into a set of three clusters for Landsat7 satellite image. For this work the combined band 432 from Landsat7 satellite is used as an input. Satellite imageMandalay area in 2001 is chosen to test the segmentation method. After clustering a specific range for three clustered images must be defined in order to obtain greenland water and urbanbalance.This system is implemented by using MATLAB programming language.

  3. Effect of tunable dot charging on photoresponse spectra of GaAs p-i-n diode with InAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Shang, Xiangjun; Yu, Ying; Li, Mifeng; Wang, Lijuan; Zha, Guowei; Ni, Haiqiao; Niu, Zhichuan, E-mail: zcniu@semi.ac.cn [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Pettersson, Håkan [Center for Applied Mathematics and Physics, Halmstad University, P.O. Box 823, S-301 18 Halmstad, Sweden and Solid State Physics/Nanometer Structure Consortium, Lund University, P.O. Box 118, S-221 00 Lund (Sweden); Fu, Ying [Science for Life Laboratory, Department of Applied Physics, Royal Institute of Technology, SE-10691 Stockholm (Sweden)

    2015-12-28

    Quantum dot (QD)-embedded photodiodes have demonstrated great potential for use as detectors. A modulation of QD charging opens intriguing possibilities for adaptive sensing with bias-tunable detector characteristics. Here, we report on a p-i-n GaAs photodiode with InAs QDs whose charging is tunable due to unintentional Be diffusion and trap-assisted tunneling of holes, from bias- and temperature (T)-dependent photocurrent spectroscopy. For the sub-bandgap spectra, the T-dependent relative intensities “QD-s/WL” and “WL/GaAs” (WL: wetting layer) indicate dominant tunneling under −0.9 V (trap-assisted tunneling from the top QDs) and dominant thermal escape under −0.2 ∼ 0.5 V (from the bottom QDs since the top ones are charged and inactive for optical absorption) from the QD s-state, dominant tunneling from WL, and enhanced QD charging at >190 K (related to trap level ionization). For the above-bandgap spectra, the degradation of the spectral profile (especially near the GaAs bandedge) as the bias and T tune (especially under −0.2 ∼ 0.2 V and at >190 K) can be explained well by the enhanced photoelectron capture in QDs with tunable charging. The dominant spectral profile with no degradation under 0.5 V is due to a saturated electron capture in charged QDs (i.e., charging neutralization). QD level simulation and schematic bandstructures can help one understand these effects.

  4. Dynamic cardiac volume imaging using area detectors

    Science.gov (United States)

    Bruder, Herbert; Hoelzel, Arne; Stierstorfer, Karl; Rauscher, Annabella; Flohr, Thomas

    2003-05-01

    We present a reconstruction scheme for dynamic cardiac volume imaging using Area Detector Computed Tomography (CT) named Multi-Sector Cardiac Volume Reconstruction (MCVR) which is based on a 3D-backprojection of the Feldkamp-type. It is intended for circular scanning using area detectors covering the whole heart volume, but the method can easily be extended to cardiac spiral imaging using multi-slice CT. In cardiac imaging with multi-slice CT continuous data acquisition combined with the parallel recording of the patient's ECG enables retrospective gating of data segments for image reconstruction. Using consecutive heart cycles MCVR identifies complementary and time consistent projection data segments ECG. After a row by row parallel rebinning and temporal rebinning the projection data have to be filtered using conventional convolution kernels and finally reconstructed to image space using a 3D-backprojection. A dynamic anthropomorphic computer model of the human heart was developed in order to validate the MCVR approach. A 256-slice detector system with 0.5mm slice collimation was simulated operating in a circular scanning mode at a gantry rotation time of 330ms and compared to state-of-the-art 16-slice technology. At enddiastole the coronary anatomy can be visualized with excellent image quality. Although an area detector with large cone angling covering the entire heart volume was used no cone-artifacts could be observed. Using a 2-sector approach a nearly motion free 3D visualization of the heart chambers was obtained even at endsystole.

  5. Radar image San Francisco Bay Area, California

    Science.gov (United States)

    2000-01-01

    The San Francisco Bay Area in California and its surroundings are shown in this radar image from the Shuttle Radar Topography Mission (SRTM). On this image, smooth areas, such as the bay, lakes, roads and airport runways appear dark, while areas with buildings and trees appear bright. Downtown San Francisco is at the center and the city of Oakland is at the right across the San Francisco Bay. Some city areas, such as the South of Market district in San Francisco, appear bright due to the alignment of streets and buildings with respect to the incoming radar beam. Three of the bridges spanning the Bay are seen in this image. The Bay Bridge is in the center and extends from the city of San Francisco to Yerba Buena and Treasure Islands, and from there to Oakland. The Golden Gate Bridge is to the left and extends from San Francisco to Sausalito. The Richmond-San Rafael Bridge is in the upper right and extends from San Rafael to Richmond. Angel Island is the large island east of the Golden Gate Bridge, and lies north of the much smaller Alcatraz Island. The Alameda Naval Air Station is seen just below the Bay Bridge at the center of the image. Two major faults bounding the San Francisco-Oakland urban areas are visible on this image. The San Andreas fault, on the San Francisco peninsula, is seen on the left side of the image. The fault trace is the straight feature filled with linear reservoirs, which appear dark. The Hayward fault is the straight feature on the right side of the image between the urban areas and the hillier terrain to the east.This radar image was acquired by just one of SRTM's two antennas and, consequently, does not show topographic data, but only the strength of the radar signal reflected from the ground. This signal, known as radar backscatter, provides insight into the nature of the surface, including its roughness, vegetation cover and urbanization. The overall faint striping pattern in the images is a data processing artifact due to the

  6. ASTER Images San Francisco Bay Area

    Science.gov (United States)

    2000-01-01

    These images of the San Francisco Bay region were acquired on March 3, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. Each covers an area 60 kilometers (37 miles) wide and 75 kilometers (47 miles) long. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image the Earth for the next 6 years to map and monitor the changing surface of our planet.Upper Left: The color infrared composite uses bands in the visible and reflected infrared. Vegetation is red, urban areas are gray; sediment in the bays shows up as lighter shades of blue. Thanks to the 15 meter (50-foot) spatial resolution, shadows of the towers along the Bay Bridge can be seen.Upper right: A composite of bands in the short wave infrared displays differences in soils and rocks in the mountainous areas. Even though these regions appear entirely vegetated in the visible, enough surface shows through openings in the vegetation to allow the ground to be imaged.Lower left: This composite of multispectral thermal bands shows differences in urban materials in varying colors. Separation of materials is due to differences in thermal emission properties, analogous to colors in the visible.Lower right: This is a color coded temperature image of water temperature, derived from the thermal bands. Warm waters are in white and yellow, colder waters are blue. Suisun Bay in the upper right is fed directly from the cold Sacramento River. As the water flows through San Pablo and San Francisco Bays on the way to the Pacific, the waters warm up.Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for

  7. A system and method for imaging body areas

    NARCIS (Netherlands)

    Goethals, F.P.C.

    2013-01-01

    The invention relates to a system for imaging one or more external human body areas comprising a photographic device configured to acquire, store and output an image or images of the one or more body areas. The invention also relates to a method for determining a probable disease state of an externa

  8. Performance evaluation of high-detectivity p-i-n infrared photodetector based on compressively-strained Ge0.964Sn0.036/Ge multiple quantum wells by quantum modelling

    International Nuclear Information System (INIS)

    GeSn/Ge p-i-n photodetectors with practical Ge0.964Sn0.036 active layers are theoretically investigated. First, we calculated the electronic band parameters for the heterointerfaces between strained Ge1−xSnx and relaxed (001)-oriented Ge. The carrier transport in a p-i-n photodiode built on a ten-period Ge0.964Sn0.036/Ge multiple quantum well absorber was then analyzed and numerically simulated within the Tsu−Esaki formalism by self-consistently solving the Schrödinger and Poisson equations, coupled to the kinetic rate equations. Photodetection up to a 2.1 μm cut-off wavelength is achieved. High responsivities of 0.62 A W−1 and 0.71 A W−1 were obtained under a reverse bias voltage of −3 V at peak wavelengths of 1550 nm and 1781 nm, respectively. Even for this low Sn-fraction, it is found that the photodetector quantum efficiency (49%@1.55 μm) is higher than those of comparable pure-Ge devices at room temperature. Detectivity of 3.8 × 1010 cm Hz1/2 W−1 and 7.9 × 1010 cm Hz1/2 W−1 at −1 V and −0.5 V, respectively, is achievable at room temperature for a 1550 nm wavelength peak of responsivity. This work represents a step forward in developing GeSn/Ge based infrared photodetectors. (paper)

  9. IMAGE PROCESSING METHOD TO MEASURE SUGARCANE LEAF AREA

    Directory of Open Access Journals (Sweden)

    Sanjay B. Patil

    2011-08-01

    Full Text Available In order to increase the average sugarcane yield per acres with minimum cost farmers are adapting precision farming technique. This paper includes the area measurement of sugarcane leaf based on image processing method which is useful for plants growth monitoring, to analyze fertilizer deficiency and environmental stress,to measure diseases severity. In image processing method leaf area is calculated through pixel number statistic. Unit pixel in the same digital images represent the same size hence from known reference area and pixel count, unit pixel size can calculate, so that it is easy to calculate leaf area by counting total pixel in leaf area region. The results are compared with the results of graphical area measurement method. The experimentally it is proved that image processing method for measuring sugarcane leaf area is accurate and strong practicabilitywith small relative error.

  10. Digital Retinal Images: Background and Damaged Areas Segmentation

    Directory of Open Access Journals (Sweden)

    Eman A. Gani

    2014-07-01

    Full Text Available Digital retinal images are more appropriate for automatic screening of diabetic retinopathy systems. Unfortunately, a significant percentage of these images are poor quality that hiders further analysis due to many factors (such as patient movement, inadequate or non-uniform illumination, acquisition angle and retinal pigmentation. The retinal images of poor quality need to be enhanced before the extraction of features and abnormalities. So, the segmentation of retinal image is essential for this purpose, the segmentation is employed to smooth and strengthen image by separating the background and damaged areas from the overall image thus resulting in retinal image enhancement and less processing time. In this paper, methods for segmenting colored retinal image are proposed to improve the quality of retinal image diagnosis. The methods generates two segmentation masks; i.e., background segmentation mask for extracting the background area and poor quality mask for removing the noisy areas from retinal image. The standard retinal image databases DIARETDB0, DIARETDB1, STARE, DRIVE and some images obtained from ophthalmologists have been used to test the validation of the proposed segmentation technique. Experimental results indicate the introduced methods are effective and can lead to high segmentation accuracy

  11. Interface areas complexity characterization of echographic images

    Energy Technology Data Exchange (ETDEWEB)

    Capri, Arnaud [LVR, Orleans University, IUT de Bourges, 63 avenue de Lattre de Tassigny, 18020 Bourges (France); SINTERS GROUP SAS, 5 rue Paul Mesple, BP 1311, 31106 ToulouseCedex 01 (France)]. E-mail: Arnaud.Capri@bourges.univ-orleans.fr; Vincent, Nicole [CRIP5-SIP, Rene Descartes University-Paris 5, 45 rue des Saints-Peres, 75270 Paris Cedex 06 (France); Vieyres, Pierre [LVR, Orleans University, IUT de Bourges, 63 avenue de Lattre de Tassigny, 18020 Bourges (France); Poisson, Gerard [LVR, Orleans University, IUT de Bourges, 63 avenue de Lattre de Tassigny, 18020 Bourges (France); Makris, Pascal [LI, University Francois Rabelais of Tours, 64 avenue Jean Portalis, 37200 Tours (France)

    2006-12-20

    The telemedicine concept integrates images, video acquisition and video transfer which are usually managed by using a standard videoconference system. Very often, the initial blur of echography pictures makes it difficult to use standard segmentation techniques such as snakes or Sobel filters which aid the doctor in making his decision. In medical echography practice, contour properties of an organ are often more relevant to decipher the presence of pathologies than the exact lineout of the contour itself. The processing, via the fuzzy approach, enables us to subdivide an image in different classes: one gathering the homogeneous zones (pixels belonging to a medium) and the other gathering more heterogeneous zones (e.g. transition between two media). Complexity measurement of each region can be approximated by the calculation of a fractal dimension. Thus, we can obtain interface complexity without having to extract the interfaces themselves. Finally, the link between fractal dimension and fuzzy rate is carried out.

  12. Satellite image collection modeling for large area hazard emergency response

    Science.gov (United States)

    Liu, Shufan; Hodgson, Michael E.

    2016-08-01

    Timely collection of critical hazard information is the key to intelligent and effective hazard emergency response decisions. Satellite remote sensing imagery provides an effective way to collect critical information. Natural hazards, however, often have large impact areas - larger than a single satellite scene. Additionally, the hazard impact area may be discontinuous, particularly in flooding or tornado hazard events. In this paper, a spatial optimization model is proposed to solve the large area satellite image acquisition planning problem in the context of hazard emergency response. In the model, a large hazard impact area is represented as multiple polygons and image collection priorities for different portion of impact area are addressed. The optimization problem is solved with an exact algorithm. Application results demonstrate that the proposed method can address the satellite image acquisition planning problem. A spatial decision support system supporting the optimization model was developed. Several examples of image acquisition problems are used to demonstrate the complexity of the problem and derive optimized solutions.

  13. Compressively strained SiGe band-to-band tunneling model calibration based on p-i-n diodes and prospect of strained SiGe tunneling field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kao, Kuo-Hsing; Meyer, Kristin De [imec, Kapeldreef 75, 3001 Leuven (Belgium); Department of Electrical Engineering, KU Leuven, Leuven (Belgium); Verhulst, Anne S.; Rooyackers, Rita; Douhard, Bastien; Delmotte, Joris; Bender, Hugo; Richard, Olivier; Vandervorst, Wilfried; Simoen, Eddy; Hikavyy, Andriy; Loo, Roger; Arstila, Kai; Collaert, Nadine; Thean, Aaron; Heyns, Marc M. [imec, Kapeldreef 75, 3001 Leuven (Belgium)

    2014-12-07

    Band-to-band tunneling parameters of strained indirect bandgap materials are not well-known, hampering the reliability of performance predictions of tunneling devices based on these materials. The nonlocal band-to-band tunneling model for compressively strained SiGe is calibrated based on a comparison of strained SiGe p-i-n tunneling diode measurements and doping-profile-based diode simulations. Dopant and Ge profiles of the diodes are determined by secondary ion mass spectrometry and capacitance-voltage measurements. Theoretical parameters of the band-to-band tunneling model are calculated based on strain-dependent properties such as bandgap, phonon energy, deformation-potential-based electron-phonon coupling, and hole effective masses of strained SiGe. The latter is determined with a 6-band k·p model. The calibration indicates an underestimation of the theoretical electron-phonon coupling with nearly an order of magnitude. Prospects of compressively strained SiGe tunneling transistors are made by simulations with the calibrated model.

  14. Editorial. The multiple sights area. Diverged images

    Directory of Open Access Journals (Sweden)

    Luis Porta

    2011-12-01

    Full Text Available This second issue of the Journal for Educators, Teachers and Trainers offers articles that address complex issues associated with Education, Teachers/professors and Students. We can distinguish three large thematic blocks: the first linked to Higher Education as well as debates and discussions on the academic profession, the University- Society- Knowledge dynamics besides the redefinition of roles/teaching responsibilities in view of the emergence of "new students" for "new professions". The second block is associated with vocational training or education throughout life, and the third block deals with epistemological and methodological topics of the teaching in different areas and educational levels. These various sights over converging questions allows us to reset an agenda starting from constant reflection and experiencies exchange, to think alternative ways of solving education problems.

  15. IMAGE PROFILE AREA CALCULATION BASED ON CIRCULAR SAMPLE MEASUREMENT CALIBRATION

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A practical approach of measurement calibration is presented for obtaining the true area of the photographed objects projected in the 2-D image scene. The calibration is performed using three circular samples with given diameters. The process is first to obtain the ratio mm/pixel in two orthogonal directions, and then use the obtained ratios with the total number of pixels scanned within projected area of the object of interest to compute the desired area. Compared the optically measured areas with their corresponding true areas, the results show that the proposed method is quite encouraging and the relevant application also proves the approach adequately accurate.

  16. Damage Degree Evaluation of Earthquake Area Using UAV Aerial Image

    Directory of Open Access Journals (Sweden)

    Jinhong Chen

    2016-01-01

    Full Text Available An Unmanned Aerial Vehicle (UAV system and its aerial image analysis method are developed to evaluate the damage degree of earthquake area. Both the single-rotor and the six-rotor UAVs are used to capture the visible light image of ground targets. Five types of typical ground targets are considered for the damage degree evaluation: the building, the road, the mountain, the riverway, and the vegetation. When implementing the image analysis, first the Image Quality Evaluation Metrics (IQEMs, that is, the image contrast, the image blur, and the image noise, are used to assess the imaging definition. Second, once the image quality is qualified, the Gray Level Cooccurrence Matrix (GLCM texture feature, the Tamura texture feature, and the Gabor wavelet texture feature are computed. Third, the Support Vector Machine (SVM classifier is employed to evaluate the damage degree. Finally, a new damage degree evaluation (DDE index is defined to assess the damage intensity of earthquake. Many experiment results have verified the correctness of proposed system and method.

  17. Area efficient image compression using wave Decoding at chip level

    Directory of Open Access Journals (Sweden)

    K. Ambika

    2013-03-01

    Full Text Available Abstract-- The recent emergence of new applications in area of wireless network based on low bandwidth protocols such as Zig Bee (up to 250Kbps and Bluetooth (up to 1Mbps and some biomedical applications (wireless camera pill have created some challenges in the field of image processing. This can be overcome by the technique called “Image Compression”. This paper proposes a new colour image compression technique based on quad tree decomposition. To reduce the computational complexity, the quad tree decomposition is applied on to each block of the image instead of applying it to the entire image. The experimental results have indicated that the performance of the suggested method is much better when compared to most popular existing encoders.

  18. Feature-Area Optimization: A Novel SAR Image Registration Method

    OpenAIRE

    Liu, Fuqiang; Bi, Fukun; Chen, Liang; Shi, Hao; Liu, Wei

    2016-01-01

    This letter proposes a synthetic aperture radar (SAR) image registration method named Feature-Area Optimization (FAO). First, the traditional area-based optimization model is reconstructed and decomposed into three key but uncertain factors: initialization, slice set and regularization. Next, structural features are extracted by scale invariant feature transform (SIFT) in dual-resolution space (SIFT-DRS), a novel SIFT-Like method dedicated to FAO. Then, the three key factors are determined ba...

  19. Enhancement of Substrate Doping Concentration on EL of p-i-n Structure%衬底掺杂浓度对p-i-n结构电致发光的增强作用

    Institute of Scientific and Technical Information of China (English)

    陈德媛; 冒昌银; 刘宇; 孙红程

    2011-01-01

    p-I-n structure was prepared in plasma enhanced chemical vapour deposition system applying the in situ oxidization and doping technologies, with nc-Si/SiO2 multilayers as the intrinsic layer, P-doped and B-doped a-Si as the n and p regions. Heavily and lightly doped p type single crystal silicon wafers as substrates. The heavily doped p+ silicon lowered the tunnelling barrier for carriers,especially for holes,increasing effective carrier injection efficiency, providing more holes to participate in the recombination, and then increasing electroluminescence efficiency effectively;On the other hand,the heavily doped substrate decreased the whole series resistance, lowering the turn-on voltage from 5 V to 3 V. The above two factors make the electroluminescence property of the device on the heavily doped substrate better than that on lightly doped p type substrate.%采用等离子体增强化学气相淀积系统,应用原位氧化和原位掺杂技术制备出了以非晶硅/二氧化硅多层膜结构为本征i层、分别以磷和硼掺杂的非晶硅作为n型和p型区的p-i-n结构.经过三步后退火处理,i层晶化得到纳米硅/二氧化硅多层膜结构,磷和硼掺杂的非晶硅结晶形成多晶硅结构.衬底采用轻和重掺杂两种不同浓度的p型单晶硅.重掺杂衬底上的p-i-n结构的电致发光特性比轻掺杂的具有更低的开启电压和更高的发光强度和效率.根据载流子的输运机制分析,重掺杂的p+硅衬底一方面有效的降低了载流子的隧穿势垒,提高了载流子的有效注入效率,进而提高了电致发光强度和效率;另一方面,重掺杂衬底也降低了器件的总串联电阻,是器件开启电压降低的主要原因.

  20. Cartridge case image matching using effective correlation area based method.

    Science.gov (United States)

    Yammen, S; Muneesawang, P

    2013-06-10

    A firearm leaves a unique impression on fired cartridge cases. The cross-correlation function plays an important role in matching the characteristic features on the cartridge case found at the crime scene with a specific firearm, for accurate firearm identification. This paper proposes that the computational forensic techniques of alignment and effective correlation area-based approaches to image matching are essential to firearm identification. Specifically, the reference and the corresponding cartridge cases are aligned according to the phase-correlation criterion on the transform domain. The informative segments of the breech face marks are identified by a cross-covariance coefficient using the coefficient value in a window located locally in the image space. The segments are then passed to the measurement of edge density for computing effective correlation areas. Experimental results on a new dataset show that the correlation system can make use of the best properties of alignment and effective correlation area-based approaches, and can attain significant improvement of image-correlation results, compared with the traditional image-matching methods for firearm identification, which employ cartridge-case samples. An analysis of image-alignment score matrices suggests that all translation and scaling parameters are estimated correctly, and contribute to the successful extraction of effective correlation areas. It was found that the proposed method has a high discriminant power, compared with the conventional correlator. This paper advocates that this method will enable forensic science to compile a large-scale image database to perform correlation of cartridge case bases, in order to identify firearms that involve pairwise alignments and comparisons.

  1. Peripheral nerve imaging: Not only cross-sectional area.

    Science.gov (United States)

    Tagliafico, Alberto Stefano

    2016-08-28

    Peripheral nerve imaging is recognized as a complement to clinical and neurophysiological assessment in the evaluation of peripheral nerves with the ability to impact patient management, even for small and difficult nerves. The European Society of Musculoskeletal Radiology, suggest to use ultrasound (US) for nerve evaluation due to the fact that, in sever anatomical area, magnetic resonance imaging is not able to give additional informations. US could be considered the first-choice approach for the assessment of peripheral nerves. The relative drawback of peripheral nerve US is the long learning curve and the deep anatomic competence to evaluate even small nerves. In the recent years, the role of US in peripheral nerve evaluation has been widened. In the past, nerve US was mainly used to assess nerve-cross sectional area, but now more advanced measurements and considerations are desirable and can boost the role of peripheral nerve US. Nerve echotexture evaluation was defined in 2010: The ratio between the hypoechoic and hyperechoic areas of peripheral nerves on US was called "nerve density". For evaluation of patients who have peripheral neuropathies, the role of peripheral nerve is US wider than simple cross-sectional area evaluation. Quantitative measurements describing the internal fascicular echotexture of peripheral nerves introduce the concept of considering US as a possible quantitative imaging biomarker technique. The potential of nerve US has started to be uncovered. It seems clear that only cross-sectional area measurement is no more sufficient for a comprehensive US evaluation of peripheral nerves. PMID:27648165

  2. Peripheral nerve imaging: Not only cross-sectional area.

    Science.gov (United States)

    Tagliafico, Alberto Stefano

    2016-08-28

    Peripheral nerve imaging is recognized as a complement to clinical and neurophysiological assessment in the evaluation of peripheral nerves with the ability to impact patient management, even for small and difficult nerves. The European Society of Musculoskeletal Radiology, suggest to use ultrasound (US) for nerve evaluation due to the fact that, in sever anatomical area, magnetic resonance imaging is not able to give additional informations. US could be considered the first-choice approach for the assessment of peripheral nerves. The relative drawback of peripheral nerve US is the long learning curve and the deep anatomic competence to evaluate even small nerves. In the recent years, the role of US in peripheral nerve evaluation has been widened. In the past, nerve US was mainly used to assess nerve-cross sectional area, but now more advanced measurements and considerations are desirable and can boost the role of peripheral nerve US. Nerve echotexture evaluation was defined in 2010: The ratio between the hypoechoic and hyperechoic areas of peripheral nerves on US was called "nerve density". For evaluation of patients who have peripheral neuropathies, the role of peripheral nerve is US wider than simple cross-sectional area evaluation. Quantitative measurements describing the internal fascicular echotexture of peripheral nerves introduce the concept of considering US as a possible quantitative imaging biomarker technique. The potential of nerve US has started to be uncovered. It seems clear that only cross-sectional area measurement is no more sufficient for a comprehensive US evaluation of peripheral nerves.

  3. Urban area structuring mapping using an airborne polarimetric SAR image

    Science.gov (United States)

    Simonetto, Elisabeth; Malak, Charbel

    2009-09-01

    For several years, image classification and pattern recognition algorithms have been developed for the land coverage mapping using radar and multispectral imagery with medium to large pixel size. As several satellites now distribute submetric-pixel and metric-pixel images (for example QUICKBIRD,TERRASAR-X), the research turns to the study of the structure of cities: building structuring, grassy areas, road networks, etc, and the physical description of the urban surfaces. In that context, we propose to underline new potentialities of submetric-pixel polarimetric SAR images. We deal with the characterization of roofs and the mapping of trees. For that purpose, a first analysis based on photo-interpretation and the assessement of several polarimetric descriptors is carried out. Then, an image classification scheme is built using the polarimetric H/alpha-Wishart algorithm, followed by a decision tree. This one is based on the most pertinent polarimetric descriptors and aims at reducing the classification errors. The result proves the potential of such data. Our work relies on an image of a suburban area, acquired by the airborne RAMSES SAR sensor of ONERA.

  4. Penumbral imaging and numerical evaluation of large area source neutron imaging system

    Institute of Scientific and Technical Information of China (English)

    WU YueLei; HU HuaSi; ZHANG BoPing; LI LinBo; CHEN Da; SHAN Qing; ZHU Jie

    2009-01-01

    The fusion neutron penumbral imaging system Monte Carlo model was established. The transfer func-tions of the two discrete units in the neutron source were obtained in two situations: Imaging in geo-metrical near-optical and real situation. The spatial resolutions of the imaging system in two situations were evaluated and compared. The penumbral images of four units in the source were obtained by means of 2-dimensional (2D) convolution and Monte Carlo simulation. The penumbral images were reconstructed with the same method of filter. The same results were confirmed. The encoding essence of penumbral imaging was revealed. With MCNP(Monte Carlo N-particle) simulation, the neutron pen-umbral images of the large area source (200 μm×200 μm) on scintillation fiber array were obtained. The improved Wiener filter method was used to reconstruct the penumbral image and the source image was obtained. The results agree with the preset neutron source image. The feasibility of the neutron imaging system was verified.

  5. Penumbral imaging and numerical evaluation of large area source neutron imaging system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The fusion neutron penumbral imaging system Monte Carlo model was established. The transfer functions of the two discrete units in the neutron source were obtained in two situations:Imaging in geometrical near-optical and real situation. The spatial resolutions of the imaging system in two situations were evaluated and compared. The penumbral images of four units in the source were obtained by means of 2-dimensional (2D) convolution and Monte Carlo simulation. The penumbral images were reconstructed with the same method of filter. The same results were confirmed. The encoding essence of penumbral imaging was revealed. With MCNP(Monte Carlo N-particle) simulation,the neutron penumbral images of the large area source (200 μm×200 μm) on scintillation fiber array were obtained. The improved Wiener filter method was used to reconstruct the penumbral image and the source image was obtained. The results agree with the preset neutron source image. The feasibility of the neutron imaging system was verified.

  6. A System to Detect Residential Area in Multispectral Satellite Images

    Directory of Open Access Journals (Sweden)

    Seyfallah Bouraoui

    2011-11-01

    Full Text Available In this paper, we propose a new solution to extract complex structures from High-Resolution (HR remote-sensing images. We propose to represent shapes and there relations by using region adjacency graphs. They are generated automatically from the segmented images. Thus, the nodes of the graph represent shape like houses, streets or trees, while arcs describe the adjacency relation between them. In order to be invariant to transformations such as rotation and scaling, the extraction of objects of interest is done by combining two techniques: one based on roof color to detect the bounding boxes of houses, and one based on mathematical morphology notions to detect streets. To recognize residential areas, a model described by a regular language is built. The detection is achieved by looking for a path in the region adjacency graph, which can be recognized as a word belonging to the description language. Our algorithm was tested with success on images from the French satellite SPOT 5 representing the urban area of Strasbourg (France at different spatial resolution.

  7. p-i-n/n-i-p type planar hybrid structure of highly efficient perovskite solar cells towards improved air stability: synthetic strategies and the role of p-type hole transport layer (HTL) and n-type electron transport layer (ETL) metal oxides.

    Science.gov (United States)

    Mali, Sawanta S; Hong, Chang Kook

    2016-05-19

    There has been fast recent progress in perovskite solar cells (PSCs) towards low cost photovoltaic technology. Organometal mixed halide (MAPbX or FAPbX) perovskites are the most promising light absorbing material sandwiched between the electron transport layer (ETL) and hole transport layer (HTL). These two layers play a critical role in boosting the power conversion efficiency (PCE) and maintaining air stability. However, the device stability is a serious issue in regular as well as p-i-n inverted type perovskite solar cells. This mini-review briefly outlines the state-of-art of p-i-n/n-i-p type planar hybrid perovskite solar cells using MAPbX/FAPbX perovskite absorbing layers. Later, we will focus on recent trends, progress and further opportunities in exploring the air stable hybrid planar structure PSCs.

  8. p-i-n/n-i-p type planar hybrid structure of highly efficient perovskite solar cells towards improved air stability: synthetic strategies and the role of p-type hole transport layer (HTL) and n-type electron transport layer (ETL) metal oxides

    Science.gov (United States)

    Mali, Sawanta S.; Hong, Chang Kook

    2016-05-01

    There has been fast recent progress in perovskite solar cells (PSCs) towards low cost photovoltaic technology. Organometal mixed halide (MAPbX or FAPbX) perovskites are the most promising light absorbing material sandwiched between the electron transport layer (ETL) and hole transport layer (HTL). These two layers play a critical role in boosting the power conversion efficiency (PCE) and maintaining air stability. However, the device stability is a serious issue in regular as well as p-i-n inverted type perovskite solar cells. This mini-review briefly outlines the state-of-art of p-i-n/n-i-p type planar hybrid perovskite solar cells using MAPbX/FAPbX perovskite absorbing layers. Later, we will focus on recent trends, progress and further opportunities in exploring the air stable hybrid planar structure PSCs.

  9. Area and power efficient DCT architecture for image compression

    Science.gov (United States)

    Dhandapani, Vaithiyanathan; Ramachandran, Seshasayanan

    2014-12-01

    The discrete cosine transform (DCT) is one of the major components in image and video compression systems. The final output of these systems is interpreted by the human visual system (HVS), which is not perfect. The limited perception of human visualization allows the algorithm to be numerically approximate rather than exact. In this paper, we propose a new matrix for discrete cosine transform. The proposed 8 × 8 transformation matrix contains only zeros and ones which requires only adders, thus avoiding the need for multiplication and shift operations. The new class of transform requires only 12 additions, which highly reduces the computational complexity and achieves a performance in image compression that is comparable to that of the existing approximated DCT. Another important aspect of the proposed transform is that it provides an efficient area and power optimization while implementing in hardware. To ensure the versatility of the proposal and to further evaluate the performance and correctness of the structure in terms of speed, area, and power consumption, the model is implemented on Xilinx Virtex 7 field programmable gate array (FPGA) device and synthesized with Cadence® RTL Compiler® using UMC 90 nm standard cell library. The analysis obtained from the implementation indicates that the proposed structure is superior to the existing approximation techniques with a 30% reduction in power and 12% reduction in area.

  10. Object detection in rural areas using hyperspectral imaging

    Science.gov (United States)

    Ozturk, Safak; Emre Esin, Yunus; Artan, Yusuf

    2015-10-01

    Object detection has gained considerable interest in remote sensing community with a broad range of applications including the remote monitoring of building development in rural areas. Many earlier studies on this task performed their analysis using either multispectral satellite imagery or color images obtained via an aerial vehicle. In recent years, hyperspectral imaging (HSI) has emerged as an alternative technique for remote monitoring of building developments. Unlike other imaging techniques, HSI provides a continuous spectral signature of the objects in the field of view (FOV) which facilitates the separation among different objects. In general, spectral signature similarity between objects often causes a significant amount of false alarm (FA) rate that adversely effects the overall accuracy of these systems. In order to reduce the high rate of FA posed by the pixel-wise classification, we propose a novel rural building detection method that utilizes both spatial information and spectral signature of the pixels. Proposed technique consists of three parts; a spectral signature classifier, watershed based superpixel map and an oriented-gradient filters based object detector. In our analysis, we have evaluated the performance of proposed approach using hyperspectral image dataset obtained at various elevation levels, namely 500 meters and 3000 meters. NEO HySpex VNIR-1800 camera is used for 182 band hyperspectral data acquisition. First 155 band is used due to the atmospheric effects on the last bands. Performance comparison between the proposed technique and the pixel-wise spectral classifier indicates a reduction in sensitivity rate but a notable increase in specificity and overall accuracy rates. Proposed method yields sensitivity, specificity, accuracy rate of 0.690, 0.997 and 0.992, respectively, whereas pixel-wise classification yields sensitivity, specificity, and accuracy rate of 0.758, 0.983, 0.977, respectively. Note that the sensitivity reduction is

  11. Classification of remote sensing images from urban areas using Laplacian image and Bayesian theory

    Science.gov (United States)

    Yousefi, B.; Mirhassani, S. M.; Marvi, H.

    2007-10-01

    This paper presents the methodology of urban area classification in high resolution satellite IKONOS imagery. The strategies include building extraction by Bayesian theory and laplacian criterion, labeling and size filtering, intensity threshold and etc which are applied to IKONOS image in tandem to make this algorithm as an effective strategy to save processing time and improve robustness. To realize the strategy, First, vegetation are extracted in attend to green layer of RGB image then buildings are detected by Bayesian decision theory in regard to laplacian probability density function, then shadows which have low intensity are detected. In the next step a special intensity level is calculated as a threshold level to discern roads. Finally open areas are extracted from remained of image as regions with low laplacian intensity and large size. Meanwhile morphological operations are applied to remove redundant image's particles. Experimental result indicates that this approach has a high efficiency especially in extraction of large roads and streets from dense urban area IKNOS images.

  12. Stereoscopic imaging: filling disoccluded areas in depth image-based rendering

    Science.gov (United States)

    Vázquez, Carlos; Tam, Wa James; Speranza, Filippo

    2006-10-01

    Depth image based rendering (DIBR) is a method for converting 2D material to stereoscopic 3D. With DIBR, information contained in a gray-level (luminance intensity) depth map is used to shift pixels in the 2D image to generate a new image as if it were captured from a new viewpoint. The larger the shift (binocular parallax), the larger is the perceived depth of the generated stereoscopic pair. However, a major problem with DIBR is that the shifted pixels now occupy new positions and leave areas that they originally occupied "empty." These disoccluded regions have to be filled properly, otherwise they can degrade image quality. In this study we investigated different methods for filling these disoccluded regions: (a) Filling regions with a constant color, (b) filling regions with horizontal linear interpolation of values on the hole border, (c) solving the Laplace equation on the hole boundary and propagate the values inside the region, (d) horizontal extrapolation with depth information taken into account, (e) variational inpainting with depth information taken into account, and (f) preprocessing of the depth map to prevent disoccluded regions from appearing. The methods differed in the time required for computing and filling, and the appearance of the filled-in regions. We assessed the subjective image quality outcome for several stereoscopic test images in which the left-eye view was the source and the right-eye view was a rendered view, in line with suggestions in the literature for the asymmetrical coding of stereoscopic images.

  13. Validation of velocity map imaging conditions over larger areas

    Science.gov (United States)

    Reid, Mike; Koehler, Sven P. K.

    2013-04-01

    We have established through simulations and experiments the area over which Velocity Map Imaging (VMI) conditions prevail. We designed a VMI setup in which we can vary the ionization position perpendicular to the center axis of the time-of-flight spectrometer. We show that weak extraction conditions are far superior over standard three-plate setups if the aim is to increase the ionization volume without distorting VMI conditions. This is important for a number of crossed molecular beam experiments that already utilize weak extraction conditions, but to a greater extent for surface studies where fragments are desorbed or scattered off a surface in all directions. Our results on the dissociation of NO2 at 226 nm show that ionization of the fragments can occur up to ±5.5 mm away from the center axis of the time-of-flight spectrometer without affecting resolution or arrival position.

  14. Validation of velocity map imaging conditions over larger areas

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Mike; Koehler, Sven P. K. [School of Chemistry, University of Manchester, M13 9PL Manchester (United Kingdom); Photon Science Institute, University of Manchester, M13 9PL Manchester (United Kingdom); Dalton Cumbrian Facility, University of Manchester, Moor Row, CA24 3HA Whitehaven (United Kingdom)

    2013-04-15

    We have established through simulations and experiments the area over which Velocity Map Imaging (VMI) conditions prevail. We designed a VMI setup in which we can vary the ionization position perpendicular to the center axis of the time-of-flight spectrometer. We show that weak extraction conditions are far superior over standard three-plate setups if the aim is to increase the ionization volume without distorting VMI conditions. This is important for a number of crossed molecular beam experiments that already utilize weak extraction conditions, but to a greater extent for surface studies where fragments are desorbed or scattered off a surface in all directions. Our results on the dissociation of NO{sub 2} at 226 nm show that ionization of the fragments can occur up to {+-}5.5 mm away from the center axis of the time-of-flight spectrometer without affecting resolution or arrival position.

  15. 结构参数对p-i-n结构InGaN太阳能电池性能的影响及机理%Influence of structure parameters on the performance of p-i-n InGaN solar cell

    Institute of Scientific and Technical Information of China (English)

    周梅; 赵德刚

    2012-01-01

    The effect of structure parameters on the performance of p-i-n InGaN solar cell is investigated by theoretical calculation. It is found that the short-circuit current decreases while the open-circuit voltage increases with the increase of bandgap of InGaN material. The maximal energy conversion efficiency of p-i-n homojunction InGaN solar cell can be obtained when the bandgap of InGaN is around 1.5 eV. It is also found that the energy conversion efficiency can be improved by appropriately increasing bandgap of p-InGaN p-i-n heterojunction InGaN solar cell, in addition, the efficiency of p-i-n heterojunction InGaN solar cell may be increased further by employing the back electric filed structure. The simulation results suggest that performance of InGaN solar cell can be improved by employing p-i-n heterojunction structure if the appropriate bandgaps of p-InGaN and n-InGaN are adopted.%研究了器件结构参数对p-i—n结构InGaN单结太阳能电池性能的影响及物理机制.模拟结果发现:随着InGaN禁带宽度的增加,InGaN电池的短路电流减小,但同时开路电压增加,当InGaN层的禁带宽度为1.5eV左右时,同质p-i—n结InGaN电池的效率最高,并计算了不同厚度的i层对InGaN电池效率的影响.进一步的计算表明,适当采用带宽更大的p-InGaN层形成异质p-i—n结InGaN电池可以获得更高效率,但是p-InGaN层带宽过大也会导致电池的效率急剧下降.研究还发现,采用禁带宽度更大的n—InGaN层可以形成背电场,从而增加p-i—n结InGaN太阳电池的效率.研究结果表明,适当选择P—InGaN和n-InGaN禁带宽度形成异质P—i—n结可以提高InGaN太阳能电池效率.

  16. An area efficient readout architecture for photon counting color imaging

    International Nuclear Information System (INIS)

    The introduction of several energy levels, namely color imaging, in photon counting X-ray image sensors is a trade-off between circuit complexity and spatial resolution. In this paper, we propose a pixel architecture that has full resolution for the intensity and uses sub-sampling for the energy spectrum. The results show that this sub-sampling pixel architecture produces images with an image quality which is, on average, 2.4 dB (PSNR) higher than those for a single energy range architecture and with half the circuit complexity of that for a full sampling architecture

  17. Fuzzy logic color detection: Blue areas in melanoma dermoscopy images.

    Science.gov (United States)

    Lingala, Mounika; Stanley, R Joe; Rader, Ryan K; Hagerty, Jason; Rabinovitz, Harold S; Oliviero, Margaret; Choudhry, Iqra; Stoecker, William V

    2014-07-01

    Fuzzy logic image analysis techniques were used to analyze three shades of blue (lavender blue, light blue, and dark blue) in dermoscopic images for melanoma detection. A logistic regression model provided up to 82.7% accuracy for melanoma discrimination for 866 images. With a support vector machines (SVM) classifier, lower accuracy was obtained for individual shades (79.9-80.1%) compared with up to 81.4% accuracy with multiple shades. All fuzzy blue logic alpha cuts scored higher than the crisp case. Fuzzy logic techniques applied to multiple shades of blue can assist in melanoma detection. These vector-based fuzzy logic techniques can be extended to other image analysis problems involving multiple colors or color shades.

  18. Airborne Wide Area Imager for Wildfire Mapping and Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An autonomous airborne imaging system for earth science research, disaster response, and fire detection is proposed. The primary goal is to improve information to...

  19. Airborne Wide Area Imager for Wildfire Mapping and Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An advanced airborne imaging system for fire detection/mapping is proposed. The goal of the project is to improve control and management of wildfires in order to...

  20. Objective image analysis of the meibomian gland area

    OpenAIRE

    Arita, Reiko; Suehiro, Jun; Haraguchi, Tsuyoshi; Shirakawa, Rika; Tokoro, Hideaki; Amano, Shiro

    2013-01-01

    Aims To evaluate objectively the meibomian gland area using newly developed software for non-invasive meibography. Methods Eighty eyelids of 42 patients without meibomian gland loss (meiboscore=0), 105 eyelids of 57 patients with loss of less than one-third total meibomian gland area (meiboscore=1), 13 eyelids of 11 patients with between one-third and two-thirds loss of meibomian gland area (meiboscore=2) and 20 eyelids of 14 patients with two-thirds loss of meibomian gland area (meiboscore=3...

  1. Effects and Design of i-GaN and p-GaN Layer Thickness on The Back-illuminated and Front-illuminated GaN p-i-n Ultraviolet Photodetectors%背照射和正照射p-i-n结构GaN紫外探测器的i-GaN和p-GaN厚度设计

    Institute of Scientific and Technical Information of China (English)

    周梅; 李春燕; 赵德刚

    2015-01-01

    The effects of i-GaN and p-GaN layer thickness on the spectral response of back-illumi-nated and front-illuminated GaN p-i-n structure ultraviolet photodetectors were investigated by theory calculation. For the back-illuminated p-i-n photodetectors, the device quantum efficiency can be im-proved by both suitably decreasing the thickness of i-GaN layer and increasing the thickness of p-GaN layer, and the Ohmic contact property of p-GaN has not obvious influence on the device respon-sivity. The quantum efficiency of photodetector can be improved by reducing the background carrier concentration of i-GaN layer. The results are different for the front-illuminated p-i-n photodetectors. it is found that the device quantum efficiency can be improved by both properly increasing the thick-ness of i-GaN layer and decreasing the thickness of p-GaN layer, and the excellent Ohmic contact property of p-GaN is very important for the front-illuminated p-i-n hotodector. The opposite design method of i-GaN and p-GaN layer for the two photodetectors are mainly attributed to the different en-ergy band and photon absorption.%研究了i-GaN和p-GaN厚度对背照射和正照射p-i-n结构GaN紫外探测器响应光谱的影响。模拟计算发现:对于背照射结构,适当地减小i-GaN厚度有利于提高探测器的响应,降低i-GaN层的本底载流子浓度也有利于提高探测器的响应;p-GaN的欧姆接触特性好坏对探测器的响应影响不大,适当地增加p-GaN厚度可以改善探测器性能。而正照射结构则不同,i-GaN厚度对探测器的响应度影响不大,但欧姆接触特性差将严重降低探测器的响应,适当地减小p-GaN厚度可以大幅度改善探测器的响应特性。能带结构和入射光吸收的差别导致了正照射和背照射探测器结构中i层和p层厚度的选择和设计不同。

  2. Crystallographic extraction and averaging of data from small image areas

    NARCIS (Netherlands)

    Perkins, GA; Downing, KH; Glaeser, RM

    1995-01-01

    The accuracy of structure factor phases determined from electron microscope images is determined mainly by the level of statistical significance, which is limited by the low level of allowed electron exposure and by the number of identical unit cells that can be averaged. It is shown here that Fouri

  3. STEREOLOGICAL ESTIMATION OF SURFACE AREA FROM DIGITAL IMAGES

    Directory of Open Access Journals (Sweden)

    Johanna Ziegel

    2011-05-01

    Full Text Available A sampling design of local stereology is combined with a method from digital stereology to yield a novel estimator of surface area based on counts of configurations observed in a digitization of an isotropic 2- dimensional slice with thickness s. As a tool, a result of the second author and J. Rataj on infinitesimal increase of volumes of morphological transforms is refined and used. The proposed surface area estimator is asymptotically unbiased in the case of sets contained in the ball centred at the origin with radius s and in the case of balls centred at the origin with unknown radius. For general shapes bounds for the asymptotic expected relative worst case error are given. A simulation example is discussed for surface area estimation based on 2×2×2-configurations.

  4. Stereological estimation of surface area from digital images

    DEFF Research Database (Denmark)

    Ziegel, Johanna; Kiderlen, Markus

    2010-01-01

    A sampling design of local stereology is combined with a method from digital stereology to yield a novel estimator of surface area based on counts of configurations observed in a digitization of an isotropic 2- dimensional slice with thickness s. As a tool, a result of the second author and J....... Rataj on infinitesimal increase of volumes of morphological transforms is refined and used. The proposed surface area estimator is asymptotically unbiased in the case of sets contained in the ball centred at the origin with radius s and in the case of balls centred at the origin with unknown radius...

  5. Multispectral imaging of papyri: area segregation by evaluation of their spectral signature correlation

    Science.gov (United States)

    Kovalchuk, Alexander

    2009-10-01

    Multispectral imaging technology was applied to deteriorated ancient manuscripts. Monochrome images were registered at twelve wavelengths. An image processing algorithm that utilises relative spectral intensity distribution for the areas of the surface (rather than absolute values of intensity of the reflected light) was evaluated. It was found that the areas in a cubed MSI image representing ink and papyrus were separable due to their distinctive spectral signatures. The developed technique for enhancing the contrast of the inscriptions was shown to work effectively over a large range of lightness for both ink and papyrus surface.

  6. Image Fault Area Detection Algorithm Based on Visual Perception

    Directory of Open Access Journals (Sweden)

    Peng-Lu

    2011-02-01

    Full Text Available If the natural scenes decomposed by basic ICA which simulates visual perception then the arrangement in space of its basis functions are in disorder. This result is contradicted with physiological mechanisms of vision. So, a new compute model is proposed to simulate two important mechanisms of vision which are visual cortex receptive field topology construct and synchronous oscillation among neuron group. To solve the problem of train image fault detection, a novel algorithm was proposed based on above compute model. The experiment results show that, the algorithm can increase fault detection rate effectively compared with traditional methods which absence of above two important mechanisms of vision.

  7. ANALYZING SPECTRAL CHARACTERISTICS OF SHADOW AREA FROM ADS-40 HIGH RADIOMETRIC RESOLUTION AERIAL IMAGES

    Directory of Open Access Journals (Sweden)

    Y.-T. Hsieh

    2016-06-01

    Full Text Available The shadows in optical remote sensing images are regarded as image nuisances in numerous applications. The classification and interpretation of shadow area in a remote sensing image are a challenge, because of the reduction or total loss of spectral information in those areas. In recent years, airborne multispectral aerial image devices have been developed 12-bit or higher radiometric resolution data, including Leica ADS-40, Intergraph DMC. The increased radiometric resolution of digital imagery provides more radiometric details of potential use in classification or interpretation of land cover of shadow areas. Therefore, the objectives of this study are to analyze the spectral properties of the land cover in the shadow areas by ADS-40 high radiometric resolution aerial images, and to investigate the spectral and vegetation index differences between the various shadow and non-shadow land covers. According to research findings of spectral analysis of ADS-40 image: (i The DN values in shadow area are much lower than in nonshadow area; (ii DN values received from shadowed areas that will also be affected by different land cover, and it shows the possibility of land cover property retrieval as in nonshadow area; (iii The DN values received from shadowed regions decrease in the visible band from short to long wavelengths due to scattering; (iv The shadow area NIR of vegetation category also shows a strong reflection; (v Generally, vegetation indexes (NDVI still have utility to classify the vegetation and non-vegetation in shadow area. The spectral data of high radiometric resolution images (ADS-40 is potential for the extract land cover information of shadow areas.

  8. Application of image quality metamerism to investigate gold color area in cultural property

    Science.gov (United States)

    Miyata, Kimiyoshi; Tsumura, Norimichi

    2013-01-01

    A concept of image quality metamerism as an expansion of conventional metamerism defined in color science is introduced, and it is applied to segment similar color areas in a cultural property. The image quality metamerism can unify different image quality attributes based on an index showing the degree of image quality metamerism proposed. As a basic research step, the index is consisted of color and texture information and examined to investigate a cultural property. The property investigated is a pair of folding screen paintings that depict the thriving city of Kyoto designated as a nationally important cultural property in Japan. Gold-colored areas painted by using high granularity colorants compared with other color areas are evaluated based on the image quality metamerism index locally, then the index is visualized as a map showing the possibility of the image quality metamer to the reference pixel set in the same image. This visualization means a segmentation of areas where color is similar but texture is different. The experimental result showed that the proposed method was effective to show areas of gold color areas in the property.

  9. Large area CCD image sensors for space astronomy

    Science.gov (United States)

    Schwarzschild, M.

    1979-01-01

    The Defense Advanced Research Projects Agency (DARPA) has a substantial program to develop a 2200 x 2200 pixel CCD (Charge Coupled Device) mosaic array made up of 400 individual CCD's, 110 x 110 pixels square. This type of image sensor appeared to have application in space and ground-based astronomy. Under this grant a CCD television camera system was built which was capable of operating an array of 4 CCD's to explore the suitability of the CCD's to explore the suitability of the CCD for astronomical applications. Two individual packaged CCD's were received and evaluated. Evaluation of the basic characteristics of the best individual chips was encouraging, but the manufacturer found that their yield in manufacturing this design is two low to supply sufficient CDD's for the DARPA mosaic array. The potential utility of large mosaic arrays in astronomy is still substantial and continued monitoring of the manufacturers progress in the coming year is recommended.

  10. Large area CCD image sensors for scientific applications

    Science.gov (United States)

    Blouke, M. M.; Heidtmann, D. L.; Corrie, B.; Lust, M. L.; Janesick, J. R.

    1985-01-01

    The designs of the 512 x 512 pixel and 2048 x 2048 pixel CCD sensors developed for scientific imaging are described. Both sensors are manufactured using the three phase, three level polysilicon gate technology, and the architecture of the chips is series-parallel-series. The components of the two different on-chip amplifiers are examined. The sensors are thinned and operated in the back side illumination mode to ensure the highest quantum efficiency. The performances of a number of front side illuminated devices and two thinned rear illuminated chips are evaluated. It is observed that the sensors equal or exceed their proposed charge transfer efficiency of 0.99999, the noise level of 2 e- and 20 e- at 50 kp/s, the quantum efficiency of 40 percent at 400 microns and 70 percent at 700 microns, and of the well capacity of greater than 500 ke-/pixel.

  11. ADAPTIVE RECONSTRUCTION TECHNIQUE FOR THE LOST INFORMATION OF THE RECTANGULAR IMAGE AREA

    Institute of Scientific and Technical Information of China (English)

    Shi Rong; Li Xiaofeng; Li Zaiming

    2004-01-01

    The adaptive reconstruction for the lost information of the rectangular image area is very important for the robust transmission and restoration of the image. In this paper, a new reconstruction method based on the Discrete Cosine Transform (DCT) domain has been put forward. According to the low pass character of the human visual system and the energy distribution of the DCT coefficients on the rectangular boundary, the DCT coefficients of the rectangular image area are adaptively selected and recovered. After the Inverse Discrete Cosine Transform (IDCT), the lost information of the rectangular image area can be reconstructed. The experiments have demonstrated that the subjective and objective qualities of the reconstructed images are enhanced greatly than before.

  12. Automated Detection of Contaminated Radar Image Pixels in Mountain Areas

    Institute of Scientific and Technical Information of China (English)

    LIU Liping; Qin XU; Pengfei ZHANG; Shun LIU

    2008-01-01

    In mountain areas,radar observations are often contaminated(1)by echoes from high-speed moving vehicles and(2)by point-wise ground clutter under either normal propagation(NP)or anomalous propa-gation(AP)conditions.Level II data are collected from KMTX(Salt Lake City,Utah)radar to analyze these two types of contamination in the mountain area around the Great Salt Lake.Human experts provide the"ground truth"for possible contamination of either type on each individual pixel.Common features are then extracted for contaminated pixels of each type.For example,pixels contaminated by echoes from high-speed moving vehicles are characterized by large radial velocity and spectrum width.Echoes from a moving train tend to have larger velocity and reflectivity but smaller spectrum width than those from moving vehicles on highways.These contaminated pixels are only seen in areas of large terrain gradient(in the radial direction along the radar beam).The same is true for the second type of contamination-point-wise ground clutters.Six quality control(QC)parameters are selected to quantify the extracted features.Histograms are computed for each QC parameter and grouped for contaminated pixels of each type and also for non-contaminated pixels.Based on the computed histograms,a fuzzy logical algorithm is developed for automated detection of contaminated pixels.The algorithm is tested with KMTX radar data under different(clear and rainy)weather conditions.

