Noninvasive enhanced mid-IR imaging of breast cancer development in vivo

Science.gov (United States)

Case, Jason R.; Young, Madison A.; Dréau, D.; Trammell, Susan R.

2015-11-01

Lumpectomy coupled with radiation therapy and/or chemotherapy is commonly used to treat breast cancer patients. We are developing an enhanced thermal IR imaging technique that has the potential to provide real-time imaging to guide tissue excision during a lumpectomy by delineating tumor margins. This enhanced thermal imaging method is a combination of IR imaging (8 to 10 μm) and selective heating of blood (˜0.5°C) relative to surrounding water-rich tissue using LED sources at low powers. Postacquisition processing of these images highlights temporal changes in temperature and the presence of vascular structures. In this study, fluorescent, standard thermal, and enhanced thermal imaging modalities, as well as physical caliper measurements, were used to monitor breast cancer tumor volumes over a 30-day study period in 19 mice implanted with 4T1-RFP tumor cells. Tumor volumes calculated from fluorescent imaging follow an exponential growth curve for the first 22 days of the study. Cell necrosis affected the tumor volume estimates based on the fluorescent images after day 22. The tumor volumes estimated from enhanced thermal imaging, standard thermal imaging, and caliper measurements all show exponential growth over the entire study period. A strong correlation was found between tumor volumes estimated using fluorescent imaging, standard IR imaging, and caliper measurements with enhanced thermal imaging, indicating that enhanced thermal imaging monitors tumor growth. Further, the enhanced IR images reveal a corona of bright emission along the edges of the tumor masses associated with the tumor margin. In the future, this IR technique might be used to estimate tumor margins in real time during surgical procedures.

High-resolution mid-IR spectrometer based on frequency upconversion

DEFF Research Database (Denmark)

Hu, Qi; Dam, Jeppe Seidelin; Pedersen, Christian

2012-01-01

We demonstrate a novel approach for high-resolution spectroscopy based on frequency upconversion and postfiltering by means of a scanning Fabryx2013;Perot interferometer. The system is based on sum-frequency mixing, shifting the spectral content from the mid-infrared to the near-visible region al......-frequency 1064xA0;nm laser. We investigate water vapor emission lines from a butane burner and compare the measured results to model data. The presented method we suggest to be used for real-time monitoring of specific gas lines and reference signals....

Multiplexing of spatial modes in the mid-IR region

Science.gov (United States)

Gailele, Lucas; Maweza, Loyiso; Dudley, Angela; Ndagano, Bienvenu; Rosales-Guzman, Carmelo; Forbes, Andrew

2017-02-01

Traditional optical communication systems optimize multiplexing in polarization and wavelength both trans- mitted in fiber and free-space to attain high bandwidth data communication. Yet despite these technologies, we are expected to reach a bandwidth ceiling in the near future. Communications using orbital angular momentum (OAM) carrying modes offers infinite dimensional states, providing means to increase link capacity by multiplexing spatially overlapping modes in both the azimuthal and radial degrees of freedom. OAM modes are multiplexed and de-multiplexed by the use of spatial light modulators (SLM). Implementation of complex amplitude modulation is employed on laser beams phase and amplitude to generate Laguerre-Gaussian (LG) modes. Modal decomposition is employed to detect these modes due to their orthogonality as they propagate in space. We demonstrate data transfer by sending images as a proof-of concept in a lab-based scheme. We demonstrate the creation and detection of OAM modes in the mid-IR region as a precursor to a mid-IR free-space communication link.

Data fusion of Landsat TM and IRS images in forest classification

Science.gov (United States)

Guangxing Wang; Markus Holopainen; Eero Lukkarinen

2000-01-01

Data fusion of Landsat TM images and Indian Remote Sensing satellite panchromatic image (IRS-1C PAN) was studied and compared to the use of TM or IRS image only. The aim was to combine the high spatial resolution of IRS-1C PAN to the high spectral resolution of Landsat TM images using a data fusion algorithm. The ground truth of the study was based on a sample of 1,020...

High-resolution focal plane array IR detection modules and digital signal processing technologies at AIM

Science.gov (United States)

Cabanski, Wolfgang A.; Breiter, Rainer; Koch, R.; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann; Eberhardt, Kurt; Oelmaier, Reinhard; Schneider, Harald; Walther, Martin

2000-07-01

Full video format focal plane array (FPA) modules with up to 640 X 512 pixels have been developed for high resolution imaging applications in either mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) or platinum silicide (PtSi) and quantum well infrared photodetector (QWIP) technology as low cost alternatives to MCT for high performance IR imaging in the MWIR or long wave spectral band (LWIR). For the QWIP's, a new photovoltaic technology was introduced for improved NETD performance and higher dynamic range. MCT units provide fast frame rates > 100 Hz together with state of the art thermal resolution NETD hardware platforms and software for image visualization and nonuniformity correction including scene based self learning algorithms had to be developed to accomplish for the high data rates of up to 18 M pixels/s with 14-bit deep data, allowing to take into account nonlinear effects to access the full NETD by accurate reduction of residual fixed pattern noise. The main features of these modules are summarized together with measured performance data for long range detection systems with moderately fast to slow F-numbers like F/2.0 - F/3.5. An outlook shows most recent activities at AIM, heading for multicolor and faster frame rate detector modules based on MCT devices.

Mid-IR hyperspectral imaging for label-free histopathology and cytology

DEFF Research Database (Denmark)

Hermes, M.; Morrish, R. Brandstrup; Huot, Laurent

2018-01-01

Mid-infrared (MIR) imaging has emerged as a valuable tool to investigate biological samples, such as tissue histological sections and cell cultures, by providing non-destructive chemical specificity without recourse to labels. While feasibility studies have shown the capabilities of MIR imaging a...

Image transmission in mid-IR using a solid state laser pumped optical parametric oscillator

Science.gov (United States)

Prasad, Narasimha S.; Kratovil, Pat; Magee, James R.

2002-04-01

In this paper, image transmission using a mid-wave IR (MWIR) optical transceiver based free-space data link under low visibility conditions is presented. The all-solid-state MWIR transceiver primarily consisted of a passively Q-switched, short-pulsed Nd:YAG laser pumping a periodically poled lithium niobate (PPLN) based optical parametric oscillator and a Dember effect detector. The MILES transceiver generates pulse position waveforms. The optical data link consisting of transmitter drive electronics, pulse conditioning electronics and a computer generating pulses compatible with the 2400-baud rate RS232 receiver was utilized. Data formatting and RS232 transmission and reception were achieved using a computer. Data formatting transformed an arbitrary image file format compatible with the basic operation of pump laser. Images were transmitted at a date rate of 2400 kbits/sec with 16 bits/pixel. Test images consisting of 50X40 pixels and 100X80 pixels were transmitted through free-space filled with light fog up to 120 ft. Besides optical parametric oscillators, the proposed concept can be extended to optical parametric amplifiers, Raman lasers and other nonlinear optical devices to achieve multi-functionality.

Time-domain SFG spectroscopy using mid-IR pulse shaping: practical and intrinsic advantages.

Science.gov (United States)

Laaser, Jennifer E; Xiong, Wei; Zanni, Martin T

2011-03-24

Sum-frequency generation (SFG) spectroscopy is a ubiquitous tool in the surface sciences. It provides infrared transition frequencies and line shapes that probe the structure and environment of molecules at interfaces. In this article, we apply techniques learned from the multidimensional spectroscopy community to SFG spectroscopy. We implement balanced heterodyne detection to remove scatter and the local oscillator background. Heterodyning also separates the resonant and nonresonant signals by acquiring both the real and imaginary parts of the spectrum. We utilize mid-IR pulse shaping to control the phase and delay of the mid-IR pump pulse. Pulse shaping allows phase cycling for data collection in the rotating frame and additional background subtraction. We also demonstrate time-domain data collection, which is a Fourier transform technique, and has many advantages in signal throughput, frequency resolution, and line shape accuracy over existing frequency domain methods. To demonstrate time-domain SFG spectroscopy, we study an aryl isocyanide on gold, and find that the system has an inhomogeneous structural distribution, in agreement with computational results, but which was not resolved by previous frequency-domain SFG studies. The ability to rapidly and actively manipulate the mid-IR pulse in an SFG pules sequence makes possible new experiments and more accurate spectra. © 2011 American Chemical Society

Mid-infrared nonlinear upconversion imaging and sensing

DEFF Research Database (Denmark)

Pedersen, Christian; Tidemand-Lichtenberg, Peter

2016-01-01

The mid-IR wavelength range is highly relevant for a number of applications related to gas spectroscopy and spectral analysis of complex molecules such as those including CH bounds. The main obstacles for exploitation of mid-IR applications include suitable and affordable mid-IR light sources...

The design and application of a multi-band IR imager

Science.gov (United States)

Li, Lijuan

2018-02-01

Multi-band IR imaging system has many applications in security, national defense, petroleum and gas industry, etc. So the relevant technologies are getting more and more attention in rent years. As we know, when used in missile warning and missile seeker systems, multi-band IR imaging technology has the advantage of high target recognition capability and low false alarm rate if suitable spectral bands are selected. Compared with traditional single band IR imager, multi-band IR imager can make use of spectral features in addition to space and time domain features to discriminate target from background clutters and decoys. So, one of the key work is to select the right spectral bands in which the feature difference between target and false target is evident and is well utilized. Multi-band IR imager is a useful instrument to collect multi-band IR images of target, backgrounds and decoys for spectral band selection study at low cost and with adjustable parameters and property compared with commercial imaging spectrometer. In this paper, a multi-band IR imaging system is developed which is suitable to collect 4 spectral band images of various scenes at every turn and can be expanded to other short-wave and mid-wave IR spectral bands combination by changing filter groups. The multi-band IR imaging system consists of a broad band optical system, a cryogenic InSb large array detector, a spinning filter wheel and electronic processing system. The multi-band IR imaging system's performance is tested in real data collection experiments.

Adding a dimension to the infrared spectra of interfaces: 2D SFG spectroscopy via mid-IR pulse shaping

Science.gov (United States)

Zanni, Martin

2012-02-01

Sum-frequency generation spectroscopy provides an infrared spectrum of interfaces and thus has widespread use in the materials and chemical sciences. In this presentation, I will present our recent work in developing a 2D pulse sequence to generate 2D SFG spectra of interfaces, in analogy to 2D infrared spectra used to measure bulk species. To develop this spectroscopy, we have utilized many of the tricks-of-the-trade developed in the 2D IR and 2D Vis communities in the last decade, including mid-IR pulse shaping. With mid-IR pulse shaping, the 2D pulse sequence is manipulated by computer programming in the desired frequency resolution, rotating frame, and signal pathway. We believe that 2D SFG will become an important tool in the interfacial sciences in an analogous way that 2D IR is now being used in many disciplines.

Archival Investigation of Outburst Sites and Progenitors of Extragalactic Intermediate-Luminosity Mid-IR Transients

Science.gov (United States)

Bond, Howard

2017-08-01

Our team is using Spitzer in a long-term search for extragalactic mid-infrared (MIR) variable stars and transients-the SPIRITS project (SPitzer InfraRed Intensive Transients Survey). In this first exploration of luminous astrophysical transients in the infrared, we have discovered a puzzling new class. We call them SPRITEs: eSPecially Red Intermediate-luminosity Transient Events. They have maximum MIR luminosities between supernovae and classical novae, but are not detected in the optical to deep limits. To date, we have discovered more than 50 SPRITEs in galaxies out to 17 Mpc. In this Archival Research proposal, we request support in order to investigate the pre-eruption sites in HST images of some 3 dozen SPRITEs discovered to date, and an additional 2 dozen that we are likely to find until the end of Spitzer observing in late 2018. Our aims are (1) characterize the pre-outburst environments at HST resolution in the visible and near-IR, to understand the stellar populations, stellar ages and masses, and interstellar medium at the outburst sites; (2) search for progenitors; (3) help prepare the way for a better understanding of the nature of extragalactic IR transients that will be investigated by JWST.

Mid-IR laser system for advanced neurosurgery

Science.gov (United States)

Klosner, M.; Wu, C.; Heller, D. F.

2014-03-01

We present work on a laser system operating in the near- and mid-IR spectral regions, having output characteristics designed to be optimal for cutting various tissue types. We provide a brief overview of laser-tissue interactions and the importance of controlling certain properties of the light beam. We describe the principle of operation of the laser system, which is generally based on a wavelength-tunable alexandrite laser oscillator/amplifier, and multiple Raman conversion stages. This configuration provides robust access to the mid-IR spectral region at wavelengths, pulse energies, pulse durations, and repetition rates that are attractive for neurosurgical applications. We summarize results for ultra-precise selective cutting of nerve sheaths and retinas with little collateral damage; this has applications in procedures such as optic-nerve-sheath fenestration and possible spinal repair. We also report results for cutting cornea, and dermal tissues.

A Modified Harris Corner Detection for Breast IR Image

Directory of Open Access Journals (Sweden)

Chia-Yen Lee

2014-01-01

Full Text Available Harris corner detectors, which depend on strong invariance and a local autocorrelation function, display poor detection performance for infrared (IR images with low contrast and nonobvious edges. In addition, feature points detected by Harris corner detectors are clustered due to the numerous nonlocal maxima. This paper proposes a modified Harris corner detector that includes two unique steps for processing IR images in order to overcome the aforementioned problems. Image contrast enhancement based on a generalized form of histogram equalization (HE combined with adjusting the intensity resolution causes false contours on IR images to acquire obvious edges. Adaptive nonmaximal suppression based on eliminating neighboring pixels avoids the clustered features. Preliminary results show that the proposed method can solve the clustering problem and successfully identify the representative feature points of IR breast images.

TESTING THE HYPOTHESIS THAT METHANOL MASER RINGS TRACE CIRCUMSTELLAR DISKS: HIGH-RESOLUTION NEAR-INFRARED AND MID-INFRARED IMAGING

International Nuclear Information System (INIS)

De Buizer, James M.; Bartkiewicz, Anna; Szymczak, Marian

2012-01-01

Milliarcsecond very long baseline interferometry maps of regions containing 6.7 GHz methanol maser emission have lead to the recent discovery of ring-like distributions of maser spots and the plausible hypothesis that they may be tracing circumstellar disks around forming high-mass stars. We aimed to test this hypothesis by imaging these regions in the near- and mid-infrared at high spatial resolution and compare the observed emission to the expected infrared morphologies as inferred from the geometries of the maser rings. In the near-infrared we used the Gemini North adaptive optics system of ALTAIR/NIRI, while in the mid-infrared we used the combination of the Gemini South instrument T-ReCS and super-resolution techniques. Resultant images had a resolution of ∼150 mas in both the near-infrared and mid-infrared. We discuss the expected distribution of circumstellar material around young and massive accreting (proto)stars and what infrared emission geometries would be expected for the different maser ring orientations under the assumption that the masers are coming from within circumstellar disks. Based upon the observed infrared emission geometries for the four targets in our sample and the results of spectral energy distribution modeling of the massive young stellar objects associated with the maser rings, we do not find compelling evidence in support of the hypothesis that methanol masers rings reside in circumstellar disks.

Characterization of a novel miniaturized burst-mode infrared laser system for IR-MALDESI mass spectrometry imaging.

Science.gov (United States)

Ekelöf, Måns; Manni, Jeffrey; Nazari, Milad; Bokhart, Mark; Muddiman, David C

2018-03-01

Laser systems are widely used in mass spectrometry as sample probes and ionization sources. Mid-infrared lasers are particularly suitable for analysis of high water content samples such as animal and plant tissues, using water as a resonantly excited sacrificial matrix. Commercially available mid-IR lasers have historically been bulky and expensive due to cooling requirements. This work presents a novel air-cooled miniature mid-IR laser with adjustable burst-mode output and details an evaluation of its performance for mass spectrometry imaging. The miniature laser was found capable of generating sufficient energy for complete ablation of animal tissue in the context of an IR-MALDESI experiment with exogenously added ice matrix, yielding several hundred confident metabolite identifications. Graphical abstract The use of a novel miniature 2.94 μm burst-mode laser in IR-MALDESI allows for rapid and sensitive mass spectrometry imaging of a whole mouse.

Invited Article: Multiple-octave spanning high-energy mid-IR supercontinuum generation in bulk quadratic nonlinear crystals

Directory of Open Access Journals (Sweden)

Binbin Zhou

2016-08-01

Full Text Available Bright and broadband coherent mid-IR radiation is important for exciting and probing molecular vibrations. Using cascaded nonlinearities in conventional quadratic nonlinear crystals like lithium niobate, self-defocusing near-IR solitons have been demonstrated that led to very broadband supercontinuum generation in the visible, near-IR, and short-wavelength mid-IR. Here we conduct an experiment where a mid-IR crystal is pumped in the mid-IR. The crystal is cut for noncritical interaction, so the three-wave mixing of a single mid-IR femtosecond pump source leads to highly phase-mismatched second-harmonic generation. This self-acting cascaded process leads to the formation of a self-defocusing soliton at the mid-IR pump wavelength and after the self-compression point multiple octave-spanning supercontinua are observed. The results were recorded in a commercially available crystal LiInS2 pumped in the 3-4 μm range with 85 fs 50 μJ pulse energy, with the broadest supercontinuum covering 1.6-7.0 μm. We measured up 30 μJ energy in the supercontinuum, and the energy promises to scale favorably with an increased pump energy. Other mid-IR crystals can readily be used as well to cover other pump wavelengths and target other supercontinuum wavelength ranges.

Mid-Infrared Spectral Properties of IR QSOs

International Nuclear Information System (INIS)

Xia, X. Y.; Cao, C.; Mao, S.; Deng, Z. G.

2008-01-01

We analyse mid-infrared (MIR) spectroscopic properties for 19 ultra-luminous infrared quasars (IR QSOs) in the local universe based on the spectra from the Infrared Spectrograph on board the Spitzer Space Telescope. The MIR properties of IR QSOs are compared with those of optically-selected Palomar-Green QSOs (PG QSOs) and ultra-luminous infrared galaxies (ULIRGs). The average MIR spectral features from ∼5 to 30 μm, including the spectral slopes, 6.2 μm PAH emission strengths and [NeII] 12.81 μm luminosities of IR QSOs, differ from those of PG QSOs. In contrast, IR QSOs and ULIRGs have comparable PAH and [NeII] luminosities. These results are consistent with IR QSOs being at a transitional stage from ULIRGs to classical QSOs. We also find the correlation between the EW (PAH 6.2 μm) and outflow velocities suggests that star formation activities are suppressed by feedback from AGNs and/or supernovae.

Mid-IR Properties of an Unbiased AGN Sample of the Local Universe. 1; Emission-Line Diagnostics

Science.gov (United States)

Weaver, K. A.; Melendez, M.; Muhotzky, R. F.; Kraemer, S.; Engle, K.; Malumuth. E.; Tueller, J.; Markwardt, C.; Berghea, C. T.; Dudik, R. P.;

Multi-Sensor Fusion of Infrared and Electro-Optic Signals for High Resolution Night Images

Directory of Open Access Journals (Sweden)

Victor Lawrence

2012-07-01

Full Text Available Electro-optic (EO image sensors exhibit the properties of high resolution and low noise level at daytime, but they do not work in dark environments. Infrared (IR image sensors exhibit poor resolution and cannot separate objects with similar temperature. Therefore, we propose a novel framework of IR image enhancement based on the information (e.g., edge from EO images, which improves the resolution of IR images and helps us distinguish objects at night. Our framework superimposing/blending the edges of the EO image onto the corresponding transformed IR image improves their resolution. In this framework, we adopt the theoretical point spread function (PSF proposed by Hardie et al. for the IR image, which has the modulation transfer function (MTF of a uniform detector array and the incoherent optical transfer function (OTF of diffraction-limited optics. In addition, we design an inverse filter for the proposed PSF and use it for the IR image transformation. The framework requires four main steps: (1 inverse filter-based IR image transformation; (2 EO image edge detection; (3 registration; and (4 blending/superimposing of the obtained image pair. Simulation results show both blended and superimposed IR images, and demonstrate that blended IR images have better quality over the superimposed images. Additionally, based on the same steps, simulation result shows a blended IR image of better quality when only the original IR image is available.

Upconversion imager measures single mid-IR photons

DEFF Research Database (Denmark)

Dam, Jeppe Seidelin; Tidemand-Lichtenberg, Peter; Pedersen, Christian

2013-01-01

the performance of today's state of the art IR detectors for the visible/near-IR region shows a striking contrast, as the latter can have dark currents in the range of 0.001 electrons per second. Demonstrated performance of waveguide upconversion techniques still show considerable dark noise, even when working...

Submillisecond mixing in a continuous-flow, microfluidic mixer utilizing mid-infrared hyperspectral imaging detection.

Science.gov (United States)

Kise, Drew P; Magana, Donny; Reddish, Michael J; Dyer, R Brian

2014-02-07

We report a continuous-flow, microfluidic mixer utilizing mid-infrared hyperspectral imaging detection, with an experimentally determined, submillisecond mixing time. The simple and robust mixer design has the microfluidic channels cut through a polymer spacer that is sandwiched between two IR transparent windows. The mixer hydrodynamically focuses the sample stream with two side flow channels, squeezing it into a thin jet and initiating mixing through diffusion and advection. The detection system generates a mid-infrared hyperspectral absorbance image of the microfluidic sample stream. Calibration of the hyperspectral image yields the mid-IR absorbance spectrum of the sample versus time. A mixing time of 269 μs was measured for a pD jump from 3.2 to above 4.5 in a D2O sample solution of adenosine monophosphate (AMP), which acts as an infrared pD indicator. The mixer was further characterized by comparing experimental results with a simulation of the mixing of an H2O sample stream with a D2O sheath flow, showing good agreement between the two. The IR microfluidic mixer eliminates the need for fluorescence labeling of proteins with bulky, interfering dyes, because it uses the intrinsic IR absorbance of the molecules of interest, and the structural specificity of IR spectroscopy to follow specific chemical changes such as the protonation state of AMP.

FIRST SCIENCE RESULTS FROM SOFIA/FORCAST: SUPER-RESOLUTION IMAGING OF THE S140 CLUSTER AT 37 {mu}m

Energy Technology Data Exchange (ETDEWEB)

Harvey, Paul M. [Astronomy Department, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Adams, Joseph D.; Herter, Terry L.; Gull, George; Schoenwald, Justin, E-mail: pmh@astro.as.utexas.edu, E-mail: jdadams@astro.cornell.edu, E-mail: tlh10@cornell.edu, E-mail: geg3@cornell.edu, E-mail: jps10@cornell.edu [Center for Radiophysics and Space Research, Space Science Building, Cornell University, Ithaca, NY 14853 (United States); and others

2012-04-20

We present 37 {mu}m imaging of the S140 complex of infrared sources centered on IRS1 made with the FORCAST camera on SOFIA. These observations are the longest wavelength imaging to resolve clearly the three main sources seen at shorter wavelengths, IRS 1, 2, and 3, and are nearly at the diffraction limit of the 2.5 m telescope. We also obtained a small number of images at 11 and 31 {mu}m that are useful for flux measurement. Our images cover the area of several strong submillimeter sources seen in the area-SMM 1, 2, and 3-that are not coincident with any mid-infrared sources and are not visible in our longer wavelength imaging either. Our new observations confirm previous estimates of the relative dust optical depth and source luminosity for the components in this likely cluster of early B stars. We also investigate the use of super-resolution to go beyond the basic diffraction limit in imaging on SOFIA and find that the van Cittert algorithm, together with the 'multi-resolution' technique, provides excellent results.

LENS MODELS OF HERSCHEL-SELECTED GALAXIES FROM HIGH-RESOLUTION NEAR-IR OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Calanog, J. A.; Cooray, A.; Ma, B.; Casey, C. M. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Wardlow, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Baes, M. [1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Bourne, N.; Dye, S. [School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom); Bussmann, R. S. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Eales, S. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); and others

2014-12-20

We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 μm bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey and Herschel Astrophysical Terahertz Large Area Survey. Out of 87 candidates with near-IR imaging, 15 (∼17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for submillimeter galaxies (SMGs). For four new sources that also have high-resolution submillimeter maps, we test for differential lensing between the stellar and dust components and find that the 880 μm magnification factor (μ{sub 880}) is ∼1.5 times higher than the near-IR magnification factor (μ{sub NIR}), on average. We also find that the stellar emission is ∼2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.

Temperature-dependent mid-IR absorption spectra of gaseous hydrocarbons

International Nuclear Information System (INIS)

Klingbeil, Adam E.; Jeffries, Jay B.; Hanson, Ronald K.

2007-01-01

Quantitative mid-IR absorption spectra (2500-3400 cm -1 ) for 12 pure hydrocarbon compounds are measured at temperatures ranging from 25 to 500 deg. C using an FTIR spectrometer. The hydrocarbons studied are n-pentane, n-heptane, n-dodecane, 2,2,4-trimethyl-pentane (iso-octane), 2-methyl-butane, 2-methyl-pentane, 2,4,4-trimethyl-1-pentene, 2-methyl-2-butene, propene, toluene, m-xylene, and ethylbenzene. Room-temperature measurements of neat hydrocarbon vapor were made with an instrument resolution of both 0.1 and 1 cm -1 (FWHM) to confirm that the high-resolution setting was required only to resolve the propene absorption spectrum while the spectra of the other hydrocarbons could be resolved with 1 cm -1 resolution. High-resolution (0.1 cm -1 ), room-temperature measurements of neat hydrocarbons were made at low pressure (∼1 Torr, 133 Pa) and compared to measurements of hydrocarbon/N 2 mixtures at atmospheric pressure to verify that no pressure broadening could be observed over this pressure range. The temperature was varied between 25 and 500 o C for atmospheric-pressure measurements of hydrocarbon/N 2 mixtures (X hydrocarbon ∼0.06-1.5%) and it was found that the absorption cross section shows simple temperature-dependent behavior for a fixed wavelength over this temperature range. Comparisons with previous FTIR data over a limited temperature range and with high-resolution laser absorption data over a wide temperature range show good agreement

THELI: CONVENIENT REDUCTION OF OPTICAL, NEAR-INFRARED, AND MID-INFRARED IMAGING DATA

International Nuclear Information System (INIS)

Schirmer, M.

2013-01-01

The last 15 years have seen a surge of new multi-chip optical and near-IR imagers. While some of them are accompanied by specific reduction pipelines, user-friendly and generic reduction tools are uncommon. In this paper I introduce THELI, an easy-to-use graphical interface driving an end-to-end pipeline for the reduction of any optical, near-IR, and mid-IR imaging data. The advantages of THELI when compared to other approaches are highlighted. Combining a multitude of processing algorithms and third party software, THELI provides researchers with a single, homogeneous tool. A short learning curve ensures quick success for new and more experienced observers alike. All tasks are largely automated, while at the same time a high level of flexibility and alternative reduction schemes ensure that widely different scientific requirements can be met. Over 90 optical and infrared instruments at observatories world-wide are pre-configured, while more can be added by the user. The Appendices contain three walk-through examples using public data (optical, near-IR, and mid-IR). Additional extensive documentation for training and troubleshooting is available online

Advances in Mid-IR Fiber Lasers: Tellurite, Fluoride and Chalcogenide

Directory of Open Access Journals (Sweden)

Mario Christian Falconi

2017-06-01

Full Text Available A review on the recent progress in modeling and fabrication of medium infrared (Mid-IR fiber lasers is reported. The main objective is to illustrate some recent examples of continuous wave optical sources at wavelengths longer than those commonly employed in telecom applications and allowing high beam quality. A small number of Mid-IR lasers, among the large variety of schemes, glasses, dopants and pumping schemes reported in literature, is selected on the basis of their slope efficiency and threshold pump power. In particular, tellurite, fluoride and chalcogenide fiber lasers are considered. More details are given with reference to the novel pumping schemes.

Image quality testing of assembled IR camera modules

Science.gov (United States)

Winters, Daniel; Erichsen, Patrik

2013-10-01

Infrared (IR) camera modules for the LWIR (8-12_m) that combine IR imaging optics with microbolometer focal plane array (FPA) sensors with readout electronics are becoming more and more a mass market product. At the same time, steady improvements in sensor resolution in the higher priced markets raise the requirement for imaging performance of objectives and the proper alignment between objective and FPA. This puts pressure on camera manufacturers and system integrators to assess the image quality of finished camera modules in a cost-efficient and automated way for quality control or during end-of-line testing. In this paper we present recent development work done in the field of image quality testing of IR camera modules. This technology provides a wealth of additional information in contrast to the more traditional test methods like minimum resolvable temperature difference (MRTD) which give only a subjective overall test result. Parameters that can be measured are image quality via the modulation transfer function (MTF) for broadband or with various bandpass filters on- and off-axis and optical parameters like e.g. effective focal length (EFL) and distortion. If the camera module allows for refocusing the optics, additional parameters like best focus plane, image plane tilt, auto-focus quality, chief ray angle etc. can be characterized. Additionally, the homogeneity and response of the sensor with the optics can be characterized in order to calculate the appropriate tables for non-uniformity correction (NUC). The technology can also be used to control active alignment methods during mechanical assembly of optics to high resolution sensors. Other important points that are discussed are the flexibility of the technology to test IR modules with different form factors, electrical interfaces and last but not least the suitability for fully automated measurements in mass production.

A Mid-IR Census of Dusty Supernovae From the Past Decade In Preparation for JWST

Science.gov (United States)

Fox, Ori; Andrews, Jennifer; Arendt, Rick; Clayton, Geoff; Dwek, Eli; Filippenko, Alex; Johansson, Joel; Kelly, Patrick; Krafton, Kelsie; Marston, Tony; Mauerhan, Jon; Szalai, Tamas; Van Dyk, Schuyler

2018-05-01

Over the past decade, our team has shown that a surprising number of different supernova (SN) subclasses have members that exhibit mid-infrared (mid-IR) emission from warm dust at late times (>100 days post-explosion). This work has used Spitzer 3.6 and 4.5 micron imaging to constrain the dust origin and heating mechanisms, but a number of questions still remain. How much dust can SNe IIP produce in their ejecta? What progenitor can produce such extreme mass-loss events required to form the large, dense, pre-existing dust shells observed in so many cases? Many of these SNe remain bright today, in some cases more than a decade after discovery. Continued mid-IR monitoring is necessary to answer these questions by measuring the full extent of either the newly formed dust mass or pre-existing dust shell. Furthermore, Spitzer observations of both old and new SNe will provide up to date flux estimates as we prepare for continued observations with JWST. This proposal will cap off nearly a decade of work and bridge the gap to the first few cycles of JWST.

MID-IR LUMINOSITIES AND UV/OPTICAL STAR FORMATION RATES AT z < 1.4

International Nuclear Information System (INIS)

Salim, Samir; Dickinson, Mark; Michael Rich, R.; Charlot, Stephane; Lee, Janice C.; Schiminovich, David; Perez-Gonzalez, Pablo G.; Ashby, Matthew L. N.; Noeske, Kai; Papovich, Casey; Weiner, Benjamin J.; Faber, S. M.; Ivison, Rob J.; Frayer, David T.; Walton, Josiah M.; Chary, Ranga-Ram; Bundy, Kevin; Koekemoer, Anton M.

2009-01-01

Ultraviolet (UV) nonionizing continuum and mid-infrared (IR) emission constitute the basis of two widely used star formation (SF) indicators at intermediate and high redshifts. We study 2430 galaxies with z 10 -10 12 L sun ). We show that the IR luminosity can be estimated from the UV and optical photometry to within a factor of 2, implying that most z IR >10 11 L sun , yet with little current SF. For them a reasonable amount of dust absorption of stellar light (but presumably higher than in nearby early-type galaxies) is sufficient to produce the observed levels of IR, which includes a large contribution from intermediate and old stellar populations. In our sample, which contains very few ultraluminous IR galaxies, optical and X-ray active galactic nuclei do not contribute on average more than ∼50% to the mid-IR luminosity, and we see no evidence for a large population of 'IR excess' galaxies.

Mid infrared resonant cavity detectors and lasers with epitaxial lead-chalcogenides

Science.gov (United States)

Zogg, H.; Rahim, M.; Khiar, A.; Fill, M.; Felder, F.; Quack, N.

2010-09-01

Wavelength tunable emitters and detectors in the mid-IR wavelength region allow applications including thermal imaging and gas spectroscopy. One way to realize such tunable devices is by using a resonant cavity. By mechanically changing the cavity length with MEMS mirror techniques, the wavelengths may be tuned over a considerable range. Resonant cavity enhanced detectors (RCED) are sensitive at the cavity resonance only. They may be applied for low resolution spectroscopy, and, when arrays of such detectors are realized, as multicolour IR-FPA or "IR-AFPA", adaptive focal plane arrays. We report the first room temperature mid-IR VECSEL (vertical external cavity surface emitting laser) with a wavelength above 3 μm. The active region is just 850 nm PbSe, followed by a 2.5 pair Bragg mirror. Output power is > 10 mW at RT.

GTC/CanariCam Mid-IR Imaging of the Fullerene-rich Planetary Nebula IC 418: Searching for the Spatial Distribution of Fullerene-like Molecules

Science.gov (United States)

Díaz-Luis, J. J.; García-Hernández, D. A.; Manchado, A.; García-Lario, P.; Villaver, E.; García-Segura, G.

2018-03-01

We present seeing-limited narrow-band mid-IR GTC/CanariCam images of the spatially extended fullerene-containing planetary nebula (PN) IC 418. The narrow-band images cover the C60 fullerene band at 17.4 μm, the polycyclic aromatic hydrocarbon like (PAH-like) feature at 11.3 μm, the broad 9–13 μm feature, and their adjacent continua at 9.8 and 20.5 μm. We study the relative spatial distribution of these complex species, all detected in the Spitzer and Infrared Space Observatory spectra of IC 418, with the aim of getting observational constraints to the formation process of fullerenes in H-rich circumstellar environments. A similar ring-like extended structure is seen in all narrow-band filters, except in the dust continuum emission at 9.8 μm, which peaks closer to the central star. The continuum-subtracted images display a clear ring-like extended structure for the carrier of the broad 9–13 μm emission, while the spatial distribution of the (PAH-like) 11.3 μm emission is not so well defined. Interestingly, a residual C60 17.4 μm emission (at about 4σ from the sky background) is seen when subtracting the dust continuum emission at 20.5 μm. This residual C60 emission, if real, might have several interpretations, the most exciting being perhaps that other fullerene-based species like hydrogenated fullerenes with very low H-content may contribute to the observed 17.4 μm emission. We conclude that higher sensitivity mid-IR images and spatially resolved spectroscopic observations (especially in the Q-band) are necessary to get some clues about fullerene formation in PNe.

Evaluation of MidIR fibre optic reflectance: Detection limit, reproducibility and binary mixture discrimination

Science.gov (United States)

Sessa, Clarimma; Bagán, Héctor; García, José Francisco

2013-11-01

MidIR fibre optic reflectance (MidIR-FORS) is a promising analytical technique in the field of science conservation, especially because it is non-destructive. Another advantage of MidIR-FORS is that the obtained information is representative, as a large amount of spectral data can be collected. Although the technique has a high potential and is almost routinely applied, its quality parameters have not been thoroughly studied in the specific application of analysis of artistic materials. The objective of this study is to evaluate the instrumental capabilities of MidIR-FORS for the analysis of artwork materials in terms of detection limit, reproducibility, and mixture characterisation. The study has been focused on oil easel painting and several paints of known composition have been analysed. Paint layers include blue pigments not only because of their important role along art history, but also because their physical and spectroscopic characteristics allow a better evaluation of the MidIR-FORS capabilities. The results of the analysis indicate that MidIR-FORS supplies a signal affected by different factors, such as the optical, morphological and physical properties of the surface, in addition to the composition of materials analysed. Consequently, the detection limits established are relatively high for artistic objects (Prussian blue - PB 2.1-6.5%; Phthalocyanine blue - Pht 6.3-10.2%; synthetic Ultramarine blue - UM 12.1%) and may therefore lead to an incomplete description of the artwork. Reproducibility of the technique over time and across surface has been determined. The results show that the major sources of dispersion are the heterogeneity of the pigments distribution, physical features, and band shape distortions. The total dispersion is around 4% for the most intense bands (oil) and increases up to 26% when weak or overlapped bands are considered (PB, Pht, UM). The application of different pre-treatments (cutoff of fibres absorption, Savizky-Golay smoothing

Ten-watt level picosecond parametric mid-IR source broadly tunable in wavelength

Science.gov (United States)

Vyvlečka, Michal; Novák, Ondřej; Roškot, Lukáscaron; Smrž, Martin; Mužík, Jiří; Endo, Akira; Mocek, Tomáš

2018-02-01

Mid-IR wavelength range (between 2 and 8 μm) offers perspective applications, such as minimally-invasive neurosurgery, gas sensing, or plastic and polymer processing. Maturity of high average power near-IR lasers is beneficial for powerful mid-IR generation by optical parametric conversion. We utilize in-house developed Yb:YAG thin-disk laser of 100 W average power at 77 kHz repetition rate, wavelength of 1030 nm, and about 2 ps pulse width for pumping of a ten-watt level picosecond mid-IR source. Seed beam is obtained by optical parametric generation in a double-pass 10 mm long PPLN crystal pumped by a part of the fundamental near-IR beam. Tunability of the signal wavelength between 1.46 μm and 1.95 μm was achieved with power of several tens of miliwatts. Main part of the fundamental beam pumps an optical parametric amplification stage, which includes a walk-off compensating pair of 10 mm long KTP crystals. We already demonstrated the OPA output signal and idler beam tunability between 1.70-1.95 μm and 2.18-2.62 μm, respectively. The signal and idler beams were amplified up to 8.5 W and 5 W, respectively, at 42 W pump without evidence of strong saturation. Thus, increase in signal and idler output power is expected for pump power increase.

Power scaling of ultrafast mid-IR source enabled by high-power fiber laser technology

Energy Technology Data Exchange (ETDEWEB)

Zhou, Gengji

2017-11-15

Ultrafast laser sources with high repetition-rate (>10 MHz) and tunable in the mid-infrared (IR) wavelength range of 7-18 μm hold promise for many important spectroscopy applications. Currently, these ultrafast mid- to longwavelength-IR sources can most easily be achieved via difference-frequency generation (DFG) between a pump beam and a signal beam. However, current ultrafast mid- to longwavelength-IR sources feature a low average power, which limits their applications. In this thesis, we propose and demonstrate a novel approach to power scaling of DFG-based ultrafast mid-IR laser sources. The essence of this novel approach is the generation of a high-energy signal beam. Both the pump beam and the signal beam are derived from a home-built Yb-fiber laser system that emits 165-fs pulses centered at 1035 nm with 30-MHz repetition rate and 14.5-W average power (corresponding to 483-nJ pulse energy). We employ fiber-optic self-phase modulation (SPM) to broaden the laser spectrum and generate isolated spectral lobes. Filtering the rightmost spectral lobe leads to femtosecond pulses with >10 nJ pulse energy. Tunable between 1.1-1.2 μm, this SPM-enabled ultrafast source exhibits ∝100 times higher pulse energy than can be obtained from Raman soliton sources in this wavelength range. We use this SPM-enabled source as the signal beam and part of the Yb-fiber laser output as the pump beam. By performing DFG in GaSe crystals, we demonstrate that power scaling of a DFG-based mid-IR source can be efficiently achieved by increasing the signal energy. The resulting mid-IR source is tunable from 7.4 μm to 16.8 μm. Up to 5.04-mW mid-IR pulses centered at 11 μm are achieved. The corresponding pulse energy is 167 pJ, representing nearly one order of magnitude improvement compared with other reported DFG-based mid-IR sources at this wavelength. Despite of low pulse energy, Raman soliton sources have become a popular choice as the signal source. We carry out a detailed study on

Power scaling of ultrafast mid-IR source enabled by high-power fiber laser technology

International Nuclear Information System (INIS)

Zhou, Gengji

2017-11-01

Ultrafast laser sources with high repetition-rate (>10 MHz) and tunable in the mid-infrared (IR) wavelength range of 7-18 μm hold promise for many important spectroscopy applications. Currently, these ultrafast mid- to longwavelength-IR sources can most easily be achieved via difference-frequency generation (DFG) between a pump beam and a signal beam. However, current ultrafast mid- to longwavelength-IR sources feature a low average power, which limits their applications. In this thesis, we propose and demonstrate a novel approach to power scaling of DFG-based ultrafast mid-IR laser sources. The essence of this novel approach is the generation of a high-energy signal beam. Both the pump beam and the signal beam are derived from a home-built Yb-fiber laser system that emits 165-fs pulses centered at 1035 nm with 30-MHz repetition rate and 14.5-W average power (corresponding to 483-nJ pulse energy). We employ fiber-optic self-phase modulation (SPM) to broaden the laser spectrum and generate isolated spectral lobes. Filtering the rightmost spectral lobe leads to femtosecond pulses with >10 nJ pulse energy. Tunable between 1.1-1.2 μm, this SPM-enabled ultrafast source exhibits ∝100 times higher pulse energy than can be obtained from Raman soliton sources in this wavelength range. We use this SPM-enabled source as the signal beam and part of the Yb-fiber laser output as the pump beam. By performing DFG in GaSe crystals, we demonstrate that power scaling of a DFG-based mid-IR source can be efficiently achieved by increasing the signal energy. The resulting mid-IR source is tunable from 7.4 μm to 16.8 μm. Up to 5.04-mW mid-IR pulses centered at 11 μm are achieved. The corresponding pulse energy is 167 pJ, representing nearly one order of magnitude improvement compared with other reported DFG-based mid-IR sources at this wavelength. Despite of low pulse energy, Raman soliton sources have become a popular choice as the signal source. We carry out a detailed study on

Keck i LWS Mid-Ir Images and Photometry of 9P/TEMPEL 1

Science.gov (United States)

Fernandez, Y. R.; Lisse, C. M.; A'Hearn, M. F.; Belton, M. J. S.

2010-01-01

This data set contains raw and reduced mid-infrared images and photometry of comet 9P/Tempel 1, the target of the Deep Impact mission. Images were acquired on the night of 21 August 2000, about 7.5 months after perihelion, by Y. Fernandez, C. Lisse, M. A'Hearn and M. Belton using the Long Wavelength Spectrometer instrument at the Keck I telescope.

Mid-IR Imaging of Orion BN/KL: Modeling of Physical Conditions and Energy Balance

Science.gov (United States)

Gezari, Daniel; Varosi, Frank; Dwek, Eli; Danchi, William C.; Tan, Jonathan; Okumura, Shin-ichiro

2016-01-01

We have modeled two mid-infrared imaging photometry data sets to determine the spatial distribution of physical conditions in the BN/KL (Becklin-Neugebauer / Kleinmann-Low) infrared complex. We observed the BN/KL region using the 10-meter Keck I telescope and the LWS (Living With a Star) in the direct imaging mode, over a 13 inch by 19 inch field . We also modeled images obtained with COMICS (Cooled Mid-Infrared Camera and Spectrometer, Kataza et al. 2000) at the 8.2-meter SUBARU telescope, over a total field of view [which] is 31 inches by 41 inches in a total of nine bands: 7.8, 8.8, 9.7, 10.5, 11.7, 12.4, 18.5, 20.8 and 24.8 microns with 1-micron bandwidth interference filters.

Mid-IR DIAL for high-resolution mapping of explosive precursors

Science.gov (United States)

Mitev, V.; Babichenko, S.; Bennes, J.; Borelli, R.; Dolfi-Bouteyre, A.; Fiorani, L.; Hespel, L.; Huet, T.; Palucci, A.; Pistilli, M.; Puiu, A.; Rebane, O.; Sobolev, I.

2013-10-01

A DIAL instrument on a moving platform is seen as a valuable remote sensing component in a sensor network for area monitoring, targeting sites involved in unauthorised explosive manufacturing. Such instrument will perform the area mapping of the vapour concentration of key substances, known to be used as precursors in explosive fabrication, such as acetone and nitromethane. The IR spectra of acetone and nitromethane vapours have been defined from available spectroscopy databases and from laboratory measurements as showing optimal spectral band for the DIAL operation in the spectral range of 3.0 μm - 3.5 μm. The DIAL operation has been numerically simulated, with inputs based on the HITRAN database, the U.S. Standard Atmosphere and aerosol simulation software package OPAC. A combination of OPO and OPA has been chosen as a transmitter, where the idler wavelength is used for probing, with wavelength tuning in sequence. A scanner mounted on top of the coaxially aligned laser and receiver, is capable of covering almost 360 degrees horizontally and +/-30 degrees vertically. The detection is performed by a photovoltaic photodiode with 4-stage cooling, with a signal digitalisation having 14 bit amplitude resolution and 125 Ms/s sampling rate. Here we present the development and the first test of the DIAL instrument.

High-definition Fourier Transform Infrared (FT-IR) Spectroscopic Imaging of Human Tissue Sections towards Improving Pathology

Science.gov (United States)

Nguyen, Peter L.; Davidson, Bennett; Akkina, Sanjeev; Guzman, Grace; Setty, Suman; Kajdacsy-Balla, Andre; Walsh, Michael J.

2015-01-01

High-definition Fourier Transform Infrared (FT-IR) spectroscopic imaging is an emerging approach to obtain detailed images that have associated biochemical information. FT-IR imaging of tissue is based on the principle that different regions of the mid-infrared are absorbed by different chemical bonds (e.g., C=O, C-H, N-H) within cells or tissue that can then be related to the presence and composition of biomolecules (e.g., lipids, DNA, glycogen, protein, collagen). In an FT-IR image, every pixel within the image comprises an entire Infrared (IR) spectrum that can give information on the biochemical status of the cells that can then be exploited for cell-type or disease-type classification. In this paper, we show: how to obtain IR images from human tissues using an FT-IR system, how to modify existing instrumentation to allow for high-definition imaging capabilities, and how to visualize FT-IR images. We then present some applications of FT-IR for pathology using the liver and kidney as examples. FT-IR imaging holds exciting applications in providing a novel route to obtain biochemical information from cells and tissue in an entirely label-free non-perturbing route towards giving new insight into biomolecular changes as part of disease processes. Additionally, this biochemical information can potentially allow for objective and automated analysis of certain aspects of disease diagnosis. PMID:25650759

A Q-switched Ho:YAG laser assisted nanosecond time-resolved T-jump transient mid-IR absorbance spectroscopy with high sensitivity

Energy Technology Data Exchange (ETDEWEB)

Li, Deyong; Li, Yunliang; Li, Hao; Weng, Yuxiang, E-mail: yxweng@iphy.ac.cn [Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Xianyou [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, Qingxu [School of Physics and Optoelectronic Technology, Dalian University of Technology, No. 2, Linggong Road, Dalian 116023 (China)

2015-05-15

Knowledge of dynamical structure of protein is an important clue to understand its biological function in vivo. Temperature-jump (T-jump) time-resolved transient mid-IR absorbance spectroscopy is a powerful tool in elucidating the protein dynamical structures and the folding/unfolding kinetics of proteins in solution. A home-built setup of T-jump time-resolved transient mid-IR absorbance spectroscopy with high sensitivity is developed, which is composed of a Q-switched Cr, Tm, Ho:YAG laser with an output wavelength at 2.09 μm as the T-jump heating source, and a continuous working CO laser tunable from 1580 to 1980 cm{sup −1} as the IR probe. The results demonstrate that this system has a sensitivity of 1 × 10{sup −4} ΔOD for a single wavelength detection, and 2 × 10{sup −4} ΔOD for spectral detection in amide I′ region, as well as a temporal resolution of 20 ns. Moreover, the data quality coming from the CO laser is comparable to the one using the commercial quantum cascade laser.

Ge-rich graded-index Si1-xGex devices for MID-IR integrated photonics

Science.gov (United States)

Ramirez, J. M.; Vakarin, V.; Liu, Q.; Frigerio, J.; Ballabio, A.; Le Roux, X.; Benedikovic, D.; Alonso-Ramos, C.; Isella, G.; Vivien, L.; Marris-Morini, D.

2018-02-01

Mid-infrared (mid-IR) silicon photonics is becoming a prominent research with remarkable potential in several applications such as in early medical diagnosis, safe communications, imaging, food safety and many more. In the quest for the best material platform to develop new photonic systems, Si and Ge depart with a notable advantage over other materials due to the high processing maturity accomplished during the last part of the 20th century through the deployment of the CMOS technology. From an optical viewpoint, combining Si with Ge to obtain SiGe alloys with controlled stoichiometry is also of interest for the photonic community since permits to increase the effective refractive index and the nonlinear parameter, providing a fascinating playground to exploit nonlinear effects. Furthermore, using Ge-rich SiGe gives access to a range of deep mid-IR wavelengths otherwise inaccessible (λ 2-20 μm). In this paper, we explore for the first time the limits of this approach by measuring the spectral loss characteristic over a broadband wavelength range spanning from λ = 5.5 μm to 8.5 μm. Three different SiGe waveguide platforms are compared, each one showing higher compactness than the preceding through the engineering of the vertical Ge profile, giving rise to different confinement characteristics to the propagating modes. A flat propagation loss characteristic of 2-3 dB/cm over the entire wavelength span is demonstrated in Ge-rich graded-index SiGe waveguides of only 6 μm thick. Also, the role of the overlap fraction of the confined optical mode with the Si-rich area at the bottom side of the epitaxial SiGe waveguide is put in perspective, revealing a lossy characteristic compared to the other designs were the optical mode is located in the Ge-rich area at the top of the waveguide uniquely. These Ge-rich graded-index SiGe waveguides may pave the way towards a new generation of photonic integrated circuits operating at deep mid-IR wavelengths.

The mid-IR silicon photonics sensor platform (Conference Presentation)

Science.gov (United States)

Kimerling, Lionel; Hu, Juejun; Agarwal, Anuradha M.

2017-02-01

Advances in integrated silicon photonics are enabling highly connected sensor networks that offer sensitivity, selectivity and pattern recognition. Cost, performance and the evolution path of the so-called `Internet of Things' will gate the proliferation of these networks. The wavelength spectral range of 3-8um, commonly known as the mid-IR, is critical to specificity for sensors that identify materials by detection of local vibrational modes, reflectivity and thermal emission. For ubiquitous sensing applications in this regime, the sensors must move from premium to commodity level manufacturing volumes and cost. Scaling performance/cost is critically dependent on establishing a minimum set of platform attributes for point, wearable, and physical sensing. Optical sensors are ideal for non-invasive applications. Optical sensor device physics involves evanescent or intra-cavity structures for applied to concentration, interrogation and photo-catalysis functions. The ultimate utility of a platform is dependent on sample delivery/presentation modalities; system reset, recalibration and maintenance capabilities; and sensitivity and selectivity performance. The attributes and performance of a unified Glass-on-Silicon platform has shown good prospects for heterogeneous integration on materials and devices using a low cost process flow. Integrated, single mode, silicon photonic platforms offer significant performance and cost advantages, but they require discovery and qualification of new materials and process integration schemes for the mid-IR. Waveguide integrated light sources based on rare earth dopants and Ge-pumped frequency combs have promise. Optical resonators and waveguide spirals can enhance sensitivity. PbTe materials are among the best choices for a standard, waveguide integrated photodetector. Chalcogenide glasses are capable of transmitting mid-IR signals with high transparency. Integrated sensor case studies of i) high sensitivity analyte detection in

Mid-IR spectra of different conformers of phenylalanine in the gas phase

NARCIS (Netherlands)

von Helden, G.; Compagnon, I.; Blom, M. N.; Frankowski, M.; Erlekam, U.; Oomens, J.; Brauer, B.; Gerber, R. B.; Meijer, G.

2008-01-01

The experimental mid- and far-IR spectra of six conformers of phenylalanine in the gas phase are presented. The experimental spectra are compared to spectra calculated at the B3LYP and at the MP2 level. The differences between B3LYP and MP2 IR spectra are found to be small. The agreement between

Mid-IR Imaging: Upconversion imager improves IR gas sensing

DEFF Research Database (Denmark)

Sahlberg, Anna-Lena; Li, Zhongshan; Høgstedt, Lasse

2014-01-01

A nonlinear upconversion detector shows near-shot-noise-limited performance and compares favorably—while adding additional imaging information—to conventional cryogenic detectors in the measurement of trace-level gases at atmospheric pressure....

Mid infrared LHS system packaging using flexible waveguides

Science.gov (United States)

Yu, Chung

1987-01-01

As mid IR fiber optic systems are rapidly approaching a reality, so is the feasibility of fiber optic laser heterodyne systems. Laser heterodyne spectroscopy for high resolution monitoring of atmospheric gaseous pollutants is necessarily in the mid IR, the region in which the absorption signature of gaseous species is most prominent. It so happens that the lowest theoretical loss due to Rayleigh-Brillouin scattering also lies in the mid IR. Prospects of highly efficient laser heterodyne systems are thus very good. Such fibers are now beginning to be commercially available, and a test program is being conducted for such fibers with ambient temperature ranging from cryogenic to above room, and stringest mechanical flexibility requirements. Preliminary results are encouraging. A program is being started to explore the possibility of mid IR fiber optic device applications, by taking advantage of this phonon rich region. The potential long interaction length in fibers coupled with predicted extremely low losses point to stimulated Brillouin scattering based devices in the mW range. The generation of backscattered sBs at low laser powers is significant not only as an ultimate power limiting factor for laser transmission in fibers in the mid IR, but also the presence of frequency-shifted multiple order sBs Stokes and antiStokes lines will certainly have severe effect on the laser beats crucial in high resolution heterodyne spectroscopy.

Optimization of silicon waveguides for gas detection application at mid-IR wavelengths

Science.gov (United States)

Butt, M. A.; Kozlova, E. S.

2018-04-01

There are several trace gases such as N2O, CO, CO2, NO, H2O, NO2, NH3, CH4 etc. which have their absorption peaks in Mid-IR spectrum These gases strongly absorb in the mid-IR > 2.5 μm spectral region due to their fundamental rotational and vibrational transitions. In this work, we modelled and optimized three different kinds of waveguides such as rib, strip and slot based on silicon platform to obtain maximum evanescent field ratio. These waveguides are designed at 3.39 μm and 4.67 μm which correspond to the absorption line of methane (CH4) and carbon monoxide (CO) respectively.

Multiple-octave spanning high-energy mid-IR supercontinuum generation in bulk quadratic nonlinear crystals

DEFF Research Database (Denmark)

Zhou, Binbin; Bache, Morten

2016-01-01

Bright and broadband coherent mid-IR radiation is important for exciting and probing molecular vibrations. Using cascaded nonlinearities in conventional quadratic nonlinear crystals like lithium niobate, self-defocusing near-IR solitons have been demonstrated that led to very broadband...

Quantitative gas analysis with FT-IR

DEFF Research Database (Denmark)

Bak, J.; Larsen, A.

1995-01-01

Calibration spectra of CO in the 2.38-5100 ppm concentration range (22 spectra) have been measured with a spectral resolution of 4 cm(-1), in the mid-IR (2186-2001 cm(-1)) region, with a Fourier transform infrared (FT-IR) instrument. The multivariate calibration method partial least-squares (PLS1...

