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Sample records for proximity-focused streak camera

  1. Streak camera meeting summary

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bliss, David E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    Streak cameras are important for high-speed data acquisition in single event experiments, where the total recorded information (I) is shared between the number of measurements (M) and the number of samples (S). Topics of this meeting included: streak camera use at the national laboratories; current streak camera production; new tube developments and alternative technologies; and future planning. Each topic is summarized in the following sections.

  2. Streak camera techniques

    Energy Technology Data Exchange (ETDEWEB)

    Avara, R.

    1977-06-01

    An introduction to streak camera geometry, experimental techniques, and limitations are presented. Equations, graphs and charts are included to provide useful data for optimizing the associated optics to suit each experiment. A simulated analysis is performed on simultaneity and velocity measurements. An error analysis is also performed for these measurements utilizing the Monte Carlo method to simulate the distribution of uncertainties associated with simultaneity-time measurements.

  3. Demonstration of a Far Infrared Streak Camera.

    NARCIS (Netherlands)

    Drabbels, M.M.J.E.; Lankhuijzen, G.M.; Noordam, L.D.

    1998-01-01

    An atomic infrared (IR) streak camera is demonstrated that operates in the mid- and far-infrared (λ = 5-85 μm), well beyond the long wavelength cutoff of conventional streak cameras. The temporal and spectral characteristics of the streak camera are determined using the FELIX free-electron laser as

  4. C.C.D. Readout Of A Picosecond Streak Camera With An Intensified C.C.D.

    Science.gov (United States)

    Lemonier, M.; Richard, J. C.; Cavailler, C.; Mens, A.; Raze, G.

    1985-02-01

    This paper deals with a digital streak camera readout device. The device consists in a low light level television camera made of a solid state C.C.D. array coupled to an image intensifier associated to a video-digitizer coupled to a micro-computer system. The streak camera images are picked-up as a video signal, digitized and stored. This system allows the fast recording and the automatic processing of the data provided by the streak tube. Starting from the output screen of the streak camera, the constitutive elements are : - A fiber optic taper (A.O. Scientific Instruments) set in contact with the fiber optic output window of the streak tube achieves the image demagnification ; - A double proximity focused image intensifier (RTC - XX1410 SP) achieves the bright-ness amplification without any distortion ; - A second fiber optic taper achieves the dimensional matching between intensifier output and C.C.D. sensitive area ;

  5. Traveling wave deflector design for femtosecond streak camera

    Science.gov (United States)

    Pei, Chengquan; Wu, Shengli; Luo, Duan; Wen, Wenlong; Xu, Junkai; Tian, Jinshou; Zhang, Minrui; Chen, Pin; Chen, Jianzhong; Liu, Rong

    2017-05-01

    In this paper, a traveling wave deflection deflector (TWD) with a slow-wave property induced by a microstrip transmission line is proposed for femtosecond streak cameras. The pass width and dispersion properties were simulated. In addition, the dynamic temporal resolution of the femtosecond camera was simulated by CST software. The results showed that with the proposed TWD a femtosecond streak camera can achieve a dynamic temporal resolution of less than 600 fs. Experiments were done to test the femtosecond streak camera, and an 800 fs dynamic temporal resolution was obtained. Guidance is provided for optimizing a femtosecond streak camera to obtain higher temporal resolution.

  6. Traveling wave deflector design for femtosecond streak camera

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Chengquan; Wu, Shengli [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); Luo, Duan [Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wen, Wenlong [Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); Xu, Junkai [Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Tian, Jinshou, E-mail: tianjs@opt.ac.cn [Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006 (China); Zhang, Minrui; Chen, Pin [Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Jianzhong [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); Liu, Rong [Xi' an Technological University, Xi' an 710021 (China)

    2017-05-21

    In this paper, a traveling wave deflection deflector (TWD) with a slow-wave property induced by a microstrip transmission line is proposed for femtosecond streak cameras. The pass width and dispersion properties were simulated. In addition, the dynamic temporal resolution of the femtosecond camera was simulated by CST software. The results showed that with the proposed TWD a femtosecond streak camera can achieve a dynamic temporal resolution of less than 600 fs. Experiments were done to test the femtosecond streak camera, and an 800 fs dynamic temporal resolution was obtained. Guidance is provided for optimizing a femtosecond streak camera to obtain higher temporal resolution.

  7. AIP GHz modulation detection using a streak camera: Suitability of streak cameras in the AWAKE experiment

    CERN Document Server

    Rieger, K; Reimann, O; Muggli, P

    2017-01-01

    Using frequency mixing, a modulated light pulse of ns duration is created. We show that, with a ps-resolution streak camera that is usually used for single short pulse measurements, we can detect via an FFT detection approach up to 450 GHz modulation in a pulse in a single measurement. This work is performed in the context of the AWAKE plasma wakefield experiment where modulation frequencies in the range of 80–280 GHz are expected.

  8. Sub-picosecond x-ray streak camera development for laser fusion diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Lieber, A.J.; Sutphin, H.D.; Webb, C.B.; Williams, A.H.

    1976-01-01

    In laser-fusion interactions the effectiveness of coupling laser energy into target compression can be followed by obtaining spatial and temporal information on x-radiation emitted by the target. Microballoon targets now used require temporal resolution of better than a few picoseconds to track accurately target collapse and disassembly. Instabilities of two picoseconds or less are predicted for the process. Most streak cameras are based upon a sector-focused streak tube, which in the design limit is capable of only about 10 ps x-ray resolution. Therefore, a new tube, based upon the proximity-focused or wafer intensifier was developed as a laser-fusion diagnostic capable in the design limit of delivering truly sub-picosecond x-ray resolution. A new power supply was also developed to drive the streak tube. Together, a camera has resulted with true picosecond capability, small size, high sensitivity, broad dynamic range, high spatial resolution, and very low jitter. The system has proved 98 percent reliable in over 300 laser shots providing data on the collapse of microballoons when irradiated by a dual beam Nd:YAG laser. Theoretical predictions of 2.5 to 3 ps resolution are consistent with experimental data. A visible variant of the design now under construction is expected to give sub-picosecond resolution with advantages similar to the x-ray system.

  9. Picosecond X-ray streak camera dynamic range measurement

    Energy Technology Data Exchange (ETDEWEB)

    Zuber, C., E-mail: celine.zuber@cea.fr; Bazzoli, S.; Brunel, P.; Gontier, D.; Raimbourg, J.; Rubbelynck, C.; Trosseille, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Fronty, J.-P.; Goulmy, C. [Photonis SAS, Avenue Roger Roncier, BP 520, 19106 Brive Cedex (France)

    2016-09-15

    Streak cameras are widely used to record the spatio-temporal evolution of laser-induced plasma. A prototype of picosecond X-ray streak camera has been developed and tested by Commissariat à l’Énergie Atomique et aux Énergies Alternatives to answer the Laser MegaJoule specific needs. The dynamic range of this instrument is measured with picosecond X-ray pulses generated by the interaction of a laser beam and a copper target. The required value of 100 is reached only in the configurations combining the slowest sweeping speed and optimization of the streak tube electron throughput by an appropriate choice of high voltages applied to its electrodes.

  10. Improved approach to characterizing and presenting streak camera performance

    Energy Technology Data Exchange (ETDEWEB)

    Wiedwald, J.D.; Jones, B.A.

    1985-07-15

    The performance of a streak camera recording system is strongly linked to the technique used to amplify, detect and quantify the streaked image. At the Lawrence Livermore National Laboratory (LLNL) streak camera images have been recorded both on film and by fiber-optically coupling to charge-coupled devices (CCD's). During the development of a new process for recording these images (lens coupling the image onto a cooled CCD) the definitions of important performance characteristics such as resolution and dynamic range were re-examined. As a result of this development, these performance characteristics are now presented to the streak camera user in a more useful format than in the past. This paper describes how these techniques are used within the Laser Fusion Program at LLNL. The system resolution is presented as a modulation transfer function, including the seldom reported effects that flare and light scattering have at low spatial frequencies. Data are presented such that a user can adjust image intensifier gain and pixel averaging to optimize the useful dynamic range in any particular application.

  11. Design of microcontroller based system for automation of streak camera.

    Science.gov (United States)

    Joshi, M J; Upadhyay, J; Deshpande, P P; Sharma, M L; Navathe, C P

    2010-08-01

    A microcontroller based system has been developed for automation of the S-20 optical streak camera, which is used as a diagnostic tool to measure ultrafast light phenomenon. An 8 bit MCS family microcontroller is employed to generate all control signals for the streak camera. All biasing voltages required for various electrodes of the tubes are generated using dc-to-dc converters. A high voltage ramp signal is generated through a step generator unit followed by an integrator circuit and is applied to the camera's deflecting plates. The slope of the ramp can be changed by varying values of the capacitor and inductor. A programmable digital delay generator has been developed for synchronization of ramp signal with the optical signal. An independent hardwired interlock circuit has been developed for machine safety. A LABVIEW based graphical user interface has been developed which enables the user to program the settings of the camera and capture the image. The image is displayed with intensity profiles along horizontal and vertical axes. The streak camera was calibrated using nanosecond and femtosecond lasers.

  12. STREAK CAMERA MEASUREMENTS OF THE APS PC GUN DRIVE LASER

    Energy Technology Data Exchange (ETDEWEB)

    Dooling, J. C.; Lumpkin, A. H.

    2017-06-25

    We report recent pulse-duration measurements of the APS PC Gun drive laser at both second harmonic and fourth harmonic wavelengths. The drive laser is a Nd:Glass-based chirped pulsed amplifier (CPA) operating at an IR wavelength of 1053 nm, twice frequency-doubled to obtain UV output for the gun. A Hamamatsu C5680 streak camera and an M5675 synchroscan unit are used for these measurements; the synchroscan unit is tuned to 119 MHz, the 24th subharmonic of the linac s-band operating frequency. Calibration is accomplished both electronically and optically. Electronic calibration utilizes a programmable delay line in the 119 MHz rf path. The optical delay uses an etalon with known spacing between reflecting surfaces and is coated for the visible, SH wavelength. IR pulse duration is monitored with an autocorrelator. Fitting the streak camera image projected profiles with Gaussians, UV rms pulse durations are found to vary from 2.1 ps to 3.5 ps as the IR varies from 2.2 ps to 5.2 ps.

  13. Review of concepts and applications of image sampling on high-speed streak cameras

    Science.gov (United States)

    Shiraga, H.

    2017-02-01

    Image sampling is a simple, convenient and working scheme to obtain two-dimensional (2D) images on high-speed streak cameras which have only one-dimensional (1D) slit cathode as an imaging sensor on a streak tube. 1D sampling of a 2D image in one direction was realized as Multi-Imaging X-ray Streak camera (MIXS) with a similar configuration to TV raster scan. 2D sampling of a 2D image was realized as 2-D Sampling Image X-ray Streak camera (2D-SIXS) with a similar configuration to CCD pixels. For optical-UV streak cameras, 2D fiber plate coupled to the output of a streak camera was untied and fibers were rearranged to form a line on the cathode slit. In these schemes, clever arrangement of the sampling lines or points relative to the streaking direction were essential for avoiding overlap of the streaked signals with each other. These streak cameras with image sampling technique were successfully applied to laser plasma experiment, particularly for laser-driven nuclear fusion research with simultaneous temporal- and spatial resolutions of 10 ps and 15 μm, respectively. This paper reviews the concept, history, and such applications of the scheme.

  14. Standard design for National Ignition Facility x-ray streak and framing cameras

    Energy Technology Data Exchange (ETDEWEB)

    Kimbrough, J. R.; Bell, P. M.; Bradley, D. K.; Holder, J. P.; Kalantar, D. K.; MacPhee, A. G.; Telford, S.

    2010-10-01

    The x-ray streak camera and x-ray framing camera for the National Ignition Facility were redesigned to improve electromagnetic pulse hardening, protect high voltage circuits from pressure transients, and maximize the use of common parts and operational software. Both instruments use the same PC104 based controller, interface, power supply, charge coupled device camera, protective hermetically sealed housing, and mechanical interfaces. Communication is over fiber optics with identical facility hardware for both instruments. Each has three triggers that can be either fiber optic or coax. High voltage protection consists of a vacuum sensor to enable the high voltage and pulsed microchannel plate phosphor voltage. In the streak camera, the high voltage is removed after the sweep. Both rely on the hardened aluminum box and a custom power supply to reduce electromagnetic pulse/electromagnetic interference (EMP/EMI) getting into the electronics. In addition, the streak camera has an EMP/EMI shield enclosing the front of the streak tube.

  15. Optical Transmission Line For Streak Camera Measurements at Pitz

    CERN Document Server

    Bähr, J; Lüdecke, H

    2003-01-01

    The photoinjector injector test facility at DESY Zeuthen (PITZ) [1] produces electrons with a momentum of about 4 MeV/c. It is the aim to measure the temporal characteristics of the electron bunch train and single bunches with high accuracy of the order of 1 ps and less. Several types of streak cameras will be used in combination with different radiators which transform particle energy in light. The problem to be solved is the light transport over a distance of about 27 m. Basic demands to the optical system and design principles will be explained. The optical and technical solutions will be presented. The strategy of adjustment and commissioning of the optical system will be described. The system contains switchable optics to use different radiators (OTR, Cherenkov radiators). Diagnostic tools are foreseen at different positions along the optical axis. The results of different measurements in the lab and using the original system will be presented. The problems on the minimalization of the time dipersion in ...

  16. Structured photocathodes for improved high-energy x-ray efficiency in streak cameras

    Energy Technology Data Exchange (ETDEWEB)

    Opachich, Y. P., E-mail: opachiyp@nv.doe.gov; Huffman, E.; Koch, J. A. [National Security Technologies, LLC, Livermore, California 94551 (United States); Bell, P. M.; Bradley, D. K.; Hatch, B.; Landen, O. L.; MacPhee, A. G.; Nagel, S. R. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Chen, N.; Gopal, A.; Udin, S. [Nanoshift LLC, Emeryville, California 94608 (United States); Feng, J. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Hilsabeck, T. J. [General Atomics, San Diego, California 92121 (United States)

    2016-11-15

    We have designed and fabricated a structured streak camera photocathode to provide enhanced efficiency for high energy X-rays (1–12 keV). This gold coated photocathode was tested in a streak camera and compared side by side against a conventional flat thin film photocathode. Results show that the measured electron yield enhancement at energies ranging from 1 to 10 keV scales well with predictions, and that the total enhancement can be more than 3×. The spatial resolution of the streak camera does not show degradation in the structured region. We predict that the temporal resolution of the detector will also not be affected as it is currently dominated by the slit width. This demonstration with Au motivates exploration of comparable enhancements with CsI and may revolutionize X-ray streak camera photocathode design.

  17. Laser-based terahertz-field-driven streak camera for the temporal characterization of ultrashort processes

    Energy Technology Data Exchange (ETDEWEB)

    Schuette, Bernd

    2011-09-15

    In this work, a novel laser-based terahertz-field-driven streak camera is presented. It allows for a pulse length characterization of femtosecond (fs) extreme ultraviolet (XUV) pulses by a cross-correlation with terahertz (THz) pulses generated with a Ti:sapphire laser. The XUV pulses are emitted by a source of high-order harmonic generation (HHG) in which an intense near-infrared (NIR) fs laser pulse is focused into a gaseous medium. The design and characterization of a high-intensity THz source needed for the streak camera is also part of this thesis. The source is based on optical rectification of the same NIR laser pulse in a lithium niobate crystal. For this purpose, the pulse front of the NIR beam is tilted via a diffraction grating to achieve velocity matching between NIR and THz beams within the crystal. For the temporal characterization of the XUV pulses, both HHG and THz beams are focused onto a gas target. The harmonic radiation creates photoelectron wavepackets which are then accelerated by the THz field depending on its phase at the time of ionization. This principle adopted from a conventional streak camera and now widely used in attosecond metrology. The streak camera presented here is an advancement of a terahertz-field-driven streak camera implemented at the Free Electron Laser in Hamburg (FLASH). The advantages of the laser-based streak camera lie in its compactness, cost efficiency and accessibility, while providing the same good quality of measurements as obtained at FLASH. In addition, its flexibility allows for a systematic investigation of streaked Auger spectra which is presented in this thesis. With its fs time resolution, the terahertz-field-driven streak camera thereby bridges the gap between attosecond and conventional cameras. (orig.)

  18. Absolute calibration of optical streak cameras on picosecond time scales using supercontinuum generation.

    Science.gov (United States)

    Patankar, S; Gumbrell, E T; Robinson, T S; Floyd, E; Stuart, N H; Moore, A S; Skidmore, J W; Smith, R A

    2017-08-20

    We report a new method using high-stability, laser-driven supercontinuum generation in a liquid cell to calibrate the absolute photon response of fast optical streak cameras as a function of wavelength when operating at fastest sweep speeds. A stable, pulsed white light source based around the use of self-phase modulation in a salt solution was developed to provide the required brightness on picosecond time scales, enabling streak camera calibration in fully dynamic operation. The measured spectral brightness allowed for absolute photon response calibration over a broad spectral range (425-650 nm). Calibrations performed with two Axis Photonique streak cameras using the Photonis P820PSU streak tube demonstrated responses that qualitatively follow the photocathode response. Peak sensitivities were one photon/count above background. The absolute dynamic sensitivity is less than the static by up to an order of magnitude. We attribute this to the dynamic response of the phosphor being lower.

  19. Split ring resonator based THz-driven electron streak camera featuring femtosecond resolution.

    Science.gov (United States)

    Fabiańska, Justyna; Kassier, Günther; Feurer, Thomas

    2014-07-10

    Through combined three-dimensional electromagnetic and particle tracking simulations we demonstrate a THz driven electron streak camera featuring a temporal resolution on the order of a femtosecond. The ultrafast streaking field is generated in a resonant THz sub-wavelength antenna which is illuminated by an intense single-cycle THz pulse. Since electron bunches and THz pulses are generated with parts of the same laser system, synchronization between the two is inherently guaranteed.

  20. Robust reconstruction of time-resolved diffraction from ultrafast streak cameras

    Directory of Open Access Journals (Sweden)

    Daniel S. Badali

    2017-09-01

    Full Text Available In conjunction with ultrafast diffraction, streak cameras offer an unprecedented opportunity for recording an entire molecular movie with a single probe pulse. This is an attractive alternative to conventional pump-probe experiments and opens the door to studying irreversible dynamics. However, due to the “smearing” of the diffraction pattern across the detector, the streaking technique has thus far been limited to simple mono-crystalline samples and extreme care has been taken to avoid overlapping diffraction spots. In this article, this limitation is addressed by developing a general theory of streaking of time-dependent diffraction patterns. Understanding the underlying physics of this process leads to the development of an algorithm based on Bayesian analysis to reconstruct the time evolution of the two-dimensional diffraction pattern from a single streaked image. It is demonstrated that this approach works on diffraction peaks that overlap when streaked, which not only removes the necessity of carefully choosing the streaking direction but also extends the streaking technique to be able to study polycrystalline samples and materials with complex crystalline structures. Furthermore, it is shown that the conventional analysis of streaked diffraction can lead to erroneous interpretations of the data.

  1. The ELETTRA Streak Camera System Set-Up and First Results

    CERN Document Server

    Ferianis, M

    2000-01-01

    At ELETTRA, a Streak Camera system has been installed and tested. The bunch length is a significant machine parameter to measure, as it allows a direct derivation of fundamental machine characteristics, like its broadband impedance. At ELETTRA the Light from a Storage Ring Dipole is delivered through an optical system to an Optical Laboratory where it can be observed and analysed. The Streak Camera is equipped with different timebases, allowing both single sweep and dual sweep operation modes, including the Synchroscan mode. The Synchroscan frequency equal to 250 MHz, which is half of the ELETTRA RF frequency, allows the acquisition of consecutive bunches, 2ns apart. To fully exploit the performances of the Streak Camera, an optical path has been arranged which includes a fast opto-electronic shutter. By doing so, the optical power deposited on the photo-cathode is reduced in the different ELETTRA fillings.

  2. A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Jun; Engelhorn, K.; Cho, B.I.; Lee, H.J.; Greaves, M.; Weber, C.P.; Falcone, R.W.; Padmore, H. A.; Heimann, P.A.

    2010-02-18

    An ultrafast x-ray streak camera has been realized using a grazing incidence reflection photocathode. X-rays are incident on a gold photocathode at a grazing angle of 20 degree and photoemitted electrons are focused by a large aperture magnetic solenoid lens. The streak camera has high quantum efficiency, 600fs temporal resolution, and 6mm imaging length in the spectral direction. Its single shot capability eliminates temporal smearing due to sweep jitter, and allows recording of the ultrafast dynamics of samples that undergo non-reversible changes.

  3. Performance of Laser Megajoule’s x-ray streak camera

    Energy Technology Data Exchange (ETDEWEB)

    Zuber, C., E-mail: celine.zuber@cea.fr; Bazzoli, S.; Brunel, P.; Burillo, M.; Gontier, D.; Moreau, I.; Oudot, G.; Rubbelynck, C.; Soullié, G.; Stemmler, P.; Trosseille, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Fronty, J. P.; Goulmy, C. [Photonis France SAS, Avenue Roger Roncier, BP 520, 19106 Brive Cedex (France)

    2016-11-15

    A prototype of a picosecond x-ray streak camera has been developed and tested by Commissariat à l’Énergie Atomique et aux Énergies Alternatives to provide plasma-diagnostic support for the Laser Megajoule. We report on the measured performance of this streak camera, which almost fulfills the requirements: 50-μm spatial resolution over a 15-mm field in the photocathode plane, 17-ps temporal resolution in a 2-ns timebase, a detection threshold lower than 625 nJ/cm{sup 2} in the 0.05–15 keV spectral range, and a dynamic range greater than 100.

  4. Impact of laser phase and amplitude noises on streak camera temporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Wlotzko, V., E-mail: wlotzko@optronis.com [ICube, UMR 7357, University of Strasbourg and CNRS, 23 rue du Loess, 67037 Strasbourg (France); Optronis GmbH, Ludwigstrasse 2, 77694 Kehl (Germany); Uhring, W. [ICube, UMR 7357, University of Strasbourg and CNRS, 23 rue du Loess, 67037 Strasbourg (France); Summ, P. [Optronis GmbH, Ludwigstrasse 2, 77694 Kehl (Germany)

    2015-09-15

    Streak cameras are now reaching sub-picosecond temporal resolution. In cumulative acquisition mode, this resolution does not entirely rely on the electronic or the vacuum tube performances but also on the light source characteristics. The light source, usually an actively mode-locked laser, is affected by phase and amplitude noises. In this paper, the theoretical effects of such noises on the synchronization of the streak system are studied in synchroscan and triggered modes. More precisely, the contribution of band-pass filters, delays, and time walk is ascertained. Methods to compute the resulting synchronization jitter are depicted. The results are verified by measurement with a streak camera combined with a Ti:Al{sub 2}O{sub 3} solid state laser oscillator and also a fiber oscillator.

  5. Mach-zehnder based optical marker/comb generator for streak camera calibration

    Science.gov (United States)

    Miller, Edward Kirk

    2015-03-03

    This disclosure is directed to a method and apparatus for generating marker and comb indicia in an optical environment using a Mach-Zehnder (M-Z) modulator. High speed recording devices are configured to record image or other data defining a high speed event. To calibrate and establish time reference, the markers or combs are indicia which serve as timing pulses (markers) or a constant-frequency train of optical pulses (comb) to be imaged on a streak camera for accurate time based calibration and time reference. The system includes a camera, an optic signal generator which provides an optic signal to an M-Z modulator and biasing and modulation signal generators configured to provide input to the M-Z modulator. An optical reference signal is provided to the M-Z modulator. The M-Z modulator modulates the reference signal to a higher frequency optical signal which is output through a fiber coupled link to the streak camera.

  6. Development of intelligent control system for X-ray streak camera in diagnostic instrument manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Chengquan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China); Wu, Shengli, E-mail: slwu@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China); Tian, Jinshou [Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); Liu, Zhen [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China); Fang, Yuman [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China); University of the Chinese Academy of Sciences, Beijing 100039 (China); Gao, Guilong; Liang, Lingliang [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China); Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); University of the Chinese Academy of Sciences, Beijing 100039 (China); Wen, Wenlong [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China)

    2015-11-01

    An intelligent control system for an X ray streak camera in a diagnostic instrument manipulator (DIM) is proposed and implemented, which can control time delay, electric focusing, image gain adjustment, switch of sweep voltage, acquiring environment parameters etc. The system consists of 16 A/D converters and 16 D/A converters, a 32-channel general purpose input/output (GPIO) and two sensors. An isolated DC/DC converter with multi-outputs and a single mode fiber were adopted to reduce the interference generated by the common ground among the A/D, D/A and I/O. The software was designed using graphical programming language and can remotely access the corresponding instrument from a website. The entire intelligent control system can acquire the desirable data at a speed of 30 Mb/s and store it for later analysis. The intelligent system was implemented on a streak camera in a DIM and it shows a temporal resolution of 11.25 ps, spatial distortion of less than 10% and dynamic range of 279:1. The intelligent control system has been successfully used in a streak camera to verify the synchronization of multi-channel laser on the Inertial Confinement Fusion Facility.

  7. Electronic Image Readout Devices Used In Conjunction With Picosecond Streak Cameras

    Science.gov (United States)

    Cavailler, C.; Genoud, M.; Fleurot, N.; Launspach, J.; Mazataud, D.; Mens, A.

    1985-02-01

    Understanding the laser-matter interaction experiments require a dynamic recording of the phenomena as well as a good knowledge of the laser pulse occuring during the irradiation of the target ; those measurements are made with streak cameras the increasing number of which leads to processing problems when the results are recorded on films. Furthermore, since physicists wish to have those temporal information immediatly, we unfolded automatic image readout devices fitted specially to streak cameras. The first one used an ISOCON tube operating with a slow sweep (0.5 s frame)1-2. The sensitivity of the tube was very good but its dynamic range was too limited when seeing pulsed images at low light level. So we developped two electronic readout chains with solid state devices which behave better for that kind of light. The first one was designed to get the most information along the temporal axis of the camera sweep (1024 points) in one or two spatial channels ; this device operates a linear 1024 photodiodes array the signal of which is digitized on 12 bits. We have obtained a temporal resolution better than 15 ps and a dynamic range over 500 ; this system is mainly useful to study laser pulses (rise time, temporal profile...)3. For applications requiring two dimension images, we studied and realized a device operating a CCD array and a fiber optics reducer (40-18 mm) adapting the image of the streak camera screen to the dimensions of the input fiber optics of the CCD. A comparison has been made on different CCD cameras on a test setup which simulates the experimental conditions, in order to choose the CCD which would fit the best for that purpose ; we present these results here, as well as those of the associated readout chains.

  8. Improving the off-axis spatial resolution and dynamic range of the NIF X-ray streak cameras (invited).

    Science.gov (United States)

    MacPhee, A G; Dymoke-Bradshaw, A K L; Hares, J D; Hassett, J; Hatch, B W; Meadowcroft, A L; Bell, P M; Bradley, D K; Datte, P S; Landen, O L; Palmer, N E; Piston, K W; Rekow, V V; Hilsabeck, T J; Kilkenny, J D

    2016-11-01

    We report simulations and experiments that demonstrate an increase in spatial resolution of the NIF core diagnostic x-ray streak cameras by at least a factor of two, especially off axis. A design was achieved by using a corrector electron optic to flatten the field curvature at the detector plane and corroborated by measurement. In addition, particle in cell simulations were performed to identify the regions in the streak camera that contribute the most to space charge blurring. These simulations provide a tool for convolving synthetic pre-shot spectra with the instrument function so signal levels can be set to maximize dynamic range for the relevant part of the streak record.

  9. Improving the off-axis spatial resolution and dynamic range of the NIF X-ray streak cameras (invited)

    Science.gov (United States)

    MacPhee, A. G.; Dymoke-Bradshaw, A. K. L.; Hares, J. D.; Hassett, J.; Hatch, B. W.; Meadowcroft, A. L.; Bell, P. M.; Bradley, D. K.; Datte, P. S.; Landen, O. L.; Palmer, N. E.; Piston, K. W.; Rekow, V. V.; Hilsabeck, T. J.; Kilkenny, J. D.

    2016-11-01

    We report simulations and experiments that demonstrate an increase in spatial resolution of the NIF core diagnostic x-ray streak cameras by at least a factor of two, especially off axis. A design was achieved by using a corrector electron optic to flatten the field curvature at the detector plane and corroborated by measurement. In addition, particle in cell simulations were performed to identify the regions in the streak camera that contribute the most to space charge blurring. These simulations provide a tool for convolving synthetic pre-shot spectra with the instrument function so signal levels can be set to maximize dynamic range for the relevant part of the streak record.

  10. Temporal Characterization of Electron Beam Bunches with a Fast Streak Camera at the JLab FEL Facility

    CERN Document Server

    Zhang, S; Douglas, D; Hardy, D; Hernandez-Garcia, C; Jordan, K; Neil, G; Shinn, M D

    2005-01-01

    The design and construction of an optical transport that brings synchrotron radiation from electron bunches to a fast streak camera in a remote area has become a useful tool for online observation of bunch length and stability. This paper will report on the temporal measurements we have done, comparison with simulations, and the on-going work for another imaging optical transport system that will make possible the direct measurement of the longitudinal phase space by measuring the bunch length as a function of energy.

  11. Applications of a streak-camera-based imager with simultaneous high space and time resolution

    Science.gov (United States)

    Klick, David I.; Knight, Frederick K.

    1993-01-01

    A high-speed imaging device has been built that is capable of recording several hundred images over a time span of 25 to 400 ns. The imager is based on a streak camera, which provides both spatial and temporal resolution. The system's current angular resolution is 16 X 16 pixels, with a time resolution of 250 ps. It was initially employed to provide 3-D images of objects, in conjunction with a short-pulse (approximately 100 ps) laser. For the 3-D (angle-angle-range) laser radar, the 250 ps time resolution corresponds to a range resolution of 4 cm. In the 3-D system, light from a short-pulse laser (a frequency-doubled, Q-switched, mode-locked Nd:YAG laser operating at a wavelength of 532 nm) flood-illuminates a target of linear dimension approximately 1 m. The returning light from the target is imaged, and the image is dissected by a 16 X 16 array of optical fibers. At the other end of the fiber optic image converter, the 256 fibers form a vertical line array, which is input to the slit of a streak camera. The streak camera sweeps the input line across the output phosphor screen so that horizontal position is directly proportional to time. The resulting 2-D image (fiber location vs. time) at the phosphor is read by an intensified (SIT) vidicon TV tube, and the image is digitized and stored. A computer subsequently decodes the image, unscrambling the linear pixels into an angle-angle image at each time or range bin. We are left with a series of snapshots, each one depicting the portion of target surface in a given range bin. The pictures can be combined to form a 3-D realization of the target. Continuous recording of many images over a short time span is of use in imaging other transient phenomena. These applications share a need for multiple images from a nonrepeatable transient event of time duration on the order of nanoseconds. Applications discussed for the imager include (1) pulsed laser beam diagnostics -- measuring laser beam spatial and temporal structure, (2

  12. A Robust In-Situ Warp-Correction Algorithm For VISAR Streak Camera Data at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Labaria, George R. [Univ. of California, Santa Cruz, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Warrick, Abbie L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Celliers, Peter M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kalantar, Daniel H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-01-12

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a 192-beam pulsed laser system for high-energy-density physics experiments. Sophisticated diagnostics have been designed around key performance metrics to achieve ignition. The Velocity Interferometer System for Any Reflector (VISAR) is the primary diagnostic for measuring the timing of shocks induced into an ignition capsule. The VISAR system utilizes three streak cameras; these streak cameras are inherently nonlinear and require warp corrections to remove these nonlinear effects. A detailed calibration procedure has been developed with National Security Technologies (NSTec) and applied to the camera correction analysis in production. However, the camera nonlinearities drift over time, affecting the performance of this method. An in-situ fiber array is used to inject a comb of pulses to generate a calibration correction in order to meet the timing accuracy requirements of VISAR. We develop a robust algorithm for the analysis of the comb calibration images to generate the warp correction that is then applied to the data images. Our algorithm utilizes the method of thin-plate splines (TPS) to model the complex nonlinear distortions in the streak camera data. In this paper, we focus on the theory and implementation of the TPS warp-correction algorithm for the use in a production environment.

  13. Overall comparison of subpicosecond electron beam diagnostics by the polychromator, the interferometer and the femtosecond streak camera

    CERN Document Server

    Watanabe, T; Yoshimatsu, T; Sasaki, S; Sugiyama, Y; Ishi, K; Shibata, Y; Kondo, Y; Yoshii, K; Ueda, T; Uesaka, M

    2002-01-01

    Measurements of longitudinal bunch length of subpicosecond and picosecond electron beams have been performed by three methods with three radiation sources at the 35 MeV S-band twin liner accelerators at Nuclear Engineering Research Laboratory, University of Tokyo. The methods we adopt are the femtosecond streak camera with a nondispersive reflective optics, the coherent transition radiation (CTR) Michelson interferometer and the 10 ch polychromator that detects the spectrum of CTR and coherent diffraction radiation (CDR). The measurements by the two CTR methods were independently done with the streak camera and their results were consistent with one another. As a result, the reliability of the polychromator for the diagnostics of less than picosecond electron bunch and the usefulness of the diagnostics for the single shot measurement were verified. Furthermore, perfect nondestructive diagnostics for subpicosecond bunches was performed utilizing CDR interferometry. Then the good agreement between CDR interfero...

  14. Fluorescence measurement by a streak camera in a single-photon-counting mode.

    Science.gov (United States)

    Komura, Masayuki; Itoh, Shigeru

    2009-01-01

    We describe here a recently developed fluorescence measurement system that uses a streak camera to detect fluorescence decay in a single photon-counting mode. This system allows for easy measurements of various samples and provides 2D images of fluorescence in the wavelength and time domains. The great advantage of the system is that the data can be handled with ease; furthermore, the data are amenable to detailed analysis. We describe the picosecond kinetics of fluorescence in spinach Photosystem (PS) II particles at 4-77 K as a typical experimental example. Through the global analysis of the data, we have identified a new fluorescence band (F689) in addition to the already established F680, F685, and F695 emission bands. The blue shift of the steady-state fluorescence spectrum upon cooling below 77 K can be interpreted as an increase of the shorter-wavelength fluorescence, especially F689, due to the slowdown of the excitation energy transfer process. The F685 and F695 bands seem to be thermally equilibrated at 77 K but not at 4 K. The simple and efficient photon accumulation feature of the system allows us to measure fluorescence from leaves, solutions, single colonies, and even single cells. The 2D fluorescence images obtained by this system are presented for isolated spinach PS II particles, intact leaves of Arabidopsis thaliana, the PS I super-complex of a marine centric diatom, Chaetoceros gracilis, isolated membranes of a purple photosynthetic bacterium, Acidiphilium rubrum, which contains Zn-BChl a, and a coral that contains a green fluorescent protein and an algal endosymbiont, Zooxanthella.

  15. Time and wavelength-resolved luminescence evaluation of several types of scintillators using streak camera system equipped with pulsed X-ray source

    Czech Academy of Sciences Publication Activity Database

    Furuya, Y.; Yanagida, T.; Fujimoto, Y.; Yokota, Y.; Kamada, K.; Kawaguchi, N.; Ishizu, S.; Uchiyama, K.; Mori, K.; Kitano, K.; Nikl, Martin; Yoshikawa, A.

    2011-01-01

    Roč. 634, č. 1 (2011), s. 59-63 ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10100521 Keywords : streak camera system * scintillator * pulsed X-ray source Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.207, year: 2011

  16. Streak Camera Studies of Vertical Synchro-Betatron-Coupled Electron Beam Motion in the APS Storage Ring

    CERN Document Server

    Yang Bing Xin; Guo, Weiming; Harkay, Katherine C; Sajaev, Vadim

    2005-01-01

    We present experimental studies of synchro-betatron-coupled electron beam motion in the Advanced Photon Source storage ring. We used a vertical kicker to start the beam motion. When the vertical chromaticity is nonzero, electrons with different initial synchrotron phases have slightly different betatron frequencies from the synchronous particle, resulting in a dramatic progression of bunch-shape distortion. Depending on the chromaticity and the time following the kick, images ranging from a simple vertical tilt in the bunch to more complicated twists and bends are seen with a visible light streak camera. Turn-by-turn beam position monitor data were taken as well. We found that the experimental observations are well described by the synchro-betatron-coupled equations of motion. We are investigating the potential of using the tilted bunch to generate picosecond x-ray pulses. Also note that the fast increase in vertical beam size after the kick is dominated by the internal synchro-betatron-coupled motion of the ...

  17. Evaluation of dynamic range for LLNL streak cameras using high contrast pulses and pulse podiatry'' on the Nova laser system

    Energy Technology Data Exchange (ETDEWEB)

    Richards, J.B.; Weiland, T.L.; Prior, J.A.

    1990-07-01

    A standard LLNL streak camera has been used to analyze high contrast pulses on the Nova laser facility. These pulses have a plateau at their leading edge (foot) with an amplitude which is approximately 1% of the maximum pulse height. Relying on other features of the pulses and on signal multiplexing, we were able to determine how accurately the foot amplitude was being represented by the camera. Results indicate that the useful single channel dynamic range of the instrument approaches 100:1. 1 ref., 4 figs., 1 tab.

  18. Neutron streak camera

    Science.gov (United States)

    Wang, Ching L.

    1983-09-13

    Apparatus for improved sensitivity and time resolution of a neutron measurement. The detector is provided with an electrode assembly having a neutron sensitive cathode which emits relatively low energy secondary electrons. The neutron sensitive cathode has a large surface area which provides increased sensitivity by intercepting a greater number of neutrons. The cathode is also curved to compensate for differences in transit time of the neutrons emanating from the point source. The slower speeds of the secondary electrons emitted from a certain portion of the cathode are matched to the transit times of the neutrons impinging thereupon.

  19. Potential applications of a dual-sweep streak camera system for characterizing particle and photon beams of VUV, XUV, and x-ray FELS

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. [Argonne National Lab., IL (United States)

    1995-12-31

    The success of time-resolved imaging techniques in the Characterization of particle beams and photon beams of the recent generation of L-band linac-driven or storage ring FELs in the infrared, visible, and ultraviolet wavelength regions can be extended to the VUV, XUV, and x-ray FELs. Tests and initial data have been obtained with the Hamamatsu C5680 dual-sweep streak camera system which includes a demountable photocathode (thin Au) assembly and a flange that allows windowless operation with the transport vacuum system. This system can be employed at wavelengths shorter than 100 nm and down to 1 {Angstrom}. First tests on such a system at 248-nm wavelengths have been performed oil the Argonne Wakefield Accelerator (AWA) drive laser source. A quartz window was used at the tube entrance aperture. A preliminary test using a Be window mounted on a different front flange of the streak tube to look at an x-ray bremsstrahlung source at the AWA was limited by photon statistics. This system`s limiting resolution of {sigma}{approximately}1.1 ps observed at 248 nm would increase with higher incoming photon energies to the photocathode. This effect is related to the fundamental spread in energies of the photoelectrons released from the photocathodes. Possible uses of the synchrotron radiation sources at the Advanced Photon Source and emerging short wavelength FELs to test the system will be presented.

  20. Proximity focusing RICH detector based on multilayer silica aerogel radiator

    CERN Document Server

    De Leo, R; Bellunato, T; Calvi, M; Cisbani, E; Cusanno, F; Garibaldi, F; Lagamba, L; Marra, M; Marrone, S; Matteuzzi, C; Musico, P; Nappi, E; Perego, D L; Torrioli, S; Vilardi, I

    2010-01-01

    The performance of a proximity focusing Ring Imaging Cherenkov detector equipped with a radiator of silica aerogel is presented. The aerogel tile used is a monolith with variable index of refraction. Cherenkov photons are detected with high granularity by eight Hamamatsu H9500 flat panel multi anode phototubes.

  1. Light field driven streak-camera for single-shot measurements of the temporal profile of XUV-pulses from a free-electron laser; Lichtfeld getriebene Streak-Kamera zur Einzelschuss Zeitstrukturmessung der XUV-Pulse eines Freie-Elektronen Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Fruehling, Ulrike

    2009-10-15

    The Free Electron Laser in Hamburg (FLASH) is a source for highly intense ultra short extreme ultraviolet (XUV) light pulses with pulse durations of a few femtoseconds. Due to the stochastic nature of the light generation scheme based on self amplified spontaneous emission (SASE), the duration and temporal profile of the XUV pulses fluctuate from shot to shot. In this thesis, a THz-field driven streak-camera capable of single pulse measurements of the XUV pulse-profile has been realized. In a first XUV-THz pump-probe experiment at FLASH, the XUV-pulses are overlapped in a gas target with synchronized THz-pulses generated by a new THz-undulator. The electromagnetic field of the THz light accelerates photoelectrons produced by the XUV-pulses with the resulting change of the photoelectron momenta depending on the phase of the THz field at the time of ionisation. This technique is intensively used in attosecond metrology where near infrared streaking fields are employed for the temporal characterisation of attosecond XUV-Pulses. Here, it is adapted for the analysis of pulse durations in the few femtosecond range by choosing a hundred times longer far infrared streaking wavelengths. Thus, the gap between conventional streak cameras with typical resolutions of hundreds of femtoseconds and techniques with attosecond resolution is filled. Using the THz-streak camera, the time dependent electric field of the THz-pulses was sampled in great detail while on the other hand the duration and even details of the time structure of the XUV-pulses were characterized. (orig.)

  2. Generation of intense high harmonics: (i) To test and improve resolution of accumulative X-ray streak camera; (ii) To study the effects of Carrier envelope phase on XUV super continuum generation by polarization gating

    Science.gov (United States)

    Shakya, Mahendra Man

    The first part of this thesis describes our novel design, test, and application of our X-ray streak camera to the pulse duration measurement of soft X-rays. We demonstrated a significant improvement in the resolution of the x-ray streak camera by reducing the electron beam size in the deflection plates. This was accomplished by adding a slit in front of the focusing lens and the deflection plates. The temporal resolution reached 280 fs when the slit width was 5 mum. The camera was operated in an accumulative mode and tested by using a 25 fs laser with 2 kHz repetition rate and 1-2% RMS pulse energy stability. We conclude that deflection aberrations, which limit the resolution of the camera, can be appreciably reduced by eliminating the wide-angle electrons. We also employed the same streak camera to demonstrate that it is capable of measuring the pulse duration of X-rays. We measured the pulse duration of X-rays emitted from Ni-like Ag and Cd grazing-incidence laser to be ˜5ps. The measured value agrees with the prediction made by the model and the measurement made by changing the delay as a function of the pulse duration. The streak camera was also tested with various sources of X-ray such as high harmonics generation of soft x-rays from an argon atom using a high power Ti:sapphire laser source of KLS. The result of the measurement manifests its capability for serving as a detector in the study of ultrafast dynamics in the field of physics, chemistry, biology and medical sciences. The second part of this thesis describes our design of a spectrometer to study the effect of the Carrier envelope (CE) phase on polarization gated extreme-ultraviolet (XUV) super-continuum generation. Because the challenge of making single shot experiment possible is to generate a sufficient number of photons, our setup has been built to allow generation of high order harmonics at the maximum phase matched pressure. This is the first time to our knowledge that phase matching in the

  3. Planetary-scale streak structures produced in a high-resolution simulation of Venus atmosphere

    Science.gov (United States)

    Kashimura, H.; Sugimoto, N.; Takagi, M.; Matsuda, Y.; Ohfuchi, W.; Enomoto, T.; Nakajima, K.; Ishiwatari, M.; Sato, T. M.; Hashimoto, G. L.; Satoh, T.; Takahashi, Y. O.; Hayashi, Y.-Y.

    2017-09-01

    Planetary-scale streak structures captured by the IR2 camera onboard AKATSUKI was reproduced in a high-resolution simulation of Venus Atmosphere. We have found that the streak structures are extending from the polar vortices and synchronized in both hemispheres. Our experiments suggest that a low-stability layer is a key for forming the planetary-scale streak structures.

  4. Use of proximity focused HPDs for the inner trigger detector of the FINUDA experiment

    CERN Document Server

    Marchesotti, M

    2000-01-01

    A barrel scintillator detector viewed by proximity focused HPDs will be employed in the inner region of the FINUDA experiment inside a 1.1 T magnetic field to provide a fast first level trigger, the common stop for drift chambers and straw tubes and the start signal for Time-of-Flight (ToF) measurements. The overall performances have been tested with a laser system and sup 9 sup 0 Sr radiation source.

  5. Streak Camera for Strong-Field Ionization

    Science.gov (United States)

    Kübel, M.; Dube, Z.; Naumov, A. Yu.; Spanner, M.; Paulus, G. G.; Kling, M. F.; Villeneuve, D. M.; Corkum, P. B.; Staudte, A.

    2017-11-01

    Ionization of an atom or molecule by a strong laser field produces suboptical cycle wave packets whose control has given rise to attosecond science. The final states of the wave packets depend on ionization and deflection by the laser field, which are convoluted in conventional experiments. Here, we demonstrate a technique enabling efficient electron deflection, separate from the field driving strong-field ionization. Using a midinfrared deflection field permits one to distinguish electron wave packets generated at different field maxima of an intense few-cycle visible laser pulse. We utilize this capability to trace the scattering of low-energy electrons driven by the midinfrared field. Our approach represents a general technique for studying and controlling strong-field ionization dynamics on the attosecond time scale.

  6. A proximity focusing RICH detector for kaon physics at Jefferson lab hall A

    CERN Document Server

    Garibaldi, F; Colilli, S; Cusanno, F; Frullani, S; Fratoni, R; Giuliani, F; Gricia, M; Iodice, M; Lucentini, M; Pierangeli, L; Santavenere, F; Urciuoli, G M; Veneroni, P; De Cataldo, G

    2003-01-01

    Important information on the LambdaN interaction can be obtained from High Resolution Hypenuclear Spectroscopy experiments with electromagnetic probes. A challenging experiment on electroproduction of hypernuclei is scheduled for 2003 in Hall A at Jefferson Lab. One of the challenges is the high performance particle identification system needed. The signal is expected to be rare compared to the very high pion and proton backgrounds due to the small electron and kaon detection angles. The "standard" Hall A PID apparatus (TOF and two aerogel threshold Cherenkov detectors) does not provide sufficient suppression of the background. Simulations and calculations have shown that a RICH detector would solve the problem. A proximity focusing fluorocarbon/CsI detector similar to the ALICE RICH detector has been designed, built, tested and commissioned. The results show that the detector performs as expected.

  7. Simulation of FEL pulse length calculation with THz streaking method

    Energy Technology Data Exchange (ETDEWEB)

    Gorgisyan, I., E-mail: ishkhan.gorgisyan@psi.ch [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); École Polytechnique Fédérale de Lausanne, Route Cantonale, 1015 Lausanne (Switzerland); Ischebeck, R.; Prat, E.; Reiche, S. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Rivkin, L. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); École Polytechnique Fédérale de Lausanne, Route Cantonale, 1015 Lausanne (Switzerland); Juranić, P., E-mail: ishkhan.gorgisyan@psi.ch [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

    2016-04-02

    Simulation of THz streaking of photoelectrons created by X-ray pulses from a free-electron laser and reconstruction of the free-electron laser pulse lengths. Having accurate and comprehensive photon diagnostics for the X-ray pulses delivered by free-electron laser (FEL) facilities is of utmost importance. Along with various parameters of the photon beam (such as photon energy, beam intensity, etc.), the pulse length measurements are particularly useful both for the machine operators to measure the beam parameters and monitor the stability of the machine performance, and for the users carrying out pump–probe experiments at such facilities to better understand their measurement results. One of the most promising pulse length measurement techniques used for photon diagnostics is the THz streak camera which is capable of simultaneously measuring the lengths of the photon pulses and their arrival times with respect to the pump laser. This work presents simulations of a THz streak camera performance. The simulation procedure utilizes FEL pulses with two different photon energies in hard and soft X-ray regions, respectively. It recreates the energy spectra of the photoelectrons produced by the photon pulses and streaks them by a single-cycle THz pulse. Following the pulse-retrieval procedure of the THz streak camera, the lengths were calculated from the streaked spectra. To validate the pulse length calculation procedure, the precision and the accuracy of the method were estimated for streaking configuration corresponding to previously performed experiments. The obtained results show that for the discussed setup the method is capable of measuring FEL pulses with about a femtosecond accuracy and precision.

  8. Streak image denoising and segmentation using adaptive Gaussian guided filter.

    Science.gov (United States)

    Jiang, Zhuocheng; Guo, Baoping

    2014-09-10

    In streak tube imaging lidar (STIL), streak images are obtained using a CCD camera. However, noise in the captured streak images can greatly affect the quality of reconstructed 3D contrast and range images. The greatest challenge for streak image denoising is reducing the noise while preserving details. In this paper, we propose an adaptive Gaussian guided filter (AGGF) for noise removal and detail enhancement of streak images. The proposed algorithm is based on a guided filter (GF) and part of an adaptive bilateral filter (ABF). In the AGGF, the details are enhanced by optimizing the offset parameter. AGGF-denoised streak images are significantly sharper than those denoised by the GF. Moreover, the AGGF is a fast linear time algorithm achieved by recursively implementing a Gaussian filter kernel. Experimentally, AGGF demonstrates its capacity to preserve edges and thin structures and outperforms the existing bilateral filter and domain transform filter in terms of both visual quality and peak signal-to-noise ratio performance.

  9. The theoretical simulation on electrostatic distribution of 1st proximity region in proximity focusing low-light-level image intensifier

    Science.gov (United States)

    Zhang, Liandong; Bai, Xiaofeng; Song, De; Fu, Shencheng; Li, Ye; Duanmu, Qingduo

    2015-03-01

    Low-light-level night vision technology is magnifying low light level signal large enough to be seen by naked eye, which uses the photons - photoelectron as information carrier. Until the micro-channel plate was invented, it has been possibility for the realization of high performance and miniaturization of low-light-level night vision device. The device is double-proximity focusing low-light-level image intensifier which places a micro-channel plate close to photocathode and phosphor screen. The advantages of proximity focusing low-light-level night vision are small size, light weight, small power consumption, no distortion, fast response speed, wide dynamic range and so on. It is placed parallel to each other for Micro-channel plate (both sides of it with metal electrode), the photocathode and the phosphor screen are placed parallel to each other. The voltage is applied between photocathode and the input of micro-channel plate when image intensifier works. The emission electron excited by photo on the photocathode move towards to micro-channel plate under the electric field in 1st proximity focusing region, and then it is multiplied through the micro-channel. The movement locus of emission electrons can be calculated and simulated when the distributions of electrostatic field equipotential lines are determined in the 1st proximity focusing region. Furthermore the resolution of image tube can be determined. However the distributions of electrostatic fields and equipotential lines are complex due to a lot of micro-channel existing in the micro channel plate. This paper simulates electrostatic distribution of 1st proximity region in double-proximity focusing low-light-level image intensifier with the finite element simulation analysis software Ansoft maxwell 3D. The electrostatic field distributions of 1st proximity region are compared when the micro-channel plates' pore size, spacing and inclination angle ranged. We believe that the electron beam movement

  10. HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY2nd QUARTER 2010 MILESTONE REPORTDevelop the theory connecting pyrometer and streak camera spectrometer data to the material properties of beam heatedtargets and compare to the data

    Energy Technology Data Exchange (ETDEWEB)

    More, R.M.; Barnard, J. J.; Bieniosek, F.M.; Henestroza, E.; Lidia, S. M.; Ni, P. A.

    2010-04-01

    This milestone has been accomplished. We have extended the theory that connects pyrometer and streak spectrometer data to material temperature on several fronts and have compared theory to NDCX-I experiments. For the case of NDCX-I, the data suggests that as the metallic foils are heated they break into droplets (cf. HIFS VNL Milestone Report FY 2009 Q4). Evaporation of the metallic surface will occur, but optical emission should be directly observable from the solid or liquid surface of the foil or from droplets. However, the emissivity of hot material may be changed from the cold material and interference effects will alter the spectrum emitted from small droplets. These effects have been incorporated into a theory of emission from droplets. We have measured emission using streaked spectrometry and together with theory of emission from heated droplets have inferred the temperature of a gold foil heated by the NDCX-I experiment. The intensity measured by the spectrometer is proportional to the emissivity times the blackbody intensity at the temperature of the foil or droplets. Traditionally, a functional form for the emissivity as a function of wavelength (such as a quadratic) is assumed and the three unknown emissivity parameters (for the case of a quadratic) and the temperature are obtained by minimizing the deviations from the fit. In the case of the NDCX-I experiment, two minima were obtained: at 7200 K and 2400 K. The best fit was at 7200 K. However, when the actual measured emissivity of gold was used and when the theoretical corrections for droplet interference effects were made for emission from droplets having radii in the range 0.2 to 2.0 microns, the corrected emissivity was consistent with the 2400 K value, whereas the fit emissivity at 7200 K shows no similarity to the corrected emissivity curves. Further, an estimate of the temperature obtained from beam heating is consistent with the lower value. This exercise proved to be a warning to be skeptical

  11. Streaking into middle school science: The Dell Streak pilot project

    Science.gov (United States)

    Austin, Susan Eudy

    A case study is conducted implementing the Dell Streak seven-inch android device into eighth grade science classes of one teacher in a rural middle school in the Piedmont region of North Carolina. The purpose of the study is to determine if the use of the Dell Streaks would increase student achievement on standardized subject testing, if the Streak could be used as an effective instructional tool, and if it could be considered an effective instructional resource for reviewing and preparing for the science assessments. A mixed method research design was used for the study to analyze both quantitative and qualitative results to determine if the Dell Streaks' utilization could achieve the following: 1. instructional strategies would change, 2. it would be an effective instructional tool, and 3. a comparison of the students' test scores and benchmark assessments' scores would provide statistically significant difference. Through the use of an ANOVA it was determined a statistically significant difference had occurred. A Post Hoc analysis was conducted to identify where the difference occurred. Finally a T-test determined was there was no statistically significance difference between the mean End-of-Grade tests and four quarterly benchmark scores of the control and the experimental groups. Qualitative research methods were used to gather results to determine if the Streaks were an effective instructional tool. Classroom observations identified that the teacher's teaching styles and new instructional strategies were implemented throughout the pilot project. Students had an opportunity to complete a questionnaire three times during the pilot project. Results revealed what the students liked about using the devices and the challenges they were facing. The teacher completed a reflective questionnaire throughout the pilot project and offered valuable reflections about the use of the devices in an educational setting. The reflection data supporting the case study was drawn

  12. Influence of the geometry of low-speed streak on the streak instability

    OpenAIRE

    浅井, 雅人; 嵯峨, 信一; 小西, 康郁; Masahito, ASAI; Shinichi, SAGA; Yasufumi, KONISHI; 都科技大; 都科技大; 都科技大; Dept. of Aerospace Eng., Tokyo Metropolitan Inst. of Tech.; Dept. of Aerospace Eng., Tokyo Metropolitan Inst. of Tech.; Dept. of Aerospace Eng., Tokyo Metropolitan Inst. of Tech.

    2001-01-01

    In order to examine the nature of streak instability experimentally, a single low-speed streak is produced by a small piece of screen set normal to the wall in a laminar boundary layer. The lateral width and height of the screen are varied systematically to see the dependency of the streak instability on the geometry of the streak. The results show that when the lateral width of the low-speed streak is greater than three or four times the shear-layer thickness, the streak instability to symme...

  13. Secondary threshold amplitudes for sinuous streak breakdown

    Science.gov (United States)

    Cossu, Carlo; Brandt, Luca; Bagheri, Shervin; Henningson, Dan S.

    2011-07-01

    The nonlinear stability of laminar sinuously bent streaks is studied for the plane Couette flow at Re = 500 in a nearly minimal box and for the Blasius boundary layer at Reδ*=700. The initial perturbations are nonlinearly saturated streamwise streaks of amplitude AU perturbed with sinuous perturbations of amplitude AW. The local boundary of the basin of attraction of the linearly stable laminar flow is computed by bisection and projected in the AU - AW plane providing a well defined critical curve. Different streak transition scenarios are seen to correspond to different regions of the critical curve. The modal instability of the streaks is responsible for transition for AU = 25%-27% for the considered flows, where sinuous perturbations of amplitude below AW ≈ 1%-2% are sufficient to counteract the streak viscous dissipation and induce breakdown. The critical amplitude of the sinuous perturbations increases when the streamwise streak amplitude is decreased. With secondary perturbations amplitude AW ≈ 4%, breakdown is induced on stable streamwise streaks with AU ≈ 13%, following the secondary transient growth scenario first examined by Schoppa and Hussain [J. Fluid Mech. 453, 57 (2002)]. A cross-over, where the critical amplitude of the sinuous perturbation becomes larger than the amplitude of streamwise streaks, is observed for streaks of small amplitude AU < 5%-6%. In this case, the transition is induced by an initial transient amplification of streamwise vortices, forced by the decaying sinuous mode. This is followed by the growth of the streaks and final breakdown. The shape of the critical AU - AW curve is very similar for Couette and boundary layer flows and seems to be relatively insensitive to the nature of the edge states on the basin boundary. The shape of this critical curve indicates that the stability of streamwise streaks should always be assessed in terms of both the streak amplitude and the amplitude of spanwise velocity perturbations.

  14. Nonlinear streak computation using boundary region equations

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J A; Martel, C, E-mail: juanangel.martin@upm.es, E-mail: carlos.martel@upm.es [Depto. de Fundamentos Matematicos, E.T.S.I Aeronauticos, Universidad Politecnica de Madrid, Plaza Cardenal Cisneros 3, 28040 Madrid (Spain)

    2012-08-01

    The boundary region equations (BREs) are applied for the simulation of the nonlinear evolution of a spanwise periodic array of streaks in a flat plate boundary layer. The well-known BRE formulation is obtained from the complete Navier-Stokes equations in the high Reynolds number limit, and provides the correct asymptotic description of three-dimensional boundary layer streaks. In this paper, a fast and robust streamwise marching scheme is introduced to perform their numerical integration. Typical streak computations present in the literature correspond to linear streaks or to small-amplitude nonlinear streaks computed using direct numerical simulation (DNS) or the nonlinear parabolized stability equations (PSEs). We use the BREs to numerically compute high-amplitude streaks, a method which requires much lower computational effort than DNS and does not have the consistency and convergence problems of the PSE. It is found that the flow configuration changes substantially as the amplitude of the streaks grows and the nonlinear effects come into play. The transversal motion (in the wall normal-streamwise plane) becomes more important and strongly distorts the streamwise velocity profiles, which end up being quite different from those of the linear case. We analyze in detail the resulting flow patterns for the nonlinearly saturated streaks and compare them with available experimental results. (paper)

  15. Time-resolved photoemission using attosecond streaking

    Science.gov (United States)

    Nagele, S.; Pazourek, R.; Wais, M.; Wachter, G.; Burgdörfer, J.

    2014-04-01

    We theoretically study time-resolved photoemission in atoms as probed by attosecond streaking. We review recent advances in the study of the photoelectric efect in the time domain and show that the experimentally accessible time shifts can be decomposed into distinct contributions that stem from the feld-free photoionization process itself and from probe-field induced corrections. We perform accurate quantum-mechanical as well as classical simulations of attosecond streaking for efective one-electron systems and determine all relevant contributions to the time delay with attosecond precision. In particular, we investigate the properties and limitations of attosecond streaking for the transition from short-ranged potentials (photodetachment) to long-ranged Coulomb potentials (photoionization). As an example for a more complex system, we study time-resolved photoionization for endohedral fullerenes A@C60 and discuss how streaking time shifts are modifed due to the interaction of the C60 cage with the probing infrared streaking field.

  16. Wind Streaks on Earth; Exploration and Interpretation

    Science.gov (United States)

    Cohen-Zada, Aviv Lee; Blumberg, Dan G.; Maman, Shimrit

    2015-04-01

    Wind streaks, one of the most common aeolian features on planetary surfaces, are observable on the surface of the planets Earth, Mars and Venus. Due to their reflectance properties, wind streaks are distinguishable from their surroundings, and they have thus been widely studied by remote sensing since the early 1970s, particularly on Mars. In imagery, these streaks are interpreted as the presence - or lack thereof - of small loose particles on the surface deposited or eroded by wind. The existence of wind streaks serves as evidence for past or present active aeolian processes. Therefore, wind streaks are thought to represent integrative climate processes. As opposed to the comprehensive and global studies of wind streaks on Mars and Venus, wind streaks on Earth are understudied and poorly investigated, both geomorphologically and by remote sensing. The aim of this study is, thus, to fill the knowledge gap about the wind streaks on Earth by: generating a global map of Earth wind streaks from modern high-resolution remotely sensed imagery; incorporating the streaks in a geographic information system (GIS); and overlaying the GIS layers with boundary layer wind data from general circulation models (GCMs) and data from the ECMWF Reanalysis Interim project. The study defines wind streaks (and thereby distinguishes them from other aeolian features) based not only on their appearance in imagery but more importantly on their surface appearance. This effort is complemented by a focused field investigation to study wind streaks on the ground and from a variety of remotely sensed images (both optical and radar). In this way, we provide a better definition of the physical and geomorphic characteristics of wind streaks and acquire a deeper knowledge of terrestrial wind streaks as a means to better understand global and planetary climate and climate change. In a preliminary study, we detected and mapped over 2,900 wind streaks in the desert regions of Earth distributed in

  17. Mars Eolian Geology at Airphoto Scales: The Large Wind Streaks of Western Arabia Terra

    Science.gov (United States)

    Edgett, Kenneth S.