  13. A Compact, Wide Area Surveillance 3D Imaging LIDAR Providing UAS Sense and Avoid Capabilities Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Eye safe 3D Imaging LIDARS when combined with advanced very high sensitivity, large format receivers can provide a robust wide area search capability in a very...

  14. Somatotopical relationships between cortical activity and reflex areas in reflexology: A functional magnetic resonance imaging study

    OpenAIRE

    Nakamaru, Tomomi; MIURA, NAOKI; Fukushima, Ai; Kawashima, Ryuta

    2008-01-01

    We examined the somatotopical relationship between cortical activity and sensory stimulation of reflex areas in reflexology using functional magnetic resonance imaging. Three reflex areas on the left foot, relating to the eye, shoulder, and small intestine were stimulated during the experiment. A statistical analysis showed that reflexological stimulation of the foot reflex areas corresponding to the eye, shoulder, and small intestine activated not only the somatosensory areas corresponding t...

  15. Representative and Diverse Image Set Gathering for Geographic Area and its Surrounding Region

    Directory of Open Access Journals (Sweden)

    Sonali B. Ulape

    2014-06-01

    Full Text Available Geo-tagging is becoming famous in today’s era of web 2.0 technologies. Geo-tagging is a concept in which we are adding information about location to the image. In proposed approach such geo-tagged images are used for making visual summary. Generally, visual summary of geographic location provides images of dominate location and ignore surrounding areas of that location which are potentially valuable. Multiple images of the same location suppress other places close to the dominant location and can be visited. In this proposed approach automatic visual summary of geographic area and its surrounding location is generated. For this community contributed images and their associated metadata are extracted from popular social websites such as Flickr [11]. Proposed approach generate visual summary which contains representative and diverse image set of given geographic location and its surrounding areas. For automatic generation of visual summary four layer graph of images and its associated metadata is formed. Proposed edge weight calculation method in this system is novel. With the help of random walk with restarts representative and diverse image set is selected which is visual summary of the given geographic location. Such visual summary can motivate a person to visit nearby areas of given geographic location.

  16. Myocardial Infarction Area Quantification using High-Resolution SPECT Images in Rats

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luciano Fonseca Lemos de [Divisão de Cardiologia, Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Mejia, Jorge [Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, SP (Brazil); Carvalho, Eduardo Elias Vieira de; Lataro, Renata Maria; Frassetto, Sarita Nasbine [Divisão de Cardiologia, Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Fazan, Rubens Jr.; Salgado, Hélio Cesar [Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Galvis-Alonso, Orfa Yineth [Faculdade de Medicina de São José do Rio Preto, São José do Rio Preto, SP (Brazil); Simões, Marcus Vinícius, E-mail: msimoes@fmrp.usp.br [Divisão de Cardiologia, Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2013-07-15

    Imaging techniques enable in vivo sequential assessment of the morphology and function of animal organs in experimental models. We developed a device for high-resolution single photon emission computed tomography (SPECT) imaging based on an adapted pinhole collimator. To determine the accuracy of this system for quantification of myocardial infarct area in rats. Thirteen male Wistar rats (250 g) underwent experimental myocardial infarction by occlusion of the left coronary artery. After 4 weeks, SPECT images were acquired 1.5 hours after intravenous injection of 555 MBq of 99mTc-Sestamibi. The tomographic reconstruction was performed by using specially developed software based on the Maximum Likelihood algorithm. The analysis of the data included the correlation between the area of perfusion defects detected by scintigraphy and extent of myocardial fibrosis assessed by histology. The images showed a high target organ/background ratio with adequate visualization of the left ventricular walls and cavity. All animals presenting infarction areas were correctly identified by the perfusion images. There was no difference of the infarct area as measured by SPECT (21.1 ± 21.2%) and by histology (21.7 ± 22.0%; p=0.45). There was a strong correlation between individual values of the area of infarction measured by these two methods. The developed system presented adequate spatial resolution and high accuracy for the detection and quantification of myocardial infarction areas, consisting in a low cost and versatile option for high-resolution SPECT imaging of small rodents.

  17. Use of dust storm observations on satellite images to identify areas vulnerable to severe wind erosion

    Science.gov (United States)

    Breed, C.S.; McCauley, J.F.

    1986-01-01

    Blowing dust is symptomatic of severe wind erosion and deterioration of soils in areas undergoing dessication and/or devegetation. Dust plumes on satellite images can commonly be traced to sources in marginally arable semiarid areas where protective lag gravels or vegetation have been removed and soils are dry, as demonstrated for the Portales Valley, New Mexico. Images from Landsat and manned orbiters such as Skylab and the Space Shuttle are useful for illustrating the regional relations of airborne dust plumes to source areas. Geostationary satellites such as GOES are useful in tracking the time-histories of episodic dust storms. These events sometimes go unrecognized by weather observers and are the precursors of long-term land degradation trends. In areas where soil maps and meteorological data are inadequate, satellite images provide a means for identifying problem areas where measures are needed to control or mitigate wind erosion. ?? 1986 D. Reidel Publishing Company.

  18. Digitized archive of the Kodaikanal images: Representative results of solar cycle variation from sunspot area determination

    CERN Document Server

    Ravindra, B; Amareswari, K; Priyal, M; Nazia, A A; Banerjee, D

    2012-01-01

    Photographic images are valuable data resources for studying long term changes in the solar magnetic field and its influence on the Earth's climate and weather. We digitized more than 100 years of white light images stored in photographic plates and films that are available at Kodaikanal observatory starting from 1904. The digitized images were calibrated for relative plate density and aligned in such a way that the solar north is in upward direction. A semi-automated sunspot detection technique was used to identify the sunspots on the digitized images. In addition to describing the calibration procedure and availability of the data, we here present preliminary results on the sunspot area measurements and their variation with time. The results show that the white-light images have a uniform spatial resolution throughout the 90 years of observations. However, the contrast of the images decreases from 1968 onwards. The images are circular and do not show any major geometrical distortions. The measured monthly a...

  19. No-Reference Image Quality Assessment for ZY3 Imagery in Urban Areas Using Statistical Model

    Science.gov (United States)

    Zhang, Y.; Cui, W. H.; Yang, F.; Wu, Z. C.

    2016-06-01

    More and more high-spatial resolution satellite images are produced with the improvement of satellite technology. However, the quality of images is not always satisfactory for application. Due to the impact of complicated atmospheric conditions and complex radiation transmission process in imaging process the images often suffer deterioration. In order to assess the quality of remote sensing images over urban areas, we proposed a general purpose image quality assessment methods based on feature extraction and machine learning. We use two types of features in multi scales. One is from the shape of histogram the other is from the natural scene statistics based on Generalized Gaussian distribution (GGD). A 20-D feature vector for each scale is extracted and is assumed to capture the RS image quality degradation characteristics. We use SVM to learn to predict image quality scores from these features. In order to do the evaluation, we construct a median scale dataset for training and testing with subjects taking part in to give the human opinions of degraded images. We use ZY3 satellite images over Wuhan area (a city in China) to conduct experiments. Experimental results show the correlation of the predicted scores and the subjective perceptions.

  20. Large area 3-D optical coherence tomography imaging of lumpectomy specimens for radiation treatment planning

    Science.gov (United States)

    Wang, Cuihuan; Kim, Leonard; Barnard, Nicola; Khan, Atif; Pierce, Mark C.

    2016-02-01

    Our long term goal is to develop a high-resolution imaging method for comprehensive assessment of tissue removed during lumpectomy procedures. By identifying regions of high-grade disease within the excised specimen, we aim to develop patient-specific post-operative radiation treatment regimens. We have assembled a benchtop spectral-domain optical coherence tomography (SD-OCT) system with 1320 nm center wavelength. Automated beam scanning enables "sub-volumes" spanning 5 mm x 5 mm x 2 mm (500 A-lines x 500 B-scans x 2 mm in depth) to be collected in under 15 seconds. A motorized sample positioning stage enables multiple sub-volumes to be acquired across an entire tissue specimen. Sub-volumes are rendered from individual B-scans in 3D Slicer software and en face (XY) images are extracted at specific depths. These images are then tiled together using MosaicJ software to produce a large area en face view (up to 40 mm x 25 mm). After OCT imaging, specimens were sectioned and stained with HE, allowing comparison between OCT image features and disease markers on histopathology. This manuscript describes the technical aspects of image acquisition and reconstruction, and reports initial qualitative comparison between large area en face OCT images and HE stained tissue sections. Future goals include developing image reconstruction algorithms for mapping an entire sample, and registering OCT image volumes with clinical CT and MRI images for post-operative treatment planning.

  1. Application of multispectral imaging detects areas with neuronal myelin loss, without tissue labelling.

    Science.gov (United States)

    Vazgiouraki, Eleftheria; Papadakis, Vassilis M; Efstathopoulos, Paschalis; Lazaridis, Iakovos; Charalampopoulos, Ioannis; Fotakis, Costas; Gravanis, Achille

    2016-04-01

    The application of multispectral imaging to discriminate myelinated and demyelinated areas of neural tissue is herein presented. The method is applied through a custom-made, multispectral imaging monochromator, coupled to a commercially available microscope. In the present work, a series of spinal cord sections were analysed derived from mice with experimental autoimmune encephalomyelitis (EAE), an experimental model widely used to study multiple sclerosis (MS). The multispectral microscope allows imaging of local areas with loss of myelin without the need of tissue labelling. Imaging with the aforementioned method and system is compared in a parallel way with conventional methods (wide-field and confocal fluorescence microscopies). The diagnostic sensitivity of our method is 90.4% relative to the 'gold standard' method of immunofluorescence microscopy. The presented method offers a new platform for the possible future development of anin vivo, real-time, non-invasive, rapid imaging diagnostic tool of spinal cord myelin loss-derived pathologies. PMID:26510556

  2. Large-area imaging micro-well detectors for high-energy astrophysics

    CERN Document Server

    Deines-Jones, P; Hunter, S D; Jahoda, K; Owens, S M

    2002-01-01

    Micro-well detectors are pixelized imaging sensors that can be inexpensively fabricated in very large arrays. Owing to their intrinsic gain and operation at room temperature, they can be instrumented at very low power, per unit area, making them valuable for a variety of space-flight applications where wide-angle X-ray imaging or large-area particle tracking is required. For example, micro-well detectors have been chosen as the focal plane imager for Lobster-ISS, a proposed soft X-ray all-sky monitor. We have fabricated detectors which image X-rays with 200 mu m FWHM resolution at 3 keV. In agreement with other groups using similar geometries, we find nominal proportional counter energy resolution (20% at 6 keV in P-10), and stable operation at gas gains up to 30,000.

  3. Image-guided surgery and medical robotics in the cranial area

    OpenAIRE

    Widmann, G

    2007-01-01

    Surgery in the cranial area includes complex anatomic situations with high-risk structures and high demands for functional and aesthetic results. Conventional surgery requires that the surgeon transfers complex anatomic and surgical planning information, using spatial sense and experience. The surgical procedure depends entirely on the manual skills of the operator. The development of image-guided surgery provides new revolutionary opportunities by integrating presurgical 3D imaging and intra...

  4. a Systematic Comparison of Direct and Image-Based Georeferencing in Challenging Urban Areas

    Science.gov (United States)

    Cavegn, S.; Nebiker, S.; Haala, N.

    2016-06-01

    Image-based mobile mapping systems enable an efficient acquisition of georeferenced image sequences, which can be used for geo-data capture in subsequent steps. In order to provide accurate measurements in a given reference frame while e.g. aiming at high fidelity 3D urban models, high quality georeferencing of the captured multi-view image sequences is required. Moreover, sub-pixel accurate orientations of these highly redundant image sequences are needed in order to optimally perform steps like dense multi-image matching as a prerequisite for 3D point cloud and mesh generation. While direct georeferencing of image-based mobile mapping data performs well in open areas, poor GNSS coverage in urban canyons aggravates fulfilling these high accuracy requirements, even with high-grade inertial navigation equipment. Hence, we conducted comprehensive investigations aiming at assessing the quality of directly georeferenced sensor orientations as well as the expected improvement by image-based georeferencing in a challenging urban environment. Our study repeatedly delivered mean trajectory deviations of up to 80 cm. By performing image-based georeferencing using bundle adjustment for a limited set of cameras and a limited number of ground control points, mean check point residuals could be lowered from approx. 40 cm to 4 cm. Furthermore, we showed that largely automated image-based georeferencing is capable of detecting and compensating discontinuities in directly georeferenced trajectories.

  5. Light microscopic image analysis system to quantify immunoreactive terminal area apposed to nerve cells

    Science.gov (United States)

    Wu, L. C.; D'Amelio, F.; Fox, R. A.; Polyakov, I.; Daunton, N. G.

    1997-01-01

    The present report describes a desktop computer-based method for the quantitative assessment of the area occupied by immunoreactive terminals in close apposition to nerve cells in relation to the perimeter of the cell soma. This method is based on Fast Fourier Transform (FFT) routines incorporated in NIH-Image public domain software. Pyramidal cells of layer V of the somatosensory cortex outlined by GABA immunolabeled terminals were chosen for our analysis. A Leitz Diaplan light microscope was employed for the visualization of the sections. A Sierra Scientific Model 4030 CCD camera was used to capture the images into a Macintosh Centris 650 computer. After preprocessing, filtering was performed on the power spectrum in the frequency domain produced by the FFT operation. An inverse FFT with filter procedure was employed to restore the images to the spatial domain. Pasting of the original image to the transformed one using a Boolean logic operation called 'AND'ing produced an image with the terminals enhanced. This procedure allowed the creation of a binary image using a well-defined threshold of 128. Thus, the terminal area appears in black against a white background. This methodology provides an objective means of measurement of area by counting the total number of pixels occupied by immunoreactive terminals in light microscopic sections in which the difficulties of labeling intensity, size, shape and numerical density of terminals are avoided.

  6. Portable digital electronic radiography system with a solid-state area-imaging detector

    CERN Document Server

    Sawicka, B D; Sonnenburg, K

    1999-01-01

    A digital system for radiographic inspection was constructed in a portable version suitable for field use. The system uses typical film radiography sources, including sup 6 sup 0 Co, sup 1 sup 9 sup 2 1r and X-ray generators. Radiographic images are formed using an area-imaging scintillating detector coupled to a charge-coupled device camera and a portable industrial computer. Compared to film radiography, this technology offers imaging without wet-film processing, shorter exposure times, larger dynamic range, and digital imaging that permits compact archiving, easy data access and mathematical image processing to improve sensitivity. System performance is illustrated for typical applications, i.e., for radiographing valves and pipes. Using ' sup 1 sup 9 sup 2 Ir, the system works well on smaller water-filled valves and pipes; larger valves have to be drained. Work is under way to address this problem.

  7. Urban-area extraction from polarimetric SAR image using combination of target decomposition and orientation angle

    Science.gov (United States)

    Zou, Bin; Lu, Da; Wu, Zhilu; Qiao, Zhijun G.

    2016-05-01

    The results of model-based target decomposition are the main features used to discriminate urban and non-urban area in polarimetric synthetic aperture radar (PolSAR) application. Traditional urban-area extraction methods based on modelbased target decomposition usually misclassified ground-trunk structure as urban-area or misclassified rotated urbanarea as forest. This paper introduces another feature named orientation angle to improve urban-area extraction scheme for the accurate mapping in urban by PolSAR image. The proposed method takes randomness of orientation angle into account for restriction of urban area first and, subsequently, implements rotation angle to improve results that oriented urban areas are recognized as double-bounce objects from volume scattering. ESAR L-band PolSAR data of the Oberpfaffenhofen Test Site Area was used to validate the proposed algorithm.

  8. Image-based diagnosis of alzheimer-type dementia. Measurements of hippocampal and ventricular areas in MR images

    International Nuclear Information System (INIS)

    We studied the possibility of objective diagnosis of Alzheimer-type dementia through radiological findings by evaluating cerebral and hippocampal atrophy in magnetic resonance images of patients with dementia. A statistically significant difference was seen in the hippocampus area index (HAI) and the ventricle area index (VAI) of healthy elderly individuals. Discriminant analysis with these two indexes demonstrated a sensitivity of 90.2% and a specificity of 81.8%, with an overall accuracy of 87.7%. Multiple discriminant analysis with VAI and HAI by stage of dementia showed an overall accuracy of 61.6% for discrimination of four stages. These results indicate that quantitative magnetic resonance imaging measurements can be used as an objective diagnostic technique for Alzheimer-type dementia. (author)

  9. Study on land use changes of the coal mining area based on TM image

    Institute of Scientific and Technical Information of China (English)

    WU Wen-bo; YAO Jing; KANG Ting-jun

    2008-01-01

    Based on the two temporal TM images of 1995 and 2001 of one coal mining area, analyzed the variety information of the coal mining area. Relative registration were done with the two images firstly, then cut out the study area for experimental data, classified the coal mining area using supervised classification in ERDAS, the coal mining area will be divided into five categories as water body, agricultural land, construction land, coal mining area and other land. Make land use change matrix, the result shows that in the six years of 1995 to 2001, the change of the utilize of the land is greatly, the main represent is showed as follows: the area of water body, agricultural land and coal mining land had continually increased, on the contrary, construction area and other decreased. The percentage speed of the construction land is the biggest, the value reach -1.08%. The main reasons is that with the exploitation of the coal mine and the reclaim of the land, the exploitation of the coal mining land make the agricultural land and construction area convert into coal mining land, on the other hand with the backfill of the subsided waterlogged land and the reclaim of the subsided land make the coal mining land convert into agricultural land.

  10. Filtering Techniques on Analysis of Archeology Areas Using RADARSAT Images: Case Study of Lembah Bujang, Malaysia

    Science.gov (United States)

    Norzailawati, M. N.; Akma, R. S.; Alias, A.; Zuraini, M. A.

    2016-06-01

    Speckle noise present in radar imagery caused by interaction of out -of-phase waves with a target, the objective of this paper is attempt to test filtering techniques consist of Lee, Frost and Gamma Map to identify a potential shrines area in Lembah Bujang using RADARSAT imageries. The multi-temporal images of RADARSAT for years 2003 and 2014 have been used filtering techniques in identifying potential shrines consist of have been used and tested to selected study areas with using processing software of ENVI 4.8 and ArcGIS 10.2. Based on mathematical morphology, the speckles in these images were reduced, once the reduction is achieved, the enhancement of archaeological sites is accomplished. The finding shows that Local Adaptive Filtering on GAMMA Map filter is the best techniques in identifying potential shrines areas at once as guidance to pursuing an area as official gazette historical site in Malaysia context.

  11. Detection of flooded urban areas in high resolution Synthetic Aperture Radar images using double scattering

    Science.gov (United States)

    Mason, D. C.; Giustarini, L.; Garcia-Pintado, J.; Cloke, H. L.

    2014-05-01

    Flooding is a particular hazard in urban areas worldwide due to the increased risks to life and property in these regions. Synthetic Aperture Radar (SAR) sensors are often used to image flooding because of their all-weather day-night capability, and now possess sufficient resolution to image urban flooding. The flood extents extracted from the images may be used for flood relief management and improved urban flood inundation modelling. A difficulty with using SAR for urban flood detection is that, due to its side-looking nature, substantial areas of urban ground surface may not be visible to the SAR due to radar layover and shadow caused by buildings and taller vegetation. This paper investigates whether urban flooding can be detected in layover regions (where flooding may not normally be apparent) using double scattering between the (possibly flooded) ground surface and the walls of adjacent buildings. The method estimates double scattering strengths using a SAR image in conjunction with a high resolution LiDAR (Light Detection and Ranging) height map of the urban area. A SAR simulator is applied to the LiDAR data to generate maps of layover and shadow, and estimate the positions of double scattering curves in the SAR image. Observations of double scattering strengths were compared to the predictions from an electromagnetic scattering model, for both the case of a single image containing flooding, and a change detection case in which the flooded image was compared to an un-flooded image of the same area acquired with the same radar parameters. The method proved successful in detecting double scattering due to flooding in the single-image case, for which flooded double scattering curves were detected with 100% classification accuracy (albeit using a small sample set) and un-flooded curves with 91% classification accuracy. The same measures of success were achieved using change detection between flooded and un-flooded images. Depending on the particular flooding

  12. Mapping Eroded Areas on Mountain Grassland with Terrestrial Photogrammetry and Object-Based Image Analysis

    Science.gov (United States)

    Mayr, Andreas; Rutzinger, Martin; Bremer, Magnus; Geitner, Clemens

    2016-06-01

    In the Alps as well as in other mountain regions steep grassland is frequently affected by shallow erosion. Often small landslides or snow movements displace the vegetation together with soil and/or unconsolidated material. This results in bare earth surface patches within the grass covered slope. Close-range and remote sensing techniques are promising for both mapping and monitoring these eroded areas. This is essential for a better geomorphological process understanding, to assess past and recent developments, and to plan mitigation measures. Recent developments in image matching techniques make it feasible to produce high resolution orthophotos and digital elevation models from terrestrial oblique images. In this paper we propose to delineate the boundary of eroded areas for selected scenes of a study area, using close-range photogrammetric data. Striving for an efficient, objective and reproducible workflow for this task, we developed an approach for automated classification of the scenes into the classes grass and eroded. We propose an object-based image analysis (OBIA) workflow which consists of image segmentation and automated threshold selection for classification using the Excess Green Vegetation Index (ExG). The automated workflow is tested with ten different scenes. Compared to a manual classification, grass and eroded areas are classified with an overall accuracy between 90.7% and 95.5%, depending on the scene. The methods proved to be insensitive to differences in illumination of the scenes and greenness of the grass. The proposed workflow reduces user interaction and is transferable to other study areas. We conclude that close-range photogrammetry is a valuable low-cost tool for mapping this type of eroded areas in the field with a high level of detail and quality. In future, the output will be used as ground truth for an area-wide mapping of eroded areas in coarser resolution aerial orthophotos acquired at the same time.

  13. MAPPING ERODED AREAS ON MOUNTAIN GRASSLAND WITH TERRESTRIAL PHOTOGRAMMETRY AND OBJECT-BASED IMAGE ANALYSIS

    Directory of Open Access Journals (Sweden)

    A. Mayr

    2016-06-01

    Full Text Available In the Alps as well as in other mountain regions steep grassland is frequently affected by shallow erosion. Often small landslides or snow movements displace the vegetation together with soil and/or unconsolidated material. This results in bare earth surface patches within the grass covered slope. Close-range and remote sensing techniques are promising for both mapping and monitoring these eroded areas. This is essential for a better geomorphological process understanding, to assess past and recent developments, and to plan mitigation measures. Recent developments in image matching techniques make it feasible to produce high resolution orthophotos and digital elevation models from terrestrial oblique images. In this paper we propose to delineate the boundary of eroded areas for selected scenes of a study area, using close-range photogrammetric data. Striving for an efficient, objective and reproducible workflow for this task, we developed an approach for automated classification of the scenes into the classes grass and eroded. We propose an object-based image analysis (OBIA workflow which consists of image segmentation and automated threshold selection for classification using the Excess Green Vegetation Index (ExG. The automated workflow is tested with ten different scenes. Compared to a manual classification, grass and eroded areas are classified with an overall accuracy between 90.7% and 95.5%, depending on the scene. The methods proved to be insensitive to differences in illumination of the scenes and greenness of the grass. The proposed workflow reduces user interaction and is transferable to other study areas. We conclude that close-range photogrammetry is a valuable low-cost tool for mapping this type of eroded areas in the field with a high level of detail and quality. In future, the output will be used as ground truth for an area-wide mapping of eroded areas in coarser resolution aerial orthophotos acquired at the same time.

  14. Performance of a Fieldable Large-Area, Coded-Aperture, Gamma Imager

    Energy Technology Data Exchange (ETDEWEB)

    Habte Ghebretatios, Frezghi [ORNL; Cunningham, Mark F [Lawrence Livermore National Laboratory (LLNL); Fabris, Lorenzo [ORNL; Ziock, Klaus-Peter [ORNL

    2007-01-01

    We recently developed a fieldable large-area, coded-aperture, gamma imager (the Large Area Imager - LAI). The instrument was developed to detect weak radiation sources in a fluctuating natural background. Ideally, the efficacy of the instrument is determined using receiver-operator statistics generated from measurement data in terms of probability of detection versus probability of false alarm. However, due to the impracticality of hiding many sources in public areas, it is difficult to measure the data required to generate receiver-operator characteristic (ROC) curves. Instead, we develop a high statistics "model source" from measurements of a real point source and then inject the model source into data collected from the world at large where, presumably, no source exists. In this paper we have applied this "source injection" technique to evaluate the performance of the LAI. We plotted ROC curves obtained for different source locations from the imager and for different source strengths when the source is injected at 50 m from the imager. The result shows that this prototype instrument provides excellent performance for a 1-mCi source at a distance of 50 m from the imager in a single pass at 25 mph.

  15. Single-grain Silicon Technology for Large Area X-ray Imaging

    OpenAIRE

    Arslan, A

    2015-01-01

    Digital flat panel X-ray imagers are currently using a-Si and poly-Si thin-film-transistors (TFTs). a-Si TFT permits the use of large area substrates, however, due to the amorphous nature, the carrier mobility is very low (

  16. Single-grain Silicon Technology for Large Area X-ray Imaging

    NARCIS (Netherlands)

    Arslan, A.

    2015-01-01

    Digital flat panel X-ray imagers are currently using a-Si and poly-Si thin-film-transistors (TFTs). a-Si TFT permits the use of large area substrates, however, due to the amorphous nature, the carrier mobility is very low (<1 cm2/Vs). Poly-Si TFT improves the mobility (~150 cm2/Vs) but due to random

  17. Determination of representative elementary areas for soil redoximorphic features by digital image processing

    Science.gov (United States)

    Photography has been a welcome tool in documenting and conveying qualitative soil information. When coupled with image analysis software, the usefulness of digital cameras can be increased to advance the field of micropedology. The determination of a Representative Elementary Area (REA) still rema...

  18. Measuring the Pain Area: An Intra- and Inter-Rater Reliability Study Using Image Analysis Software.

    Science.gov (United States)

    Dos Reis, Felipe Jose Jandre; de Barros E Silva, Veronica; de Lucena, Raphaela Nunes; Mendes Cardoso, Bruno Alexandre; Nogueira, Leandro Calazans

    2016-01-01

    Pain drawings have frequently been used for clinical information and research. The aim of this study was to investigate intra- and inter-rater reliability of area measurements performed on pain drawings. Our secondary objective was to verify the reliability when using computers with different screen sizes, both with and without mouse hardware. Pain drawings were completed by patients with chronic neck pain or neck-shoulder-arm pain. Four independent examiners participated in the study. Examiners A and B used the same computer with a 16-inch screen and wired mouse hardware. Examiner C used a notebook with a 16-inch screen and no mouse hardware, and Examiner D used a computer with an 11.6-inch screen and a wireless mouse. Image measurements were obtained using GIMP and NIH ImageJ computer programs. The length of all the images was measured using GIMP software to a set scale in ImageJ. Thus, each marked area was encircled and the total surface area (cm(2) ) was calculated for each pain drawing measurement. A total of 117 areas were identified and 52 pain drawings were analyzed. The intrarater reliability between all examiners was high (ICC = 0.989). The inter-rater reliability was also high. No significant differences were observed when using different screen sizes or when using or not using the mouse hardware. This suggests that the precision of these measurements is acceptable for the use of this method as a measurement tool in clinical practice and research. PMID:25490926

  19. Photon counting pixel and array in amorphous silicon technology for large area digital medical imaging applications

    Science.gov (United States)

    Yazdandoost, Mohammad Y.; Shin, Kyung W.; Safavian, Nader; Taghibakhsh, Farhad; Karim, Karim S.

    2010-04-01

    A single photon counting Voltage Controlled Oscillator (VCO) based pixel architecture in amorphous silicon (a-Si) technology is reported for large area digital medical imaging. The VCO converts X-ray generated input charge into an output oscillating frequency signal. Experimental results for an in-house fabricated VCO circuit in a-Si technology are presented and external readout circuits to extract the image information from the VCO's frequency output are discussed. These readout circuits can be optimized to reduce the fixed pattern noise and fringing effects in an imaging array containing many such VCO pixels. Noise estimations, stability simulations and measurements for the fabricated VCO are presented. The reported architecture is particularly promising for large area photon counting applications (e.g. low dose fluoroscopy, dental computed tomography (CT)) due to its very low input referred electronic noise, high sensitivity and ease of fabrication in low cost a-Si technology.

  20. Shadow detection improvement using spectral indices and morphological operators in high resolution images from urban areas

    Science.gov (United States)

    Azevedo, S. C.; Silva, E. A.; Pedrosa, M. M.

    2015-04-01

    While high-resolution remote sensing images have increased application possibilities for urban studies, the large number of shadow areas has created challenges to processing and extracting information from these images. Furthermore, shadows can reduce or omit information from the surface as well as degrading the visual quality of images. The pixels of shadows tend to have lower radiance response within the spectrum and are often confused with low reflectance targets. In this work, a shadow detection method was proposed using a morphological operator for dark pattern identification combined with spectral indices. The aims are to avoid misclassification in shadow identification through properties provided by them on color models and, therefore, to improve shadow detection accuracy. Experimental results were tested applying the panchromatic and multispectral band of WorldView-2 image from Sao Paulo city in Brazil, which is a complex urban environment composed by high objects like tall buildings causing large shadow areas. Black top-hat with area injunction was applied in PAN image and shadow identification performance has improved with index as Normalized Difference Vegetation Index (NDVI) and Normalized Saturation-Value Difference Index (NSDVI) ratio from HSV color space obtained from pansharpened multispectral WV-2 image. An increase in distinction between shadows and others objects was observed, which was tested for the completeness, correctness and quality measures computed, using a created manual shadow mask as reference. Therefore, this method can contribute to overcoming difficulties faced by other techniques that need shadow detection as a first necessary preprocessing step, like object recognition, image matching, 3D reconstruction, etc.

  1. Feature-based registration of historical aerial images by Area Minimization

    Science.gov (United States)

    Nagarajan, Sudhagar; Schenk, Toni

    2016-06-01

    The registration of historical images plays a significant role in assessing changes in land topography over time. By comparing historical aerial images with recent data, geometric changes that have taken place over the years can be quantified. However, the lack of ground control information and precise camera parameters has limited scientists' ability to reliably incorporate historical images into change detection studies. Other limitations include the methods of determining identical points between recent and historical images, which has proven to be a cumbersome task due to continuous land cover changes. Our research demonstrates a method of registering historical images using Time Invariant Line (TIL) features. TIL features are different representations of the same line features in multi-temporal data without explicit point-to-point or straight line-to-straight line correspondence. We successfully determined the exterior orientation of historical images by minimizing the area formed between corresponding TIL features in recent and historical images. We then tested the feasibility of the approach with synthetic and real data and analyzed the results. Based on our analysis, this method shows promise for long-term 3D change detection studies.

  2. ColonyArea: an ImageJ plugin to automatically quantify colony formation in clonogenic assays.

    Directory of Open Access Journals (Sweden)

    Camilo Guzmán

    Full Text Available The clonogenic or colony formation assay is a widely used method to study the number and size of cancer cell colonies that remain after irradiation or cytotoxic agent administration and serves as a measure for the anti-proliferative effect of these treatments. Alternatively, this assay is used to quantitate the transforming potential of cancer associated genes and chemical agents. Therefore, there is a need for a simplified and standardized analysis of colony formation assays for both routine laboratory use and for parallelized automated analysis. Here we describe the freely available ImageJ-plugin "ColonyArea", which is optimized for rapid and quantitative analysis of focus formation assays conducted in 6- to 24-well dishes. ColonyArea processes image data of multi-well dishes, by separating, concentrically cropping and background correcting well images individually, before colony formation is quantitated. Instead of counting the number of colonies, ColonyArea determines the percentage of area covered by crystal violet stained cell colonies, also taking the intensity of the staining and therefore cell density into account. We demonstrate that these parameters alone or in combination allow for robust quantification of IC50 values of the cytotoxic effect of two staurosporines, UCN-01 and staurosporine (STS on human glioblastoma cells (T98G. The relation between the potencies of the two compounds compared very well with that obtained from an absorbance based method to quantify colony growth and to published data. The ColonyArea ImageJ plugin provides a simple and efficient analysis routine to quantitate assay data of one of the most commonly used cellular assays. The bundle is freely available for download as supporting information. We expect that ColonyArea will be of broad utility for cancer biologists, as well as clinical radiation scientists.

  3. Mapping Deciduous Rubber Plantation Areas and Stand Ages with PALSAR and Landsat Images

    Directory of Open Access Journals (Sweden)

    Weili Kou

    2015-01-01

    Full Text Available Accurate and updated finer resolution maps of rubber plantations and stand ages are needed to understand and assess the impacts of rubber plantations on regional ecosystem processes. This study presented a simple method for mapping rubber plantation areas and their stand ages by integration of PALSAR 50-m mosaic images and multi-temporal Landsat TM/ETM+ images. The L-band PALSAR 50-m mosaic images were used to map forests (including both natural forests and rubber trees and non-forests. For those PALSAR-based forest pixels, we analyzed the multi-temporal Landsat TM/ETM+ images from 2000 to 2009. We first studied phenological signatures of deciduous rubber plantations (defoliation and foliation and natural forests through analysis of surface reflectance, Normal Difference Vegetation Index (NDVI, Enhanced Vegetation Index (EVI, and Land Surface Water Index (LSWI and generated a map of rubber plantations in 2009. We then analyzed phenological signatures of rubber plantations with different stand ages and generated a map, in 2009, of rubber plantation stand ages (≤5, 6–10, >10 years-old based on multi-temporal Landsat images. The resultant maps clearly illustrated how rubber plantations have expanded into the mountains in the study area over the years. The results in this study demonstrate the potential of integrating microwave (e.g., PALSAR and optical remote sensing in the characterization of rubber plantations and their expansion over time.

  4. Wide area 2D/3D imaging development, analysis and applications

    CERN Document Server

    Langmann, Benjamin

    2014-01-01

    Imaging technology is an important research area and it is widely utilized in a growing number of disciplines ranging from gaming, robotics and automation to medicine. In the last decade 3D imaging became popular mainly driven by the introduction of novel 3D cameras and measuring devices. These cameras are usually limited to indoor scenes with relatively low distances. Benjamin Langmann introduces medium and long-range 2D/3D cameras to overcome these limitations. He reports measurement results for these devices and studies their characteristic behavior. In order to facilitate the application o

  5. Estimation of leaf area index in cereal crops using red–green images

    DEFF Research Database (Denmark)

    Nielsen, Kristian Kirk; Andersen, Hans Jørgen; Thomsen, Anton;

    2009-01-01

    A new method for estimating the leaf area index (LAI) in cereal crops based on red–green images taken from above the crop canopy is introduced. The proposed method labels pixels into vegetation and soil classes using a combination of greenness and intensity derived from the red and green colour b....... Conclusions Acknowledgements Appendix. Modelling the correlation between greenness and brightness References   Fig. 1. Simulated image of a vegetation canopy (left), with distribution of pixel greenness and brightness (right). View Within Article...

  6. Unsupervised classification of saturated areas using a time series of remotely sensed images

    Directory of Open Access Journals (Sweden)

    D. A. DeAlwis

    2007-06-01

    Full Text Available The spatial distribution of saturated areas is an important consideration in numerous applications, such as water resource planning or sighting of management practices. However, in humid well vegetated climates where runoff is produced by saturation excess processes on hydrologically active areas (HAA the delineation of these areas can be difficult and time consuming. Much of the non-point source pollution in these watersheds originates from these HAAs. Thus, a technique that can simply and reliably predict these areas would be a powerful tool for scientists and watershed managers tasked with implementing practices to improve water quality. Remotely sensed data is a source of spatial information and could be used to identify HAAs, should a proper technique be developed. The objective of this study is to develop a methodology to determine the spatial variability of saturated areas using a temporal sequence of remotely sensed images. The Normalized Difference Water Index (NDWI was derived from medium resolution LANDSAT 7 ETM+ imagery collected over seven months in the Town Brook watershed in the Catskill Mountains of New York State and used to characterize the areas that were susceptible to saturation. We found that within a single landcover type, saturated areas were characterized by the soil surface water content when the vegetation was dormant and leaf water content of vegetation during the growing season. The resulting HAA map agreed well with both observed and spatially distributed computer simulated saturated areas. This methodology appears promising for delineating saturated areas in the landscape.

  7. An Adaptive Color Image Visible Watermark Algorithm Supporting for Interested Area and its Application System Based on Internet

    Directory of Open Access Journals (Sweden)

    Hu Guoqing

    2015-01-01

    Full Text Available This paper presents an interested area visible watermark algorithm for digital color image based on internet. By converting color image from RGB to HSI and using the original image information to obtain the watermark coefficient, the algorithm embeds watermark on the spatial domain and selects the interested area by clicking on the picture. By visiting the site (http://dgdz.ccee.cqu.edu.cn/watermark/watermarkb.aspx and uploading the original image and watermark image, the color image with the visible watermark can be gained on web. Experimental results show that the algorithm has only a little influence on the original image and the image of watermark is clearly visible. It is very suitable for obvious identification of the copyright from digital image through Internet.

  8. Prediction of lean and fat composition in swine carcasses from ham area measurements with image analysis.

    Science.gov (United States)

    Jia, Jiancheng; Schinckel, Allan P; Forrest, John C; Chen, Way; Wagner, Jeffrey R

    2010-06-01

    Video images of ham cross-sections were recorded from 71 pork carcasses (ranging in weight from 72 to 119kg). Three sets of prediction equations were developed to estimate pork carcass lean and fat composition from video image analysis (VIA) of ham cross-sectional area measurements, 10th rib back fat depth (TENFAT) and hot carcass weight (HCKg). Carcass data of dissected lean and fat in the four primal cuts (ham, loin, Boston button and picnic shoulder) were used as dependent variables in establishing regression equations. The first set of equations combined VIA ham measurements and total ham weight (HTKg). Regression models containing the single variable HTKg times ham percentage lean area (Vol. 1) or HTKg times ham percentage fat area (Vol. 2) accounted for 88% and 68% of the variation in total carcass lean weight (CLKg) and total carcass fat weight (CFKg) from the right side of each carcass, respectively. The second set of equations combined VIA ham measurements and TENFAT (cm). Multiple regression models involving TENFAT, Vol. 1, and Vol. 2 accounted for 91% and 90% of the variation in CLKg and CFKg. The third set of equations used VIA ham measurements, TENFAT and HCKg. Carcass lean weight was best predicted by HCKg, TENFAT, and ham lean area (HLA) (R(2)=.92). Carcass fat weight was best predicted by HCKg, TENFAT, and Vol. 2 (R(2)=.91). Overall correlations showed a high association between Vol. 1 and CLKg (r=.94, PVol. 2 and CFKg (r=.83, P<.0001). Ham lean area was related to CLKg (r=.74, P<.0001) and ham fat area to CFKg (r=.81, P<.0001). The results of this study indicated video image analysis of ham cross-section slices combined with backfat depth at the 10th rib can be used for accurate estimation of total carcass lean or fat composition.

  9. Implementation of large area CMOS image sensor module using the precision align inspection

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Wook; Kim, Toung Ju; Ryu, Cheol Woo [Radiation Imaging Technology Center, JBTP, Iksan (Korea, Republic of); Lee, Kyung Yong; Kim, Jin Soo [Nano Sol-Tech INC., Iksan (Korea, Republic of); Kim, Myung Soo; Cho, Gyu Seong [Dept. of Nuclear and Quantum Engineering, KAIST, Daejeon (Korea, Republic of)

    2014-12-15

    This paper describes a large area CMOS image sensor module Implementation using the precision align inspection program. This work is needed because wafer cutting system does not always have high precision. The program check more than 8 point of sensor edges and align sensors with moving table. The size of a 2×1 butted CMOS image sensor module which except for the size of PCB is 170 mm×170 mm. And the pixel size is 55 μm×55 μm and the number of pixels is 3,072×3,072. The gap between the two CMOS image sensor module was arranged in less than one pixel size.

  10. High-resolution texture imaging with hard synchrotron radiation in the moving area detector technique

    CERN Document Server

    Wcislak, L; Klein, H; Garbe, U; Schneider, J R

    2003-01-01

    The orientation distribution of crystallites in polycrystalline materials (called texture) is usually measured by polycrystal X-ray diffraction by 'step-scanning' the sample in angular intervals in the order of 1 deg. This technique is not suited to fully exploit the low angular divergence of hard synchrotron radiation in the order of 'milliradian'. Hence, step-scanning was replaced by a continuous 'sweeping' technique using a continuously shifted area detector. In order to avoid overlapping from different reflections (hkl) a Bragg-angle slit was introduced. The 'moving-detector' technique can be applied to obtain images of orientation as well as of location distributions of crystallites in polycrystalline samples. It is suitable for imaging continuous 'orientation density' distribution functions as well as of 'grain-resolved' textures. The excellent features of high-energy synchrotron radiation combined with the moving area detector technique will be illustrated with several examples including very sharp def...

  11. Determination of Destructed and Infracted Forest Areas with Multi-temporal High Resolution Satellite Images

    Science.gov (United States)

    Seker, D. Z.; Unal, A.; Kaya, S.; Alganci, U.

    2015-12-01

    Migration from rural areas to city centers and their surroundings is an important problem of not only our country but also the countries that under development stage. This uncontrolled and huge amount of migration brings out urbanization and socio - economic problems. The demand on settling the industrial areas and commercial activities nearby the city centers results with a negative change in natural land cover on cities. Negative impacts of human induced activities on natural resources and land cover has been continuously increasing for decades. The main human activities that resulted with destruction and infraction of forest areas can be defined as mining activities, agricultural activities, industrial / commercial activities and urbanization. Temporal monitoring of the changes in spatial distribution of forest areas is significantly important for effective management and planning progress. Changes can occur as spatially large destructions or small infractions. Therefore there is a need for reliable, fast and accurate data sources. At this point, satellite images proved to be a good data source for determination of the land use /cover changes with their capability of monitoring large areas with reasonable temporal resolutions. Spectral information derived from images provides discrimination of land use/cover types from each other. Developments in remote sensing technology in the last decade improved the spatial resolution of satellites and high resolution images were started to be used to detect even small changes in the land surface. As being the megacity of Turkey, Istanbul has been facing a huge migration for the last 20 years and effects of urbanization and other human based activities over forest areas are significant. Main focus of this study is to determine the destructions and infractions in forest areas of Istanbul, Turkey with 2.5m resolution SPOT 5 multi-temporal satellite imagery. Analysis was mainly constructed on threshold based classification of

  12. Delineating potential epileptogenic areas utilizing resting functional magnetic resonance imaging (fMRI) in epilepsy patients.

    Science.gov (United States)

    Pizarro, Ricardo; Nair, Veena; Meier, Timothy; Holdsworth, Ryan; Tunnell, Evelyn; Rutecki, Paul; Sillay, Karl; Meyerand, Mary E; Prabhakaran, Vivek

    2016-08-01

    Seizure localization includes neuroimaging like electroencephalogram, and magnetic resonance imaging (MRI) with limited ability to characterize the epileptogenic network. Temporal clustering analysis (TCA) characterizes epileptogenic network congruent with interictal epileptiform discharges by clustering together voxels with transient signals. We generated epileptogenic areas for 12 of 13 epilepsy patients with TCA, congruent with different areas of seizure onset. Resting functional MRI (fMRI) scans are noninvasive, and can be acquired quickly, in patients with different levels of severity and function. Analyzing resting fMRI data using TCA is quick and can complement clinical methods to characterize the epileptogenic network. PMID:27362339

  13. Application of Enhanced-2D-CWT in Topographic Images for Mapping Landslide Risk Areas

    CERN Document Server

    Valenzuela, V V Vermehren; de Oliveira, H M

    2015-01-01

    There has been lately a number of catastrophic events of landslides and mudslides in the mountainous region of Rio de Janeiro, Brazil. Those were caused by intense rain in localities where there was unplanned occupation of slopes of hills and mountains. Thus, it became imperative creating an inventory of landslide risk areas in densely populated cities. This work presents a way of demarcating risk areas by using the bidimensional Continuous Wavelet Transform (2D-CWT) applied to high resolution topographic images of the mountainous region of Rio de Janeiro.

  14. Normal development of brainstem in childhood. Measurement of the area on mid-sagittal MR imaging

    International Nuclear Information System (INIS)

    Developmental abnormality of brainstem is shown in pediatric patients with mental retardation, autism, periventricular leukomalacia, neurodegenerative disease, and so on. Our purpose here is to clarify the normal developmental pattern of the brainstem. We measured the area of tectum, midbrain tegmentum, pons, basis pontis and pontine tegmentum on mid-sagittal MR images in 111 children (newborn to 20 year old). Different growth patterns were shown in all parts of the brainstem. Tectum showed a subtle increase in area from the newborn to adult period, while midbrain tegmentum and pontine tegmenturn showed a mild and gradual increase in area. Pons and pontine tegmentum showed a rapid and prominent increase in area from newborn to infant period and gradual increase in area until the adult period. These different growth patterns seemed to be consistent with differences in the myelination cycles of the neuronal fibers, maturation of the nuclei and proliferation of glial cells in each part of the brainstem. Mid-sagittal MR imaging of the head is accurate and reproducible and is used conveniently in routine head MR study, making it very useful for the diagnosis of many central nervous diseases and anomalies. We believe that this new milestone provided in this study will be helpful in distinguishing normal children from those that have neurodegenerative disorders. (author)

  15. Digital Terrain Model Generation By Using Area Based Image Matching Techniques

    OpenAIRE

    KARALAR, Fikret; Uysal, Murat; VARLIK, Abdullah; CAN, Zekai Cevdet

    2010-01-01

    Recently, Photogrammetry is the one of the most suitable methods to be Digital Terrain Model (DTM) generation for large areas accurately and actually. Automatic DTM generation is fundamental functional module of Digital Photogrammetry. In fact, many of Digital Photogrammetric systems offer that function and must take into consideration that be significant for a great number of users. One of the most advantages the Digital Photogrammetry have been formed a regular DTM by means of image matchin...

  16. Estimation of the sugar cane cultivated area from LANDSAT images using the two phase sampling method

    Science.gov (United States)

    Parada, N. D. J. (Principal Investigator); Cappelletti, C. A.; Mendonca, F. J.; Lee, D. C. L.; Shimabukuro, Y. E.

    1982-01-01

    A two phase sampling method and the optimal sampling segment dimensions for the estimation of sugar cane cultivated area were developed. This technique employs visual interpretations of LANDSAT images and panchromatic aerial photographs considered as the ground truth. The estimates, as a mean value of 100 simulated samples, represent 99.3% of the true value with a CV of approximately 1%; the relative efficiency of the two phase design was 157% when compared with a one phase aerial photographs sample.

  17. A gas scintillation counter with imaging optics and large area UV-detector

    Energy Technology Data Exchange (ETDEWEB)

    Nickles, J. E-mail: nickles@hsb.uni-frankfurt.de; Braeuning, H.; Braeuning-Demian, A.; Dangendorf, V.; Breskin, A.; Chechik, R.; Rauschnabel, K.; Schmidt-Boecking, H

    2002-01-21

    We report on the improvements in the position sensitive readout of a xenon-filled gas scintillation proportional counter. Using an imaging optic for UV-light in the region of 170 nm, the position resolution could be improved by more than 30%. In addition, we have obtained first encouraging results for the use of the recently developed gas electron multiplier together with a CsI-photocathode as a large area UV-detector system.

  18. A gas scintillation counter with imaging optics and large area UV-detector

    CERN Document Server

    Nickles, J; Bräuning-Demian, A; Breskin, Amos; Chechik, R; Dangendorf, V; Rauschnabel, K; Schmidt-Böcking, H

    2002-01-01

    We report on the improvements in the position sensitive readout of a xenon-filled gas scintillation proportional counter. Using an imaging optic for UV-light in the region of 170 nm, the position resolution could be improved by more than 30%. In addition, we have obtained first encouraging results for the use of the recently developed gas electron multiplier together with a CsI-photocathode as a large area UV-detector system.

  19. Novel large-area MIS-type x-ray image sensor for digital radiography

    Science.gov (United States)

    Kameshima, Toshio; Kaifu, Noriyuki; Takami, Eiichi; Morishita, Masakazu; Yamazaki, Tatsuya

    1998-07-01

    We have developed a brand new, large-area X-ray image sensor for Digital Radiography System (DRS). The sensor utilizes a thin film transistor (TFT)/metal insulator semiconductor (MIS)-type photoelectric converter array made from hydrogenated amorphous silicon (a-Si:H). The sensor has 2688 X 2688 pixels at a pitch of 160 micrometer. The active area is 17 inch X 17 inch. The sensor utilizes scintillator coupled to the array. The light generated by X-rays is detected by the MIS-type photoelectric converters, and the resultant signals are scanned out by switching the TFTs. The a-Si TFT/MIS-type photoelectric converter array is characterized by high signal to noise ratio (SNR) and simple fabrication process. We will describe the principle and the performance of the sensor. In addition, we will present some X-ray images of a human subject obtained with this sensor. Dynamic range of the sensor covers most of the exposure range for radiography. SNR is limited almost only by the X-ray photon noise. MTF is sufficient for digital chest radiography. X-ray images have good contrast. The experimental results and obtained images show that the brand new sensor has great advantages for replacing X-ray film. The simple fabrication process of the sensor promises high productivity and low cost of DRS.

  20. Objects Grouping for Segmentation of Roads Network in High Resolution Images of Urban Areas

    Science.gov (United States)

    Maboudi, M.; Amini, J.; Hahn, M.

    2016-06-01

    Updated road databases are required for many purposes such as urban planning, disaster management, car navigation, route planning, traffic management and emergency handling. In the last decade, the improvement in spatial resolution of VHR civilian satellite sensors - as the main source of large scale mapping applications - was so considerable that GSD has become finer than size of common urban objects of interest such as building, trees and road parts. This technological advancement pushed the development of "Object-based Image Analysis (OBIA)" as an alternative to pixel-based image analysis methods. Segmentation as one of the main stages of OBIA provides the image objects on which most of the following processes will be applied. Therefore, the success of an OBIA approach is strongly affected by the segmentation quality. In this paper, we propose a purpose-dependent refinement strategy in order to group road segments in urban areas using maximal similarity based region merging. For investigations with the proposed method, we use high resolution images of some urban sites. The promising results suggest that the proposed approach is applicable in grouping of road segments in urban areas.

  1. a New Algorithm for Void Filling in a Dsm from Stereo Satellite Images in Urban Areas

    Science.gov (United States)

    Gharib Bafghi, Z.; Tian, J.; d'Angelo, P.; Reinartz, P.

    2016-06-01

    Digital Surface Models (DSM) derived from stereo-pair satellite images are the main sources for many Geo-Informatics applications like 3D change detection, object classification and recognition. However since occlusion especially in urban scenes result in some deficiencies in the stereo matching phase, these DSMs contain some voids. In order to fill the voids a range of algorithms have been proposed, mainly including interpolation alone or along with auxiliary DSM. In this paper an algorithm for void filling in DSM from stereo satellite images has been developed. Unlike common previous approaches we didn't use any external DSM to fill the voids. Our proposed algorithm uses only the original images and the unfilled DSM itself. First a neighborhood around every void in the unfilled DSM and its corresponding area in multispectral image is defined. Then it is analysed to extract both spectral and geometric texture and accordingly to assign labels to each cell in the voids. This step contains three phases comprising shadow detection, height thresholding and image segmentation. Thus every cell in void has a label and is filled by the median value of its co-labelled neighbors. The results for datasets from WorldView-2 and IKONOS are shown and discussed.

  2. Classification of poplar stand areas by high-resolution satellite images

    Directory of Open Access Journals (Sweden)

    Grignetti A

    2009-09-01

    Full Text Available This work concerns the classification of different crown cover classes of Poplar stands, using high spatial resolution images (Ikonos and Quickbird satellites, in order to provide poplar monitoring. The test sites are two agricultural areas, located in the alluvial plain of northern Italy, close to Alessandria. In order to enhance spectral differences among classes, textural and high-pass filters were applied and vegetation indices (ratio, difference and normalized difference were processed. Images were then classified by means of an object-oriented approach which include a segmentation process followed by the application of a Standard Nearest Neighbor classifier on different data sets of spectral images (mean and standard deviation images and shape indices (shape, compactness. The data sets were defined using the Feature Space Optimization tool available in the Definiens®Developer7 software. From a set of attributes, this tool selects the best combination that produces the largest separability among the classes. The shape of the polygons matched the agricultural plots and the classification results were compared with the reference map defined by means of aerial photo interpretation and ground surveys. New poplar classes were defined in order to improve classification results. The accuracy values obtained were satisfactory (close to 73% for Ikonos and 82% for Quickbird images and they constitute a basis for automated recognition of poplar plantations and for updating poplar stands assessments.