Optical design for a breadboard high-resolution spectrometer for SIRTF/IRS

Science.gov (United States)

Brown, Robert J.; Houck, James R.; van Cleve, Jeffrey E.

1996-11-01

The optical design of a breadboard high resolution infrared spectrometer for the IRS instrument on the SIRTF mission is discussed. The spectrometer uses a crossed echelle grating configuration to cover the spectral region from 10 to 20 micrometer with a resolving power of approximately equals 600. The all reflective spectrometer forms a nearly diffraction limited image of the two dimensional spectrum on a 128 multiplied by 128 arsenic doped silicon area array with 75 micrometer pixels. The design aspects discussed include, grating numerology, image quality, packaging and alignment philosophy.

Shaping and detecting mid-IR light with a spatial light modulator

CSIR Research Space (South Africa)

Maweza, Elijah L

2016-10-01

Full Text Available modulator Maweza, Elijah L Gailele, Lucas M Strauss, Hencharl J Litvin, Ihar Forbes, Andrew Dudley, Angela L ABSTRACT: We demonstrate the operation and calibration of a spatial light modulator in the mid-IR region by creating and measuring...

Laser wakefield acceleration with high-power, few-cycle mid-IR lasers

OpenAIRE

Papp, Daniel; Wood, Jonathan C.; Gruson, Vincent; Bionta, Mina; Gruse, Jan-Niclas; Cormier, Eric; Najmudin, Zulfikar; Légaré, François; Kamperidis, Christos

2018-01-01

The study of laser wakefield electron acceleration (LWFA) using mid-IR laser drivers is a promising path for future laser driven electronaccelerators, when compared to traditional near-IR laser drivers uperating at 0.8-1 {\\mu}m central wavelength ({\\lambda}laser), as the necessary vector potential a_0 for electron injection can be achieved with smaller laser powers due to the linear dependence on {\\lambda}laser. In this work, we perform 2D PIC simulations on LWFA using few-cycle high power (5...

Energetic mid-IR femtosecond pulse generation by self-defocusing soliton-induced dispersive waves in a bulk quadratic nonlinear crystal

DEFF Research Database (Denmark)

Zhou, Binbin; Guo, Hairun; Bache, Morten

2015-01-01

Generating energetic femtosecond mid-IR pulses is crucial for ultrafast spectroscopy, and currently relies on parametric processes that, while efficient, are also complex. Here we experimentally show a simple alternative that uses a single pump wavelength without any pump synchronization and with...... by using large-aperture crystals. The technique can readily be implemented with other crystals and laser wavelengths, and can therefore potentially replace current ultrafast frequency-conversion processes to the mid-IR....... and without critical phase-matching requirements. Pumping a bulk quadratic nonlinear crystal (unpoled LiNbO3 cut for noncritical phase-mismatched interaction) with sub-mJ near-IR 50-fs pulses, tunable and broadband (∼ 1,000 cm−1) mid-IR pulses around 3.0 μm are generated with excellent spatio-temporal pulse...... quality, having up to 10.5 μJ energy (6.3% conversion). The mid-IR pulses are dispersive waves phase-matched to near-IR self-defocusing solitons created by the induced self-defocusing cascaded nonlinearity. This process is filament-free and the input pulse energy can therefore be scaled arbitrarily...

Ultra-broadband mid-wave-IR upconversion detection

DEFF Research Database (Denmark)

Barh, Ajanta; Pedersen, Christian; Tidemand-Lichtenberg, Peter

2017-01-01

In this Letter, we demonstrate efficient room temperature detection of ultra-broadband mid-wave-infrared (MWIR) light with an almost flat response over more than 1200 nm, exploiting an efficient nonlinear upconversion technique. Black-body radiation from a hot soldering iron rod is used as the IR...... test source. Placing a 20 mm long periodically poled lithium niobate crystal in a compact intra-cavity setup (> 20 WCW pump at 1064 nm), MWIR wavelengths ranging from 3.6 to 4.85 mu m are upconverted to near-infrared (NIR) wavelengths (820-870 nm). The NIR light is detected using a standard low...

Few-cycle nonlinear mid-IR pulse generated with cascaded quadratic nonlinearities

DEFF Research Database (Denmark)

Bache, Morten; Liu, Xing; Zhou, Binbin

Generating few-cycle energetic and broadband mid-IR pulses is an urgent current challenge in nonlinear optics. Cascaded second-harmonic generation (SHG) gives access to an ultrafast and octave-spanning self-defocusing nonlinearity: when ΔkL >> 2π the pump experiences a Kerr-like nonlinear index...

PEPSI, the High-Resolution Optical-IR Spectrograph for the LBT

Science.gov (United States)

Andersen, Michael; Strassmeier, Klaus; Hoffman, Axel; Woche, Manfred; Spano, Paolo

PEPSI is a high resolution fibre feed optical-IR polarimetric echelle spectrograph for the Large Binocular Telescope (LBT). PEPSI utilizes the two 8.4m LBT apertures to simultaneously record four polarization states at a resolution of 120.000. The extension of the coverage towards the IR is mainly motivated by the larger Zeeman splitting of IR lines, which would allow to study weaker/fainter magnetic structures on stars. The two optical arms, which also have an integral light mode with R up to 300.000, are under construction, while the IR arm is being designed.

What can we expect from near to mid-term direct imaging programs?

Science.gov (United States)

Boccaletti, A.

2015-10-01

Direct imaging for exoplanets has made enormous progress in the last decades owing to the advent of new technologies, efficient algorithms for postprocessing and dedicated observing strategies. A few young giant exoplanets were detected with the previous generation of instruments (beta Pic b, HS3799bcde, HR95086b ...). While SPHERE and GPI were conceived with this very purpose, we are thus expecting many more discoveries in the next years. SPHERE comes with a series of facilities to characterize the atmosphere of these planets, from the visible to the near IR, with broad band, narrow band filters, and low to medium resolution spectroscopy as well. It is also a fabulous instrument to study circumstellar disks both intensity and polarimetry in order to establish the link between planets and their environments. A large survey of 600 targets on a 5 years baseline has been started. The next space telescope, JWST equipped with MIRI and NIRCAM will extend the ability to characterize young giants in the mid IR. NO doubt we will learn more about their atmospheres. Finally, by the next decade, very large apertures will become available on the ground. Extremely Large Telescope will have general first light instruments (MICADO, HARMONI), but some programs to image and characterize young giant planets around very distant stars (>100pc) will be feasible. For much ambitious goal, detecting telluric planets and studying their atmosphere, two paths are now considered either from space (WFIRST AFTA-C is good candidate) and from the Ground with SPHERE-like instruments on ELTs. A review of achievments and perspectives in the context of direct imaging will be presented.

Low loss mid-IR transmission bands using silica hollow-core anisotropic anti-resonant fibers

DEFF Research Database (Denmark)

Habib, Selim; Bang, Ole; Bache, Morten

2016-01-01

In this paper, a node-free anisotropic hollow-core anti-resonant fiber has been proposed to give low transmission loss in the near-IR to mid-IR spectral regime. The proposed silica-based fiber design shows transmission loss below 10 dB/km at 2.94 μm with multiple low loss transmission bands. Tran...

Near-IR High-Resolution Imaging Polarimetry of the SU Aur Disk: Clues for Tidal Tails?

Science.gov (United States)

De Leon, Jerome; Michihiro, Takami; Karr, Jennifer; Hashimoto, Jun; Kudo, Tomoyuki; Sitko, Michael; Mayama, Satoshi; Kusakabe, Nobuyuki; Grady, Carol A.; McElwain, Michael W.

2015-01-01

We present new high-resolution (approximately 0.09) H-band imaging observations of the circumstellar disk around the T Tauri star SU Aur. Our observations with Subaru-HiCIAO have revealed the presence of scattered light as close as 0.15 (approximately 20 AU) to the star. Within our image, we identify bright emission associated with a disk with a minimum radius of approximately 90 AU, an inclination of approximately 35 deg from the plane of the sky, and an approximate PA of 15 deg for the major axis. We find a brightness asymmetry between the northern and southern sides of the disk due to a non-axisymmetric disk structure. We also identify a pair of asymmetric tail structures extending east and west from the disk. The western tail extends at least 2. 5 (350 AU) from the star, and is probably associated with a reflection nebula previously observed at optical and near-IR wavelengths. The eastern tail extends at least 1 (140 AU) at the present signal-to-noise. These tails are likely due to an encounter with an unseen brown dwarf, but our results do not exclude the explanation that these tails are outflow cavities or jets.

Thermal-to-visible transducer (TVT) for thermal-IR imaging

Science.gov (United States)

Flusberg, Allen; Swartz, Stephen; Huff, Michael; Gross, Steven

2008-04-01

We have been developing a novel thermal-to-visible transducer (TVT), an uncooled thermal-IR imager that is based on a Fabry-Perot Interferometer (FPI). The FPI-based IR imager can convert a thermal-IR image to a video electronic image. IR radiation that is emitted by an object in the scene is imaged onto an IR-absorbing material that is located within an FPI. Temperature variations generated by the spatial variations in the IR image intensity cause variations in optical thickness, modulating the reflectivity seen by a probe laser beam. The reflected probe is imaged onto a visible array, producing a visible image of the IR scene. This technology can provide low-cost IR cameras with excellent sensitivity, low power consumption, and the potential for self-registered fusion of thermal-IR and visible images. We will describe characteristics of requisite pixelated arrays that we have fabricated.

High-Energy, Multi-Octave-Spanning Mid-IR Sources via Adiabatic Difference Frequency Generation

Science.gov (United States)

2016-10-17

MASSACHUSETTS AVE CAMBRIDGE , MA 02139-4301 US 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) AF Office...ADFG) stage, illustrated in Fig. 2. This system represents a very simple extension of a near-IR OPCPA system to octave-spanning mid-IR, requiring...retrieved, as shown in Fig. 10. For illustration , 3 pulse shapes were selected. First, a simple linear chirp was applied to show that the pulse can be

Spitzer mid-IR spectroscopy of powerful 2Jy and 3CRR radio galaxies. II. AGN power indicators and unification

Energy Technology Data Exchange (ETDEWEB)

Dicken, D. [CEA-Saclay, F-91191 Gif-sur-Yvette (France); Tadhunter, C. [University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Morganti, R. [ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Axon, D.; Robinson, A.; Magagnoli, M. [Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States); Kharb, P. [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560034 (India); Ramos Almeida, C. [Instituto de Astrofisica de Canarias (IAC), C/V ia Lactea, s/n, E-38205 La Laguna, Tenerife (Spain); Mingo, B. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Hardcastle, M. [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Nesvadba, N. P. H.; Singh, V. [Institut d' Astrophysique Spatiale, CNRS, Université Paris Sud, F-91405 Orsay (France); Kouwenhoven, M. B. N. [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Haidian Qu, Beijing 100871 (China); Rose, M.; Spoon, H. [224 Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Inskip, K. J. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Holt, J., E-mail: daniel.dicken@cea.fr [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

2014-06-20

It remains uncertain which continuum and emission line diagnostics best indicate the bolometric powers of active galactic nuclei (AGNs), especially given the attenuation caused by the circumnuclear material and the possible contamination by components related to star formation. Here we use mid-IR spectra along with multiwavelength data to investigate the merit of various diagnostics of AGN radiative power, including the mid-IR [Ne III] λ25.89 μm and [O IV] λ25.89 μm fine-structure lines, the optical [O III] λ5007 forbidden line, and mid-IR 24 μm, 5 GHz radio, and X-ray continuum emission, for complete samples of 46 2Jy radio galaxies (0.05 < z < 0.7) and 17 3CRR FRII radio galaxies (z < 0.1). We find that the mid-IR [O IV] line is the most reliable indicator of AGN power for powerful radio-loud AGNs. By assuming that the [O IV] is emitted isotropically, and comparing the [O III] and 24 μm luminosities of the broad- and narrow-line AGNs in our samples at fixed [O IV] luminosity, we show that the [O III] and 24 μm emission are both mildly attenuated in the narrow-line compared to the broad-line objects by a factor of ≈2. However, despite this attenuation, the [O III] and 24 μm luminosities are better AGN power indicators for our sample than either the 5 GHz radio or the X-ray continuum luminosities. We also detect the mid-IR 9.7 μm silicate feature in the spectra of many objects but not ubiquitously: at least 40% of the sample shows no clear evidence for these features. We conclude that, for the majority of powerful radio galaxies, the mid-IR lines are powered by AGN photoionization.

Application-specific specialty microstructured optical fibers for mid-IR and THz photonics (Invited)

DEFF Research Database (Denmark)

Pal, Bishnu P.; Barh, Ajanta; Varshney, Ravi K.

2016-01-01

A review of several of our designed specialty microstructured optical fibers (MOFs) for mid-IR and THz generation and transmission including high power transmission is presented. Extensive results on performance of the designed MOFs are described....

Mid-space-independent deformable image registration.

Science.gov (United States)

Aganj, Iman; Iglesias, Juan Eugenio; Reuter, Martin; Sabuncu, Mert Rory; Fischl, Bruce

2017-05-15

Aligning images in a mid-space is a common approach to ensuring that deformable image registration is symmetric - that it does not depend on the arbitrary ordering of the input images. The results are, however, generally dependent on the mathematical definition of the mid-space. In particular, the set of possible solutions is typically restricted by the constraints that are enforced on the transformations to prevent the mid-space from drifting too far from the native image spaces. The use of an implicit atlas has been proposed as an approach to mid-space image registration. In this work, we show that when the atlas is aligned to each image in the native image space, the data term of implicit-atlas-based deformable registration is inherently independent of the mid-space. In addition, we show that the regularization term can be reformulated independently of the mid-space as well. We derive a new symmetric cost function that only depends on the transformation morphing the images to each other, rather than to the atlas. This eliminates the need for anti-drift constraints, thereby expanding the space of allowable deformations. We provide an implementation scheme for the proposed framework, and validate it through diffeomorphic registration experiments on brain magnetic resonance images. Copyright © 2017 Elsevier Inc. All rights reserved.

Image registration of naval IR images

Science.gov (United States)

Rodland, Arne J.

1996-06-01

In a real world application an image from a stabilized sensor on a moving platform will not be 100 percent stabilized. There will always be a small unknown error in the stabilization due to factors such as dynamic deformations in the structure between sensor and reference Inertial Navigation Unit, servo inaccuracies, etc. For a high resolution imaging sensor this stabilization error causes the image to move several pixels in unknown direction between frames. TO be able to detect and track small moving objects from such a sensor, this unknown movement of the sensor image must be estimated. An algorithm that searches for land contours in the image has been evaluated. The algorithm searches for high contrast points distributed over the whole image. As long as moving objects in the scene only cover a small area of the scene, most of the points are located on solid ground. By matching the list of points from frame to frame, the movement of the image due to stabilization errors can be estimated and compensated. The point list is searched for points with diverging movement from the estimated stabilization error. These points are then assumed to be located on moving objects. Points assumed to be located on moving objects are gradually exchanged with new points located in the same area. Most of the processing is performed on the list of points and not on the complete image. The algorithm is therefore very fast and well suited for real time implementation. The algorithm has been tested on images from an experimental IR scanner. Stabilization errors were added artificially to the image such that the output from the algorithm could be compared with the artificially added stabilization errors.

Soliton-plasma nonlinear dynamics in mid-IR gas-filled hollow-core fibers

DEFF Research Database (Denmark)

Habib, Selim; Markos, Christos; Bang, Ole

2017-01-01

We investigate numerically soliton-plasma interaction in a noble-gas-filled silica hollow-core anti-resonant fiber pumped in the mid-IR at 3.0 mu m. We observe multiple soliton self-compression stages due to distinct stages where either the self-focusing or the self-defocusing nonlinearity...

Improved mid infrared detector for high spectral or spatial resolution and synchrotron radiation use

Energy Technology Data Exchange (ETDEWEB)

Faye, Mbaye; Bordessoule, Michel; Kanouté, Brahim; Brubach, Jean-Blaise; Roy, Pascale [Synchrotron SOLEIL, L’Orme des Merisiers, F-91192 Gif-sur-Yvette (France); Manceron, Laurent [Synchrotron SOLEIL, L’Orme des Merisiers, F-91192 Gif-sur-Yvette (France); Laboratoire MONARIS, CNRS-Université Pierre et Marie Curie, UMR 8233, 4 Place Jussieu, F-75252 Paris Cedex (France)

2016-06-15

When using bright, small effective size sources, such as synchrotron radiation light beam, for broadband spectroscopy at spectral or spatial high resolution for mid-IR FTIR measurements, a marked detectivity improvement can be achieved by setting up a device matching the detector optical étendue to that of the source. Further improvement can be achieved by reducing the background unmodulated flux and other intrinsic noise sources using a lower temperature cryogen, such as liquid helium. By the combined use of cooled apertures, cold reimaging optics, filters and adapted detector polarization, and preamplification electronics, the sensitivity of a HgCdTe photoconductive IR detector can be improved by a significant factor with respect to standard commercial devices (more than one order of magnitude on average over 6–20 μm region) and the usable spectral range extended to longer wavelengths. The performances of such an optimized detector developed on the AILES Beamline at SOLEIL are presented here.

Optical design of a versatile FIRST high-resolution near-IR spectrograph

Science.gov (United States)

Zhao, Bo; Ge, Jian

2012-09-01

We report the update optical design of a versatile FIRST high resolution near IR spectrograph, which is called Florida IR Silicon immersion grating spectromeTer (FIRST). This spectrograph uses cross-dispersed echelle design with white pupils and also takes advantage of the image slicing to increase the spectra resolution, while maintaining the instrument throughput. It is an extremely high dispersion R1.4 (blazed angle of 54.74°) silicon immersion grating with a 49 mm diameter pupil is used as the main disperser at 1.4μm -1.8μm to produce R=72,000 while an R4 echelle with the same pupil diameter produces R=60,000 at 0.8μm -1.35μm. Two cryogenic Volume Phase Holographic (VPH) gratings are used as cross-dispersers to allow simultaneous wavelength coverage of 0.8μm -1.8μm. The butterfly mirrors and dichroic beamsplitters make a compact folding system to record these two wavelength bands with a 2kx2k H2RG array in a single exposure. By inserting a mirror before the grating disperser (the SIG and the echelle), this spectrograph becomes a very efficient integral field 3-D imaging spectrograph with R=2,000-4,000 at 0.8μm-1.8μm by coupling a 10x10 telescope fiber bundle with the spectrograph. Details about the optical design and performance are reported.

Direct phase-locking of a 8.6-μm quantum cascade laser to a mid-IR optical frequency comb: application to precision spectroscopy of N2O.

Science.gov (United States)

Gambetta, Alessio; Cassinerio, Marco; Coluccelli, Nicola; Fasci, Eugenio; Castrillo, Antonio; Gianfrani, Livio; Gatti, Davide; Marangoni, Marco; Laporta, Paolo; Galzerano, Gianluca

2015-02-01

We developed a high-precision spectroscopic system at 8.6 μm based on direct heterodyne detection and phase-locking of a room-temperature quantum-cascade-laser against an harmonic, 250-MHz mid-IR frequency comb obtained by difference-frequency generation. The ∼30  dB signal-to-noise ratio of the detected beat-note together with the achieved closed-loop locking bandwidth of ∼500  kHz allows for a residual integrated phase noise of 0.78 rad (1 Hz-5 MHz), for an ultimate resolution of ∼21  kHz, limited by the measured linewidth of the mid-IR comb. The system was used to perform absolute measurement of line-center frequencies for the rotational components of the ν2 vibrational band of N2O, with a relative precision of 3×10(-10).

Near-IR imaging of cracks in teeth

Science.gov (United States)

Fried, William A.; Simon, Jacob C.; Lucas, Seth; Chan, Kenneth H.; Darling, Cynthia L.; Staninec, Michal; Fried, Daniel

2014-02-01

Dental enamel is highly transparent at near-IR wavelengths and several studies have shown that these wavelengths are well suited for optical transillumination for the detection and imaging of tooth decay. We hypothesize that these wavelengths are also well suited for imaging cracks in teeth. Extracted teeth with suspected cracks were imaged at several wavelengths in the near-IR from 1300-1700-nm. Extracted teeth were also examined with optical coherence tomography to confirm the existence of suspected cracks. Several teeth of volunteers were also imaged in vivo at 1300-nm to demonstrate clinical potential. In addition we induced cracks in teeth using a carbon dioxide laser and imaged crack formation and propagation in real time using near-IR transillumination. Cracks were clearly visible using near-IR imaging at 1300-nm in both in vitro and in vivo images. Cracks and fractures also interfered with light propagation in the tooth aiding in crack identification and assessment of depth and severity.

Ground based mid-IR heterodyne spectrometer concept for planetary atmospheres observations

Science.gov (United States)

Garamov, V.; Benderov, O.; Semenov, V.; Spiridonov, M.; Rodin, A.; Stepanov, B.

2017-09-01

We present a heterodyne spectrometer concept based on distributed feedback (DFB) quantum cascade lasers (QCL) operated in midle infrared region (MIR). The instrument is assumed to be mount on the Russian infrared observatories. The core features of the concept are compact design, utilizing a novel mid-IR fiber optical components and dynamic local oscillator frequency locking using reference molecule absorption line. The instrument characteristics are similar to modern heterodyne devices THIS (Cologne University, Germany) and MILAHI (Tohoku University, Japan) in terms of fundamental parameters, including spectral resolution, spectral coverage in a single observation. At present moment we created laboratory setup including all necessary elements of MIR heterodyne spectrometer. We have studied different components of noises of our system and found optimal value of LO power. The measured signal to noise ratio (SNR) with MCT PD was about 10 times greater than LO's shot noise (theoretical limit of heterodyne technique SNR) and limited by QCL relative intensity noise (RIN). However, applying additional filtering it is possible to reduce this value better than 5 shot noise level, which is typical to TEC cooled MCT PD. Also we demonstrate heterodyne signal measurements using laboratory black body with temperature of 400 oC.

Influence of composition and roughness on the pigment mapping of paintings using mid-infrared fiberoptics reflectance spectroscopy (mid-IR FORS) and multivariate calibration.

Science.gov (United States)

Sessa, Clarimma; Bagán, Héctor; García, Jose Francisco

2014-10-01

Mid-infrared fiberoptics reflectance spectroscopy (mid-IR FORS) is a very interesting technique for artwork characterization purposes. However, the fact that the spectra obtained are a mixture of surface (specular) and volume (diffuse) reflection is a significant drawback. The physical and chemical features of the artwork surface may produce distortions in the spectra that hinder comparison with reference databases acquired in transmission mode. Several studies attempted to understand the influence of the different variables and propose procedures to improve the interpretation of the spectra. This article is focused on the application of mid-IR FORS and multivariate calibration to the analysis of easel paintings. The objectives are the evaluation of the influence of the surface roughness on the spectra, the influence of the matrix composition for the classification of unknown spectra, and the capability of obtaining pigment composition mappings. A first evaluation of a fast procedure for spectra management and pigment discrimination is discussed. The results demonstrate the capability of multivariate methods, principal component analysis (PCA), and partial least squares discrimination analysis (PLS-DA), to model the distortions of the reflectance spectra and to delimitate and discriminate areas of uniform composition. The roughness of the painting surface is found to be an important factor affecting the shape and relative intensity of the spectra. A mapping of the major pigments of a painting is possible using mid-IR FORS and PLS-DA when the calibration set is a palette that includes the potential pigments present in the artwork mixed with the appropriate binder and that shows the different paint textures.

Phase-Sensitive Control Of Molecular Dissociation Through Attosecond Pump/Strong-Field Mid-IR Probe Spectroscopy

Science.gov (United States)

2016-04-15

splitter (consisting of a thin, uncoated, silicon plate at brewsters angle) and the beams were focused onto the OPA crystal. For this work two...experiments in the future. These technologies include • Two-color driven (EUV/mid-IR) ion spectroscopy: we designed an interferometer combining EUV...isolated single-femtosecond EUV pulse generation: combining the use of low ionization threshold gas, an annual near-IR drive beam , polarization

Infrared upconversion hyperspectral imaging

DEFF Research Database (Denmark)

Kehlet, Louis Martinus; Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin

2015-01-01

In this Letter, hyperspectral imaging in the mid-IR spectral region is demonstrated based on nonlinear frequency upconversion and subsequent imaging using a standard Si-based CCD camera. A series of upconverted images are acquired with different phase match conditions for the nonlinear frequency...... conversion process. From this, a sequence of monochromatic images in the 3.2-3.4 mu m range is generated. The imaged object consists of a standard United States Air Force resolution target combined with a polystyrene film, resulting in the presence of both spatial and spectral information in the infrared...... image. (C) 2015 Optical Society of America...

MAPPING THE SPATIAL DISTRIBUTION OF DUST EXTINCTION IN NGC 959 USING BROADBAND VISIBLE AND MID-INFRARED FILTERS

International Nuclear Information System (INIS)

Tamura, K.; Jansen, R. A.; Windhorst, R. A.

2009-01-01

We present a method to estimate and map the two-dimensional distribution of dust extinction in the late-type spiral galaxy NGC 959 from the theoretical and observed flux ratio of optical V and mid-IR (MIR) 3.6 μm images. Our method is applicable to both young and old stellar populations for a range of metallicities, and is not restricted to lines of sight toward star-formation (SF) regions. We explore this method using a pixel-based analysis on images of NGC 959 obtained in the V band at the Vatican Advanced Technology Telescope and at 3.6 μm (L band) with Spitzer/Infrared Array Camera. We present the original and extinction corrected Galaxy Evolution Explorer (GALEX) far-UV (FUV) and near-UV (NUV) images, as well as optical UBVR images of NGC 959. While the dust lanes are not clearly evident at GALEX resolution, our dust map clearly traces the dust that can be seen silhouetted against the galaxy's disk in the high-resolution Hubble Space Telescope (HST) images of NGC 959. The advantages of our method are (1) it only depends on two relatively common broadband images in the optical V band and in the MIR at 3.6 μm (but adding a near-UV band improves its fidelity); and (2) it is able to map the two-dimensional spatial distribution of dust within a galaxy. This powerful tool could be used to measure the detailed distribution of dust extinction within higher redshift galaxies to be observed with, e.g., the Hubble Space Telescope (HST)/WFC3 (optical near-IR) and James Webb Space Telescope (mid-IR), and to distinguish properties of dust within galaxy bulges, spiral arms, and inter-arm regions.

Classification of edible oils and modeling of their physico-chemical properties by chemometric methods using mid-IR spectroscopy

Science.gov (United States)

Luna, Aderval S.; da Silva, Arnaldo P.; Ferré, Joan; Boqué, Ricard

This research work describes two studies for the classification and characterization of edible oils and its quality parameters through Fourier transform mid infrared spectroscopy (FT-mid-IR) together with chemometric methods. The discrimination of canola, sunflower, corn and soybean oils was investigated using SVM-DA, SIMCA and PLS-DA. Using FT-mid-IR, DPLS was able to classify 100% of the samples from the validation set, but SIMCA and SVM-DA were not. The quality parameters: refraction index and relative density of edible oils were obtained from reference methods. Prediction models for FT-mid-IR spectra were calculated for these quality parameters using partial least squares (PLS) and support vector machines (SVM). Several preprocessing alternatives (first derivative, multiplicative scatter correction, mean centering, and standard normal variate) were investigated. The best result for the refraction index was achieved with SVM as well as for the relative density except when the preprocessing combination of mean centering and first derivative was used. For both of quality parameters, the best results obtained for the figures of merit expressed by the root mean square error of cross validation (RMSECV) and prediction (RMSEP) were equal to 0.0001.

High-resolution T1-weighted 3D real IR imaging of the temporal bone using triple-dose contrast material

Energy Technology Data Exchange (ETDEWEB)

Naganawa, Shinji; Koshikawa, Tokiko; Nakamura, Tatsuya; Fukatsu, Hiroshi; Ishigaki, Takeo [Department of Radiology, Nagoya University School of Medicine, 65 Tsurumai-cho, Shouwa-ku, 466-8550, Nagoya (Japan); Aoki, Ikuo [Medical System Company, Toshiba Corporation, Tokyo (Japan)

2003-12-01

The small structures in the temporal bone are surrounded by bone and air. The objectives of this study were (a) to compare contrast-enhanced T1-weighted images acquired by fast spin-echo-based three-dimensional real inversion recovery (3D rIR) against those acquired by gradient echo-based 3D SPGR in the visualization of the enhancement of small structures in the temporal bone, and (b) to determine whether either 3D rIR or 3D SPGR is useful for visualizing enhancement of the cochlear lymph fluid. Seven healthy men (age range 27-46 years) volunteered to participate in this study. All MR imaging was performed using a dedicated bilateral quadrature surface phased-array coil for temporal bone imaging at 1.5 T (Visart EX, Toshiba, Tokyo, Japan). The 3D rIR images (TR/TE/TI: 1800 ms/10 ms/500 ms) and flow-compensated 3D SPGR images (TR/TE/FA: 23 ms/10 ms/25 ) were obtained with a reconstructed voxel size of 0.6 x 0.7 x 0.8 mm{sup 3}. Images were acquired before and 1, 90, 180, and 270 min after the administration of triple-dose Gd-DTPA-BMA (0.3 mmol/kg). In post-contrast MR images, the degree of enhancement of the cochlear aqueduct, endolymphatic sac, subarcuate artery, geniculate ganglion of the facial nerve, and cochlear lymph fluid space was assessed by two radiologists. The degree of enhancement was scored as follows: 0 (no enhancement); 1 (slight enhancement); 2 (intermediate between 1 and 3); and 3 (enhancement similar to that of vessels). Enhancement scores for the endolymphatic sac, subarcuate artery, and geniculate ganglion were higher in 3D rIR than in 3D SPGR. Washout of enhancement in the endolymphatic sac appeared to be delayed compared with that in the subarcuate artery, suggesting that the enhancement in the endolymphatic sac may have been due in part to non-vascular tissue enhancement. Enhancement of the cochlear lymph space was not observed in any of the subjects in 3D rIR and 3D SPGR. The 3D rIR sequence may be more sensitive than the 3D SPGR sequence in

Mid IR-fiber spectroscopy in the 2-17μm range

Science.gov (United States)

Artyushenko, Viatcheslav G.; Bocharnikov, A.; Colquhoun, Gary; Leach, Clive A.; Lobachov, Vladimir; Pirogova, Lyudmila; Sakharova, Tatjana; Savitskij, Dmitrij; Ezhevskaya, Tatjana; Bublikov, Alexandr

2007-10-01

The latest development in IR-fibre optics enables us to expand the spectral range of process spectroscopy from 2μm out to 17μm (5000 to 600cm-1) i.e. into the most informative "finger-print" part of the spectrum. Mid-IR wavelength ranges from 2 to 6-10μm may be covered by Chalcogenide IR-glass CIR-fibres while Polycrystalline PIR-fibres made of Silver Halides solid solutions transmit 4-17 μm wavelength radiation. PIR-fibre immersion ATR probes and Transmission/Reflection probes had been manufactured and successfully tested with different FTIR spectrometers in the field of remote spectroscopy for forensic substances identification, chemical reaction control, and monitoring of exhaust or exhalation gases. Using these techniques no sample preparation is necessary for fibre probes to measure evanescent, reflection and transmission spectra, in situ and in real time. QCL spectrometer may be used as a portable device for multispectral gas analysis at 1ppb level of detectivity for various applications in environmental pollution monitoring.

Mid-IR and far-IR investigation of AgI-doped silver diborate glasses

International Nuclear Information System (INIS)

Hudgens, J.J.; Martin, S.W.

1996-01-01

The structures of xAgI+(1-x)Ag 2 O·2B 2 O 3 glasses, where 0.2≤x≤0.6, have been investigated using mid- and far-infrared spectroscopy. The mid-IR spectra revealed that in those glasses prepared using AgNO 3 as the starting material for Ag 2 O, the BO 4 - /BO 3 ratio is constant with increasing amounts of AgI as would be expected form the proposed behavior of AgI in these glasses. However, a survey of the literature revealed those glasses prepared from pure Ag 2 O show a strong linear dependence of the BO 4 - /BO 3 ratio on AgI content. Most probably, in those glasses prepared with Ag 2 O the Ag 2 O/B 2 O 3 ratio changes with AgI content due to the decomposition of Ag 2 O during melting. This different behavior is associated with AgNO 3 decomposing to Ag 2 O with heating followed by incorporation into the glassy network. For Ag 2 O used directly, it is proposed that it decomposes to Ag metal and O 2 (gas) with heating before it can be incorporated into the borate network. This latter behavior decreases with increasing AgI in the batch composition because AgI lowers the liquidus temperature of the melt considerably. The far-IR analysis of the AgI-doped silver diborate glasses suggests that there are three coordination environments for the Ag + ions; one with iodide anions and the other two with oxygen ions. It is proposed that the separate oxygen coordination environments for the Ag + ions arise from one with bridging oxygens of BO 4 - units, and the other with nonbridging oxygens on BO 3 - units. Furthermore, it is proposed that the Ag + ions in the iodide-ion environments progressively agglomerate into disordered regions of AgI, but do not form structures similar to α-AgI. (Abstract Truncated)

High-z X-ray Obscured Quasars in Galaxies with Extreme Mid-IR/Optical Colors

Science.gov (United States)

Piconcelli, E.; Lanzuisi, G.; Fiore, F.; Feruglio, C.; Vignali, C.; Salvato, M.; Grappioni, C.

2009-05-01

Extreme Optical/Mid-IR color cuts have been used to uncover a population of dust-enshrouded, mid-IR luminous galaxies at high redshifts. Several lines of evidence point towards the presence of an heavily absorbed, possibly Compton-thick quasar at the heart of these systems. Nonetheless, the X-ray spectral properties of these intriguing sources still remain largely unexplored. Here we present an X-ray spectroscopic study of a large sample of 44 extreme dust-obscured galaxies (EDOGs) with F24 μm/FR>2000 and F24 μm>1.3 mJy selected from a 6 deg2 region in the SWIRE fields. The application of our selection criteria to a wide area survey has been capable of unveiling a population of X-ray luminous, absorbed z>1 quasars which is mostly missed in the traditional optical/X-ray surveys performed so far. Advances in the understanding of the X-ray properties of these recently-discovered sources by Simbol-X observations will be also discussed.

Fast high-resolution MR imaging using the snapshot-FLASH MR sequence

International Nuclear Information System (INIS)

Matthaei, D.; Haase, A.; Henrich, D.; Duhmke, E.

1990-01-01

Snapshot, fast low-angle short (FLASH) MR imaging using an accelerated FLASH-MR sequence provides MR images with measuring times far below 1 second. The short TE of this sequence prevents susceptibility artifacts in gradient-echo imaging. In this paper variations of the sequence are shown that provide high resolution images with T1-weighted IR, T2-weighted SE, and chemical shift (CHESS) contrast sequences. METHODS AND MATERIALS: A whole-body 2-T system (Bruker-Medizintechnik) were used in combination with a 60-cm gradient system (providing gradient strength of 5 mT/m) to study healthy volunteers. The measuring time for a 256 x 256 image matrix was 800 msec. This sequence has been used in combination with T1-weighted IR, T2-weighted SE, and CHESS variations

The MIRI Medium Resolution Spectrometer calibration pipeline

NARCIS (Netherlands)

Labiano, A.; Azzollini, R.; Bailey, J.; Beard, S.; Dicken, D.; García-Marín, M.; Geers, V.; Glasse, A.; Glauser, A.; Gordon, K.; Justtanont, K.; Klaassen, P.; Lahuis, F.; Law, D.; Morrison, J.; Müller, M.; Rieke, G.; Vandenbussche, B.; Wright, G.

2016-01-01

The Mid-Infrared Instrument (MIRI) Medium Resolution Spectrometer (MRS) is the only mid-IR Integral Field Spectrometer on board James Webb Space Telescope. The complexity of the MRS requires a very specialized pipeline, with some specific steps not present in other pipelines of JWST instruments,

New horizons for Supercontinuum light sources: from UV to mid-IR

DEFF Research Database (Denmark)

Thomsen, Carsten L.; Nielsen, Frederik Donbæk; Johansen, Jeppe

2013-01-01

Commercially available supercontinuum sources continue to experience a strong growth in a wide range of industrial and scientific applications. In addition, there is a significant research effort focused on extending the wavelength coverage both towards UV and Mid-IR. Broadband sources covering...... and novel pumping schemes, whereas shifting the spectrum further towards the UV has been based on sophisticated microstructure fiber designs. Here we present our latest developments in tailoring the power and spectral coverage of spatially coherent broadband supercontinuum sources....

A UV to mid-IR study of AGN selection

Energy Technology Data Exchange (ETDEWEB)

Chung, Sun Mi; Kochanek, Christopher S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Assef, Roberto [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Brown, Michael J. I. [School of Physics, Monash University, Clayton, Vic 3800 (Australia); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Jannuzi, Buell T. [Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Gonzalez, Anthony H. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Hickox, Ryan C. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Moustakas, John [Department of Physics and Astronomy, Siena College, 515 Loudon Road, Loudonville, NY 12211 (United States)

2014-07-20

We classify the spectral energy distributions (SEDs) of 431,038 sources in the 9 deg{sup 2} Boötes field of the NOAO Deep Wide-Field Survey (NDWFS). There are up to 17 bands of data available per source, including ultraviolet (GALEX), optical (NDWFS), near-IR (NEWFIRM), and mid-infrared (IRAC and MIPS) data, as well as spectroscopic redshifts for ∼20,000 objects, primarily from the AGN and Galaxy Evolution Survey. We fit galaxy, active galactic nucleus (AGN), stellar, and brown dwarf templates to the observed SEDs, which yield spectral classes for the Galactic sources and photometric redshifts and galaxy/AGN luminosities for the extragalactic sources. The photometric redshift precision of the galaxy and AGN samples are σ/(1 + z) = 0.040 and σ/(1 + z) = 0.169, respectively, with the worst 5% outliers excluded. On the basis of the χ{sub ν}{sup 2} of the SED fit for each SED model, we are able to distinguish between Galactic and extragalactic sources for sources brighter than I = 23.5 mag. We compare the SED fits for a galaxy-only model and a galaxy-AGN model. Using known X-ray and spectroscopic AGN samples, we confirm that SED fitting can be successfully used as a method to identify large populations of AGNs, including spatially resolved AGNs with significant contributions from the host galaxy and objects with the emission line ratios of 'composite' spectra. We also use our results to compare with the X-ray, mid-IR, optical color, and emission line ratio selection techniques. For an F-ratio threshold of F > 10, we find 16,266 AGN candidates brighter than I = 23.5 mag and a surface density of ∼1900 AGN deg{sup –2}.

A MID-INFRARED IMAGING SURVEY OF SUBMILLIMETER-SELECTED GALAXIES WITH THE SPITZER SPACE TELESCOPE

International Nuclear Information System (INIS)

Hainline, Laura J.; Blain, A. W.; Smail, Ian; Frayer, D. T.; Chapman, S. C.; Ivison, R. J.; Alexander, D. M.

2009-01-01

We present Spitzer-IRAC and MIPS mid-IR observations of a sample of 73 radio-detected submillimeter-selected galaxies (SMGs) with spectroscopic redshifts, the largest such sample published to date. From our data, we find that IRAC colors of SMGs are much more uniform as compared with rest-frame UV and optical colors, and z>1.5 SMGs tend to be redder in their mid-IR colors than both field galaxies and lower-z SMGs. However, the IRAC colors of the SMGs overlap those of field galaxies sufficiently that color-magnitude and color-color selection criteria suggested in the literature to identify SMG counterparts produce ambiguous counterparts within an 8'' radius in 20%-35% of cases. We use a rest-frame J-H versus H-K color-color diagram and a S 24 /S 8.0 versus S 8.0 /S 4.5 color-color diagram to determine that 13%-19% of our sample are likely to contain active galactic nuclei which dominate their mid-IR emission. We observe in the rest-frame JHK colors of our sample that the rest-frame near-IR emission of SMGs does not resemble that of the compact nuclear starburst observed in local ultraluminous IR galaxies and is consistent with more widely distributed star formation. We take advantage of the fact that many high-z galaxy populations selected at different wavelengths are detected by Spitzer to carry out a brief comparison of mid-IR properties of SMGs to UV-selected high-z galaxies, 24 μm-selected galaxies, and high-z radio galaxies, and find that SMGs have mid-IR fluxes and colors which are consistent with being more massive and more reddened than UV-selected galaxies, while the IRAC colors of SMGs are most similar to powerful high-z radio galaxies.

Generating mid-IR octave-spanning supercontinua and few-cycle pulses with solitons in phase-mismatched quadratic nonlinear crystals

DEFF Research Database (Denmark)

Bache, Morten; Guo, Hairun; Zhou, Binbin

2013-01-01

We discuss a novel method for generating octave-spanning supercontinua and few-cycle pulses in the important mid-IR wavelength range. The technique relies on strongly phase-mismatched cascaded second-harmonic generation (SHG) in mid-IR nonlinear frequency conversion crystals. Importantly we here...... of the promising crystals: in one case soliton pulse compression from 50 fs to 15 fs (1.5 cycles) at 3.0 μm is achieved, and at the same time a 3-cycle dispersive wave at 5.0 μm is formed that can be isolated using a long-pass filter. In another example we show that extremely broadband supercontinua can form...

Simple methods via Mid-IR or {sup 1}H NMR spectroscopy for the determination of the iodine value of vegetable oils

Energy Technology Data Exchange (ETDEWEB)

Shimamoto, Gustavo G.; Favaro, Martha M.A.; Tubino, Matthieu, E-mail: tubino@iqm.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Química

2015-07-01

Two methods for determining the iodine value in vegetable oils are described. One employs mid-infrared (mid-IR) spectroscopy and the other uses hydrogen nuclear magnetic resonance ({sup 1}H NMR). The determination of the iodine value is based on either the transmittance intensity of mid-IR signals or on the {sup 1}H NMR signal integration and multivariate calibration. Both of the methods showed adequate coefficients of determination (r{sup 2} = 0.9974 and 0.9978, respectively) when compared to Wijs method, which is recommended by the norm EN 14111. A statistical comparison between the results from the proposed methods and from Wijs method shows that both instrumental methods offer equivalent results and greater precision compared to Wijs method. The regressions obtained from the constructed models were considered statistically significant and useful for making predictions. The proposed methods present several advantages compared to Wijs method because they significantly reduce analysis time, reagent consumption and waste generation. Furthermore, an analyst can choose between the mid-IR or {sup 1}H NMR to determine the iodine value. (author)

Highly doped InP as a low loss plasmonic material for mid-IR region.

Science.gov (United States)

Panah, M E Aryaee; Takayama, O; Morozov, S V; Kudryavtsev, K E; Semenova, E S; Lavrinenko, A V

2016-12-12

We study plasmonic properties of highly doped InP in the mid-infrared (IR) range. InP was grown by metal-organic vapor phase epitaxy (MOVPE) with the growth conditions optimized to achieve high free electron concentrations by doping with silicon. The permittivity of the grown material was found by fitting the calculated infrared reflectance spectra to the measured ones. The retrieved permittivity was then used to simulate surface plasmon polaritons (SPPs) propagation on flat and structured surfaces, and the simulation results were verified in direct experiments. SPPs at the top and bottom interfaces of the grown epilayer were excited by the prism coupling. A high-index Ge hemispherical prism provides efficient coupling conditions of SPPs on flat surfaces and facilitates acquiring their dispersion diagrams. We observed diffraction into symmetry-prohibited diffraction orders stimulated by the excitation of surface plasmon-polaritons in a periodically structured epilayer. Characterization shows good agreement between the theory and experimental results and confirms that highly doped InP is an effective plasmonic material aiming it for applications in the mid-IR wavelength range.

Modulation transfer function cascade model for a sampled IR imaging system.

Science.gov (United States)

de Luca, L; Cardone, G

1991-05-01

The performance of the infrared scanning radiometer (IRSR) is strongly stressed in convective heat transfer applications where high spatial frequencies in the signal that describes the thermal image are present. The need to characterize more deeply the system spatial resolution has led to the formulation of a cascade model for the evaluation of the actual modulation transfer function of a sampled IR imaging system. The model can yield both the aliasing band and the averaged modulation response for a general sampling subsystem. For a line scan imaging system, which is the case of a typical IRSR, a rule of thumb that states whether the combined sampling-imaging system is either imaging-dependent or sampling-dependent is proposed. The model is tested by comparing it with other noncascade models as well as by ad hoc measurements performed on a commercial digitized IRSR.

A 1,000 Frames/s Programmable Vision Chip with Variable Resolution and Row-Pixel-Mixed Parallel Image Processors

Directory of Open Access Journals (Sweden)

Nanjian Wu

2009-07-01

Full Text Available A programmable vision chip with variable resolution and row-pixel-mixed parallel image processors is presented. The chip consists of a CMOS sensor array, with row-parallel 6-bit Algorithmic ADCs, row-parallel gray-scale image processors, pixel-parallel SIMD Processing Element (PE array, and instruction controller. The resolution of the image in the chip is variable: high resolution for a focused area and low resolution for general view. It implements gray-scale and binary mathematical morphology algorithms in series to carry out low-level and mid-level image processing and sends out features of the image for various applications. It can perform image processing at over 1,000 frames/s (fps. A prototype chip with 64 × 64 pixels resolution and 6-bit gray-scale image is fabricated in 0.18 mm Standard CMOS process. The area size of chip is 1.5 mm × 3.5 mm. Each pixel size is 9.5 μm × 9.5 μm and each processing element size is 23 μm × 29 μm. The experiment results demonstrate that the chip can perform low-level and mid-level image processing and it can be applied in the real-time vision applications, such as high speed target tracking.

Wide-band IR imaging in the NIR-MIR-FIR regions for in situ analysis of frescoes

Science.gov (United States)

Daffara, C.; Pezzati, L.; Ambrosini, D.; Paoletti, D.; Di Biase, R.; Mariotti, P. I.; Frosinini, C.

2011-06-01

Imaging methods offer several advantages in the field of conservation allowing to perform non-invasive inspection of works of art. In particular, non-invasive techniques based on imaging in different infrared (IR) regions are widely used for the investigation of paintings. Using radiation beyond the visible range, different characteristics of the inspected artwork may be revealed according to the bandwidth acquired. In this paper we present the recent results of a joint project among the two research institutes DIMEG and CNR-INO, and the restoration facility Opificio delle Pietre Dure, concerning the wide-band integration of IR imaging techniques, in the spectral ranges NIR 0.8-2.5 μm, MIR 3-5 μm, and FIR 8-12 μm, for in situ analysis of artworks. A joint, multi-mode use of reflection and thermal bands is proposed for the diagnostics of mural paintings, and it is demonstrated to be an effective tool in inspecting the layered structure. High resolution IR reflectography and, to a greater extent, IR imaging in the 3-5 μm band, are effectively used to characterize the superficial layer of the fresco and to analyze the stratigraphy of different pictorial layers. IR thermography in the 8-12 μm band is used to characterize the support deep structure. The integration of all the data provides a multi- layered and multi-spectral representation of the fresco that yields a comprehensive analysis.

A High-resolution Multi-wavelength Simultaneous Imaging System with Solar Adaptive Optics

Energy Technology Data Exchange (ETDEWEB)

Rao, Changhui; Zhu, Lei; Gu, Naiting; Rao, Xuejun; Zhang, Lanqiang; Bao, Hua; Kong, Lin; Guo, Youming; Zhong, Libo; Ma, Xue’an; Li, Mei; Wang, Cheng; Zhang, Xiaojun; Fan, Xinlong; Chen, Donghong; Feng, Zhongyi; Wang, Xiaoyun; Wang, Zhiyong, E-mail: gunaiting@ioe.ac.cn [The Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, P.O. Box 350, Shuangliu, Chengdu 610209, Sichuan (China)

2017-10-01

A high-resolution multi-wavelength simultaneous imaging system from visible to near-infrared bands with a solar adaptive optics system, in which seven imaging channels, including the G band (430.5 nm), the Na i line (589 nm), the H α line (656.3 nm), the TiO band (705.7 nm), the Ca ii IR line (854.2 nm), the He i line (1083 nm), and the Fe i line (1565.3 nm), are chosen, is developed to image the solar atmosphere from the photosphere layer to the chromosphere layer. To our knowledge, this is the solar high-resolution imaging system with the widest spectral coverage. This system was demonstrated at the 1 m New Vaccum Solar Telescope and the on-sky high-resolution observational results were acquired. In this paper, we will illustrate the design and performance of the imaging system. The calibration and the data reduction of the system are also presented.

New Mid-IR Lasers Based on Rare-Earth-Doped Sulfide and Chloride Materials

International Nuclear Information System (INIS)

Nostrand, M

2000-01-01

Applications in remote-sensing and military countermeasures have driven a need for compact, solid-state mid-IR lasers. Due to multi-phonon quenching, non-traditional hosts are needed to extend current solid-state, room-temperature lasing capabilities beyond ∼ 4 (micro)m. Traditional oxide and fluoride hosts have effective phonon energies in the neighborhood of 1000 cm -1 and 500 cm -1 , respectively. These phonons can effectively quench radiation above 2 and 4 (micro)m, respectively. Materials with lower effective phonon energies such as sulfides and chlorides are the logical candidates for mid-IR (4-10 (micro)m) operation. In this report, laser action is demonstrated in two such hosts, CaGa 2 S 4 and KPb 2 Cl 5 . The CaGa 2 S 4 :Dy 3+ laser operating at 4.3 (micro)m represents the first sulfide laser operating beyond 2 (micro)m. The KPb 2 Cl 5 :Dy 3+ laser operating at 2.4 (micro)m represents the first operation of a chloride-host laser in ambient conditions. Laser action is also reported for CaGa 2 S 4 :Dy 3+ at 2.4 (micro)m, CaGa 2 S 4 :Dy 3+ at 1.4 (micro)m, and KPb 2 Cl 5 :Nd 3+ at 1.06 (micro)m. Both host materials have been fully characterized, including lifetimes, absorption and emission cross sections, radiative branching ratios, and radiative quantum efficiencies. Radiative branching ratios and radiative quantum efficiencies have been determined both by the Judd-Ofelt method (which is based on absorption measurements), and by a novel method described herein which is based on emission measurements. Modeling has been performed to predict laser performance, and a new method to determine emission cross section from slope efficiency and threshold data is developed. With the introduction and laser demonstration of rare-earth-doped CaGa 2 S 4 and KPb 2 Cl 5 , direct generation of mid-IR laser radiation in a solid-state host has been demonstrated. In KPb 2 Cl 5 , predictions indicate that laser operation to 9 (micro)m may be possible, a wavelength previously

Synoptic Mid-IR Spectra ToO Novae

Science.gov (United States)

Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

2007-02-01

Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

Piezo activated mode tracking system for widely tunable mode-hop-free external cavity mid-IR semiconductor lasers

Science.gov (United States)

Wysocki, Gerard (Inventor); Tittel, Frank K. (Inventor); Curl, Robert F. (Inventor)

2010-01-01

A widely tunable, mode-hop-free semiconductor laser operating in the mid-IR comprises a QCL laser chip having an effective QCL cavity length, a diffraction grating defining a grating angle and an external cavity length with respect to said chip, and means for controlling the QCL cavity length, the external cavity length, and the grating angle. The laser of claim 1 wherein said chip may be tuned over a range of frequencies even in the absence of an anti-reflective coating. The diffraction grating is controllably pivotable and translatable relative to said chip and the effective QCL cavity length can be adjusted by varying the injection current to the chip. The laser can be used for high resolution spectroscopic applications and multi species trace-gas detection. Mode-hopping is avoided by controlling the effective QCL cavity length, the external cavity length, and the grating angle so as to replicate a virtual pivot point.

Preliminary investigations into macroscopic attenuated total reflection-fourier transform infrared imaging of intact spherical domains: spatial resolution and image distortion.

Science.gov (United States)

Everall, Neil J; Priestnall, Ian M; Clarke, Fiona; Jayes, Linda; Poulter, Graham; Coombs, David; George, Michael W

2009-03-01

This paper describes preliminary investigations into the spatial resolution of macro attenuated total reflection (ATR) Fourier transform infrared (FT-IR) imaging and the distortions that arise when imaging intact, convex domains, using spheres as an extreme example. The competing effects of shallow evanescent wave penetration and blurring due to finite spatial resolution meant that spheres within the range 20-140 microm all appeared to be approximately the same size ( approximately 30-35 microm) when imaged with a numerical aperture (NA) of approximately 0.2. A very simple model was developed that predicted this extreme insensitivity to particle size. On the basis of these studies, it is anticipated that ATR imaging at this NA will be insensitive to the size of intact highly convex objects. A higher numerical aperture device should give a better estimate of the size of small spheres, owing to superior spatial resolution, but large spheres should still appear undersized due to the shallow sampling depth. An estimate of the point spread function (PSF) was required in order to develop and apply the model. The PSF was measured by imaging a sharp interface; assuming an Airy profile, the PSF width (distance from central maximum to first minimum) was estimated to be approximately 20 and 30 microm for IR bands at 1600 and 1000 cm(-1), respectively. This work has two significant limitations. First, underestimation of domain size only arises when imaging intact convex objects; if surfaces are prepared that randomly and representatively section through domains, the images can be analyzed to calculate parameters such as domain size, area, and volume. Second, the model ignores reflection and refraction and assumes weak absorption; hence, the predicted intensity profiles are not expected to be accurate; they merely give a rough estimate of the apparent sphere size. Much further work is required to place the field of quantitative ATR-FT-IR imaging on a sound basis.

A new generic method for the semi-automatic extraction of river and road networks in low and mid-resolution satellite images

Energy Technology Data Exchange (ETDEWEB)

Grazzini, Jacopo [Los Alamos National Laboratory; Dillard, Scott [PNNL; Soille, Pierre [EC JRC

2010-10-21

This paper addresses the problem of semi-automatic extraction of road or hydrographic networks in satellite images. For that purpose, we propose an approach combining concepts arising from mathematical morphology and hydrology. The method exploits both geometrical and topological characteristics of rivers/roads and their tributaries in order to reconstruct the complete networks. It assumes that the images satisfy the following two general assumptions, which are the minimum conditions for a road/river network to be identifiable and are usually verified in low- to mid-resolution satellite images: (i) visual constraint: most pixels composing the network have similar spectral signature that is distinguishable from most of the surrounding areas; (ii) geometric constraint: a line is a region that is relatively long and narrow, compared with other objects in the image. While this approach fully exploits local (roads/rivers are modeled as elongated regions with a smooth spectral signature in the image and a maximum width) and global (they are structured like a tree) characteristics of the networks, further directional information about the image structures is incorporated. Namely, an appropriate anisotropic metric is designed by using both the characteristic features of the target network and the eigen-decomposition of the gradient structure tensor of the image. Following, the geodesic propagation from a given network seed with this metric is combined with hydrological operators for overland flow simulation to extract the paths which contain most line evidence and identify them with the target network.

Effects of Low Carbohydrate High Protein (LCHP) diet on atherosclerotic plaque phenotype in ApoE/LDLR-/- mice: FT-IR and Raman imaging.

