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Sample records for 1024x1024 format pixel

  1. 1024x1024 Pixel MWIR and LWIR QWIP Focal Plane Arrays and 320x256 MWIR:LWIR Pixel Colocated Simultaneous Dualband QWIP Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, Sumith V.; Liu, John K.; Hill, Cory J.; Rafol, S. B.; Mumolo, Jason M.; Trinh, Joseph T.; Tidrow, M. Z.; Le Van, P. D.

    2005-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024x1024 pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NE(Delta)T) of 17 mK at a 95K operating temperature with f/2.5 optics at 300K background and the LWIR detector array has demonstrated a NE(Delta)T of 13 mK at a 70K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90K and 70K operating-temperatures respectively, with similar optical and background conditions. In addition, we are in the process of developing MWIR and LWIR pixel collocated simultaneously readable dualband QWIP focal plane arrays.

  2. 1024 x 1024 pixel mid-wavelength and long-wavelength infrared QWIP focal plane arrays for imaging applications

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Hill, C. J.; Rafol, S. B.; Mumolo, J. M.; Trinh, J. T.; Tidrow, M. Z.; LeVan, P. D.

    2005-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 10(24) x 10(24) pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NEAT) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NEAT of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In this paper, we will discuss the performance in terms of quantum efficiency, NE(delta)T, uniformity, operability and modulation transfer functions.

  3. 1024 x 1024 pixel mid-wavelength and long-wavelength infrared QWIP focal plane arrays for imaging applications

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Hill, C. J.; Rafol, S. B.; Mumolo, J. M.; Trinh, J. T.; Tidrow, M. Z.; LeVan, P. D.

    2005-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 10(24) x 10(24) pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NEAT) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NEAT of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In this paper, we will discuss the performance in terms of quantum efficiency, NE(delta)T, uniformity, operability and modulation transfer functions.

  4. A two-color 1024x1024 dynamic infrared scene projection system

    NASA Astrophysics Data System (ADS)

    LaVeigne, Joe; Franks, Greg; Prewarski, Marcus

    2013-05-01

    We report on the design and testing of a 2-color dynamic scene projector system based on the MIRAGE-XL infrared scene projector. The system is based on the optical combination of two 1024x1024 MIRAGE-XL resistive arrays. Algorithms derived for 2-color operation are discussed and system performance data is presented, including radiometric performance, sub-pixel spatial co-registration and compensation for spectral cross-talk.

  5. A New Large-Well 1024x1024 Si:As Detector for the Mid-Infrared

    NASA Technical Reports Server (NTRS)

    Mainzer, Amanda K.; Hong, John H.; Stapelbroek, M. G.; Hogue, Henry; Molyneux, Dale; Ressler, Michael E.; Watkins, Ernie; Reekstin, John; Werner, Mike; Young, Erick

    2005-01-01

    We present a description of a new 1024x1024 Si:As array designed for ground-based use from 5 - 28 microns. With a maximum well depth of 5e6 electrons, this device brings large-format array technology to bear on ground-based mid-infrared programs, allowing entry to the mega-pixel realm previously only accessible to the near-IR. The multiplexer design features switchable gain, a 256x256 windowing mode for extremely bright sources, and it is two-edge buttable. The device is currently in its final design phase at DRS in Cypress, CA. We anticipate completion of the foundry run in October 2005. This new array will enable wide field, high angular resolution ground-based follow up of targets found by space-based missions such as the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE).

  6. A New Large-Well 1024x1024 Si:As Detector for the Mid-Infrared

    NASA Technical Reports Server (NTRS)

    Mainzer, Amanda K.; Hong, John H.; Stapelbroek, M. G.; Hogue, Henry; Molyneux, Dale; Ressler, Michael E.; Watkins, Ernie; Reekstin, John; Werner, Mike; Young, Erick

    2005-01-01

    We present a description of a new 1024x1024 Si:As array designed for ground-based use from 5 - 28 microns. With a maximum well depth of 5e6 electrons, this device brings large-format array technology to bear on ground-based mid-infrared programs, allowing entry to the mega-pixel realm previously only accessible to the near-IR. The multiplexer design features switchable gain, a 256x256 windowing mode for extremely bright sources, and it is two-edge buttable. The device is currently in its final design phase at DRS in Cypress, CA. We anticipate completion of the foundry run in October 2005. This new array will enable wide field, high angular resolution ground-based follow up of targets found by space-based missions such as the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer (WISE).

  7. TEQUILA: NIR camera/spectrograph based on a Rockwell 1024x1024 HgCdTe FPA

    NASA Astrophysics Data System (ADS)

    Ruiz, Elfego; Sohn, Erika; Cruz-Gonzales, Irene; Salas, Luis; Parraga, Antonio; Perez, Manuel; Torres, Roberto; Cobos Duenas, Francisco J.; Gonzalez, Gaston; Langarica, Rosalia; Tejada, Carlos; Sanchez, Beatriz; Iriarte, Arturo; Valdez, J.; Gutierrez, Leonel; Lazo, Francisco; Angeles, Fernando

    1998-08-01

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

  8. ASTROCAM: offner re-imaging 1024 X 1024 InSb camera for near-infrared astrometry on the USNO 1.55-m telescope

    NASA Astrophysics Data System (ADS)

    Fischer, Jacqueline; Vrba, Frederick J.; Toomey, Douglas W.; Lucke, Bob L.; Wang, Shu-i.; Henden, Arne A.; Robichaud, Joseph L.; Onaka, Peter M.; Hicks, Brian; Harris, Frederick H.; Stahlberger, Werner E.; Kosakowski, Kris E.; Dudley, Charles C.; Johnston, Kenneth J.

    2003-03-01

    In order to extend the US Naval Observatory (USNO) small-angle astrometric capabilities to near infrared wavelengths we have designed and manufactured a 1024 x 1024 InSb re-imaging infrared camera equipped with an array selected from the InSb ALADDIN (Advanced Large Area Detector Development in InSb) development program and broadband and narrowband 0.8 - 3.8 μm filters. Since the USNO 1.55-m telescope is optimized for observations at visible wavelengths with an oversized secondary mirror and sky baffles, the straylight rejection capabilities of the ASTROCAM Lyot stop and baffles are of critical importance for its sensitivity and flat- fielding capabilities. An Offner relay was chosen for the heart of the system and was manufactured from the same melt of aluminum alloy to ensure homologous contraction from room temperature to 77 K. A blackened cone was installed behind the undersized hole (the Lyot stop) in the Offner secondary. With low distortion, a well-sampled point spread function, and a large field of view, the system is well suited for astrometry. It is telecentric, so any defocus will not result in a change of image scale. The DSP-based electronics allow readout of the entire array with double-correlated sampling in 0.19 seconds, but shorter readout is possible with single sampling or by reading out only small numbers of subarrays. In this paper we report on the optical, mechanical, and electronic design of the system and present images and results on the sensitivity and astrometric stability obtained with the system, now operating routinely at the 1.55-m telescope with a science-grade ALADDIN array.

  9. Large-format and multispectral QWIP infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Goldberg, Arnold C.; Choi, Kwong-Kit; Jhabvala, Murzy; La, Anh; Uppal, Parvez N.; Winn, Michael L.