    2001-01-01

    More than 27,000 pictures at aerial photograph scales (1.5-12 m/pixel) have been acquired by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) since September 1997. The pictures are valuable for testing hypotheses about geologic history and processes of Mars. Of particular interest are eolian features connected to surface albedo patterns. This work is focused on low-albedo wind streaks, some over 100 km long, in western Arabia Terra. Each streak is widest where it originates at an impact crater (typically 25-150 km diameter). The streaks taper downwind. Within the associated craters there is a lower-albedo surface that, in nearly all observed cases, includes barchan dunes indicative of transport in the same direction as the wind streaks. Upwind of the dunes there is usually an outcrop of layered material that might have served as a source for dune sand. MOC images show that the west Arabia streaks consist of a smooth-surfaced, multiple-meters-thick, mantle (smooth at 1.5 m/pixel) that appears to be superposed on local surfaces. No dunes are present, indicating that down-streak transport of sediment via saltation and traction have not occurred. Two models might explain the observed properties: (1) the streaks consist of dark silt- and clay-sized grains deflated from the adjacent crater interiors and deposited from suspension or (2) they are remnants (protected in the lee of impact crater rims) of a formerly much larger, regional covering of low albedo, smooth-surfaced mantle. The latter hypothesis is based on observation of low albedo mantled surfaces occurring south of west Arabia in Terra Meridiani. For reasons yet unknown, a large fraction of the martian equatorial regions are covered by low albedo, mesa-forming material that lies unconformably atop eroded layered and cratered terrain. Both hypotheses are being explored via continued selective targeting of new MOC images as well as analyses of the new data.

  18. Two-color spatial and temporal temperature measurements using a streaked soft x-ray imager.

    Science.gov (United States)

    Moore, A S; Benstead, J; Ahmed, M F; Morton, J; Guymer, T M; Soufli, R; Pardini, T; Hibbard, R L; Bailey, C G; Bell, P M; Hau-Riege, S; Bedzyk, M; Shoup, M J; Regan, S P; Agliata, T; Jungquist, R; Schmidt, D W; Kot, L B; Garbett, W J; Rubery, M S; Skidmore, J W; Gullikson, E; Salmassi, F

    2016-11-01

    A dual-channel streaked soft x-ray imager has been designed and used on high energy-density physics experiments at the National Ignition Facility. This streaked imager creates two images of the same x-ray source using two slit apertures and a single shallow angle reflection from a nickel mirror. Thin filters are used to create narrow band pass images at 510 eV and 360 eV. When measuring a Planckian spectrum, the brightness ratio of the two images can be translated into a color-temperature, provided that the spectral sensitivity of the two images is well known. To reduce uncertainty and remove spectral features in the streak camera photocathode from this photon energy range, a thin 100 nm CsI on 50 nm Al streak camera photocathode was implemented. Provided that the spectral shape is well-known, then uncertainties on the spectral sensitivity limits the accuracy of the temperature measurement to approximately 4.5% at 100 eV.

  19. Two-color spatial and temporal temperature measurements using a streaked soft x-ray imager

    Energy Technology Data Exchange (ETDEWEB)

    Moore, A. S., E-mail: alastair.moore@physics.org; Ahmed, M. F.; Soufli, R.; Pardini, T.; Hibbard, R. L.; Bailey, C. G.; Bell, P. M.; Hau-Riege, S. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); Benstead, J.; Morton, J.; Guymer, T. M.; Garbett, W. J.; Rubery, M. S.; Skidmore, J. W. [Directorate Science and Technology, AWE Aldermaston, Reading RG7 4PR (United Kingdom); Bedzyk, M.; Shoup, M. J.; Regan, S. P.; Agliata, T.; Jungquist, R. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Schmidt, D. W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); and others

    2016-11-15

    A dual-channel streaked soft x-ray imager has been designed and used on high energy-density physics experiments at the National Ignition Facility. This streaked imager creates two images of the same x-ray source using two slit apertures and a single shallow angle reflection from a nickel mirror. Thin filters are used to create narrow band pass images at 510 eV and 360 eV. When measuring a Planckian spectrum, the brightness ratio of the two images can be translated into a color-temperature, provided that the spectral sensitivity of the two images is well known. To reduce uncertainty and remove spectral features in the streak camera photocathode from this photon energy range, a thin 100 nm CsI on 50 nm Al streak camera photocathode was implemented. Provided that the spectral shape is well-known, then uncertainties on the spectral sensitivity limits the accuracy of the temperature measurement to approximately 4.5% at 100 eV.

  20. Characterization of the Series 1000 Camera System

    Energy Technology Data Exchange (ETDEWEB)

    Kimbrough, J; Moody, J; Bell, P; Landen, O

    2004-04-07

    The National Ignition Facility requires a compact network addressable scientific grade CCD camera for use in diagnostics ranging from streak cameras to gated x-ray imaging cameras. Due to the limited space inside the diagnostic, an analog and digital input/output option in the camera controller permits control of both the camera and the diagnostic by a single Ethernet link. The system consists of a Spectral Instruments Series 1000 camera, a PC104+ controller, and power supply. The 4k by 4k CCD camera has a dynamic range of 70 dB with less than 14 electron read noise at a 1MHz readout rate. The PC104+ controller includes 16 analog inputs, 4 analog outputs and 16 digital input/output lines for interfacing to diagnostic instrumentation. A description of the system and performance characterization is reported.

  1. Secondary threshold amplitudes for sinuous streak breakdown

    OpenAIRE

    Cossu, Carlo; Brandt, Luca; Bagheri, Shervin; Henningson, Dan S.

    2011-01-01

    The nonlinear stability of laminar sinuously bent streaks is studied for the plane Couette flow at Re=500 in a nearly minimal box and for the Blasius boundary layer at Re_d*= 700. The initial perturbations are nonlinearly saturated streamwise streaks of amplitude AU perturbed with sinuous perturbations of amplitude AW. The local boundary of the basin of attraction of the linearly stable laminar flow is computed by bisection and projected in the AU – AW plane providing a well defined critical ...

  2. Atomic and molecular phases through attosecond streaking

    DEFF Research Database (Denmark)

    Baggesen, Jan Conrad; Madsen, Lars Bojer

    2011-01-01

    phase of the atomic or molecular ionization matrix elements from the two states through the interference from the two channels. The interference may change the phase of the photoelectron streaking signal within the envelope of the infrared field, an effect to be accounted for when reconstructing short...

  3. Initial Demonstration of 9-MHz Framing Camera Rates on the FAST UV Drive Laser Pulse Trains

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H. [Fermilab; Edstrom Jr., D. [Fermilab; Ruan, J. [Fermilab

    2016-10-09

    We report the configuration of a Hamamatsu C5680 streak camera as a framing camera to record transverse spatial information of green-component laser micropulses at 3- and 9-MHz rates for the first time. The latter is near the time scale of the ~7.5-MHz revolution frequency of the Integrable Optics Test Accelerator (IOTA) ring and its expected synchroton radiation source temporal structure. The 2-D images are recorded with a Gig-E readout CCD camera. We also report a first proof of principle with an OTR source using the linac streak camera in a semi-framing mode.

  4. Suppression of wake's instabilities by optimal streaks

    Science.gov (United States)

    Del Guercio, Gerardo; Cossu, Carlo; Pujals, Gregory

    2014-11-01

    Wakes can sustain large transient energy growth. Optimal perturbations are computed for the cases of parallel, weakly non-parallel and the circular cylinder wakes. Streaks are found to be the optimal amplified structures produced by the non normal energy amplification. The level of energy increases with the spanwise wavelength of the perturbations except in the circular cylinder wake where the optimal is reached for λz ~ 6 D . In parallel wakes these streaks are shown to suppress the absolute instability. Furthermore the global instability of the weakly non-parallel and the circular cylinder wakes can be completely annihilate with moderate streaks amplitudes. The comparison of these spanwise periodic (3D) optimal perturbations with the spanwise uniform (2D) control showed that the energy required to stabilize the wake is always smaller for the 3D control. Moreover the sensitivity of the global mode growth rate is discovered to be quadratic for 3D perturbations while being linear for 2D ones meaning that usual first order sensitivity analysis is unable to predict their larger efficiency.

  5. Understanding baseball team standings and streaks

    Science.gov (United States)

    Sire, C.; Redner, S.

    2009-02-01

    Can one understand the statistics of wins and losses of baseball teams? Are their consecutive-game winning and losing streaks self-reinforcing or can they be described statistically? We apply the Bradley-Terry model, which incorporates the heterogeneity of team strengths in a minimalist way, to answer these questions. Excellent agreement is found between the predictions of the Bradley-Terry model and the rank dependence of the average number team wins and losses in major-league baseball over the past century when the distribution of team strengths is taken to be uniformly distributed over a finite range. Using this uniform strength distribution, we also find very good agreement between model predictions and the observed distribution of consecutive-game team winning and losing streaks over the last half-century; however, the agreement is less good for the previous half-century. The behavior of the last half-century supports the hypothesis that long streaks are primarily statistical in origin with little self-reinforcing component. The data further show that the past half-century of baseball has been more competitive than the preceding half-century.

  6. A new streaked soft x-ray imager for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Benstead, J., E-mail: james.benstead@awe.co.uk; Morton, J.; Guymer, T. M.; Garbett, W. J.; Rubery, M. S.; Skidmore, J. W. [AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Moore, A. S.; Ahmed, M. F.; Soufli, R.; Pardini, T.; Hibbard, R. L.; Bailey, C. G.; Bell, P. M.; Hau-Riege, S. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Bedzyk, M.; Shoup, M. J.; Reagan, S.; Agliata, T.; Jungquist, R. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Schmidt, D. W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); and others

    2016-05-15

    A new streaked soft x-ray imager has been designed for use on high energy-density (HED) physics experiments at the National Ignition Facility based at the Lawrence Livermore National Laboratory. This streaked imager uses a slit aperture, single shallow angle reflection from a nickel mirror, and soft x-ray filtering to, when coupled to one of the NIF’s x-ray streak cameras, record a 4× magnification, one-dimensional image of an x-ray source with a spatial resolution of less than 90 μm. The energy band pass produced depends upon the filter material used; for the first qualification shots, vanadium and silver-on-titanium filters were used to gate on photon energy ranges of approximately 300–510 eV and 200–400 eV, respectively. A two-channel version of the snout is available for x-ray sources up to 1 mm and a single-channel is available for larger sources up to 3 mm. Both the one and two-channel variants have been qualified on quartz wire and HED physics target shots.

  7. Avoiding acidic region streaking in two-dimensional gel ...

    Indian Academy of Sciences (India)

    2014-07-21

    Jul 21, 2014 ... Acidic region streaking (ARS) is one of the lacunae in two-dimensional gel electrophoresis (2DE) of bacterial proteome. This streaking is primarily caused by nucleic acid (NuA) contamination and poses major problem in the downstream processes like image analysis and protein identification. Although ...

  8. Automatic streak endpoint localization from the cornerness metric

    Science.gov (United States)

    Sease, Brad; Flewelling, Brien; Black, Jonathan

    2017-05-01

    Streaked point sources are a common occurrence when imaging unresolved space objects from both ground- and space-based platforms. Effective localization of streak endpoints is a key component of traditional techniques in space situational awareness related to orbit estimation and attitude determination. To further that goal, this paper derives a general detection and localization method for streak endpoints based on the cornerness metric. Corners detection involves searching an image for strong bi-directional gradients. These locations typically correspond to robust structural features in an image. In the case of unresolved imagery, regions with a high cornerness score correspond directly to the endpoints of streaks. This paper explores three approaches for global extraction of streak endpoints and applies them to an attitude and rate estimation routine.

  9. Statistical characteristics of streak artifacts on CT images: Relationship between streak artifacts and mA s values

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Kuniahru; Ikeda, Mitsuru; Enchi, Yukihiro; Niimi, Takanaga [Department of Radiological Technology, Nagoya University School of Health Sciences, 1-20 Daikominami 1-chome, Higashi-ku, Nagoya, 461-8673 (Japan); Department of Radiology, Osaka University Hospital, 2-15 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Department of Radiological Technology, Nagoya University School of Health Sciences, 1-20 Daikominami 1-chome, Higashi-ku, Nagoya 461-8673 (Japan)

    2009-02-15

    The purpose of this study is to investigate how streak artifacts on computed tomography (CT) images vary with reduction in radiation doses by assessing the quantitative relationship between the streak artifacts and milliampere-time product (mA s) values. A commercially available chest phantom was used to measure the streak artifacts on the CT images obtained using a 4- and 16-multidetector-row helical CT scanners with various mA s values at a constant tube voltage of 120 kVp. The cardiac slice image was employed as a target image for evaluating the streak artifacts on the CT image. Eighty parallel line segments with a length of 20 pixels were placed perpendicular to numerous streak artifacts on the cardiac slice image, and the largest difference between adjacent CT values in each of the 80 CT-value profiles of these line segments was employed as a feature variable of streak artifacts; these feature variables have been analyzed by the extreme value theory. The largest difference between adjacent CT values in each CT-value profile can be statistically modeled by a Gumbel distribution. Further, the maximum level of streak artifacts on CT images that will be tolerated for clinical use and low-dose CT screening examination was expected to be estimated using the location parameter in the Gumbel distribution.

  10. Infrared Camera

    Science.gov (United States)

    1997-01-01

    A sensitive infrared camera that observes the blazing plumes from the Space Shuttle or expendable rocket lift-offs is capable of scanning for fires, monitoring the environment and providing medical imaging. The hand-held camera uses highly sensitive arrays in infrared photodetectors known as quantum well infrared photo detectors (QWIPS). QWIPS were developed by the Jet Propulsion Laboratory's Center for Space Microelectronics Technology in partnership with Amber, a Raytheon company. In October 1996, QWIP detectors pointed out hot spots of the destructive fires speeding through Malibu, California. Night vision, early warning systems, navigation, flight control systems, weather monitoring, security and surveillance are among the duties for which the camera is suited. Medical applications are also expected.

  11. An Optical Streak Diagnostic for Observing Anode-Cathode Plasmas for Radiographic Source Development

    Energy Technology Data Exchange (ETDEWEB)

    Droemer, Darryl W. [National Security Technologies, LLC; Crain, Marlon D.; Lare, Gregory A. [National Security Technologies, LLC; Bennett, Nichelle L. [National Security Technologies, LLC; Johnston, Mark D. [Sandia National Laboratories

    2013-06-13

    National Security Technologies, LLC, and Sandia National Laboratories are collaborating in the development of pulsed power–driven flash x-ray radiographic sources that utilize high-intensity electron beam diodes. The RITS 6 (Radiographic Integrated Test Stand) accelerator at Sandia is used to drive a self magnetic pinch diode to produce a Bremsstrahlung x-ray source. The high electric fields and current densities associated with these short A-K gap pinch beam diodes present many challenges in diode development. Plasmas generated at both the anode and cathode affect the diode performance, which is manifested in varying spot (source) sizes, total dose output, and impedance profiles. Understanding the nature of these plasmas including closure rates and densities is important in modeling their behavior and providing insight into their mitigation. In this paper we describe a streak camera–based optical diagnostic that is capable of observing and measuring plasma evolution within the A-K gap. By imaging a region of interest onto the input slit of a streak camera, we are able to produce a time-resolved one-dimensional image of the evolving plasma. Typical data are presented.

  12. Streak detection and analysis pipeline for optical images

    Science.gov (United States)

    Virtanen, J.; Granvik, M.; Torppa, J.; Muinonen, K.; Poikonen, J.; Lehti, J.; Säntti, T.; Komulainen, T.; Flohrer, T.

    2014-07-01

    We describe a novel data processing and analysis pipeline for optical observations of moving objects, either of natural (asteroids, meteors) or artificial origin (satellites, space debris). The monitoring of the space object populations requires reliable acquisition of observational data to support the development and validation of population models, and to build and maintain catalogues of orbital elements. The orbital catalogues are, in turn, needed for the assessment of close approaches (for asteroids, with the Earth; for satellites, with each other) and for the support of contingency situations or launches. For both types of populations, there is also increasing interest to detect fainter objects corresponding to the small end of the size distribution. We focus on the low signal-to-noise (SNR) detection of objects with high angular velocities, resulting in long and faint object trails, or streaks, in the optical images. The currently available, mature image processing algorithms for detection and astrometric reduction of optical data cover objects that cross the sensor field-of-view comparably slowly, and, particularly for satellites, within a rather narrow, predefined range of angular velocities. By applying specific tracking techniques, the objects appear point-like or as short trails in the exposures. However, the general survey scenario is always a 'track-before-detect' problem, resulting in streaks of arbitrary lengths. Although some considerations for low-SNR processing of streak-like features are available in the current image processing and computer vision literature, algorithms are not readily available yet. In the ESA-funded StreakDet (Streak detection and astrometric reduction) project, we develop and evaluate an automated processing pipeline applicable to single images (as compared to consecutive frames of the same field) obtained with any observing scenario, including space-based surveys and both low- and high-altitude populations. The algorithmic

  13. CCD Camera

    Science.gov (United States)

    Roth, Roger R.

    1983-01-01

    A CCD camera capable of observing a moving object which has varying intensities of radiation eminating therefrom and which may move at varying speeds is shown wherein there is substantially no overlapping of successive images and wherein the exposure times and scan times may be varied independently of each other.

  14. Angioid streaks, clinical course, complications, and current therapeutic management

    Directory of Open Access Journals (Sweden)

    Ilias Georgalas

    2008-12-01

    Full Text Available Ilias Georgalas1, Dimitris Papaconstantinou2, Chrysanthi Koutsandrea2, George Kalantzis2, Dimitris Karagiannis2, Gerasimos Georgopoulos2, Ioannis Ladas21Department of Ophthalmology, “G. Gennimatas” Hospital of Athens, NHS, Athens, Greece; 2Department of Ophthalmology, “G. Gennimatas” Hospital of Athens, University of Athens, Athens, GreeceAbstract: Angioid streaks are visible irregular crack-like dehiscences in Bruch’s membrane that are associated with atrophic degeneration of the overlying retinal pigmented epithelium. Angioid streaks may be associated with pseudoxanthoma elasticum, Paget’s disease, sickle-cell anemia, acromegaly, Ehlers–Danlos syndrome, and diabetes mellitus, but also appear in patients without any systemic disease. Patients with angioid streaks are generally asymptomatic, unless the lesions extend towards the foveola or develop complications such as traumatic Bruch’s membrane rupture or macular choroidal neovascularization (CNV. The visual prognosis in patients with CNV secondary to angioid streaks if untreated, is poor and most treatment modalities, until recently, have failed to limit the devastating impact of CNV in central vision. However, it is likely that treatment with antivascular endothelial growth factor, especially in treatment-naive eyes to yield favorable results in the future and this has to be investigated in future studies.Keywords: angioid streaks, pseudoxanthoma elasticum, choroidal neovascularization

  15. Time delays for attosecond streaking in photoionization of neon

    CERN Document Server

    Feist, Johannes; Nagele, Stefan; Pazourek, Renate; Burgdörfer, Joachim; Guan, Xiaoxu; Bartschat, Klaus; Schneider, Barry I

    2014-01-01

    We revisit the time-resolved photoemission in neon atoms as probed by attosecond streaking. We calculate streaking time shifts for the emission of 2p and 2s electrons and compare the relative delay as measured in a recent experiment by Schultze et al. [Science 328, 1658 (2010)]. The B-spline R-matrix method is employed to calculate accurate Eisenbud-Wigner-Smith time delays from multi- electron dipole transition matrix elements for photoionization. The additional laser field-induced time shifts in the exit channel are obtained from separate, time-dependent simulations of a full streaking process by solving the time-dependent Schr\\"odinger equation on the single-active-electron level. The resulting accurate total relative streaking time shifts between 2s and 2p emission lie well below the experimental data. We identify the presence of unresolved shake-up satellites in the experiment as a potential source of error in the determination of streaking time shifts.

  16. Small-size streak tube for imaging lidar

    Science.gov (United States)

    Tian, Jinshou; Hui, Dandan; Luo, Duan; Wang, Tao; Zhang, Jun; Chen, Shaorong; Jia, Hui

    2017-02-01

    Streak tube imaging lidar, as a novel flash lidar, due to its advantages of higher resolution for low contrast conditions, compact and rugged physical configurations, small image distortions owing to its scannerless design, and higher image update rates, has immense potential to provide 3D single-laser-pulse scannerless imaging, 3D multispectral imaging, 3D multispectral fluorescence imaging, and 3D polarimetry. In order to further reduce the size and enlarge the field of view (FOV) of the lidar system, we designed a super small-size, large photocathode area and meshless streak tube with spherical cathode and screen. With the aid of Computer Simulation Technology Software package (CST), a model of the streak tube was built, and its predominant performances were illustrated via tracking electron trajectories. Spatial resolution of the streak tube reaches 20lp/mm over the entire ∅28mm photocathode working area, and its temporal resolution is better than 30ps. Most importantly, the external dimensions of the streak tube are only ∅50mmx100mm. And several prototypes are already manufactured on the basis of the computer design.

  17. Optimum Dietary Protein Level for Blue Streak Hap, Labidochromis caeruleus

    OpenAIRE

    Ergün, Sebahattin; Güroy, Derya; Tekeşoğlu, Haluk; Güroy, Betül; Çelik, İhsan; Tekinay, A. Adem; Bulut, Musa

    2010-01-01

    An experiment was designed to determine the optimum dietary protein level of a freshwater ornamental fish, Blue streak hap (Labidochromis caeruleus). Four isocaloric fish meal based diets ranging from 30% to 45% in protein were fed to triplicate groups of Blue streak hap for 8 weeks. Fish (initial weight, 0.85 g) were reared in twelve 50 L aquarium with biological filter and controlled temperature (27.5°C), in stocking density of ten fish/aquarium. Results showed that dietary protein level si...

  18. Using an ultra-high speed camera to capture a tube expansion test

    CSIR Research Space (South Africa)

    Snyman, Izak M

    2016-09-01

    Full Text Available of such parameters is for the JWL equation of state that models the detonation of an explosive. Tube or cylinder expansion tests are a standard way to determine the JWL parameters of such an explosive. A streak camera normally captures the copper tube expansion...

  19. Detection of banana streak virus (BSV) Tamil Nadu isolate (India ...

    African Journals Online (AJOL)

    Yomi

    2012-10-09

    Oct 9, 2012 ... 2Department of Fruit Crops, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu, India. Accepted 5 September, 2012. Banana streak virus (BSV) is of quarantine significance since Musa is a vegetatively propagated crop. Diagnosis by symptomatology is unreliable because the symptoms ...

  20. Cassava brown streak disease effects on leaf metabolites and ...

    African Journals Online (AJOL)

    Cassava Brown Streak Disease (CBSD) is a threat to productivity and product quality in East Africa. The objective of this study was to understand the effect of CBSD on the primary photosynthetic apparatus of cassava (Manihot esculenta Crantz). Three cassava varieties with varying levels of reaction to infection by CBSD ...

  1. Hitting is contagious in baseball: evidence from long hitting streaks.

    Directory of Open Access Journals (Sweden)

    Joel R Bock

    Full Text Available Data analysis is used to test the hypothesis that "hitting is contagious". A statistical model is described to study the effect of a hot hitter upon his teammates' batting during a consecutive game hitting streak. Box score data for entire seasons comprising [Formula: see text] streaks of length [Formula: see text] games, including a total [Formula: see text] observations were compiled. Treatment and control sample groups ([Formula: see text] were constructed from core lineups of players on the streaking batter's team. The percentile method bootstrap was used to calculate [Formula: see text] confidence intervals for statistics representing differences in the mean distributions of two batting statistics between groups. Batters in the treatment group (hot streak active showed statistically significant improvements in hitting performance, as compared against the control. Mean [Formula: see text] for the treatment group was found to be [Formula: see text] to [Formula: see text] percentage points higher during hot streaks (mean difference increased [Formula: see text] points, while the batting heat index [Formula: see text] introduced here was observed to increase by [Formula: see text] points. For each performance statistic, the null hypothesis was rejected at the [Formula: see text] significance level. We conclude that the evidence suggests the potential existence of a "statistical contagion effect". Psychological mechanisms essential to the empirical results are suggested, as several studies from the scientific literature lend credence to contagious phenomena in sports. Causal inference from these results is difficult, but we suggest and discuss several latent variables that may contribute to the observed results, and offer possible directions for future research.

  2. Intelligent detection and removing of straight periodic streaks on digital images

    Science.gov (United States)

    Zhao, Zehao; Sheng, Hui; Xu, Xianfeng

    2017-08-01

    Straight periodic steaks are common negative errors on images, an intelligent method is proposed to test and remove the periodic streaks on digital images. Because of many artificial errors or negative experiment factors, digital images are always contaminated by straight periodic streaks, which will correspondently incur error information on them. By Fast Two Dimensional Fourier Transform, the space spectra from these periodic streaks are discrete and can be test intelligently. After eliminate these frequency ingredient, the periodic streaks disappear after inverse Fourier Transform. The numerical simulation experiment shows that this method is robust in detesting and removing the periodic streaks on digital figures.

  3. Analysis of Dark Slope Streaks on Mars based on Multitemporal Imagery and Digital Elevation Model derived from HRSC Data

    Science.gov (United States)

    Schreiner, Bjoern Peter; Walter, Sebastian; Muller, Jan-Peter; Sidiropoulos, Panagiotis

    2016-10-01

    Recurring slope lineae (RSL) on Mars are dark and narrow downhill oriented surface features found in equatorial regions (1) associated with water or hydrated salt flows (2). On the other hand there are Dark Slope Streaks which seem to be dry avalanches on dust covered slopes (3). The origin of both ist still under discussion. We found linear features in eastern Noctis Labyrinthus region (6°S, 265°E) with lengths of up to several kilometres and lateral extensions of 20-30 metres. RSL fade andrecur in the same location over multiple Mars years (4). Similarily, Dark Slope Streaks form on at least annual to decade-long timescales (5). During 10 years of HRSC observation time (2005-2015) several linear features in Noctis Labyrinthus changed in visibility. Slopeparameters and seasonal illumination conditions are investigated based ona DTM derived from HRSC data. Also particle flow along streaks has been modelled. Feature and change identification is presented involving spatial filtering and DTM analysis.The research leading to these results has received funding from theEuropean Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement n° 607379.(1) McEwen, A.S., et al. (2014): Recurring slope lineae in equatorialregions of Mars. Nat. Geosci 7: 53-58.(2) Ojha, L. et al. (2015): Spectral evidence for hydrated salts inrecurring slope linear on Mars. Nat. Geosci, DOI:10.1038/NGEO2 546.(3) Sullivan, R. et al. (2001). Mass Movement Slope Streaks Imaged by theMars Orbiter Camera. J. Geophys. Res., 106(E10), 23,607-23,633.(4) McEwen, A.S., et al. (2011): Seasonal Flows on Warm Martian Slopes.Science, Vol. 333, Issue 6043, pp. 740-743.(5) Malin, M.C.; Edgett, K.S. (2001). Mars Global Surveyor Mars OrbiterCamera: Interplanetary cruise through primary mission. J. Geophys. Res., 106(E10), 23,429-23,570.

  4. A multi-wavelength streak-optical-pyrometer for warm-dense matter experiments at NDCX-I and NDCX-II

    Energy Technology Data Exchange (ETDEWEB)

    Ni, P.A., E-mail: pani@lbl.gov; Bieniosek, F.M.; Henestroza, E.; Lidia, S.M.

    2014-01-01

    We report on a multi-wavelength streak-optical-pyrometer (SOP) developed the for warm-dense-matter (WDM) experiments at the existing NDCX-I facility and the NDCX-II facility currently being commissioned at LBNL. The SOP served as the primary temperature diagnostic in the recent NDCX-I experiments, in which an intense K{sup +} beam was used to heat different metal samples into WDM states. The SOP consists of a spectral grating (visible and near-infrared spectral range) and a fast, high-dynamic-range optical streak camera. The instrument is calibrated absolutely with a NIST-traceable tungsten ribbon lamp and can itself be considered as an absolutely calibrated, time-resolving spectrometer. The sample temperature is determined from fitting the recorded thermal spectrum into the Planck formula multiplied by a model of emissivity.

  5. Overview of the ARGOS X-ray framing camera for Laser MegaJoule

    Energy Technology Data Exchange (ETDEWEB)

    Trosseille, C., E-mail: clement.trosseille@cea.fr; Aubert, D.; Auger, L.; Bazzoli, S.; Brunel, P.; Burillo, M.; Chollet, C.; Jasmin, S.; Maruenda, P.; Moreau, I.; Oudot, G.; Raimbourg, J.; Soullié, G.; Stemmler, P.; Zuber, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Beck, T. [CEA, DEN, CADARACHE, F-13108 St Paul lez Durance (France); Gazave, J. [CEA, DAM, CESTA, F-33116 Le Barp (France)

    2014-11-15

    Commissariat à l’Énergie Atomique et aux Énergies Alternatives has developed the ARGOS X-ray framing camera to perform two-dimensional, high-timing resolution imaging of an imploding target on the French high-power laser facility Laser MegaJoule. The main features of this camera are: a microchannel plate gated X-ray detector, a spring-loaded CCD camera that maintains proximity focus in any orientation, and electronics packages that provide remotely-selectable high-voltages to modify the exposure-time of the camera. These components are integrated into an “air-box” that protects them from the harsh environmental conditions. A miniaturized X-ray generator is also part of the device for in situ self-testing purposes.

  6. Observation of molecular dipole excitations by attosecond self-streaking

    CERN Document Server

    Wachter, Georg; Sato, Shunsuke A; Pazourek, Renate; Wais, Michael; Lemell, Christoph; Tong, Xiao-Min; Yabana, Kazuhiro; Burgdörfer, Joachim

    2015-01-01

    We propose a protocol to probe the ultrafast evolution and dephasing of coherent electronic excitation in molecules in the time domain by the intrinsic streaking field generated by the molecule itself. Coherent electronic motion in the endohedral fullerene \\Necsixty~is initiated by a moderately intense femtosecond UV-VIS pulse leading to coherent oscillations of the molecular dipole moment that persist after the end of the laser pulse. The resulting time-dependent molecular near-field is probed through the momentum modulation of photoemission from the central neon atom by a time-delayed attosecond XUV pulse. Our ab-initio time-dependent density functional theory and classical trajectory simulations predict that this self-streaking signal accurately traces the molecular dipole oscillations in real time. We discuss the underlying processes and give an analytical model that captures the essence of our ab-initio simulations.

  7. Small-size meshless 50 ps streak tube

    Science.gov (United States)

    Ageeva, N. V.; Andreev, S. V.; Belolipetski, V. S.; Bryukhnevich, G. I.; Greenfield, D. E.; Ivanova, S. R.; Kaverin, A. M.; Khohlova, A. N.; Kuz'menko, E. A.; Levina, G. P.; Makushina, V. A.; Monastyrskiy, M. A.; Schelev, M. Ya.; Semichastnova, Z. M.; Serdyuchenko, Yu. N.; Skaballanovich, T. A.; Sokolov, V. E.

    2008-11-01

    In contrast to the conventional image intensifier with large work area, a streak image tube should possess additional important feature - the comparatively small temporal distortion at the entire work area of the photocathode. With this additional engineering restriction taken into account, a novel small-size meshless streak image tube has been developed by means of numerical optimization. The tube with 25-mm wide work area contains a pair of deflection plates to sweep the electron image along the 25 mm output phosphor screen that is separated by 100 mm from the photocathode. The electron image can be shuttered with a 300 V blanking electric pulse. Electron-optical magnification of the tube is unit; spatial resolution reaches 30 lp/mm over the entire photocathode work area; temporal resolution lies in the 20 - 50 ps range, depending on the accelerating voltage (6 - 15 kV).

  8. Silent polypoidal choroidal vasculopathy in a patient with angioid streaks

    Directory of Open Access Journals (Sweden)

    Zafer Cebeci

    2016-06-01

    Full Text Available ABSTRACT We present a case of silent polypoidal choroidal vasculopathy (PCV in a patient with angioid streaks. PCV was detected during a routine ophthalmic examination and confirmed by fluorescein angiography, indocyanine green angiography, and optical coherence tomography. After 2 years of follow-up, the PCV remained silent without any complications. We report this rare coexistence and review literature on this topic.

  9. Maize streak virus: an old and complex 'emerging' pathogen.

    Science.gov (United States)

    Shepherd, Dionne N; Martin, Darren P; Van Der Walt, Eric; Dent, Kyle; Varsani, Arvind; Rybicki, Edward P

    2010-01-01

    Maize streak virus (MSV; Genus Mastrevirus, Family Geminiviridae) occurs throughout Africa, where it causes what is probably the most serious viral crop disease on the continent. It is obligately transmitted by as many as six leafhopper species in the Genus Cicadulina, but mainly by C. mbila Naudé and C. storeyi. In addition to maize, it can infect over 80 other species in the Family Poaceae. Whereas 11 strains of MSV are currently known, only the MSV-A strain is known to cause economically significant streak disease in maize. Severe maize streak disease (MSD) manifests as pronounced, continuous parallel chlorotic streaks on leaves, with severe stunting of the affected plant and, usuallly, a failure to produce complete cobs or seed. Natural resistance to MSV in maize, and/or maize infections caused by non-maize-adapted MSV strains, can result in narrow, interrupted streaks and no obvious yield losses. MSV epidemiology is primarily governed by environmental influences on its vector species, resulting in erratic epidemics every 3-10 years. Even in epidemic years, disease incidences can vary from a few infected plants per field, with little associated yield loss, to 100% infection rates and complete yield loss. The only virus species known to cause MSD is MSV, the type member of the Genus Mastrevirus in the Family Geminiviridae. In addition to the MSV-A strain, which causes the most severe form of streak disease in maize, 10 other MSV strains (MSV-B to MSV-K) are known to infect barley, wheat, oats, rye, sugarcane, millet and many wild, mostly annual, grass species. Seven other mastrevirus species, many with host and geographical ranges partially overlapping those of MSV, appear to infect primarily perennial grasses. MSV and all related grass mastreviruses have single-component, circular, single-stranded DNA genomes of approximately 2700 bases, encapsidated in 22 x 38-nm geminate particles comprising two incomplete T = 1 icosahedra, with 22 pentameric capsomers

  10. Optical gating and streaking of free electrons with sub-optical cycle precision

    Science.gov (United States)

    Kozák, M.; McNeur, J.; Leedle, K. J.; Deng, H.; Schönenberger, N.; Ruehl, A.; Hartl, I.; Harris, J. S.; Byer, R. L.; Hommelhoff, P.

    2017-01-01

    The temporal resolution of ultrafast electron diffraction and microscopy experiments is currently limited by the available experimental techniques for the generation and characterization of electron bunches with single femtosecond or attosecond durations. Here, we present proof of principle experiments of an optical gating concept for free electrons via direct time-domain visualization of the sub-optical cycle energy and transverse momentum structure imprinted on the electron beam. We demonstrate a temporal resolution of 1.2±0.3 fs. The scheme is based on the synchronous interaction between electrons and the near-field mode of a dielectric nano-grating excited by a femtosecond laser pulse with an optical period duration of 6.5 fs. The sub-optical cycle resolution demonstrated here is promising for use in laser-driven streak cameras for attosecond temporal characterization of bunched particle beams as well as time-resolved experiments with free-electron beams. PMID:28120930

  11. Interactions between performance pressure, performance streaks, and attentional focus.

    Science.gov (United States)

    Gray, Rob; Allsop, Jonathan

    2013-08-01

    How is performance under pressure influenced by the history of events that precede it, and how does the pressure outcome influence the series of events that follow? A baseball batting simulation was used with college players to investigate these questions. In Experiment 1, the difficulty of the simulation was first adaptively adjusted to equate performance level. Batters next completed 20 at-bats used to classify them into one of three performance groups (normal, cold streak, or hot streak) followed by a one at-bat pressure condition. Finally, performance was evaluated over a period of 20 postpressure at-bats. In Experiment 2, a series of secondary tasks were added to assess attentional focus. In both experiments, whether batters succeeded or failed under pressure was significantly related to their performance history immediately before the pressure event, with the normal group having the poorest pressure performance. Performance postpressure was significantly related to both the pressure outcome and prepressure performance. These performance effects were related to changes in the batter's attentional focus as shown by changes in secondary task accuracy.

  12. Making Ceramic Cameras

    Science.gov (United States)

    Squibb, Matt

    2009-01-01

    This article describes how to make a clay camera. This idea of creating functional cameras from clay allows students to experience ceramics, photography, and painting all in one unit. (Contains 1 resource and 3 online resources.)

  13. Quantitative trait loci for resistance to maize streak virus disease in ...

    African Journals Online (AJOL)

    Maize streak virus disease is an important disease of maize in Kenya. In this study, we mapped and characterized quantitative trait loci affecting resistance to maize streak virus in maize populations of S4 families from the cross of one resistant MAL13 and one susceptible MAL9 recombinant inbred lines. Resistance was ...

  14. Adapting Virtual Camera Behaviour

    DEFF Research Database (Denmark)

    Burelli, Paolo

    2013-01-01

    In a three-dimensional virtual environment aspects such as narrative and interaction completely depend on the camera since the camera defines the player’s point of view. Most research works in automatic camera control aim to take the control of this aspect from the player to automatically gen...

  15. Digital Pinhole Camera

    Science.gov (United States)

    Lancor, Rachael; Lancor, Brian

    2014-01-01

    In this article we describe how the classic pinhole camera demonstration can be adapted for use with digital cameras. Students can easily explore the effects of the size of the pinhole and its distance from the sensor on exposure time, magnification, and image quality. Instructions for constructing a digital pinhole camera and our method for…

  16. On the stability of large-scale streaks in turbulent Couette and Poiseulle flows

    Science.gov (United States)

    Park, Junho; Hwang, Yongyun; Cossu, Carlo

    2011-01-01

    The linear secondary stability of large-scale optimal streaks in turbulent Couette flow at Re=52 and Poiseulle flow at Re=300 is investigated. The streaks are computed by solving the nonlinear two-dimensional Reynolds-averaged Navier-Stokes equations using an eddy-viscosity model. Optimal initial conditions leading the largest linear transient growth are used, and as the amplitude of the initial vortices increases, the amplitude of streaks gradually increases. Instabilities of the streaks appear when their amplitude exceeds approximately 18% of the velocity difference between walls in turbulent Couette flow and 21% of the centerline velocity in turbulent Poiseuille flow. When the amplitude of the streaks is sufficiently large, the instabilities attain significant growth rates in a finite range of streamwise wavenumbers that shows good agreement with the typical streamwise wavenumbers of the large-scale motions in the outer region.

  17. Vascular Streak Dieback: Penyakit Baru Tanaman Kakao di Sumatera Barat

    Directory of Open Access Journals (Sweden)

    Jumsu Trisno

    2016-11-01

    Full Text Available Vascular streak dieback (VSD symptoms was reported recently in several cacao plantations in West Sumatera.  Disease incidence reached 58.82–100% with disease intensity of 24.29–44.71%.  In some cases, dead plant was also found. Fungal isolation was performed to identify the agents associated with VSD.  Plant samples showing VSD symptoms was collected from 3 locations of cacao production center in West Sumatera, i.e. Limapuluh Kota regency, Padang Pariaman regency, and Padang city.  Small pieces of leaf and twig were plated on water agar and potato dextrose agar medium for fungal isolation.  Morphology of hifa, basidiocarp, and basidiospora observed from fungi colonies indicated the presence of Ceratobasidium theobromae on infected plant samples.  This is the first report on the association of C. theobromae on cacao in West Sumatera. 

  18. Traffic camera system development

    Science.gov (United States)

    Hori, Toshi

    1997-04-01

    The intelligent transportation system has generated a strong need for the development of intelligent camera systems to meet the requirements of sophisticated applications, such as electronic toll collection (ETC), traffic violation detection and automatic parking lot control. In order to achieve the highest levels of accuracy in detection, these cameras must have high speed electronic shutters, high resolution, high frame rate, and communication capabilities. A progressive scan interline transfer CCD camera, with its high speed electronic shutter and resolution capabilities, provides the basic functions to meet the requirements of a traffic camera system. Unlike most industrial video imaging applications, traffic cameras must deal with harsh environmental conditions and an extremely wide range of light. Optical character recognition is a critical function of a modern traffic camera system, with detection and accuracy heavily dependent on the camera function. In order to operate under demanding conditions, communication and functional optimization is implemented to control cameras from a roadside computer. The camera operates with a shutter speed faster than 1/2000 sec. to capture highway traffic both day and night. Consequently camera gain, pedestal level, shutter speed and gamma functions are controlled by a look-up table containing various parameters based on environmental conditions, particularly lighting. Lighting conditions are studied carefully, to focus only on the critical license plate surface. A unique light sensor permits accurate reading under a variety of conditions, such as a sunny day, evening, twilight, storms, etc. These camera systems are being deployed successfully in major ETC projects throughout the world.

  19. Blue Nevus with a Dermoscopic Appearance of Peripheral Streaks with Branches

    Directory of Open Access Journals (Sweden)

    Sachiko Sakamoto

    2014-02-01

    Full Text Available Blue nevi are dermal dendritic melanocytic proliferations presenting as papules, nodules or plaques of blue, blue-gray or blue-brown color. Dermoscopic appearance commonly shows global patterns as homogeneous mono/dichromatic pigmentation and multichromatic pigmentation. Here, we report the case of a blue nevus with the dermoscopic feature of peripheral streaks with branches. With histopathologic deep sections, we confirmed that dermal dendritic melanocytes were distributed in the direction of the streaks. We emphasize that streaks are a rare but important sign of blue nevi.

  20. The VISTA infrared camera

    Science.gov (United States)

    Dalton, G. B.; Caldwell, M.; Ward, A. K.; Whalley, M. S.; Woodhouse, G.; Edeson, R. L.; Clark, P.; Beard, S. M.; Gallie, A. M.; Todd, S. P.; Strachan, J. M. D.; Bezawada, N. N.; Sutherland, W. J.; Emerson, J. P.

    2006-06-01

    We describe the integration and test phase of the construction of the VISTA Infrared Camera, a 64 Megapixel, 1.65 degree field of view 0.9-2.4 micron camera which will soon be operating at the cassegrain focus of the 4m VISTA telescope. The camera incorporates sixteen IR detectors and six CCD detectors which are used to provide autoguiding and wavefront sensing information to the VISTA telescope control system.

  1. Solid state video cameras

    CERN Document Server

    Cristol, Y

    2013-01-01

    Solid State Video Cameras reviews the state of the art in the field of solid-state television cameras as compiled from patent literature. Organized into 10 chapters, the book begins with the basic array types of solid-state imagers and appropriate read-out circuits and methods. Documents relating to improvement of picture quality, such as spurious signal suppression, uniformity correction, or resolution enhancement, are also cited. The last part considerssolid-state color cameras.

  2. Airborne Network Camera Standard

    Science.gov (United States)

    2015-06-01

    Optical Systems Group Document 466-15 AIRBORNE NETWORK CAMERA STANDARD DISTRIBUTION A: APPROVED FOR PUBLIC RELEASE...Airborne Network Camera Standard 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER...without the focus of standardization for interoperable command and control, storage, and data streaming has been the airborne network camera systems used

  3. Willapa NWR: Initial Survey Instructions for Streaked Horned Lark Density and Reproductive Success

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The streaked horned lark subspecies represents a small endemic population that breeds and winters in only a few locations in Oregon and Washington. It is perhaps the...

  4. Black leaf streak disease affects starch metabolism in banana fruit.

    Science.gov (United States)

    Saraiva, Lorenzo de Amorim; Castelan, Florence Polegato; Shitakubo, Renata; Hassimotto, Neuza Mariko Aymoto; Purgatto, Eduardo; Chillet, Marc; Cordenunsi, Beatriz Rosana

    2013-06-12

    Black leaf streak disease (BLSD), also known as black sigatoka, represents the main foliar disease in Brazilian banana plantations. In addition to photosynthetic leaf area losses and yield losses, this disease causes an alteration in the pre- and postharvest behavior of the fruit. The aim of this work was to investigate the starch metabolism of fruits during fruit ripening from plants infected with BLSD by evaluating carbohydrate content (i.e., starch, soluble sugars, oligosaccharides, amylose), phenolic compound content, phytohormones, enzymatic activities (i.e., starch phosphorylases, α- and β-amylase), and starch granules. The results indicated that the starch metabolism in banana fruit ripening is affected by BLSD infection. Fruit from infested plots contained unusual amounts of soluble sugars in the green stage and smaller starch granules and showed a different pattern of superficial degradation. Enzymatic activities linked to starch degradation were also altered by the disease. Moreover, the levels of indole-acetic acid and phenolic compounds indicated an advanced fruit physiological age for fruits from infested plots.

  5. Thermal Cameras and Applications

    DEFF Research Database (Denmark)

    Gade, Rikke; Moeslund, Thomas B.

    2014-01-01

    Thermal cameras are passive sensors that capture the infrared radiation emitted by all objects with a temperature above absolute zero. This type of camera was originally developed as a surveillance and night vision tool for the military, but recently the price has dropped, significantly opening up...

  6. Control of Vascular Streak Dieback Disease of Cocoa with Flutriafol Fungicides

    Directory of Open Access Journals (Sweden)

    Febrilia Nur'aini

    2014-12-01

    Full Text Available Vascular streak dieback caused by the fungus Oncobasidium theobromae is one of the important diseases in cocoa crop in Indonesia. One approach to control the disease is by using fungicides. The aim of this research was to determine the effect of class triazole fungicides to the intensity of the vascular streak dieback disease on cocoa seedling phase, immature and mature cocoa. Experiments were conducted in Kotta Blater, PTPN XII and Kaliwining, Indonesian  Coffee and Cocoa Research Institute. Flutriafol 250 g/l with a concentration 0,05%, 0,1% and 0,15% foliar sprayed on cocoa seedlings, immature and mature cocoa. Active compound combination of Azoxystrobin and Difenoconazole with 0,1% concentration used as a comparation fungicides. The result showed that Flutriafol with 0,05%, 0,1% and 0,15% concentration and Azoxystrobin & Difenoconazol with 0,1% concentration could suppress the vascular streak dieback disease on seedlings. On immature plants, the application of Flutriafol was not effectively suppress the vascular streak dieback disease whereas the fungicide comparison could suppress with the efficacy level of 46.22%. On mature plants,both of fungicides could not suppress the vascular streak dieback disease. Key words: Fungicide, cocoa, vascular streak dieback, triazole, flutriafol, azoxystrobin+difenoconazol

  7. Kitt Peak speckle camera.

    Science.gov (United States)

    Breckinridge, J B; McAlister, H A; Robinson, W G

    1979-04-01

    The speckle camera in regular use at Kitt Peak National Observatory since 1974 is described in detail. The design of the atmospheric dispersion compensation prisms, the use of film as a recording medium, the accuracy of double star measurements, and the next generation speckle camera are discussed. Photographs of double star speckle patterns with separations from 1.4 sec of arc to 4.7 sec of arc are shown to illustrate the quality of image formation with this camera, the effects of seeing on the patterns, and to illustrate the isoplanatic patch of the atmosphere.

  8. Mars Observer Camera

    OpenAIRE

    Malin, M. C.; Danielson, G. E.; Ingersoll, A. P.; Masursky, H.; J. Veverka(Massachusetts Institute of Technology, Cambridge, U.S.A.); Ravine, M. A.; Soulanille, T.A.

    1992-01-01

    The Mars Observer camera (MOC) is a three-component system (one narrow-angle and two wide-angle cameras) designed to take high spatial resolution pictures of the surface of Mars and to obtain lower spatial resolution, synoptic coverage of the planet's surface and atmosphere. The cameras are based on the “push broom” technique; that is, they do not take “frames” but rather build pictures, one line at a time, as the spacecraft moves around the planet in its orbit. MOC is primarily a telescope f...

  9. Camera as Cultural Critique

    DEFF Research Database (Denmark)

    Suhr, Christian

    2015-01-01

    What does the use of cameras entail for the production of cultural critique in anthropology? Visual anthropological analysis and cultural critique starts at the very moment a camera is brought into the field or existing visual images are engaged. The framing, distances, and interactions between...... researchers, cameras, and filmed subjects already inherently comprise analytical decisions. It is these ethnographic qualities inherent in audiovisual and photographic imagery that make it of particular value to a participatory anthropological enterprise that seeks to resist analytic closure and seeks instead...

  10. The resistance of cocoa hybrids to vascular-streak dieback

    Directory of Open Access Journals (Sweden)

    Agung Wahyu Soesilo

    2011-08-01

    Full Text Available Breeding for VSD resistance on cocoa was carried out by inter-crossing the selected clones of TSH 858, KW 162, KW 163, KW 165, KEE 2, ICS 13 and NIC 7 which were selected based on the criteria of VSD resistance, productivity and cross-compatibility. This research has objective to evaluate hybrids of the crossess for VSD resistance, inheritance of the resistance and selecting the most valuable parental-clones for further crossess. Fourteen hybrids and one control were tested 14 in the randomized-completely block design with 4 blocks where in each plot 16 trees planted at Kaliwining Experimental Station in Jember. The resistance was evaluated in the field by scoring the symptoms in the range of 0—6 at 7 year after planting. The scores were varied significantly among the hybrids in the range of 2.19—4.53. Hybrids which were generated from the crosses of resistant clones performed lower number of the score than the hybrids generated from crosses between two susceptible clones (TSH 858 x NIC 7 which performed highest score. The hybrids classified as resistant were TSH 858 x KW 162 (F1 and reciprocal, KW 162 x KEE 2 (F1 and reciprocal, KW 162 x ICS 13, KW 165 x KEE 2. Of the parental clones, KW 162 is the most promising parent as lower score obtained when used it as male or female compared to KEE 2 which performed quite similar of the score with TSH 858 as susceptible parent. Therefore, it could be supposed that KW 162 has better combining ability than KEE 2 where these resistant-clones showed different segregation of their resistance. The resistance was segregated by KW 162 in term of ratio 15 resistant : 1 susceptible while KEE 2 the ratio 1 resistant: 1 susceptible.Key words: Theobroma cocoa L., hybrid, resistance, vascular-streak dieback.

  11. Advanced CCD camera developments

    Energy Technology Data Exchange (ETDEWEB)

    Condor, A. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    Two charge coupled device (CCD) camera systems are introduced and discussed, describing briefly the hardware involved, and the data obtained in their various applications. The Advanced Development Group Defense Sciences Engineering Division has been actively designing, manufacturing, fielding state-of-the-art CCD camera systems for over a decade. These systems were originally developed for the nuclear test program to record data from underground nuclear tests. Today, new and interesting application for these systems have surfaced and development is continuing in the area of advanced CCD camera systems, with the new CCD camera that will allow experimenters to replace film for x-ray imaging at the JANUS, USP, and NOVA laser facilities.

  12. TARGETLESS CAMERA CALIBRATION

    Directory of Open Access Journals (Sweden)

    L. Barazzetti

    2012-09-01

    Full Text Available In photogrammetry a camera is considered calibrated if its interior orientation parameters are known. These encompass the principal distance, the principal point position and some Additional Parameters used to model possible systematic errors. The current state of the art for automated camera calibration relies on the use of coded targets to accurately determine the image correspondences. This paper presents a new methodology for the efficient and rigorous photogrammetric calibration of digital cameras which does not require any longer the use of targets. A set of images depicting a scene with a good texture are sufficient for the extraction of natural corresponding image points. These are automatically matched with feature-based approaches and robust estimation techniques. The successive photogrammetric bundle adjustment retrieves the unknown camera parameters and their theoretical accuracies. Examples, considerations and comparisons with real data and different case studies are illustrated to show the potentialities of the proposed methodology.

  13. The evolution of amniote gastrulation: the blastopore-primitive streak transition.

    Science.gov (United States)

    Stower, Matthew J; Bertocchini, Federica

    2017-03-01

    In the animal kingdom, gastrulation, the process by which the primary germ layers are formed involves a dramatic transformation in the topology of the cells that give rise to all of the tissues of the adult. Initially formed as a mono-layer, this tissue, the epiblast, becomes subdivided through the internalization of cells, thereby forming a two (bi-laminar) or three (tri-laminar) layered embryo. This morphogenetic process coordinates the development of the fundamental body plan and the three-body axes (antero-posterior, dorso-ventral, and left-right) and begins a fundamental segregation of cells toward divergent developmental fates. In humans and other mammals, as well as in avians, gastrulating cells internalize along a structure, called the primitive streak, which builds from the periphery toward the center of the embryo. How these morphogenetic movements are orchestrated and evolved has been a question for developmental biologists for many years. Is the primitive streak a feature shared by the whole amniote clade? Insights from reptiles suggest that the primitive streak arose independently in mammals and avians, while the reptilian internalization site is a structure half-way between an amphibian blastopore and a primitive streak. The molecular machinery driving primitive streak formation has been partially dissected using mainly the avian embryo, revealing a paramount role of the planar cell polarity (PCP) pathway in streak formation. How did the employment of this machinery evolve? The reptilian branch of the amniote clade might provide us with useful tools to investigate the evolution of the amniote internalization site up to the formation of the primitive streak. WIREs Dev Biol 2017, 6:e262. doi: 10.1002/wdev.262 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

  14. Neutron cameras for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L.C.; Barnes, C.W.; Batistoni, P. [ITER San Diego Joint Work Site, La Jolla, CA (United States)] [and others

    1998-12-31

    Neutron cameras with horizontal and vertical views have been designed for ITER, based on systems used on JET and TFTR. The cameras consist of fan-shaped arrays of collimated flight tubes, with suitably chosen detectors situated outside the biological shield. The sight lines view the ITER plasma through slots in the shield blanket and penetrate the vacuum vessel, cryostat, and biological shield through stainless steel windows. This paper analyzes the expected performance of several neutron camera arrangements for ITER. In addition to the reference designs, the authors examine proposed compact cameras, in which neutron fluxes are inferred from {sup 16}N decay gammas in dedicated flowing water loops, and conventional cameras with fewer sight lines and more limited fields of view than in the reference designs. It is shown that the spatial sampling provided by the reference designs is sufficient to satisfy target measurement requirements and that some reduction in field of view may be permissible. The accuracy of measurements with {sup 16}N-based compact cameras is not yet established, and they fail to satisfy requirements for parameter range and time resolution by large margins.

  15. The sedimentology and dynamics of crater-affiliated wind streaks in western Arabia Terra, Mars and Patagonia, Argentina

    Science.gov (United States)

    Rodriguez, J.A.P.; Tanaka, K.L.; Yamamoto, A.; Berman, D.C.; Zimbelman, J.R.; Kargel, J.S.; Sasaki, S.; Jinguo, Y.; Miyamoto, H.

    2010-01-01

    Wind streaks comprise recent aeolian deposits that have been extensively documented on Venus, Earth and Mars. Martian wind streaks are among the most abundant surface features on the planet and commonly extend from the downwind margins of impact craters. Previous studies of wind streaks emerging from crater interior deposits suggested that the mode of emplacement was primarily related to the deposition of silt-sized particles as these settled from plumes. We have performed geologic investigations of two wind streaks clusters; one situated in western Arabia Terra, a region in the northern hemisphere of Mars, and another in an analogous terrestrial site located in southern Patagonia, Argentina, where occurrences of wind streaks emanate from playas within maar craters. In both these regions we have identified bedforms in sedimentary deposits on crater floors, along wind-facing interior crater margins, and along wind streaks. These observations indicate that these deposits contain sand-sized particles and that sediment migration has occurred via saltation from crater interior deposits to wind streaks. In Arabia Terra and in Patagonia wind streaks initiate from crater floors that contain lithic and evaporitic sedimentary deposits, suggesting that the composition of wind streak source materials has played an important role in development. Spatial and topographic analyses suggest that regional clustering of wind streaks in the studied regions directly correlates to the areal density of craters with interior deposits, the degree of proximity of these deposits, and the craters' rim-to-floor depths. In addition, some (but not all) wind streaks within the studied clusters have propagated at comparable yearly (Earth years) rates. Extensive saltation is inferred to have been involved in its propagation based on the studied terrestrial wind streak that shows ripples and dunes on its surface and the Martian counterpart changes orientation toward the downslope direction where it

  16. Detection, Occurrence, and Survey of Rice Stripe and Black-Streaked Dwarf Diseases in Zhejiang Province, China

    Directory of Open Access Journals (Sweden)

    Heng-mu ZHANG

    2013-11-01

    Full Text Available The major viral diseases that occur on rice plants in Zhejiang Province, eastern China, are stripe and rice black-streaked dwarf diseases. Rice stripe disease is only caused by rice stripe tenuivirus (RSV, while rice black-streaked dwarf disease can be caused by rice black-streaked dwarf fijivirus (RBSDV and/or southern rice black-streaked dwarf fijivirus (SRBSDV. Here we review the characterization of these viruses, methods for their detection, and extensive surveys showing their occurrence and spread in the province.

  17. Automated Streak Detection for High Velocity Objects: Test with YSTAR-NEOPAT Images

    Directory of Open Access Journals (Sweden)

    Dae-Won Chung

    2005-12-01

    Full Text Available We developed an algorithm to efficiently detect streaks in survey images and made a performance test with YSTAR-NEOPAT images obtained by the 0.5m telescope stationed in South Africa. Fast moving objects whose apparent speeds exceed 10 arcsec/min are the main target of our algorithm; these include artificial satellites, space debris, and very fast Near-Earth Objects. Our algorithm, based on the outline shape of elongated sources employs a step of image subtraction in order to reduce the confusion caused by dense distribution of faint stars. It takes less than a second to find and characterize streaks present in normal astronomical images of 2K format. Comparison with visual inspection proves the efficiency and completeness of our automated detection algorithm. When applied to about 7,000 time-series images from YSTAR telescope, nearly 700 incidents of streaks are detected. Fast moving objects are identified by the presence of matching streaks in adjoining frames. Nearly all of confirmed fast moving objects turn out to be artificial satellites or space debris. Majority of streaks are however meteors and cosmic ray hits, whose identity is often difficult to classify.

  18. The origin and structure of streak-like instabilities in laminar boundary layer flames

    Science.gov (United States)

    Gollner, Michael; Miller, Colin; Tang, Wei; Finney, Mark

    2017-11-01

    Streamwise streaks are consistently observed in wildland fires, at the base of pool fires, and in other heated flows within a boundary layer. This study examines both the origin of these structures and their role in influencing some of the macroscopic properties of the flow. Streaks were reproduced and characterized via experiments on stationary heated strips and liquid and gas-fueled burners in laminar boundary layer flows, providing a framework to develop theory based on both observed and measured physical phenomena. The incoming boundary layer was established as the controlling mechanism in forming streaks, which are generated by pre-existing coherent structures, while the amplification of streaks was determined to be compatible with quadratic growth of Rayleigh-Taylor Instabilities, providing credence to the idea that the downstream growth of streaks is strongly tied to buoyancy. These local instabilities were also found to affect macroscopic properties of the flow, including heat transfer to the surface, indicating that a two-dimensional assumption may fail to adequately describe heat and mass transfer during flame spread and other reacting boundary layer flows. This work was supported by NSF (CBET-1554026) and the USDA-FS (13-CS-11221637-124).

  19. Transient energy growth of optimal streaks in parallel round jets

    Science.gov (United States)

    Jiménez-González, J. I.; Brancher, P.

    2017-11-01

    We present a linear optimal perturbation analysis of streamwise invariant disturbances evolving in parallel round jets. The potential for transient energy growth of perturbations with azimuthal wavenumber m ≥1 is analyzed for different values of Reynolds number R e . Two families of steady (frozen) and unsteady (diffusing) base flow velocity profiles have been used, for different aspect ratios α = R/θ, where R is the jet radius and θ is the shear layer momentum thickness. Optimal initial conditions correspond to infinitesimal streamwise vortices, which evolve transiently to produce axial velocity streaks, whose spatial structure and intensity depend on base flow and perturbation parameters. Their dynamics can be characterized by a maximum optimal value of the energy gain Gopt, reached at an optimal time τopt after which the perturbations eventually decay. Optimal energy gain and time are shown to be, respectively, proportional to R e2 and R e , regardless of the frozen or diffusing nature of the base flow. Besides, it is found that the optimal gain scales like Go p t∝1 /m3 for all m except m = 1. This quantitative difference for azimuthal wavenumber m = 1 is shown to be based on the nature of transient mechanisms. For m = 1 perturbations, the shift-up effect [J. I. Jiménez-González et al., "Modal and non-modal evolution of perturbations for parallel round jets," Phys. Fluids 27, 044105-1-044105-19 (2015)] is active: an initial streamwise vorticity dipole induces a nearly uniform velocity flow in the jet core, which shifts the whole jet radially. By contrast, optimal perturbations with m ≥2 are concentrated along the shear layer, in a way that resembles the classical lift-up mechanism in wall-shear flows. The m = 1 shift-up effect is more energetic than the m ≥2 lift-up, but it is slower, with optimal times considerably shorter in the case of m ≥2 disturbances. This suggests that these perturbations may emerge very quickly in the flow when injected

  20. The VISTA IR camera

    Science.gov (United States)

    Dalton, Gavin B.; Caldwell, Martin; Ward, Kim; Whalley, Martin S.; Burke, Kevin; Lucas, John M.; Richards, Tony; Ferlet, Marc; Edeson, Ruben L.; Tye, Daniel; Shaughnessy, Bryan M.; Strachan, Mel; Atad-Ettedgui, Eli; Leclerc, Melanie R.; Gallie, Angus; Bezawada, Nagaraja N.; Clark, Paul; Bissonauth, Nirmal; Luke, Peter; Dipper, Nigel A.; Berry, Paul; Sutherland, Will; Emerson, Jim

    2004-09-01

    The VISTA IR Camera has now completed its detailed design phase and is on schedule for delivery to ESO"s Cerro Paranal Observatory in 2006. The camera consists of 16 Raytheon VIRGO 2048x2048 HgCdTe arrays in a sparse focal plane sampling a 1.65 degree field of view. A 1.4m diameter filter wheel provides slots for 7 distinct science filters, each comprising 16 individual filter panes. The camera also provides autoguiding and curvature sensing information for the VISTA telescope, and relies on tight tolerancing to meet the demanding requirements of the f/1 telescope design. The VISTA IR camera is unusual in that it contains no cold pupil-stop, but rather relies on a series of nested cold baffles to constrain the light reaching the focal plane to the science beam. In this paper we present a complete overview of the status of the final IR Camera design, its interaction with the VISTA telescope, and a summary of the predicted performance of the system.