  3. Solid images generated from UAVs to analyze areas affected by rock falls

    Science.gov (United States)

    Giordan, Daniele; Manconi, Andrea; Allasia, Paolo; Baldo, Marco

    2015-04-01

    The study of rock fall affected areas is usually based on the recognition of principal joints families and the localization of potential instable sectors. This requires the acquisition of field data, although as the areas are barely accessible and field inspections are often very dangerous. For this reason, remote sensing systems can be considered as suitable alternative. Recently, Unmanned Aerial Vehicles (UAVs) have been proposed as platform to acquire the necessary information. Indeed, mini UAVs (in particular in the multi-rotors configuration) provide versatility for the acquisition from different points of view a large number of high resolution optical images, which can be used to generate high resolution digital models relevant to the study area. By considering the recent development of powerful user-friendly software and algorithms to process images acquired from UAVs, there is now a need to establish robust methodologies and best-practice guidelines for correct use of 3D models generated in the context of rock fall scenarios. In this work, we show how multi-rotor UAVs can be used to survey areas by rock fall during real emergency contexts. We present two examples of application located in northwestern Italy: the San Germano rock fall (Piemonte region) and the Moneglia rock fall (Liguria region). We acquired data from both terrestrial LiDAR and UAV, in order to compare digital elevation models generated with different remote sensing approaches. We evaluate the volume of the rock falls, identify the areas potentially unstable, and recognize the main joints families. The use on is not so developed but probably this approach can be considered the better solution for a structural investigation of large rock walls. We propose a methodology that jointly considers the Structure from Motion (SfM) approach for the generation of 3D solid images, and a geotechnical analysis for the identification of joint families and potential failure planes.

  4. MUNSELL COLOR ANALYSIS OF LANDSAT COLOR-RATIO-COMPOSITE IMAGES OF LIMONITIC AREAS IN SOUTHWEST NEW MEXICO.

    Science.gov (United States)

    Kruse, Fred A.

    1984-01-01

    Green areas on Landsat 4/5 - 4/6 - 6/7 (red - blue - green) color-ratio-composite (CRC) images represent limonite on the ground. Color variation on such images was analyzed to determine the causes of the color differences within and between the green areas. Digital transformation of the CRC data into the modified cylindrical Munsell color coordinates - hue, value, and saturation - was used to correlate image color characteristics with properties of surficial materials. The amount of limonite visible to the sensor is the primary cause of color differences in green areas on the CRCs. Vegetation density is a secondary cause of color variation of green areas on Landsat CRC images. Digital color analysis of Landsat CRC images can be used to map unknown areas. Color variations of green pixels allows discrimination among limonitic bedrock, nonlimonitic bedrock, nonlimonitic alluvium, and limonitic alluvium.

  5. Functional Imaging of Broca’s Area in Native Persian Speakers: An fMRI Study

    Directory of Open Access Journals (Sweden)

    A Mahdavi

    2008-12-01

    Full Text Available Background/Objective: The problem of localization of speech associated cortices using noninvasive methods has been of utmost importance in many neuroimaging studies, but the results are difficult to resolve for specific neurosurgical applications. In this study, we used fMRI to delineate language-related brain activation patterns with emphasis on the Broca's area during the execution of two Persian language tasks."nPatients and Methods: The subjects comprised of nine healthy right-handed men who participated voluntarily in this study. They performed two consequent fMRI paradigms namely; "Word Production" and "Reverse Word Reading". The fMRI data were collected and analyzed. Then, functional images were registered to anatomical images using FSL software. The laterality indices were also calculated in regions of interest with different threshold levels."nResults: The results indicate that Broca's area, as the classical language-production center, was robustly activated while performing these two tasks. In eight out of nine subjects, the left hemisphere dominancy and Broca's area activation were observed and in one case activation was prominent in the homologous area in the right hemisphere."nConclusion: Similar pattern of cortical activation during Persian word production and Anglophone languages such as English was revealed. fMRI is a valuable means for brain mapping in language studies.

  6. Fast signal transfer in a large-area X-ray CMOS image sensor

    International Nuclear Information System (INIS)

    For 2-d X-ray imaging, such as mammography and non-destructive test, a sensor should have a large-area because the sensor for typical X-ray beams cannot use optical lens system. To make a large-area 2-d X-ray image sensor using crystal Si, a technique of tiling unit CMOS image sensors into 2 × 2 or 2 × 3 array can be used. In a unit CMOS image sensor made of most common 8-inch Si wafers, the signal line can be up to ∼ 180 mm long. Then its parasitic capacitance is up to ∼ 25 pF and its resistance is up to ∼ 51 kΩ (0.18 μm, 1P3M process). This long signal line may enlarge the row time up to ∼ 50 μsec in case of the signal from the top row pixels to the readout amplifiers located at the bottom of the sensor chip. The output signal pulse is typically characterized by three components in sequence; a charging time (a rising part), a reading time and a discharging time (a falling part). Among these, the discharging time is the longest, and it limits the speed or the frame rate of the X-ray imager. We proposed a forced discharging method which uses a bypass transistor in parallel with the current source of the column signal line. A chip for testing the idea was fabricated by a 0.18 μm process. A active pixel sensor with three transistors and a 3-π RC model of the long line were simulated together. The test results showed that the turning on-and-off of the proposed bypass transistor only during the discharging time could dramatically reduce the discharging time from ∼ 50 μsec to ∼ 2 μsec, which is the physically minimum time determined by the long metal line capacitance

  7. Vocim analysis of laryngeal images: is breathiness related to the glottic area?

    Science.gov (United States)

    Jeannon, J P; Carding, P N; Wilson, J A

    1998-08-01

    The aim of this study was to determine the relationship between glottic space and breathy voice. Using a new computerized method of analysing the glottic area of video images with the Vocim computer system, 16 patients with a vocal cord palsy and 31 with non-organic dysphonia were examined. The quality of the breathy voice was assessed and correlated with the size of the glottic space during phonation. There was a positive (r = 0.70) correlation between glottic area and breathy voice in vocal cord palsy. There was no correlation (r = 0.002) in non-organic dysphonia. Therefore in this study population, for vocal cord palsy, glottic area is the dominant feature in determining voice quality. This relationship is not maintained in non-organic dysphonia.

  8. Laterality of brain areas associated with arithmetic calculations revealed by functional magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yun-ting; ZHANG Quan; ZHANG Jing; LI Wei

    2005-01-01

    Background Asymmetry of bilateral cerebral function, i.e. laterality, is an important phenomenon in many brain actions: arithmetic calculation may be one of these phenomena. In this study, first, laterality of brain areas associated with arithmetic calculations was revealed by functional magnetic resonance imaging (fMRI). Second, the relationship among laterality, handedness, and types of arithmetic task was assessed. Third, we postulate possible reasons for laterality.Methods Using a block-designed experiment, twenty-five right-handed and seven left-handed healthy volunteers carried out simple calculations, complex calculations and proximity judgments. T1WI and GRE-EPI fMRI were performed with a GE 1.5T whole body MRI scanner. Statistical parametric mapping (SPM99) was used to process data and localize functional areas. Numbers of activated voxels were recorded to calculate laterality index for evaluating the laterality of functional brain areas.Results For both groups, the activation of functional areas in the frontal lobe showed a tendency towards the nonpredominant hand side, but the functional areas in the inferior parietal lobule had left laterality. During simple and complex calculations, the laterality indices of the prefrontal cortex and premotor area were higher in the right-handed group than that in the left-handed group, whereas the laterality of the inferior parietal lobule had no such significant difference. In both groups, when the difficulty of the task increased, the laterality of the prefrontal cortex, premotor area, and inferior parietal lobule decreased, but the laterality of posterior part of the inferior frontal gyrus increased.Conclusions The laterality of the functional brain areas associated with arithmetic calculations can be detected with fMRI. The laterality of the functional areas was related to handedness and task difficulty.

  9. Characterization of potential mineralization in Afghanistan: four permissive areas identified using imaging spectroscopy data

    Science.gov (United States)

    King, Trude V.V.; Berger, Byron R.; Johnson, Michaela R.

    2014-01-01

    As part of the U.S. Geological Survey and Department of Defense Task Force for Business and Stability Operations natural resources revitalization activities in Afghanistan, four permissive areas for mineralization, Bamyan 1, Farah 1, Ghazni 1, and Ghazni 2, have been identified using imaging spectroscopy data. To support economic development, the areas of potential mineralization were selected on the occurrence of selected mineral assemblages mapped using the HyMap™ data (kaolinite, jarosite, hydrated silica, chlorite, epidote, iron-bearing carbonate, buddingtonite, dickite, and alunite) that may be indicative of past mineralization processes in areas with limited or no previous mineral resource studies. Approximately 30 sites were initially determined to be candidates for areas of potential mineralization. Additional criteria and material used to refine the selection and prioritization process included existing geologic maps, Landsat Thematic Mapper data, and published literature. The HyMapTM data were interpreted in the context of the regional geologic and tectonic setting and used the presence of alteration mineral assemblages to identify areas with the potential for undiscovered mineral resources. Further field-sampling, mapping, and supporting geochemical analyses are necessary to fully substantiate and verify the specific deposit types in the four areas of potential mineralization.

  10. Mapping Pollution Plumes in Areas Impacted by Hurricane Katrina With Imaging Spectroscopy

    Science.gov (United States)

    Swayze, G. A.; Furlong, E. T.; Livo, K. E.

    2007-12-01

    New Orleans endured flooding on a massive scale subsequent to Hurricane Katrina in August of 2005. Contaminant plumes were noticeable in satellite images of the city in the days following flooding. Many of these plumes were caused by oil, gasoline, and diesel that leaked from inundated vehicles, gas stations, and refineries. News reports also suggested that the flood waters were contaminated with sewage from breached pipes. Effluent plumes such as these pose a potential health hazard to humans and wildlife in the aftermath of hurricanes and potentially from other catastrophic events (e.g., earthquakes, shipping accidents, chemical spills, and terrorist attacks). While the extent of effluent plumes can be gauged with synthetic aperture radar and broad- band visible-infrared images (Rykhus, 2005) (e.g., Radarsat and Landsat ETM+) the composition of the plumes could not be determined. These instruments lack the spectral resolution necessary to do chemical identification. Imaging spectroscopy may help solve this problem. Over 60 flight lines of NASA Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were collected over New Orleans, the Mississippi Delta, and the Gulf Coast from one to two weeks after Katrina while the contaminated water was being pumped out of flooded areas. These data provide a unique opportunity to test if imaging spectrometer data can be used to identify the chemistry of these flood-related plumes. Many chemicals have unique spectral signatures in the ultraviolet to near-infrared range (0.2 - 2.5 microns) that can be used as fingerprints for their identification. We are particularly interested in detecting thin films of oil, gasoline, diesel, and raw sewage suspended on or in water. If these materials can be successfully differentiated in the lab then we will use spectral-shape matching algorithms to look for their spectral signatures in the AVIRIS data collected over New Orleans and other areas impacted by Katrina. If imaging spectroscopy

  11. A Full Parallel Event Driven Readout Technique for Area Array SPAD FLIM Image Sensors

    Directory of Open Access Journals (Sweden)

    Kaiming Nie

    2016-01-01

    Full Text Available This paper presents a full parallel event driven readout method which is implemented in an area array single-photon avalanche diode (SPAD image sensor for high-speed fluorescence lifetime imaging microscopy (FLIM. The sensor only records and reads out effective time and position information by adopting full parallel event driven readout method, aiming at reducing the amount of data. The image sensor includes four 8 × 8 pixel arrays. In each array, four time-to-digital converters (TDCs are used to quantize the time of photons’ arrival, and two address record modules are used to record the column and row information. In this work, Monte Carlo simulations were performed in Matlab in terms of the pile-up effect induced by the readout method. The sensor’s resolution is 16 × 16. The time resolution of TDCs is 97.6 ps and the quantization range is 100 ns. The readout frame rate is 10 Mfps, and the maximum imaging frame rate is 100 fps. The chip’s output bandwidth is 720 MHz with an average power of 15 mW. The lifetime resolvability range is 5–20 ns, and the average error of estimated fluorescence lifetimes is below 1% by employing CMM to estimate lifetimes.

  12. A Full Parallel Event Driven Readout Technique for Area Array SPAD FLIM Image Sensors.

    Science.gov (United States)

    Nie, Kaiming; Wang, Xinlei; Qiao, Jun; Xu, Jiangtao

    2016-01-01

    This paper presents a full parallel event driven readout method which is implemented in an area array single-photon avalanche diode (SPAD) image sensor for high-speed fluorescence lifetime imaging microscopy (FLIM). The sensor only records and reads out effective time and position information by adopting full parallel event driven readout method, aiming at reducing the amount of data. The image sensor includes four 8 × 8 pixel arrays. In each array, four time-to-digital converters (TDCs) are used to quantize the time of photons' arrival, and two address record modules are used to record the column and row information. In this work, Monte Carlo simulations were performed in Matlab in terms of the pile-up effect induced by the readout method. The sensor's resolution is 16 × 16. The time resolution of TDCs is 97.6 ps and the quantization range is 100 ns. The readout frame rate is 10 Mfps, and the maximum imaging frame rate is 100 fps. The chip's output bandwidth is 720 MHz with an average power of 15 mW. The lifetime resolvability range is 5-20 ns, and the average error of estimated fluorescence lifetimes is below 1% by employing CMM to estimate lifetimes. PMID:26828490

  13. Age estimation using pulp/tooth area ratio: A digital image analysis

    Directory of Open Access Journals (Sweden)

    Sasidhar Singaraju

    2009-01-01

    Full Text Available Age is one of the essential factors in establishing the identity of the person. Estimation of the human age is a procedure adopted by anthropologists, archeologists, and forensic scientists. Inspection of radiographs and subsequent comparison with radiographic images, in charts yield ′maturity scores′ that help us to assess the age of an individual. Alternative approaches based on digitalization of panoramic radiographs and their computerized storage have recently become available that exploit image analysis to obtain nondestructive metric measurements of both pulp chambers and teeth, which can be used to assess the age of an individual. The purpose of the present study was to present a method for assessing the chronological age based on the relationship between age and measurement of the pulp/tooth area ratio on single-rooted teeth, using orthopantomographs and a computer-aided drafting program AutoCAD 2000.

  14. Evaluation of impact-affected areas of glass fibre thermoplastic composites from thermographic images

    Science.gov (United States)

    Boccardi, S.; Carlomagno, G. M.; Simeoli, G.; Russo, P.; Meola, C.

    2016-07-01

    The usefulness of an infrared imaging device, in terms of both acting as a mechanism for surface thermal monitoring when a specimen is being impacted and as a non-destructive evaluation technique, has already been proved. Nevertheless, past investigation has focused on mainly thermoset-matrix composites with little attention towards thermoplastic ones. Conversely, these thermoplastic composites are becoming ever more attractive to the aeronautical sector. Their main advantage lies in the possibility of modifying their interface strength by adjusting the composition of the matrix. However, for a proper exploitation of new materials it is necessary to detail their characterization. The purpose of the present paper is to focus on the use of infrared thermography (IRT) to gain information on the behaviour of thermoplastic composites under impact. In addition, attention is given to image processing algorithms with the aim of more effectively measuring the extension of the impact-affected area.4

  15. [Quantification of crop residue burned areas based on burning indices using Landsat 8 image].

    Science.gov (United States)

    Ma, Jian-hang; Song, Kai-shar; Wen, Zhi-dan; Shao, Tian-tian; Li, Bo-nan; Qi, Cai

    2015-11-01

    Crop residue burning leads to atmospheric pollution and is an enormous waste of crop residue resource. Crop residue burning can be monitored timely in large regions as the fire points can be recognized through remotely sensed image via thermal infrared bands. However, the area, the detailed distribution pattern and especially the severity of the burning areas cannot be derived only by the thermal remote sensing approach. The burning index, which was calculated with two or more spectral bands at where the burned and unburned areas have distinct spectral characteristics, is widely used in the forest fire investigation. However its potential application for crop residue burning evaluation has not been explored. With two Landsat 8 images that cover a part of the Songnen Plain, three burning indices, i.e., the normalized burned ratio (NBR), the normalized burned ratio incorporating the thermal band (NBRT), and the burned area index (BAI), were used to classify the crop residue burned and unburned areas. The overall classification accuracies were 91.9%, 92.3%, and 87.8%, respectively. The correlation analysis between the indices and the crop residue coverage indicated that the NBR and NBRT were positively correlated with the crop residue coverage (R2 = 0.73 and 0.64, respectively) with linear regression models, while the BAI was exponentially correlated with the crop residue coverage (R2 = 0.68). The results indicated that the use of burning indices in crop residue burning monitoring could quantify crop residue burning severity and provide valuable data for evaluating atmospheric pollution.

  16. [Quantification of crop residue burned areas based on burning indices using Landsat 8 image].

    Science.gov (United States)

    Ma, Jian-hang; Song, Kai-shar; Wen, Zhi-dan; Shao, Tian-tian; Li, Bo-nan; Qi, Cai

    2015-11-01

    Crop residue burning leads to atmospheric pollution and is an enormous waste of crop residue resource. Crop residue burning can be monitored timely in large regions as the fire points can be recognized through remotely sensed image via thermal infrared bands. However, the area, the detailed distribution pattern and especially the severity of the burning areas cannot be derived only by the thermal remote sensing approach. The burning index, which was calculated with two or more spectral bands at where the burned and unburned areas have distinct spectral characteristics, is widely used in the forest fire investigation. However its potential application for crop residue burning evaluation has not been explored. With two Landsat 8 images that cover a part of the Songnen Plain, three burning indices, i.e., the normalized burned ratio (NBR), the normalized burned ratio incorporating the thermal band (NBRT), and the burned area index (BAI), were used to classify the crop residue burned and unburned areas. The overall classification accuracies were 91.9%, 92.3%, and 87.8%, respectively. The correlation analysis between the indices and the crop residue coverage indicated that the NBR and NBRT were positively correlated with the crop residue coverage (R2 = 0.73 and 0.64, respectively) with linear regression models, while the BAI was exponentially correlated with the crop residue coverage (R2 = 0.68). The results indicated that the use of burning indices in crop residue burning monitoring could quantify crop residue burning severity and provide valuable data for evaluating atmospheric pollution. PMID:26915202

  17. Mapping cortical areas associated with Chinese word processing using functiona l magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    马林; 唐一源; 王岩; 李德军; 翁旭初; 张武田; 庄建程; 胡小平

    2003-01-01

    Objectives To identify the cortical areas engaged during Chinese word processing using func tional magnetic resonance imaging (fMRI) and to examine the reliability and repr oducibility of fMRI for localization of functional areas in the human brain.Methods FMRI data were collected on 8 young, right-handed, native Chinese speakers duri ng performance of Chinese synonym and homophone judgment tasks on two different clinical MRI systems (1.5 T GE Signa Horizon and 1.5 T Siemens Vision). A cro ss correlation analysis was used to statistically generate the activation map.Results Broca's area, Wernicke's area, bilateral extrastriate, and ventral tempo ral cortex were significantly activated during both the synonym and homophone activities. There was essentially no difference between results acquired on two different MRI systems.Conclusions FMRI can be used for localizing cortical areas critical to Chinese language proc essing in the human brain. The results are reliable and well reproducible acros s different clinical MRI systems.

  18. Two designs for image digital processing applications in the nuclear area using ImaWin

    International Nuclear Information System (INIS)

    In this work two designs of image processing systems of low cost for the nuclear area are presented. They have the advantage of the adaptability given by the ImaWin software and the connection with Internet, applied to digitalisation in research and development fields. The first design is the development of a digitalisation system for inspection and study of fuel plate radiographs for test reactors, while the second one describes the specification and design of an intelligent system of intrusion signals continuous inspection and administrative control of fissile material deposits. (author)

  19. Estimation of leaf area index in cereal crops using red-green images

    DEFF Research Database (Denmark)

    Kirk, Kristian; Andersen, Hans Jørgen; Thomsen, Anton G;

    2009-01-01

    A new method for estimating the leaf area index (LAI) in cereal crops based on red-green images taken from above the crop canopy is introduced. The proposed method labels pixels into vegetation and soil classes using a combination of greenness and intensity derived from the red and green colour...... bands. The intensity feature is included to give better separation of the classes, especially under difficult sunny conditions. The performance of the method was investigated in three field experiments during the period 2004-2006. LAI was estimated using gap fraction inversion with an exponential gap...

  20. Trends in the development of large area photon detectors for Cherenkov light imaging applications

    CERN Document Server

    Nappi, E

    2003-01-01

    Since the successful operations of hi-tech devices at OMEGA, DELPHI and SLD, the technique of Cherenkov light imaging has gone through an impressive and fruitful evolution driven by the conception of novel large area photon detectors. The well-assessed potentialities of thin CsI films, employed as reflective photoconverters in gas counters operated at atmospheric pressure, will be compared with the promising features of hybrid and multianode vacuum photomultipliers. Recently proposed single-photon gaseous detectors based on GEMs will also be reviewed.

  1. Area-Efficient Low Power CMOS Image Sensor Readout Circuit with Fixed Pattern Noise Cancellation

    Institute of Scientific and Technical Information of China (English)

    赵士彬; 姚素英; 聂凯明; 徐江涛

    2010-01-01

    A low cost of die area and power consumption CMOS image sensor readout circuit with fixed pattern noise(FPN) cancellation is proposed.By using only one coupling capacitor and switch in the double FPN cancelling correlative double sampling(CDS),pixel FPN is cancelled and column FPN is stored and eliminated by the sampleand-hold operation of digitally programmable gain amplifier(DPGA).The bandwidth balance technology based on operational amplifier(op-amp) sharing is also introduced to decrease the power dissi...

  2. Measuring the area of tear film break-up by image analysis software

    Science.gov (United States)

    Pena-Verdeal, Hugo; García-Resúa, Carlos; Ramos, Lucía.; Mosquera, Antonio; Yebra-Pimentel, Eva; Giráldez, María. Jesús

    2013-11-01

    Tear film breakup time (BUT) test only examines the first break in the tear film, but subsequent tear film events are not monitored. We present a method of measuring the area of breakup after the appearance of the first breakup by using open source software. Furthermore, the speed of the rupture was determined. 84 subjects participated in the study. 2 μl volume of 2% sodium fluorescein was instilled using a micropipette. The subject was seated behind a slit-lamp using a cobalt blue filter together with a Wratten 12 yellow filter. Then, the tear film was recorded by a camera attached to the slit lamp. 4 frames of each video was extracted, the first rupture (BUT_0), breakup after 1 second (BUT_1), rupture after 2 seconds (BUT_2) and breakup before the last blink (BUT_F). Open source software of measurement based on Java (NIH ImageJ) was used to measure the number of pixels in areas of breakup. These areas were divided by the area of exposed cornea to obtain the percentage of ruptures. Instantaneous breakup speed was calculated for second 1 as the difference between BUT_1 - BUT_0, whereas instant speed for second 2 was BUT_2 - BUT_1. Mean area of breakup obtained was: BUT_0 = 0.26%, BUT_1 = 0.48%, BUT_2 = 0.79% and BUT_F = 1.61%. Break speed was 0.22 area/sec for second 1 and 0.31 area/sec for second 2, showing a statistical difference between them (p = 0.007). Post BUT analysis may be easily monitoring with the aid of this software.

  3. Ground Deformation Monitoring in Qingdao Coastal Areas by Time-Series Terrasar-X Images

    Science.gov (United States)

    Hou, A. Y.; Qiao, X.; Li, D.

    2016-06-01

    As a new generation of high resolution and short revisit period of radar satellite, TerraSAR-X is not only able to meet the requirements of monitoring large scale surface subsidence, but also make it possible to monitor the small deformation of the short period. This articles takes the coastal areas of the west coast of Qingdao as the research object. With Small baselines subsets interferometry synthetic aperture radar (SBASI), this paper obtained the period the average annual rate of change from the time series analysis of TerraSAR-X data from April 2015 to October 2014.In order to enrich the historical deformation data of the study area, it analyse the time series of ALOS images from December 2010 to October 2008 with the same method. Finally,it analyse and demonstrate the experimental results.

  4. Representation of Block-Based Image Features in a Multi-Scale Framework for Built-Up Area Detection

    Directory of Open Access Journals (Sweden)

    Zhongwen Hu

    2016-02-01

    Full Text Available The accurate extraction and mapping of built-up areas play an important role in many social, economic, and environmental studies. In this paper, we propose a novel approach for built-up area detection from high spatial resolution remote sensing images, using a block-based multi-scale feature representation framework. First, an image is divided into small blocks, in which the spectral, textural, and structural features are extracted and represented using a multi-scale framework; a set of refined Harris corner points is then used to select blocks as training samples; finally, a built-up index image is obtained by minimizing the normalized spectral, textural, and structural distances to the training samples, and a built-up area map is obtained by thresholding the index image. Experiments confirm that the proposed approach is effective for high-resolution optical and synthetic aperture radar images, with different scenes and different spatial resolutions.

  5. How illumination and contrast affect the area measurement of small particles by digital imaging

    Science.gov (United States)

    Taylor, Robert A.; Godbey, Luther C.

    1992-02-01

    Images from conventional video systems are being digitized in computers for the analysis of small particles. The method was developed to automate particle counting and area measurements of dark trash particles in cotton. However, it can be applied to many similar area measurement problems. Because video output is linearly proportional to the amount of light reflected, the best spectral band for optimum particle discrimination should be centered at the wavelength of maximum difference in reflectance between particles and their surroundings. However, due to the distribution of the illumination energy and the distribution of the detector sensitivity, peak performance bands are shifted. Reflectance from cleaned cotton samples and trash particles were measured to define spectral contrast. Pixel intensity histograms form the video system are reported for simulated area reference samples (painted dots on panels) and for actual cotton samples to demonstrate the particle discrimination mechanism. particles from different parts of the cotton plant were used to demonstrate the importance of considering a particle's contrast in the area measurement.

  6. Magnetic resonance imaging of lacunar infarcts in the basal ganglionic area

    International Nuclear Information System (INIS)

    During the previous 2 years, 88 patients have been diagnosed as having lacunar infarcts in the basal ganglioa ( a total of 157 lesions) on magnetic resonance imaging (MRI):42 patients had a single lesion and 46 patients had multiple lesions (2 lesions in 25 patients, 3 lesions in 14, and 4 or more lesions in 7). Seventy-seven lesions (49%) were smaller than 5 mm in diameter, and the others ranged from 5 mm to 15 mm. According to the regional relations to the internal capsule, the lesions were classified as lateral (57 lesions), anterior (36), superior (34), posterior (26), and inferior (4). Lesions of posterior, anterior, superior, and inferior types were associated with severer hemisparetic state, an abnormally slow gait, a sensory disturbance of numbness, and a depressive state, respectively. Forty five lesions (28%) were asymptomatic. Cat scanning failed to deliniate 47 lesions (30%) that were detected on MRI. Twenty three lesions were both asymptomatic and undistinguished on CT, which consisted of the superior type (10), anteior type (7), lateral type (5), and posterior type (one). Twenty four lesions were symptomatic, but were undistinguished on CT, suggesting that MRI is superior to CT in detecting the lacunar infarcts in the basal ganglionic area. Lacunar infarcts in both acute and chronic stages tended to be larger on T2-weighted images than T1-weighted images. In 7 patients who had neither history of hypertension, diabetes mellitus, or cardiac emboli nor CT evidence, MRI was capable of detecting lacunar infarcts. (N.K.)

  7. Detection of Built-Up Areas Using Polarimetric Synthetic Aperture Radar Data and Hyperspectral Image

    Science.gov (United States)

    Bordbari, R.; Maghsoudi, Y.; Salehi, M.

    2015-12-01

    Polarimetric synthetic aperture radar (POLSAR) is an advantageous data for information extraction about objects and structures by using the wave scattering and polarization properties. Hyperspectral remote sensing exploits the fact that all materials reflect, absorb, and emit electromagnetic energy, at specific wavelengths, in distinctive patterns related to their molecular composition. As a result of their fine spectral resolution, Hyperspectral image (HIS) sensors provide a significant amount of information about the physical and chemical composition of the materials occupying the pixel surface. In target detection applications, the main objective is to search the pixels of an HSI data cube for the presence of a specific material (target). In this research, a hierarchical constrained energy minimization (hCEM) method using 5 different adjusting parameters has been used for target detection from hyperspectral data. Furthermore, to detect the built-up areas from POLSAR data, building objects discriminated from surrounding natural media presented on the scene using Freeman polarimetric target decomposition (PTD) and the correlation coefficient between co-pol and cross-pol channels. Also, target detection method has been implemented based on the different polarization basis for using the more information. Finally a majority voting method has been used for fusing the target maps. The polarimetric image C-band SAR data acquired by Radarsat-2, over San Francisco Bay area was used for the evaluation of the proposed method.

  8. Area-Efficient Low Power CMOS Image Sensor Readout Circuit with Fixed Pattern Noise Cancellation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shibin; YAO Suying; NIE Kaiming; XU Jiangtao

    2010-01-01

    A low cost of die area and power consumption CMOS image sensor readout circuit with fixed pattern noise(FPN)cancellation is proposed.By using only one coupling capacitor and switch in the double FPN cancelling correlative double sampling(CDS),pixel FPN is cancelled and column FPN is stored and eliminated by the sample-and-hold operation of digitally programmable gain amplifier(DPGA).The bandwidth balance technology based on operational amplifier(op-amp)sharing is also introduced to decrease the power dissipation of traditional multi-stage switched capacitor DPGA.The circuit is designed and simulated using 1P6M 0.18 μm 1.8 V/3.3 V process.Simulation results indicate that the proposed CDS scheme can achieve an FPN of less than 1 mV.The total sampling capacitor per column is 0.9 pF and no column-wise power is dissipated.The die area and FPN value are cut by 70% and 41% respectively compared with amplifier-based CDS.The op-amp sharing gain stage can achieve a 12-bit precision and also implement an 8-bit gain controlling within a gain range of 24 dB.Its power consumption is 1.4 mW,which is reduced by 57% compared with traditional schemes.The proposed readout circuit is suitable for the application of low power cost-sensitive imaging systems.

  9. An automatic water body area monitoring algorithm for satellite images based on Markov Random Fields

    Science.gov (United States)

    Elmi, Omid; Tourian, Mohammad J.; Sneeuw, Nico

    2016-04-01

    Our knowledge about spatial and temporal variation of hydrological parameters are surprisingly poor, because most of it is based on in situ stations and the number of stations have reduced dramatically during the past decades. On the other hand, remote sensing techniques have proven their ability to measure different parameters of Earth phenomena. Optical and SAR satellite imagery provide the opportunity to monitor the spatial change in coastline, which can serve as a way to determine the water extent repeatedly in an appropriate time interval. An appropriate classification technique to separate water and land is the backbone of each automatic water body monitoring. Due to changes in the water level, river and lake extent, atmosphere, sunlight radiation and onboard calibration of the satellite over time, most of the pixel-based classification techniques fail to determine accurate water masks. Beyond pixel intensity, spatial correlation between neighboring pixels is another source of information that should be used to decide the label of pixels. Water bodies have strong spatial correlation in satellite images. Therefore including contextual information as additional constraint into the procedure of water body monitoring improves the accuracy of the derived water masks significantly. In this study, we present an automatic algorithm for water body area monitoring based on maximum a posteriori (MAP) estimation of Markov Random Fields (MRF). First we collect all available images from selected case studies during the monitoring period. Then for each image separately we apply a k-means clustering to derive a primary water mask. After that we develop a MRF using pixel values and the primary water mask for each image. Then among the different realizations of the field we select the one that maximizes the posterior estimation. We solve this optimization problem using graph cut techniques. A graph with two terminals is constructed, after which the best labelling structure for

  10. Ground Deformation Extraction Using Visible Images and LIDAR Data in Mining Area

    Science.gov (United States)

    Hu, Wenmin; Wu, Lixin

    2016-06-01

    Recognition and extraction of mining ground deformation can help us understand the deformation process and space distribution, and estimate the deformation laws and trends. This study focuses on the application of ground deformation detection and extraction combining with high resolution visible stereo imagery, LiDAR observation point cloud data and historical data. The DEM in large mining area is generated using high-resolution satellite stereo images, and ground deformation is obtained through time series analysis combined with historical DEM data. Ground deformation caused by mining activities are detected and analyzed to explain the link between the regional ground deformation and local deformation. A district of covering 200 km2 around the West Open Pit Mine in Fushun of Liaoning province, a city located in the Northeast China is chosen as the test area for example. Regional and local ground deformation from 2010 to 2015 time series are detected and extracted with DEMs derived from ZY-3 images and LiDAR point DEMs in the case study. Results show that the mean regional deformation is 7.1 m of rising elevation with RMS 9.6 m. Deformation of rising elevation and deformation of declining elevation couple together in local area. The area of higher elevation variation is 16.3 km2 and the mean rising value is 35.8 m with RMS 15.7 m, while the deformation area of lower elevation variation is 6.8 km2 and the mean declining value is 17.6 m with RMS 9.3 m. Moreover, local large deformation and regional slow deformation couple together, the deformation in local mining activities has expanded to the surrounding area, a large ground fracture with declining elevation has been detected and extracted in the south of West Open Pit Mine, the mean declining elevation of which is 23.1 m and covering about 2.3 km2 till 2015. The results in this paper are preliminary currently; we are making efforts to improve more precision results with invariant ground control data for validation.

  11. Reflection seismic imaging in the volcanic area of the geothermal field Wayang Windu, Indonesia

    Science.gov (United States)

    Polom, Ulrich; Wiyono, Wiyono; Pramono, Bambang; Krawczyk, CharLotte M.

    2014-05-01

    Reflection seismic exploration in volcanic areas is still a scientific challenge and requires major efforts to develop imaging workflows capable of an economic utilization, e.g., for geothermal exploration. The SESaR (Seismic Exploration and Safety Risk study for decentral geothermal plants in Indonesia) project therefore tackles still not well resolved issues concerning wave propagation or energy absorption in areas covered by pyroclastic sediments using both active P-wave and S-wave seismics. Site-specific exploration procedures were tested in different tectonic and lithological regimes to compare imaging conditions. Based on the results of a small-scale, active seismic pre-site survey in the area of the Wayang Windu geothermal field in November 2012, an additional medium-scale active seismic experiment using P-waves was carried out in August 2013. The latter experiment was designed to investigate local changes of seismic subsurface response, to expand the knowledge about capabilities of the vibroseis method for seismic surveying in regions covered by pyroclastic material, and to achieve higher depth penetration. Thus, for the first time in the Wayang Windu geothermal area, a powerful, hydraulically driven seismic mini-vibrator device of 27 kN peak force (LIAG's mini-vibrator MHV2.7) was used as seismic source instead of the weaker hammer blow applied in former field surveys. Aiming at acquiring parameter test and production data southeast of the Wayang Windu geothermal power plant, a 48-channel GEODE recording instrument of the Badan Geologi was used in a high-resolution configuration, with receiver group intervals of 5 m and source intervals of 10 m. Thereby, the LIAG field crew, Star Energy, GFZ Potsdam, and ITB Bandung acquired a nearly 600 m long profile. In general, we observe the successful applicability of the vibroseis method for such a difficult seismic acquisition environment. Taking into account the local conditions at Wayang Windu, the method is

  12. Representation of Block-Based Image Features in a Multi-Scale Framework for Built-Up Area Detection

    OpenAIRE

    Zhongwen Hu; Qingquan Li; Qian Zhang; Guofeng Wu

    2016-01-01

    The accurate extraction and mapping of built-up areas play an important role in many social, economic, and environmental studies. In this paper, we propose a novel approach for built-up area detection from high spatial resolution remote sensing images, using a block-based multi-scale feature representation framework. First, an image is divided into small blocks, in which the spectral, textural, and structural features are extracted and represented using a multi-scale framework; a set of refin...

  13. LAND STREAMER SEISMIC DATA FROM NORTHERN DELAWARE: A VIABLE ALTERNATIVE FOR IMAGING AQUIFERS IN SUBURBAN AREAS

    Science.gov (United States)

    Velez, C. C.; McLaughlin, P. P.; McGeary, S. E.; Sargent, S. L.

    2009-12-01

    The Potomac Formation includes the most important confined aquifers in the Coastal Plain of northern Delaware. Development and a growing suburban population are increasing demand for groundwater in the area, making accurate assessment of groundwater water supply increasingly important. Previous studies of subsurface geology indicate that the Potomac Formation is characterized by laterally discontinuous fluvial sand bodies, making it difficult to precisely delineate the distribution and geometry of the aquifer facies based on well correlations alone. A 20-km high-resolution seismic reflection dataset was collected using a land-streamer system in 2008 to constrain subsurface stratigraphy between disparate well locations. The data were collected along roadways in an area of mixed development that includes suburban housing tracts, farmlands, and large industry. A 152-m-deep continuous-cored test hole was drilled in the summer of 2009 adjacent to one of the lines and a full suite of borehole geophysical logs obtained. The land-streamer data are compared to a 3-km dataset collected also in 2008 using conventional methods on farmland in the northern part of the study area. The land streamer system proved to be more effective than conventional seismic reflection methods in this area. Several advantages are evident for the land streamer: 1) overall, the conventional dataset has a higher S/N, 2) on average, collecting data with the land streamer system is four times faster, and 3) the land streamer lines can be longer and therefore more continuous than the conventional lines in a developed area. The land-streamer system has minor disadvantages: traffic control, traffic noise, and in some cases a need for larger crews. Regardless, the land streamer dataset is easier to process, of higher quality, and more cost effective. The final depth images from the land streamer data indicate that the minimum and maximum depths imaged are ~18 m and ~ 268m, with a resolution of ~4 m. This

  14. High Resolution Imaging Spectroscopy for Characterizing Soil Properties over Large Areas

    Science.gov (United States)

    Dutta, D.; Kumar, P.

    2014-12-01

    Quantitative mapping of high resolution surface soil texture (percentage sand, silt and clay), soil organic matter and chemical constituents are important for understanding infiltration, runoff and other surficial hydrologic processes at different scales. The Visible Near Infrared Analysis (VNIRA) method, which is a combination of imaging spectroscopy and laboratory chemical analysis with an underlying statistical model, has been established for the quantification of soil properties from imaging spectrometer data. In this study we characterize the feasibility of quantifying soil properties over large areas with the aim that these methods may be extended to space-borne sensors such as HyspIRI. Hyperspectral Infrared Imager (HyspIRI) is a space-borne NASA mission concept having 10nm contiguous bands in the VSWIR region (380nm to 2500nm) of the electromagnetic spectra. High resolution (7.6m) Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data collected by NASA immediately after the massive 2011 Mississippi River floods at the Birds Point New Madrid (BPNM) floodway, coupled with in situ samples obtained at the time of the flight, is used to generate HyspIRI like data at 60m resolution. The VNIRA method is applied in a data-mining framework for quantification of the different soil textural properties and chemical constituents. The empirical models are further used for creating quantitative maps of the soil properties for the entire BPNM floodway. These maps are compared with the fine resolution AVIRIS maps of the same area for the different legacy landscape features and spatial correlations with the underlying topography immediately disturbed by the flooding event. The scales of variation in the soil constituents captured by the fine resolution data are also compared to the scales of variation captured by coarser resolution data. This study further explores the issues of applicability, challenges (such as the sensitivity of NDVI from mixed neighborhood pixels

  15. Automatic extraction analysis of the anatomical functional area for normal brain 18F-FDG PET imaging

    International Nuclear Information System (INIS)

    Using self-designed automatic extraction software of brain functional area, the grey scale distribution of 18F-FDG imaging and the relationship between the 18F-FDG accumulation of brain anatomic function area and the 18F-FDG injected dose, the level of glucose, the age, etc., were studied. According to the Talairach coordinate system, after rotation, drift and plastic deformation, the 18F-FDG PET imaging was registered into the Talairach coordinate atlas, and then the average gray value scale ratios between individual brain anatomic functional area and whole brain area was calculated. Further more the statistics of the relationship between the 18F-FDG accumulation of every brain anatomic function area and the 18F-FDG injected dose, the level of glucose and the age were tested by using multiple stepwise regression model. After images' registration, smoothing and extraction, main cerebral cortex of the 18F-FDG PET brain imaging can be successfully localized and extracted, such as frontal lobe, parietal lobe, occipital lobe, temporal lobe, cerebellum, brain ventricle, thalamus and hippocampus. The average ratios to the inner reference of every brain anatomic functional area were 1.01 ± 0.15. By multiple stepwise regression with the exception of thalamus and hippocampus, the grey scale of all the brain functional area was negatively correlated to the ages, but with no correlation to blood sugar and dose in all areas. To the 18F-FDG PET imaging, the brain functional area extraction program could automatically delineate most of the cerebral cortical area, and also successfully reflect the brain blood and metabolic study, but extraction of the more detailed area needs further investigation

  16. Considerations about Large Area___Low Cost Fast Imaging Photo-detectors

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, John; /Argonne; Attenkofer, Klaus; /Argonne; Delagnes, Eric; /DAPNIA, Saclay; Frisch, Henry; /Chicago U., EFI; Genat, Jean-Francois; /Paris U., VI-VII; Grabas, Herve; /Chicago U., EFI; Heintz, Mary K.; /Chicago U., EFI; May, Edward; /Argonne; Meehan, Samuel; /Argonne; Oberla, Eric; /Argonne; Ruckman, Larry L.; /Hawaii U.; Tang, Fukun; /Chicago U., EFI; Varner, Gary; /Hawaii U.; Vavra, Jaroslav; /SLAC; Wetstein, Matthew; /Argonne

    2012-05-07

    The Large Area Picosecond Photodetectors described in this contribution incorporate a photocathode and a borosilicate glass capillary Micro-Channel Plate (MCP) pair functionalised by atomic layer deposition (ALD) of separate resistive and secondary emission materials. Initial testing with matched pairs of small glass capillary test disks has demonstrated gains of the order of 10{sup 5}-10{sup 6}. Compared to other fast imaging devices, these photodetectors are expected to provide timing resolutions in the 10-100 ps range, and two-dimension position in the sub-millimeter range. If daisy chained, large detectors read at both ends with fast digitising integrated electronics providing zero-suppressed calibrated data should be produced at relatively low cost in large quantities.

  17. High Speed and Area Efficient 2D DWT Processor Based Image Compression

    Directory of Open Access Journals (Sweden)

    Sugreev Kaur

    2011-02-01

    Full Text Available This paper presents a high speed and area efficient DWT processor based design for Image Compressionapplications. In this proposed design, pipelined partially serial architecture has been used to enhance thespeed along with optimal utilization and resources available on target FPGA. The proposed model hasbeen designed and simulated using Simulink and System Generator blocks, synthesized with XilinxSynthesis tool (XST and implemented on Spartan 2 and 3 based XC2S100-5tq144 and XC3S500E-4fg320target device. The results show that proposed design can operate at maximum frequency 231 MHz in caseof Spartan 3 by consuming power of 117mW at 28 degree/c junction temperature. The result comparisonhas shown an improvement of 15% in speed.

  18. Cosmo-SkyMed and RADARSAT2 image investigation for the monitoring of agricultural areas

    Science.gov (United States)

    Paloscia, S.; Pettinato, S.; Santi, E.; Notarnicola, C.; Greifeneder, F.; Cuozzo, G.; Nicolini, I.; Demir, B.; Bruzzone, L.

    2015-10-01

    This research aims at investigating the backscatter sensitivity at C and X band to the characteristics of agricultural surfaces and analyzing the integration of these data collected from Radarsat2 (RS2) and COSMO-SkyMed (CSK) systems on tree agricultural test areas in Italy (San Pietro Capofiume, in Emilia Romagna, Sesto Fiorentino, in Tuscany, and Mazia Valley, in South Tyrol). A preliminary test of the sensitivity of SAR signal to the soil and vegetation characteristics was first carried out by also comparing data from previous experiments. From these results, it can be concluded that X-band data are mainly sensitive to vegetation structure and biomass, and to soil moisture of bare or slightly vegetate soils, whereas C-band images could provide valuable information for the retrieval of soil moisture, even in vegetation covered soils. Two retrieval algorithms were implemented for estimating the main geophysical parameters, namely soil moisture content (SMC) and vegetation biomass (PWC) from these sensors. Over Sesto Fiorentino area, an algorithm based on Artificial Neural Network (ANN) technique was implemented for estimating both SMC of bare or scarcely vegetated soil and vegetation biomass of wheat crops at X band. On the South-Tyrol area, a SMC retrieval approach based on the Support Vector Regression methodology, which was already tested in this area using C-band data from ENVISAT/ASAR data, was adopted. This algorithm integrated data at both X and C bands showing encouraging results, even though further investigations shall be carried out on a larger time-series and larger set of samples.

  19. Monitoring of wildfires in boreal forests using large area AVHRR NDVI composite image data

    Energy Technology Data Exchange (ETDEWEB)

    Kasischke, E.S.; French, N.H.F. (Environmental Research Inst. of Michigan, Ann Arbor (United States)); Harrell, P.; Christensen, N.L. Jr. (Duke Univ., Durham, NC (United States)); Ustin, S.L. (Univ. of California, Davis (United States)); Barry, D. (U.S. Bureau of Land Management, Fairbanks, AK (United States))

    1993-06-01

    Normalized difference vegetation index (NDVI) composite image data, produced from AVHRR data collected in 1990, were evaluated for locating and mapping the areal extent of wildfires in the boreal forests of Alaska during that year. A technique was developed to map forest fire boundaries by subtracting a late-summer AVHRR NDVI image from an early summer scene. The locations and boundaries of wildfires within the interior region of Alaska were obtained from the Alaska Fire Service, and compared to the AVHRR-derived fire-boundary map. It was found that AVHRR detected 89.5% of all fires with sizes greater than 2,000ha with no false alarms and that, for most cases, the general shape of the fire boundary detected by AVHRR matched those mapped by field observers. However, the total area contained within the fire boundaries mapped by AVHRR were only 61% of those mapped by the field observers. However, the AVHRR data used in this study did not span the entire time period during which fires occurred, and it is believed the areal estimates could be improved significantly if an expanded AVHRR data set were used.

  20. Area estimation from a sample of satellite images: The impact of stratification on the clustering efficiency

    Science.gov (United States)

    Gallego, Francisco Javier; Stibig, Hans Jürgen

    2013-06-01

    Several projects dealing with land cover area estimation in large regions consider samples of sites to be analysed with high or very high resolution satellite images. This paper analyses the impact of stratification on the efficiency of sampling schemes of large-support units or clusters with a size between 5 km × 5 km and 30 km × 30 km. Cluster sampling schemes are compared with samples of unclustered points, both without and with stratification. The correlograms of land cover classes provide a useful tool to assess the sampling value of clusters in terms of variance; this sampling value is expressed as “equivalent number of points” of a cluster. We show that the “equivalent number of points” is generally higher for stratified cluster sampling than for non-stratified cluster sampling, whose values remain however moderate. When land cover data are acquired by photo-interpretation of tiles extracted from larger images, such as Landsat TM, a sampling plan based on a larger number of smaller clusters might be more efficient.

  1. Image Obfuscation in the User-Friendly Sensitive Area with the Use of a Sensor for Smart Devices and Image Processing Techniques

    OpenAIRE

    Kyoung-nam Kim; MyounJae Lee

    2014-01-01

    There are many different sensors such as gyroscope sensor, accelerometer sensor, and light sensor for smart devices. These sensors are applied in many fields such as health and medicine, education, augmented reality, and arts. This study aimed to create user-friendly artistic sensibility related to images in the sensitive areas needed for privacy protection by using a sensor in a smart phone and image processing techniques such as contour extraction, blurring, blending, and brightness adjustm...

  2. Building Extraction from High Resolution Space Images in High Density Residential Areas in the Great Cairo Region

    Directory of Open Access Journals (Sweden)

    Mohamed A. Sherief

    2011-04-01

    Full Text Available This study evaluates a methodology for using IKONOS stereo imagery to determine the height and position of buildings in dense residential areas. The method was tested on three selected sites in an area of 8.5 km long by 7 km wide and covered by two overlapping (97% overlap IKONOS images. The images were oriented using rational function models in addition to ground control points. Buildings were identified using an algorithm that utilized the Digital Surface Model (DSM extracted from the images in addition to the image spectral properties. A digital terrain model was used with the DSM created from the IKONOS stereo imagery to compute building heights. Positional accuracy and building heights were evaluated using corner coordinates extracted from topographic maps and surveyed building heights. The results showed that the average building detection percentage for the test area was 82.6% with an average missing factor of 0.16. When the image rational polynomial coefficients were used to build the image model, results showed a horizontal accuracy of 2.42 and 2.39 m Root Mean Square Error (RMSE for the easting and northing coordinates, respectively. When ground control points were used, the results improved to the sub-meter level. Differences between building heights extracted from the image model and the corresponding heights obtained through traditional ground surveying had a RMSE of 1.05 m.

  3. San Francisco Bay Area Velocity Structure From Controlled-Source Seismic Refraction Imaging

    Science.gov (United States)

    Goldman, M. R.; Catchings, R. D.; Steedman, C. E.; Gandhok, G.; Boatwright, J.; Rymer, M. J.

    2004-12-01

    To better understand the velocities and structures of the crust and upper mantle in the San Francisco Bay area, we developed 2-D tomographic velocity models along four seismic refraction profiles acquired along and across the bay area in the early 1990's. The four profiles extended from (1) Hollister to Inverness along the San Francisco and Marin Peninsulas (~200 km long), (2) Hollister to Santa Rosa along the East Bay (~220 km long), (3) the Pacific Ocean to Livermore crossing the bay (~100 km long), and (4) the Pacific Ocean to the western Santa Clara Valley (~25 km long), centered on the epicenter of the1989 M. 6.9 Loma Prieta earthquake. Velocity models were not previously developed for three of the seismic profiles, and the previously developed model for the fourth profile (Catchings and Kohler, 1996) did not include some of the currently available seismic data. The profiles along the bay image structures from the near surface to about 25 km depth, and they show velocity anomalies associated with the major faults (San Andreas, Hayward, Rodgers Creek, Calaveras) and basins along the profile. Velocities range from about 2 km/s in the basins to about 7 km/s at the Moho, which dips southward along both sides of the bay. The cross bay profile shows velocity anomalies associated with six fault zones between the Pacific Ocean and the Livermore Valley and higher upper-crustal velocities (~6.2 km/s) between the San Andreas and Hayward faults than to the southwest (~5 km/s) or northeast (~4 km/s) of those faults. The Loma Prieta profile shows velocities ranging from 2 km/s to 6 km/s in the upper 5 km, with the highest velocities in the epicentral region of the 1989 Loma Prieta earthquake. A pronounced, northeast-dipping, low-velocity zone is located beneath the surface expression of the San Andreas fault zone, but other fault zones along the profile show high-velocity anomalies beneath their surface expressions. Collectively, the velocity images show the complexity of

  4. Joint Geophysical Imaging of the Utah Area Using Seismic Body Waves, Surface Waves and Gravity Data

    Science.gov (United States)

    Zhang, H.; Maceira, M.; Toksoz, M. N.; Burlacu, R.; Yang, Y.

    2009-12-01

    We present a joint geophysical imaging method that makes use of seismic body wave arrival times, surface wave dispersion measurements, and gravity data to determine three-dimensional (3D) Vp and Vs models. An empirical relationship mapping densities to Vp and Vs for earth materials is used to link them together. The joint inversion method takes advantage of strengths of individual data sets and is able to better constrain the velocity models from shallower to greater depths. Combining three different data sets to jointly invert for the velocity structure is equivalent to a multiple-objective optimization problem. Because it is unlikely that the different “objectives” (data types) would be optimized by the same parameter choices, some trade-off between the objectives is needed. The optimum weighting scheme for different data types is based on relative uncertainties of individual observations and their sensitivities to model parameters. We will apply this joint inversion method to determine 3D Vp and Vs models of the Utah area. The seismic body wave arrival times are assembled from waveform data recorded by the University of Utah Seismograph Stations (UUSS) regional network for the past 7 years. The surface wave dispersion measurements are obtained from the ambient noise tomography study by the University of Colorado group using EarthScope/USArray stations. The gravity data for the Utah area is extracted from the North American Gravity Database managed by the University of Texas at El Paso. The preliminary study using the seismic body wave arrival times indicates strong low velocity anomalies in middle crust beneath some known geothermal sites in Utah. The joint inversion is expected to produce a reasonably well-constrained velocity structure of the Utah area, which is helpful for characterizing and exploring existing and potential geothermal reservoirs.

  5. Monitoring Soil Moisture in a Coal Mining Area with Multi-Phase Landsat Images

    Science.gov (United States)

    Kong, J. L.; Xian, T.; Yang, J.; Chen, L.; Yang, X. T.

    2016-06-01

    The coal development zone of Northern Shaanxi, China is one of the eight largest coal mines in the world, also the national energy and chemical bases. However, the coal mining leads to ground surface deformation and previous studies show that in collapse fissure zone soil water losses almost 50% compared with non-fissure zone. The main objective of this study is to develop a retrieval model that is reliable and sensitive to soil moisture in the whole coal mining zone of Northern Shaanxi based upon the soil sample parameters collected from in situ site investigation, spectral data gathered simultaneously and the images of Landsat7 ETM. The model uses different phases of Landsat data to retrieve soil moisture and analyze the patterns of spatial and temporal variations of soil moisture caused by ground deformation in the coal mining areas. The study indicated that band4 of Landsat7 ETM is the most sensitive band for soil moisture retrieval using the spectrum method. The quadratic model developed by remote sensing reflectance (Rrs4) (corresponding to the band4) is the best pattern with the correlation coefficient of 0.858 between the observed and the estimated soil moisture. Two-phase Landsat7 ETM data of 2002 and 2009 and one phase Landsat8 OLI data of 2015 for the study area were selected to retrieve soil moisture information. The result showed that the mean relative error was 35.16% and the root-mean-squared error (RMSE) was 0.58%. The changes of the spatial distribution of inversed soil moisture revealed that the trend of soil moisture contents of the study area was in general being gradually reduced from 2002 to 2015. The study results can serve as the baseline for monitoring environmental impacts on soil moisture in the regions due to coal mining.