    2003-09-01

    The next generation of infrared (IR) focal plane arrays (FPAs) will need to be a significant improvement in capability over those used in present-day second generation FLIRs. The Army's Future Combat System requires that the range for target identification be greater than the range of detection for an opposing sensor. To accomplish this mission, the number of pixels on the target must be considerably larger than that possible with 2nd generation FLIR. Therefore, the 3rd generation FLIR will need to be a large format staring FPA with more than 1000 pixels on each side. In addition, a multi-spectral capability will be required to allow operability in challenging ambient environments, discriminate targets from decoys, and to take advantage of the smaller diffraction blur in the MWIR for enhanced image resolution. We report on laboratory measurements of a large format (1024 x 1024 pixels) single-color LWIR IR FPA made using the corrugated quantum well infrared photodetector (QWIP) structure by the ARL/NASA team. The pixel pitch is 18 μm and the spectral response peaks at 8.8 μm with a 9.2 μm cutoff. We report on recent results using a MWIR/LWIR QWIP FPA to image the boost phase of a launch vehicle for missile defense applications and a LWIR/LWIR FPA designed specifically for detecting the disturbed soil associated with buried land mines. Finally, we report on the fabrication of a new read-out integrated circuit (ROIC) specifically designed for multi-spectral operation.

  10. New Sofradir VISIR-SWIR large format detector for next generation space missions

    NASA Astrophysics Data System (ADS)

    Fieque, Bruno; Jamin, Nicolas; Chorier, Philippe; Pidancier, Patricia; Baud, Laurent; Terrier, Bertrand

    2012-09-01

    For now more than 10 years, Sofradir is involved in SWIR detector manufacturing, developing and improving its SWIR detectors technology, leading to a mature technology that enables to address most of missions needs in term of performances, but also with respect to hard environmental constraints. SWIR detection range at Sofradir has been qualified for space applications thanks to various programs already run (APEX or Bepi-Colombo programs) or currently running (Sentinel 2, PRISMA mission). Recently, for PRISMA mission, Sofradir is extending its Visible-Near infra-red technology, called VISIR, to 1000x256 hyperspectral arrays. This technology has the huge advantage to enable detection in both visible range and SWIR detection range (0.4μm up to 2.5μm). As part of the development of large format infrared detectors, Sofradir has developed Jupiter 1280x1024, 15μm pixel pitch detector in mid 2000s and this detector is available at production level since the end of year 2000s. Based on the experiences acquired in SWIR and VISIR technologies as well as in the development of large format infrared detectors, since 2011, in the frame of an ESA program (named Next Generation Panchromatic detector), Sofradir is developing a new VISIR 1kx1k detector. This new detector has a format of 1024x1024 pixels with a 15 μm pixel pitch and it is adapted to spectral range from UV to SWIR domain. This development contains mainly two challenges: - the extension of the detector sensitivity down to UV spectral range - the development of a large format Readout Integrated Circuit (ROIC) with 15μm pixel pitch adapted to VISIR and SWIR spectral range involving in particular low input fluxes. In this paper, we will describe the architecture and functionalities of this new detector. The expected performances will be presented as well. Finally, main applications of this kind of detectors and expected spatial missions will be presented.

  11. Evaluation of large format electron bombarded virtual phase CCDs as ultraviolet imaging detectors

    NASA Technical Reports Server (NTRS)

    Opal, Chet B.; Carruthers, George R.

    1989-01-01

    In conjunction with an external UV-sensitive cathode, an electron-bombarded CCD may be used as a high quantum efficiency/wide dynamic range photon-counting UV detector. Results are presented for the case of a 1024 x 1024, 18-micron square pixel virtual phase CCD used with an electromagnetically focused f/2 Schmidt camera, which yields excellent simgle-photoevent discrimination and counting efficiency. Attention is given to the vacuum-chamber arrangement used to conduct system tests and the CCD electronics and data-acquisition systems employed.

  12. Evaluation of large format electron bombarded virtual phase CCDs as ultraviolet imaging detectors

    NASA Technical Reports Server (NTRS)

    Opal, Chet B.; Carruthers, George R.

    1989-01-01

    In conjunction with an external UV-sensitive cathode, an electron-bombarded CCD may be used as a high quantum efficiency/wide dynamic range photon-counting UV detector. Results are presented for the case of a 1024 x 1024, 18-micron square pixel virtual phase CCD used with an electromagnetically focused f/2 Schmidt camera, which yields excellent simgle-photoevent discrimination and counting efficiency. Attention is given to the vacuum-chamber arrangement used to conduct system tests and the CCD electronics and data-acquisition systems employed.

  13. Large Format Si:As IBC Array Performance for NGST and Future IR Space Telescope Applications

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Johnson, Roy; Love, Peter; Lum, Nancy; McKelvey, Mark; McCreight, Craig; McMurray, Robert, Jr.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    A mid-IR (5-30micrometer) instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. A space platform's greatly reduced thermal backgrounds (compared to airborne or ground-based platforms), allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. The previous generation's largest, in sensitive IR detectors at these wavelengths are 256x256 pixel Si:As Impurity Band Conduction (IBC) devices built by Raytheon Infrared Operations (RIO) for the Space Infrared Telescope Facility/Infrared Array Camera (SIRTF)/(IRAC) instrument. RIO has successfully enhanced these devices, increasing the pixel count by a factor of 16 while matching or exceeding SIRTF/IRAC device performance. NASA-ARC in collaboration with RIO has tested the first high performance large format (1024x 1024) Si:As IBC arrays for low background applications, such as for the middle instrument on Next Generation Space Telescope (NGST) and future IR Explorer missions. These hybrid devices consist of radiation hard SIRTF/IRAC-type Si:As IBC material mated to a readout multiplexer that has been specially processed for operation at low cryogenic temperatures (below 10K), yielding high device sensitivity over a wavelength range of 5-28 micrometers. We present laboratory testing results from these benchmark, devices. Continued development in this technology is essential for conducting large-area surveys of the local and early universe through observation and for complementing future missions such as NGST, Terrestrial Planet Finder (TPF), and Focal Plane Instruments and Requirement Science Team (FIRST).

  14. Large Format Si:As IBC Array Performance for NGST and Future IR Space Telescope Applications

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Johnson, Roy; Love, Peter; Lum, Nancy; McKelvey, Mark; McCreight, Craig; McMurray, Robert, Jr.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    A mid-IR (5-30micrometer) instrument aboard a cryogenic space telescope can have an enormous impact in resolving key questions in astronomy and cosmology. A space platform's greatly reduced thermal backgrounds (compared to airborne or ground-based platforms), allow for more sensitive observations of dusty young galaxies at high redshifts, star formation of solar-type stars in the local universe, and formation and evolution of planetary disks and systems. The previous generation's largest, in sensitive IR detectors at these wavelengths are 256x256 pixel Si:As Impurity Band Conduction (IBC) devices built by Raytheon Infrared Operations (RIO) for the Space Infrared Telescope Facility/Infrared Array Camera (SIRTF)/(IRAC) instrument. RIO has successfully enhanced these devices, increasing the pixel count by a factor of 16 while matching or exceeding SIRTF/IRAC device performance. NASA-ARC in collaboration with RIO has tested the first high performance large format (1024x 1024) Si:As IBC arrays for low background applications, such as for the middle instrument on Next Generation Space Telescope (NGST) and future IR Explorer missions. These hybrid devices consist of radiation hard SIRTF/IRAC-type Si:As IBC material mated to a readout multiplexer that has been specially processed for operation at low cryogenic temperatures (below 10K), yielding high device sensitivity over a wavelength range of 5-28 micrometers. We present laboratory testing results from these benchmark, devices. Continued development in this technology is essential for conducting large-area surveys of the local and early universe through observation and for complementing future missions such as NGST, Terrestrial Planet Finder (TPF), and Focal Plane Instruments and Requirement Science Team (FIRST).