Science.gov (United States)

Wrobel, T P; Marzec, K M; Chlopicki, S; Maślak, E; Jasztal, A; Franczyk-Żarów, M; Czyżyńska-Cichoń, I; Moszkowski, T; Kostogrys, R B; Baranska, M

2015-09-22

Low Carbohydrate High Protein (LCHP) diet displays pro-atherogenic effects, however, the exact mechanisms involved are still unclear. Here, with the use of vibrational imaging, such as Fourier transform infrared (FT-IR) and Raman (RS) spectroscopies, we characterize biochemical content of plaques in Brachiocephalic Arteries (BCA) from ApoE/LDLR(-/-) mice fed LCHP diet as compared to control, recomended by American Institute of Nutrition, AIN diet. FT-IR images were taken from 6-10 sections of BCA from each mice and were complemented with RS measurements with higher spatial resolution of chosen areas of plaque sections. In aortic plaques from LCHP fed ApoE/LDLR(-/-) mice, the content of cholesterol and cholesterol esters was increased, while that of proteins was decreased as evidenced by global FT-IR analysis. High resolution imaging by RS identified necrotic core/foam cells, lipids (including cholesterol crystals), calcium mineralization and fibrous cap. The decreased relative thickness of the outer fibrous cap and the presence of buried caps were prominent features of the plaques in ApoE/LDLR(-/-) mice fed LCHP diet. In conclusion, FT-IR and Raman-based imaging provided a complementary insight into the biochemical composition of the plaque suggesting that LCHP diet increased plaque cholesterol and cholesterol esters contents of atherosclerotic plaque, supporting the cholesterol-driven pathogenesis of LCHP-induced atherogenesis.

EU-FP7-iMARS: analysis of Mars multi-resolution images using auto-coregistration, data mining and crowd source techniques: A Mid-term Report

Science.gov (United States)

Muller, J.-P.; Yershov, V.; Sidiropoulos, P.; Gwinner, K.; Willner, K.; Fanara, L.; Waelisch, M.; van Gasselt, S.; Walter, S.; Ivanov, A.; Cantini, F.; Morley, J. G.; Sprinks, J.; Giordano, M.; Wardlaw, J.; Kim, J.-R.; Chen, W.-T.; Houghton, R.; Bamford, S.

2015-10-01

Understanding the role of different solid surface formation processes within our Solar System is one of the fundamental goals of planetary science research. There has been a revolution in planetary surface observations over the last 8 years, especially in 3D imaging of surface shape (down to resolutions of 10s of cms) and subsequent terrain correction of imagery from orbiting spacecraft. This has led to the potential to be able to overlay different epochs back to the mid-1970s. Within iMars, a processing system has been developed to generate 3D Digital Terrain Models (DTMs) and corresponding OrthoRectified Images (ORIs) fully automatically from NASA MRO HiRISE and CTX stereo-pairs which are coregistered to corresponding HRSC ORI/DTMs. In parallel, iMars has developed a fully automated processing chain for co-registering level-1 (EDR) images from all previous NASA orbital missions to these HRSC ORIs and in the case of HiRISE these are further co-registered to previously co-registered CTX-to-HRSC ORIs. Examples will be shown of these multi-resolution ORIs and the application of different data mining algorithms to change detection using these co-registered images. iMars has recently launched a citizen science experiment to evaluate best practices for future citizen scientist validation of such data mining processed results. An example of the iMars website will be shown along with an embedded Version 0 prototype of a webGIS based on OGC standards.

Analysis of the development of missile-borne IR imaging detecting technologies

Science.gov (United States)

Fan, Jinxiang; Wang, Feng

2017-10-01

Today's infrared imaging guiding missiles are facing many challenges. With the development of targets' stealth, new-style IR countermeasures and penetrating technologies as well as the complexity of the operational environments, infrared imaging guiding missiles must meet the higher requirements of efficient target detection, capability of anti-interference and anti-jamming and the operational adaptability in complex, dynamic operating environments. Missileborne infrared imaging detecting systems are constrained by practical considerations like cost, size, weight and power (SWaP), and lifecycle requirements. Future-generation infrared imaging guiding missiles need to be resilient to changing operating environments and capable of doing more with fewer resources. Advanced IR imaging detecting and information exploring technologies are the key technologies that affect the future direction of IR imaging guidance missiles. Infrared imaging detecting and information exploring technologies research will support the development of more robust and efficient missile-borne infrared imaging detecting systems. Novelty IR imaging technologies, such as Infrared adaptive spectral imaging, are the key to effectively detect, recognize and track target under the complicated operating and countermeasures environments. Innovative information exploring techniques for the information of target, background and countermeasures provided by the detection system is the base for missile to recognize target and counter interference, jamming and countermeasure. Modular hardware and software development is the enabler for implementing multi-purpose, multi-function solutions. Uncooled IRFPA detectors and High-operating temperature IRFPA detectors as well as commercial-off-the-shelf (COTS) technology will support the implementing of low-cost infrared imaging guiding missiles. In this paper, the current status and features of missile-borne IR imaging detecting technologies are summarized. The key

Jupiter's Mid-Infrared Aurora: Solar Connection and Minor Constituents

Science.gov (United States)

Kostiuk, Theodore; Livengood, T.A.; Fast, K.E.; Hewagama, T.; Schmilling, F.; Sonnabend, G.; Delgado, J.

2009-01-01

High spectral resolution in the 12 pin region of the polar regions of Jupiter reveal unique information on auroral phenomena and upper stratospheric composition. Polar aurorae in Jupiter's atmosphere radiate; throughout the electromagnetic spectrum from X-ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based. spectroscopic measurements of Jupiter's northern mid-IR aurora acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane, emission brightness and solar 10.7-cm radar flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high scalar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. The spectra measured contain features that cannot be attributed to ethane and are most likely spectra of minor constituents whose molecular bands overlap the v9 band of ethane. Possible candidates are allene, propane, and other higher order hydrocarbons. These features appear to be enhanced in the active polar regions. Laboratory measurements at comparable spectral resolution of spectra of candidate molecules will be used to identify the constituents. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the NASA/ESA Europa Jupiter System Mission.

Fat-suppressed fast spin-echo mid-TE (TE[effective]=34) MR images: comparison with fast spin-echo T2-weighted images for the diagnosis of tears and anatomic variants of the glenoid labrum

Energy Technology Data Exchange (ETDEWEB)

Tuite, M J [Dept. of Radiology, Univ. of Wisconsin School of Medicine, Madison (United States); University of Wisconsin Hospital and Clinics, Dept. of Radiology, Madison, WI (United States); Shinners, T J; Hollister, M C [Dept. of Radiology, Univ. of Wisconsin School of Medicine, Madison (United States); Orwin, J F [Dept. of Orthopedic Surgery, University of Wisconsin School of Medicine, Madison (United States)

1999-12-01

Objective. To compare the sensitivity, specificity, and accuracy of fat-suppressed fast spin-echo (FSE) mid-TE (TE[effective]=34) images with fat-suppressed FSE T2-weighted images for the diagnosis of labral abnormalities.Design and patients. The study included 27 consecutive patients who had axial fat-suppressed FSE T2-weighted and fat-suppressed FSE mid-TE MR images, and had labral abnormalities diagnosed at arthroscopy. The acquisition time was about 5 min for each sequence, but the mid-TE sequence allowed a higher spatial resolution than the T2-weighted images (256 x 256 versus 256 x 192). Twenty-eight age-matched patients with arthroscopically normal labra were included as a control group. The labrum was graded on the MR images as normal or abnormal separately by two musculoskeletal radiologists who were masked to the history and arthroscopic results. The surgical findings were used as the gold standard for calculating the sensitivity, specificity, and accuracy for interpreting the correct location of a labral abnormality. The sensitivity, specificity, and accuracy for the two sequences were compared with a McNemar test, and significance defined as P<0.05.Results. For observer 1, the sensitivity for labral abnormalities was 0.59 on the T2-weighted images, and 0.78 on the mid-TE images (P=0.12). The specificity was 0.54 for the T2-weighted, and 0.64 for the mid-TE images (P=0.51). The accuracy was 0.56 for the T2-weighted, and 0.71 for the mid-TE images (P=0.08). For observer 2, the sensitivity/specificity/accuracy was 0.67/0.93/0.80 for the T2-weighted, and 0.70/0.86/0.78 for the mid-TE images (all P>0.5).Conclusion. In this small study there is no statistically significant difference for demonstrating labral abnormalities between FSE T2-weighted images, and higher-resolution fat-suppressed FSE mid-TE (TE[effective]=34) images obtained with a similar acquisition time. Although there was a general trend toward higher sensitivity and accuracy with the mid

IR sensitivity enhancement of CMOS Image Sensor with diffractive light trapping pixels.

Science.gov (United States)

Yokogawa, Sozo; Oshiyama, Itaru; Ikeda, Harumi; Ebiko, Yoshiki; Hirano, Tomoyuki; Saito, Suguru; Oinoue, Takashi; Hagimoto, Yoshiya; Iwamoto, Hayato

2017-06-19

We report on the IR sensitivity enhancement of back-illuminated CMOS Image Sensor (BI-CIS) with 2-dimensional diffractive inverted pyramid array structure (IPA) on crystalline silicon (c-Si) and deep trench isolation (DTI). FDTD simulations of semi-infinite thick c-Si having 2D IPAs on its surface whose pitches over 400 nm shows more than 30% improvement of light absorption at λ = 850 nm and the maximum enhancement of 43% with the 540 nm pitch at the wavelength is confirmed. A prototype BI-CIS sample with pixel size of 1.2 μm square containing 400 nm pitch IPAs shows 80% sensitivity enhancement at λ = 850 nm compared to the reference sample with flat surface. This is due to diffraction with the IPA and total reflection at the pixel boundary. The NIR images taken by the demo camera equip with a C-mount lens show 75% sensitivity enhancement in the λ = 700-1200 nm wavelength range with negligible spatial resolution degradation. Light trapping CIS pixel technology promises to improve NIR sensitivity and appears to be applicable to many different image sensor applications including security camera, personal authentication, and range finding Time-of-Flight camera with IR illuminations.

Thermally controlled mid-IR band-gap engineering in all-glass chalcogenide microstructured fibers: a numerical study

DEFF Research Database (Denmark)

Barh, Ajanta; Varshney, Ravi K.; Pal, Bishnu P.

2017-01-01

Presence of photonic band-gap (PBG) in an all-glass low refractive index (RI) contrast chalcogenide (Ch) microstructured optical fibers (MOFs) is investigated numerically. The effect of external temperature on the position of band-gap is explored to realize potential fiber-based wavelength filters....... Then the temperature sensitivity of band-gaps is investigated to design fiber-based mid-IR wavelength filters/sensors....

Mid infra-red hyper-spectral imaging with bright super continuum source and fast acousto-optic tuneable filter for cytological applications

International Nuclear Information System (INIS)

Farries, Mark; Ward, Jon; Valle, Stefano; Stephens, Gary; Moselund, Peter; Van der Zanden, Koen; Napier, Bruce

2015-01-01

Mid-IR imaging spectroscopy has the potential to offer an effective tool for early cancer diagnosis. Current development of bright super-continuum sources, narrow band acousto-optic tunable filters and fast cameras have made feasible a system that can be used for fast diagnosis of cancer in vivo at point of care. The performance of a proto system that has been developed under the Minerva project is described. (paper)

Assessment of COTS IR image simulation tools for ATR development

Science.gov (United States)

Seidel, Heiko; Stahl, Christoph; Bjerkeli, Frode; Skaaren-Fystro, Paal

2005-05-01

Following the tendency of increased use of imaging sensors in military aircraft, future fighter pilots will need onboard artificial intelligence e.g. ATR for aiding them in image interpretation and target designation. The European Aeronautic Defence and Space Company (EADS) in Germany has developed an advanced method for automatic target recognition (ATR) which is based on adaptive neural networks. This ATR method can assist the crew of military aircraft like the Eurofighter in sensor image monitoring and thereby reduce the workload in the cockpit and increase the mission efficiency. The EADS ATR approach can be adapted for imagery of visual, infrared and SAR sensors because of the training-based classifiers of the ATR method. For the optimal adaptation of these classifiers they have to be trained with appropriate and sufficient image data. The training images must show the target objects from different aspect angles, ranges, environmental conditions, etc. Incomplete training sets lead to a degradation of classifier performance. Additionally, ground truth information i.e. scenario conditions like class type and position of targets is necessary for the optimal adaptation of the ATR method. In Summer 2003, EADS started a cooperation with Kongsberg Defence & Aerospace (KDA) from Norway. The EADS/KDA approach is to provide additional image data sets for training-based ATR through IR image simulation. The joint study aims to investigate the benefits of enhancing incomplete training sets for classifier adaptation by simulated synthetic imagery. EADS/KDA identified the requirements of a commercial-off-the-shelf IR simulation tool capable of delivering appropriate synthetic imagery for ATR development. A market study of available IR simulation tools and suppliers was performed. After that the most promising tool was benchmarked according to several criteria e.g. thermal emission model, sensor model, targets model, non-radiometric image features etc., resulting in a

Low contrast detectability and spatial resolution with model-based iterative reconstructions of MDCT images: a phantom and cadaveric study

Energy Technology Data Exchange (ETDEWEB)

Millon, Domitille; Coche, Emmanuel E. [Universite Catholique de Louvain, Department of Radiology and Medical Imaging, Cliniques Universitaires Saint Luc, Brussels (Belgium); Vlassenbroek, Alain [Philips Healthcare, Brussels (Belgium); Maanen, Aline G. van; Cambier, Samantha E. [Universite Catholique de Louvain, Statistics Unit, King Albert II Cancer Institute, Brussels (Belgium)

2017-03-15

To compare image quality [low contrast (LC) detectability, noise, contrast-to-noise (CNR) and spatial resolution (SR)] of MDCT images reconstructed with an iterative reconstruction (IR) algorithm and a filtered back projection (FBP) algorithm. The experimental study was performed on a 256-slice MDCT. LC detectability, noise, CNR and SR were measured on a Catphan phantom scanned with decreasing doses (48.8 down to 0.7 mGy) and parameters typical of a chest CT examination. Images were reconstructed with FBP and a model-based IR algorithm. Additionally, human chest cadavers were scanned and reconstructed using the same technical parameters. Images were analyzed to illustrate the phantom results. LC detectability and noise were statistically significantly different between the techniques, supporting model-based IR algorithm (p < 0.0001). At low doses, the noise in FBP images only enabled SR measurements of high contrast objects. The superior CNR of model-based IR algorithm enabled lower dose measurements, which showed that SR was dose and contrast dependent. Cadaver images reconstructed with model-based IR illustrated that visibility and delineation of anatomical structure edges could be deteriorated at low doses. Model-based IR improved LC detectability and enabled dose reduction. At low dose, SR became dose and contrast dependent. (orig.)

Ge22As20Se58 glass ultrafast laser inscribed waveguides for mid-IR integrated optics

DEFF Research Database (Denmark)

Morris, James M.; Mackenzie, Mark D.; Petersen, Christian Rosenberg

2018-01-01

Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero-dispersi...... ultrafast laser inscribed waveguide devices in GASIR-1 for mid-IR integrated optics applications. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.......Ultrafast laser inscription has been used to produce channel waveguides in Ge22As20Se58 glass (GASIR-1, Umicore N.V). The mode field diameter and waveguide losses at 2.94 mu m were measured along with the waveguide dispersion in the 1 to 4.5 mu m range, which is used to estimate the zero......-dispersion wavelength. Z-scan measurements of bulk samples have also been performed to determine the nonlinear refractive index. Finally, midIR supercontinuum generation has been shown when pumping the waveguides with femtosecond pulses centered at 4.6 mu m. Supercontinuum spanning approximately 4 mu m from 2.5 to 6...

Highly Stable, All-fiber, High Power ZBLAN Supercontinuum Source Reaching 4.75 µm used for Nanosecond mid-IR Spectroscopy

DEFF Research Database (Denmark)

Moselund, Peter M.; Petersen, Christian; Leick, Lasse

2013-01-01

We demonstrate compact all-fiber mid-IR supercontinuum generation up to 4.75 μm with 1.2 W output power during hundreds of hours. This source is applied to upconversion spectroscopy using the energy corresponding to a single pulse....

Method of forming half-tone test images in the IR spectrum

International Nuclear Information System (INIS)

Glebova, L.N.; Gridin, A.S.; Denisov, V.N.; Dmitriev, I.Yu.; Mochalov, I.V.; Chebotarev, S.A.

1992-01-01

Test charts in the form of half-tone IR images, including not only an image of the interference-producing background (the underlying earth's surface and clouds), but also the observation objects, are required for conducting bench tests on the noise immunity of modern optoelectronic equipment designed to solve observation problems under background-interference conditions. The simulation of extended half-tone IR images containing the high spatial frequencies of background formations having an appreciable dynamic range of reproducible radiances is a complex problem in technical and processing aspects. The use of phosphorus as visible-to-IR converters for the creation of IR-background simulators is shown to be possible in principle in this paper. 2 refs., 3 figs

SuperPixel based mid-level image description for image recognition

NARCIS (Netherlands)

Tasli, H.E.; Sicre, R.; Gevers, T.

2015-01-01

This study proposes a mid-level feature descriptor and aims to validate improvement on image classification and retrieval tasks. In this paper, we propose a method to explore the conventional feature extraction techniques in the image classification pipeline from a different perspective where

Development of pixellated Ir-TESs

International Nuclear Information System (INIS)

Zen, Nobuyuki; Takahashi, Hiroyuki; Kunieda, Yuichi; Dayanthi, Rathnayaka M.T.; Mori, Fumiakira; Fujita, Kaoru; Nakazawa, Masaharu; Fukuda, Daiji; Ohkubo, Masataka

2006-01-01

We have been developing Ir-based pixellated superconducting transition edge sensors (TESs). In the area of material or astronomical applications, the sensor with few eV energy resolution and over 1000 pixels imaging property is desired. In order to achieve this goal, we have been analyzing signals from pixellated TESs. In the case of a 20 pixel array of Ir-TESs, with 45 μmx45 μm pixel sizes, the incident X-ray signals have been classified into 16 groups. We have applied numerical signal analysis. On the one hand, the energy resolution of our pixellated TES is strongly degraded. However, using pulse shape analysis, we can dramatically improve the resolution. Thus, we consider that the pulse signal analysis will lead this device to be used as a practical photon incident position identifying TES

High Resolution Energetic X-ray Imager (HREXI)

Science.gov (United States)

Grindlay, Jonathan

We propose to design and build the first imaging hard X-ray detector system that incorporates 3D stacking of closely packed detector readouts in finely-spaced imaging arrays with their required data processing and control electronics. In virtually all imaging astronomical detectors, detector readout is done with flex connectors or connections that are not vertical but rather horizontal , requiring loss of focal plane area. For high resolution pixel detectors needed for high speed event-based X-ray imaging, from low energy applications (CMOS) with focusing X-ray telescopes, to hard X-ray applications with pixelated CZT for large area coded aperture telescopes, this new detector development offers great promise. We propose to extend our previous and current APRA supported ProtoEXIST program that has developed the first large area imaging CZT detectors and demonstrated their astrophysical capabilities on two successful balloon flight to a next generation High Resolution Energetic X-ray Imager (HREXI), which would incorporate microvia technology for the first time to connect the readout ASIC on each CZT crystal directly to its control and data processing system. This 3-dimensional stacking of detector and readout/control system means that large area (>2m2) imaging detector planes for a High Resolution Wide-field hard X-ray telescope can be built with initially greatly reduced detector gaps and ultimately with no gaps. This increases detector area, efficiency, and simplicity of detector integration. Thus higher sensitivity wide-field imagers will be possible at lower cost. HREXI will enable a post-Swift NASA mission such as the EREXS concept proposed to PCOS to be conducted as a future MIDEX mission. This mission would conduct a high resolution (<2 arcmin) , broad band (5 200 keV) hard X-ray survey of black holes on all scales with ~10X higher sensitivity than Swift. In the current era of Time Domain Astrophysics, such a survey capability, in conjunction with a nIR

Generation and application of ultrashort coherent mid-infrared electromagnetic radiation

Science.gov (United States)

Wandel, Scott

Particle accelerators are useful instruments that help address critical issues for the future development of nuclear energy. Current state-of-the-art accelerators based on conventional radio-frequency (rf) cavities are too large and expensive for widespread commercial use, and alternative designs must be considered for supplying relativistic beams to small-scale applications, including medical imaging, secu- rity screening, and scientific research in a university-scale laboratory. Laser-driven acceleration using micro-fabricated dielectric photonic structures is an attractive approach because such photonic microstructures can support accelerating fields that are 10 to 100 times higher than that of rf cavity-based accelerators. Dielectric laser accelerators (DLAs) use commercial lasers as a driving source, which are smaller and less expensive than the klystrons used to drive current rf-based accelerators. Despite the apparent need for compact and economical laser sources for laser-driven acceleration, the availability of suitable high-peak-power lasers that cover a broad spectral range is currently limited. To address the needs of several innovative acceleration mechanisms like DLA, it is proposed to develop a coherent source of mid-infrared (IR) electromagnetic radiation that can be implemented as a driving source of laser accelerators. The use of ultrashort mid-IR high peak power laser systems in various laser-driven acceleration schemes has shown the potential to greatly reduce the optical pump intensities needed to realize high acceleration gradients. The optical intensity needed to achieve a given ponderomotive potential is 25 times less when using a 5-mum mid-IR laser as compared to using a 1-mum near-IR solid-state laser. In addition, dielectric structure breakdown caused by multiphoton ionization can be avoided by using longer-wavelength driving lasers. Current mid-IR laser sources do not produce sufficiently short pulse durations, broad spectral bandwidths

Characterization of protein and carbohydrate mid-IR spectral features in crop residues

Science.gov (United States)

Xin, Hangshu; Zhang, Yonggen; Wang, Mingjun; Li, Zhongyu; Wang, Zhibo; Yu, Peiqiang

2014-08-01

To the best of our knowledge, a few studies have been conducted on inherent structure spectral traits related to biopolymers of crop residues. The objective of this study was to characterize protein and carbohydrate structure spectral features of three field crop residues (rice straw, wheat straw and millet straw) in comparison with two crop vines (peanut vine and pea vine) by using Fourier transform infrared spectroscopy (FTIR) technique with attenuated total reflectance (ATR). Also, multivariate analyses were performed on spectral data sets within the regions mainly related to protein and carbohydrate in this study. The results showed that spectral differences existed in mid-IR peak intensities that are mainly related to protein and carbohydrate among these crop residue samples. With regard to protein spectral profile, peanut vine showed the greatest mid-IR band intensities that are related to protein amide and protein secondary structures, followed by pea vine and the rest three field crop straws. The crop vines had 48-134% higher spectral band intensity than the grain straws in spectral features associated with protein. Similar trends were also found in the bands that are mainly related to structural carbohydrates (such as cellulosic compounds). However, the field crop residues had higher peak intensity in total carbohydrates region than the crop vines. Furthermore, spectral ratios varied among the residue samples, indicating that these five crop residues had different internal structural conformation. However, multivariate spectral analyses showed that structural similarities still exhibited among crop residues in the regions associated with protein biopolymers and carbohydrate. Further study is needed to find out whether there is any relationship between spectroscopic information and nutrition supply in various kinds of crop residue when fed to animals.

High-speed high-sensitivity infrared spectroscopy using mid-infrared swept lasers (Conference Presentation)

Science.gov (United States)

Childs, David T. D.; Groom, Kristian M.; Hogg, Richard A.; Revin, Dmitry G.; Cockburn, John W.; Rehman, Ihtesham U.; Matcher, Stephen J.

2016-03-01

Infrared spectroscopy is a highly attractive read-out technology for compositional analysis of biomedical specimens because of its unique combination of high molecular sensitivity without the need for exogenous labels. Traditional techniques such as FTIR and Raman have suffered from comparatively low speed and sensitivity however recent innovations are challenging this situation. Direct mid-IR spectroscopy is being speeded up by innovations such as MEMS-based FTIR instruments with very high mirror speeds and supercontinuum sources producing very high sample irradiation levels. Here we explore another possible method - external cavity quantum cascade lasers (EC-QCL's) with high cavity tuning speeds (mid-IR swept lasers). Swept lasers have been heavily developed in the near-infrared where they are used for non-destructive low-coherence imaging (OCT). We adapt these concepts in two ways. Firstly by combining mid-IR quantum cascade gain chips with external cavity designs adapted from OCT we achieve spectral acquisition rates approaching 1 kHz and demonstrate potential to reach 100 kHz. Secondly we show that mid-IR swept lasers share a fundamental sensitivity advantage with near-IR OCT swept lasers. This makes them potentially able to achieve the same spectral SNR as an FTIR instrument in a time x N shorter (N being the number of spectral points) under otherwise matched conditions. This effect is demonstrated using measurements of a PDMS sample. The combination of potentially very high spectral acquisition rates, fundamental SNR advantage and the use of low-cost detector systems could make mid-IR swept lasers a powerful technology for high-throughput biomedical spectroscopy.

Next-generation mid-infrared sources

Science.gov (United States)

Jung, D.; Bank, S.; Lee, M. L.; Wasserman, D.

2017-12-01

The mid-infrared (mid-IR) is a wavelength range with a variety of technologically vital applications in molecular sensing, security and defense, energy conservation, and potentially in free-space communication. The recent development and rapid commercialization of new coherent mid-infrared sources have spurred significant interest in the development of mid-infrared optical systems for the above applications. However, optical systems designers still do not have the extensive optical infrastructure available to them that exists at shorter wavelengths (for instance, in the visible and near-IR/telecom wavelengths). Even in the field of optoelectronic sources, which has largely driven the growing interest in the mid-infrared, the inherent limitations of state-of-the-art sources and the gaps in spectral coverage offer opportunities for the development of new classes of lasers, light emitting diodes and emitters for a range of potential applications. In this topical review, we will first present an overview of the current state-of-the-art mid-IR sources, in particular thermal emitters, which have long been utilized, and the relatively new quantum- and interband-cascade lasers, as well as the applications served by these sources. Subsequently, we will discuss potential mid-infrared applications and wavelength ranges which are poorly served by the current stable of mid-IR sources, with an emphasis on understanding the fundamental limitations of the current source technology. The bulk of the manuscript will then explore both past and recent developments in mid-infrared source technology, including narrow bandgap quantum well lasers, type-I and type-II quantum dot materials, type-II superlattices, highly mismatched alloys, lead-salts and transition-metal-doped II-VI materials. We will discuss both the advantages and limitations of each of the above material systems, as well as the potential new applications which they might serve. All in all, this topical review does not aim

Ultra-Broadband Infrared Pulses from a Potassium-Titanyl Phosphate Optical Parametric Amplifier for VIS-IR-SFG Spectroscopy

Science.gov (United States)

Isaienko, Oleksandr; Borguet, Eric

A non-collinear KTP-OPA to provide ultra-broadband mid-infrared pulses was designed and characterized. With proper pulse-front and phase correction, the system has a potential for high-time resolution vibrational VIS-IR-SFG spectroscopy.

Mid-IR femtosecond frequency conversion by soliton-probe collision in phase-mismatched quadratic nonlinear crystals

DEFF Research Database (Denmark)

Liu, Xing; Zhou, Binbin; Guo, Hairun

2015-01-01

in a quadratic nonlinear crystal (beta-barium borate) in the normal dispersion regime due to cascaded (phase-mismatched) second-harmonic generation, and the mid-IR converted wave is formed in the anomalous dispersion regime between. lambda = 2.2-2.4 mu m as a resonant dispersive wave. This process relies...... on nondegenerate four-wave mixing mediated by an effective negative cross-phase modulation term caused by cascaded soliton-probe sum-frequency generation. (C) 2015 Optical Society of America...

Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses

DEFF Research Database (Denmark)

Bache, Morten; Bang, Ole; Zhou, Binbin

2011-01-01

When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the λ = 2...

High Resolution Near-IR Imaging of VY Canis Majoris with LBT / LMIRCam (2 - 5 μm)

Science.gov (United States)

Shenoy, Dinesh; Jones, T. J.; Humphreys, R. M.; LMIRCam Instrument Team

2013-06-01

HST imaging of the famous red hypergiant VY Canis Majoris shows a complex circumstellar reflection nebula indicative of multiple asymmetric ejection episodes. Constructing a more complete picture of the mass loss mechanism compels extending high resolution imaging of massive stars such as VY CMa into the near-infrared, where the mechanism for emission from circumstellar ejecta transitions from scattering to thermal. We present LBT/LMIRCam observations of VY CMa at Ks (2.2 μm), L' (3.8 μm) and M (4.9 μm) at sub-arcsecond resolution, comparable to the HST in the optical. The peculiar Southwest (SW) Clump, first identified as a highly reddened feature seen only at the longest wavelength (1 μm) in the HST images, appears bright in the three LMIRCam filters. The SW Clump is found to be optically thick at all three wavelengths. A silicate grain model yields a lower limit mass on the order of 7E-4 M⊙

Development of pixellated Ir-TESs

Science.gov (United States)

Zen, Nobuyuki; Takahashi, Hiroyuki; Kunieda, Yuichi; Damayanthi, Rathnayaka M. T.; Mori, Fumiakira; Fujita, Kaoru; Nakazawa, Masaharu; Fukuda, Daiji; Ohkubo, Masataka

2006-04-01

We have been developing Ir-based pixellated superconducting transition edge sensors (TESs). In the area of material or astronomical applications, the sensor with few eV energy resolution and over 1000 pixels imaging property is desired. In order to achieve this goal, we have been analyzing signals from pixellated TESs. In the case of a 20 pixel array of Ir-TESs, with 45 μm×45 μm pixel sizes, the incident X-ray signals have been classified into 16 groups. We have applied numerical signal analysis. On the one hand, the energy resolution of our pixellated TES is strongly degraded. However, using pulse shape analysis, we can dramatically improve the resolution. Thus, we consider that the pulse signal analysis will lead this device to be used as a practical photon incident position identifying TES.

Depth-resolution imaging of crystalline nanoclusters attached on and embedded in amorphous films using aberration-corrected TEM

Energy Technology Data Exchange (ETDEWEB)

Yamasaki, Jun, E-mail: yamasaki@uhvem.osaka-u.ac.jp [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Mori, Masayuki [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Hirata, Akihiko [Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Hirotsu, Yoshihiko [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Tanaka, Nobuo [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2015-04-15

For observations of crystalline nanoclusters, the features and capabilities of depth-resolution imaging by aberration-corrected transmission electron microscopy (TEM) were investigated using image simulations and experiments for two types of samples. The first sample was gold clusters attached on an amorphous carbon film. The experimental through-focal series indicated that the focal plane for the cluster was shifted 3 nm from that for the supporting film. This difference is due to the depth-resolution imaging of the cluster and film, the mid-planes of which are separated by 3 nm along the depth direction (the electron incident direction). On the basis of this information, the three-dimensional configuration of the sample, such as the film thickness of 2 nm, was successfully illustrated. The second sample was a Zr{sub 66.7}Ni{sub 33.3} metallic glass including a medium-range-order (MRO) structure, which was approximately considered to be a crystalline cluster with a diameter of 1.6 nm. In the experimental through-focal series, the lattice fringe of the MRO cluster was visible at limited focal conditions. Image simulations reproduced well the focal conditions and also indicated a structural condition for the visualization that the embedded cluster must be apart from the mid-plane of the matrix film. Similar to the case of the first sample, this result can be explained by the idea that the “effective focal planes” for the film and cluster are at different heights. This type of depth-resolution phase contrast imaging is possible only in aberration-corrected TEM and when the sample has a simple structure and is sufficiently thin for the kinematical scattering approximation. - Highlights: • Depth-resolution imaging by aberration-corrected TEM was demonstrated. • Thickness of a carbon film supporting gold nano-crystals was successfully estimated. • A crystalline nanocluster embedded in an amorphous matrix was successfully observed. • It was clarified that

FTIR measurements of mid-IR absorption spectra of gaseous fatty acid methyl esters at T=25–500 °C

International Nuclear Information System (INIS)

Campbell, M.F.; Freeman, K.G.; Davidson, D.F.; Hanson, R.K.

2014-01-01

Gas-phase mid-infrared (IR) absorption spectra (2500–3400 cm −1 ) for eleven fatty acid methyl esters (FAMEs) have been quantitatively measured at temperatures between 25 and 500 °C using an FTIR spectrometer with a resolution of 1 cm −1 . Using these spectra, the absorption cross section at 3.39 μm, corresponding to the monochromatic output of a helium–neon laser, is reported for each of these fuels as a function of temperature. The data indicate that the 3.39 μm cross section values of saturated FAMEs vary linearly with the logarithm of the number of C-H bonds in the molecule. - Highlights: • Infrared spectra of 11 fatty acid methyl esters (C 3 –C 11 ) have been measured. • A linear relationship for predicting 3.39 μm cross section values is proposed. • A molecule’s integrated area is linearly related to its number of C-H bonds. • Mono-unsaturation decreases cross section values

Solitonic supercontinuum of femtosecond mid-IR pulses in W-type index tellurite fibers with two zero dispersion wavelengths

Directory of Open Access Journals (Sweden)

S. Kedenburg

2016-11-01

Full Text Available We present a detailed experimental parameter study on mid-IR supercontinuum generation in W-type index tellurite fibers, which reveals how the core diameter, pump wavelength, fiber length, and pump power dramatically influence the spectral broadening. As pump source, we use femtosecond mid-IR pulses from a post-amplified optical parametric oscillator tunable between 1.7 μm and 4.1 μm at 43 MHz repetition rate. We are able to generate red-shifted dispersive waves up to a wavelength of 5.1 μm by pumping a tellurite fiber in the anomalous dispersion regime between its two zero dispersion wavelengths. Distinctive soliton dynamics can be identified as the main broadening mechanism resulting in a maximum spectral width of over 2000 nm with output powers of up to 160 mW. We experimentally demonstrated that efficient spectral broadening with considerably improved power proportion in the important first atmospheric transmission window between 3 and 5 μm can be achieved in robust W-type tellurite fibers pumped at long wavelengths by ultra-fast lasers.

About possibility of temperature trace observing on a human skin through clothes by using computer processing of IR image

Science.gov (United States)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Shestakov, Ivan L.; Blednov, Roman G.

2017-05-01

One of urgent security problems is a detection of objects placed inside the human body. Obviously, for safety reasons one cannot use X-rays for such object detection widely and often. For this purpose, we propose to use THz camera and IR camera. Below we continue a possibility of IR camera using for a detection of temperature trace on a human body. In contrast to passive THz camera using, the IR camera does not allow to see very pronounced the object under clothing. Of course, this is a big disadvantage for a security problem solution based on the IR camera using. To find possible ways for this disadvantage overcoming we make some experiments with IR camera, produced by FLIR Company and develop novel approach for computer processing of images captured by IR camera. It allows us to increase a temperature resolution of IR camera as well as human year effective susceptibility enhancing. As a consequence of this, a possibility for seeing of a human body temperature changing through clothing appears. We analyze IR images of a person, which drinks water and eats chocolate. We follow a temperature trace on human body skin, caused by changing of temperature inside the human body. Some experiments are made with observing of temperature trace from objects placed behind think overall. Demonstrated results are very important for the detection of forbidden objects, concealed inside the human body, by using non-destructive control without using X-rays.

Mid-IR absorption sensing of heavy water using a silicon-on-sapphire waveguide.

Science.gov (United States)

Singh, Neetesh; Casas-Bedoya, Alvaro; Hudson, Darren D; Read, Andrew; Mägi, Eric; Eggleton, Benjamin J

2016-12-15

We demonstrate a compact silicon-on-sapphire (SOS) strip waveguide sensor for mid-IR absorption spectroscopy. This device can be used for gas and liquid sensing, especially to detect chemically similar molecules and precisely characterize extremely absorptive liquids that are difficult to detect by conventional infrared transmission techniques. We reliably measure concentrations up to 0.25% of heavy water (D2O) in a D2O-H2O mixture at its maximum absorption band at around 4 μm. This complementary metal-oxide-semiconductor (CMOS) compatible SOS D2O sensor is promising for applications such as measuring body fat content or detection of coolant leakage in nuclear reactors.

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

Energy Technology Data Exchange (ETDEWEB)

Kotasidis, Fotis A. [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom); Angelis, Georgios I. [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia); Anton-Rodriguez, Jose; Matthews, Julian C. [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom); Reader, Andrew J. [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King' s College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland); Geneva Neuroscience Centre, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30 001, Groningen 9700 RB (Netherlands)

2014-05-15

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

International Nuclear Information System (INIS)

Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

2014-01-01

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

Isotope specific resolution recovery image reconstruction in high resolution PET imaging.

Science.gov (United States)

Kotasidis, Fotis A; Angelis, Georgios I; Anton-Rodriguez, Jose; Matthews, Julian C; Reader, Andrew J; Zaidi, Habib

2014-05-01

Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution recovery image reconstruction. The

Mid-infrared materials and devices on a Si platform for optical sensing

Science.gov (United States)

Singh, Vivek; Lin, Pao Tai; Patel, Neil; Lin, Hongtao; Li, Lan; Zou, Yi; Deng, Fei; Ni, Chaoying; Hu, Juejun; Giammarco, James; Soliani, Anna Paola; Zdyrko, Bogdan; Luzinov, Igor; Novak, Spencer; Novak, Jackie; Wachtel, Peter; Danto, Sylvain; Musgraves, J David; Richardson, Kathleen; Kimerling, Lionel C; Agarwal, Anuradha M

2014-01-01

In this article, we review our recent work on mid-infrared (mid-IR) photonic materials and devices fabricated on silicon for on-chip sensing applications. Pedestal waveguides based on silicon are demonstrated as broadband mid-IR sensors. Our low-loss mid-IR directional couplers demonstrated in SiNx waveguides are useful in differential sensing applications. Photonic crystal cavities and microdisk resonators based on chalcogenide glasses for high sensitivity are also demonstrated as effective mid-IR sensors. Polymer-based functionalization layers, to enhance the sensitivity and selectivity of our sensor devices, are also presented. We discuss the design of mid-IR chalcogenide waveguides integrated with polycrystalline PbTe detectors on a monolithic silicon platform for optical sensing, wherein the use of a low-index spacer layer enables the evanescent coupling of mid-IR light from the waveguides to the detector. Finally, we show the successful fabrication processing of our first prototype mid-IR waveguide-integrated detectors. PMID:27877641

Detecting infrared luminescence and non-chemical signaling of living cells: single cell mid-IR spectroscopy in cryogenic environments

Science.gov (United States)

Pereverzev, Sergey

2017-02-01

Many life-relevant interaction energies are in IR range, and it is reasonable to believe that some biochemical reactions inside cells can results in emission of IR photons. Cells can use this emission for non-chemical and non-electrical signaling. Detecting weak infrared radiation from live cells is complicated because of strong thermal radiation background and absorption of radiation by tissues. A microfluidic device with live cells inside a vacuum cryogenic environment should suppress this background, and thereby permit observation of live cell auto-luminescence or signaling in the IR regime. One can make IR-transparent windows not emitting in this range, so only the cell and a small amount of liquid around it will emit infrared radiation. Currently mid-IR spectroscopy of single cells requires the use of a synchrotron source to measure absorption or reflection spectra. Decreasing of thermal radiation background will allow absorption and reflection spectroscopy of cells without using synchrotron light. Moreover, cell auto-luminescence can be directly measured. The complete absence of thermal background radiation for cryogenically cooled samples allows the use IR photon-sensitive detectors and obtaining single molecule sensitivity in IR photo-luminescence measurements. Due to low photon energies, photo-luminescence measurements will be non-distractive for pressures samples. The technique described here is based upon US patent 9366574.

FT-mid-IR spectroscopic investigation of fiber maturity and crystallinity at single boll level and a comparison with XRD approach

Science.gov (United States)

In previous study, we have reported the development of simple algorithms for determining fiber maturity and crystallinity from Fourier transform (FT) -mid-infrared (IR) measurement. Due to its micro-sampling feature, we were able to assess the fiber maturity and crystallinity at different portions o...

Multi-scale Adaptive Gain Control of IR Images

NARCIS (Netherlands)

Schutte, K.

1997-01-01

IR imagery tends to have a higher dynamic range then typical display devices such as a CRT. Global methods such as stretching and histogram equalization improve the visibility of many images, but some information in the images stays hidden for a human operator. This paper reports about the

THE ROLE OF THE ACCRETION DISK, DUST, AND JETS IN THE IR EMISSION OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

Energy Technology Data Exchange (ETDEWEB)

Mason, R. E. [Gemini Observatory, Northern Operations Center, 670 N. A' ohoku Place, Hilo, HI 96720 (United States); Ramos Almeida, C. [Instituto de Astrofísica de Canarias, C/Vía Láctea, s/n, E-38205 La Laguna, Tenerife (Spain); Levenson, N. A. [Gemini Observatory, Southern Operations Center, c/o AURA, Casilla 603, La Serena (Chile); Nemmen, R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Alonso-Herrero, A., E-mail: rmason@gemini.edu [Instituto de Física de Cantabria, CSIC-UC, Avenida de los Castros s/n, E-39005 Santander (Spain)

2013-11-10

We use recent high-resolution infrared (IR; 1-20 μm) photometry to examine the origin of the IR emission in low-luminosity active galactic nuclei (LLAGN). The data are compared with published model fits that describe the spectral energy distribution (SED) of LLAGN in terms of an advection-dominated accretion flow, truncated thin accretion disk, and jet. The truncated disk in these models is usually not luminous enough to explain the observed IR emission, and in all cases its spectral shape is much narrower than the broad IR peaks in the data. Synchrotron radiation from the jet appears to be important in very radio-loud nuclei, but the detection of strong silicate emission features in many objects indicates that dust must also contribute. We investigate this point by fitting the IR SED of NGC 3998 using dusty torus and optically thin (τ{sub mid-IR} ∼ 1) dust shell models. While more detailed modeling is necessary, these initial results suggest that dust may account for the nuclear mid-IR emission of many LLAGN.

A ZnGeP{sub 2} Optical Parametric Oscillator with Mid-IR Output Power 3 W Pumped by a Tm, Ho:GdVO{sub 4} Laser

Energy Technology Data Exchange (ETDEWEB)

Bao-Quan, Yao; Guo-Li, Zhu; You-Lun, Ju; Yue-Zhu, Wang [National Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, Harbin 150080 (China)

2009-02-15

We report an efficient mid-infrared optical parametric oscillator (OPO) pumped by a pulsed Tm,Ho-codoped GdVO4 laser. The 10-W Tm,Ho:GdVO4 laser pumped by a 801 nm diode produces 20ns pulses with a repetition rate of 10kHz at wavelength of 2.048 {mu}m. The ZnGeP{sub 2} (ZGP) OPO produces 15-ns pulses in the spectral regions 3.65-3.8 {mu}m and 4.45-4.65 {mu}m simultaneously. More than 3 W of mid-IR output power can be generated with a total OPO slope efficiency greater than 58% corresponding to incident 2 {mu}m pump power. The diode laser pump to mid-IR optical conversion efficiency is about 12%.

Enhanced modeling of band nonparabolicity with application to a mid-IR quantum cascade laser structure

International Nuclear Information System (INIS)

Vukovic, N; Radovanovic, J; Milanovic, V

2014-01-01

We analyze the influence of conduction-band nonparabolicity on bound electronic states in the active region of a quantum cascade laser (QCL). Our model assumes expansion of the conduction-band dispersion relation up to a fourth order in wavevector and use of a suitable second boundary condition at the interface of two III-V semiconductor layers. Numerical results, obtained by the transfer matrix method, are presented for two mid-infrared GaAs/Al 0.33 Ga 0.67 As QCL active regions, and they are in very good agreement with experimental data found in the literature. Comparison with a different nonparabolicity model is presented for the example of a GaAs/Al 0.38 Ga 0.62 As-based mid-IR QCL. Calculations have also been carried out for one THz QCL structure to illustrate the possible application of the model in the terahertz part of the spectrum. (paper)

Versatile mid-infrared frequency-comb referenced sub-Doppler spectrometer

Science.gov (United States)

Gambetta, A.; Vicentini, E.; Coluccelli, N.; Wang, Y.; Fernandez, T. T.; Maddaloni, P.; De Natale, P.; Castrillo, A.; Gianfrani, L.; Laporta, P.; Galzerano, G.

2018-04-01

We present a mid-IR high-precision spectrometer capable of performing accurate Doppler-free measurements with absolute calibration of the optical axis and high signal-to-noise ratio. The system is based on a widely tunable mid-IR offset-free frequency comb and a Quantum-Cascade-Laser (QCL). The QCL emission frequency is offset locked to one of the comb teeth to provide absolute-frequency calibration, spectral-narrowing, and accurate fine frequency tuning. Both the comb repetition frequency and QCL-comb offset frequency can be modulated to provide, respectively, slow- and fast-frequency-calibrated scanning capabilities. The characterisation of the spectrometer is demonstrated by recording sub-Doppler saturated absorption features of the CHF3 molecule at around 8.6 μm with a maximum signal-to-noise ratio of ˜7 × 103 in 10 s integration time, frequency-resolution of 160 kHz, and accuracy of less than 10 kHz.

Versatile mid-infrared frequency-comb referenced sub-Doppler spectrometer

Directory of Open Access Journals (Sweden)

A. Gambetta

2018-04-01

Full Text Available We present a mid-IR high-precision spectrometer capable of performing accurate Doppler-free measurements with absolute calibration of the optical axis and high signal-to-noise ratio. The system is based on a widely tunable mid-IR offset-free frequency comb and a Quantum-Cascade-Laser (QCL. The QCL emission frequency is offset locked to one of the comb teeth to provide absolute-frequency calibration, spectral-narrowing, and accurate fine frequency tuning. Both the comb repetition frequency and QCL-comb offset frequency can be modulated to provide, respectively, slow- and fast-frequency-calibrated scanning capabilities. The characterisation of the spectrometer is demonstrated by recording sub-Doppler saturated absorption features of the CHF3 molecule at around 8.6 μm with a maximum signal-to-noise ratio of ∼7 × 103 in 10 s integration time, frequency-resolution of 160 kHz, and accuracy of less than 10 kHz.

Correcting the effect of refraction and dispersion of light in FT-IR spectroscopic imaging in transmission through thick infrared windows.

Science.gov (United States)

Chan, K L Andrew; Kazarian, Sergei G

2013-01-15

Transmission mode is one of the most common sampling methods for FT-IR spectroscopic imaging because the spectra obtained generally have a reasonable signal-to-noise ratio. However, dispersion and refraction of infrared light occurs when samples are sandwiched between infrared windows or placed underneath a layer of liquid. Dispersion and refraction cause infrared light to focus with different focal lengths depending on the wavelength (wavenumber) of the light. As a result, images obtained are in focus only at a particular wavenumber while they are defocused at other wavenumber values. In this work, a solution to correct this spread of focus by means of adding a lens on top of the infrared transparent window, such that a pseudo hemisphere is formed, has been investigated. Through this lens (or pseudo hemisphere), refraction of light is removed and the light across the spectral range has the same focal depth. Furthermore, the lens acts as a solid immersion objective and an increase of both magnification and spatial resolution (by 1.4 times) is demonstrated. The spatial resolution was investigated using an USAF resolution target, showing that the Rayleigh criterion can be achieved, as well as a sample with a sharp polymer interface to indicate the spatial resolution that can be expected in real samples. The reported approach was used to obtain chemical images of cross sections of cancer tissue and hair samples sandwiched between infrared windows showing the versatility and applicability of the method. In addition to the improved spatial resolution, the results reported herein also demonstrate that the lens can reduce the effect of scattering near the edges of tissue samples. The advantages of the presented approach, obtaining FT-IR spectroscopic images in transmission mode with the same focus across all wavenumber values and simultaneous improvement in spatial resolution, will have wide implications ranging from studies of live cells to sorption of drugs into tissues.

High-resolution dynamic imaging and quantitative analysis of lung cancer xenografts in nude mice using clinical PET/CT.

Science.gov (United States)

Wang, Ying Yi; Wang, Kai; Xu, Zuo Yu; Song, Yan; Wang, Chu Nan; Zhang, Chong Qing; Sun, Xi Lin; Shen, Bao Zhong

2017-08-08

Considering the general application of dedicated small-animal positron emission tomography/computed tomography is limited, an acceptable alternative in many situations might be clinical PET/CT. To estimate the feasibility of using clinical PET/CT with [F-18]-fluoro-2-deoxy-D-glucose for high-resolution dynamic imaging and quantitative analysis of cancer xenografts in nude mice. Dynamic clinical PET/CT scans were performed on xenografts for 60 min after injection with [F-18]-fluoro-2-deoxy-D-glucose. Scans were reconstructed with or without SharpIR method in two phases. And mice were sacrificed to extracting major organs and tumors, using ex vivo γ-counting as a reference. Strikingly, we observed that the image quality and the correlation between the all quantitive data from clinical PET/CT and the ex vivo counting was better with the SharpIR reconstructions than without. Our data demonstrate that clinical PET/CT scanner with SharpIR reconstruction is a valuable tool for imaging small animals in preclinical cancer research, offering dynamic imaging parameters, good image quality and accurate data quatification.

THE MID-INFRARED AND NEAR-ULTRAVIOLET EXCESS EMISSIONS OF QUIESCENT GALAXIES ON THE RED SEQUENCE

International Nuclear Information System (INIS)

Ko, Jongwan; Lee, Jong Chul; Hwang, Ho Seong; Sohn, Young-Jong

2013-01-01

We study the mid-infrared (IR) and near-ultraviolet (UV) excess emissions of spectroscopically selected quiescent galaxies on the optical red sequence. We use the Wide-field Infrared Survey Explorer mid-IR and Galaxy Evolution Explorer near-UV data for a spectroscopic sample of galaxies in the Sloan Digital Sky Survey Data Release 7 to study the possible connection between quiescent red-sequence galaxies with and without mid-IR/near-UV excess. Among 648 12 μm detected quiescent red-sequence galaxies without Hα emission, 26% and 55% show near-UV and mid-IR excess emissions, respectively. When we consider only bright (M r n 4000 than those without mid-IR and near-UV excess emissions. We also find that mid-IR weighted mean stellar ages of quiescent red-sequence galaxies with mid-IR excess are larger than those with near-UV excess, and smaller than those without mid-IR and near-UV excess. The environmental dependence of the fraction of quiescent red-sequence galaxies with mid-IR and near-UV excess seems strong even though the trends of quiescent red-sequence galaxies with near-UV excess differ from those with mid-IR excess. These results indicate that the recent star formation traced by near-UV (∼< 1 Gyr) and mid-IR (∼< 2 Gyr) excess is not negligible among nearby, quiescent, red, early-type galaxies. We suggest a possible evolutionary scenario of quiescent red-sequence galaxies from quiescent red-sequence galaxies with near-UV excess to those with mid-IR excess to those without near-UV and mid-IR excess.

Simultaneous monitoring of ice accretion and thermography of an airfoil: an IR imaging methodology

International Nuclear Information System (INIS)

Mohseni, M; Frioult, M; Amirfazli, A

2012-01-01

A novel image analysis methodology based on infrared (IR) imaging was developed for simultaneous monitoring of ice accretion and thermography of airfoils. In this study, an IR camera was calibrated and used to measure the surface temperature of the energized airfoils, and monitor the ice accretion and growth pattern on the airfoils’ surfaces. The methodology comprises the automatic processing of a series of IR video frames with the purpose of detecting ice pattern evolution during the icing test period. A specially developed MATLAB code was used to detect the iced areas in the IR images, and simultaneously monitor surface temperature evolution of the airfoil during an icing test. Knowing the correlation between the icing pattern and surface temperature changes during an icing test is essential for energy efficient design of thermal icing mitigation systems. Processed IR images were also used to determine the ice accumulation rate on the airfoil's surface in a given icing test. The proposed methodology has been demonstrated to work successfully, since the optical images taken at the end of icing tests from the airfoils’ surfaces compared well with the processed IR images detecting the ice grown outward from the airfoils’ leading edge area. (paper)

Initial results of a new generation dual source CT system using only an in-plane comb filter for ultra-high resolution temporal bone imaging.

Science.gov (United States)

Meyer, Mathias; Haubenreisser, Holger; Raupach, Rainer; Schmidt, Bernhard; Lietzmann, Florian; Leidecker, Christianne; Allmendinger, Thomas; Flohr, Thomas; Schad, Lothar R; Schoenberg, Stefan O; Henzler, Thomas

2015-01-01

To prospectively evaluate radiation dose and image quality of a third generation dual-source CT (DSCT) without z-axis filter behind the patient for temporal bone CT. Forty-five patients were either examined on a first, second, or third generation DSCT in an ultra-high-resolution (UHR) temporal bone-imaging mode. On the third generation DSCT system, the tighter focal spot of 0.2 mm(2) removes the necessity for an additional z-axis-filter, leading to an improved z-axis radiation dose efficiency. Images of 0.4 mm were reconstructed using standard filtered-back-projection or iterative reconstruction (IR) technique for previous generations of DSCT and a novel IR algorithm for the third generation DSCT. Radiation dose and image quality were compared between the three DSCT systems. The statistically significantly highest subjective and objective image quality was evaluated for the third generation DSCT when compared to the first or second generation DSCT systems (all p generation examination as compared to the first and second generation DSCT. Temporal bone imaging without z-axis-UHR-filter and a novel third generation IR algorithm allows for significantly higher image quality while lowering effective dose when compared to the first two generations of DSCTs. • Omitting the z-axis-filter allows a reduction in radiation dose of 50% • A smaller focal spot of 0.2 mm (2) significantly improves spatial resolution • Ultra-high-resolution temporal-bone-CT helps to gain diagnostic information of the middle/inner ear.

IR imaging of blood circulation of patients with vascular disease

Science.gov (United States)

Wang, Hsin; Wade, Dwight R., Jr.; Kam, Jack

2004-04-01

We conducted a preliminary IR imaging study of blood circulation in patients with peripheral vascular diseases. Abnormal blood flow is common in older adults, especially those with elevated blood lipids, diabetes, hypertension, and a history of smoking. All of these conditions have a high prevalence in our population, often with more than one condition in the same individual. The differences in blood flow is revealed by temperature differences in areas of the extremities as well as other regions of the body. However, what is needed is an imaging technique that is relatively inexpensive and can reveal the blood flow in real time. The IR imaging can show detailed venous system and small tempearture changes associated with blood flow. Six patients with vascular diseases were tested in a clinic set up. Their legs and feet were imaged. We observed large temperature differences (cooling of more than 10° C) at the foot, especially toes. More valuable information were obtained from the temperature distribution maps. IR thermography is potentially a very valuable tool for medical application, especially for vascular diseases.