  6. Case study on the extraction of land cover information from the SAR image of a coal mining area

    Institute of Scientific and Technical Information of China (English)

    HU Zhao-ling; LI Hai-quan; DU Pei-jun

    2009-01-01

    In this study, analyses are conducted on the information features of a construction site, a cornfield and subsidence seeper land in a coal mining area with a synthetic aperture radar (SAR) image of medium resolution. Based on features of land cover of the coal mining area, on texture feature extraction and a selection method of a gray-level co-occurrence matrix (GLCM) of the SAR image, we propose in this study that the optimum window size for computing the GLCM is an appropriate sized window that can effectively distinguish different types of land cover. Next, a band combination was carried out over the text feature images and the band-filtered SAR image to secure a new multi-band image. After the transformation of the new image with principal component analysis, a classification is conducted selectively on three principal component bands with the most information. Finally, through training and experimenting with the samples, a better three-layered BP neural network was established to classify the SAR image. The results show that, assisted by texture information, the neural network classification improved the accuracy of SAR image clas-sification by 14.6%, compared with a classification by maximum likelihood estimation without texture information.

  7. A double fluorescence staining protocol to determine the cross-sectional area of myofibers using image analysis

    Science.gov (United States)

    Mozdziak, P. E.; Fassel, T. A.; Schultz, E.; Greaser, M. L.; Cassens, R. G.

    1996-01-01

    A double fluorescence staining protocol was developed to facilitate computer based image analysis. Myofibers from experimentally treated (irradiated) and control growing turkey skeletal muscle were labeled with the anti-myosin antibody MF-20 and detected using fluorescein-5-isothiocyanate (FITC). Extracellular material was stained with concanavalin A (ConA)-Texas red. The cross-sectional area of the myofibers was determined by calculating the number of pixels (0.83 mu m(2)) overlying each myofiber after subtracting the ConA-Texas red image from the MF-20-FITC image for each region of interest. As expected, myofibers in the irradiated muscle were smaller (P staining protocol combined with image analysis is accurate and less labor-intensive than classical procedures for determining the cross-sectional area of myofibers.

  8. Development of highly efficient large-area a-Si PV module. Final report; Entwicklung hocheffizienter grossflaechiger a-Si-Photovoltaikmodule. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Ruebel, H.; Frammelsberger, W.; Lechner, P.; Geyer, R.; Schade, H.; Psyk, W.

    1998-06-01

    This project was focused on the development of stable PV modules based on a-Si, and on the process transfer from a laboratory scale to a large-area production level. Central to these efforts is the economic relevance that requires reasonable module efficiencies obtained with high throughput and yield. Our modules contain p-i-n/p-i-n (a-Si/a-Si) cell structures that are based on deposition procedures developed at ISI, i.e. low-temperature deposition and high hydrogen dilution for the top cell, and microdoping between the p-layer and the buffer layer for the cottom cell. The maximum stabilized (1800 h) module efficiency obtained by production-relevant processes is 6.5% for the aperture area of 5445 cm{sup 2}. (orig.) [Deutsch] Die Arbeiten im Rahmen des Projekts konzentrierten sich auf die Entwicklung moeglicht stabiler a-Si-PV-Module und auf die Umsetzung vorhandener Labortechniken in einen industriellen Fertigungsmassstab. Mitbestimmend fuer die Entwicklungsarbeiten war die kommerzielle Relevanz, die brauchbare Modulleistungen verknuepft mit hohem Durchsatz bei hoher Ausbeute. Die Basis fuer unsere jetzige Zellstruktur im Modul sind die a-Si/a-Si-(p-i-n/p-i-n)-Technologie und die Technologiekonzepte des ISI (Tieftemperaturabscheidung bei hoher H-Verduennung fuer die Topzelle sowie Feindotierung des Uebergangs von der p-Schicht in den Puffer hinein fuer die Bottomzelle). Das beste mit einem fertigungsrelevanten Prozess hergestellte Modul erreicht nach 1800 h Lichtalterung einen stabilisierten Aperturwirkungsgrad von 6.5%. (orig.)

  9. Phase contrast imaging reveals low lung volumes and surface areas in the developing marsupial.

    Directory of Open Access Journals (Sweden)

    Shannon J Simpson

    Full Text Available Marsupials are born with immature lungs when compared to eutherian mammals and rely, to various extents, on cutaneous gas exchange in order to meet metabolic requirements. Indeed, the fat-tailed dunnart is born with lungs in the canalicular stage of development and relies almost entirely on the skin for gas exchange at birth; consequently undergoing the majority of lung development in air. Plane radiographs and computed tomography data sets were acquired using phase contrast imaging with a synchrotron radiation source for two marsupial species, the fat-tailed dunnart and the larger tammar wallaby, during the first weeks of postnatal life. Phase contrast imaging revealed that only two lung sacs contain air after the first hour of life in the fat-tailed dunnart. While the lung of the tammar wallaby was comparatively more developed, both species demonstrated massive increases in air sac number and architectural complexity during the postnatal period. In addition, both the tammar wallaby and fat-tailed dunnart had lower lung volumes and parenchymal surface areas than were expected from morphometrically determined allometric equations relating these variables to body mass during the neonatal period. However, lung volume is predicted to scale with mass as expected after the neonatal marsupial reaches a body mass of ∼1 g and no longer relies on the skin for gas exchange. Decreased lung volume in the marsupial neonate further supports the maxim that cutaneous gas exchange occurs in the marsupial neonate because the respiratory apparatus is not yet capable of meeting the gas exchange requirements of the newborn.

  10. Fusion of Hyperspectral and Vhr Multispectral Image Classifications in Urban Areas

    Science.gov (United States)

    Hervieu, Alexandre; Le Bris, Arnaud; Mallet, Clément

    2016-06-01

    An energetical approach is proposed for classification decision fusion in urban areas using multispectral and hyperspectral imagery at distinct spatial resolutions. Hyperspectral data provides a great ability to discriminate land-cover classes while multispectral data, usually at higher spatial resolution, makes possible a more accurate spatial delineation of the classes. Hence, the aim here is to achieve the most accurate classification maps by taking advantage of both data sources at the decision level: spectral properties of the hyperspectral data and the geometrical resolution of multispectral images. More specifically, the proposed method takes into account probability class membership maps in order to improve the classification fusion process. Such probability maps are available using standard classification techniques such as Random Forests or Support Vector Machines. Classification probability maps are integrated into an energy framework where minimization of a given energy leads to better classification maps. The energy is minimized using a graph-cut method called quadratic pseudo-boolean optimization (QPBO) with ?-expansion. A first model is proposed that gives satisfactory results in terms of classification results and visual interpretation. This model is compared to a standard Potts models adapted to the considered problem. Finally, the model is enhanced by integrating the spatial contrast observed in the data source of higher spatial resolution (i.e., the multispectral image). Obtained results using the proposed energetical decision fusion process are shown on two urban multispectral/hyperspectral datasets. 2-3% improvement is noticed with respect to a Potts formulation and 3-8% compared to a single hyperspectral-based classification.

  11. Reflection seismic imaging of a hydraulically conductive fracture zone in a high noise area, Forsmark, Sweden

    Science.gov (United States)

    Juhlin, C.; Stephens, M. B.; Cosma, C.

    2007-05-01

    High resolution reflection seismic methods have proven to be useful tools for locating fracture zones in crystalline rock. Siting of potential high-level nuclear waste repositories is a particularly important application of these methods. By using small explosive sources (15-75 grams), high resolution images of the sub-surface have been obtained in the depth range 100 m to 2 km in Sweden, Canada and elsewhere. Although ambient noise conditions in areas such as the Fennoscandian and Canadian shields are generally low, industrial noise can be high in some areas, particularly at potential sites suitable for repositories, since these are often close to existing infrastructure. In addition, the presence of this infrastructure limits the choice of sources available to the geophysicist. Forsmark, located about 140 km north of Stockholm, is one such potential site where reflection seismics have been carried out. Existing infrastructure includes nuclear reactors for power generation and a low- level waste repository. In the vicinity of the reactors, it was not possible to use an explosive source due to permitting restrictions. Instead, a VIBSIST system consisting of a tractor mounted hydraulic hammer was used in the vicinity of the reactors. By repeatedly hitting the pavement, without breaking it, at predefined sweeps and then stacking the signals, shot records comparable to explosive data could be generated. These shot records were then processed using standard methods to produce stacked sections along 3 profiles within the reactor area. Clear reflections are seen in the uppermost 600 m along 3 of these profiles. Correlation of crossing profiles shows that the strongest reflection (B8) is generated by a gently east-southeast dipping interface. Prior to construction of the reactors, several boreholes were drilled to investigate the bedrock in the area. One of these boreholes was located close to where two of the profiles cross. Projection of the B8 reflection into the

  12. Four-Dimensional Magnetic Resonance Imaging Using Axial Body Area as Respiratory Surrogate: Initial Patient Results

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Juan [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); School of Information Science and Engineering, Shandong University, Jinan, Shandong (China); Cai, Jing [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Wang, Hongjun [School of Information Science and Engineering, Shandong University, Jinan, Shandong (China); Chang, Zheng; Czito, Brian G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Bashir, Mustafa R. [Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Yin, Fang-Fang, E-mail: fangfang.yin@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

    2014-03-15

    Purpose: To evaluate the feasibility of a retrospective binning technique for 4-dimensional magnetic resonance imaging (4D-MRI) using body area (BA) as a respiratory surrogate. Methods and Materials: Seven patients with hepatocellular carcinoma (4 of 7) or liver metastases (3 of 7) were enrolled in an institutional review board-approved prospective study. All patients were simulated with both computed tomography (CT) and MRI to acquire 3-dimensinal and 4D images for treatment planning. Multiple-slice multiple-phase cine-MR images were acquired in the axial plane for 4D-MRI reconstruction. Image acquisition time per slice was set to 10-15 seconds. Single-slice 2-dimensinal cine-MR images were also acquired across the center of the tumor in orthogonal planes. Tumor motion trajectories from 4D-MRI, cine-MRI, and 4D-CT were analyzed in the superior–inferior (SI), anterior–posterior (AP), and medial–lateral (ML) directions, respectively. Their correlation coefficients (CC) and differences in tumor motion amplitude were determined. Tumor-to-liver contrast-to-noise ratio (CNR) was measured and compared between 4D-CT, 4D-MRI, and conventional T2-weighted fast spin echo MRI. Results: The means (±standard deviations) of CC comparing 4D-MRI with cine-MRI were 0.97 ± 0.03, 0.97 ± 0.02, and 0.99 ± 0.04 in SI, AP, and ML directions, respectively. The mean differences were 0.61 ± 0.17 mm, 0.32 ± 0.17 mm, and 0.14 ± 0.06 mm in SI, AP, and ML directions, respectively. The means of CC comparing 4D-MRI and 4D-CT were 0.95 ± 0.02, 0.94 ± 0.02, and 0.96 ± 0.02 in SI, AP, and ML directions, respectively. The mean differences were 0.74 ± 0.02 mm, 0.33 ± 0.13 mm, and 0.18 ± 0.07 mm in SI, AP, and ML directions, respectively. The mean tumor-to-tissue CNRs were 2.94 ± 1.51, 19.44 ± 14.63, and 39.47 ± 20.81 in 4D-CT, 4D-MRI, and T2-weighted MRI, respectively. Conclusions: The preliminary evaluation of our 4D-MRI technique results in oncologic patients demonstrates its

  13. OBJECT BASED AGRICULTURAL LAND COVER CLASSIFICATION MAP OF SHADOWED AREAS FROM AERIAL IMAGE AND LIDAR DATA USING SUPPORT VECTOR MACHINE

    Directory of Open Access Journals (Sweden)

    R. T. Alberto

    2016-06-01

    Full Text Available Aerial image and LiDAR data offers a great possibility for agricultural land cover mapping. Unfortunately, these images leads to shadowy pixels. Management of shadowed areas for classification without image enhancement were investigated. Image segmentation approach using three different segmentation scales were used and tested to segment the image for ground features since only the ground features are affected by shadow caused by tall features. The RGB band and intensity were the layers used for the segmentation having an equal weights. A segmentation scale of 25 was found to be the optimal scale that will best fit for the shadowed and non-shadowed area classification. The SVM using Radial Basis Function kernel was then applied to extract classes based on properties extracted from the Lidar data and orthophoto. Training points for different classes including shadowed areas were selected homogeneously from the orthophoto. Separate training points for shadowed areas were made to create additional classes to reduced misclassification. Texture classification and object-oriented classifiers have been examined to reduced heterogeneity problem. The accuracy of the land cover classification using 25 scale segmentation after accounting for the shadow detection and classification was significantly higher compared to higher scale of segmentation.

  14. Object Based Agricultural Land Cover Classification Map of Shadowed Areas from Aerial Image and LIDAR Data Using Support Vector Machine

    Science.gov (United States)

    Alberto, R. T.; Serrano, S. C.; Damian, G. B.; Camaso, E. E.; Celestino, A. B.; Hernando, P. J. C.; Isip, M. F.; Orge, K. M.; Quinto, M. J. C.; Tagaca, R. C.

    2016-06-01

    Aerial image and LiDAR data offers a great possibility for agricultural land cover mapping. Unfortunately, these images leads to shadowy pixels. Management of shadowed areas for classification without image enhancement were investigated. Image segmentation approach using three different segmentation scales were used and tested to segment the image for ground features since only the ground features are affected by shadow caused by tall features. The RGB band and intensity were the layers used for the segmentation having an equal weights. A segmentation scale of 25 was found to be the optimal scale that will best fit for the shadowed and non-shadowed area classification. The SVM using Radial Basis Function kernel was then applied to extract classes based on properties extracted from the Lidar data and orthophoto. Training points for different classes including shadowed areas were selected homogeneously from the orthophoto. Separate training points for shadowed areas were made to create additional classes to reduced misclassification. Texture classification and object-oriented classifiers have been examined to reduced heterogeneity problem. The accuracy of the land cover classification using 25 scale segmentation after accounting for the shadow detection and classification was significantly higher compared to higher scale of segmentation.

  15. Synthesizing monochromatic 3-D images by multiple-exposure rainbow holography with vertical area-partition approach

    Institute of Scientific and Technical Information of China (English)

    翟宏琛; 王明伟; 刘福民; 母国光

    2002-01-01

    We report for the first time the theoretical analysis and experimental results of a white-light reconstructed monochromatic 3-D image synthesizing tomograms by multiple rainbow holo-graphy with vertical-area partition (VAP) approach. The theoretical and experimental results show that 3-D monochromatic image can be synthesized by recording the master hologram by VAP ap-proach without any distortions either in gray scale or in geometrical position. A 3-D monochromatic image synthesized from a series of medical tomograms is presented in this paper for the first time.

  16. A strongly heterogeneous hydrothermal area imaged by surface waves: the case of Solfatara, Campi Flegrei, Italy

    Science.gov (United States)

    Serra, Marcello; Festa, Gaetano; Roux, Philippe; Gresse, Marceau; Vandemeulebrouck, Jean; Zollo, Aldo

    2016-06-01

    We investigated the shallow structure of the Solfatara, a volcano within the Campi Flegrei caldera, southern Italy, using surface waves as a diagnostic tool. We analysed data collected during the RICEN campaign, where a 3-D active seismic experiment was performed on a dense regular grid of 90 m × 115 m using a Vibroseis as the seismic source. After removal of the source time function, we analysed the surface wave contribution to the Green's function. Here, a 1-D approximation can hold for subgrids of 40 m × 40 m. Moreover, we stacked all of the signals in the subgrid according to source-receiver distance bins, despite the absolute location of the source and the receiver, to reduce the small-scale variability in the data. We then analysed the resulting seismic sections in narrow frequency bands between 7 and 25 Hz. We obtained phase and group velocities from a grid search, and a cost function based on the spatial coherence of both the waveforms and their envelopes. We finally jointly inverted the dispersion curves of the phase and group velocities to retrieve a 1-D S-wave model local to the subgrid. Together, the models provided a 3-D description of the S-wave model in the area. We found that the maximum penetration depth is 15 m. In the first 4 m, we can associate the changes in the S-wave field to the temperature gradient, while at greater depths, the seismic images correlate with the resistivity maps, which indicate the water layer close to the Fangaia area and an abrupt variation moving towards the northeast.

  17. A perception-inspired building index for automatic built-up area detection in high-resolution satellite images

    OpenAIRE

    Liu, Gang; Xia, Gui-Song; Huang, Xin; Yang, Wen; Zhang, Liangpei

    2013-01-01

    This paper addresses the problem of automatic extraction of built-up areas from high-resolution remote sensing images. We propose a new building presence index from the point view of perception. We argue that built-up areas usually result in significant corners and junctions in high-resolution satellite images, due to the man-made structures and occlusion, and thus can be measured by the geometrical structures they contained. More precisely, we first detect corners and junctions by relying on...

  18. A novel method for measuring anterior segment area of the eye on ultrasound biomicroscopic images using photoshop.

    Directory of Open Access Journals (Sweden)

    Zhonghao Wang

    Full Text Available To describe a novel method for quantitative measurement of area parameters in ocular anterior segment ultrasound biomicroscopy (UBM images using Photoshop software and to assess its intraobserver and interobserver reproducibility.Twenty healthy volunteers with wide angles and twenty patients with narrow or closed angles were consecutively recruited. UBM images were obtained and analyzed using Photoshop software by two physicians with different-level training on two occasions. Borders of anterior segment structures including cornea, iris, lens, and zonules in the UBM image were semi-automatically defined by the Magnetic Lasso Tool in the Photoshop software according to the pixel contrast and modified by the observers. Anterior chamber area (ACA, posterior chamber area (PCA, iris cross-section area (ICA and angle recess area (ARA were drawn and measured. The intraobserver and interobserver reproducibilities of the anterior segment area parameters and scleral spur location were assessed by limits of agreement, coefficient of variation (CV, and intraclass correlation coefficient (ICC.All of the parameters were successfully measured by Photoshop. The intraobserver and interobserver reproducibilities of ACA, PCA, and ICA were good, with no more than 5% CV and more than 0.95 ICC, while the CVs of ARA were within 20%. The intraobserver and interobserver reproducibilities for defining the spur location were more than 0.97 ICCs. Although the operating times for both observers were less than 3 minutes per image, there was significant difference in the measuring time between two observers with different levels of training (p<0.001.Measurements of ocular anterior segment areas on UBM images by Photoshop showed good intraobserver and interobserver reproducibilties. The methodology was easy to adopt and effective in measuring.

  19. Mapping landslide source and transport areas in VHR images with Object-Based Analysis and Support Vector Machines

    Science.gov (United States)

    Heleno, Sandra; Matias, Magda; Pina, Pedro

    2015-04-01

    Visual interpretation of satellite imagery remains extremely demanding in terms of resources and time, especially when dealing with numerous multi-scale landslides affecting wide areas, such as is the case of rainfall-induced shallow landslides. Applying automated methods can contribute to more efficient landslide mapping and updating of existing inventories, and in recent years the number and variety of approaches is rapidly increasing. Very High Resolution (VHR) images, acquired by space-borne sensors with sub-metric precision, such as Ikonos, Quickbird, Geoeye and Worldview, are increasingly being considered as the best option for landslide mapping, but these new levels of spatial detail also present new challenges to state of the art image analysis tools, asking for automated methods specifically suited to map landslide events on VHR optical images. In this work we develop and test a methodology for semi-automatic landslide recognition and mapping of landslide source and transport areas. The method combines object-based image analysis and a Support Vector Machine supervised learning algorithm, and was tested using a GeoEye-1 multispectral image, sensed 3 days after a damaging landslide event in Madeira Island, together with a pre-event LiDAR DEM. Our approach has proved successful in the recognition of landslides on a 15 Km2-wide study area, with 81 out of 85 landslides detected in its validation regions. The classifier also showed reasonable performance (false positive rate 60% and false positive rate below 36% in both validation regions) in the internal mapping of landslide source and transport areas, in particular in the sunnier east-facing slopes. In the less illuminated areas the classifier is still able to accurately map the source areas, but performs poorly in the mapping of landslide transport areas.

  20. Early developability screen of therapeutic antibody candidates using Taylor dispersion analysis and UV area imaging detection.

    Science.gov (United States)

    Lavoisier, Alexandra; Schlaeppi, Jean-Marc

    2015-01-01

    Therapeutic antibodies represent one of the fastest growing segments in the pharmaceutical market. They are used in a broad range of disease fields, such as autoimmune diseases, cancer, inflammation and infectious diseases. The growth of the segment has necessitated development of new analytical platforms for faster and better antibody selection and characterization. Early quality control and risk assessment of biophysical parameters help prevent failure in later stages of antibody development, and thus can reduce costs and save time. Critical parameters such as aggregation, conformational stability, colloidal stability and hydrophilicity, are measured during the early phase of antibody generation and guide the selection process of the best lead candidates in terms of technical developability. We report on the use of a novel instrument (ActiPix/Viscosizer) for measuring both the hydrodynamic radius and the absolute viscosity of antibodies based on Taylor dispersion analysis and UV area imaging. The looped microcapillary-based method combines low sample consumption, fast throughput and high precision compared to other conventional methods. From a random panel of 130 antibodies in the early selection process, we identified some with large hydrodynamic radius outside the normal distribution and others with non-Gaussian Taylor dispersion profiles. The antibodies with such abnormal properties were confirmed later in the selection process to show poor developability profiles. Moreover, combining these results with those of the viscosity measurements at high antibody concentrations allows screening, with limited amounts of materials, candidates with potential issues in pre-formulation development.

  1. Serial assessment of the area at risk in myocardial infarction with Gd-DTPA-enhanced MR imaging in humans

    International Nuclear Information System (INIS)

    Experimental studies have shown that the region of increased myocardial signal intensity with Gd-DTPA correlates with the area at risk but overestimates the infarct size. The authors have assessed the evolution of the area at risk in acute myocardial infarction in seven patients, using Gd-DTPA enhanced MR imaging at 1 and 2 weeks after the acute event. Multisection MR imaging of the total left ventricle was performed at 0.5 T after injection of 0.2 mmol/kg of Gd-DTPA. The area with a signal intensity greater than that of normal myocardium (± 2SDs) was designated as the area at risk in each section. The summation of these areas was measured by two observers at 1 and 2 weeks after infarction; intra- and interobserver variability was 3%. The area at risk ranged from 3% to 18%; at 2 weeks the size of the area at risk showed only slight changes (P = not significant). The authors discuss how Gd- DTPA enhances the area at risk and may be useful in assessing the evolution of the size of this area

  2. Spatial effects on the image and identity of a rural area

    NARCIS (Netherlands)

    Rijnks, Richard; Strijker, Dirk

    2013-01-01

    The Veenkoloniën is a relatively poor region within the peripheral north of the Netherlands. A negative regional image was suggested as one of the causes of this poverty. Our study focuses on what the images of the Veenkoloniën are within the Netherlands, and how the images change according to dista

  3. An Improved InSAR Image Co-Registration Method for Pairs with Relatively Big Distortions or Large Incoherent Areas.

    Science.gov (United States)

    Chen, Zhenwei; Zhang, Lei; Zhang, Guo

    2016-01-01

    Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR) data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration. Firstly, some geometric transformations including scale, flip, rotation, and shear between images were eliminated based on the geometrical information, and the initial co-registration polynomial was obtained. Then the registration points were automatically detected by integrating the signal-to-clutter-ratio (SCR) thresholds and the amplitude information, and a further co-registration process was performed to refine the polynomial. Several comparison experiments were carried out using 2 TerraSAR-X data from the Hong Kong airport and 21 PALSAR data from the Donghai Bridge. Experiment results demonstrate that the proposed method brings accuracy and efficiency improvements for co-registration and processing abilities in the cases of big distortion between images or large incoherent areas in the images. For most co-registrations, the proposed method can enhance the reliability and applicability of co-registration and thus promote the automation to a higher level. PMID:27649207

  4. An Improved InSAR Image Co-Registration Method for Pairs with Relatively Big Distortions or Large Incoherent Areas

    Science.gov (United States)

    Chen, Zhenwei; Zhang, Lei; Zhang, Guo

    2016-01-01

    Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR) data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration. Firstly, some geometric transformations including scale, flip, rotation, and shear between images were eliminated based on the geometrical information, and the initial co-registration polynomial was obtained. Then the registration points were automatically detected by integrating the signal-to-clutter-ratio (SCR) thresholds and the amplitude information, and a further co-registration process was performed to refine the polynomial. Several comparison experiments were carried out using 2 TerraSAR-X data from the Hong Kong airport and 21 PALSAR data from the Donghai Bridge. Experiment results demonstrate that the proposed method brings accuracy and efficiency improvements for co-registration and processing abilities in the cases of big distortion between images or large incoherent areas in the images. For most co-registrations, the proposed method can enhance the reliability and applicability of co-registration and thus promote the automation to a higher level. PMID:27649207

  5. An Improved InSAR Image Co-Registration Method for Pairs with Relatively Big Distortions or Large Incoherent Areas

    Directory of Open Access Journals (Sweden)

    Zhenwei Chen

    2016-09-01

    Full Text Available Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration. Firstly, some geometric transformations including scale, flip, rotation, and shear between images were eliminated based on the geometrical information, and the initial co-registration polynomial was obtained. Then the registration points were automatically detected by integrating the signal-to-clutter-ratio (SCR thresholds and the amplitude information, and a further co-registration process was performed to refine the polynomial. Several comparison experiments were carried out using 2 TerraSAR-X data from the Hong Kong airport and 21 PALSAR data from the Donghai Bridge. Experiment results demonstrate that the proposed method brings accuracy and efficiency improvements for co-registration and processing abilities in the cases of big distortion between images or large incoherent areas in the images. For most co-registrations, the proposed method can enhance the reliability and applicability of co-registration and thus promote the automation to a higher level.

  6. Mammography with and without radiolucent positioning sheets : Comparison of projected breast area, pain experience, radiation dose and technical image quality

    NARCIS (Netherlands)

    Timmers, Janine; ten Voorde, Marloes; van Engen, Ruben E.; van Landsveld-Verhoeven, Cary; Pijnappel, Ruud; Droogh-de Greve, Kitty; den Heeten, Gerard J.; Broeders, Mireille J. M.

    2015-01-01

    Purpose: To compare projected breast area, image quality, pain experience and radiation dose between mammography performed with and without radiolucent positioning sheets. Methods: 184 women screened in the Dutch breast screening programme (May-June 2012) provided written informed consent to have on

  7. Laser speckle contrast imaging identifies ischemic areas on gastric tube reconstructions following esophagectomy.

    Science.gov (United States)

    Milstein, Dan M J; Ince, Can; Gisbertz, Suzanne S; Boateng, Kofi B; Geerts, Bart F; Hollmann, Markus W; van Berge Henegouwen, Mark I; Veelo, Denise P

    2016-06-01

    Gastric tube reconstruction (GTR) is a high-risk surgical procedure with substantial perioperative morbidity. Compromised arterial blood supply and venous congestion are believed to be the main etiologic factors associated with early and late anastomotic complications. Identifying low blood perfusion areas may provide information on the risks of future anastomotic leakage and could be essential for improving surgical techniques. The aim of this study was to generate a method for gastric microvascular perfusion analysis using laser speckle contrast imaging (LSCI) and to test the hypothesis that LSCI is able to identify ischemic regions on GTRs.Patients requiring elective laparoscopy-assisted GTR participated in this single-center observational investigation. A method for intraoperative evaluation of blood perfusion and postoperative analysis was generated and validated for reproducibility. Laser speckle measurements were performed at 3 different time pointes, baseline (devascularized) stomach (T0), after GTR (T1), and GTR at 20° reverse Trendelenburg (T2).Blood perfusion analysis inter-rater reliability was high, with intraclass correlation coefficients for each time point approximating 1 (P generalized significant decrease in mean blood perfusion was observed across all GTR regions of interest during 20° reverse Trendelenburg (P < 0.05).It was feasible to implement LSCI intraoperatively to produce blood perfusion assessments on intact and reconstructed whole stomachs. The analytical design presented in this study resulted in good reproducibility of gastric perfusion measurements between different investigators. LSCI provides spatial and temporal information on the location of adequate tissue perfusion and may thus be an important aid in optimizing surgical and anesthesiological procedures for strategically selecting anastomotic site in patients undergoing esophagectomy with GTR. PMID:27336874

  8. Extraction of Flooded Areas due the 2015 Kanto-Tohoku Heavy Rainfall in Japan Using PALSAR-2 Images

    Science.gov (United States)

    Yamazaki, F.; Liu, W.

    2016-06-01

    Triggered by two typhoons, heavy rainfall hit Kanto and Tohoku regions of Japan from September 9 to 11, 2015. Increased river water by the continuous rainfall overflowed and destroyed several river banks and caused damaging floods in wide areas. PALSAR-2 onboard ALOS-2 satellite carried out emergency observation for the impacted areas during and after the heavy rainfall. In this study, two pre-event and four co- and post-event PALSAR-2 images were used to extract the inundation area in Joso city, Ibaraki prefecture. First, using the pre-event SAR intensity image and a detailed topographic map, the backscattering coefficient of river water was investigated. Then the flooded areas were extracted by a common threshold value of backscatter for water bodies in the six temporal images. The colour composite of the sigma naught values was also made to visualize pixels that had been converted from ground to water. Finally, the extracted results were compared with those from the visual interpretation of aerial photographs and field survey reports. This comparison revealed that the accuracy of the flood extraction was fairly good for agricultural lands and non-urban land uses. But for built-up urban areas, it was not easy to extract water body since radar illumination did to reach the ground (water) surface.

  9. Temperature-Dependent Photoluminescence Imaging and Characterization of a Multi-Crystalline Silicon Solar Cell Defect Area: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, S.; Yan, F.; Li, J.; Romero, M. J.; Al-Jassim, M.; Zaunbrecher, K.; Sidelkheir, O.; Blosse, A.

    2011-07-01

    Photoluminescence (PL) imaging is used to detect areas in multi-crystalline silicon that appear dark in band-to-band imaging due to high recombination. Steady-state PL intensity can be correlated to effective minority-carrier lifetime, and its temperature dependence can provide additional lifetime-limiting defect information. An area of high defect density has been laser cut from a multi-crystalline silicon solar cell. Both band-to-band and defect-band PL imaging have been collected as a function of temperature from ~85 to 350 K. Band-to-band luminescence is collected by an InGaAs camera using a 1200-nm short-pass filter, while defect band luminescence is collected using a 1350-nm long pass filter. The defect band luminescence is characterized by cathodo-luminescence. Small pieces from adjacent areas within the same wafer are measured by deep-level transient spectroscopy (DLTS). DLTS detects a minority-carrier electron trap level with an activation energy of 0.45 eV on the sample that contained defects as seen by imaging.

  10. Remote Sensing Image Classification Based on Decision Tree in the Karst Rocky Desertification Areas: A Case Study of Kaizuo Township

    Institute of Scientific and Technical Information of China (English)

    Shuyong; MA; Xinglei; ZHU; Yulun; AN

    2014-01-01

    Karst rocky desertification is a phenomenon of land degradation as a result of affection by the interaction of natural and human factors.In the past,in the rocky desertification areas,supervised classification and unsupervised classification are often used to classify the remote sensing image.But they only use pixel brightness characteristics to classify it.So the classification accuracy is low and can not meet the needs of practical application.Decision tree classification is a new technology for remote sensing image classification.In this study,we select the rocky desertification areas Kaizuo Township as a case study,use the ASTER image data,DEM and lithology data,by extracting the normalized difference vegetation index,ratio vegetation index,terrain slope and other data to establish classification rules to build decision trees.In the ENVI software support,we access the classification images.By calculating the classification accuracy and kappa coefficient,we find that better classification results can be obtained,desertification information can be extracted automatically and if more remote sensing image bands used,higher resolution DEM employed and less errors data reduced during processing,classification accuracy can be improve further.

  11. Large area super-resolution chemical imaging via rapid dithering of a nanoprobe

    Science.gov (United States)

    Languirand, Eric R.; Cullum, Brian M.

    2015-05-01

    Super-resolution chemical imaging via Raman spectroscopy provides a significant ability to simultaneously or pseudosimultaneously monitor numerous label-free analytes while elucidating their spatial distribution on the surface of the sample. However, spontaneous Raman is an inherently weak phenomenon making trace detection and thus superresolution imaging extremely difficult, if not impossible. To circumvent this and allow for trace detection of the few chemical species present in any sub-diffraction limited resolution element of an image, we have developed a surface enhanced Raman scattering (SERS) coherent fiber-optic imaging bundle probe consisting of 30,000 individual fiber elements. When the probes are tapered, etched and coated with metal, they provide circular Raman chemical images of a sample with a field of view of approximately 20μm (i.e. diameter) via the array of 30,000 individual 50 nm fiber elements. An acousto-optic tunable filter is used to rapidly scan or select discrete frequencies for multi- or hyperspectral analysis. Although the 50nm fiber element dimensions of this probe inherently provide spatial resolutions of approximately 100nm, further increases in the spatial resolution can be achieved by using a rapid dithering process. Using this process, additional images are obtained one-half fiber diameter translations in the x- and y- planes. A piezostage drives the movement, providing the accurate and reproducible shifts required for dithering. Optimal probability algorithms are then used to deconvolute the related images producing a final image with a three-fold increase in spatial resolution. This paper describes super-resolution chemical imaging using these probes and the dithering method as well as its potential applications in label-free imaging of lipid rafts and other applications within biology and forensics.

  12. Methodology for the detection of land cover changes in time series of daily satellite images. Application to burned area detection

    Directory of Open Access Journals (Sweden)

    J.A. Moreno-Ruiz

    2014-12-01

    Full Text Available We have developed a methodology for detection of observable phenomena at pixel level over time series of daily satellite images, based on using a Bayesian classifier. This methodology has been applied successfully to detect burned areas in the North American boreal forests using the LTDR dataset. The LTDR dataset represents the longest time series of global daily satellite images with 0.05° (~5 km of spatial resolution. The proposed methodology has several stages: 1 pre-processing daily images to obtain composite images of n days; 2 building of space of statistical variables or attributes to consider; 3 designing an algorithm, by selecting and filtering the training cases; 4 obtaining probability maps related to the considered thematic classes; 5 post-processing to improve the results obtained by applying multiple techniques (filters, ranges, spatial coherence, etc.. The generated results are analyzed using accuracy metrics derived from the error matrix (commission and omission errors, percentage of estimation and using scattering plots against reference data (correlation coefficient and slope of the regression line. The quality of the results obtained improves, in terms of spatial and timing accuracy, to other burned area products that use images of higher spatial resolution (500 m and 1 km, but they are only available after year 2000 as MCD45A1 and BA GEOLAND-2: the total burned area estimation for the study region for the years 2001-2011 was 28.56 millions of ha according to reference data and 12.41, 138.43 and 19.41 millions of ha for the MCD45A1, BA GEOLAND-2 and BA-LTDR burned area products, respectively.

  13. Sulcal variability, stereological measurement and asymmetry of Broca's area on MR images.

    Science.gov (United States)

    Keller, Simon Sean; Highley, John Robin; Garcia-Finana, Marta; Sluming, Vanessa; Rezaie, Roozbeh; Roberts, Neil

    2007-10-01

    Leftward volume asymmetry of the pars opercularis and pars triangularis may exist in the human brain, frequently referred to as Broca's area, given the functional asymmetries observed in this region with regard to language expression. However, post-mortem and magnetic resonance imaging (MRI) studies have failed to consistently identify such a volumetric asymmetry. In the present study, an analysis of the asymmetry of sulco-gyral anatomy and volume of this anterior speech region was performed in combination with an analysis of the morphology and volume asymmetry of the planum temporale, located within the posterior speech region, in 50 healthy subjects using MRI. Variations in sulcal anatomy were documented according to strict classification schemes and volume estimation of the grey matter within the brain structures was performed using the Cavalieri method of stereology. Results indicated great variation in the morphology of and connectivity between the inferior frontal, inferior precentral and diagonal sulci. There were significant inter-hemispheric differences in the presence of (1) the diagonal sulcus within the pars opercularis, and (2) horizontal termination of the posterior Sylvian fissure (relative to upward oblique termination), both with an increased leftward incidence. Double parallel inferior precentral sulci and absent anterior rami of the Sylvian fissure prevented stereological measurements in five subjects. Therefore volumes were obtained from 45 subjects. There was a significant leftward volume asymmetry of the pars opercularis (P = 0.02), which was significantly related to the asymmetrical presence of the diagonal sulcus (P < 0.01). Group-wise pars opercularis volume asymmetry did not exist when a diagonal sulcus was present in both or neither hemispheres. There was no significant volume asymmetry of the pars triangularis. There was a significant leftward volume asymmetry of the planum temporale (P < 0.001), which was significantly associated with

  14. HIGH RESOLUTION AIRBORNE SAR IMAGE CHANGE DETECTION IN URBAN AREAS WITH SLIGHTLY DIFFERENT ACQUISITION GEOMETRIES

    Directory of Open Access Journals (Sweden)

    E. Mendez Dominguez

    2015-03-01

    Full Text Available Before applying change detection, high resolution SAR (Synthetic Aperture Radar imagery benefits from advanced denoising mechanisms to preserve details and minimize speckle. We propose a change detector based on a MCA (Morphological Components Analysis of a difference image (DI. With MCA, the data is decomposed into image features utilizing sparse representations of the image content. By introducing a priori knowledge of the content of the scenes, and exploiting shape information corresponding to the changes provided by MCA, we can significantly improve performance under adverse conditions, such as inconsistent acquisition geometries.

  15. A Fieldable-Prototype Large-Area Gamma-ray Imager for Orphan Source Search

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, Klaus-Peter [ORNL; Fabris, Lorenzo [ORNL; Carr, Dennis [Lawrence Livermore National Laboratory (LLNL); Collins, Jeff [Lawrence Livermore National Laboratory (LLNL); Cunningham, Mark F [Lawrence Livermore National Laboratory (LLNL); Habte Ghebretatios, Frezghi [ORNL; Karnowski, Thomas Paul [ORNL; Marchant, William [University of California, Berkeley

    2008-01-01

    We have constructed a unique instrument for use in the search for orphan sources. The system uses gamma-ray imaging to "see through" the natural background variations that effectively limit the search range of normal devices to ~10 m. The imager is mounted in a 4.9- m-long trailer and can be towed by a large personal vehicle. Source locations are determined both in range and along the direction of travel as the vehicle moves. A fully inertial platform coupled to a Global Positioning System receiver is used to map the gamma-ray images onto overhead geospatial imagery. The resulting images provide precise source locations, allowing rapid follow-up work. The instrument simultaneously searches both sides of the street to a distance of 50 m (100-m swath) for milliCurieclass sources with near-perfect performance.

  16. Facility for low-dose digital scanning of a large-area image of ionizing radiation

    International Nuclear Information System (INIS)

    The facility scans the unreduced X-ray image by means of moving line sensors which work in parallel. The length of the sensors is much smaller than the width of the image. The facility comprises about 20 identical modules, owing to which the output of the serial manufacture can be increased, and CCD-based line sensors can be employed which are very sensitive and inexpensive. The X-ray image can be taken at the virtually lowest exposure possible, and owing to the parallelization of the scanning process, the scanning rate can be increased considerably as compared with the existing facilities. The facility consists of an ionizing radiation source against which are positioned a movable diaphragm fitted with slits and a movable support plate carrying the line sensors. The sensors make up the line detector whose length is equal to that of the image scanned, synchronously movable with the movable slit diaphragm. (M.D.). 3 figs

  17. Progress in BazookaSPECT: High-Resolution, Dynamic Scintigraphy with Large-Area Imagers

    OpenAIRE

    Miller, Brian W.; Barber, H. Bradford; Barrett, Harrison H.; Liu, Zhonglin; Nagarkar, Vivek V.; Furenlid, Lars R.

    2012-01-01

    We present recent progress in BazookaSPECT, a high-resolution, photon-counting gamma-ray detector. It is a new class of scintillation detector that combines columnar scintillators, image intensifiers, and CCD (charge-coupled device) or CMOS (complementary metal-oxide semiconductors) sensors for high-resolution imaging. A key feature of the BazookaSPECT paradigm is the capability to easily design custom detectors in terms of the desired intrinsic detector resolution and event detection rate. T...

  18. Representation of perceptually invisible image motion in extrastriate visual area MT of macaque monkeys.

    Science.gov (United States)

    Hohl, Sonja S; Lisberger, Stephen G

    2011-11-16

    Why does the world appear stable despite the visual motion induced by eye movements during fixation? We find that the answer must reside in how visual motion signals are interpreted by perception, because MT neurons in monkeys respond to the image motion caused by eye drifts in the presence of a stationary stimulus. Several features suggest a visual origin for the responses of MT neurons during fixation: spike-triggered averaging yields a peak image velocity in the preferred direction that precedes spikes by ∼60 ms; image velocity during fixation and firing rate show similar peaks in power at 4-5 Hz; and average MT firing during a period of fixation is related monotonically to the image speed along the preferred axis of the neurons 60 ms earlier. The percept caused by the responses of MT neurons during fixation depends on the distribution of activity across the population of neurons of different preferred speeds. For imposed stimulus motion, the population response peaks for neurons that prefer the actual target speed. For small image motions caused by eye drifts during fixation, the population response is large, but is noisy and does not show a clear peak. This representation of image motion in MT would be ignored if perception interprets the population response in the context of a prior of zero speed. Then, we would see a stable scene despite MT responses caused by eye drifts during fixation. PMID:22090483

  19. Comparison of remote sensing image processing techniques to identify tornado damage areas from Landsat TM data

    Science.gov (United States)

    Myint, S.W.; Yuan, M.; Cerveny, R.S.; Giri, C.P.

    2008-01-01

    Remote sensing techniques have been shown effective for large-scale damage surveys after a hazardous event in both near real-time or post-event analyses. The paper aims to compare accuracy of common imaging processing techniques to detect tornado damage tracks from Landsat TM data. We employed the direct change detection approach using two sets of images acquired before and after the tornado event to produce a principal component composite images and a set of image difference bands. Techniques in the comparison include supervised classification, unsupervised classification, and objectoriented classification approach with a nearest neighbor classifier. Accuracy assessment is based on Kappa coefficient calculated from error matrices which cross tabulate correctly identified cells on the TM image and commission and omission errors in the result. Overall, the Object-oriented Approach exhibits the highest degree of accuracy in tornado damage detection. PCA and Image Differencing methods show comparable outcomes. While selected PCs can improve detection accuracy 5 to 10%, the Object-oriented Approach performs significantly better with 15-20% higher accuracy than the other two techniques. ?? 2008 by MDPI.

  20. Images

    Data.gov (United States)

    National Aeronautics and Space Administration — Images for the website main pages and all configurations. The upload and access points for the other images are: Website Template RSW images BSCW Images HIRENASD...

  1. LEAF AREA INDEX ESTIMATION IN VINEYARDS FROM UAV HYPERSPECTRAL DATA, 2D IMAGE MOSAICS AND 3D CANOPY SURFACE MODELS

    OpenAIRE

    I. Kalisperakis; Stentoumis, Ch.; L. Grammatikopoulos; K. Karantzalos

    2015-01-01

    The indirect estimation of leaf area index (LAI) in large spatial scales is crucial for several environmental and agricultural applications. To this end, in this paper, we compare and evaluate LAI estimation in vineyards from different UAV imaging datasets. In particular, canopy levels were estimated from i.e., (i) hyperspectral data, (ii) 2D RGB orthophotomosaics and (iii) 3D crop surface models. The computed canopy levels have been used to establish relationships with the measured ...

  2. Intra-Rater Reliability of Rehabilitative Ultrasound Imaging for Multifidus Muscles Thickness and Cross Section Area in Healthy Subjects

    OpenAIRE

    Hosseinifar, Mohammad; Akbari, Asghar; Ghiasi, Fateme

    2015-01-01

    Introduction: Rehabilitative Ultrasound Imaging (RUSI) must be valuable method for research and rehabilitation. So, the reliability of its measurements must be determined. The purpose of this study was to evaluate the intra-rater reliability of RUSI for measurement of multifidus (MF) muscles cross section areas (CSAs), bladder wall diameter, and thickness of MF muscles between 2 sessions in healthy subjects. Method: Fifteen healthy subjects through simple non-probability sampling participated...

  3. Hot embossing holographic images in BOPP shrink films through large-area roll-to-roll nanoimprint lithography

    International Nuclear Information System (INIS)

    Highlights: • High-quality holographic images were replicated in large-area shrink film. • Surface morphology evolution was analyzed in films embossed at different temperatures. • Optical, mechanical, and thermal characteristics were systematically analyzed. - Abstract: Diffraction grating-based holographic images have been successfully replicated in biaxially oriented polypropylene (BOPP) shrink films through large-area roll-to-roll nanoimprint technique. Such hot embossing of holographic images on BOPP films represents a promising means of creating novel security features in packaging applications. The major limitation of the high-quality replication is the relatively large thermal shrinkage of BOPP shrink film. However, although an appropriate shrinkage is demanded after embossing, over-shrinking not only causes distortion in embossed images, but also reduces the various properties of BOPP shrink films mainly due to the disappearance of orientation. The effects of embossing temperature on the mechanical, thermal and optical properties as well as polymer surface morphologies were systematically analyzed. The results show that the optimal process parameters are listed as follows: the embossing temperature at 104–110 °C, embossing force 6 kg/cm2 and film speed 32 m/min. The variation in flow behavior of polymer surface during hot embossing process is highly dependent on the temperature. In addition, the adhesion from the direct contact between the rubber press roller and polymer surfaces is suggested to cause the serious optical properties failure

  4. Hot embossing holographic images in BOPP shrink films through large-area roll-to-roll nanoimprint lithography

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Menglin; Lin, Shiwei, E-mail: linsw@hainu.edu.cn; Jiang, Wenkai; Pan, Nengqian

    2014-08-30

    Highlights: • High-quality holographic images were replicated in large-area shrink film. • Surface morphology evolution was analyzed in films embossed at different temperatures. • Optical, mechanical, and thermal characteristics were systematically analyzed. - Abstract: Diffraction grating-based holographic images have been successfully replicated in biaxially oriented polypropylene (BOPP) shrink films through large-area roll-to-roll nanoimprint technique. Such hot embossing of holographic images on BOPP films represents a promising means of creating novel security features in packaging applications. The major limitation of the high-quality replication is the relatively large thermal shrinkage of BOPP shrink film. However, although an appropriate shrinkage is demanded after embossing, over-shrinking not only causes distortion in embossed images, but also reduces the various properties of BOPP shrink films mainly due to the disappearance of orientation. The effects of embossing temperature on the mechanical, thermal and optical properties as well as polymer surface morphologies were systematically analyzed. The results show that the optimal process parameters are listed as follows: the embossing temperature at 104–110 °C, embossing force 6 kg/cm{sup 2} and film speed 32 m/min. The variation in flow behavior of polymer surface during hot embossing process is highly dependent on the temperature. In addition, the adhesion from the direct contact between the rubber press roller and polymer surfaces is suggested to cause the serious optical properties failure.

  5. InSAR imaging of volcanic deformation over cloud-prone areas - Aleutian islands

    Science.gov (United States)

    Lu, Zhong

    2007-01-01

    Interferometric synthetic aperture radar (INSAR) is capable of measuring ground-surface deformation with centimeter-tosubcentimeter precision and spatial resolution of tens-of meters over a relatively large region. With its global coverage and all-weather imaging capability, INSAR is an important technique for measuring ground-surface deformation of volcanoes over cloud-prone and rainy regions such as the Aleutian Islands, where only less than 5 percent of optical imagery is usable due to inclement weather conditions. The spatial distribution of surface deformation data, derived from INSAR images, enables the construction of detailed mechanical models to enhance the study of magmatic processes. This paper reviews the basics of INSAR for volcanic deformation mapping and the INSAR studies of ten Aleutian volcanoes associated with both eruptive and noneruptive activity. These studies demonstrate that all-weather INSAR imaging can improve our understanding of how the Aleutian volcanoes work and enhance our capability to predict future eruptions and associated hazards.

  6. Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This DS consists of the locally enhanced ALOS image mosaics for each of the 24 mineral project areas (referred to herein as areas of interest), whose locality names, locations, and main mineral occurrences are shown on the index map of Afghanistan (fig. 1). ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency, but the image processing has altered the original pixel structure and all image values of the JAXA

  7. Preoperative 3T high field blood oxygen level dependent functional magnetic resonance imaging for glioma involving sensory cortical areas

    Institute of Scientific and Technical Information of China (English)

    LI Shao-wu; WANG Jiang-fei; JIANG Tao; LI Shou-wei; ZHANG Wen-bo; LI Zi-xiao; ZHANG Zhong; DAI Jian-ping; WANG Zhong-cheng

    2010-01-01

    Background Localization of sensory cortical areas during the operation is essential to preserve the sensory function.Intraoperative direct electrostimulation under awake anesthesia is the golden standard but time-consuming. We applied 3T high field blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to identify the relationship between glioma and cortical sensory areas preoperatively and to guide intraoperative direct electrostimulation for quick and precise localization.Methods Five glioma patients with sensory cortex involvement by or next to the lesion had preoperative BOLD fMRI to determine the spatial relationship of cortical sensory areas to the tumours. Bilateral hand opposite movement was performed by these patients for fMRI. Precentral and postcentral gyri were identified by electrical stimulation during the operation. Karnofsky Performance Status scores of the patients' pre- and postoperative and the role of BOLD fMRI were evaluated.Results The cortical sensory areas were all activated in five glioma patients involving postcentral gyrus areas by BOLDf MRI with bilateral hand opposite movement. The detected activation areas corresponded with the results from cortical electrical stimulation.Conclusions The relationship between cortical sensory areas and tumour can be accurately shown by BOLD fMRI before operation. And the information used to make the tumour resection could obtain good clinical results.

  8. Refinement Method for Residential Area Revision Using Remote Sensing Image and GIS Data in Earthquake Risk Assessment

    Science.gov (United States)

    Dou, A. X.; Yuan, X. X.; Wang, X. Q.; Li, Z. M.

    2016-06-01

    This paper proposes an automatic approach for residential areas revision by means of analysing the correlation between the residential area and the topographic and geographical factors. The approach consists of four major steps: the extracting of missing residential area from the remote sensing images with high resolution; the statistic analysing on the size changes of missing residential area in each grade of the elevation, slope, distance from the road and other impact factors; modelling of residential area modification in the urban and rural region; testing the methods using 100 counties data which are located in the middle part of China North-South Seismic Belt and comparing the result to the Land Use in map scale 1:100000. The experimental results present the accuracy of urban residents by 70% increased to 89.4%, rural residents by 47% up to 81.9%, rural residents from 8% increased to 78.5%. Therefore, there is available risk exposure information in a sparsely populated area because the spatial grid distributions of population and buildings are based on the residential areas. The proposed approach in this paper will improve the accuracy of the seismic risk assessment if it is applied to the national or the whole world.

  9. A high-speed area detector for novel imaging techniques in a scanning transmission electron microscope.

    Science.gov (United States)

    Caswell, T A; Ercius, P; Tate, M W; Ercan, A; Gruner, S M; Muller, D A

    2009-03-01

    A scanning transmission electron microscope (STEM) produces a convergent beam electron diffraction pattern at each position of a raster scan with a focused electron beam, but recording this information poses major challenges for gathering and storing such large data sets in a timely manner and with sufficient dynamic range. To investigate the crystalline structure of materials, a 16x16 analog pixel array detector (PAD) is used to replace the traditional detectors and retain the diffraction information at every STEM raster position. The PAD, unlike a charge-coupled device (CCD) or photomultiplier tube (PMT), directly images 120-200keV electrons with relatively little radiation damage, exhibits no afterglow and limits crosstalk between adjacent pixels. Traditional STEM imaging modes can still be performed by the PAD with a 1.1kHz frame rate, which allows post-acquisition control over imaging conditions and enables novel imaging techniques based on the retained crystalline information. Techniques for rapid, semi-automatic crystal grain segmentation with sub-nanometer resolution are described using cross-correlation, sub-region integration, and other post-processing methods. PMID:19162398

  10. Functional magnetic resonance imaging connectivity analyses reveal efference-copy to primary somatosensory area, BA2

    NARCIS (Netherlands)

    Cui, Fang; Arnstein, Dan; Thomas, Rajat Mani; Maurits, Natasha M; Keysers, C.; Gazzola, Valeria

    2014-01-01

    Some theories of motor control suggest efference-copies of motor commands reach somatosensory cortices. Here we used functional magnetic resonance imaging to test these models. We varied the amount of efference-copy signal by making participants squeeze a soft material either actively or passively.

  11. Functional Magnetic Resonance Imaging Connectivity Analyses Reveal Efference-Copy to Primary Somatosensory Area, BA2

    NARCIS (Netherlands)

    Cui, Fang; Arnstein, Dan; Thomas, Rajat Mani; Maurits, Natasha M.; Keysers, Christian; Gazzola, Valeria

    2014-01-01

    Some theories of motor control suggest efference-copies of motor commands reach somatosensory cortices. Here we used functional magnetic resonance imaging to test these models. We varied the amount of efference-copy signal by making participants squeeze a soft material either actively or passively.

  12. Applying of Electrical Imaging Survey (EIS) to Evaluate Leachate Pollution in Underground Area of Informal Landfill

    DEFF Research Database (Denmark)

    Du, Song; Wang, Di; Mou, Zishen;

    2014-01-01

    An informal landfill is an open dump that pollutes the underground environment because it lacks an impervious liner. The leakage of such a landfill is unidirectional and thus difficult to directly test. This study uses electrical imaging survey to evaluate the pollution of the underground environ...