  15. Pixel Perfect

    SciTech Connect

    Perrine, Kenneth A.; Hopkins, Derek F.; Lamarche, Brian L.; Sowa, Marianne B.

    2005-09-01

    Biologists and computer engineers at Pacific Northwest National Laboratory have specified, designed, and implemented a hardware/software system for performing real-time, multispectral image processing on a confocal microscope. This solution is intended to extend the capabilities of the microscope, enabling scientists to conduct advanced experiments on cell signaling and other kinds of protein interactions. FRET (fluorescence resonance energy transfer) techniques are used to locate and monitor protein activity. In FRET, it is critical that spectral images be precisely aligned with each other despite disturbances in the physical imaging path caused by imperfections in lenses and cameras, and expansion and contraction of materials due to temperature changes. The central importance of this work is therefore automatic image registration. This runs in a framework that guarantees real-time performance (processing pairs of 1024x1024, 8-bit images at 15 frames per second) and enables the addition of other types of advanced image processing algorithms such as image feature characterization. The supporting system architecture consists of a Visual Basic front-end containing a series of on-screen interfaces for controlling various aspects of the microscope and a script engine for automation. One of the controls is an ActiveX component written in C++ for handling the control and transfer of images. This component interfaces with a pair of LVDS image capture boards and a PCI board containing a 6-million gate Xilinx Virtex-II FPGA. Several types of image processing are performed on the FPGA in a pipelined fashion, including the image registration. The FPGA offloads work that would otherwise need to be performed by the main CPU and has a guaranteed real-time throughput. Image registration is performed in the FPGA by applying a cubic warp on one image to precisely align it with the other image. Before each experiment, an automated calibration procedure is run in order to set up the

  16. IRCAMDR: IRCAM3 Data Reduction Software

    NASA Astrophysics Data System (ADS)

    Aspin, Colin; McCaughrean, Mark; Bridger, Alan B.; Baines, Dave; Beard, Steven; Chan, S.; Giddings, Jack; Hartley, K. F.; Horsfield, A. P.; Kelly, B. D.; Emerson, J. P.; Currie, Malcolm J.; Economou, Frossie

    2014-06-01

    The UKIRT IRCAM3 data reduction and analysis software package, IRCAMDR (formerly ircam_clred) analyzes and displays any 2D data image stored in the standard Starlink (ascl:1110.012) NDF data format. It reduces and analyzes IRCAM1/2 data images of 62x58 pixels and IRCAM3 images of 256x256 size. Most of the applications will work on NDF images of any physical (pixel) dimensions, for example, 1024x1024 CCD images can be processed.

  17. Large format, small pixel pitch and hot detectors at SOFRADIR

    NASA Astrophysics Data System (ADS)

    Reibel, Y.; Rouvie, A.; Nedelcu, A.; Augey, T.; Pere-Laperne, N.; Rubaldo, L.; Billon-Lanfrey, D.; Gravrand, O.; Rothman, J.; Destefanis, G.

    2013-10-01

    Recently Sofradir joined a very small circle of IR detector manufacturers with expertise every aspect of the cooled and uncooled IR technologies, all under one roof by consolidating all IR technologies available in France. These different technologies are complementary and are used depending of the needs of the applications mainly concerning the detection range needs as well as their ability to detect in bad weather environmental conditions. SNAKE (InGaAs) and SCORPIO LW (MCT) expand Sofradir's line of small pixel pitch TV format IR detectors from the mid-wavelength to the short and long wavelengths. Our dual band MW-LW QWIP detectors (25μm, 384×288 pixels) benefit to tactical platforms giving an all-weather performance and increasing flexibility in the presence of battlefield obscurants. In parallel we have been pursuing further infrared developments on future MWIR detectors, such as the VGA format HOT detector that consumes 2W and the 10μm pitch IR detector which gives us a leading position in innovation. These detectors are designed for long-range surveillance equipment, commander or gunner sights, ground-to-ground missile launchers and other applications that require higher resolution and sensitivity to improve reconnaissance and target identification. This paper discusses the system level performance in each detector type.

  18. Mid-Wave and Long-Wave Infrared Dualband Megapixel QWIP Focal Plane Array

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Hill, C. J.; Ting, D. Z.; Kurth, E.; Woolaway, J.; LeVan, P. D.; Tidrow, M. Z.

    2008-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024x1024 pixel InGaAs/GaAs/AlGaAs based quantum well infrared photodetector (QWIP) focal planes and a 320x256 pixel dual-band pixel co-registered simultaneous QWIP focal plane array have been demonstrated as pathfinders. In this paper, we discuss the development of 1024x1024 MWIR/LWIR dual-band pixel co-registered simultaneous QWIP focal plane array.

  19. ASTROCAM: An Offner Re-imaging 1024 x 1024 InSb Camera for Near-Infrared Astrometry on the USNO 1.55-m Telescope

    DTIC Science & Technology

    2003-01-01

    Kosakowskif, C. C. Dudleya and Kenneth Johnstoni aNaval Research Laboratory, Remote Sensing Division, Washington, DC, USA bU.S. Naval Observatory ...Flagstaff Station, PO Box 1149, Flagstaff, AZ, USA cMauna Kea Infrared, LLC, 159 Kalanikoa St, Hilo, HI USA dUniversity of Chicago Engineering Center...gApplied Designs, 3001 Specific Heights Rd, Honolulu, HI, USA hCAD Services, 1158 Mowai St, Kailua, HI, USA iU.S. Naval Observatory , 3450 Massachusetts

  20. Multi-Color Megapixel QWIP focal plane arrays for remote sensing

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, S. V.; Liu, J. K.; Hill, C. J.; Rafol, S. B.; Mumolo, J. M.; Trinh, J. T.; Tidrow, M. Z.; LeVan, P. D.

    2005-01-01

    In this paper, we will discuss the performance in terms of quantum efficiency, NEAT, uniformity, operability, and modulation transfer functions of the 1024x1024 pixel arrays and the progress of dualband QWIP focal plane array development work.

  1. The formation of amplitude spectra in X-ray pixel detectors made of gallium arsenide.

    PubMed

    Ayzenshtat, Gennadiy; Prokopiev, Dmitriy; Baidali, Sergey; Tolbanov, Oleg; Dorzheeva, Larisa

    2017-02-21

    This study aims to analyse energy spectra formation in semiconductor X-ray pixel detectors using a simple experimental method. The calculations were performed for the pixel detectors made of high-resistivity gallium arsenide compensated by chromium GaAs (Cr). A peculiar feature of these detectors is an extremely short lifetime of the holes. When using ordinary detectors with planar electrodes the spectra with high energy resolution could not be observed. In this study, the shape of amplitude spectra of gamma rays were calculated with energy W0 = 60 and 17 keV. The calculations were performed for the pixel detector of GaAs (Cr) with the thickness of d = 500μm and pixel pitch of 50μm. The mobility of electrons and holes were assumed to be μn = 3000 cm2/Vs, μp = 300 cm2/Vs, and the lifetimes were τn = 20 ns and τp = 1 ns, respectively. It was demonstrated that in the pixel detector, where there was practically no collection of holes and the amplitude spectra occurred with the energy resolution of 3.5 keV. The calculations show that energy spectra of the pixel detectors has a high energy resolution at an appropriate polarity applied bias voltage. The calculation results were conformed by the experimental data.