  1. Commercialization of radiation tolerant camera

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Bum; Choi, Young Soo; Kim, Sun Ku; Lee, Jong Min; Cha, Bung Hun; Lee, Nam Ho; Byun, Eiy Gyo; Yoo, Seun Wook; Choi, Bum Ki; Yoon, Sung Up; Kim, Hyun Gun; Sin, Jeong Hun; So, Suk Il

    1999-12-01

    In this project, radiation tolerant camera which tolerates 10{sup 6} - 10{sup 8} rad total dose is developed. In order to develop radiation tolerant camera, radiation effect of camera components was examined and evaluated, and camera configuration was studied. By the result of evaluation, the components were decided and design was performed. Vidicon tube was selected to use by image sensor and non-browning optics and camera driving circuit were applied. The controller needed for CCTV camera system, lens, light, pan/tilt controller, was designed by the concept of remote control. And two type of radiation tolerant camera were fabricated consider to use in underwater environment or normal environment. (author)

  2. Ice fall streaks in a warm front . An S-band polarimetric radar study

    Science.gov (United States)

    Keppas, Stavros; Crosier, Jonathan; Choularton, Thomas; Bower, Keith

    2017-04-01

    On 21st January 2009, a maturing low pressure system approached the UK along with several associated systems. An observational research flight (part of the APPRAISE-Clouds project) took place in southern England, sampling the leading warm front of this system. During the flight, the Warm Conveyor Belt (WCB) was well depicted by the radar Doppler velocity parameter. Simultaneously, extensive ice fall streaks appeared on ZDR RHI scans as long slanted zones of high ZDR. It seems that there is a connection between the WCB activity and the formation and structure of the ice fall streaks. The Kelvin-Helmholtz instability caused by the WCB played a key role on their formation. Moreover, in-situ measurements showed that the ice fall streaks had a very specific substance and they can affect the surface precipitation.

  3. HIGH SPEED CAMERA

    Science.gov (United States)

    Rogers, B.T. Jr.; Davis, W.C.

    1957-12-17

    This patent relates to high speed cameras having resolution times of less than one-tenth microseconds suitable for filming distinct sequences of a very fast event such as an explosion. This camera consists of a rotating mirror with reflecting surfaces on both sides, a narrow mirror acting as a slit in a focal plane shutter, various other mirror and lens systems as well as an innage recording surface. The combination of the rotating mirrors and the slit mirror causes discrete, narrow, separate pictures to fall upon the film plane, thereby forming a moving image increment of the photographed event. Placing a reflecting surface on each side of the rotating mirror cancels the image velocity that one side of the rotating mirror would impart, so as a camera having this short a resolution time is thereby possible.

  4. Wide angle pinhole camera

    Science.gov (United States)

    Franke, J. M.

    1978-01-01

    Hemispherical refracting element gives pinhole camera 180 degree field-of-view without compromising its simplicity and depth-of-field. Refracting element, located just behind pinhole, bends light coming in from sides so that it falls within image area of film. In contrast to earlier pinhole cameras that used water or other transparent fluids to widen field, this model is not subject to leakage and is easily loaded and unloaded with film. Moreover, by selecting glass with different indices of refraction, field at film plane can be widened or reduced.

  5. Automatic Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Preuss, Mike

    2014-01-01

    camera. We approach this problem by modelling it as a dynamic multi-objective optimisation problem and show how this metaphor allows a much richer expressiveness than a classical single objective approach. Finally, we showcase the application of a multi-objective evolutionary algorithm to generate a shot...

  6. Make a Pinhole Camera

    Science.gov (United States)

    Fisher, Diane K.; Novati, Alexander

    2009-01-01

    On Earth, using ordinary visible light, one can create a single image of light recorded over time. Of course a movie or video is light recorded over time, but it is a series of instantaneous snapshots, rather than light and time both recorded on the same medium. A pinhole camera, which is simple to make out of ordinary materials and using ordinary…

  7. The canopy camera

    Science.gov (United States)

    Harry E. Brown

    1962-01-01

    The canopy camera is a device of new design that takes wide-angle, overhead photographs of vegetation canopies, cloud cover, topographic horizons, and similar subjects. Since the entire hemisphere is photographed in a single exposure, the resulting photograph is circular, with the horizon forming the perimeter and the zenith the center. Photographs of this type provide...

  8. MISR radiometric camera-by-camera Cloud Mask V004

    Data.gov (United States)

    National Aeronautics and Space Administration — This file contains the Radiometric camera-by-camera Cloud Mask dataset. It is used to determine whether a scene is classified as clear or cloudy. A new parameter has...

  9. Goniometer to calibrate system cameras or amateur cameras

    Science.gov (United States)

    Hakkarainen, J.

    An accurate and rapid horizontal goniometer was developed to determine the optical properties of film cameras. Radial and decentering distortion, color defects, optical resolution, and small object transmission factors are measured according to light wavelengths and symmetry. The goniometer can be used to calibrate cameras for photogrammetry, to determine the effects of remoteness on image geometry, distortion symmetry, efficiency of lens lighting film systems, to develop quality criteria for lenses, and to test camera lens and camera defects after an incident.

  10. Quantitative trait loci for resistance to maize streak virus disease in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... characterized quantitative trait loci affecting resistance to maize streak virus in maize populations of S4 families from the cross of one resistant MAL13 and one susceptible MAL9 recombinant inbred lines. Resistance was evaluated in replicated field trials under artificial inoculation while selecting using.

  11. Evaluation of banana hybrids for tolerance to black leaf streak (Mycosphaerella fijiensis Morelet) in Puerto Rico

    Science.gov (United States)

    In Puerto Rico, bananas (including plantains) are important agricultural commodities; their combined production totaled 133,500 tons in 2008. Black leaf streak (BLS) and Sigatoka leaf spot diseases, caused by Mycosphaerella fijiensis and M. musicola, respectively, are responsible for significant los...

  12. Characteristics of the alarm calls of buff-streaked chat groups and ...

    African Journals Online (AJOL)

    Many animals emit alarm calls in response to a potential predator. These calls may transmit information about predator type and response urgency. This study compared the alarm calls of the social buff-streaked chat, Oenanthe bifasciata, to the asocial African stonechat, Saxicola torquata. Spring traps were used to capture ...

  13. Efficient inoculation of rice black-streaked dwarf virus to maize using Laodelphax striatellus Fallen

    Science.gov (United States)

    Maize rough dwarf disease (MRDD) caused by Rice black-streaked dwarf virus (RBSDV) is the most important viral disease of maize in China. Although deploying disease resistant hybrids would be the most effective way to control the disease, development of resistant hybrids has been limited by virus t...

  14. Diversity of banana streak-inducing viruses in Nigeria and Ghana ...

    African Journals Online (AJOL)

    GRACE

    2006-06-16

    Jun 16, 2006 ... revealed BSV-like particles by IEM than were detected by TAS-ELISA or IC-PCR. Of the 51 leaf ... BSV-like viruses in West Africa. Key words: Banana streak virus, diversity, serological assays, immunoelectron microscopy, immunocapture. PCR. ..... inclination between their arms were also frequently.

  15. Multiplex Real Time PCR For Detection of Wheat Streak Mosaic Virus and Triticum Mosaic Virus

    Science.gov (United States)

    Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TRIMV) are widespread throughout the southwestern Great Plains states. Using conventional diagnostics such as Enzyme-Linked Immunosorbent Assays (ELISA), these two viruses are commonly found together in infected wheat samples. Methods for m...

  16. Pathophysiological consideration of medullary streaks on FLAIR imaging in pediatric moyamoya disease.

    Science.gov (United States)

    Suzuki, Hime; Mikami, Takeshi; Kuribara, Tomoyoshi; Yoshifuji, Kazuhisa; Komatsu, Katsuya; Akiyama, Yukinori; Ohnishi, Hirofumi; Houkin, Kiyohiro; Mikuni, Nobuhiro

    2017-05-01

    OBJECTIVE Medullary streaks detected on fluid-attenuated inversion recovery (FLAIR) imaging have been considered to be reflected ischemic regions in pediatric moyamoya disease. The purpose of this study was to evaluate these medullary streaks both clinically and radiologically and to discuss associated pathophysiological concerns. METHODS The authors retrospectively reviewed data from 14 consecutive pediatric patients with moyamoya disease treated between April 2009 and June 2016. Clinical and radiological features and postoperative imaging changes were analyzed. In 4 patients, hyperintense medullary streaks on FLAIR imaging (HMSF) at the level of the centrum semiovale were detected. RESULTS The HMSF were coincident with hyperintense medullary streaks on a T2-weighted image, though they were not completely coincident with the vasculature on either a T2*-weighted image or contrast-enhanced CT. Analysis revealed significantly higher values in terms of MR angiography scores, number of flow voids of the basal ganglia, and the presence of the medullary artery in the group with HMSF than in those without. In contrast, the presence of white matter damage was significantly less frequent in the HMSF group. All HMSF disappeared after surgery, and the mean apparent diffusion coefficient at the same level was significantly reduced postoperatively. CONCLUSIONS Although HMSF should be associated with collateral circulation in moyamoya disease, other factors may be involved, including stagnated cerebrospinal fluid or vasogenic edema that is relevant to the impaired state of the white matter. Findings in this study provide insight into the pathophysiological basis of the perivascular space in moyamoya disease.

  17. Attosecond streaking of shake-up and Auger electrons in xenon

    Directory of Open Access Journals (Sweden)

    Drescher M.

    2013-03-01

    Full Text Available We present first results of simultaneous attosecond streaking measurements of shake-up electrons and Auger electrons emitted from xenon. We extract relative photo-emission delays for electrons emitted from the 4d, 5s and 5p subshell, as well as for the 5p−25d correlation satellite (shake-up electrons.

  18. Diversity of banana streak-inducing viruses in Nigeria and Ghana ...

    African Journals Online (AJOL)

    GRACE

    2006-06-16

    Jun 16, 2006 ... populations or showing an angularly bent morphology were found. Occasionally, in certain samples and with ... Australia was determined by sequence comparison of the conserved sequence motifs of the ...... Genetic diversity among Banana streak virus isolates from Australia. Phytopathol. 90: 921-927.

  19. Effect of temperature on wheat streak mosaic disease development in winter wheat

    Science.gov (United States)

    Temperature is one of the key factors that influence viral disease development in plants. In this study, temperature effect on Wheat streak mosaic virus (WSMV) replication and in planta movement was determined using a green fluorescent protein (GFP)-tagged virus in two winter wheat cultivars. Virus-...

  20. Chromatin Structure of Wheat Breeding Lines Resistant to Wheat Streak Mosaic Virus.

    Science.gov (United States)

    Wheat Streak Mosaic Virus (WSMV) is an important disease limiting wheat production, however no WSMV resistance effective above 18°C is present within the primary genetic pool of wheat (Triticum aestivum L.). In contrast, the wild relative Thinopyrum intermedium (2n=6x=42) shows good resistance to WS...

  1. Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

    Science.gov (United States)

    Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

    2015-04-01

    For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

  2. Body worn camera

    Science.gov (United States)

    Aishwariya, A.; Pallavi Sudhir, Gulavani; Garg, Nemesa; Karthikeyan, B.

    2017-11-01

    A body worn camera is small video camera worn on the body, typically used by police officers to record arrests, evidence from crime scenes. It helps preventing and resolving complaints brought by members of the public; and strengthening police transparency, performance, and accountability. The main constants of this type of the system are video format, resolution, frames rate, and audio quality. This system records the video in .mp4 format with 1080p resolution and 30 frames per second. One more important aspect to while designing this system is amount of power the system requires as battery management becomes very critical. The main design challenges are Size of the Video, Audio for the video. Combining both audio and video and saving it in .mp4 format, Battery, size that is required for 8 hours of continuous recording, Security. For prototyping this system is implemented using Raspberry Pi model B.

  3. The NEAT Camera Project

    Science.gov (United States)

    Jr., Ray L. Newburn

    1995-01-01

    The NEAT (Near Earth Asteroid Tracking) camera system consists of a camera head with a 6.3 cm square 4096 x 4096 pixel CCD, fast electronics, and a Sun Sparc 20 data and control computer with dual CPUs, 256 Mbytes of memory, and 36 Gbytes of hard disk. The system was designed for optimum use with an Air Force GEODSS (Ground-based Electro-Optical Deep Space Surveillance) telescope. The GEODSS telescopes have 1 m f/2.15 objectives of the Ritchey-Chretian type, designed originally for satellite tracking. Installation of NEAT began July 25 at the Air Force Facility on Haleakala, a 3000 m peak on Maui in Hawaii.

  4. Visual odometry from omnidirectional camera

    OpenAIRE

    Jiří DIVIŠ

    2012-01-01

    We present a system that estimates the motion of a robot relying solely on images from onboard omnidirectional camera (visual odometry). Compared to other visual odometry hardware, ours is unusual in utilizing high resolution, low frame-rate (1 to 3 Hz) omnidirectional camera mounted on a robot that is propelled using continuous tracks. We focus on high precision estimates in scenes, where objects are far away from the camera. This is achieved by utilizing omnidirectional camera that is able ...

  5. Gamma ray camera

    Science.gov (United States)

    Perez-Mendez, Victor

    1997-01-01

    A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array.

  6. The DRAGO gamma camera.

    Science.gov (United States)

    Fiorini, C; Gola, A; Peloso, R; Longoni, A; Lechner, P; Soltau, H; Strüder, L; Ottobrini, L; Martelli, C; Lui, R; Madaschi, L; Belloli, S

    2010-04-01

    In this work, we present the results of the experimental characterization of the DRAGO (DRift detector Array-based Gamma camera for Oncology), a detection system developed for high-spatial resolution gamma-ray imaging. This camera is based on a monolithic array of 77 silicon drift detectors (SDDs), with a total active area of 6.7 cm(2), coupled to a single 5-mm-thick CsI(Tl) scintillator crystal. The use of an array of SDDs provides a high quantum efficiency for the detection of the scintillation light together with a very low electronics noise. A very compact detection module based on the use of integrated readout circuits was developed. The performances achieved in gamma-ray imaging using this camera are reported here. When imaging a 0.2 mm collimated (57)Co source (122 keV) over different points of the active area, a spatial resolution ranging from 0.25 to 0.5 mm was measured. The depth-of-interaction capability of the detector, thanks to the use of a Maximum Likelihood reconstruction algorithm, was also investigated by imaging a collimated beam tilted to an angle of 45 degrees with respect to the scintillator surface. Finally, the imager was characterized with in vivo measurements on mice, in a real preclinical environment.

  7. Hemispherical Laue camera

    Science.gov (United States)

    Li, James C. M.; Chu, Sungnee G.

    1980-01-01

    A hemispherical Laue camera comprises a crystal sample mount for positioning a sample to be analyzed at the center of sphere of a hemispherical, X-radiation sensitive film cassette, a collimator, a stationary or rotating sample mount and a set of standard spherical projection spheres. X-radiation generated from an external source is directed through the collimator to impinge onto the single crystal sample on the stationary mount. The diffracted beam is recorded on the hemispherical X-radiation sensitive film mounted inside the hemispherical film cassette in either transmission or back-reflection geometry. The distances travelled by X-radiation diffracted from the crystal to the hemispherical film are the same for all crystal planes which satisfy Bragg's Law. The recorded diffraction spots or Laue spots on the film thereby preserve both the symmetry information of the crystal structure and the relative intensities which are directly related to the relative structure factors of the crystal orientations. The diffraction pattern on the exposed film is compared with the known diffraction pattern on one of the standard spherical projection spheres for a specific crystal structure to determine the orientation of the crystal sample. By replacing the stationary sample support with a rotating sample mount, the hemispherical Laue camera can be used for crystal structure determination in a manner previously provided in conventional Debye-Scherrer cameras.

  8. POD analysis of the instability mode of a low-speed streak in a laminar boundary layer

    Science.gov (United States)

    Deng, Si-Chao; Pan, Chong; Wang, Jin-Jun; Rinoshika, Akira

    2017-12-01

    The instability of one single low-speed streak in a zero-pressure-gradient laminar boundary layer is investigated experimentally via both hydrogen bubble visualization and planar particle image velocimetry (PIV) measurement. A single low-speed streak is generated and destabilized by the wake of an interference wire positioned normal to the wall and in the upstream. The downstream development of the streak includes secondary instability and self-reproduction process, which leads to the generation of two additional streaks appearing on either side of the primary one. A proper orthogonal decomposition (POD) analysis of PIV measured velocity field is used to identify the components of the streak instability in the POD mode space: for a sinuous/varicose type of POD mode, its basis functions present anti-symmetric/symmetric distributions about the streak centerline in the streamwise component, and the symmetry condition reverses in the spanwise component. It is further shown that sinuous mode dominates the turbulent kinematic energy (TKE) through the whole streak evolution process, the TKE content first increases along the streamwise direction to a saturation value and then decays slowly. In contrast, varicose mode exhibits a sustained growth of the TKE content, suggesting an increasing competition of varicose instability against sinuous instability.

  9. POD analysis of the instability mode of a low-speed streak in a laminar boundary layer

    Science.gov (United States)

    Deng, Si-Chao; Pan, Chong; Wang, Jin-Jun; Rinoshika, Akira

    2017-06-01

    The instability of one single low-speed streak in a zero-pressure-gradient laminar boundary layer is investigated experimentally via both hydrogen bubble visualization and planar particle image velocimetry (PIV) measurement. A single low-speed streak is generated and destabilized by the wake of an interference wire positioned normal to the wall and in the upstream. The downstream development of the streak includes secondary instability and self-reproduction process, which leads to the generation of two additional streaks appearing on either side of the primary one. A proper orthogonal decomposition (POD) analysis of PIV measured velocity field is used to identify the components of the streak instability in the POD mode space: for a sinuous/varicose type of POD mode, its basis functions present anti-symmetric/symmetric distributions about the streak centerline in the streamwise component, and the symmetry condition reverses in the spanwise component. It is further shown that sinuous mode dominates the turbulent kinematic energy (TKE) through the whole streak evolution process, the TKE content first increases along the streamwise direction to a saturation value and then decays slowly. In contrast, varicose mode exhibits a sustained growth of the TKE content, suggesting an increasing competition of varicose instability against sinuous instability.

  10. A Demographic Model to Evaluate Population Declines in the Endangered Streaked Horned Lark

    Directory of Open Access Journals (Sweden)

    Alaine F. Camfield

    2011-12-01

    Full Text Available The Streaked Horned Lark (Eremophila alpestris strigata is listed as endangered by the State of Washington, USA and by Canada under the Species at Risk Act and is also classified as a federal candidate for listing under the Endangered Species Act in the USA. A substantial portion of Streaked Horned Lark habitat has been lost or degraded, and range contraction has occurred in Oregon, Washington, and British Columbia. We estimate the vital rates (fecundity, adult and juvenile survival and population growth rate (λ for Streaked Horned Larks breeding in Washington, USA and conduct a Life-Stage Simulation Analysis (LSA to evaluate which vital rate has the greatest influence on λ. We simulated changes in the three vital rates to examine how much they would need to be adjusted either independently or in concert to achieve a stable Streaked Horned Lark population (λ = 1. We also evaluated which fecundity component (the number of fledglings per egg laid or renesting interval had the greatest impact on λ. The estimate of population growth suggests that Streaked Horned Larks in Washington are declining rapidly (λ = 0.62 ± 0.10 and that local breeding sites are not sustainable without immigration. The LSA results indicate that adult survival had the greatest influence on λ, followed by juvenile survival and fecundity. However, increases in vital rates led to λ = 1 only when adult survival was raised from 0.47 to 0.85, juvenile survival from 0.17 to 0.58, and fecundity from 0.91 to 3.09. Increases in breeding success and decreases in the renesting interval influenced λ similarly; however, λ did not reach 1 even when breeding success was raised to 100% or renesting intervals were reduced to 1 day. Only when all three vital rates were increased simultaneously did λ approach 1 without requiring highly unrealistic increases in each vital rate. We conclude that conservation activities need to target all or multiple vital rates to be successful. The

  11. Three-dimensional camera

    Science.gov (United States)

    Bothe, Thorsten; Gesierich, Achim; Legarda-Saenz, Ricardo; Jueptner, Werner P. O.

    2003-05-01

    Industrial- and multimedia applications need cost effective, compact and flexible 3D profiling instruments. In the talk we will show the principle of, applications for and results from a new miniaturized 3-D profiling system for macroscopic scenes. The system uses a compact housing and is usable like a camera with minimum stabilization like a tripod. The system is based on common fringe projection technique. Camera and projector are assembled with parallel optical axes having coplanar projection and imaging plane. Their axes distance is comparable to the human eyes distance altogether giving a complete system of 21x20x11 cm size and allowing to measure high gradient objects like the interior of tubes. The fringe projector uses a LCD which enables fast and flexible pattern projection. Camera and projector have a short focal length and a high system aperture as well as a large depth of focus. Thus, objects can be measured from a shorter distance compared to common systems (e.g. 1 m sized objects in 80 cm distance). Actually, objects with diameters up to 4 m can be profiled because the set-up allows working with completely opened aperture combined with bright lamps giving a big amount of available light and a high Signal to Noise Ratio. Normally a small basis has the disadvantage of reduced sensitivity. We investigated in methods to compensate the reduced sensitivity via setup and enhanced evaluation methods. For measurement we use synthetic wavelengths. The developed algorithms are completely adaptable concerning the users needs of speed and accuracy. The 3D camera is built from low cost components, robust, nearly handheld and delivers insights also into difficult technical objects like tubes and inside volumes. Besides the realized high resolution phase measurement the system calibration is an important task for usability. While calibrating with common photogrammetric models (which are typically used for actual fringe projection systems) problems were found that

  12. Digital camera in ophthalmology

    Directory of Open Access Journals (Sweden)

    Ashish Mitra

    2015-01-01

    Full Text Available Ophthalmology is an expensive field and imaging is an indispensable modality in ophthalmology; and in developing countries including India, it is not possible for every ophthalmologist to afford slit-lamp photography unit. We here present our experience of slit-lamp photography using digital camera. Good quality pictures of anterior and posterior segment disorders were captured using readily available devices. It can be a used as a good teaching tool for residents learning ophthalmology and can also be a method to document lesions which at many times is necessary for medicolegal purposes. It's a technique which is simple, inexpensive, and has a short learning curve.

  13. NFC - Narrow Field Camera

    Science.gov (United States)

    Koukal, J.; Srba, J.; Gorková, S.

    2015-01-01

    We have been introducing a low-cost CCTV video system for faint meteor monitoring and here we describe the first results from 5 months of two-station operations. Our system called NFC (Narrow Field Camera) with a meteor limiting magnitude around +6.5mag allows research on trajectories of less massive meteoroids within individual parent meteor showers and the sporadic background. At present 4 stations (2 pairs with coordinated fields of view) of NFC system are operated in the frame of CEMeNt (Central European Meteor Network). The heart of each NFC station is a sensitive CCTV camera Watec 902 H2 and a fast cinematographic lens Meopta Meostigmat 1/50 - 52.5 mm (50 mm focal length and fixed aperture f/1.0). In this paper we present the first results based on 1595 individual meteors, 368 of which were recorded from two stations simultaneously. This data set allows the first empirical verification of theoretical assumptions for NFC system capabilities (stellar and meteor magnitude limit, meteor apparent brightness distribution and accuracy of single station measurements) and the first low mass meteoroid trajectory calculations. Our experimental data clearly showed the capabilities of the proposed system for low mass meteor registration and for calculations based on NFC data to lead to a significant refinement in the orbital elements for low mass meteoroids.

  14. Compact 3D camera

    Science.gov (United States)

    Bothe, Thorsten; Osten, Wolfgang; Gesierich, Achim; Jueptner, Werner P. O.

    2002-06-01

    A new, miniaturized fringe projection system is presented which has a size and handling that approximates to common 2D cameras. The system is based on the fringe projection technique. A miniaturized fringe projector and camera are assembled into a housing of 21x20x11 cm size with a triangulation basis of 10 cm. The advantage of the small triangulation basis is the possibility to measure difficult objects with high gradients. Normally a small basis has the disadvantage of reduced sensitivity. We investigated in methods to compensate the reduced sensitivity via setup and enhanced evaluation methods. Special hardware issues are a high quality, bright light source (and components to handle the high luminous flux) as well as adapted optics to gain a large aperture angle and a focus scan unit to increase the usable measurement volume. Adaptable synthetic wavelengths and integration times were used to increase the measurement quality and allow robust measurements that are adaptable to the desired speed and accuracy. Algorithms were developed to generate automatic focus positions to completely cover extended measurement volumes. Principles, setup, measurement examples and applications are shown.

  15. Mars Science Laboratory Engineering Cameras

    Science.gov (United States)

    Maki, Justin N.; Thiessen, David L.; Pourangi, Ali M.; Kobzeff, Peter A.; Lee, Steven W.; Dingizian, Arsham; Schwochert, Mark A.

    2012-01-01

    NASA's Mars Science Laboratory (MSL) Rover, which launched to Mars in 2011, is equipped with a set of 12 engineering cameras. These cameras are build-to-print copies of the Mars Exploration Rover (MER) cameras, which were sent to Mars in 2003. The engineering cameras weigh less than 300 grams each and use less than 3 W of power. Images returned from the engineering cameras are used to navigate the rover on the Martian surface, deploy the rover robotic arm, and ingest samples into the rover sample processing system. The navigation cameras (Navcams) are mounted to a pan/tilt mast and have a 45-degree square field of view (FOV) with a pixel scale of 0.82 mrad/pixel. The hazard avoidance cameras (Haz - cams) are body-mounted to the rover chassis in the front and rear of the vehicle and have a 124-degree square FOV with a pixel scale of 2.1 mrad/pixel. All of the cameras utilize a frame-transfer CCD (charge-coupled device) with a 1024x1024 imaging region and red/near IR bandpass filters centered at 650 nm. The MSL engineering cameras are grouped into two sets of six: one set of cameras is connected to rover computer A and the other set is connected to rover computer B. The MSL rover carries 8 Hazcams and 4 Navcams.

  16. Motion Streaks Do Not Influence the Perceived Position of Stationary Flashed Objects

    Directory of Open Access Journals (Sweden)

    Andrea Pavan

    2012-01-01

    Full Text Available In the present study, we investigated whether motion streaks, produced by fast moving dots Geisler 1999, distort the positional map of stationary flashed objects producing the well-known motion-induced position shift illusion (MIPS. The illusion relies on motion-processing mechanisms that induce local distortions in the positional map of the stimulus which is derived by shape-processing mechanisms. To measure the MIPS, two horizontally offset Gaussian blobs, placed above and below a central fixation point, were flashed over two fields of dots moving in opposite directions. Subjects judged the position of the top Gaussian blob relative to the bottom one. The results showed that neither fast (motion streaks nor slow moving dots influenced the perceived spatial position of the stationary flashed objects, suggesting that background motion does not interact with the shape-processing mechanisms involved in MIPS.

  17. Drag reduction of a 3D bluff body using coherent streamwise streaks

    Science.gov (United States)

    Pujals, G.; Depardon, S.; Cossu, C.

    2010-11-01

    Separation on the rear-end of an Ahmed body is suppressed by means of large-scale coherent streaks forced on the roof of the model. These streaks originate from an array of suitably shaped cylindrical roughness elements and are amplified by the mean shear through the lift-up effect. Interacting with the mean velocity field at leading order, they induce a strong controlled spanwise modulation. The resulting streaky base flow is observed to sustain the adverse pressure gradient since PIV measurements as well as static wall pressure distributions show that the re-circulation bubble completely vanishes. These modifications of the topology of the flow are associated with a substantial drag reduction, which can be of about 10% when the roughness array is optimally placed on the roof of the bluff body.

  18. Molecular characterization of banana streak acuminata Vietnam virus isolated from Musa acuminata siamea (banana cultivar).

    Science.gov (United States)

    Lheureux, F; Laboureau, N; Muller, E; Lockhart, B E L; Iskra-Caruana, M-L

    2007-01-01

    An isolate of banana streak virus (BSV) that does not also occur as an integrant in the Musa balbisiana genome was sought in order to investigate the biological role of BSV in the evolution of either the Musa genome or of the virus itself. We isolated BSV virions from a Musa acuminata siamea accession from Vietnam and sequenced the entire viral genome. The molecular organization is similar to that described for other BSV but slightly larger (7801 bp vs. 1611-7568 bp), and ORF I has a non-conventional start codon. This genome was sufficiently different to propose it as a member of a distinct species named Banana streak virus strain acuminata Vietnam (BSAcVNV).

  19. Motion Streaks Do Not Influence the Perceived Position of Stationary Flashed Objects

    Science.gov (United States)

    Pavan, Andrea; Bellacosa Marotti, Rosilari

    2012-01-01

    In the present study, we investigated whether motion streaks, produced by fast moving dots Geisler 1999, distort the positional map of stationary flashed objects producing the well-known motion-induced position shift illusion (MIPS). The illusion relies on motion-processing mechanisms that induce local distortions in the positional map of the stimulus which is derived by shape-processing mechanisms. To measure the MIPS, two horizontally offset Gaussian blobs, placed above and below a central fixation point, were flashed over two fields of dots moving in opposite directions. Subjects judged the position of the top Gaussian blob relative to the bottom one. The results showed that neither fast (motion streaks) nor slow moving dots influenced the perceived spatial position of the stationary flashed objects, suggesting that background motion does not interact with the shape-processing mechanisms involved in MIPS. PMID:22645464

  20. The effect of the acceleration/deceleration trauma in angioid streaks: A pathogenic hypothesis.

    Science.gov (United States)

    Fajardo Sánchez, J; Chau Ramos, C E; Mazagatos Used, P J; Aparicio Hernandez-Lastras, M J

    2016-09-01

    A 59-year-old male with acceleration/deceleration cranial trauma (ADT), caused by a car accident. After one month, he presented with loss of visual acuity in the right eye. A fluorescein angiography test was performed and it detected centrifugal hyperfluorescent lines from the optic nerve head, a characteristic compatible with the diagnosis of angioid streaks. The loss of visual acuity was demonstrated by the discovery of a juxtafoveal choroidal neovascular membrane (CNV). ADT can cause hyper-extension of the eyeball in its equator line, producing the rupture of fragile structures such as the Bruch membrane (MB) in patients with angioid streaks and the subsequent formation of CNV. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  1. ACCURACY EVALUATION OF STEREO CAMERA SYSTEMS WITH GENERIC CAMERA MODELS

    Directory of Open Access Journals (Sweden)

    D. Rueß

    2012-07-01

    Full Text Available In the last decades the consumer and industrial market for non-projective cameras has been growing notably. This has led to the development of camera description models other than the pinhole model and their employment in mostly homogeneous camera systems. Heterogeneous camera systems (for instance, combine Fisheye and Catadioptric cameras can also be easily thought of for real applications. However, it has not been quite clear, how accurate stereo vision with these cameras and models can be. In this paper, different accuracy aspects are addressed by analytical inspection, numerical simulation as well as real image data evaluation. This analysis is generic, for any camera projection model, although only polynomial and rational projection models are used for distortion free, Catadioptric and Fisheye lenses. Note that this is different to polynomial and rational radial distortion models which have been addressed extensively in literature. For single camera analysis it turns out that point features towards the image sensor borders are significantly more accurate than in center regions of the sensor. For heterogeneous two camera systems it turns out, that reconstruction accuracy decreases significantly towards image borders as different projective distortions occur.

  2. Optimally amplified large-scale streaks and drag reduction in turbulent pipe flow

    Science.gov (United States)

    Willis, Ashley P.; Hwang, Yongyun; Cossu, Carlo

    2010-09-01

    The optimal amplifications of small coherent perturbations within turbulent pipe flow are computed for Reynolds numbers up to one million. Three standard frameworks are considered: the optimal growth of an initial condition, the response to harmonic forcing and the Karhunen-Loève (proper orthogonal decomposition) analysis of the response to stochastic forcing. Similar to analyses of the turbulent plane channel flow and boundary layer, it is found that streaks elongated in the streamwise direction can be greatly amplified from quasistreamwise vortices, despite linear stability of the mean flow profile. The most responsive perturbations are streamwise uniform and, for sufficiently large Reynolds number, the most responsive azimuthal mode is of wave number m=1 . The response of this mode increases with the Reynolds number. A secondary peak, where m corresponds to azimuthal wavelengths λθ+≈70-90 in wall units, also exists in the amplification of initial conditions and in premultiplied response curves for the forced problems. Direct numerical simulations at Re=5300 confirm that the forcing of m=1,2 and m=4 optimal structures results in the large response of coherent large-scale streaks. For moderate amplitudes of the forcing, low-speed streaks become narrower and more energetic, whereas high-speed streaks become more spread. It is further shown that drag reduction can be achieved by forcing steady large-scale structures, as anticipated from earlier investigations. Here the energy balance is calculated. At Re=5300 it is shown that, due to the small power required by the forcing of optimal structures, a net power saving of the order of 10% can be achieved following this approach, which could be relevant for practical applications.

  3. Molecular characterization of Banana streak virus isolate from Musa Acuminata in China.

    Science.gov (United States)

    Zhuang, Jun; Wang, Jian-Hua; Zhang, Xin; Liu, Zhi-Xin

    2011-12-01

    Banana streak virus (BSV), a member of genus Badnavirus, is a causal agent of banana streak disease throughout the world. The genetic diversity of BSVs from different regions of banana plantations has previously been investigated, but there are relatively few reports of the genetic characteristic of episomal (non-integrated) BSV genomes isolated from China. Here, the complete genome, a total of 7722bp (GenBank accession number DQ092436), of an isolate of Banana streak virus (BSV) on cultivar Cavendish (BSAcYNV) in Yunnan, China was determined. The genome organises in the typical manner of badnaviruses. The intergenic region of genomic DNA contains a large stem-loop, which may contribute to the ribosome shift into the following open reading frames (ORFs). The coding region of BSAcYNV consists of three overlapping ORFs, ORF1 with a non-AUG start codon and ORF2 encoding two small proteins are individually involved in viral movement and ORF3 encodes a polyprotein. Besides the complete genome, a defective genome lacking the whole RNA leader region and a majority of ORF1 and which encompasses 6525bp was also isolated and sequenced from this BSV DNA reservoir in infected banana plants. Sequence analyses showed that BSAcYNV has closest similarity in terms of genome organization and the coding assignments with an BSV isolate from Vietnam (BSAcVNV). The corresponding coding regions shared identities of 88% and -95% at nucleotide and amino acid levels, respectively. Phylogenetic analysis also indicated BSAcYNV shared the closest geographical evolutionary relationship to BSAcVNV among sequenced banana streak badnaviruses.

  4. Relationship Analysis Between Leaf-Stomata Characteristics with Cocoa Resistance to Vascular-Streak Dieback

    OpenAIRE

    Wahyu Soesilo, Agung; Arisandy, Poppy; Sari, Indah Anita; Harimurti, Rudi

    2016-01-01

    Characteristics of leaf-stomata indicate having relationship with the resistance of cocoa to vascular-streak dieback (VSD) caused by Ceratobasidum theobromae. This research has objective to identify the relationship between leaf-stomata haracteristicsto VSD resistance in order to develop criteria for selection. Trial was establised in randomized-complete block design with three blocks as replications in Kaliwining Experimental Station of Indonesian Coffee and Cocoa R...

  5. Full Annulus Numerical Study of Hot Streaks Propagation in a Hydrogen-rich Syngas-Fired Heavy Duty Axial Turbine

    OpenAIRE

    Ioannou, E.; Sayma, A. I.

    2017-01-01

    This paper presents a study of the effect of fuel composition on hot streaks propagation in a high-pressure turbine using a full annulus unsteady computational fluid dynamics analysis of the first two stages. Hot streaks result from the inherent non-uniformities of temperature profiles at the exit of the combustion chamber. Variations in composition arise from current challenges requiring gas turbines to adapt to fuel variations driven by the need to reduce CO2 emissions through the use of sy...

  6. Signal-to-noise performance analysis of streak tube imaging lidar systems. I. Cascaded model.

    Science.gov (United States)

    Yang, Hongru; Wu, Lei; Wang, Xiaopeng; Chen, Chao; Yu, Bing; Yang, Bin; Yuan, Liang; Wu, Lipeng; Xue, Zhanli; Li, Gaoping; Wu, Baoning

    2012-12-20

    Streak tube imaging lidar (STIL) is an active imaging system using a pulsed laser transmitter and a streak tube receiver to produce 3D range and intensity imagery. The STIL has recently attracted a great deal of interest and attention due to its advantages of wide azimuth field-of-view, high range and angle resolution, and high frame rate. This work investigates the signal-to-noise performance of STIL systems. A theoretical model for characterizing the signal-to-noise performance of the STIL system with an internal or external intensified streak tube receiver is presented, based on the linear cascaded systems theory of signal and noise propagation. The STIL system is decomposed into a series of cascaded imaging chains whose signal and noise transfer properties are described by the general (or the spatial-frequency dependent) noise factors (NFs). Expressions for the general NFs of the cascaded chains (or the main components) in the STIL system are derived. The work presented here is useful for the design and evaluation of STIL systems.

  7. Genetic Analysis of Streaked and Abnormal Floret Mutant st-fon

    Directory of Open Access Journals (Sweden)

    De-xi CHEN

    2013-07-01

    Full Text Available A double mutant with streaked leaf and abnormal floret was found and temporarily named streaked leaf and floral organ number mutant (st-fon. For this mutant, besides white streak appeared on culm, leaves and panicles, the number of floral organs increased and florets cracked. The extreme phenotype was that several small florets grew from one floret or branch rachis in small florets extended and developed into panicles. By using transmission electron microscope to observe the ultrastructure of white histocytes of leaves at the seedling stage, the white tissues which showed abnormal plastids, lamellas and thylakoids could not develop into normal chloroplast, and the development of chloroplast was blocked at the early growth stage of plastid. Scanning electron microscope and paraffin section were also used to observe the development of floral organs, and the results indicated that the development of floral meristem was out of order and unlimited, whereas in the twisty leaves, vascular bundle sheath cells grew excessively, or some bubbly cells increased. Genetic analyses carried out by means of cross and backcross with four normal-leaf-color materials revealed that the mutant is of cytoplasm inheritance.

  8. Development of a Data Reduction Algorithm for Optical Wide Field Patrol (OWL II: Improving Measurement of Lengths of Detected Streaks

    Directory of Open Access Journals (Sweden)

    Sun-Youp Park

    2016-09-01

    Full Text Available As described in the previous paper (Park et al. 2013, the detector subsystem of optical wide-field patrol (OWL provides many observational data points of a single artificial satellite or space debris in the form of small streaks, using a chopper system and a time tagger. The position and the corresponding time data are matched assuming that the length of a streak on the CCD frame is proportional to the time duration of the exposure during which the chopper blades do not obscure the CCD window. In the previous study, however, the length was measured using the diagonal of the rectangle of the image area containing the streak; the results were quite ambiguous and inaccurate, allowing possible matching error of positions and time data. Furthermore, because only one (position, time data point is created from one streak, the efficiency of the observation decreases. To define the length of a streak correctly, it is important to locate the endpoints of a streak. In this paper, a method using a differential convolution mask pattern is tested. This method can be used to obtain the positions where the pixel values are changed sharply. These endpoints can be regarded as directly detected positional data, and the number of data points is doubled by this result.

  9. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  10. Junocam: Juno's Outreach Camera

    Science.gov (United States)

    Hansen, C. J.; Caplinger, M. A.; Ingersoll, A.; Ravine, M. A.; Jensen, E.; Bolton, S.; Orton, G.

    2017-11-01

    Junocam is a wide-angle camera designed to capture the unique polar perspective of Jupiter offered by Juno's polar orbit. Junocam's four-color images include the best spatial resolution ever acquired of Jupiter's cloudtops. Junocam will look for convective clouds and lightning in thunderstorms and derive the heights of the clouds. Junocam will support Juno's radiometer experiment by identifying any unusual atmospheric conditions such as hotspots. Junocam is on the spacecraft explicitly to reach out to the public and share the excitement of space exploration. The public is an essential part of our virtual team: amateur astronomers will supply ground-based images for use in planning, the public will weigh in on which images to acquire, and the amateur image processing community will help process the data.

  11. CCD camera for an autoguider

    Science.gov (United States)

    Schempp, William V.

    1991-06-01

    The requirements of a charge coupled device (CCD) autoguider camera and the specifications of a camera that we propose to build to meet those requirements will be discussed. The design goals of both the package and the electronics will be considered.

  12. Digital camera self-calibration

    Science.gov (United States)

    Fraser, Clive S.

    Over the 25 years since the introduction of analytical camera self-calibration there has been a revolution in close-range photogrammetric image acquisition systems. High-resolution, large-area 'digital' CCD sensors have all but replaced film cameras. Throughout the period of this transition, self-calibration models have remained essentially unchanged. This paper reviews the application of analytical self-calibration to digital cameras. Computer vision perspectives are touched upon, the quality of self-calibration is discussed, and an overview is given of each of the four main sources of departures from collinearity in CCD cameras. Practical issues are also addressed and experimental results are used to highlight important characteristics of digital camera self-calibration.

  13. Attosecond Electron Correlation Dynamics in Double Ionization of Benzene Probed with Two-Electron Angular Streaking

    Science.gov (United States)

    Winney, Alexander H.; Lee, Suk Kyoung; Lin, Yun Fei; Liao, Qing; Adhikari, Pradip; Basnayake, Gihan; Schlegel, H. Bernhard; Li, Wen

    2017-09-01

    With a novel three-dimensional electron-electron coincidence imaging technique and two-electron angular streaking method, we show that the emission time delay between two electrons can be measured from tens of attoseconds to more than 1 fs. Surprisingly, in benzene, the double ionization rate decays as the time delay between the first and second electron emission increases during the first 500 as. This is further supported by the decay of the Coulomb repulsion in the direction perpendicular to the laser polarization. This result reveals that laser-induced electron correlation plays a major role in strong field double ionization of benzene driven by a nearly circularly polarized field.

  14. Loop-mediated Isothermal Amplification Assay to Rapidly Detect Wheat Streak Mosaic Virus in Quarantined Plants

    Directory of Open Access Journals (Sweden)

    Siwon Lee

    2015-12-01

    Full Text Available We developed a loop-mediated isothermal amplification (LAMP method to rapidly diagnose Wheat streak mosaic virus (WSMV during quarantine inspections of imported wheat, corn, oats, and millet. The LAMP method was developed as a plant quarantine inspection method for the first time, and its simplicity, quickness, specificity and sensitivity were verified compared to current reverse transcription-polymerase chain reaction (RT-PCR and nested PCR quarantine methods. We were able to quickly screen for WSMV at quarantine sites with many test samples; thus, this method is expected to contribute to plant quarantine inspections.

  15. Insufficient buffer capacity in up chamber leads to vertical streaking of two-dimensional electrophoresis

    OpenAIRE

    Ke-hua JIN

    2011-01-01

    Objective To study the effect of buffer capacity in up chamber on vertical streaking(VSTK) of two-dimensional electrophoresis.Methods The same buffer volume was kept in up chamber,VSTK was compared by running two SDS gels or single one in 1× Laemmli buffer(buffer),or two ones in 1.5×,2× and 3× buffer in up chamber respectively.Results VSTK appeared severely when two gels were run in 1× buffer,while disappeared when one did.When two gels were run in 1.5×buffer,VSTK only existed in the region o...

  16. Robotic Arm Camera on Mars with Lights On

    Science.gov (United States)

    2008-01-01

    This image is a composite view of NASA's Phoenix Mars Lander's Robotic Arm Camera (RAC) with its lights on, as seen by the lander's Surface Stereo Imager (SSI). This image combines images taken on the afternoon of Phoenix's 116th Martian day, or sol (September 22, 2008). The RAC is about 8 centimeters (3 inches) tall. The SSI took images of the RAC to test both the light-emitting diodes (LEDs) and cover function. Individual images were taken in three SSI filters that correspond to the red, green, and blue LEDs one at a time. When combined, it appears that all three sets of LEDs are on at the same time. This composite image is not true color. The streaks of color extending from the LEDs are an artifact from saturated exposure. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  17. New generation of meteorology cameras

    Science.gov (United States)

    Janout, Petr; Blažek, Martin; Páta, Petr

    2017-12-01

    A new generation of the WILLIAM (WIde-field aLL-sky Image Analyzing Monitoring system) camera includes new features such as monitoring of rain and storm clouds during the day observation. Development of the new generation of weather monitoring cameras responds to the demand for monitoring of sudden weather changes. However, new WILLIAM cameras are ready to process acquired image data immediately, release warning against sudden torrential rains, and send it to user's cell phone and email. Actual weather conditions are determined from image data, and results of image processing are complemented by data from sensors of temperature, humidity, and atmospheric pressure. In this paper, we present the architecture, image data processing algorithms of mentioned monitoring camera and spatially-variant model of imaging system aberrations based on Zernike polynomials.

  18. An Inexpensive Digital Infrared Camera

    Science.gov (United States)

    Mills, Allan

    2012-01-01

    Details are given for the conversion of an inexpensive webcam to a camera specifically sensitive to the near infrared (700-1000 nm). Some experiments and practical applications are suggested and illustrated. (Contains 9 figures.)

  19. Scanning laser video camera/ microscope

    Science.gov (United States)

    Wang, C. P.; Bow, R. T.

    1984-10-01

    A laser scanning system capable of scanning at standard video rate has been developed. The scanning mirrors, circuit design and system performance, as well as its applications to video cameras and ultra-violet microscopes, are discussed.

  20. Automatic Reacquisition of Satellite Positions by Detecting Their Expected Streaks in Astronomical Images

    Science.gov (United States)

    Levesque, M.

    Artificial satellites, and particularly space junk, drift continuously from their known orbits. In the surveillance-of-space context, they must be observed frequently to ensure that the corresponding orbital parameter database entries are up-to-date. Autonomous ground-based optical systems are periodically tasked to observe these objects, calculate the difference between their predicted and real positions and update object orbital parameters. The real satellite positions are provided by the detection of the satellite streaks in the astronomical images specifically acquired for this purpose. This paper presents the image processing techniques used to detect and extract the satellite positions. The methodology includes several processing steps including: image background estimation and removal, star detection and removal, an iterative matched filter for streak detection, and finally false alarm rejection algorithms. This detection methodology is able to detect very faint objects. Simulated data were used to evaluate the methodology's performance and determine the sensitivity limits where the algorithm can perform detection without false alarm, which is essential to avoid corruption of the orbital parameter database.

  1. Epistatic determinism of durum wheat resistance to the wheat spindle streak mosaic virus.

    Science.gov (United States)

    Holtz, Yan; Bonnefoy, Michel; Viader, Véronique; Ardisson, Morgane; Rode, Nicolas O; Poux, Gérard; Roumet, Pierre; Marie-Jeanne, Véronique; Ranwez, Vincent; Santoni, Sylvain; Gouache, David; David, Jacques L

    2017-07-01

    The resistance of durum wheat to the Wheat spindle streak mosaic virus (WSSMV) is controlled by two main QTLs on chromosomes 7A and 7B, with a huge epistatic effect. Wheat spindle streak mosaic virus (WSSMV) is a major disease of durum wheat in Europe and North America. Breeding WSSMV-resistant cultivars is currently the only way to control the virus since no treatment is available. This paper reports studies of the inheritance of WSSMV resistance using two related durum wheat populations obtained by crossing two elite cultivars with a WSSMV-resistant emmer cultivar. In 2012 and 2015, 354 recombinant inbred lines (RIL) were phenotyped using visual notations, ELISA and qPCR and genotyped using locus targeted capture and sequencing. This allowed us to build a consensus genetic map of 8568 markers and identify three chromosomal regions involved in WSSMV resistance. Two major regions (located on chromosomes 7A and 7B) jointly explain, on the basis of epistatic interactions, up to 43% of the phenotypic variation. Flanking sequences of our genetic markers are provided to facilitate future marker-assisted selection of WSSMV-resistant cultivars.

  2. The effect of Aloe vera leaf gel on fatty streak formation in hypercholesterolemic rabbits.

    Science.gov (United States)

    Dana, Nasim; Javanmard, Shaghayegh Haghjooy; Asgary, Sedigheh; Asnaashari, Hossein; Abdian, Narges

    2012-05-01

    Atherosclerosis is a complex disease that is associated with a variety of etiologic factors such as hyperlipidemia and inflammation. Aloe vera (Liliaceae family) has been used traditionally as an anti-inflammatory drug. The aims of this survey were to define the beneficial effects of Aloe vera leaf gel on some of the atherosclerosis risk factors, and also fatty streak formation in hypercholesterolemic rabbits. [corrected] 32 white male rabbits were randomly divided into four experimental groups (n = 8, each). During the study, the animals had a standard diet (control group), high cholesterol diet (HC group), high cholesterol diet with Aloe vera leaf gel (3.2%v/v) (HC+ Aloe group) and Aloe vera leaf gel (Aloe group) for 30 days. Fasting blood samples were collected from all animals at the beginning and end of the study. Then total cholesterol (TC), fasting blood sugar (FBS), triglyceride (TG) and CRP were measured before and after experimental periods. By the end of the study, the aortas were removed and investigated for atherosclerosis plaque formation. Significant differences were observed in TC and CRP levels of the high-cholesterol diet with Aloe vera and the high-cholesterol diet alone (p Aloe vera(p Aloe vera has beneficial effects on the prevention of fatty streak development; it may reduce the development of atherosclerosis through modification of risk factors. However, further studies are needed to understand the mechanisms whereby this plant exerts its anti-atherosclerotic effects.

  3. Crowd Motion Analysis Based on Social Force Graph with Streak Flow Attribute

    Directory of Open Access Journals (Sweden)

    Shaonian Huang

    2015-01-01

    Full Text Available Over the past decades, crowd management has attracted a great deal of attention in the area of video surveillance. Among various tasks of video surveillance analysis, crowd motion analysis is the basis of numerous subsequent applications of surveillance video. In this paper, a novel social force graph with streak flow attribute is proposed to capture the global spatiotemporal changes and the local motion of crowd video. Crowd motion analysis is hereby implemented based on the characteristics of social force graph. First, the streak flow of crowd sequence is extracted to represent the global crowd motion; after that, spatiotemporal analogous patches are obtained based on the crowd visual features. A weighted social force graph is then constructed based on multiple social properties of crowd video. The graph is segmented into particle groups to represent the similar motion patterns of crowd video. A codebook is then constructed by clustering all local particle groups, and consequently crowd abnormal behaviors are detected by using the Latent Dirichlet Allocation model. Extensive experiments on challenging datasets show that the proposed method achieves preferable results in the application of crowd motion segmentation and abnormal behavior detection.

  4. Small Near-Earth Asteroids in the Palomar Transient Factory Survey: A Real-Time Streak-detection System

    Science.gov (United States)

    Waszczak, Adam; Prince, Thomas A.; Laher, Russ; Masci, Frank; Bue, Brian; Rebbapragada, Umaa; Barlow, Tom; Surace, Jason; Helou, George; Kulkarni, Shrinivas

    2017-03-01

    Near-Earth asteroids (NEAs) in the 1-100 meter size range are estimated to be ˜1,000 times more numerous than the ˜15,000 currently cataloged NEAs, most of which are in the 0.5-10 kilometer size range. Impacts from 10-100 meter size NEAs are not statistically life-threatening, but may cause significant regional damage, while 1-10 meter size NEAs with low velocities relative to Earth are compelling targets for space missions. We describe the implementation and initial results of a real-time NEA-discovery system specialized for the detection of small, high angular rate (visually streaked) NEAs in Palomar Transient Factory (PTF) images. PTF is a 1.2-m aperture, 7.3 deg2 field of view (FOV) optical survey designed primarily for the discovery of extragalactic transients (e.g., supernovae) in 60-second exposures reaching ˜20.5 visual magnitude. Our real-time NEA discovery pipeline uses a machine-learned classifier to filter a large number of false-positive streak detections, permitting a human scanner to efficiently and remotely identify real asteroid streaks during the night. Upon recognition of a streaked NEA detection (typically within an hour of the discovery exposure), the scanner triggers follow-up with the same telescope and posts the observations to the Minor Planet Center for worldwide confirmation. We describe our 11 initial confirmed discoveries, all small NEAs that passed 0.3-15 lunar distances from Earth. Lastly, we derive useful scaling laws for comparing streaked-NEA-detection capabilities of different surveys as a function of their hardware and survey-pattern characteristics. This work most directly informs estimates of the streak-detection capabilities of the Zwicky Transient Facility (ZTF, planned to succeed PTF in 2017), which will apply PTF’s current resolution and sensitivity over a 47-deg2 FOV.

  5. Inactivation of the Huntington's disease gene (Hdh impairs anterior streak formation and early patterning of the mouse embryo

    Directory of Open Access Journals (Sweden)

    Conlon Ronald A

    2005-08-01

    Full Text Available Abstract Background Huntingtin, the HD gene encoded protein mutated by polyglutamine expansion in Huntington's disease, is required in extraembryonic tissues for proper gastrulation, implicating its activities in nutrition or patterning of the developing embryo. To test these possibilities, we have used whole mount in situ hybridization to examine embryonic patterning and morphogenesis in homozygous Hdhex4/5 huntingtin deficient embryos. Results In the absence of huntingtin, expression of nutritive genes appears normal but E7.0–7.5 embryos exhibit a unique combination of patterning defects. Notable are a shortened primitive streak, absence of a proper node and diminished production of anterior streak derivatives. Reduced Wnt3a, Tbx6 and Dll1 expression signify decreased paraxial mesoderm and reduced Otx2 expression and lack of headfolds denote a failure of head development. In addition, genes initially broadly expressed are not properly restricted to the posterior, as evidenced by the ectopic expression of Nodal, Fgf8 and Gsc in the epiblast and T (Brachyury and Evx1 in proximal mesoderm derivatives. Despite impaired posterior restriction and anterior streak deficits, overall anterior/posterior polarity is established. A single primitive streak forms and marker expression shows that the anterior epiblast and anterior visceral endoderm (AVE are specified. Conclusion Huntingtin is essential in the early patterning of the embryo for formation of the anterior region of the primitive streak, and for down-regulation of a subset of dynamic growth and transcription factor genes. These findings provide fundamental starting points for identifying the novel cellular and molecular activities of huntingtin in the extraembryonic tissues that govern normal anterior streak development. This knowledge may prove to be important for understanding the mechanism by which the dominant polyglutamine expansion in huntingtin determines the loss of neurons in

  6. 'Put Your Money Where Your Mouth Is!': Effects of Streaks on Confidence and Betting in a Binary Choice Task.

    Science.gov (United States)

    Studer, Bettina; Limbrick-Oldfield, Eve H; Clark, Luke

    2015-07-01

    Human choice under uncertainty is influenced by erroneous beliefs about randomness. In simple binary choice tasks, such as red/black predictions in roulette, long outcome runs (e.g. red, red, red) typically increase the tendency to predict the other outcome (i.e. black), an effect labeled the "gambler's fallacy." In these settings, participants may also attend to streaks in their predictive performance. Winning and losing streaks are thought to affect decision confidence, although prior work indicates conflicting directions. Over three laboratory experiments involving red/black predictions in a sequential roulette task, we sought to identify the effects of outcome runs and winning/losing streaks upon color predictions, decision confidence and betting behavior. Experiments 1 (n = 40) and 3 (n = 40) obtained trial-by-trial confidence ratings, with a win/no win payoff and a no loss/loss payoff, respectively. Experiment 2 (n = 39) obtained a trial-by-trial bet amount on an equivalent scale. In each experiment, the gambler's fallacy was observed on choice behavior after color runs and, in experiment 2, on betting behavior after color runs. Feedback streaks exerted no reliable influence on confidence ratings, in either payoff condition. Betting behavior, on the other hand, increased as a function of losing streaks. The increase in betting on losing streaks is interpreted as a manifestation of loss chasing; these data help clarify the psychological mechanisms underlying loss chasing and caution against the use of betting measures ("post-decision wagering") as a straightforward index of decision confidence. © 2014 The Authors. Journal of Behavioral Decision Making published by John Wiley & Sons Ltd.

  7. Radiation Spectral Analysis and Particle Temperature/Velocity Measurement in Plasma Spray with One-Color Camera

    Science.gov (United States)

    Wang, B. H.; Li, B. Q.; Yang, Huan; Bai, Y.

    2017-10-01

    A color camera optical diagnostic imaging system has been developed for the measurement of temperature and velocity of individual in-flight particles in thermal plasma spray, based on the principle of particle streak velocimetry and two-color thermometry. Radiation spectral analysis of the characteristic behavior of a particle-laden plasma plume was performed to identify an optimal spectral range for accurate temperature measurements over which the powder particles and the interfering thermal plasma gas are discernable. Calibration of the thermal imaging system was carried out using a blackbody furnace with uncertainties less than 1.8%. Extensive experimental measurements were taken with the optical imaging system to obtain the temperature and velocity distributions of YSZ particles in practical plasma spraying applications. The uncertainties of the measured temperature and velocity with a color camera system mostly fluctuate around ±10% in comparison with data obtained from a commercially available measuring system.

  8. INT prime focus mosaic camera

    Science.gov (United States)

    Ives, Derek J.; Tulloch, Simon; Churchill, John

    1996-03-01

    The INT Prime Focus Mosaic Camera (INT PFC) is designed to provide a large field survey and supernovae search capability for the prime focus of the 2.5 m Isaac Newton Telescope (INT). It is a joint collaboration between the Royal Greenwich Observatory (UK), Kapteyn Sterrenwacht Werkgroep (Netherlands), and the Lawrence Berkeley Laboratories (USA). The INT PFC consists of a 4 chip mosaic utilizing thinned and anti-reflection coated CCDs. These are LORAL devices of the LICK3 design. They will be operated cryogenically in a purpose built camera assembly. A fifth CCD, of the same type, is co-mounted with the science array in the cryostat to provide autoguider functions. This cryostat then mounts to the main camera assembly at the prime focus. This assembly will include standard filters and a novel shutter wheel which has been specifically designed for this application. The camera will have an unvignetted field of 40 arcminutes and a focal ratio of f/3.3. This results in a very tight mechanical specification for co-planarity and flatness of the array of CCDs and also quite stringent flexure tolerance of the camera assembly. A method of characterizing the co- planarity and flatness of the array will be described. The overall system architecture will also be described. One of the main requirements is to read the whole array out within 100s, with less than 10e rms. noise and very low CCD cross talk.

  9. The Clementine longwave infrared camera

    Energy Technology Data Exchange (ETDEWEB)

    Priest, R.E.; Lewis, I.T.; Sewall, N.R.; Park, H.S.; Shannon, M.J.; Ledebuhr, A.G.; Pleasance, L.D. [Lawrence Livermore National Lab., CA (United States); Massie, M.A. [Pacific Advanced Technology, Solvang, CA (United States); Metschuleit, K. [Amber/A Raytheon Co., Goleta, CA (United States)

    1995-04-01

    The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth and space were returned from this mission. The longwave-infrared (LWIR) camera supplemented the UV/Visible and near-infrared mapping cameras providing limited strip coverage of the moon, giving insight to the thermal properties of the soils. This camera provided {approximately}100 m spatial resolution at 400 km periselene, and a 7 km across-track swath. This 2.1 kg camera using a 128 x 128 Mercury-Cadmium-Telluride (MCT) FPA viewed thermal emission of the lunar surface and lunar horizon in the 8.0 to 9.5 {micro}m wavelength region. A description of this light-weight, low power LWIR camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission`s primary objective for flight qualifying the sensors for future Department of Defense flights.

  10. Camera Movement in Narrative Cinema

    DEFF Research Database (Denmark)

    Nielsen, Jakob Isak

    2007-01-01

    Just like art historians have focused on e.g. composition or lighting, this dissertation takes a single stylistic parameter as its object of study: camera movement. Within film studies this localized avenue of middle-level research has become increasingly viable under the aegis of a perspective......, and that a given camera movement may activate one or more of the proposed functions at any given moment. Six main functions are proposed and defined: 1) Orientation: orienting the viewer spatially. 2) Pacing: contributing to the cinematic rhythm of the film. 3) Inflection: inflecting shots in a suggestive...... to illustrate how the functions may mesh in individual camera movements six concrete examples are analyzed. The analyses illustrate how the taxonomy presented can substantiate analysis and interpretation of film style. More generally, the dissertation - and particularly these in-depth analyses - illustrates how...