Preliminary design of a tangentially viewing imaging bolometer for NSTX-U

Energy Technology Data Exchange (ETDEWEB)

Peterson, B. J., E-mail: peterson@LHD.nifs.ac.jp; Mukai, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); SOKENDAI (The Graduate University for Advance Studies), Toki 509-5292 (Japan); Sano, R. [National Institutes for Quantum and Radiological Science and Technology, Naka, Ibaraki 311-0193 (Japan); Reinke, M. L.; Canik, J. M.; Lore, J. D.; Gray, T. K. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Delgado-Aparicio, L. F.; Jaworski, M. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Eden, G. G. van [FOM Institute DIFFER, 5612 AJ Eindhoven (Netherlands)

2016-11-15

The infrared imaging video bolometer (IRVB) measures plasma radiated power images using a thin metal foil. Two different designs with a tangential view of NSTX-U are made assuming a 640 × 480 (1280 × 1024) pixel, 30 (105) fps, 50 (20) mK, IR camera imaging the 9 cm × 9 cm × 2 μm Pt foil. The foil is divided into 40 × 40 (64 × 64) IRVB channels. This gives a spatial resolution of 3.4 (2.2) cm on the machine mid-plane. The noise equivalent power density of the IRVB is given as 113 (46) μW/cm{sup 2} for a time resolution of 33 (20) ms. Synthetic images derived from Scrape Off Layer Plasma Simulation data using the IRVB geometry show peak signal levels ranging from ∼0.8 to ∼80 (∼0.36 to ∼26) mW/cm{sup 2}.

Femtosecond visible/visible and visible/mid-IR pump-probe study of the photosystem II core antenna complex CP47

NARCIS (Netherlands)

Groot, M.L.; Breton, J.; van Wilderen, L.; Dekker, J.P.; van Grondelle, R.

2004-01-01

CP47 is one of the two core antenna proteins of Photosystem II involved in the transfer of solar energy toward the photochemically active reaction center, the D1D2cytb559 complex. We have performed vis/vis and vis/mid-IR pump-probe experiments at room temperature as a first step in linking the

Measuring Fractional Anisotropy of the Corpus Callosum Using Diffusion Tensor Imaging: Mid-Sagittal versus Axial Imaging Planes

International Nuclear Information System (INIS)

Kim, Eung Yeop; Park, Hae Jeong; Kim, Dong Hyun; Lee, Seung Koo; Kim, Jin Na

2008-01-01

Many diffusion tensor imaging (DTI) studies of the corpus callosum (CC) have been performed with a relatively thick slice thickness in the axial plane, which may result in underestimating the fractional anisotropy (FA) of the CC due to a partial volume effect. We hypothesized that the FA of the CC can be more accurately measured by using mid-sagittal DTI. We compared the FA values of the CC between the axial and mid-sagittal DTI. Fourteen healthy volunteers underwent MRI at 3.0 T. DTI was performed in both the mid-sagittal and axial planes. One 5-mm mid-sagittal image and twenty-five 2-mm axial images were obtained for the CC. The five regions of interest (ROIs) that included the prefrontal (I), premotor and supplementary motor (II), motor (III), sensory (IV) and parietal, temporal and occipital regions (V) were drawn along the border of the CC on each sagittal FA map. The FA values obtained from each region were compared between the two sagittal maps. The FA values of all the regions, except for region V, were significantly increased on the mid-sagittal imaging. The FA values in region IV were significantly underestimated on the mid-sagittal image from the axial imaging, compared with those in the regions I and V (p = 0.037 and p = 0.001, respectively). The FA values of the CC were significantly higher on the midsagittal DTI than those on the axial DTI in regions I-IV, and particularly in the region IV. Mid-sagittal DTI may provide more accurate FA values of the CC than can the axial DTI, and mid-sagittal DTI may be more desirable for studies that compare between patients and healthy subjects

Research into the usage of integrated jamming of IR weakening and smoke-screen resisting the IR imaging guided missiles

Science.gov (United States)

Wang, Long-tao; Jiang, Ning; Lv, Ming-shan

2015-10-01

With the emergence of the anti-ship missle with the capability of infrared imaging guidance, the traditional single jamming measures, because of the jamming mechanism and technical flaws or unsuitable use, greatly reduced the survival probability of the war-ship in the future naval battle. Intergrated jamming of IR weakening + smoke-screen Can not only make jamming to the search and tracking of IR imaging guidance system , but also has feasibility in conjunction, besides , which also make the best jamming effect. The research conclusion has important realistic meaning for raising the antimissile ability of surface ships. With the development of guidance technology, infrared guidance system has expanded by ir point-source homing guidance to infrared imaging guidance, Infrared imaging guidance has made breakthrough progress, Infrared imaging guidance system can use two-dimensional infrared image information of the target, achieve the precise tracking. Which has Higher guidance precision, better concealment, stronger anti-interference ability and could Target the key parts. The traditional single infrared smoke screen jamming or infrared decoy flare interference cannot be imposed effective interference. So, Research how to effectively fight against infrared imaging guided weapons threat measures and means, improving the surface ship antimissile ability is an urgent need to solve.

Fluorenyl benzothiadiazole and benzoselenadiazole near-IR fluorescent probes for two-photon fluorescence imaging (Conference Presentation)

Science.gov (United States)

Belfield, Kevin D.; Yao, Sheng; Kim, Bosung; Yue, Xiling

2016-03-01

Imaging biological samples with two-photon fluorescence (2PF) microscopy has the unique advantage of resulting high contrast 3D resolution subcellular image that can reach up to several millimeters depth. 2PF probes that absorb and emit at near IR region need to be developed. Two-photon excitation (2PE) wavelengths are less concerned as 2PE uses wavelengths doubles the absorption wavelength of the probe, which means 2PE wavelengths for probes even with absorption at visible wavelength will fall into NIR region. Therefore, probes that fluoresce at near IR region with high quantum yields are needed. A series of dyes based on 5-thienyl-2, 1, 3-benzothiadiazole and 5-thienyl-2, 1, 3-benzoselenadiazole core were synthesized as near infrared two-photon fluorophores. Fluorescence maxima wavelengths as long as 714 nm and fluorescence quantum yields as high as 0.67 were achieved. The fluorescence quantum yields of the dyes were nearly constant, regardless of solvents polarity. These diazoles exhibited large Stokes shift (GM), and high two-photon fluorescence figure of merit (FM , 1.04×10-2 GM). Cells incubated on a 3D scaffold with one of the new probes (encapsulated in Pluronic micelles) exhibited bright fluorescence, enabling 3D two-photon fluorescence imaging to a depth of 100 µm.

Interference-free mid-IR laser absorption detection of methane

International Nuclear Information System (INIS)

Pyun, Sung Hyun; Cho, Jungwan; Davidson, David F; Hanson, Ronald K

2011-01-01

A novel, mid-IR scanned-wavelength laser absorption diagnostic was developed for time-resolved, interference-free, absorption measurement of methane concentration. A differential absorption (peak minus valley) scheme was used that takes advantage of the structural differences of the absorption spectrum of methane and other hydrocarbons. A peak and valley wavelength pair was selected to maximize the differential cross-section (σ peak minus valley ) of methane for the maximum signal-to-noise ratio, and to minimize that of the interfering absorbers. Methane cross-sections at the peak and valley wavelengths were measured over a range of temperatures, 1000 to 2000 K, and pressures 1.3 to 5.4 atm. The cross-sections of the interfering absorbers were assumed constant over the small wavelength interval between the methane peak and valley features. Using this diagnostic, methane concentration time histories during n-heptane pyrolysis were measured behind reflected shock waves in a shock tube. The differential absorption scheme efficiently rejected the absorption interference and successfully recovered the vapor-phase methane concentration. These measurements allowed the comparison with methane concentration time-history simulations derived from a current n-heptane reaction mechanism (Sirjean et al 2009 A high-temperature chemical kinetic model of n-alkane oxidation JetSurF version 1.0)

Content-Based High-Resolution Remote Sensing Image Retrieval via Unsupervised Feature Learning and Collaborative Affinity Metric Fusion

Directory of Open Access Journals (Sweden)

Yansheng Li

2016-08-01

Full Text Available With the urgent demand for automatic management of large numbers of high-resolution remote sensing images, content-based high-resolution remote sensing image retrieval (CB-HRRS-IR has attracted much research interest. Accordingly, this paper proposes a novel high-resolution remote sensing image retrieval approach via multiple feature representation and collaborative affinity metric fusion (IRMFRCAMF. In IRMFRCAMF, we design four unsupervised convolutional neural networks with different layers to generate four types of unsupervised features from the fine level to the coarse level. In addition to these four types of unsupervised features, we also implement four traditional feature descriptors, including local binary pattern (LBP, gray level co-occurrence (GLCM, maximal response 8 (MR8, and scale-invariant feature transform (SIFT. In order to fully incorporate the complementary information among multiple features of one image and the mutual information across auxiliary images in the image dataset, this paper advocates collaborative affinity metric fusion to measure the similarity between images. The performance evaluation of high-resolution remote sensing image retrieval is implemented on two public datasets, the UC Merced (UCM dataset and the Wuhan University (WH dataset. Large numbers of experiments show that our proposed IRMFRCAMF can significantly outperform the state-of-the-art approaches.

High resolution imaging detectors and applications

CERN Document Server

Saha, Swapan K

2015-01-01

Interferometric observations need snapshots of very high time resolution of the order of (i) frame integration of about 100 Hz or (ii) photon-recording rates of several megahertz (MHz). Detectors play a key role in astronomical observations, and since the explanation of the photoelectric effect by Albert Einstein, the technology has evolved rather fast. The present-day technology has made it possible to develop large-format complementary metal oxide–semiconductor (CMOS) and charge-coupled device (CCD) array mosaics, orthogonal transfer CCDs, electron-multiplication CCDs, electron-avalanche photodiode arrays, and quantum-well infrared (IR) photon detectors. The requirements to develop artifact-free photon shot noise-limited images are higher sensitivity and quantum efficiency, reduced noise that includes dark current, read-out and amplifier noise, smaller point-spread functions, and higher spectral bandwidth. This book aims to address such systems, technologies and design, evaluation and calibration, control...

Spitzer/infrared spectrograph investigation of mipsgal 24 μm compact bubbles: low-resolution observations

Energy Technology Data Exchange (ETDEWEB)

Nowak, M. [Département de Physique, École Normale Supérieure de Cachan, 61 Avenue du Président Wilson, F-94235 Cachan (France); Flagey, N. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Noriega-Crespo, A.; Carey, S. J.; Van Dyk, S. D. [Spitzer Science Center, California Institute of Technology, 1200 East California Boulevard, MC 314-6, Pasadena, CA 91125 (United States); Billot, N. [Instituto de Radio Astronomía Milimétrica, Avenida Divina Pastora, 7, Local 20, E-18012 Granada (Spain); Paladini, R., E-mail: mathias.nowak@ens-cachan.fr [NASA Herschel Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

2014-12-01

We present Spitzer/InfraRed Spectrograph (IRS) low-resolution observations of 11 compact circumstellar bubbles from the MIPSGAL 24 μm Galactic plane survey. We find that this set of MIPSGAL bubbles (MBs) is divided into two categories and that this distinction correlates with the morphologies of the MBs in the mid-infrared (IR). The four MBs with central sources in the mid-IR exhibit dust-rich, low-excitation spectra, and their 24 μm emission is accounted for by the dust continuum. The seven MBs without central sources in the mid-IR have spectra dominated by high-excitation gas lines (e.g., [O IV] 26.0 μm, [Ne V] 14.3 and 24.3 μm, and [Ne III] 15.5 μm), and the [O IV] line accounts for 50% to almost 100% of the 24 μm emission in five of them. In the dust-poor MBs, the [Ne V] and [Ne III] line ratios correspond to high-excitation conditions. Based on comparisons with published IRS spectra, we suggest that the dust-poor MBs are highly excited planetary nebulae (PNs) with peculiar white dwarfs (e.g., Wolf-Rayet [WR] and novae) at their centers. The central stars of the four dust-rich MBs are all massive star candidates. Dust temperatures range from 40 to 100 K in the outer shells. We constrain the extinction along the lines of sight from the IRS spectra. We then derive distance, dust masses, and dust production rate estimates for these objects. These estimates are all consistent with the nature of the central stars. We summarize the identifications of MBs made to date and discuss the correlation between their mid-IR morphologies and natures. Candidate Be/B[e]/luminous blue variable and WR stars are mainly 'rings' with mid-IR central sources, whereas PNs are mostly 'disks' without mid-IR central sources. Therefore we expect that most of the 300 remaining unidentified MBs will be classified as PNs.

High-power, continuous-wave, mid-infrared optical parametric oscillator based on MgO:sPPLT.

Science.gov (United States)

Chaitanya Kumar, S; Ebrahim-Zadeh, M

2011-07-01

We report a stable, high-power, cw, mid-IR optical parametric oscillator using MgO-doped stoichiometric periodically poled LiTaO₃ (MgO:sPPLT) pumped by a Yb fiber laser at 1064 nm. The singly resonant oscillator (SRO), based on a 30 mm long crystal, is tunable over 430 nm from 3032 to 3462 nm and can generate as much as 5.5 W of mid-IR output power, with >4 W of over 60% of the tuning range and under reduced thermal effects, enabling room temperature operation. Idler power scaling measurements at ~3.3 μm are compared with an MgO-doped periodically poled LiNbO₃ cw SRO, confirming that MgO:sPPLT is an attractive material for multiwatt mid-IR generation. The idler output at 3299 nm exhibits a peak-to-peak power stability better than 12.8% over 5 h and frequency stability of ~1 GHz, while operating close to room temperature, and has a linewidth of ~0.2 nm, limited by the resolution of the wavemeter. The corresponding signal linewidth at 1570 nm is ~21 MHz.

The importance of resolution on the response of mid-latitude transients to enhanced CO2

International Nuclear Information System (INIS)

Senior, C.A.

1994-01-01

The impact of global warming on the activity of the mid-latitude transients is not well understood. Work with simple models suggests that there will be two competing effects on transient activity. Firstly, there will be a reduction in the baroclinicity due to a smaller pole-equator temperature gradient and secondly there will be increased moisture availability in a warmer atmosphere. A comparison of the mid-latitude transients from two versions of the Hadley Centre for Climate Prediction and Research GCM run at different resolutions is presented and the importance of resolution on the simulation of the high and low frequency variability is discussed. At higher resolution, one of the largest responses of the model to a doubling of atmospheric CO 2 is an enhancement of the westerly flow in the North Atlantic, but this is much reduced at lower resolution. Consistency is sort between changes in the time mean flow and the transient behavior

Performance Evaluation of Three Different High Resolution Satellite Images in Semi-Automatic Urban Illegal Building Detection

Science.gov (United States)

Khalilimoghadama, N.; Delavar, M. R.; Hanachi, P.

2017-09-01

The problem of overcrowding of mega cities has been bolded in recent years. To meet the need of housing this increased population, which is of great importance in mega cities, a huge number of buildings are constructed annually. With the ever-increasing trend of building constructions, we are faced with the growing trend of building infractions and illegal buildings (IBs). Acquiring multi-temporal satellite images and using change detection techniques is one of the proper methods of IB monitoring. Using the type of satellite images with different spatial and spectral resolutions has always been an issue in efficient detection of the building changes. In this research, three bi-temporal high-resolution satellite images of IRS-P5, GeoEye-1 and QuickBird sensors acquired from the west of metropolitan area of Tehran, capital of Iran, in addition to city maps and municipality property database were used to detect the under construction buildings with improved performance and accuracy. Furthermore, determining the employed bi-temporal satellite images to provide better performance and accuracy in the case of IB detection is the other purpose of this research. The Kappa coefficients of 70 %, 64 %, and 68 % were obtained for producing change image maps using GeoEye-1, IRS-P5, and QuickBird satellite images, respectively. In addition, the overall accuracies of 100 %, 6 %, and 83 % were achieved for IB detection using the satellite images, respectively. These accuracies substantiate the fact that the GeoEye-1 satellite images had the best performance among the employed images in producing change image map and detecting the IBs.

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

OpenAIRE

Kotasidis Fotis A.; Kotasidis Fotis A.; Angelis Georgios I.; Anton-Rodriguez Jose; Matthews Julian C.; Reader Andrew J.; Reader Andrew J.; Zaidi Habib; Zaidi Habib; Zaidi Habib

2014-01-01

Purpose: Measuring and incorporating a scanner specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However due to the short half life of clinically used isotopes other long lived isotopes not used in clinical practice are used to perform the PSF measurements. As such non optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction usuall...

Image Fusion-Based Land Cover Change Detection Using Multi-Temporal High-Resolution Satellite Images

Directory of Open Access Journals (Sweden)

Biao Wang

2017-08-01

Full Text Available Change detection is usually treated as a problem of explicitly detecting land cover transitions in satellite images obtained at different times, and helps with emergency response and government management. This study presents an unsupervised change detection method based on the image fusion of multi-temporal images. The main objective of this study is to improve the accuracy of unsupervised change detection from high-resolution multi-temporal images. Our method effectively reduces change detection errors, since spatial displacement and spectral differences between multi-temporal images are evaluated. To this end, a total of four cross-fused images are generated with multi-temporal images, and the iteratively reweighted multivariate alteration detection (IR-MAD method—a measure for the spectral distortion of change information—is applied to the fused images. In this experiment, the land cover change maps were extracted using multi-temporal IKONOS-2, WorldView-3, and GF-1 satellite images. The effectiveness of the proposed method compared with other unsupervised change detection methods is demonstrated through experimentation. The proposed method achieved an overall accuracy of 80.51% and 97.87% for cases 1 and 2, respectively. Moreover, the proposed method performed better when differentiating the water area from the vegetation area compared to the existing change detection methods. Although the water area beneath moderate and sparse vegetation canopy was captured, vegetation cover and paved regions of the water body were the main sources of omission error, and commission errors occurred primarily in pixels of mixed land use and along the water body edge. Nevertheless, the proposed method, in conjunction with high-resolution satellite imagery, offers a robust and flexible approach to land cover change mapping that requires no ancillary data for rapid implementation.

High resolution spectroscopic mapping imaging applied in situ to multilayer structures for stratigraphic identification of painted art objects

Science.gov (United States)

Karagiannis, Georgios Th.

2016-04-01

The development of non-destructive techniques is a reality in the field of conservation science. These techniques are usually not so accurate, as the analytical micro-sampling techniques, however, the proper development of soft-computing techniques can improve their accuracy. In this work, we propose a real-time fast acquisition spectroscopic mapping imaging system that operates from the ultraviolet to mid infrared (UV/Vis/nIR/mIR) area of the electromagnetic spectrum and it is supported by a set of soft-computing methods to identify the materials that exist in a stratigraphic structure of paint layers. Particularly, the system acquires spectra in diffuse-reflectance mode, scanning in a Region-Of-Interest (ROI), and having wavelength range from 200 up to 5000 nm. Also, a fuzzy c-means clustering algorithm, i.e., the particular soft-computing algorithm, produces the mapping images. The evaluation of the method was tested on a byzantine painted icon.

Mid-infrared integrated photonics on silicon: a perspective

Directory of Open Access Journals (Sweden)

Lin Hongtao

2017-12-01

Full Text Available The emergence of silicon photonics over the past two decades has established silicon as a preferred substrate platform for photonic integration. While most silicon-based photonic components have so far been realized in the near-infrared (near-IR telecommunication bands, the mid-infrared (mid-IR, 2–20-μm wavelength band presents a significant growth opportunity for integrated photonics. In this review, we offer our perspective on the burgeoning field of mid-IR integrated photonics on silicon. A comprehensive survey on the state-of-the-art of key photonic devices such as waveguides, light sources, modulators, and detectors is presented. Furthermore, on-chip spectroscopic chemical sensing is quantitatively analyzed as an example of mid-IR photonic system integration based on these basic building blocks, and the constituent component choices are discussed and contrasted in the context of system performance and integration technologies.

Optimal image resolution for digital storage of radiotherapy-planning images

International Nuclear Information System (INIS)

Baba, Yuji; Furusawa, Mitsuhiro; Murakami, Ryuji; Baba, Takashi; Yokoyama, Toshimi; Nishimura, Ryuichi; Takahashi, Mutsumasa

1998-01-01

Purpose: To evaluate the quality of digitized radiation-planning images at different resolution and to determine the optimal resolution for digital storage. Methods and Materials: Twenty-five planning films were scanned and digitized using a film scanner at a resolution of 72 dots per inch (dpi) with 8-bit depth. The resolution of scanned images was reduced to 48, 36, 24, and 18 dpi using computer software. Image qualities of these five images (72, 48, 36, 24, and 18 dpi) were evaluated and given scores (4 = excellent; 3 = good; 2 = fair; and 1 = poor) by three radiation oncologists. An image data compression algorithm by the Joint Photographic Experts Group (JPEG) (not reversible and some information will be lost) was also evaluated. Results: The scores of digitized images with 72, 48, 36, 24, and 17 dpi resolution were 3.8 ± 0.3, 3.5 ± 0.3, 3.3 ± 0.5, 2.7 ± 0.5, and 1.6 ± 0.3, respectively. The quality of 36-dpi images were definitely worse compared to 72-dpi images, but were good enough as planning films. Digitized planning images with 72- and 36-dpi resolution requires about 800 and 200 KBytes, respectively. The JPEG compression algorithm produces little degradation in 36-dpi images at compression ratios of 5:1. Conclusion: The quality of digitized images with 36-dpi resolution was good enough as radiation-planning images and required 200 KBytes/image

Mid-IR Spectra of Refractory Minerals Relevant to Comets

Science.gov (United States)

Jauhari, Shekeab

2008-09-01

On 4 July 2005 the Spitzer Space Telescope obtained mid-IR ( 5-40 µm) spectra of the ejecta from the hypervelocity impact of the Deep Impact projectile with comet 9P/Tempel 1. Spectral modeling demonstrates that there are abundant minerals present in the ejecta including Ca/Fe/Mg-rich silicates, carbonates, phyllosilicates, water ice, amorphous carbon, and sulfides [1]. However, precise mineralogical identifications are hampered by the lack of comprehensive 5 - 40 µm spectral measurements of the emissivity for a broad compositional range of these materials. Here, we present our initial results for 2 - 50 µm transmission spectra and absorption constants for materials relevant to comets, including pyrrhotite, pyrite, and several phyllosilicate (clay) minerals. Measuring the transmission of materials over the full spectral range sensitive by Spitzer requires grinding the minerals into submicron powders and then mixing them with KBr (for the 1-25 um region) and polyethylene (16-50 um region) to form pellets. Transmission measurements of sub-micron sulfides are particularly difficult to obtain because the minerals oxidize rapidly upon grinding and subsequent handling unless special care is taken. A detailed description of our sample preparation and measurement technique will be provided to assist other researchers in their attempts to acquire similar spectra. References: [1] Lisse, C.M. et al., Science 313, 635 - 640 (2006)

NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Mid Shelf Reef (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the Mid Shelf Reef south of St. Thomas, US Virgin IslandsNOAA's NOS/NCCOS/CCMA Biogeography Team,...

On-line monitoring of methanol and methyl formate in the exhaust gas of an industrial formaldehyde production plant by a mid-IR gas sensor based on tunable Fabry-Pérot filter technology.

Science.gov (United States)

Genner, Andreas; Gasser, Christoph; Moser, Harald; Ofner, Johannes; Schreiber, Josef; Lendl, Bernhard

2017-01-01

On-line monitoring of key chemicals in an industrial production plant ensures economic operation, guarantees the desired product quality, and provides additional in-depth information on the involved chemical processes. For that purpose, rapid, rugged, and flexible measurement systems at reasonable cost are required. Here, we present the application of a flexible mid-IR filtometer for industrial gas sensing. The developed prototype consists of a modulated thermal infrared source, a temperature-controlled gas cell for absorption measurement and an integrated device consisting of a Fabry-Pérot interferometer and a pyroelectric mid-IR detector. The prototype was calibrated in the research laboratory at TU Wien for measuring methanol and methyl formate in the concentration ranges from 660 to 4390 and 747 to 4610 ppmV. Subsequently, the prototype was transferred and installed at the project partner Metadynea Austria GmbH and linked to their Process Control System via a dedicated micro-controller and used for on-line monitoring of the process off-gas. Up to five process streams were sequentially monitored in a fully automated manner. The obtained readings for methanol and methyl formate concentrations provided useful information on the efficiency and correct functioning of the process plant. Of special interest for industry is the now added capability to monitor the start-up phase and process irregularities with high time resolution (5 s).

Achromatic wave plates for the mid-infrared

Science.gov (United States)

Beasley, J. Donald; Marlowe, Philip D.

2012-06-01

Achromatic wave plates are useful in various mid-IR applications, such as analyzing or controlling the spectrum available from CO2 and other lasers, and for the study of IR spectra from distant stars. Their production relies upon the technical skills of those who grow the required high quality crystals and upon those who fabricate the optical parts to the needed precision. Two materials are described - one useful for light in the spectral range of the visible through the near IR and another that functions well in mid-IR applications from 2.5 μm to 11.5 μm. Some limitations imposed by inherent material properties will also be discussed.

Looking at Art in the IR and UV

Science.gov (United States)

Falco, Charles

2013-03-01

Starting with the very earliest cave paintings art has been created to be viewed by the unaided eye and, until very recently, it wasn't even possible to see it at wavelengths outside the visible spectrum. However, it is now possible to view paintings, sculptures, manuscripts, and other cultural artifacts at wavelengths from the x-ray, through the ultraviolet (UV), to well into the infrared (IR). Further, thanks to recent advances in technology, this is becoming possible with hand-held instruments that can be used in locations that were previously inaccessible to anything but laboratory-scale image capture equipment. But, what can be learned from such ``non-visible'' images? In this talk I will briefly describe the characteristics of high resolution UV and IR imaging systems I developed for this purpose by modifying high resolution digital cameras. The sensitivity of the IR camera makes it possible to obtain images of art ``in situ'' with standard museum lighting, resolving features finer than 0.35 mm on a 1.0x0.67 m painting. I also have used both it and the UV camera in remote locations with battery-powered illumination sources. I will illustrate their capabilities with images of various examples of Western, Asian, and Islamic art in museums on three continents, describing how these images have revealed important new information about the working practices of artists as famous as Jan van Eyck. I also will describe what will be possible for this type of work with new capabilities that could be developed within the next few years. This work is based on a collaboration with David Hockney, and benefitted from image analys research supported by ARO grant W911NF-06-1-0359-P00001.

Super-resolution for everybody: An image processing workflow to obtain high-resolution images with a standard confocal microscope.

Science.gov (United States)

Lam, France; Cladière, Damien; Guillaume, Cyndélia; Wassmann, Katja; Bolte, Susanne

2017-02-15

In the presented work we aimed at improving confocal imaging to obtain highest possible resolution in thick biological samples, such as the mouse oocyte. We therefore developed an image processing workflow that allows improving the lateral and axial resolution of a standard confocal microscope. Our workflow comprises refractive index matching, the optimization of microscope hardware parameters and image restoration by deconvolution. We compare two different deconvolution algorithms, evaluate the necessity of denoising and establish the optimal image restoration procedure. We validate our workflow by imaging sub resolution fluorescent beads and measuring the maximum lateral and axial resolution of the confocal system. Subsequently, we apply the parameters to the imaging and data restoration of fluorescently labelled meiotic spindles of mouse oocytes. We measure a resolution increase of approximately 2-fold in the lateral and 3-fold in the axial direction throughout a depth of 60μm. This demonstrates that with our optimized workflow we reach a resolution that is comparable to 3D-SIM-imaging, but with better depth penetration for confocal images of beads and the biological sample. Copyright © 2016 Elsevier Inc. All rights reserved.

Fourier Transform Near Infrared Microspectroscopy, Infrared Chemical Imaging, High-Resolution Nuclear Magnetic Resonance and Fluorescence Microspectroscopy Detection of Single Cancer Cells and Single Viral Particles

CERN Document Server

Baianu,I C; Hofmann, N E; Korban, S S; Lozano, P; You, T

2004-01-01

Single Cancer Cells from Human tumors are being detected and imaged by Fourier Transform Infrared (FT-IR), Fourier Transform Near Infrared (FT-NIR)Hyperspectral Imaging and Fluorescence Correlation Microspectroscopy. The first FT-NIR chemical, microscopic images of biological systems approaching one micron resolution are here reported. Chemical images obtained by FT-NIR and FT-IR Microspectroscopy are also presented for oil in soybean seeds and somatic embryos under physiological conditions. FT-NIR spectra of oil and proteins were obtained for volumes as small as two cubic microns. Related, HR-NMR analyses of oil contents in somatic embryos as well as 99% accurate calibrations are also presented here with nanoliter precision. Such high-resolution, 400 MHz H-1 NMR analyses allowed the selection of mutagenized embryos with higher oil content (e.g. >~20%) compared to the average levels in non-mutagenized control embryos. Moreover, developmental changes in single soybean seeds and/or somatic embryos may be monito...

Observation of an octave-spanning supercontinuum in the mid-infrared using ultrafast cascaded nonlinearities

DEFF Research Database (Denmark)

Bache, Morten; Liu, Xing; Zhou, Binbin

2014-01-01

An octave-spanning mid-IR supercontinuum is observed experimentally using ultrafast cascaded nonlinearities in an LiInS2 quadratic nonlinear crystal pumped with 70 fs energetic mid-IR pulses and cut for strongly phase-mismatched second-harmonic generation. ©OSA 2014.......An octave-spanning mid-IR supercontinuum is observed experimentally using ultrafast cascaded nonlinearities in an LiInS2 quadratic nonlinear crystal pumped with 70 fs energetic mid-IR pulses and cut for strongly phase-mismatched second-harmonic generation. ©OSA 2014....

Femtosecond few-cycle mid-infrared laser pulses

DEFF Research Database (Denmark)

Liu, Xing

The few-cycle pulses of mid-infrared (mid-IR, wavelength 2-10 microns) have attracted increasing attention owing to their great potentials for high order harmonic generation, time-resolved spectroscopy, precision of cutting and biomedical science.In this thesis, mid-IR frequency conversion.......2 - 5.5 μm with only one fixed pump wavelength, a feature absent in Kerr media. Finally, we experimentally observe supercontinuum generation spanning 1.5 octaves, generated in a 10 mm long silicon-rich nitride waveguide pumped by 100 pJ femtosecond pulses from an erbium fiber laser. The waveguide has...

Application of Super-Resolution Convolutional Neural Network for Enhancing Image Resolution in Chest CT.

Science.gov (United States)

Umehara, Kensuke; Ota, Junko; Ishida, Takayuki

2017-10-18

In this study, the super-resolution convolutional neural network (SRCNN) scheme, which is the emerging deep-learning-based super-resolution method for enhancing image resolution in chest CT images, was applied and evaluated using the post-processing approach. For evaluation, 89 chest CT cases were sampled from The Cancer Imaging Archive. The 89 CT cases were divided randomly into 45 training cases and 44 external test cases. The SRCNN was trained using the training dataset. With the trained SRCNN, a high-resolution image was reconstructed from a low-resolution image, which was down-sampled from an original test image. For quantitative evaluation, two image quality metrics were measured and compared to those of the conventional linear interpolation methods. The image restoration quality of the SRCNN scheme was significantly higher than that of the linear interpolation methods (p < 0.001 or p < 0.05). The high-resolution image reconstructed by the SRCNN scheme was highly restored and comparable to the original reference image, in particular, for a ×2 magnification. These results indicate that the SRCNN scheme significantly outperforms the linear interpolation methods for enhancing image resolution in chest CT images. The results also suggest that SRCNN may become a potential solution for generating high-resolution CT images from standard CT images.

A spatial study of the mid-IR emission features in four Herbig Ae/Be stars

NARCIS (Netherlands)

Boersma, C.; Peeters, E.; Martin-Hernandez, N. L.; van der Wolk, G.; Verhoeff, A. P.; Tielens, A. G. G. M.; Waters, L. B. F. M.; Pel, J. W.

Context. Infrared (IR) spectroscopy and imaging provide a prime tool to study the characteristics of polycyclic aromatic hydrocarbon (PAH) molecules and the mineralogy in regions of star formation. Herbig Ae/Be stars are known to have varying amounts of natal cloud material present in their

Highly doped InP as a low loss plasmonic material for mid-IR region

DEFF Research Database (Denmark)

Panah, Mohammad Esmail Aryaee; Takayama, Osamu; Morozov, S. V.

2016-01-01

by fitting the calculated infrared reflectance spectra to the measured ones. The retrieved permittivity was then used to simulate surface plasmon polaritons (SPPs) propagation on flat and structured surfaces, and the simulation results were verified in direct experiments. SPPs at the top and bottom......We study plasmonic properties of highly doped InP in the mid-infrared (IR) range. InP was grown by metal-organic vapor phase epitaxy (MOVPE) with the growth conditions optimized to achieve high free electron concentrations by doping with silicon. The permittivity of the grown material was found...... interfaces of the grown epilayer were excited by the prism coupling. A high-index Ge hemispherical prism provides efficient coupling conditions of SPPs on flat surfaces and facilitates acquiring their dispersion diagrams. We observed diffraction into symmetry-prohibited diffraction orders stimulated...

Design of high-efficiency diffractive optical elements towards ultrafast mid-infrared time-stretched imaging and spectroscopy

Science.gov (United States)

Xie, Hongbo; Ren, Delun; Wang, Chao; Mao, Chensheng; Yang, Lei

2018-02-01

Ultrafast time stretch imaging offers unprecedented imaging speed and enables new discoveries in scientific research and engineering. One challenge in exploiting time stretch imaging in mid-infrared is the lack of high-quality diffractive optical elements (DOEs), which encode the image information into mid-infrared optical spectrum. This work reports the design and optimization of mid-infrared DOE with high diffraction-efficiency, broad bandwidth and large field of view. Using various typical materials with their refractive indices ranging from 1.32 to 4.06 in ? mid-infrared band, diffraction efficiencies of single-layer and double-layer DOEs have been studied in different wavelength bands with different field of views. More importantly, by replacing the air gap of double-layer DOE with carefully selected optical materials, one optimized ? triple-layer DOE, with efficiency higher than 95% in the whole ? mid-infrared window and field of view greater than ?, is designed and analyzed. This new DOE device holds great potential in ultrafast mid-infrared time stretch imaging and spectroscopy.

The nature of the Galactic Center source IRS 13 revealed by high spatial resolution in the infrared

Science.gov (United States)

Maillard, J. P.; Paumard, T.; Stolovy, S. R.; Rigaut, F.

2004-08-01

High spatial resolution observations in the 1 to 3.5 μm/ region of the Galactic Center source known historically as IRS 13 are presented. They include ground-based adaptive optics images in the H, Kp (2.12/0.4 μm) and L bands, HST-NICMOS data in filters between 1.1 and 2.2 μm, and integral field spectroscopic data from BEAR, an Imaging FTS, in the He I 2.06 μm/ and the Brγ line regions. Analysis of all these data provides a completely new picture of the main component, IRS 13E, which appears as a cluster of seven individual stars within a projected diameter of ˜0.5 arcsec (0.02 pc). The brightest sources, 13E1, 13E2, 13E3 which is detected as a binary, and 13E4, are all massive stars of different type. The star 13E1 is a luminous, blue object, with no detected emission line. 13E2 and 13E4 are two hot, high-mass emission line stars, 13E2 being at the WR stage and 13E4 a massive O-type star. In contrast, 13E3A and B are extremely red objects, proposed as other examples of dusty WR stars, like IRS 21 (Tanner et al. \\cite{tanner}). All these sources have a common westward proper motion (Ott et al. \\cite{ott2}) indicating they are bounded. Two other sources, detected after deconvolution of the AO images in the H and Kp bands, are also identified. One, that we call 13E5, is a red source similar to 13E3A and B, while the other one, 13E6, is probably a main sequence O star in front of the cluster. Considering this exceptional concentration of comoving massive hot stars, IRS 13E is proposed as the remaining core of a massive star cluster, which could harbor an intermediate-mass black hole (IMBH) (Portegies Zwart & McMillan \\cite{zwart2)} of ˜1300 M⊙. This detection plays in favor of a scenario, first suggested by Gerhard (\\cite{gerhard}), in which the helium stars and the other hot stars in the central parsec originate from the stripping of a massive cluster formed several tens of pc from the center. This cluster would have spiraled towards SgrA*, and IRS 13E

Resolution enhancement in medical ultrasound imaging.

Science.gov (United States)

Ploquin, Marie; Basarab, Adrian; Kouamé, Denis

2015-01-01

Image resolution enhancement is a problem of considerable interest in all medical imaging modalities. Unlike general purpose imaging or video processing, for a very long time, medical image resolution enhancement has been based on optimization of the imaging devices. Although some recent works purport to deal with image postprocessing, much remains to be done regarding medical image enhancement via postprocessing, especially in ultrasound imaging. We face a resolution improvement issue in the case of medical ultrasound imaging. We propose to investigate this problem using multidimensional autoregressive (AR) models. Noting that the estimation of the envelope of an ultrasound radio frequency (RF) signal is very similar to the estimation of classical Fourier-based power spectrum estimation, we theoretically show that a domain change and a multidimensional AR model can be used to achieve super-resolution in ultrasound imaging provided the order is estimated correctly. Here, this is done by means of a technique that simultaneously estimates the order and the parameters of a multidimensional model using relevant regression matrix factorization. Doing so, the proposed method specifically fits ultrasound imaging and provides an estimated envelope. Moreover, an expression that links the theoretical image resolution to both the image acquisition features (such as the point spread function) and a postprocessing feature (the AR model) order is derived. The overall contribution of this work is threefold. First, it allows for automatic resolution improvement. Through a simple model and without any specific manual algorithmic parameter tuning, as is used in common methods, the proposed technique simply and exclusively uses the ultrasound RF signal as input and provides the improved B-mode as output. Second, it allows for the a priori prediction of the improvement in resolution via the knowledge of the parametric model order before actual processing. Finally, to achieve the

FT-midIR determination of fatty acid profiles, including trans fatty acids, in bakery products after focused microwave-assisted Soxhlet extraction.

Science.gov (United States)

Ruiz-Jiménez, J; Priego-Capote, F; Luque de Castro, M D

2006-08-01

A study of the feasibility of Fourier transform medium infrared spectroscopy (FT-midIR) for analytical determination of fatty acid profiles, including trans fatty acids, is presented. The training and validation sets-75% (102 samples) and 25% (36 samples) of the samples once the spectral outliers have been removed-to develop FT-midIR general equations, were built with samples from 140 commercial and home-made bakery products. The concentration of the analytes in the samples used for this study is within the typical range found in these kinds of products. Both sets were independent; thus, the validation set was only used for testing the equations. The criterion used for the selection of the validation set was samples with the highest number of neighbours and the most separation between them (H/=0.90, SEP=1-1.5 SEL and R (2)=0.70-0.89, SEP=2-3 SEL, respectively. The results obtained with the proposed method were compared with those provided by the conventional method based on GC-MS. At 95% significance level, the differences between the values obtained for the different fatty acids were within the experimental error.

Tunable optical coherence tomography in the infrared range using visible photons

Science.gov (United States)

Paterova, Anna V.; Yang, Hongzhi; An, Chengwu; Kalashnikov, Dmitry A.; Krivitsky, Leonid A.

2018-04-01

Optical coherence tomography (OCT) is an appealing technique for bio-imaging, medicine, and material analysis. For many applications, OCT in mid- and far-infrared (IR) leads to significantly more accurate results. Reported mid-IR OCT systems require light sources and photodetectors which operate in mid-IR range. These devices are expensive and need cryogenic cooling. Here, we report a proof-of-concept demonstration of a wavelength tunable IR OCT technique with detection of only visible range photons. Our method is based on the nonlinear interference of frequency correlated photon pairs. The nonlinear crystal, introduced in the Michelson-type interferometer, generates photon pairs with one photon in the visible and another in the IR range. The intensity of detected visible photons depends on the phase and loss of IR photons, which interact with the sample under study. This enables us to characterize sample properties and perform imaging in the IR range by detecting visible photons. The technique possesses broad wavelength tunability and yields a fair axial and lateral resolution, which can be tailored to the specific application. The work contributes to the development of versatile 3D imaging and material characterization systems working in a broad range of IR wavelengths, which do not require the use of IR-range light sources and photodetectors.

Applications of a Mid-IR Quantum Cascade Laser in Gas Sensing Research

KAUST Repository

Sajid, Muhammad Bilal

2015-05-01

Laser absorption based sensors are extensively used in a variety of gas sensing areas such as combustion, atmospheric research, human breath analysis, and high resolution infrared spectroscopy. Quantum cascade lasers have recently emerged as high resolution, high power laser sources operating in mid infrared region and can have wide tunability range. These devices provide an opportunity to access stronger fundamental and combination vibrational bands located in mid infrared region than previously accessible weaker overtone vibrational bands located in near infrared region. Spectroscopic region near 8 µm contains strong vibrational bands of methane, acetylene, hydrogen peroxide, water vapor and nitrous oxide. These molecules have important applications in a wide range of applications. This thesis presents studies pertaining to spectroscopy and combustion applications. Advancements in combustion research are imperative to achieve lower emissions and higher efficiency in practical combustion devices such as gas turbines and engines. Accurate chemical kinetic models are critical to achieve predictive models which contain several thousand reactions and hundreds of species. These models need highly reliable experimental data for validation and improvements. Shock tubes are ideal devices to obtain such information. A shock tube is a homogenous, nearly constant volume, constant pressure, adiabatic and 0-D reactor. In combination with laser absorption sensors, shock tubes can be used to measure reaction rates and species time histories of several intermediates and products formed during pyrolysis and oxidation of fuels. This work describes measurement of the decomposition rate of hydrogen peroxide which is an important intermediate species controlling reactivity of combustion system in the intermediate temperature range. Spectroscopic parameters (linestrengths, broadening coefficients and temperature dependent coefficients) are determined for various transitions of

Future development of IR thermovision weather satellite equipment

Science.gov (United States)

Listratov, A. V.

1974-01-01

The self radiation of the surface being viewed is used for image synthesis in IR thermovision equipment. The installation of such equipment aboard weather satellites makes it possible to obtain cloud cover pictures of the earth's surface in a complete orbit, regardless of the illumination conditions, and also provides quantitative information on the underlying surface temperature and cloud top height. Such equipment is used successfully aboard the Soviet satellites of the Meteor system, and experimentally on the American satellites of the Nimbus series. With regard to surface resolution, the present-day IR weather satellite equipment is inferior to the television equipment. This is due primarily to the comparatively low detectivity of the IR detectors used. While IR equipment has several fundamental advantages in comparison with the conventional television equipment, the problem arises of determining the possibility for future development of weather satellite IR thermovision equipment. Criteria are examined for evaluating the quality of IR.

Extending laser plasma accelerators into the mid-IR spectral domain with a next-generation ultra-fast CO2 laser

Science.gov (United States)

Pogorelsky, I. V.; Babzien, M.; Ben-Zvi, I.; Polyanskiy, M. N.; Skaritka, J.; Tresca, O.; Dover, N. P.; Najmudin, Z.; Lu, W.; Cook, N.; Ting, A.; Chen, Y.-H.

2016-03-01

Expanding the scope of relativistic plasma research to wavelengths longer than the λ/≈   0.8-1.1 μm range covered by conventional mode-locked solid-state lasers would offer attractive opportunities due to the quadratic scaling of the ponderomotive electron energy and critical plasma density with λ. Answering this quest, a next-generation mid-IR laser project is being advanced at the BNL ATF as a part of the user facility upgrade. We discuss the technical approach to this conceptually new 100 TW, 100 fs, λ  =   9-11 μm CO2 laser BESTIA (Brookhaven Experimental Supra-Terawatt Infrared at ATF) that encompasses several innovations applied for the first time to molecular gas lasers. BESTIA will enable new regimes of laser plasma accelerators. One example is shock-wave ion acceleration (SWA) from gas jets. We review ongoing efforts to achieve stable, monoenergetic proton acceleration by dynamically shaping the plasma density profile from a hydrogen gas target with laser-produced blast waves. At its full power, 100 TW BESTIA promises to achieve proton beams at an energy exceeding 200 MeV. In addition to ion acceleration in over-critical plasma, the ultra-intense mid-IR BESTIA will open up new opportunities in driving wakefields in tenuous plasmas, expanding the landscape of laser wakefield accelerator (LWFA) studies into the unexplored long-wavelength spectral domain. Simple wavelength scaling suggests that a 100 TW CO2 laser beam will be capable of efficiently generating plasma ‘bubbles’ a thousand times greater in volume compared with a near-IR solid state laser of an equivalent power. Combined with a femtosecond electron linac available at the ATF, this wavelength scaling will facilitate the study of external seeding and staging of LWFAs.

Gaseous effluent monitoring and identification using an imaging Fourier transform spectrometer

Energy Technology Data Exchange (ETDEWEB)

Carter, M.R.; Bennett, C.L.; Fields, D.J.; Hernandez, J.

1993-10-01

We are developing an imaging Fourier transform spectrometer for chemical effluent monitoring. The system consists of a 2-D infrared imaging array in the focal plane of a Michelson interferometer. Individual images are coordinated with the positioning of a moving mirror in the Michelson interferometer. A three dimensional data cube with two spatial dimensions and one interferogram dimension is then Fourier transformed to produce a hyperspectral data cube with one spectral dimension and two spatial dimensions. The spectral range of the instrument is determined by the choice of optical components and the spectral range of the focal plane array. Measurements in the near UV, visible, near IR, and mid-IR ranges are possible with the existing instrument. Gaseous effluent monitoring and identification measurements will be primarily in the ``fingerprint`` region of the spectrum, ({lambda} = 8 to 12 {mu}m). Initial measurements of effluent using this imaging interferometer in the mid-IR will be presented.

Photochemistry of Fe:H2O Adducts in Argon Matrixes: A Combined Experimental and Theoretical Study in the Mid-IR and UV-Visible Regions.

Science.gov (United States)

Deguin, Vincent; Mascetti, Joëlle; Simon, Aude; Ben Amor, Nadia; Aupetit, Christian; Latournerie, Sandra; Noble, Jennifer A

2018-01-18

The photochemistry of Fe:H 2 O adducts is of interest in fields as diverse as catalysis and astrochemistry. Industrially, iron can be used as a catalyst to convert H 2 O to H 2 , whereas in the interstellar medium it may be an important component of dust grains, influencing the chemistry on their icy surfaces. This study consisted of the deposition and spectral characterization of binary systems of atomic iron with H 2 O in cryogenic argon matrixes. In this way, we were able to obtain information about the interaction of the two species; we observed the formation of adducts of iron monomers and dimers with water molecules in the mid-IR and UV-visible spectral domains. Upon irradiation with a UV radiation source, the iron species were inserted into the water molecules to form HFeOH and HFe 2 OH, leading in some cases to the formation of FeO possibly accompanied by the production of H 2 . DFT and correlated multireference wave function calculations confirmed our attributions. This combination of IR and UV-visible spectroscopy with theoretical calculations allowed us to determine, for the first time, the spectral characteristics of iron adducts and their photoproducts in the UV-visible and in the OH stretching region of the mid-IR domain.

Change of spatial information under rescaling: A case study using multi-resolution image series

Science.gov (United States)

Chen, Weirong; Henebry, Geoffrey M.

Spatial structure in imagery depends on a complicated interaction between the observational regime and the types and arrangements of entities within the scene that the image portrays. Although block averaging of pixels has commonly been used to simulate coarser resolution imagery, relatively little attention has been focused on the effects of simple rescaling on spatial structure and the explanation and a possible solution to the problem. Yet, if there are significant differences in spatial variance between rescaled and observed images, it may affect the reliability of retrieved biogeophysical quantities. To investigate these issues, a nested series of high spatial resolution digital imagery was collected at a research site in eastern Nebraska in 2001. An airborne Kodak DCS420IR camera acquired imagery at three altitudes, yielding nominal spatial resolutions ranging from 0.187 m to 1 m. The red and near infrared (NIR) bands of the co-registered image series were normalized using pseudo-invariant features, and the normalized difference vegetation index (NDVI) was calculated. Plots of grain sorghum planted in orthogonal crop row orientations were extracted from the image series. The finest spatial resolution data were then rescaled by averaging blocks of pixels to produce a rescaled image series that closely matched the spatial resolution of the observed image series. Spatial structures of the observed and rescaled image series were characterized using semivariogram analysis. Results for NDVI and its component bands show, as expected, that decreasing spatial resolution leads to decreasing spatial variability and increasing spatial dependence. However, compared to the observed data, the rescaled images contain more persistent spatial structure that exhibits limited variation in both spatial dependence and spatial heterogeneity. Rescaling via simple block averaging fails to consider the effect of scene object shape and extent on spatial information. As the features

Ultrafast Mid-IR Nonlinear Optics in Gas-filled Hollow-core Photonic Crystal Fibers

DEFF Research Database (Denmark)

Habib, Selim

Invention of hollow-core fiber has been proven an ideal medium to study light-gas interaction. Tight confinement of light inside hollowcore fiber allows unremitting and tailored interaction between light and gas over long distances. In this work, we used a special kind of hollowcore fiber − hollow......-core anti-resonant (HC-AR) fiber to study the various nonlinear effects filled with Raman free noble gas. One of the main striking features of HC-AR fiber is that ∼99.99% light can be guided inside the central hollow-core region, which significantly enhances damage threshold level. HC-AR fiber can sustain...... be tuned by simply changing the pressure of the gas while at the same time providing extremely wide transparency ranges. In this thesis, we propose several low-loss broadband guidance HC-AR fibers and investigate soliton-plasma dynamics using HC-AR fiber filled with noble gas in the mid-IR. The combined...

NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Mid Shelf Reef (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83 (NCEI Accession 0131860)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the Mid Shelf Reef south of St. Thomas, US Virgin IslandsNOAA's NOS/NCCOS/CCMA Biogeography Team,...

MID-INFRARED PROPERTIES OF OH MEGAMASER HOST GALAXIES. I. SPITZER IRS LOW- AND HIGH-RESOLUTION SPECTROSCOPY

International Nuclear Information System (INIS)

Willett, Kyle W.; Darling, Jeremy; Spoon, Henrik W. W.; Charmandaris, Vassilis; Armus, Lee

2011-01-01

We present mid-infrared spectra and photometry from the Infrared Spectrograph on the Spitzer Space Telescope for 51 OH megamasers (OHMs), along with 15 galaxies confirmed to have no megamaser emission above L OH = 10 2.3 L sun . The majority of galaxies display moderate-to-deep 9.7 μm amorphous silicate absorption, with OHM galaxies showing stronger average absorption and steeper 20-30 μm continuum emission than non-masing galaxies. Emission from multiple polycyclic aromatic hydrocarbons (PAHs), especially at 6.2, 7.7, and 11.3 μm, is detected in almost all systems. Fine-structure atomic emission (including [Ne II], [Ne III], [S III], and [S IV]) and multiple H 2 rotational transitions are observed in more than 90% of the sample. A subset of galaxies show emission from rarer atomic lines, such as [Ne V], [O IV], and [Fe II]. Fifty percent of the OHMs show absorption from water ice and hydrogenated amorphous carbon grains, while absorption features from CO 2 , HCN, C 2 H 2 , and crystalline silicates are also seen in several OHMs. Column densities of OH derived from 34.6 μm OH absorption are similar to those derived from 1667 MHz OH absorption in non-masing galaxies, indicating that the abundance of masing molecules is similar for both samples. This data paper presents full mid-infrared spectra for each galaxy, along with measurements of line fluxes and equivalent widths, absorption feature depths, and spectral indices.

Mid-Infrared Properties of OH Megamaser Host Galaxies. I. Spitzer IRS Low- and High-Resolution Spectroscopy

Science.gov (United States)

Willett, Kyle W.; Darling, Jeremy; Spoon, Henrik W. W.; Charmandaris, Vassilis; Armus, Lee

2011-03-01

We present mid-infrared spectra and photometry from the Infrared Spectrograph on the Spitzer Space Telescope for 51 OH megamasers (OHMs), along with 15 galaxies confirmed to have no megamaser emission above L OH = 102.3 L sun. The majority of galaxies display moderate-to-deep 9.7 μm amorphous silicate absorption, with OHM galaxies showing stronger average absorption and steeper 20-30 μm continuum emission than non-masing galaxies. Emission from multiple polycyclic aromatic hydrocarbons (PAHs), especially at 6.2, 7.7, and 11.3 μm, is detected in almost all systems. Fine-structure atomic emission (including [Ne II], [Ne III], [S III], and [S IV]) and multiple H2 rotational transitions are observed in more than 90% of the sample. A subset of galaxies show emission from rarer atomic lines, such as [Ne V], [O IV], and [Fe II]. Fifty percent of the OHMs show absorption from water ice and hydrogenated amorphous carbon grains, while absorption features from CO2, HCN, C2H2, and crystalline silicates are also seen in several OHMs. Column densities of OH derived from 34.6 μm OH absorption are similar to those derived from 1667 MHz OH absorption in non-masing galaxies, indicating that the abundance of masing molecules is similar for both samples. This data paper presents full mid-infrared spectra for each galaxy, along with measurements of line fluxes and equivalent widths, absorption feature depths, and spectral indices.

Optimization of super-resolution processing using incomplete image sets in PET imaging.

Science.gov (United States)

Chang, Guoping; Pan, Tinsu; Clark, John W; Mawlawi, Osama R

2008-12-01

Super-resolution (SR) techniques are used in PET imaging to generate a high-resolution image by combining multiple low-resolution images that have been acquired from different points of view (POVs). The number of low-resolution images used defines the processing time and memory storage necessary to generate the SR image. In this paper, the authors propose two optimized SR implementations (ISR-1 and ISR-2) that require only a subset of the low-resolution images (two sides and diagonal of the image matrix, respectively), thereby reducing the overall processing time and memory storage. In an N x N matrix of low-resolution images, ISR-1 would be generated using images from the two sides of the N x N matrix, while ISR-2 would be generated from images across the diagonal of the image matrix. The objective of this paper is to investigate whether the two proposed SR methods can achieve similar performance in contrast and signal-to-noise ratio (SNR) as the SR image generated from a complete set of low-resolution images (CSR) using simulation and experimental studies. A simulation, a point source, and a NEMA/IEC phantom study were conducted for this investigation. In each study, 4 (2 x 2) or 16 (4 x 4) low-resolution images were reconstructed from the same acquired data set while shifting the reconstruction grid to generate images from different POVs. SR processing was then applied in each study to combine all as well as two different subsets of the low-resolution images to generate the CSR, ISR-1, and ISR-2 images, respectively. For reference purpose, a native reconstruction (NR) image using the same matrix size as the three SR images was also generated. The resultant images (CSR, ISR-1, ISR-2, and NR) were then analyzed using visual inspection, line profiles, SNR plots, and background noise spectra. The simulation study showed that the contrast and the SNR difference between the two ISR images and the CSR image were on average 0.4% and 0.3%, respectively. Line profiles of

Monitoring combat wound healing by IR hyperspectral imaging

Science.gov (United States)

Howle, Chris R.; Spear, Abigail M.; Gazi, Ehsan; Crane, Nicole J.