  2. The wide-field imager for IXO: status and future activities

    NASA Astrophysics Data System (ADS)

    Strüder, Lothar; Aschauer, Florian; Bautz, Mark; Bombelli, Luca; Burrows, David; Fiorini, Carlo; Fraser, George; Herrmann, Sven; Kendziorra, Eckhard; Kuster, Markus; Lauf, Thomas; Lechner, Peter; Lutz, Gerhard; Majewski, Petra; Meuris, Aline; Porro, Matteo; Reiffers, Jonas; Richter, Rainer; Santangelo, Andrea; Soltau, Heike; Stefanescu, Alexander; Tenzer, Chris; Treis, Johannes; Tsunemi, Hiroshi; de Vita, Giulio; Wilms, Jörn

    2010-07-01

    The Wide Field Imager (WFI) of the International X-ray Observatory (IXO) is an X-ray imaging spectrometer based on a large monolithic DePFET (Depleted P-channel Field Effect Transistor) Active Pixel Sensor. Filling an area of 10 x 10 cm2 with a format of 1024 x 1024 pixels it will cover a field of view of 18 arcmin. The pixel size of 100 x 100 μm2 corresponds to a fivefold oversampling of the telescope's expected 5 arcsec point spread function. The WFI's basic DePFET structure combines the functionalities of sensor and integrated amplifier with nearly Fano-limited energy resolution and high efficiency from 100 eV to 15 keV. The development of dedicated control and amplifier ASICs allows for high frame rates up to 1 kHz and flexible readout modes. Results obtained with representative prototypes with a format of 256 x 256 pixels are presented.

  3. PIXEL PUSHER

    NASA Technical Reports Server (NTRS)

    Stanfill, D. F.

    1994-01-01

    Pixel Pusher is a Macintosh application used for viewing and performing minor enhancements on imagery. It will read image files in JPL's two primary image formats- VICAR and PDS - as well as the Macintosh PICT format. VICAR (NPO-18076) handles an array of image processing capabilities which may be used for a variety of applications including biomedical image processing, cartography, earth resources, and geological exploration. Pixel Pusher can also import VICAR format color lookup tables for viewing images in pseudocolor (256 colors). This program currently supports only eight bit images but will work on monitors with any number of colors. Arbitrarily large image files may be viewed in a normal Macintosh window. Color and contrast enhancement can be performed with a graphical "stretch" editor (as in contrast stretch). In addition, VICAR images may be saved as Macintosh PICT files for exporting into other Macintosh programs, and individual pixels can be queried to determine their locations and actual data values. Pixel Pusher is written in Symantec's Think C and was developed for use on a Macintosh SE30, LC, or II series computer running System Software 6.0.3 or later and 32 bit QuickDraw. Pixel Pusher will only run on a Macintosh which supports color (whether a color monitor is being used or not). The standard distribution medium for this program is a set of three 3.5 inch Macintosh format diskettes. The program price includes documentation. Pixel Pusher was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Think C is a trademark of Symantec Corporation. Macintosh is a registered trademark of Apple Computer, Inc.

  4. PIXEL PUSHER

    NASA Technical Reports Server (NTRS)

    Stanfill, D. F.

    1994-01-01

    Pixel Pusher is a Macintosh application used for viewing and performing minor enhancements on imagery. It will read image files in JPL's two primary image formats- VICAR and PDS - as well as the Macintosh PICT format. VICAR (NPO-18076) handles an array of image processing capabilities which may be used for a variety of applications including biomedical image processing, cartography, earth resources, and geological exploration. Pixel Pusher can also import VICAR format color lookup tables for viewing images in pseudocolor (256 colors). This program currently supports only eight bit images but will work on monitors with any number of colors. Arbitrarily large image files may be viewed in a normal Macintosh window. Color and contrast enhancement can be performed with a graphical "stretch" editor (as in contrast stretch). In addition, VICAR images may be saved as Macintosh PICT files for exporting into other Macintosh programs, and individual pixels can be queried to determine their locations and actual data values. Pixel Pusher is written in Symantec's Think C and was developed for use on a Macintosh SE30, LC, or II series computer running System Software 6.0.3 or later and 32 bit QuickDraw. Pixel Pusher will only run on a Macintosh which supports color (whether a color monitor is being used or not). The standard distribution medium for this program is a set of three 3.5 inch Macintosh format diskettes. The program price includes documentation. Pixel Pusher was developed in 1991 and is a copyrighted work with all copyright vested in NASA. Think C is a trademark of Symantec Corporation. Macintosh is a registered trademark of Apple Computer, Inc.

  5. Development of an ultra-high temperature infrared scene projector at Santa Barbara Infrared Inc.

    NASA Astrophysics Data System (ADS)

    Franks, Greg; Laveigne, Joe; Danielson, Tom; McHugh, Steve; Lannon, John; Goodwin, Scott

    2015-05-01

    The rapid development of very-large format infrared detector arrays has challenged the IR scene projector community to develop correspondingly larger-format infrared emitter arrays to support the testing needs of systems incorporating these detectors. As with most integrated circuits, fabrication yields for the read-in integrated circuit (RIIC) that drives the emitter pixel array are expected to drop dramatically with increasing size, making monolithic RIICs larger than the current 1024x1024 format impractical and unaffordable. Additionally, many scene projector users require much higher simulated temperatures than current technology can generate to fully evaluate the performance of their systems and associated processing algorithms. Under the Ultra High Temperature (UHT) development program, Santa Barbara Infrared Inc. (SBIR) is developing a new infrared scene projector architecture capable of producing both very large format (>1024x1024) resistive emitter arrays and improved emitter pixel technology capable of simulating very high apparent temperatures. During an earlier phase of the program, SBIR demonstrated materials with MWIR apparent temperatures in excess of 1000K. New emitter materials have subsequently been selected to produce pixels that achieve even higher apparent temperatures. Test results from pixels fabricated using the new material set will be presented and discussed. Also in development under the same UHT program is a 'scalable' RIIC that will be used to drive the high temperature pixels. This RIIC will utilize through-silicon vias (TSVs) and quilt packaging (QP) technologies to allow seamless tiling of multiple chips to fabricate very large arrays, and thus overcome the inherent yield limitations of very-large-scale integrated circuits. Current status of the RIIC development effort will also be presented.

  6. Comparative analysis of pixel resolution of standard digital imaging formats to Generation III image intensifiers based on nighttime man-size target recognition

    NASA Astrophysics Data System (ADS)

    Estrera, Joseph P.