  11. Perceptual Color Characterization of Cameras

    Directory of Open Access Journals (Sweden)

    Javier Vazquez-Corral

    2014-12-01

    Full Text Available Color camera characterization, mapping outputs from the camera sensors to an independent color space, such as \\(XYZ\\, is an important step in the camera processing pipeline. Until now, this procedure has been primarily solved by using a \\(3 \\times 3\\ matrix obtained via a least-squares optimization. In this paper, we propose to use the spherical sampling method, recently published by Finlayson al., to perform a perceptual color characterization. In particular, we search for the \\(3 \\times 3\\ matrix that minimizes three different perceptual errors, one pixel based and two spatially based. For the pixel-based case, we minimize the CIE \\(\\Delta E\\ error, while for the spatial-based case, we minimize both the S-CIELAB error and the CID error measure. Our results demonstrate an improvement of approximately 3for the \\(\\Delta E\\ error, 7& for the S-CIELAB error and 13% for the CID error measures.

  12. Dark Energy Camera for Blanco

    Energy Technology Data Exchange (ETDEWEB)

    Binder, Gary A.; /Caltech /SLAC

    2010-08-25

    In order to make accurate measurements of dark energy, a system is needed to monitor the focus and alignment of the Dark Energy Camera (DECam) to be located on the Blanco 4m Telescope for the upcoming Dark Energy Survey. One new approach under development is to fit out-of-focus star images to a point spread function from which information about the focus and tilt of the camera can be obtained. As a first test of a new algorithm using this idea, simulated star images produced from a model of DECam in the optics software Zemax were fitted. Then, real images from the Mosaic II imager currently installed on the Blanco telescope were used to investigate the algorithm's capabilities. A number of problems with the algorithm were found, and more work is needed to understand its limitations and improve its capabilities so it can reliably predict camera alignment and focus.

  13. Radiation-Tolerant High-Speed Camera

    Science.gov (United States)

    2017-03-01

    Radiation -Tolerant High-Speed Camera Esko Mikkola, Andrew Levy, Matt Engelman Alphacore, Inc. Tempe, AZ 85281 Abstract: As part of an... radiation -hardened CMOS image sensor and camera system. Radiation -hardened cameras with frame rates as high as 10 kfps and resolution of 1Mpixel are not...camera solution that is under development with a similar architecture. It also includes a brief description of the radiation -hardened camera that

  14. Long-term follow-up of choroidal neovascularization secondary to angioid streaks: case series and literature review

    Directory of Open Access Journals (Sweden)

    Al-Rashaed S

    2012-07-01

    Full Text Available Saba Al-Rashaed, J Fernando ArevaloKing Khaled Eye Specialist Hospital, Riyadh, Saudi ArabiaBackground: The purpose of this paper is to report the clinical course of choroidal neovascularization (CNV secondary to angioid streaks and the outcomes in response to different treatment modalities.Methods: This was a case series of two consecutive patients (four eyes with CNV secondary to angioid streaks. Visual acuity, ophthalmological examination, color photographs, fluorescein angiography, and optical coherence tomography were used to assess the outcomes of treatment.Results: Two eyes were treated with photodynamic therapy for subfoveal choroidal neovascular membrane, one eye underwent thermal laser photocoagulation for extrafoveal CNV followed by intravitreal bevacizumab for subfoveal CNV, and one eye underwent intravitreal bevacizumab for subfoveal CNV. The follow-up period was 4–6 years. The final visual acuities of all eyes were 20/300 or worse with large submacular fibrosis.Conclusion: CNV secondary to angioid streaks in these two patients had a poor prognosis despite undergoing different types of treatment. Poor outcome was likely related to frequent recurrence and newly developed CNV, which remained a clinical concern in these cases.Keywords: choroidal neovascular membrane, angioid streaks, intravitreal bevacizumab, photodynamic therapy

  15. Evaluation of triticale accessions for resistance to wheat bacterial leaf streak caused by Xanthomonas translucens pv. undulosa

    Science.gov (United States)

    The bacterium Xanthomonas translucens pv. undulosa (Xtu) causes bacterial leaf streak (BLS) on wheat and other small grains. Several triticale accessions were reported to possess high levels of resistance to wheat Xtu strains. In this study, we evaluated a worldwide collection of 502 triticale acces...

  16. Compositions of Low Albedo Intracrater Materials and Wind Streaks on Mars: Examination of MGS TES Data in Western Arabia Terra

    Science.gov (United States)

    Bandfield, J. L.; Wyatt, M. B.; Christensen, P.; McSween, H. Y., Jr.

    2001-01-01

    Basalt and andesite surface compositions are identified within individual low albedo intracrater features and adjacent dark wind streaks. High resolution mapping of compositional heterogeneities may help constrain origin hypotheses for these features. Additional information is contained in the original extended abstract.

  17. Introgression of chromosome segments from multiple alien species in wheat breeding lines with wheat streak mosaic virus resistance

    Science.gov (United States)

    Pyramiding of alien-derived Wheat streak mosaic virus (WSMV) resistance and resistance enhancing genes in wheat is a costeffective and environmentally safe strategy for disease control. PCR-based markers and cytogenetic analysis with genomic in situ hybridisation were applied to identify alien chrom...

  18. The genome organization of lucerne transient streak and turnip rosette sobemoviruses revisited.

    Science.gov (United States)

    Sõmera, Merike; Truve, Erkki

    2013-03-01

    Unlike other sobemoviruses, lucerne transient streak virus (LTSV) and turnip rosette virus (TRoV) have been reported to contain two successive ORF1s (denoted as ORF1a and ORF1b) instead of a single ORF1. Also, their next ORF (ORF2a/2a2b) has been mapped to a region ca. 200 nucleotides downstream from that of other sobemoviruses, leading to the lack of transmembrane segments at the N-termini of P2a/2a2b. In the current study, we resequenced this region for TRoV and LTSV. The hypothetical beginning of ORF1b was mapped as the beginning of ORF2a/2a2b for both TRoV and LTSV. Computional analysis revealed transmembrane segments at the N-termini of the TRoV and LTSV polyproteins.

  19. Shiny white streaks: a sign of malignancy at dermoscopy of pigmented skin lesions.

    Science.gov (United States)

    Shitara, Danielle; Ishioka, Priscila; Alonso-Pinedo, Yarel; Palacios-Bejarano, Leyla; Carrera, Cristina; Malvehy, Josep; Puig, Susana

    2014-03-01

    The aim of this study was to evaluate the practical importance of the presence of shiny white streaks (SWS) (chrysalis or crystalline structures in polarized dermoscopy) for suspicion of malignancy, diagnosis of melanoma, and pre-operative estimation of Breslow thickness and its correlation with total dermoscopy score (TDS). SWS were present in 13.6% of 800 consecutive excised lesions. The presence of SWS was associated with malignancy (odds ratio (OR) 10.534, 95% confidence interval (95% CI) 6.357-17.455, p lesions with invasive melanoma (OR 10.333, 95% CI 3.812-28.014) and melanomas with high TDS (OR 6.286, 95% CI 1.673-23.619), but was also a factor in the diagnosis of featureless and some thin melanomas. These results corroborate the clinical applicability of SWS in aiding the diagnosis of malignancy and helping to raise the general dermatologist's awareness in cases of doubt and featureless lesions.

  20. Time-resolved measurements with streaked diffraction patterns from electrons generated in laser plasma wakefield

    Science.gov (United States)

    He, Zhaohan; Nees, John; Hou, Bixue; Krushelnick, Karl; Thomas, Alec; Beaurepaire, Benoît; Malka, Victor; Faure, Jérôme

    2013-10-01

    Femtosecond bunches of electrons with relativistic to ultra-relativistic energies can be robustly produced in laser plasma wakefield accelerators (LWFA). Scaling the electron energy down to sub-relativistic and MeV level using a millijoule laser system will make such electron source a promising candidate for ultrafast electron diffraction (UED) applications due to the intrinsic short bunch duration and perfect synchronization with the optical pump. Recent results of electron diffraction from a single crystal gold foil, using LWFA electrons driven by 8-mJ, 35-fs laser pulses at 500 Hz, will be presented. The accelerated electrons were collimated with a solenoid magnetic lens. By applying a small-angle tilt to the magnetic lens, the diffraction pattern can be streaked such that the temporal evolution is separated spatially on the detector screen after propagation. The observable time window and achievable temporal resolution are studied in pump-probe measurements of photo-induced heating on the gold foil.

  1. Streaking temporal double slit interference by an orthogonal two-color laser field

    CERN Document Server

    Richter, Martin; Schöffler, Markus; Jahnke, Till; Schmidt, Lothar P H; Li, Min; Liu, Yunquan; Dörner, Reinhard

    2015-01-01

    We investigate electron momentum distributions from single ionization of Ar by two orthogonally polarized laser pulses of different color. The two-color scheme is used to experimentally control the interference between electron wave packets released at different times within one laser cycle. This intracycle interference pattern is typically hard to resolve in an experiment. With the two-color control scheme these features become the dominant contribution to the electron momentum distribution. Furthermore the second color can be used for streaking of the otherwise interfering wave packets establishing a which-way marker. Our investigation shows that the visibility of the interference fringes depends on the degree of the which-way information determined by the controllable phase between the two pulses.

  2. The complete nucleotide sequence and genome organization of pea streak virus (genus Carlavirus).

    Science.gov (United States)

    Su, Li; Li, Zhengnan; Bernardy, Mike; Wiersma, Paul A; Cheng, Zhihui; Xiang, Yu

    2015-10-01

    Pea streak virus (PeSV) is a member of the genus Carlavirus in the family Betaflexiviridae. Here, the first complete genome sequence of PeSV was determined by deep sequencing of a cDNA library constructed from dsRNA extracted from a PeSV-infected sample and Rapid Amplification of cDNA Ends (RACE) PCR. The PeSV genome consists of 8041 nucleotides excluding the poly(A) tail and contains six open reading frames (ORFs). The putative peptide encoded by the PeSV ORF6 has an estimated molecular mass of 6.6 kDa and shows no similarity to any known proteins. This differs from typical carlaviruses, whose ORF6 encodes a 12- to 18-kDa cysteine-rich nucleic-acid-binding protein.

  3. Stimulant Paste Preparation and Bark Streak Tapping Technique for Pine Oleoresin Extraction.

    Science.gov (United States)

    Füller, Thanise Nogueira; de Lima, Júlio César; de Costa, Fernanda; Rodrigues-Corrêa, Kelly C S; Fett-Neto, Arthur G

    2016-01-01

    Tapping technique comprises the extraction of pine oleoresin, a non-wood forest product consisting of a complex mixture of mono, sesqui, and diterpenes biosynthesized and exuded as a defense response to wounding. Oleoresin is used to produce gum rosin, turpentine, and their multiple derivatives. Oleoresin yield and quality are objects of interest in pine tree biotechnology, both in terms of environmental and genetic control. Monitoring these parameters in individual trees grown in the field provides a means to examine the control of terpene production in resin canals, as well as the identification of genetic-based differences in resinosis. A typical method of tapping involves the removal of bark and application of a chemical stimulant on the wounded area. Here we describe the methods for preparing the resin-stimulant paste with different adjuvants, as well as the bark streaking process in adult pine trees.

  4. Tracing dynamics of laser-induced fields on ultrathin foils using complementary imaging with streak deflectometry

    Science.gov (United States)

    Abicht, F.; Braenzel, J.; Priebe, G.; Koschitzki, Ch.; Andreev, A. A.; Nickles, P. V.; Sander, W.; Schnürer, M.

    2016-09-01

    We present a detailed study of the electric and magnetic fields, which are created on plasma vacuum interfaces as a result of highly intense laser-matter interactions. For the field generation ultrathin polymer foils (30-50 nm) were irradiated with high intensity femtosecond (1019 - 1020 W /cm2 ) and picosecond (˜1017 W /cm2 ) laser pulses with ultrahigh contrast (1010 - 1011 ). To determine the temporal evolution and the spatial distribution of these fields the proton streak deflectometry method has been developed further and applied in two different imaging configurations. It enabled us to gather complementary information about the investigated field structure, in particular about the influence of different field components (parallel and normal to the target surface) and the impact of a moving ion front. The applied ultrahigh laser contrast significantly increased the reproducibility of the experiment and improved the accuracy of the imaging method. In order to explain the experimental observations, which were obtained by applying ultrashort laser pulses, two different analytical models have been studied in detail. Their ability to reproduce the streak deflectometry measurements was tested on the basis of three-dimensional particle simulations. A modification and combination of the two models allowed for an extensive and accurate reproduction of the experimental results in both imaging configurations. The controlled change of the laser pulse duration from 50 femtoseconds to 2.7 picoseconds led to a transition of the dominating force acting on the probing proton beam at the rear side of the polymer foil. In the picosecond case the (v ⇀ x B ⇀ ) -term of the Lorentz force dominated over the counteracting E ⇀-field and was responsible for the direction of the net force. The applied proton deflectometry method allowed for an unambiguous determination of the magnetic field polarity at the rear side of the ultrathin foil.

  5. Directing Performers for the Cameras.

    Science.gov (United States)

    Wilson, George P., Jr.

    An excellent way for an undergraduate, novice director of television and film to pick up background experience in directing performers for cameras is by participating in nonbroadcast-film activities, such as theatre, dance, and variety acts, both as performer and as director. This document describes the varieties of activities, including creative,…

  6. The Camera Comes to Court.

    Science.gov (United States)

    Floren, Leola

    After the Lindbergh kidnapping trial in 1935, the American Bar Association sought to eliminate electronic equipment from courtroom proceedings. Eventually, all but two states adopted regulations applying that ban to some extent, and a 1965 Supreme Court decision encouraged the banning of television cameras at trials as well. Currently, some states…

  7. Digital Low Frequency Radio Camera

    Science.gov (United States)

    Fullekrug, M.; Mezentsev, A.; Soula, S.; van der Velde, O.; Poupeney, J.; Sudre, C.; Gaffet, S.; Pincon, J.

    2012-04-01

    This contribution reports the design, realization and operation of a novel digital low frequency radio camera towards an exploration of the Earth's electromagnetic environment with particular emphasis on lightning discharges and subsequent atmospheric effects such as transient luminous events. The design of the digital low frequency radio camera is based on the idea of radio interferometry with a network of radio receivers which are separated by spatial baselines comparable to the wavelength of the observed radio waves, i.e., ~1-100 km which corresponds to a frequency range from ~3-300 kHz. The key parameter towards the realization of the radio interferometer is the frequency dependent slowness of the radio waves within the Earth's atmosphere with respect to the speed of light in vacuum. This slowness is measured with the radio interferometer by using well documented radio transmitters. The digital low frequency radio camera can be operated in different modes. In the imaging mode, still photographs show maps of the low frequency radio sky. In the video mode, movies show the dynamics of the low frequency radio sky. The exposure time of the photograhps, the frame rate of the video, and the radio frequency of interest can be adjusted by the observer. Alternatively, the digital radio camera can be used in the monitoring mode, where a particular area of the sky is observed continuously. The first application of the digital low frequency radio camera is to characterize the electromagnetic energy emanating from sprite producing lightning discharges, but it is expected that it can also be used to identify and investigate numerous other radio sources of the Earth's electromagnetic environment.

  8. Time-resolved demagnetization of Co{sub 2}MnSi observed using x-ray magnetic circular dichroism and an ultrafast streak camera

    Energy Technology Data Exchange (ETDEWEB)

    Opachich, Y P; Young, A T; Scholl, A; Feng, J; Engelhorn, K; Padmore, H A [Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8099 (United States); Comin, A; Reiss, G [Italian Institute of Technology, Nanophys, 16163 Genova GE (Italy); Bartelt, A F [Department of Materials for Photovoltaics, Helmholtz Center Berlin for Materials and Energy, 14109 Berlin (Germany); Schmalhorst, J [Department of Physics, Bielefeld University, 33501 Bielefeld (Germany); Shin, H J [Pohang Accelerator Laboratory, Pohang University of Science and Technology, Kyungbuk 790-784 (Korea, Republic of); Risbud, S H, E-mail: YPOpachich@gmail.co [Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, CA 95616 (United States)

    2010-04-21

    The demagnetization dynamics of the Heusler alloy Co{sub 2}MnSi was studied using picosecond time-resolved x-ray magnetic circular dichroism. The sample was excited using femtosecond laser pulses. In contrast to the sub-picosecond demagnetization of the metal ferromagnet Ni, substantially slower demagnetization with a time constant of 3.5 +- 0.5 ps was measured. This could be explained by a spin-dependent band gap inhibiting the spin-flip scattering of hot electrons in Co{sub 2}MnSi, which is predicted to be half-metallic. A universal demagnetization time constant was measured across a range of pump power levels.

  9. Dynamic Camera Positioning and Reconfiguration for Multi-Camera Networks

    OpenAIRE

    Konda, Krishna Reddy

    2015-01-01

    The large availability of different types of cameras and lenses, together with the reduction in price of video sensors, has contributed to a widespread use of video surveillance systems, which have become a widely adopted tool to enforce security and safety, in detecting and preventing crimes and dangerous events. The possibility for personalization of such systems is generally very high, letting the user customize the sensing infrastructure, and deploying ad-hoc solutions based on the curren...

  10. An optical metasurface planar camera

    CERN Document Server

    Arbabi, Amir; Kamali, Seyedeh Mahsa; Horie, Yu; Han, Seunghoon; Faraon, Andrei

    2016-01-01

    Optical metasurfaces are 2D arrays of nano-scatterers that modify optical wavefronts at subwavelength spatial resolution. They are poised to revolutionize optical design by enabling complex low cost systems where multiple metasurfaces are lithographically stacked on top of each other and are integrated with electronics. For imaging applications, metasurface stacks can perform sophisticated image corrections and can be directly integrated with image sensors. Here, we demonstrate this concept with a miniature flat camera integrating a monolithic metasurface lens doublet corrected for monochromatic aberrations, and an image sensor. The doublet lens, which acts as a fisheye photographic objective, has an f-number of 0.9, an angle-of-view larger than 60$^\\circ$$\\times$60$^\\circ$, and operates at 850 nm wavelength with large transmission. The camera exhibits high image quality, which indicates the potential of this technology to produce a paradigm shift in future designs of imaging systems for microscopy, photograp...

  11. GRAVITY acquisition camera: characterization results

    Science.gov (United States)

    Anugu, Narsireddy; Garcia, Paulo; Amorim, Antonio; Wiezorrek, Erich; Wieprecht, Ekkehard; Eisenhauer, Frank; Ott, Thomas; Pfuhl, Oliver; Gordo, Paulo; Perrin, Guy; Brandner, Wolfgang; Straubmeier, Christian; Perraut, Karine

    2016-08-01

    GRAVITY acquisition camera implements four optical functions to track multiple beams of Very Large Telescope Interferometer (VLTI): a) pupil tracker: a 2×2 lenslet images four pupil reference lasers mounted on the spiders of telescope secondary mirror; b) field tracker: images science object; c) pupil imager: reimages telescope pupil; d) aberration tracker: images a Shack-Hartmann. The estimation of beam stabilization parameters from the acquisition camera detector image is carried out, for every 0.7 s, with a dedicated data reduction software. The measured parameters are used in: a) alignment of GRAVITY with the VLTI; b) active pupil and field stabilization; c) defocus correction and engineering purposes. The instrument is now successfully operational on-sky in closed loop. The relevant data reduction and on-sky characterization results are reported.

  12. SPEIR: A Ge Compton Camera

    Energy Technology Data Exchange (ETDEWEB)

    Mihailescu, L; Vetter, K M; Burks, M T; Hull, E L; Craig, W W

    2004-02-11

    The SPEctroscopic Imager for {gamma}-Rays (SPEIR) is a new concept of a compact {gamma}-ray imaging system of high efficiency and spectroscopic resolution with a 4-{pi} field-of-view. The system behind this concept employs double-sided segmented planar Ge detectors accompanied by the use of list-mode photon reconstruction methods to create a sensitive, compact Compton scatter camera.

  13. Graphic design of pinhole cameras

    Science.gov (United States)

    Edwards, H. B.; Chu, W. P.

    1979-01-01

    The paper describes a graphic technique for the analysis and optimization of pinhole size and focal length. The technique is based on the use of the transfer function of optical elements described by Scott (1959) to construct the transfer function of a circular pinhole camera. This transfer function is the response of a component or system to a pattern of lines having a sinusoidally varying radiance at varying spatial frequencies. Some specific examples of graphic design are presented.

  14. Coordinated Sensing in Intelligent Camera Networks

    OpenAIRE

    Ding, Chong

    2013-01-01

    The cost and size of video sensors has led to camera networks becoming pervasive in our lives. However, the ability to analyze these images efficiently is very much a function of the quality of the acquired images. Human control of pan-tilt-zoom (PTZ) cameras is impractical and unreliable when high quality images are needed of multiple events distributed over a large area. This dissertation considers the problem of automatically controlling the fields of view of individual cameras in a camera...

  15. Optimising Camera Traps for Monitoring Small Mammals

    OpenAIRE

    Glen, Alistair S.; Stuart Cockburn; Margaret Nichols; Jagath Ekanayake; Bruce Warburton

    2013-01-01

    Practical techniques are required to monitor invasive animals, which are often cryptic and occur at low density. Camera traps have potential for this purpose, but may have problems detecting and identifying small species. A further challenge is how to standardise the size of each camera?s field of view so capture rates are comparable between different places and times. We investigated the optimal specifications for a low-cost camera trap for small mammals. The factors tested were 1) trigger s...

  16. Stereo Pinhole Camera: Assembly and experimental activities

    OpenAIRE

    Santos, Gilmário Barbosa; Departamento de Ciência da Computação, Universidade do Estado de Santa Catarina, Joinville; Cunha, Sidney Pinto; Centro de Tecnologia da Informação Renato Archer, Campinas

    2015-01-01

    This work describes the assembling of a stereo pinhole camera for capturing stereo-pairs of images and proposes experimental activities with it. A pinhole camera can be as sophisticated as you want, or so simple that it could be handcrafted with practically recyclable materials. This paper describes the practical use of the pinhole camera throughout history and currently. Aspects of optics and geometry involved in the building of the stereo pinhole camera are presented with illustrations. Fur...

  17. Recombination hotspots and host susceptibility modulate the adaptive value of recombination during maize streak virus evolution

    Directory of Open Access Journals (Sweden)

    Monjane Adérito L

    2011-12-01

    Full Text Available Abstract Background Maize streak virus -strain A (MSV-A; Genus Mastrevirus, Family Geminiviridae, the maize-adapted strain of MSV that causes maize streak disease throughout sub-Saharan Africa, probably arose between 100 and 200 years ago via homologous recombination between two MSV strains adapted to wild grasses. MSV recombination experiments and analyses of natural MSV recombination patterns have revealed that this recombination event entailed the exchange of the movement protein - coat protein gene cassette, bounded by the two genomic regions most prone to recombination in mastrevirus genomes; the first surrounding the virion-strand origin of replication, and the second around the interface between the coat protein gene and the short intergenic region. Therefore, aside from the likely adaptive advantages presented by a modular exchange of this cassette, these specific breakpoints may have been largely predetermined by the underlying mechanisms of mastrevirus recombination. To investigate this hypothesis, we constructed artificial, low-fitness, reciprocal chimaeric MSV genomes using alternating genomic segments from two MSV strains; a grass-adapted MSV-B, and a maize-adapted MSV-A. Between them, each pair of reciprocal chimaeric genomes represented all of the genetic material required to reconstruct - via recombination - the highly maize-adapted MSV-A genotype, MSV-MatA. We then co-infected a selection of differentially MSV-resistant maize genotypes with pairs of reciprocal chimaeras to determine the efficiency with which recombination would give rise to high-fitness progeny genomes resembling MSV-MatA. Results Recombinants resembling MSV-MatA invariably arose in all of our experiments. However, the accuracy and efficiency with which the MSV-MatA genotype was recovered across all replicates of each experiment depended on the MSV susceptibility of the maize genotypes used and the precise positions - in relation to known recombination hotspots

  18. Toward a miniaturized fundus camera.

    Science.gov (United States)

    Gliss, Christine; Parel, Jean-Marie; Flynn, John T; Pratisto, Hans; Niederer, Peter

    2004-01-01

    Retinopathy of prematurity (ROP) describes a pathological development of the retina in prematurely born children. In order to prevent severe permanent damage to the eye and enable timely treatment, the fundus of the eye in such children has to be examined according to established procedures. For these examinations, our miniaturized fundus camera is intended to allow the acquisition of wide-angle digital pictures of the fundus for on-line or off-line diagnosis and documentation. We designed two prototypes of a miniaturized fundus camera, one with graded refractive index (GRIN)-based optics, the other with conventional optics. Two different modes of illumination were compared: transscleral and transpupillary. In both systems, the size and weight of the camera were minimized. The prototypes were tested on young rabbits. The experiments led to the conclusion that the combination of conventional optics with transpupillary illumination yields the best results in terms of overall image quality. (c) 2004 Society of Photo-Optical Instrumentation Engineers.

  19. 16 CFR 501.1 - Camera film.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Camera film. 501.1 Section 501.1 Commercial... 500 § 501.1 Camera film. Camera film packaged and labeled for retail sale is exempt from the net... should be expressed, provided: (a) The net quantity of contents on packages of movie film and bulk still...

  20. An Open Standard for Camera Trap Data

    NARCIS (Netherlands)

    Forrester, Tavis; O'Brien, Tim; Fegraus, Eric; Jansen, P.A.; Palmer, Jonathan; Kays, Roland; Ahumada, Jorge; Stern, Beth; McShea, William

    2016-01-01

    Camera traps that capture photos of animals are a valuable tool for monitoring biodiversity. The use of camera traps is rapidly increasing and there is an urgent need for standardization to facilitate data management, reporting and data sharing. Here we offer the Camera Trap Metadata Standard as an

  1. 21 CFR 892.1110 - Positron camera.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Positron camera. 892.1110 Section 892.1110 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1110 Positron camera. (a) Identification. A positron camera is a device intended to image the distribution of positron-emitting radionuclides in the body...

  2. 21 CFR 886.1120 - Opthalmic camera.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Opthalmic camera. 886.1120 Section 886.1120 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1120 Opthalmic camera. (a) Identification. An ophthalmic camera is an AC-powered device intended to take photographs of the eye and the surrounding area...

  3. Transmission of Rice Black-Streaked Dwarf Virus from Frozen Infected Leaves to Healthy Rice Plants by Small Brown Planthopper (Laodelphax striatellus

    Directory of Open Access Journals (Sweden)

    Tong ZHOU

    2011-06-01

    Full Text Available In order to preserve virus for identifying the resistance of rice varieties against rice black-streaked dwarf disease, a simple and reliable method was developed, through which virus-free small brown planthopper (SBPH acquired rice black-streaked dwarf virus (RBSDV from frozen infected leaves and the virus was transmitted to healthy rice plants. The experimental results showed that SBPH could obtain RBSDV from frozen infected rice leaves and the virus could be transmitted to a susceptible rice variety. For the ability to acquire RBSDV and transmit the virus to healthy plants by SBPH, there was no significant difference between frozen infected leaves and in vitro infected leaves. The novel method could be applied to identification of rice variety resistance to rice black-streaked dwarf disease, facilitating the breeding process for rice black-streaked dwarf disease resistance.

  4. Relative camera localisation in non-overlapping camera networks using multiple trajectories

    NARCIS (Netherlands)

    John, V.; Englebienne, G.; Kröse, B.J.A.

    2012-01-01

    In this article we present an automatic camera calibration algorithm using multiple trajectories in a multiple camera network with non-overlapping field-of-views (FOV). Visible trajectories within a camera FOV are assumed to be measured with respect to the camera local co-ordinate system.

  5. Use of the Coelomic Grafting Technique for Prolonged ex utero Cultivation of Late Preprimitive Streak-Stage Rabbit Embryos.

    Science.gov (United States)

    Püschel, Bernd; Männer, Jörg

    2016-01-01

    Due to its morphological similarity with the early human embryo, the pregastrulation-stage rabbit may represent an appropriate mammalian model for studying processes involved in early human development. The usability of mammalian embryos for experimental studies depends on the availability of whole embryo culture methods facilitating prolonged ex utero development. While currently used culture methods yield high success rates for embryos from primitive streak stages onward, the success rate of extended cultivation of preprimitive streak-stage mammalian embryos is low for all previously established methods and for all studied species. This limits the usability of preprimitive streak-stage rabbit embryos in experimental embryology. We have tested whether the extraembryonic coelom of 4-day-old chick embryos may be used for prolonged ex utero culture of preprimitive streak-stage rabbit embryos (stage 2, 6.2 days post coitum). We found that, within this environment, stage 2 rabbit blastocysts can be cultured at decreasing success rates (55% after 1 day, 35% after 2 days, 15% after 3 days) up to a maximum of 72 h. Grafted blastocysts can continue development from the onset of gastrulation to early organogenesis and thereby form all structures characterizing age-matched controls (e.g. neural tube, somites, beating heart). Compared to normal controls, successfully cultured embryos developed at a slower rate and finally showed some structural and gross morphological anomalies. The method presented here was originally developed for whole embryo culture of mouse embryos by Gluecksohn-Schoenheimer in 1941. It is a simple and inexpensive method that may represent a useful extension to presently available ex utero culture systems for rabbit embryos. © 2016 S. Karger AG, Basel.

  6. Automatic detection of Martian dark slope streaks by machine learning using HiRISE images

    Science.gov (United States)

    Wang, Yexin; Di, Kaichang; Xin, Xin; Wan, Wenhui

    2017-07-01

    Dark slope streaks (DSSs) on the Martian surface are one of the active geologic features that can be observed on Mars nowadays. The detection of DSS is a prerequisite for studying its appearance, morphology, and distribution to reveal its underlying geological mechanisms. In addition, increasingly massive amounts of Mars high resolution data are now available. Hence, an automatic detection method for locating DSSs is highly desirable. In this research, we present an automatic DSS detection method by combining interest region extraction and machine learning techniques. The interest region extraction combines gradient and regional grayscale information. Moreover, a novel recognition strategy is proposed that takes the normalized minimum bounding rectangles (MBRs) of the extracted regions to calculate the Local Binary Pattern (LBP) feature and train a DSS classifier using the Adaboost machine learning algorithm. Comparative experiments using five different feature descriptors and three different machine learning algorithms show the superiority of the proposed method. Experimental results utilizing 888 extracted region samples from 28 HiRISE images show that the overall detection accuracy of our proposed method is 92.4%, with a true positive rate of 79.1% and false positive rate of 3.7%, which in particular indicates great performance of the method at eliminating non-DSS regions.

  7. Lucerne transient streak virus; a Recently Detected Virus Infecting Alfafa (Medicago sativa in Central Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Ahmed Raza

    2017-02-01

    Full Text Available A survey was conducted to determine the status of Lucerne transient streak virus (LTSV in three high-yielding alfalfa regions in central Saudi Arabia (Riyadh, Qassim, and Hail during 2014. Three hundred and eight symptomatic alfalfa, and seven Sonchus oleraceus samples were collected. DAS-ELISA indicated that 59 of these samples were positive to LTSV. Two isolates of LTSV from each region were selected for molecular studies. RT-PCR confirmed the presence of LTSV in the selected samples using a specific primer pair. Percentage identity and homology tree comparisons revealed that all Saudi isolates were more closely related to each other but also closely related to the Canadian isolate-JQ782213 (97.1–97.6% and the New Zealand isolate-U31286 (95.8–97.1%. Comparing Saudi isolates of LTSV with ten other sobemoviruses based on the coat protein gene sequences confirmed the distant relationship between them. Eleven out of fourteen plant species used in host range study were positive to LTSV. This is the first time to document that Trifolium alexandrinum, Nicotiana occidentalis, Chenopodium glaucum, and Lathyrus sativus are new host plant species for LTSV and that N. occidentalis being a good propagative host for it.

  8. Improving the diffraction of full-length human selenomethionyl metavinculin crystals by streak-seeding

    Energy Technology Data Exchange (ETDEWEB)

    Rangarajan, Erumbi S.; Izard, Tina (Scripps)

    2012-06-28

    Metavinculin is an alternatively spliced isoform of vinculin that has a 68-residue insert in its tail domain (1134 total residues) and is exclusively expressed in cardiac and smooth muscle tissue, where it plays important roles in myocyte adhesion complexes. Mutations in the metavinculin-specific insert are associated with dilated cardiomyopathy (DCM) in man. Crystals of a DCM-associated mutant of full-length selenomethionine-labeled metavinculin grown by hanging-drop vapor diffusion diffracted poorly and were highly sensitive to radiation, preventing the collection of a complete X-ray diffraction data set at the highest possible resolution. Streak-seeding markedly improved the stability, crystal-growth rate and diffraction quality of DCM-associated mutant metavinculin crystals, allowing complete data collection to 3.9 {angstrom} resolution. These crystals belonged to space group P4{sub 3}2{sub 1}2, with two molecules in the asymmetric unit and unit-cell parameters a = b = 170, c = 211 {angstrom}, {alpha} = {beta} = {gamma} = 90{sup o}.

  9. Progressive symmetric vertical macular wide angioid streak-like lacquer crack

    Directory of Open Access Journals (Sweden)

    Mansour AM

    2016-04-01

    Full Text Available Ahmad M Mansour1,2 1Department of Ophthalmology, American University of Beirut, 2Department of Ophthalmology, Rafic Hariri University Hospital, Beirut, Lebanon Purpose: We report an unusual case of bilateral vertical lacquer crack with no history of ocular trauma and with progressive marked enlargement and consequent visual loss. Methods: Three-year follow-up was completed using best-corrected visual acuity, serial fundus photographs, intravenous fluorescein angiography, and optical coherence tomography. Results: We report the occurrence of lacquer crack in a 43-year-old woman with no history of trauma except for laser in situ keratomileusis surgery for mild myopia (as reported by the patient in the past 5 years and habitual ocular rubbing. Lacquer crack started in the right eye and became evident 1 year later in the left eye. Serial photography after repeated intravitreal injections of ranibizumab for subfoveal choroidal new vessel showed the lacquer crack widened gradually in both eyes. Axial length measurement revealed the presence of high myopia. Best-corrected visual acuity dropped to 20/200 bilaterally. Conclusion: We hypothesize that a thin Bruch's membrane in high myopia is prone for small rupture initially either spontaneously or following laser in situ keratomileusis and subsequent widening of the rupture by oculopression and intravitreal injections from rise in intraocular pressure. Keywords: angioid streak, Bruch's membrane rupture, choroidal rupture, choroidal neovascularization, high myopia, lacquer crack, LASIK

  10. Improved detection of episomal Banana streak viruses by multiplex immunocapture PCR.

    Science.gov (United States)

    Le Provost, Grégoire; Iskra-Caruana, Marie-Line; Acina, Isabelle; Teycheney, Pierre-Yves

    2006-10-01

    Banana streak viruses (BSV) are currently the main viral constraint to Musa germplasm movement, genetic improvement and mass propagation. Therefore, it is necessary to develop and implement BSV detection strategies that are both reliable and sensitive, such as PCR-based techniques. Unfortunately, BSV endogenous pararetrovirus sequences (BSV EPRVs) are present in the genome of Musa balbisiana. They interfere with PCR-based detection of episomal BSV in infected banana and plantain, such as immunocapture PCR. Therefore, a multiplex, immunocapture PCR (M-IC-PCR) was developed for the detection of BSV. Musa sequence tagged microsatellite site (STMS) primers were selected and used in combination with BSV species-specific primers in order to monitor possible contamination by Musa genomic DNA, using multiplex PCR. Furthermore, immunocapture conditions were optimized in order to prevent Musa DNA from interfering with episomal BSV DNA during the PCR step. This improved detection method successfully allowed the accurate, specific and sensitive detection of episomal DNA only from distinct BSV species. Its implementation should benefit PCR-based detection of viruses for which homologous sequences are present in the genome of their hosts, including transgenic plants expressing viral sequences.

  11. Cassava brown streak disease: historical timeline, current knowledge and future prospects.

    Science.gov (United States)

    Tomlinson, Katie R; Bailey, Andy M; Alicai, Titus; Seal, Sue; Foster, Gary D

    2017-09-08

    Cassava is the second most important staple food crop in terms of per capita calories consumed in Africa and holds potential for climate change adaptation. Unfortunately, productivity in East and Central Africa is severely constrained by two viral diseases: cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). CBSD was first reported in 1936 from northeast Tanzania. For approximately seventy years CBSD was restricted to coastal East Africa and so had a relatively low impact on food security compared to CMD. However, at the turn of the 21st century CBSD re-emerged further inland, in areas around Lake Victoria and it has since spread through many East and Central African countries, causing high yield losses and jeopardising the food security of subsistence farmers. This recent re-emergence has attracted intense scientific interest, with studies shedding light on CBSD viral epidemiology, sequence diversity, host interactions and potential sources of resistance within the cassava genome. This review reflects on 80 years of CBSD research history (1936 - 2016) with a timeline of key events. We provide insights into current CBSD knowledge, management efforts and future prospects for improved understanding needed to underpin effective control and mitigation of impacts on food security. This article is protected by copyright. All rights reserved. © 2017 BSPP and John Wiley & Sons Ltd.

  12. A simple, novel and high efficiency sap inoculation method to screen for tobacco streak virus.

    Science.gov (United States)

    Sundaresha, S; Sreevathsa, Rohini; Balol, Gurupada B; Keshavareddy, G; Rangaswamy, K T; Udayakumar, M

    2012-10-01

    A rapid and efficient sap inoculation method for tobacco streak virus (TSV) was developed in sunflower. Sap from TSV-infected sunflower plants was freshly extracted in phosphate buffer and diluted serially from 10(-1) to 10(-8). Two-day old seedlings of sunflower were injured at the meristem and immersed in the sap for 10 min, maintained at 20 °C for 2-3 days and shifted to greenhouse. The surviving seedlings in the respective sap dilution were scored for symptoms of sunflower necrosis disease (SND). SND symptoms were seen in 80 % of the seedlings inoculated with a sap dilution of 10(-5). ELISA and RT-PCR analysis of coat protein and movement protein of TSV confirmed SND symptoms. The methodology was also found to be reproducible when the sap from the infected plants was inoculated onto healthy plants. The main aim of the study was to develop a primary screening strategy for the selection of transgenics developed for SND resistance. This methodology can also be extended for the analysis of resistance against other viruses.

  13. Streaks of Life: The Introduction and Translation of a Passage from the Autobiography of Ethel Smyth

    Directory of Open Access Journals (Sweden)

    Nina Dragičević

    2015-09-01

    Full Text Available In the translated passage, taken from the autobiography of Ethel Smyth, Streaks of Life, the author writes about the position of women in music, her own position—that of a female composer in the early 20th century England. The author speaks of terror and the patronizing diction of patriarchal society. She continues with a critique of media representations, but mostly focuses on difficulties in the attempts to place one’s (woman’s artwork in public space. Despite the fact that she was romantically involved with women throughout her life and wrote about them in her other autobiographical texts, she refuses to connect lesbian identity with her work—perhaps the reason lies in the ‘safety’ of being in a closet, or because of her perceived irrelevance of lesbian identities towards artist’s output. What she emphasizes more is a woman’s perspective—reasonably so, since she was deeply involved with the suffrage movement. In her descriptions, she considers economic and political contexts of the First World War era, which gave the opportunity of holding a (temporary job for women—both in factories and in orchestras. At the end, she returns to specifics of women’s position in society, and calls for a rebellion against the tyranny of the patriarchy.

  14. Effect of rosella extract on development of fatty streaks lesions in female rats

    Directory of Open Access Journals (Sweden)

    E. R. Al-Kennany

    2010-01-01

    Full Text Available This research was conducted to explore the effect of rosella (Hibiscus sabdariffa on female rats on oxidative stress which induced by 0.5% H2O2. Oxidative stress has been investigated via tissue (aorta and heart malonadyaldehyde (MDA as indirect lipid peroxidation index. For atherosclerotic lesions follow up light microscopical technique has been applied. The result elucidate significant reduction in lipid profit parameters namely: low density lipoprotein (LDL-c, triglycerides, very low density lipoprotein (vLDL-c, atherogenic index and significant elevation in high density lipoprotein (HDL-c in few animals treated with H2O2 and rosella extract, parallely, this research illustrate reduction in aorta and heart MDA concentration, concomitant with significant rising in glutathione (GSH level. Histopathologically, this study revealed fatty streaks associated with infiltration of mononuclear inflammatory cells have been detected after 60 days, in animal treated with rosella revealed reduction in lipid vacuoles and proliferation in vascular smooth muscle cells (VSMcs in media toward intimal layers after 40 days from treatment.

  15. Hairpin RNA Targeting Multiple Viral Genes Confers Strong Resistance to Rice Black-Streaked Dwarf Virus

    Directory of Open Access Journals (Sweden)

    Fangquan Wang

    2016-05-01

    Full Text Available Rice black-streaked dwarf virus (RBSDV belongs to the genus Fijivirus in the family of Reoviridae and causes severe yield loss in rice-producing areas in Asia. RNA silencing, as a natural defence mechanism against plant viruses, has been successfully exploited for engineering virus resistance in plants, including rice. In this study, we generated transgenic rice lines harbouring a hairpin RNA (hpRNA construct targeting four RBSDV genes, S1, S2, S6 and S10, encoding the RNA-dependent RNA polymerase, the putative core protein, the RNA silencing suppressor and the outer capsid protein, respectively. Both field nursery and artificial inoculation assays of three generations of the transgenic lines showed that they had strong resistance to RBSDV infection. The RBSDV resistance in the segregating transgenic populations correlated perfectly with the presence of the hpRNA transgene. Furthermore, the hpRNA transgene was expressed in the highly resistant transgenic lines, giving rise to abundant levels of 21–24 nt small interfering RNA (siRNA. By small RNA deep sequencing, the RBSDV-resistant transgenic lines detected siRNAs from all four viral gene sequences in the hpRNA transgene, indicating that the whole chimeric fusion sequence can be efficiently processed by Dicer into siRNAs. Taken together, our results suggest that long hpRNA targeting multiple viral genes can be used to generate stable and durable virus resistance in rice, as well as other plant species.

  16. Combination treatment of low fluence photodynamic therapy and intravitreal ranibizumab for choroidal neovascular membrane secondary to angioid streaks in Paget′s disease - 12 month results

    Directory of Open Access Journals (Sweden)

    Varsha V Prabhu

    2011-01-01

    Full Text Available Angioid streaks also called Knapp striae are small breaks in the Bruch′s membrane and have been reported with a host of systemic diseases. Rupture of streaks or development of secondary choroidal neovascular membrane (CNVM carries a dismal visual prognosis. We report the successful treatment of CNVM secondary to Paget′s disease using low fluence photodynamic therapy (PDT and intravitreal ranibizumab.

  17. Transmission of Rice Black-Streaked Dwarf Virus from Frozen Infected Leaves to Healthy Rice Plants by Small Brown Planthopper (Laodelphax striatellus)

    OpenAIRE

    Zhou, Tong; Wu, Li-juan; Wang, Ying; Cheng, Zhao-Bang; Ji, Ying-Hua; Yong-jian FAN; Zhou, Yi-Jun

    2011-01-01

    In order to preserve virus for identifying the resistance of rice varieties against rice black-streaked dwarf disease, a simple and reliable method was developed, through which virus-free small brown planthopper (SBPH) acquired rice black-streaked dwarf virus (RBSDV) from frozen infected leaves and the virus was transmitted to healthy rice plants. The experimental results showed that SBPH could obtain RBSDV from frozen infected rice leaves and the virus could be transmitted to a susceptible r...

  18. Statistical iterative reconstruction for streak artefact reduction when using multidetector CT to image the dento-alveolar structures

    Science.gov (United States)

    Hayakawa, Y; Kober, C

    2014-01-01

    Objectives: When metallic prosthetic appliances and dental fillings exist in the oral cavity, the appearance of metal-induced streak artefacts is not avoidable in CT images. The aim of this study was to develop a method for artefact reduction using the statistical reconstruction on multidetector row CT images. Methods: Adjacent CT images often depict similar anatomical structures. Therefore, reconstructed images with weak artefacts were attempted using projection data of an artefact-free image in a neighbouring thin slice. Images with moderate and strong artefacts were continuously processed in sequence by successive iterative restoration where the projection data was generated from the adjacent reconstructed slice. First, the basic maximum likelihood–expectation maximization algorithm was applied. Next, the ordered subset–expectation maximization algorithm was examined. Alternatively, a small region of interest setting was designated. Finally, the general purpose graphic processing unit machine was applied in both situations. Results: The algorithms reduced the metal-induced streak artefacts on multidetector row CT images when the sequential processing method was applied. The ordered subset–expectation maximization and small region of interest reduced the processing duration without apparent detriments. A general-purpose graphic processing unit realized the high performance. Conclusions: A statistical reconstruction method was applied for the streak artefact reduction. The alternative algorithms applied were effective. Both software and hardware tools, such as ordered subset–expectation maximization, small region of interest and general-purpose graphic processing unit achieved fast artefact correction. PMID:24754471

  19. Robot Tracer with Visual Camera

    Science.gov (United States)

    Jabbar Lubis, Abdul; Dwi Lestari, Yuyun; Dafitri, Haida; Azanuddin

    2017-12-01

    Robot is a versatile tool that can function replace human work function. The robot is a device that can be reprogrammed according to user needs. The use of wireless networks for remote monitoring needs can be utilized to build a robot that can be monitored movement and can be monitored using blueprints and he can track the path chosen robot. This process is sent using a wireless network. For visual robot using high resolution cameras to facilitate the operator to control the robot and see the surrounding circumstances.

  20. Human tracking over camera networks: a review

    Science.gov (United States)

    Hou, Li; Wan, Wanggen; Hwang, Jenq-Neng; Muhammad, Rizwan; Yang, Mingyang; Han, Kang

    2017-12-01

    In recent years, automated human tracking over camera networks is getting essential for video surveillance. The tasks of tracking human over camera networks are not only inherently challenging due to changing human appearance, but also have enormous potentials for a wide range of practical applications, ranging from security surveillance to retail and health care. This review paper surveys the most widely used techniques and recent advances for human tracking over camera networks. Two important functional modules for the human tracking over camera networks are addressed, including human tracking within a camera and human tracking across non-overlapping cameras. The core techniques of human tracking within a camera are discussed based on two aspects, i.e., generative trackers and discriminative trackers. The core techniques of human tracking across non-overlapping cameras are then discussed based on the aspects of human re-identification, camera-link model-based tracking and graph model-based tracking. Our survey aims to address existing problems, challenges, and future research directions based on the analyses of the current progress made toward human tracking techniques over camera networks.

  1. Using DSLR cameras in digital holography

    Science.gov (United States)

    Hincapié-Zuluaga, Diego; Herrera-Ramírez, Jorge; García-Sucerquia, Jorge

    2017-08-01

    In Digital Holography (DH), the size of the bidimensional image sensor to record the digital hologram, plays a key role on the performance of this imaging technique; the larger the size of the camera sensor, the better the quality of the final reconstructed image. Scientific cameras with large formats are offered in the market, but their cost and availability limit their use as a first option when implementing DH. Nowadays, DSLR cameras provide an easy-access alternative that is worthwhile to be explored. The DSLR cameras are a wide, commercial, and available option that in comparison with traditional scientific cameras, offer a much lower cost per effective pixel over a large sensing area. However, in the DSLR cameras, with their RGB pixel distribution, the sampling of information is different to the sampling in monochrome cameras usually employed in DH. This fact has implications in their performance. In this work, we discuss why DSLR cameras are not extensively used for DH, taking into account the problem reported by different authors of object replication. Simulations of DH using monochromatic and DSLR cameras are presented and a theoretical deduction for the replication problem using the Fourier theory is also shown. Experimental results of DH implementation using a DSLR camera show the replication problem.

  2. Optimising camera traps for monitoring small mammals.

    Directory of Open Access Journals (Sweden)

    Alistair S Glen

    Full Text Available Practical techniques are required to monitor invasive animals, which are often cryptic and occur at low density. Camera traps have potential for this purpose, but may have problems detecting and identifying small species. A further challenge is how to standardise the size of each camera's field of view so capture rates are comparable between different places and times. We investigated the optimal specifications for a low-cost camera trap for small mammals. The factors tested were 1 trigger speed, 2 passive infrared vs. microwave sensor, 3 white vs. infrared flash, and 4 still photographs vs. video. We also tested a new approach to standardise each camera's field of view. We compared the success rates of four camera trap designs in detecting and taking recognisable photographs of captive stoats (Mustelaerminea, feral cats (Felis catus and hedgehogs (Erinaceuseuropaeus. Trigger speeds of 0.2-2.1 s captured photographs of all three target species unless the animal was running at high speed. The camera with a microwave sensor was prone to false triggers, and often failed to trigger when an animal moved in front of it. A white flash produced photographs that were more readily identified to species than those obtained under infrared light. However, a white flash may be more likely to frighten target animals, potentially affecting detection probabilities. Video footage achieved similar success rates to still cameras but required more processing time and computer memory. Placing two camera traps side by side achieved a higher success rate than using a single camera. Camera traps show considerable promise for monitoring invasive mammal control operations. Further research should address how best to standardise the size of each camera's field of view, maximise the probability that an animal encountering a camera trap will be detected, and eliminate visible or audible cues emitted by camera traps.

  3. Closed-loop control of boundary layer streaks induced by free-stream turbulence

    Science.gov (United States)

    Papadakis, George; Lu, Liang; Ricco, Pierre

    2016-08-01

    The central aim of the paper is to carry out a theoretical and numerical study of active wall transpiration control of streaks generated within an incompressible boundary layer by free-stream turbulence. The disturbance flow model is based on the linearized unsteady boundary-region (LUBR) equations, studied by Leib, Wundrow, and Goldstein [J. Fluid Mech. 380, 169 (1999), 10.1017/S0022112098003504], which are the rigorous asymptotic limit of the Navier-Stokes equations for low-frequency and long-streamwise wavelength. The mathematical formulation of the problem directly incorporates the random forcing into the equations in a consistent way. Due to linearity, this forcing is factored out and appears as a multiplicative factor. It is shown that the cost function (integral of kinetic energy in the domain) is properly defined as the expectation of a random quadratic function only after integration in wave number space. This operation naturally introduces the free-stream turbulence spectral tensor into the cost function. The controller gains for each wave number are independent of the spectral tensor and, in that sense, universal. Asymptotic matching of the LUBR equations with the free-stream conditions results in an additional forcing term in the state-space system whose presence necessitates the reformulation of the control problem and the rederivation of its solution. It is proved that the solution can be obtained analytically using an extension of the sweep method used in control theory to obtain the standard Riccati equation. The control signal consists of two components, a feedback part and a feed-forward part (that depends explicitly on the forcing term). Explicit recursive equations that provide these two components are derived. It is shown that the feed-forward part makes a negligible contribution to the control signal. We also derive an explicit expression that a priori (i.e., before solving the control problem) leads to the minimum of the objective cost

  4. Experimental observations of rapid Maize streak virus evolution reveal a strand-specific nucleotide substitution bias

    Directory of Open Access Journals (Sweden)

    Varsani Arvind

    2008-09-01

    Full Text Available Abstract Background Recent reports have indicated that single-stranded DNA (ssDNA viruses in the taxonomic families Geminiviridae, Parvoviridae and Anellovirus may be evolving at rates of ~10-4 substitutions per site per year (subs/site/year. These evolution rates are similar to those of RNA viruses and are surprisingly high given that ssDNA virus replication involves host DNA polymerases with fidelities approximately 10 000 times greater than those of error-prone viral RNA polymerases. Although high ssDNA virus evolution rates were first suggested in evolution experiments involving the geminivirus maize streak virus (MSV, the evolution rate of this virus has never been accurately measured. Also, questions regarding both the mechanistic basis and adaptive value of high geminivirus mutation rates remain unanswered. Results We determined the short-term evolution rate of MSV using full genome analysis of virus populations initiated from cloned genomes. Three wild type viruses and three defective artificial chimaeric viruses were maintained in planta for up to five years and displayed evolution rates of between 7.4 × 10-4 and 7.9 × 10-4 subs/site/year. Conclusion These MSV evolution rates are within the ranges observed for other ssDNA viruses and RNA viruses. Although no obvious evidence of positive selection was detected, the uneven distribution of mutations within the defective virus genomes suggests that some of the changes may have been adaptive. We also observed inter-strand nucleotide substitution imbalances that are consistent with a recent proposal that high mutation rates in geminiviruses (and possibly ssDNA viruses in general may be due to mutagenic processes acting specifically on ssDNA molecules.

  5. Neutron Radiation Shielding For The NIF Streaked X-Ray Detector (SXD) Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Song, P; Holder, J; Young, B; Kalantar, D; Eder, D; Kimbrough, J

    2006-11-02

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is preparing for the National Ignition Campaign (NIC) scheduled in 2010. The NIC is comprised of several ''tuning'' physics subcampaigns leading up to a demonstration of Inertial Confinement Fusion (ICF) ignition. In some of these experiments, time-resolved x-ray imaging of the imploding capsule may be required to measure capsule trajectory (shock timing) or x-ray ''bang-time''. A capsule fueled with pure tritium (T) instead of a deutriun-tritium (DT) mixture is thought to offer useful physics surrogacy, with reduced yields of up to 5e14 neutrons. These measurements will require the use of the NIF streak x-ray detector (SXD). The resulting prompt neutron fluence at the planned SXD location ({approx}1.7 m from the target) would be {approx}1.4e9/cm{sup 2}. Previous measurements suggest the onset of significant background at a neutron fluence of {approx} 1e8/cm{sup 2}. The radiation damage and operational upsets which starts at {approx}1e8 rad-Si/sec must be factored into an integrated experimental campaign plan. Monte Carlo analyses were performed to predict the neutron and gamma/x-ray fluences and radiation doses for the proposed diagnostic configuration. A possible shielding configuration is proposed to mitigate radiation effects. The primary component of this shielding is an 80 cm thickness of Polyethylene (PE) between target chamber center (TCC) and the SXD diagnostic. Additionally, 6-8 cm of PE around the detector provide from the large number of neutrons that scatter off the inside of the target chamber. This proposed shielding configuration reduces the high-energy neutron fluence at the SXD by approximately a factor {approx}50.

  6. High Speed Digital Camera Technology Review

    Science.gov (United States)

    Clements, Sandra D.

    2009-01-01

    A High Speed Digital Camera Technology Review (HSD Review) is being conducted to evaluate the state-of-the-shelf in this rapidly progressing industry. Five HSD cameras supplied by four camera manufacturers participated in a Field Test during the Space Shuttle Discovery STS-128 launch. Each camera was also subjected to Bench Tests in the ASRC Imaging Development Laboratory. Evaluation of the data from the Field and Bench Tests is underway. Representatives from the imaging communities at NASA / KSC and the Optical Systems Group are participating as reviewers. A High Speed Digital Video Camera Draft Specification was updated to address Shuttle engineering imagery requirements based on findings from this HSD Review. This draft specification will serve as the template for a High Speed Digital Video Camera Specification to be developed for the wider OSG imaging community under OSG Task OS-33.

  7. Computational imaging for miniature cameras

    Science.gov (United States)

    Salahieh, Basel

    Miniature cameras play a key role in numerous imaging applications ranging from endoscopy and metrology inspection devices to smartphones and head-mount acquisition systems. However, due to the physical constraints, the imaging conditions, and the low quality of small optics, their imaging capabilities are limited in terms of the delivered resolution, the acquired depth of field, and the captured dynamic range. Computational imaging jointly addresses the imaging system and the reconstructing algorithms to bypass the traditional limits of optical systems and deliver better restorations for various applications. The scene is encoded into a set of efficient measurements which could then be computationally decoded to output a richer estimate of the scene as compared with the raw images captured by conventional imagers. In this dissertation, three task-based computational imaging techniques are developed to make low-quality miniature cameras capable of delivering realistic high-resolution reconstructions, providing full-focus imaging, and acquiring depth information for high dynamic range objects. For the superresolution task, a non-regularized direct superresolution algorithm is developed to achieve realistic restorations without being penalized by improper assumptions (e.g., optimizers, priors, and regularizers) made in the inverse problem. An adaptive frequency-based filtering scheme is introduced to upper bound the reconstruction errors while still producing more fine details as compared with previous methods under realistic imaging conditions. For the full-focus imaging task, a computational depth-based deconvolution technique is proposed to bring a scene captured by an ordinary fixed-focus camera to a full-focus based on a depth-variant point spread function prior. The ringing artifacts are suppressed on three levels: block tiling to eliminate boundary artifacts, adaptive reference maps to reduce ringing initiated by sharp edges, and block-wise deconvolution or

  8. The Mars Science Laboratory Engineering Cameras

    Science.gov (United States)

    Maki, J.; Thiessen, D.; Pourangi, A.; Kobzeff, P.; Litwin, T.; Scherr, L.; Elliott, S.; Dingizian, A.; Maimone, M.

    2012-09-01

    NASA's Mars Science Laboratory (MSL) Rover is equipped with a set of 12 engineering cameras. These cameras are build-to-print copies of the Mars Exploration Rover cameras described in Maki et al. (J. Geophys. Res. 108(E12): 8071, 2003). Images returned from the engineering cameras will be used to navigate the rover on the Martian surface, deploy the rover robotic arm, and ingest samples into the rover sample processing system. The Navigation cameras (Navcams) are mounted to a pan/tilt mast and have a 45-degree square field of view (FOV) with a pixel scale of 0.82 mrad/pixel. The Hazard Avoidance Cameras (Hazcams) are body-mounted to the rover chassis in the front and rear of the vehicle and have a 124-degree square FOV with a pixel scale of 2.1 mrad/pixel. All of the cameras utilize a 1024×1024 pixel detector and red/near IR bandpass filters centered at 650 nm. The MSL engineering cameras are grouped into two sets of six: one set of cameras is connected to rover computer "A" and the other set is connected to rover computer "B". The Navcams and Front Hazcams each provide similar views from either computer. The Rear Hazcams provide different views from the two computers due to the different mounting locations of the "A" and "B" Rear Hazcams. This paper provides a brief description of the engineering camera properties, the locations of the cameras on the vehicle, and camera usage for surface operations.

  9. Movement-based Interaction in Camera Spaces

    DEFF Research Database (Denmark)

    Eriksson, Eva; Riisgaard Hansen, Thomas; Lykke-Olesen, Andreas

    2006-01-01

    In this paper we present three concepts that address movement-based interaction using camera tracking. Based on our work with several movement-based projects we present four selected applications, and use these applications to leverage our discussion, and to describe our three main concepts space......, relations, and feedback. We see these as central for describing and analysing movement-based systems using camera tracking and we show how these three concepts can be used to analyse other camera tracking applications....

  10. Development of biostereometric experiments. [stereometric camera system

    Science.gov (United States)

    Herron, R. E.

    1978-01-01

    The stereometric camera was designed for close-range techniques in biostereometrics. The camera focusing distance of 360 mm to infinity covers a broad field of close-range photogrammetry. The design provides for a separate unit for the lens system and interchangeable backs on the camera for the use of single frame film exposure, roll-type film cassettes, or glass plates. The system incorporates the use of a surface contrast optical projector.

  11. Omnidirectional Underwater Camera Design and Calibration

    Directory of Open Access Journals (Sweden)

    Josep Bosch

    2015-03-01

    Full Text Available This paper presents the development of an underwater omnidirectional multi-camera system (OMS based on a commercially available six-camera system, originally designed for land applications. A full calibration method is presented for the estimation of both the intrinsic and extrinsic parameters, which is able to cope with wide-angle lenses and non-overlapping cameras simultaneously. This method is valid for any OMS in both land or water applications. For underwater use, a customized housing is required, which often leads to strong image distortion due to refraction among the different media. This phenomena makes the basic pinhole camera model invalid for underwater cameras, especially when using wide-angle lenses, and requires the explicit modeling of the individual optical rays. To address this problem, a ray tracing approach has been adopted to create a field-of-view (FOV simulator for underwater cameras. The simulator allows for the testing of different housing geometries and optics for the cameras to ensure a complete hemisphere coverage in underwater operation. This paper describes the design and testing of a compact custom housing for a commercial off-the-shelf OMS camera (Ladybug 3 and presents the first results of its use. A proposed three-stage calibration process allows for the estimation of all of the relevant camera parameters. Experimental results are presented, which illustrate the performance of the calibration method and validate the approach.

  12. Omnidirectional Underwater Camera Design and Calibration

    Science.gov (United States)

    Bosch, Josep; Gracias, Nuno; Ridao, Pere; Ribas, David

    2015-01-01

    This paper presents the development of an underwater omnidirectional multi-camera system (OMS) based on a commercially available six-camera system, originally designed for land applications. A full calibration method is presented for the estimation of both the intrinsic and extrinsic parameters, which is able to cope with wide-angle lenses and non-overlapping cameras simultaneously. This method is valid for any OMS in both land or water applications. For underwater use, a customized housing is required, which often leads to strong image distortion due to refraction among the different media. This phenomena makes the basic pinhole camera model invalid for underwater cameras, especially when using wide-angle lenses, and requires the explicit modeling of the individual optical rays. To address this problem, a ray tracing approach has been adopted to create a field-of-view (FOV) simulator for underwater cameras. The simulator allows for the testing of different housing geometries and optics for the cameras to ensure a complete hemisphere coverage in underwater operation. This paper describes the design and testing of a compact custom housing for a commercial off-the-shelf OMS camera (Ladybug 3) and presents the first results of its use. A proposed three-stage calibration process allows for the estimation of all of the relevant camera parameters. Experimental results are presented, which illustrate the performance of the calibration method and validate the approach. PMID:25774707

  13. Low Noise Camera for Suborbital Science Applications

    Science.gov (United States)

    Hyde, David; Robertson, Bryan; Holloway, Todd

    2015-01-01

    Low-cost, commercial-off-the-shelf- (COTS-) based science cameras are intended for lab use only and are not suitable for flight deployment as they are difficult to ruggedize and repackage into instruments. Also, COTS implementation may not be suitable since mission science objectives are tied to specific measurement requirements, and often require performance beyond that required by the commercial market. Custom camera development for each application is cost prohibitive for the International Space Station (ISS) or midrange science payloads due to nonrecurring expenses ($2,000 K) for ground-up camera electronics design. While each new science mission has a different suite of requirements for camera performance (detector noise, speed of image acquisition, charge-coupled device (CCD) size, operation temperature, packaging, etc.), the analog-to-digital conversion, power supply, and communications can be standardized to accommodate many different applications. The low noise camera for suborbital applications is a rugged standard camera platform that can accommodate a range of detector types and science requirements for use in inexpensive to mid range payloads supporting Earth science, solar physics, robotic vision, or astronomy experiments. Cameras developed on this platform have demonstrated the performance found in custom flight cameras at a price per camera more than an order of magnitude lower.