2016-03-01

In recent conflicts, battlefield injuries consist largely of extensive soft injuries from blasts and high energy projectiles, including gunshot wounds. Repair of these large, traumatic wounds requires aggressive surgical treatment, including multiple surgical debridements to remove devitalised tissue and to reduce bacterial load. Identifying those patients with wound complications, such as infection and impaired healing, could greatly assist health care teams in providing the most appropriate and personalised care for combat casualties. Candidate technologies to enable this benefit include the fusion of imaging and optical spectroscopy to enable rapid identification of key markers. Hence, a novel system based on IR negative contrast imaging (NCI) is presented that employs an optical parametric oscillator (OPO) source comprising a periodically-poled LiNbO3 (PPLN) crystal. The crystal operates in the shortwave and midwave IR spectral regions (ca. 1.5 - 1.9 μm and 2.4 - 3.8 μm, respectively). Wavelength tuning is achieved by translating the crystal within the pump beam. System size and complexity are minimised by the use of single element detectors and the intracavity OPO design. Images are composed by raster scanning the monochromatic beam over the scene of interest; the reflection and/or absorption of the incident radiation by target materials and their surrounding environment provide a method for spatial location. Initial results using the NCI system to characterise wound biopsies are presented here.

Mid-callosal plane determination using preferred directions from diffusion tensor images

Science.gov (United States)

Costa, André L.; Rittner, Letícia; Lotufo, Roberto A.; Appenzeller, Simone

2015-03-01

The corpus callosum is the major brain structure responsible for inter{hemispheric communication between neurons. Many studies seek to relate corpus callosum attributes to patient characteristics, cerebral diseases and psychological disorders. Most of those studies rely on 2D analysis of the corpus callosum in the mid-sagittal plane. However, it is common to find conflicting results among studies, once many ignore methodological issues and define the mid-sagittal plane based on precary or invalid criteria with respect to the corpus callosum. In this work we propose a novel method to determine the mid-callosal plane using the corpus callosum internal preferred diffusion directions obtained from diffusion tensor images. This plane is analogous to the mid-sagittal plane, but intended to serve exclusively as the corpus callosum reference. Our method elucidates the great potential the directional information of the corpus callosum fibers have to indicate its own referential. Results from experiments with five image pairs from distinct subjects, obtained under the same conditions, demonstrate the method effectiveness to find the corpus callosum symmetric axis relative to the axial plane.

Ultrafast Silicon Photonics with Visible to Mid-Infrared Pumping of Silicon Nanocrystals.

Science.gov (United States)

Diroll, Benjamin T; Schramke, Katelyn S; Guo, Peijun; Kortshagen, Uwe R; Schaller, Richard D

2017-10-11

Dynamic optical control of infrared (IR) transparency and refractive index is achieved using boron-doped silicon nanocrystals excited with mid-IR optical pulses. Unlike previous silicon-based optical switches, large changes in transmittance are achieved without a fabricated structure by exploiting strong light coupling of the localized surface plasmon resonance (LSPR) produced from free holes of p-type silicon nanocrystals. The choice of optical excitation wavelength allows for selectivity between hole heating and carrier generation through intraband or interband photoexcitation, respectively. Mid-IR optical pumping heats the free holes of p-Si nanocrystals to effective temperatures greater than 3500 K. Increases of the hole effective mass at high effective hole temperatures lead to a subpicosecond change of the dielectric function, resulting in a redshift of the LSPR, modulating mid-IR transmission by as much as 27%, and increasing the index of refraction by more than 0.1 in the mid-IR. Low hole heat capacity dictates subpicosecond hole cooling, substantially faster than carrier recombination, and negligible heating of the Si lattice, permitting mid-IR optical switching at terahertz repetition frequencies. Further, the energetic distribution of holes at high effective temperatures partially reverses the Burstein-Moss effect, permitting the modulation of transmittance at telecommunications wavelengths. The results presented here show that doped silicon, particularly in micro- or nanostructures, is a promising dynamic metamaterial for ultrafast IR photonics.

Far-field super-resolution imaging of resonant multiples

KAUST Repository

Guo, Bowen

2016-05-20

We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of the resonant multiples. This procedure has important applications in earthquake and exploration seismology, radar, sonar, LIDAR (light detection and ranging), and ultrasound imaging, where the multiples can be used to make high-resolution images.

Super-resolution for asymmetric resolution of FIB-SEM 3D imaging using AI with deep learning.

Science.gov (United States)

Hagita, Katsumi; Higuchi, Takeshi; Jinnai, Hiroshi

2018-04-12

Scanning electron microscopy equipped with a focused ion beam (FIB-SEM) is a promising three-dimensional (3D) imaging technique for nano- and meso-scale morphologies. In FIB-SEM, the specimen surface is stripped by an ion beam and imaged by an SEM installed orthogonally to the FIB. The lateral resolution is governed by the SEM, while the depth resolution, i.e., the FIB milling direction, is determined by the thickness of the stripped thin layer. In most cases, the lateral resolution is superior to the depth resolution; hence, asymmetric resolution is generated in the 3D image. Here, we propose a new approach based on an image-processing or deep-learning-based method for super-resolution of 3D images with such asymmetric resolution, so as to restore the depth resolution to achieve symmetric resolution. The deep-learning-based method learns from high-resolution sub-images obtained via SEM and recovers low-resolution sub-images parallel to the FIB milling direction. The 3D morphologies of polymeric nano-composites are used as test images, which are subjected to the deep-learning-based method as well as conventional methods. We find that the former yields superior restoration, particularly as the asymmetric resolution is increased. Our super-resolution approach for images having asymmetric resolution enables observation time reduction.

Sparsity-Based Super Resolution for SEM Images.

Science.gov (United States)

Tsiper, Shahar; Dicker, Or; Kaizerman, Idan; Zohar, Zeev; Segev, Mordechai; Eldar, Yonina C

2017-09-13

The scanning electron microscope (SEM) is an electron microscope that produces an image of a sample by scanning it with a focused beam of electrons. The electrons interact with the atoms in the sample, which emit secondary electrons that contain information about the surface topography and composition. The sample is scanned by the electron beam point by point, until an image of the surface is formed. Since its invention in 1942, the capabilities of SEMs have become paramount in the discovery and understanding of the nanometer world, and today it is extensively used for both research and in industry. In principle, SEMs can achieve resolution better than one nanometer. However, for many applications, working at subnanometer resolution implies an exceedingly large number of scanning points. For exactly this reason, the SEM diagnostics of microelectronic chips is performed either at high resolution (HR) over a small area or at low resolution (LR) while capturing a larger portion of the chip. Here, we employ sparse coding and dictionary learning to algorithmically enhance low-resolution SEM images of microelectronic chips-up to the level of the HR images acquired by slow SEM scans, while considerably reducing the noise. Our methodology consists of two steps: an offline stage of learning a joint dictionary from a sequence of LR and HR images of the same region in the chip, followed by a fast-online super-resolution step where the resolution of a new LR image is enhanced. We provide several examples with typical chips used in the microelectronics industry, as well as a statistical study on arbitrary images with characteristic structural features. Conceptually, our method works well when the images have similar characteristics, as microelectronics chips do. This work demonstrates that employing sparsity concepts can greatly improve the performance of SEM, thereby considerably increasing the scanning throughput without compromising on analysis quality and resolution.

Fluorescent microthermographic imaging

Energy Technology Data Exchange (ETDEWEB)

Barton, D.L.

1993-09-01

In the early days of microelectronics, design rules and feature sizes were large enough that sub-micron spatial resolution was not needed. Infrared or IR thermal techniques were available that calculated the object`s temperature from infrared emission. There is a fundamental spatial resolution limitation dependent on the wavelengths of light being used in the image formation process. As the integrated circuit feature sizes began to shrink toward the one micron level, the limitations imposed on IR thermal systems became more pronounced. Something else was needed to overcome this limitation. Liquid crystals have been used with great success, but they lack the temperature measurement capabilities of other techniques. The fluorescent microthermographic imaging technique (FMI) was developed to meet this need. This technique offers better than 0.01{degrees}C temperature resolution and is diffraction limited to 0.3 {mu}m spatial resolution. While the temperature resolution is comparable to that available on IR systems, the spatial resolution is much better. The FMI technique provides better spatial resolution by using a temperature dependent fluorescent film that emits light at 612 nm instead of the 1.5 {mu}m to 12 {mu}m range used by IR techniques. This tutorial starts with a review of blackbody radiation physics, the process by which all heated objects emit radiation to their surroundings, in order to understand the sources of information that are available to characterize an object`s surface temperature. The processes used in infrared thermal imaging are then detailed to point out the limitations of the technique but also to contrast it with the FMI process. The FMI technique is then described in detail, starting with the fluorescent film physics and ending with a series of examples of past applications of FMI.

Automatic Detection of Changes on Mars Surface from High-Resolution Orbital Images

Science.gov (United States)

Sidiropoulos, Panagiotis; Muller, Jan-Peter

2017-04-01

Over the last 40 years Mars has been extensively mapped by several NASA and ESA orbital missions, generating a large image dataset comprised of approximately 500,000 high-resolution images (of citizen science can be employed for training and verification it is unsuitable for planetwide systematic change detection. In this work, we introduce a novel approach in planetary image change detection, which involves a batch-mode automatic change detection pipeline that identifies regions that have changed. This is tested in anger, on tens of thousands of high-resolution images over the MC11 quadrangle [5], acquired by CTX, HRSC, THEMIS-VIS and MOC-NA instruments [1]. We will present results which indicate a substantial level of activity in this region of Mars, including instances of dynamic natural phenomena that haven't been cataloged in the planetary science literature before. We will demonstrate the potential and usefulness of such an automatic approach in planetary science change detection. Acknowledgments: The research leading to these results has received funding from the STFC "MSSL Consolidated Grant" ST/K000977/1 and partial support from the European Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement n° 607379. References: [1] P. Sidiropoulos and J. - P. Muller (2015) On the status of orbital high-resolution repeat imaging of Mars for the observation of dynamic surface processes. Planetary and Space Science, 117: 207-222. [2] O. Aharonson, et al. (2003) Slope streak formation and dust deposition rates on Mars. Journal of Geophysical Research: Planets, 108(E12):5138 [3] A. McEwen, et al. (2011) Seasonal flows on warm martian slopes. Science, 333 (6043): 740-743. [4] S. Byrne, et al. (2009) Distribution of mid-latitude ground ice on mars from new impact craters. Science, 325(5948):1674-1676. [5] K. Gwinner, et al (2016) The High Resolution Stereo Camera (HRSC) of Mars Express and its approach to science analysis and mapping for Mars and

Mid-infrared pulsed laser ultrasonic testing for carbon fiber reinforced plastics.

Science.gov (United States)

Kusano, Masahiro; Hatano, Hideki; Watanabe, Makoto; Takekawa, Shunji; Yamawaki, Hisashi; Oguchi, Kanae; Enoki, Manabu

2018-03-01

Laser ultrasonic testing (LUT) can realize contactless and instantaneous non-destructive testing, but its signal-to-noise ratio must be improved in order to measure carbon fiber reinforced plastics (CFRPs). We have developed a mid-infrared (mid-IR) laser source optimal for generating ultrasonic waves in CFRPs by using a wavelength conversion device based on an optical parametric oscillator. This paper reports a comparison of the ultrasonic generation behavior between the mid-IR laser and the Nd:YAG laser. The mid-IR laser generated a significantly larger ultrasonic amplitude in CFRP laminates than a conventional Nd:YAG laser. In addition, our study revealed that the surface epoxy matrix of CFRPs plays an important role in laser ultrasonic generation. Copyright © 2017 Elsevier B.V. All rights reserved.

Near Infrared Microspectroscopy, Fluorescence Microspectroscopy, Infrared Chemical Imaging and High Resolution Nuclear Magnetic Resonance Analysis of Soybean Seeds, Somatic Embryos and Single Cells

CERN Document Server

Baianu, I C; Hofmann, N E; Korban, S S; Lozano, P; You, T; AOCS 94th Meeting, Kansas

2002-01-01

Novel methodologies are currently being developed and established for the chemical analysis of soybean seeds, embryos and single cells by Fourier Transform Infrared (FT-IR), Fourier Transform Near Infrared (FT-NIR) Microspectroscopy, Fluorescence and High-Resolution NMR (HR-NMR). The first FT-NIR chemical images of biological systems approaching one micron resolution are presented here. Chemical images obtained by FT-NIR and FT-IR Microspectroscopy are presented for oil in soybean seeds and somatic embryos under physiological conditions. FT-NIR spectra of oil and proteins were obtained for volumes as small as two cubic microns. Related, HR-NMR analyses of oil contents in somatic embryos are also presented here with nanoliter precision. Such 400 MHz 1H NMR analyses allowed the selection of mutagenized embryos with higher oil content (e.g. ~20%) compared to non-mutagenized control embryos. Moreover, developmental changes in single soybean seeds and/or somatic embryos may be monitored by FT-NIR with a precision ...

Spectral Confirmation of New Galactic LBV and WN Stars Associated With Mid-IR Nebulae

Science.gov (United States)

Stringfellow, Guy; Gvaramadze, Vasilii V.

2014-08-01

Luminous Blue Variable (LBV) stars represent an extremely rare class and short-lived phase in the lives of very luminous massive stars with high mass loss rates. Extragalactic LBVs are responsible for producing false supernovae (SN), the SN Impostors, and have been directly linked with the progenitors of actual SN, indicating the LBV phase can be a final endpoint for massive star evolution. Yet only a few confirmed LBVs have been identified in the Galaxy. Their stellar evolution is poorly constrained by observations, and the physical reason for their unstable nature, both in terms of moderate spectral and photometric variability of a few magnitudes and the giant eruptions a la η Car that rival SN explosions, remains a mystery. Newly discovered mid-IR shells act as signposts, pointing to the central massive stars (LBV and Wolf-Rayet [WR] stars) that produced them. We have undertaken a spectroscopic survey of possible progenitor stars within these shells and are discovering that many are LBVs and WN-type WR transitional stars. We propose to extend this IR spectral survey to the south to search for new progenitor stars associated with dozens of newly identified shells. This survey should result in a substantial increase of new WRs and candidate LBVs for continued future study. Spectral analysis will yield new insights into the winds and physical properties of these rare and important objects, and lead to a better understanding of the physics driving giant eruptions.

Transition-edge sensor arrays for UV-optical-IR astrophysics

International Nuclear Information System (INIS)

Burney, J.; Bay, T.J.; Barral, J.; Brink, P.L.; Cabrera, B.; Castle, J.P.; Miller, A.J.; Nam, S.; Rosenberg, D.; Romani, R.W.; Tomada, A.

2006-01-01

Our research group has developed and characterized transition-edge sensor (TES) arrays for near IR-optical-near UV astrophysical observations. These detectors have a time-stamp accuracy of 0.3μs and an energy resolution of 0.16eV for 2.33eV photons at very high rates (30kHz). We have installed a 6x6 array of these TESs in an adiabatic demagnetization refrigerator equipped with windows for direct imaging. We discuss new instrumentation progress and current data in all aspects related to successful operation of this camera system, including: detector and array performance, position dependence and cross-talk, low-temperature and readout electronics, quantum and system efficiency, IR filtering, and focus and imaging

FT-IR imaging for quantitative determination of liver fat content in non-alcoholic fatty liver.

Science.gov (United States)

Kochan, K; Maslak, E; Chlopicki, S; Baranska, M

2015-08-07

In this work we apply FT-IR imaging of large areas of liver tissue cross-section samples (∼5 cm × 5 cm) for quantitative assessment of steatosis in murine model of Non-Alcoholic Fatty Liver (NAFLD). We quantified the area of liver tissue occupied by lipid droplets (LDs) by FT-IR imaging and Oil Red O (ORO) staining for comparison. Two alternative FT-IR based approaches are presented. The first, straightforward method, was based on average spectra from tissues and provided values of the fat content by using a PLS regression model and the reference method. The second one – the chemometric-based method – enabled us to determine the values of the fat content, independently of the reference method by means of k-means cluster (KMC) analysis. In summary, FT-IR images of large size liver sections may prove to be useful for quantifying liver steatosis without the need of tissue staining.

Color image guided depth image super resolution using fusion filter

Science.gov (United States)

He, Jin; Liang, Bin; He, Ying; Yang, Jun

2018-04-01

Depth cameras are currently playing an important role in many areas. However, most of them can only obtain lowresolution (LR) depth images. Color cameras can easily provide high-resolution (HR) color images. Using color image as a guide image is an efficient way to get a HR depth image. In this paper, we propose a depth image super resolution (SR) algorithm, which uses a HR color image as a guide image and a LR depth image as input. We use the fusion filter of guided filter and edge based joint bilateral filter to get HR depth image. Our experimental results on Middlebury 2005 datasets show that our method can provide better quality in HR depth images both numerically and visually.

Analytical potential of mid-infrared detection in capillary electrophoresis and liquid chromatography: A review

International Nuclear Information System (INIS)

Kuligowski, Julia; Quintas, Guillermo; Guardia, Miguel de la; Lendl, Bernhard

2010-01-01

Literature published in the last decade concerning the use of mid-infrared spectrometry as a detection system in separation techniques employing a liquid mobile phase is reviewed. In addition to the continued use of isocratic liquid chromatographic (LC) techniques, advances in chemometric data evaluation techniques now allow the use of gradient techniques on a routine basis, thus significantly broadening the range of possible applications of LC-IR. The general trend towards miniaturized separation systems was also followed for mid-IR detection where two key developments are of special importance. Firstly, concerning on-line detection the advent of micro-fabricated flow-cells with inner volumes of only a few nL for transmission as well as attenuated total reflection measurements enabled on-line mid-IR detection in capillary LC and opened the path for the first successful realization of on-line mid-IR detection in capillary zone electrophoresis as well as micellar electrokinetic chromatography. Secondly, concerning off-line detection the use of micro-flow through dispensers now enables to concentrate eluting analytes on dried spots sized a few tens of micrometers, thus matching the dimensions for sensitive detection by mid-IR microscopy. Finally in an attempt to increase detection sensitivity of on-line mid-IR detection, mid-IR quantum cascade lasers have been used. Applications cover the field of food analysis, environmental analysis and the characterization of explosives among others. Best detection sensitivities for on-line and off-line detection have been achieved in miniaturized systems and are in the order of 50 ng and 2 ng on column, respectively.

Resolution enhancement of tri-stereo remote sensing images by super resolution methods

Science.gov (United States)

Tuna, Caglayan; Akoguz, Alper; Unal, Gozde; Sertel, Elif

2016-10-01

Super resolution (SR) refers to generation of a High Resolution (HR) image from a decimated, blurred, low-resolution (LR) image set, which can be either a single frame or multi-frame that contains a collection of several images acquired from slightly different views of the same observation area. In this study, we propose a novel application of tri-stereo Remote Sensing (RS) satellite images to the super resolution problem. Since the tri-stereo RS images of the same observation area are acquired from three different viewing angles along the flight path of the satellite, these RS images are properly suited to a SR application. We first estimate registration between the chosen reference LR image and other LR images to calculate the sub pixel shifts among the LR images. Then, the warping, blurring and down sampling matrix operators are created as sparse matrices to avoid high memory and computational requirements, which would otherwise make the RS-SR solution impractical. Finally, the overall system matrix, which is constructed based on the obtained operator matrices is used to obtain the estimate HR image in one step in each iteration of the SR algorithm. Both the Laplacian and total variation regularizers are incorporated separately into our algorithm and the results are presented to demonstrate an improved quantitative performance against the standard interpolation method as well as improved qualitative results due expert evaluations.

Bio-inspired, sub-wavelength surface structures for ultra-broadband, omni-directional anti-reflection in the mid and far IR.

Science.gov (United States)

Gonzalez, Federico Lora; Gordon, Michael J

2014-06-02

Quasi-ordered moth-eye arrays were fabricated in Si using a colloidal lithography method to achieve highly efficient, omni-directional transmission of mid and far infrared (IR) radiation. The effect of structure height and aspect ratio on transmittance and scattering was explored experimentally and modeled quantitatively using effective medium theory. The highest aspect ratio structures (AR = 9.4) achieved peak transmittance of 98%, with >85% transmission for λ = 7-30 μm. A detailed photon balance was constructed by measuring transmission, forward scattering, specular reflection and diffuse reflection to quantify optical losses due to near-field effects. In addition, angle-dependent transmission measurements showed that moth-eye structures provide superior anti-reflective properties compared to unstructured interfaces over a wide angular range (0-60° incidence). The colloidal lithography method presented here is scalable and substrate-independent, providing a general approach to realize moth-eye structures and anti-reflection in many IR-compatible material systems.

Image Quality in High-resolution and High-cadence Solar Imaging

Science.gov (United States)

Denker, C.; Dineva, E.; Balthasar, H.; Verma, M.; Kuckein, C.; Diercke, A.; González Manrique, S. J.

2018-03-01

Broad-band imaging and even imaging with a moderate bandpass (about 1 nm) provides a photon-rich environment, where frame selection (lucky imaging) becomes a helpful tool in image restoration, allowing us to perform a cost-benefit analysis on how to design observing sequences for imaging with high spatial resolution in combination with real-time correction provided by an adaptive optics (AO) system. This study presents high-cadence (160 Hz) G-band and blue continuum image sequences obtained with the High-resolution Fast Imager (HiFI) at the 1.5-meter GREGOR solar telescope, where the speckle-masking technique is used to restore images with nearly diffraction-limited resolution. The HiFI employs two synchronized large-format and high-cadence sCMOS detectors. The median filter gradient similarity (MFGS) image-quality metric is applied, among others, to AO-corrected image sequences of a pore and a small sunspot observed on 2017 June 4 and 5. A small region of interest, which was selected for fast-imaging performance, covered these contrast-rich features and their neighborhood, which were part of Active Region NOAA 12661. Modifications of the MFGS algorithm uncover the field- and structure-dependency of this image-quality metric. However, MFGS still remains a good choice for determining image quality without a priori knowledge, which is an important characteristic when classifying the huge number of high-resolution images contained in data archives. In addition, this investigation demonstrates that a fast cadence and millisecond exposure times are still insufficient to reach the coherence time of daytime seeing. Nonetheless, the analysis shows that data acquisition rates exceeding 50 Hz are required to capture a substantial fraction of the best seeing moments, significantly boosting the performance of post-facto image restoration.

Initial results of a new generation dual source CT system using only an in-plane comb filter for ultra-high resolution temporal bone imaging

International Nuclear Information System (INIS)

Meyer, Mathias; Haubenreisser, Holger; Schoenberg, Stefan O.; Henzler, Thomas; Raupach, Rainer; Schmidt, Bernhard; Leidecker, Christianne; Allmendinger, Thomas; Flohr, Thomas; Lietzmann, Florian; Schad, Lothar R.

2015-01-01

To prospectively evaluate radiation dose and image quality of a third generation dual-source CT (DSCT) without z-axis filter behind the patient for temporal bone CT. Forty-five patients were either examined on a first, second, or third generation DSCT in an ultra-high-resolution (UHR) temporal bone-imaging mode. On the third generation DSCT system, the tighter focal spot of 0.2 mm 2 removesthe necessity for an additional z-axis-filter, leading to an improved z-axis radiation dose efficiency. Images of 0.4 mm were reconstructed using standard filtered-back-projection or iterative reconstruction (IR) technique for previous generations of DSCT and a novel IR algorithm for the third generation DSCT. Radiation dose and image quality were compared between the three DSCT systems. The statistically significantly highest subjective and objective image quality was evaluated for the third generation DSCT when compared to the first or second generation DSCT systems (all p < 0.05). Total effective dose was 63 %/39 % lower for the third generation examination as compared to the first and second generation DSCT. Temporal bone imaging without z-axis-UHR-filter and a novel third generation IR algorithm allows for significantly higher image quality while lowering effective dose when compared to the first two generations of DSCTs. (orig.)

Multi-example feature-constrained back-projection method for image super-resolution

Institute of Scientific and Technical Information of China (English)

Junlei Zhang; Dianguang Gai; Xin Zhang; Xuemei Li

2017-01-01

Example-based super-resolution algorithms,which predict unknown high-resolution image information using a relationship model learnt from known high- and low-resolution image pairs, have attracted considerable interest in the field of image processing. In this paper, we propose a multi-example feature-constrained back-projection method for image super-resolution. Firstly, we take advantage of a feature-constrained polynomial interpolation method to enlarge the low-resolution image. Next, we consider low-frequency images of different resolutions to provide an example pair. Then, we use adaptive k NN search to find similar patches in the low-resolution image for every image patch in the high-resolution low-frequency image, leading to a regression model between similar patches to be learnt. The learnt model is applied to the low-resolution high-frequency image to produce high-resolution high-frequency information. An iterative back-projection algorithm is used as the final step to determine the final high-resolution image.Experimental results demonstrate that our method improves the visual quality of the high-resolution image.

SINGLE FRAME SUPER RESOLUTION OF NONCOOPERATIVE IRIS IMAGES

Directory of Open Access Journals (Sweden)

Anand Deshpande

2016-11-01

Full Text Available Image super-resolution, a process to enhance image resolution, has important applications in biometrics, satellite imaging, high definition television, medical imaging, etc. The long range captured iris identification systems often suffer from low resolution and meager focus of the captured iris images. These degrade the iris recognition performance. This paper proposes enhanced iterated back projection (EIBP method to super resolute the long range captured iris polar images. The performance of proposed method is tested and analyzed on CASIA long range iris database by comparing peak signal to noise ratio (PSNR and structural similarity index (SSIM with state-of-the-art super resolution (SR algorithms. It is further analyzed by increasing the up-sampling factor. Performance analysis shows that the proposed method is superior to state-of-the-art algorithms, the peak signal-to-noise ratio improved about 0.1-1.5 dB. The results demonstrate that the proposed method is well suited to super resolve the iris polar images captured at a long distance

Super-resolution imaging applied to moving object tracking

Science.gov (United States)

Swalaganata, Galandaru; Ratna Sulistyaningrum, Dwi; Setiyono, Budi

2017-10-01

Moving object tracking in a video is a method used to detect and analyze changes that occur in an object that being observed. Visual quality and the precision of the tracked target are highly wished in modern tracking system. The fact that the tracked object does not always seem clear causes the tracking result less precise. The reasons are low quality video, system noise, small object, and other factors. In order to improve the precision of the tracked object especially for small object, we propose a two step solution that integrates a super-resolution technique into tracking approach. First step is super-resolution imaging applied into frame sequences. This step was done by cropping the frame in several frame or all of frame. Second step is tracking the result of super-resolution images. Super-resolution image is a technique to obtain high-resolution images from low-resolution images. In this research single frame super-resolution technique is proposed for tracking approach. Single frame super-resolution was a kind of super-resolution that it has the advantage of fast computation time. The method used for tracking is Camshift. The advantages of Camshift was simple calculation based on HSV color that use its histogram for some condition and color of the object varies. The computational complexity and large memory requirements required for the implementation of super-resolution and tracking were reduced and the precision of the tracked target was good. Experiment showed that integrate a super-resolution imaging into tracking technique can track the object precisely with various background, shape changes of the object, and in a good light conditions.

Imaging Lithium Atoms at Sub-Angstrom Resolution

Energy Technology Data Exchange (ETDEWEB)

O' Keefe, Michael A.; Shao-Horn, Yang

2005-01-03

John Cowley and his group at ASU were pioneers in the use of transmission electron microscopy (TEM) for high-resolution imaging. Three decades ago they achieved images showing the crystal unit cell content at better than 4A resolution. Over the years, this achievement has inspired improvements in resolution that have enabled researchers to pinpoint the positions of heavy atom columns within the cell. More recently, this ability has been extended to light atoms as resolution has improved. Sub-Angstrom resolution has enabled researchers to image the columns of light atoms (carbon, oxygen and nitrogen) that are present in many complex structures. By using sub-Angstrom focal-series reconstruction of the specimen exit surface wave to image columns of cobalt, oxygen, and lithium atoms in a transition metal oxide structure commonly used as positive electrodes in lithium rechargeable batteries, we show that the range of detectable light atoms extends to lithium. HRTEM at sub-Angstrom resolution will provide the essential role of experimental verification for the emergent nanotech revolution. Our results foreshadow those to be expected from next-generation TEMs with CS-corrected lenses and monochromated electron beams.

Resolution-recovery-embedded image reconstruction for a high-resolution animal SPECT system.

Science.gov (United States)

Zeraatkar, Navid; Sajedi, Salar; Farahani, Mohammad Hossein; Arabi, Hossein; Sarkar, Saeed; Ghafarian, Pardis; Rahmim, Arman; Ay, Mohammad Reza

2014-11-01

The small-animal High-Resolution SPECT (HiReSPECT) is a dedicated dual-head gamma camera recently designed and developed in our laboratory for imaging of murine models. Each detector is composed of an array of 1.2 × 1.2 mm(2) (pitch) pixelated CsI(Na) crystals. Two position-sensitive photomultiplier tubes (H8500) are coupled to each head's crystal. In this paper, we report on a resolution-recovery-embedded image reconstruction code applicable to the system and present the experimental results achieved using different phantoms and mouse scans. Collimator-detector response functions (CDRFs) were measured via a pixel-driven method using capillary sources at finite distances from the head within the field of view (FOV). CDRFs were then fitted by independent Gaussian functions. Thereafter, linear interpolations were applied to the standard deviation (σ) values of the fitted Gaussians, yielding a continuous map of CDRF at varying distances from the head. A rotation-based maximum-likelihood expectation maximization (MLEM) method was used for reconstruction. A fast rotation algorithm was developed to rotate the image matrix according to the desired angle by means of pre-generated rotation maps. The experiments demonstrated improved resolution utilizing our resolution-recovery-embedded image reconstruction. While the full-width at half-maximum (FWHM) radial and tangential resolution measurements of the system were over 2 mm in nearly all positions within the FOV without resolution recovery, reaching around 2.5 mm in some locations, they fell below 1.8 mm everywhere within the FOV using the resolution-recovery algorithm. The noise performance of the system was also acceptable; the standard deviation of the average counts per voxel in the reconstructed images was 6.6% and 8.3% without and with resolution recovery, respectively. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Monsoonal response to mid-holocene orbital forcing in a high resolution GCM

Directory of Open Access Journals (Sweden)

J. H. C. Bosmans

2012-04-01

Full Text Available In this study, we use a sophisticated high-resolution atmosphere-ocean coupled climate model, EC-Earth, to investigate the effect of Mid-Holocene orbital forcing on summer monsoons on both hemispheres. During the Mid-Holocene (6 ka, there was more summer insolation on the Northern Hemisphere than today, which intensified the meridional temperature and pressure gradients. Over North Africa, monsoonal precipitation is intensified through increased landward monsoon winds and moisture advection as well as decreased moisture convergence over the oceans and more convergence over land compared to the pre-industrial simulation. Precipitation also extends further north as the ITCZ shifts northward in response to the stronger poleward gradient of insolation. This increase and poleward extent is stronger than in most previous ocean-atmosphere GCM simulations. In north-westernmost Africa, precipitation extends up to 35° N. Over tropical Africa, internal feedbacks completely overcome the direct warming effect of increased insolation. We also find a weakened African Easterly Jet. Over Asia, monsoonal precipitation during the Mid-Holocene is increased as well, but the response is different than over North-Africa. There is more convection over land at the expense of convection over the ocean, but precipitation does not extend further northward, monsoon winds over the ocean are weaker and the surrounding ocean does not provide more moisture. On the Southern Hemisphere, summer insolation and the poleward insolation gradient were weaker during the Mid-Holocene, resulting in a reduced South American monsoon through decreased monsoon winds and less convection, as well as an equatorward shift in the ITCZ. This study corroborates the findings of paleodata research as well as previous model studies, while giving a more detailed account of Mid-Holocene monsoons.

Spatially Resolved Circumnuclear Dust in Centaurus A

OpenAIRE

Karovska, Margarita; Marengo, Massimo; Elvis, Martin; Fazio, Giovanni; Hora, Joseph; Hinz, Philip; Hoffmann, William; Meyer, Michael; Mamajek, Eric

2003-01-01

In this paper we present results from our exploratory mid-IR study of Centaurus A circumnuclear environment using high-angular resolution imaging at the Magellan 6.5m telescope with the MIRAC/BLINC camera. We detected emission from a compact region surrounding the nuclear source, and obtained photometry at 8.8 microns and in the N band. Our analysis suggests that the nuclear region is resolved with a size of approximately 3 pc. The mid-IR emission from this region is likely associated with co...

On the Search for Mid-IR and Pure Rotational H3+ Emission in Jupiter's Northern Aurora

Science.gov (United States)

Trafton, Laurence M.; Miller, Steve; Lacy, John H.; Greathouse, Thomas K.

2017-06-01

The first identification of astronomical spectral emission from the H3+ ion was made in Jupiter’s southern auroral region in the first overtone band near 2 μm (Drossart et al. 1989; Nature 340, 539). Trafton et al. (1989; ApJ 343, L73) also detected H3+ emission from this band near each of Jupiter’s auroral poles, but without identifying it. Shortly thereafter, Maillard et al (1990; ApJ 363, L37) detected the fundamental band emission near 4 μm. In order to determine the non-LTE column abundance of H3+, which is Jupiter’s primary ionospheric coolant, we searched in 2001-2002, initially above 10 μm, for emission lines from the H3+ pure rotational and ν1 -> ν2 difference band. This was done near the northern auroral “hot spot” at System III longitude 180 deg based on predicted theoretical frequencies. The results were reported by Trafton et al. (2009; Icarus 203, 189). No pure rotational lines were detected but there were marginal detections of two metastable difference band lines. The IR-inactive ν1 levels are populated in thermal equilibrium so these difference band lines are proxies for the pure rotational lines in establishing the total H3+ column. These marginal results are consistent with a vibrational relaxation of the ν2 level by a factor of ~6, consistent with the non-LTE calculation of Melin et al. (2005; Icarus 178, 97).We report here results from subsequent observations of Jupiter’s H3+ hot spot spectrum below 10 μm, where better detectivity was expected from the lower thermal background. However, this was offset by the reduced availability of emission from known hydrocarbons, leading to acquisition and guiding difficulty, which was resolved by offsetting from a Galilean satellite. The observations were made with the TEXES high-resolution mid-IR spectrograph at the IRTF telescope on Oct 1, 6, and 8 of 2012. Of the 18 lines predicted for this wavelength regime, half avoided blending with lines apparent in Jupiter’s auroral spectrum or

Super-resolution thermographic imaging using blind structured illumination

Science.gov (United States)

Burgholzer, Peter; Berer, Thomas; Gruber, Jürgen; Mayr, Günther

2017-07-01

Using an infrared camera for thermographic imaging allows the contactless temperature measurement of many surface pixels simultaneously. From the measured surface data, the structure below the surface, embedded inside a sample or tissue, can be reconstructed and imaged, if heated by an excitation light pulse. The main drawback in active thermographic imaging is the degradation of the spatial resolution with the imaging depth, which results in blurred images for deeper lying structures. We circumvent this degradation by using blind structured illumination combined with a non-linear joint sparsity reconstruction algorithm. We demonstrate imaging of a line pattern and a star-shaped structure through a 3 mm thick steel sheet with a resolution four times better than the width of the thermal point-spread-function. The structured illumination is realized by parallel slits cut in an aluminum foil, where the excitation coming from a flashlight can penetrate. This realization of super-resolution thermographic imaging demonstrates that blind structured illumination allows thermographic imaging without high degradation of the spatial resolution for deeper lying structures. The groundbreaking concept of super-resolution can be transferred from optics to diffusive imaging by defining a thermal point-spread-function, which gives the principle resolution limit for a certain signal-to-noise ratio, similar to the Abbe limit for a certain optical wavelength. In future work, the unknown illumination pattern could be the speckle pattern generated by a short laser pulse inside a light scattering sample or tissue.

Characteristics of Ir/Au transition edge sensor

International Nuclear Information System (INIS)

Kunieda, Yuichi; Ohno, Masashi; Nakazawa, Masaharu; Takahashi, Hiroyuki; Fukuda, Daiji; Ohkubo, Masataka

2004-01-01

A new type of microcalorimeter has been developed using a transition edge sensor (TES) and an electro-thermal feedback (ETF) method to achieve higher energy resolution and higher count rate. We are developing a superconducting Ir-based transition edge sensor (TES) microcalorimeters. To improve thermal conductivity and achieve higher energy resolution with an Ir-TES, we fabricated an Ir/Au bilayer TES by depositing gold on Ir and investigated the influence of intermediate between superconducting and normal states at the transition edge for signal responses by microscopic observation in the Ir/Au-TES. (T. Tanaka)

Compact near-IR and mid-IR cavity ring down spectroscopy device

Science.gov (United States)

Miller, J. Houston (Inventor)

2011-01-01

This invention relates to a compact cavity ring down spectrometer for detection and measurement of trace species in a sample gas using a tunable solid-state continuous-wave mid-infrared PPLN OPO laser or a tunable low-power solid-state continuous wave near-infrared diode laser with an algorithm for reducing the periodic noise in the voltage decay signal which subjects the data to cluster analysis or by averaging of the interquartile range of the data.

The Mid-Infrared Instrument for the James Webb Space Telescope, I: Introduction

DEFF Research Database (Denmark)

Rieke, G. H.; Wright, G. S.; Böker, T.

2015-01-01

MIRI (the Mid-Infrared Instrument for the James Webb Space Telescope [JWST]) operates from 5 to 28: 5 μm and combines over this range: (1) unprecedented sensitivity levels; (2) subarcsecond angular resolution; (3) freedom from atmospheric interference; (4) the inherent stability of observing...... in space; and (5) a suite of versatile capabilities including imaging, low- and medium-resolution spectroscopy (with an integral field unit), and coronagraphy. We illustrate the potential uses of this unique combination of capabilities with various science examples: (1) imaging exoplanets; (2) transit...

A Fast Algorithm for Image Super-Resolution from Blurred Observations

Directory of Open Access Journals (Sweden)

Ng Michael K

2006-01-01

Full Text Available We study the problem of reconstruction of a high-resolution image from several blurred low-resolution image frames. The image frames consist of blurred, decimated, and noisy versions of a high-resolution image. The high-resolution image is modeled as a Markov random field (MRF, and a maximum a posteriori (MAP estimation technique is used for the restoration. We show that with the periodic boundary condition, a high-resolution image can be restored efficiently by using fast Fourier transforms. We also apply the preconditioned conjugate gradient method to restore high-resolution images in the aperiodic boundary condition. Computer simulations are given to illustrate the effectiveness of the proposed approach.

RESOLVING THE ACTIVE GALACTIC NUCLEUS AND HOST EMISSION IN THE MID-INFRARED USING A MODEL-INDEPENDENT SPECTRAL DECOMPOSITION

Energy Technology Data Exchange (ETDEWEB)

Hernán-Caballero, Antonio; Alonso-Herrero, Almudena [Instituto de Física de Cantabria, CSIC-UC, Avenida de los Castros s/n, E-39005, Santander (Spain); Hatziminaoglou, Evanthia [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Spoon, Henrik W. W. [Cornell University, CRSR, Space Sciences Building, Ithaca, NY 14853 (United States); Almeida, Cristina Ramos [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Santos, Tanio Díaz [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Hönig, Sebastian F. [School of Physics and Astronomy, University of Southampton, Southampton SO18 1BJ (United Kingdom); González-Martín, Omaira [Centro de Radioastronomía y Astrofísica (CRyA-UNAM), 3-72 (Xangari), 8701, Morelia (Mexico); Esquej, Pilar, E-mail: ahernan@ifca.unican.es [Departamento de Astrofísica, Facultad de CC. Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

2015-04-20

We present results on the spectral decomposition of 118 Spitzer Infrared Spectrograph (IRS) spectra from local active galactic nuclei (AGNs) using a large set of Spitzer/IRS spectra as templates. The templates are themselves IRS spectra from extreme cases where a single physical component (stellar, interstellar, or AGN) completely dominates the integrated mid-infrared emission. We show that a linear combination of one template for each physical component reproduces the observed IRS spectra of AGN hosts with unprecedented fidelity for a template fitting method with no need to model extinction separately. We use full probability distribution functions to estimate expectation values and uncertainties for observables, and find that the decomposition results are robust against degeneracies. Furthermore, we compare the AGN spectra derived from the spectral decomposition with sub-arcsecond resolution nuclear photometry and spectroscopy from ground-based observations. We find that the AGN component derived from the decomposition closely matches the nuclear spectrum with a 1σ dispersion of 0.12 dex in luminosity and typical uncertainties of ∼0.19 in the spectral index and ∼0.1 in the silicate strength. We conclude that the emission from the host galaxy can be reliably removed from the IRS spectra of AGNs. This allows for unbiased studies of the AGN emission in intermediate- and high-redshift galaxies—currently inaccesible to ground-based observations—with archival Spitzer/IRS data and in the future with the Mid-InfraRed Instrument of the James Webb Space Telescope. The decomposition code and templates are available at http://denebola.org/ahc/deblendIRS.

Pushing the limits of spatial resolution with the Kuiper Airborne observatory

Science.gov (United States)

Lester, Daniel

1994-01-01

The study of astronomical objects at high spatial resolution in the far-IR is one of the most serious limitations to our work at these wavelengths, which carry information about the luminosity of dusty and obscured sources. At IR wavelengths shorter than 30 microns, ground based telescopes with large apertures at superb sites achieve diffraction-limited performance close to the seeing limit in the optical. At millimeter wavelengths, ground based interferometers achieve resolution that is close to this. The inaccessibility of the far-IR from the ground makes it difficult, however, to achieve complementary resolution in the far-IR. The 1983 IRAS survey, while extraordinarily sensitive, provides us with a sky map at a spatial resolution that is limited by detector size on a spatial scale that is far larger than that available in other wavelengths on the ground. The survey resolution is of order 4 min in the 100 micron bandpass, and 2 min at 60 microns (IRAS Explanatory Supplement, 1988). Information on a scale of 1' is available on some sources from the CPC. Deconvolution and image resolution using this database is one of the subjects of this workshop.

Single Image Super Resolution via Sparse Reconstruction

NARCIS (Netherlands)

Kruithof, M.C.; Eekeren, A.W.M. van; Dijk, J.; Schutte, K.

2012-01-01

High resolution sensors are required for recognition purposes. Low resolution sensors, however, are still widely used. Software can be used to increase the resolution of such sensors. One way of increasing the resolution of the images produced is using multi-frame super resolution algorithms.

Reproducible high-resolution multispectral image acquisition in dermatology

Science.gov (United States)

Duliu, Alexandru; Gardiazabal, José; Lasser, Tobias; Navab, Nassir

2015-07-01

Multispectral image acquisitions are increasingly popular in dermatology, due to their improved spectral resolution which enables better tissue discrimination. Most applications however focus on restricted regions of interest, imaging only small lesions. In this work we present and discuss an imaging framework for high-resolution multispectral imaging on large regions of interest.

Cloud top structure of Venus revealed by Subaru/COMICS mid-infrared images

Science.gov (United States)

Sato, T. M.; Sagawa, H.; Kouyama, T.; Mitsuyama, K.; Satoh, T.; Ohtsuki, S.; Ueno, M.; Kasaba, Y.; Nakamura, M.; Imamura, T.

2014-11-01

We have investigated the cloud top structure of Venus by analyzing ground-based images taken at the mid-infrared wavelengths of 8.66 μm and 11.34 μm. Venus at a solar phase angle of ∼90°, with the morning terminator in view, was observed by the Cooled Mid-Infrared Camera and Spectrometer (COMICS), mounted on the 8.2-m Subaru Telescope, during the period October 25-29, 2007. The disk-averaged brightness temperatures for the observation period are ∼230 K and ∼238 K at 8.66 μm and 11.34 μm, respectively. The obtained images with good signal-to-noise ratio and with high spatial resolution (∼200 km at the sub-observer point) provide several important findings. First, we present observational evidence, for the first time, of the possibility that the westward rotation of the polar features (the hot polar spots and the surrounding cold collars) is synchronized between the northern and southern hemispheres. Second, after high-pass filtering, the images reveal that streaks and mottled and patchy patterns are distributed over the entire disk, with typical amplitudes of ∼0.5 K, and vary from day to day. The detected features, some of which are similar to those seen in past UV images, result from inhomogeneities of both the temperature and the cloud top altitude. Third, the equatorial center-to-limb variations of brightness temperatures have a systematic day-night asymmetry, except those on October 25, that the dayside brightness temperatures are higher than the nightside brightness temperatures by 0-4 K under the same viewing geometry. Such asymmetry would be caused by the propagation of the migrating semidiurnal tide. Finally, by applying the lapse rates deduced from previous studies, we demonstrate that the equatorial center-to-limb curves in the two spectral channels give access to two parameters: the cloud scale height H and the cloud top altitude zc. The acceptable models for data on October 25 are obtained at H = 2.4-4.3 km and zc = 66-69 km; this supports

Isotope specific resolution recovery image reconstruction in high resolution PET imaging

NARCIS (Netherlands)

Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to

Atomic resolution images of graphite in air

Energy Technology Data Exchange (ETDEWEB)

Grigg, D.A.; Shedd, G.M.; Griffis, D.; Russell, P.E.

1988-12-01

One sample used for proof of operation for atomic resolution in STM is highly oriented pyrolytic graphite (HOPG). This sample has been imaged with many different STM`s obtaining similar results. Atomic resolution images of HOPG have now been obtained using an STM designed and built at the Precision Engineering Center. This paper discusses the theoretical predictions and experimental results obtained in imaging of HOPG.

Low drive field amplitude for improved image resolution in magnetic particle imaging.

Science.gov (United States)

Croft, Laura R; Goodwill, Patrick W; Konkle, Justin J; Arami, Hamed; Price, Daniel A; Li, Ada X; Saritas, Emine U; Conolly, Steven M

2016-01-01

Magnetic particle imaging (MPI) is a new imaging technology that directly detects superparamagnetic iron oxide nanoparticles. The technique has potential medical applications in angiography, cell tracking, and cancer detection. In this paper, the authors explore how nanoparticle relaxation affects image resolution. Historically, researchers have analyzed nanoparticle behavior by studying the time constant of the nanoparticle physical rotation. In contrast, in this paper, the authors focus instead on how the time constant of nanoparticle rotation affects the final image resolution, and this reveals nonobvious conclusions for tailoring MPI imaging parameters for optimal spatial resolution. The authors first extend x-space systems theory to include nanoparticle relaxation. The authors then measure the spatial resolution and relative signal levels in an MPI relaxometer and a 3D MPI imager at multiple drive field amplitudes and frequencies. Finally, these image measurements are used to estimate relaxation times and nanoparticle phase lags. The authors demonstrate that spatial resolution, as measured by full-width at half-maximum, improves at lower drive field amplitudes. The authors further determine that relaxation in MPI can be approximated as a frequency-independent phase lag. These results enable the authors to accurately predict MPI resolution and sensitivity across a wide range of drive field amplitudes and frequencies. To balance resolution, signal-to-noise ratio, specific absorption rate, and magnetostimulation requirements, the drive field can be a low amplitude and high frequency. Continued research into how the MPI drive field affects relaxation and its adverse effects will be crucial for developing new nanoparticles tailored to the unique physics of MPI. Moreover, this theory informs researchers how to design scanning sequences to minimize relaxation-induced blurring for better spatial resolution or to exploit relaxation-induced blurring for MPI with

Metal-Mesh Optical Filter Technology for Mid IR, Far IR, and Submillimeter, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The innovative, high transmission band-pass filter technology proposed here is an improvement in multilayer metal-mesh filter design and manufacture for the far IR...

Innovative monolithic detector for tri-spectral (THz, IR, Vis) imaging

Science.gov (United States)

Pocas, S.; Perenzoni, M.; Massari, N.; Simoens, F.; Meilhan, J.; Rabaud, W.; Martin, S.; Delplanque, B.; Imperinetti, P.; Goudon, V.; Vialle, C.; Arnaud, A.

2012-10-01

Fusion of multispectral images has been explored for many years for security and used in a number of commercial products. CEA-Leti and FBK have developed an innovative sensor technology that gathers monolithically on a unique focal plane arrays, pixels sensitive to radiation in three spectral ranges that are terahertz (THz), infrared (IR) and visible. This technology benefits of many assets for volume market: compactness, full CMOS compatibility on 200mm wafers, advanced functions of the CMOS read-out integrated circuit (ROIC), and operation at room temperature. The ROIC houses visible APS diodes while IR and THz detections are carried out by microbolometers collectively processed above the CMOS substrate. Standard IR bolometric microbridges (160x160 pixels) are surrounding antenna-coupled bolometers (32X32 pixels) built on a resonant cavity customized to THz sensing. This paper presents the different technological challenges achieved in this development and first electrical and sensitivity experimental tests.

Overcoming Registration Uncertainty in Image Super-Resolution: Maximize or Marginalize?

Directory of Open Access Journals (Sweden)

Andrew Zisserman

2007-01-01

Full Text Available In multiple-image super-resolution, a high-resolution image is estimated from a number of lower-resolution images. This usually involves computing the parameters of a generative imaging model (such as geometric and photometric registration, and blur and obtaining a MAP estimate by minimizing a cost function including an appropriate prior. Two alternative approaches are examined. First, both registrations and the super-resolution image are found simultaneously using a joint MAP optimization. Second, we perform Bayesian integration over the unknown image registration parameters, deriving a cost function whose only variables of interest are the pixel values of the super-resolution image. We also introduce a scheme to learn the parameters of the image prior as part of the super-resolution algorithm. We show examples on a number of real sequences including multiple stills, digital video, and DVDs of movies.

Mid-infrared spectroscopy in skin cancer cell type identification

Science.gov (United States)

Kastl, Lena; Kemper, Björn; Lloyd, Gavin R.; Nallala, Jayakrupakar; Stone, Nick; Naranjo, Valery; Penaranda, Francisco; Schnekenburger, Jürgen

2017-07-01

Mid infrared spectroscopy samples were developed for the analysis of skin tumor cell types and three dimensional tissue phantoms towards the application of midIR spectroscopy for fast and reliable skin cancer diagnostics.

Development of wide-band, time and energy resolving, optical photon detectors with application to imaging astronomy

International Nuclear Information System (INIS)

Miller, A.J.; Cabrera, B.; Romani, R.W.; Figueroa-Feliciano, E.; Nam, S.W.; Clarke, R.M.

2000-01-01

Superconducting transition edge sensors (TESs) are showing promise for the wide-band spectroscopy of individual photons from the mid-infrared (IR), through the optical, and into the near ultraviolet (UV). Our TES sensors are ∼20 μm square, 40 nm thick tungsten (W) films with a transition temperature of about 80 mK. We typically attain an energy resolution of 0.15 eV FWHM over the optical range with relative timing resolution of 100 ns. Single photon events with sub-microsecond risetimes and few microsecond falltimes have been achieved allowing count rates in excess of 30 kHz per pixel. Additionally, tungsten is approximately 50% absorptive in the optical (dropping to 10% in the IR) giving these devices an intrinsically high quantum efficiency. These combined traits make our detectors attractive for fast spectrophotometers and photon-starved applications such as wide-band, time and energy resolved astronomical observations. We present recent results from our work toward the fabrication and testing of the first TES optical photon imaging arrays

RISING FROM THE ASHES: MID-INFRARED RE-BRIGHTENING OF THE IMPOSTOR SN 2010da IN NGC 300

Energy Technology Data Exchange (ETDEWEB)

Lau, Ryan M.; Ressler, Michael E. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Kasliwal, Mansi M.; Jencson, Jacob [California Institute of Technology, Pasadena, CA 91125 (United States); Bond, Howard E.; Monson, Andrew J. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Smith, Nathan [Steward Observatory, University of Arizona, Tuscon, AZ 85721 (United States); Fox, Ori D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Carlon, Robert; Dykhoff, Devin; Gehrz, Robert [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, SE, University of Minnesota, Minneapolis, MN 55455 (United States); Cody, Ann Marie [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Contreras, Carlos [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Hsiao, Eric [Department of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL 32306 (United States); Khan, Rubab [NASA Goddard Space Flight Center, MC 665, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Masci, Frank [Infrared Processing and Analysis Center, California Institute of Technology, M/S 100-22, Pasadena, CA 91125 (United States); Monard, L. A. G. [Bronberg and Kleinkaroo Observatories, P.O. Box 281, Calitzdorp 6660, Western Cape (South Africa); Morrell, Nidia; Phillips, Mark [Carnegie Institution of Washington, Las Campanas Observatory, Colina el Pino, Casilla 601, La Serena (Chile)

2016-10-20

We present multi-epoch mid-infrared (IR) photometry and the optical discovery observations of the “impostor” supernova (SN) 2010da in NGC 300 using new and archival Spitzer Space Telescope images and ground-based observatories. The mid-infrared counterpart of SN 2010da was detected as Spitzer Infrared Intensive Transient Survey (SPIRITS) 14bme in the SPIRITS, an ongoing systematic search for IR transients. Before erupting on 2010 May 24, the SN 2010da progenitor exhibited a constant mid-IR flux at 3.6 and only a slight ∼10% decrease at 4.5 μ m between 2003 November and 2007 December. A sharp increase in the 3.6 μ m flux followed by a rapid decrease measured ∼150 days before and ∼80 days after the initial outburst, respectively, reveal a mid-IR counterpart to the coincident optical and high luminosity X-ray outbursts. At late times, after the outburst (∼2000 days), the 3.6 and 4.5 μ m emission increased to over a factor of two times the progenitor flux and is currently observed (as of 2016 Feb) to be fading, but still above the progenitor flux. We attribute the re-brightening mid-IR emission to continued dust production and increasing luminosity of the surviving system associated with SN 2010da. We analyze the evolution of the dust temperature ( T {sub d} ∼ 700–1000 K), mass ( M {sub d} ∼ 0.5–3.8 × 10{sup −7} M {sub ⊙}), luminosity ( L {sub IR} ∼ 1.3–3.5 × 10{sup 4} L {sub ⊙}), and the equilibrium temperature radius ( R {sub eq} ∼ 6.4–12.2 au) in order to resolve the nature of SN 2010da. We address the leading interpretation of SN 2010da as an eruption from a luminous blue variable high-mass X-ray binary (HMXB) system. We propose that SN 2010da is instead a supergiant (sg)B[e]-HMXB based on similar luminosities and dust masses exhibited by two other known sgB[e]-HMXB systems. Additionally, the SN 2010da progenitor occupies a similar region on a mid-IR color–magnitude diagram (CMD) with known sgB[e] stars in the Large

Linear mixing model applied to coarse resolution satellite data

Science.gov (United States)

Holben, Brent N.; Shimabukuro, Yosio E.

1992-01-01

A linear mixing model typically applied to high resolution data such as Airborne Visible/Infrared Imaging Spectrometer, Thematic Mapper, and Multispectral Scanner System is applied to the NOAA Advanced Very High Resolution Radiometer coarse resolution satellite data. The reflective portion extracted from the middle IR channel 3 (3.55 - 3.93 microns) is used with channels 1 (0.58 - 0.68 microns) and 2 (0.725 - 1.1 microns) to run the Constrained Least Squares model to generate fraction images for an area in the west central region of Brazil. The derived fraction images are compared with an unsupervised classification and the fraction images derived from Landsat TM data acquired in the same day. In addition, the relationship betweeen these fraction images and the well known NDVI images are presented. The results show the great potential of the unmixing techniques for applying to coarse resolution data for global studies.