    2009-05-01

    This paper presents a comparative analysis of pixel resolution of standard digital imaging formats to the imaging output of a Generation III image intensifier. The comparative analysis will focus on the application of recognition of a man size target at a specified distance in nighttime (starlight conditions) utilizing a 1X night vision system with 40° field of view (FOV). Simple geometric theory will be applied to determine image intensified pixel format, digital imaging formats, and man size target pixel coverage for respective imaging pixel format. Daylight and night time experiments are described in detail using the several digital CCD formats (640×480, 1280×1024, and 2615×1471) through a standard Generation III image intensifier (64 lp/mm) in a night vision monocular system (AN/PVS-14). Detailed image analysis is conducted and presented on experimental data. Paper has been cleared by DOD/OSR for Public Release under Ref: 05-S-0347 on December 13, 2004.

  7. VizieR Online Data Catalog: V1044 Her VR differential photometry (Lu+, 2016)

    NASA Astrophysics Data System (ADS)

    Lu, H.; Zhang, L.; Han, X. L.; Pi, Q.; Wang, D.

    2016-11-01

    V1044 Her was observed in the VR bands on May 22, 23 and 24, 2015 using the 60-cm reflecting telescope at Xinglong Station of the National Astronomical Observatories of China (NAOC). This telescope was equipped with a 1024x1024 pixel CCD and the standard Johnson UBVRI filters. (1 data file).

  8. Imaging MAMA detector systems. [Multi-Anode Microchannel Array

    NASA Technical Reports Server (NTRS)

    Slater, David C.; Timothy, J. G.; Morgan, Jeffrey S.; Kasle, David B.

    1990-01-01

    Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.

  9. Imaging MAMA detector systems. [Multi-Anode Microchannel Array

    NASA Technical Reports Server (NTRS)

    Slater, David C.; Timothy, J. G.; Morgan, Jeffrey S.; Kasle, David B.

    1990-01-01

    Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.

  10. Current Status of High Performance Large Format Si:As IBC Detectors for SOFIA-like Applications

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Greene, Thomas; McCreight, Craig; McKelvey, Mark; McMurray, Robert, Jr.; Cripe, Jerry; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Airborne and space telescope astronomical observations in the 5-25 micrometer wavelength region, are critical for understanding the physical conditions, composition, chemistry, and excitation of many environments in the interstellar medium, external galaxies, solar system objects, extra-solar systems, and stars. The scientific impact is particularly unique in the 5-8 micrometer and 14-25 micrometer regions which are inaccessible or poorly observed from ground-based observatories. Large-format area mid-infrared (MIR) detectors sensitive over these wavelengths and operable under moderate backgrounds (greater than 10(circumflex)6 e-/s at R=2000, 10(micrometers)) are essential for efficient large-area survey imaging and for taking moderate resolution spectra over a large spectral range. Both SOFIA and passively cooled Explorer observatories could benefit from this technology. Current first-light SOFIA instruments use small-format MIR FPA's of sizes 128x128 and 256x256, With the collaboration of Raytheon Infrared Operations (RIO), NASA-ARC has been testing the first device of this kind, a combination of 1) the ALADDIN III readout multiplexer, cryo-processed for 6K operation, with 2) SIRTF IRAC-like Sides IBC detector material. designed for higher QE and low dark current. Here we report requirements. design, and initial fabrication and testing of the first 1024x1024 Si:As IBC mid-IR detector array for these conditions. This device has exhibited low dark current, moderate noise levels, and greater than 200,000 electron linear well size at 6K operation. We conclude with suggestions for future device development for optimal performance under moderate background, SOFIA- and low Earth orbit observing conditions.

  11. Current Status of High Performance Large Format Si:As IBC Detectors for SOFIA-like Applications

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Greene, Thomas; McCreight, Craig; McKelvey, Mark; McMurray, Robert, Jr.; Cripe, Jerry; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    Airborne and space telescope astronomical observations in the 5-25 micrometer wavelength region, are critical for understanding the physical conditions, composition, chemistry, and excitation of many environments in the interstellar medium, external galaxies, solar system objects, extra-solar systems, and stars. The scientific impact is particularly unique in the 5-8 micrometer and 14-25 micrometer regions which are inaccessible or poorly observed from ground-based observatories. Large-format area mid-infrared (MIR) detectors sensitive over these wavelengths and operable under moderate backgrounds (greater than 10(circumflex)6 e-/s at R=2000, 10(micrometers)) are essential for efficient large-area survey imaging and for taking moderate resolution spectra over a large spectral range. Both SOFIA and passively cooled Explorer observatories could benefit from this technology. Current first-light SOFIA instruments use small-format MIR FPA's of sizes 128x128 and 256x256, With the collaboration of Raytheon Infrared Operations (RIO), NASA-ARC has been testing the first device of this kind, a combination of 1) the ALADDIN III readout multiplexer, cryo-processed for 6K operation, with 2) SIRTF IRAC-like Sides IBC detector material. designed for higher QE and low dark current. Here we report requirements. design, and initial fabrication and testing of the first 1024x1024 Si:As IBC mid-IR detector array for these conditions. This device has exhibited low dark current, moderate noise levels, and greater than 200,000 electron linear well size at 6K operation. We conclude with suggestions for future device development for optimal performance under moderate background, SOFIA- and low Earth orbit observing conditions.

  12. PixelLearn

    NASA Technical Reports Server (NTRS)

    Mazzoni, Dominic; Wagstaff, Kiri; Bornstein, Benjamin; Tang, Nghia; Roden, Joseph

    2006-01-01

    PixelLearn is an integrated user-interface computer program for classifying pixels in scientific images. Heretofore, training a machine-learning algorithm to classify pixels in images has been tedious and difficult. PixelLearn provides a graphical user interface that makes it faster and more intuitive, leading to more interactive exploration of image data sets. PixelLearn also provides image-enhancement controls to make it easier to see subtle details in images. PixelLearn opens images or sets of images in a variety of common scientific file formats and enables the user to interact with several supervised or unsupervised machine-learning pixel-classifying algorithms while the user continues to browse through the images. The machinelearning algorithms in PixelLearn use advanced clustering and classification methods that enable accuracy much higher than is achievable by most other software previously available for this purpose. PixelLearn is written in portable C++ and runs natively on computers running Linux, Windows, or Mac OS X.

  13. VizieR Online Data Catalog: Δa observations of 3 globular clusters (Paunzen+, 2014)

    NASA Astrophysics Data System (ADS)

    Paunzen, E.; Iliev, I. Kh.; Pintado, O. I.; Baum, H.; Maitzen, H. M.; Netopil, M.; Onehag, A.; Zejda, M.; Fraga, L.

    2015-04-01

    The observations of the three globular clusters were performed at two different sites: * 2m Ritchey-Chretien-Coude telescope [Bulgarian National Astronomical Observatory (BNAO, Rozhen)], direct imaging, SITe SI003AB 1024x1024-pixel CCD, 5' field of view, 1pixel=0.32arcsec, and * 2.15m telescope [El Complejo Astronomico El Leoncito (CASLEO)], direct imaging with focal reducer, TEK-1024 CCD, 9.5-arcmin field of view, 1pixel=0.813arcsec. (3 data files).