  14. Hairless Streaks in Cattle Implicate TSR2 in Early Hair Follicle Formation.

    Directory of Open Access Journals (Sweden)

    Leonardo Murgiano

    2015-07-01

    Full Text Available Four related cows showed hairless streaks on various parts of the body with no correlation to the pigmentation pattern. The stripes occurred in a consistent pattern resembling the lines of Blaschko. The non-syndromic hairlessness phenotype observed occurred across three generations of a single family and was compatible with an X-linked mode of inheritance. Linkage analysis and subsequent whole genome sequencing of one affected female identified two perfectly associated non-synonymous sequence variants in the critical interval on bovine chromosome X. Both variants occurred in complete linkage disequilibrium and were absent in more than 3900 controls. An ERCC6L missense mutation was predicted to cause an amino acid substitution of a non-conserved residue. Analysis in mice showed no specific Ercc6l expression pattern related to hair follicle development and therefore ERCC6L was not considered as causative gene. A point mutation at the 5'-splice junction of exon 5 of the TSR2, 20S rRNA accumulation, homolog (S. cerevisiae, gene led to the production of two mutant transcripts, both of which contain a frameshift and generate a premature stop codon predicted to truncate approximately 25% of the protein. Interestingly, in addition to the presence of both physiological TSR2 transcripts, the two mutant transcripts were predominantly detected in the hairless skin of the affected cows. Immunohistochemistry, using an antibody against the N-terminal part of the bovine protein demonstrated the specific expression of the TSR2 protein in the skin and the hair of the affected and the control cows as well as in bovine fetal skin and hair. The RNA hybridization in situ showed that Tsr2 was expressed in pre- and post-natal phases of hair follicle development in mice. Mammalian TSR2 proteins are highly conserved and are known to be broadly expressed, but their precise in vivo functions are poorly understood. Thus, by dissecting a naturally occurring mutation in a

  15. Camera self-calibration from translation by referring to a known camera.

    Science.gov (United States)

    Zhao, Bin; Hu, Zhaozheng

    2015-09-01

    This paper presents a novel linear method for camera self-calibration by referring to a known (or calibrated) camera. The method requires at least three images, with two images generated by the uncalibrated camera from pure translation and one image generated by the known reference camera. We first propose a method to compute the infinite homography from scene depths. Based on this, we use two images generated by translating the uncalibrated camera to recover scene depths, which are further utilized to linearly compute the infinite homography between an arbitrary uncalibrated image, and the image from the known camera. With the known camera as reference, the computed infinite homography is readily decomposed for camera calibration. The proposed self-calibration method has been tested with simulation and real image data. Experimental results demonstrate that the method is practical and accurate. This paper proposes using a "known reference camera" for camera calibration. The pure translation, as required in the method, is much more maneuverable, compared with some strict motions in the literature, such as pure rotation. The proposed self-calibration method has good potential for solving online camera calibration problems, which has important applications, especially for multicamera and zooming camera systems.

  16. Improving Situational Awareness in camera surveillance by combining top-view maps with camera images

    NARCIS (Netherlands)

    Kooi, F.L.; Zeeders, R.

    2009-01-01

    The goal of the experiment described is to improve today's camera surveillance in public spaces. Three designs with the camera images combined on a top-view map were compared to each other and to the current situation in camera surveillance. The goal was to test which design makes spatial

  17. Securing Embedded Smart Cameras with Trusted Computing

    Directory of Open Access Journals (Sweden)

    Winkler Thomas

    2011-01-01

    Full Text Available Camera systems are used in many applications including video surveillance for crime prevention and investigation, traffic monitoring on highways or building monitoring and automation. With the shift from analog towards digital systems, the capabilities of cameras are constantly increasing. Today's smart camera systems come with considerable computing power, large memory, and wired or wireless communication interfaces. With onboard image processing and analysis capabilities, cameras not only open new possibilities but also raise new challenges. Often overlooked are potential security issues of the camera system. The increasing amount of software running on the cameras turns them into attractive targets for attackers. Therefore, the protection of camera devices and delivered data is of critical importance. In this work we present an embedded camera prototype that uses Trusted Computing to provide security guarantees for streamed videos. With a hardware-based security solution, we ensure integrity, authenticity, and confidentiality of videos. Furthermore, we incorporate image timestamping, detection of platform reboots, and reporting of the system status. This work is not limited to theoretical considerations but also describes the implementation of a prototype system. Extensive evaluation results illustrate the practical feasibility of the approach.

  18. Using a Robotic Camera in the Classroom.

    Science.gov (United States)

    Groom, Frank M.; Bellaver, Richard

    1997-01-01

    Describes how two professors used a robotic camera to tape their classes and improve their teaching style. The camera was found to be unobtrusive and useful in providing feedback; both professors adjusted their materials and delivery approach as a result. Tapes were used in later classes and for students who missed classes. (AEF)

  19. Rosetta Star Tracker and Navigation Camera

    DEFF Research Database (Denmark)

    Thuesen, Gøsta

    1998-01-01

    Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera.......Proposal in response to the Invitation to Tender (ITT) issued by Matra Marconi Space (MSS) for the procurement of the ROSETTA Star Tracker and Navigation Camera....

  20. An Open Standard for Camera Trap Data

    Directory of Open Access Journals (Sweden)

    Tavis Forrester

    2016-12-01

    Full Text Available Camera traps that capture photos of animals are a valuable tool for monitoring biodiversity. The use of camera traps is rapidly increasing and there is an urgent need for standardization to facilitate data management, reporting and data sharing. Here we offer the Camera Trap Metadata Standard as an open data standard for storing and sharing camera trap data, developed by experts from a variety of organizations. The standard captures information necessary to share data between projects and offers a foundation for collecting the more detailed data needed for advanced analysis. The data standard captures information about study design, the type of camera used, and the location and species names for all detections in a standardized way. This information is critical for accurately assessing results from individual camera trapping projects and for combining data from multiple studies for meta-analysis. This data standard is an important step in aligning camera trapping surveys with best practices in data-intensive science. Ecology is moving rapidly into the realm of big data, and central data repositories are becoming a critical tool and are emerging for camera trap data. This data standard will help researchers standardize data terms, align past data to new repositories, and provide a framework for utilizing data across repositories and research projects to advance animal ecology and conservation.

  1. Solid State Replacement of Rotating Mirror Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Frank, A M; Bartolick, J M

    2006-08-25

    Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed ''In-situ Storage Image Sensor'' or ''ISIS'', by Prof. Goji Etoh, has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.

  2. Digital airborne camera introduction and technology

    CERN Document Server

    Sandau, Rainer

    2014-01-01

    The last decade has seen great innovations on the airborne camera. This book is the first ever written on the topic and describes all components of a digital airborne camera ranging from the object to be imaged to the mass memory device.

  3. Active spectral imaging nondestructive evaluation (SINDE) camera

    Energy Technology Data Exchange (ETDEWEB)

    Simova, E.; Rochefort, P.A., E-mail: eli.simova@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    A proof-of-concept video camera for active spectral imaging nondestructive evaluation has been demonstrated. An active multispectral imaging technique has been implemented in the visible and near infrared by using light emitting diodes with wavelengths spanning from 400 to 970 nm. This shows how the camera can be used in nondestructive evaluation to inspect surfaces and spectrally identify materials and corrosion. (author)

  4. Controlled Impact Demonstration (CID) tail camera video

    Science.gov (United States)

    1984-01-01

    The Controlled Impact Demonstration (CID) was a joint research project by NASA and the FAA to test a survivable aircraft impact using a remotely piloted Boeing 720 aircraft. The tail camera movie is one shot running 27 seconds. It shows the impact from the perspective of a camera mounted high on the vertical stabilizer, looking forward over the fuselage and wings.

  5. A Benchmark for Virtual Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    Automatically animating and placing the virtual camera in a dynamic environment is a challenging task. The camera is expected to maximise and maintain a set of properties — i.e. visual composition — while smoothly moving through the environment and avoiding obstacles. A large number of different ...

  6. Driving with head-slaved camera system

    NARCIS (Netherlands)

    Oving, A.B.; Erp, J.B.F. van

    2001-01-01

    In a field experiment, we tested the effectiveness of a head-slaved camera system for driving an armoured vehicle under armour. This system consists of a helmet-mounted display (HMD), a headtracker, and a motion platform with two cameras. Subjects performed several driving tasks on paved and in

  7. Laser Dazzling of Focal Plane Array Cameras

    NARCIS (Netherlands)

    Schleijpen, H.M.A.; Dimmeler, A.; Eberle, B; Heuvel, J.C. van den; Mieremet, A.L.; Bekman, H.H.P.T.; Mellier, B.

    2007-01-01

    Laser countermeasures against infrared focal plane array cameras aim to saturate the full camera image. In this paper we will discuss the results of dazzling experiments performed with MWIR lasers. In the “low energy” pulse regime we observe an increasing saturated area with increasing power. The

  8. Creating and Using a Camera Obscura

    Science.gov (United States)

    Quinnell, Justin

    2012-01-01

    The camera obscura (Latin for "darkened room") is the earliest optical device and goes back over 2500 years. The small pinhole or lens at the front of the room allows light to enter and this is then "projected" onto a screen inside the room. This differs from a camera, which projects its image onto light-sensitive material.…

  9. Fazendo 3d com uma camera so

    CERN Document Server

    Lunazzi, J J

    2010-01-01

    A simple system to make stereo photography or videos based in just two mirrors was made in 1989 and recently adapted to a digital camera setup. Um sistema simples para fazer fotografia ou videos em estereo baseado em dois espelhos que dividem o campo da imagem foi criado no ano 1989, e recentemente adaptado para camera digital.

  10. Cameras Monitor Spacecraft Integrity to Prevent Failures

    Science.gov (United States)

    2014-01-01

    The Jet Propulsion Laboratory contracted Malin Space Science Systems Inc. to outfit Curiosity with four of its cameras using the latest commercial imaging technology. The company parlayed the knowledge gained under working with NASA to develop an off-the-shelf line of cameras, along with a digital video recorder, designed to help troubleshoot problems that may arise on satellites in space.

  11. Incremental activity modeling in multiple disjoint cameras.

    Science.gov (United States)

    Loy, Chen Change; Xiang, Tao; Gong, Shaogang

    2012-09-01

    Activity modeling and unusual event detection in a network of cameras is challenging, particularly when the camera views are not overlapped. We show that it is possible to detect unusual events in multiple disjoint cameras as context-incoherent patterns through incremental learning of time delayed dependencies between distributed local activities observed within and across camera views. Specifically, we model multicamera activities using a Time Delayed Probabilistic Graphical Model (TD-PGM) with different nodes representing activities in different decomposed regions from different views and the directed links between nodes encoding their time delayed dependencies. To deal with visual context changes, we formulate a novel incremental learning method for modeling time delayed dependencies that change over time. We validate the effectiveness of the proposed approach using a synthetic data set and videos captured from a camera network installed at a busy underground station.

  12. Dust on Mars from MSL Engineering Cameras

    Science.gov (United States)

    Chen-Chen, Hao; Sanchez-Lavega, A.; Perez-Hoyos, Santiago

    2017-10-01

    The Mars Science Laboratory (MSL) EngineeringCameras were designed for supporting the rover surface operations. Thenavigation camera has a field of view of 45 square degrees, while the hazardavoidance camera, located at the front and rear of the rover and pointingdownwards, counts with a 124 square degrees field of view. Their imagedatabase and sky coverage provides useful information for characterising thedust aerosol physical properties at Gale Crater, complementing the dataretrieved from scientific cameras. In this work, we have reviewed andcalibrated the images from the MSL engineering cameras. The atmosphereextinction values database has been extended. Observations at low scatteringangle have been used to reproduce the dust forward scattering peak and thedust size distribution has been inferred from the sky brightness measurementsusing a discrete ordinates radiative transfer code.

  13. Stereo Cameras for Clouds (STEREOCAM) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Romps, David [Univ. of California, Berkeley, CA (United States); Oktem, Rusen [Univ. of California, Berkeley, CA (United States)

    2017-10-31

    The three pairs of stereo camera setups aim to provide synchronized and stereo calibrated time series of images that can be used for 3D cloud mask reconstruction. Each camera pair is positioned at approximately 120 degrees from the other pair, with a 17o-19o pitch angle from the ground, and at 5-6 km distance from the U.S. Department of Energy (DOE) Central Facility at the Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) observatory to cover the region from northeast, northwest, and southern views. Images from both cameras of the same stereo setup can be paired together to obtain 3D reconstruction by triangulation. 3D reconstructions from the ring of three stereo pairs can be combined together to generate a 3D mask from surrounding views. This handbook delivers all stereo reconstruction parameters of the cameras necessary to make 3D reconstructions from the stereo camera images.

  14. Lessons Learned from Crime Caught on Camera

    Science.gov (United States)

    Bernasco, Wim

    2018-01-01

    Objectives: The widespread use of camera surveillance in public places offers criminologists the opportunity to systematically and unobtrusively observe crime, their main subject matter. The purpose of this essay is to inform the reader of current developments in research on crimes caught on camera. Methods: We address the importance of direct observation of behavior and review criminological studies that used observational methods, with and without cameras, including the ones published in this issue. We also discuss the uses of camera recordings in other social sciences and in biology. Results: We formulate six key insights that emerge from the literature and make recommendations for future research. Conclusions: Camera recordings of real-life crime are likely to become part of the criminological tool kit that will help us better understand the situational and interactional elements of crime. Like any source, it has limitations that are best addressed by triangulation with other sources. PMID:29472728

  15. Gamma camera performance: technical assessment protocol

    Energy Technology Data Exchange (ETDEWEB)

    Bolster, A.A. [West Glasgow Hospitals NHS Trust, London (United Kingdom). Dept. of Clinical Physics; Waddington, W.A. [University College London Hospitals NHS Trust, London (United Kingdom). Inst. of Nuclear Medicine

    1996-12-31

    This protocol addresses the performance assessment of single and dual headed gamma cameras. No attempt is made to assess the performance of any associated computing systems. Evaluations are usually performed on a gamma camera commercially available within the United Kingdom and recently installed at a clinical site. In consultation with the manufacturer, GCAT selects the site and liaises with local staff to arrange a mutually convenient time for assessment. The manufacturer is encouraged to have a representative present during the evaluation. Three to four days are typically required for the evaluation team to perform the necessary measurements. When access time is limited, the team will modify the protocol to test the camera as thoroughly as possible. Data are acquired on the camera`s computer system and are subsequently transferred to the independent GCAT computer system for analysis. This transfer from site computer to the independent system is effected via a hardware interface and Interfile data transfer. (author).

  16. VLSI-distributed architectures for smart cameras

    Science.gov (United States)

    Wolf, Wayne H.

    2001-03-01

    Smart cameras use video/image processing algorithms to capture images as objects, not as pixels. This paper describes architectures for smart cameras that take advantage of VLSI to improve the capabilities and performance of smart camera systems. Advances in VLSI technology aid in the development of smart cameras in two ways. First, VLSI allows us to integrate large amounts of processing power and memory along with image sensors. CMOS sensors are rapidly improving in performance, allowing us to integrate sensors, logic, and memory on the same chip. As we become able to build chips with hundreds of millions of transistors, we will be able to include powerful multiprocessors on the same chip as the image sensors. We call these image sensor/multiprocessor systems image processors. Second, VLSI allows us to put a large number of these powerful sensor/processor systems on a single scene. VLSI factories will produce large quantities of these image processors, making it cost-effective to use a large number of them in a single location. Image processors will be networked into distributed cameras that use many sensors as well as the full computational resources of all the available multiprocessors. Multiple cameras make a number of image recognition tasks easier: we can select the best view of an object, eliminate occlusions, and use 3D information to improve the accuracy of object recognition. This paper outlines approaches to distributed camera design: architectures for image processors and distributed cameras; algorithms to run on distributed smart cameras, and applications of which VLSI distributed camera systems.

  17. Optimising Camera Traps for Monitoring Small Mammals

    Science.gov (United States)

    Glen, Alistair S.; Cockburn, Stuart; Nichols, Margaret; Ekanayake, Jagath; Warburton, Bruce

    2013-01-01

    Practical techniques are required to monitor invasive animals, which are often cryptic and occur at low density. Camera traps have potential for this purpose, but may have problems detecting and identifying small species. A further challenge is how to standardise the size of each camera’s field of view so capture rates are comparable between different places and times. We investigated the optimal specifications for a low-cost camera trap for small mammals. The factors tested were 1) trigger speed, 2) passive infrared vs. microwave sensor, 3) white vs. infrared flash, and 4) still photographs vs. video. We also tested a new approach to standardise each camera’s field of view. We compared the success rates of four camera trap designs in detecting and taking recognisable photographs of captive stoats (Mustelaerminea), feral cats (Felis catus) and hedgehogs (Erinaceuseuropaeus). Trigger speeds of 0.2–2.1 s captured photographs of all three target species unless the animal was running at high speed. The camera with a microwave sensor was prone to false triggers, and often failed to trigger when an animal moved in front of it. A white flash produced photographs that were more readily identified to species than those obtained under infrared light. However, a white flash may be more likely to frighten target animals, potentially affecting detection probabilities. Video footage achieved similar success rates to still cameras but required more processing time and computer memory. Placing two camera traps side by side achieved a higher success rate than using a single camera. Camera traps show considerable promise for monitoring invasive mammal control operations. Further research should address how best to standardise the size of each camera’s field of view, maximise the probability that an animal encountering a camera trap will be detected, and eliminate visible or audible cues emitted by camera traps. PMID:23840790

  18. NIR Camera/spectrograph: TEQUILA

    Science.gov (United States)

    Ruiz, E.; Sohn, E.; Cruz-Gonzalez, I.; Salas, L.; Parraga, A.; Torres, R.; Perez, M.; Cobos, F.; Tejada, C.; Iriarte, A.

    1998-11-01

    We describe the configuration and operation modes of the IR camera/spectrograph called TEQUILA, based on a 1024X1024 HgCdTe FPA (HAWAII). The optical system will allow three possible modes of operation: direct imaging, low and medium resolution spectroscopy and polarimetry. The basic system is being designed to consist of the following: 1) A LN$_2$ dewar that allocates the FPA together with the preamplifiers and a 24 filter position cylinder. 2) Control and readout electronics based on DSP modules linked to a workstation through fiber optics. 3) An optomechanical assembly cooled to -30oC that provides an efficient operation of the instrument in its various modes. 4) A control module for the moving parts of the instrument. The opto-mechanical assembly will have the necessary provisions to install a scanning Fabry-Perot interferometer and an adaptive optics correction system. The final image acquisition and control of the whole instrument is carried out in a workstation to provide the observer with a friendly environment. The system will operate at the 2.1 m telescope at the Observatorio Astronomico Nacional in San Pedro Martir, B.C. (Mexico), and is intended to be a first-light instrument for the new 7.8 m Mexican Infrared-Optical Telescope (TIM).

  19. Identification of functional sequences in the pregenomic RNA promoter of the Banana streak virus Cavendish strain (BSV-Cav).

    Science.gov (United States)

    Remans, Tony; Grof, Christopher P L; Ebert, Paul R; Schenk, Peer M

    2005-03-01

    The promoter regions of plant pararetroviruses direct transcription of the full-length viral genome into a pregenomic RNA that is an intermediate in the replication of the virus. It serves as template for reverse transcription and as polycistronic mRNA for translation to viral proteins. We have identified functional promoter elements in the intergenic region of the Cavendish isolate of Banana streak virus (BSV-Cav), a member of the genus Badnavirus. Potential binding sites for plant transcription factors were found both upstream and downstream of the transcription start site by homology search in the PLACE database of plant cis-acting elements. The functionality of these putative cis-acting elements was tested by constructing loss-of-function and "regain"-of-function mutant promoters whose activity was quantified in embryogenic sugarcane suspension cells. Four regions that are important for activity of the BSV-Cav promoter were identified: the region containing an as-1-like element, the region around -141 and down to -77, containing several putative transcription factor binding sites, the region including the CAAT-box, and the leader region. The results could help explain the high BSV-Cav promoter activity that was observed previously in transgenic sugarcane plants and give more insight into the plant cell-mediated replication of the viral genome in banana streak disease.

  20. Signal-to-noise performance analysis of streak tube imaging lidar systems. II. Theoretical analysis and discussion.

    Science.gov (United States)

    Wu, Lei; Wang, Xiaopeng; Yang, Hongru; Yu, Bing; Chen, Chao; Yang, Bin; Yuan, Liang; Wu, Lipeng; Xue, Zhanli; Li, Gaoping; Wu, Baoning

    2012-12-20

    In the preceding paper (referred to here as paper I), we presented a general signal-to-noise performance analysis of a streak tube imaging lidar (STIL) system within the framework of linear cascaded systems theory. A cascaded model is proposed for characterizing the signal-to-noise performance of a STIL system with an internal or external intensified streak tube receiver. The STIL system can be decomposed into a series of cascaded imaging chains whose signal and noise transfer properties are described by the general (or the spatial-frequency dependent) noise factors (NFs). Equations for the general NFs of the cascaded chains (or the main components) in the STIL system are derived. This work investigates the signal-to-noise performance of an external intensified STIL system. The implementation of the cascaded model for predicting and evaluating the signal-to-noise performance of the external intensified STIL system is described. Some factors that limit the signal-to-noise performance of the external intensified STIL system are analyzed and discussed.

  1. Effects of Hot Streak and Phantom Cooling on Heat Transfer in a Cooled Turbine Stage Including Particulate Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bons, Jeffrey [The Ohio State Univ., Columbus, OH (United States); Ameri, Ali [The Ohio State Univ., Columbus, OH (United States)

    2016-01-08

    The objective of this research effort was to develop a validated computational modeling capability for the characterization of the effects of hot streaks and particulate deposition on the heat load of modern gas turbines. This was accomplished with a multi-faceted approach including analytical, experimental, and computational components. A 1-year no cost extension request was approved for this effort, so the total duration was 4 years. The research effort succeeded in its ultimate objective by leveraging extensive experimental deposition studies complemented by computational modeling. Experiments were conducted with hot streaks, vane cooling, and combinations of hot streaks with vane cooling. These studies contributed to a significant body of corporate knowledge of deposition, in combination with particle rebound and deposition studies funded by other agencies, to provide suitable conditions for the development of a new model. The model includes the following physical phenomena: elastic deformation, plastic deformation, adhesion, and shear removal. It also incorporates material property sensitivity to temperature and tangential-normal velocity rebound cross-dependencies observed in experiments. The model is well-suited for incorporation in CFD simulations of complex gas turbine flows due to its algebraic (explicit) formulation. This report contains model predictions compared to coefficient of restitution data available in the open literature as well as deposition results from two different high temperature turbine deposition facilities. While the model comparisons with experiments are in many cases promising, several key aspects of particle deposition remain elusive. The simple phenomenological nature of the model allows for parametric dependencies to be evaluated in a straightforward manner. This effort also included the first-ever full turbine stage deposition model published in the open literature. The simulations included hot streaks and simulated vane cooling

  2. Keck Autoguider and Camera Server Architecture

    Science.gov (United States)

    Lupton, W. F.

    On the Keck telescope, autoguiders are not tightly integrated into the telescope control system; an autoguider is just an instrument which happens to have been asked to send guide star positions to the telescope. A standard message interface has been defined, and any source of guide star positions which adheres to this interface can play the role of the autoguider. This means that it would be easy for science instruments with fast readout rates (this of course includes all thermal infra-red instruments) to provide guide star positions. Much of an autoguider's user interface and control logic is independent of the actual source of the guide star positions. Accordingly the Keck telescope has defined an internal ``camera server'' protocol which is used by camera-independent high-level autoguider software to control physical cameras. As yet this protocol is only supported by one type of camera (the Photometrics camera which is used for all Keck autoguiders). Support for other types of camera, for example an infra-red camera, is planned. The poster display will illustrate the Keck approach to autoguiding, will show some of the advantages and disadvantages of the Keck approach, and will discuss future plans.

  3. Uav Cameras: Overview and Geometric Calibration Benchmark

    Science.gov (United States)

    Cramer, M.; Przybilla, H.-J.; Zurhorst, A.

    2017-08-01

    Different UAV platforms and sensors are used in mapping already, many of them equipped with (sometimes) modified cameras as known from the consumer market. Even though these systems normally fulfil their requested mapping accuracy, the question arises, which system performs best? This asks for a benchmark, to check selected UAV based camera systems in well-defined, reproducible environments. Such benchmark is tried within this work here. Nine different cameras used on UAV platforms, representing typical camera classes, are considered. The focus is laid on the geometry here, which is tightly linked to the process of geometrical calibration of the system. In most applications the calibration is performed in-situ, i.e. calibration parameters are obtained as part of the project data itself. This is often motivated because consumer cameras do not keep constant geometry, thus, cannot be seen as metric cameras. Still, some of the commercial systems are quite stable over time, as it was proven from repeated (terrestrial) calibrations runs. Already (pre-)calibrated systems may offer advantages, especially when the block geometry of the project does not allow for a stable and sufficient in-situ calibration. Especially for such scenario close to metric UAV cameras may have advantages. Empirical airborne test flights in a calibration field have shown how block geometry influences the estimated calibration parameters and how consistent the parameters from lab calibration can be reproduced.

  4. Towards next generation 3D cameras

    Science.gov (United States)

    Gupta, Mohit

    2017-03-01

    We are in the midst of a 3D revolution. Robots enabled by 3D cameras are beginning to autonomously drive cars, perform surgeries, and manage factories. However, when deployed in the real-world, these cameras face several challenges that prevent them from measuring 3D shape reliably. These challenges include large lighting variations (bright sunlight to dark night), presence of scattering media (fog, body tissue), and optically complex materials (metal, plastic). Due to these factors, 3D imaging is often the bottleneck in widespread adoption of several key robotics technologies. I will talk about our work on developing 3D cameras based on time-of-flight and active triangulation that addresses these long-standing problems. This includes designing `all-weather' cameras that can perform high-speed 3D scanning in harsh outdoor environments, as well as cameras that recover shape of objects with challenging material properties. These cameras are, for the first time, capable of measuring detailed (<100 microns resolution) scans in extremely demanding scenarios with low-cost components. Several of these cameras are making a practical impact in industrial automation, being adopted in robotic inspection and assembly systems.

  5. First results from the TOPSAT camera

    Science.gov (United States)

    Greenway, Paul; Tosh, Ian; Morris, Nigel; Burton, Gary; Cawley, Steve

    2017-11-01

    The TopSat camera is a low cost remote sensing imager capable of producing 2.5 metre resolution panchromatic imagery, funded by the British National Space Centre's Mosaic programme. The instrument was designed and assembled at the Space Science & Technology Department of the CCLRC's Rutherford Appleton Laboratory (RAL) in the UK, and was launched on the 27th October 2005 from Plesetsk Cosmodrome in Northern Russia on a Kosmos-3M. The camera utilises an off-axis three mirror system, which has the advantages of excellent image quality over a wide field of view, combined with a compactness that makes its overall dimensions smaller than its focal length. Keeping the costs to a minimum has been a major design driver in the development of this camera. The camera is part of the TopSat mission, which is a collaboration between four UK organisations; QinetiQ, Surrey Satellite Technology Ltd (SSTL), RAL and Infoterra. Its objective is to demonstrate provision of rapid response high resolution imagery to fixed and mobile ground stations using a low cost minisatellite. The paper "Development of the TopSat Camera" presented by RAL at the 5th ICSO in 2004 described the opto-mechanical design, assembly, alignment and environmental test methods implemented. Now that the spacecraft is in orbit and successfully acquiring images, this paper presents the first results from the camera and makes an initial assessment of the camera's in-orbit performance.

  6. Adapting virtual camera behaviour through player modelling

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    a novel approach to virtual camera control, which builds upon camera control and player modelling to provide the user with an adaptive point-of-view. To achieve this goal, we propose a methodology to model the player’s preferences on virtual camera movements and we employ the resulting models to tailor...... the viewpoint movements to the player type and her game-play style. Ultimately, the methodology is applied to a 3D platform game and is evaluated through a controlled experiment; the results suggest that the resulting adaptive cinematographic experience is favoured by some player types and it can generate...

  7. Lessons Learned from Crime Caught on Camera

    DEFF Research Database (Denmark)

    Lindegaard, Marie Rosenkrantz; Bernasco, Wim

    2018-01-01

    Objectives: The widespread use of camera surveillance in public places offers criminologists the opportunity to systematically and unobtrusively observe crime, their main subject matter. The purpose of this essay is to inform the reader of current developments in research on crimes caught on camera...... formulate six key insights that emerge from the literature and make recommendations for future research. Conclusions: Camera recordings of real-life crime are likely to become part of the criminological tool kit that will help us better understand the situational and interactional elements of crime. Like...

  8. Modelling Virtual Camera Behaviour Through Player Gaze

    DEFF Research Database (Denmark)

    Picardi, Andrea; Burelli, Paolo; Yannakakis, Georgios N.

    2012-01-01

    industry and game AI research focus on the devel- opment of increasingly sophisticated systems to automate the control of the virtual camera integrating artificial intel- ligence algorithms within physical simulations. However, in both industry and academia little research has been carried out...... on the relationship between virtual camera, game-play and player behaviour. We run a game user experiment to shed some light on this relationship and identify relevant dif- ferences between camera behaviours through different game sessions, playing behaviours and player gaze patterns. Re- sults show that users can...

  9. A Dataset for Camera Independent Color Constancy.

    Science.gov (United States)

    Aytekin, Caglar; Nikkanen, Jarno; Gabbouj, Moncef

    2017-10-17

    In this paper, we provide a novel dataset designed for camera independent color constancy research. Camera independence corresponds to the robustness of an algorithm's performance when run on images of the same scene taken by different cameras. Accordingly, the images in our database correspond to several lab and field scenes each of which is captured by three different cameras with minimal registration errors. The lab scenes are also captured under five different illuminations. The spectral responses of cameras and the spectral power distributions of the lab light sources are also provided, as they may prove beneficial for training future algorithms to achieve color constancy. For a fair evaluation of future methods, we provide guidelines for supervised methods with indicated training, validation and testing partitions. Accordingly, we evaluate two recently proposed convolutional neural network based color constancy algorithms as baselines for future research. As a side contribution, this dataset also includes images taken by a mobile camera with color shading corrected and uncorrected results. This allows research on the effect of color shading as well.In this paper, we provide a novel dataset designed for camera independent color constancy research. Camera independence corresponds to the robustness of an algorithm's performance when run on images of the same scene taken by different cameras. Accordingly, the images in our database correspond to several lab and field scenes each of which is captured by three different cameras with minimal registration errors. The lab scenes are also captured under five different illuminations. The spectral responses of cameras and the spectral power distributions of the lab light sources are also provided, as they may prove beneficial for training future algorithms to achieve color constancy. For a fair evaluation of future methods, we provide guidelines for supervised methods with indicated training, validation and testing

  10. Morphology of the Venus clouds from the imaging by Venus Monitoring Camera onboard Venus Express

    Science.gov (United States)

    Titov, D. V.; Markiewicz, W. J.; Moissl, R.; Ignatiev, N.; Limaye, S.; Khatuntsev, I.; Roatsch, Th.; Almeida, M.

    2008-09-01

    For more than 2 years Venus Monitoring Camera onboard ESA's Venus Express collects images of Venus from global views with resolution of ~50 km to close-up snapshots resolving features of about few hundreds meters. The UV filter is centered at a characteristic wavelength of the unknown UV absorber (365 nm) and allows one to study morphology of the cloud tops that bears the information about dynamical process and distribution of the UV absorber. Low latitudes (polar hood sometimes crossed by dark thin (~300 km) spiral or circular structures. This global cloud pattern changes on time scales of few days resulting in so called "brightening events" when the bright haze can extend far into low latitudes. Cloud pattern shows remarkable diurnal variability. Afternoon sector of the planet has strongly developed traces of turbulence in contrast to the atmosphere in the morning. Also the bright hood extends further to low latitudes in the morning than in the evening. We will present latitudinal, diurnal, and temporal variations based on two years of VMC observations. Imaging of streaky clouds in the middle and high latitudes provides a tool to study the wind pattern. We will also present preliminary results on the cloud streaks orientation derived from the VMC images.

  11. Camera Based Navigation System with Augmented Reality

    Directory of Open Access Journals (Sweden)

    M. Marcu

    2012-06-01

    Full Text Available Nowadays smart mobile devices have enough processing power, memory, storage and always connected wireless communication bandwidth that makes them available for any type of application. Augmented reality (AR proposes a new type of applications that tries to enhance the real world by superimposing or combining virtual objects or computer generated information with it. In this paper we present a camera based navigation system with augmented reality integration. The proposed system aims to the following: the user points the camera of the smartphone towards a point of interest, like a building or any other place, and the application searches for relevant information about that specific place and superimposes the data over the video feed on the display. When the user moves the camera away, changing its orientation, the data changes as well, in real-time, with the proper information about the place that is now in the camera view.

  12. CALIBRATION PROCEDURES ON OBLIQUE CAMERA SETUPS

    Directory of Open Access Journals (Sweden)

    G. Kemper

    2016-06-01

    Full Text Available Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. The shown sensor (Oblique Imager is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna –IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first

  13. Calibration Procedures on Oblique Camera Setups

    Science.gov (United States)

    Kemper, G.; Melykuti, B.; Yu, C.

    2016-06-01

    Beside the creation of virtual animated 3D City models, analysis for homeland security and city planning, the accurately determination of geometric features out of oblique imagery is an important task today. Due to the huge number of single images the reduction of control points force to make use of direct referencing devices. This causes a precise camera-calibration and additional adjustment procedures. This paper aims to show the workflow of the various calibration steps and will present examples of the calibration flight with the final 3D City model. In difference to most other software, the oblique cameras are used not as co-registered sensors in relation to the nadir one, all camera images enter the AT process as single pre-oriented data. This enables a better post calibration in order to detect variations in the single camera calibration and other mechanical effects. The shown sensor (Oblique Imager) is based o 5 Phase One cameras were the nadir one has 80 MPIX equipped with a 50 mm lens while the oblique ones capture images with 50 MPix using 80 mm lenses. The cameras are mounted robust inside a housing to protect this against physical and thermal deformations. The sensor head hosts also an IMU which is connected to a POS AV GNSS Receiver. The sensor is stabilized by a gyro-mount which creates floating Antenna -IMU lever arms. They had to be registered together with the Raw GNSS-IMU Data. The camera calibration procedure was performed based on a special calibration flight with 351 shoots of all 5 cameras and registered the GPS/IMU data. This specific mission was designed in two different altitudes with additional cross lines on each flying heights. The five images from each exposure positions have no overlaps but in the block there are many overlaps resulting in up to 200 measurements per points. On each photo there were in average 110 well distributed measured points which is a satisfying number for the camera calibration. In a first step with the help of

  14. POLICE BODY CAMERAS: SEEING MAY BE BELIEVING

    Directory of Open Access Journals (Sweden)

    Noel Otu

    2016-11-01

    Full Text Available While the concept of body-mounted cameras (BMC worn by police officers is a controversial issue, it is not new. Since in the early-2000s, police departments across the United States, England, Brazil, and Australia have been implementing wearable cameras. Like all devices used in policing, body-mounted cameras can create a sense of increased power, but also additional responsibilities for both the agencies and individual officers. This paper examines the public debate regarding body-mounted cameras. The conclusions drawn show that while these devices can provide information about incidents relating to police–citizen encounters, and can deter citizen and police misbehavior, these devices can also violate a citizen’s privacy rights. This paper outlines several ramifications for practice as well as implications for policy.

  15. Ge Quantum Dot Infrared Imaging Camera Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Luna Innovations Incorporated proposes to develop a high performance Ge quantum dots-based infrared (IR) imaging camera on Si substrate. The high sensitivity, large...

  16. Camera vibration measurement using blinking light-emitting diode array.

    Science.gov (United States)

    Nishi, Kazuki; Matsuda, Yuichi

    2017-01-23

    We present a new method for measuring camera vibrations such as camera shake and shutter shock. This method successfully detects the vibration trajectory and transient waveforms from the camera image itself. We employ a time-varying pattern as the camera test chart over the conventional static pattern. This pattern is implemented using a specially developed blinking light-emitting-diode array. We describe the theoretical framework and pattern analysis of the camera image for measuring camera vibrations. Our verification experiments show that our method has a detection accuracy and sensitivity of 0.1 pixels, and is robust against image distortion. Measurement results of camera vibrations in commercial cameras are also demonstrated.

  17. Comparative analysis of virus-derived small RNAs within cassava (Manihot esculenta Crantz) infected with cassava brown streak viruses.

    Science.gov (United States)

    Ogwok, Emmanuel; Ilyas, Muhammad; Alicai, Titus; Rey, Marie E C; Taylor, Nigel J

    2016-04-02

    Infection of plant cells by viral pathogens triggers RNA silencing, an innate antiviral defense mechanism. In response to infection, small RNAs (sRNAs) are produced that associate with Argonaute (AGO)-containing silencing complexes which act to inactivate viral genomes by posttranscriptional gene silencing (PTGS). Deep sequencing was used to compare virus-derived small RNAs (vsRNAs) in cassava genotypes NASE 3, TME 204 and 60444 infected with the positive sense single-stranded RNA (+ssRNA) viruses cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV), the causal agents of cassava brown streak disease (CBSD). An abundance of 21-24nt vsRNAs was detected and mapped, covering the entire CBSV and UCBSV genomes. The 21nt vsRNAs were most predominant, followed by the 22 nt class with a slight bias toward sense compared to antisense polarity, and a bias for adenine and uracil bases present at the 5'-terminus. Distribution and frequency of vsRNAs differed between cassava genotypes and viral genomes. In susceptible genotypes TME 204 and 60444, CBSV-derived sRNAs were seen in greater abundance than UCBSV-derived sRNAs. NASE 3, known to be resistant to UCBSV, accumulated negligible UCBSV-derived sRNAs but high populations of CBSV-derived sRNAs. Transcript levels of cassava homologues of AGO2, DCL2 and DCL4, which are central to the gene-silencing complex, were found to be differentially regulated in CBSV- and UCBSV-infected plants across genotypes, suggesting these proteins play a role in antiviral defense. Irrespective of genotype or viral pathogen, maximum populations of vsRNAs mapped to the cytoplasmic inclusion, P1 and P3 protein-encoding regions. Our results indicate disparity between CBSV and UCBSV host-virus interaction mechanisms, and provide insight into the role of virus-induced gene silencing as a mechanism of resistance to CBSD. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. A stereoscopic lens for digital cinema cameras

    Science.gov (United States)

    Lipton, Lenny; Rupkalvis, John

    2015-03-01

    Live-action stereoscopic feature films are, for the most part, produced using a costly post-production process to convert planar cinematography into stereo-pair images and are only occasionally shot stereoscopically using bulky dual-cameras that are adaptations of the Ramsdell rig. The stereoscopic lens design described here might very well encourage more live-action image capture because it uses standard digital cinema cameras and workflow to save time and money.

  19. MCP gated x-ray framing camera

    Science.gov (United States)

    Cai, Houzhi; Liu, Jinyuan; Niu, Lihong; Liao, Hua; Zhou, Junlan

    2009-11-01

    A four-frame gated microchannel plate (MCP) camera is described in this article. Each frame photocathode coated with gold on the MCP is part of a transmission line with open circuit end driven by the gating electrical pulse. The gating pulse is 230 ps in width and 2.5 kV in amplitude. The camera is tested by illuminating its photocathode with ultraviolet laser pulses, 266 nm in wavelength, which shows exposure time as short as 80 ps.

  20. Face identification in videos from mobile cameras

    OpenAIRE

    Mu, Meiru; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2014-01-01

    It is still challenging to recognize faces reliably in videos from mobile camera, although mature automatic face recognition technology for still images has been available for quite some time. Suppose we want to be alerted when suspects appear in the recording of a police Body-Cam, even a good face matcher on still images would give many false alarms due to the uncontrolled conditions. This paper presents an approach to identify faces in videos from mobile cameras. A commercial face matcher F...

  1. The Use of Camera Traps in Wildlife

    Directory of Open Access Journals (Sweden)

    Yasin Uçarlı

    2013-11-01

    Full Text Available Camera traps are increasingly used in the abundance and density estimates of wildlife species. Camera traps are very good alternative for direct observation in case, particularly, steep terrain, dense vegetation covered areas or nocturnal species. The main reason for the use of camera traps is eliminated that the economic, personnel and time loss in a continuous manner at the same time in different points. Camera traps, motion and heat sensitive, can take a photo or video according to the models. Crossover points and feeding or mating areas of the focal species are addressed as a priority camera trap set locations. The population size can be finding out by the images combined with Capture-Recapture methods. The population density came out the population size divided to effective sampling area size. Mating and breeding season, habitat choice, group structures and survival rates of the focal species can be achieved from the images. Camera traps are very useful to obtain the necessary data about the particularly mysterious species with economically in planning and conservation efforts.

  2. Minimum Requirements for Taxicab Security Cameras*

    Science.gov (United States)

    Zeng, Shengke; Amandus, Harlan E.; Amendola, Alfred A.; Newbraugh, Bradley H.; Cantis, Douglas M.; Weaver, Darlene

    2015-01-01

    Problem The homicide rate of taxicab-industry is 20 times greater than that of all workers. A NIOSH study showed that cities with taxicab-security cameras experienced significant reduction in taxicab driver homicides. Methods Minimum technical requirements and a standard test protocol for taxicab-security cameras for effective taxicab-facial identification were determined. The study took more than 10,000 photographs of human-face charts in a simulated-taxicab with various photographic resolutions, dynamic ranges, lens-distortions, and motion-blurs in various light and cab-seat conditions. Thirteen volunteer photograph-evaluators evaluated these face photographs and voted for the minimum technical requirements for taxicab-security cameras. Results Five worst-case scenario photographic image quality thresholds were suggested: the resolution of XGA-format, highlight-dynamic-range of 1 EV, twilight-dynamic-range of 3.3 EV, lens-distortion of 30%, and shutter-speed of 1/30 second. Practical Applications These minimum requirements will help taxicab regulators and fleets to identify effective taxicab-security cameras, and help taxicab-security camera manufacturers to improve the camera facial identification capability. PMID:26823992

  3. Low light performance of digital still cameras

    Science.gov (United States)

    Wueller, Dietmar

    2013-03-01

    The major difference between a dSLR camera, a consumer camera, and a camera in a mobile device is the sensor size. The sensor size is also related to the over all system size including the lens. With the sensors getting smaller the individual light sensitive areas are also getting smaller leaving less light falling onto each of the pixels. This effect requires higher signal amplification that leads to higher noise levels or other problems that may occur due to denoising algorithms. These Problems become more visible at low light conditions because of the lower signal levels. The fact that the sensitivity of cameras decreases makes customers ask for a standardized way to measure low light performance of cameras. The CEA (Consumer Electronics Association) together with ANSI has addressed this for camcorders in the CEA-639 [1] standard. The ISO technical committee 42 (photography) is currently also thinking about a potential standard on this topic for still picture cameras. This paper is part of the preparation work for this standardization activity and addresses the differences compared to camcorders and also potential additional problems with noise reduction that have occurred over the past few years. The result of this paper is a proposed test procedure with a few open questions that have to be answered in future work.

  4. Multi-Angle Snowflake Camera Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Stuefer, Martin [Univ. of Alaska, Fairbanks, AK (United States); Bailey, J. [Univ. of Alaska, Fairbanks, AK (United States)

    2016-07-01

    The Multi-Angle Snowflake Camera (MASC) takes 9- to 37-micron resolution stereographic photographs of free-falling hydrometers from three angles, while simultaneously measuring their fall speed. Information about hydrometeor size, shape orientation, and aspect ratio is derived from MASC photographs. The instrument consists of three commercial cameras separated by angles of 36º. Each camera field of view is aligned to have a common single focus point about 10 cm distant from the cameras. Two near-infrared emitter pairs are aligned with the camera’s field of view within a 10-angular ring and detect hydrometeor passage, with the lower emitters configured to trigger the MASC cameras. The sensitive IR motion sensors are designed to filter out slow variations in ambient light. Fall speed is derived from successive triggers along the fall path. The camera exposure times are extremely short, in the range of 1/25,000th of a second, enabling the MASC to capture snowflake sizes ranging from 30 micrometers to 3 cm.

  5. A constellation of SmallSats with synthetic tracking cameras to search for 90% of potentially hazardous near-Earth objects

    Science.gov (United States)

    Shao, Michael; Turyshev, Slava G.; Spangelo, Sara; Werne, Thomas; Zhai, Chengxing

    2017-07-01

    We present a new space mission concept that is capable of finding, detecting, and tracking 90% of near-Earth objects (NEO) with H magnitude of H ≤ 22 (i.e., 140 m in size) that are potentially hazardous to the Earth. The new mission concept relies on two emerging technologies: the technique of synthetic tracking and the new generation of small and capable interplanetary spacecraft. Synthetic tracking is a technique that de-streaks asteroid images by taking multiple fast exposures. With synthetic tracking, an 800 s observation with a 10 cm telescope in space can detect a moving object with apparent magnitude of 20.5 without losing sensitivity from streaking. We refer to NEOs with a minimum orbit intersection distance of constellation of six SmallSats (comparable in size to 9U CubeSats) equipped with 10 cm synthetic tracking cameras and evenly-distributed in 1.0 au heliocentric orbit could detect 90% of EGs with H ≤ 22 mag in 3.8 yr of observing time. A more advanced constellation of nine 20 cm telescopes could detect 90% of H = 24.2 mag (i.e., 50 m in size) EGs in less than 5 yr.

  6. Variable Number of Tandem Repeat Markers in the Genome Sequence of Mycosphaerella Fijiensis, the Causal Agent of Black Leaf Streak Disease of Banana (Musa spp.)

    Science.gov (United States)

    Mycosphaerella fijiensis, the causal agent of banana leaf streak disease (commonly known as black Sigatoka), is the most devastating pathogen attacking bananas (Musa spp). Recently the whole genome sequence of M. fijiensis became available. This sequence was screened for the presence of Variable Num...

  7. Molecular interactions and immune responses between maize fine streak virus and the leafhopper vector G. nigrifrons through differential expression and RNA interference

    Science.gov (United States)

    Maize fine streak virus (MFSV) is an emerging virus of maize that is transmitted by an insect vector, the leafhopper called Graminella nigrifrons. Virus transmission by the leafhopper requires that the virus enter into and multiply in insect cells, tissues and organs before being transmitted to a ne...

  8. Particle streak velocimetry-OCT (PSV-OCT): a novel method for multi-vector component velocimetry of microscale flow physiology (Conference Presentation)

    Science.gov (United States)

    Zhou, Kevin C.; Huang, Brendan K.; Gamm, Ute A.; Bhandari, Vineet; Khokha, Mustafa K.; Choma, Michael A.

    2016-03-01

    We present a new method for 2.5 and 3 vector component velocimetry. We call this method particle streak velocimetry OCT (PSV-OCT). PSV-OCT generates two-dimensional, 2.5 vector component (v_x,|v_y|,v_z) cross-sectional maps of microscale flow velocity (e.g. biological cilia-driven fluid flow). The enabling insight is that a tracer particle in sparsely-seeded fluid flow traces out streaks in (x,z,t)-space. The streak orientations in x-t and z-t yield v_x and v_z, respectively. The in-plane (x-z plane) residence time yields the out-of-plane speed |v_y|. Vector component values are generated by fitting streaks to a model of image formation. We demonstrate cross-sectional estimation of (v_x,|v_y|,v_z) in two important animal models in ciliary biology: Xenopus embryos (tadpoles) and mouse trachea. Further, by incorporation the assumption of incompressible flow into the estimation process, we are able to generate 3 vector component (v_x,v_y,v_z) estimates in three spatial dimensions from 2.5 vector component measurements taken in parallel OCT planes in 3D space.

  9. Optimal streaks in the wake of a blunt-based axisymmetric bluff body and their influence on vortex shedding

    Science.gov (United States)

    Marant, Mathieu; Cossu, Carlo; Pujals, Grégory

    2017-06-01

    We compute the optimal perturbations of azimuthal wavenumber m THAT maximize the spatial energy growth in the wake of a blunt-based axisymmetric bluff body. Optimal perturbations with m ≠ 0 lead to the amplification of streamwise streaks in the wake. When forced with finite amplitude m ≠ 1, optimal perturbations have a stabilizing effect on large-scale unsteady vortex shedding in the wake. We show that m ≥ 2 modes, which are forced with zero mass flux, can significantly reduce the amplitude of the unsteady lift force exerted on the body. When combined with low levels of base bleed, these perturbations can completely suppress the unsteadiness in the wake with reduced levels of mass injection in the flow.

  10. Jet streak circulations associated with a moderate snowfall event as diagnosed from NGM model output. [Nested Grid Model

    Science.gov (United States)

    Kocin, Paul J.; Uccellini, Louis W.; Skillman, William C.; Grumm, Richard H.

    1989-01-01

    The existence, evolution, and interaction of vertical circulations associated with upper-level jet streaks during a moderate snowfall event are diagnosed using a nested grid model (NGM). The event itself is overviewed, and the diagnosis of transverse circulations utilizing NGM output is discussed. Focus is placed on the identification of the horizontal and vertical components of the circulation, the temporal evolution of the circulation, and the comparison of the circulation from successive model forecasts. A preliminary analysis of the model data indicates that the horizontal and vertical branches of the circulations can be diagnosed from the model output, and the horizontal and vertical components of the circulations may be identified and followed during an individual forecast cycle.

  11. A point-by-point analysis of performance in a fencing match: psychological processes associated with winning and losing streaks.

    Science.gov (United States)

    Doron, Julie; Gaudreau, Patrick

    2014-02-01

    This study aimed to revisit the complex nature of serial dependency of performance during a match, examining the prospective associations between psychological processes and subsequent performance at the within-person level of analysis, and explore whether psychological processes are associated with the likelihood of winning series of points. A process-oriented sequential approach was used with 16 elite fencers during a simulated competition. Multilevel regression analyses revealed that serial dependency of performance fluctuates within a match. Results of a Bayesian multilevel structural equation model showed that prior performance subsequently influenced psychological processes. Although psychological processes did not predict performance in the subsequent point, successive winnings were associated with higher perceived control and task-oriented coping and lower negative affectivity compared with both losing streaks and nonstreaks. Overall, serial dependencies of performance are nonstationary during a match whereas psychological processes significantly differ in episodes of winning after winning versus losing after losing.

  12. CALIBRATION PROCEDURES IN MID FORMAT CAMERA SETUPS

    Directory of Open Access Journals (Sweden)

    F. Pivnicka

    2012-07-01

    Full Text Available A growing number of mid-format cameras are used for aerial surveying projects. To achieve a reliable and geometrically precise result also in the photogrammetric workflow, awareness on the sensitive parts is important. The use of direct referencing systems (GPS/IMU, the mounting on a stabilizing camera platform and the specific values of the mid format camera make a professional setup with various calibration and misalignment operations necessary. An important part is to have a proper camera calibration. Using aerial images over a well designed test field with 3D structures and/or different flight altitudes enable the determination of calibration values in Bingo software. It will be demonstrated how such a calibration can be performed. The direct referencing device must be mounted in a solid and reliable way to the camera. Beside the mechanical work especially in mounting the camera beside the IMU, 2 lever arms have to be measured in mm accuracy. Important are the lever arms from the GPS Antenna to the IMU's calibrated centre and also the lever arm from the IMU centre to the Camera projection centre. In fact, the measurement with a total station is not a difficult task but the definition of the right centres and the need for using rotation matrices can cause serious accuracy problems. The benefit of small and medium format cameras is that also smaller aircrafts can be used. Like that, a gyro bases stabilized platform is recommended. This causes, that the IMU must be mounted beside the camera on the stabilizer. The advantage is, that the IMU can be used to control the platform, the problematic thing is, that the IMU to GPS antenna lever arm is floating. In fact we have to deal with an additional data stream, the values of the movement of the stabiliser to correct the floating lever arm distances. If the post-processing of the GPS-IMU data by taking the floating levers into account, delivers an expected result, the lever arms between IMU and

  13. Terpene Profile, Leaf Anatomy, and Enzyme Activity of Resistant and Susceptible Cocoa Clonesto Vascular Streak Dieback Disease

    Directory of Open Access Journals (Sweden)

    Adi Prawoto

    2014-10-01

    Full Text Available Vascular-streak dieback (VSD, Oncobasidium theobromae is the most prevalent disease of Theobroma cacao L. in Indonesia. This study aims to analyze resistance mechanism to VSD based on terpene profile, leaf anatomy, chitinase, and peroxidase study. Resistant clones of Sulawesi 1 and Sca 6 and susceptible clones of ICS 60 and TSH 858 were used for terpene profile, leaf anatomy analysis, chitinase, peroxides, polyphenol, lignin, and cellulose analysis. Those clones and KEE 2, KKM 22 and ICS 13 were used for peroxides analysis. For trichome study, the resistant clones of Sulawesi 1, Sca 6, KEE 2, and KKM 22, and susceptible clones of ICS 60 and TSH 858 were used. GCMS analysis showed that chromatogram pattern of resistant and susceptible groups were quite similar, but resistant clones contained 22% more components than the susceptible ones. Resistant clones contained groups of pinene, decane, myrcene, and octadecanoic acid, while those substances on usceptible clones were absent. Trichome was thicker on younger leaf, and its density on the basal was higher than that on the middle and tip leaf parts. Trichome density of resistant clone was not always thicker than that of susceptible ones. On resistant clones, stomatal density was lower and width of stomate pits was narrower, while thickness of epidermis layer and pallisade parenchym were higher. Polyphenol content of resistant clones were higher but lignin and cellulose of both groups were similar. Chitinase activity which has a role in hydrolysis of mycelia cell wall was higher on the resistant clones, but peroxides which has a role in polymeration of lignin biosynthesis was similar between both groups. It is concluded that groups of terpene pinene, decane, myrcene, and octadecanoic acid, thickness of leaf epidermis, density and width of stomata pit, and chitinase activity plays important role in cocoa resistance to VSD. Key words: Theobroma cacaoL., clone, vascular-streak dieback, resistance, leaf

  14. Southern rice black-streaked dwarf virus: a white-backed planthopper-transmitted fijivirus threatening rice production in Asia

    Science.gov (United States)

    Zhou, Guohui; Xu, Donglin; Xu, Dagao; Zhang, Maoxin

    2013-01-01

    Southern rice black-streaked dwarf virus (SRBSDV), a non-enveloped icosahedral virus with a genome of 10 double-stranded RNA segments, is a novel species in the genus Fijivirus (family Reoviridae) first recognized in 2008. Rice plants infected with this virus exhibit symptoms similar to those caused by Rice black-streaked dwarf virus. Since 2009, the virus has rapidly spread and caused serious rice losses in East and Southeast Asia. Significant progress has been made in recent years in understanding this disease, especially about the functions of the viral genes, rice–virus–insect interactions, and epidemiology and control measures. The virus can be efficiently transmitted by the white-backed planthopper (WBPH, Sogatella furcifera) in a persistent circulative propagative manner but cannot be transmitted by the brown planthopper (Nilaparvata lugens) and small brown planthopper (Laodelphax striatellus). Rice, maize, Chinese sorghum (Coix lacryma-jobi) and other grass weeds can be infected via WBPH. However, only rice plays a major role in the virus infection cycle because of the vector’s preference. In Southeast Asia, WBPH is a long-distance migratory rice pest. The disease cycle can be described as follows: SRBSDV and its WBPH vector overwinter in warm tropical or sub-tropical areas; viruliferous WBPH adults carry the virus from south to north via long-distance migration in early spring, transmit the virus to rice seedlings in the newly colonized areas, and lay eggs on the infected seedlings; the next generation of WBPHs propagate on infected seedlings, become viruliferous, disperse, and cause new disease outbreaks. Several molecular and serological methods have been developed to detect SRBSDV in plant tissues and individual insects. Control measures based on protection from WBPH, including seedbed coverage, chemical seed treatments, and chemical spraying of seedlings, have proven effective in China. PMID:24058362

  15. Southern rice black-streaked dwarf virus: a white-backed planthopper transmitted fijivirus threadening rice production in Asia

    Directory of Open Access Journals (Sweden)

    Guohui eZhou

    2013-09-01

    Full Text Available Southern rice black-streaked dwarf virus (SRBSDV, a nonenveloped icosahedral virus with a genome of 10 double-stranded RNA segments, is a novel species in the genus Fijivirus (family Reoviridae first recognized in 2008. Rice plants infected with this virus exhibit symptoms similar to those caused by Rice black-streaked dwarf virus. Since 2009, the virus has rapidly spread and caused serious rice losses in East and Southeast Asia. Significant progress has been made in recent years in understanding this disease, especially about the functions of the viral genes, rice–virus–insect interactions, and epidemiology and control measures. The virus can be efficiently transmitted by the white-backed planthopper (WBPH, Sogatella furcifera in a persistent circulative propagative manner but cannot be transmitted by the brown planthopper (Nilaparvata lugens and small brown planthopper (Laodelphax striatellus. Rice, maize, Chinese sorghum (Coix lacryma-jobi and other grass weeds can be infected via WBPH. However, only rice plays a major role in the virus infection cycle because of the vector's preference. In Southeast Asia, WBPH is a long-distance migratory rice pest. The disease cycle can be described as follows: SRBSDV and its WBPH vector overwinter in warm tropical or sub-tropical areas; viruliferous WBPH adults carry the virus from south to north via long-distance migration in early spring, transmit the virus to rice seedlings in the newly colonized areas, and lay eggs on the infected seedlings; the next generation of WBPHs propagate on infected seedlings, become viruliferous, disperse, and cause new disease outbreaks. Several molecular and serological methods have been developed to detect SRBSDV in plant tissues and individual insects. Control measures based on protection from WBPH, including seedbed coverage, chemical seed treatments, and chemical spraying of seedlings, have proven effective in China.

  16. Southern rice black-streaked dwarf virus: a white-backed planthopper-transmitted fijivirus threatening rice production in Asia.

    Science.gov (United States)

    Zhou, Guohui; Xu, Donglin; Xu, Dagao; Zhang, Maoxin

    2013-09-09

    Southern rice black-streaked dwarf virus (SRBSDV), a non-enveloped icosahedral virus with a genome of 10 double-stranded RNA segments, is a novel species in the genus Fijivirus (family Reoviridae) first recognized in 2008. Rice plants infected with this virus exhibit symptoms similar to those caused by Rice black-streaked dwarf virus. Since 2009, the virus has rapidly spread and caused serious rice losses in East and Southeast Asia. Significant progress has been made in recent years in understanding this disease, especially about the functions of the viral genes, rice-virus-insect interactions, and epidemiology and control measures. The virus can be efficiently transmitted by the white-backed planthopper (WBPH, Sogatella furcifera) in a persistent circulative propagative manner but cannot be transmitted by the brown planthopper (Nilaparvata lugens) and small brown planthopper (Laodelphax striatellus). Rice, maize, Chinese sorghum (Coix lacryma-jobi) and other grass weeds can be infected via WBPH. However, only rice plays a major role in the virus infection cycle because of the vector's preference. In Southeast Asia, WBPH is a long-distance migratory rice pest. The disease cycle can be described as follows: SRBSDV and its WBPH vector overwinter in warm tropical or sub-tropical areas; viruliferous WBPH adults carry the virus from south to north via long-distance migration in early spring, transmit the virus to rice seedlings in the newly colonized areas, and lay eggs on the infected seedlings; the next generation of WBPHs propagate on infected seedlings, become viruliferous, disperse, and cause new disease outbreaks. Several molecular and serological methods have been developed to detect SRBSDV in plant tissues and individual insects. Control measures based on protection from WBPH, including seedbed coverage, chemical seed treatments, and chemical spraying of seedlings, have proven effective in China.

  17. New developments to improve SO2 cameras

    Science.gov (United States)

    Luebcke, P.; Bobrowski, N.; Hoermann, C.; Kern, C.; Klein, A.; Kuhn, J.; Vogel, L.; Platt, U.