  13. Lake Urmia Shrinkage and its Effect on the Settlement of the Surrounding Areas Investigated Using Radar and Optical Satellite Images

    Science.gov (United States)

    Motagh, M.; Shamshiri, R.; Hosseini, F.; Sharifi, M. A.; Baes, M.

    2014-12-01

    With a total area of more than 50000 km^2 Lake Urmia basin in northwest of Iran was once one of the biggest salt lakes in the world. The lake has been shrinking in the recent years, losing in turn dramatically its area. A lot of factors have been attributed to this shrinking including construction of dams on the rivers feeding the lake and overexploitation of groundwater for agricultural and industrial purposes. In this study we first utilized time-series analysis of Landsat images to precisely quantify surface changes in the region between 1984 and 2013. We then analyzed a number of SAR images from 2002 to 2014 including 30 ASAR images from Envisat, 10 PALSAR images from ALOS, and more than 35 TerraSAR-X (TSX) in both Stripmap and Spot modes to assess surface ground deformation. Ground deformation was evaluated for both agricultural regions around the lake and Lake Urmia Causeway (LUC), connecting two provinces of East and West Azerbaijan on both sides of the lake. The InSAR results of the LUC embankments is further investigated using Finite Element approach to better understand the relation between soil parameters, lake level changes and settlement of the LUC. The classification results using optical imagery analysis show that human and anthropogenic activities have resulted in shrinking of Lake Urmia by more than 60% over the past 30 years. The agricultural areas around the lake are dominated by ground subsidence reaching to 10 cm/yr in places. The LUC embankments also show large deformation with peak settlement of more than 5 cm/yr over the last decade. FEM simulation shows that consolidation due to dissipation of excess pore pressure in embankments can satisfactorily explain its surface deformation.

  14. Quality of Life Assessment Based on Spatial and Temporal Analysis of the Vegetation Area Derived from Satellite Images

    Directory of Open Access Journals (Sweden)

    MARIA IOANA VLAD

    2011-01-01

    Full Text Available The quality of life in urban areas is a function of many parameters among which, one highly important is the number and quality of green areas for people and wildlife to thrive. The quality of life is also a political concept often used to describe citizen satisfaction within different residential locations. Only in the last decades green areas have suffered a progressive decrease in quality, pointing out the ecological urban risk with a negative impact on the standard of living and population health status. This paper presents the evolution of green areas in the cities of South-Eastern Romania within the last 20 years and sets forth the current state of quality of life from the perspective of vegetation reference. By using state-of-the-art processing tools applied on high-resolution satellite images, we have derived knowledge about the spatial and temporal expansion of urbanized regions. Our semi-automatic technologies for analysis of remote sensing data such as Landsat 7 ETM+, correlated with statistical information inferred from urban charts, demonstrate a negative trend in the distribution of green areas within the analyzed cities, with long-term implications on multiple areas in our lives.

  15. NIR area array CCD-based singlet oxygen luminescence imaging for photodynamic therapy

    International Nuclear Information System (INIS)

    In this work, a near-infrared CCD-based singlet oxygen luminescence two-dimensional imaging method is proposed to detect singlet oxygen by its 1270nm luminescence. Two-dimensional singlet oxygen images with its near-infrared luminescence during photosensitization could be obtained with a CCD integration time of 1s, without scanning. The data presented shows a linear relationship between the singlet oxygen luminescence intensity and sample concentration. This method provides a detection sensitivity of 0.00189mg/ml (Hematoporphyrin monomethyl Ether dissolved in ethanol) and a spatial resolution better than 100μm. We applied this method in vivo to demonstrate its potential in monitoring photodynamic therapy.

  16. MONITORING GROUND SUBSIDENCE IN AREAS COVERED BY DENSE VEGETATION USING TERRASAR-X IMAGES: A CASE STUDY OF HANGZHOU

    Directory of Open Access Journals (Sweden)

    H. A. Wu

    2016-06-01

    Full Text Available Hangzhou, the capital of Zhejiang province has suffered serious ground subsidence during the past several decades, due to long term over-exploration of groundwater. In this paper, the time series InSAR technique using high resolution SAR images is investigated for the generation of subsidence maps over Hangzhou region. 29 TerraSAR-X images acquired from May 2012 to Sep 2015 are used. The results show that serious subsidence has mainly taken place in suburban area, including Yuhang district, Xiaoshan district and Binjiang district. 4 subsidence centers are discovered, namely Tangqi town in Yuhang with an average subsiding velocity of -29.6 mm/year, Xintang (-30.7 mm/year in Xiaoshan, Zhujiaqiao town (-25.6mm/year in Xiaoshan, and Miaohouwang town (-30.1mm/year in Binjiang. The urban area is stable and ground rebound even take place in some places. The results are compared with 19 levelling measurements. The RMS error between them is 2.9 mm/year, which demonstrates that the high resolution TerraSAR-X images has good accuracy for subsidence monitoring in the southeast of China, covered by dense vegetation.

  17. Monitoring Ground Subsidence in Areas Covered by Dense Vegetation Using Terrasar-X Images: a Case Study of Hangzhou

    Science.gov (United States)

    Wu, H. A.; Zhang, Y. H.; Luo, G. F.; Kang, Y. K.; Zhu, Y. M.

    2016-06-01

    Hangzhou, the capital of Zhejiang province has suffered serious ground subsidence during the past several decades, due to long term over-exploration of groundwater. In this paper, the time series InSAR technique using high resolution SAR images is investigated for the generation of subsidence maps over Hangzhou region. 29 TerraSAR-X images acquired from May 2012 to Sep 2015 are used. The results show that serious subsidence has mainly taken place in suburban area, including Yuhang district, Xiaoshan district and Binjiang district. 4 subsidence centers are discovered, namely Tangqi town in Yuhang with an average subsiding velocity of -29.6 mm/year, Xintang (-30.7 mm/year) in Xiaoshan, Zhujiaqiao town (-25.6mm/year) in Xiaoshan, and Miaohouwang town (-30.1mm/year) in Binjiang. The urban area is stable and ground rebound even take place in some places. The results are compared with 19 levelling measurements. The RMS error between them is 2.9 mm/year, which demonstrates that the high resolution TerraSAR-X images has good accuracy for subsidence monitoring in the southeast of China, covered by dense vegetation.

  18. A voxel-wise encoding model for early visual areas decodes mental images of remembered scenes.

    Science.gov (United States)

    Naselaris, Thomas; Olman, Cheryl A; Stansbury, Dustin E; Ugurbil, Kamil; Gallant, Jack L

    2015-01-15

    Recent multi-voxel pattern classification (MVPC) studies have shown that in early visual cortex patterns of brain activity generated during mental imagery are similar to patterns of activity generated during perception. This finding implies that low-level visual features (e.g., space, spatial frequency, and orientation) are encoded during mental imagery. However, the specific hypothesis that low-level visual features are encoded during mental imagery is difficult to directly test using MVPC. The difficulty is especially acute when considering the representation of complex, multi-object scenes that can evoke multiple sources of variation that are distinct from low-level visual features. Therefore, we used a voxel-wise modeling and decoding approach to directly test the hypothesis that low-level visual features are encoded in activity generated during mental imagery of complex scenes. Using fMRI measurements of cortical activity evoked by viewing photographs, we constructed voxel-wise encoding models of tuning to low-level visual features. We also measured activity as subjects imagined previously memorized works of art. We then used the encoding models to determine if putative low-level visual features encoded in this activity could pick out the imagined artwork from among thousands of other randomly selected images. We show that mental images can be accurately identified in this way; moreover, mental image identification accuracy depends upon the degree of tuning to low-level visual features in the voxels selected for decoding. These results directly confirm the hypothesis that low-level visual features are encoded during mental imagery of complex scenes. Our work also points to novel forms of brain-machine interaction: we provide a proof-of-concept demonstration of an internet image search guided by mental imagery.

  19. Amorphous Silicon p-i-n Structure Acting as Light and Temperature Sensor

    Directory of Open Access Journals (Sweden)

    Giampiero de Cesare

    2015-05-01

    Full Text Available In this work, we propose a multi-parametric sensor able to measure both temperature and radiation intensity, suitable to increase the level of integration and miniaturization in Lab-on-Chip applications. The device is based on amorphous silicon p-doped/intrinsic/n-doped thin film junction. The device is first characterized as radiation and temperature sensor independently. We found a maximum value of responsivity equal to 350 mA/W at 510 nm and temperature sensitivity equal to 3.2 mV/K. We then investigated the effects of the temperature variation on light intensity measurement and of the light intensity variation on the accuracy of the temperature measurement. We found that the temperature variation induces an error lower than 0.55 pW/K in the light intensity measurement at 550 nm when the diode is biased in short circuit condition, while an error below 1 K/µW results in the temperature measurement when a forward bias current higher than 25 µA/cm2 is applied.

  20. Large area CMOS active pixel sensor x-ray imager for digital breast tomosynthesis: Analysis, modeling, and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chumin; Kanicki, Jerzy, E-mail: kanicki@eecs.umich.edu [Solid-State Electronics Laboratory, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Konstantinidis, Anastasios C. [Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom and Diagnostic Radiology and Radiation Protection, Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester M20 4BX (United Kingdom); Patel, Tushita [Department of Physics, University of Virginia, Charlottesville, Virginia 22908 (United States)

    2015-11-15

    Purpose: Large area x-ray imagers based on complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) technology have been proposed for various medical imaging applications including digital breast tomosynthesis (DBT). The low electronic noise (50–300 e{sup −}) of CMOS APS x-ray imagers provides a possible route to shrink the pixel pitch to smaller than 75 μm for microcalcification detection and possible reduction of the DBT mean glandular dose (MGD). Methods: In this study, imaging performance of a large area (29 × 23 cm{sup 2}) CMOS APS x-ray imager [Dexela 2923 MAM (PerkinElmer, London)] with a pixel pitch of 75 μm was characterized and modeled. The authors developed a cascaded system model for CMOS APS x-ray imagers using both a broadband x-ray radiation and monochromatic synchrotron radiation. The experimental data including modulation transfer function, noise power spectrum, and detective quantum efficiency (DQE) were theoretically described using the proposed cascaded system model with satisfactory consistency to experimental results. Both high full well and low full well (LFW) modes of the Dexela 2923 MAM CMOS APS x-ray imager were characterized and modeled. The cascaded system analysis results were further used to extract the contrast-to-noise ratio (CNR) for microcalcifications with sizes of 165–400 μm at various MGDs. The impact of electronic noise on CNR was also evaluated. Results: The LFW mode shows better DQE at low air kerma (K{sub a} < 10 μGy) and should be used for DBT. At current DBT applications, air kerma (K{sub a} ∼ 10 μGy, broadband radiation of 28 kVp), DQE of more than 0.7 and ∼0.3 was achieved using the LFW mode at spatial frequency of 0.5 line pairs per millimeter (lp/mm) and Nyquist frequency ∼6.7 lp/mm, respectively. It is shown that microcalcifications of 165–400 μm in size can be resolved using a MGD range of 0.3–1 mGy, respectively. In comparison to a General Electric GEN2 prototype DBT system (at

  1. MR imaging changes in the trochanteric area of asymptomatic individuals: A potential for misdiagnosis of pain in the trochanteric region

    Energy Technology Data Exchange (ETDEWEB)

    De Maeseneer, Michel [Department of Radiology, Wake Forest University Hospital, Medical Center Boulevard, Winston Salem, NC 27157 (United States)], E-mail: mdemaes2@wfubmc.edu; Gosselin, Robert [Department of Radiology, Universiteit Gent, Ghent (Belgium); De Ridder, Fillip; Shahabpour, Maryam; Vanderdood, Kurt [Department of Radiology, Vrije Universiteit Brussel, Brussels (Belgium)

    2009-12-15

    Objective: To investigate the MR imaging appearance of the trochanteric region in a group of patients referred for non-musculoskeletal conditions. Materials and methods: Forty-five patients (n = 90 hips) referred for non-musculoskeletal conditions were imaged with a coronal T1 weighted fat saturated sequence after intravenous administration of contrast medium. Findings were interpreted by consensus of two experienced radiologists. Results: In 54 of 90 hips (60%) no signal changes were seen at the level of the greater trochanter. A linear area of contrast enhancement with a craniocaudal dimension of less than 3 cm, and thickness less than 0.3 cm was seen in 32 of 90 hips (35.6%). A fusiform area of contrast enhancement with a craniocaudal dimension of more than 3 cm, and thickness more than 0.3 cm was seen in 4 hips (4.4%). Conclusion: An area of signal abnormality may be seen on contrast enhanced studies in asymptomatic persons, located in between the gluteus medius tendon and iliotibial band, and this should not be considered as a cause of pain in the trochanteric region.

  2. Comparative analysis for detecting areas with building damage from several destructive earthquakes using satellite synthetic aperture radar images

    Science.gov (United States)

    Matsuoka, Masashi; Yamazaki, Fumio

    2010-11-01

    Earthquakes that have caused large-scale damage in developed areas, such as the 1994 Northridge and 1995 Kobe events, remind us of the importance of making quick damage assessments in order to facilitate the resumption of normal activities and restoration planning. Synthetic aperture radar (SAR) can be used to record physical aspects of the Earth's surface under any weather conditions, making it a powerful tool in the development of an applicable method for assessing damage following natural disasters. Detailed building damage data recorded on the ground following the 1995 Kobe earthquake may provide an invaluable opportunity to investigate the relationship between the backscattering properties and the degree of damage. This paper aims to investigate the differences between the backscattering coefficients and the correlations derived from pre- and post-earthquake SAR intensity images to smoothly detect areas with building damage. This method was then applied to SAR images recorded over the areas affected by the 1999 Kocaeli earthquake in Turkey, the 2001 Gujarat earthquake in India, and the 2003 Boumerdes earthquake in Algeria. The accuracy of the proposed method was examined and confirmed by comparing the results of the SAR analyses with the field survey data.

  3. Calculation of area-averaged vertical profiles of the horizontal wind velocity from volume-imaging lidar data

    Science.gov (United States)

    Schols, J. L.; Eloranta, E. W.

    1992-01-01

    Area-averaged horizontal wind measurements are derived from the motion of spatial inhomogeneities in aerosol backscattering observed with a volume-imaging lidar. Spatial averaging provides high precision, reducing sample variations of wind measurements well below the level of turbulent fluctuations, even under conditions of very light mean winds and strong convection or under the difficult conditions represented by roll convection. Wind velocities are measured using the two-dimensional spatial cross correlation computed between successive horizontal plane maps of aerosol backscattering, assembled from three-dimensional lidar scans. Prior to calculation of the correlation function, three crucial steps are performed: (1) the scans are corrected for image distortion by the wind during a finite scan time; (2) a temporal high pass median filtering is applied to eliminate structures that do not move with the wind; and (3) a histogram equalization is employed to reduce biases to the brightest features.

  4. Quantitative Magnetic Resonance Imaging of Brainstem Volumes, Plaques, and Surface Area in the Occipital Regions of Patients with Multiple Sclerosis

    International Nuclear Information System (INIS)

    Purpose: To determine brainstem volumes, number of plaques, and surface areas in the occipital lobes of patients with relapsing remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS), and to investigate whether there is any correlation between brainstem volume and the number/surface areas of plaque in the occipital lobes. Material and Methods: Magnetic resonance imaging was obtained on 14 relapsing-remitting (RR) and 13 secondary progressive (SP) MS patients and 26 female control subjects. The Cavalieri method was used by modern design stereology to measure brainstem volume. The point-counting grid was used to evaluate sclerotic plaque surface areas in the occipital lobe. The number of plaques in the imaging section was calculated. Results: Brainstem volumes for RR and SP with multiple sclerosis and control subjects were 3647 mm3 , 3515 mm3 , and 4517 mm3 , respectively. Mean number of plaques in the right-left occipital lobe was found to be 2.7-3.4 in RR-MS and 5.2-2.8 in SP-MS. Mean plaque surface area in the right-left occipital lobe was determined to be 58.52-88.24 mm2 in RR MS and 124.3-64.82 mm2 in SP MS. Brainstem volumes were significantly reduced in both groups of patients with MS compared to controls ( P <0.01). Conclusion: Magnetic-resonance-estimated volume and surface area values in multiple sclerosis may facilitate our understanding of the clinical situation of patients and provide a simple index for evaluating therapeutic efficiency

  5. Quantitative Magnetic Resonance Imaging of Brainstem Volumes, Plaques, and Surface Area in the Occipital Regions of Patients with Multiple Sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Alper, F.; Kantarci, M.; Altunkaynak, E.; Varoglu, A. O.; Karaman, A.; Oral, E.; Okur, A. [Ataturk Univ., Erzurum (Turkey). Depts. of Radiology, Histology, Neurology and Embryology, Psychiatry

    2006-07-15

    Purpose: To determine brainstem volumes, number of plaques, and surface areas in the occipital lobes of patients with relapsing remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS), and to investigate whether there is any correlation between brainstem volume and the number/surface areas of plaque in the occipital lobes. Material and Methods: Magnetic resonance imaging was obtained on 14 relapsing-remitting (RR) and 13 secondary progressive (SP) MS patients and 26 female control subjects. The Cavalieri method was used by modern design stereology to measure brainstem volume. The point-counting grid was used to evaluate sclerotic plaque surface areas in the occipital lobe. The number of plaques in the imaging section was calculated. Results: Brainstem volumes for RR and SP with multiple sclerosis and control subjects were 3647 mm{sup 3} , 3515 mm{sup 3} , and 4517 mm{sup 3} , respectively. Mean number of plaques in the right-left occipital lobe was found to be 2.7-3.4 in RR-MS and 5.2-2.8 in SP-MS. Mean plaque surface area in the right-left occipital lobe was determined to be 58.52-88.24 mm{sup 2} in RR MS and 124.3-64.82 mm{sup 2} in SP MS. Brainstem volumes were significantly reduced in both groups of patients with MS compared to controls ( P <0.01). Conclusion: Magnetic-resonance-estimated volume and surface area values in multiple sclerosis may facilitate our understanding of the clinical situation of patients and provide a simple index for evaluating therapeutic efficiency.

  6. Researches on the Land-Use Change Detection of Mine Area Based on Tm/etm Images

    Science.gov (United States)

    Qin, Y.; Liling, H.; Min, Y.; Yi, L.

    2013-07-01

    With the economic development and population growth, land use status is changing rapidly in Chinese urban. Since the remote sensing technology can analyze and detect the land use information quickly and accurately, it has been widely applied to obtain the land use/land cover change (LUCC) information today. The land surface destroy occurred in mineral resources exploration will result in a lot of environmental problems in coal mine areas. But there are few research in small and medium-sized cities and coal mine areas. So Peixian is used as the study area in the paper. The Landsat TM/ETM images spanning 3 years and thematic map are adopted to detect the land-use change of the area. In order to improve the classification results, we built an optimized classification model adapting classic SVM method, which was defined "a feature weighted SVM classifier using mixed kernel function". Based on geostatistic and multi-scale statistical knowledge, we calculated the transformation matrix and dynamic index of land-use types, from which we conducted quantitative analysis and the driving force on the mine land-use change of Peixian. Then, we can achieve resource dynamic change detection of four years in Peixian area, analyze the effect of the surface land-use change due to mineral exploration and obtain the causes of land-use change.

  7. Water-Body Area Extraction from High Resolution Satellite Images-An Introduction, Review, and Comparison

    Directory of Open Access Journals (Sweden)

    Rajiv Kumar Nath

    2010-01-01

    Full Text Available Water resources play an important role in environmental, transportation andregion planning, natural disaster, industrial and agricultural production and so on.Surveying of water-bodies and delineate its features properly is very first stepfor any planning, especially for places like India, where the land-cover isdominated by water-bodies. Recording images, such as from satellite, sometimesdoes not reflect the distinguished characteristics of water with non-waterfeatures, e.g. shadows of super structures. Image of water body is confusedeasily with the shadow of skyscraper, since calm water surface induces mirrorreflection when it gives birth to echo wave. Water transport is cheapest.Developing/poor countries like India will be benifitted if water transport isencouraged. In water transport, the link should be made between various landmasses, including building blocks, through proper navigational system. Hencethere should be clear distinction between calm water and the shadows ofbuildings. Over the past decade, a significant amount of research beenconducted to extract the water body information from various multi-resolutionsatellite images. The objective of this paper is to review methodologies appliedfor water body extraction using satellite remote sensing. The GeographicInformation System (GIS and the Global Positioning System (GPS have alsobeen discussed as they are closely linked with Remote Sensing. Initially, studieson water body detection are treated. Methodological issues related to the use ofthese methods were analysed followed by summaries. Results from empiricalstudies, applying water-body extraction techniques are collected and discussed.Important issues for future research are also identified and discussed.

  8. Vapor transport deposition of large-area polycrystalline CdTe for radiation image sensor application

    International Nuclear Information System (INIS)

    Vapor transport deposition (VTD) process delivers saturated vapor to substrate, resulting in high-throughput and scalable process. In addition, VTD can maintain lower substrate temperature than close-spaced sublimation (CSS). The motivation of this work is to adopt several advantages of VTD for radiation image sensor application. Polycrystalline CdTe films were obtained on 300 mm x 300 mm indium tin oxide (ITO) coated glass. The polycrystalline CdTe film has columnar structure with average grain size of 3 μm ∝ 9 μm, which can be controlled by changing the substrate temperature. In order to analyze electrical and X-ray characteristics, ITO-CdTe-Al sandwich structured device was fabricated. Effective resistivity of the polycrystalline CdTe film was ∝1.4 x 109Ωcm. The device was operated under hole-collection mode. The responsivity and the μτ product estimated to be 6.8 μC/cm2R and 5.5 x 10-7 cm2/V. The VTD can be a process of choice for monolithic integration of CdTe thick film for radiation image sensor and CMOS/TFT circuitry. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Tomographic Imaging of Jakarta Area from Cross-correlation of Seismic Ambient Noise

    Science.gov (United States)

    Pranata, B.; Saygin, E.; Cummins, P. R.; Widiyantoro, S.; Nugraha, A. D.; Harjadi, P.; Suhardjono, S.

    2012-12-01

    Seismic imaging of sediment thickness of Jakarta is crucial where Jakarta city is currently being rapidly developed with major installations and high-rise structures being constructed at a fast pace. Therefore, information of surface geology and surface sediment thickness for Jakarta city is urgently required in order to mitigate the effects of earthquake hazards in the future. Because of this need, we deployed 36 broadband and shortperiod stations across Jakarta to record seismic ambient noise. We apply cross-correlation method to the simultaneously recorded data to retrieve interstation Green's functions. We measure group velocity dispersion of the retrieved Green's functions by applying narrowband filters. Dispersion measurements are then inverted with a nonlinear tomographic technique to image the shallow structure of Jakarta and its surrounding regions. Preliminary results from tomographic maps show low velocities dominantly located in central, west and north Jakarta. While the highest rate obtained is between stations in South Jakarta. This conforms with the known geological conditions in which the structure of sedimentary cover in northern Jakarta is thicker than the southern part.

  10. Noise study on cone-beam CT FDK image reconstruction by improved area-simulating-volume technique

    Science.gov (United States)

    Liu, Yan; Wang, Jin; Zhang, Hao; Fan, Yi; Liang, Zhengrong

    2014-03-01

    Previous studies have reported that the volume-weighting technique has advantages over the linear interpolation technique for cone-beam computed tomography (CBCT) image reconstruction. However, directly calculating the intersecting volume between the pencil beam X-ray and the object is a challenge due to the computational complexity. Inspired by previous works in area-simulating volume (ASV) technique for 3D positron emission tomography, we proposed an improved ASV (IASV) technique, which can fast calculate the geometric probability of the intersection between the pencil beam and the object. In order to show the improvements of using IASV technique in volumeweighting based Feldkamp-Davis-Kress (VW-FDK) algorithm compared to the conventional linear interpolation technique based FDK algorithm (LI-FDK), the variances images from both theoretical prediction and empirical determination are described basing on the assumption of the uncorrelated and stationary noise for each detector bin. In digital phantom study, both of the theoretically predicted variance images and the empirically determined variance images concurred and demonstrated that the VW-FDK algorithm can result in uniformly distributed noise across the FOV. In the physical phantom study, the performance enhancements by the VW-FDK algorithm were quantitatively evaluated by the contrast-noise-ratio (CNR) merit. The CNR values from the VW-FDK result were about 40% higher than the conventional LI-FDK result. Therefore it can be concluded that the VW-FDK algorithm can efficiently address the non-uniformity noise and suppress noise level of the reconstructed images.

  11. GROUND DEFORMATION MONITORING IN QINGDAO COASTAL AREAS BY TIME-SERIES TERRASAR-X IMAGES

    OpenAIRE

    Hou, A. Y.; Qiao, X.; Li, D.

    2016-01-01

    As a new generation of high resolution and short revisit period of radar satellite, TerraSAR-X is not only able to meet the requirements of monitoring large scale surface subsidence, but also make it possible to monitor the small deformation of the short period. This articles takes the coastal areas of the west coast of Qingdao as the research object. With Small baselines subsets interferometry synthetic aperture radar (SBASI), this paper obtained the period the average annual rate of change ...

  12. Dense Point Cloud Extraction from UAV Captured Images in Forest Area

    OpenAIRE

    Tao, Wang; Lei, Yan; Mooney, Peter

    2011-01-01

    LIDAR (Light Detection And Ranging) is widely used in forestry applications to obtain information about tree density, composition, change, etc. An advantage of LIDAR is its ability to get this information in a 3D structure. However, the density of LIDAR data is low, the acquisition of LIDAR data is often very expensive, and it is difficult to be utilised in small areas. In this article we present an alternative to LIDAR by using a UAV (Unmanned Aerial Vehicle) to acquire ...

  13. Dynamic monitoring of Poyang Lake water body area using MODIS images between 2000 and 2014

    Science.gov (United States)

    Sun, Yayong; Huang, Shifeng; Li, Jiren; Li, Xiaotao; Ma, Jianwei; Li, Shanyang; Wang, Hui

    2015-12-01

    Poyang Lake, the largest freshwater lake of China, is well known for its ecological and economic importance as a dynamic wetland system. But, influenced by the climate change and human activity, Poyang Lake wetland has changed a lot. The long time series of Terra/MODIS data between 2000 and 2014 were utilized to investigate the variation of Poyang Lake and to analyze Poyang lake response to variation of local precipitation with the meteorological data. The results showed: (1) Poyang Lake water body area showed a significant seasonal variation, minimum value was about 690 km2 and maximum value reached 3500 km2, and inter-annual fluctuation; (2)For the past 15 year , local precipitation directly affected the inundation changes. In particular, the impact of rainfall during the first half of the year is more significant (the relation coefficient with R2 of 0.61); (3) Taking into account humid activities, the impoundment of the Three Gorges dam (TGD) had a certain impact on Poyang Lake water body area, especially the persistent reduction of Poyang lake surface area in November was deteriorated by the impounding of TGD in October after 2006. Finally, the study provides a theoretical basis and data for changes in Poyang Lake wetland research and protection.

  14. Deriving soil function maps to assess related ecosystem services using imaging spectroscopy in the Lyss agricultural area, Switzerland

    Science.gov (United States)

    Diek, Sanne; de Jong, Rogier; Braun, Daniela; Böhler, Jonas; Schaepman, Michael

    2014-05-01

    Soils play an important role in the benefits offered by ecosystems services. In densely populated Switzerland soils are a scarce resource, with high pressure on services ranging from urban expansion to over-utilization. Key change drivers include erosion, soil degradation, land management change and (chemical) pollution, which should be taken into consideration. Therefore there is an emerging need for an integrated, sustainable and efficient system assessing the management of soil and land as a resource. The use of remote sensing can offer spatio-temporal and quantitative information of extended areas. In particular imaging spectroscopy has shown to perfectly complement existing sampling schemes as secondary information for digital soil mapping. Although only the upper-most layer of soil interacts with light when using reflectance spectroscopy, it still can offer valuable information that can be utilized by farmers and decision makers. Fully processed airborne imaging spectrometer data from APEX as well as land cover classification for the agricultural area in Lyss were available. Based on several spectral analysis methods we derived multiple soil properties, including soil organic matter, soil texture, and mineralogy; complemented by vegetation parameters, including leaf area index, chlorophyll content, pigment distribution, and water content. The surface variables were retrieved using a combination of index-based and physically-based retrievals. Soil properties in partly to fully vegetated areas were interpolated using regression kriging based methods. This allowed the continuous assessment of potential soil functions as well as non-contiguous maps of abundances of combined soil and vegetation parameters. Based on a simple regression model we could make a rough estimate of ecosystem services. This provided the opportunity to look at the differences between the interpolated soil function maps and the non-contiguous (but combined) vegetation and soil function maps

  15. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the North Bamyan mineral district in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the North Bamyan mineral district, which has copper deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2006,2007, 2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such

  16. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Ahankashan mineral district in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Ahankashan mineral district, which has copper and gold deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2007,2008, 2009, 2010),but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this

  17. Seismic Imaging of the San Jacinto Fault Zone Area From Seismogenic Depth to the Surface

    Science.gov (United States)

    Ben-Zion, Y.

    2015-12-01

    I review multi-scale multi-signal seismological results on structural properties within and around the San Jacinto Fault Zone (SJFZ). The results are based on data of the regional southern California and ANZA networks, additional near-fault seismometers and linear arrays with instrument spacing 25-50 m that cross the SJFZ at several locations, and a spatially-dense rectangular array with 1108 vertical-component sensors separated by 10-30 m centered on the fault. The studies utilize earthquake data to derive Vp and Vs velocity models with horizontal resolution of 1-2 km over the depth section 2-15 km, ambient noise with frequencies up to 1 Hz to image with similar horizontal resolution the depth section 0.5-7 km, and high-frequency seismic noise from the linear and rectangular arrays for high-resolution imaging of the top 0.5 km. Pronounced damage regions with low seismic velocities and anomalous Vp/Vs ratios are observed around the SJFZ, as well as the San Andreas and Elsinore faults. The damage zones follow generally a flower-shape with depth. The section of the SJFZ from Cajon pass to the San Jacinto basin has a faster SW side, while the section farther to the SE has an opposite velocity contrast with faster NE side. The damage zones and velocity contrasts produce at various locations fault zone trapped and head waves that are utilized to obtain high-resolution information on inner fault zone components (bimaterial interfaces, trapping structures). Analyses of high-frequency noise recorded by the fault zone arrays reveal complex shallow material with very low seismic velocities and strong lateral and vertical variations.

  18. Compact Gamma-Ray Imager for In-Vivo Gene Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Greenwald, A. C.

    2000-06-01

    A compact, low-cost, gamma-ray imaging system is needed to study gene expression in small animals. State-of-the-art electronic imaging systems have insufficient resolution and animals must be sacrificed for detailed imaging that precludes time evolution studies. With improved electronics radioactive tracers attached to gene markers can be used to track the absorption and mobility of gene therapy medications in live animals. Other instrumentation being developed for medical applications does not have the response to match the radiation source for this work. The objective of this research was to develop thick film (Cd,Zn)Te detectors matched to the gamma ray energy of {sup 129}I. The detector would be a direct readout device using p-i-n diodes formed from the high Z material absorbing the radiation, with separate readout. Higher quality semiconducting material was expected from epitaxial growth on GaAs, a near lattice matched substrate. In practice, it was difficult to obtain material with high resistance and low leakage current. Spire Corporation achieved the goal of fabricating working detectors in (Cd,Zn)Te deposited on GaAs. The spectra of an alpha emitter ({sup 225}Am) was adequately resolved in thin film devices. Thick p-i-n diodes were fabricated but other processing problems prevented full demonstration of a gamma ray detector.

  19. Multibeam mapping of selected areas of the outer continental shelf, northwestern Gulf of Mexico; data, images, and GIS

    Science.gov (United States)

    Gardner, James V.; Beaudoin, Jonathan D.; Hughes-Clarke, John E.; Dartnell, Peter

    2002-01-01

    Following the publication of high-resolution (5-meter spatial resolution) multibeam echosounder (MBES) images of the Flower Garden Banks National Marine Sanctuary area of the northwestern Gulf of Mexico (Gardner et al., 1998), the Flower Garden Banks National Marine Sanctuary (FGBNMS) and the Minerals Management Service (MMS) have been interested in additional MBES data in the area. A coalition of FGBNMS, MMS, and the U.S. Geological Survey (USGS) was formed to map additional areas of interest in the northwestern Gulf of Mexico (fig. 1) in 2002. FGBNMS chose the survey areas, and the USGS chose the MBES. MMS and FGBNMS funded the mapping, and the USGS organized the ship and multibeam systems through a cooperative agreement between the USGS and the University of New Brunswick. The objective of the cruise was to map 12 regions of interest to MMS and the FGBNMS, including Alderdice, Sonnier, Geyer, Bright, Rankin (1 and 2), Jakkula, McNeil, Bouma, McGrail, Rezak, and Sidner Banks.

  20. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the South Bamyan mineral district in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the South Bamyan mineral district, which has areas with a spectral reflectance anomaly that require field investigation. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2006,2007, 2008),but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that

  1. Building Large Area CZT Imaging Detectors for a Wide-Field Hard X-ray Telescope - ProtoEXIST1

    CERN Document Server

    Hong, J; Grindlay, J; Chammas, N; Barthelemy, S; Baker, R; Gehrels, N; Nelson, K E; Labov, S; Collins, J; Cook, W R; McLean, R; Harrison, F

    2009-01-01

    We have constructed a moderately large area (32 cm2), fine pixel (2.5 mm pixel, 5 mm thick) CZT imaging detector which constitutes the first section of a detector module (256 cm2) developed for a balloon-borne wide-field hard X-ray telescope, ProtoEXIST1. ProtoEXIST1 is a prototype for the High Energy Telescope (HET) in the Energetic X-ray imaging Survey Telescope (EXIST), a next generation space-borne multi-wavelength telescope. We have constructed a large (nearly gapless) detector plane through a modularization scheme by tiling of a large number of 2 cm x 2 cm CZT crystals. Our innovative packaging method is ideal for many applications such as coded-aperture imaging, where a large, continuous detector plane is desirable for the optimal performance. Currently we have been able to achieve an energy resolution of 3.2 keV (FWHM) at 59.6 keV on average, which is exceptional considering the moderate pixel size and the number of detectors in simultaneous operation. We expect to complete two modules (512 cm2) withi...

  2. Detection of Low-Signal Pulvinar Areas Using Diffusion-Weighted Imaging in Patients with Dementia Experiencing Visual Hallucinations

    Science.gov (United States)

    Sugiura, Mayuko; Satoh, Masayuki; Tabei, Ken-ichi; Saito, Tomoki; Mori, Mutsuki; Abe, Makiko; Kida, Hirotaka; Maeda, Masayuki; Sakuma, Hajime; Tomimoto, Hidekazu

    2016-01-01

    Background Little research has been conducted regarding the role of pulvinar nuclei in the pathogenesis of visual hallucinations due to the difficulty of assessing abnormalities in this region using conventional magnetic resonance imaging (MRI). The present study aimed to retrospectively investigate the relative abilities of diffusion-weighted imaging (DWI), fluid-attenuated inversion recovery (FLAIR), and susceptibility-weighted imaging (SWI) to visualize the pulvinar and to ascertain the relationship between pulvinar visualization and visual hallucinations. Methods A retrospective analysis of 3T MRIs from 73 patients (31 males, 42 females; mean age 73.5 ± 12.7 years) of the Memory Clinic of Mie University Hospital was conducted. Correlations between pulvinar visualization and the following were analyzed: age, sex, education, hypertension, hyperlipidemia, diabetes mellitus, Mini-Mental State Examination score, Evans index, and visual hallucinations. Results DWI detected low-signal pulvinar areas in approximately half of the patients (52.1%). Participants with pulvinar visualization were significantly older, and the pulvinar was more frequently visualized in patients who had experienced visual hallucinations compared to those who had not. No significant association was observed between whole brain atrophy and pulvinar visualization. Conclusions The results of the present study indicate that diffusion-weighted 3T MRI is the most suitable method for the detection of pulvinar nuclei in patients with dementia experiencing visual hallucinations.

  3. Temporal and spatial characteristics of the area at risk investigated using computed tomography and T1-weighted magnetic resonance imaging

    DEFF Research Database (Denmark)

    van der Pals, Jesper; Hammer-Hansen, Sophia; Nielles-Vallespin, Sonia;

    2015-01-01

    the AAR. We investigated the presence of a lateral perfusion gradient within the AAR and validated CMR measures of AAR against three independent reference standards of high quality. METHODS AND RESULTS: Computed tomography (CT) perfusion imaging, microsphere blood flow analysis, T1-weighted 3T CMR...... ventricular mass (LVM) vs. CT; -1.49 ± 4.04% LVM vs. blood flow and -1.01 ± 4.18% LVM vs. pathology]. The lateral portion of the AAR had higher perfusion than the core of the AAR by CT perfusion imaging (40.7 ± 11.8 vs. 25.2 ± 17.7 Hounsfield units, P = 0.0008) and microsphere blood flow (0.11 ± 0.04 vs. 0......AIMS: Cardiovascular magnetic resonance (CMR) imaging can measure the myocardial area at risk (AAR), but the technique has received criticism for inadequate validation. CMR commonly depicts an AAR that is wider than the infarct, which in turn would require a lateral perfusion gradient within...

  4. A radiopharmaceutical for imaging areas of lymphocytic infiltration: [sup 123]I-interleukin-2. Labelling procedure and animal studies

    Energy Technology Data Exchange (ETDEWEB)

    Signore, A.; Chianelli, M.; Toscano, A.; Monetini, L.; Ronga, G.; Pozzilli, P.; Negri, M. (Policlinico Umberto, Rome (Italy). Clinica Medica 2); Nimmon, C.C.; Britton, K.E. (Saint Bartholomew' s Hospital, London (United Kingdom). Dept. of Nuclear Medicine)

    1992-10-01

    The labelling of interleukin-2 (IL-2) with [sup 123]I and its in vivo application for imaging chronic pathological lymphocytic infiltrations are described. The lactoperoxidase/glucoseoxidase technique was the labelling method of choice leading to immunoreactive IL-2 with high specific activity. Labelled IL-2 was injected in diabetes-prone non-obese diabetic (NOD) mice with pancreatic lymphocytic infiltration. As control animals, Balb/c mice were used. As specificity control, monoclonal antibodies AMT13 and UCHT1, bovine serum albumin and [alpha]-lactalbumin were radioiodinated and injected in mice. Eighteen NOD mice and four control Balb/c mice were used for gamma camera imaging experiments. Fifty-four NOD and 20 Balb/c mice were used for time course single organ counting and autoradiography. Gamma camera images showed that radioactivity accumulated in the pancreatic region from the 10th minute onwards in NOD mice injected with [sup 123]I-IL-2 but not in Balb/c mice, or in NOD mice injected with control radiopharmaceuticals. These findings were confirmed by counting the radioactivity present in single organs. Autoradiography of NOD pancreas, after injection of labelled IL-2, showed that radioactivity was specifically associated with infiltrating lymphocytes. In conclusion, this technique is highly specific and easy to perform and we suggest its application in humans for in vivo detection of areas of lymphocytic infiltration. (Author).

  5. Hot embossing holographic images in BOPP shrink films through large-area roll-to-roll nanoimprint lithography

    Science.gov (United States)

    Jiang, Menglin; Lin, Shiwei; Jiang, Wenkai; Pan, Nengqian

    2014-08-01

    Diffraction grating-based holographic images have been successfully replicated in biaxially oriented polypropylene (BOPP) shrink films through large-area roll-to-roll nanoimprint technique. Such hot embossing of holographic images on BOPP films represents a promising means of creating novel security features in packaging applications. The major limitation of the high-quality replication is the relatively large thermal shrinkage of BOPP shrink film. However, although an appropriate shrinkage is demanded after embossing, over-shrinking not only causes distortion in embossed images, but also reduces the various properties of BOPP shrink films mainly due to the disappearance of orientation. The effects of embossing temperature on the mechanical, thermal and optical properties as well as polymer surface morphologies were systematically analyzed. The results show that the optimal process parameters are listed as follows: the embossing temperature at 104-110 °C, embossing force 6 kg/cm2 and film speed 32 m/min. The variation in flow behavior of polymer surface during hot embossing process is highly dependent on the temperature. In addition, the adhesion from the direct contact between the rubber press roller and polymer surfaces is suggested to cause the serious optical properties failure.

  6. SU-E-I-27: Estimating KERMA Area Product for CT Localizer Images

    International Nuclear Information System (INIS)

    Purpose: To estimate the free-in-air KERMA-Area Product (KAP) incident on patients due to CT localizer scans for common CT exams. Methods: In-plane beam intensity profiles were measured in localizer acquisition mode using OSLs for a 64 slice MDCT scanner (Lightspeed VCT, GE Medical Systems, Waukesha WI). The z-axis beam width was measured as a function of distance from isocenter. The beam profile and width were used to calculate a weighted average air KERMA per unit mAs as a function of intercepted x-axis beam width for objects symmetric about the localizer centerline.Patient areas were measured using manually drawn regions and divided by localizer length to determine average width. Data were collected for 50 head exams (lateral localizer only), 15 head/neck exams, 50 chest exams, and 50 abdomen/pelvis exams. Mean patient widths and acquisition techniques were used to calculate the weighted average free-in-air KERMA, which was multiplied by the patient area to estimate KAP. Results: Scan technique was 120 kV tube voltage, 10 mA current, and table speed of 10 cm/s. The mean ± standard deviation values of KAP were 120 ± 11.6, 469 ± 62.6, 518 ± 45, and 763 ± 93 mGycm2 for head, head/neck, chest, and abdomen/pelvis exams, respectively. For studies with AP and lateral localizers, the AP/lateral area ratio was 1.20, 1.33, and 1.24 for the head/neck, chest, and abdomen/pelvis exams, respectively. However, the AP/lateral KAP ratios were 1.12, 1.08, and 1.07, respectively. Conclusion: Calculation of KAP in CT localizers is complicated by the non-uniform intensity profile and z-axis beam width. KAP values are similar to those for simple radiographic exams such as a chest radiograph and represent a small fraction of the x-ray exposure at CT. However, as CT doses are reduced the localizer contribution will be a more significant fraction of the total exposure

  7. Handheld and mobile hyperspectral imaging sensors for wide-area standoff detection of explosives and chemical warfare agents

    Science.gov (United States)

    Gomer, Nathaniel R.; Gardner, Charles W.; Nelson, Matthew P.

    2016-05-01

    Hyperspectral imaging (HSI) is a valuable tool for the investigation and analysis of targets in complex background with a high degree of autonomy. HSI is beneficial for the detection of threat materials on environmental surfaces, where the concentration of the target of interest is often very low and is typically found within complex scenery. Two HSI techniques that have proven to be valuable are Raman and shortwave infrared (SWIR) HSI. Unfortunately, current generation HSI systems have numerous size, weight, and power (SWaP) limitations that make their potential integration onto a handheld or field portable platform difficult. The systems that are field-portable do so by sacrificing system performance, typically by providing an inefficient area search rate, requiring close proximity to the target for screening, and/or eliminating the potential to conduct real-time measurements. To address these shortcomings, ChemImage Sensor Systems (CISS) is developing a variety of wide-field hyperspectral imaging systems. Raman HSI sensors are being developed to overcome two obstacles present in standard Raman detection systems: slow area search rate (due to small laser spot sizes) and lack of eye-safety. SWIR HSI sensors have been integrated into mobile, robot based platforms and handheld variants for the detection of explosives and chemical warfare agents (CWAs). In addition, the fusion of these two technologies into a single system has shown the feasibility of using both techniques concurrently to provide higher probability of detection and lower false alarm rates. This paper will provide background on Raman and SWIR HSI, discuss the applications for these techniques, and provide an overview of novel CISS HSI sensors focused on sensor design and detection results.

  8. Acidic Barren Slope Profiling using Electrical Resistivity Imaging (ERI) at Ayer Hitam area Johor, Malaysia

    Science.gov (United States)

    Azhar, A. T. S.; Hazreek, Z. A. M.; Aziman, M.; Haimi, D. S.; Hafiz, Z. M.

    2016-04-01

    Recently, non-destructive method such as the electrical resistivity technique has become increasingly popular in engineering, environmental, mining and archeological studies nowadays. This method was popular in subsurface profiling due to its ability to replicate the images of the subsurface indirectly. The soil slope found in Batu Pahat, specifically in Ayer Hitam, is known to be problematic due to its barren condition. This location is believed to contain futile soil due to its difficulty in supporting the growth of vegetations. In the past, acidic barren slope assessment using non-destructive method was rarely being used due to several reasons related to the equipment and knowledge constraints. Hence, this study performed an electrical resistivity imaging using ABEM Terrameter LS in order to investigate the acidic barren slope conditions. Field data acquisition was based on Schlumberger and Wenner arrays while RES2DINV software was used to analyze and generate a 2-D model of the problematic subsurface profile. Based on electrical resistivity results, it was found that the acidic barren slope studied consists of two main zones representing residual soil (electrical resistivity value = 10 - 600 Ωm) and shale (electrical resistivity value = 20 - 2000 Ωm). The results of resistivity value were correlated with the physical mapping and the in situ mackintosh probe test for verification purposes. It was found that the maximum depth of the mackintosh probe test was 1.8 m due to its ground penetration limitation. However, the results of the resistivity section managed to achieve greater depth up to 40 m. Hence, the correlation between electrical resistivity and mackintosh probe results can only be performed at certain depth of the acidic barren slope profile in contrast with the physical mapping which able to define the whole section of the barren soil slope structure. Finally, a good match of electrical resistivity results calibrated with mackintosh and physical

  9. A Novel Passive Millimeter Imager for Broad-Area Search - Final Report on Project PL09-NPMI-PD07 (PNNL-55180)

    Energy Technology Data Exchange (ETDEWEB)

    Tedeschi, Jonathan R.; Bernacki, Bruce E.; Kelly, James F.; Sheen, David M.; Harris, Robert V.; Hall, Thomas E.; Hatchell, Brian K.; Knopik, Clint D.; Lechelt, Wayne M.; McMakin, Douglas L.; Mendoza, Albert; Severtsen, Ronald H.; Valdez, Patrick LJ

    2011-12-31

    This report describes research and development efforts toward a novel passive millimeter-wave (mm-wave) electromagnetic imaging device for broad-area search. It addresses the technical challenge of detecting anomalies that occupy a small fraction of a pixel. The purpose of the imager is to pinpoint suspicious locations for cuing subsequent higher-resolution imaging. The technical basis for the approach is to exploit thermal and polarization anomalies that distinguish man-made features from natural features.

  10. Quantitative Imaging of D-2-Hydroxyglutarate in Selected Histological Tissue Areas by a Novel Bioluminescence Technique.

    Science.gov (United States)

    Voelxen, Nadine F; Walenta, Stefan; Proescholdt, Martin; Dettmer, Katja; Pusch, Stefan; Mueller-Klieser, Wolfgang

    2016-01-01

    Patients with malignant gliomas have a poor prognosis with average survival of less than 1 year. Whereas in other tumor entities the characteristics of tumor metabolism are successfully used for therapeutic approaches, such developments are very rare in brain tumors, notably in gliomas. One metabolic feature characteristic of gliomas, in particular diffuse astrocytomas and oligodendroglial tumors, is the variable content of D-2-hydroxyglutarate (D2HG), a metabolite that was discovered first in this tumor entity. D2HG is generated in large amounts due to various "gain-of-function" mutations in the isocitrate dehydrogenases IDH1 and IDH2. Meanwhile, D2HG has been detected in several other tumor entities, including intrahepatic bile-duct cancer, chondrosarcoma, acute myeloid leukemia, and angioimmunoblastic T-cell lymphoma. D2HG is barely detectable in healthy tissue (bioluminescence assay for determining D2HG in sections of snap-frozen tissue. The assay was verified independently by photometric tests and liquid chromatography/mass spectrometry. The novel technique allows the microscopically resolved determination of D2HG in a concentration range of 0-10 μmol/g tissue (wet weight). In combination with the already established bioluminescence imaging techniques for ATP, glucose, pyruvate, and lactate, the novel D2HG assay enables a comparative characterization of the metabolic profile of individual tumors in a further dimension.

  11. Integration of optical and synthetic aperture radar (SAR) images to differentiate grassland and alfalfa in Prairie area

    Science.gov (United States)

    Hong, Gang; Zhang, Aining; Zhou, Fuqun; Brisco, Brian

    2014-05-01

    Alfalfa presents a huge potential biofuel source in the Prairie Provinces of Canada. However, it remains a challenge to find an ideal single satellite sensor to monitor the regional spatial distribution of alfalfa on an annual basis. The primary interest of this study is to identify alfalfa spatial distribution through effectively differentiating alfalfa from grasslands, given their spectral similarity and same growth calendars. MODIS and RADARSAT-2 ScanSAR narrow mode were selected for regional-level grassland and alfalfa differentiation in the Prairie Provinces, due to the high frequency revisit of MODIS, the weather independence of ScanSAR as well as the large area coverage and the complementary characteristics SAR and optical images. Combining MODIS and ScanSAR in differentiating alfalfa and grassland is very challenging, since there is a large spatial resolution difference between MODIS (250 m) and ScanSAR narrow (50 m). This study investigated an innovative image fusion technique for combining MODIS and ScanSAR and obtaining a synthetic image which has the high spatial details derived from ScanSAR and the colour information from MODIS. The field trip was arranged to collect ground truth to label and validate the classification results. The fusion classification result shows significant accuracy improvement when compared with either ScanSAR or MODIS alone or with other commonly-used data combination methods, such as multiple files composites. This study has shown that the image fusion technique used in this study can combine the structural information from high resolution ScanSAR and colour information from MODIS to significantly improve the classification accuracy between alfalfa and grassland.

  12. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Nuristan mineral district in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.; Arko, Scott A.; Harbin, Michelle L.; Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Nuristan mineral district, which has gem, lithium, and cesium deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2008,2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS

  13. A preliminary evaluation of ERTS-1 images on the volcanic areas of Southern Italy

    Science.gov (United States)

    Cassinis, R.; Lechi, G. M.

    1973-01-01

    The test site selected for the investigation covers nearly all the regions of active and quiescent volcanism in southern Italy, i.e. the eastern part of the island of Sicily, the Aeolian Islands and the area of Naples. The three active European volcanoes (Etna, Stromboli and Vesuvius) are included. The investigation is in the frame of a program for the surveillance of active volcanoes by geophysical (including remote sensing thermal methods) and geochemical methods. By the multispectral analysis of ERTS-1 data it is intended to study the spectral behavior of the volcanic materials as well as the major geological lineaments with special reference to those associated with the volcanic region. Secondary objectives are also the determination of the hydrographic network seasonal behavior and the relationship between the vegetation cover and the different type of soils and rocks.

  14. The Campi Flegrei Blind Test: Evaluating the Imaging Capability of Local Earthquake Tomography in a Volcanic Area

    Directory of Open Access Journals (Sweden)

    E. Priolo

    2012-01-01

    Full Text Available During the 1982–1984 bradyseismic crises in the Campi Flegrei area (Italy, the University of Wisconsin deployed a network of seismological stations to record local earthquakes. In order to analyse the potential of the recorded data in terms of tomographic imaging, a blind test was recently set up and carried out in the framework of a research project. A model representing a hypothetical 3D structure of the area containing the Campi Flegrei caldera was also set up, and a synthetic dataset of time arrivals was in turn computed. The synthetic dataset consists of several thousand P- and S-time arrivals, computed at about fourteen stations. The tomographic inversion was performed by four independent teams using different methods. The teams had no knowledge of either the input velocity model or the earthquake hypocenters used to create the synthetic dataset. The results obtained by the different groups were compared and analysed in light of the true model. This work provides a thorough analysis of the earthquake tomography potential of the dataset recording the seismic activity at Campi Flegrei in the 1982–1984 period. It shows that all the tested earthquake tomography methods provide reliable low-resolution images of the background velocity field of the Campi Flegrei area, but with some differences. However, none of them succeeds in detecting the hypothetical structure details (i.e. with a size smaller than about 1.5–2 km, such as a magmatic chamber 4 km deep and especially the smaller, isolated bodies, which represent possible magmatic chimneys and intrusions.

  15. Synaesthetic colour in the brain: beyond colour areas. A functional magnetic resonance imaging study of synaesthetes and matched controls.