  14. Argus: a new 16-pixel millimeter-wave spectroscopic instrument for star formation studies at the Green Bank Telescope

    NASA Astrophysics Data System (ADS)

    Cunningham, Nichol; Frayer, David T.; Church, Sarah E.; Sieth, Matthew; Harris, Andrew I.; Cleary, Kieran; Gundersen, Joshua O.; Goldsmith, Paul; Chung, Dongwoo; Readhead, Anthony C. S.; gaier, todd; Kangaslahti, Pekka; Samoska, Lorene

    2017-01-01

    Argus is a new 16-pixel W-band focal plane array for millimeter spectroscopy at the Green Bank Telescope (GBT). Built by a consortium led by Sarah Church at Stanford, this new instrument provides fast astronomical imaging over the 75-116 GHz band and at high spatial resolution. The frequency range covered by Argus is of particular interest for star formation studies and will be excellent at probing cold, dense cores within star-forming regions, along with constraining the dynamics of filamentary structures withing giant molecular cloud complexes. In particular, the 3mm band covers a large number of important spectral lines, including CO (J=1-0) and its isotopologues, as well as HCO+, H13CO+, SiO, N2H+, HCN and HNC. These molecular transitions trace a combination of dense cold gas, shocked emission from jets and outflows as well as the signatures of infall, all of which are imperative constituents in the early stages of star formation. Argus on the GBT will provide the high sensitivity of a filled aperture along with a high angular resolution of 6-10", this resolution is well-matched to the mid- and far-infrared observations from the Spitzer, SOFIA, and Herschel telescopes. We report on the current status of Argus and present recent commissioning and early science highlights from Argus of 12CO, 13CO and HCO+ emission towards the massive star forming region, DR 21. Argus, currently under commissioning, is expected to be in full science mode in the winter semester of 2016.

  15. 4K×4K format 10μm pixel pitch H4RG-10 hybrid CMOS silicon visible focal plane array for space astronomy

    NASA Astrophysics Data System (ADS)

    Bai, Yibin; Tennant, William; Anglin, Selmer; Wong, Andre; Farris, Mark; Xu, Min; Holland, Eric; Cooper, Donald; Hosack, Joseph; Ho, Kenneth; Sprafke, Thomas; Kopp, Robert; Starr, Brian; Blank, Richard; Beletic, James W.; Luppino, Gerard A.

    2012-07-01

    Teledyne’s silicon hybrid CMOS focal plane array technology has matured into a viable, high performance and high- TRL alternative to scientific CCD sensors for space-based applications in the UV-visible-NIR wavelengths. This paper presents the latest results from Teledyne’s low noise silicon hybrid CMOS visible focal place array produced in 4K×4K format with 10 μm pixel pitch. The H4RG-10 readout circuit retains all of the CMOS functionality (windowing, guide mode, reference pixels) and heritage of its highly successful predecessor (H2RG) developed for JWST, with additional features for improved performance. Combined with a silicon PIN detector layer, this technology is termed HyViSI™ (Hybrid Visible Silicon Imager). H4RG-10 HyViSI™ arrays achieve high pixel interconnectivity (<99.99%), low readout noise (<10 e- rms single CDS), low dark current (<0.5 e-/pixel/s at 193K), high quantum efficiency (<90% broadband), and large dynamic range (<13 bits). Pixel crosstalk and interpixel capacitance (IPC) have been predicted using detailed models of the hybrid structure and these predictions have been confirmed by measurements with Fe-55 Xray events and the single pixel reset technique. For a 100-micron thick detector, IPC of less than 3% and total pixel crosstalk of less than 7% have been achieved for the HyViSI™ H4RG-10. The H4RG-10 array is mounted on a lightweight silicon carbide (SiC) package and has been qualified to Technology Readiness Level 6 (TRL-6). As part of space qualification, the HyViSI™ H4RG-10 array passed radiation testing for low earth orbit (LEO) environment.

  16. Modulation transfer function measurements of QWIP and superlattice focal plane arrays

    NASA Astrophysics Data System (ADS)

    Gunapala, S. D.; Ting, D. Z.; Rafol, S. B.; Soibel, A.; Khoshakhlagh, A.; Hill, C.; Liu, J. K.; Mumolo, J. M.; Keo, S. A.

    2013-01-01

    Modulation transfer function (MTF) is the ability of an imaging system to faithfully image a given object. The MTF of an imaging system quantifies the ability of the system to resolve or transfer spatial frequencies. In this presentation we will discuss the detail MTF measurements of 1024x1024 pixels multi-band quantum well infrared photodetector and 320x256 pixels long-wavelength InAs/GaSb superlattice infrared focal plane arrays.

  17. Performance characteristics of the imaging MAMA detector systems for SOHO, STIS, and FUSE/Lyman

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1991-01-01

    Imaging Extreme Ultraviolet (EUV) Multi-Anode Microchannel Array (MAMA) detector systems with formats of 360 x 1024 pixels and pixel dimensions of 25 x 25 sq microns are being fabricated and tested for flight in two instruments on the ESA/NASA Solar and Heliospheric Observatory (SOHO). In addition, very-large-format (1024 x 1024)- and (2048 x 2048)-pixel Far Ultraviolet (FUV) and EUV MAMA detectors with pixel dimensions of 25 x 25 sq microns are being fabricated and tested for use in the NASA Goddard Space Flight Center's Hubble Space Telescope Imaging Spectrograph (STIS), a second-generation instrument scheduled for in-orbit installation in 1997. Finally, FUV MAMA detectors with formats of 224 x 960 pixels and pixel dimensions of 14 x 14 sq microns are being evaluated as prototypes of the detector for the prime FUV spectrograph of the Far Ultraviolet Spectroscopic Explorer (FUSE/Lyman) mission. The configurations and performance characteristics of the different detector systems are described, and the plans for further development of the Advanced Technology MAMA detector system discussed.

  18. Digital Position Encoding Of Galvanometer Scanner In A Laser Microscope

    NASA Astrophysics Data System (ADS)

    Liljeborg, Anders

    1988-09-01

    An account is given of a realization of a feedback method to digitize the analog position signal from a moving iron galvanometer. It is employed in a confocal scanning laser microscope for generating digital images. The photometric sampling has to be closely coupled to the position of a mirror that scans a focused laser beam across a microscope specimen. Pictures with low geometric distortion are obtained up to the size 1024 x 1024 pixels.

  19. Pixel Color Magnitude Diagrams for Semi-resolved Stellar Populations: The Star Formation History of Regions within the Disk and Bulge of M31

    NASA Astrophysics Data System (ADS)

    Conroy, Charlie; van Dokkum, Pieter G.

    2016-08-01

    The analysis of stellar populations has, by and large, been developed for two limiting cases: spatially resolved stellar populations in the color-magnitude diagram, and integrated light observations of distant systems. In between these two extremes lies the semi-resolved regime, which encompasses a rich and relatively unexplored realm of observational phenomena. Here we develop the concept of pixel color-magnitude diagrams (pCMDs) as a powerful technique for analyzing stellar populations in the semi-resolved regime. pCMDs show the distribution of imaging data in the plane of pixel luminosity versus pixel color. A key feature of pCMDs is that they are sensitive to all stars, including both the evolved giants and the unevolved main sequence stars. An important variable in this regime is the mean number of stars per pixel, {N}{{pix}}. Simulated pCMDs demonstrate a strong sensitivity to the star formation history (SFH) and have the potential to break degeneracies between age, metallicity and dust based on two filter data for values of {N}{{pix}} up to at least 104. We extract pCMDs from Hubble Space Telescope optical imaging of M31 and derive SFHs with seven independent age bins from 106 to 1010 year for both the crowded disk and bulge regions (where {N}{{pix}}≈ 30{--}{10}3). From analyzing a small region of the disk we find a SFH that is smooth and consistent with an exponential decay timescale of 4 Gyr. The bulge SFH is also smooth and consistent with a 2 Gyr decay timescale. pCMDs will likely play an important role in maximizing the science returns from next generation ground and space-based facilities.