    2012-12-01

    The SO2 camera is a remote sensing instrument that measures the two-dimensional distribution of SO2 (column densities) in volcanic plumes using scattered solar radiation as a light source. From these data SO2-fluxes can be derived. The high time resolution of the order of 1 Hz allows correlating SO2 flux measurements with other traditional volcanological measurement techniques, i.e., seismology. In the last years the application of SO2 cameras has increased, however, there is still potential to improve the instrumentation. First of all, the influence of aerosols and ash in the volcanic plume can lead to large errors in the calculated SO2 flux, if not accounted for. We present two different concepts to deal with the influence of ash and aerosols. The first approach uses a co-axial DOAS system that was added to a two filter SO2 camera. The camera used Filter A (peak transmission centred around 315 nm) to measures the optical density of SO2 and Filter B (centred around 330 nm) to correct for the influence of ash and aerosol. The DOAS system simultaneously performs spectroscopic measurements in a small area of the camera's field of view and gives additional information to correct for these effects. Comparing the optical densities for the two filters with the SO2 column density from the DOAS allows not only a much more precise calibration, but also to draw conclusions about the influence from ash and aerosol scattering. Measurement examples from Popocatépetl, Mexico in 2011 are shown and interpreted. Another approach combines the SO2 camera measurement principle with the extremely narrow and periodic transmission of a Fabry-Pérot interferometer. The narrow transmission window allows to select individual SO2 absorption bands (or series of bands) as a substitute for Filter A. Measurements are therefore more selective to SO2. Instead of Filter B, as in classical SO2 cameras, the correction for aerosol can be performed by shifting the transmission window of the Fabry

  18. The calibration of read-out-streak photometry in the XMM-Newton Optical Monitor and the construction of a bright-source catalogue

    Science.gov (United States)

    Page, M. J.; Chan, N.; Breeveld, A. A.; Talavera, A.; Yershov, V.; Kennedy, T.; Kuin, N. P. M.; Hancock, B.; Smith, P. J.; Carter, M.

    2017-04-01

    The dynamic range of the XMM-Newton Optical Monitor (XMM-OM) is limited at the bright end by coincidence loss, the superposition of multiple photons in the individual frames recorded from its micro-channel-plate (MCP) intensified charge-coupled device (CCD) detector. One way to overcome this limitation is to use photons that arrive during the frame transfer of the CCD, forming vertical read-out streaks for bright sources. We calibrate these read-out streaks for photometry of bright sources observed with XMM-OM. The bright-source limit for read-out-streak photometry is set by the recharge time of the MCPs. For XMM-OM, we find that the MCP recharge time is 5.5 × 10-4 s. We determine that the effective bright limits for read-out-streak photometry with XMM-OM are approximately 1.5 mag brighter than the bright-source limits for normal aperture photometry in full-frame images. This translates into bright-source limits in Vega magnitudes of UVW2=7.1, UVM2=8.0, UVW1=9.4, U=10.5, B=11.5, V=10.2, and White=12.5 for data taken early in the mission. The limits brighten by up to 0.2 mag, depending on filter, over the course of the mission as the detector ages. The method is demonstrated by deriving UVW1 photometry for the symbiotic nova RR Telescopii, and the new photometry is used to constrain the e-folding time of its decaying ultraviolet (UV) emission. Using the read-out-streak method, we obtain photometry for 50 per cent of the missing UV source measurements in version 2.1 of the XMM-Newton Serendipitous UV Source Survey catalogue.

  19. Dental shade matching using a digital camera.

    Science.gov (United States)

    Tam, W K; Lee, H J

    2012-12-01

    Digital cameras could be substitutes for contact-type instruments in shade selection and overcome their drawbacks. The images taken show morphology and color texture of teeth. A new method was proposed to compare the color of shade tabs taken by a digital camera using appropriate color features. Vita 3D-MASTER shade guide and Canon EOS 1100D digital camera were employed. Shade tab images were compared in two reference strategies. The color of tooth surface was presented by a content manually cropped out of the image. The content was divided into 10 × 2 blocks to encode the color distribution. Color features from commonly used color spaces were evaluated. The top n matches were selected when the least n shade distances between the shade tabs were attained. Using Sa*b* features, the top one accuracy was 0.87, where the feature S is defined in HSV color space, a* and b* features are defined in L*a*b* color space. This rate was higher than previous reports using contact-type instruments. The top three matching accuracy was 0.94. Sa*b* were suitable features for shade matching using a digital cameras in this study. Both the color and texture of the tooth surface could be presented by the proposed content-based descriptor. Clinical use of digital cameras in shade matching became possible. This in vitro study proposed a method for shade matching using digital cameras through the comparisons of the color patterns on the shade tab surfaces. The method overcame some drawbacks from the devices such as colorimeters or spectrophotometers. The results supported the use of digital cameras in shade matching. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. How to Build Your Own Document Camera for around $100

    Science.gov (United States)

    Van Orden, Stephen

    2010-01-01

    Document cameras can have great utility in second language classrooms. However, entry-level consumer document cameras start at around $350. This article describes how the author built three document cameras and offers suggestions for how teachers can successfully build their own quality document camera using a webcam for around $100.

  1. 16 CFR 1025.45 - In camera materials.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false In camera materials. 1025.45 Section 1025.45... PROCEEDINGS Hearings § 1025.45 In camera materials. (a) Definition. In camera materials are documents... excluded from the public record. (b) In camera treatment of documents and testimony. The Presiding Officer...

  2. Model based scattering correction in time-of-flight cameras.

    Science.gov (United States)

    Schäfer, Henrik; Lenzen, Frank; Garbe, Christoph S

    2014-12-01

    In-camera light scattering is a systematic error of Time-of-Flight depth cameras that significantly reduces the accuracy of the systems. A completely new model is presented, based on raw data calibration and only one additional intrinsic camera parameter. It is shown that the approach effectively removes the errors of in-camera light scattering.

  3. [Analog gamma camera digitalization computer system].

    Science.gov (United States)

    Rojas, G M; Quintana, J C; Jer, J; Astudillo, S; Arenas, L; Araya, H

    2004-01-01

    Digitalization of analogue gamma cameras systems, using special acquisition boards in microcomputers and appropriate software for acquisition and processing of nuclear medicine images is described in detail. Microcomputer integrated systems interconnected by means of a Local Area Network (LAN) and connected to several gamma cameras have been implemented using specialized acquisition boards. The PIP software (Portable Image Processing) was installed on each microcomputer to acquire and preprocess the nuclear medicine images. A specialized image processing software has been designed and developed for these purposes. This software allows processing of each nuclear medicine exam, in a semiautomatic procedure, and recording of the results on radiological films. . A stable, flexible and inexpensive system which makes it possible to digitize, visualize, process, and print nuclear medicine images obtained from analogue gamma cameras was implemented in the Nuclear Medicine Division. Such a system yields higher quality images than those obtained with analogue cameras while keeping operating costs considerably lower (filming: 24.6%, fixing 48.2% and developing 26%.) Analogue gamma camera systems can be digitalized economically. This system makes it possible to obtain optimal clinical quality nuclear medicine images, to increase the acquisition and processing efficiency, and to reduce the steps involved in each exam.

  4. Calibration of action cameras for photogrammetric purposes.

    Science.gov (United States)

    Balletti, Caterina; Guerra, Francesco; Tsioukas, Vassilios; Vernier, Paolo

    2014-09-18

    The use of action cameras for photogrammetry purposes is not widespread due to the fact that until recently the images provided by the sensors, using either still or video capture mode, were not big enough to perform and provide the appropriate analysis with the necessary photogrammetric accuracy. However, several manufacturers have recently produced and released new lightweight devices which are: (a) easy to handle, (b) capable of performing under extreme conditions and more importantly (c) able to provide both still images and video sequences of high resolution. In order to be able to use the sensor of action cameras we must apply a careful and reliable self-calibration prior to the use of any photogrammetric procedure, a relatively difficult scenario because of the short focal length of the camera and its wide angle lens that is used to obtain the maximum possible resolution of images. Special software, using functions of the OpenCV library, has been created to perform both the calibration and the production of undistorted scenes for each one of the still and video image capturing mode of a novel action camera, the GoPro Hero 3 camera that can provide still images up to 12 Mp and video up 8 Mp resolution.

  5. Calibration of Action Cameras for Photogrammetric Purposes

    Directory of Open Access Journals (Sweden)

    Caterina Balletti

    2014-09-01

    Full Text Available The use of action cameras for photogrammetry purposes is not widespread due to the fact that until recently the images provided by the sensors, using either still or video capture mode, were not big enough to perform and provide the appropriate analysis with the necessary photogrammetric accuracy. However, several manufacturers have recently produced and released new lightweight devices which are: (a easy to handle, (b capable of performing under extreme conditions and more importantly (c able to provide both still images and video sequences of high resolution. In order to be able to use the sensor of action cameras we must apply a careful and reliable self-calibration prior to the use of any photogrammetric procedure, a relatively difficult scenario because of the short focal length of the camera and its wide angle lens that is used to obtain the maximum possible resolution of images. Special software, using functions of the OpenCV library, has been created to perform both the calibration and the production of undistorted scenes for each one of the still and video image capturing mode of a novel action camera, the GoPro Hero 3 camera that can provide still images up to 12 Mp and video up 8 Mp resolution.

  6. Wired and Wireless Camera Triggering with Arduino

    Science.gov (United States)

    Kauhanen, H.; Rönnholm, P.

    2017-10-01

    Synchronous triggering is an important task that allows simultaneous data capture from multiple cameras. Accurate synchronization enables 3D measurements of moving objects or from a moving platform. In this paper, we describe one wired and four wireless variations of Arduino-based low-cost remote trigger systems designed to provide a synchronous trigger signal for industrial cameras. Our wireless systems utilize 315 MHz or 434 MHz frequencies with noise filtering capacitors. In order to validate the synchronization accuracy, we developed a prototype of a rotating trigger detection system (named RoTriDeS). This system is suitable to detect the triggering accuracy of global shutter cameras. As a result, the wired system indicated an 8.91 μs mean triggering time difference between two cameras. Corresponding mean values for the four wireless triggering systems varied between 7.92 and 9.42 μs. Presented values include both camera-based and trigger-based desynchronization. Arduino-based triggering systems appeared to be feasible, and they have the potential to be extended to more complicated triggering systems.

  7. Designing Camera Networks by Convex Quadratic Programming

    KAUST Repository

    Ghanem, Bernard

    2015-05-04

    ​In this paper, we study the problem of automatic camera placement for computer graphics and computer vision applications. We extend the problem formulations of previous work by proposing a novel way to incorporate visibility constraints and camera-to-camera relationships. For example, the placement solution can be encouraged to have cameras that image the same important locations from different viewing directions, which can enable reconstruction and surveillance tasks to perform better. We show that the general camera placement problem can be formulated mathematically as a convex binary quadratic program (BQP) under linear constraints. Moreover, we propose an optimization strategy with a favorable trade-off between speed and solution quality. Our solution is almost as fast as a greedy treatment of the problem, but the quality is significantly higher, so much so that it is comparable to exact solutions that take orders of magnitude more computation time. Because it is computationally attractive, our method also allows users to explore the space of solutions for variations in input parameters. To evaluate its effectiveness, we show a range of 3D results on real-world floorplans (garage, hotel, mall, and airport). ​

  8. Ophthalmic photography using a digital camera.

    Directory of Open Access Journals (Sweden)

    Fogla Rajesh

    2003-01-01

    Full Text Available Purpose: To report the application of a digital camera for ophthalmic photography in routine clinical use. Methods: A digital camera (Nikon Coolpix 995 was used both for external macrophotography of the eye and ocular adnexa, and slitlamp photography of the anterior segment of the eye. Results: We were able to take external macrophotographs under high magnification of the eye and ocular adnexa. Slitlamp photography could be performed under diffuse, slit beam, and retroillumination. The structures of the angle, the optic disc and surrounding retina could be photographed using appropriate lenses. The attachment to the operating microscope allowed intra-operative photography. It could also be attached to the laboratory microscope to capture images of various histopathology and microbiology slides. Conclusions: A digital camera is a versatile instrument for ophthalmic photography. It is easy to use in routine clinical practice and provides good quality photographs.

  9. Experiments with synchronized sCMOS cameras

    Science.gov (United States)

    Steele, Iain A.; Jermak, Helen; Copperwheat, Chris M.; Smith, Robert J.; Poshyachinda, Saran; Soonthorntham, Boonrucksar

    2016-07-01

    Scientific-CMOS (sCMOS) cameras can combine low noise with high readout speeds and do not suffer the charge multiplication noise that effectively reduces the quantum efficiency of electron multiplying CCDs by a factor 2. As such they have strong potential in fast photometry and polarimetry instrumentation. In this paper we describe the results of laboratory experiments using a pair of commercial off the shelf sCMOS cameras based around a 4 transistor per pixel architecture. In particular using a both stable and a pulsed light sources we evaluate the timing precision that may be obtained when the cameras readouts are synchronized either in software or electronically. We find that software synchronization can introduce an error of 200-msec. With electronic synchronization any error is below the limit ( 50-msec) of our simple measurement technique.

  10. HIGH SPEED KERR CELL FRAMING CAMERA

    Science.gov (United States)

    Goss, W.C.; Gilley, L.F.

    1964-01-01

    The present invention relates to a high speed camera utilizing a Kerr cell shutter and a novel optical delay system having no moving parts. The camera can selectively photograph at least 6 frames within 9 x 10/sup -8/ seconds during any such time interval of an occurring event. The invention utilizes particularly an optical system which views and transmits 6 images of an event to a multi-channeled optical delay relay system. The delay relay system has optical paths of successively increased length in whole multiples of the first channel optical path length, into which optical paths the 6 images are transmitted. The successively delayed images are accepted from the exit of the delay relay system by an optical image focusing means, which in turn directs the images into a Kerr cell shutter disposed to intercept the image paths. A camera is disposed to simultaneously view and record the 6 images during a single exposure of the Kerr cell shutter. (AEC)

  11. Modifications in infrared intraoperative neuromonitoring camera and supports.

    Science.gov (United States)

    Murphy, Emily Klerekoper

    2008-09-01

    At my request, modifications were made to the visual oculography (VOG) camera described in the March 2008 article in this journal: "Use of an Infrared Camera to Improve the Outcome of Facial Nerve Monitoring," Am J Electroneurodiagnostic Technol 48.:38-47. The camera now has a wider and a more distant range and a clamp onto a rod. The company (Micromedical Technologies, Inc.) has named the camera the KlereView Camera in honor of my father, Fred Klerekoper.

  12. Vasomotor assessment by camera-based photoplethysmography

    Directory of Open Access Journals (Sweden)

    Trumpp Alexander

    2016-09-01

    Full Text Available Camera-based photoplethysmography (cbPPG is a novel technique that allows the contactless acquisition of cardio-respiratory signals. Previous works on cbPPG most often focused on heart rate extraction. This contribution is directed at the assessment of vasomotor activity by means of cameras. In an experimental study, we show that vasodilation and vasoconstriction both lead to significant changes in cbPPG signals. Our findings underline the potential of cbPPG to monitor vasomotor functions in real-life applications.

  13. Structural optimization of some space camera

    Science.gov (United States)

    Ye, Jing; Wu, Mengyuan; Hu, Bin; Li, Xuyang

    2017-03-01

    Based on some space camera structure as the research subject, the statics analysis and modal analysis were studied using HyperMesh software. With the first order natural frequency being as constraint object, the topology optimization design of the original structure was made using OptiStruct software, which made the static deformation decrease by 42.4%; the fundamental frequency increase by 12.1%, effectively resolving the problem of the vibration of the circuit board components. Some further studies are necessary for the structure design of space camera.

  14. Digital Camera as Gloss Measurement Device

    Directory of Open Access Journals (Sweden)

    Mihálik A.

    2016-05-01

    Full Text Available Nowadays digital cameras with both high resolution and the high dynamic range (HDR can be considered as parallel multiple sensors producing multiple measurements at once. In this paper we describe a technique for processing the captured HDR data and than fit them to theoretical surface reflection models in the form of bidirectional reflectance distribution function (BRDF. Finally, the tabular BRDF can be used to calculate the gloss reflection of the surface. We compare the captured glossiness by digital camera with gloss measured with the industry device and conclude that the results fit well in our experiments.

  15. Camera-enabled techniques for organic synthesis

    Science.gov (United States)

    Ingham, Richard J; O’Brien, Matthew; Browne, Duncan L

    2013-01-01

    Summary A great deal of time is spent within synthetic chemistry laboratories on non-value-adding activities such as sample preparation and work-up operations, and labour intensive activities such as extended periods of continued data collection. Using digital cameras connected to computer vision algorithms, camera-enabled apparatus can perform some of these processes in an automated fashion, allowing skilled chemists to spend their time more productively. In this review we describe recent advances in this field of chemical synthesis and discuss how they will lead to advanced synthesis laboratories of the future. PMID:23766820

  16. Analysis of Brown camera distortion model

    Science.gov (United States)

    Nowakowski, Artur; Skarbek, Władysław

    2013-10-01

    Contemporary image acquisition devices introduce optical distortion into image. It results in pixel displacement and therefore needs to be compensated for many computer vision applications. The distortion is usually modeled by the Brown distortion model, which parameters can be included in camera calibration task. In this paper we describe original model, its dependencies and analyze orthogonality with regard to radius for its decentering distortion component. We also report experiments with camera calibration algorithm included in OpenCV library, especially a stability of distortion parameters estimation is evaluated.

  17. Increased Automation in Stereo Camera Calibration Techniques

    Directory of Open Access Journals (Sweden)

    Brandi House

    2006-08-01

    Full Text Available Robotic vision has become a very popular field in recent years due to the numerous promising applications it may enhance. However, errors within the cameras and in their perception of their environment can cause applications in robotics to fail. To help correct these internal and external imperfections, stereo camera calibrations are performed. There are currently many accurate methods of camera calibration available; however, most or all of them are time consuming and labor intensive. This research seeks to automate the most labor intensive aspects of a popular calibration technique developed by Jean-Yves Bouguet. His process requires manual selection of the extreme corners of a checkerboard pattern. The modified process uses embedded LEDs in the checkerboard pattern to act as active fiducials. Images are captured of the checkerboard with the LEDs on and off in rapid succession. The difference of the two images automatically highlights the location of the four extreme corners, and these corner locations take the place of the manual selections. With this modification to the calibration routine, upwards of eighty mouse clicks are eliminated per stereo calibration. Preliminary test results indicate that accuracy is not substantially affected by the modified procedure. Improved automation to camera calibration procedures may finally penetrate the barriers to the use of calibration in practice.

  18. Camera for Quasars in Early Universe (CQUEAN)

    Science.gov (United States)

    Park, Won-Kee; Pak, Soojong; Im, Myungshin; Choi, Changsu; Jeon, Yiseul; Chang, Seunghyuk; Jeong, Hyeonju; Lim, Juhee; Kim, Eunbin

    2012-08-01

    We describe the overall characteristics and the performance of an optical CCD camera system, Camera for Quasars in Early Universe (CQUEAN), which has been used at the 2.1 m Otto Struve Telescope of the McDonald Observatory since 2010 August. CQUEAN was developed for follow-up imaging observations of red sources such as high-redshift quasar candidates (z ≳ 5), gamma-ray bursts, brown dwarfs, and young stellar objects. For efficient observations of the red objects, CQUEAN has a science camera with a deep-depletion CCD chip, which boasts a higher quantum efficiency at 0.7-1.1 μm than conventional CCD chips. The camera was developed in a short timescale () and has been working reliably. By employing an autoguiding system and a focal reducer to enhance the field of view on the classical Cassegrain focus, we achieve a stable guiding in 20 minute exposures, an imaging quality with FWHM≥0.6‧‧ over the whole field (4.8‧ × 4.8‧), and a limiting magnitude of z = 23.4 AB mag at 5-σ with 1 hr total integration time. This article includes data taken at the McDonald Observatory of The University of Texas at Austin.

  19. GAMPIX: A new generation of gamma camera

    Science.gov (United States)

    Gmar, M.; Agelou, M.; Carrel, F.; Schoepff, V.

    2011-10-01

    Gamma imaging is a technique of great interest in several fields such as homeland security or decommissioning/dismantling of nuclear facilities in order to localize hot spots of radioactivity. In the nineties, previous works led by CEA LIST resulted in the development of a first generation of gamma camera called CARTOGAM, now commercialized by AREVA CANBERRA. Even if its performances can be adapted to many applications, its weight of 15 kg can be an issue. For several years, CEA LIST has been developing a new generation of gamma camera, called GAMPIX. This system is mainly based on the Medipix2 chip, hybridized to a 1 mm thick CdTe substrate. A coded mask replaces the pinhole collimator in order to increase the sensitivity of the gamma camera. Hence, we obtained a very compact device (global weight less than 1 kg without any shielding), which is easy to handle and to use. In this article, we present the main characteristics of GAMPIX and we expose the first experimental results illustrating the performances of this new generation of gamma camera.

  20. Case on Camera--An Audience Verdict.

    Science.gov (United States)

    Wober, J. M.

    In July 1984, British Channel 4 began televising Case on Camera, a series based on genuine arbitration of civil cases carried out by a retired judge, recorded as it happened, and edited into half hour programs. Because of the Independent Broadcasting Authority's concern for the rights to privacy, a systematic study of public reaction to the series…

  1. Face identification in videos from mobile cameras

    NARCIS (Netherlands)

    Mu, Meiru; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2014-01-01

    It is still challenging to recognize faces reliably in videos from mobile camera, although mature automatic face recognition technology for still images has been available for quite some time. Suppose we want to be alerted when suspects appear in the recording of a police Body-Cam, even a good face

  2. Teaching Camera Calibration by a Constructivist Methodology

    Science.gov (United States)

    Samper, D.; Santolaria, J.; Pastor, J. J.; Aguilar, J. J.

    2010-01-01

    This article describes the Metrovisionlab simulation software and practical sessions designed to teach the most important machine vision camera calibration aspects in courses for senior undergraduate students. By following a constructivist methodology, having received introductory theoretical classes, students use the Metrovisionlab application to…

  3. Phase camera experiment for Advanced Virgo

    NARCIS (Netherlands)

    Agatsuma, Kazuhiro; Van Beuzekom, Martin; Van Der Schaaf, Laura; Van Den Brand, Jo

    2016-01-01

    We report on a study of the phase camera, which is a frequency selective wave-front sensor of a laser beam. This sensor is utilized for monitoring sidebands produced by phase modulations in a gravitational wave (GW) detector. Regarding the operation of the GW detectors, the laser

  4. Lights, Camera, Read! Arizona Reading Program Manual.

    Science.gov (United States)

    Arizona State Dept. of Library, Archives and Public Records, Phoenix.

    This document is the manual for the Arizona Reading Program (ARP) 2003 entitled "Lights, Camera, Read!" This theme spotlights books that were made into movies, and allows readers to appreciate favorite novels and stories that have progressed to the movie screen. The manual consists of eight sections. The Introduction includes welcome…

  5. Digital Camera Control for Faster Inspection

    Science.gov (United States)

    Brown, Katharine; Siekierski, James D.; Mangieri, Mark L.; Dekome, Kent; Cobarruvias, John; Piplani, Perry J.; Busa, Joel

    2009-01-01

    Digital Camera Control Software (DCCS) is a computer program for controlling a boom and a boom-mounted camera used to inspect the external surface of a space shuttle in orbit around the Earth. Running in a laptop computer in the space-shuttle crew cabin, DCCS commands integrated displays and controls. By means of a simple one-button command, a crewmember can view low- resolution images to quickly spot problem areas and can then cause a rapid transition to high- resolution images. The crewmember can command that camera settings apply to a specific small area of interest within the field of view of the camera so as to maximize image quality within that area. DCCS also provides critical high-resolution images to a ground screening team, which analyzes the images to assess damage (if any); in so doing, DCCS enables the team to clear initially suspect areas more quickly than would otherwise be possible and further saves time by minimizing the probability of re-imaging of areas already inspected. On the basis of experience with a previous version (2.0) of the software, the present version (3.0) incorporates a number of advanced imaging features that optimize crewmember capability and efficiency.

  6. X-ray imaging using digital cameras

    Science.gov (United States)

    Winch, Nicola M.; Edgar, Andrew

    2012-03-01

    The possibility of using the combination of a computed radiography (storage phosphor) cassette and a semiprofessional grade digital camera for medical or dental radiography is investigated. We compare the performance of (i) a Canon 5D Mk II single lens reflex camera with f1.4 lens and full-frame CMOS array sensor and (ii) a cooled CCD-based camera with a 1/3 frame sensor and the same lens system. Both systems are tested with 240 x 180 mm cassettes which are based on either powdered europium-doped barium fluoride bromide or needle structure europium-doped cesium bromide. The modulation transfer function for both systems has been determined and falls to a value of 0.2 at around 2 lp/mm, and is limited by light scattering of the emitted light from the storage phosphor rather than the optics or sensor pixelation. The modulation transfer function for the CsBr:Eu2+ plate is bimodal, with a high frequency wing which is attributed to the light-guiding behaviour of the needle structure. The detective quantum efficiency has been determined using a radioisotope source and is comparatively low at 0.017 for the CMOS camera and 0.006 for the CCD camera, attributed to the poor light harvesting by the lens. The primary advantages of the method are portability, robustness, digital imaging and low cost; the limitations are the low detective quantum efficiency and hence signal-to-noise ratio for medical doses, and restricted range of plate sizes. Representative images taken with medical doses are shown and illustrate the potential use for portable basic radiography.

  7. A novel fully integrated handheld gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Massari, R.; Ucci, A.; Campisi, C. [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy); Scopinaro, F. [University of Rome “La Sapienza”, S. Andrea Hospital, Rome (Italy); Soluri, A., E-mail: alessandro.soluri@ibb.cnr.it [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy)

    2016-10-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  8. Modulated CMOS camera for fluorescence lifetime microscopy.

    Science.gov (United States)

    Chen, Hongtao; Holst, Gerhard; Gratton, Enrico

    2015-12-01

    Widefield frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) is a fast and accurate method to measure the fluorescence lifetime of entire images. However, the complexity and high costs involved in construction of such a system limit the extensive use of this technique. PCO AG recently released the first luminescence lifetime imaging camera based on a high frequency modulated CMOS image sensor, QMFLIM2. Here we tested and provide operational procedures to calibrate the camera and to improve the accuracy using corrections necessary for image analysis. With its flexible input/output options, we are able to use a modulated laser diode or a 20 MHz pulsed white supercontinuum laser as the light source. The output of the camera consists of a stack of modulated images that can be analyzed by the SimFCS software using the phasor approach. The nonuniform system response across the image sensor must be calibrated at the pixel level. This pixel calibration is crucial and needed for every camera settings, e.g. modulation frequency and exposure time. A significant dependency of the modulation signal on the intensity was also observed and hence an additional calibration is needed for each pixel depending on the pixel intensity level. These corrections are important not only for the fundamental frequency, but also for the higher harmonics when using the pulsed supercontinuum laser. With these post data acquisition corrections, the PCO CMOS-FLIM camera can be used for various biomedical applications requiring a large frame and high speed acquisition. © 2015 Wiley Periodicals, Inc.

  9. A Precision Analysis of Camera Distortion Models.

    Science.gov (United States)

    Tang, Zhongwei; Grompone von Gioi, Rafael; Monasse, Pascal; Morel, Jean-Michel

    2017-06-01

    This paper addresses the question of identifying the right camera direct or inverse distortion model, permitting a high subpixel precision to fit to real camera distortion. Five classic camera distortion models are reviewed and their precision is compared for direct or inverse distortion. By definition, the three radially symmetric models can only model a distortion radially symmetric around some distortion center. They can be extended to deal with non-radially symmetric distortions by adding tangential distortion components, but still may be too simple for very accurate modeling of real cameras. The polynomial and the rational models instead miss a physical or optical interpretation, but can cope equally with radially and non-radially symmetric distortions. Indeed, they do not require the evaluation of a distortion center. When requiring high precisions, we found that the distortion modeling must also be evaluated primarily as a numerical problem. Indeed, all models except the polynomial involve a non-linear minimization, which increases the numerical risk. The estimation of a polynomial distortion model leads instead to a linear problem, which is secure and much faster. We concluded by extensive numerical experiments that, although high degree polynomials were required to reach a high precision of 1/100 pixels, such polynomials were easily estimated and produced a precise distortion modeling without overfitting. Our conclusion is validated by three independent experimental setups: the models were compared first on the lens distortion database of the Lensfun library by their distortion simulation and inversion power; second by fitting real camera distortions estimated by a non parametric algorithm; and finally by the absolute correction measurement provided by the photographs of tightly stretched strings, warranting a high straightness.

  10. Construction of Double Right-Border Binary Vector Carrying Non-Host Gene Rxo1 Resistant to Bacterial Leaf Streak of Rice

    Directory of Open Access Journals (Sweden)

    Mei-rong XU

    2008-09-01

    Full Text Available Rxo1 cloned from maize is a non-host gene resistant to bacterial leaf streak of rice. pCAMBIA1305-1 with Rxo1 was digested with Sca I and NgoM IV and the double right-border binary vector pMNDRBBin6 was digested with Hpa I and Xma I. pMNDRBBin6 carrying the gene Rxo1 was acquired by ligation of blunt-end and cohesive end. The results of PCR, restriction enzyme analysis and sequencing indicated that the Rxo1 gene had been cloned into pMNDRBBin6. This double right-border binary vector, named as pMNDRBBin6-Rxo1, will play a role in breeding marker-free plants resistant to bacterial leaf streak of rice by genetic transformation.

  11. Refração por retinoscopia com luz em faixa em cães Refraction by streak retinoscopy in dogs

    Directory of Open Access Journals (Sweden)

    J.J.T. Ranzani

    2008-04-01

    Full Text Available A refração ocular por retinoscopia com luz em faixa em 10 cães normais, sem raça definida, demonstrou que a maioria dos animais, independentemente do porte, apresentou tendência à hipermetropia, além de anisometropia e astigmatismo.Ocular refraction by streak retinoscopy performed in 10 mixed breed dogs showed that most of the animals, independently of size, had a tendency to hypermetropia, anisometropia, and astigmatism.

  12. GFP is Efficiently Expressed by Wheat Streak Mosaic Virus Using a Range of Tritimovirus NIa Cleavage Sites and Forms Dense Aggregates in Cereal Hosts

    Science.gov (United States)

    Wheat streak mosaic virus (WSMV)-based transient expression vector was developed to express GFP as a marker protein. The GFP cistron was engineered between the P1 and HC-Pro cistrons in an infectious cDNA clone of WSMV. The cleavage sites, P3/6KI, 6KI/CI, NIa/NIb, or NIb/CP, from WSMV were fused to ...

  13. Expression of a rice chitinase gene in transgenic banana ('Gros Michel', AAA genome group) confers resistance to black leaf streak disease

    OpenAIRE

    Kovacs, Gabriella; Sagi; Jacon, Géraldine; Arinaitwe, Geofrey; Busogoro, Jean-Pierre; Thiry, Els; Strosse, Hannelore; Swennen, Rony; Remy, Serge

    2013-01-01

    Transgenic banana (Musa acuminata ?Gros Michel?) integrating either of two rice chitinase genes was generated and its resistance to Black Leaf Streak disease caused by the fungus Mycosphaerella fijiensis was tested using a leaf disk bioassay. PCR screening indicated the presence of the hpt selectable marker gene in more than 90?% of the lines tested, whereas more than three quarters of the lines contained the linked rice chitinase gene resulting in a co-transformation frequency of at least 71...

  14. Control of the movement of a ROV camera; Controle de posicionamento da camera de um ROV

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alexandre S. de; Dutra, Max Suell [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE); Reis, Ney Robinson S. dos [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; Santos, Auderi V. dos [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The ROV's (Remotely Operated Vehicles) are used for installation and maintenance of underwater exploration systems in the oil industry. These systems are operated in distant areas thus being of essential importance the use of a cameras for the visualization of the work area. The synchronization necessary in the accomplishment of the tasks when operating the manipulator and the movement of the camera for the operator is a complex task. For the accomplishment of this synchronization is presented in this work the analysis of the interconnection of the systems. The concatenation of the systems is made through the interconnection of the electric signals of the proportional valves of the actuators of the manipulator with the signals of the proportional valves of the actuators of the camera. With this interconnection the approach accompaniment of the movement of the manipulator for the camera, keeping the object of the visualization of the field of vision of the operator is obtained. (author)

  15. Crystallographic analysis reveals octamerization of viroplasm matrix protein P9-1 of Rice black streaked dwarf virus.

    Science.gov (United States)

    Akita, Fusamichi; Higashiura, Akifumi; Shimizu, Takumi; Pu, Yingying; Suzuki, Mamoru; Uehara-Ichiki, Tamaki; Sasaya, Takahide; Kanamaru, Shuji; Arisaka, Fumio; Tsukihara, Tomitake; Nakagawa, Atsushi; Omura, Toshihiro

    2012-01-01

    The P9-1 protein of Rice black streaked dwarf virus accumulates in viroplasm inclusions, which are structures that appear to play an important role in viral morphogenesis and are commonly found in viruses in the family Reoviridae. Crystallographic analysis of P9-1 revealed structural features that allow the protein to form dimers via hydrophobic interactions. Each dimer has carboxy-terminal regions, resembling arms, that extend to neighboring dimers, thereby uniting sets of four dimers via lateral hydrophobic interactions, to yield cylindrical octamers. The importance of these regions for the formation of viroplasm-like inclusions was confirmed by the absence of such inclusions when P9-1 was expressed without its carboxy-terminal arm. The octamers are vertically elongated cylinders resembling the structures formed by NSP2 of rotavirus, even though there are no significant similarities between the respective primary and secondary structures of the two proteins. Our results suggest that an octameric structure with an internal pore might be important for the functioning of the respective proteins in the events that occur in the viroplasm, which might include viral morphogenesis.

  16. Evolution of Endogenous Sequences of Banana Streak Virus: What Can We Learn from Banana (Musa sp.) Evolution?▿

    Science.gov (United States)

    Gayral, Philippe; Blondin, Laurence; Guidolin, Olivier; Carreel, Françoise; Hippolyte, Isabelle; Perrier, Xavier; Iskra-Caruana, Marie-Line

    2010-01-01

    Endogenous plant pararetroviruses (EPRVs) are viral sequences of the family Caulimoviridae integrated into the nuclear genome of numerous plant species. The ability of some endogenous sequences of Banana streak viruses (eBSVs) in the genome of banana (Musa sp.) to induce infections just like the virus itself was recently demonstrated (P. Gayral et al., J. Virol. 83:6697-6710, 2008). Although eBSVs probably arose from accidental events, infectious eBSVs constitute an extreme case of parasitism, as well as a newly described strategy for vertical virus transmission in plants. We investigated the early evolutionary stages of infectious eBSV for two distinct BSV species—GF (BSGFV) and Imové (BSImV)—through the study of their distribution, insertion polymorphism, and structure evolution among selected banana genotypes representative of the diversity of 60 wild Musa species and genotypes. To do so, the historical frame of host evolution was analyzed by inferring banana phylogeny from two chloroplast regions—matK and trnL-trnF—as well as from the nuclear genome, using 19 microsatellite loci. We demonstrated that both BSV species integrated recently in banana evolution, circa 640,000 years ago. The two infectious eBSVs were subjected to different selective pressures and showed distinct levels of rearrangement within their final structure. In addition, the molecular phylogenies of integrated and nonintegrated BSVs enabled us to establish the phylogenetic origins of eBSGFV and eBSImV. PMID:20427523

  17. Evolution of endogenous sequences of banana streak virus: what can we learn from banana (Musa sp.) evolution?

    Science.gov (United States)

    Gayral, Philippe; Blondin, Laurence; Guidolin, Olivier; Carreel, Françoise; Hippolyte, Isabelle; Perrier, Xavier; Iskra-Caruana, Marie-Line

    2010-07-01

    Endogenous plant pararetroviruses (EPRVs) are viral sequences of the family Caulimoviridae integrated into the nuclear genome of numerous plant species. The ability of some endogenous sequences of Banana streak viruses (eBSVs) in the genome of banana (Musa sp.) to induce infections just like the virus itself was recently demonstrated (P. Gayral et al., J. Virol. 83:6697-6710, 2008). Although eBSVs probably arose from accidental events, infectious eBSVs constitute an extreme case of parasitism, as well as a newly described strategy for vertical virus transmission in plants. We investigated the early evolutionary stages of infectious eBSV for two distinct BSV species-GF (BSGFV) and Imové (BSImV)-through the study of their distribution, insertion polymorphism, and structure evolution among selected banana genotypes representative of the diversity of 60 wild Musa species and genotypes. To do so, the historical frame of host evolution was analyzed by inferring banana phylogeny from two chloroplast regions-matK and trnL-trnF-as well as from the nuclear genome, using 19 microsatellite loci. We demonstrated that both BSV species integrated recently in banana evolution, circa 640,000 years ago. The two infectious eBSVs were subjected to different selective pressures and showed distinct levels of rearrangement within their final structure. In addition, the molecular phylogenies of integrated and nonintegrated BSVs enabled us to establish the phylogenetic origins of eBSGFV and eBSImV.

  18. Phylogeny of Banana Streak Virus reveals recent and repetitive endogenization in the genome of its banana host (Musa sp.).

    Science.gov (United States)

    Gayral, Philippe; Iskra-Caruana, Marie-Line

    2009-07-01

    Banana streak virus (BSV) is a plant dsDNA pararetrovirus (family Caulimoviridae, genus badnavirus). Although integration is not an essential step in the BSV replication cycle, the nuclear genome of banana (Musa sp.) contains BSV endogenous pararetrovirus sequences (BSV EPRVs). Some BSV EPRVs are infectious by reconstituting a functional viral genome. Recent studies revealed a large molecular diversity of episomal BSV viruses (i.e., nonintegrated) while others focused on BSV EPRV sequences only. In this study, the evolutionary history of badnavirus integration in banana was inferred from phylogenetic relationships between BSV and BSV EPRVs. The relative evolution rates and selective pressures (d(N)/d(S) ratio) were also compared between endogenous and episomal viral sequences. At least 27 recent independent integration events occurred after the divergence of three banana species, indicating that viral integration is a recent and frequent phenomenon. Relaxation of selective pressure on badnaviral sequences that experienced neutral evolution after integration in the plant genome was recorded. Additionally, a significant decrease (35%) in the EPRV evolution rate was observed compared to BSV, reflecting the difference in the evolution rate between episomal dsDNA viruses and plant genome. The comparison of our results with the evolution rate of the Musa genome and other reverse-transcribing viruses suggests that EPRVs play an active role in episomal BSV diversity and evolution.

  19. Crystallization and preliminary X-ray characterization of tobacco streak virus and a proteolytically modified form of the capsid protein.

    Science.gov (United States)

    Sehnke, P C; Johnson, J E

    1993-09-01

    Isolated tobacco streak virus strain mild (TSV-M) top nucleoprotein component (TV) was crystallized by vapor diffusion with polyethylene glycol (PEG) and methyl pentanediol. The morphology of the crystal suggested a hexagonal space group, however, the crystals were disordered as analyzed by X-ray diffraction. Capsid protein from TSV (strains M and white clover) was treated with trypsin to remove 87 amino terminal residues. The modified capsid protein was purified by ion exchange chromatography and crystallized in both hexagonal and triclinic forms. Hexagonal crystals grown by vapor diffusion in PEG diffract X rays to 4.5 A. The crystals, in the space group P6(2) or its enantiomorph, possess unit cell dimensions of a = 98.3 A, c = 108.7 A and probably contain 12 dimers/unit cell. Triclinic crystals grown by vapor diffusion in ammonium sulfate diffracted X rays to 2.4 A resolution when exposed to X-ray synchrotron radiation. The crystals have unit cell dimensions of a = 60.1 A, b = 77.5 A, c = 73.9 A with alpha = 67.8 degrees, beta = 130 degrees, and gamma = 106 degrees and probably contain 4 dimers/unit cell.

  20. Long-Term Follow-Up of Polypoidal Choroidal Vasculopathy Secondary to Angioid Streaks Treated by Intravitreal Aflibercept and Ranibizumab

    Directory of Open Access Journals (Sweden)

    James G. Wong

    2017-04-01

    Full Text Available Purpose: Angioid streaks (AS are dehiscences in Bruch’s membrane that may be idiopathic or associated with numerous systemic illnesses. Polypoidal choroidal vasculopathy (PCV is an underdiagnosed exudative chorioretinopathy often characterised by serosanguineous detachments of the pigmented epithelium. The use of the anti-VEGF agents ranibizumab and aflibercept in the management of PCV secondary to AS has not been previously documented. We report 3 patients with active PCV secondary to AS, 1 of which had a family history of PCV secondary to AS, not previously reported in the literature. All patients were symptomatic and treated with intravitreal anti-VEGF therapy with and without combination photodynamic therapy (PDT. Methods: This is a long-term retrospective case review of 3 eyes of 3 patients with AS and clinical features of PCV. The patients were examined using fundoscopy, spectral domain optical coherence tomography, fluorescein angiography, and indocyanine green angiography. All patients were managed with intravitreal anti-VEGF using a treat-and-extend protocol according to specific retreatment criteria. One patient had 1 session of PDT in combination with anti-VEGF injections. Results: The mean follow-up time in all patients was 4 years. In all 3 cases, the treatment resulted in improved visual acuity and regression of active PCV lesions with a longer duration between injections. Conclusion: The treat-and-extend protocol with intravitreal aflibercept or ranibizumab with or without PDT is effective and safe for PCV secondary to AS.

  1. Jasmonic acid-mediated defense suppresses brassinosteroid-mediated susceptibility to Rice black streaked dwarf virus infection in rice.

    Science.gov (United States)

    He, Yuqing; Zhang, Hehong; Sun, Zongtao; Li, Junmin; Hong, Gaojie; Zhu, Qisong; Zhou, Xuebiao; MacFarlane, Stuart; Yan, Fei; Chen, Jianping

    2017-04-01

    Plant hormones play a vital role in plant immune responses. However, in contrast to the relative wealth of information on hormone-mediated immunity in dicot plants, little information is available on monocot-virus defense systems. We used a high-throughput-sequencing approach to compare the global gene expression of Rice black-streaked dwarf virus (RBSDV)-infected rice plants with that of healthy plants. Exogenous hormone applications and transgenic rice were used to test RBSDV infectivity and pathogenicity. Our results revealed that the jasmonic acid (JA) pathway was induced while the brassinosteroid (BR) pathway was suppressed in infected plants. Foliar application of methyl jasmonate (MeJA) or brassinazole (BRZ) resulted in a significant reduction in RBSDV incidence, while epibrassinolide (BL) treatment increased RBSDV infection. Infection studies using coi1-13 and Go mutants demonstrated JA-mediated resistance and BR-mediated susceptibility to RBSDV infection. A mixture of MeJA and BL treatment resulted in a significant reduction in RBSDV infection compared with a single BL treatment. MeJA application efficiently suppressed the expression of BR pathway genes, and this inhibition depended on the JA coreceptor OsCOI1. Collectively, our results reveal that JA-mediated defense can suppress the BR-mediated susceptibility to RBSDV infection. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  2. Structure and components of the globular and filamentous viroplasms induced by Rice black-streaked dwarf virus.

    Science.gov (United States)

    Xie, Li; Lv, Ming-Fang; Song, Xi-Jiao; Yang, Jian; Li, Jing; Sun, Zong-Tao; Zhang, Ying-Yi; Chen, Jian-Ping; Zhang, Heng-Mu

    2017-07-01

    Viroplasms of members of the family Reoviridae are considered to be viral factories for genome replication and virion assembly. Globular and filamentous phenotypes have different components and probably have different functions. We used transmission electron microscopy and electron tomography to examine the structure and components of the two viroplasm phenotypes induced by Rice black-streaked dwarf virus (RBSDV). Immuno-gold labeling was used to localize each of the 13 RBSDV encoded proteins as well as double-stranded RNA, host cytoskeleton actin-11 and α-tubulin. Ten of the RBSDV proteins were localized in one or both types of viroplasm. P5-1, P6 and P9-1 were localized on both viroplasm phenotypes but P5-1 was preferentially associated with filaments and P9-1 with the matrix. Structural analysis by electron tomography showed that osmiophilic granules 6-8nm in diameter served as the fundamental unit for constructing both of the viroplasm phenotypes but were more densely packed in the filamentous phenotype. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. NATIONAL GUIDELINES FOR DIGITAL CAMERA SYSTEMS CERTIFICATION

    Directory of Open Access Journals (Sweden)

    Y. Yaron

    2016-06-01

    Full Text Available Digital camera systems are a key component in the production of reliable, geometrically accurate, high-resolution geospatial products. These systems have replaced film imaging in photogrammetric data capturing. Today, we see a proliferation of imaging sensors collecting photographs in different ground resolutions, spectral bands, swath sizes, radiometric characteristics, accuracies and carried on different mobile platforms. In addition, these imaging sensors are combined with navigational tools (such as GPS and IMU, active sensors such as laser scanning and powerful processing tools to obtain high quality geospatial products. The quality (accuracy, completeness, consistency, etc. of these geospatial products is based on the use of calibrated, high-quality digital camera systems. The new survey regulations of the state of Israel specify the quality requirements for each geospatial product including: maps at different scales and for different purposes, elevation models, orthophotographs, three-dimensional models at different levels of details (LOD and more. In addition, the regulations require that digital camera systems used for mapping purposes should be certified using a rigorous mapping systems certification and validation process which is specified in the Director General Instructions. The Director General Instructions for digital camera systems certification specify a two-step process as follows: 1. Theoretical analysis of system components that includes: study of the accuracy of each component and an integrative error propagation evaluation, examination of the radiometric and spectral response curves for the imaging sensors, the calibration requirements, and the working procedures. 2. Empirical study of the digital mapping system that examines a typical project (product scale, flight height, number and configuration of ground control points and process. The study examine all the aspects of the final product including; its accuracy, the

  4. National Guidelines for Digital Camera Systems Certification

    Science.gov (United States)

    Yaron, Yaron; Keinan, Eran; Benhamu, Moshe; Regev, Ronen; Zalmanzon, Garry

    2016-06-01

    Digital camera systems are a key component in the production of reliable, geometrically accurate, high-resolution geospatial products. These systems have replaced film imaging in photogrammetric data capturing. Today, we see a proliferation of imaging sensors collecting photographs in different ground resolutions, spectral bands, swath sizes, radiometric characteristics, accuracies and carried on different mobile platforms. In addition, these imaging sensors are combined with navigational tools (such as GPS and IMU), active sensors such as laser scanning and powerful processing tools to obtain high quality geospatial products. The quality (accuracy, completeness, consistency, etc.) of these geospatial products is based on the use of calibrated, high-quality digital camera systems. The new survey regulations of the state of Israel specify the quality requirements for each geospatial product including: maps at different scales and for different purposes, elevation models, orthophotographs, three-dimensional models at different levels of details (LOD) and more. In addition, the regulations require that digital camera systems used for mapping purposes should be certified using a rigorous mapping systems certification and validation process which is specified in the Director General Instructions. The Director General Instructions for digital camera systems certification specify a two-step process as follows: 1. Theoretical analysis of system components that includes: study of the accuracy of each component and an integrative error propagation evaluation, examination of the radiometric and spectral response curves for the imaging sensors, the calibration requirements, and the working procedures. 2. Empirical study of the digital mapping system that examines a typical project (product scale, flight height, number and configuration of ground control points and process). The study examine all the aspects of the final product including; its accuracy, the product pixels size

  5. World's fastest and most sensitive astronomical camera

    Science.gov (United States)

    2009-06-01

    The next generation of instruments for ground-based telescopes took a leap forward with the development of a new ultra-fast camera that can take 1500 finely exposed images per second even when observing extremely faint objects. The first 240x240 pixel images with the world's fastest high precision faint light camera were obtained through a collaborative effort between ESO and three French laboratories from the French Centre National de la Recherche Scientifique/Institut National des Sciences de l'Univers (CNRS/INSU). Cameras such as this are key components of the next generation of adaptive optics instruments of Europe's ground-based astronomy flagship facility, the ESO Very Large Telescope (VLT). ESO PR Photo 22a/09 The CCD220 detector ESO PR Photo 22b/09 The OCam camera ESO PR Video 22a/09 OCam images "The performance of this breakthrough camera is without an equivalent anywhere in the world. The camera will enable great leaps forward in many areas of the study of the Universe," says Norbert Hubin, head of the Adaptive Optics department at ESO. OCam will be part of the second-generation VLT instrument SPHERE. To be installed in 2011, SPHERE will take images of giant exoplanets orbiting nearby stars. A fast camera such as this is needed as an essential component for the modern adaptive optics instruments used on the largest ground-based telescopes. Telescopes on the ground suffer from the blurring effect induced by atmospheric turbulence. This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it blurs the finest details of the images. Adaptive optics techniques overcome this major drawback, so that ground-based telescopes can produce images that are as sharp as if taken from space. Adaptive optics is based on real-time corrections computed from images obtained by a special camera working at very high speeds. Nowadays, this means many hundreds of times each second. The new generation instruments require these

  6. Test of the CLAS12 RICH large-scale prototype in the direct proximity focusing configuration

    Energy Technology Data Exchange (ETDEWEB)

    Anefalos Pereira, S.; Lucherini, V.; Mirazita, M.; Orlandi, A.; Orecchini, D.; Pisano, S.; Tomassini, S.; Viticchie, A. [Laboratori Nazionali di Frascati, INFN, Frascati (Italy); Baltzell, N.; El Alaoui, A.; Hafidi, K. [Physics Division, Argonne National Laboratory, Argonne, IL (United States); Barion, L.; Contalbrigo, M.; Malaguti, R.; Movsisyan, A.; Pappalardo, L.L.; Squerzanti, S. [INFN, Ferrara (Italy); Benmokhtar, F. [Department of Physics, Duquesne University, Pittsburgh, PA (United States); Brooks, W. [Universidad Tecnica Federico Santa Maria, Valparaiso (Chile); Cisbani, E. [Gruppo Sanita and Istituto Superiore di Sanita, INFN, Rome (Italy); Hoek, M.; Phillips, J. [School of Physics and Astronomy, Kelvin Building, University of Glasgow, Scotland (United Kingdom); Kubarovsky, V. [Thomas Jefferson National Accelerator Facility, Jefferson Laboratory, Newport News, VA (United States); Lagamba, L.; Perrino, R. [INFN, Bari (Italy); Montgomery, R.A. [Laboratori Nazionali di Frascati, INFN, Frascati (Italy); School of Physics and Astronomy, Kelvin Building, University of Glasgow, Scotland (United Kingdom); Musico, P. [INFN, Genova (Italy); Rossi, P. [Laboratori Nazionali di Frascati, INFN, Frascati (Italy); Thomas Jefferson National Accelerator Facility, Jefferson Laboratory, Newport News, VA (United States); Turisini, M. [INFN, Ferrara (Italy); Universidad Tecnica Federico Santa Maria, Valparaiso (Chile)

    2016-02-15

    A large-area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3GeV/c up to 8GeV/c for the CLAS12 experiment at the upgraded 12GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and highly packed and highly segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large-angle tracks). We report here the results of the tests of a large-scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1: 500 in the whole momentum range. (orig.)

  7. Test of the CLAS12 RICH large scale prototype in the direct proximity focusing configuration

    CERN Document Server

    Anefalos Pereira, S; Barion, L.; Benmokhtar, F; Brooks, W; Cisbani, E; Contalbrigo, M; El Alaoui, A; Hafidi, K; Hoek, M; Kubarovsky, V; Lagamba, L; Lucherini, V; Malaguti, R; Mirazita, M; Montgomery, R A; Movsisyan, A; Musico, P; Orlandi, A; Orecchini, D; Pappalardo, L L; Perrino, R; Phillips, J; Pisano, S; Rossi, P; Squerzanti, S; Tomassini, S; Turisini, M; Viticchiè, A

    2016-01-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c up to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and high-packed and high-segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). We report here the results of the tests of a large scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1:500 in the whole momentum range.

  8. Test of the CLAS12 RICH large-scale prototype in the direct proximity focusing configuration

    Energy Technology Data Exchange (ETDEWEB)

    Anefalos Pereira, S.; Baltzell, N.; Barion, L.; Benmokhtar, F.; Brooks, W.; Cisbani, E.; Contalbrigo, M.; El Alaoui, A.; Hafidi, K.; Hoek, M.; Kubarovsky, V.; Lagamba, L.; Lucherini, V.; Malaguti, R.; Mirazita, M.; Montgomery, R. A.; Movsisyan, A.; Musico, P.; Orlandi, A.; Orecchini, D.; Pappalardo, L. L.; Perrino, R.; Phillips, J.; Pisano, S.; Rossi, P.; Squerzanti, S.; Tomassini, S.; Turisini, M.; Viticchiè, A.

    2016-02-11

    A large-area ring-imaging Cherenkov detector has been designed to provide clean hadron identi- fication capability in the momentum range from 3 GeV/c up to 8 GeV/c for the CLAS12 experiment at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and highly packed and highly segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large-angle tracks). We report here the results of the tests of a large-scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1 : 500 in the whole momentum range.

  9. Test of the CLAS12 Rich Large Scale Prototype in the Direct Proximity Focusing Configuration

    Energy Technology Data Exchange (ETDEWEB)

    Anefalos Pereira, S.; Baltzell, N.; Barion, L.; Benmokhtar, F.; Brooks, W. K.; Cisbani, E.; Contalbrigo, M.; El Alaoui, A.; Hafidi, K.; Hoek, M.

    2016-02-11

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c up to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and high-packed and high-segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). We report here the results of the tests of a large scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1:500 in the whole momentum range.

  10. GPM GROUND VALIDATION DC-8 CAMERA NADIR GCPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation DC-8 Camera Nadir GCPEx dataset contains geo-located visible-wavelength imagery of the ground obtained from the nadir camera aboard the...

  11. GPM GROUND VALIDATION DC-8 CAMERA NADIR GCPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation DC-8 Camera Nadir GCPEx dataset contains geo-located, visible-wavelength imagery of the ground obtained from the nadir camera aboard the...

  12. Advanced EVA Suit Camera System Development Project

    Science.gov (United States)

    Mock, Kyla

    2016-01-01

    The National Aeronautics and Space Administration (NASA) at the Johnson Space Center (JSC) is developing a new extra-vehicular activity (EVA) suit known as the Advanced EVA Z2 Suit. All of the improvements to the EVA Suit provide the opportunity to update the technology of the video imagery. My summer internship project involved improving the video streaming capabilities of the cameras that will be used on the Z2 Suit for data acquisition. To accomplish this, I familiarized myself with the architecture of the camera that is currently being tested to be able to make improvements on the design. Because there is a lot of benefit to saving space, power, and weight on the EVA suit, my job was to use Altium Design to start designing a much smaller and simplified interface board for the camera's microprocessor and external components. This involved checking datasheets of various components and checking signal connections to ensure that this architecture could be used for both the Z2 suit and potentially other future projects. The Orion spacecraft is a specific project that may benefit from this condensed camera interface design. The camera's physical placement on the suit also needed to be determined and tested so that image resolution can be maximized. Many of the options of the camera placement may be tested along with other future suit testing. There are multiple teams that work on different parts of the suit, so the camera's placement could directly affect their research or design. For this reason, a big part of my project was initiating contact with other branches and setting up multiple meetings to learn more about the pros and cons of the potential camera placements we are analyzing. Collaboration with the multiple teams working on the Advanced EVA Z2 Suit is absolutely necessary and these comparisons will be used as further progress is made for the overall suit design. This prototype will not be finished in time for the scheduled Z2 Suit testing, so my time was

  13. Declarative camera control for automatic cinematography

    Energy Technology Data Exchange (ETDEWEB)

    Christianson, D.B.; Anderson, S.E.; Li-wei He [Univ. of Washington, Seattle, WA (United States)] [and others

    1996-12-31

    Animations generated by interactive 3D computer graphics applications are typically portrayed either from a particular character`s point of view or from a small set of strategically-placed viewpoints. By ignoring camera placement, such applications fail to realize important storytelling capabilities that have been explored by cinematographers for many years. In this paper, we describe several of the principles of cinematography and show how they can be formalized into a declarative language, called the Declarative Camera Control Language (DCCL). We describe the application of DCCL within the context of a simple interactive video game and argue that DCCL represents cinematic knowledge at the same level of abstraction as expert directors by encoding 16 idioms from a film textbook. These idioms produce compelling animations, as demonstrated on the accompanying videotape.

  14. Relating vanishing points to catadioptric camera calibration

    Science.gov (United States)

    Duan, Wenting; Zhang, Hui; Allinson, Nigel M.

    2013-01-01

    This paper presents the analysis and derivation of the geometric relation between vanishing points and camera parameters of central catadioptric camera systems. These vanishing points correspond to the three mutually orthogonal directions of 3D real world coordinate system (i.e. X, Y and Z axes). Compared to vanishing points (VPs) in the perspective projection, the advantages of VPs under central catadioptric projection are that there are normally two vanishing points for each set of parallel lines, since lines are projected to conics in the catadioptric image plane. Also, their vanishing points are usually located inside the image frame. We show that knowledge of the VPs corresponding to XYZ axes from a single image can lead to simple derivation of both intrinsic and extrinsic parameters of the central catadioptric system. This derived novel theory is demonstrated and tested on both synthetic and real data with respect to noise sensitivity.

  15. Cervical SPECT Camera for Parathyroid Imaging

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2012-08-31

    Primary hyperparathyroidism characterized by one or more enlarged parathyroid glands has become one of the most common endocrine diseases in the world affecting about 1 per 1000 in the United States. Standard treatment is highly invasive exploratory neck surgery called Parathyroidectomy. The surgery has a notable mortality rate because of the close proximity to vital structures. The move to minimally invasive parathyroidectomy is hampered by the lack of high resolution pre-surgical imaging techniques that can accurately localize the parathyroid with respect to surrounding structures. We propose to develop a dedicated ultra-high resolution (~ 1 mm) and high sensitivity (10x conventional camera) cervical scintigraphic imaging device. It will be based on a multiple pinhole-camera SPECT system comprising a novel solid state CZT detector that offers the required performance. The overall system will be configured to fit around the neck and comfortably image a patient.

  16. Infrared camera based on a curved retina.

    Science.gov (United States)

    Dumas, Delphine; Fendler, Manuel; Berger, Frédéric; Cloix, Baptiste; Pornin, Cyrille; Baier, Nicolas; Druart, Guillaume; Primot, Jérôme; le Coarer, Etienne

    2012-02-15

    Design of miniature and light cameras requires an optical design breakthrough to achieve good optical performance. Solutions inspired by animals' eyes are the most promising. The curvature of the retina offers several advantages, such as uniform intensity and no field curvature, but this feature is not used. The work presented here is a solution to spherically bend monolithic IR detectors. Compared to state-of-the-art methods, a higher fill factor is obtained and the device fabrication process is not modified. We made an IR eye camera with a single lens and a curved IR bolometer. Images captured are well resolved and have good contrast, and the modulation transfer function shows better quality when comparing with planar systems.

  17. Time-of-Flight Microwave Camera.

    Science.gov (United States)

    Charvat, Gregory; Temme, Andrew; Feigin, Micha; Raskar, Ramesh

    2015-10-05

    Microwaves can penetrate many obstructions that are opaque at visible wavelengths, however microwave imaging is challenging due to resolution limits associated with relatively small apertures and unrecoverable "stealth" regions due to the specularity of most objects at microwave frequencies. We demonstrate a multispectral time-of-flight microwave imaging system which overcomes these challenges with a large passive aperture to improve lateral resolution, multiple illumination points with a data fusion method to reduce stealth regions, and a frequency modulated continuous wave (FMCW) receiver to achieve depth resolution. The camera captures images with a resolution of 1.5 degrees, multispectral images across the X frequency band (8 GHz-12 GHz), and a time resolution of 200 ps (6 cm optical path in free space). Images are taken of objects in free space as well as behind drywall and plywood. This architecture allows "camera-like" behavior from a microwave imaging system and is practical for imaging everyday objects in the microwave spectrum.

  18. Tomato yellow vein streak virus: relationship with Bemisia tabaci biotype B and host range Tomato yellow vein streak virus: interação com a Bemisia tabaci biótipo B e gama de hospedeiros

    Directory of Open Access Journals (Sweden)

    Ana Carolina Firmino

    2009-12-01

    Full Text Available The Tomato yellow vein streak virus (ToYVSV is a putative species of begomovirus, which was prevalent on tomato crops in São Paulo State, Brazil, until 2005. The objectives of this study were to evaluate the interaction between ToYVSV and its vector Bemisia tabaci biotype B and to identify alternative hosts for the virus. The minimum acquisition and inoculation access periods of ToYVSV by B. tabaci were 30 min and 10 min, respectively. Seventy five percent of tomato-test plants were infected when the acquisition and inoculation access periods were 24 h. The latent period of the virus in the insect was 16 h. The ToYVSV was retained by B. tabaci until 20 days after acquisition. First generation of adult whiteflies obtained from viruliferous females were virus free as shown by PCR analysis and did not transmit the virus to tomato plants. Out of 34 species of test-plants inoculated with ToYVSV only Capsicum annuum, Chenopodium amaranticolor, C. quinoa, Datura stramonium, Gomphrena globosa, Nicotiana clevelandii and N. tabacum cv. TNN were susceptible to infection. B. tabaci biotype B was able to acquire the virus from all these susceptible species, transmitting it to tomato plants.O Tomato yellow vein streak virus (ToYVSV é uma espécie putativa de begomovirus que infecta o tomateiro (Solanum lycopersicon em diversas regiões do Brasil onde se cultiva essa solanácea, sendo a espécie prevalente no estado de São Paulo até 2005. Estudou-se a interação do ToYVSV com a Bemisia tabaci biótipo B e identificaram-se hospedeiras alternativas deste vírus. Os períodos de acesso mínimo de aquisição (PAA e de inoculação (PAI foram de 30 min e 10 min, respectivamente. A porcentagem de plantas infectadas chegou até cerca de 75% após um PAA e PAI de 24 h. O período de latência do vírus no vetor foi de 16 horas. O ToYVSV foi retido pela B. tabaci até 20 dias após a aquisição do vírus. Não foi detectada transmissão do vírus para prog

  19. Small Orbital Stereo Tracking Camera Technology Development

    Science.gov (United States)

    Bryan, Tom; MacLeod, Todd; Gagliano, Larry

    2017-01-01

    Any exploration vehicle assembled or Spacecraft placed in LEO or GTO must pass through this debris cloud and survive. Large cross section, low thrust vehicles will spend more time spiraling out through the cloud and will suffer more impacts.Better knowledge of small debris will improve survival odds. Current estimated Density of debris at various orbital attitudes with notation of recent collisions and resulting spikes. Orbital Debris Tracking and Characterization has now been added to NASA Office of Chief Technologists Technology Development Roadmap in Technology Area 5 (TA5.7)[Orbital Debris Tracking and Characterization] and is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crews due to the risk of Orbital Debris damage to ISS Exploration vehicles. The Problem: Traditional orbital trackers looking for small, dim orbital derelicts and debris typically will stare at the stars and let any reflected light off the debris integrate in the imager for seconds, thus creating a streak across the image. The Solution: The Small Tracker will see Stars and other celestial objects rise through its Field of View (FOV) at the rotational rate of its orbit, but the glint off of orbital objects will move through the FOV at different rates and directions. Debris on a head-on collision course (or close) will stay in the FOV at 14 Km per sec. The Small Tracker can track at 60 frames per sec allowing up to 30 fixes before a near-miss pass. A Stereo pair of Small Trackers can provide range data within 5-7 Km for better orbit measurements.