    Directory of Open Access Journals (Sweden)

    Tessa M van Leeuwen

    Full Text Available BACKGROUND: In synaesthesia, sensations in a particular modality cause additional experiences in a second, unstimulated modality (e.g., letters elicit colour. Understanding how synaesthesia is mediated in the brain can help to understand normal processes of perceptual awareness and multisensory integration. In several neuroimaging studies, enhanced brain activity for grapheme-colour synaesthesia has been found in ventral-occipital areas that are also involved in real colour processing. Our question was whether the neural correlates of synaesthetically induced colour and real colour experience are truly shared. METHODOLOGY/PRINCIPAL FINDINGS: First, in a free viewing functional magnetic resonance imaging (fMRI experiment, we located main effects of synaesthesia in left superior parietal lobule and in colour related areas. In the left superior parietal lobe, individual differences between synaesthetes (projector-associator distinction also influenced brain activity, confirming the importance of the left superior parietal lobe for synaesthesia. Next, we applied a repetition suppression paradigm in fMRI, in which a decrease in the BOLD (blood-oxygenated-level-dependent response is generally observed for repeated stimuli. We hypothesized that synaesthetically induced colours would lead to a reduction in BOLD response for subsequently presented real colours, if the neural correlates were overlapping. We did find BOLD suppression effects induced by synaesthesia, but not within the colour areas. CONCLUSIONS/SIGNIFICANCE: Because synaesthetically induced colours were not able to suppress BOLD effects for real colour, we conclude that the neural correlates of synaesthetic colour experience and real colour experience are not fully shared. We propose that synaesthetic colour experiences are mediated by higher-order visual pathways that lie beyond the scope of classical, ventral-occipital visual areas. Feedback from these areas, in which the left parietal

  16. Preoperative blood oxygen level-dependent functional magnetic resonance imaging in patients with gliomas involving the motor cortical areas

    Institute of Scientific and Technical Information of China (English)

    XIE Jian; CHEN Xu-zhu; JIANG Tao; LI Shou-wei; LI Zi-xiao; ZHANG Zhong; DAI Jian-ping; WANG Zhong-cheng

    2008-01-01

    Background Blood oxygen level-dependent(BOLD)functional magnetic resonance imaging(fMRI)plays an important role in identifying functional cortical areas of the brain.especially In patients with gliomas.This study aimed to assess the value of fMRI in presurgical planning and functional outcome of patients with gliomas in the motor cortical areas.Methods Twenty-six patients with gliomas in the motor cortex were recruited in the study.Before operation.fMRI was performed in each patient to obtain the mapping of bilateral hands area on the primary sensorimotor cortex.This examination was performed on a 3.0T scanner with a bilateral hands movement paradigm.During microsurgery under awake anesthesia,the motor area was identified using direct electrical stimulation and compared with preoperative mapping.Finally the tumor was resected as much as possible with the motor cortex preserved in each patlent.Karnofsky performance status(KPS)was evaluated in all patients before and after operation.Results Twenty-three patients showed a successful fMRI mapping.Among them,19 were calssified to be grade Ⅲ;4,grade Ⅱ;3,grade Ⅰ.The operation time was about 7 hours in the 23 patients,8.5 hours in the other 3.The pre- and pOstODerative KPS score was 82.3±8.6 and 94.2±8.1,respectively.Conclusions Preoperative fMRI of the hand motor area shows a high consistency with intraoperative cortical electronic stimulation.Combined use of the two methods shows a maximum benefit in surgical treatment.

  17. Quantitative Image Analysis of Epithelial and Stromal Area in Histological Sections of Colorectal Cancer: An Emerging Diagnostic Tool

    Directory of Open Access Journals (Sweden)

    R. Rogojanu

    2015-01-01

    Full Text Available In colorectal cancer (CRC, an increase in the stromal (S area with the reduction of the epithelial (E parts has been suggested as an indication of tumor progression. Therefore, an automated image method capable of discriminating E and S areas would allow an improved diagnosis. Immunofluorescence staining was performed on paraffin-embedded sections from colorectal tumors (16 samples from patients with liver metastasis and 18 without. Noncancerous tumor adjacent mucosa (n=5 and normal mucosa (n=4 were taken as controls. Epithelial cells were identified by an anti-keratin 8 (K8 antibody. Large tissue areas (5–63 mm2/slide including tumor center, tumor front, and adjacent mucosa were scanned using an automated microscopy system (TissueFAXS. With our newly developed algorithms, we showed that there is more K8-immunoreactive E in the tumor center than in tumor adjacent and normal mucosa. Comparing patients with and without metastasis, the E/S ratio decreased by 20% in the tumor center and by 40% at tumor front in metastatic samples. The reduction of E might be due to a more aggressive phenotype in metastasis patients. The novel software allowed a detailed morphometric analysis of cancer tissue compartments as tools for objective quantitative measurements, reduced analysis time, and increased reproducibility of the data.

  18. Impact of intraoperative magnetic resonance imaging and functional neuronavigation on surgical outcome in patients with gliomas involving language areas.

    Science.gov (United States)

    Zhang, Jiashu; Chen, Xiaolei; Zhao, Yan; Wang, Fei; Li, Fangye; Xu, Bainan

    2015-04-01

    Balancing the benefit of extensive tumor resection with the consequence of potential postoperative language deficits remains a challenge in glioma surgery involving language areas. This study is designed to evaluate the impact of intraoperative magnetic resonance imaging (iMRI) and functional neuronavigation on surgical outcome in patients with gliomas involving language areas. Two hundred seventeen patients were prospectively enrolled, 124 in the study group underwent iMRI and functional neuronavigation-guided microsurgery and 93 in the control group underwent conventional navigation-guided microsurgery. Extent of tumor volume resection (EoR) and rate of gross total resection (rGTR) were calculated perioperatively. Aphasia quotient (AQ) was assessed to evaluate the change of language function perioperatively and at 6-month follow-up. Survival outcome for glioblastoma, including progression-free survival (PFS) and overall survival (OS), were recorded. In 198 glioma patients (112 in the study group and 86 in the control group), EoR (95.50 versus 89.85%, p language functions were also better at 6-month follow-up in the study group (87.47 versus 78.73, p = 0.001). Furthermore, postoperative new aphasia occurred in 34.8% of the control group, whereas it occurred only in 2.3% of the study group (p functional neuronavigation may help maximize tumor resection, minimize language deficits in patients with gliomas involving language areas, and improve survival time for patients with glioblastomas.

  19. THE STUDY ON HEIGHT INFORMATION EXTRACTION OF CULTURAL FEATURES IN REMOTE SENSING IMAGES BASED ON SHADOW AREAS

    Directory of Open Access Journals (Sweden)

    Z. Bao-Ming

    2012-09-01

    Full Text Available Cultural feature is important element in geospatial information library and the height information is important information of cultural features. The existences of the height information and its precision have direct influence over topographic map, especially the quality of large-scale and medium-scale topographic map, and the level of surveying and mapping support. There are a lot of methods about height information extraction, in which the main methods are ground survey (field direct measurement spatial sensor and photogrammetric ways. However, automatic extraction is very tough. This paper has had an emphasis on segmentation algorithm on shadow areas under multiple constraints and realized automatic extraction of height information by using shadow. Binarization image can be obtained using gray threshold estimated under the multiple constraints. On the interesting area, spot elimination and region splitting are made. After region labeling and non-shadowed regions elimination, shadow area of cultural features can be found. Then height of the cultural features can be calculated using shadow length, sun altitude angle, azimuth angle, and sensor altitude angle, azimuth angle. A great many of experiments have shown that mean square error of the height information of cultural features extraction is close to 2 meter and automatic extraction rate is close to 70%.

  20. Validation of Vehicle Candidate Areas in Aerial Images Using Color Co-Occurrence Histograms

    Science.gov (United States)

    Leister, W.; Tuermer, S.; Reinartz, P.; Hoffmann, K. H.; Stilla, U.

    2013-10-01

    Traffic monitoring plays an important role in transportation management. In addition, airborne acquisition enables a flexible and realtime mapping for special traffic situations e.g. mass events and disasters. Also the automatic extraction of vehicles from aerial imagery is a common application. However, many approaches focus on the target object only. As an extension to previously developed car detection techniques, a validation scheme is presented. The focus is on exploiting the background of the vehicle candidates as well as their color properties in the HSV color space. Therefore, texture of the vehicle background is described by color co-occurrence histograms. From all resulting histograms a likelihood function is calculated giving a quantity value to indicate whether the vehicle candidate is correctly classified. Only a few robust parameters have to be determined. Finally, the strategy is tested with a dataset of dense urban areas from the inner city of Munich, Germany. First results show that certain regions which are often responsible for false positive detections, such as vegetation or road markings, can be excluded successfully.

  1. Assessment of Rosia Jiu Mining Area Through TerraSAR-X New Imaging Modes

    Science.gov (United States)

    Poenaru, V.; Popescu, A.; Patrascu, C.; Cuculici, Roxana

    2015-05-01

    The paper evaluates new Staring Spotlight mode capabilities to monitor the mining activities impacts on the environment to ensure an effective management and to prevent possible natural and technological hazards. The societal and environmental impacts are huge such as: the topographic alteration, changes in the soil structure and vegetation coverage, influence on the underground water resources and on the rain water draining regime and air pollution. Rosia Jiu opencast test site is affected by subsidence phenomena caused by the closing of the hollows remained from the underground exploitation of lignite and by altering of the hidro-geological conditions, due to the applying of a forced and high intensity dewatering of the aquifer system within the area. A methodology based on deformation maps is designed for monitoring of the elastic deformation, early warning stage and detection of the risk occurrence. Intense mining activities from the summer - autumn seasons implied as interferometric pairs to have very low coherence making almost impossible to find PS candidates.

  2. Fabrication of large area X-ray diffraction grating for X-ray phase imaging

    International Nuclear Information System (INIS)

    X-ray lithography, which uses highly directional synchrotron radiation, is one of the technologies that can be used for fabricating micrometer-sized structures. In X-ray lithography, the accuracy of the fabricated structure depends largely on the accuracy of the X-ray mask. Since X-ray radiation is highly directional, a micro-fabrication technology that produces un-tapered and high aspect ratio highly absorbent structures on a low absorbent membrane is required. Conventionally, a resin material is used as the support membrane for large area X-ray masks. However, resin membranes have the disadvantage that they can sag after several cycles of X-ray exposure due to the heat generated by the X-rays. Therefore, we proposed and used thin carbon wafers for the membrane material because carbon has an extremely small thermal expansion coefficient. We fabricated new carbon membrane X-ray masks, and these results of X-ray lithography demonstrate the superior performance.

  3. Comparative analysis of different retrieval methods for mapping grassland leaf area index using airborne imaging spectroscopy

    Science.gov (United States)

    Atzberger, Clement; Darvishzadeh, Roshanak; Immitzer, Markus; Schlerf, Martin; Skidmore, Andrew; le Maire, Guerric

    2015-12-01

    Fine scale maps of vegetation biophysical variables are useful status indicators for monitoring and managing national parks and endangered habitats. Here, we assess in a comparative way four different retrieval methods for estimating leaf area index (LAI) in grassland: two radiative transfer model (RTM) inversion methods (one based on look-up-tables (LUT) and one based on predictive equations) and two statistical modelling methods (one partly, the other entirely based on in situ data). For prediction, spectral data were used that had been acquired over Majella National Park in Italy by the airborne hyperspectral HyMap instrument. To assess the performance of the four investigated models, the normalized root mean squared error (nRMSE) and coefficient of determination (R2) between estimates and in situ LAI measurements are reported (n = 41). Using a jackknife approach, we also quantified the accuracy and robustness of empirical models as a function of the size of the available calibration data set. The results of the study demonstrate that the LUT-based RTM inversion yields higher accuracies for LAI estimation (R2 = 0.91, nRMSE = 0.18) as compared to RTM inversions based on predictive equations (R2 = 0.79, nRMSE = 0.38). The two statistical methods yield accuracies similar to the LUT method. However, as expected, the accuracy and robustness of the statistical models decrease when the size of the calibration database is reduced to fewer samples. The results of this study are of interest for the remote sensing community developing improved inversion schemes for spaceborne hyperspectral sensors applicable to different vegetation types. The examples provided in this paper may also serve as illustrations for the drawbacks and advantages of physical and empirical models.

  4. Exploration and monitoring geothermal activity using Landsat ETM + images. A case study at Aso volcanic area in Japan

    Science.gov (United States)

    Mia, Md. Bodruddoza; Nishijima, Jun; Fujimitsu, Yasuhiro

    2014-04-01

    Thermal activity monitoring in and around active volcanic areas using remote sensing is an essential part of volcanology nowadays. Three identical approaches were used for thermal activity exploration at Aso volcanic area in Japan using Landsat ETM + images. First, the conventional methods for hydrothermal alteration mapping were applied to find the most active thermal region after exploring geothermal indicator minerals. Second, we found some thermally highly anomalous regions around Nakadake crater using land surface temperature estimation. Then, the Stefan-Boltzmann equation was used for estimating and also monitoring radiative heat flux (RHF) from the most active region of about 8 km2 in and around Nakadake crater in the central part of the Aso volcano. To fulfill the required parameter in the Stefan-Boltzmann equation for radiative heat flux, the NDVI (Normalized differential vegetation index) method was used for spectral emissivity, and the mono-window algorithm was used for land surface temperature of this study area. The NDVI value was used to divide land-cover in the study area into four types: water, bare ground, mixed and vegetated land. The bare land was found within the most active region. Vegetation coverage area showed an inverse relationship with total RHF in this study as health of thermally stressed vegetation supports this relationship. The spatial distribution of spectral emissivity ranged from 0.94 to 0.99 in our study. Land surface temperature was estimated using a mono-window algorithm and was highest LST in 2008 and lowest in 2011. The results of RHF showed that the highest pixel RHF was found to be about 296 W/m2 in 2008. Total RHF was obtained of about 607 MW in 2002 and the lowest was about 354 MW in 2008. The RHF anomaly area was found the highest in 2002 and was lowest in 2011. The highest total heat discharge rate (HDR) obtained about 3918 MW in 2002 and lowest total HDR about 2289 MW in 2008 from this study area. But in the case of

  5. Myocardial area at risk after ST-elevation myocardial infarction measured with the late gadolinium enhancement after scar remodeling and T2-weighted cardiac magnetic resonance imaging

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Engstrøm, Thomas; Mathiasen, Anders B;

    2011-01-01

    To evaluate the myocardial area at risk (AAR) measured by the endocardial surface area (ESA) method on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) when applied after scar remodeling (3 months after index infarction) compared to T2-weighted CMR imaging. One hundred...

  6. Myocardial area at risk after ST-elevation myocardial infarction measured with the late gadolinium enhancement after scar remodeling and T2-weighted cardiac magnetic resonance imaging

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Engstrøm, Thomas; Mathiasen, Anders B;

    2012-01-01

    To evaluate the myocardial area at risk (AAR) measured by the endocardial surface area (ESA) method on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) when applied after scar remodeling (3 months after index infarction) compared to T2-weighted CMR imaging. One hundred...

  7. Magnetic resonance diffusion tensor imaging with fluorescein sodium dyeing for surgery of gliomas in brain motor functional areas

    Institute of Scientific and Technical Information of China (English)

    LIU Jia-gang; YANG Shuai-feng; LIU Yan-hui; WANG Xiang; MAO Qing

    2013-01-01

    Background Tumor surgery in brain motor functional areas remains challenging.Novel techniques are being developed to gain maximal and safe resection for brain tumor surgery.Herein,we assessed the magnetic resonance diffusion tensor imaging (MR-DTI) and fluorescein sodium dyeing (FLS) guiding technique for surgery of glioma located in brain motor functional areas.Methods Totally 83 patients were enrolled according to our inclusion and exclusion criteria (56 patients in experimental group,27 patients in control group).In the experimental group,the surgical approach was designed by DTI imaging,which showed the relationship between the tumor and motor tract.The range of resection in the operation was determined using the FLS-stained area,which recognized the tumor and its infiltrated tissue.The traditional routine method was used in the control group.Postoperatively,all patients underwent enhanced brain MRI within 72 hours to ascertain the extent of resection.Patients were followed in our outpatient clinic over 6-24 months.Neurological deficits and Karnofsky scoring (KPS) were evaluated.Results There were no significant differences in balance test indexes of preoperative data (sex,age,lesion location and volume,and neurological deficits before operation) and diagnosis of histopathology between the two groups.There was a trend in the experimental group for greater rates of gross total resection (80.4% vs.40.7%),and the paralysis rate caused by surgery was lower in experimental (25.0%) vs.control (66.7%) groups (P <0.05).The 6-month KPS in the low-grade and high-grade gliomas was 91±11 and 73±26,respectively,in the experimental group vs.82±9 and 43±27,respectively,in the control group (P <0.05 for both).Conclusions MR-DTI and FLS dye guiding for surgery of glioma located in brain motor functional areas can increase the gross total resection rate,decrease the paralysis rate caused by surgery,and improve patient quality of life compared with traditional

  8. Raman imaging in geomicrobiology: endolithic phototrophic microorganisms in gypsum from the extreme sun irradiation area in the Atacama Desert.

    Science.gov (United States)

    Vítek, Petr; Ascaso, Carmen; Artieda, Octavio; Wierzchos, Jacek

    2016-06-01

    The Raman imaging method was successfully applied for mapping the distribution of biomolecules (e.g., pigments) associated with cryptoendolithic and hypoendolithic microorganisms, as well as the inorganic host mineral matrix that forms the habitat for the biota. To the best of our knowledge, this is the first comprehensive study in the field of geomicrobiology based on this technique. The studied microbial ecosystem was located nearly 3000 m above sea level within the driest desert on Earth, the Atacama in Chile. Enhancement of carotenoid Raman signal intensity close to the surface was registered at different areas of endolithic colonization dominated by algae, with cyanobacteria present as well. This is interpreted as an adaptation mechanism to the excessive solar irradiation. On the other hand, cyanobacteria synthesize scytonemin as a passive UV-screening pigment (found at both the hypoendolithic and cryptoendolithic positions). The distribution of the scytonemin Raman signal was mapped simultaneously with the surrounding mineral matrix. Thus, mapping was done of the phototrophic microorganisms in their original microhabitat together with the host rock environment. Important information which was resolved from the Raman imaging dataset of the host rock is about the hydration state of Ca-sulfate, demonstrated on the presence of gypsum (CaSO4·2H2O) and the absence of both anhydrite (CaSO4) and bassanite (CaSO4·1/2H2O). Obtaining combined "in situ" simultaneous information from the geological matrix (inorganic) together with the microbial biomolecules (organic) is discussed and concluded as an important advantage of this technique. We discuss how selection of the laser wavelength (785 and 514.5-nm) influences the Raman imaging results. PMID:27055886

  9. Aerial Images from AN Uav System: 3d Modeling and Tree Species Classification in a Park Area

    Science.gov (United States)

    Gini, R.; Passoni, D.; Pinto, L.; Sona, G.

    2012-07-01

    The use of aerial imagery acquired by Unmanned Aerial Vehicles (UAVs) is scheduled within the FoGLIE project (Fruition of Goods Landscape in Interactive Environment): it starts from the need to enhance the natural, artistic and cultural heritage, to produce a better usability of it by employing audiovisual movable systems of 3D reconstruction and to improve monitoring procedures, by using new media for integrating the fruition phase with the preservation ones. The pilot project focus on a test area, Parco Adda Nord, which encloses various goods' types (small buildings, agricultural fields and different tree species and bushes). Multispectral high resolution images were taken by two digital compact cameras: a Pentax Optio A40 for RGB photos and a Sigma DP1 modified to acquire the NIR band. Then, some tests were performed in order to analyze the UAV images' quality with both photogrammetric and photo-interpretation purposes, to validate the vector-sensor system, the image block geometry and to study the feasibility of tree species classification. Many pre-signalized Control Points were surveyed through GPS to allow accuracy analysis. Aerial Triangulations (ATs) were carried out with photogrammetric commercial software, Leica Photogrammetry Suite (LPS) and PhotoModeler, with manual or automatic selection of Tie Points, to pick out pros and cons of each package in managing non conventional aerial imagery as well as the differences in the modeling approach. Further analysis were done on the differences between the EO parameters and the corresponding data coming from the on board UAV navigation system.

  10. High speed, intermediate resolution, large area laser beam induced current imaging and laser scribing system for photovoltaic devices and modules

    Science.gov (United States)

    Phillips, Adam B.; Song, Zhaoning; DeWitt, Jonathan L.; Stone, Jon M.; Krantz, Patrick W.; Royston, John M.; Zeller, Ryan M.; Mapes, Meghan R.; Roland, Paul J.; Dorogi, Mark D.; Zafar, Syed; Faykosh, Gary T.; Ellingson, Randy J.; Heben, Michael J.

    2016-09-01

    We have developed a laser beam induced current imaging tool for photovoltaic devices and modules that utilizes diode pumped Q-switched lasers. Power densities on the order of one sun (100 mW/cm2) can be produced in a ˜40 μm spot size by operating the lasers at low diode current and high repetition rate. Using galvanostatically controlled mirrors in an overhead configuration and high speed data acquisition, large areas can be scanned in short times. As the beam is rastered, focus is maintained on a flat plane with an electronically controlled lens that is positioned in a coordinated fashion with the movements of the mirrors. The system can also be used in a scribing mode by increasing the diode current and decreasing the repetition rate. In either mode, the instrument can accommodate samples ranging in size from laboratory scale (few cm2) to full modules (1 m2). Customized LabVIEW programs were developed to control the components and acquire, display, and manipulate the data in imaging mode.

  11. Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, Marco [INFN, Ferrara, Italy

    2015-07-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to –25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

  12. Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, M., E-mail: contalbrigo@fe.infn.it

    2015-07-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to −25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

  13. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    International Nuclear Information System (INIS)

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30 μm for a bias increment of 0.2 V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity

  14. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Pettinari, G., E-mail: giorgio.pettinari@cnr.it [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); National Research Council (CNR), Institute for Photonics and Nanotechnologies (IFN-CNR), Via Cineto Romano 42, 00156 Roma (Italy); Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Patanè, A. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Polimeni, A.; Capizzi, M. [CNISM-Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy)

    2013-12-09

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30 μm for a bias increment of 0.2 V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  15. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    Science.gov (United States)

    Pettinari, G.; Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Polimeni, A.; Capizzi, M.; Patanè, A.

    2013-12-01

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30 μm for a bias increment of 0.2 V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  16. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Balkhab mineral district in Afghanistan: Chapter B in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Balkhab mineral district, which has copper deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2007,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS products match

  17. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Kandahar mineral district in Afghanistan: Chapter Z in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Kandahar mineral district, which has bauxite deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA,2006,2007,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS

  18. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Khanneshin mineral district in Afghanistan: Chapter A in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Khanneshin mineral district, which has uranium, thorium, rare-earth-element, and apatite deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2007,2008,2010), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be

  19. POLARIMETRIC SIGNATURES IDENTIFICATION FOR DIFFERENT FEATURES IN RADARSAT-2 POLSAR IMAGE: A CASE STUDY OF HALAYIB AREA, EGYPT

    Directory of Open Access Journals (Sweden)

    A. H. Nasr

    2016-06-01

    Full Text Available In fully polarized SAR (PolSAR data the returned signal from a target contains all polarizations. More information about this target may be inferred with respect to single-polarization. Distinct polarization separates targets due to its different backscattering responses. A Radarsat-2 PolSAR image acquired on December 2013 of part of Halayib area (Egypt was used in this study. Polarimetric signatures for various features (Wadi deposits, Tonalite, Chlorite schist, and Radar penetrated areas were derived and identified. Their Co-polarized and Cross-polarized signatures were generated, based on the calculation of the backscattered power at various ellipticity and orientation angles. Graphical 3D-representation of these features was provided and more details of their physical information are depicted according to their different polarization bases. The results illustrate that polarimetric signatures, obtained due to factors like surface roughness, dielectric constant and feature orientation, can be an effective representation for analyzing various features. The shape of the signature is significant and can also indicate the scattering mechanisms dominating the features response.

  20. Advantages of cluster analysis for multifunctional and intercrossing brain area distribution Evaluation by functional magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Hongchang Zhai; Xudong Xu; Shengyong Xiao

    2008-01-01

    BACKGROUND: Multiple linear regression, general linear test and calculation of correlation values are commonly used in studies of brain function using functional magnetic resonance imaging (fMRI). However, there are some limitations in their applications. In non-signal data statistics, cluster analysis functions as a very mature method, but it is not reliable in signal data statistics. OBJECTIVE: To investigate the spatial distribution of complex function in brain areas during motor tasks by cluster analysis, and to compare this with multiple linear regression. DESIGN, TIME AND SETTING: Block design, performed at the MR laboratory of Guangzhou University of Chinese Medicine. PARTICIPANTS: Fifteen right-handed, healthy university students (10 males and 5 females, aged 19-21 years).METHODS: fMRI was performed while the subjects performed a finger movement task with the right hand. The screen showed a gray hand, with red spots presented in a random order on one of the index, middle, ring and little fingers. The subjects were required to remember the sequence of the red spots on the display. After a delay of 14 seconds, the subjects tapped their fingers according to the order of the red spots, as soon as the red spots turned green. After an interval of 14 seconds, another sequence appeared. Every sequence lasted for 28 seconds, including preparation and execution phases. A total of nine sequences per subject were performed. The data were analyzed using deconvolution and cluster methods, and program "cluster" was used to statistically analyze the coordinate positions of deconvolution and cluster data. MAIN OUTCOME MEASURES: Brain activation maps by deconvolution and brain function maps by clustering of the maximum peak values; blood oxygenation level dependent curves by deconvolution; coordinates of peak values and activation volumes by the two methods. RESULTS: The deconvolution method could not integrate the brain activation maps during different tasks into one

  1. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Haji-Gak mineral district in Afghanistan: Chapter C in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Haji-Gak mineral district, which has iron ore deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA,2006,2007), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS products

  2. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Kharnak-Kanjar mineral district in Afghanistan: Chapter K in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Kharnak-Kanjar mineral district, which has mercury deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2007,2008,2010), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such

  3. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Herat mineral district in Afghanistan: Chapter T in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Arko, Scott A.; Harbin, Michelle L.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Herat mineral district, which has barium and limestone deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2007,2008,2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As

  4. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Zarkashan mineral district in Afghanistan: Chapter G in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Zarkashan mineral district, which has copper and gold deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2006,2007, 2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As

  5. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Farah mineral district in Afghanistan: Chapter FF in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Farah mineral district, which has spectral reflectance anomalies indicative of copper, zinc, lead, silver, and gold deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA, 2007, 2008, 2010), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that

  6. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Nalbandon mineral district in Afghanistan: Chapter L in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Nalbandon mineral district, which has lead and zinc deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA, 2007, 2008, 2010), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As

  7. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Panjsher Valley mineral district in Afghanistan: Chapter M in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Panjsher Valley mineral district, which has emerald and silver-iron deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA, 2009, 2010), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from

  8. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Kundalyan mineral district in Afghanistan: Chapter H in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Kundalyan mineral district, which has porphyry copper and gold deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As

  9. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Ghunday-Achin mineral district in Afghanistan, in Davis, P.A, compiler, Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Arko, Scott A.; Harbin, Michelle L.; Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Ghunday-Achin mineral district, which has magnesite and talc deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2008,2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As

  10. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Aynak mineral district in Afghanistan: Chapter E in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Aynak mineral district, which has copper deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA,2008,2010), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS

  11. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Badakhshan mineral district in Afghanistan: Chapter F in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Badakhshan mineral district, which has gold deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA,2007,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS products

  12. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Dusar-Shaida mineral district in Afghanistan: Chapter I in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Dusar-Shaida mineral district, which has copper and tin deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the

  13. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Katawas mineral district in Afghanistan: Chapter N in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Katawas mineral district, which has gold deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©AXA, 2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS products match JAXA

  14. Collagen proportionate area of liver tissue determined by digital image analysis in patients with HBV-related decompensated cirrhosis

    Institute of Scientific and Technical Information of China (English)

    Shi-BinXie; ChaoMa; Chao-ShuangLin; YingZhang; Jian-YunZhu; Wei-MinKe

    2011-01-01

    BACKGROUND: The accurate assessment of the degree of hepatic fibrosis plays a critical role in guiding the diagnosis, treatment and prognostic assessment of chronic liver diseases. Liver biopsy is currently the most reliable method to evaluate the severity of hepatic fibrosis. However, liver biopsy is an invasive procedure associated with morbidity and mortality, and has several limitations in patients with decompensated cirrhosis. There is no report on the collagen proportionate area (CPA) of liver tissue in the decompensated stage of cirrhosis. This study aimed to determine the CPA of resected liver tissue samples from patients with HBV-related decompensated cirrhosis using digital image analysis, and to analyze the relationship between the CPA and liver functional reserve. METHODS: Fifty-three resected liver tissue samples from liver transplant patients with chronic hepatitis B-induced decompensated cirrhosis were stained with Masson's trichrome, and the CPA in these samples was quantitatively determined using digital image analysis. The values of relevant liver function justbeforelivertransplantation,theCPAinlivertissue,andtheir correlationwereanalyzed. RESULTS: The mean CPA at the decompensated stage of cirrhosis was 35.93±14.42% (11.24%-63.41%). The correlation coefficients of the CPA with a model for end-stage liver disease score, serum total bilirubin and international standard ratio of prothrombin B were 0.553, 0.519 and 0.533, respectively (P CONCLUSIONS: The degree of fibrosis may be correlated with the functional reserve. With the advancement of fibrosis, the liver functional reserve is attenuated accordingly.

  15. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Tourmaline mineral district in Afghanistan: Chapter J in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.; Arko, Scott A.; Harbin, Michelle L.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Tourmaline mineral district, which has tin deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the DS products

  16. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Uruzgan mineral district in Afghanistan: Chapter V in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Uruzgan mineral district, which has tin and tungsten deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA, 2008, 2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such

  17. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the South Helmand mineral district in Afghanistan: Chapter O in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the South Helmand mineral district, which has travertine deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA, 2008, 2010), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such

  18. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Baghlan mineral district in Afghanistan: Chapter P in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Baghlan mineral district, which has industrial clay and gypsum deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA, 2006, 2007, 2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from

  19. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Bakhud mineral district in Afghanistan: Chapter U in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.; Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Bakhud mineral district, which has industrial fluorite deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2006,2007, 2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As

  20. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the North Takhar mineral district in Afghanistan: Chapter D in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the North Takhar mineral district, which has placer gold deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2006,2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such

  1. Chromatic X-Ray imaging with a fine pitch CdTe sensor coupled to a large area photon counting pixel ASIC

    CERN Document Server

    Bellazzini, R; Brez, A; Minuti, M; Pinchera, M; Mozzo, P

    2012-01-01

    An innovative X-ray imaging sensor with intrinsic digital characteristics is presented. It is based on Chromatic Photon Counting technology. The detector is able to count individually the incident X-ray photons and to separate them according to their energy (two 'color' images per exposure). The energy selection occurs in real time and at radiographic imaging speed (GHz global counting rate). Photon counting, color mode and a very high spatial resolution (more than 10 l.p./mm at MTF50) allow to obtain an optimal ratio between image quality and absorbed dose. The individual block of the imaging system is a two-side buttable semiconductor radiation detector made of a thin pixellated CdTe crystal (the sensor) coupled to a large area VLSI CMOS pixel ASIC. 1, 2, 4, 8 tile units have been built. The 8 tiles unit has 25cm x 2.5cm sensitive area. Results and images obtained from in depth testing of several configurations of the system are presented. The X-Ray imaging system is the technological platform of PIXIRAD Im...

  2. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Ghazni2 mineral district in Afghanistan: Chapter EE in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Ghazni2 mineral district, which has spectral reflectance anomalies indicative of gold, mercury, and sulfur deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA, 2008, 2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image

  3. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Ghazni1 mineral district in Afghanistan: Chapter DD in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Ghazni1 mineral district, which has spectral reflectance anomalies indicative of clay, aluminum, gold, silver, mercury, and sulfur deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA, 2008, 2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such

  4. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Dudkash mineral district in Afghanistan: Chapter R in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Arko, Scott A.; Harbin, Michelle L.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Dudkash mineral district, which has industrial mineral deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2006,2007,2008,2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS

  5. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Kunduz mineral district in Afghanistan: Chapter S in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Arko, Scott A.; Harbin, Michelle L.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Kunduz mineral district, which has celestite deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2007,2008,2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such, the

  6. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Parwan mineral district in Afghanistan: Chapter CC in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Parwan mineral district, which has gold and copper deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA,2006, 2007), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such

  7. A Preliminary Study to Forecast Japanese Encephalitis Vector Abundance in Paddy Growing Area, with the Aid of Radar Satellite Images.

    Science.gov (United States)

    Raju, K Hari Kishan; Sabesan, Shanmugavelu; Rajavel, Aladu Ramakrishnan; Subramanian, Swaminathan; Natarajan, Ramalingam; Thenmozhi, Velayutham; Tyagi, Brij Kishore; Jambulingam, Purushothaman

    2016-02-01

    Vector mosquitoes of Japanese encephalitis (JE) breed mostly in rice fields, and human cases occur scattered over extended rural rice-growing areas. From this, one may surmise an ecological connection with the irrigation facilities and paddy cultivation. Furthermore, it has been hypothesized that a particular stage of paddy growth is a premonitory sign that can lead to a markedly increased population of the vector mosquitoes. The present study aimed to forecast the vector abundance by monitoring the paddy growth using remote sensing and geographical information systems. The abundance of the JE vector Culex tritaeniorhynchus peaked when the paddy crop was at its heading stage and dipped when the crop reached the maturing stage. A significant positive correlation was observed between paddy growth and adult density (r = 0.73, p < 0.008). The sigma naught values (σ0) derived from satellite images of paddy fields ranged from -18.3 (during transplantation stage) to approximately -10 (during the noncultivation period). A significant positive correlation was observed between σ0 and paddy growth stages (r = 0.87, p < 0.05) and adult vector density (r = 0.74, p = 0.04). The σ0 value observed during the vegetative and flowering stages of paddy growth ranged from -17.6 to -17.16, at which period the vector density started building up. This could be the spectral signature that denotes the "risk," following which a high vector abundance is expected during heading stage of the paddy. PMID:26824289

  8. Debris-flows scale predictions based on basin spatial parameters calculated from Remote Sensing images in Wenchuan earthquake area

    International Nuclear Information System (INIS)

    Debris flow is a common hazard in the Wenchuan earthquake area. Collapse and Landslide Regions (CLR), caused by earthquakes, could be located from Remote Sensing images. CLR are the direct material source regions for debris flow. The Spatial Distribution of Collapse and Landslide Regions (SDCLR) strongly impact debris-flow formation. In order to depict SDCLR, we referred to Strahler's Hypsometric analysis method and developed 3 functional models to depict SDCLR quantitatively. These models mainly depict SDCLR relative to altitude, basin mouth and main gullies of debris flow. We used the integral of functions as the spatial parameters of SDCLR and these parameters were employed during the process of debris-flows scale predictions. Grouping-occurring debris-flows triggered by the rainstorm, which occurred on September 24th 2008 in Beichuan County, Sichuan province China, were selected to build the empirical equations for debris-flows scale predictions. Given the existing data, only debris-flows runout zone parameters (Max. runout distance L and Lateral width B) were estimated in this paper. The results indicate that the predicted results were more accurate when the spatial parameters were used. Accordingly, we suggest spatial parameters of SDCLR should be considered in the process of debris-flows scale prediction and proposed several strategies to prevent debris flow in the future

  9. Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2012-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This DS consists of the locally enhanced ALOS image mosaics for each of the 24 mineral project areas (referred to herein as areas of interest), whose locality names, locations, and main mineral occurrences are shown on the index map of Afghanistan (fig. 1). ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency, but the image processing has altered the original pixel structure and all image values of the JAXA

  10. Coastal Monitoring Using L-band Synthetic Aperture Radar (SAR) Image Data - Some Case Studies in Asian Delta Areas

    Science.gov (United States)

    Tanaka, A.

    2014-12-01

    Coastal geomorphology is highly variable as it is affected by sea-level changes and other naturally- and human-induced fluctuations. To effectively assess and monitor geomorphological changes in various time scales is thus critical for coastal management. Asian mega deltas are vulnerable to a sea-level rise due to its low-lying delta plain, and are dynamic region given a large amount of sediment supply. However, limited data availability and accessibility in the deltas have prevented establishment of systematic coastal monitoring. A variety of remote sensing systems can be used to monitor geomorphological changes in coastal areas as it has wide spatial coverage and high temporal repeatability. Especially, analysis using SAR (Synthetic Aperture Radar) data not affected by the cloud conditions offer potential for monitoring in the monsoon Asia region. We will present some case studies of Asian coastal regions using L-band SAR data, ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band SAR) and JERS-1 (Japanese Earth Resource Satellite-1) SAR data. One example is that time-series of radar amplitude images can be used to delineate changes quantitatively of the areal extent of river-mouth bars in distributaries of the Mekong River delta. It shows that the estimated areas of river mouthbars gradually increase on an annual time scale, and seasonal variations of areas were also recognized. Another example is that differential SAR interferometry is applied to the coast of the Yellow River delta in China. It shows very high subsidence rates, likely due to groundwater pumping. A further example is that we apply a SAR interferometry time series analysis to monitor ground deformations in the lower Chao Phraya delta plain, Thailand. A single reference time series interferogram from the stacking of unwrapped phases were applied. The subsidence and uplift pattern observed using the SAR interferometry time series analysis highlights the spatial complexity

  11. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Takhar mineral district in Afghanistan: Chapter Q in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.; Cagney, Laura E.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Takhar mineral district, which has industrial evaporite deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420–500 nanometer, nm), green (520–600 nm), red (610–690 nm), and near-infrared (760–890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520–770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency (©JAXA, 2008), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such that original image values cannot be recreated from this DS. As such

  12. Morphological image filtering for improvement of textural built-up index performances in case of presence of scattered vegetation in semi-desertic areas

    OpenAIRE

    Pesaresi, Martino; GERHARDINGER Andrea

    2009-01-01

    In this paper an improved procedure for the automatic recognition of built-up areas, using the so-called PANTEX index is presented. This index is based on analysis of image textural measures extracted using anisotropic rotation-invariant GLCM statistics. These measures may overestimate the built-up areas in case of presence of scattered vegetation having the same spatial pattern of settlements. In this paper we present a methodology able to overcome this problem. This methodology is based on ...

  13. A method for image segmentation based on star's area%一种基才星体面积的星图分割方法

    Institute of Scientific and Technical Information of China (English)

    邓江生; 樊利恒; 古立莉

    2012-01-01

    图像分割是图像识别过程中的关键一步,分割结果的好坏会直接影响到星体的细分定位和模式识别。星体在星图中属于小目标,多目标.其分割与普通图像的分割有较大的不同。文中在分析星图特点的基础上,提出了基于星体面积的分割方法,并通过仿真与其他分割方法进行比较,验证了其有效性和优越性。%Image segmentation is a key step in image recognition. The effects of sub pixel location and star pattern recognition are directly affected by the result of segmentation. Star target in a star image is a small one. There are lots of stars in a star image. Thus, the segmentation of star image has many differences from an ordinary image. In this article, after analyzing the characteristic of a star image, a new method of star image segmentation based on the star's area was put forward and its validity and advantage were proved after emulation.

  14. Impact of the number of registration points for replacement of three-dimensional computed tomography images in dental areas using three-dimensional light-scanned images of dental models

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the accuracy and reliability of registration methods for replacing dental areas of three-dimensional (3D) computed tomography (CT) images with 3D light-scanned dental images using tooth cusp tips and the occlusal surface. The number of registration points was investigated for its impact on the tooth cusp tip-based method. Computed tomography image data on ten skull models and light-scanned data from dental cast models of the skulls were registered with imaging registration software. The marker-free registration using tooth cusp tips involved five protocols identifying 3-14 points as registration references. The control registration protocol consisted of a surface-matching method that used the occlusal surface. Errors were measured between the reference data and the registered images at the mesial, distal, buccal, and lingual tooth surfaces. For image registration using dental cusp tips, the mean error ranged from 0.164 mm for seven points to 0.198 mm for 14 points. The error did not decrease with an increase in the number of registration points from three to 14. The use of dental cusp tips resulted in no significant error with respect to the number of registration points. Image registration using the occlusal surface yielded a mean error of 0.116 mm. Significant differences between the errors were observed in comparisons of the dental cusp tip and occlusal surface registrations. When positioning scanned dental images onto CT images, surface-based image registration using the occlusal surface gives less error than reference point-based image registration with dental cusp tips. We found no significant difference in the error with an increase in the number of registration points from three to 14. (author)

  15. Identification of the primary motor area by three-dimensional reconstruction of the corticospinal tract using diffusion tensor imaging

    Institute of Scientific and Technical Information of China (English)

    Guojun Deng; Luo Li; Guimei Chen; Erming Zeng; Xiangzuo Xiao; Meihua Li; Tao Hong; Donghai Li

    2011-01-01

    Functional MRI (fMRI) is widely used as a non-invasive method for the evaluation of pre-operation motor function. However, patients with cortical function impairment, such as those with hemiparesis, can rarely achieve hand clenching, a typical fMRI task for central sulcus identification, and the method is also of limited use in uncooperative children. Thus, it is important to develop a new method for identifying primary motor areas (PMA) in such individuals. This study used corticospinal tractography to identify the PMA in 20 patients with deep-seated brain tumor. Two regions of interest were set within the brainstem for corticospinal tract (CST) fiber tracking: one at the level of the pons and the other at the level of the cerebral peduncle. The CST fiber tracking results and fMRI activation signals were merged with three-dimensional anatomic MRI findings. The consistency of identifying the PMA by CST and fMRI was analyzed. fMRI activation signals were distributed mainly in the contralateral central sulcus around the omega-shaped hand knob. The CST consistently propagated from the pons and cerebral peduncle to the suspected PMA location. There was a good correlation between CST fiber tracking results and fMRI activation signals in terms of their abilities to identify the PMA. The differences between fMRI and CST fiber tracking findings may result from our functional task, which consisted only of hand movements. Our results indicate that diffusion tensor imaging is a useful brain mapping technique for identifying the PMA in paralyzed patients and uncooperative children.

  16. Image Quality of Coronary Computed Tomography Angiography with 320-Row Area Detector Computed Tomography in Children with Congenital Heart Disease.

    Science.gov (United States)

    Tada, Akihiro; Sato, Shuhei; Kanie, Yuichiro; Tanaka, Takashi; Inai, Ryota; Akagi, Noriaki; Morimitsu, Yusuke; Kanazawa, Susumu

    2016-03-01

    The objective of this study was to assess factors affecting image quality of 320-row computed tomography angiography (CTA) of coronary arteries in children with congenital heart disease (CHD). We retrospectively reviewed 28 children up to 3 years of age with CHD who underwent prospective electrocardiography (ECG)-gated 320-row CTA with iterative reconstruction. We assessed image quality of proximal coronary artery segments using a five-point scale. Age, body weight, average heart rate, and heart rate variability were recorded and compared between two groups: patients with good diagnostic image quality in all four coronary artery segments and patients with at least one coronary artery segment with nondiagnostic image quality. Altogether, 96 of 112 segments (85.7 %) had diagnostic-quality images. Patients with nondiagnostic segments were significantly younger (10.0 ± 11.6 months) and had lower body weight (5.9 ± 2.9 kg) (each p heart rate and heart rate variability between the two imaging groups were not significant. Receiver operating characteristic analyses for predicting patients with nondiagnostic image quality revealed an optimal body weight cutoff of ≤5.6 kg and an optimal age cutoff of ≤12.5 months. Prospective ECG-gated 320-row CTA with iterative reconstruction provided feasible image quality of coronary arteries in children with CHD. Younger age and lower body weight were factors that led to poorer image quality of coronary arteries.

  17. Cryogenic phased-array for high resolution magnetic resonance imaging (MRI); assessment of clinical and research applications

    Science.gov (United States)

    Ip, Flora S.

    Magnetic Resonance (MR) imaging is one of the most powerful tools in diagnostic medicine for soft tissue imaging. Image acquisition techniques and hardware receivers are very important in achieving high contrast and high resolution MR images. An aim of this dissertation is to design single and multi-element room and cryogenic temperature arrays and make assessments of their signal-to-noise ratio (SNR) and SNR gain. In this dissertation, four sets of MR receiver coils are built. They are the receiver-only cryo-coils that are not commercially available. A tuning and matching circuit is attached to each coil. The tuning and matching circuits are simple; however, each device component has to operate at a high magnetic field and cryogenic temperature environment. Remote DC bias of the varactor controls the tuning and matching outside the scanner room. Active detuning of the resonator is done by two p-i-n junction (PIN) diodes. Cooling of the receiver is done by a customized liquid nitrogen cryostat. The first application is to build a 3-Tesla 2x1 horseshoe counter-rotating current (CRC) cryogenic array to image the tibia in a human body. With significant increase in SNR, the surface coil should deliver high contrast and resolution images that can show the trabecular bone and bone marrow structure. This structural image will be used to model the mechanical strength of the bone as well as bone density and chance of fracture. The planar CRC is a unique design of this surface array. The second application is to modify the coil design to 7-Tesla to study the growth of infant rhesus monkey eyes. Fast scan MR images of the infant monkey heads are taken for monitoring shapes of their eyeballs. The monkeys are induced with shortsightedness by eye lenses, and they are scanned periodically to get images of their eyeballs. The field-of-view (FOV) of these images is about five centimeters and the area of interest is two centimeters deep from the surface. Because of these reasons

  18. Computed tomography (CT) of cervical lymph nodes in patients with oral cancer. Comparison of low-attenuation areas in lymph nodes on CT images with pathological findings

    International Nuclear Information System (INIS)

    The objective of this study was to clarify the histopathological features of low-attenuation areas in computed tomography (CT) images of cervical metastatic and benign lymph nodes in patients with oral squamous cell carcinoma (SCC). CT images of 230 lymph nodes from 37 patients with oral SCC were classified into four categories and compared with histopathological findings. Metastatic lymph nodes were evaluated in terms of focal necrosis, keratinization, fibrous tissue, and the proportion of the lymph node showing focal necrosis. Benign lymph nodes were evaluated in terms of adipose tissue, follicular hyperplasia, sinus histiocytosis, hyperemia, focal hemorrhaging, and the amount of adipose tissue. Histopathologically, all 13 metastatic lymph nodes with rim enhancement on CT images included focal necrosis. However, most of the lymph nodes showed no focal necrosis. In addition, tumor cells, keratinization, and fibrous tissue were observed in the lymph nodes. Of the 26 metastatic lymph nodes with a heterogeneous appearance on CT images, four did not show focal necrosis. These lymph nodes showed keratinization or accumulation of lymph fluid. Histopathologically, 20 of 24 benign lymph nodes with a heterogeneous appearance on CT images (83.3%) had accompanying adipose tissue. Focal necrosis was the most important factor contributing to low attenuation in metastatic lymph nodes. However, other factors, such as tumor cells, keratinization, fibrous tissue, and accumulation of lymph fluid, also contributed. In benign lymph nodes, the presence of adipose tissue was a contributing factor in low-attenuation areas, as was focal hemorrhaging. (author)

  19. Optical imaging of resonant electrical carrier injection into individual quantum dots

    OpenAIRE

    A. Baumgartner; Stock, E; Patanè, A.; Eaves, L.; Henini, M.; Bimberg, D.

    2010-01-01

    We image the micro-electroluminescence (EL) spectra of self-assembled InAs quantum dots (QDs) embedded in the intrinsic region of a GaAs p-i-n diode and demonstrate optical detection of resonant carrier injection into a single QD. Resonant tunneling of electrons and holes into the QDs at bias voltages below the flat-band condition leads to sharp EL lines characteristic of individual QDs, accompanied by a spatial fragmentation of the surface EL emission into small and discrete light- emitting ...

  20. Web Based Rapid Mapping of Disaster Areas using Satellite Images, Web Processing Service, Web Mapping Service, Frequency Based Change Detection Algorithm and J-iView

    Science.gov (United States)

    Bandibas, J. C.; Takarada, S.

    2013-12-01

    Timely identification of areas affected by natural disasters is very important for a successful rescue and effective emergency relief efforts. This research focuses on the development of a cost effective and efficient system of identifying areas affected by natural disasters, and the efficient distribution of the information. The developed system is composed of 3 modules which are the Web Processing Service (WPS), Web Map Service (WMS) and the user interface provided by J-iView (fig. 1). WPS is an online system that provides computation, storage and data access services. In this study, the WPS module provides online access of the software implementing the developed frequency based change detection algorithm for the identification of areas affected by natural disasters. It also sends requests to WMS servers to get the remotely sensed data to be used in the computation. WMS is a standard protocol that provides a simple HTTP interface for requesting geo-registered map images from one or more geospatial databases. In this research, the WMS component provides remote access of the satellite images which are used as inputs for land cover change detection. The user interface in this system is provided by J-iView, which is an online mapping system developed at the Geological Survey of Japan (GSJ). The 3 modules are seamlessly integrated into a single package using J-iView, which could rapidly generate a map of disaster areas that is instantaneously viewable online. The developed system was tested using ASTER images covering the areas damaged by the March 11, 2011 tsunami in northeastern Japan. The developed system efficiently generated a map showing areas devastated by the tsunami. Based on the initial results of the study, the developed system proved to be a useful tool for emergency workers to quickly identify areas affected by natural disasters.

  1. Correlation between the Effects of Acupuncture at Taichong (LR3) and Functional Brain Areas: A Resting-State Functional Magnetic Resonance Imaging Study Using True versus Sham Acupuncture

    OpenAIRE

    Chunxiao Wu; Shanshan Qu; Jiping Zhang; Junqi Chen; Shaoqun Zhang; Zhipeng Li; Jiarong Chen; Huailiang Ouyang; Yong Huang; Chunzhi Tang

    2014-01-01

    Functional magnetic resonance imaging (fMRI) has been shown to detect the specificity of acupuncture points, as proved by numerous studies. In this study, resting-state fMRI was used to observe brain areas activated by acupuncture at the Taichong (LR3) acupoint. A total of 15 healthy subjects received brain resting-state fMRI before acupuncture and after sham and true acupuncture, respectively, at LR3. Image data processing was performed using Data Processing Assistant for Resting-State fMRI ...

  2. Comparison of data and spectral driven methods for kaolinite-bearing area mapping in Masahim volcano, using Hyperion images

    Directory of Open Access Journals (Sweden)

    Bahram Bahrambeygi

    2012-10-01

    Full Text Available Hyperion hyperspectral data contains a very rich source of information from the Earth surface that collects 242 narrow contiguous spectral bands. Achieving this source of rich information is subject to the performance of suitable image processing methods on raw satellite data. Satellite image processing methods can be classified into two categories of statistical-based and spectral-based. In the statistical-based methods, processing principle is based on the distribution pattern of pixels’ DN values around mean, mode and median in DN value histogram of each band. However, in the spectral-based methods, the analysis is performed based on the spectral properties of the materials under question. In this study, we investigated both image processing methods and validated the results with field and laboratory data. Field and laboratory studies included the investigation of field samples, laboratory spectroradiometry, XRD analysis and thin section studies of the rock samples. SAM and PCA image processing methods performed on Hyperion images of the argillic zone in Masahim volcanic crater as spectral and statistical-based methods, respectively. The MTMF method also was surveyed as a composite method in addition to the use of reference spectrum using statistical principles. Confusion matrix prepared for the results of the three methods illustrated producer accuracy of 74.58% for SAM, 25.42% for PCA and 61% for MTMF results. Therefore, use of spectral-based methods on hyperspectral image processing is considered as a suitable way for ground surface remote sensing studies using hyperspectral Hyperion images.

  3. Identification of Structurally Damaged Areas in Airborne Oblique Images Using a Visual-Bag-of-Words Approach

    Directory of Open Access Journals (Sweden)

    Anand Vetrivel

    2016-03-01

    Full Text Available Automatic post-disaster mapping of building damage using remote sensing images is an important and time-critical element of disaster management. The characteristics of remote sensing images available immediately after the disaster are not certain, since they may vary in terms of capturing platform, sensor-view, image scale, and scene complexity. Therefore, a generalized method for damage detection that is impervious to the mentioned image characteristics is desirable. This study aims to develop a method to perform grid-level damage classification of remote sensing images by detecting the damage corresponding to debris, rubble piles, and heavy spalling within a defined grid, regardless of the aforementioned image characteristics. The Visual-Bag-of-Words (BoW is one of the most widely used and proven frameworks for image classification in the field of computer vision. The framework adopts a kind of feature representation strategy that has been shown to be more efficient for image classification—regardless of the scale and clutter—than conventional global feature representations. In this study supervised models using various radiometric descriptors (histogram of gradient orientations (HoG and Gabor wavelets and classifiers (SVM, Random Forests, and Adaboost were developed for damage classification based on both BoW and conventional global feature representations, and tested with four datasets. Those vary according to the aforementioned image characteristics. The BoW framework outperformed conventional global feature representation approaches in all scenarios (i.e., for all combinations of feature descriptors, classifiers, and datasets, and produced an average accuracy of approximately 90%. Particularly encouraging was an accuracy improvement by 14% (from 77% to 91% produced by BoW over global representation for the most complex dataset, which was used to test the generalization capability.

  4. Normal Anatomy and Compression Areas of Nerves of the Foot and Ankle: US and MR Imaging with Anatomic Correlation.

    Science.gov (United States)

    De Maeseneer, Michel; Madani, Hardi; Lenchik, Leon; Kalume Brigido, Monica; Shahabpour, Maryam; Marcelis, Stefaan; de Mey, Johan; Scafoglieri, Aldo

    2015-01-01

    The anatomy of the nerves of the foot and ankle is complex, and familiarity with the normal anatomy and course of these nerves as well as common anatomic variants is essential for correct identification at imaging. Ultrasonography (US) and magnetic resonance (MR) imaging allow visualization of these nerves and may facilitate diagnosis of various compression syndromes, such as "jogger's heel," Baxter neuropathy, and Morton neuroma. It may be difficult to distinguish the nerves from adjacent vasculature at MR imaging, and US can help in differentiation. The authors review the normal anatomy and common variants of the nerves of the foot and ankle, with use of dissected specimens and correlative US and MR imaging findings. In addition, the authors illustrate proper probe positioning, which is essential for visualizing the nerves at US. The authors' discussion focuses on the superficial and deep peroneal, sural, saphenous, tibial, medial and lateral plantar, medial and inferior calcaneal, common digital, and medial proper plantar digital nerves.