Diffuse-reflectance fourier-transform mid-infrared spectroscopy as a method of characterizing changes in soil organic matter

Science.gov (United States)

Diffuse-Reflectance Fourier-Transform Mid-Infrared Spectroscopy (MidIR) can identify the presence of important organic functional groups in soil organic matter (SOM). Soils contain myriad organic and inorganic components that absorb in the MidIR so spectral interpretation needs to be validated in or...

HRTEM imaging of atoms at sub-Angstroem resolution

International Nuclear Information System (INIS)

O'Keefe, Michael A.; Allard, Lawrence F.; Blom, Douglas A.

2005-01-01

John Cowley and his group at Arizona State University pioneered the use of transmission electron microscopy for high-resolution imaging. Images were achieved three decades ago showing the crystal unit cell content at better than 4 A resolution. This achievement enabled researchers to pinpoint the positions of heavy atom columns within the unit cell. Lighter atoms appear as resolution is improved to sub-Angstroem levels. Currently, advanced microscopes can image the columns of the light atoms (carbon, oxygen, nitrogen) that are present in many complex structures, and even the lithium atoms present in some battery materials. Sub-Angstroem imaging, initially achieved by focal-series reconstruction of the specimen exit surface wave, will become commonplace for next-generation electron microscopes with C s -corrected lenses and monochromated electron beams. Resolution can be quantified in terms of peak separation and inter-peak minimum, but the limits imposed on the attainable resolution by the properties of the microscope specimen need to be considered. At extreme resolution the 'size' of atoms can mean that they will not be resolved even when spaced farther apart than the resolution of the microscope. (author)

HRTEM Imaging of Atoms at Sub-Angstrom Resolution

Energy Technology Data Exchange (ETDEWEB)

O' Keefe, Michael A.; Allard, Lawrence F.; Blom, Douglas A.

2005-04-06

John Cowley and his group at Arizona State University pioneered the use of transmission electron microscopy (TEM) for high-resolution imaging. Images were achieved three decades ago showing the crystal unit cell content at better than 4 Angstrom resolution. This achievement enabled researchers to pinpoint the positions of heavy atom columns within the unit cell. Lighter atoms appear as resolution is improved to sub-Angstrom levels. Currently, advanced microscopes can image the columns of the light atoms (carbon, oxygen, nitrogen) that are present in many complex structures, and even the lithium atoms present in some battery materials. Sub-Angstrom imaging, initially achieved by focal-series reconstruction of the specimen exit surface wave, will become common place for next-generation electron microscopes with CS-corrected lenses and monochromated electron beams. Resolution can be quantified in terms of peak separation and inter-peak minimum, but the limits imposed on the attainable resolution by the properties of the micro-scope specimen need to be considered. At extreme resolution the ''size'' of atoms can mean that they will not be resolved even when spaced farther apart than the resolution of the microscope.

Far-IR measurements at Cerro Toco, Chile: FIRST, REFIR, and AERI

Science.gov (United States)

Cageao, Richard P.; Alford, J. Ashley; Johnson, David G.; Kratz, David P.; Mlynczak, Martin G.

2010-09-01

In mid-2009, the Radiative Heating in the Underexplored Bands Campaign II (RHUBC-II) was conducted from Cerro Toco, Chile, a high, dry, remote mountain plateau, 23°S , 67.8°W at 5.4km, in the Atacama Desert of Northern Chile. From this site, dominant IR water vapor absorption bands and continuum, saturated when viewed from the surface at lower altitudes, or in less dry locales, were investigated in detail, elucidating infrared (IR) absorption and emission in the atmosphere. Three Fourier Transform InfraRed (FTIR) instruments were at the site, the Far-Infrared Spectroscopy of the Troposphere (FIRST), the Radiation Explorer in the Far Infrared (REFIR), and the Atmospheric Emitted Radiance Interferometer (AERI). In a side-by-side comparison, these measured atmospheric downwelling radiation, with overlapping spectral coverage from 5 to 100μm (2000 to 100cm-1), and instrument spectral resolutions from 0.5 to 0.643cm-1, unapodized. In addition to the FTIR and other ground-based IR and microwave instrumentation, pressure/temperature/relative humidity measuring sondes, for atmospheric profiles to 18km, were launched from the site several times a day. The derived water vapor profiles, determined at times matching the FTIR measurement times, were used to model atmospheric radiative transfer. Comparison of instrument data, all at the same spectral resolution, and model calculations, are presented along with a technique for determining adjustments to line-by-line calculation continuum models. This was a major objective of the campaign.

Self-triggered image intensifier tube for high-resolution UHECR imaging detector

CERN Document Server

Sasaki, M; Jobashi, M

2003-01-01

The authors have developed a self-triggered image intensifier tube with high-resolution imaging capability. An image detected by a first image intensifier tube as an electrostatic lens with a photocathode diameter of 100 mm is separated by a half-mirror into a path for CCD readout (768x494 pixels) and a fast control to recognize and trigger the image. The proposed system provides both a high signal-to-noise ratio to improve single photoelectron detection and excellent spatial resolution between 207 and 240 mu m rendering this device a potentially essential tool for high-energy physics and astrophysics experiments, as well as high-speed photography. When combined with a 1-arcmin resolution optical system with 50 deg. field-of-view proposed by the present authors, the observation of ultra high-energy cosmic rays and high-energy neutrinos using this device is expected, leading to revolutionary progress in particle astrophysics as a complementary technique to traditional astronomical observations at multiple wave...

High-resolution SPECT for small-animal imaging

International Nuclear Information System (INIS)

Qi Yujin

2006-01-01

This article presents a brief overview of the development of high-resolution SPECT for small-animal imaging. A pinhole collimator has been used for high-resolution animal SPECT to provide better spatial resolution and detection efficiency in comparison with a parallel-hole collimator. The theory of imaging characteristics of the pinhole collimator is presented and the designs of the pinhole aperture are discussed. The detector technologies used for the development of small-animal SPECT and the recent advances are presented. The evolving trend of small-animal SPECT is toward a multi-pinhole and a multi-detector system to obtain a high resolution and also a high detection efficiency. (authors)

Super-resolution imaging of subcortical white matter using stochastic optical reconstruction microscopy (STORM) and super-resolution optical fluctuation imaging (SOFI)

Science.gov (United States)

Hainsworth, A. H.; Lee, S.; Patel, A.; Poon, W. W.; Knight, A. E.

2018-01-01

Aims The spatial resolution of light microscopy is limited by the wavelength of visible light (the ‘diffraction limit’, approximately 250 nm). Resolution of sub-cellular structures, smaller than this limit, is possible with super resolution methods such as stochastic optical reconstruction microscopy (STORM) and super-resolution optical fluctuation imaging (SOFI). We aimed to resolve subcellular structures (axons, myelin sheaths and astrocytic processes) within intact white matter, using STORM and SOFI. Methods Standard cryostat-cut sections of subcortical white matter from donated human brain tissue and from adult rat and mouse brain were labelled, using standard immunohistochemical markers (neurofilament-H, myelin-associated glycoprotein, glial fibrillary acidic protein, GFAP). Image sequences were processed for STORM (effective pixel size 8–32 nm) and for SOFI (effective pixel size 80 nm). Results In human, rat and mouse, subcortical white matter high-quality images for axonal neurofilaments, myelin sheaths and filamentous astrocytic processes were obtained. In quantitative measurements, STORM consistently underestimated width of axons and astrocyte processes (compared with electron microscopy measurements). SOFI provided more accurate width measurements, though with somewhat lower spatial resolution than STORM. Conclusions Super resolution imaging of intact cryo-cut human brain tissue is feasible. For quantitation, STORM can under-estimate diameters of thin fluorescent objects. SOFI is more robust. The greatest limitation for super-resolution imaging in brain sections is imposed by sample preparation. We anticipate that improved strategies to reduce autofluorescence and to enhance fluorophore performance will enable rapid expansion of this approach. PMID:28696566

Super-resolution imaging of subcortical white matter using stochastic optical reconstruction microscopy (STORM) and super-resolution optical fluctuation imaging (SOFI).

Science.gov (United States)

Hainsworth, A H; Lee, S; Foot, P; Patel, A; Poon, W W; Knight, A E

2017-07-11

The spatial resolution of light microscopy is limited by the wavelength of visible light (the 'diffraction limit', approximately 250 nm). Resolution of sub-cellular structures, smaller than this limit, is possible with super resolution methods such as stochastic optical reconstruction microscopy (STORM) and super-resolution optical fluctuation imaging (SOFI). We aimed to resolve subcellular structures (axons, myelin sheaths and astrocytic processes) within intact white matter, using STORM and SOFI. Standard cryostat-cut sections of subcortical white matter from donated human brain tissue and from adult rat and mouse brain were labelled, using standard immunohistochemical markers (neurofilament-H, myelin-associated glycoprotein, glial fibrillary acidic protein, GFAP). Image sequences were processed for STORM (effective pixel size 8-32 nm) and for SOFI (effective pixel size 80 nm). In human, rat and mouse, subcortical white matter high-quality images for axonal neurofilaments, myelin sheaths and filamentous astrocytic processes were obtained. In quantitative measurements, STORM consistently underestimated width of axons and astrocyte processes (compared with electron microscopy measurements). SOFI provided more accurate width measurements, though with somewhat lower spatial resolution than STORM. Super resolution imaging of intact cryo-cut human brain tissue is feasible. For quantitation, STORM can under-estimate diameters of thin fluorescent objects. SOFI is more robust. The greatest limitation for super-resolution imaging in brain sections is imposed by sample preparation. We anticipate that improved strategies to reduce autofluorescence and to enhance fluorophore performance will enable rapid expansion of this approach. © 2017 British Neuropathological Society.

MID-INFRARED ATOMIC FINE-STRUCTURE EMISSION-LINE SPECTRA OF LUMINOUS INFRARED GALAXIES: SPITZER/IRS SPECTRA OF THE GOALS SAMPLE

Energy Technology Data Exchange (ETDEWEB)

Inami, H. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Armus, L.; Stierwalt, S.; Díaz-Santos, T.; Surace, J.; Howell, J.; Marshall, J. [Spitzer Science Center, California Institute of Technology, CA 91125 (United States); Charmandaris, V. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003 Heraklion (Greece); Groves, B. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Kewley, L. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Petric, A. [Department of Astronomy, California Institute of Technology, MS 320-47, Pasadena, CA 91125 (United States); Rich, J. [The Observatories, Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Haan, S. [CSIRO Astronomy and Space Science, Marsfield, NSW 2122 (Australia); Evans, A. S. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Mazzarella, J.; Lord, S. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Appleton, P. [NASA Herschel Science Center, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Spoon, H. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Frayer, D. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Matsuhara, H., E-mail: inami@noao.edu [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan); and others

2013-11-10

We present the data and our analysis of mid-infrared atomic fine-structure emission lines detected in Spitzer/Infrared Spectrograph high-resolution spectra of 202 local Luminous Infrared Galaxies (LIRGs) observed as part of the Great Observatories All-sky LIRG Survey (GOALS). We readily detect emission lines of [S IV], [Ne II], [Ne V], [Ne III], [S III]{sub 18.7{sub μm}}, [O IV], [Fe II], [S III]{sub 33.5{sub μm}}, and [Si II]. More than 75% of these galaxies are classified as starburst-dominated sources in the mid-infrared, based on the [Ne V]/[Ne II] line flux ratios and equivalent width of the 6.2 μm polycyclic aromatic hydrocarbon feature. We compare ratios of the emission-line fluxes to those predicted from stellar photo-ionization and shock-ionization models to constrain the physical and chemical properties of the gas in the starburst LIRG nuclei. Comparing the [S IV]/[Ne II] and [Ne III]/[Ne II] line ratios to the Starburst99-Mappings III models with an instantaneous burst history, the emission-line ratios suggest that the nuclear starbursts in our LIRGs have ages of 1-4.5 Myr, metallicities of 1-2 Z{sub ☉}, and ionization parameters of 2-8 × 10{sup 7} cm s{sup –1}. Based on the [S III]{sub 33.5{sub μm}}/[S III]{sub 18.7{sub μm}} ratios, the electron density in LIRG nuclei is typically one to a few hundred cm{sup –3}, with a median electron density of ∼300 cm{sup –3}, for those sources above the low density limit for these lines. We also find that strong shocks are likely present in 10 starburst-dominated sources of our sample. A significant fraction of the GOALS sources (80) have resolved neon emission-line profiles (FWHM ≥600 km s{sup –1}) and five show clear differences in the velocities of the [Ne III] or [Ne V] emission lines, relative to [Ne II], of more than 200 km s{sup –1}. Furthermore, six starburst and five active galactic nucleus dominated LIRGs show a clear trend of increasing line width with ionization potential

Efficient femtosecond mid-infrared pulse generation by dispersivewave radiation in bulk lithium niobate crystal

DEFF Research Database (Denmark)

Zhou, Binbin; Guo, Hairun; Bache, Morten

2014-01-01

We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8–2.92 µm are generated using the single pump wavelengths from 1.25–1.45 µm.......We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8–2.92 µm are generated using the single pump wavelengths from 1.25–1.45 µm....

Computed tomography with selectable image resolution

International Nuclear Information System (INIS)

Dibianca, F.A.; Dallapiazza, D.G.

1981-01-01

A computed tomography system x-ray detector has a central group of half-width detector elements and groups of full-width elements on each side of the central group. To obtain x-ray attenuation data for whole body layers, the half-width elements are switched effectively into paralleled pairs so all elements act like full-width elements and an image of normal resolution is obtained. For narrower head layers, the elements in the central group are used as half-width elements so resolution which is twice as great as normal is obtained. The central group is also used in the half-width mode and the outside groups are used in the full-width mode to obtain a high resolution image of a body zone within a full body layer. In one embodiment data signals from the detector are switched by electronic multiplexing and in another embodiment a processor chooses the signals for the various kinds of images that are to be reconstructed. (author)

Section on High Resolution Optical Imaging (HROI)

Data.gov (United States)

Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

Simulation of Thermal Processes in Metamaterial MM-to-IR Converter for MM-wave Imager

International Nuclear Information System (INIS)

Zagubisalo, Peter S; Paulish, Andrey G; Kuznetsov, Sergey A

2014-01-01

The main characteristics of MM-wave image detector were simulated by means of accurate numerical modelling of thermophysical processes in a metamaterial MM-to-IR converter. The converter represents a multilayer structure consisting of an ultra thin resonant metamaterial absorber and a perfect emissive layer. The absorber consists of a dielectric self-supporting film that is metallized from both sides. A micro-pattern is fabricated from one side. Resonant absorption of the MM waves induces the converter heating that yields enhancement of IR emission from the emissive layer. IR emission is detected by IR camera. In this contribution an accurate numerical model for simulation of the thermal processes in the converter structure was created by using COMSOL Multiphysics software. The simulation results are in a good agreement with experimental results that validates the model. The simulation shows that the real time operation is provided for the converter thickness less than 3 micrometers and time response can be improved by decreasing of the converter thickness. The energy conversion efficiency of MM waves into IR radiation is over 80%. The converter temperature increase is a linear function of a MM-wave radiation power within three orders of the dynamic range. The blooming effect and ways of its reducing are also discussed. The model allows us to choose the ways of converter structure optimization and improvement of image detector parameters

SU-E-I-82: Improving CT Image Quality for Radiation Therapy Using Iterative Reconstruction Algorithms and Slightly Increasing Imaging Doses

International Nuclear Information System (INIS)

Noid, G; Chen, G; Tai, A; Li, X

2014-01-01

Purpose: Iterative reconstruction (IR) algorithms are developed to improve CT image quality (IQ) by reducing noise without diminishing spatial resolution or contrast. For CT in radiation therapy (RT), slightly increasing imaging dose to improve IQ may be justified if it can substantially enhance structure delineation. The purpose of this study is to investigate and to quantify the IQ enhancement as a result of increasing imaging doses and using IR algorithms. Methods: CT images were acquired for phantoms, built to evaluate IQ metrics including spatial resolution, contrast and noise, with a variety of imaging protocols using a CT scanner (Definition AS Open, Siemens) installed inside a Linac room. Representative patients were scanned once the protocols were optimized. Both phantom and patient scans were reconstructed using the Sinogram Affirmed Iterative Reconstruction (SAFIRE) and the Filtered Back Projection (FBP) methods. IQ metrics of the obtained CTs were compared. Results: IR techniques are demonstrated to preserve spatial resolution as measured by the point spread function and reduce noise in comparison to traditional FBP. Driven by the reduction in noise, the contrast to noise ratio is doubled by adopting the highest SAFIRE strength. As expected, increasing imaging dose reduces noise for both SAFIRE and FBP reconstructions. The contrast to noise increases from 3 to 5 by increasing the dose by a factor of 4. Similar IQ improvement was observed on the CTs for selected patients with pancreas and prostrate cancers. Conclusion: The IR techniques produce a measurable enhancement to CT IQ by reducing the noise. Increasing imaging dose further reduces noise independent of the IR techniques. The improved CT enables more accurate delineation of tumors and/or organs at risk during RT planning and delivery guidance

Digital Signal Processing Based on a Clustering Algorithm for Ir/Au TES Microcalorimeter

Science.gov (United States)

Zen, N.; Kunieda, Y.; Takahashi, H.; Hiramoto, K.; Nakazawa, M.; Fukuda, D.; Ukibe, M.; Ohkubo, M.

2006-02-01

In recent years, cryogenic microcalorimeters using their superconducting transition edge have been under development for possible application to the research for astronomical X-ray observations. To improve the energy resolution of superconducting transition edge sensors (TES), several correction methods have been developed. Among them, a clustering method based on digital signal processing has recently been proposed. In this paper, we applied the clustering method to Ir/Au bilayer TES. This method resulted in almost a 10% improvement in the energy resolution. Conversely, from the point of view of imaging X-ray spectroscopy, we applied the clustering method to pixellated Ir/Au-TES devices. We will thus show how a clustering method which sorts signals by their shapes is also useful for position identification

Influences of image resolution on herbaceous root morphological parameters

Directory of Open Access Journals (Sweden)

ZHANG Zeyou

2014-06-01

Full Text Available Root images of four herbaceous species (including Plantago virginica,Solidago canadensis,Conyza canadensis and Erigeron philadelphicus were obtained by using EPSON V7000 scanner with different resolutions.Root morphological parameters including root length,diameter,volume and area were determined by using a WinRhizo root analyzing software.The results show a distinct influence of image resolution on root morphological parameter.For different herbaceous species,the optimal resolutions of root images,which would produce an acceptable precision with relative short time,vary with different species.For example,a resolution of 200 dpi was recommended for the root images of Plantago virginica and S.Canadensis, while 400 dpi for Conyza canadensis and Erigeron philadelphicus.

Optical Remote Sensing for Fence-Line Monitoring using Open-Path Quantum Cascade Laser (QCL) mono-static system for multiple target compounds in the Mid IR 7-13um (Fingerprint) region.

Science.gov (United States)

Zemek, P. G.

2017-12-01

Quantum Cascade Lasers (QCLs) are quickly replacing Tunable Diode Lasers (TDL) for multi-target species identification and quantification in both extractive and open-path (OP) Optical Remote Sensing (ORS) fence-line instrumentation. As was seen with TDL incorporation and pricing drops as the adoption by the telecommunications industry and its current scaling has improved robustness and pricing, the QCL is also, albiet more slowly, becoming a mature market. There are several advantages of QCLs over conventional TDLs such as improved brightness and beam density, high resolution, as well as the incorporation of external etalons or internal gratings to scan over wide spectral areas. QCLs typically operate in the Mid infra-red (MIR) as opposed to the Near-Infrared (NIR) region used with TDL. The MidIR is a target rich absorption band area where compounds have high absorbtivity coefficients resulting in better detection limits as compared to TDL instruments. The use of novel chemometrics and more sensitive non-cryo-cooled detectors has allowed some of the first QCL open-path instruments in both active and passive operation. Data and field studies of one of the newest QCL OP systems is presented that allows one system to measure multiple target compounds. Multiple QCL spectral regions may be stitched together to increase the capability of QCLs over TDL OP systems. A comparison of several ORS type systems will be presented.

Attenuated total reflection-Fourier transform infrared imaging of large areas using inverted prism crystals and combining imaging and mapping.

Science.gov (United States)

Chan, K L Andrew; Kazarian, Sergei G

2008-10-01

Attenuated total reflection-Fourier transform infrared (ATR-FT-IR) imaging is a very useful tool for capturing chemical images of various materials due to the simple sample preparation and the ability to measure wet samples or samples in an aqueous environment. However, the size of the array detector used for image acquisition is often limited and there is usually a trade off between spatial resolution and the field of view (FOV). The combination of mapping and imaging can be used to acquire images with a larger FOV without sacrificing spatial resolution. Previous attempts have demonstrated this using an infrared microscope and a Germanium hemispherical ATR crystal to achieve images of up to 2.5 mm x 2.5 mm but with varying spatial resolution and depth of penetration across the imaged area. In this paper, we demonstrate a combination of mapping and imaging with a different approach using an external optics housing for large ATR accessories and inverted ATR prisms to achieve ATR-FT-IR images with a large FOV and reasonable spatial resolution. The results have shown that a FOV of 10 mm x 14 mm can be obtained with a spatial resolution of approximately 40-60 microm when using an accessory that gives no magnification. A FOV of 1.3 mm x 1.3 mm can be obtained with spatial resolution of approximately 15-20 microm when using a diamond ATR imaging accessory with 4x magnification. No significant change in image quality such as spatial resolution or depth of penetration has been observed across the whole FOV with this method and the measurement time was approximately 15 minutes for an image consisting of 16 image tiles.

Tracing the Jet Contribution to the Mid-IR over the 2005 Outburst of GRO J1655-40 via Broadband Spectral Modeling

Science.gov (United States)

Migliari, S.; Tomsick, J. A.; Markoff, S.; Kalemci, E.; Bailyn, C. D.; Buxton, M.; Corbel, S; Fender, R. P.; Kaaret, P.

2007-01-01

We present new results from a multi-wavelength (radio/infrared/optical/X-ray) study of the black hole Xray binary GRO 51655-40 during its 2005 outburst. We detected, for the first time, mid-infrared emission at 24 micron from the compact jet of a black hole X-ray binary during its hard state, when the source shows emission from a radio compact jet, as well as a strong non-thermal hard X-ray component. These detections strongly constrain the optically thick part of the synchrotron spectrum of the compact jet, which is consistent with it being flat over 4 orders of magnitude in frequency. Moreover, using this unprecedented coverage, and especially thanks to the new Spitzer observations, we can test broadband disk and jet models during the hard state. Two of the hard-state broadband spectra are reasonably well fitted using a jet model with parameters that overall are similar to those previously found for Cyg X-1 and GX 339-4. Differences are also present; most notably, the jet power in GRO J1655-40 appears to be a factor of at least approximately 3-5 higher (depending on the distance) than those of Cyg X-1 and GX-339-4 at comparable disk luminosities. Furthermore, a few discrepancies between the model and the data, previously not found for the other two black hole systems for which there was no mid-IR/IR and optical coverage, are evident, and will help to constrain and refine theoretical models.

Automated Recognition of Vegetation and Water Bodies on the Territory of Megacities in Satellite Images of Visible and IR Bands

Science.gov (United States)

Mozgovoy, Dmitry k.; Hnatushenko, Volodymyr V.; Vasyliev, Volodymyr V.

2018-04-01

Vegetation and water bodies are a fundamental element of urban ecosystems, and water mapping is critical for urban and landscape planning and management. A methodology of automated recognition of vegetation and water bodies on the territory of megacities in satellite images of sub-meter spatial resolution of the visible and IR bands is proposed. By processing multispectral images from the satellite SuperView-1A, vector layers of recognized plant and water objects were obtained. Analysis of the results of image processing showed a sufficiently high accuracy of the delineation of the boundaries of recognized objects and a good separation of classes. The developed methodology provides a significant increase of the efficiency and reliability of updating maps of large cities while reducing financial costs. Due to the high degree of automation, the proposed methodology can be implemented in the form of a geo-information web service functioning in the interests of a wide range of public services and commercial institutions.

Single image super-resolution based on convolutional neural networks

Science.gov (United States)

Zou, Lamei; Luo, Ming; Yang, Weidong; Li, Peng; Jin, Liujia

2018-03-01

We present a deep learning method for single image super-resolution (SISR). The proposed approach learns end-to-end mapping between low-resolution (LR) images and high-resolution (HR) images. The mapping is represented as a deep convolutional neural network which inputs the LR image and outputs the HR image. Our network uses 5 convolution layers, which kernels size include 5×5, 3×3 and 1×1. In our proposed network, we use residual-learning and combine different sizes of convolution kernels at the same layer. The experiment results show that our proposed method performs better than the existing methods in reconstructing quality index and human visual effects on benchmarked images.

Yb-fiber-pumped mid-infrared picosecond optical parametric oscillator tunable across 6.2-6.7 µm

Science.gov (United States)

Kumar, S. Chaitanya; Casals, J. Canals; Parsa, S.; Zawilski, K. T.; Schunemann, P. G.; Ebrahim-Zadeh, M.

2018-06-01

We report a high-average-power picosecond optical parametric oscillator (OPO) tunable in the mid-infrared (mid-IR) based on CdSiP2 synchronously pumped by an Yb-fiber laser at 80 MHz repetition rate. Successful operation of this high-repetition-rate singly-resonant picosecond OPO has been enabled by the improved CSP crystal quality over a long interaction length. The OPO can be tuned across 1264-1284 nm in the near-IR signal and 6205-6724 nm in the mid-IR idler by temperature tuning the CSP crystal over 39-134 °C. By deploying a 5% output coupler for the resonant signal, we have extracted up to 44 mW of average power in the near-IR and up to 95 mW of non-resonant idler power at 6205 nm at 6.3% total conversion efficiency, with > 50 mW over > 55% of the mid-IR tuning range. We have investigated temperature-tuning characteristics of the OPO and compared the data with the theoretical calculations using the recent Sellmeier and thermo-optic coefficients for CdSiP2. The signal pulses from the OPO exhibit a Gaussian pulse duration of 19 ps centered at 1284 nm. We have also studied the output power stability of the OPO, resulting in a passive stability better than 1.9% rms for the near-IR signal and 2.4% rms for the mid-IR idler, measured over > 17 h, with both beams in high spatial quality.

High resolution transmission imaging without lenses

International Nuclear Information System (INIS)

Rodenburg, J M; Hurst, A C; Maiden, A

2010-01-01

The whole history of transmission imaging has been dominated by the lens, whether used in visible-light optics, electron optics or X-ray optics. Lenses can be thought of as a very efficient method of processing a wave front scattered from an object into an image of that object. An alternative approach is to undertake this image-formation process using a computational technique. The crudest scattering experiment is to simply record the intensity of a diffraction pattern. Recent progress in so-called diffractive imaging has shown that it is possible to recover the phase of a scattered wavefield from its diffraction pattern alone, as long as the object (or the illumination on the object) is of finite extent. In this paper we present results from a very efficient phase retrieval method which can image infinitely large fields of view. It may have important applications in improving resolution in electron microscopy, or at least allowing low specification microscopes to achieve resolution comparable to state-of-the-art machines.

Generation and mid-IR measurement of a gas-phase to predict security parameters of aviation jet fuel.

Science.gov (United States)

Gómez-Carracedo, M P; Andrade, J M; Calviño, M A; Prada, D; Fernández, E; Muniategui, S

2003-07-27

The worldwide use of kerosene as aviation jet fuel makes its safety considerations of most importance not only for aircraft security but for the workers' health (chronic and/or acute exposure). As most kerosene risks come from its vapours, this work focuses on predicting seven characteristics (flash point, freezing point, % of aromatics and four distillation points) which assess its potential hazards. Two experimental devices were implemented in order to, first, generate a kerosene vapour phase and, then, to measure its mid-IR spectrum. All the working conditions required to generate the gas phase were optimised either in a univariate or a multivariate (SIMPLEX) approach. Next, multivariate prediction models were deployed using partial least squares regression and it was found that both the average prediction errors and precision parameters were satisfactory, almost always well below the reference figures.

Subarcsecond observations of NGC 7538 IRS 1: Continuum distribution and dynamics of molecular gas

Energy Technology Data Exchange (ETDEWEB)

Zhu, Lei; Shi, Hui [National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China); Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Wright, M. C. H. [Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720 (United States); Sandell, Göran [SOFIA-USRA, NASA Ames Research Center, MS 232-12, Building N232, Rm. 146, P.O. Box 1, Moffett Field, CA 94035-0001 (United States); Wu, Yue-Fang [Department of Astronomy, Peking University, Beijing 100871 (China); Brogan, Crystal; Corder, Stuartt, E-mail: lzhu@nao.cas.cn [NRAO, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

2013-12-10

We report new results based on the analysis of the Submillimeter Array (SMA) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) observations of NGC 7538 IRS 1 at 1.3 and 3.4 mm with subarcsecond resolutions. With angular resolutions ∼0.''7, the SMA and CARMA observations show that the continuum emission at 1.3 and 3.4 mm from the hyper-compact H II region IRS 1 is dominated by a compact source with a tail-like extended structure to the southwest of IRS 1. With a CARMA B-array image at 1.3 mm convolved to 0.''1, we resolve the hyper-compact H II region into two components: an unresolved hyper-compact core, and a north-south extension with linear sizes of <270 AU and ∼2000 AU, respectively. The fine structure observed with CARMA is in good agreement with the previous Very Large Array results at centimeter wavelengths, suggesting that the hyper-compact H II region at the center of IRS 1 is associated with an ionized bipolar outflow. We image the molecular lines OCS(19-18) and CH{sub 3}CN(12-11) as well as {sup 13}CO(2-1) surrounding IRS 1, showing a velocity gradient along the southwest-northeast direction. The spectral line profiles in {sup 13}CO(2-1), CO(2-1), and HCN(1-0) observed toward IRS 1 show broad redshifted absorption, providing evidence for gas infall with rates in the range of 3-10 × 10{sup –3} M {sub ☉} yr{sup –1} inferred from our observations.

Frontiers in Chemical Physics

Energy Technology Data Exchange (ETDEWEB)

Bowlan, Pamela Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-02

These are slides dealing with frontiers in chemical physics. The following topics are covered: Time resolving chemistry with ultrashort pulses in the 0.1-40 THz spectral range; Example: Mid-infrared absorption spectrum of the intermediate state CH₂OO; Tracking reaction dynamics through changes in the spectra; Single-shot measurement of the mid-IR absorption dynamics; Applying 2D coherent mid-IR spectroscopy to learn more about transition states; Time resolving chemical reactions at a catalysis using mid-IR and THz pulses; Studying topological insulators requires a surface sensitive probe; Nonlinear phonon dynamics in Bi₂Se₃; THz-pump, SHG-probe as a surface sensitive coherent 2D spectroscopy; Nanometer and femtosecond spatiotemporal resolution mid-IR spectroscopy; Coherent two-dimensional THz/mid-IR spectroscopy with 10nm spatial resolution; Pervoskite oxides as catalysts; Functionalized graphene for catalysis; Single-shot spatiotemporal measurements; Spatiotemporal pulse measurement; Intense, broad-band THz/mid-IR generation with organic crystals.

Super-Resolution of Plant Disease Images for the Acceleration of Image-based Phenotyping and Vigor Diagnosis in Agriculture.

Science.gov (United States)

Yamamoto, Kyosuke; Togami, Takashi; Yamaguchi, Norio

2017-11-06

Unmanned aerial vehicles (UAVs or drones) are a very promising branch of technology, and they have been utilized in agriculture-in cooperation with image processing technologies-for phenotyping and vigor diagnosis. One of the problems in the utilization of UAVs for agricultural purposes is the limitation in flight time. It is necessary to fly at a high altitude to capture the maximum number of plants in the limited time available, but this reduces the spatial resolution of the captured images. In this study, we applied a super-resolution method to the low-resolution images of tomato diseases to recover detailed appearances, such as lesions on plant organs. We also conducted disease classification using high-resolution, low-resolution, and super-resolution images to evaluate the effectiveness of super-resolution methods in disease classification. Our results indicated that the super-resolution method outperformed conventional image scaling methods in spatial resolution enhancement of tomato disease images. The results of disease classification showed that the accuracy attained was also better by a large margin with super-resolution images than with low-resolution images. These results indicated that our approach not only recovered the information lost in low-resolution images, but also exerted a beneficial influence on further image analysis. The proposed approach will accelerate image-based phenotyping and vigor diagnosis in the field, because it not only saves time to capture images of a crop in a cultivation field but also secures the accuracy of these images for further analysis.

Fiber optic lasers with emission to the region 2-3 μm of IR medium

International Nuclear Information System (INIS)

Anzuelo Sanchez, G.; Osuna Galan, I.; Camas Anzueto, J.; Martinez Rios, A.; Selvas Aguilar, R.

2009-01-01

We present recent advances in laser emission in the 2-2-5 μm mid-IR, using a chalcogenide fiber with low loss and a high Raman gain in the region 2-10 μm. We present a review of fiber lasers operating in 2-3 μm of the mid IR. (Author)

Industrial radiography with Ir-192 using computed radiographic technique

International Nuclear Information System (INIS)

Ngernvijit, Narippawaj; Punnachaiya, Suvit; Chankow, Nares; Sukbumperng, Ampai; Thong-Aram, Decho

2003-01-01

The aim of this research is to study the utilization of a low activity Ir-192 gamma source for industrial radiographic testing using the Computed Radiography (CR) system. Due to a photo-salbutamol Imaging Plate (I P) using in CR is much more radiation sensitive than a type II film with lead foil intensifying screen, the exposure time with CR can be significantly reduced. For short-lived gamma-ray source like Ir-192 source, the exposure time must be proportionally increased until it is not practical particularly for thick specimens. Generally, when the source decays to an activity of about 5 Ci or less, it will be returned to the manufacturer as a radioactive waste. In this research, the optimum conditions for radiography of a 20 mm thick welded steel sample with 2.4 Ci Ir-192 was investigated using the CR system with high resolution image plate, i.e. type Bas-SR of the Fuji Film Co. Ltd. The I P was sandwiched by a pair of 0.25 mm thick Pb intensifying sere en. Low energy scattered radiations was filtered by placing another Pb sheet with a thickness of 3 mm under the cassette. It was found that the CR image could give a contrast sensitivity of 2.5 % using only 3-minute exposure time which was comparable to the image taken by the type II film with Pb intensifying screen using the exposure time of 45 minutes

Technical Note: Measuring contrast- and noise-dependent spatial resolution of an iterative reconstruction method in CT using ensemble averaging

Energy Technology Data Exchange (ETDEWEB)

Yu, Lifeng, E-mail: yu.lifeng@mayo.edu; Vrieze, Thomas J.; Leng, Shuai; Fletcher, Joel G.; McCollough, Cynthia H. [Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States)

2015-05-15

Purpose: The spatial resolution of iterative reconstruction (IR) in computed tomography (CT) is contrast- and noise-dependent because of the nonlinear regularization. Due to the severe noise contamination, it is challenging to perform precise spatial-resolution measurements at very low-contrast levels. The purpose of this study was to measure the spatial resolution of a commercially available IR method using ensemble-averaged images acquired from repeated scans. Methods: A low-contrast phantom containing three rods (7, 14, and 21 HU below background) was scanned on a 128-slice CT scanner at three dose levels (CTDI{sub vol} = 16, 8, and 4 mGy). Images were reconstructed using two filtered-backprojection (FBP) kernels (B40 and B20) and a commercial IR method (sinogram affirmed iterative reconstruction, SAFIRE, Siemens Healthcare) with two strength settings (I40-3 and I40-5). The same scan was repeated 100 times at each dose level. The modulation transfer function (MTF) was calculated based on the edge profile measured on the ensemble-averaged images. Results: The spatial resolution of the two FBP kernels, B40 and B20, remained relatively constant across contrast and dose levels. However, the spatial resolution of the two IR kernels degraded relative to FBP as contrast or dose level decreased. For a given dose level at 16 mGy, the MTF{sub 50%} value normalized to the B40 kernel decreased from 98.4% at 21 HU to 88.5% at 7 HU for I40-3 and from 97.6% to 82.1% for I40-5. At 21 HU, the relative MTF{sub 50%} value decreased from 98.4% at 16 mGy to 90.7% at 4 mGy for I40-3 and from 97.6% to 85.6% for I40-5. Conclusions: A simple technique using ensemble averaging from repeated CT scans can be used to measure the spatial resolution of IR techniques in CT at very low contrast levels. The evaluated IR method degraded the spatial resolution at low contrast and high noise levels.

Registration accuracy and image quality of time averaged mid-position CT scans for liver SBRT

NARCIS (Netherlands)

Kruis, Matthijs F.; van de Kamer, Jeroen B.; Sonke, Jan-Jakob; Jansen, Edwin P. M.; van Herk, Marcel

2013-01-01

The purpose was to validate the accuracy of motion models derived from deformable registration from four-dimensional computed tomography (4DCT) and breath-hold contrast enhanced computed tomography (BHCCT) scans for liver SBRT. Additionally, the image quality of the time averaged mid-position (MidP)

High-Resolution Imaging of Axial Volcano, Juan de Fuca ridge.

Science.gov (United States)

Arnulf, A. F.; Harding, A. J.; Kent, G. M.

2014-12-01

To date, seismic experiments have been key in our understanding of the internal structure of volcanic systems. However, most experiments, especially subaerial-based, are often restricted to refraction geometries with limited numbers of sources and receivers, and employ smoothing constraints required by tomographic inversions that produce smoothed and blurry images with spatial resolutions well below the length scale of important features that define these magmatic systems. Taking advantage of the high density of sources and receivers from multichannel seismic (MCS) data should, in principle, allow detailed images of velocity and reflectivity to be recovered. Unfortunately, the depth of mid-ocean ridges has the detrimental effect of concealing critical velocity information behind the seafloor reflection, preventing first arrival travel-time tomographic approaches from imaging the shallowest and most heterogeneous part of the crust. To overcome the limitations of the acquisition geometry, here we are using an innovative multistep approach. We combine a synthetic ocean bottom experiment (SOBE), 3-D traveltime tomography, 2D elastic full waveform and a reverse time migration (RTM) formalism, and present one of the most detailed imagery to date of a massive and complex magmatic system beneath Axial seamount, an active submarine volcano that lies at the intersection of the Juan de Fuca ridge and the Cobb-Eickelberg seamount chain. We present high-resolution images along 12 seismic lines that span the volcano. We refine the extent/volume of the main crustal magma reservoir that lies beneath the central caldera. We investigate the extent, volume and physical state of a secondary magma body present to the southwest and study its connections with the main magma reservoir. Additionally, we present a 3D tomographic model of the entire volcano that reveals a subsiding caldera floor that provides a near perfect trap for the ponding of lava flows, supporting a "trapdoor

Widely-tunable and sensitive optical sensor for multi-species detection in the mid-IR

KAUST Repository

Alquaity, Awad

2017-10-05

Pulsed cavity ringdown spectroscopy (CRDS) technique was used to develop a novel widely-tunable laser-based sensor for sensitive measurements of ethylene, propene, 1-butene and allene in the mid-IR. The use of an external-cavity quantum cascade laser (EC-QCL) enabled the sensor to cover a wide wavelength range from 10 to 11.1 µm (900 – 1000 cm-1) to detect multiple gases relevant to combustion and environment. The sensor operation was validated in a room-temperature static cell using well-characterized absorption lines of carbon dioxide near 938.69 cm-1 and 974.62 cm-1. Detection limits for ethylene, propene, 1-butene, and allene were measured to be 17, 134, 754 and 378 ppb, respectively, at 296 K and 760 Torr for a single-pass path-length of 70 cm. The excellent sensitivity of the optical sensor enabled it to measure the aforementioned gases at levels smaller than 1% of their recommended exposure limits. To the best of our knowledge, this is one of the first successful applications of the pulsed CRDS technique to measure trace levels of multiple gases in the 10 – 11 µm wavelength region.

Widely-tunable and sensitive optical sensor for multi-species detection in the mid-IR

KAUST Repository

Alquaity, Awad; Alsaif, Bidoor; Farooq, Aamir

2017-01-01

Pulsed cavity ringdown spectroscopy (CRDS) technique was used to develop a novel widely-tunable laser-based sensor for sensitive measurements of ethylene, propene, 1-butene and allene in the mid-IR. The use of an external-cavity quantum cascade laser (EC-QCL) enabled the sensor to cover a wide wavelength range from 10 to 11.1 µm (900 – 1000 cm-1) to detect multiple gases relevant to combustion and environment. The sensor operation was validated in a room-temperature static cell using well-characterized absorption lines of carbon dioxide near 938.69 cm-1 and 974.62 cm-1. Detection limits for ethylene, propene, 1-butene, and allene were measured to be 17, 134, 754 and 378 ppb, respectively, at 296 K and 760 Torr for a single-pass path-length of 70 cm. The excellent sensitivity of the optical sensor enabled it to measure the aforementioned gases at levels smaller than 1% of their recommended exposure limits. To the best of our knowledge, this is one of the first successful applications of the pulsed CRDS technique to measure trace levels of multiple gases in the 10 – 11 µm wavelength region.

Mid-IR spectrometer for mobile, real-time urban NO2 measurements

Science.gov (United States)

Morten Hundt, P.; Müller, Michael; Mangold, Markus; Tuzson, Béla; Scheidegger, Philipp; Looser, Herbert; Hüglin, Christoph; Emmenegger, Lukas

2018-05-01

Detailed knowledge about the urban NO2 concentration field is a key element for obtaining accurate pollution maps and individual exposure estimates. These are required for improving the understanding of the impact of ambient NO2 on human health and for related air quality measures. However, city-scale NO2 concentration maps with high spatio-temporal resolution are still lacking, mainly due to the difficulty of accurate measurement of NO2 at the required sub-ppb level precision. We contribute to close this gap through the development of a compact instrument based on mid-infrared laser absorption spectroscopy. Leveraging recent advances in infrared laser and detection technology and a novel circular absorption cell, we demonstrate the feasibility and robustness of this technique for demanding mobile applications. A fully autonomous quantum cascade laser absorption spectrometer (QCLAS) has been successfully deployed on a tram, performing long-term and real-time concentration measurements of NO2 in the city of Zurich (Switzerland). For ambient NO2 concentrations, the instrument demonstrated a precision of 0.23 ppb at one second time resolution and of 0.03 ppb after 200 s averaging. Whilst the combined uncertainty estimated for the retrieved spectroscopic values was less than 5 %, laboratory intercomparison measurements with standard CLD instruments revealed a systematic NO2 wall loss of about 10 % within the laser spectrometer. For the field campaign, the QCLAS has been referenced to a CLD using urban atmospheric air, despite the potential cross sensitivity of CLD to other nitrogen containing compounds. However, this approach allowed a direct comparison and continuous validation of the spectroscopic data to measurements at regulatory air quality monitoring (AQM) stations along the tram-line. The analysis of the recorded high-resolution time series allowed us to gain more detailed insights into the spatio-temporal concentration distribution of NO2 in an urban

SPECT imaging with resolution recovery

International Nuclear Information System (INIS)

Bronnikov, A. V.

2011-01-01

Single-photon emission computed tomography (SPECT) is a method of choice for imaging spatial distributions of radioisotopes. Many applications of this method are found in nuclear industry, medicine, and biomedical research. We study mathematical modeling of a micro-SPECT system by using a point-spread function (PSF) and implement an OSEM-based iterative algorithm for image reconstruction with resolution recovery. Unlike other known implementations of the OSEM algorithm, we apply en efficient computation scheme based on a useful approximation of the PSF, which ensures relatively fast computations. The proposed approach can be applied with the data acquired with any type of collimators, including parallel-beam fan-beam, cone-beam and pinhole collimators. Experimental results obtained with a micro SPECT system demonstrate high efficiency of resolution recovery. (authors)

Super-Resolution of Plant Disease Images for the Acceleration of Image-based Phenotyping and Vigor Diagnosis in Agriculture

Directory of Open Access Journals (Sweden)

Kyosuke Yamamoto

2017-11-01

Full Text Available Unmanned aerial vehicles (UAVs or drones are a very promising branch of technology, and they have been utilized in agriculture—in cooperation with image processing technologies—for phenotyping and vigor diagnosis. One of the problems in the utilization of UAVs for agricultural purposes is the limitation in flight time. It is necessary to fly at a high altitude to capture the maximum number of plants in the limited time available, but this reduces the spatial resolution of the captured images. In this study, we applied a super-resolution method to the low-resolution images of tomato diseases to recover detailed appearances, such as lesions on plant organs. We also conducted disease classification using high-resolution, low-resolution, and super-resolution images to evaluate the effectiveness of super-resolution methods in disease classification. Our results indicated that the super-resolution method outperformed conventional image scaling methods in spatial resolution enhancement of tomato disease images. The results of disease classification showed that the accuracy attained was also better by a large margin with super-resolution images than with low-resolution images. These results indicated that our approach not only recovered the information lost in low-resolution images, but also exerted a beneficial influence on further image analysis. The proposed approach will accelerate image-based phenotyping and vigor diagnosis in the field, because it not only saves time to capture images of a crop in a cultivation field but also secures the accuracy of these images for further analysis.

Dynamic magnetic resonance imaging of the behavior of the mid-urethra in healthy and stress incontinent women.

Science.gov (United States)

Rinne, Kirsi Marja; Kainulainen, Sakari; Aukee, Sinikka; Heinonen, Seppo; Nilsson, Carl Gustaf

2010-03-01

Support of the mid-urethra is thought to be an essential element of urinary continence in the female. Our aim was to image the behavior of the mid-urethra in healthy volunteers and in stress urinary incontinence (SUI) patients by dynamic magnetic resonance imaging (MRI). Prospective study. Gynecology outpatient clinic association with Department of Radiology in University Hospital of Kuopio, Finland. Fifteen healthy volunteers and 40 SUI women underwent dynamic MRI at rest, during pelvic floor muscle contraction, coughing and voiding with a bladder volume of 200 ml. Our aim was to determine the precise location and movement of the mid-urethra during these activities. The co-ordinate location and movement of the mid-urethra. Continent volunteers can elevate their mid-urethra significantly higher than incontinent women. Moreover, the mid-urethra of incontinent women rotated significantly more dorsocaudally during straining and coughing than in continent women. Elevation of the mid-urethra was more marked in continent compared to urinary incontinent women on pelvic floor muscle contraction suggesting sufficient support of the urethra. Downward movement of the mid-urethra was more significant in stress incontinent women than in continent volunteers.

Localization-based super-resolution imaging of cellular structures.

Science.gov (United States)

Kanchanawong, Pakorn; Waterman, Clare M

2013-01-01

Fluorescence microscopy allows direct visualization of fluorescently tagged proteins within cells. However, the spatial resolution of conventional fluorescence microscopes is limited by diffraction to ~250 nm, prompting the development of super-resolution microscopy which offers resolution approaching the scale of single proteins, i.e., ~20 nm. Here, we describe protocols for single molecule localization-based super-resolution imaging, using focal adhesion proteins as an example and employing either photoswitchable fluorophores or photoactivatable fluorescent proteins. These protocols should also be easily adaptable to imaging a broad array of macromolecular assemblies in cells whose components can be fluorescently tagged and assemble into high density structures.

Quantifying and containing the curse of high resolution coronal imaging

Directory of Open Access Journals (Sweden)

V. Delouille

2008-10-01

Full Text Available Future missions such as Solar Orbiter (SO, InterHelioprobe, or Solar Probe aim at approaching the Sun closer than ever before, with on board some high resolution imagers (HRI having a subsecond cadence and a pixel area of about (80 km2 at the Sun during perihelion. In order to guarantee their scientific success, it is necessary to evaluate if the photon counts available at these resolution and cadence will provide a sufficient signal-to-noise ratio (SNR. For example, if the inhomogeneities in the Quiet Sun emission prevail at higher resolution, one may hope to locally have more photon counts than in the case of a uniform source. It is relevant to quantify how inhomogeneous the quiet corona will be for a pixel pitch that is about 20 times smaller than in the case of SoHO/EIT, and 5 times smaller than TRACE. We perform a first step in this direction by analyzing and characterizing the spatial intermittency of Quiet Sun images thanks to a multifractal analysis. We identify the parameters that specify the scale-invariance behavior. This identification allows next to select a family of multifractal processes, namely the Compound Poisson Cascades, that can synthesize artificial images having some of the scale-invariance properties observed on the recorded images. The prevalence of self-similarity in Quiet Sun coronal images makes it relevant to study the ratio between the SNR present at SoHO/EIT images and in coarsened images. SoHO/EIT images thus play the role of "high resolution" images, whereas the "low-resolution" coarsened images are rebinned so as to simulate a smaller angular resolution and/or a larger distance to the Sun. For a fixed difference in angular resolution and in Spacecraft-Sun distance, we determine the proportion of pixels having a SNR preserved at high resolution given a particular increase in effective area. If scale-invariance continues to prevail at smaller scales, the conclusion reached with SoHO/EIT images can be transposed

High-resolution axial MR imaging of tibial stress injuries

Directory of Open Access Journals (Sweden)

Mammoto Takeo

2012-05-01

Full Text Available Abstract Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries.

High-resolution axial MR imaging of tibial stress injuries

Science.gov (United States)

2012-01-01

Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries. PMID:22574840

α-Lipoic acid stabilized DTX/IR780 micelles for photoacoustic/fluorescence imaging guided photothermal therapy/chemotherapy of breast cancer.

Science.gov (United States)

Li, WenTing; Peng, JinRong; Yang, Qian; Chen, LiJuan; Zhang, Lan; Chen, XiaoXin; Qian, ZhiYong

2018-05-01

Micellar nanoparticles have unique advantages as carriers for therapeutic or imaging agents, owing to their smaller size and better penetration of tumors. However, some agents, due to their physical or chemical properties, are difficult to load into micelles. IR780 is one of these agents, and is also a promising near-infrared dye for fluorescence imaging (FI)/photoacoustic imaging (PAI) and cancer photothermal therapy (PTT). Its hydrophobic and high crystallization structure results in limited bioavailability in vivo. It is difficult to load into micelles constructed from an amphiphilic block polymer with relatively low molecular weight. In this study, we use computer simulation and introduce another small biomolecule, α-lipoic acid, into the micelles constructed from a mPEG-PCL copolymer, to lower the energy of molecular interaction between MPEG-PCL and IR780, and expect to enhance the loading capacity of the micelles to IR780. The introduction of α-lipoic acid decreases the energy of molecular interaction between MEPG-PCL and IR780 from -46.18 kJ mol-1 to -196.52 kJ mol-1 and increases the loading capacity and stability of the mPEG-PCL micelles to IR780, which also maintains the loading capacity to DTX. We further construct DTX/IR780 co-loaded mPEG-PCL micelles for FI/PAI dual modal imaging guided PTT/chemotherapy of cancer. By FI and PAI evaluation in vitro and in vivo, we demonstrate that the DTX/IR780 co-loaded micelles can be used as FI and PAI probes. By further evaluating the therapeutic outcome of PTT/chemotherapy co-therapy of breast cancer, we demonstrate that the DTX/IR780 co-loaded mPEG-PCL micelles can serve as promising candidates for FI and PAI guided PTT/chemotherapy of breast cancer.

Dynamic high resolution imaging of rats

International Nuclear Information System (INIS)

Miyaoka, R.S.; Lewellen, T.K.; Bice, A.N.

1990-01-01

A positron emission tomography with the sensitivity and resolution to do dynamic imaging of rats would be an invaluable tool for biological researchers. In this paper, the authors determine the biological criteria for dynamic positron emission imaging of rats. To be useful, 3 mm isotropic resolution and 2-3 second time binning were necessary characteristics for such a dedicated tomograph. A single plane in which two objects of interest could be imaged simultaneously was considered acceptable. Multi-layered detector designs were evaluated as a possible solution to the dynamic imaging and high resolution imaging requirements. The University of Washington photon history generator was used to generate data to investigate a tomograph's sensitivity to true, scattered and random coincidences for varying detector ring diameters. Intrinsic spatial uniformity advantages of multi-layered detector designs over conventional detector designs were investigated using a Monte Carlo program. As a result, a modular three layered detector prototype is being developed. A module will consist of a layer of five 3.5 mm wide crystals and two layers of six 2.5 mm wide crystals. The authors believe adequate sampling can be achieved with a stationary detector system using these modules. Economical crystal decoding strategies have been investigated and simulations have been run to investigate optimum light channeling methods for block decoding strategies. An analog block decoding method has been proposed and will be experimentally evaluated to determine whether it can provide the desired performance

Direct measuring of single-cycle mid-IR light bullets path length in LiF by the laser coloration method

Directory of Open Access Journals (Sweden)

Chekalin Sergey

2017-01-01

Full Text Available A colour-centre structure formed in a LiF crystal under filamentation of a femtosecond mid-IR laser pulse with a power slightly exceeding the critical power for self-focusing has been experimentally and theoretically investigated. A single-cycle light bullet was recorded for the first time by observation of strictly periodic oscillations for the density of the color centers induced in an isotropic LiF crystal under filamentation of a laser beam with a wavelength tuned in the range from 2600 to 3900 nm, which is due to the periodic change in the light field amplitude in the light bullet formed under filamentation under propagation in dispersive medium. The light bullet path length was not more than one millimeter.

3D FT-IR imaging spectroscopy of phase-separation in a poly(3-hydroxybutyrate)/poly(L-lactic acid) blend

Science.gov (United States)

Miriam Unger; Julia Sedlmair; Heinz W. Siesler; Carol Hirschmugl; Barbara Illman

2014-01-01

In the present study, 3D FT-IR spectroscopic imaging measurements were applied to study the phase separation of a poly(3-hydroxybutyrate) (PHB)/poly(L-lactic acid) (PLA) (50:50 wt.%) polymer blend film. While in 2D projection imaging the z-dependent information is overlapped, thereby complicating the analysis, FT-IR spectro-micro-tomography,...

All-passive pixel super-resolution of time-stretch imaging

Science.gov (United States)

Chan, Antony C. S.; Ng, Ho-Cheung; Bogaraju, Sharat C. V.; So, Hayden K. H.; Lam, Edmund Y.; Tsia, Kevin K.

2017-03-01

Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the-art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate — hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (≈2-5 GSa/s)—more than four times lower than the originally required readout rate (20 GSa/s) — is thus effective for high-throughput label-free, morphology-based cellular classification down to single-cell precision. Upon integration with the high-throughput image processing technology, this pixel-SR time-stretch imaging technique represents a cost-effective and practical solution for large scale cell-based phenotypic screening in biomedical diagnosis and machine vision for quality control in manufacturing.

A subspace approach to high-resolution spectroscopic imaging.