  20. Achieving ultra-high temperatures with a resistive emitter array

    NASA Astrophysics Data System (ADS)

    Danielson, Tom; Franks, Greg; Holmes, Nicholas; LaVeigne, Joe; Matis, Greg; McHugh, Steve; Norton, Dennis; Vengel, Tony; Lannon, John; Goodwin, Scott

    2016-05-01

    The rapid development of very-large format infrared detector arrays has challenged the IR scene projector community to also develop larger-format infrared emitter arrays to support the testing of systems incorporating these detectors. In addition to larger formats, many scene projector users require much higher simulated temperatures than can be generated with current technology in order to fully evaluate the performance of their systems and associated processing algorithms. Under the Ultra High Temperature (UHT) development program, Santa Barbara Infrared Inc. (SBIR) is developing a new infrared scene projector architecture capable of producing both very large format (>1024 x 1024) resistive emitter arrays and improved emitter pixel technology capable of simulating very high apparent temperatures. During earlier phases of the program, SBIR demonstrated materials with MWIR apparent temperatures in excess of 1400 K. New emitter materials have subsequently been selected to produce pixels that achieve even higher apparent temperatures. Test results from pixels fabricated using the new material set will be presented and discussed. A 'scalable' Read In Integrated Circuit (RIIC) is also being developed under the same UHT program to drive the high temperature pixels. This RIIC will utilize through-silicon via (TSV) and Quilt Packaging (QP) technologies to allow seamless tiling of multiple chips to fabricate very large arrays, and thus overcome the yield limitations inherent in large-scale integrated circuits. Results of design verification testing of the completed RIIC will be presented and discussed.

  1. Modulation Transfer Function of Infrared Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Rafol, S. B.; Ting, D. Z.; Soibel, A.; Hill, C. J.; Khoshakhlagh, A.; Liu, J. K.; Mumolo, J. M.; Hoglund, L.; Luong, E. M.

    2015-01-01

    Modulation transfer function (MTF) is the ability of an imaging system to faithfully image a given object. The MTF of an imaging system quantifies the ability of the system to resolve or transfer spatial frequencies. In this presentation we will discuss the detail MTF measurements of 1024x1024 pixels mid -wavelength and long- wavelength quantum well infrared photodetector, and 320x256 pixels long- wavelength InAs/GaSb superlattice infrared focal plane arrays (FPAs). Long wavelength Complementary Barrier Infrared Detector (CBIRD) based on InAs/GaSb superlattice material is hybridized to recently designed and fabricated 320x256 pixel format ROIC. The n-type CBIRD was characterized in terms of performance and thermal stability. The experimentally measured NE delta T of the 8.8 micron cutoff n-CBIRD FPA was 18.6 mK with 300 K background and f/2 cold stop at 78K FPA operating temperature. The horizontal and vertical MTFs of this pixel fully delineated CBIRD FPA at Nyquist frequency are 49% and 52%, respectively.

  2. Modulation transfer function of infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Gunapala, S. D.; Rafol, S. B.; Ting, D. Z.; Soibel, A.; Hill, C. J.; Khoshakhlagh, A.; Liu, J. K.; Mumolo, J. M.; Keo, S. A.; Höglund, L.; Luong, E. M.

    2015-09-01

    Modulation transfer function (MTF) is the ability of an imaging system to faithfully image a given object. The MTF of an imaging system quantifies the ability of the system to resolve or transfer spatial frequencies. In this presentation we will discuss the detail MTF measurements of 1024x1024 pixels mid-wavelength and long-wavelength quantum well infrared photodetector, and 320x256 pixels long-wavelength InAs/GaSb superlattice infrared focal plane arrays (FPAs). Long wavelength Complementary Barrier Infrared Detector (CBIRD) based on InAs/GaSb superlattice material is hybridized to recently designed and fabricated 320x256 pixel format ROIC. The n-type CBIRD was characterized in terms of performance and thermal stability. The experimentally measured NEΔT of the 8.8μm cutoff n-CBIRD FPA was 18.6 mK with 300 K background and f/2 cold stop at 78K FPA operating temperature. The horizontal and vertical MTFs of this pixel fully delineated CBIRD FPA at Nyquist frequency are 49% and 52%, respectively.

  3. High Sensitivity Long-Wavelength Infrared QWIP Focal Plane Array Based Instrument for Remote Sensing of Icy Satellites

    NASA Technical Reports Server (NTRS)

    Gunapala, S.; Bandara, S.; Ivanov, A.

    2003-01-01

    GaAs based Quantum Well Infrared Photodetector (QWIP) technology has shown remarkable success in advancing low cost, highly uniform, high-operability, large format multi-color focal plane arrays. QWIPs afford greater flexibility than the usual extrinsically doped semiconductor IR detectors. The wavelength of the peak response and cutoff can be continuously tailored over a range wide enough to enable light detection at any wavelength range between 6 and 20 micron. The spectral band-width of these detectors can be tuned from narrow (Deltalambda/lambda is approximately 10%) to wide (Deltalambda/lambda is approximately 40%) allowing various applications. Furthermore, QWIPs offer low cost per pixel and highly uniform large format focal plane arrays due to mature GaAs/AlGaAs growth and processing technologies. The other advantages of GaAs/AlGaAs based QWIPS are higher yield, lower l/f noise and radiation hardness (1.5 Mrad). In this presentation, we will discuss our recent demonstrations of 640x512 pixel narrow-band, broad-band, multi-band focal plane arrays, and the current status of the development of 1024x1024 pixel long-wavelength infrared QWIP focal plane arrays.

  4. High Sensitivity Long-Wavelength Infrared QWIP Focal Plane Array Based Instrument for Remote Sensing of Icy Satellites

    NASA Technical Reports Server (NTRS)

    Gunapala, S.; Bandara, S.; Ivanov, A.

    2003-01-01

    GaAs based Quantum Well Infrared Photodetector (QWIP) technology has shown remarkable success in advancing low cost, highly uniform, high-operability, large format multi-color focal plane arrays. QWIPs afford greater flexibility than the usual extrinsically doped semiconductor IR detectors. The wavelength of the peak response and cutoff can be continuously tailored over a range wide enough to enable light detection at any wavelength range between 6 and 20 micron. The spectral band-width of these detectors can be tuned from narrow (Deltalambda/lambda is approximately 10%) to wide (Deltalambda/lambda is approximately 40%) allowing various applications. Furthermore, QWIPs offer low cost per pixel and highly uniform large format focal plane arrays due to mature GaAs/AlGaAs growth and processing technologies. The other advantages of GaAs/AlGaAs based QWIPS are higher yield, lower l/f noise and radiation hardness (1.5 Mrad). In this presentation, we will discuss our recent demonstrations of 640x512 pixel narrow-band, broad-band, multi-band focal plane arrays, and the current status of the development of 1024x1024 pixel long-wavelength infrared QWIP focal plane arrays.