  5. Normal Anatomy and Compression Areas of Nerves of the Foot and Ankle: US and MR Imaging with Anatomic Correlation.

    Science.gov (United States)

    De Maeseneer, Michel; Madani, Hardi; Lenchik, Leon; Kalume Brigido, Monica; Shahabpour, Maryam; Marcelis, Stefaan; de Mey, Johan; Scafoglieri, Aldo

    2015-01-01

    The anatomy of the nerves of the foot and ankle is complex, and familiarity with the normal anatomy and course of these nerves as well as common anatomic variants is essential for correct identification at imaging. Ultrasonography (US) and magnetic resonance (MR) imaging allow visualization of these nerves and may facilitate diagnosis of various compression syndromes, such as "jogger's heel," Baxter neuropathy, and Morton neuroma. It may be difficult to distinguish the nerves from adjacent vasculature at MR imaging, and US can help in differentiation. The authors review the normal anatomy and common variants of the nerves of the foot and ankle, with use of dissected specimens and correlative US and MR imaging findings. In addition, the authors illustrate proper probe positioning, which is essential for visualizing the nerves at US. The authors' discussion focuses on the superficial and deep peroneal, sural, saphenous, tibial, medial and lateral plantar, medial and inferior calcaneal, common digital, and medial proper plantar digital nerves. PMID:26284303

  6. A methodology for near real-time change detection between Unmanned Aerial Vehicle and wide area satellite images

    Science.gov (United States)

    Fytsilis, Anastasios L.; Prokos, Anthony; Koutroumbas, Konstantinos D.; Michail, Dimitrios; Kontoes, Charalambos C.

    2016-09-01

    In this paper a novel integrated hybrid methodology for unsupervised change detection between Unmanned Aerial Vehicle (UAV) and satellite images, which can be utilized in various fields like security applications (e.g. border surveillance) and damage assessment, is proposed. This is a challenging problem mainly due to the difference in geographic coverage and the spatial resolution of the two images, as well as to the acquisition modes which lead to misregistration errors. The methodology consists of the following steps: (a) pre-processing, where the part of the satellite image that corresponds to the UAV image is determined and the UAV image is ortho-rectified using information provided by a Digital Terrain Model, (b) the detection of potential changes, which is based exclusively on intensity and image gradient information, (c) the generation of the region map, where homogeneous regions are produced by the previous potential changes via a seeded region growing algorithm and placed on the region map, and (d) the evaluation of the above regions, in order to characterize them as true changes or not. The methodology has been applied on demanding real datasets with very encouraging results. Finally, its robustness to the misregistration errors is assessed via extensive experimentation.

  7. AN EFFICIENT LARGE-AREA IMAGE INPAINTING ALGORITHM%一种有效的大区域图像修复算法

    Institute of Scientific and Technical Information of China (English)

    王战; 韩诚山; 李祥之; 黄良

    2015-01-01

    For the optimisation of image inpainting,ordinary non-texture image inpainting or texture synthesis algorithm can’t perform very well in repairing the natural image with large area as the inpainting area.Traditional CPT algorithm presents a very good thought to tackle the natural image inpainting,it combines the texture synthesis with non-texture image inpainting,and improves the effectiveness of inpainting process by using the iterative algorithm and carry out block matching each time on the point with highest priority,but the deficiency cannot be fully excluded.This paper proposes an effective large-area image inpainting algorithm by analysing the problems existed in CPT algorithm and making the enrichment and improvement under its framework.In addition it also gives a novel gradient-priority calculation method.This algorithm turns out to be effective by experiment in improving the quality of large-area images inpainting.%关于图像修复优化,普通的非纹理图像修复或纹理综合算法都不能对修复区域为大区域的自然图像取得很好的修复结果,传统的 CPT 算法提出了一种很好的解决自然图像修复思路,结合纹理综合和非纹理修复的方法,采用迭代算法,每次对优先权最高的一点进行块匹配,以此来提高修复过程的有效性,但也存在不足。通过对 CPT 算法存在的问题进行分析,并在其框架下进行充实和改进,提出一种有效的大区域图像修复算法,并给出一种全新的梯度优先的计算方法。实验证明该方法是有效的,提高了大区域图像修复效果。

  8. Dissociable effects of natural image structure and color on LFP and spiking activity in the lateral prefrontal cortex and extrastriate visual area V4

    OpenAIRE

    Liebe, Stefanie; Logothetis, Nikos K.; Rainer, Gregor

    2011-01-01

    Visual perception is mediated by unique contributions of the numerous brain regions that constitute the visual system. We performed simultaneous recordings of local field potentials (LFPs) and single unit activity (SUA) in areas V4 and lateral prefrontal cortex to characterize their contribution to visual processing. Here, we trained monkeys to identify natural images at different degradation levels in a visual recognition task. We parametrically varied color and structural information of nat...

  9. Spatial Enhancement of MODIS-based Images of Leaf Area Index: Application to the Boreal Forest Region of Northern Alberta, Canada

    OpenAIRE

    Charles P.-A. Bourque; Hassan, Quazi K.

    2010-01-01

    Leaf area index (LAI) is one of the most commonly used ecological variables in describing forests. Since 2000, 1-km resolution Moderate Resolution Imaging Spectroradiometer (MODIS)-based 8-day composites of LAI have been operationally available from the National Aeronautics and Space Administration (NASA), USA, at no cost to the user. In this paper, we present a simple protocol to enhance the spatial resolution of NASA-produced LAI composites to 250-m resolution. This is done by fusing MODIS-...

  10. Artificial intelligence systems for rainy areas detection and convective cells' delineation for the south shore of Mediterranean Sea during day and nighttime using MSG satellite images

    Science.gov (United States)

    Tebbi, Mohsene Abdelfettah; Haddad, Boualem

    2016-09-01

    The aim of this study is to investigate the potential of cloud classification by means of support vector machines using high resolution images from northern Algeria. The images were taken from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board of the Meteosat Second Generation (MSG) satellite. An automatic system was developed to operate during both day and nighttime by following two steps of data processing. The first aims to detect rainy areas in cloud systems, whereas the second delineates convective cells from stratiform ones. A set of 12 spectral parameters was selected to extract information about cloud properties, which are different from day to night. The training and validation steps of this study were performed by in-situ rainfall measurement data, collected during the rainy season of years 2011 and 2012 via automatic rain gauge stations distributed in northern Algeria. Artificial neural networks (ANNs) and support vector machine (SVM) were explored, by combining spectral parameters derived from MSG images. Better performances were obtained by the SVM classifier, in terms of Critical Success Index and Probability of Detection for rainy areas detection (CSI = 0.81, POD = 91%), and also for convective/stratiform delineation (CSI = 0.55, POD = 74%).

  11. Development of a large-area CMOS-based detector for real-time x-ray imaging

    Science.gov (United States)

    Heo, Sung Kyn; Park, Sung Kyu; Hwang, Sung Ha; Im, Dong Ak; Kosonen, Jari; Kim, Tae Woo; Yun, Seungman; Kim, Ho Kyung

    2010-04-01

    Complementary metal-oxide-semiconductor (CMOS) active pixel sensors (APSs) with high electrical and optical performances are now being attractive for digital radiography (DR) and dental cone-beam computed tomography (CBCT). In this study, we report our prototype CMOS-based detectors capable of real-time imaging. The field-of-view of the detector is 12 × 14.4 cm. The detector employs a CsI:Tl scintillator as an x-ray-to-light converter. The electrical performance of the CMOS APS, such as readout noise and full-well capacity, was evaluated. The x-ray imaging characteristics of the detector were evaluated in terms of characteristic curve, pre-sampling modulation transfer function, noise power spectrum, detective quantum efficiency, and image lag. The overall performance of the detector is demonstrated with phantom images obtained for DR and CBCT applications. The detailed development description and measurement results are addressed. With the results, we suggest that the prototype CMOS-based detector has the potential for CBCT and real-time x-ray imaging applications.

  12. The inappropriate use of lumbar magnetic resonance imaging in a health service area; Utilizacion inapropiada de la resonancia magnetica lumbar en un area de salud

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Recio, F. J.; Sanz, J. C.; Vera, S. [Hospital General de Soria (Spain); Peiro, S. [Fundacion de Investigacion en Servicios de Salud Valencia (Spain)

    1999-07-01

    To identify the percentage of inappropriate lumbar spine magnetic resonance imaging in the Soria Health Service, to quantify the costs and the possible association between inadequate use, the characteristics of the patient and the services requested. A descriptive study of the inappropriate use of MRI of the lumbar spine, taken from the retrospective examination, carried out by a radiologist, of the 233 MRI's requested between 1995 and 1998. For the valuation, the criteria of the American College of Radiology (ACR) and the Basque Agency for the Evaluation of Technologies (OSTEBA) were used. All the MRI's were carried out at an approved centre, the costs were calculated taken form the expenses paid by the Insalud, including the transport costs, calculated at prices applicable for the year in question. 11.7% of the studies were values as inappropriate, 2.1% debatable and the remainder adequate according to the ACR criteria, concentrating the inadequacy on studies for lumbago, that reached 80% of the inappropriate requests. The ACR and OSTEBA criteria coincided to a high degree (kappa statistics: 0.87). The expense related to the unnecessary studies was a litter higher than a million pesetas. No differences were found in the proportion of inappropriate studies according to the characteristics of the patient or the service requested, except the one already mentioned for the supposition diagnosis. Although the results of the study cannot be generalised to other environments, they suggest the possibility of a significant proportion of inappropriate use of lumbar spine MRI that could have an important repercussion on health care expenses. (Author) 11 refs.

  13. Local-area-enhanced, 2.5-meter resolution natural-color and color-infrared satellite-image mosaics of the Ghazni1 mineral district in Afghanistan: Chapter DD in Local-area-enhanced, high-resolution natural-color and color-infrared satellite-image mosaics of mineral districts in Afghanistan

    Science.gov (United States)

    Davis, Philip A.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Defense Task Force for Business and Stability Operations, prepared databases for mineral-resource target areas in Afghanistan. The purpose of the databases is to (1) provide useful data to ground-survey crews for use in performing detailed assessments of the areas and (2) provide useful information to private investors who are considering investment in a particular area for development of its natural resources. The set of satellite-image mosaics provided in this Data Series (DS) is one such database. Although airborne digital color-infrared imagery was acquired for parts of Afghanistan in 2006, the image data have radiometric variations that preclude their use in creating a consistent image mosaic for geologic analysis. Consequently, image mosaics were created using ALOS (Advanced Land Observation Satellite; renamed Daichi) satellite images, whose radiometry has been well determined (Saunier, 2007a,b). This part of the DS consists of the locally enhanced ALOS image mosaics for the Ghazni1 mineral district, which has spectral reflectance anomalies indicative of clay, aluminum, gold, silver, mercury, and sulfur deposits. ALOS was launched on January 24, 2006, and provides multispectral images from the AVNIR (Advanced Visible and Near-Infrared Radiometer) sensor in blue (420-500 nanometer, nm), green (520-600 nm), red (610-690 nm), and near-infrared (760-890 nm) wavelength bands with an 8-bit dynamic range and a 10-meter (m) ground resolution. The satellite also provides a panchromatic band image from the PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor (520-770 nm) with the same dynamic range but a 2.5-m ground resolution. The image products in this DS incorporate copyrighted data provided by the Japan Aerospace Exploration Agency ((c)JAXA, 2008, 2009), but the image processing has altered the original pixel structure and all image values of the JAXA ALOS data, such

  14. 北京平原造林地Pleiades卫星影像融合评价%Evaluation on Pleiades Satellite Image Fusion for Beijing Plain Afforested Area

    Institute of Scientific and Technical Information of China (English)

    董熙; 李存军; 夏朝宗; 王二丽; 杨新兵; 周静平; 胡海棠

    2016-01-01

    Eight different image fusion methods were adopted,including the CN spectrum fusion,PCA principal component transformation,Brovey transform,HCS transform,HPF high-pass filter transform, PanSharpen transformation,GS spectrum sharpening,based on a brightness control SFIM smoothing,to fuse the Pleiades satellite panchromatic and multi-spectral image of forest in Cai jiahe basin plain affor-estated area,Yanqing county,Beijing.The qualitative and quantitative result of remote sensing image fu-sion on spectral fidelity was analyzed,and the accuracy of automatic identification forest trees in the arti-ficial planting area using fused image was evaluated.Results show that the eight kinds of image fusion methods have their own advantages,but the HCS fusion method is simple,the remote sensing image spectral fidelity,artificial planting area of forests automatic identification precision is highest.So it is a suitable method for the Pleiades satellite images fusion to monitor forest.%通过CN波谱融合、PCA主成份变换、Brovey变换、HCS 变换、HPF 高通滤波变换、PanSharpen 变换、GS光谱锐化、SFIM基于亮度调节的平滑滤波等8种不同的遥感影像融合方法,对北京市延庆县蔡家河流域平原造林地的Pleiades卫星全色和多光谱影像进行融合,通过定性和定量方法从光谱保真、人工造林地林木自动识别精度等方面评价遥感影像融合效果。结果表明:8种影像融合方法各有优势,其中HCS融合方法操作简便,产生的遥感图像光谱保真强,人工造林地林木自动识别精度高,是一种适于Pleiades卫星影像进行林地监测的较好融合方法。

  15. Intact plant magnetic resonance imaging to study dynamics in long-distance sap flow and flow-conducting surface area

    NARCIS (Netherlands)

    Scheenen, T.W.J.; Vergeldt, F.J.; Heemskerk, A.M.; As, van H.

    2007-01-01

    Due to the fragile pressure gradients present in the xylem and phloem, methods to study sap flow must be minimally invasive. Magnetic resonance imaging (MRI) meets this condition. A dedicated MRI method to study sap flow has been applied to quantify long-distance xylem flow and hydraulics in an inta

  16. Intact plant magnetic resonance imaging to study dynamics in long-distance sap flow and flow-conducting surface area.

    NARCIS (Netherlands)

    Scheenen, T.W.J.; Vergeldt, F.J.; Heemskerk, A.M.; As, H. van

    2007-01-01

    Due to the fragile pressure gradients present in the xylem and phloem, methods to study sap flow must be minimally invasive. Magnetic resonance imaging (MRI) meets this condition. A dedicated MRI method to study sap flow has been applied to quantify long-distance xylem flow and hydraulics in an inta

  17. NOAA TIFF Image - 4m Multibeam Backscatter for Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Multibeam Backscatter GeoTiffs with 4x4 meter cell resolution describing the geomorphology of 15 areas along the shelf edge off the...

  18. NOAA TIFF Image - 4m Bathymetric Profile Curvature of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Profile Curvature GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off...

  19. NOAA TIFF Image - 4m Bathymetric Depth of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Depth GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the South...

  20. NOAA TIFF Image - 4m Bathymetric Depth Range of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Depth Range GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the...

  1. NOAA TIFF Image - 4m Bathymetric Slope of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Slope GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the South...

  2. NOAA TIFF Image - 4m Bathymetric Plan Curvature of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Plan Curvature GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the...

  3. NOAA TIFF Image - 4m Bathymetric Rugosity of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Rugosity GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the South...

  4. NOAA TIFF Image - 4m Bathymetric Mean Depth of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Mean Depth GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the...

  5. NOAA TIFF Image - 4m Bathymetric Curvature of Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Curvature GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the South...

  6. NOAA TIFF Image - 4m Sun Illuminated Bathymetry for Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Sun Illuminated Bathymetry GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the...

  7. NOAA TIFF Image - 4m Bathymetric Slope of Slope for Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Bathymetric Slope of Slope GeoTiffs with 4x4 meter cell resolution describing the topography of 15 areas along the shelf edge off the...

  8. NOAA TIFF Image - 3m Bathymetry Slope, Florida Deep Coral Areas - Lost Coast Explorer - (2010), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 3x3 meter cell size representing the slope (in degrees) of several deep coral priority areas off the Atlantic Coast of...

  9. Coral reef ecosystem marine protected area monitoring in Fagamalo, American Samoa: benthic images collected during belt transect surveys in 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 2010 the village of Fagamalo, Tutuila, American Samoa, designated a no-take Marine Protected Area that sees the protection of 2.25 square kilometers of ocean....

  10. NOAA TIFF Image - 3m Bathymetry, Florida Deep Coral Areas (Jacksonville) - Lost Coast Explorer - (2010), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 3x3 meter cell size representing bathymetry of several deep coral priority areas off the Atlantic Coast of Florida,...

  11. Application of 3D Scanned Imaging Methodology for Volume, Surface Area, and Envelope Density Evaluation of Densified Biomass

    Science.gov (United States)

    Measurement of surface area, volume, and density is an essential for quantifying, evaluating, and designing the biomass densification, storage, and transport operations. Acquiring accurate and repeated measurements of these parameters for hygroscopic densified biomass are not straightforward and on...

  12. NOAA TIFF Image - 3m Backscatter Mosaic, Florida Deep Coral Areas - Lost Coast Explorer - (2010), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 3x3 meter cell size representing the backscatter (intensity) of several deep coral priority areas off the Atlantic...

  13. Measurement of the cross-sectional area of the dural tube in the lumbar spine on magnetic resonance imaging. Comparison between normal, pre- and post-discectomy conditions

    Energy Technology Data Exchange (ETDEWEB)

    Matsubayashi, Yasutomo [Juntendo Univ., Tokyo (Japan). School of Medicine

    1997-07-01

    This study evaluated the usefulness of pre- and postoperative magnetic resonance imaging (MRI) of lumbar disc hernia with special attention to measurement of the cross-sectional area of the dural tube. Twenty-five patients (20 men and 5 women; 25 discs) who underwent posterior lumbar discectomy and 73 normal individuals (44 men and 29 women; 219 discs) of a similar age distribution were studied. Axial MRI was mainly used for the measurement of the dural tube. In the patient group, MRI examination was performed 1, 3, 6, and 12 months postoperatively. Assessment of the clinical symptoms was also included and used for comparison with the MRI evaluation. The cross-sectional area was significantly reduced to about 50% of the normal preoperatively. One month postoperatively, there was no significant increase in the size of the area, but after three months, the area increased significantly and progressed to the normal size within a year. One-month postoperatively, MRI examination was not considered useful because of postoperative hematoma and/or edema at the surgical site. The increase in the size of the cross-sectional area of the dural tube correlated well with the improvement in clinical symptoms. Three-months postoperatively, MRI evaluation of the lumbar disc seemed useful and measurement of the cross-sectional area of the dural tube appeared to serve as an indicator of the effectiveness of the surgery. (author)

  14. Generation of Land Cover Maps through the Fusion of Aerial Images and Airborne LiDAR Data in Urban Areas

    Directory of Open Access Journals (Sweden)

    Yongmin Kim

    2016-06-01

    Full Text Available Satellite images and aerial images with high spatial resolution have improved visual interpretation capabilities. The use of high-resolution images has rapidly grown and has been extended to various fields, such as military surveillance, disaster monitoring, and cartography. However, many problems were encountered in which one object has a variety of spectral properties and different objects have similar spectral characteristics in terms of land cover. The problems are quite noticeable, especially for building objects in urban environments. In the land cover classification process, these issues directly decrease the classification accuracy by causing misclassification of single objects as well as between objects. This study proposes a method of increasing the accuracy of land cover classification by addressing the problem of misclassifying building objects through the output-level fusion of aerial images and airborne Light Detection and Ranging (LiDAR data. The new method consists of the following three steps: (1 generation of the segmented image via a process that performs adaptive dynamic range linear stretching and modified seeded region growth algorithms; (2 extraction of building information from airborne LiDAR data using a planar filter and binary supervised classification; and (3 generation of a land cover map using the output-level fusion of two results and object-based classification. The new method was tested at four experimental sites with the Min-Max method and the SSI-nDSM method followed by a visual assessment and a quantitative accuracy assessment through comparison with reference data. In the accuracy assessment, the new method exhibits various advantages, including reduced noise and more precise classification results. Additionally, the new method improved the overall accuracy by more than 5% over the comparative evaluation methods. The high and low patterns between the overall and building accuracies were similar. Thus, the new

  15. 3D electrical image in area contaminated by hydrocarbons at the Cubatao, Brazil, industrial pole; Imageamento eletrico 3D em area contaminada por hidrocarbonetono no polo industrial de Cubatao - SP, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Baessa, Marcus Paulus Martins [Centro de Pesquisas e Desenvolvimento Leopoldo Americo Miguez de Mello, CENPES, Rio de Janeiro, RJ (Brazil)], E-mail: marcus.baessa@petrobras.br; Oliva, Andresa; Kiang, Chang Hung [Universidade Estadual Paulista, UNESP, Rio Claro, SP (Brazil)], E-mails: aoliva@rc.unesp.br, chang@rc.unesp.br

    2010-12-15

    This work presents the results of geophysical surveys performed over an oil contaminated site in the Polo Industrial de Cubatao - Sao Paulo. The aim is to characterize geoelectrical signatures associated to hydrocarbon presence in order to delimit and calculate the volume of the contaminated area. For this study were used Vertical Electrical Sounding (VES) and 3D Electrical Imaging for characterization of geology and geoelectrical response of the contaminant. The results showed that the hydrocarbon presence is associated to conductive anomalies due to products from biodegradation. The conductive anomalies are disseminated over the area, totalizing 1365.3 m3 volume. This volume, however, corresponds only to the residual phase contaminants, since it was not possible to map free-phase hydrocarbons. (author)

  16. Dissociable effects of natural image structure and color on LFP and spiking activity in the lateral prefrontal cortex and extrastriate visual area V4.

    Science.gov (United States)

    Liebe, Stefanie; Logothetis, Nikos K; Rainer, Gregor

    2011-07-13

    Visual perception is mediated by unique contributions of the numerous brain regions that constitute the visual system. We performed simultaneous recordings of local field potentials (LFPs) and single unit activity (SUA) in areas V4 and lateral prefrontal cortex to characterize their contribution to visual processing. Here, we trained monkeys to identify natural images at different degradation levels in a visual recognition task. We parametrically varied color and structural information of natural images while the animals were performing the task. We show that the visual-evoked potential (VEP) of the LFP in V4 is highly sensitive to color, whereas the VEP in prefrontal cortex predominantly depends on image structure. When examining the relationship between VEP and SUA, we found that stimulus sensitivity for SUA was well predicted by the VEP in PF cortex but not in V4. Our results first reveal a functional specialization in both areas at the level of the LFP and further suggest that the degree to which mesoscopic signals, such as the VEP, are representative of the underlying SUA neural processing may be brain region specific within the context of visual recognition. PMID:21752998

  17. Multichannel Seismic Imaging of the Rivera Plate Subduction at the Seismogenic Jalisco Block Area (Western Mexican Margin)

    Science.gov (United States)

    Bartolome, Rafael; Górriz, Estefanía; Dañobeitia, Juanjo; Cordoba, Diego; Martí, David; Cameselle, Alejandra L.; Núñez-Cornú, Francisco; Bandy, William L.; Mortera-Gutiérrez, Carlos A.; Nuñez, Diana; Castellón, Arturo; Alonso, Jose Luis

    2016-10-01

    During the TSUJAL marine geophysical survey, conducted in February and March 2014, Spanish, Mexican and British scientists and technicians explored the western margin of Mexico, considered one of the most active seismic zones in America. This work aims to characterize the internal structure of the subduction zone of the Rivera plate beneath the North American plate in the offshore part of the Jalisco Block, to link the geodynamic and the recent tectonic deformation occurring there with the possible generation of tsunamis and earthquakes. For this purpose, it has been carried out acquisition, processing and geological interpretation of a multichannel seismic reflection profile running perpendicular to the margin. Crustal images show an oceanic domain, dominated by subduction-accretion along the lower slope of the margin with a subparallel sediment thickness of up to 1.6 s two-way travel time (approx. 2 km) in the Middle American Trench. Further, from these data the region appears to be prone to giant earthquake production. The top of the oceanic crust (intraplate reflector) is very well imaged. It is almost continuous along the profile with a gentle dip (developed accretionary prism consisting of highly deformed sediments with prominent slumping towards the trench that may be the result of past tsunamis. Also, a bottom simulating reflector (BSR) is identified in the first half a second (twtt) of the section. High amplitude reflections at around 7-8 s twtt clearly image a discontinuous Moho, defining a very gentle dipping subduction plane.

  18. Flood-threat zoning map of the urban area of Chocó (Quibdó. A study based on interpreting radar, satellite and aerial photograph images

    Directory of Open Access Journals (Sweden)

    Zamir Maturana Córdoba

    2010-04-01

    Full Text Available A zoning map of areas which flood due to the Atrato River and its tributaries (the Cabí, Caraño and Yesca over-flowing in the urban area of Chocó (Quibdo was drawn up to be used by aid authorities and Quibdó city as a planning and control tool. This research relied on CIAF (Centro Interamericano de Fotointerpretación support and assessment. This entity is a subsidiary institution of the Instituto Geográfico Agustín Codazzi which provided their installations and the required geographical material. This research was initially based on interpreting radar (INTERA, satellite (LANDSAT and aerial photographic images; this was verified by field verification of the in-terpreted data. Other variables such as climatic, geological, temperature, topographic conditions, historic and hydrological series and facts regarding the region were studied as additional information required for drawing conclusions. Aerial photographs provided the most reliable images due to their scales, quantity and quality and the date of when they were taken. Radar images (INTERA were also important when visually analysing a sector’s topography as they were produced by an active microwave sensor (totally eliminating climatic obstacles. On the contrary, satellite images did not have great relevance due to the amount of clouds hampering any kind of analysis. Complementing these results, a calibration curve for analysing this section’s maximum flow values was based on historical series data regarding the Atrato River’s flows and maximum levels recorded at the Quibdo hydrographical station and the river-bed’s cross-section. Implications that the river would overflow or has over-flowed were statistically estimated on these results, thereby setting the limits (supported by cartographic data for the corresponding areas at risk of flooding. A map marking areas at risk of flooding in the urban zone of Quibdó was then designed and a document prepared concluding that

  19. Correlation between the Effects of Acupuncture at Taichong (LR3) and Functional Brain Areas: A Resting-State Functional Magnetic Resonance Imaging Study Using True versus Sham Acupuncture.

    Science.gov (United States)

    Wu, Chunxiao; Qu, Shanshan; Zhang, Jiping; Chen, Junqi; Zhang, Shaoqun; Li, Zhipeng; Chen, Jiarong; Ouyang, Huailiang; Huang, Yong; Tang, Chunzhi

    2014-01-01

    Functional magnetic resonance imaging (fMRI) has been shown to detect the specificity of acupuncture points, as proved by numerous studies. In this study, resting-state fMRI was used to observe brain areas activated by acupuncture at the Taichong (LR3) acupoint. A total of 15 healthy subjects received brain resting-state fMRI before acupuncture and after sham and true acupuncture, respectively, at LR3. Image data processing was performed using Data Processing Assistant for Resting-State fMRI and REST software. The combination of amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) was used to analyze the changes in brain function during sham and true acupuncture. Acupuncture at LR3 can specifically activate or deactivate brain areas related to vision, movement, sensation, emotion, and analgesia. The specific alterations in the anterior cingulate gyrus, thalamus, and cerebellar posterior lobe have a crucial effect and provide a valuable reference. Sham acupuncture has a certain effect on psychological processes and does not affect brain areas related to function. PMID:24963329

  20. Development of a Code to Analyze the Solar White-Light Images from the Kodaikanal Observatory: Detection of Sunspots, Computation of Heliographic Coordinates and Area

    Indian Academy of Sciences (India)

    Ragadeepika Pucha; K. M. Hiremath; Shashanka R. Gurumath

    2016-03-01

    Sunspots are the most conspicuous aspects of the Sun. They have a lower temperature, as compared to the surrounding photosphere; hence, sunspots appear as dark regions on a brighter background. Sunspots cyclically appear and disappear with a 11-year periodicity and are associated with a strong magnetic field $(\\sim 10^3$ G) structure. Sunspots consist of a dark umbra, surrounded by a lighter penumbra. Study of umbra–penumbra area ratio can be used to give a rough idea as to how the convective energy of the Sun is transported from the interior, as the sunspot’s thermal structure is related to this convective medium. An algorithm to extract sunspots from the white-light solar images obtained from the Kodaikanal Observatory is proposed. This algorithm computes the radius and center of the solar disk uniquely and removes the limb darkening from the image. It also separates the umbra and computes the position as well as the area of the sunspots. The estimated results are compared with the Debrecen photoheliographic results. It is shown that both area and position measurements are in quite good agreement.

  1. [Landscape pattern changes at village scale using high resolution satellite images: A case study in low-slope hilly area of Dali City, Northwestern Yunnan Province].

    Science.gov (United States)

    Zhao, Ming-yue; Peng, Jian; Liu, Yan-xu; Zhang, Tian

    2015-12-01

    Human activity is the main driving force of the change of land cover and landscape patterns. However, there are few studies focusing on the mechanism of human-induced change of land cover and landscape patterns at village scale. In this study, taking low-slope hilly area of Dali City, Northwestern Yunnan Province as a case study area, high resolution satellite images were introduced to find out the rules of land cover and landscape pattern changes, i.e. GeoEye-1 of 2009 and World- View-3 of 2014. The object-oriented and human-computer-interaction approaches were applied to interpret the images using ArcGIS 10.2 and ENVI 5.2. The results showed that, the main land cover types in the study area were forest land, paddy field and dry land in 2009, with forest, bulldozed unbuilt ground and paddy field in 2014, accounting for 82.8% and 70.9% of the total area, respectively. The land cover transition showed that, during 2009-2014, the main land cover change flows were from forest land, paddy field and dry land, to bulldozed unbuilt ground and construction land. Furthermore, the area of bulldozed but unbuilt land had increased to be 531.57 hm² in 2014, which mainly came from forest land (42.8%), dry land (21.7%), and paddy field (14.2%). Landscape pattern change was characterized as the increase of patch quantity and density, the decrease of mean patch size, the complication of patch shape, the fragmentation of landscape patches, and the diversification of landscape patterns.

  2. Full-Waveform, Wide-Swath Lidar Imaging of Forested and Urban Areas in Leaf-On Conditions: Development, Results and Future Direction

    Science.gov (United States)

    Blair, James B.; Hofton, M.; Rabine, David; Welch, Wayne; Ramos, Luis; Padden, Phillip

    2003-01-01

    Full-Waveform lidar measurements provide unprecedented views of the vertical and horizontal structure of vegetation and the topography of the Earth s surface. Utilizing a high signal-to-noise ratio lidar system, larger than typical laser footprints (10-20 m), and the recorded time history of interaction between a short-duration (approx. 10 ns) pulse of laser light and the surface of the Earth, full-waveform lidar is able to simultaneously image sub-canopy topography as well as the vertical structure of any overlying vegetation. These data reveal the true 3-D vegetation structure in leaf-on conditions enabling important biophysical parameters such as above-ground biomass to be estimated with unprecedented accuracy. An airborne lidar mission was conducted July-August 2003 in support of the North America Carbon Program. NASA s Laser Vegetation Imaging Sensor (LVIS) was used to image approximately 2,000 km$^2$ in Maine, New Hampshire, Massachusetts and Maryland. Areas with available ground and other data were included (e.g., experimental forests, FLUXNET sites) in order to facilitate as many bio- and geophysical investigations as possible. Data collected included ground elevation and canopy height measurements for each laser footprint, as well as the vertical distribution of intercepted surfaces. Data will be publicly distributed within 6- 12 months of collection. Further details of the mission, including the lidar system technology, the locations of the mapped areas, and examples of the numerous data products that can be derived from the return waveform data products will be presented. Future applications including detection of ground and vegetation canopy changes and a spaceborne implementation of wide-swath, full-waveform imaging lidar will also be discussed.

  3. HyMaP: A hybrid magnitude-phase approach to unsupervised segmentation of tumor areas in breast cancer histology images

    Directory of Open Access Journals (Sweden)

    Adnan M Khan

    2013-01-01

    Full Text Available Background: Segmentation of areas containing tumor cells in standard H&E histopathology images of breast (and several other tissues is a key task for computer-assisted assessment and grading of histopathology slides. Good segmentation of tumor regions is also vital for automated scoring of immunohistochemical stained slides to restrict the scoring or analysis to areas containing tumor cells only and avoid potentially misleading results from analysis of stromal regions. Furthermore, detection of mitotic cells is critical for calculating key measures such as mitotic index; a key criteria for grading several types of cancers including breast cancer. We show that tumor segmentation can allow detection and quantification of mitotic cells from the standard H&E slides with a high degree of accuracy without need for special stains, in turn making the whole process more cost-effective. Method: Based on the tissue morphology, breast histology image contents can be divided into four regions: Tumor, Hypocellular Stroma (HypoCS, Hypercellular Stroma (HyperCS, and tissue fat (Background. Background is removed during the preprocessing stage on the basis of color thresholding, while HypoCS and HyperCS regions are segmented by calculating features using magnitude and phase spectra in the frequency domain, respectively, and performing unsupervised segmentation on these features. Results: All images in the database were hand segmented by two expert pathologists. The algorithms considered here are evaluated on three pixel-wise accuracy measures: precision, recall, and F1-Score. The segmentation results obtained by combining HypoCS and HyperCS yield high F1-Score of 0.86 and 0.89 with re-spect to the ground truth. Conclusions: In this paper, we show that segmentation of breast histopathology image into hypocellular stroma and hypercellular stroma can be achieved using magnitude and phase spectra in the frequency domain. The segmentation leads to demarcation of tumor

  4. Relationship of the area measurement of the large endolymphatic duct and sac syndrome as well as the clinical symptoms with CT and MR imaging results

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Sang; Hong, Hyun Sook; Lee, Jong Sea; Kim, Dae Ho; Lee, Hae Kyung; Yi, Beom Ha; Cha, Jang Gyu; Park, Seong Jin; Kim, Shi Chan [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of)

    2008-08-15

    To evaluate the CT and MRI findings of the large endolymphatic duct or sac syndrome (LEDS) and its associated anomalies, with clinical features. We retrospectively reviewed the MR and CT images of 52 ears obtained from 26 patients with LEDS. We reviewed the clinical findings, audiology testing, and treatment results. The degree of hearing loss was classified from normal to profound, based on pure tone audiometry. The largest areas were measured at each endolymphatic duct and analyzed to determine whether a correlation exists with the degree of hearing loss. We also analyzed the differences in measurements between CT and MRI findings. All 26 patients had some degree of sensorineural hearing loss, which resulted in 18 ears to undergo a cochlear implantation. One patient was diagnosed with Cornelia de Lange syndrome. Five patients had a sudden hearing loss onset. Ten ears had incomplete cochlear partitions, whereas 28 ears had enlarged vestibules. All patients had severe to profound hearing loss. We found no statistical correlation between the size of the largest area of the endolymphatic duct and the degree of hearing loss. The mean area of the endolymphatic ducts, as per an MRI examination, revealed slightly greater areas than the CT findings, although the differences were not significant. Enlarged vestibules and incomplete partitions of the cochlea were common anomalies associated with LEDS. We found no statistical correlation between the largest area of the endolymphatic duct or sac with the degree of hearing loss.

  5. Relationship of the area measurement of the large endolymphatic duct and sac syndrome as well as the clinical symptoms with CT and MR imaging results

    International Nuclear Information System (INIS)

    To evaluate the CT and MRI findings of the large endolymphatic duct or sac syndrome (LEDS) and its associated anomalies, with clinical features. We retrospectively reviewed the MR and CT images of 52 ears obtained from 26 patients with LEDS. We reviewed the clinical findings, audiology testing, and treatment results. The degree of hearing loss was classified from normal to profound, based on pure tone audiometry. The largest areas were measured at each endolymphatic duct and analyzed to determine whether a correlation exists with the degree of hearing loss. We also analyzed the differences in measurements between CT and MRI findings. All 26 patients had some degree of sensorineural hearing loss, which resulted in 18 ears to undergo a cochlear implantation. One patient was diagnosed with Cornelia de Lange syndrome. Five patients had a sudden hearing loss onset. Ten ears had incomplete cochlear partitions, whereas 28 ears had enlarged vestibules. All patients had severe to profound hearing loss. We found no statistical correlation between the size of the largest area of the endolymphatic duct and the degree of hearing loss. The mean area of the endolymphatic ducts, as per an MRI examination, revealed slightly greater areas than the CT findings, although the differences were not significant. Enlarged vestibules and incomplete partitions of the cochlea were common anomalies associated with LEDS. We found no statistical correlation between the largest area of the endolymphatic duct or sac with the degree of hearing loss

  6. Multichannel Seismic Imaging of the Rivera Plate Subduction at the Seismogenic Jalisco Block Area (Western Mexican Margin)

    Science.gov (United States)

    Bartolome, Rafael; Górriz, Estefanía; Dañobeitia, Juanjo; Cordoba, Diego; Martí, David; Cameselle, Alejandra L.; Núñez-Cornú, Francisco; Bandy, William L.; Mortera-Gutiérrez, Carlos A.; Nuñez, Diana; Castellón, Arturo; Alonso, Jose Luis

    2016-06-01

    During the TSUJAL marine geophysical survey, conducted in February and March 2014, Spanish, Mexican and British scientists and technicians explored the western margin of Mexico, considered one of the most active seismic zones in America. This work aims to characterize the internal structure of the subduction zone of the Rivera plate beneath the North American plate in the offshore part of the Jalisco Block, to link the geodynamic and the recent tectonic deformation occurring there with the possible generation of tsunamis and earthquakes. For this purpose, it has been carried out acquisition, processing and geological interpretation of a multichannel seismic reflection profile running perpendicular to the margin. Crustal images show an oceanic domain, dominated by subduction-accretion along the lower slope of the margin with a subparallel sediment thickness of up to 1.6 s two-way travel time (approx. 2 km) in the Middle American Trench. Further, from these data the region appears to be prone to giant earthquake production. The top of the oceanic crust (intraplate reflector) is very well imaged. It is almost continuous along the profile with a gentle dip (<10°); however, it is disrupted by normal faulting resulting from the bending of the plate during subduction. The continental crust presents a well-developed accretionary prism consisting of highly deformed sediments with prominent slumping towards the trench that may be the result of past tsunamis. Also, a bottom simulating reflector (BSR) is identified in the first half a second (twtt) of the section. High amplitude reflections at around 7-8 s twtt clearly image a discontinuous Moho, defining a very gentle dipping subduction plane.

  7. Status of the development of large area photon detectors based on THGEMs and hybrid MPGD architectures for Cherenkov imaging applications

    Science.gov (United States)

    Alexeev, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Büchele, M.; Chiosso, M.; Ciliberti, P.; Torre, S. Dalla; Dasgupta, S.; Denisov, O.; Duic, V.; Finger, M.; Finger, M.; Fischer, H.; Giorgi, M.; Gobbo, B.; Gregori, M.; Herrmann, F.; Königsmann, K.; Levorato, S.; Maggiora, A.; Martin, A.; Menon, G.; Steiger, K.; Novy, J.; Panzieri, D.; Pereira, F. A.; Santos, C. A.; Sbrizzai, G.; Schiavon, P.; Schopferer, S.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Takekawa, S.; Tessarotto, F.; Veloso, J. F. C. A.; Makke, N.

    2016-07-01

    We report about the development status of large area gaseous single photon detectors based on a novel hybrid concept for RICH applications. The hybrid concept combines Thick Gaseous Electron Multipliers (THGEMs) coupled to CsI, working as a photon sensitive pre-amplification stage, and Micromegas, as a multiplication stage. The most recent achievements within the research and development programme consist in the assembly and study of 300 × 300mm2 hybrid photon detectors, the optimization of front-end electronics, and engineering towards large area detectors. Hybrid detectors with an active area of 300 × 300mm2 have been successfully operated in laboratory conditions and at a CERN PS T10 test beam, achieving effective gains in the order of 105 and good time resolution (σ = 7 ns); APV25 front-end chips have been coupled to the detector resulting in noise levels lower than 1000 electrons; the production and characterization of 300 × 600mm2 THGEMs is ongoing. A set of hybrid detectors with 600 × 600mm2 active area is envisaged to upgrade COMPASS RICH-1 at CERN in 2016.

  8. Utilization of Remote Sensing Image and GIS to Mapping Vulnerable Areas of DHF: A Case Study of Pangandaran, West Java

    Directory of Open Access Journals (Sweden)

    Andri Ruliansyah

    2011-12-01

    Full Text Available Dengue hemorrhagic fever (DHF are acute febrile diseases, found in tropical and sub tropical regions, caused by dengue virus of the genus Flavivirus, family Flaviviridae. Sub district Pangandaran is an area that is quite a sharp increase in his case. Ranging from no cases in the period 1998-2002 increased 1 case in 2003, 4 cases in 2004, 22 cases in 2005, 35 cases in 2006, 10 cases in 2007, 12 cases in 2008, 14 cases in 2009 and 13 cases in 2010. The purpose of th is study was to determine the ability of remote sensing imagery and G1S in the determination of physical environmental factors for the mapping of areas prone to den­gue fever, dengue fever spreads are based on the distribution of cas es, places, and times from 2005 through to 2010 and determine the level of vulnerability to dengue based on envi­ronmental variables and incidence of DHF. This study is an observational research with cross sectional analysis approach. The results showed that the integration of remote sensing imagery and G1S to analyze the physical environmental risk factors associated with the spread of dengue include: land use, altitude, ra infa ll, area mosquito and fly larvae density area. Distribution pattern of dengue in the district during the last 6 years Pangandaran con­centrated in the southern region of Pangandaran sub-district, the Pangandaran village, Pananjung and Babakan. Distribution of cases based on patient characteristics dominated in the groups of children and adolescents, while based on gender, women are more exposed cases compared to male. 1ncidence of dengue fever occur each after a decline in rainfall from the previous month and decreased at the back there was an increase of ra infa ll. Zoning level of vulnerability to dengue were in the southern district of Pangandaran, the village of Pangandaran, Babakan, Pananjung, Wonoharjo and Most Sukahurip. Broad zone of high vulnerability areas in the Pangandaran sub-district DHF is 22.76 km2 (30.07%, wide

  9. The use of the lumbosacral enlargement as an intrinsic imaging biomarker: feasibility of grey matter and white matter cross-sectional area measurements using MRI at 3T.

    Directory of Open Access Journals (Sweden)

    Marios C Yiannakas

    Full Text Available Histopathological studies have demonstrated the involvement of spinal cord grey matter (GM and white matter (WM in several diseases and recent research has suggested the use of magnetic resonance imaging (MRI as a promising tool for in vivo assessment of the upper spinal cord. However, many neurological conditions would benefit from quantitative assessment of tissue integrity at different levels and relatively little work has been done, mainly due to technical challenges associated with imaging the lower spinal cord. In this study, the value of the lumbosacral enlargement (LSE as an intrinsic imaging biomarker was determined by exploring the feasibility of obtaining within it reliable GM and WM cross-sectional area (CSA measurements by means of a commercially available MRI system at 3 tesla (T. 10 healthy volunteers (mean age 27.5 years, 6 female gave written informed consent and high resolution images of the LSE were acquired and analysed using an optimised MRI acquisition and analysis protocol. GM and WM mean CSA measurements were obtained from a 15 mm section at the level of the LSE and the reproducibility of the measurements was determined by means of scan-rescan, intra- and inter-observer assessments. Mean (±SD LSE cross-sectional area (LSE-CSA was 62.3 (±4.1 mm2 and mean (±SD LSE grey matter cross-sectional area (LSE-GM-CSA was 19.8 (±3.3 mm2. The mean scan-rescan, intra- and inter-observer % coefficient of variation (COV for measuring the LSE-CSA were 2%, 2% and 2.5%, respectively and for measuring the LSE-GM-CSA were 7.8%, 8% and 8.6%, respectively. This study has shown that the LSE can be used reliably as an intrinsic imaging biomarker. The method presented here can be potentially extended to study the LSE in the diseased state and could provide a solid foundation for subsequent multi-parametric MRI investigations.

  10. Persistent photoeffects in p-i-n GaAs/AlGaAs heterostructures with double quantum wells

    DEFF Research Database (Denmark)

    Dorozhkin, S.I.; Timofeev, V.B.; Hvam, Jørn Märcher

    2001-01-01

    similar to 2 K) and the dc voltage applied to the structure. A memory effect was detected; this effect manifested itself in the long lifetime of anomalies observed after the illumination had been turned off. Self-consistent calculations of distributions of charge and electric field were performed...... for the structures that contained a donor impurity in AlGaAs layers; this impurity is responsible for origination of DX centers that give rise to persistent photoconductivity. It is demonstrated that abrupt changes in capacitance can occur in such a structure, and the values of the parameters required...... for origination of these jumps are determined....

  11. Visible Light Sensitization of Titanium Dioxide with Self-Organized Porphyrins : Organic P-I-N Solar Cells

    NARCIS (Netherlands)

    Wienke, J.; Schaafsma, T.J.; Goossens, A.

    1999-01-01

    Free base 5,10,15,20-tetrakis(4-n-octylphenyl) porphyrin (H2TOPP) belongs to a class of self-organizing porphyrins. Since its LUMO lies above the conduction band of titanium dioxide (TiO2) and its visible light absorption is very strong, sensitization of TiO2 with H2TOPP thin films is possible. Afte

  12. Portable gamma- and X-ray analyzers based on CdTe p-i-n detectors

    CERN Document Server

    Khusainov, A K; Bahlanov, S V; Derbin, A V; Ivanov, V V; Lysenko, V V; Morozov, F; Mouratov, V G; Muratova, V N; Petukhov, Y A; Pirogov, A M; Polytsia, O P; Saveliev, V D; Solovei, V A; Yegorov, K A; Zhucov, M P

    1999-01-01

    Several portable instruments are designed using previously reported CdTe detector technology. These can be divided into three groups according to their energy ranges: (1) 3-30 keV XRF analyzers, (2) 5-120 keV wide range XRF analyzers and (3) gamma-ray spectrometers for operation up to 1500 keV. These instruments are used to inspect several hundreds of samples in situ during a working day in applications such as a metal alloy verification at customs control. Heavy metals are identified through a 3-100 mm thick package with these instruments. Surface contamination by heavy metals (for example toxins such as Hg, Th and Pb in housing environmental control), the determination of Pb concentration in gasoline, geophysical control in mining, or nuclear material control are other applications. The weight of these XRF probes is about 1 kg and two electronic designs are used: one with embedded computer and another based on a standard portable PC. The instruments have good precision and high productivity for measurements...

  13. Quick geometric processing of large area unmanned aerial vehicle images%大区域无人机影像数据的快速几何处理

    Institute of Scientific and Technical Information of China (English)

    孙磊; 郭海涛; 李传广; 李海滨; 姜春雪

    2016-01-01

    无人机遥感影像快速几何处理被广泛应用于灾害应急监测与评估、军事侦察等领域。针对目前多数商业软件所依赖的硬件平台成本昂贵、软件开发过程复杂等问题,面向通用硬件平台,提出一种大区域无人机影像数据的快速几何处理方法。对制约处理效率的各关键算法进行优化和改造,实现大区域无人机影像数据的快速几何处理;在影像连接点匹配、正射纠正和影像镶嵌的处理过程中,均应用基于多核CPU并行处理技术,提高整体处理效率。多组无人机影像数据处理试验表明,该方法能够大幅提高处理效率,对硬件平台要求低,具有推广应用价值。%Unmanned aerial vehicle images (UAV ) rapid geometric processing is widely used in disaster emergency monitoring and evaluation ,military reconnaissance ,and the like .The hardware platform on which most present business softwares depend is expensive ,and the software development process is complex .A quick geometric processing method of large area UAV images for general hardware platform is proposed .The key algorithms which restrict the efficiency are optimized and modified and the rapid geometric processing of large area UAV images is implemented .In the process of join points image matching ,ortho‐rectification and image mosaic ,the multi‐core CPU parallel processing technology is applied and the efficiency of the whole process is improved .Multiple sets of UAV image data processing results show the method has a great potential in the field of application for its improved efficiency and low requirements for hardware platform .

  14. Monitoring Spatio-Temporal Distribution of Rice Planting Area in the Yangtze River Delta Region Using MODIS Images

    OpenAIRE

    Jingjing Shi; Jingfeng Huang

    2015-01-01

    A large-area map of the spatial distribution of rice is important for grain yield estimations, water management and an understanding of the biogeochemical cycling of carbon and nitrogen. In this paper, we developed the Normalized Weighted Difference Water Index (NWDWI) for identifying the unique characteristics of rice during the flooding and transplanting period. With the aid of the ASTER Global Digital Elevation Model and the phenological data observed at agrometeorological stations, the sp...

  15. RESEARCHES ON THE LAND-USE CHANGE DETECTION OF MINE AREA BASED ON TM/ETM IMAGES

    OpenAIRE

    Qin, Y.; H. Liling; Min, Y; Yi, L.

    2013-01-01

    With the economic development and population growth, land use status is changing rapidly in Chinese urban. Since the remote sensing technology can analyze and detect the land use information quickly and accurately, it has been widely applied to obtain the land use/land cover change (LUCC) information today. The land surface destroy occurred in mineral resources exploration will result in a lot of environmental problems in coal mine areas. But there are few research in small and me...

  16. Evaluation of a WorldView-2 image for soil salinity monitoring in a moderately affected irrigated area

    Science.gov (United States)

    Vermeulen, Divan; van Niekerk, Adriaan

    2016-04-01

    Conventional methods for monitoring salt accumulation within irrigation schemes involve regular field visits to collect soil samples for laboratory analysis. Remote sensing has been proposed as a less time-consuming, more cost-effective alternative as it provides imagery covering large areas throughout the year. This study evaluated the efficacy of very high resolution (VHR) WorldView-2 imagery to map areas affected by salt accumulation. Classifications based on thresholds obtained from Jeffries-Matusita distance, regression modeling, classification and regression trees, as well as supervised classification approaches, were evaluated for discriminating between salt-affected and unaffected soils in Vaalharts, South Africa. The WorldView-2 bands were supplemented with salinity indices (SIs), principal components, and texture measures to increase the number of predictive variables. In situ soil samples were used for model development, classifier training, and accuracy assessment. The results showed that a simple threshold implemented on a normalized difference SI was the most successful in separating classes, with an overall accuracy of 80%. The findings suggest that VHR satellite imagery holds much potential for monitoring salt accumulation, but more research is needed to investigate why the classification results tend to overestimate salt-affected areas. More work is also needed to evaluate the transferability of the techniques to other irrigation schemes.

  17. The 1946 Unimak Tsunami Earthquake Area: revised tectonic structure in reprocessed seismic images and a suspect near field tsunami source

    Science.gov (United States)

    Miller, John J.; von Huene, Roland; Ryan, Holly F.

    2014-01-01

    In 1946 at Unimak Pass, Alaska, a tsunami destroyed the lighthouse at Scotch Cap, Unimak Island, took 159 lives on the Hawaiian Islands, damaged island coastal facilities across the south Pacific, and destroyed a hut in Antarctica. The tsunami magnitude of 9.3 is comparable to the magnitude 9.1 tsunami that devastated the Tohoku coast of Japan in 2011. Both causative earthquake epicenters occurred in shallow reaches of the subduction zone. Contractile tectonism along the Alaska margin presumably generated the far-field tsunami by producing a seafloor elevation change. However, the Scotch Cap lighthouse was destroyed by a near-field tsunami that was probably generated by a coeval large undersea landslide, yet bathymetric surveys showed no fresh large landslide scar. We investigated this problem by reprocessing five seismic lines, presented here as high-resolution graphic images, both uninterpreted and interpreted, and available for the reader to download. In addition, the processed seismic data for each line are available for download as seismic industry-standard SEG-Y files. One line, processed through prestack depth migration, crosses a 10 × 15 kilometer and 800-meter-high hill presumed previously to be basement, but that instead is composed of stratified rock superimposed on the slope sediment. This image and multibeam bathymetry illustrate a slide block that could have sourced the 1946 near-field tsunami because it is positioned within a distance determined by the time between earthquake shaking and the tsunami arrival at Scotch Cap and is consistent with the local extent of high runup of 42 meters along the adjacent Alaskan coast. The Unimak/Scotch Cap margin is structurally similar to the 2011 Tohoku tsunamigenic margin where a large landslide at the trench, coeval with the Tohoku earthquake, has been documented. Further study can improve our understanding of tsunami sources along Alaska’s erosional margins.

  18. Determination of Landslide and Driftwood Potentials by Fixed-wing UAV-Borne RGB and NIR images: A Case Study of Shenmu Area in Taiwan

    Science.gov (United States)

    Chen, Su-Chin; Hsiao, Yu-Shen; Chung, Ta-Hsien

    2015-04-01

    This study is aimed at determining the landslide and driftwood potentials at Shenmu area in Taiwan by Unmanned Aerial Vehicle (UAV). High-resolution orthomosaics and digital surface models (DSMs) are both obtained from several UAV practical surveys by using a red-green-blue(RGB) camera and a near-infrared(NIR) one, respectively. Couples of artificial aerial survey targets are used for ground control in photogrammtry. The algorithm for this study is based on Logistic regression. 8 main factors, which are elevations, terrain slopes, terrain aspects, terrain reliefs, terrain roughness, distances to roads, distances to rivers, land utilizations, are taken into consideration in our Logistic regression model. The related results from UAV are compared with those from traditional photogrammetry. Overall, the study is focusing on monitoring the distribution of the areas with high-risk landslide and driftwood potentials in Shenmu area by Fixed-wing UAV-Borne RGB and NIR images. We also further analyze the relationship between forests, landslides, disaster potentials and upper river areas.