Science.gov (United States)

Lam, Fan; Liang, Zhi-Pei

2014-04-01

To accelerate spectroscopic imaging using sparse sampling of (k,t)-space and subspace (or low-rank) modeling to enable high-resolution metabolic imaging with good signal-to-noise ratio. The proposed method, called SPectroscopic Imaging by exploiting spatiospectral CorrElation, exploits a unique property known as partial separability of spectroscopic signals. This property indicates that high-dimensional spectroscopic signals reside in a very low-dimensional subspace and enables special data acquisition and image reconstruction strategies to be used to obtain high-resolution spatiospectral distributions with good signal-to-noise ratio. More specifically, a hybrid chemical shift imaging/echo-planar spectroscopic imaging pulse sequence is proposed for sparse sampling of (k,t)-space, and a low-rank model-based algorithm is proposed for subspace estimation and image reconstruction from sparse data with the capability to incorporate prior information and field inhomogeneity correction. The performance of the proposed method has been evaluated using both computer simulations and phantom studies, which produced very encouraging results. For two-dimensional spectroscopic imaging experiments on a metabolite phantom, a factor of 10 acceleration was achieved with a minimal loss in signal-to-noise ratio compared to the long chemical shift imaging experiments and with a significant gain in signal-to-noise ratio compared to the accelerated echo-planar spectroscopic imaging experiments. The proposed method, SPectroscopic Imaging by exploiting spatiospectral CorrElation, is able to significantly accelerate spectroscopic imaging experiments, making high-resolution metabolic imaging possible. Copyright © 2014 Wiley Periodicals, Inc.

Using IR Imaging of Water Surfaces for Estimating Piston Velocities

Science.gov (United States)

Gålfalk, M.; Bastviken, D.; Arneborg, L.

2013-12-01

The transport of gasses dissolved in surface waters across the water-atmosphere interface is controlled by the piston velocity (k). This coefficient has large implications for, e.g., greenhouse gas fluxes but is challenging to quantify in situ. At present, empirical k-wind speed relationships from a small number of studies and systems are often extrapolated without knowledge of model performance. It is therefore of interest to search for new methods for estimating k, and to compare the pros and cons of existing and new methods. Wind speeds in such models are often measured at a height of 10 meters. In smaller bodies of water such as lakes, wind speeds can vary dramatically across the surface through varying degrees of wind shadow from e.g. trees at the shoreline. More local measurements of the water surface, through wave heights or surface motion mapping, could give improved k-estimates over a surface, also taking into account wind fetch. At thermal infrared (IR) wavelengths water has very low reflectivity (depending on viewing angle) than can go below 1%, meaning that more than 99% is heat radiation giving a direct measurement of surface temperature variations. Using an IR camera at about 100 frames/s one could map surface temperature structures at a fraction of a mm depth even with waves present. In this presentation I will focus on IR imaging as a possible tool for estimating piston velocities. Results will be presented from IR field measurements, relating the motions of surface temperature structures to k calculated from other simultaneous measurements (flux chamber and ADV-Based Dissipation Rate), but also attempting to calculate k directly from the IR surface divergence. A relation between wave height and k will also be presented.

Multi-pollutants sensors based on near-IR telecom lasers and mid-IR difference frequency generation: development and applications

International Nuclear Information System (INIS)

Cousin, J.

2006-12-01

At present the detection of VOC and other anthropic trace pollutants is an important challenge in the measurement of air quality. Infrared spectroscopy, allowing spectral regions rich in molecular absorption to be probed, is a suitable technique for in-situ monitoring of the air pollution. Thus the aim of this work was to develop instruments capable of detecting multiple pollutants for in-situ monitoring by IR spectroscopy. A first project benefited from the availability of the telecommunications lasers emitting in near-IR. This instrument was based on an external cavity diode laser (1500 - 1640 nm) in conjunction with a multipass cell (100 m). The detection sensitivity was optimised by employing a balanced detection and a sweep integration procedure. The instrument developed is deployable for in-situ measurements with a sensitivity of -8 cm -1 Hz -1/2 and allowed the quantification of chemical species such as CO 2 , CO, C 2 H 2 , CH 4 and the determination of the isotopic ratio 13 CO 2 / 12 CO 2 in combustion environment The second project consisted in mixing two near-IR fiber lasers in a non-linear crystal (PPLN) in order to produce a laser radiation by difference frequency generation in the middle-IR (3.15 - 3.43 μm), where the absorption bands of the molecules are the most intense. The first studies with this source were carried out on detection of ethylene (C 2 H 4 ) and benzene (C 6 H 6 ). Developments, characterizations and applications of these instruments in the near and middle IR are detailed and the advantages of the 2 spectral ranges is highlighted. (author)

VERY LARGE INTERSTELLAR GRAINS AS EVIDENCED BY THE MID-INFRARED EXTINCTION

Energy Technology Data Exchange (ETDEWEB)

Wang, Shu; Jiang, B. W. [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Li, Aigen, E-mail: shuwang@mail.bnu.edu.cn, E-mail: bjiang@bnu.edu.cn, E-mail: wanshu@missouri.edu, E-mail: lia@missouri.edu [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States)

2015-09-20

The sizes of interstellar grains are widely distributed, ranging from a few angstroms to a few micrometers. The ultraviolet (UV) and optical extinction constrains the dust in the size range of a couple hundredths of micrometers to several submicrometers. The near and mid infrared (IR) emission constrains the nanometer-sized grains and angstrom-sized very large molecules. However, the quantity and size distribution of micrometer-sized grains remain unknown because they are gray in the UV/optical extinction and they are too cold and emit too little in the IR to be detected by IRAS, Spitzer, or Herschel. In this work, we employ the ∼3–8 μm mid-IR extinction, which is flat in both diffuse and dense regions to constrain the quantity, size, and composition of the μm-sized grain component. We find that, together with nano- and submicron-sized silicate and graphite (as well as polycyclic aromatic hydrocarbons), μm-sized graphite grains with C/H ≈ 137 ppm and a mean size of ∼1.2 μm closely fit the observed interstellar extinction of the Galactic diffuse interstellar medium from the far-UV to the mid-IR, as well as the near-IR to millimeter thermal emission obtained by COBE/DIRBE, COBE/FIRAS, and Planck up to λ ≲ 1000 μm. The μm-sized graphite component accounts for ∼14.6% of the total dust mass and ∼2.5% of the total IR emission.

A cloud mask methodology for high resolution remote sensing data combining information from high and medium resolution optical sensors

Science.gov (United States)

Sedano, Fernando; Kempeneers, Pieter; Strobl, Peter; Kucera, Jan; Vogt, Peter; Seebach, Lucia; San-Miguel-Ayanz, Jesús

2011-09-01

This study presents a novel cloud masking approach for high resolution remote sensing images in the context of land cover mapping. As an advantage to traditional methods, the approach does not rely on thermal bands and it is applicable to images from most high resolution earth observation remote sensing sensors. The methodology couples pixel-based seed identification and object-based region growing. The seed identification stage relies on pixel value comparison between high resolution images and cloud free composites at lower spatial resolution from almost simultaneously acquired dates. The methodology was tested taking SPOT4-HRVIR, SPOT5-HRG and IRS-LISS III as high resolution images and cloud free MODIS composites as reference images. The selected scenes included a wide range of cloud types and surface features. The resulting cloud masks were evaluated through visual comparison. They were also compared with ad-hoc independently generated cloud masks and with the automatic cloud cover assessment algorithm (ACCA). In general the results showed an agreement in detected clouds higher than 95% for clouds larger than 50 ha. The approach produced consistent results identifying and mapping clouds of different type and size over various land surfaces including natural vegetation, agriculture land, built-up areas, water bodies and snow.

Super-Resolution Reconstruction of Remote Sensing Images Using Multifractal Analysis

Directory of Open Access Journals (Sweden)

Mao-Gui Hu

2009-10-01

Full Text Available Satellite remote sensing (RS is an important contributor to Earth observation, providing various kinds of imagery every day, but low spatial resolution remains a critical bottleneck in a lot of applications, restricting higher spatial resolution analysis (e.g., intraurban. In this study, a multifractal-based super-resolution reconstruction method is proposed to alleviate this problem. The multifractal characteristic is common in Nature. The self-similarity or self-affinity presented in the image is useful to estimate details at larger and smaller scales than the original. We first look for the presence of multifractal characteristics in the images. Then we estimate parameters of the information transfer function and noise of the low resolution image. Finally, a noise-free, spatial resolutionenhanced image is generated by a fractal coding-based denoising and downscaling method. The empirical case shows that the reconstructed super-resolution image performs well indetail enhancement. This method is not only useful for remote sensing in investigating Earth, but also for other images with multifractal characteristics.

Subpicosecond time-resolution image converter the picochron

International Nuclear Information System (INIS)

Butslov, M.M.; Fanchenko, S.D.; Chikin, R.V.

The problem of X-band resonance ultra-high-speed electron image swept in image converters is considered. A time analysis image converter tube is described. It is provided with a circular image-sweeping system, the sweeping speed ranging from 1 up to 2 light velocities. The swept-image intensifier makes it possible to record every electron emerging from the input photocathode. The time analysis electrostatic lens provides an electronic field at the input photocathode, strong enough to obtain a high physical time resolution. The image sweeping system to be described enables one to have a 5.10 -13 s time resolution over on observation period as long as 5.10 -8 s. It requires no precise limiting with the process to observed. The picochron tube design is described together with some results of its testing in Nd-laser experiments. Transitories as short as 0.5-1psec have been detected in ultra-short laser radiation pulses

Towards sub-{Angstrom} resolution through incoherent imaging

Energy Technology Data Exchange (ETDEWEB)

Pennycook, S.J.; Chisholm, M.F. [Oak Ridge National Lab., TN (United States); Nellist, P.D. [Cavendish Lab., Cambridge, (United Kingdom)

1997-04-01

As first pointed out by Lord Rayleigh a century ago, incoherent imaging offers a substantial resolution enhancement compared to coherent imaging, together with freedom from phase contrast interference effects and contrast oscillations. In the STEM configuration, with a high angle annular detector to provide the transverse incoherence, the image also shows strong Z-contrast, sufficient in the case of a 300 kV STEM to image single Pt and Rh atoms on a {gamma}-alumina support. The annular detector provides complementarity to a bright field detector of the same size. For weakly scattering specimens, it shows greater contrast than the incoherent bright field image, and also facilitates EELS analysis at atomic resolution, using the Z-contrast image to locate the probe with sub-{angstrom} precision. The inner radius of the annular detector can be chosen to reduce the transverse coherence length to well below the spacings needed to resolve the object, a significant advantage compared to light microscopy.

Determination of carbohydrates present in Saccharomyces cerevisiae using mid-infrared spectroscopy and partial least squares regression

OpenAIRE

Plata, Maria R.; Koch, Cosima; Wechselberger, Patrick; Herwig, Christoph; Lendl, Bernhard

2013-01-01

A fast and simple method to control variations in carbohydrate composition of Saccharomyces cerevisiae, baker's yeast, during fermentation was developed using mid-infrared (mid-IR) spectroscopy. The method allows for precise and accurate determinations with minimal or no sample preparation and reagent consumption based on mid-IR spectra and partial least squares (PLS) regression. The PLS models were developed employing the results from reference analysis of the yeast cells. The reference anal...

Magnetic Resonance Super-resolution Imaging Measurement with Dictionary-optimized Sparse Learning

Directory of Open Access Journals (Sweden)

Li Jun-Bao

2017-06-01

Full Text Available Magnetic Resonance Super-resolution Imaging Measurement (MRIM is an effective way of measuring materials. MRIM has wide applications in physics, chemistry, biology, geology, medical and material science, especially in medical diagnosis. It is feasible to improve the resolution of MR imaging through increasing radiation intensity, but the high radiation intensity and the longtime of magnetic field harm the human body. Thus, in the practical applications the resolution of hardware imaging reaches the limitation of resolution. Software-based super-resolution technology is effective to improve the resolution of image. This work proposes a framework of dictionary-optimized sparse learning based MR super-resolution method. The framework is to solve the problem of sample selection for dictionary learning of sparse reconstruction. The textural complexity-based image quality representation is proposed to choose the optimal samples for dictionary learning. Comprehensive experiments show that the dictionary-optimized sparse learning improves the performance of sparse representation.

Super resolution reconstruction of infrared images based on classified dictionary learning

Science.gov (United States)

Liu, Fei; Han, Pingli; Wang, Yi; Li, Xuan; Bai, Lu; Shao, Xiaopeng

2018-05-01

Infrared images always suffer from low-resolution problems resulting from limitations of imaging devices. An economical approach to combat this problem involves reconstructing high-resolution images by reasonable methods without updating devices. Inspired by compressed sensing theory, this study presents and demonstrates a Classified Dictionary Learning method to reconstruct high-resolution infrared images. It classifies features of the samples into several reasonable clusters and trained a dictionary pair for each cluster. The optimal pair of dictionaries is chosen for each image reconstruction and therefore, more satisfactory results is achieved without the increase in computational complexity and time cost. Experiments and results demonstrated that it is a viable method for infrared images reconstruction since it improves image resolution and recovers detailed information of targets.

Towards rapid high-resolution mid-IR imaging for molecular spectral histopathological diagnosis of oesophageal cancers

DEFF Research Database (Denmark)

Hermes, M.; Nallala, J.; Huot, Laurent

2017-01-01

Modem western societies suffer from diseases of civilization which are mainly associated with smoking, fatty diets and obesity. One of those is the Gastroesophageal reflux disease (GERD) often also loosely called heartburn. GERD can in some cases lead to an abnormal change of cells (metaplasia......) in the lining of the oesophagus. This syndrome is defined as Barrett's oesophagus (BO). If the oesophagus suffers from reflux of acid (heartburn) it can protect itself by replacing the normal stratified squamous epithelium by acid resistant columnar epithelium with goblet cells usually found lower...

Mid-Latitude versus Polar-Latitude Transitional Impact Craters: Geometric Properties from Mars Orbiter Laser Altimeter (MOLA) Observations and Viking Images

Science.gov (United States)

Matias, A.; Garvin, J. B.; Sakimoto, S. E. H.

1998-01-01

One intriguing aspect of martian impact crater morphology is the change of crater cavity and ejecta characteristics from the mid-latitudes to the polar regions. This is thought to reflect differences in target properties such as an increasing presence of ice in the polar regions. Previous image-based efforts concerning martian crater morphology has documented some aspects of this, but has been hampered by the lack of adequate topography data. Recent Mars Orbiter Laser Altimeter (MOLA) topographic profiles provide a quantitative perspective for interpreting the detailed morphologies of martian crater cavities and ejecta morphology. This study is a preliminary effort to quantify the latitude-dependent differences in morphology with the goal of identifying target-dependent and crater modification effects from the combined of images and MOLA topography. We combine the available MOLA profiles and the corresponding Viking Mars Digital Image Mosaics (MDIMS), and high resolution Viking Orbiter images to focus on two transitional craters; one on the mid-latitudes, and one in the North Polar region. One MOLA pass (MGS Orbit 34) traverses the center of a 15.9 km diameter fresh complex crater located at 12.8degN 83.8degE on the Hesperian ridge plains unit (Hvr). Viking images, as well as MOLA data, show that this crater has well developed wall terraces and a central peak with 429 m of relative relief. Three MOLA passes have been acquired for a second impact crater, which is located at 69.5degN 41degE on the Vastitas Borealis Formation. This fresh rampart crater lacks terraces and central peak structures and it has a depth af 579 m. Correlation between images and MOLA topographic profiles allows us to construct basic facies maps of the craters. Eight main units were identified, four of which are common on both craters.

An Example-Based Super-Resolution Algorithm for Selfie Images

Directory of Open Access Journals (Sweden)

Jino Hans William

2016-01-01

Full Text Available A selfie is typically a self-portrait captured using the front camera of a smartphone. Most state-of-the-art smartphones are equipped with a high-resolution (HR rear camera and a low-resolution (LR front camera. As selfies are captured by front camera with limited pixel resolution, the fine details in it are explicitly missed. This paper aims to improve the resolution of selfies by exploiting the fine details in HR images captured by rear camera using an example-based super-resolution (SR algorithm. HR images captured by rear camera carry significant fine details and are used as an exemplar to train an optimal matrix-value regression (MVR operator. The MVR operator serves as an image-pair priori which learns the correspondence between the LR-HR patch-pairs and is effectively used to super-resolve LR selfie images. The proposed MVR algorithm avoids vectorization of image patch-pairs and preserves image-level information during both learning and recovering process. The proposed algorithm is evaluated for its efficiency and effectiveness both qualitatively and quantitatively with other state-of-the-art SR algorithms. The results validate that the proposed algorithm is efficient as it requires less than 3 seconds to super-resolve LR selfie and is effective as it preserves sharp details without introducing any counterfeit fine details.

Luciola Hypertelescope Space Observatory. Versatile, Upgradable High-Resolution Imaging,from Stars to Deep-Field Cosmology

Science.gov (United States)

Labeyrie, Antoine; Le Coroller, Herve; Dejonghe, Julien; Lardiere, Olivier; Aime, Claude; Dohlen, Kjetil; Mourard, Denis; Lyon, Richard; Carpenter, Kenneth G.

2008-01-01

Luciola is a large (one kilometer) "multi-aperture densified-pupil imaging interferometer", or "hypertelescope" employing many small apertures, rather than a few large ones, for obtaining direct snapshot images with a high information content. A diluted collector mirror, deployed in space as a flotilla of small mirrors, focuses a sky image which is exploited by several beam-combiner spaceships. Each contains a pupil densifier micro-lens array to avoid the diffractive spread and image attenuation caused by the small sub-apertures. The elucidation of hypertelescope imaging properties during the last decade has shown that many small apertures tend to be far more efficient, regarding the science yield, than a few large ones providing a comparable collecting area. For similar underlying physical reasons, radio-astronomy has also evolved in the direction of many-antenna systems such as the proposed Low Frequency Array having hundreds of thousands of individual receivers . With its high limiting magnitude, reaching the mv=30 limit of HST when 100 collectors of 25cm will match its collecting area, high-resolution direct imaging in multiple channels, broad spectral coverage from the 1200 Angstrom ultra-violet to the 20 micron infra-red, apodization, coronagraphic and spectroscopic capabilities, the proposed hypertelescope observatory addresses very broad and innovative science covering different areas of ESA s Cosmic Vision program. In the initial phase, a focal spacecraft covering the UV to near IR spectral range of EMCCD photon-counting cameras ( currently 200 to 1000nm), will image details on the surface of many stars, as well as their environment, including multiple stars and clusters. Spectra will be obtained for each resel. It will also image neutron star, black-hole and micro-quasar candidates, as well as active galactic nuclei, quasars, gravitational lenses, and other Cosmic Vision targets observable with the initial modest crowding limit. With subsequent upgrade

Development of Silicon-substrate Based Fabry-Perot Etalons for far-IR Astrophysics

Science.gov (United States)

Stacey, Gordon

.8 mm thick) silicon substrate and the silicon nanofabrication techniques and include the effects of (1) precisely tuned reflective surfaces, (2) very smooth mirror surfaces leading to greater cavity efficiency, (3) reduced susceptibility to vibrations due the silicon support structures, (4) reduced susceptibility to defect finesse due to reduced mounting stress, and (5) greatly improved mechanical robustness that could result in space-qualified hardware. These improvements are enabled by the combination of silicon-based technologies and our sophisticated electromagnetic modeling. The finished products have many science applications. For example, the SSB mirrors within an MCSF would convert the FORCAST or HAWC+ cameras on SOFIA into imaging spectrometers capable of widescale mapping of the mid to far-IR fine structure lines from the Galactic Center, Galactic star formation regions and external galaxies. In fact, this new etalon technology could be used in any mid to far-IR camera, converting the camera into a moderate (100 to 4000) to high resolving power (~100,000) imaging spectrometer at modest cost. A particularly interesting application could be a large format (~10 cm diameter) FPI that could deliver resolving powers in excess of 5000 for a 10 m space telescope, which might be the incarnation of the next major far-IR space mission (see NASA Cosmic Origins Newsletter, V4, No. 1, March 2015). Our program addresses NASA's Strategic goal 1: "Expand the frontiers of knowledge, capability, and opportunity in space."; Objective 1.6: "Discover how the Universe works, explore how it began and evolved, and search for life on planets around other stars,"• specifically "Technology development and demonstration."• It also addresses Strategic Goal 2 via Objective 2.4: "Advance the Nation's STEM education and workforce pipeline by working collaborative with other agencies to engage students, teachers, and faculty in NASA's missions and unique assets."•

Central Stars of Mid-Infrared Nebulae Discovered with Spitzer and WISE

Science.gov (United States)

Gvaramadze, V. V.; Kniazev, A. Y.

2017-02-01

Searches for compact mid-IR nebulae with the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE), accompanied by spectroscopic observations of central stars of these nebulae led to the discovery of many dozens of massive stars at different evolutionary stages, of which the most numerous are candidate luminous blue variables (LBVs). In this paper, we give a census of candidate and confirmed Galactic LBVs revealed with Spitzer and WISE, and present some new results of spectroscopic observations of central stars of mid-IR nebulae.

Optical system design with common aperture for mid-infrared and laser composite guidance

Science.gov (United States)

Zhang, Xuanzhi; Yang, Zijian; Sun, Ting; Yang, Huamei; Han, Kunye; Hu, Bo

2017-02-01

When the field of operation of precision strike missiles is more and more complicated, autonomous seekers will soon encounter serious difficulties, especially with regard to low signature targets and complex scenarios. So the dual-mode sensors combining an imaging sensor with a semi-active laser seeker are conceived to overcome these specific problems. Here the sensors composed a dual field of view mid-infrared thermal imaging camera and a laser range finder have the common optical aperture which produced the minization of seeker construction. The common aperture optical systems for mid-infrared and laser dual-mode guildance have been developed, which could meet the passive middle infrared high-resolution imaging and the active laser high-precision indication and ranging. The optical system had good image quality, and fulfilled the performance requirement of seeker system. The design and expected performance of such a dual-mode optical system will be discussed.

Classification of high resolution satellite images

OpenAIRE

Karlsson, Anders

2003-01-01

In this thesis the Support Vector Machine (SVM)is applied on classification of high resolution satellite images. Sveral different measures for classification, including texture mesasures, 1st order statistics, and simple contextual information were evaluated. Additionnally, the image was segmented, using an enhanced watershed method, in order to improve the classification accuracy.

Continuous-wave near-photon counting spectral imaging detector in the mid-infrared by upconversion

DEFF Research Database (Denmark)

Dam, Jeppe Seidelin; Tidemand-Lichtenberg, Peter; Pedersen, Christian

2013-01-01

is usually measured in number of electrons. The second noise source is usually referred to as dark noise, which is the background signal generated over time. Dark noise is usually measured in electrons per pixel per second. For silicon cameras certain models like EM-CCD have close to zero read noise, whereas...... high-end IR cameras have read noise of hundreds of electrons. The dark noise for infrared cameras based on semiconductor materials is also substantially higher than for silicon cameras, typical values being millions of electrons per pixel per second for cryogenically cooled cameras whereas peltier...... cooled CCD cameras have dark noise measured in fractions of electrons per pixel per second. An ideal solution thus suggest the combination of an efficient low noise image wavelength conversion system combined with low noise silicon based cameras for low noise imaging in the IR region. We discuss image...

Application of Super-Resolution Image Reconstruction to Digital Holography

Directory of Open Access Journals (Sweden)

Zhang Shuqun

2006-01-01

Full Text Available We describe a new application of super-resolution image reconstruction to digital holography which is a technique for three-dimensional information recording and reconstruction. Digital holography has suffered from the low resolution of CCD sensors, which significantly limits the size of objects that can be recorded. The existing solution to this problem is to use optics to bandlimit the object to be recorded, which can cause the loss of details. Here super-resolution image reconstruction is proposed to be applied in enhancing the spatial resolution of digital holograms. By introducing a global camera translation before sampling, a high-resolution hologram can be reconstructed from a set of undersampled hologram images. This permits the recording of larger objects and reduces the distance between the object and the hologram. Practical results from real and simulated holograms are presented to demonstrate the feasibility of the proposed technique.

Facial identification in very low-resolution images simulating prosthetic vision.

Science.gov (United States)

Chang, M H; Kim, H S; Shin, J H; Park, K S

2012-08-01

Familiar facial identification is important to blind or visually impaired patients and can be achieved using a retinal prosthesis. Nevertheless, there are limitations in delivering the facial images with a resolution sufficient to distinguish facial features, such as eyes and nose, through multichannel electrode arrays used in current visual prostheses. This study verifies the feasibility of familiar facial identification under low-resolution prosthetic vision and proposes an edge-enhancement method to deliver more visual information that is of higher quality. We first generated a contrast-enhanced image and an edge image by applying the Sobel edge detector and blocked each of them by averaging. Then, we subtracted the blocked edge image from the blocked contrast-enhanced image and produced a pixelized image imitating an array of phosphenes. Before subtraction, every gray value of the edge images was weighted as 50% (mode 2), 75% (mode 3) and 100% (mode 4). In mode 1, the facial image was blocked and pixelized with no further processing. The most successful identification was achieved with mode 3 at every resolution in terms of identification index, which covers both accuracy and correct response time. We also found that the subjects recognized a distinctive face especially more accurately and faster than the other given facial images even under low-resolution prosthetic vision. Every subject could identify familiar faces even in very low-resolution images. And the proposed edge-enhancement method seemed to contribute to intermediate-stage visual prostheses.

Super-resolution Microscopy in Plant Cell Imaging.

Science.gov (United States)

Komis, George; Šamajová, Olga; Ovečka, Miroslav; Šamaj, Jozef

2015-12-01

Although the development of super-resolution microscopy methods dates back to 1994, relevant applications in plant cell imaging only started to emerge in 2010. Since then, the principal super-resolution methods, including structured-illumination microscopy (SIM), photoactivation localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM), and stimulated emission depletion microscopy (STED), have been implemented in plant cell research. However, progress has been limited due to the challenging properties of plant material. Here we summarize the basic principles of existing super-resolution methods and provide examples of applications in plant science. The limitations imposed by the nature of plant material are reviewed and the potential for future applications in plant cell imaging is highlighted. Copyright © 2015 Elsevier Ltd. All rights reserved.

Concept of dual-resolution light field imaging using an organic photoelectric conversion film for high-resolution light field photography.

Science.gov (United States)

Sugimura, Daisuke; Kobayashi, Suguru; Hamamoto, Takayuki

2017-11-01

Light field imaging is an emerging technique that is employed to realize various applications such as multi-viewpoint imaging, focal-point changing, and depth estimation. In this paper, we propose a concept of a dual-resolution light field imaging system to synthesize super-resolved multi-viewpoint images. The key novelty of this study is the use of an organic photoelectric conversion film (OPCF), which is a device that converts spectra information of incoming light within a certain wavelength range into an electrical signal (pixel value), for light field imaging. In our imaging system, we place the OPCF having the green spectral sensitivity onto the micro-lens array of the conventional light field camera. The OPCF allows us to acquire the green spectra information only at the center viewpoint with the full resolution of the image sensor. In contrast, the optical system of the light field camera in our imaging system captures the other spectra information (red and blue) at multiple viewpoints (sub-aperture images) but with low resolution. Thus, our dual-resolution light field imaging system enables us to simultaneously capture information about the target scene at a high spatial resolution as well as the direction information of the incoming light. By exploiting these advantages of our imaging system, our proposed method enables the synthesis of full-resolution multi-viewpoint images. We perform experiments using synthetic images, and the results demonstrate that our method outperforms other previous methods.

Inherent Limitations in Mid-Wave and Long-Wave-IR Upconversion Detector

DEFF Research Database (Denmark)

Barh, Ajanta; Tseng, Yu-Pei; Pedersen, Christian

2017-01-01

Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper.......Inherent limitations in terms of optical losses, selection of nonlinear crystal(s), detection efficiency and pumping conditions in mid-wave (3-5 µm) and long-wave (8-12 µm) infrared frequency upconversion modules are investigated in this paper....

UV-BRIGHT NEARBY EARLY-TYPE GALAXIES OBSERVED IN THE MID-INFRARED: EVIDENCE FOR A MULTI-STAGE FORMATION HISTORY BY WAY OF WISE AND GALEX IMAGING

International Nuclear Information System (INIS)

Petty, S. M.; Farrah, D. G.; Neill, J. D.; Bridge, C. R.; Jarrett, T. H.; Tsai, C.-W.; Blain, A. W.; Rich, R. M.; Lake, S. E.; Wright, E. L.; Benford, D. J.; Masci, F. J.

2013-01-01

In the local universe, 10% of massive elliptical galaxies are observed to exhibit a peculiar property: a substantial excess of ultraviolet emission than what is expected from their old, red stellar populations. Several origins for this ultraviolet excess (UVX) have been proposed including a population of hot young stars and a population of old, blue horizontal branch or extended horizontal branch (BHB or EHB) stars that have undergone substantial mass loss from their outer atmospheres. We explore the radial distribution of UVX in a selection of 49 nearby E/S0-type galaxies by measuring their extended photometry in the UV through mid-infrared (mid-IR) with the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the Wide-field Infrared Survey Explorer (WISE). We compare UV/optical and UV/mid-IR colors with the Flexible Stellar Population Synthesis models, which allow for the inclusion of EHB stars. We find that combined WISE mid-IR and GALEX UV colors are more effective in distinguishing models than optical colors, and that the UV/mid-IR combination is sensitive to the EHB fraction. There are strong color gradients, with the outer radii bluer than the inner half-light radii by ∼1 mag. This color difference is easily accounted for with an increase in the BHB fraction of 0.25 with radius. We estimated that the average ages for the inner and outer radii are 7.0 ± 0.3 Gyr, and 6.2 ± 0.2 Gyr, respectively, with the implication that the outer regions are likely to have formed ∼1 Gyr after the inner regions. Additionally, we find that metallicity gradients are likely not a significant factor in the color difference. The separation of color between the inner and outer regions, which agrees with a specific stellar population difference (e.g., higher EHB populations), and the ∼0.5-2 Gyr age difference suggests multi-stage formation. Our results are best explained by inside-out formation: rapid star formation within the core at early epochs (>4 Gyr ago

UV-BRIGHT NEARBY EARLY-TYPE GALAXIES OBSERVED IN THE MID-INFRARED: EVIDENCE FOR A MULTI-STAGE FORMATION HISTORY BY WAY OF WISE AND GALEX IMAGING

Energy Technology Data Exchange (ETDEWEB)

Petty, S. M.; Farrah, D. G. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Neill, J. D.; Bridge, C. R. [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Jarrett, T. H.; Tsai, C.-W. [Astronomy Department, University of Cape Town, Rondebosch 7701 (South Africa); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Rich, R. M.; Lake, S. E.; Wright, E. L. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Benford, D. J. [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Masci, F. J. [IPAC, California Institute of Technology, Pasadena, CA 91125 (United States)

2013-10-01

In the local universe, 10% of massive elliptical galaxies are observed to exhibit a peculiar property: a substantial excess of ultraviolet emission than what is expected from their old, red stellar populations. Several origins for this ultraviolet excess (UVX) have been proposed including a population of hot young stars and a population of old, blue horizontal branch or extended horizontal branch (BHB or EHB) stars that have undergone substantial mass loss from their outer atmospheres. We explore the radial distribution of UVX in a selection of 49 nearby E/S0-type galaxies by measuring their extended photometry in the UV through mid-infrared (mid-IR) with the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the Wide-field Infrared Survey Explorer (WISE). We compare UV/optical and UV/mid-IR colors with the Flexible Stellar Population Synthesis models, which allow for the inclusion of EHB stars. We find that combined WISE mid-IR and GALEX UV colors are more effective in distinguishing models than optical colors, and that the UV/mid-IR combination is sensitive to the EHB fraction. There are strong color gradients, with the outer radii bluer than the inner half-light radii by {approx}1 mag. This color difference is easily accounted for with an increase in the BHB fraction of 0.25 with radius. We estimated that the average ages for the inner and outer radii are 7.0 {+-} 0.3 Gyr, and 6.2 {+-} 0.2 Gyr, respectively, with the implication that the outer regions are likely to have formed {approx}1 Gyr after the inner regions. Additionally, we find that metallicity gradients are likely not a significant factor in the color difference. The separation of color between the inner and outer regions, which agrees with a specific stellar population difference (e.g., higher EHB populations), and the {approx}0.5-2 Gyr age difference suggests multi-stage formation. Our results are best explained by inside-out formation: rapid star formation within the core at early

Uv-bright Nearby Early-type Galaxies Observed in the Mid-infrared: Eidence for a Multi-stage Formation History by Way of WISE and GALEX Imaging

Science.gov (United States)

Petty, S. M.; Neill, J. D.; Jarrett, T. H.; Blain, A. W.; Farrah, D. G.; Rich, R. M.; Tsai, C.-W.; Benford, D. J.; Bridge, C. R.; Lake, S. E.;

Urban Shanty Town Recognition Based on High-Resolution Remote Sensing Images and National Geographical Monitoring Features - a Case Study of Nanning City

Science.gov (United States)

He, Y.; He, Y.

2018-04-01

Urban shanty towns are communities that has contiguous old and dilapidated houses with more than 2000 square meters built-up area or more than 50 households. This study makes attempts to extract shanty towns in Nanning City using the product of Census and TripleSat satellite images. With 0.8-meter high-resolution remote sensing images, five texture characteristics (energy, contrast, maximum probability, and inverse difference moment) of shanty towns are trained and analyzed through GLCM. In this study, samples of shanty town are well classified with 98.2 % producer accuracy of unsupervised classification and 73.2 % supervised classification correctness. Low-rise and mid-rise residential blocks in Nanning City are classified into 4 different types by using k-means clustering and nearest neighbour classification respectively. This study initially establish texture feature descriptions of different types of residential areas, especially low-rise and mid-rise buildings, which would help city administrator evaluate residential blocks and reconstruction shanty towns.

Image resolution influence on determination of resin injection rock mass

Science.gov (United States)

Wang, Weixing; Hakami, Eva

2006-01-01

In the context of nuclear waste repositories, an important approach to understanding brittle rock mass behavior to integrate new and powerful observational and numerical methods with multi-functional 3-D imaging and visualization techniques. Since 1994, Swedish Nuclear Fuel and Waste Management Company (SKB) have identified the need for a better understanding of radionuclide transport and retention processes in fractured rock. As a cooperation project between Sweden and China, we sampled a number of rock specimens for analyze rock fracture network by optical image technique. The samples are resin injected, in which way; opened fractures can be seen clearly by means of UV (Ultraviolet) light illumination. In the study period, we used different optical focuses to obtain the images from the same samples; we found that Image resolution influences on porosity determination of resin injected rock mass. This paper presents and discusses the six issues based on our research results: (1) Fracture porosity increases as camera focus distance decreases; (2) Porosity increases as illumination increases in resin injected fracture images; (3) To roughly estimate the porosity, the low resolution image can be used; (4) To collect more details of fracture information, the high resolution image is needed; (5) The resolution of image should be determined based on the aim of fracture analysis; (6) To acquire high resolution image, constructing a special illumination (standard) box maybe helpful to avoid light reflection and diffusion.

Young massive stars and their environment in the mid-infrared at high angular resolution

International Nuclear Information System (INIS)

Wit, W J de; Hoare, M G; Oudmaijer, R D; Fujiyoshi, T

2008-01-01

We present interferometric and single-dish mid-infrared observations of a sample of massive young stellar objects (BN-type objects), using VLTI-MIDI (10μm) and Subaru-COMICS (24.5 μm). We discuss the regions S140, Mon R2, M8E-IR, and W33A. The observations probe the inner regions of the dusty envelope at scales of 50 milli arcsecond and 0.6'' (∼100-1000 AU), respectively. Simultaneous model fits to spectral energy distributions and spatial data are achieved using self-consistent spherical envelope modelling. We conclude that those MYSO envelopes that are best described by a spherical geometry, the commensurate density distribution is a powerlaw with index -1.0. Such a powerlaw is predicted if the envelope is supported by turbulence on the 100-1000 AU scales probed with MIDI and COMICS, but the role of rotation at these spatial scales need testing.

Fundamental limits to imaging resolution for focused ion beams

International Nuclear Information System (INIS)

Orloff, J.; Swanson, L.W.; Utlaut, M.

1996-01-01

This article investigates the limitations on the formation of focused ion beam images from secondary electrons. We use the notion of the information content of an image to account for the effects of resolution, contrast, and signal-to-noise ratio and show that there is a competition between the rate at which small features are sputtered away by the primary beam and the rate of collection of secondary electrons. We find that for small features, sputtering is the limit to imaging resolution, and that for extended small features (e.g., layered structures), rearrangement, redeposition, and differential sputtering rates may limit the resolution in some cases. copyright 1996 American Vacuum Society

Speckle correlation resolution enhancement of wide-field fluorescence imaging (Conference Presentation)

Science.gov (United States)

Yilmaz, Hasan

2016-03-01

Structured illumination enables high-resolution fluorescence imaging of nanostructures [1]. We demonstrate a new high-resolution fluorescence imaging method that uses a scattering layer with a high-index substrate as a solid immersion lens [2]. Random scattering of coherent light enables a speckle pattern with a very fine structure that illuminates the fluorescent nanospheres on the back surface of the high-index substrate. The speckle pattern is raster-scanned over the fluorescent nanospheres using a speckle correlation effect known as the optical memory effect. A series of standard-resolution fluorescence images per each speckle pattern displacement are recorded by an electron-multiplying CCD camera using a commercial microscope objective. We have developed a new phase-retrieval algorithm to reconstruct a high-resolution, wide-field image from several standard-resolution wide-field images. We have introduced phase information of Fourier components of standard-resolution images as a new constraint in our algorithm which discards ambiguities therefore ensures convergence to a unique solution. We demonstrate two-dimensional fluorescence images of a collection of nanospheres with a deconvolved Abbe resolution of 116 nm and a field of view of 10 µm × 10 µm. Our method is robust against optical aberrations and stage drifts, therefore excellent for imaging nanostructures under ambient conditions. [1] M. G. L. Gustafsson, J. Microsc. 198, 82-87 (2000). [2] H. Yilmaz, E. G. van Putten, J. Bertolotti, A. Lagendijk, W. L. Vos, and A. P. Mosk, Optica 2, 424-429 (2015).

Effects of Resolution, Range, and Image Contrast on Target Acquisition Performance.

Science.gov (United States)

Hollands, Justin G; Terhaar, Phil; Pavlovic, Nada J

2018-05-01

We sought to determine the joint influence of resolution, target range, and image contrast on the detection and identification of targets in simulated naturalistic scenes. Resolution requirements for target acquisition have been developed based on threshold values obtained using imaging systems, when target range was fixed, and image characteristics were determined by the system. Subsequent work has examined the influence of factors like target range and image contrast on target acquisition. We varied the resolution and contrast of static images in two experiments. Participants (soldiers) decided whether a human target was located in the scene (detection task) or whether a target was friendly or hostile (identification task). Target range was also varied (50-400 m). In Experiment 1, 30 participants saw color images with a single target exemplar. In Experiment 2, another 30 participants saw monochrome images containing different target exemplars. The effects of target range and image contrast were qualitatively different above and below 6 pixels per meter of target for both tasks in both experiments. Target detection and identification performance were a joint function of image resolution, range, and contrast for both color and monochrome images. The beneficial effects of increasing resolution for target acquisition performance are greater for closer (larger) targets.

Regions of mid-level human visual cortex sensitive to the global coherence of local image patches.

Science.gov (United States)

Mannion, Damien J; Kersten, Daniel J; Olman, Cheryl A

2014-08-01

The global structural arrangement and spatial layout of the visual environment must be derived from the integration of local signals represented in the lower tiers of the visual system. This interaction between the spatially local and global properties of visual stimulation underlies many of our visual capacities, and how this is achieved in the brain is a central question for visual and cognitive neuroscience. Here, we examine the sensitivity of regions of the posterior human brain to the global coordination of spatially displaced naturalistic image patches. We presented observers with image patches in two circular apertures to the left and right of central fixation, with the patches drawn from either the same (coherent condition) or different (noncoherent condition) extended image. Using fMRI at 7T (n = 5), we find that global coherence affected signal amplitude in regions of dorsal mid-level cortex. Furthermore, we find that extensive regions of mid-level visual cortex contained information in their local activity pattern that could discriminate coherent and noncoherent stimuli. These findings indicate that the global coordination of local naturalistic image information has important consequences for the processing in human mid-level visual cortex.

Low-noise mid-IR upconversion detector for improved IR-degenerate four-wave mixing gas sensing

DEFF Research Database (Denmark)

Høgstedt, Lasse; Dam, Jeppe Seidelin; Sahlberg, Anna-Lena

2014-01-01

-to-noise ratio. The two detectors are compared for the detection of a coherent degenerate four-wave mixing (DFWM) signal in the mid-infrared, and applied to measure trace-level acetylene in a gas flow at atmospheric pressure, probing its fundamental rovibrational transitions. In addition to lower noise...

Subspace-Based Holistic Registration for Low-Resolution Facial Images

Directory of Open Access Journals (Sweden)

Boom BJ

2010-01-01

Full Text Available Subspace-based holistic registration is introduced as an alternative to landmark-based face registration, which has a poor performance on low-resolution images, as obtained in camera surveillance applications. The proposed registration method finds the alignment by maximizing the similarity score between a probe and a gallery image. We use a novel probabilistic framework for both user-independent as well as user-specific face registration. The similarity is calculated using the probability that the face image is correctly aligned in a face subspace, but additionally we take the probability into account that the face is misaligned based on the residual error in the dimensions perpendicular to the face subspace. We perform extensive experiments on the FRGCv2 database to evaluate the impact that the face registration methods have on face recognition. Subspace-based holistic registration on low-resolution images can improve face recognition in comparison with landmark-based registration on high-resolution images. The performance of the tested face recognition methods after subspace-based holistic registration on a low-resolution version of the FRGC database is similar to that after manual registration.

A MID-INFRARED VIEW OF THE HIGH MASS STAR FORMATION REGION W51A

Energy Technology Data Exchange (ETDEWEB)

Barbosa, C. L. [Laboratório Nacional de Astrofísica, R. dos Estados Unidos, Bairro das Nações, CEP 37504-364, Itajubá—MG (Brazil); Blum, R. D. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Damineli, A. [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, R. do Matão, 1226, Cid. Universitária, São Paulo 05508-900 (Brazil); Conti, P. S. [JILA, University of Colorado, Boulder, CO 80309-0440 (United States); Gusmão, D. M., E-mail: cassio.barbosa@pq.cnpq.br, E-mail: rblum@noao.edu, E-mail: augusto.damineli@iag.usp.br, E-mail: pconti@jila.colorado.edu, E-mail: danilo@univap.br [IP and D—Universidade do Vale do Paraíba, Av. Shishima Hifumi, 2911. São José dos Campos, SP, 12244-000 (Brazil)

2016-07-01

In this paper we present the results of a mid-infrared study of G49.5-0.4, or W51A, part of the massive starbirth complex W51. Combining public data from the Spitzer IRAC camera, and Gemini mid-infrared camera T-ReCS at 7.73, 9.69, 12.33, and 24.56 μ m, with a spatial resolution of ∼0.″5, we have identified the mid-infrared counterparts of eight ultracompact H ii regions, showing that two radio sources are deeply embedded in molecular clouds and another is a cloud of ionized gas. From the T-ReCS data we have unveiled the central core of the W51 region, revealing massive young stellar candidates. We modeled the spectral energy distribution of the detected sources. The results suggest that the embedded objects are sources with spectral types ranging from B3 to O5, but the majority of the fits indicate stellar objects with B1 spectral types. We also present an extinction map of IRS 2, showing that a region with lower extinction corresponds to the region where a proposed jet of gas has impacted the foreground cloud. From this map, we also derived the total extinction toward the enigmatic source IRS 2E, which amounts to ∼60 mag in the V band. We calculated the color temperature due to thermal emission of the circumstellar dust of the detected sources; the temperatures are in the interval of ∼100–150 K, which corresponds to the emission of dust located at 0.1 pc from the central source. Finally, we show a possible mid-infrared counterpart of a detected source at millimeter wavelengths that was found by Zapata et al. to be a massive young stellar object undergoing a high accretion rate.

Multisensor Super Resolution Using Directionally-Adaptive Regularization for UAV Images.

Science.gov (United States)

Kang, Wonseok; Yu, Soohwan; Ko, Seungyong; Paik, Joonki

2015-05-22

In various unmanned aerial vehicle (UAV) imaging applications, the multisensor super-resolution (SR) technique has become a chronic problem and attracted increasing attention. Multisensor SR algorithms utilize multispectral low-resolution (LR) images to make a higher resolution (HR) image to improve the performance of the UAV imaging system. The primary objective of the paper is to develop a multisensor SR method based on the existing multispectral imaging framework instead of using additional sensors. In order to restore image details without noise amplification or unnatural post-processing artifacts, this paper presents an improved regularized SR algorithm by combining the directionally-adaptive constraints and multiscale non-local means (NLM) filter. As a result, the proposed method can overcome the physical limitation of multispectral sensors by estimating the color HR image from a set of multispectral LR images using intensity-hue-saturation (IHS) image fusion. Experimental results show that the proposed method provides better SR results than existing state-of-the-art SR methods in the sense of objective measures.

Effect of exposure time and image resolution on fractal dimension

International Nuclear Information System (INIS)

An, Byung Mo; Heo, Min Suk; Lee, Seung Pyo; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won; Kim, Jong Dae

2002-01-01

To evaluate the effect of exposure time and image resolution on fractal dimension calculations for determining the optimal range of these two variances. Thirty-one radiographs of the mandibular angle area of sixteen human dry mandibles were taken at different exposure times (0.01, 0.08, 0.16, 0.25, 0.40, 0.64, and 0.80 s). Each radiograph was digitized at 1200 dpi, 8 bit, 256 gray level using a film scanner. We selected an Region of Interest (ROI) that corresponded to the same region as in each radiograph, but the resolution of ROI was degraded to 1000, 800, 600, 500, 400, 300, 200, and 100 dpi. The fractal dimension was calculated by using the tile-counting method for each image, and the calculated values were then compared statistically. As the exposure time and the image resolution increased, the mean value of the fractal dimension decreased, except the case where exposure time was set at 0.01 seconds (alpha = 0.05). The exposure time and image resolution affected the fractal dimension by interaction (p<0.001). When the exposure time was set to either 0.64 seconds or 0.80 seconds, the resulting fractal dimensions were lower, irrespective of image resolution, than at shorter exposure times (alpha = 0.05). The optimal range for exposure time and resolution was determined to be 0.08-0.40 seconds and from 400-1000 dpi, respectively. Adequate exposure time and image resolution is essential for acquiring the fractal dimension using tile-counting method for evaluation of the mandible.

Enhancing the sensitivity of mid-IR quantum cascade laser-based cavity-enhanced absorption spectroscopy using RF current perturbation.

Science.gov (United States)

Manfred, Katherine M; Kirkbride, James M R; Ciaffoni, Luca; Peverall, Robert; Ritchie, Grant A D

2014-12-15

The sensitivity of mid-IR quantum cascade laser (QCL) off-axis cavity-enhanced absorption spectroscopy (CEAS), often limited by cavity mode structure and diffraction losses, was enhanced by applying a broadband RF noise to the laser current. A pump-probe measurement demonstrated that the addition of bandwidth-limited white noise effectively increased the laser linewidth, thereby reducing mode structure associated with CEAS. The broadband noise source offers a more sensitive, more robust alternative to applying single-frequency noise to the laser. Analysis of CEAS measurements of a CO(2) absorption feature at 1890  cm(-1) averaged over 100 ms yielded a minimum detectable absorption of 5.5×10(-3)  Hz(-1/2) in the presence of broadband RF perturbation, nearly a tenfold improvement over the unperturbed regime. The short acquisition time makes this technique suitable for breath applications requiring breath-by-breath gas concentration information.

Effects of scanning resolution and digital image magnification on photostimulable phosphor imaging system

International Nuclear Information System (INIS)

Sakurai, Takashi; Inagaki, Masafumi; Asai, Hideomi; Koyama, Atsushi; Kashima, Isamu

2000-01-01

The purpose of this study is to examine the effects of changes in scanning resolution and digital magnification on the image quality and diagnostic ability of the photostimulable phosphor imaging system. Using a photostimulable phosphor imaging system, images of a human adult dried mandible phantom embedded in a 25 mm-thick epoxy resin block were made. The latent images on the photostimulable phosphor imaging plate were scanned using four different pixel sizes as follows: 25 μm x 25 μm, 50 μm x 50 μm, 100 μm x 100 μm and 200 μm x 200 μm. A primary image was produced for each pixel size. These images were also digitally magnified at powers of 2, 4 and 8 times. The gradient range, brightness and contrast of each image were adjusted to optimum levels on a cathode ray tube display, and hard copies were produced with a writing pixel size of 60 μm x 60 μm. The granularity, sharpness and anatomical diagnostic ability of the images were assessed subjectively by eight dentists. Increasing the scanning resolution tended to generally improve image quality and diagnostic ability. Visual image quality was maintained up to a pixel size of 50 μm, and diagnostic ability was maintained up to a pixel size of 100 μm. Digital image magnification degraded image quality, and more than 2-times magnification degraded diagnostic ability. Under the present experimental conditions, increasing the scanning resolution did not always lead to an improvement in image quality or diagnostic ability, and digital image magnification degraded image quality and diagnostic ability. (author)

Lensless high-resolution photoacoustic imaging scanner for in vivo skin imaging

Science.gov (United States)

Ida, Taiichiro; Iwazaki, Hideaki; Omuro, Toshiyuki; Kawaguchi, Yasushi; Tsunoi, Yasuyuki; Kawauchi, Satoko; Sato, Shunichi

2018-02-01

We previously launched a high-resolution photoacoustic (PA) imaging scanner based on a unique lensless design for in vivo skin imaging. The design, imaging algorithm and characteristics of the system are described in this paper. Neither an optical lens nor an acoustic lens is used in the system. In the imaging head, four sensor elements are arranged quadrilaterally, and by checking the phase differences for PA waves detected with these four sensors, a set of PA signals only originating from a chromophore located on the sensor center axis is extracted for constructing an image. A phantom study using a carbon fiber showed a depth-independent horizontal resolution of 84.0 ± 3.5 µm, and the scan direction-dependent variation of PA signals was about ± 20%. We then performed imaging of vasculature phantoms: patterns of red ink lines with widths of 100 or 200 μm formed in an acrylic block co-polymer. The patterns were visualized with high contrast, showing the capability for imaging arterioles and venues in the skin. Vasculatures in rat burn models and healthy human skin were also clearly visualized in vivo.

An integral design strategy combining optical system and image processing to obtain high resolution images

Science.gov (United States)

Wang, Jiaoyang; Wang, Lin; Yang, Ying; Gong, Rui; Shao, Xiaopeng; Liang, Chao; Xu, Jun

2016-05-01

In this paper, an integral design that combines optical system with image processing is introduced to obtain high resolution images, and the performance is evaluated and demonstrated. Traditional imaging methods often separate the two technical procedures of optical system design and imaging processing, resulting in the failures in efficient cooperation between the optical and digital elements. Therefore, an innovative approach is presented to combine the merit function during optical design together with the constraint conditions of image processing algorithms. Specifically, an optical imaging system with low resolution is designed to collect the image signals which are indispensable for imaging processing, while the ultimate goal is to obtain high resolution images from the final system. In order to optimize the global performance, the optimization function of ZEMAX software is utilized and the number of optimization cycles is controlled. Then Wiener filter algorithm is adopted to process the image simulation and mean squared error (MSE) is taken as evaluation criterion. The results show that, although the optical figures of merit for the optical imaging systems is not the best, it can provide image signals that are more suitable for image processing. In conclusion. The integral design of optical system and image processing can search out the overall optimal solution which is missed by the traditional design methods. Especially, when designing some complex optical system, this integral design strategy has obvious advantages to simplify structure and reduce cost, as well as to gain high resolution images simultaneously, which has a promising perspective of industrial application.

Initial phantom study comparing image quality in computed tomography using adaptive statistical iterative reconstruction and new adaptive statistical iterative reconstruction v.

Science.gov (United States)

Lim, Kyungjae; Kwon, Heejin; Cho, Jinhan; Oh, Jongyoung; Yoon, Seongkuk; Kang, Myungjin; Ha, Dongho; Lee, Jinhwa; Kang, Eunju

2015-01-01

The purpose of this study was to assess the image quality of a novel advanced iterative reconstruction (IR) method called as "adaptive statistical IR V" (ASIR-V) by comparing the image noise, contrast-to-noise ratio (CNR), and spatial resolution from those of filtered back projection (FBP) and adaptive statistical IR (ASIR) on computed tomography (CT) phantom image. We performed CT scans at 5 different tube currents (50, 70, 100, 150, and 200 mA) using 3 types of CT phantoms. Scanned images were subsequently reconstructed in 7 different scan settings, such as FBP, and 3 levels of ASIR and ASIR-V (30%, 50%, and 70%). The image noise was measured in the first study using body phantom. The CNR was measured in the second study using contrast phantom and the spatial resolutions were measured in the third study using a high-resolution phantom. We compared the image noise, CNR, and spatial resolution among the 7 reconstructed image scan settings to determine whether noise reduction, high CNR, and high spatial resolution could be achieved at ASIR-V. At quantitative analysis of the first and second studies, it showed that the images reconstructed using ASIR-V had reduced image noise and improved CNR compared with those of FBP and ASIR (P ASIR-V had significantly improved spatial resolution than those of FBP and ASIR (P ASIR-V provides a significant reduction in image noise and a significant improvement in CNR as well as spatial resolution. Therefore, this technique has the potential to reduce the radiation dose further without compromising image quality.

Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers

Energy Technology Data Exchange (ETDEWEB)

Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

2009-12-16

Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

Large-Scale Multi-Resolution Representations for Accurate Interactive Image and Volume Operations

KAUST Repository

Sicat, Ronell B.

2015-11-25

The resolutions of acquired image and volume data are ever increasing. However, the resolutions of commodity display devices remain limited. This leads to an increasing gap between data and display resolutions. To bridge this gap, the standard approach is to employ output-sensitive operations on multi-resolution data representations. Output-sensitive operations facilitate interactive applications since their required computations are proportional only to the size of the data that is visible, i.e., the output, and not the full size of the input. Multi-resolution representations, such as image mipmaps, and volume octrees, are crucial in providing these operations direct access to any subset of the data at any resolution corresponding to the output. Despite its widespread use, this standard approach has some shortcomings in three important application areas, namely non-linear image operations, multi-resolution volume rendering, and large-scale image exploration. This dissertation presents new multi-resolution representations for large-scale images and volumes that address these shortcomings. Standard multi-resolution representations require low-pass pre-filtering for anti- aliasing. However, linear pre-filters do not commute with non-linear operations. This becomes problematic when applying non-linear operations directly to any coarse resolution levels in standard representations. Particularly, this leads to inaccurate output when applying non-linear image operations, e.g., color mapping and detail-aware filters, to multi-resolution images. Similarly, in multi-resolution volume rendering, this leads to inconsistency artifacts which manifest as erroneous differences in rendering outputs across resolution levels. To address these issues, we introduce the sparse pdf maps and sparse pdf volumes representations for large-scale images and volumes, respectively. These representations sparsely encode continuous probability density functions (pdfs) of multi-resolution pixel

Food Image Recognition via Superpixel Based Low-Level and Mid-Level Distance Coding for Smart Home Applications

Directory of Open Access Journals (Sweden)

Jiannan Zheng

2017-05-01

Full Text Available Food image recognition is a key enabler for many smart home applications such as smart kitchen and smart personal nutrition log. In order to improve living experience and life quality, smart home systems collect valuable insights of users’ preferences, nutrition intake and health conditions via accurate and robust food image recognition. In addition, efficiency is also a major concern since many smart home applications are deployed on mobile devices where high-end GPUs are not available. In this paper, we investigate compact and efficient food image recognition methods, namely low-level and mid-level approaches. Considering the real application scenario where only limited and noisy data are available, we first proposed a superpixel based Linear Distance Coding (LDC framework where distinctive low-level food image features are extracted to improve performance. On a challenging small food image dataset where only 12 training images are available per category, our framework has shown superior performance in both accuracy and robustness. In addition, to better model deformable food part distribution, we extend LDC’s feature-to-class distance idea and propose a mid-level superpixel food parts-to-class distance mining framework. The proposed framework show superior performance on a benchmark food image datasets compared to other low-level and mid-level approaches in the literature.