  20. Multiple-camera tracking: UK government requirements

    Science.gov (United States)

    Hosmer, Paul

    2007-10-01

    The Imagery Library for Intelligent Detection Systems (i-LIDS) is the UK government's new standard for Video Based Detection Systems (VBDS). The standard was launched in November 2006 and evaluations against it began in July 2007. With the first four i-LIDS scenarios completed, the Home Office Scientific development Branch (HOSDB) are looking toward the future of intelligent vision in the security surveillance market by adding a fifth scenario to the standard. The fifth i-LIDS scenario will concentrate on the development, testing and evaluation of systems for the tracking of people across multiple cameras. HOSDB and the Centre for the Protection of National Infrastructure (CPNI) identified a requirement to track targets across a network of CCTV cameras using both live and post event imagery. The Detection and Vision Systems group at HOSDB were asked to determine the current state of the market and develop an in-depth Operational Requirement (OR) based on government end user requirements. Using this OR the i-LIDS team will develop a full i-LIDS scenario to aid the machine vision community in its development of multi-camera tracking systems. By defining a requirement for multi-camera tracking and building this into the i-LIDS standard the UK government will provide a widely available tool that developers can use to help them turn theory and conceptual demonstrators into front line application. This paper will briefly describe the i-LIDS project and then detail the work conducted in building the new tracking aspect of the standard.

  1. Camera Development for the Cherenkov Telescope Array

    Science.gov (United States)

    Moncada, Roberto Jose

    2017-01-01

    With the Cherenkov Telescope Array (CTA), the very-high-energy gamma-ray universe, between 30 GeV and 300 TeV, will be probed at an unprecedented resolution, allowing deeper studies of known gamma-ray emitters and the possible discovery of new ones. This exciting project could also confirm the particle nature of dark matter by looking for the gamma rays produced by self-annihilating weakly interacting massive particles (WIMPs). The telescopes will use the imaging atmospheric Cherenkov technique (IACT) to record Cherenkov photons that are produced by the gamma-ray induced extensive air shower. One telescope design features dual-mirror Schwarzschild-Couder (SC) optics that allows the light to be finely focused on the high-resolution silicon photomultipliers of the camera modules starting from a 9.5-meter primary mirror. Each camera module will consist of a focal plane module and front-end electronics, and will have four TeV Array Readout with GSa/s Sampling and Event Trigger (TARGET) chips, giving them 64 parallel input channels. The TARGET chip has a self-trigger functionality for readout that can be used in higher logic across camera modules as well as across individual telescopes, which will each have 177 camera modules. There will be two sites, one in the northern and the other in the southern hemisphere, for full sky coverage, each spanning at least one square kilometer. A prototype SC telescope is currently under construction at the Fred Lawrence Whipple Observatory in Arizona. This work was supported by the National Science Foundation's REU program through NSF award AST-1560016.

  2. Geometrical camera calibration with diffractive optical elements.

    Science.gov (United States)

    Bauer, M; Griessbach, D; Hermerschmidt, A; Krüger, S; Scheele, M; Schischmanow, A

    2008-12-08

    Traditional methods for geometrical camera calibration are based on calibration grids or single pixel illumination by collimated light. A new method for geometrical sensor calibration by means of diffractive optical elements (DOE) in connection with a laser beam equipment is presented. This method can be especially used for 2D-sensor array systems but in principle also for line scanners. (c) 2008 Optical Society of America

  3. Situational Awareness from a Low-Cost Camera System

    Science.gov (United States)

    Freudinger, Lawrence C.; Ward, David; Lesage, John

    2010-01-01

    A method gathers scene information from a low-cost camera system. Existing surveillance systems using sufficient cameras for continuous coverage of a large field necessarily generate enormous amounts of raw data. Digitizing and channeling that data to a central computer and processing it in real time is difficult when using low-cost, commercially available components. A newly developed system is located on a combined power and data wire to form a string-of-lights camera system. Each camera is accessible through this network interface using standard TCP/IP networking protocols. The cameras more closely resemble cell-phone cameras than traditional security camera systems. Processing capabilities are built directly onto the camera backplane, which helps maintain a low cost. The low power requirements of each camera allow the creation of a single imaging system comprising over 100 cameras. Each camera has built-in processing capabilities to detect events and cooperatively share this information with neighboring cameras. The location of the event is reported to the host computer in Cartesian coordinates computed from data correlation across multiple cameras. In this way, events in the field of view can present low-bandwidth information to the host rather than high-bandwidth bitmap data constantly being generated by the cameras. This approach offers greater flexibility than conventional systems, without compromising performance through using many small, low-cost cameras with overlapping fields of view. This means significant increased viewing without ignoring surveillance areas, which can occur when pan, tilt, and zoom cameras look away. Additionally, due to the sharing of a single cable for power and data, the installation costs are lower. The technology is targeted toward 3D scene extraction and automatic target tracking for military and commercial applications. Security systems and environmental/ vehicular monitoring systems are also potential applications.

  4. The Heterogeneous Treatment Effects of Speed Cameras on Road Safety

    OpenAIRE

    Li, H; Graham, DJ

    2016-01-01

    This paper analyses how the effects of fixed speed cameras on road casualties vary across sites with different characteristics and evaluates the criteria for selecting camera sites. A total of 771 camera sites and 4787 potential control sites are observed for a period of 9 years across England. Site characteristics such as road class, crash history and site length are combined into a single index, referred to as a propensity score. We first estimate the average effect at each camera site usin...

  5. Theory and applications of smart cameras

    CERN Document Server

    2016-01-01

    This book presents an overview of smart camera systems, considering practical applications but also reviewing fundamental aspects of the underlying technology.  It introduces in a tutorial style the principles of sensing and signal processing, and also describes topics such as wireless connection to the Internet of Things (IoT) which is expected to be the biggest market for smart cameras. It is an excellent guide to the fundamental of smart camera technology, and the chapters complement each other well as the authors have worked as a team under the auspice of GFP(Global Frontier Project), the largest-scale funded research in Korea.  This is the third of three books based on the Integrated Smart Sensors research project, which describe the development of innovative devices, circuits, and system-level enabling technologies.  The aim of the project was to develop common platforms on which various devices and sensors can be loaded, and to create systems offering significant improvements in information processi...

  6. Remote hardware-reconfigurable robotic camera

    Science.gov (United States)

    Arias-Estrada, Miguel; Torres-Huitzil, Cesar; Maya-Rueda, Selene E.

    2001-10-01

    In this work, a camera with integrated image processing capabilities is discussed. The camera is based on an imager coupled to an FPGA device (Field Programmable Gate Array) which contains an architecture for real-time computer vision low-level processing. The architecture can be reprogrammed remotely for application specific purposes. The system is intended for rapid modification and adaptation for inspection and recognition applications, with the flexibility of hardware and software reprogrammability. FPGA reconfiguration allows the same ease of upgrade in hardware as a software upgrade process. The camera is composed of a digital imager coupled to an FPGA device, two memory banks, and a microcontroller. The microcontroller is used for communication tasks and FPGA programming. The system implements a software architecture to handle multiple FPGA architectures in the device, and the possibility to download a software/hardware object from the host computer into its internal context memory. System advantages are: small size, low power consumption, and a library of hardware/software functionalities that can be exchanged during run time. The system has been validated with an edge detection and a motion processing architecture, which will be presented in the paper. Applications targeted are in robotics, mobile robotics, and vision based quality control.

  7. Color camera pyrometry for high explosive detonations

    Science.gov (United States)

    Densmore, John; Biss, Matthew; Homan, Barrie; McNesby, Kevin

    2011-06-01

    Temperature measurements of high-explosive and combustion processes are difficult because of the speed and environment of the events. We have characterized and calibrated a digital high-speed color camera that may be used as an optical pyrometer to overcome these challenges. The camera provides both high temporal and spatial resolution. The color filter array of the sensor uses three color filters to measure the spectral distribution of the imaged light. A two-color ratio method is used to calculate a temperature using the color filter array raw image data and a gray-body assumption. If the raw image data is not available, temperatures may be calculated from processed images or movies depending on proper analysis of the digital color imaging pipeline. We analyze three transformations within the pipeline (demosaicing, white balance, and gamma-correction) to determine their effect on the calculated temperature. Using this technique with a Vision Research Phantom color camera, we have measured the temperature of exploded C-4 charges. The surface temperature of the resulting fireball rapidly increases after detonation and then decayed to a constant value of approximately 1980 K. Processed images indicates that the temperature remains constant until the light intensity decreased below the background value.

  8. A single pixel camera video ophthalmoscope

    Science.gov (United States)

    Lochocki, B.; Gambin, A.; Manzanera, S.; Irles, E.; Tajahuerce, E.; Lancis, J.; Artal, P.

    2017-02-01

    There are several ophthalmic devices to image the retina, from fundus cameras capable to image the whole fundus to scanning ophthalmoscopes with photoreceptor resolution. Unfortunately, these devices are prone to a variety of ocular conditions like defocus and media opacities, which usually degrade the quality of the image. Here, we demonstrate a novel approach to image the retina in real-time using a single pixel camera, which has the potential to circumvent those optical restrictions. The imaging procedure is as follows: a set of spatially coded patterns is projected rapidly onto the retina using a digital micro mirror device. At the same time, the inner product's intensity is measured for each pattern with a photomultiplier module. Subsequently, an image of the retina is reconstructed computationally. Obtained image resolution is up to 128 x 128 px with a varying real-time video framerate up to 11 fps. Experimental results obtained in an artificial eye confirm the tolerance against defocus compared to a conventional multi-pixel array based system. Furthermore, the use of a multiplexed illumination offers a SNR improvement leading to a lower illumination of the eye and hence an increase in patient's comfort. In addition, the proposed system could enable imaging in wavelength ranges where cameras are not available.

  9. Toward standardising gamma camera quality control procedures

    Science.gov (United States)

    Alkhorayef, M. A.; Alnaaimi, M. A.; Alduaij, M. A.; Mohamed, M. O.; Ibahim, S. Y.; Alkandari, F. A.; Bradley, D. A.

    2015-11-01

    Attaining high standards of efficiency and reliability in the practice of nuclear medicine requires appropriate quality control (QC) programs. For instance, the regular evaluation and comparison of extrinsic and intrinsic flood-field uniformity enables the quick correction of many gamma camera problems. Whereas QC tests for uniformity are usually performed by exposing the gamma camera crystal to a uniform flux of gamma radiation from a source of known activity, such protocols can vary significantly. Thus, there is a need for optimization and standardization, in part to allow direct comparison between gamma cameras from different vendors. In the present study, intrinsic uniformity was examined as a function of source distance, source activity, source volume and number of counts. The extrinsic uniformity and spatial resolution were also examined. Proper standard QC procedures need to be implemented because of the continual development of nuclear medicine imaging technology and the rapid expansion and increasing complexity of hybrid imaging system data. The present work seeks to promote a set of standard testing procedures to contribute to the delivery of safe and effective nuclear medicine services.

  10. Camera Network Coverage Improving by Particle Swarm Optimization

    NARCIS (Netherlands)

    Xu, Y.C.; Lei, B.; Hendriks, E.A.

    2011-01-01

    This paper studies how to improve the field of view (FOV) coverage of a camera network. We focus on a special but practical scenario where the cameras are randomly scattered in a wide area and each camera may adjust its orientation but cannot move in any direction. We propose a particle swarm

  11. 16 CFR 3.45 - In camera orders.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false In camera orders. 3.45 Section 3.45... PRACTICE FOR ADJUDICATIVE PROCEEDINGS Hearings § 3.45 In camera orders. (a) Definition. Except as hereinafter provided, material made subject to an in camera order will be kept confidential and not placed on...

  12. 15 CFR 743.3 - Thermal imaging camera reporting.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Thermal imaging camera reporting. 743... REPORTING § 743.3 Thermal imaging camera reporting. (a) General requirement. Exports of thermal imaging cameras must be reported to BIS as provided in this section. (b) Transactions to be reported. Exports that...

  13. 39 CFR 3001.31a - In camera orders.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false In camera orders. 3001.31a Section 3001.31a Postal... Applicability § 3001.31a In camera orders. (a) Definition. Except as hereinafter provided, documents and testimony made subject to in camera orders are not made a part of the public record, but are kept...

  14. 21 CFR 878.4160 - Surgical camera and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Surgical camera and accessories. 878.4160 Section... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4160 Surgical camera and accessories. (a) Identification. A surgical camera and accessories is a device intended to be used...

  15. 49 CFR 511.45 - In camera materials.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false In camera materials. 511.45 Section 511.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ADJUDICATIVE PROCEDURES Hearings § 511.45 In camera materials. (a) Definition. In camera materials are documents, testimony, or other data which by order of the Presiding...

  16. Speed cameras : how they work and what effect they have.

    NARCIS (Netherlands)

    2011-01-01

    Much research has been carried out into the effects of speed cameras, and the research shows consistently positive results. International review studies report that speed cameras produce a reduction of approximately 20% in personal injury crashes on road sections where cameras are used. In the

  17. 21 CFR 892.1100 - Scintillation (gamma) camera.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scintillation (gamma) camera. 892.1100 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1100 Scintillation (gamma) camera. (a) Identification. A scintillation (gamma) camera is a device intended to image the distribution of radionuclides in...

  18. A system to enrich for primitive streak-derivatives, definitive endoderm and mesoderm, from pluripotent cells in culture.

    Science.gov (United States)

    Vassilieva, Svetlana; Goh, Hwee Ngee; Lau, Kevin X; Hughes, James N; Familari, Mary; Rathjen, Peter D; Rathjen, Joy

    2012-01-01

    Two lineages of endoderm develop during mammalian embryogenesis, the primitive endoderm in the pre-implantation blastocyst and the definitive endoderm at gastrulation. This complexity of endoderm cell populations is mirrored during pluripotent cell differentiation in vitro and has hindered the identification and purification of the definitive endoderm for use as a substrate for further differentiation. The aggregation and differentiation of early primitive ectoderm-like (EPL) cells, resulting in the formation of EPL-cell derived embryoid bodies (EPLEBs), is a model of gastrulation that progresses through the sequential formation of primitive streak-like intermediates to nascent mesoderm and more differentiated mesoderm populations. EPL cell-derived EBs have been further analysed for the formation of definitive endoderm by detailed morphological studies, gene expression and a protein uptake assay. In comparison to embryoid bodies derived from ES cells, which form primitive and definitive endoderm, the endoderm compartment of embryoid bodies formed from EPL cells was comprised almost exclusively of definitive endoderm. Definitive endoderm was defined as a population of squamous cells that expressed Sox17, CXCR4 and Trh, which formed without the prior formation of primitive endoderm and was unable to endocytose horseradish peroxidase from the medium. Definitive endoderm formed in EPLEBs provides a substrate for further differentiation into specific endoderm lineages; these lineages can be used as research tools for understanding the mechanisms controlling lineage establishment and the nature of the transient intermediates formed. The similarity between mouse EPL cells and human ES cells suggests EPLEBs can be used as a model system for the development of technologies to enrich for the formation of human ES cell-derived definitive endoderm in the future.

  19. Promoters for pregenomic RNA of banana streak badnavirus are active for transgene expression in monocot and dicot plants.

    Science.gov (United States)

    Schenk, P M; Remans, T; Sági, L; Elliott, A R; Dietzgen, R G; Swennen, R; Ebert, P R; Grof, C P; Manners, J M

    2001-10-01

    Two putative promoters from Australian banana streak badnavirus (BSV) isolates were analysed for activity in different plant species. In transient expression systems the My (2105 bp) and Cv (1322 bp) fragments were both shown to have promoter activity in a wide range of plant species including monocots (maize, barley, banana, millet, wheat, sorghum), dicots (tobacco, canola, sunflower, Nicotiana benthamiana, tipu tree), gymnosperm (Pinus radiata) and fern (Nephrolepis cordifolia). Evaluation of the My and Cv promoters in transgenic sugarcane, banana and tobacco plants demonstrated that these promoters could drive high-level expression of either the green fluorescent protein (GFP) or the beta-glucuronidase (GUS) reporter gene (uidA) in vegetative plant cells. In transgenic sugarcane plants harbouring the Cv promoter, GFP expression levels were comparable or higher (up to 1.06% of total soluble leaf protein as GFP) than those of plants containing the maize ubiquitin promoter (up to 0.34% of total soluble leaf protein). GUS activities in transgenic in vitro-grown banana plants containing the My promoter were up to seven-fold stronger in leaf tissue and up to four-fold stronger in root and corm tissue than in plants harbouring the maize ubiquitin promoter. The Cv promoter showed activities that were similar to the maize ubiquitin promoter in in vitro-grown banana plants, but was significantly reduced in larger glasshouse-grown plants. In transgenic in vitro-grown tobacco plants, the My promoter reached activities close to those of the 35S promoter of cauliflower mosaic virus (CaMV), while the Cv promoter was about half as active as the CaMV 35S promoter. The BSV promoters for pregenomic RNA represent useful tools for the high-level expression of foreign genes in transgenic monocots.

  20. Foraging spots of streaked shearwaters in relation to ocean surface currents as identified using their drift movements

    Science.gov (United States)

    Yoda, Ken; Shiomi, Kozue; Sato, Katsufumi

    2014-03-01

    Ocean currents are in continuous motion and strongly influence oceanic ecosystems. In situ observation of currents is of primary importance for understanding how marine animals respond to ocean surface currents at various scales and for realizing effective ecosystem-based management and realistic oceanographic modelling. We developed a new method for obtaining in situ current measurements by using seabirds as Lagrangian current sensors akin to drifting buoys. We deployed high-resolution global positioning system (GPS) loggers on streaked shearwaters (Calonectris leucomelas) foraging in the Oyashio-Tsugaru Warm Current confluence in Japan, which is one of the most productive oceans in the world. The seabirds repeatedly performed foraging trips, including searching for prey and resting on the sea surface, over several hundred kilometres. The seabirds spent half of their time resting on the water surface and tended to be passive drifters. We inferred that the drift movements of C. leucomelas provided a direct and detailed description of the ocean surface currents, because currents deduced from their drift movements were in good agreement with ocean surface currents derived from in situ and satellite data. In addition, we extracted details of shearwaters’ intense searching flights associated with feeding (i.e. foraging spots) from GPS tracks. C. leucomelas did not forage at the core of anticyclonic eddies; rather, they used the boundary areas between eddies and the edge of eddies where primary productivity and prey density are thought to be high. Our study demonstrated that animal-borne GPS data can provide a detailed and cost-efficient tool for observing ocean surface currents and can reveal the ways in which marine animals respond to these currents at a fine scale.

  1. Hairpin RNA derived from viral NIa gene confers immunity to wheat streak mosaic virus infection in transgenic wheat plants.

    Science.gov (United States)

    Fahim, Muhammad; Ayala-Navarrete, Ligia; Millar, Anthony A; Larkin, Philip J

    2010-09-01

    Wheat streak mosaic virus (WSMV), vectored by Wheat curl mite, has been of great economic importance in the Great Plains of the United States and Canada. Recently, the virus has been identified in Australia, where it has spread quickly to all major wheat growing areas. The difficulties in finding adequate natural resistance in wheat prompted us to develop transgenic resistance based on RNA interference (RNAi). An RNAi construct was designed to target the nuclear inclusion protein 'a' (NIa) gene of WSMV. Wheat was stably cotransformed with two plasmids: pStargate-NIa expressing hairpin RNA (hpRNA) including WSMV sequence and pCMneoSTLS2 with the nptII selectable marker. When T(1) progeny were assayed against WSMV, ten of sixteen families showed complete resistance in transgenic segregants. The resistance was classified as immunity by four criteria: no disease symptoms were produced; ELISA readings were as in uninoculated plants; viral sequences could not be detected by RT-PCR from leaf extracts; and leaf extracts failed to give infections in susceptible plants when used in test-inoculation experiments. Southern blot hybridization analysis indicated hpRNA transgene integrated into the wheat genome. Moreover, accumulation of small RNAs derived from the hpRNA transgene sequence positively correlated with immunity. We also showed that the selectable marker gene nptII segregated independently of the hpRNA transgene in some transgenics, and therefore demonstrated that it is possible using these techniques, to produce marker-free WSMV immune transgenic plants. This is the first report of immunity in wheat to WSMV using a spliceable intron hpRNA strategy.

  2. Cholesterol crystallization in human atherosclerosis is triggered in smooth muscle cells during the transition from fatty streak to fibroatheroma.

    Science.gov (United States)

    Ho-Tin-Noé, Benoît; Vo, Sophie; Bayles, Richard; Ferrière, Stephen; Ladjal, Hayette; Toumi, Sondes; Deschildre, Catherine; Ollivier, Véronique; Michel, Jean-Baptiste

    2017-04-01

    Recent studies have shown that in addition to being major constituents of the atheromatous core, solid cholesterol crystals (CCs) promote atherosclerotic lesion development and rupture by causing mechanical damage and exerting cytotoxic and pro-inflammatory effects. These findings suggest that targeting CCs might represent a therapeutic strategy for plaque stabilization. However, little is known about how cholesterol crystallization is initiated in human atherothrombotic disease. Here, we investigated these mechanisms. We performed a thorough immunohistological analysis of non-embedded, minimally processed human aortic tissues, combining polarized light and fluorescence microscopy. We found that CC formation was initiated during the fatty streak to fibroatheroma transition in tight association with the death of intralesional smooth muscle cells (SMCs). Cholesterol-loaded human SMCs were capable of producing CCs in vitro, a process that was enhanced by type I collagen and by inhibition of autophagy and cholesterol esterification. The fibrous transition, which was characterized by increased type I collagen expression, was associated with changes in the expression of autophagy and cholesterol flux-related genes, including a decrease in the autophagic adapter p62 and an increase in the cholesterol intracellular transporter Niemann-Pick C1. Collagen was identified as a potent inducer of these changes in SMCs. Collagen-induced changes in cholesterol metabolism and autophagy flux in smooth muscle foam cells at the fibrolipid transition likely contribute to initiate cholesterol crystallization in human atherosclerosis. Also, our data are in support of a protective role of autophagy against CC formation. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  3. A system to enrich for primitive streak-derivatives, definitive endoderm and mesoderm, from pluripotent cells in culture.

    Directory of Open Access Journals (Sweden)

    Svetlana Vassilieva

    Full Text Available Two lineages of endoderm develop during mammalian embryogenesis, the primitive endoderm in the pre-implantation blastocyst and the definitive endoderm at gastrulation. This complexity of endoderm cell populations is mirrored during pluripotent cell differentiation in vitro and has hindered the identification and purification of the definitive endoderm for use as a substrate for further differentiation. The aggregation and differentiation of early primitive ectoderm-like (EPL cells, resulting in the formation of EPL-cell derived embryoid bodies (EPLEBs, is a model of gastrulation that progresses through the sequential formation of primitive streak-like intermediates to nascent mesoderm and more differentiated mesoderm populations. EPL cell-derived EBs have been further analysed for the formation of definitive endoderm by detailed morphological studies, gene expression and a protein uptake assay. In comparison to embryoid bodies derived from ES cells, which form primitive and definitive endoderm, the endoderm compartment of embryoid bodies formed from EPL cells was comprised almost exclusively of definitive endoderm. Definitive endoderm was defined as a population of squamous cells that expressed Sox17, CXCR4 and Trh, which formed without the prior formation of primitive endoderm and was unable to endocytose horseradish peroxidase from the medium. Definitive endoderm formed in EPLEBs provides a substrate for further differentiation into specific endoderm lineages; these lineages can be used as research tools for understanding the mechanisms controlling lineage establishment and the nature of the transient intermediates formed. The similarity between mouse EPL cells and human ES cells suggests EPLEBs can be used as a model system for the development of technologies to enrich for the formation of human ES cell-derived definitive endoderm in the future.

  4. Methods for identification of images acquired with digital cameras

    Science.gov (United States)

    Geradts, Zeno J.; Bijhold, Jurrien; Kieft, Martijn; Kurosawa, Kenji; Kuroki, Kenro; Saitoh, Naoki

    2001-02-01

    From the court we were asked whether it is possible to determine if an image has been made with a specific digital camera. This question has to be answered in child pornography cases, where evidence is needed that a certain picture has been made with a specific camera. We have looked into different methods of examining the cameras to determine if a specific image has been made with a camera: defects in CCDs, file formats that are used, noise introduced by the pixel arrays and watermarking in images used by the camera manufacturer.

  5. Pile volume measurement by range imaging camera in indoor environment

    Directory of Open Access Journals (Sweden)

    C. Altuntas

    2014-06-01

    Full Text Available Range imaging (RIM camera is recent technology in 3D location measurement. The new study areas have been emerged in measurement and data processing together with RIM camera. It has low-cost and fast measurement technique compared to the current measurement techniques. However its measurement accuracy varies according to effects resulting from the device and the environment. The direct sunlight is affect measurement accuracy of the camera. Thus, RIM camera should be used for indoor measurement. In this study gravel pile volume was measured by SwissRanger SR4000 camera. The measured volume is acquired as different 8.13% from the known.

  6. Presence capture cameras - a new challenge to the image quality

    Science.gov (United States)

    Peltoketo, Veli-Tapani

    2016-04-01

    Commercial presence capture cameras are coming to the markets and a new era of visual entertainment starts to get its shape. Since the true presence capturing is still a very new technology, the real technical solutions are just passed a prototyping phase and they vary a lot. Presence capture cameras have still the same quality issues to tackle as previous phases of digital imaging but also numerous new ones. This work concentrates to the quality challenges of presence capture cameras. A camera system which can record 3D audio-visual reality as it is has to have several camera modules, several microphones and especially technology which can synchronize output of several sources to a seamless and smooth virtual reality experience. Several traditional quality features are still valid in presence capture cameras. Features like color fidelity, noise removal, resolution and dynamic range create the base of virtual reality stream quality. However, co-operation of several cameras brings a new dimension for these quality factors. Also new quality features can be validated. For example, how the camera streams should be stitched together with 3D experience without noticeable errors and how to validate the stitching? The work describes quality factors which are still valid in the presence capture cameras and defines the importance of those. Moreover, new challenges of presence capture cameras are investigated in image and video quality point of view. The work contains considerations how well current measurement methods can be used in presence capture cameras.

  7. MEDIUM-FORMAT CAMERAS AND THEIR USE IN TOPOGRAPHIC MAPPING

    Directory of Open Access Journals (Sweden)

    J. Höhle

    2012-07-01

    Full Text Available Based on practical experiences with large-format aerial cameras the impact of new medium-format digital cameras on topographic mapping tasks is discussed. Two new medium-format cameras are investigated with respect to elevation accuracy, area coverage and image quality. The produced graphs and tables show the potential of these cameras for general mapping tasks. Special attention is given to the image quality of the selected cameras. Applications for the medium-format cameras are discussed. The necessary tools for selected applications are described. The impact of sensors for georeferencing, multi-spectral images, and new matching algo-rithms is also dealt with. Practical investigations are carried out for the production of digital elevation models. A comparison with large-format frame cameras is carried out. It is concluded that the medium-format cameras have a potential for mapping of smaller areas and will be used in future in true orthoimage production, corridor mapping, and updating of maps. Their small dimensions and low weight allow installation in small airplanes, helicopters, and high-end UAVs. The two investigated medium-format cameras are low-cost alternatives for standard mapping tasks and special applications. The detection of changes in topographic databases and DTMs can be carried out by means of those medium-format cameras which can image the same area in four bands of the visible and invisible spectrum of light. Medium-format cameras will play an important role in future mapping tasks.

  8. High-dimensional camera shake removal with given depth map.

    Science.gov (United States)

    Yue, Tao; Suo, Jinli; Dai, Qionghai

    2014-06-01

    Camera motion blur is drastically nonuniform for large depth-range scenes, and the nonuniformity caused by camera translation is depth dependent but not the case for camera rotations. To restore the blurry images of large-depth-range scenes deteriorated by arbitrary camera motion, we build an image blur model considering 6-degrees of freedom (DoF) of camera motion with a given scene depth map. To make this 6D depth-aware model tractable, we propose a novel parametrization strategy to reduce the number of variables and an effective method to estimate high-dimensional camera motion as well. The number of variables is reduced by temporal sampling motion function, which describes the 6-DoF camera motion by sampling the camera trajectory uniformly in time domain. To effectively estimate the high-dimensional camera motion parameters, we construct the probabilistic motion density function (PMDF) to describe the probability distribution of camera poses during exposure, and apply it as a unified constraint to guide the convergence of the iterative deblurring algorithm. Specifically, PMDF is computed through a back projection from 2D local blur kernels to 6D camera motion parameter space and robust voting. We conduct a series of experiments on both synthetic and real captured data, and validate that our method achieves better performance than existing uniform methods and nonuniform methods on large-depth-range scenes.

  9. Initial laboratory evaluation of color video cameras: Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Terry, P.L.

    1993-07-01

    Sandia National Laboratories has considerable experience with monochrome video cameras used in alarm assessment video systems. Most of these systems, used for perimeter protection, were designed to classify rather than to identify intruders. The monochrome cameras were selected over color cameras because they have greater sensitivity and resolution. There is a growing interest in the identification function of security video systems for both access control and insider protection. Because color camera technology is rapidly changing and because color information is useful for identification purposes, Sandia National Laboratories has established an on-going program to evaluate the newest color solid-state cameras. Phase One of the Sandia program resulted in the SAND91-2579/1 report titled: Initial Laboratory Evaluation of Color Video Cameras. The report briefly discusses imager chips, color cameras, and monitors, describes the camera selection, details traditional test parameters and procedures, and gives the results reached by evaluating 12 cameras. Here, in Phase Two of the report, we tested 6 additional cameras using traditional methods. In addition, all 18 cameras were tested by newly developed methods. This Phase 2 report details those newly developed test parameters and procedures, and evaluates the results.

  10. Optical designs for the Mars '03 rover cameras

    Science.gov (United States)

    Smith, Gregory H.; Hagerott, Edward C.; Scherr, Lawrence M.; Herkenhoff, Kenneth E.; Bell, James F.

    2001-12-01

    In 2003, NASA is planning to send two robotic rover vehicles to explore the surface of Mars. The spacecraft will land on airbags in different, carefully chosen locations. The search for evidence indicating conditions favorable for past or present life will be a high priority. Each rover will carry a total of ten cameras of five various types. There will be a stereo pair of color panoramic cameras, a stereo pair of wide- field navigation cameras, one close-up camera on a movable arm, two stereo pairs of fisheye cameras for hazard avoidance, and one Sun sensor camera. This paper discusses the lenses for these cameras. Included are the specifications, design approaches, expected optical performances, prescriptions, and tolerances.

  11. Calibration of asynchronous smart phone cameras from moving objects

    Science.gov (United States)

    Hagen, Oksana; Istenič, Klemen; Bharti, Vibhav; Dhali, Maruf Ahmed; Barmaimon, Daniel; Houssineau, Jérémie; Clark, Daniel

    2015-04-01

    Calibrating multiple cameras is a fundamental prerequisite for many Computer Vision applications. Typically this involves using a pair of identical synchronized industrial or high-end consumer cameras. This paper considers an application on a pair of low-cost portable cameras with different parameters that are found in smart phones. This paper addresses the issues of acquisition, detection of moving objects, dynamic camera registration and tracking of arbitrary number of targets. The acquisition of data is performed using two standard smart phone cameras and later processed using detections of moving objects in the scene. The registration of cameras onto the same world reference frame is performed using a recently developed method for camera calibration using a disparity space parameterisation and the single-cluster PHD filter.

  12. Tracking camera control in endoscopic dacryocystorhinostomy surgery.

    Science.gov (United States)

    Wawrzynski, J R; Smith, P; Tang, L; Hoare, T; Caputo, S; Siddiqui, A A; Tsatsos, M; Saleh, G M

    2015-12-01

    Poor camera control during endoscopic dacryocystorhinostomy (EnDCR) surgery can cause inadequate visualisation of the anatomy and suboptimal surgical outcomes. This study investigates the feasibility of using computer vision tracking in EnDCR surgery as a potential formative feedback tool for the quality of endoscope control. A prospective cohort analysis was undertaken comparing junior versus senior surgeons performing routine EnDCR surgery. Computer vision tracking was applied to endoscopic video footage of the surgery: Total number of movements, camera path length in pixels and surgical time were determined for each procedure. A Mann-Whitney U-test was used to test for a significant difference between juniors and seniors (P theatre. Ten junior surgeons (100 completed procedures). Total number of movements of the endoscope per procedure. Path length of the endoscope per procedure. Twenty videos, 10 from junior surgeons and 10 from senior surgeons were analysed. Feasibility of our tracking system was demonstrated. Mean camera path lengths were significantly different at 119,329px (juniors) versus 43,697px (seniors), P ≪ 0.05. The mean number of movements was significantly different at 9134 (juniors) versus 3690 (seniors), P ≪ 0.05. These quantifiable differences demonstrate construct validity for computer vision endoscope tracking as a measure of surgical experience. Computer vision tracking is a potentially useful structured and objective feedback tool to assist trainees in improving endoscope control. It enables juniors to examine how their pattern of endoscope control differs from that of seniors, focusing in particular on sections where they are most divergent. © 2015 John Wiley & Sons Ltd.

  13. Use of cameras for monitoring visibility impairment

    Science.gov (United States)

    Malm, William; Cismoski, Scott; Prenni, Anthony; Peters, Melanie

    2018-02-01

    Webcams and automated, color photography cameras have been routinely operated in many U.S. national parks and other federal lands as far back as 1988, with a general goal of meeting interpretive needs within the public lands system and communicating effects of haze on scenic vistas to the general public, policy makers, and scientists. Additionally, it would be desirable to extract quantifiable information from these images to document how visibility conditions change over time and space and to further reflect the effects of haze on a scene, in the form of atmospheric extinction, independent of changing lighting conditions due to time of day, year, or cloud cover. Many studies have demonstrated a link between image indexes and visual range or extinction in urban settings where visibility is significantly degraded and where scenes tend to be gray and devoid of color. In relatively clean, clear atmospheric conditions, clouds and lighting conditions can sometimes affect the image radiance field as much or more than the effects of haze. In addition, over the course of many years, cameras have been replaced many times as technology improved or older systems wore out, and therefore camera image pixel density has changed dramatically. It is shown that gradient operators are very sensitive to image resolution while contrast indexes are not. Furthermore, temporal averaging and time of day restrictions allow for developing quantitative relationships between atmospheric extinction and contrast-type indexes even when image resolution has varied over time. Temporal averaging effectively removes the variability of visibility indexes associated with changing cloud cover and weather conditions, and changes in lighting conditions resulting from sun angle effects are best compensated for by restricting averaging to only certain times of the day.

  14. Video inpainting under constrained camera motion.

    Science.gov (United States)

    Patwardhan, Kedar A; Sapiro, Guillermo; Bertalmío, Marcelo

    2007-02-01

    A framework for inpainting missing parts of a video sequence recorded with a moving or stationary camera is presented in this work. The region to be inpainted is general: it may be still or moving, in the background or in the foreground, it may occlude one object and be occluded by some other object. The algorithm consists of a simple preprocessing stage and two steps of video inpainting. In the preprocessing stage, we roughly segment each frame into foreground and background. We use this segmentation to build three image mosaics that help to produce time consistent results and also improve the performance of the algorithm by reducing the search space. In the first video inpainting step, we reconstruct moving objects in the foreground that are "occluded" by the region to be inpainted. To this end, we fill the gap as much as possible by copying information from the moving foreground in other frames, using a priority-based scheme. In the second step, we inpaint the remaining hole with the background. To accomplish this, we first align the frames and directly copy when possible. The remaining pixels are filled in by extending spatial texture synthesis techniques to the spatiotemporal domain. The proposed framework has several advantages over state-of-the-art algorithms that deal with similar types of data and constraints. It permits some camera motion, is simple to implement, fast, does not require statistical models of background nor foreground, works well in the presence of rich and cluttered backgrounds, and the results show that there is no visible blurring or motion artifacts. A number of real examples taken with a consumer hand-held camera are shown supporting these findings.

  15. Thermal imaging cameras characteristics and performance

    CERN Document Server

    Williams, Thomas

    2009-01-01

    The ability to see through smoke and mist and the ability to use the variances in temperature to differentiate between targets and their backgrounds are invaluable in military applications and have become major motivators for the further development of thermal imagers. As the potential of thermal imaging is more clearly understood and the cost decreases, the number of industrial and civil applications being exploited is growing quickly. In order to evaluate the suitability of particular thermal imaging cameras for particular applications, it is important to have the means to specify and measur

  16. Computational cameras for moving iris recognition

    Science.gov (United States)

    McCloskey, Scott; Venkatesha, Sharath

    2015-05-01

    Iris-based biometric identification is increasingly used for facility access and other security applications. Like all methods that exploit visual information, however, iris systems are limited by the quality of captured images. Optical defocus due to a small depth of field (DOF) is one such challenge, as is the acquisition of sharply-focused iris images from subjects in motion. This manuscript describes the application of computational motion-deblurring cameras to the problem of moving iris capture, from the underlying theory to system considerations and performance data.

  17. Camera calibration: estimation, validation and software

    OpenAIRE

    Personnaz, Matthieu; Horaud, Radu

    2002-01-01

    The software tele2 3.1 allows, in particular, to measure the intrinsic parameters of a camera. Nevertheless, a single measure do not allow to characterize the distribution associated to a parameter. Moreover, if the way to obtain measures is incorrect, these measures may be outliers.Also, this document is made up of a method to measure the intrinsic parameters thanks to the software tele2 3.1, and to quantify the quality of the obtained values.An analysis of the experimental data is provided ...

  18. Overview of SWIR detectors, cameras, and applications

    Science.gov (United States)

    Hansen, Marc P.; Malchow, Douglas S.

    2008-03-01

    Imaging in the short wave infrared (SWIR) can bring useful contrast to situations and applications where visible or thermal imaging cameras are ineffective. This paper will define the short wave infrared technology and discuss developing imaging applications; then describe newly available 2-D (area) and 1-D (linear) arrays made with indium-gallium-arsenide (InGaAs), while presenting the wide range of applications with images and videos. Applications mentioned will be web inspection of continuous processes such as high temperature manufacturing processes, agricultural raw material cleaning and sorting, plastics recycling of automotive and consumer products, and a growing biological imaging technique, Spectral-Domain Optical Coherence Tomography.

  19. Digital camera resolution and proximal caries detection.

    Science.gov (United States)

    Prapayasatok, S; Janhom, A; Verochana, K; Pramojanee, S

    2006-07-01

    To evaluate the diagnostic accuracy of proximal caries detection from digitized film images captured by a digital camera at different resolution settings. Twenty-five periapical radiographs of 50 premolar and 25 molar teeth were photographed using a digital camera, Sony Cyber-shot, DSC-S75 at three different resolution settings: 640 x 480, 1280 x 960 and 1600 x 1200. Seventy-five digital images were transferred to a computer, saved and opened using ACDSee software. In addition, a PowerPoint slide was made from each digital image. Five observers scored three groups of images (the films, the displayed 1:1 digital images on the ACDSee software, and the PowerPoint slides) for the existence of proximal caries using a 5-point confidence scale, and the depth of caries on a 4-point scale. Ground sections of the teeth were used as the gold standard. Az values under the receiver operating characteristic (ROC) curve of each group of images and at different resolutions were compared using the Friedman and Wilcoxon signed rank tests. Mean different values between the lesions' depth interpreted by the observers and that of the gold standard were analysed. Films showed the highest Az values. Only the 1280 x 960 images on the ACDSee software showed no significant difference of the Az value from the films (P=0.28). The digital images from three resolution settings on the PowerPoint slides showed no significant differences, either among each other or between them and the films. For caries depth, the 1280 x 960 images showed lower values of mean difference in enamel lesions compared with the other two resolution groups. This study showed that in order to digitize conventional films, it was not necessary to use the highest camera resolution setting to achieve high diagnostic accuracy for proximal caries detection. The 1280 x 960 resolution setting of the digital camera demonstrated comparable diagnostic accuracy with film and was adequate for digitizing radiographs for caries

  20. Wheat streak mosaic virus Coat Protein Deletion Mutants Elicit More Severe Symptoms Than Wild-Type Virus in Multiple Cereal Hosts.

    Science.gov (United States)

    Tatineni, Satyanarayana; Elowsky, Christian; Graybosch, Robert A

    2017-12-01

    Previously, we reported that coat protein (CP) of Wheat streak mosaic virus (WSMV) (genus Tritimovirus, family Potyviridae) tolerates deletion of amino acids 36 to 84 for efficient systemic infection of wheat. In this study, we demonstrated that WSMV mutants with deletion of CP amino acids 58 to 84 but not of 36 to 57 induced severe chlorotic streaks and spots, followed by acute chlorosis in wheat, maize, barley, and rye compared with mild to moderate chlorotic streaks and mosaic symptoms by wild-type virus. Deletion of CP amino acids 58 to 84 from the WSMV genome accelerated cell-to-cell movement, with increased accumulation of genomic RNAs and CP, compared with the wild-type virus. Microscopic examination of wheat tissues infected by green fluorescent protein-tagged mutants revealed that infection by mutants lacking CP amino acids 58 to 84 caused degradation of chloroplasts, resulting in acute macroscopic chlorosis. The profile of CP-specific proteins was altered in wheat infected by mutants causing acute chlorosis, compared with mutants eliciting wild-type symptoms. All deletion mutants accumulated CP-specific major protein similarly to that in wild-type virus; however, mutants that elicit acute chlorosis failed to accumulate a 31-kDa minor protein compared with wild-type virus or mutants lacking amino acids 36 to 57. Taken together, these data suggest that deletion of CP amino acids 58 to 84 from the WSMV genome enhanced accumulation of CP and genomic RNA, altered CP-specific protein profiles, and caused severe symptom phenotypes in multiple cereal hosts.

  1. Exploiting the combination of natural and genetically engineered resistance to cassava mosaic and cassava brown streak viruses impacting cassava production in Africa.

    Directory of Open Access Journals (Sweden)

    Hervé Vanderschuren

    Full Text Available Cassava brown streak disease (CBSD and cassava mosaic disease (CMD are currently two major viral diseases that severely reduce cassava production in large areas of Sub-Saharan Africa. Natural resistance has so far only been reported for CMD in cassava. CBSD is caused by two virus species, Cassava brown streak virus (CBSV and Ugandan cassava brown streak virus (UCBSV. A sequence of the CBSV coat protein (CP highly conserved between the two virus species was used to demonstrate that a CBSV-CP hairpin construct sufficed to generate immunity against both viral species in the cassava model cultivar (cv. 60444. Most of the transgenic lines showed high levels of resistance under increasing viral loads using a stringent top-grafting method of inoculation. No viral replication was observed in the resistant transgenic lines and they remained free of typical CBSD root symptoms 7 month post-infection. To generate transgenic cassava lines combining resistance to both CBSD and CMD the hairpin construct was transferred to a CMD-resistant farmer-preferred Nigerian landrace TME 7 (Oko-Iyawo. An adapted protocol allowed the efficient Agrobacterium-based transformation of TME 7 and the regeneration of transgenic lines with high levels of CBSV-CP hairpin-derived small RNAs. All transgenic TME 7 lines were immune to both CBSV and UCBSV infections. Further evaluation of the transgenic TME 7 lines revealed that CBSD resistance was maintained when plants were co-inoculated with East African cassava mosaic virus (EACMV, a geminivirus causing CMD. The innovative combination of natural and engineered virus resistance in farmer-preferred landraces will be particularly important to reducing the increasing impact of cassava viral diseases in Africa.

  2. Homoeologous recombination-based transfer and molecular cytogenetic mapping of a wheat streak mosaic virus and Triticum mosaic virus resistance gene Wsm3 from Thinopyrum intermedium to wheat.

    Science.gov (United States)

    Danilova, Tatiana V; Zhang, Guorong; Liu, Wenxuan; Friebe, Bernd; Gill, Bikram S

    2017-03-01

    Here, we report the production of a wheat- Thinopyrum intermedium recombinant stock conferring resistance to wheat streak mosaic virus and Triticum mosaic virus. Wheat streak mosaic caused by the wheat streak mosaic virus (WSMV) is an important disease of bread wheat (Triticum aestivum) worldwide. To date, only three genes conferring resistance to WSMV have been named and two, Wsm1 and Wsm3, were derived from the distantly related wild relative Thinopyrum intermedium. Wsm3 is only available in the form of a compensating wheat-Th. intermedium whole-arm Robertsonian translocation T7BS·7S#3L. Whole-arm alien transfers usually suffer from linkage drag, which prevents their use in cultivar improvement. Here, we report ph1b-induced homoeologous recombination to shorten the Th. intermedium segment and recover a recombinant chromosome consisting of the short arm of wheat chromosome 7B, part of the long arm of 7B, and the distal 43% of the long arm derived from the Th. intermedium chromosome arm 7S#3L. The recombinant chromosome T7BS·7BL-7S#3L confers resistance to WSMV at 18 and 24 °C and also confers resistance to Triticum mosaic virus, but only at 18 °C. Wsm3 is the only gene conferring resistance to WSMV at a high temperature level of 24 °C. We also developed a user-friendly molecular marker that will allow to monitor the transfer of Wsm3 in breeding programs. Wsm3 is presently being transferred to adapted hard red winter wheat cultivars and can be used directly in wheat improvement.

  3. [Treatment of choroidal noevascularization secondary to angioid streaks with bevacizumab and response: Experience of the ophthalmology department of Hassan II university hospital].

    Science.gov (United States)

    El Bahloul, M; Chraïbi, F; Aounzou, S; Salam Diarra, A; Abdellaoui, M; Benatiya, I; Tahri, H

    2017-11-01

    To evaluate the efficacy of intravitreal bevacizumab in the treatment of choroidal neovascularization (CNV) secondary to angioid streaks. We conducted a prospective study in the ophthalmology department of Hassan II university hospital in Fez, including 12 eyes of 7 patients with CNV associated with angioid streaks. We injected 8 eyes with bevacizumab 1.25mg; best corrected visual acuity (BCVA), fundus examination, fluorescein angiography and optical coherence tomography were performed and analyzed for all patients before and after treatment. The goal of the study was to determine the percentage of patients with stabilization or improvement in BCVA and decreased central macular thickness. Visual acuity on admission was <1/10 in 75% of patients. We injected 8 eyes with anti-VEGF, whereas abstention was appropriate for 4 eyes with disciform scarring. The average number of bevacizumab injections was 4.3±1.3 over a mean follow-up of 14.57 months±5.3. After treatment, BCVA was <1/10 in 12.5% of cases, between 1/10 and 5/10 in 50% of cases, and in 37.5% of patients, it was ≥5/10. Mean central macular thickness decreased from 424.25±137.03μm on admission to 255.75 microns±50.14 post-treatment (P=0.005). Intravitreal bevacizumab is a promising and effective treatment option for the management of CNV associated with angioid streaks, with the requirement however of early treatment and extended follow-up. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. Quality control of gamma camera systems

    Energy Technology Data Exchange (ETDEWEB)

    Bolster, Alison (ed.)

    2003-07-01

    This report has been prepared by the Radionuclide Special Interest Group of the Institute of Physics and Engineering in Medicine. It replaces the Institute of Physical Sciences in Medicine Report 66. Since the publication of that report, there have been important advances, particularly with regard to wholebody imaging, single photon emission computed tomography, gamma camera positron emission tomography and gamma camera computer/software development. To reflect this, Chapters 1, 2 and 3 remain relatively unchanged from the previous version, while Chapters 4, 5, 6 and 7 have been added to cover the four topics mentioned above. These chapters include detailed quality control test procedures for each type of imaging. Recommendations on the frequency at which various performance parameters should be assessed are summarised in Chapter 8, and Chapter 9 deals briefly with the subject of specifying equipment. Requirement for Quality Control. There is often some confusion about the distinction between the terms 'quality assurance' and 'quality control'. Quality assurance (QA) is usually taken to refer to all aspects of a procedure which contribute to the quality of the results obtained. In nuclear medicine, this would include staff training, testing of radiopharmaceuticals, assessment of equipment performance and reporting of clinical studies. Quality control (QC) refers to the specification, assessment, optimisation and maintenance of a particular aspect, such as the performance of the imaging equipment. The specification of equipment for tendering purposes may include aspects of performance which are difficult for the purchaser to confirm. Acceptance testing may require access to specialised equipment and may be performed by the supplier's engineers. It is essential that the purchaser, or an appropriately experienced person acting on behalf of the purchaser, should be closely involved in the acceptance testing. However, for routine QC, it is

  5. Far-infrared cameras for automotive safety

    Science.gov (United States)

    Lonnoy, Jacques; Le Guilloux, Yann; Moreira, Raphael

    2005-02-01

    Far Infrared cameras used initially for the driving of military vehicles are slowly coming into the area of commercial (luxury) cars while providing with the FIR imagery a useful assistance for driving at night or in adverse conditions (fog, smoke, ...). However this imagery needs a minimum driver effort as the image understanding is not so natural as the visible or near IR one. A developing field of FIR cameras is ADAS (Advanced Driver Assistance Systems) where FIR processed imagery fused with other sensors data (radar, ...) is providing a driver warning when dangerous situations are occurring. The communication will concentrate on FIR processed imagery for object or obstacles detection on the road or near the road. FIR imagery highlighting hot spots is a powerful detection tool as it provides a good contrast on some of the most common elements of the road scenery (engines, wheels, gas exhaust pipes, pedestrians, 2 wheelers, animals,...). Moreover FIR algorithms are much more robust than visible ones as there is less variability in image contrast with time (day/night, shadows, ...). We based our detection algorithm on one side on the peculiar aspect of vehicles, pedestrians in FIR images and on the other side on the analysis of motion along time, that allows anticipation of future motion. We will show results obtained with FIR processed imagery within the PAROTO project, supported by the French Ministry of Research, that ended in spring 04.

  6. The design of aerial camera focusing mechanism

    Science.gov (United States)

    Hu, Changchang; Yang, Hongtao; Niu, Haijun

    2015-10-01

    In order to ensure the imaging resolution of aerial camera and compensating defocusing caused by the changing of atmospheric temperature, pressure, oblique photographing distance and other environmental factor [1,2], and to meeting the overall design requirements of the camera for the lower mass and smaller size , the linear focusing mechanism is designed. Through the target surface support, the target surface component is connected with focusing driving mechanism. Make use of precision ball screws, focusing mechanism transforms the input rotary motion of motor into linear motion of the focal plane assembly. Then combined with the form of linear guide restraint movement, the magnetic encoder is adopted to detect the response of displacement. And the closed loop control is adopted to realize accurate focusing. This paper illustrated the design scheme for a focusing mechanism and analyzed its error sources. It has the advantages of light friction and simple transmission chain and reducing the transmission error effectively. And this paper also analyses the target surface by finite element analysis and lightweight design. Proving that the precision of focusing mechanism can achieve higher than 3um, and the focusing range is +/-2mm.

  7. Oil spill detection using hyperspectral infrared camera

    Science.gov (United States)

    Yu, Hui; Wang, Qun; Zhang, Zhen; Zhang, Zhi-jie; Tang, Wei; Tang, Xin; Yue, Song; Wang, Chen-sheng

    2016-11-01

    Oil spill pollution is a severe environmental problem that persists in the marine environment and in inland water systems around the world. Remote sensing is an important part of oil spill response. The hyperspectral images can not only provide the space information but also the spectral information. Pixels of interests generally incorporate information from disparate component that requires quantitative decomposition of these pixels to extract desired information. Oil spill detection can be implemented by applying hyperspectral camera which can collect the hyperspectral data of the oil. By extracting desired spectral signature from hundreds of band information, one can detect and identify oil spill area in vast geographical regions. There are now numerous hyperspectral image processing algorithms developed for target detection. In this paper, we investigate several most widely used target detection algorithm for the identification of surface oil spills in ocean environment. In the experiments, we applied a hyperspectral camera to collect the real life oil spill. The experimental results shows the feasibility of oil spill detection using hyperspectral imaging and the performance of hyperspectral image processing algorithms were also validated.

  8. Mars Cameras Make Panoramic Photography a Snap

    Science.gov (United States)

    2008-01-01

    If you wish to explore a Martian landscape without leaving your armchair, a few simple clicks around the NASA Web site will lead you to panoramic photographs taken from the Mars Exploration Rovers, Spirit and Opportunity. Many of the technologies that enable this spectacular Mars photography have also inspired advancements in photography here on Earth, including the panoramic camera (Pancam) and its housing assembly, designed by the Jet Propulsion Laboratory and Cornell University for the Mars missions. Mounted atop each rover, the Pancam mast assembly (PMA) can tilt a full 180 degrees and swivel 360 degrees, allowing for a complete, highly detailed view of the Martian landscape. The rover Pancams take small, 1 megapixel (1 million pixel) digital photographs, which are stitched together into large panoramas that sometimes measure 4 by 24 megapixels. The Pancam software performs some image correction and stitching after the photographs are transmitted back to Earth. Different lens filters and a spectrometer also assist scientists in their analyses of infrared radiation from the objects in the photographs. These photographs from Mars spurred developers to begin thinking in terms of larger and higher quality images: super-sized digital pictures, or gigapixels, which are images composed of 1 billion or more pixels. Gigapixel images are more than 200 times the size captured by today s standard 4 megapixel digital camera. Although originally created for the Mars missions, the detail provided by these large photographs allows for many purposes, not all of which are limited to extraterrestrial photography.

  9. Vertically Integrated Edgeless Photon Imaging Camera

    Energy Technology Data Exchange (ETDEWEB)

    Fahim, Farah [Fermilab; Deptuch, Grzegorz [Fermilab; Shenai, Alpana [Fermilab; Maj, Piotr [AGH-UST, Cracow; Kmon, Piotr [AGH-UST, Cracow; Grybos, Pawel [AGH-UST, Cracow; Szczygiel, Robert [AGH-UST, Cracow; Siddons, D. Peter [Brookhaven; Rumaiz, Abdul [Brookhaven; Kuczewski, Anthony [Brookhaven; Mead, Joseph [Brookhaven; Bradford, Rebecca [Argonne; Weizeorick, John [Argonne

    2017-01-01

    The Vertically Integrated Photon Imaging Chip - Large, (VIPIC-L), is a large area, small pixel (65μm), 3D integrated, photon counting ASIC with zero-suppressed or full frame dead-time-less data readout. It features data throughput of 14.4 Gbps per chip with a full frame readout speed of 56kframes/s in the imaging mode. VIPIC-L contain 192 x 192 pixel array and the total size of the chip is 1.248cm x 1.248cm with only a 5μm periphery. It contains about 120M transistors. A 1.3M pixel camera module will be developed by arranging a 6 x 6 array of 3D VIPIC-L’s bonded to a large area silicon sensor on the analog side and to a readout board on the digital side. The readout board hosts a bank of FPGA’s, one per VIPIC-L to allow processing of up to 0.7 Tbps of raw data produced by the camera.

  10. Infrared Camera Analysis of Laser Hardening

    Directory of Open Access Journals (Sweden)

    J. Tesar

    2012-01-01

    Full Text Available The improvement of surface properties such as laser hardening becomes very important in present manufacturing. Resulting laser hardening depth and surface hardness can be affected by changes in optical properties of material surface, that is, by absorptivity that gives the ratio between absorbed energy and incident laser energy. The surface changes on tested sample of steel block were made by engraving laser with different scanning velocity and repetition frequency. During the laser hardening the process was observed by infrared (IR camera system that measures infrared radiation from the heated sample and depicts it in a form of temperature field. The images from the IR camera of the sample are shown, and maximal temperatures of all engraved areas are evaluated and compared. The surface hardness was measured, and the hardening depth was estimated from the measured hardness profile in the sample cross-section. The correlation between reached temperature, surface hardness, and hardening depth is shown. The highest and the lowest temperatures correspond to the lowest/highest hardness and the highest/lowest hardening depth.

  11. Foreground extraction for moving RGBD cameras

    Science.gov (United States)

    Junejo, Imran N.; Ahmed, Naveed

    2017-02-01

    In this paper, we propose a simple method to perform foreground extraction for a moving RGBD camera. These cameras have now been available for quite some time. Their popularity is primarily due to their low cost and ease of availability. Although the field of foreground extraction or background subtraction has been explored by the computer vision researchers since a long time, the depth-based subtraction is relatively new and has not been extensively addressed as of yet. Most of the current methods make heavy use of geometric reconstruction, making the solutions quite restrictive. In this paper, we make a novel use RGB and RGBD data: from the RGB frame, we extract corner features (FAST) and then represent these features with the histogram of oriented gradients (HoG) descriptor. We train a non-linear SVM on these descriptors. During the test phase, we make used of the fact that the foreground object has distinct depth ordering with respect to the rest of the scene. That is, we use the positively classified FAST features on the test frame to initiate a region growing to obtain the accurate segmentation of the foreground object from just the RGBD data. We demonstrate the proposed method of a synthetic datasets, and demonstrate encouraging quantitative and qualitative results.

  12. Women's Creation of Camera Phone Culture

    Directory of Open Access Journals (Sweden)

    Dong-Hoo Lee

    2005-01-01

    Full Text Available A major aspect of the relationship between women and the media is the extent to which the new media environment is shaping how women live and perceive the world. It is necessary to understand, in a concrete way, how the new media environment is articulated to our gendered culture, how the symbolic or physical forms of the new media condition women’s experiences, and the degree to which a ‘post-gendered re-codification’ can be realized within a new media environment. This paper intends to provide an ethnographic case study of women’s experiences with camera phones, examining the extent to which these experiences recreate or reconstruct women’s subjectivity or identity. By taking a close look at the ways in which women utilize and appropriate the camera phone in their daily lives, it focuses not only on women’s cultural practices in making meanings but also on their possible effect in the deconstruction of gendered techno-culture.

  13. Electronic Still Camera Project on STS-48

    Science.gov (United States)

    1991-01-01

    On behalf of NASA, the Office of Commercial Programs (OCP) has signed a Technical Exchange Agreement (TEA) with Autometric, Inc. (Autometric) of Alexandria, Virginia. The purpose of this agreement is to evaluate and analyze a high-resolution Electronic Still Camera (ESC) for potential commercial applications. During the mission, Autometric will provide unique photo analysis and hard-copy production. Once the mission is complete, Autometric will furnish NASA with an analysis of the ESC s capabilities. Electronic still photography is a developing technology providing the means by which a hand held camera electronically captures and produces a digital image with resolution approaching film quality. The digital image, stored on removable hard disks or small optical disks, can be converted to a format suitable for downlink transmission, or it can be enhanced using image processing software. The on-orbit ability to enhance or annotate high-resolution images and then downlink these images in real-time will greatly improve Space Shuttle and Space Station capabilities in Earth observations and on-board photo documentation.

  14. Deconvolution of Camera Instrument Response Functions.

    Science.gov (United States)

    Lewis, John H; Jamiolkowski, Ryan M; Woody, Michael S; Ostap, E Michael; Goldman, Yale E

    2017-03-28

    Temporal sequences of fluorescence intensities in single-molecule experiments are often obtained from stacks of camera images. The dwell times of different macromolecular structural or functional states, correlated with characteristic fluorescence intensities, are extracted from the images and combined into dwell time distributions that are fitted by kinetic functions to extract corresponding rate constants. The frame rate of the camera limits the time resolution of the experiment and thus the fastest rate processes that can be reliably detected and quantified. However, including the influence of discrete sampling (framing) on the detected time series in the fitted model enables rate processes near to the frame rate to be reliably estimated. This influence, similar to the instrument response function in other types of instruments, such as pulsed emission decay fluorometers, is easily incorporated into the fitted model. The same concept applies to any temporal data that is low-pass filtered or decimated to improve signal to noise ratio. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  15. CCD Camera Detection of HIV Infection.