  19. Assessing differences in phenology patterns between burned and non burned areas using MODIS and Landsat time series satellite images. A case study in Peloponnisos (Greece) and Sardinia (Italy)

    Science.gov (United States)

    Koutsias, Nikos; Bajocco, Sofia

    2016-04-01

    Vegetation phenology is an important element of vegetation characteristics that can be useful in vegetation monitoring especially when satellite remote sensing observations are used. In that sense temporal profiles extracted from spectral signal of time series satellite images can be used to characterize vegetation phenology and thus can be helpful for assessing, for example, phenology patterns between burned and non-burned areas. The aim of this study is to define phenological patterns for the fire ignition points in two Mediterranean study areas located in Italy (Sardinia) and Greece (Peloponnisos) and compare them with control points created after random sampling techniques restricted to certain buffer zones. Remotely sensed data from MODIS (2000-2015) and LANDSAT (1984-2015) satellites were acquired and processed to extract the temporal profiles of the spectral signal of fire ignition points and of control points. Apart of the use of the original spectral data, we used vegetation indices commonly found in vegetation studies as well as in burned area mapping studies. Different metrics linked to key phenological events have been derived and used to assess vegetation phenology in the fire-affected areas.

  20. Imaging of olfactory bulb and gray matter volumes in brain areas associated with olfactory function in patients with Parkinson's disease and multiple system atrophy

    International Nuclear Information System (INIS)

    We explored if magnetic resonance imaging sequences might aid in the clinical differential diagnosis of idiopathic Parkinson's disease (IPD) and multiple system atrophy (MSA). We measured the volumes of the olfactory bulb, the olfactory tract, and olfaction-associated cortical gray matter in 20 IPD patients, 14 MSA patients, and 12 normal subjects, using high-resolution magnetic resonance imaging sequences in combination with voxel-based statistical analysis. We found that, compared to normal subjects and MSA patients, the volumes of the olfactory bulb and tract were significantly reduced in IPD patients. The gray matter volume of IPD patients decreased in the following order: the olfactory area to the right of the piriform cortex, the right amygdala, the left entorhinal cortex, and the left occipital lobe. Further, the total olfactory bulb volume of IPD patients was associated with the duration of disease. The entorhinal cortical gray matter volume was negatively associated with the UPDRS III score. Conclusion: Structural volumes measured by high-resolution magnetic resonance imaging may potentially be used for differential diagnosis of IPD from MSA

  1. Imaging of olfactory bulb and gray matter volumes in brain areas associated with olfactory function in patients with Parkinson's disease and multiple system atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shun, E-mail: shchen_2013@163.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China); Tan, Hong-yu, E-mail: honhyutan@21cn.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China); Wu, Zhuo-hua, E-mail: zhh88@126.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China); Sun, Chong-peng, E-mail: Suncp2002@gmail.com [Imaging Center, The First Affiliated Hospital of Guangzhou Medical College (China); He, Jian-xun, E-mail: xundog@163.com [Imaging Center, The First Affiliated Hospital of Guangzhou Medical College (China); Li, Xin-chun, E-mail: xinchunli@163.com [Imaging Center, The First Affiliated Hospital of Guangzhou Medical College (China); Shao, Ming, E-mail: yimshao@126.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China)

    2014-03-15

    We explored if magnetic resonance imaging sequences might aid in the clinical differential diagnosis of idiopathic Parkinson's disease (IPD) and multiple system atrophy (MSA). We measured the volumes of the olfactory bulb, the olfactory tract, and olfaction-associated cortical gray matter in 20 IPD patients, 14 MSA patients, and 12 normal subjects, using high-resolution magnetic resonance imaging sequences in combination with voxel-based statistical analysis. We found that, compared to normal subjects and MSA patients, the volumes of the olfactory bulb and tract were significantly reduced in IPD patients. The gray matter volume of IPD patients decreased in the following order: the olfactory area to the right of the piriform cortex, the right amygdala, the left entorhinal cortex, and the left occipital lobe. Further, the total olfactory bulb volume of IPD patients was associated with the duration of disease. The entorhinal cortical gray matter volume was negatively associated with the UPDRS III score. Conclusion: Structural volumes measured by high-resolution magnetic resonance imaging may potentially be used for differential diagnosis of IPD from MSA.

  2. Satellite images as primers to target priority areas for field surveys of indicators of ecological sustainability in tropical forests

    Science.gov (United States)

    Aguilar-Amuchastegui, Naikoa

    Sustainable management of tropical forests has been identified as one of the main objectives for global conservation of carbon stocks. In order to achieve this, managers need tools to establish whether or not their management practices are sustainable. Several tool development initiatives have undertaken the creation of sets of criteria and indicators to aid managers to target, if not achieve, sustainability. The question of how to assess these indicators remains to be answered from an operational viewpoint, where logistical constraints become critical and priorization becomes necessary. The present dissertation sought to determine whether satellite imagery can be used, in conjunction with standard forest management data, to identify priority areas for field surveys of indicators of ecological sustainability of managed tropical forests. It presents a novel approach to the assessment of CIFOR indicator I.2.1.2: "The change in diversity of habitats as a result of human interventions is maintained within critical limits as defined by natural variation and/or regional conservation objectives" by means of semivariography of remote sensing data. It shows the Wide Dynamic Range Vegetation Index (WDRVI) is a good alternative for the detection and quantification of tropical forests structural heterogeneity and its dynamic change. The differences observed between forest management units and natural areas forest structural heterogeneity were used to identify priority areas for field survey of ecological sustainability indicators and evaluate how these priorities were reflected in dung beetles community structure and composition. The link between forest structural heterogeneity dynamic change, forest logging intensity and dung beetle community structure and composition is established. A logging intensity threshold of 4 trees per hectare is identified as the limit between significant or not significant differences in forest structure dynamic changes and dung beetles community

  3. Multiple Suppression and Imaging of Marine Seismic Data from The Shallow Water Area in Southern East China Sea Shelf Basin

    Science.gov (United States)

    Shi, J.; Luan, X.; Yang, C.

    2015-12-01

    Neither surface-related multiple elimination(SRME) nor predictive de-convolution method is effective to suppress the multiple of marine seismic data from the shallow water area. The former method needs the accurate reflection of seafloor, which is mixed with the direct wave in the near offset range. The other one could probably lose the primary wave when applied to the shallow water seismic data. We introduced the new method: deterministic water-layer de-multiple method (DWD) which is capable for the poor extrapolate result of near-offset traces. Firstly, the data shifts as downward continuation in tau-p domain with a water-layer period and the multiple model will be obtained. Then, the original seismic subtracts adaptively with the multiple model. Finally, we would get the de-multiple data after inverse tau-p transform. Marine seismic real data is from southern part of East China Sea Shelf Basin. This area has become the potential target for marine hydrocarbon exploration, it is located in the junction of the Eurasian plate pacific plate and Indian plate. Because the average water depth is less than 100 meters, seismic data contains abundant of multiple, especially the surface-related multiple. As a result it is difficult to distinguish the strata structure clearly. We used DWD approach to remove the water-layer multiple, cut off the seafloor reflection events and then suppressed the residual surface-related multiple by the traditional SRME. At last , the radon transform was applied to eliminate the multiple with long period . With these steps, we suppressed the multiple of marine seismic data from this area effectively. After multiple is removed , we acquired more accurate velocity to build the velocity model of migration. With the pre-stack migration technique, reflections from each geological period are shown clearly in the seismic section. This work was supported by the National Science Foundation of China(grant no. 41476053).

  4. An easy to use ArcMap based texture analysis program for extraction of flooded areas from TerraSAR-X satellite image

    Science.gov (United States)

    Pradhan, Biswajeet; Hagemann, Ulrike; Shafapour Tehrany, Mahyat; Prechtel, Nikolas

    2014-02-01

    Extraction of the flooded areas from synthetic aperture radar (SAR) and especially TerraSAR-X data is one of the most challenging tasks in the flood management and planning. SAR data due to its high spatial resolution and its capability of all weather conditions makes a proper choice for tropical countries. Texture is considered as an effective factor in distinguishing the classes especially in SAR imagery which records the backscatters that carry information of kind, direction, heterogeneity and relationship of the features. This paper put forward a computer program for texture analysis for high resolution radar data. Texture analysis program is introduced and discussed using the gray-level co-occurrence matrix (GLCM). To demonstrate the ability and correctness of this program, a test subset of TerraSAR-X imagery from Terengganu area, Malaysia was analyzed and pixel-based and object-based classification were attempted. The thematic maps derived by pixel-based method could not achieve acceptable visual interpretation and for that reason no accuracy assessment was performed on them. The overall accuracy achieved by object-based method was 83.63% with kappa coefficient of 0.8. Results on image texture classification showed that the proposed program is capable for texture analysis in TerraSAR-X image and the obtained textural analysis resulted in high classification accuracy. The proposed texture analysis program can be used in many applications such as land use/cover (LULC) mapping, hazard studies and many other applications.

  5. Coherent Photon Scattering and Direct Imaging of the Iso-frequency Contours in Large-area Photonic Crystal Slabs

    CERN Document Server

    Regan, Emma C; Zhen, Bo; Kaminer, Ido; Hsu, Chia Wei; Shen, Yichen; Joannopoulos, John D; Soljacic, Marin

    2015-01-01

    While the absorption of light can be enhanced using optical resonances in a photonic crystal slab, the characteristics of resonance-enhanced scattering are much less studied. Here, we present an analytical model of resonance-enhanced photon scattering from generic fabrication errors and surface roughness, which agrees well with our experimental results. This phenomenon provides a new method to measure the photonic band structure and to directly map the iso-frequency contours of large-area photonic crystal slabs. Additionally, the iso-frequency contours provide information about the characteristics of the disorder and serve as a feedback tool to improve fabrication processes.

  6. Utilization of Remote Sensing Image and GIS to Mapping Vulnerable Areas of DHF: A Case Study of Pangandaran, West Java)

    OpenAIRE

    Andri Ruliansyah; Totok Gunawan; Sugeng Juwono M

    2011-01-01

    Dengue hemorrhagic fever (DHF) are acute febrile diseases, found in tropical and sub tropical regions, caused by dengue virus of the genus Flavivirus, family Flaviviridae. Sub district Pangandaran is an area that is quite a sharp increase in his case. Ranging from no cases in the period 1998-2002 increased 1 case in 2003, 4 cases in 2004, 22 cases in 2005, 35 cases in 2006, 10 cases in 2007, 12 cases in 2008, 14 cases in 2009 and 13 cases in 2010. The purpose of th is study was to determine t...

  7. Methods and measurement variance for field estimations of coral colony planar area using underwater photographs and semi-automated image segmentation.

    Science.gov (United States)

    Neal, Benjamin P; Lin, Tsung-Han; Winter, Rivah N; Treibitz, Tali; Beijbom, Oscar; Kriegman, David; Kline, David I; Greg Mitchell, B

    2015-08-01

    Size and growth rates for individual colonies are some of the most essential descriptive parameters for understanding coral communities, which are currently experiencing worldwide declines in health and extent. Accurately measuring coral colony size and changes over multiple years can reveal demographic, growth, or mortality patterns often not apparent from short-term observations and can expose environmental stress responses that may take years to manifest. Describing community size structure can reveal population dynamics patterns, such as periods of failed recruitment or patterns of colony fission, which have implications for the future sustainability of these ecosystems. However, rapidly and non-invasively measuring coral colony sizes in situ remains a difficult task, as three-dimensional underwater digital reconstruction methods are currently not practical for large numbers of colonies. Two-dimensional (2D) planar area measurements from projection of underwater photographs are a practical size proxy, although this method presents operational difficulties in obtaining well-controlled photographs in the highly rugose environment of the coral reef, and requires extensive time for image processing. Here, we present and test the measurement variance for a method of making rapid planar area estimates of small to medium-sized coral colonies using a lightweight monopod image-framing system and a custom semi-automated image segmentation analysis program. This method demonstrated a coefficient of variation of 2.26% for repeated measurements in realistic ocean conditions, a level of error appropriate for rapid, inexpensive field studies of coral size structure, inferring change in colony size over time, or measuring bleaching or disease extent of large numbers of individual colonies. PMID:26156316

  8. Multi-institutional Quantitative Evaluation and Clinical Validation of Smart Probabilistic Image Contouring Engine (SPICE) Autosegmentation of Target Structures and Normal Tissues on Computer Tomography Images in the Head and Neck, Thorax, Liver, and Male Pelvis Areas

    DEFF Research Database (Denmark)

    Zhu, Mingyao; Bzdusek, Karl; Brink, Carsten;

    2013-01-01

    Clinical validation and quantitative evaluation of computed tomography (CT) image autosegmentation using Smart Probabilistic Image Contouring Engine (SPICE).......Clinical validation and quantitative evaluation of computed tomography (CT) image autosegmentation using Smart Probabilistic Image Contouring Engine (SPICE)....

  9. Evaluation of the traffic parameters in a metropolitan area by fusing visual perceptions and CNN processing of webcam images.

    Science.gov (United States)

    Faro, Alberto; Giordano, Daniela; Spampinato, Concetto

    2008-06-01

    This paper proposes a traffic monitoring architecture based on a high-speed communication network whose nodes are equipped with fuzzy processors and cellular neural network (CNN) embedded systems. It implements a real-time mobility information system where visual human perceptions sent by people working on the territory and video-sequences of traffic taken from webcams are jointly processed to evaluate the fundamental traffic parameters for every street of a metropolitan area. This paper presents the whole methodology for data collection and analysis and compares the accuracy and the processing time of the proposed soft computing techniques with other existing algorithms. Moreover, this paper discusses when and why it is recommended to fuse the visual perceptions of the traffic with the automated measurements taken from the webcams to compute the maximum traveling time that is likely needed to reach any destination in the traffic network. PMID:18541508

  10. Imaging sciences workshop

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1994-11-15

    This workshop on the Imaging Sciences sponsored by Lawrence Livermore National Laboratory contains short abstracts/articles submitted by speakers. The topic areas covered include the following: Astronomical Imaging; biomedical imaging; vision/image display; imaging hardware; imaging software; Acoustic/oceanic imaging; microwave/acoustic imaging; computed tomography; physical imaging; imaging algorithms. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  11. Quantitative imaging of D-2-hydroxyglutarate (D2HG in selected histological tissue areas by a novel bioluminescence technique

    Directory of Open Access Journals (Sweden)

    Nadine Fabienne Voelxen

    2016-03-01

    Full Text Available AbstractPatients with malignant gliomas have a poor prognosis with average survival of less than one year. Whereas in other tumor entities the characteristics of tumor metabolism are successfully used for therapeutic approaches, such developments are very rare in brain tumors, notably in gliomas. One metabolic feature characteristic of gliomas, in particular diffuse astrocytomas and oligodendroglial tumors, is the variable content of D-2-hydroxyglutarate (D2HG, a metabolite, which was discovered first in this tumor entity. D2HG is generated in large amounts due to various gain-of–function mutations in the isocitrate dehydrogenases IDH-1 and IDH-2. Meanwhile, D2HG has been detected in several other tumor entities including intrahepatic bile-duct cancer, chondrosarcoma, acute myeloid leukemia, and angioimmunoblastic T-cell lymphoma. D2HG is barely detectable in healthy tissue (< 0.1 mM, but its concentration increases up to 35 mM in malignant tumor tissues. Consequently, the oncometabolite D2HG has gained increasing interest in the field of tumor metabolism. To facilitate its quantitative measurement without loss of spatial resolution at a microscopical level, we have developed a novel bioluminescence assay for determining D2HG in sections of snap-frozen tissue. The assay was verified independently by photometric tests and liquid chromatography / mass spectrometry (LC/MS. The novel technique allows the microscopically resolved determination of D2HG in a concentration range of 0 – 10 µmol/g tissue (wet weight. In combination with the already established bioluminescence imaging techniques for ATP, glucose, pyruvate, and lactate, the novel D2HG assay enables a comparative characterization of the metabolic profile of individual tumors in a further dimension.

  12. Determining the area of influence of depression cone in the vicinity of lignite mine by means of triangle method and LANDSAT TM/ETM+ satellite images.

    Science.gov (United States)

    Zawadzki, Jarosław; Przeździecki, Karol; Miatkowski, Zygmunt

    2016-01-15

    Problems with lowering of water table are common all over the world. Intensive pumping of water from aquifers for consumption, irrigation, industrial or mining purposes often causes groundwater depletion and results in the formation of cone of depression. This can severely decrease water pressure, even over vast areas, and can create severe problems such as degradation of agriculture or natural environment sometimes depriving people and animals of water supply. In this paper, the authors present a method for determining the area of influence of a groundwater depression cone resulting from prolonged drainage, by means of satellite images in optical, near infrared and thermal infrared bands from TM sensor (Thematic Mapper) and ETM+ sensor (Enhanced Thematic Mapper +) placed on Landsat 5 and Landsat 7 satellites. The research area was Szczercowska Valley (Pol. Kotlina Szczercowska), Central Poland, located within a range of influence of a groundwater drainage system of the lignite coal mine in Belchatow. It is the biggest lignite coal mine in Poland and one of the largest in Europe exerting an enormous impact on the environment. The main method of satellite data analysis for determining soil moisture, was the so-called triangle method. This method, based on TVDI (Temperature Vegetation Dryness Index) was supported by additional spatial analysis including ordinary kriging used in order to combine fragmentary information obtained from areas covered by meadows. The results obtained are encouraging and confirm the usefulness of the triangle method not only for soil moisture determination but also for assessment of the temporal and spatial changes in the area influenced by the groundwater depression cone. The range of impact of the groundwater depression cone determined by means of above-described remote sensing analysis shows good agreement with that determined by ground measurements. The developed satellite method is much faster and cheaper than in-situ measurements

  13. Determining the area of influence of depression cone in the vicinity of lignite mine by means of triangle method and LANDSAT TM/ETM+ satellite images.

    Science.gov (United States)

    Zawadzki, Jarosław; Przeździecki, Karol; Miatkowski, Zygmunt

    2016-01-15

    Problems with lowering of water table are common all over the world. Intensive pumping of water from aquifers for consumption, irrigation, industrial or mining purposes often causes groundwater depletion and results in the formation of cone of depression. This can severely decrease water pressure, even over vast areas, and can create severe problems such as degradation of agriculture or natural environment sometimes depriving people and animals of water supply. In this paper, the authors present a method for determining the area of influence of a groundwater depression cone resulting from prolonged drainage, by means of satellite images in optical, near infrared and thermal infrared bands from TM sensor (Thematic Mapper) and ETM+ sensor (Enhanced Thematic Mapper +) placed on Landsat 5 and Landsat 7 satellites. The research area was Szczercowska Valley (Pol. Kotlina Szczercowska), Central Poland, located within a range of influence of a groundwater drainage system of the lignite coal mine in Belchatow. It is the biggest lignite coal mine in Poland and one of the largest in Europe exerting an enormous impact on the environment. The main method of satellite data analysis for determining soil moisture, was the so-called triangle method. This method, based on TVDI (Temperature Vegetation Dryness Index) was supported by additional spatial analysis including ordinary kriging used in order to combine fragmentary information obtained from areas covered by meadows. The results obtained are encouraging and confirm the usefulness of the triangle method not only for soil moisture determination but also for assessment of the temporal and spatial changes in the area influenced by the groundwater depression cone. The range of impact of the groundwater depression cone determined by means of above-described remote sensing analysis shows good agreement with that determined by ground measurements. The developed satellite method is much faster and cheaper than in-situ measurements

  14. Advanced biomedical image analysis

    CERN Document Server

    Haidekker, Mark A

    2010-01-01

    "This book covers the four major areas of image processing: Image enhancement and restoration, image segmentation, image quantification and classification, and image visualization. Image registration, storage, and compression are also covered. The text focuses on recently developed image processing and analysis operators and covers topical research"--Provided by publisher.

  15. The analysis of spatial and temporal changes of land cover and land use in the reclaimed areas with the application of airborne orthophotomaps and LANDSAT images

    Science.gov (United States)

    Szostak, Marta; Wężyk, Piotr; Hawryło, Paweł; Pietrzykowski, Marcin

    2015-06-01

    The aim of this study was to investigate the possible use of geoinformatics tools and generally available geodata for mapping land cover/use on the reclaimed areas. The choice of subject was dictated by the growing number of such areas and the related problem of their restoration. Modern technology, including GIS, photogrammetry and remote sensing are relevant in assessing the reclamation effects and monitoring of changes taking place on such sites. The LULC classes mapping, supported with thorough knowledge of the operator, is useful tool for the proper reclamation process evaluation. The study was performed for two post-mine sites: reclaimed external spoil heap of the sulfur mine Machów and areas after exploitation of sulfur mine Jeziórko, which are located in the Tarnobrzeski district. The research materials consisted of aerial orthophotos, which were the basis of on-screen vectorization; LANDSAT satellite images, which were used in the pixel and object based classification; and the CORINE Land Cover database as a general reference to the global maps of land cover and land use.

  16. A method for monitoring building construction in urban sprawl areas using object-based analysis of Spot 5 images and existing GIS data

    Science.gov (United States)

    Durieux, Laurent; Lagabrielle, Erwann; Nelson, Andrew

    Urban sprawl has been identified as one of the most negative effects of global population growth on the environment and biodiversity. Frequent monitoring of urban sprawl is needed to limit the impact of this ongoing phenomenon. This paper proposes precise monitoring of building construction using an object-based classification methodology applied to Spot 5 images with a 2.5 m resolution. An application at a regional scale on Reunion Island in the Indian Ocean shows that this building extraction methodology has limitations in the production of reference urban maps because of difficulties in defining the shape and the number of buildings compared to classical photo-interpretation of aerial photography. However, these results are of great value for planning in urban sprawl areas where up-to-date information is lacking because of the rapid pace of house construction and residential development.

  17. Imaging hydrothermal systems associated with oceanic ridge: ambient noise and travel-time tomographies in the Reykjanes high-temperature area, SW-Iceland.

    Science.gov (United States)

    Jousset, Philippe; Ágústsson, Kristjan; Verdel, Arie; Blanck, Hanna; Franke, Steven; Specht, Sebastian; Stefánsson, Stefán; Tryggvason, Hörður; Erbas, Kemal; Deon, Fiorenza; Erlendsson, Ögmundur; Guðnason, Egill; Hersir, Gylfi; Ryberg, Trond; Halldórsdóttir, Sæunn; Weemstra, Cornelius; Bruhn, David; Flovenz, Ólafur; Friðleifsson, Ómar

    2015-04-01

    Analogue outcrops of hydrothermal fossil systems and simulating pressure/temperature conditions in the laboratory are classical methods for assessing supercritical conditions in magmatic environments. Scientific drilling is used when Earth surface sampled rocks cannot sufficiently explain past geological processes and when geophysical imaging does not sufficiently explain observed phenomena. However, our understanding of structural and dynamic characteristics of geothermal systems can be improved through application of advanced and/or innovative exploration technologies. Unlike resistivity imaging, active and passive seismic techniques have rarely been used in volcanic geothermal areas, because processing techniques were not adapted to geothermal conditions. Recent advances in volcano-seismology have introduced new processing techniques for assessing subsurface structures and controls on fluid flow in geothermal systems. We present here preliminary analyses of seismic records around a geothermal reservoir located both on-land and offshore along the Reykjanes Ridge, SW-Iceland. We deployed 214 on-land stations and 24 Ocean Bottom Seismometers since April 2014. We analyse more than 6 months of part of those records. We present first results of both travel-time tomography and ambient noise tomography and we discuss briefly implications for geothermal exploration in volcanic contexts.

  18. The potential of Sentinel 2 and PROBA-V images for supporting early warnings of particulate matter pollution episodes in Ploiesti urban area

    Science.gov (United States)

    Dunea, Daniel; Iordache, Stefania; Pohoata, Alin; Lungu, Emil; Ianache, Cornel; Ianache, Radu

    2016-04-01

    One of the major air quality stressors in the urban area is particulate matter (PM). PM includes dust, dirt, soot, smoke, and liquid droplets emitted into the air by various sources such as vehicles, factories, and construction activities. PM has been linked to asthma and other respiratory illnesses. Inner-city residents need timely access to air quality synthetic indicators for protecting their respiratory health. Access to air quality forecasts and real-time data can allow residents, especially children and elders, to reduce their exposure when PM levels in conjunction with other pollutants are of potential concern. Ploiesti city is an important industrial center, which experienced a rapid economic growth in the last decade. Its industrial activity is concentrated especially on the oil production and refining industry. Ploiesti is the only city in Europe surrounded by four oil refineries. Monitoring campaigns were carried out in 12 sampling points during the "rush" hours (7.00-12.00 a.m. and 3.00-7.00 p.m.) to assess the potential exposure to high PM levels using an optical portable monitoring system, which is measuring fine and submicrometric fractions with a laser beam (DusttrakTM DRX 8533EP with environmental enclosure). Inverse distance weighting algorithm was used to obtain potential isolines of concentrations at town's scale in GIS environment. NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT), respectively the backward trajectory type, was used to overview the contribution of long range transport from the most probable source region of the significant episodes characterized by PM rising of concentrations. Extraction of radiometric indicators from historical databases with multispectral images allowed the spatiotemporal characterization of land use and cloud distribution i.e. Sentinel 2 and PROBA-V (allowing specific characterization of NDVI, which provided canopy and surface reflectance in the pilot area). Resulted data were

  19. Digital image processing.

    Science.gov (United States)

    Seeram, Euclid

    2004-01-01

    Digital image processing is now commonplace in radiology, nuclear medicine and sonography. This article outlines underlying principles and concepts of digital image processing. After completing this article, readers should be able to: List the limitations of film-based imaging. Identify major components of a digital imaging system. Describe the history and application areas of digital image processing. Discuss image representation and the fundamentals of digital image processing. Outline digital image processing techniques and processing operations used in selected imaging modalities. Explain the basic concepts and visualization tools used in 3-D and virtual reality imaging. Recognize medical imaging informatics as a new area of specialization for radiologic technologists. PMID:15352557

  20. Microwave imaging

    CERN Document Server

    Pastorino, Matteo

    2010-01-01

    An introduction to the most relevant theoretical and algorithmic aspects of modern microwave imaging approaches Microwave imaging-a technique used in sensing a given scene by means of interrogating microwaves-has recently proven its usefulness in providing excellent diagnostic capabilities in several areas, including civil and industrial engineering, nondestructive testing and evaluation, geophysical prospecting, and biomedical engineering. Microwave Imaging offers comprehensive descriptions of the most important techniques so far proposed for short-range microwave imaging-in

  1. Estimation of radiation dose and image quality of coronary 320-row area detector CT angiography by optimal prospective ECG-gated protocols for different heart rate

    International Nuclear Information System (INIS)

    The purpose of this study is to estimate radiation dose and image quality of electrocardiogram (ECG)-gated coronary 320-area detector CT (ADCT) angiography which was acquired using the protocols that were considered as optimal methods for different heart rates (HR) in 1031 consecutive patients (M/F =580/451, 65±12 yr) without arrhythmias. We set up 5 protocols for 320-ADCT based on the relationship among heart rates, temporal resolution, gantry rotation speed, optimal reconstruction phase and slow filling phase on 64-multidetector-row computed tomography (MDCT), id est (ie), 1) mid-diastolic (75% of risk ratio (RR)) 1 beat scan (moderate disability (MD) 1 beat, N=761 (73.8%)) for HR ≤60, 2) mid-diastolic (75% of RR) 2 beat scan (MD 2 beat, N=135) for 61≤ HR ≤65, 3) end-systolic and mid-diastolic (37-80% of RR) 2 beat scan (embryonic stem (ES)-MD 2 beat, N=92) for 66≤ HR ≤75, 4) end-systolic (R +280-430 ms) 2 beat scan (ES 2 beat, N=21) for 76≤ HR ≤80, and 5) end-systolic (R +250-400 ms) 3 beat scan (ES 3 beat, N=22) for 81≤ HR ≤105. Image quality was classified into 3 categories (excellent (3 points), acceptable (2 points), and unacceptable (1 point)). Scanning time, DLP.e and image quality score were 1.4±0.1 s, 220±59 mGy·cm, 3.0±0.2 points in MD 1 beat, 2.2±0.2 s, 434±118 mGy·cm, 2.9±0.3 points in MD 2 beat, 2.1±0.2 s, 729±229 mGy·cm, 2.7±0.5 points in ES-MD 2 beat, 1.9±0.1 s, 432±148 mGy·cm, 2.2±0.6 points in ES 2 beat, and 2.4±0.2 s, 669±152 mGy·cm, 2.3±0.6 points in ES 3 beat respectively. In conclusion, the prospective ECG-gated scan protocol for coronary 320-ADCT angiography in any HR group was considered reasonable and proper for image quality and radiation dose. (author)

  2. Factors contributing to accuracy in the estimation of the woody canopy leaf area density profile using 3D portable lidar imaging.

    Science.gov (United States)

    Hosoi, Fumiki; Omasa, Kenji

    2007-01-01

    Factors that contribute to the accuracy of estimating woody canopy's leaf area density (LAD) using 3D portable lidar imaging were investigated. The 3D point cloud data for a Japanese zelkova canopy [Zelkova serrata (Thunberg) Makino] were collected using a portable scanning lidar from several points established on the ground and at 10 m above the ground. The LAD profiles were computed using voxel-based canopy profiling (VCP). The best LAD results [a root-mean-square error (RMSE) of 0.21 m(2) m(-3)] for the measurement plot (corresponding to an absolute LAI error of 9.5%) were obtained by compositing the ground-level and 10 m measurements. The factors that most strongly affected estimation accuracy included the presence of non-photosynthetic tissues, distribution of leaf inclination angles, number (N) of incident laser beams in each region within the canopy, and G(theta(m)) (the mean projection of a unit leaf area on a plane perpendicular to the direction of the laser beam at the measurement zenith angle of theta(m)). The influences of non-photosynthetic tissues and leaf inclination angle on the estimates amounted to 4.2-32.7% and 7.2-94.2%, respectively. The RMSE of the LAD estimations was expressed using a function of N and G(theta(m)). PMID:17977852

  3. Mapping Fish Community Variables by Integrating Field and Satellite Data, Object-Based Image Analysis and Modeling in a Traditional Fijian Fisheries Management Area

    Directory of Open Access Journals (Sweden)

    Stacy Jupiter

    2011-03-01

    Full Text Available The use of marine spatial planning for zoning multi-use areas is growing in both developed and developing countries. Comprehensive maps of marine resources, including those important for local fisheries management and biodiversity conservation, provide a crucial foundation of information for the planning process. Using a combination of field and high spatial resolution satellite data, we use an empirical procedure to create a bathymetric map (RMSE 1.76 m and object-based image analysis to produce accurate maps of geomorphic and benthic coral reef classes (Kappa values of 0.80 and 0.63; 9 and 33 classes, respectively covering a large (>260 km2 traditional fisheries management area in Fiji. From these maps, we derive per-pixel information on habitat richness, structural complexity, coral cover and the distance from land, and use these variables as input in models to predict fish species richness, diversity and biomass. We show that random forest models outperform five other model types, and that all three fish community variables can be satisfactorily predicted from the high spatial resolution satellite data. We also show geomorphic zone to be the most important predictor on average, with secondary contributions from a range of other variables including benthic class, depth, distance from land, and live coral cover mapped at coarse spatial scales, suggesting that data with lower spatial resolution and lower cost may be sufficient for spatial predictions of the three fish community variables.

  4. Monitoring vegetation recovery in fire-affected areas using temporal profiles of spectral signal from time series MODIS and LANDSAT satellite images

    Science.gov (United States)

    Georgopoulou, Danai; Koutsias, Nikos

    2015-04-01

    Vegetation phenology is an important element of vegetation characteristics that can be useful in vegetation monitoring especially when satellite remote sensing observations are used. In that sense temporal profiles extracted from spectral signal of time series MODIS and LANDSAT satellite images can be used to characterize vegetation phenology and thus to be helpful for monitoring vegetation recovery in fire-affected areas. The aim of this study is to explore the vegetation recovery pattern of the catastrophic wildfires that occurred in Peloponnisos, southern Greece, in 2007. These fires caused the loss of 67 lives and were recognized as the most extreme natural disaster in the country's recent history. Satellite remote sensing data from MODIS and LANDSAT satellites in the period from 2000 to 2014 were acquired and processed to extract the temporal profiles of the spectral signal for selected areas within the fire-affected areas. This dataset and time period analyzed together with the time that these fires occurred gave the opportunity to create temporal profiles seven years before and seven years after the fire. The different scale of the data used gave us the chance to understand how vegetation phenology and therefore the recovery patterns are influenced by the spatial resolution of the satellite data used. Different metrics linked to key phenological events have been created and used to assess vegetation recovery in the fire-affected areas. Our analysis was focused in the main land cover types that were mostly affected by the 2007 wildland fires. Based on CORINE land-cover maps these were agricultural lands highly interspersed with large areas of natural vegetation followed by sclerophyllous vegetation, transitional woodland shrubs, complex cultivation patterns and olive groves. Apart of the use of the original spectral data we estimated and used vegetation indices commonly found in vegetation studies as well as in burned area mapping studies. In this study we

  5. A Novel Technique Based on the Combination of Labeled Co-Occurrence Matrix and Variogram for the Detection of Built-up Areas in High-Resolution SAR Images

    Directory of Open Access Journals (Sweden)

    Na Li

    2014-04-01

    Full Text Available Interests in synthetic aperture radar (SAR data analysis is driven by the constantly increased spatial resolutions of the acquired images, where the geometries of scene objects can be better defined than in lower resolution data. This paper addresses the problem of the built-up areas extraction in high-resolution (HR SAR images, which can provide a wealth of information to characterize urban environments. Strong backscattering behavior is one of the distinct characteristics of built-up areas in a SAR image. However, in practical applications, only a small portion of pixels characterizing the built-up areas appears bright. Thus, specific texture measures should be considered for identifying these areas. This paper presents a novel texture measure by combining the proposed labeled co-occurrence matrix technique with the specific spatial variability structure of the considered land-cover type in the fuzzy set theory. The spatial variability is analyzed by means of variogram, which reflects the spatial correlation or non-similarity associated with a particular terrain surface. The derived parameters from the variograms are used to establish fuzzy functions to characterize the built-up class and non built-up class, separately. The proposed technique was tested on TerraSAR-X images acquired of Nanjing (China and Barcelona (Spain, and on a COSMO-SkyMed image acquired of Hangzhou (China. The obtained classification accuracies point out the effectiveness of the proposed technique in identifying and detecting built-up areas.

  6. IMAGE INTERPRETATION OF COASTAL AREAS

    OpenAIRE

    M. A. Lazaridou

    2012-01-01

    Coasts were formed with the overall shape of earth's surface. Τhey represent a landform, as determined by the science of geomorphology. Being the boundary between land and sea, they present important features – particularities such as water currents, waves, winds, estuaries, drainage network, pollution etc. Coasts are examined at various levels: continents – oceans, states – large seas, as for example Mediterranean Sea. Greece, because of its horizontal and vertical partitio...

  7. Areas where bedsores occur (image)

    Science.gov (United States)

    Bedsores, also known as pressure sores or decubitus ulcers, are a breakdown and ulceration of tissue due ... heels of the feet, are most susceptible to bedsores. Non-mobile patients are vulnerable to the formation ...

  8. Color blobs in cortical areas V1 and V2 of the new world monkey Callithrix jacchus, revealed by non-differential optical imaging.

    Science.gov (United States)

    Valverde Salzmann, Matthias F; Bartels, Andreas; Logothetis, Nikos K; Schüz, Almut

    2012-06-01

    Color vision is reserved to only few mammals, such as Old World monkeys and humans. Most Old World monkeys are trichromats. Among them, macaques were shown to exhibit functional domains of color-selectivity, in areas V1 and V2 of the visual cortex. Such color domains have not yet been shown in New World monkeys. In marmosets a sex-linked dichotomy results in dichromatic and trichromatic genotypes, rendering most male marmosets color-blind. Here we used trichromatic female marmosets to examine the intrinsic signal response in V1 and V2 to chromatic and achromatic stimuli, using optical imaging. To activate the subsystems individually, we used spatially homogeneous isoluminant color opponent (red/green, blue/yellow) and hue versus achromatic flicker (red/gray, green/gray, blue/gray, yellow/gray), as well as achromatic luminance flicker. In contrast to previous optical imaging studies in marmosets, we find clearly segregated color domains, similar to those seen in macaques. Red/green and red/gray flicker were found to be the appropriate stimulus for revealing color domains in single-condition maps. Blue/gray and blue/yellow flicker stimuli resulted in faint patch-patterns. A recently described multimodal vessel mapping approach allowed for an accurate alignment of the functional and anatomical datasets. Color domains were tightly colocalized with cytochrome oxidase blobs in V1 and with thin stripes in V2. Thus, our findings are in accord with 2-Deoxy-D-glucose studies performed in V1 of macaques and studies on color representation in V2. Our results suggest a similar organization of early cortical color processing in trichromats of both Old World and New World monkeys. PMID:22674264

  9. A Cross-sectional Study of Correlation of Body Image Anxiety with Social Phobia and Their Association with Depression in the Adolescents from a Rural Area of Sangli District in India

    OpenAIRE

    Vivek Baliram Waghachavare; Quraishi, Sanjay R.; Dhumale, Girish B.; Alka D Gore

    2014-01-01

    Background: Prevailing socio-cultural influences lead females to desire a thin body and males a muscular body, especially in adolescents. This results in body image anxiety which may lead to social phobia. Together they can develop depression. The aim was to study the correlation of body image anxiety with social phobia and their association with depression, among adolescents. Methods: This was a cross-sectional study conducted in randomly selected colleges from a rural area of Sangli dis...

  10. 基于区域信息的水平集医学图像分割%Medical image segmentation based on level set area information

    Institute of Scientific and Technical Information of China (English)

    陈静; 朱家明; 盛朗; 居小平

    2014-01-01

    医学图像分割是医学诊断中非常重要的部分,针对医学图像分割往往出现边缘泄漏和不完全分割等问题,本文提出一种基于区域信息的水平集图像分割方法。该方法通过引入符号压力函数来取代传统的停止函数,可以有效地解决曲线初始位置敏感的问题,同时使得演化曲线摆脱了单方向演化的缺陷,演化曲线根据区域信息来选择演化方向。通过构造新的速度函数可以有效地控制速度大小,当演化曲线接近目标边缘时,速度值较小,可以有效避免边缘泄漏。当曲线远离目标边缘时,速度值很大,节省演化所需的时间。%Medical image segmentation is a very important part in medical diagnosis. In order to solve edge leakage, incomplete segmentation and other issues, a level set image segmentation based on area information was proposed. By introducing signed pressure force to replace the traditional stop function,this method not only can effectively slove the initial curve position sensitive issue, but also make the evolution of the curve out of the single direction defects , the direction of the curve is automatically selected through area information. The size of speed can be effectively controlled by the new speed function. When the curve close to the edge of target, the speed is small, so that the curve can avoid the edge of target leakage. The new speed functioncan save time.when the curve far away from the edge of target,the speed is large.

  11. Spatio-temporal prediction of leaf area index of rubber plantation using HJ-1A/1B CCD images and recurrent neural network

    Science.gov (United States)

    Chen, Bangqian; Wu, Zhixiang; Wang, Jikun; Dong, Jinwei; Guan, Liming; Chen, Junming; Yang, Kai; Xie, Guishui

    2015-04-01

    Rubber (Hevea brasiliensis) plantations are one of the most important economic forest in tropical area. Retrieving leaf area index (LAI) and its dynamics by remote sensing is of great significance in ecological study and production management, such as yield prediction and post-hurricane damage evaluation. Thirteen HJ-1A/1B CCD images, which possess the spatial advantage of Landsat TM/ETM+ and 2-days temporal resolution of MODIS, were introduced to predict the spatial-temporal LAI of rubber plantation on Hainan Island by Nonlinear AutoRegressive networks with eXogenous inputs (NARX) model. Monthly measured LAIs at 30 stands by LAI-2000 between 2012 and 2013 were used to explore the LAI dynamics and their relationship with spectral bands and seven vegetation indices, and to develop and validate model. The NARX model, which was built base on input variables of day of year (DOY), four spectral bands and weight difference vegetation index (WDVI), possessed good accuracies during the model building for the data set of training (N = 202, R2 = 0.98, RMSE = 0.13), validation (N = 43, R2 = 0.93, RMSE = 0.24) and testing (N = 43, R2 = 0.87, RMSE = 0.31), respectively. The model performed well during field validation (N = 24, R2 = 0.88, RMSE = 0.24) and most of its mapping results showed better agreement (R2 = 0.54-0.58, RMSE = 0.47-0.71) with the field data than the results of corresponding stepwise regression models (R2 = 0.43-0.51, RMSE = 0.52-0.82). Besides, the LAI statistical values from the spatio-temporal LAI maps and their dynamics, which increased dramatically from late March (2.36 ± 0.59) to early May (3.22 ± 0.64) and then gradually slow down until reached the maximum value in early October (4.21 ± 0.87), were quite consistent with the statistical results of the field data. The study demonstrates the feasibility and reliability of retrieving spatio-temporal LAI of rubber plantations by an artificial neural network (ANN) approach, and provides some insight on the

  12. pH-Responsive biodegradable polymeric micelles with anchors to interface magnetic nanoparticles for MR imaging in detection of cerebral ischemic area

    Science.gov (United States)

    Yang, Hong Yu; Jang, Moon-Sun; Gao, Guang Hui; Lee, Jung Hee; Lee, Doo Sung

    2016-06-01

    A novel type of pH-responsive biodegradable copolymer was developed based on methyloxy-poly(ethylene glycol)-block-poly[dopamine-2-(dibutylamino) ethylamine-l-glutamate] (mPEG-b-P(DPA-DE)LG) and applied to act as an intelligent nanocarrier system for magnetic resonance imaging (MRI). The mPEG-b-P(DPA-DE)LG copolymer was synthesized by a typical ring opening polymerization of N-carboxyanhydrides (NCAs-ROP) using mPEG-NH2 as a macroinitiator, and two types of amine-terminated dopamine groups and pH-sensitive ligands were grafted onto a side chain by a sequential aminolysis reaction. This design greatly benefits from the addition of the dopamine groups to facilitate self-assembly, as these groups can act as high-affinity anchors for iron oxide nanoparticles, thereby increasing long-term stability at physiological pH. The mPEG moiety in the copolymers helped the nanoparticles to remain well-dispersed in an aqueous solution, and pH-responsive groups could control the release of hydrophobic Fe3O4 nanoparticles in an acidic environment. The particle size of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles was measured by dynamic light scattering (DLS) and cryo-TEM. The superparamagnetic properties of the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles were confirmed by a superconducting quantum interference device (SQUID). T2-weighted magnetic resonance imaging (MRI) of Fe3O4-loaded mPEG-b-P(DPA-DE)LG phantoms exhibited enhanced negative contrast with an r2 relaxivity of approximately 106.7 mM-1 s-1. To assess the ability of the Fe3O4-loaded mPEG-P(DE-DPA)LG micelles to act as MRI probes, we utilized a cerebral ischemia disease rat model with acidic tissue. We found that a gradual change in contrast in the cerebral ischemic area could be visualized by MRI after 1 h, and maximal signal loss was detected after 24 h post-injection. These results demonstrated that the Fe3O4-loaded mPEG-b-P(DPA-DE)LG micelles can act as pH-triggered MRI probes for diagnostic imaging of acidic

  13. Image based remote sensing method for modeling black-eyed beans (Vigna unguiculata) Leaf Area Index (LAI) and Crop Height (CH) over Cyprus

    Science.gov (United States)

    Papadavid, Giorgos; Fasoula, Dionysia; Hadjimitsis, Michael; Skevi Perdikou, P.; Hadjimitsis, Diofantos

    2013-03-01

    In this paper, Leaf Area Index (LAI) and Crop Height (CH) are modeled to the most known spectral vegetation index — NDVI — using remotely sensed data. This approach has advantages compared to the classic approaches based on a theoretical background. A GER-1500 field spectro-radiometer was used in this study in order to retrieve the necessary spectrum data for estimating a spectral vegetation index (NDVI), for establishing a semiempirical relationship between black-eyed beans' canopy factors and remotely sensed data. Such semi-empirical models can be used then for agricultural and environmental studies. A field campaign was undertaken with measurements of LAI and CH using the Sun-Scan canopy analyzer, acquired simultaneously with the spectroradiometric (GER1500) measurements between May and June of 2010. Field spectroscopy and remotely sensed imagery have been combined and used in order to retrieve and validate the results of this study. The results showed that there are strong statistical relationships between LAI or CH and NDVI which can be used for modeling crop canopy factors (LAI, CH) to remotely sensed data. The model for each case was verified by the factor of determination. Specifically, these models assist to avoid direct measurements of the LAI and CH for all the dates for which satellite images are available and support future users or future studies regarding crop canopy parameters.

  14. Built-up Area Change Analysis in Hanoi Using Support Vector Machine Classification of Landsat Multi-Temporal Image Stacks and Population Data

    Directory of Open Access Journals (Sweden)

    Duong H. Nong

    2015-12-01

    Full Text Available In 1986, the Government of Vietnam implemented free market reforms known as Doi Moi (renovation that provided private ownership of farms and companies, and encouraged deregulation and foreign investment. Since then, the economy of Vietnam has achieved rapid growth in agricultural and industrial production, construction and housing, and exports and foreign investments, each of which have resulted in momentous landscape transformations. One of the most evident changes is urbanization and an accompanying loss of agricultural lands and open spaces. These rapid changes pose enormous challenges for local populations as well as planning authorities. Accurate and timely data on changes in built-up urban environments are essential for supporting sound urban development. In this study, we applied the Support Vector Machine classification (SVM to multi-temporal stacks of Landsat Thematic Mapper (TM and Enhanced Thematic Mapper Plus (ETM+ images from 1993 to 2010 to quantify changes in built-up areas. The SVM classification algorithm produced a highly accurate map of land cover change with an overall accuracy of 95%. The study showed that most urban expansion occurred in the periods 2001–2006 and 2006–2010. The analysis was strengthened by the incorporation of population and other socio-economic data. This study provides state authorities a means to examine correlations between urban growth, spatial expansion, and other socio-economic factors in order to not only assess patterns of urban growth but also become aware of potential environmental, social, and economic problems.

  15. Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area

    Science.gov (United States)

    Stephenson, William J.; Odum, Jackson K.; Wicks, Chuck; Pratt, Thomas L.; Blakely, Richard J.

    2016-01-01

    In 2001, a rare swarm of small, shallow earthquakes beneath the city of Spokane, Washington, caused ground shaking as well as audible booms over a five‐month period. Subsequent Interferometric Synthetic Aperture Radar (InSAR) data analysis revealed an area of surface uplift in the vicinity of the earthquake swarm. To investigate the potential faults that may have caused both the earthquakes and the topographic uplift, we collected ∼3  km of high‐resolution seismic‐reflection profiles to image the upper‐source region of the swarm. The two profiles reveal a complex deformational pattern within Quaternary alluvial, fluvial, and flood deposits, underlain by Tertiary basalts and basin sediments. At least 100 m of arching on a basalt surface in the upper 500 m is interpreted from both the seismic profiles and magnetic modeling. Two west‐dipping faults deform Quaternary sediments and project to the surface near the location of the Spokane fault defined from modeling of the InSAR data.

  16. NIAID Biodefense Image Library

    Science.gov (United States)

    ... Content Marketing Share this: Main Content Area Image Library These high-resolution (300 dpi) images may be ... for Disease Control and Prevention public health image library . Smallpox Vaccination Study-1 Smallpox vaccination dilution study: ...

  17. Multi-institutional Quantitative Evaluation and Clinical Validation of Smart Probabilistic Image Contouring Engine (SPICE) Autosegmentation of Target Structures and Normal Tissues on Computer Tomography Images in the Head and Neck, Thorax, Liver, and Male Pelvis Areas

    NARCIS (Netherlands)

    Zhu, Mingyao; Bzdusek, Karl; Brink, Carsten; Eriksen, Jesper Grau; Hansen, Olfred; Jensen, Helle Anita; Gay, Hiram A.; Thorstad, Wade; Widder, Joachim; Brouwer, Charlotte L.; Steenbakkers, Roel J. H. M.; Vanhauten, Hubertus A. M.; Cao, Jeffrey Q.; McBrayne, Gail; Patel, Salil H.; Cannon, Donald M.; Hardcastle, Nicholas; Tome, Wolfgang A.; Guckenberg, Matthias; Parikh, Parag J.

    2013-01-01

    Purpose: Clinical validation and quantitative evaluation of computed tomography (CT) image autosegmentation using Smart Probabilistic Image Contouring Engine (SPICE). Methods and Materials: CT images of 125 treated patients (32 head and neck [HN], 40 thorax, 23 liver, and 30 prostate) in 7 independe

  18. Application of a-Si:H radiation detectors in medical imaging

    International Nuclear Information System (INIS)

    Monte Carlo simulations of a proposed a-Si:H-based current-integrating gamma camera were performed. The analysis showed that the intrinsic resolution of such a camera was 1 ∼ 2.5 mm, which is somewhat better than that of a conventional gamma camera, and that the greater blurring, due to the detection of scattered γ-rays, could be reduced considerably by image restoration techniques. This proposed gamma camera would be useful for imaging shallow organs such as the thyroid. Prototype charge-storage a-Si:H pixel detectors for such a camera were designed, constructed and tested. The detectors could store signal charge as long as 5 min at -26C. The thermal generation current in reverse biased a-Si:H p-i-n photodetectors was investigated, and the Poole-Frenkel effect was found to be the most significant source of the thermal generation current. Based on the Poole-Frenkel effect, voltage- and time-dependent thermal generation current was modeled. Using the model, the operating conditions of the proposed a-Si:H gamma camera, such as the operating temperature, the operating bias and the γ-scan period, could be predicted. The transient photoconductive gain mechanism in various a-Si:H devices was investigated for applications in digital radiography. Using the a-Si:H photoconductors in n-i-n configuration in pixel arrays, enhancement in signal collection (more than 200 times higher signal level) can be achieved in digital radiography, compared to the ordinary p-i-n type a-Si:H x-ray imaging arrays

  19. Identificação e mapeamento de áreas de milho na região sul do Brasil utilizando imagens MODIS Identification and mapping of maize areas in the south region of Brazil using MODIS images

    Directory of Open Access Journals (Sweden)

    José L. R. Yi

    2007-12-01

    Full Text Available O presente trabalho teve como proposta avaliar a identificação e o mapeamento das áreas de milho da região noroeste do Estado do Rio Grande do Sul a partir de dados multitemporais do sensor MODIS (Moderate Resolution Imaging Spectroradiometer a bordo do satélite Earth Observing System - EOS-AM (Terra. O algoritmo de classificação supervisionada Spectral Angle Mapper (SAM foi aplicado com sucesso em uma série multitemporal de imagens EVI pré-processadas. Verificou-se que as áreas classificadas como milho na imagem coincidiam plenamente com áreas mais extensas ou contínuas (> 90 ha de milho. Áreas de menor extensão ou localizadas em encostas de morros, ao lado de vegetação arbórea, não foram detectadas pelo classificador devido à baixa resolução espacial das imagens. A maior utilidade prática da identificação e da classificação digital das áreas de milho obtidas das imagens MODIS está na sua aplicação para isolar ou complementar o mapeamento das áreas agrícolas visando ao seu monitoramento a partir de diferentes índices de vegetação, derivados de imagens de alta resolução temporal e baixa resolução espacial.The present work had the proposal of evaluating the identification and mapping of maize areas in the northwestern region of the State of Rio Grande do Sul using multi-temporal data from MODIS (Moderate Resolution Imaging Spectroradiometer sensor on board of the Earth Observing System satellite - EOS-AM (Terra. The supervised classification algorithm Spectral Angle Mapper (SAM was successfully applied in a multi-temporal series of pre-processed EVI images. It was verified that the areas classified as maize in the image fully agree with more extensive or continuous maize areas (> 90 ha. Small or hillsides maize areas having close to shrub and wood vegetation were not detected by the classifier mainly due low spatial resolution of images. The main practical utility of maize’s areas digital classification

  20. Automated Image Intelligence Adaptive Sensor Management System for High Altitude Long Endurance UAVs in a Dynamic and Anti-Access Area Denial Environment

    Science.gov (United States)

    Kim, Gi Young

    The problem we investigate deals with an Image Intelligence (IMINT) sensor allocation schedule for High Altitude Long Endurance UAVs in a dynamic and Anti-Access Area Denial (A2AD) environment. The objective is to maximize the Situational Awareness (SA) of decision makers. The value of SA can be improved in two different ways. First, if a sensor allocated to an Areas of Interest (AOI) detects target activity, then the SA value will be increased. Second, the SA value increases if an AOI is monitored for a certain period of time, regardless of target detections. These values are functions of the sensor allocation time, sensor type and mode. Relatively few studies in the archival literature have been devoted to an analytic, detailed explanation of the target detection process, and AOI monitoring value dynamics. These two values are the fundamental criteria used to choose the most judicious sensor allocation schedule. This research presents mathematical expressions for target detection processes, and shows the monitoring value dynamics. Furthermore, the dynamics of target detection is the result of combined processes between belligerent behavior (target activity) and friendly behavior (sensor allocation). We investigate these combined processes and derive mathematical expressions for simplified cases. These closed form mathematical models can be used for Measures of Effectiveness (MOEs), i.e., target activity detection to evaluate sensor allocation schedules. We also verify these models with discrete event simulations which can also be used to describe more complex systems. We introduce several methodologies to achieve a judicious sensor allocation schedule focusing on the AOI monitoring value. The first methodology is a discrete time integer programming model which provides an optimal solution but is impractical for real world scenarios due to its computation time. Thus, it is necessary to trade off the quality of solution with computation time. The Myopic Greedy