Protoplanetary disks around intermediate-mass stars: the asset of imaging in the mid-infrared

International Nuclear Information System (INIS)

Doucet, Coralie

2006-01-01

The accrued efficiency of the instruments in many wavelengths has allowed to show that most young stellar objects were surrounded by circumstellar matter distributed in a disk. Direct imaging of such systems is very difficult because of their narrow angular size and their weak luminosity in comparison with the star. Nowadays, 50 % of low-mass pre-main sequence stars, i.e. T Tauri stars, are surrounded by a disk. This proportion is less obvious for intermediate-mass stars, like Herbig Ae stars, that are less numerous and whose direct disk detection is more difficult. Until now, only the interpretation of the Spectral Energy Distribution (SED) of such objects allows to have access to the geometry of the disk. But the solutions are degenerated and several parameters fit the same SED. It is essential to have direct images of the objects, the only evidence of the presence of disks. This PhD allows to show that mid-infrared imaging could rise a part of the degeneracy of the disk's parameters linked to the fit of the SED for several objects and gives constraints on the minimum external radius and inclination of the disk. We present a new observation mode with VISIR, the mid-infrared imager and spectrometer on the VLT (ESO, Chile): the so-called BURST mode. This mode allows to reach the diffraction limit of the telescope. Thanks to mid-infrared imaging with this instrument, we were able, for the first time, to have access to the geometry of a disk (flared structure) around a massive star that was, until now, only deduced from the SED modelling. (author) [fr

Effect of preservatives on the accuracy of mid-infrared milk component testing.

Science.gov (United States)

Barbano, D M; Wojciechowski, K L; Lynch, J M

2010-12-01

Our objective was to determine the effect of commonly used milk preservatives on the accuracy of fat, protein, and lactose content determination in milk by mid-infrared (mid-IR) milk analysis. Two producer raw milks (Holstein and Jersey) and 2 pasteurized modified milks, 1 similar to Holstein milk and 1 similar to Jersey milk were used as the 4 different milk sources. Seven different milk preservative approaches (K(2)Cr(2)O(7) and 6 different bronopol-based preservatives) and a portion of unpreserved milk for each of the 4 different milks sources were tested for fat B, lactose, protein, and fat A. The experiment was replicated 3 times (28 d each) for a total of 84 d. Two mid-infrared (mid-IR) transmittance milk analyzers (an optical and a virtual filter instrument) were used. A large batch of pilot milk was prepared from pasteurized, homogenized, unpreserved whole milk, split into vials, quick frozen by immersion in liquid nitrogen, and transferred into a -80 °C freezer. Pilots were thawed and analyzed on each testing day during the study. Significant increases were observed in all uncorrected readings on the pilot milks over the 84 d of the study, but the increases were gradual and small on each instrument for all components. Results from the study were corrected for these changes. A significant difference in mid-IR fat A readings was observed, whereas no differences were detected for fat B, lactose, or protein between unpreserved and preserved milks containing 0.02% K(2)Cr(2)O(7.) Therefore, K(2)Cr(2)O(7) has little or no effect on mid-IR test results. All bronopol-based preservative approaches in this study differed in mid-IR test results compared with K(2)Cr(2)O(7)-preserved and unpreserved milks, with the largest effect on protein results. Mid-IR uncorrected readings increased with time of refrigerated storage at 4°C for all preservative approaches, with the largest increase for protein. The rate of increase in uncorrected readings with time of storage was

Droplet Image Super Resolution Based on Sparse Representation and Kernel Regression

Science.gov (United States)

Zou, Zhenzhen; Luo, Xinghong; Yu, Qiang

2018-05-01

Microgravity and containerless conditions, which are produced via electrostatic levitation combined with a drop tube, are important when studying the intrinsic properties of new metastable materials. Generally, temperature and image sensors can be used to measure the changes of sample temperature, morphology and volume. Then, the specific heat, surface tension, viscosity changes and sample density can be obtained. Considering that the falling speed of the material sample droplet is approximately 31.3 m/s when it reaches the bottom of a 50-meter-high drop tube, a high-speed camera with a collection rate of up to 106 frames/s is required to image the falling droplet. However, at the high-speed mode, very few pixels, approximately 48-120, will be obtained in each exposure time, which results in low image quality. Super-resolution image reconstruction is an algorithm that provides finer details than the sampling grid of a given imaging device by increasing the number of pixels per unit area in the image. In this work, we demonstrate the application of single image-resolution reconstruction in the microgravity and electrostatic levitation for the first time. Here, using the image super-resolution method based on sparse representation, a low-resolution droplet image can be reconstructed. Employed Yang's related dictionary model, high- and low-resolution image patches were combined with dictionary training, and high- and low-resolution-related dictionaries were obtained. The online double-sparse dictionary training algorithm was used in the study of related dictionaries and overcome the shortcomings of the traditional training algorithm with small image patch. During the stage of image reconstruction, the algorithm of kernel regression is added, which effectively overcomes the shortcomings of the Yang image's edge blurs.

Fabrication and characterization of a water-free mid-infrared fluorotellurite glass.

Science.gov (United States)

Lin, Aoxiang; Ryasnyanskiy, Aleksandr; Toulouse, Jean

2011-03-01

Using a physical and chemical dehydration technique and a high-pressure, ultradry O2 atmosphere in a semiclosed steel-chamber furnace, we fabricated a group of fluorotellurite glasses with a composition of (90-x)TeO2-xZnF2-10Na2O (mol.%, x=0-30). For x=30, no OH absorption was observed in the range of 0.38-6.1 μm. This is the first report of a water-free mid-IR fluorotellurite glass, to our knowledge, offering the common advantages of a robust oxide glass and an IR-transparent fluoride one. Besides optimized linear transmittance and absorption, the nonlinear refractive indices and Raman gain coefficients are reduced. These results are discussed in the context of mid-IR high-power laser generation and transmission.

Smartphone microendoscopy for high resolution fluorescence imaging

Directory of Open Access Journals (Sweden)

Xiangqian Hong

2016-09-01

Full Text Available High resolution optical endoscopes are increasingly used in diagnosis of various medical conditions of internal organs, such as the cervix and gastrointestinal (GI tracts, but they are too expensive for use in resource-poor settings. On the other hand, smartphones with high resolution cameras and Internet access have become more affordable, enabling them to diffuse into most rural areas and developing countries in the past decade. In this paper, we describe a smartphone microendoscope that can take fluorescence images with a spatial resolution of 3.1 μm. Images collected from ex vivo, in vitro and in vivo samples using the device are also presented. The compact and cost-effective smartphone microendoscope may be envisaged as a powerful tool for detecting pre-cancerous lesions of internal organs in low and middle-income countries (LMICs.

Single-Image Super-Resolution Based on Rational Fractal Interpolation.

Science.gov (United States)

Zhang, Yunfeng; Fan, Qinglan; Bao, Fangxun; Liu, Yifang; Zhang, Caiming

2018-08-01

This paper presents a novel single-image super-resolution (SR) procedure, which upscales a given low-resolution (LR) input image to a high-resolution image while preserving the textural and structural information. First, we construct a new type of bivariate rational fractal interpolation model and investigate its analytical properties. This model has different forms of expression with various values of the scaling factors and shape parameters; thus, it can be employed to better describe image features than current interpolation schemes. Furthermore, this model combines the advantages of rational interpolation and fractal interpolation, and its effectiveness is validated through theoretical analysis. Second, we develop a single-image SR algorithm based on the proposed model. The LR input image is divided into texture and non-texture regions, and then, the image is interpolated according to the characteristics of the local structure. Specifically, in the texture region, the scaling factor calculation is the critical step. We present a method to accurately calculate scaling factors based on local fractal analysis. Extensive experiments and comparisons with the other state-of-the-art methods show that our algorithm achieves competitive performance, with finer details and sharper edges.

About possibility of temperature trace observing on the human skin using commercially available IR camera

Science.gov (United States)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Shestakov, Ivan L.; Blednov, Roman G.

2016-09-01

One of urgent security problems is a detection of objects placed inside the human body. Obviously, for safety reasons one cannot use X-rays for such object detection widely and often. Three years ago, we have demonstrated principal possibility to see a temperature trace, induced by food eating or water drinking, on the human body skin by using a passive THz camera. However, this camera is very expensive. Therefore, for practice it will be very convenient if one can use the IR camera for this purpose. In contrast to passive THz camera using, the IR camera does not allow to see the object under clothing, if an image, produced by this camera, is used directly. Of course, this is a big disadvantage for a security problem solution based on the IR camera using. To overcome this disadvantage we develop novel approach for computer processing of IR camera images. It allows us to increase a temperature resolution of IR camera as well as increasing of human year effective susceptibility. As a consequence of this, a possibility for seeing of a human body temperature changing through clothing appears. We analyze IR images of a person, which drinks water and eats chocolate. We follow a temperature trace on human body skin, caused by changing of temperature inside the human body. Some experiments were made with measurements of a body temperature covered by T-shirt. Shown results are very important for the detection of forbidden objects, cancelled inside the human body, by using non-destructive control without using X-rays.

High-resolution x-ray imaging using a structured scintillator

Energy Technology Data Exchange (ETDEWEB)

Hormozan, Yashar, E-mail: hormozan@kth.se; Sychugov, Ilya; Linnros, Jan [Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, Kista, Stockholm SE-16440 (Sweden)

2016-02-15

Purpose: In this study, the authors introduce a new generation of finely structured scintillators with a very high spatial resolution (a few micrometers) compared to conventional scintillators, yet maintaining a thick absorbing layer for improved detectivity. Methods: Their concept is based on a 2D array of high aspect ratio pores which are fabricated by ICP etching, with spacings (pitches) of a few micrometers, on silicon and oxidation of the pore walls. The pores were subsequently filled by melting of powdered CsI(Tl), as the scintillating agent. In order to couple the secondary emitted photons of the back of the scintillator array to a CCD device, having a larger pixel size than the pore pitch, an open optical microscope with adjustable magnification was designed and implemented. By imaging a sharp edge, the authors were able to calculate the modulation transfer function (MTF) of this finely structured scintillator. Results: The x-ray images of individually resolved pores suggest that they have been almost uniformly filled, and the MTF measurements show the feasibility of a few microns spatial resolution imaging, as set by the scintillator pore size. Compared to existing techniques utilizing CsI needles as a structured scintillator, their results imply an almost sevenfold improvement in resolution. Finally, high resolution images, taken by their detector, are presented. Conclusions: The presented work successfully shows the functionality of their detector concept for high resolution imaging and further fabrication developments are most likely to result in higher quantum efficiencies.

Special issue on high-resolution optical imaging

Science.gov (United States)

Smith, Peter J. S.; Davis, Ilan; Galbraith, Catherine G.; Stemmer, Andreas

2013-09-01

The pace of development in the field of advanced microscopy is truly breath-taking, and is leading to major breakthroughs in our understanding of molecular machines and cell function. This special issue of Journal of Optics draws attention to a number of interesting approaches, ranging from fluorescence and imaging of unlabelled cells, to computational methods, all of which are describing the ever increasing detail of the dynamic behaviour of molecules in the living cell. This is a field which traditionally, and currently, demonstrates a marvellous interplay between the disciplines of physics, chemistry and biology, where apparent boundaries to resolution dissolve and living cells are viewed in ever more clarity. It is fertile ground for those interested in optics and non-conventional imaging to contribute high-impact outputs in the fields of cell biology and biomedicine. The series of articles presented here has been selected to demonstrate this interdisciplinarity and to encourage all those with a background in the physical sciences to 'dip their toes' into the exciting and dynamic discoveries surrounding cell function. Although single molecule super-resolution microscopy is commercially available, specimen preparation and interpretation of single molecule data remain a major challenge for scientists wanting to adopt the techniques. The paper by Allen and Davidson [1] provides a much needed detailed introduction to the practical aspects of stochastic optical reconstruction microscopy, including sample preparation, image acquisition and image analysis, as well as a brief description of the different variants of single molecule localization microscopy. Since super-resolution microscopy is no longer restricted to three-dimensional imaging of fixed samples, the review by Fiolka [2] is a timely introduction to techniques that have been successfully applied to four-dimensional live cell super-resolution microscopy. The combination of multiple high-resolution techniques

Development of integrated platform based on chalcogenides for sensing applications in the mid-infrared

Science.gov (United States)

Gutierrez-Arroyo, Aldo; Bodiou, Loïc.; Lemaitre, Jonathan; Baudet, Emeline; Baillieul, Marion; Hardy, Isabelle; Caillaud, Celine; Colas, Florent; Boukerma, Kada; Rinnert, Emmanuel; Michel, Karine; Bureau, Bruno; Nazabal, Virginie; Charrier, Joël.

2018-03-01

Mid-Infrared (mid-IR) spectral range, spanning from 2 μm to 20 μm, is ideal for chemical sensing using spectroscopy thanks to the presence of vibrational absorption bands of many liquid and gas substances in this wavelength range. Indeed, mid-IR spectroscopy allows simultaneous qualitative and quantitative analysis by, respectively, identifying molecules from their spectral signature and relating the concentrations of different chemical agents to their absorption coefficient according to Beer-Lambert law. In the last years, photonic integrated sensors based on mid-IR spectroscopy have emerged as a cheap, accurate, and compact solution that would enable continuous real-time on-site diagnostics and monitoring of molecular species without the need to collect samples for off-site measurements. Here, we report the design, processing and characterization of a photonic integrated transducer based on selenide ridge waveguides. Evanescent wave detection of chemical substances in liquid phase (isopropyl alcohol, C3H8O, and acetic acid, C2H4O2, both dissolved in cyclohexane) is presented using their absorption at a wavelength of 7.7 μm.

A MID-INFRARED CENSUS OF STAR FORMATION ACTIVITY IN BOLOCAM GALACTIC PLANE SURVEY SOURCES

International Nuclear Information System (INIS)

Dunham, Miranda K.; Robitaille, Thomas P.; Evans, Neal J. II; Schlingman, Wayne M.; Cyganowski, Claudia J.; Urquhart, James

2011-01-01

We present the results of a search for mid-infrared signs of star formation activity in the 1.1 mm sources in the Bolocam Galactic Plane Survey (BGPS). We have correlated the BGPS catalog with available mid-IR Galactic plane catalogs based on the Spitzer Space Telescope GLIMPSE legacy survey and the Midcourse Space Experiment (MSX) Galactic plane survey. We find that 44% (3712 of 8358) of the BGPS sources contain at least one mid-IR source, including 2457 of 5067 (49%) within the area where all surveys overlap (10 deg. s tarlessBGPS sources which were not matched to any mid-IR sources. The mean 1.1 mm flux of each group increases with increasing probability of active star formation. We also find that the 'starless' BGPS sources are the most compact, while the sources with the highest probability of star formation activity are on average more extended with large skirts of emission. A subsample of 280 BGPS sources with known distances demonstrates that mass and mean H 2 column density also increase with probability of star formation activity.

Refinement procedure for the image alignment in high-resolution electron tomography.

Science.gov (United States)

Houben, L; Bar Sadan, M

2011-01-01

High-resolution electron tomography from a tilt series of transmission electron microscopy images requires an accurate image alignment procedure in order to maximise the resolution of the tomogram. This is the case in particular for ultra-high resolution where even very small misalignments between individual images can dramatically reduce the fidelity of the resultant reconstruction. A tomographic-reconstruction based and marker-free method is proposed, which uses an iterative optimisation of the tomogram resolution. The method utilises a search algorithm that maximises the contrast in tomogram sub-volumes. Unlike conventional cross-correlation analysis it provides the required correlation over a large tilt angle separation and guarantees a consistent alignment of images for the full range of object tilt angles. An assessment based on experimental reconstructions shows that the marker-free procedure is competitive to the reference of marker-based procedures at lower resolution and yields sub-pixel accuracy even for simulated high-resolution data. Copyright © 2011 Elsevier B.V. All rights reserved.

Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A{sup *}

Energy Technology Data Exchange (ETDEWEB)

Yusef-Zadeh, F.; Royster, M. J.; Roberts, D. A. [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Wardle, M. [Department of Physics and Astronomy and Research Center for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney NSW 2109 (Australia); Cotton, W.; Kunneriath, D. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Schödel, R. [Instituto de Astfisica de Andalucia (CSIC), Glorieta de la Astronomia S/N, E-18008 Granada (Spain)

2017-03-01

We present radio and millimeter continuum observations of the Galactic center taken with the Very Large Array (VLA) and ALMA at 44 and 226 GHz, respectively. We detect radio and millimeter emission from IRS 3, lying ∼4.″5 NW of Sgr A*, with a spectrum that is consistent with the photospheric emission from an AGB star at the Galactic center. Millimeter images reveal that the envelope of IRS 3, the brightest and most extended 3.8 μ m Galactic center stellar source, consists of two semicircular dust shells facing the direction of Sgr A*. The outer circumstellar shell, at a distance of 1.6 × 10{sup 4} au, appears to break up into “fingers” of dust directed toward Sgr A*. These features coincide with molecular CS (5–4) emission and a near-IR extinction cloud distributed between IRS 3 and Sgr A*. The NE–SW asymmetric shapes of the IRS 3 shells seen at 3.8 μ m and radio are interpreted as structures that are tidally distorted by Sgr A*. Using the kinematics of CS emission and the proper motion of IRS 3, the tidally distorted outflowing material from the envelope after 5000 yr constrains the distance of IRS 3 to ∼0.7 pc in front of or ∼0.5 pc behind Sgr A*. This suggests that the mass loss by stars near Sgr A* can supply a reservoir of molecular material near Sgr A*. We also present dark features in radio continuum images coincident with the envelope of IRS 3. These dusty stars provide examples in which high-resolution radio continuum images can identify dust-enshrouded stellar sources embedded in an ionized medium.

Exploration of the Infrared Sensitivity for a ZnSe Electrode of an IR Image Converter

Science.gov (United States)

Kurt, H. Hilal

2018-05-01

Significant improvement has been carried out in the field of the II-VI group semiconductor device technology. Semiconductors based on the II-VI group are attractive due to their alternative uses for thermal imaging systems and photonic applications. This study focuses on experimental work on the optical, electrical and structural characterization of an infrared (IR) photodetector zinc selenide (ZnSe). In addition, the IR sensitivity of the ZnSe has primarily been investigated by exploiting the IR responses of the material for various gas pressures, p, and interelectrode distances, d, in the IR converter. The experimental findings include the results of plasma current and plasma discharge emission under various illumination conditions in the IR region. The electron density distributions inside the gas discharge gap have also been simulated in two-dimensional media. Experimentally, the current-voltage, current-time, and discharge light emission plots are produced for a wide experimental parameter range. Consequently, the structural and optical properties have been studied through atomic force microscopy and Fourier-transform infrared spectroscopy techniques to obtain a comprehensive knowledge of the material.

Effects of whispering gallery mode in microsphere super-resolution imaging

Science.gov (United States)

Zhou, Song; Deng, Yongbo; Zhou, Wenchao; Yu, Muxin; Urbach, H. P.; Wu, Yihui

2017-09-01

Whispering Gallery modes have been presented in microscopic glass spheres or toruses with many applications. In this paper, the possible approaches to enhance the imaging resolution by Whispering Gallery modes are discussed, including evanescent waves coupling, transformed and illustration by Whispering Gallery modes. It shows that the high-order scattering modes play the dominant role in the reconstructed virtual image when the Whispering Gallery modes exist. Furthermore, we find that the high image resolution of electric dipoles can be achieved, when the out-of-phase components exist from the illustration of Whispering Gallery modes. Those results of our simulation could contribute to the knowledge of microsphere-assisted super-resolution imaging and its potential applications.

High resolution multiplexed functional imaging in live embryos (Conference Presentation)

Science.gov (United States)

Xu, Dongli; Zhou, Weibin; Peng, Leilei

2017-02-01

Fourier multiplexed fluorescence lifetime imaging (FmFLIM) scanning laser optical tomography (FmFLIM-SLOT) combines FmFLIM and Scanning laser optical tomography (SLOT) to perform multiplexed 3D FLIM imaging of live embryos. The system had demonstrate multiplexed functional imaging of zebrafish embryos genetically express Foster Resonant Energy Transfer (FRET) sensors. However, previous system has a 20 micron resolution because the focused Gaussian beam diverges quickly from the focused plane, makes it difficult to achieve high resolution imaging over a long projection depth. Here, we present a high-resolution FmFLIM-SLOT system with achromatic Bessel beam, which achieves 3 micron resolution in 3D deep tissue imaging. In Bessel-FmFLIM-SLOT, multiple laser excitation lines are firstly intensity modulated by a Michelson interferometer with a spinning polygon mirror optical delay line, which enables Fourier multiplexed multi-channel lifetime measurements. Then, a spatial light modulator and a prism are used to transform the modulated Gaussian laser beam to an achromatic Bessel beam. The achromatic Bessel beam scans across the whole specimen with equal angular intervals as sample rotated. After tomography reconstruction and the frequency domain lifetime analysis method, both the 3D intensity and lifetime image of multiple excitation-emission can be obtained. Using Bessel-FmFLIM-SLOT system, we performed cellular-resolution FLIM tomography imaging of live zebrafish embryo. Genetically expressed FRET sensors in these embryo will allow non-invasive observation of multiple biochemical processes in vivo.

Statistical iterative reconstruction to improve image quality for digital breast tomosynthesis

International Nuclear Information System (INIS)

Xu, Shiyu; Chen, Ying; Lu, Jianping; Zhou, Otto

2015-01-01

Purpose: Digital breast tomosynthesis (DBT) is a novel modality with the potential to improve early detection of breast cancer by providing three-dimensional (3D) imaging with a low radiation dose. 3D image reconstruction presents some challenges: cone-beam and flat-panel geometry, and highly incomplete sampling. A promising means to overcome these challenges is statistical iterative reconstruction (IR), since it provides the flexibility of accurate physics modeling and a general description of system geometry. The authors’ goal was to develop techniques for applying statistical IR to tomosynthesis imaging data. Methods: These techniques include the following: a physics model with a local voxel-pair based prior with flexible parameters to fine-tune image quality; a precomputed parameter λ in the prior, to remove data dependence and to achieve a uniform resolution property; an effective ray-driven technique to compute the forward and backprojection; and an oversampled, ray-driven method to perform high resolution reconstruction with a practical region-of-interest technique. To assess the performance of these techniques, the authors acquired phantom data on the stationary DBT prototype system. To solve the estimation problem, the authors proposed an optimization-transfer based algorithm framework that potentially allows fewer iterations to achieve an acceptably converged reconstruction. Results: IR improved the detectability of low-contrast and small microcalcifications, reduced cross-plane artifacts, improved spatial resolution, and lowered noise in reconstructed images. Conclusions: Although the computational load remains a significant challenge for practical development, the superior image quality provided by statistical IR, combined with advancing computational techniques, may bring benefits to screening, diagnostics, and intraoperative imaging in clinical applications

Statistical iterative reconstruction to improve image quality for digital breast tomosynthesis

Energy Technology Data Exchange (ETDEWEB)

Xu, Shiyu, E-mail: shiyu.xu@gmail.com; Chen, Ying, E-mail: adachen@siu.edu [Department of Electrical and Computer Engineering, Southern Illinois University Carbondale, Carbondale, Illinois 62901 (United States); Lu, Jianping; Zhou, Otto [Department of Physics and Astronomy and Curriculum in Applied Sciences and Engineering, University of North Carolina Chapel Hill, Chapel Hill, North Carolina 27599 (United States)

2015-09-15

Purpose: Digital breast tomosynthesis (DBT) is a novel modality with the potential to improve early detection of breast cancer by providing three-dimensional (3D) imaging with a low radiation dose. 3D image reconstruction presents some challenges: cone-beam and flat-panel geometry, and highly incomplete sampling. A promising means to overcome these challenges is statistical iterative reconstruction (IR), since it provides the flexibility of accurate physics modeling and a general description of system geometry. The authors’ goal was to develop techniques for applying statistical IR to tomosynthesis imaging data. Methods: These techniques include the following: a physics model with a local voxel-pair based prior with flexible parameters to fine-tune image quality; a precomputed parameter λ in the prior, to remove data dependence and to achieve a uniform resolution property; an effective ray-driven technique to compute the forward and backprojection; and an oversampled, ray-driven method to perform high resolution reconstruction with a practical region-of-interest technique. To assess the performance of these techniques, the authors acquired phantom data on the stationary DBT prototype system. To solve the estimation problem, the authors proposed an optimization-transfer based algorithm framework that potentially allows fewer iterations to achieve an acceptably converged reconstruction. Results: IR improved the detectability of low-contrast and small microcalcifications, reduced cross-plane artifacts, improved spatial resolution, and lowered noise in reconstructed images. Conclusions: Although the computational load remains a significant challenge for practical development, the superior image quality provided by statistical IR, combined with advancing computational techniques, may bring benefits to screening, diagnostics, and intraoperative imaging in clinical applications.

Subwavelength engineered fiber-to-chip silicon-on-sapphire interconnects for mid-infrared applications (Conference Presentation)

Science.gov (United States)

Alonso-Ramos, Carlos; Han, Zhaohong; Le Roux, Xavier; Lin, Hongtao; Singh, Vivek; Lin, Pao Tai; Tan, Dawn; Cassan, Eric; Marris-Morini, Delphine; Vivien, Laurent; Wada, Kazumi; Hu, Juejun; Agarwal, Anuradha; Kimerling, Lionel C.

2016-05-01

The mid-Infrared wavelength range (2-20 µm), so-called fingerprint region, contains the very sharp vibrational and rotational resonances of many chemical and biological substances. Thereby, on-chip absorption-spectrometry-based sensors operating in the mid-Infrared (mid-IR) have the potential to perform high-precision, label-free, real-time detection of multiple target molecules within a single sensor, which makes them an ideal technology for the implementation of lab-on-a-chip devices. Benefiting from the great development realized in the telecom field, silicon photonics is poised to deliver ultra-compact efficient and cost-effective devices fabricated at mass scale. In addition, Si is transparent up to 8 µm wavelength, making it an ideal material for the implementation of high-performance mid-IR photonic circuits. The silicon-on-insulator (SOI) technology, typically used in telecom applications, relies on silicon dioxide as bottom insulator. Unfortunately, silicon dioxide absorbs light beyond 3.6 µm, limiting the usability range of the SOI platform for the mid-IR. Silicon-on-sapphire (SOS) has been proposed as an alternative solution that extends the operability region up to 6 µm (sapphire absorption), while providing a high-index contrast. In this context, surface grating couplers have been proved as an efficient means of injecting and extracting light from mid-IR SOS circuits that obviate the need of cleaving sapphire. However, grating couplers typically have a reduced bandwidth, compared with facet coupling solutions such as inverse or sub-wavelength tapers. This feature limits their feasibility for absorption spectroscopy applications that may require monitoring wide wavelength ranges. Interestingly, sub-wavelength engineering can be used to substantially improve grating coupler bandwidth, as demonstrated in devices operating at telecom wavelengths. Here, we report on the development of fiber-to-chip interconnects to ZrF4 optical fibers and integrated SOS

Sparse PDF maps for non-linear multi-resolution image operations

KAUST Repository

Hadwiger, Markus

2012-11-01

We introduce a new type of multi-resolution image pyramid for high-resolution images called sparse pdf maps (sPDF-maps). Each pyramid level consists of a sparse encoding of continuous probability density functions (pdfs) of pixel neighborhoods in the original image. The encoded pdfs enable the accurate computation of non-linear image operations directly in any pyramid level with proper pre-filtering for anti-aliasing, without accessing higher or lower resolutions. The sparsity of sPDF-maps makes them feasible for gigapixel images, while enabling direct evaluation of a variety of non-linear operators from the same representation. We illustrate this versatility for antialiased color mapping, O(n) local Laplacian filters, smoothed local histogram filters (e.g., median or mode filters), and bilateral filters. © 2012 ACM.

THE MID-INFRARED EXTINCTION LAW AND ITS VARIATION IN THE COALSACK NEBULA

Energy Technology Data Exchange (ETDEWEB)

Wang Shu; Gao Jian; Jiang, B. W.; Chen Yang [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Li Aigen, E-mail: shuwang@mail.bnu.edu.cn, E-mail: jiangao@bnu.edu.cn, E-mail: bjiang@bnu.edu.cn, E-mail: cheny@bnu.edu.cn, E-mail: lia@missouri.edu [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States)

2013-08-10

In recent years, the wavelength dependence of interstellar extinction from the ultraviolet (UV) to the near- and mid-infrared (IR) has been studied extensively. Although it is well established that the UV/optical extinction law varies significantly among the different lines of sight, it is not clear how IR extinction varies among various environments. In this work, using the color-excess method and taking red giants as the extinction tracer, we determine interstellar extinction A{sub {lambda}} in the four Spitzer/IRAC bands in [3.6], [4.5], [5.8], [8.0] {mu}m (relative to A{sub K{sub s}}, extinction in the Two Micron All Sky Survey (2MASS) K{sub s} band at 2.16 {mu}m) of the Coalsack nebula, a nearby starless dark cloud, based on the data obtained from the 2MASS and Spitzer/GLIMPSE surveys. We select five individual regions across the nebula that span a wide variety of physical conditions ranging from diffuse and translucent to dense environments, as traced by the visual extinction, the Spitzer/MIPS 24 {mu}m emission, and CO emission. We find that A{sub {lambda}}/A{sub K{sub s}}, mid-IR extinction relative to A{sub K{sub s}}, decreases from diffuse to dense environments, which may be explained in terms of ineffective dust growth in dense regions. The mean extinction (relative to A{sub K{sub s}}) is calculated for the four IRAC bands as well and exhibits a flat mid-IR extinction law consistent with previous determinations for other regions. Extinction in the IRAC 4.5 {mu}m band is anomalously high, much higher than that of the other three IRAC bands, and cannot be explained in terms of CO and CO{sub 2} ice. Mid-IR extinction in the four IRAC bands has also been derived for four representative regions in the Coalsack Globule 2, which respectively exhibit strong ice absorption, moderate or weak ice absorption, and very weak or no ice absorption. The derived mid-IR extinction curves are all flat, with A{sub {lambda}}/A{sub K{sub s}} increasing with the decrease of the

THE MID-INFRARED EXTINCTION LAW AND ITS VARIATION IN THE COALSACK NEBULA

International Nuclear Information System (INIS)

Wang Shu; Gao Jian; Jiang, B. W.; Chen Yang; Li Aigen

2013-01-01

In recent years, the wavelength dependence of interstellar extinction from the ultraviolet (UV) to the near- and mid-infrared (IR) has been studied extensively. Although it is well established that the UV/optical extinction law varies significantly among the different lines of sight, it is not clear how IR extinction varies among various environments. In this work, using the color-excess method and taking red giants as the extinction tracer, we determine interstellar extinction A λ in the four Spitzer/IRAC bands in [3.6], [4.5], [5.8], [8.0] μm (relative to A K s , extinction in the Two Micron All Sky Survey (2MASS) K s band at 2.16 μm) of the Coalsack nebula, a nearby starless dark cloud, based on the data obtained from the 2MASS and Spitzer/GLIMPSE surveys. We select five individual regions across the nebula that span a wide variety of physical conditions ranging from diffuse and translucent to dense environments, as traced by the visual extinction, the Spitzer/MIPS 24 μm emission, and CO emission. We find that A λ /A K s , mid-IR extinction relative to A K s , decreases from diffuse to dense environments, which may be explained in terms of ineffective dust growth in dense regions. The mean extinction (relative to A K s ) is calculated for the four IRAC bands as well and exhibits a flat mid-IR extinction law consistent with previous determinations for other regions. Extinction in the IRAC 4.5 μm band is anomalously high, much higher than that of the other three IRAC bands, and cannot be explained in terms of CO and CO 2 ice. Mid-IR extinction in the four IRAC bands has also been derived for four representative regions in the Coalsack Globule 2, which respectively exhibit strong ice absorption, moderate or weak ice absorption, and very weak or no ice absorption. The derived mid-IR extinction curves are all flat, with A λ /A K s increasing with the decrease of the 3.1 μm H 2 O ice absorption optical depth τ ice

CCD and IR array controllers

Science.gov (United States)

Leach, Robert W.; Low, Frank J.

2000-08-01

A family of controllers has bene developed that is powerful and flexible enough to operate a wide range of CCD and IR focal plane arrays in a variety of ground-based applications. These include fast readout of small CCD and IR arrays for adaptive optics applications, slow readout of large CCD and IR mosaics, and single CCD and IR array operation at low background/low noise regimes as well as high background/high speed regimes. The CCD and IR controllers have a common digital core based on user- programmable digital signal processors that are used to generate the array clocking and signal processing signals customized for each application. A fiber optic link passes image data and commands to VME or PCI interface boards resident in a host computer to the controller. CCD signal processing is done with a dual slope integrator operating at speeds of up to one Megapixel per second per channel. Signal processing of IR arrays is done either with a dual channel video processor or a four channel video processor that has built-in image memory and a coadder to 32-bit precision for operating high background arrays. Recent developments underway include the implementation of a fast fiber optic data link operating at a speed of 12.5 Megapixels per second for fast image transfer from the controller to the host computer, and supporting image acquisition software and device drivers for the PCI interface board for the Sun Solaris, Linux and Windows 2000 operating systems.

Nuclear mid-infrared properties of nearby low-luminosity AGN

International Nuclear Information System (INIS)

Asmus, D; Duschl, W J; Hönig, S F; Gandhi, P; Smette, A

2012-01-01

We present ground-based high-spatial resolution mid-infrared (MIR) observations of 20 nearby low-luminosity AGN (LLAGN) with VLT/VISIR and the preliminary analysis of a new sample of 10 low-luminosity Seyferts observed with Gemini/Michelle. LLAGN are of great interest because these objects are the most common among active galaxies, especially in the nearby universe. Studying them in great detail makes it possible to investigate the AGN evolution over cosmic timescale. Indeed, many LLAGN likely represent the final stage of an AGN's lifetime. We show that even at low luminosities and accretion rates nuclear unresolved MIR emission is present in most objects. Compared to lower spatial resolution Spitzer/IRS spectra, the high-resolution MIR photometry exhibits significantly lower fluxes and different PAH emission feature properties in many cases. By using scaled Spitzer/IRS spectra of typical starburst galaxies, we show that the star formation contribution to the 12 μm emission is minor in the central parsecs of most LLAGN. Therefore, the observed MIR emission in the VISIR and Michelle data is most likely emitted by the AGN itself, which, for higher luminosity AGN, is interpreted as thermal emission from a dusty torus. Furthermore, the 12 /amemission of the LLAGN is strongly correlated with the absorption corrected 2-10 keV luminosity and the MIR- X-ray correlation found previously for AGN is extended to a range from 10 40 to 10 45 erg/s. This correlation is independent of the object type, and in particular the low-luminosity Seyferts observed with Michelle fall exactly on the power-law fit valid for brighter AGN. In addition, no dependency of the MIR-X-ray ratio on the accretion rate is found. These results are consistent with the unification model being applicable even in the probed low-luminosity regime.

Super-resolution convolutional neural network for the improvement of the image quality of magnified images in chest radiographs

Science.gov (United States)

Umehara, Kensuke; Ota, Junko; Ishimaru, Naoki; Ohno, Shunsuke; Okamoto, Kentaro; Suzuki, Takanori; Shirai, Naoki; Ishida, Takayuki

2017-02-01

Single image super-resolution (SR) method can generate a high-resolution (HR) image from a low-resolution (LR) image by enhancing image resolution. In medical imaging, HR images are expected to have a potential to provide a more accurate diagnosis with the practical application of HR displays. In recent years, the super-resolution convolutional neural network (SRCNN), which is one of the state-of-the-art deep learning based SR methods, has proposed in computer vision. In this study, we applied and evaluated the SRCNN scheme to improve the image quality of magnified images in chest radiographs. For evaluation, a total of 247 chest X-rays were sampled from the JSRT database. The 247 chest X-rays were divided into 93 training cases with non-nodules and 152 test cases with lung nodules. The SRCNN was trained using the training dataset. With the trained SRCNN, the HR image was reconstructed from the LR one. We compared the image quality of the SRCNN and conventional image interpolation methods, nearest neighbor, bilinear and bicubic interpolations. For quantitative evaluation, we measured two image quality metrics, peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). In the SRCNN scheme, PSNR and SSIM were significantly higher than those of three interpolation methods (pmethods without any obvious artifacts. These preliminary results indicate that the SRCNN scheme significantly outperforms conventional interpolation algorithms for enhancing image resolution and that the use of the SRCNN can yield substantial improvement of the image quality of magnified images in chest radiographs.

High-resolution investigations of edge effects in neutron imaging

International Nuclear Information System (INIS)

Strobl, M.; Kardjilov, N.; Hilger, A.; Kuehne, G.; Frei, G.; Manke, I.

2009-01-01

Edge enhancement is the main effect measured by the so-called inline or propagation-based neutron phase contrast imaging method. The effect has originally been explained by diffraction, and high spatial coherence has been claimed to be a necessary precondition. However, edge enhancement has also been found in conventional imaging with high resolution. In such cases the effects can produce artefacts and hinder quantification. In this letter the edge effects at cylindrical shaped samples and long straight edges have been studied in detail. The enhancement can be explained by refraction and total reflection. Using high-resolution imaging, where spatial resolutions better than 50 μm could be achieved, refraction and total reflection peaks - similar to diffraction patterns - could be separated and distinguished.

Three-dimensional super-resolution imaging for fluorescence emission difference microscopy

Energy Technology Data Exchange (ETDEWEB)

You, Shangting; Kuang, Cuifang, E-mail: cfkuang@zju.edu.cn; Li, Shuai; Liu, Xu; Ding, Zhihua [State key laboratory of modern optical instrumentations, Zhejiang University, Hangzhou 310027 (China)

2015-08-15

We propose a method theoretically to break the diffraction limit and to improve the resolution in all three dimensions for fluorescence emission difference microscopy. We produce two kinds of hollow focal spot by phase modulation. By incoherent superposition, these two kinds of focal spot yield a 3D hollow focal spot. The optimal proportion of these two kinds of spot is given in the paper. By employing 3D hollow focal spot, super-resolution image can be yielded by means of fluorescence emission difference microscopy, with resolution enhanced both laterally and axially. According to computation result, size of point spread function of three-dimensional super-resolution imaging is reduced by about 40% in all three spatial directions with respect to confocal imaging.

Effects of display resolution and size on primary diagnosis of chest images using a high-resolution electronic work station

International Nuclear Information System (INIS)

Fuhrman, C.R.; Cooperstein, L.A.; Herron, J.; Good, W.F.; Good, B.; Gur, D.; Maitz, G.; Tabor, E.; Hoy, R.J.

1987-01-01

To evaluate the acceptability of electronically displayed planar images, the authors have a high-resolution work station. This system utilizes a high-resolution film digitizer (100-micro resolution) interfaced to a mainframe computer and two high-resolution (2,048 X 2,048) display devices (Azuray). In a clinically simulated multiobserver blind study (19 cases and five observers) a prodetermined series of reading sessions is stored on magnetic disk and is transferred to the displays while the preceding set of images is being reviewed. Images can be linearly processed on the fly into 2,000 X 2,000 full resolution, 1,000 X 1,000 minified display, or 1,000 X 1,000 interpolated for full-size display. Results of the study indicate that radiologists accept but do not like significant minification (more than X2), and they rate 2,000 X 2,000 images as having better diagnostic quality than 1,000 X 1,000 images

Deep convective cloud characterizations from both broadband imager and hyperspectral infrared sounder measurements

Science.gov (United States)

Ai, Yufei; Li, Jun; Shi, Wenjing; Schmit, Timothy J.; Cao, Changyong; Li, Wanbiao

2017-02-01

Deep convective storms have contributed to airplane accidents, making them a threat to aviation safety. The most common method to identify deep convective clouds (DCCs) is using the brightness temperature difference (BTD) between the atmospheric infrared (IR) window band and the water vapor (WV) absorption band. The effectiveness of the BTD method for DCC detection is highly related to the spectral resolution and signal-to-noise ratio (SNR) of the WV band. In order to understand the sensitivity of BTD to spectral resolution and SNR for DCC detection, a BTD to noise ratio method using the difference between the WV and IR window radiances is developed to assess the uncertainty of DCC identification for different instruments. We examined the case of AirAsia Flight QZ8501. The brightness temperatures (Tbs) over DCCs from this case are simulated for BTD sensitivity studies by a fast forward radiative transfer model with an opaque cloud assumption for both broadband imager (e.g., Multifunction Transport Satellite imager, MTSAT-2 imager) and hyperspectral IR sounder (e.g., Atmospheric Infrared Sounder) instruments; we also examined the relationship between the simulated Tb and the cloud top height. Results show that despite the coarser spatial resolution, BTDs measured by a hyperspectral IR sounder are much more sensitive to high cloud tops than broadband BTDs. As demonstrated in this study, a hyperspectral IR sounder can identify DCCs with better accuracy.

HIGH-RESOLUTION IMAGING OF THE ATLBS REGIONS: THE RADIO SOURCE COUNTS

Energy Technology Data Exchange (ETDEWEB)

Thorat, K.; Subrahmanyan, R.; Saripalli, L.; Ekers, R. D., E-mail: kshitij@rri.res.in [Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)

2013-01-01

The Australia Telescope Low-brightness Survey (ATLBS) regions have been mosaic imaged at a radio frequency of 1.4 GHz with 6'' angular resolution and 72 {mu}Jy beam{sup -1} rms noise. The images (centered at R.A. 00{sup h}35{sup m}00{sup s}, decl. -67 Degree-Sign 00'00'' and R.A. 00{sup h}59{sup m}17{sup s}, decl. -67 Degree-Sign 00'00'', J2000 epoch) cover 8.42 deg{sup 2} sky area and have no artifacts or imaging errors above the image thermal noise. Multi-resolution radio and optical r-band images (made using the 4 m CTIO Blanco telescope) were used to recognize multi-component sources and prepare a source list; the detection threshold was 0.38 mJy in a low-resolution radio image made with beam FWHM of 50''. Radio source counts in the flux density range 0.4-8.7 mJy are estimated, with corrections applied for noise bias, effective area correction, and resolution bias. The resolution bias is mitigated using low-resolution radio images, while effects of source confusion are removed by using high-resolution images for identifying blended sources. Below 1 mJy the ATLBS counts are systematically lower than the previous estimates. Showing no evidence for an upturn down to 0.4 mJy, they do not require any changes in the radio source population down to the limit of the survey. The work suggests that automated image analysis for counts may be dependent on the ability of the imaging to reproduce connecting emission with low surface brightness and on the ability of the algorithm to recognize sources, which may require that source finding algorithms effectively work with multi-resolution and multi-wavelength data. The work underscores the importance of using source lists-as opposed to component lists-and correcting for the noise bias in order to precisely estimate counts close to the image noise and determine the upturn at sub-mJy flux density.

Lateral resolution of eddy current imaging

International Nuclear Information System (INIS)

Hassan, W.; Blodgett, M.; Nagy, P.B.

2002-01-01

Analytical, finite element simulation, and experimental methods were used to investigate the lateral resolution of eddy current microscopy. It was found that the lateral resolution of eddy current imaging is ultimately limited by the probe-coil geometry and dimensions, but both the inspection frequency and the phase angle can be used to optimize the resolution, to some degree, at the expense of sensitivity. Electric anisotropy exhibited by noncubic crystallographic classes of materials such as titanium alloys can play a very similar role in electromagnetic materials characterization of polycrystalline metals to that of elastic anisotropy in ultrasonic materials characterization. Our results demonstrate that eddy current microscopy can be enhanced via a high-resolution, small diameter probe-coil which delivers a unique materials characterization tool well suited for the evaluation of Ti alloys

Using Adobe Acrobat to create high-resolution line art images.

Science.gov (United States)

Woo, Hyoun Sik; Lee, Jeong Min

2009-08-01

The purpose of this article is to introduce a method for using Adobe Acrobat to make high-resolution and high-quality line art images. High-resolution and high-quality line art images for radiology journal submission can be generated using Adobe Acrobat as a steppingstone, and the customized PDF conversion settings can be used for converting hybrid images, including both bitmap and vector components.

Silicon Based Mid Infrared SiGeSn Heterostructure Emitters and Detectors

Science.gov (United States)

2016-05-16

AFRL-AFOSR-JP-TR-2016-0054 Silicon based mid infrared SiGeSn heterostrcture emitters and detectors Greg Sun UNIVERSITY OF MASSACHUSETTS Final Report... Silicon Based Mid Infrared SiGeSn Heterostructure Emitters and Detectors ” February 10, 2016 Principal Investigator: Greg Sun Engineering...diodes are incompatible with the CMOS process and therefore cannot be easily integrated with Si electronics . The GeSn mid IR detectors developed in

GALAXY CLUSTERS IN THE IRAC DARK FIELD. II. MID-INFRARED SOURCES

International Nuclear Information System (INIS)

Krick, J. E.; Surace, J. A.; Yan, L.; Thompson, D.; Ashby, M. L. N.; Hora, J. L.; Gorjian, V.

2009-01-01

We present infrared (IR) luminosities, star formation rates (SFR), colors, morphologies, locations, and active galactic nuclei (AGNs) properties of 24 μm detected sources in photometrically detected high-redshift clusters in order to understand the impact of environment on star formation (SF) and AGN evolution in cluster galaxies. We use three newly identified z = 1 clusters selected from the IRAC dark field; the deepest ever mid-IR survey with accompanying, 14 band multiwavelength data including deep Hubble Space Telescope imaging and deep wide-area Spitzer MIPS 24 μm imaging. We find 90 cluster members with MIPS detections within two virial radii of the cluster centers, of which 17 appear to have spectral energy distributions dominated by AGNs and the rest dominated by SF. We find that 43% of the star-forming sample have IR luminosities L IR > 10 11 L sun (luminous IR galaxies). The majority of sources (81%) are spirals or irregulars. A large fraction (at least 25%) show obvious signs of interactions. The MIPS-detected member galaxies have varied spatial distributions as compared to the MIPS-undetected members with one of the three clusters showing SF galaxies being preferentially located on the cluster outskirts, while the other two clusters show no such trend. Both the AGN fraction and the summed SFR of cluster galaxies increase from redshift zero to one, at a rate that is a few times faster in clusters than over the same redshift range in the field. Cluster environment does have an effect on the evolution of both AGN fraction and SFR from redshift one to the present, but does not affect the IR luminosities or morphologies of the MIPS sample. SF happens in the same way regardless of environment making MIPS sources look the same in the cluster and field, however the cluster environment does encourage a more rapid evolution with time as compared to the field.

Automated, feature-based image alignment for high-resolution imaging mass spectrometry of large biological samples

NARCIS (Netherlands)

Broersen, A.; Liere, van R.; Altelaar, A.F.M.; Heeren, R.M.A.; McDonnell, L.A.

2008-01-01

High-resolution imaging mass spectrometry of large biological samples is the goal of several research groups. In mosaic imaging, the most common method, the large sample is divided into a mosaic of small areas that are then analyzed with high resolution. Here we present an automated alignment

Real-time near-IR imaging of laser-ablation crater evolution in dental enamel

Science.gov (United States)

Darling, Cynthia L.; Fried, Daniel

2007-02-01

We have shown that the enamel of the tooth is almost completely transparent near 1310-nm in the near-infrared and that near-IR (NIR) imaging has considerable potential for the optical discrimination of sound and demineralized tissue and for observing defects in the interior of the tooth. Lasers are now routinely used for many applications in dentistry including the ablation of dental caries. The objective of this study was to test the hypothesis that real-time NIR imaging can be used to monitor laser-ablation under varying conditions to assess peripheral thermal and transient-stress induced damage and to measure the rate and efficiency of ablation. Moreover, NIR imaging may have considerable potential for monitoring the removal of demineralized areas of the tooth during cavity preparations. Sound human tooth sections of approximately 3-mm thickness were irradiated by a CO II laser under varying conditions with and without a water spray. The incision area in the interior of each sample was imaged using a tungsten-halogen lamp with band-pass filter centered at 131--nm combined with an InGaAs focal plane array with a NIR zoom microscope in transillumination. Due to the high transparency of enamel at 1310-nm, laser-incisions were clearly visible to the dentin-enamel junction and crack formation, dehydration and irreversible thermal changes were observed during ablation. This study showed that there is great potential for near-IR imaging to monitor laser-ablation events in real-time to: assess safe laser operating parameters by imaging thermal and stress-induced damage, elaborate the mechanisms involved in ablation such as dehydration, and monitor the removal of demineralized enamel.

Heuristic optimization in penumbral image for high resolution reconstructed image

International Nuclear Information System (INIS)

Azuma, R.; Nozaki, S.; Fujioka, S.; Chen, Y. W.; Namihira, Y.

2010-01-01

Penumbral imaging is a technique which uses the fact that spatial information can be recovered from the shadow or penumbra that an unknown source casts through a simple large circular aperture. The size of the penumbral image on the detector can be mathematically determined as its aperture size, object size, and magnification. Conventional reconstruction methods are very sensitive to noise. On the other hand, the heuristic reconstruction method is very tolerant of noise. However, the aperture size influences the accuracy and resolution of the reconstructed image. In this article, we propose the optimization of the aperture size for the neutron penumbral imaging.

Learning-based compressed sensing for infrared image super resolution

Science.gov (United States)

Zhao, Yao; Sui, Xiubao; Chen, Qian; Wu, Shaochi

2016-05-01

This paper presents an infrared image super-resolution method based on compressed sensing (CS). First, the reconstruction model under the CS framework is established and a Toeplitz matrix is selected as the sensing matrix. Compared with traditional learning-based methods, the proposed method uses a set of sub-dictionaries instead of two coupled dictionaries to recover high resolution (HR) images. And Toeplitz sensing matrix allows the proposed method time-efficient. Second, all training samples are divided into several feature spaces by using the proposed adaptive k-means classification method, which is more accurate than the standard k-means method. On the basis of this approach, a complex nonlinear mapping from the HR space to low resolution (LR) space can be converted into several compact linear mappings. Finally, the relationships between HR and LR image patches can be obtained by multi-sub-dictionaries and HR infrared images are reconstructed by the input LR images and multi-sub-dictionaries. The experimental results show that the proposed method is quantitatively and qualitatively more effective than other state-of-the-art methods.

Reconstructed Image Spatial Resolution of Multiple Coincidences Compton Imager

Science.gov (United States)

Andreyev, Andriy; Sitek, Arkadiusz; Celler, Anna

2010-02-01

We study the multiple coincidences Compton imager (MCCI) which is based on a simultaneous acquisition of several photons emitted in cascade from a single nuclear decay. Theoretically, this technique should provide a major improvement in localization of a single radioactive source as compared to a standard Compton camera. In this work, we investigated the performance and limitations of MCCI using Monte Carlo computer simulations. Spatial resolutions of the reconstructed point source have been studied as a function of the MCCI parameters, including geometrical dimensions and detector characteristics such as materials, energy and spatial resolutions.

Cascaded nano-porous silicon for high sensitive biosensing and functional group distinguishing by Mid-IR spectra.

Science.gov (United States)

Nguyen, Minh-Hang; Tsai, Hau-Jie; Wu, Jen-Kuei; Wu, Yi-Shiuan; Lee, Ming-Chang; Tseng, Fan-Gang

2013-09-15

We present a chemical-biosensor in the Mid-IR range and based on cascaded porous silicon made on p- and n-type (100) silicon substrates of resistivities between 0.001Ωcm and 0.005Ωcm. The stacked porous layers of various porosities (20-80%) and thicknesses (5-9μm) are formed by successive electrochemical etchings with different current densities. Working with FTIR technique that possesses fast response, high sensitivity, and capability of detecting and identifying functional groups, the cascaded porous structures provided enhanced refractive index sensitivities and reduced detection limits in chemical and biodetection. The largest wavenumber shifts were 50cm(-1)/mM obtained for d-(+)-glucose and 96cm(-1)/μg/mL for Cy5-conjungated Rabbit Anti-Mouse IgG. The lowest detectable concentration of glucose was 80μM (1.4mg/mL) with PS porosity of 40% and thickness of about 9μm while it was 40ng/mL for Cy5-conjugated Rabbit Anti-Mouse IgG which is 2.5×10(5) folds better than those in literature. Copyright © 2013 Elsevier B.V. All rights reserved.

Super-Resolution Enhancement From Multiple Overlapping Images: A Fractional Area Technique

Science.gov (United States)

Michaels, Joshua A.

With the availability of large quantities of relatively low-resolution data from several decades of space borne imaging, methods of creating an accurate, higher-resolution image from the multiple lower-resolution images (i.e. super-resolution), have been developed almost since such imagery has been around. The fractional-area super-resolution technique developed in this thesis has never before been documented. Satellite orbits, like Landsat, have a quantifiable variation, which means each image is not centered on the exact same spot more than once and the overlapping information from these multiple images may be used for super-resolution enhancement. By splitting a single initial pixel into many smaller, desired pixels, a relationship can be created between them using the ratio of the area within the initial pixel. The ideal goal for this technique is to obtain smaller pixels with exact values and no error, yielding a better potential result than those methods that yield interpolated pixel values with consequential loss of spatial resolution. A Fortran 95 program was developed to perform all calculations associated with the fractional-area super-resolution technique. The fractional areas are calculated using traditional trigonometry and coordinate geometry and Linear Algebra Package (LAPACK; Anderson et al., 1999) is used to solve for the higher-resolution pixel values. In order to demonstrate proof-of-concept, a synthetic dataset was created using the intrinsic Fortran random number generator and Adobe Illustrator CS4 (for geometry). To test the real-life application, digital pictures from a Sony DSC-S600 digital point-and-shoot camera with a tripod were taken of a large US geological map under fluorescent lighting. While the fractional-area super-resolution technique works in perfect synthetic conditions, it did not successfully produce a reasonable or consistent solution in the digital photograph enhancement test. The prohibitive amount of processing time (up to