    Science.gov (United States)

    Day, John R

    2017-01-01

    Rapid and precise quantification of the infectivity of HIV is important for molecular virologic studies, as well as for measuring the activities of antiviral drugs and neutralizing antibodies. An indicator cell line, a CCD camera, and image-analysis software are used to quantify HIV infectivity. The cells of the P4R5 line, which express the receptors for HIV infection as well as β-galactosidase under the control of the HIV-1 long terminal repeat, are infected with HIV and then incubated 2 days later with X-gal to stain the infected cells blue. Digital images of monolayers of the infected cells are captured using a high resolution CCD video camera and a macro video zoom lens. A software program is developed to process the images and to count the blue-stained foci of infection. The described method allows for the rapid quantification of the infected cells over a wide range of viral inocula with reproducibility, accuracy and at relatively low cost.

  16. Scalable IC Platform for Smart Cameras

    Directory of Open Access Journals (Sweden)

    Harry Broers

    2005-08-01

    Full Text Available Smart cameras are among the emerging new fields of electronics. The points of interest are in the application areas, software and IC development. In order to reduce cost, it is worthwhile to invest in a single architecture that can be scaled for the various application areas in performance (and resulting power consumption. In this paper, we show that the combination of an SIMD (single-instruction multiple-data processor and a general-purpose DSP is very advantageous for the image processing tasks encountered in smart cameras. While the SIMD processor gives the very high performance necessary by exploiting the inherent data parallelism found in the pixel crunching part of the algorithms, the DSP offers a friendly approach to the more complex tasks. The paper continues to motivate that SIMD processors have very convenient scaling properties in silicon, making the complete, SIMD-DSP architecture suitable for different application areas without changing the software suite. Analysis of the changes in power consumption due to scaling shows that for typical image processing tasks, it is beneficial to scale the SIMD processor to use the maximum level of parallelism available in the algorithm if the IC supply voltage can be lowered. If silicon cost is of importance, the parallelism of the processor should be scaled to just reach the desired performance given the speed of the silicon.

  17. Online camera-gyroscope autocalibration for cell phones.

    Science.gov (United States)

    Jia, Chao; Evans, Brian L

    2014-12-01

    The gyroscope is playing a key role in helping estimate 3D camera rotation for various vision applications on cell phones, including video stabilization and feature tracking. Successful fusion of gyroscope and camera data requires that the camera, gyroscope, and their relative pose to be calibrated. In addition, the timestamps of gyroscope readings and video frames are usually not well synchronized. Previous paper performed camera-gyroscope calibration and synchronization offline after the entire video sequence has been captured with restrictions on the camera motion, which is unnecessarily restrictive for everyday users to run apps that directly use the gyroscope. In this paper, we propose an online method that estimates all the necessary parameters, whereas a user is capturing video. Our contributions are: 1) simultaneous online camera self-calibration and camera-gyroscope calibration based on an implicit extended Kalman filter and 2) generalization of the multiple-view coplanarity constraint on camera rotation in a rolling shutter camera model for cell phones. The proposed method is able to estimate the needed calibration and synchronization parameters online with all kinds of camera motion and can be embedded in gyro-aided applications, such as video stabilization and feature tracking. Both Monte Carlo simulation and cell phone experiments show that the proposed online calibration and synchronization method converge fast to the ground truth values.

  18. Kimchi attenuates fatty streak formation in the aorta of low-density lipoprotein receptor knockout mice via inhibition of endoplasmic reticulum stress and apoptosis.

    Science.gov (United States)

    Woo, Minji; Kim, Mijeong; Noh, Jeong Sook; Park, Chan Hum; Song, Yeong Ok

    2017-12-01

    Endoplasmic reticulum (ER) stress is positively associated with atherosclerosis via elevating macrophage cell death and plaque formation, in which oxidative stress plays a pivotal role. Antioxidative, lipid-lowering, and anti-atherogenic effects of kimchi, a Korean fermented vegetable, have been established, wherein capsaicin, ascorbic acid, quercetin, 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid, and lactic acids were identified. In this study, mechanisms of action of kimchi methanol extracts (KME) on fatty streak formation via suppression of ER stress and apoptosis in aorta were examined in low-density lipoprotein receptor knockout mice. Mice fed a high cholesterol diet with an oral administration of KME (KME group, 200 mg·kg-bw -1 ·day -1 ) or distilled water (control group) for 8 weeks (n = 20 for group). Plasma lipid and oxidative stress levels were evaluated. Protein expression was measured by western blot assay. Fatty streak lesion size and the degree of apoptosis were examined in the aorta. Compared to the control group, in the KME group, plasma lipids levels were decreased and oxidative stress was alleviated ( P < 0.05). Protein expression levels of nuclear factor (erythroid-derived 2)-like 2-mediated antioxidants in aorta were increased whereas those for ER stress markers, glucose regulated protein 78, phospho-protein kinase RNA-like ER kinase, phospho-eukaryotic initiation factor 2 subunit α, X-box binding protein 1, and C/EBP homologous protein were decreased in the KME group ( P < 0.05). Moreover, apoptosis was suppressed via downregulation of phospho-c-Jun N-terminal kinase, bcl-2-associated X protein, caspases-9, and -3 with a concomitant upregulation of anti-apoptotic protein, B-cell lymphoma 2 ( P < 0.05). Fatty streak lesion size was reduced and the degree of apoptosis was less severe in the KME group ( P < 0.05). In conclusion, antioxidant activity of KME might prevent fatty streak formation through, in part, inhibition of ER stress and

  19. Replication and encapsidation of the viroid-like satellite RNA of lucerne transient streak virus are supported in divergent hosts by cocksfoot mottle virus and turnip rosette virus.

    Science.gov (United States)

    Sehgal, O P; Sinha, R C; Gellatly, D L; Ivanov, I; AbouHaidar, M G

    1993-04-01

    Cocksfoot mottle sobemovirus supports replication and encapsidation of the viroid-like satellite RNA (sat-RNA) of lucerne transient streak virus (LTSV) in two monocotyledonous species, Triticum aestivum and Dactylis glomerata. Additionally, LTSV sat-RNA replicates effectively in the presence of turnip rosette sobemovirus in Brassica rapa, Raphanus raphanistrum and Sinapsis arvensis, but not in Thlaspi arvense or Nicotiana bigelovii, indicating that host species markedly influence this interaction. Previous reports of the association between LTSV sat-RNA and helper sobemoviruses were limited to dicotyledonous hosts. Our results demonstrate that the biological interaction between these two entities spans divergent dicotyledonous and monocotyledonous species.

  20. Mycosphaerella fijiensis, the black leaf streak pathogen of banana: progress towards understanding pathogen biology and detection, disease development, and the challenges of control.

    Science.gov (United States)

    Churchill, Alice C L

    2011-05-01

    Banana (Musa spp.) is grown throughout the tropical and subtropical regions of the world. The fruits are a key staple food in many developing countries and a source of income for subsistence farmers. Bananas are also a major, multibillion-dollar export commodity for consumption primarily in developed countries, where few banana cultivars are grown. The fungal pathogen Mycosphaerella fijiensis causes black leaf streak disease (BLSD; aka black Sigatoka leaf spot) on the majority of edible banana cultivars grown worldwide. The fact that most of these cultivars are sterile and unsuitable for the breeding of resistant lines necessitates the extensive use of fungicides as the primary means of disease control. BLSD is a significant threat to the food security of resource-poor populations who cannot afford fungicides, and increases the environmental and health hazards where large-acreage monocultures of banana (Cavendish subgroup, AAA genome) are grown for export. Mycosphaerella fijiensis M. Morelet is a sexual, heterothallic fungus having Pseudocercospora fijiensis (M. Morelet) Deighton as the anamorph stage. It is a haploid, hemibiotrophic ascomycete within the class Dothideomycetes, order Capnodiales and family Mycosphaerellaceae. Its taxonomic placement is based on DNA phylogeny, morphological analyses and cultural characteristics. Mycosphaerella fijiensis is a leaf pathogen that causes reddish-brown streaks running parallel to the leaf veins, which aggregate to form larger, dark-brown to black compound streaks. These streaks eventually form fusiform or elliptical lesions that coalesce, form a water-soaked border with a yellow halo and, eventually, merge to cause extensive leaf necrosis. The disease does not kill the plants immediately, but weakens them by decreasing the photosynthetic capacity of leaves, causing a reduction in the quantity and quality of fruit, and inducing the premature ripening of fruit harvested from infected plants. Although Musa spp. are the

  1. Motorcycle detection and counting using stereo camera, IR camera, and microphone array

    Science.gov (United States)

    Ling, Bo; Gibson, David R. P.; Middleton, Dan

    2013-03-01

    Detection, classification, and characterization are the key to enhancing motorcycle safety, motorcycle operations and motorcycle travel estimation. Average motorcycle fatalities per Vehicle Mile Traveled (VMT) are currently estimated at 30 times those of auto fatalities. Although it has been an active research area for many years, motorcycle detection still remains a challenging task. Working with FHWA, we have developed a hybrid motorcycle detection and counting system using a suite of sensors including stereo camera, thermal IR camera and unidirectional microphone array. The IR thermal camera can capture the unique thermal signatures associated with the motorcycle's exhaust pipes that often show bright elongated blobs in IR images. The stereo camera in the system is used to detect the motorcyclist who can be easily windowed out in the stereo disparity map. If the motorcyclist is detected through his or her 3D body recognition, motorcycle is detected. Microphones are used to detect motorcycles that often produce low frequency acoustic signals. All three microphones in the microphone array are placed in strategic locations on the sensor platform to minimize the interferences of background noises from sources such as rain and wind. Field test results show that this hybrid motorcycle detection and counting system has an excellent performance.

  2. From the Pinhole Camera to the Shape of a Lens: The Camera-Obscura Reloaded

    Science.gov (United States)

    Ziegler, Max; Priemer, Burkhard

    2015-01-01

    We demonstrate how the form of a plano-convex lens and a derivation of the thin lens equation can be understood through simple physical considerations. The basic principle is the extension of the pinhole camera using additional holes. The resulting images are brought into coincidence through the deflection of light with an arrangement of prisms.…

  3. Lights, Camera, AG-Tion: Promoting Agricultural and Environmental Education on Camera

    Science.gov (United States)

    Fuhrman, Nicholas E.

    2016-01-01

    Viewing of online videos and television segments has become a popular and efficient way for Extension audiences to acquire information. This article describes a unique approach to teaching on camera that may help Extension educators communicate their messages with comfort and personality. The S.A.L.A.D. approach emphasizes using relevant teaching…

  4. Vascular Streak Dieback of cacao in Southeast Asia and Melanesia: in planta detection of the pathogen and a new taxonomy.

    Science.gov (United States)

    Samuels, Gary J; Ismaiel, Adnan; Rosmana, Ade; Junaid, Muhammad; Guest, David; McMahon, Peter; Keane, Philip; Purwantara, Agus; Lambert, Smilja; Rodriguez-Carres, Marianela; Cubeta, Marc A

    2012-01-01

    Vascular Streak Dieback (VSD) disease of cacao (Theobroma cacao) in Southeast Asia and Melanesia is caused by a basidiomycete (Ceratobasidiales) fungus Oncobasidium theobromae (syn. =Thanatephorus theobromae). The most characteristic symptoms of the disease are green-spotted leaf chlorosis or, commonly since about 2004, necrotic blotches, followed by senescence of leaves beginning on the second or third flush behind the shoot apex, and blackening of infected xylem in the vascular traces at the leaf scars resulting from the abscission of infected leaves. Eventually the shoot apex is killed and infected branches die. In susceptible cacao the fungus may grow through the xylem down into the main stem and kill a mature cacao tree. Infections in the stem of young plants prior to the formation of the first 3-4 lateral branches usually kill the plant. Basidiospores released from corticioid basidiomata developed on leaf scars or along cracks in the main vein of infected leaves infect young leaves. The pathogen commonly infects cacao but there are rare reports from avocado. As both crops are introduced to the region, the pathogen is suspected to occur asymptomatically in native vegetation. The pathogen is readily isolated but cultures cannot be maintained. In this study, DNA was extracted from pure cultures of O. theobromae obtained from infected cacao plants sampled from Indonesia. The internal transcribed spacer region (ITS), consisting of ITS1, 5.8S ribosomal RNA and ITS2, and a portion of nuclear large subunit (LSU) were sequenced. Phylogenetic analysis of ITS sequences placed O. theobromae sister to Ceratobasidium anastomosis groups AG-A, AG-Bo, and AG-K with high posterior probability. Therefore the new combination Ceratobasidium theobromae is proposed. A PCR-based protocol was developed to detect and identify C. theobromae in plant tissue of cacao enabling early detection of the pathogen in plants. A second species of Ceratobasidium, Ceratobasidium ramicola

  5. A wide-angle camera module for disposable endoscopy

    Science.gov (United States)

    Shim, Dongha; Yeon, Jesun; Yi, Jason; Park, Jongwon; Park, Soo Nam; Lee, Nanhee

    2016-08-01

    A wide-angle miniaturized camera module for disposable endoscope is demonstrated in this paper. A lens module with 150° angle of view (AOV) is designed and manufactured. All plastic injection-molded lenses and a commercial CMOS image sensor are employed to reduce the manufacturing cost. The image sensor and LED illumination unit are assembled with a lens module. The camera module does not include a camera processor to further reduce its size and cost. The size of the camera module is 5.5 × 5.5 × 22.3 mm3. The diagonal field of view (FOV) of the camera module is measured to be 110°. A prototype of a disposable endoscope is implemented to perform a pre-clinical animal testing. The esophagus of an adult beagle dog is observed. These results demonstrate the feasibility of a cost-effective and high-performance camera module for disposable endoscopy.

  6. Performance evaluation and clinical applications of 3D plenoptic cameras

    Science.gov (United States)

    Decker, Ryan; Shademan, Azad; Opfermann, Justin; Leonard, Simon; Kim, Peter C. W.; Krieger, Axel

    2015-06-01

    The observation and 3D quantification of arbitrary scenes using optical imaging systems is challenging, but increasingly necessary in many fields. This paper provides a technical basis for the application of plenoptic cameras in medical and medical robotics applications, and rigorously evaluates camera integration and performance in the clinical setting. It discusses plenoptic camera calibration and setup, assesses plenoptic imaging in a clinically relevant context, and in the context of other quantitative imaging technologies. We report the methods used for camera calibration, precision and accuracy results in an ideal and simulated surgical setting. Afterwards, we report performance during a surgical task. Test results showed the average precision of the plenoptic camera to be 0.90mm, increasing to 1.37mm for tissue across the calibrated FOV. The ideal accuracy was 1.14mm. The camera showed submillimeter error during a simulated surgical task.

  7. Camera systems in human motion analysis for biomedical applications

    Science.gov (United States)

    Chin, Lim Chee; Basah, Shafriza Nisha; Yaacob, Sazali; Juan, Yeap Ewe; Kadir, Aida Khairunnisaa Ab.

    2015-05-01

    Human Motion Analysis (HMA) system has been one of the major interests among researchers in the field of computer vision, artificial intelligence and biomedical engineering and sciences. This is due to its wide and promising biomedical applications, namely, bio-instrumentation for human computer interfacing and surveillance system for monitoring human behaviour as well as analysis of biomedical signal and image processing for diagnosis and rehabilitation applications. This paper provides an extensive review of the camera system of HMA, its taxonomy, including camera types, camera calibration and camera configuration. The review focused on evaluating the camera system consideration of the HMA system specifically for biomedical applications. This review is important as it provides guidelines and recommendation for researchers and practitioners in selecting a camera system of the HMA system for biomedical applications.

  8. Development of SED Camera for Quasars in Early Universe (SQUEAN)

    OpenAIRE

    Kim, Sanghyuk; Jeon, Yiseul; Lee, Hye-In; Park, Woojin; Ji, Tae-Geun; Hyun, Minhee; Choi, Changsu; Im, Myungshin; Pak, Soojong

    2016-01-01

    We describe the characteristics and performance of a camera system, Spectral energy distribution Camera for Quasars in Early Universe (SQUEAN). It was developed to measure SEDs of high redshift quasar candidates (z $\\gtrsim$ 5) and other targets, e.g., young stellar objects, supernovae, and gamma-ray bursts, and to trace the time variability of SEDs of objects such as active galactic nuclei (AGNs). SQUEAN consists of an on-axis focal plane camera module, an auto-guiding system, and mechanical...

  9. The Policy of Enforcement: Red Light Cameras and Racial Profiling

    OpenAIRE

    Eger, Robert J.; Fortner, C. Kevin; Slade, Catherine P.

    2015-01-01

    The article of record as published may be located at http://dx.doi.org/10.1177/1098611115586174 We explore the question of whether some of the often conflicting evidence of racial profiling can be cleared up using red light camera observations to measure racial disparities in traffic violations. Using data from cameras at intersections matched to census data, we find that although citations from the red light cameras are issued to a disproportionate number of minorities based o...

  10. Exploring Computation-Communication Tradeoffs in Camera Systems

    OpenAIRE

    Mazumdar, Amrita; Moreau, Thierry; Kim, Sung; Cowan, Meghan; Alaghi, Armin; Ceze, Luis; Oskin, Mark; Sathe, Visvesh

    2017-01-01

    Cameras are the defacto sensor. The growing demand for real-time and low-power computer vision, coupled with trends towards high-efficiency heterogeneous systems, has given rise to a wide range of image processing acceleration techniques at the camera node and in the cloud. In this paper, we characterize two novel camera systems that use acceleration techniques to push the extremes of energy and performance scaling, and explore the computation-communication tradeoffs in their design. The firs...

  11. Resolution of slit-lamp microscopy photography using various cameras.

    Science.gov (United States)

    Ye, Yufeng; Jiang, Hong; Zhang, Huicheng; Karp, Carol L; Zhong, Jianguang; Tao, Aizhu; Shao, Yilei; Wang, Jianhua

    2013-05-01

    To evaluate the resolutions of slit-lamp microscopy photography using various cameras. Evaluation of diagnostic test or technology. Healthy subjects were imaged with these adapted cameras through slit-lamp microscopy. A total of 8 cameras, including 6 custom-mounted slit-lamp cameras and 2 commercial slit-lamp cameras, were tested with standard slit-lamp microscopy devices for imaging of the eye. Various magnifications were used during imaging. A standard resolution test plate was used to test the resolutions at different magnifications. These outcomes were compared with commercial slit-lamp cameras. The main measurements included the display spatial resolutions, image spatial resolutions, and ocular resolutions. The outcome also includes the relationships between resolution and the pixel density of the displays and images. All cameras were successfully adapted to the slit-lamp microscopy, and high-quality ocular images were obtained. Differences in the display spatial resolutions were found among cameras [analysis of variance (ANOVA), Pcameras using the high-definition multimedia interface (HDMI) compared with others, including cameras in smart phones. The display resolutions of smart phone displays were greater than cameras with video graphics array displays. The display spatial resolutions were found as a function of display pixel density (r>0.95, P0.85, Pcameras (ANOVA, P0.98, P0.85, Pcamera yielded the highest image spatial resolution. However, the ocular resolution through binocular viewing of the slit-lamp microscopy was found to have the highest resolution compared with the display and image spatial resolutions of all of the cameras. Several cameras can be adapted with slit-lamp microscopy for ophthalmic imaging, yielding various display and image spatial resolutions. However, the resolution seemed to not be as good as ocular viewing through the slit-lamp biomicroscope.

  12. Smart Cameras for Remote Science Survey

    Science.gov (United States)

    Thompson, David R.; Abbey, William; Allwood, Abigail; Bekker, Dmitriy; Bornstein, Benjamin; Cabrol, Nathalie A.; Castano, Rebecca; Estlin, Tara; Fuchs, Thomas; Wagstaff, Kiri L.

    2012-01-01

    Communication with remote exploration spacecraft is often intermittent and bandwidth is highly constrained. Future missions could use onboard science data understanding to prioritize downlink of critical features [1], draft summary maps of visited terrain [2], or identify targets of opportunity for followup measurements [3]. We describe a generic approach to classify geologic surfaces for autonomous science operations, suitable for parallelized implementations in FPGA hardware. We map these surfaces with texture channels - distinctive numerical signatures that differentiate properties such as roughness, pavement coatings, regolith characteristics, sedimentary fabrics and differential outcrop weathering. This work describes our basic image analysis approach and reports an initial performance evaluation using surface images from the Mars Exploration Rovers. Future work will incorporate these methods into camera hardware for real-time processing.

  13. CHAMP (Camera, Handlens, and Microscope Probe)

    Science.gov (United States)

    Mungas, Greg S.; Boynton, John E.; Balzer, Mark A.; Beegle, Luther; Sobel, Harold R.; Fisher, Ted; Klein, Dan; Deans, Matthew; Lee, Pascal; Sepulveda, Cesar A.

    2005-01-01

    CHAMP (Camera, Handlens And Microscope Probe)is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As a robotic arm-mounted imager, CHAMP supports stereo imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision rangefinding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. CHAMP was originally developed through the Mars Instrument Development Program (MIDP) in support of robotic field investigations, but may also find application in new areas such as robotic in-orbit servicing and maintenance operations associated with spacecraft and human operations. We overview CHAMP'S instrument performance and basic design considerations below.

  14. CHAMP - Camera, Handlens, and Microscope Probe

    Science.gov (United States)

    Mungas, G. S.; Beegle, L. W.; Boynton, J.; Sepulveda, C. A.; Balzer, M. A.; Sobel, H. R.; Fisher, T. A.; Deans, M.; Lee, P.

    2005-01-01

    CHAMP (Camera, Handlens And Microscope Probe) is a novel field microscope capable of color imaging with continuously variable spatial resolution from infinity imaging down to diffraction-limited microscopy (3 micron/pixel). As an arm-mounted imager, CHAMP supports stereo-imaging with variable baselines, can continuously image targets at an increasing magnification during an arm approach, can provide precision range-finding estimates to targets, and can accommodate microscopic imaging of rough surfaces through a image filtering process called z-stacking. Currently designed with a filter wheel with 4 different filters, so that color and black and white images can be obtained over the entire Field-of-View, future designs will increase the number of filter positions to include 8 different filters. Finally, CHAMP incorporates controlled white and UV illumination so that images can be obtained regardless of sun position, and any potential fluorescent species can be identified so the most astrobiologically interesting samples can be identified.

  15. Operational experience with a CID camera system

    CERN Document Server

    Welsch, Carsten P; Burel, Bruno; Lefèvre, Thibaut

    2006-01-01

    In future high intensity, high energy accelerators particle losses must be minimized as activation of the vacuum chambers or other components makes maintenance and upgrade work time consuming and costly. It is imperative to have a clear understanding of the mechanisms that can lead to halo formation, and to have the possibility to test available theoretical models with an adequate experimental setup. Measurements based on optical transition radiation (OTR) provide an interesting opportunity for analyzing the transverse beam profile due to the fast time response and very good linearity of the signal with respect to the beam intensity. On the other hand, the dynamic range of typical acquisition systems as they are used in the CLIC test facility (CTF3) is typically limited and must be improved before these systems can be applied to halo measurements. One possibility for high dynamic range measurements is an innovative camera system based on charge injection device (CID) technology. With possible future measureme...

  16. Relevance of ellipse eccentricity for camera calibration

    Science.gov (United States)

    Mordwinzew, W.; Tietz, B.; Boochs, F.; Paulus, D.

    2015-05-01

    Plane circular targets are widely used within calibrations of optical sensors through photogrammetric set-ups. Due to this popularity, their advantages and disadvantages are also well studied in the scientific community. One main disadvantage occurs when the projected target is not parallel to the image plane. In this geometric constellation, the target has an elliptic geometry with an offset between its geometric and its projected center. This difference is referred to as ellipse eccentricity and is a systematic error which, if not treated accordingly, has a negative impact on the overall achievable accuracy. The magnitude and direction of eccentricity errors are dependent on various factors. The most important one is the target size. The bigger an ellipse in the image is, the bigger the error will be. Although correction models dealing with eccentricity have been available for decades, it is mostly seen as a planning task in which the aim is to choose the target size small enough so that the resulting eccentricity error remains negligible. Besides the fact that advanced mathematical models are available and that the influence of this error on camera calibration results is still not completely investigated, there are various additional reasons why bigger targets can or should not be avoided. One of them is the growing image resolution as a by-product from advancements in the sensor development. Here, smaller pixels have a lower S/N ratio, necessitating more pixels to assure geometric quality. Another scenario might need bigger targets due to larger scale differences whereas distant targets should still contain enough information in the image. In general, bigger ellipses contain more contour pixels and therefore more information. This supports the target-detection algorithms to perform better even at non-optimal conditions such as data from sensors with a high noise level. In contrast to rather simple measuring situations in a stereo or multi-image mode, the impact

  17. Neutron camera employing row and column summations

    Science.gov (United States)

    Clonts, Lloyd G.; Diawara, Yacouba; Donahue, Jr, Cornelius; Montcalm, Christopher A.; Riedel, Richard A.; Visscher, Theodore

    2016-06-14

    For each photomultiplier tube in an Anger camera, an R.times.S array of preamplifiers is provided to detect electrons generated within the photomultiplier tube. The outputs of the preamplifiers are digitized to measure the magnitude of the signals from each preamplifier. For each photomultiplier tube, a corresponding summation circuitry including R row summation circuits and S column summation circuits numerically add the magnitudes of the signals from preamplifiers for each row and for each column to generate histograms. For a P.times.Q array of photomultiplier tubes, P.times.Q summation circuitries generate P.times.Q row histograms including R entries and P.times.Q column histograms including S entries. The total set of histograms include P.times.Q.times.(R+S) entries, which can be analyzed by a position calculation circuit to determine the locations of events (detection of a neutron).

  18. Calibration of a Stereo Radiation Detection Camera Using Planar Homography

    Directory of Open Access Journals (Sweden)

    Seung-Hae Baek

    2016-01-01

    Full Text Available This paper proposes a calibration technique of a stereo gamma detection camera. Calibration of the internal and external parameters of a stereo vision camera is a well-known research problem in the computer vision society. However, few or no stereo calibration has been investigated in the radiation measurement research. Since no visual information can be obtained from a stereo radiation camera, it is impossible to use a general stereo calibration algorithm directly. In this paper, we develop a hybrid-type stereo system which is equipped with both radiation and vision cameras. To calibrate the stereo radiation cameras, stereo images of a calibration pattern captured from the vision cameras are transformed in the view of the radiation cameras. The homography transformation is calibrated based on the geometric relationship between visual and radiation camera coordinates. The accuracy of the stereo parameters of the radiation camera is analyzed by distance measurements to both visual light and gamma sources. The experimental results show that the measurement error is about 3%.

  19. Neutron emissivity profile camera diagnostics considering present and future tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, S. [EURATOM-VR Association, Uppsala (Sweden)

    2001-12-01

    This thesis describes the neutron profile camera situated at JET. The profile camera is one of the most important neutron emission diagnostic devices operating at JET. It gives useful information of the total neutron yield rate but also about the neutron emissivity distribution. Data analysis was performed in order to compare three different calibration methods. The data was collected from the deuterium campaign, C4, in the beginning of 2001. The thesis also includes a section about the implication of a neutron profile camera for ITER, where the issue regarding interface difficulties is in focus. The ITER JCT (Joint Central Team) proposal of a neutron camera for ITER is studied in some detail.

  20. Investigating the Suitability of Mirrorless Cameras in Terrestrial Photogrammetric Applications

    Science.gov (United States)

    Incekara, A. H.; Seker, D. Z.; Delen, A.; Acar, A.

    2017-11-01

    Digital single-lens reflex cameras (DSLR) which are commonly referred as mirrored cameras are preferred for terrestrial photogrammetric applications such as documentation of cultural heritage, archaeological excavations and industrial measurements. Recently, digital cameras which are called as mirrorless systems that can be used with different lens combinations have become available for using similar applications. The main difference between these two camera types is the presence of the mirror mechanism which means that the incoming beam towards the lens is different in the way it reaches the sensor. In this study, two different digital cameras, one with a mirror (Nikon D700) and the other without a mirror (Sony a6000), were used to apply close range photogrammetric application on the rock surface at Istanbul Technical University (ITU) Ayazaga Campus. Accuracy of the 3D models created by means of photographs taken with both cameras were compared with each other using difference values between field and model coordinates which were obtained after the alignment of the photographs. In addition, cross sections were created on the 3D models for both data source and maximum area difference between them is quite small because they are almost overlapping. The mirrored camera has become more consistent in itself with respect to the change of model coordinates for models created with photographs taken at different times, with almost the same ground sample distance. As a result, it has been determined that mirrorless cameras and point cloud produced using photographs obtained from these cameras can be used for terrestrial photogrammetric studies.

  1. A SPATIO-SPECTRAL CAMERA FOR HIGH RESOLUTION HYPERSPECTRAL IMAGING

    Directory of Open Access Journals (Sweden)

    S. Livens

    2017-08-01

    Full Text Available Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600–900 nm in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots, horticulture (crop status monitoring to evaluate irrigation management in strawberry fields and geology (meteorite detection on a grassland field. Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475–925 nm, and we discuss future work.

  2. Camera Traps Can Be Heard and Seen by Animals

    Science.gov (United States)

    Meek, Paul D.; Ballard, Guy-Anthony; Fleming, Peter J. S.; Schaefer, Michael; Williams, Warwick; Falzon, Greg

    2014-01-01

    Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5) and infrared illumination outputs (n = 7) of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21) and assessed the vision ranges (n = 3) of mammals species (where data existed) to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals’ hearing and produce illumination that can be seen by many species. PMID:25354356

  3. Operator-based homogeneous coordinates: application in camera document scanning

    Science.gov (United States)

    Juarez-Salazar, Rigoberto; Diaz-Ramirez, Victor H.

    2017-07-01

    An operator-based approach for the study of homogeneous coordinates and projective geometry is proposed. First, some basic geometrical concepts and properties of the operators are investigated in the one- and two-dimensional cases. Then, the pinhole camera model is derived, and a simple method for homography estimation and camera calibration is explained. The usefulness of the analyzed theoretical framework is exemplified by addressing the perspective correction problem for a camera document scanning application. Several experimental results are provided for illustrative purposes. The proposed approach is expected to provide practical insights for inexperienced students on camera calibration, computer vision, and optical metrology among others.

  4. Improved Tracking of Targets by Cameras on a Mars Rover

    Science.gov (United States)

    Kim, Won; Ansar, Adnan; Steele, Robert

    2007-01-01

    A paper describes a method devised to increase the robustness and accuracy of tracking of targets by means of three stereoscopic pairs of video cameras on a Mars-rover-type exploratory robotic vehicle. Two of the camera pairs are mounted on a mast that can be adjusted in pan and tilt; the third camera pair is mounted on the main vehicle body. Elements of the method include a mast calibration, a camera-pointing algorithm, and a purely geometric technique for handing off tracking between different camera pairs at critical distances as the rover approaches a target of interest. The mast calibration is an extension of camera calibration in which the camera images of calibration targets at known positions are collected at various pan and tilt angles. In the camerapointing algorithm, pan and tilt angles are computed by a closed-form, non-iterative solution of inverse kinematics of the mast combined with mathematical models of the cameras. The purely geometric camera-handoff technique involves the use of stereoscopic views of a target of interest in conjunction with the mast calibration.

  5. Geometric Stability and Lens Decentering in Compact Digital Cameras

    Science.gov (United States)

    Sanz-Ablanedo, Enoc; Rodríguez-Pérez, José Ramón; Armesto, Julia; Taboada, María Flor Álvarez

    2010-01-01

    A study on the geometric stability and decentering present in sensor-lens systems of six identical compact digital cameras has been conducted. With regard to geometrical stability, the variation of internal geometry parameters (principal distance, principal point position and distortion parameters) was considered. With regard to lens decentering, the amount of radial and tangential displacement resulting from decentering distortion was related with the precision of the camera and with the offset of the principal point from the geometric center of the sensor. The study was conducted with data obtained after 372 calibration processes (62 per camera). The tests were performed for each camera in three situations: during continuous use of the cameras, after camera power off/on and after the full extension and retraction of the zoom-lens. Additionally, 360 new calibrations were performed in order to study the variation of the internal geometry when the camera is rotated. The aim of this study was to relate the level of stability and decentering in a camera with the precision and quality that can be obtained. An additional goal was to provide practical recommendations about photogrammetric use of such cameras. PMID:22294886

  6. VIDEO-BASED POINT CLOUD GENERATION USING MULTIPLE ACTION CAMERAS

    Directory of Open Access Journals (Sweden)

    T. Teo

    2015-05-01

    Full Text Available Due to the development of action cameras, the use of video technology for collecting geo-spatial data becomes an important trend. The objective of this study is to compare the image-mode and video-mode of multiple action cameras for 3D point clouds generation. Frame images are acquired from discrete camera stations while videos are taken from continuous trajectories. The proposed method includes five major parts: (1 camera calibration, (2 video conversion and alignment, (3 orientation modelling, (4 dense matching, and (5 evaluation. As the action cameras usually have large FOV in wide viewing mode, camera calibration plays an important role to calibrate the effect of lens distortion before image matching. Once the camera has been calibrated, the author use these action cameras to take video in an indoor environment. The videos are further converted into multiple frame images based on the frame rates. In order to overcome the time synchronous issues in between videos from different viewpoints, an additional timer APP is used to determine the time shift factor between cameras in time alignment. A structure form motion (SfM technique is utilized to obtain the image orientations. Then, semi-global matching (SGM algorithm is adopted to obtain dense 3D point clouds. The preliminary results indicated that the 3D points from 4K video are similar to 12MP images, but the data acquisition performance of 4K video is more efficient than 12MP digital images.

  7. Establishing a common coordinate view in multiple moving aerial cameras

    Science.gov (United States)

    Sheikh, Yaser; Gritai, Alexei; Junejo, Imran; Muise, Robert; Mahalanobis, Abhijit; Shah, Mubarak

    2005-05-01

    A camera mounted on an aerial vehicle provides an excellent means of monitoring large areas of a scene. Utilizing several such cameras on different aerial vehicles allows further flexibility, in terms of increased visual scope and in the pursuit of multiple targets. The underlying concept of such co-operative sensing is to use inter-camera relationships to give global context to 'locally' obtained information at each camera. It is desirable, therefore, that the data collected at each camera and the inter-camera relationship discerned by the system be presented in a coherent visualization. Since the cameras are mounted on UAVs, large swaths of areas may be traversed in a short period of time, coherent visualization is indispensable for applications like surveillance and reconnaissance. While most visualization approaches have hitherto focused on data from a single camera at a time, as a consequence of tracking objects across cameras, we show that widely separated mosaics can be aligned, both in space and color, for concurrent visualization. Results are shown on a number of real sequences, validating our qualitative models.

  8. Calibration Techniques for Accurate Measurements by Underwater Camera Systems

    Science.gov (United States)

    Shortis, Mark

    2015-01-01

    Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems. PMID:26690172

  9. Camera traps can be heard and seen by animals.

    Science.gov (United States)

    Meek, Paul D; Ballard, Guy-Anthony; Fleming, Peter J S; Schaefer, Michael; Williams, Warwick; Falzon, Greg

    2014-01-01

    Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5) and infrared illumination outputs (n = 7) of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21) and assessed the vision ranges (n = 3) of mammals species (where data existed) to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals' hearing and produce illumination that can be seen by many species.

  10. Camera traps can be heard and seen by animals.

    Directory of Open Access Journals (Sweden)

    Paul D Meek

    Full Text Available Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5 and infrared illumination outputs (n = 7 of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21 and assessed the vision ranges (n = 3 of mammals species (where data existed to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals' hearing and produce illumination that can be seen by many species.

  11. a Spatio-Spectral Camera for High Resolution Hyperspectral Imaging

    Science.gov (United States)

    Livens, S.; Pauly, K.; Baeck, P.; Blommaert, J.; Nuyts, D.; Zender, J.; Delauré, B.

    2017-08-01

    Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS) is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600-900 nm) in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots), horticulture (crop status monitoring to evaluate irrigation management in strawberry fields) and geology (meteorite detection on a grassland field). Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475-925 nm), and we discuss future work.

  12. Vibration factors impact analysis on aerial film camera imaging quality

    Science.gov (United States)

    Xie, Jun; Han, Wei; Xu, Zhonglin; Tan, Haifeng; Yang, Mingquan

    2017-08-01

    Aerial film camera can acquire ground target image information advantageous, but meanwhile the change of aircraft attitude, the film features and the work of camera inside system could result in a vibration which could depress the image quality greatly. This paper presented a design basis of vibration mitigation stabilized platform based on the vibration characteristic of the aerial film camera and indicated the application analysis that stabilized platform could support aerial camera to realize the shoot demand of multi-angle and large scale. According to the technique characteristics of stabilized platform, the development direction are high precision, more agility, miniaturization and low power.

  13. COMPARISON OF METHODS FOR GEOMETRIC CAMERA CALIBRATION

    Directory of Open Access Journals (Sweden)

    J. Hieronymus

    2012-09-01

    Full Text Available Methods for geometric calibration of cameras in close-range photogrammetry are established and well investigated. The most common one is based on test-fields with well-known pattern, which are observed from different directions. The parameters of a distortion model are calculated using bundle-block-adjustment-algorithms. This methods works well for short focal lengths, but is essentially more problematic to use with large focal lengths. Those would require very large test-fields and surrounding space. To overcome this problem, there is another common method for calibration used in remote sensing. It employs measurements using collimator and a goniometer. A third calibration method uses diffractive optical elements (DOE to project holograms of well known pattern. In this paper these three calibration methods are compared empirically, especially in terms of accuracy. A camera has been calibrated with those methods mentioned above. All methods provide a set of distortion correction parameters as used by the photogrammetric software Australis. The resulting parameter values are very similar for all investigated methods. The three sets of distortion parameters are crosscompared against all three calibration methods. This is achieved by inserting the gained distortion parameters as fixed input into the calibration algorithms and only adjusting the exterior orientation. The RMS (root mean square of the remaining image coordinate residuals are taken as a measure of distortion correction quality. There are differences resulting from the different calibration methods. Nevertheless the measure is small for every comparison, which means that all three calibration methods can be used for accurate geometric calibration.

  14. Overexpression of rice black-streaked dwarf virus p7-1 in Arabidopsis results in male sterility due to non-dehiscent anthers.

    Directory of Open Access Journals (Sweden)

    Feng Sun

    Full Text Available Rice black-streaked dwarf virus (RBSDV, a member of the genus Fijivirus in the family Reoviridae, is propagatively transmitted by the small brown planthopper (Laodelphax striatellus Fallén. RBSDV causes rice black-streaked dwarf and maize rough dwarf diseases, which lead to severe yield losses in crops in China. Although several RBSDV proteins have been studied in detail, the functions of the nonstructural protein P7-1 are still largely unknown. To investigate the role of the P7-1 protein in virus pathogenicity, transgenic Arabidopsis thaliana plants were generated in which the P7-1 gene was expressed under the control of the 35S promoter. The RBSDV P7-1-transgenic Arabidopsis plants (named P7-1-OE were male sterility. Flowers and pollen from P7-1-transgenic plants were of normal size and shape, and anthers developed to the normal size but failed to dehisce. The non-dehiscent anthers observed in P7-1-OE were attributed to decreased lignin content in the anthers. Furthermore, the reactive oxygen species levels were quite low in the transgenic plants compared with the wild type. These results indicate that ectopic expression of the RBSDV P7-1 protein in A. thaliana causes male sterility, possibly through the disruption of the lignin biosynthesis and H2O2-dependent polymerization pathways.

  15. Variable number of tandem repeat markers in the genome sequence of Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana (Musa spp).

    Science.gov (United States)

    Garcia, S A L; Van der Lee, T A J; Ferreira, C F; Te Lintel Hekkert, B; Zapater, M-F; Goodwin, S B; Guzmán, M; Kema, G H J; Souza, M T

    2010-11-09

    We searched the genome of Mycosphaerella fijiensis for molecular markers that would allow population genetics analysis of this plant pathogen. M. fijiensis, the causal agent of banana leaf streak disease, also known as black Sigatoka, is the most devastating pathogen attacking bananas (Musa spp). Recently, the entire genome sequence of M. fijiensis became available. We screened this database for VNTR markers. Forty-two primer pairs were selected for validation, based on repeat type and length and the number of repeat units. Five VNTR markers showing multiple alleles were validated with a reference set of isolates from different parts of the world and a population from a banana plantation in Costa Rica. Polymorphism information content values varied from 0.6414 to 0.7544 for the reference set and from 0.0400 and 0.7373 for the population set. Eighty percent of the polymorphism information content values were above 0.60, indicating that the markers are highly informative. These markers allowed robust scoring of agarose gels and proved to be useful for variability and population genetics studies. In conclusion, the strategy we developed to identify and validate VNTR markers is an efficient means to incorporate markers that can be used for fungicide resistance management and to develop breeding strategies to control banana black leaf streak disease. This is the first report of VNTR-minisatellites from the M. fijiensis genome sequence.

  16. A fast, noniterative approach for accelerated high-temporal resolution cine-CMR using dynamically interleaved streak removal in the power-spectral encoded domain with low-pass filtering (DISPEL) and modulo-prime spokes (MoPS).

    Science.gov (United States)

    Kawaji, Keigo; Patel, Mita B; Cantrell, Charles G; Tanaka, Akiko; Marino, Marco; Tamura, Satoshi; Wang, Hui; Wang, Yi; Carroll, Timothy J; Ota, Takeyoshi; Patel, Amit R

    2017-07-01

    To introduce a pair of accelerated non-Cartesian acquisition principles that when combined, exploit the periodicity of k-space acquisition, and thereby enable acquisition of high-temporal cine Cardiac Magnetic Resonance (CMR). The mathematical formulation of a noniterative, undersampled non-Cartesian cine acquisition and reconstruction is presented. First, a low-pass filtering step that exploits streaking artifact redundancy is provided (i.e., Dynamically Interleaved Streak removal in the Power-spectrum Encoded domain with Low-pass filtering [DISPEL]). Next, an effective radial acquisition for the DISPEL approach that exploits the property of prime numbers is described (i.e., Modulo-Prime Spoke [MoPS]). Both DISPEL and MoPS are examined using numerical simulation of a digital heart phantom to show that high-temporal cine-CMR is feasible without removing physiologic motion vs aperiodic interleaving using Golden Angles. The combined high-temporal cine approach is next examined in 11 healthy subjects for a time-volume curve assessment of left ventricular systolic and diastolic performance vs conventional Cartesian cine-CMR reference. The DISPEL method was first shown using simulation under different streak cycles to allow separation of undersampled radial streaking artifacts from physiologic motion with a sufficiently frequent streak-cycle interval. Radial interleaving with MoPS is next shown to allow interleaves with pseudo-Golden-Angle variants, and be more compatible with DISPEL against irrational and nonperiodic rotation angles, including the Golden-Angle-derived rotations. In the in vivo data, the proposed method showed no statistical difference in the systolic performance, while diastolic parameters sensitive to the cine's temporal resolution were statistically significant (P cine). We demonstrate a high-temporal resolution cine-CMR using DISPEL and MoPS, whose streaking artifact was separated from physiologic motion. © 2017 American Association of Physicists

  17. A tiny VIS-NIR snapshot multispectral camera

    Science.gov (United States)

    Geelen, Bert; Blanch, Carolina; Gonzalez, Pilar; Tack, Nicolaas; Lambrechts, Andy

    2015-03-01

    Spectral imaging can reveal a lot of hidden details about the world around us, but is currently confined to laboratory environments due to the need for complex, costly and bulky cameras. Imec has developed a unique spectral sensor concept in which the spectral unit is monolithically integrated on top of a standard CMOS image sensor at wafer level, hence enabling the design of compact, low cost and high acquisition speed spectral cameras with a high design flexibility. This flexibility has previously been demonstrated by imec in the form of three spectral camera architectures: firstly a high spatial and spectral resolution scanning camera, secondly a multichannel snapshot multispectral camera and thirdly a per-pixel mosaic snapshot spectral camera. These snapshot spectral cameras sense an entire multispectral data cube at one discrete point in time, extending the domain of spectral imaging towards dynamic, video-rate applications. This paper describes the integration of our per-pixel mosaic snapshot spectral sensors inside a tiny, portable and extremely user-friendly camera. Our prototype demonstrator cameras can acquire multispectral image cubes, either of 272x512 pixels over 16 bands in the VIS (470-620nm) or of 217x409 pixels over 25 bands in the VNIR (600-900nm) at 170 cubes per second for normal machine vision illumination levels. The cameras themselves are extremely compact based on Ximea xiQ cameras, measuring only 26x26x30mm, and can be operated from a laptop-based USB3 connection, making them easily deployable in very diverse environments.

  18. Coaxial visible and FIR camera system with accurate geometric calibration

    Science.gov (United States)

    Ogino, Yuka; Shibata, Takashi; Tanaka, Masayuki; Okutomi, Masatoshi

    2017-05-01

    A far-infrared (FIR) image contains important invisible information for various applications such as night vision and fire detection, while a visible image includes colors and textures in a scene. We present a coaxial visible and FIR camera system accompanied to obtain the complementary information of both images simultaneously. The proposed camera system is composed of three parts: a visible camera, a FIR camera, and a beam-splitter made from silicon. The FIR radiation from the scene is reflected at the beam-splitter, while the visible radiation is transmitted through this beam-splitter. Even if we use this coaxial visible and FIR camera system, the alignment between the visible and FIR images are not perfect. Therefore, we also present the joint calibration method which can simultaneously estimate accurate geometric parameters of both cameras, i.e. the intrinsic parameters of both cameras and the extrinsic parameters between both cameras. In the proposed calibration method, we use a novel calibration target which has a two-layer structure where thermal emission property of each layer is different. By using the proposed calibration target, we can stably and precisely obtain the corresponding points of the checker pattern in the calibration target from both the visible and the FIR images. Widely used calibration tools can accurately estimate both camera parameters. We can obtain aligned visible and FIR images by the coaxial camera system with precise calibration using two-layer calibration target. Experimental results demonstrate that the proposed camera system is useful for various applications such as image fusion, image denoising, and image up-sampling.

  19. Structure from motion with wide circular field of view cameras.

    Science.gov (United States)

    Micusík, Branislav; Pajdla, Tomás

    2006-07-01

    This paper presents a method for fully automatic and robust estimation of two-view geometry, autocalibration, and 3D metric reconstruction from point correspondences in images taken by cameras with wide circular field of view. We focus on cameras which have more than 180 degrees field of view and for which the standard perspective camera model is not sufficient, e.g., the cameras equipped with circular fish-eye lenses Nikon FC-E8 (183 degrees), Sigma 8mm-f4-EX (180 degrees), or with curved conical mirrors. We assume a circular field of view and axially symmetric image projection to autocalibrate the cameras. Many wide field of view cameras can still be modeled by the central projection followed by a nonlinear image mapping. Examples are the above-mentioned fish-eye lenses and properly assembled catadioptric cameras with conical mirrors. We show that epipolar geometry of these cameras can be estimated from a small number of correspondences by solving a polynomial eigenvalue problem. This allows the use of efficient RANSAC robust estimation to find the image projection model, the epipolar geometry, and the selection of true point correspondences from tentative correspondences contaminated by mismatches. Real catadioptric cameras are often slightly noncentral. We show that the proposed autocalibration with approximate central models is usually good enough to get correct point correspondences which can be used with accurate noncentral models in a bundle adjustment to obtain accurate 3D scene reconstruction. Noncentral camera models are dealt with and results are shown for catadioptric cameras with parabolic and spherical mirrors.

  20. A comparison of camera trap and permanent recording video camera efficiency in wildlife underpasses.

    Science.gov (United States)

    Jumeau, Jonathan; Petrod, Lana; Handrich, Yves

    2017-09-01

    In the current context of biodiversity loss through habitat fragmentation, the effectiveness of wildlife crossings, installed at great expense as compensatory measures, is of vital importance for ecological and socio-economic actors. The evaluation of these structures is directly impacted by the efficiency of monitoring tools (camera traps…), which are used to assess the effectiveness of these crossings by observing the animals that use them. The aim of this study was to quantify the efficiency of camera traps in a wildlife crossing evaluation. Six permanent recording video systems sharing the same field of view as six Reconyx HC600 camera traps installed in three wildlife underpasses were used to assess the exact proportion of missed events (event being the presence of an animal within the field of view), and the error rate concerning underpass crossing behavior (defined as either Entry or Refusal). A sequence of photographs was triggered by either animals (true trigger) or artefacts (false trigger). We quantified the number of false triggers that had actually been caused by animals that were not visible on the images ("false" false triggers). Camera traps failed to record 43.6% of small mammal events (voles, mice, shrews, etc.) and 17% of medium-sized mammal events. The type of crossing behavior (Entry or Refusal) was incorrectly assessed in 40.1% of events, with a higher error rate for entries than for refusals. Among the 3.8% of false triggers, 85% of them were "false" false triggers. This study indicates a global underestimation of the effectiveness of wildlife crossings for small mammals. Means to improve the efficiency are discussed.

  1. Vision System of Mobile Robot Combining Binocular and Depth Cameras

    Directory of Open Access Journals (Sweden)

    Yuxiang Yang

    2017-01-01

    Full Text Available In order to optimize the three-dimensional (3D reconstruction and obtain more precise actual distances of the object, a 3D reconstruction system combining binocular and depth cameras is proposed in this paper. The whole system consists of two identical color cameras, a TOF depth camera, an image processing host, a mobile robot control host, and a mobile robot. Because of structural constraints, the resolution of TOF depth camera is very low, which difficultly meets the requirement of trajectory planning. The resolution of binocular stereo cameras can be very high, but the effect of stereo matching is not ideal for low-texture scenes. Hence binocular stereo cameras also difficultly meet the requirements of high accuracy. In this paper, the proposed system integrates depth camera and stereo matching to improve the precision of the 3D reconstruction. Moreover, a double threads processing method is applied to improve the efficiency of the system. The experimental results show that the system can effectively improve the accuracy of 3D reconstruction, identify the distance from the camera accurately, and achieve the strategy of trajectory planning.

  2. Camera Layout Design for the Upper Stage Thrust Cone

    Science.gov (United States)

    Wooten, Tevin; Fowler, Bart

    2010-01-01

    Engineers in the Integrated Design and Analysis Division (EV30) use a variety of different tools to aid in the design and analysis of the Ares I vehicle. One primary tool in use is Pro-Engineer. Pro-Engineer is a computer-aided design (CAD) software that allows designers to create computer generated structural models of vehicle structures. For the Upper State thrust cone, Pro-Engineer was used to assist in the design of a layout for two camera housings. These cameras observe the separation between the first and second stage of the Ares I vehicle. For the Ares I-X, one standard speed camera was used. The Ares I design calls for two separate housings, three cameras, and a lighting system. With previous design concepts and verification strategies in mind, a new layout for the two camera design concept was developed with members of the EV32 team. With the new design, Pro-Engineer was used to draw the layout to observe how the two camera housings fit with the thrust cone assembly. Future analysis of the camera housing design will verify the stability and clearance of the camera with other hardware present on the thrust cone.

  3. It's a Snap! Selecting the Right Digital Camera

    Science.gov (United States)

    Browne, Ron

    2005-01-01

    Digital cameras can be wonderful teaching/learning tools in the preschool classroom. They can record and document student development, make text-free cues for pre-reading children, and develop learning prompts for discussion. In this article, the author discusses tips on selecting the right digital camera. Above all, it is important to consider…

  4. Improving photometric calibration of meteor video camera systems

    Science.gov (United States)

    Ehlert, Steven; Kingery, Aaron; Suggs, Robert

    2017-09-01

    We present the results of new calibration tests performed by the NASA Meteoroid Environment Office (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the first point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric flux within the camera bandpass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at ∼ 0.20 mag , and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to ∼ 0.05 - 0.10 mag in both filtered and unfiltered camera observations with no evidence for lingering systematics. These improvements are essential to accurately measuring photometric masses of individual meteors and source mass indexes.

  5. Finding suspects in multiple cameras for improved railway protection

    NARCIS (Netherlands)

    Marck, J.W.; Bouma, H.; Baan, J; Oliveira Filho, J. de; Brink, M. van der

    2014-01-01

    The capability to find individuals using CCTV cameras is important for surveillance applications at large areas such as railway stations, airports and shopping centers. However, it is laborious to track and trace people over multiple cameras post incident. In this paper, we describe the live

  6. Measurement of the nonuniformity of first responder thermal imaging cameras

    Science.gov (United States)

    Lock, Andrew; Amon, Francine

    2008-04-01

    Police, firefighters, and emergency medical personnel are examples of first responders that are utilizing thermal imaging cameras in a very practical way every day. However, few performance metrics have been developed to assist first responders in evaluating the performance of thermal imaging technology. This paper describes one possible metric for evaluating the nonuniformity of thermal imaging cameras. Several commercially available uncooled focal plane array cameras were examined. Because of proprietary property issues, each camera was considered a 'black box'. In these experiments, an extended area black body (18 cm square) was placed very close to the objective lens of the thermal imaging camera. The resultant video output from the camera was digitized at a resolution of 640x480 pixels and a grayscale depth of 10 bits. The nonuniformity was calculated using the standard deviation of the digitized image pixel intensities divided by the mean of those pixel intensities. This procedure was repeated for each camera at several blackbody temperatures in the range from 30° C to 260° C. It has observed that the nonuniformity initially increases with temperature, then asymptotically approaches a maximum value. Nonuniformity is also applied to the calculation of Spatial Frequency Response as well providing a noise floor. The testing procedures described herein are being developed as part of a suite of tests to be incorporated into a performance standard covering thermal imaging cameras for first responders.

  7. CALIBRATION OF LOW COST RGB AND NIR UAV CAMERAS

    Directory of Open Access Journals (Sweden)

    A. Fryskowska

    2016-06-01

    Full Text Available Non-metric digital cameras are being widely used for photogrammetric studies. The increase in resolution and quality of images obtained by non-metric cameras, allows to use it in low-cost UAV and terrestrial photogrammetry. Imagery acquired with non-metric cameras can be used in 3D modeling of objects or landscapes, reconstructing of historical sites, generating digital elevation models (DTM, orthophotos, or in the assessment of accidents. Non-metric digital camcorders are characterized by instability and ignorance of the interior orientation parameters. Therefore, the use of these devices requires prior calibration. Calibration research was conducted using non-metric camera, different calibration tests and various software. The first part of the paper contains a brief theoretical introduction including the basic definitions, like the construction of non-metric cameras or description of different optical distortions. The second part of the paper contains cameras calibration process, details of the calibration methods and models that have been used. Sony Nex 5 camera calibration has been done using software: Image Master Calib, Matlab - Camera Calibrator application and Agisoft Lens. For the study 2D test fields has been used. As a part of the research a comparative analysis of the results have been done.

  8. Imaging Emission Spectra with Handheld and Cellphone Cameras

    Science.gov (United States)

    Sitar, David

    2012-01-01

    As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboratory setting on a shoestring budget and get immediate results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon…

  9. The Camera Never Lies? Photographic Research Methods in Human Geography

    Science.gov (United States)

    Hall, Tim

    2009-01-01

    A camera is an essential tool for human geography students. Most students come back from an overseas fieldtrip, for example, with their camera crammed with images captured on the hoof around their destination. Many of these will find their way into essays, reports and presentations. Photographs are also typically a key element of many human…

  10. A color based rangefinder for an omnidirectional camera

    NARCIS (Netherlands)

    Nguyen, Q.; Visser, A.; Balakirsky, S.; Carpin, S.; Lewis, M.

    2009-01-01

    This paper proposes a method to use the omnidirectional camera as a rangefinder by using color detection. The omnicam rangefinder has been tested in USARSim for its accuracy and for its practical use to build maps of the environment. The results of the test shows that an omnidirectional camera can

  11. Students' Framing of Laboratory Exercises Using Infrared Cameras

    Science.gov (United States)

    Haglund, Jesper; Jeppsson, Fredrik; Hedberg, David; Schönborn, Konrad J.

    2015-01-01

    Thermal science is challenging for students due to its largely imperceptible nature. Handheld infrared cameras offer a pedagogical opportunity for students to see otherwise invisible thermal phenomena. In the present study, a class of upper secondary technology students (N = 30) partook in four IR-camera laboratory activities, designed around the…

  12. Raspberry Pi camera with intervalometer used as crescograph

    Science.gov (United States)

    Albert, Stefan; Surducan, Vasile

    2017-12-01

    The intervalometer is an attachment or facility on a photo-camera that operates the shutter regularly at set intervals over a period. Professional cameras with built in intervalometers are expensive and quite difficult to find. The Canon CHDK open source operating system allows intervalometer implementation on Canon cameras only. However finding a Canon camera with near infra-red (NIR) photographic lens at affordable price is impossible. On experiments requiring several cameras (used to measure growth in plants - the crescographs, but also for coarse evaluation of the water content of leaves), the costs of the equipment are often over budget. Using two Raspberry Pi modules each equipped with a low cost NIR camera and a WIFI adapter (for downloading pictures stored on the SD card) and some freely available software, we have implemented two low budget intervalometer cameras. The shutting interval, the number of pictures to be taken, image resolution and some other parameters can be fully programmed. Cameras have been in use continuously for three months (July-October 2017) in a relevant environment (outside), proving the concept functionality.

  13. A Simple Spectrophotometer Using Common Materials and a Digital Camera

    Science.gov (United States)

    Widiatmoko, Eko; Widayani; Budiman, Maman; Abdullah, Mikrajuddin; Khairurrijal

    2011-01-01

    A simple spectrophotometer was designed using cardboard, a DVD, a pocket digital camera, a tripod and a computer. The DVD was used as a diffraction grating and the camera as a light sensor. The spectrophotometer was calibrated using a reference light prior to use. The spectrophotometer was capable of measuring optical wavelengths with a…

  14. Development of camera technology for monitoring nests. Chapter 15

    Science.gov (United States)

    W. Andrew Cox; M. Shane Pruett; Thomas J. Benson; Scott J. Chiavacci; Frank R., III Thompson

    2012-01-01

    Photo and video technology has become increasingly useful in the study of avian nesting ecology. However, researchers interested in using camera systems are often faced with insufficient information on the types and relative advantages of available technologies. We reviewed the literature for studies of nests that used cameras and summarized them based on study...

  15. Camera monologue: Cultural critique beyond collaboration, participation, and dialogue

    DEFF Research Database (Denmark)

    Suhr, Christian

    2018-01-01

    Cameras always seem to capture a little too little and a little too much. In ethnographic films, profound insights are often found in the tension between what we are socially taught to perceive, and the peculiar non-social perception of the camera. Ethnographic filmmakers study the worlds of huma...

  16. Camera Control and Geo-Registration for Video Sensor Networks

    Science.gov (United States)

    Davis, James W.

    With the use of large video networks, there is a need to coordinate and interpret the video imagery for decision support systems with the goal of reducing the cognitive and perceptual overload of human operators. We present computer vision strategies that enable efficient control and management of cameras to effectively monitor wide-coverage areas, and examine the framework within an actual multi-camera outdoor urban video surveillance network. First, we construct a robust and precise camera control model for commercial pan-tilt-zoom (PTZ) video cameras. In addition to providing a complete functional control mapping for PTZ repositioning, the model can be used to generate wide-view spherical panoramic viewspaces for the cameras. Using the individual camera control models, we next individually map the spherical panoramic viewspace of each camera to a large aerial orthophotograph of the scene. The result provides a unified geo-referenced map representation to permit automatic (and manual) video control and exploitation of cameras in a coordinated manner. The combined framework provides new capabilities for video sensor networks that are of significance and benefit to the broad surveillance/security community.

  17. Seeing elements by visible-light digital camera.

    Science.gov (United States)

    Zhao, Wenyang; Sakurai, Kenji

    2017-03-31

    A visible-light digital camera is used for taking ordinary photos, but with new operational procedures it can measure the photon energy in the X-ray wavelength region and therefore see chemical elements. This report describes how one can observe X-rays by means of such an ordinary camera - The front cover of the camera is replaced by an opaque X-ray window to block visible light and to allow X-rays to pass; the camera takes many snap shots (called single-photon-counting mode) to record every photon event individually; an integrated-filtering method is newly proposed to correctly retrieve the energy of photons from raw camera images. Finally, the retrieved X-ray energy-dispersive spectra show fine energy resolution and great accuracy in energy calibration, and therefore the visible-light digital camera can be applied to routine X-ray fluorescence measurement to analyze the element composition in unknown samples. In addition, the visible-light digital camera is promising in that it could serve as a position sensitive X-ray energy detector. It may become able to measure the element map or chemical diffusion in a multi-element system if it is fabricated with external X-ray optic devices. Owing to the camera's low expense and fine pixel size, the present method will be widely applied to the analysis of chemical elements as well as imaging.

  18. Demonstrations of Optical Spectra with a Video Camera

    Science.gov (United States)

    Kraftmakher, Yaakov

    2012-01-01

    The use of a video camera may markedly improve demonstrations of optical spectra. First, the output electrical signal from the camera, which provides full information about a picture to be transmitted, can be used for observing the radiant power spectrum on the screen of a common oscilloscope. Second, increasing the magnification by the camera…

  19. 28 CFR 68.42 - In camera and protective orders.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false In camera and protective orders. 68.42 Section 68.42 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) RULES OF PRACTICE AND PROCEDURE... In camera and protective orders. (a) Privileged communications. Upon application of any person, the...

  20. 32 CFR 813.4 - Combat camera operations.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Combat camera operations. 813.4 Section 813.4 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE SALES AND SERVICES VISUAL INFORMATION DOCUMENTATION PROGRAM § 813.4 Combat camera operations. (a) Air Force COMCAM forces document Air...