  5. Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array

    NASA Technical Reports Server (NTRS)

    Halama, G.; McAdoo, J.; Liu, H.

    1998-01-01

    To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

  6. Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array

    NASA Technical Reports Server (NTRS)

    Halama, G.; McAdoo, J.; Liu, H.

    1998-01-01

    To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

  7. Superlattice Barrier Infrared Detector Development at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Ting, David Z.; Soibel, Alexander; Rafol, Sir B.; Nguyen, Jean; Hoglund, Linda; Khoshakhlagh, Arezou; Keo, Sam A.; Liu, John K.; Mumolo, Jason M.

    2011-01-01

    We report recent efforts in achieving state-of-the-art performance in type-II superlattice based infrared photodetectors using the barrier infrared detector architecture. We used photoluminescence measurements for evaluating detector material and studied the influence of the material quality on the intensity of the photoluminescence. We performed direct noise measurements of the superlattice detectors and demonstrated that while intrinsic 1/f noise is absent in superlattice heterodiode, side-wall leakage current can become a source of strong frequency-dependent noise. We developed an effective dry etching process for these complex antimonide-based superlattices that enabled us to fabricate single pixel devices as well as large format focal plane arrays. We describe the demonstration of a 1024x1024 pixel long-wavelength infrared focal plane array based the complementary barrier infrared detector (CBIRD) design. An 11.5 micron cutoff focal plane without anti-reflection coating has yielded noise equivalent differential temperature of 53 mK at operating temperature of 80 K, with 300 K background and cold-stop. Imaging results from a recent 10 ?m cutoff focal plane array are also presented.

  8. High-performance visible/UV CCD focal plane technology for spacebased applications

    NASA Technical Reports Server (NTRS)

    Burke, B. E.; Mountain, R. W.; Gregory, J. A.; Huang, J. C. M.; Cooper, M. J.; Savoye, E. D.; Kosicki, B. B.

    1993-01-01

    We describe recent technology developments aimed at large CCD imagers for space based applications in the visible and UV. Some of the principal areas of effort include work on reducing device degradation in the natural space-radiation environment, improvements in quantum efficiency in the visible and UV, and larger-device formats. One of the most serious hazards for space based CCD's operating at low signal levels is the displacement damage resulting from bombardment by energetic protons. Such damage degrades charge-transfer efficiency and increases dark current. We have achieved improved hardness to proton-induced displacement damage by selective ion implants into the CCD channel and by reduced temperature of operation. To attain high quantum efficiency across the visible and UV we have developed a technology for back-illuminated CCD's. With suitable antireflection (AR) coatings such devices have quantum efficiencies near 90 percent in the 500-700-nm band. In the UV band from 200 to 400 nm, where it is difficult to find coatings that are sufficiently transparent and can provide good matching to the high refractive index of silicon, we have been able to substantially increase the quantum efficiency using a thin film of HfO2 as an AR coating. These technology efforts were applied to a 420 x 420-pixel frame-transfer imager, and future work will be extended to a 1024 x 1024-pixel device now under development.

  9. High-performance visible/UV CCD focal plane technology for spacebased applications

    NASA Technical Reports Server (NTRS)

    Burke, B. E.; Mountain, R. W.; Gregory, J. A.; Huang, J. C. M.; Cooper, M. J.; Savoye, E. D.; Kosicki, B. B.

    1993-01-01

    We describe recent technology developments aimed at large CCD imagers for space based applications in the visible and UV. Some of the principal areas of effort include work on reducing device degradation in the natural space-radiation environment, improvements in quantum efficiency in the visible and UV, and larger-device formats. One of the most serious hazards for space based CCD's operating at low signal levels is the displacement damage resulting from bombardment by energetic protons. Such damage degrades charge-transfer efficiency and increases dark current. We have achieved improved hardness to proton-induced displacement damage by selective ion implants into the CCD channel and by reduced temperature of operation. To attain high quantum efficiency across the visible and UV we have developed a technology for back-illuminated CCD's. With suitable antireflection (AR) coatings such devices have quantum efficiencies near 90 percent in the 500-700-nm band. In the UV band from 200 to 400 nm, where it is difficult to find coatings that are sufficiently transparent and can provide good matching to the high refractive index of silicon, we have been able to substantially increase the quantum efficiency using a thin film of HfO2 as an AR coating. These technology efforts were applied to a 420 x 420-pixel frame-transfer imager, and future work will be extended to a 1024 x 1024-pixel device now under development.

  10. Serial Pixel Analog-to-Digital Converter

    SciTech Connect

    Larson, E D

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and “one-hot” counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  11. ATLAS IBL Pixel Upgrade

    NASA Astrophysics Data System (ADS)

    La Rosa, A.; Atlas Ibl Collaboration

    2011-06-01

    The upgrade for ATLAS detector will undergo different phases towards super-LHC. The first upgrade for the Pixel detector will consist of the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine (LHC phase-I upgrade). The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of 3.3 cm. The IBL will require the development of several new technologies to cope with increase of radiation or pixel occupancy and also to improve the physics performance which will be achieved by reducing the pixel size and of the material budget. Three different promising sensor technologies (planar-Si, 3D-Si and diamond) are currently under investigation for the pixel detector. An overview of the project with particular emphasis on the pixel module is presented in this paper.

  12. Bad pixel mapping

    NASA Astrophysics Data System (ADS)

    Smith, Roger M.; Hale, David; Wizinowich, Peter

    2014-07-01

    Bad pixels are generally treated as a loss of useable area and then excluded from averaged performance metrics. The definition and detection of "bad pixels" or "cosmetic defects" are seldom discussed, perhaps because they are considered self-evident or of minor consequence for any scientific grade detector, however the ramifications can be more serious than generally appreciated. While the definition of pixel performance is generally understood, the classification of pixels as useable is highly application-specific, as are the consequences of ignoring or interpolating over such pixels. CMOS sensors (including NIR detectors) exhibit less compact distributions of pixel properties than CCDs. The extended tails in these distributions result in a steeper increase in bad pixel counts as performance thresholds are tightened which comes as a surprise to many users. To illustrate how some applications are much more sensitive to bad pixels than others, we present a bad pixel mapping exercise for the Teledyne H2RG used as the NIR tip-tilt sensor in the Keck-1 Adaptive Optics system. We use this example to illustrate the wide range of metrics by which a pixel might be judged inadequate. These include pixel bump bond connectivity, vignetting, addressing faults in the mux, severe sensitivity deficiency of some pixels, non linearity, poor signal linearity, low full well, poor mean-variance linearity, excessive noise and high dark current. Some pixels appear bad by multiple metrics. We also discuss the importance of distinguishing true performance outliers from measurement errors. We note how the complexity of these issues has ramifications for sensor procurement and acceptance testing strategies.

  13. Wide Field Camera 3: A Powerful New Imager for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Kimble, Randy

    2008-01-01

    Wide Field Camera 3 (WFC3) is a powerful UV/visible/near-infrared camera in development for installation into the Hubble Space Telescope during upcoming Servicing Mission 4. WFC3 provides two imaging channels. The UVIS channel incorporates a 4096 x 4096 pixel CCD focal plane with sensitivity from 200 to 1000 nm. The IR channel features a 1024 x 1024 pixel HgCdTe focal plane covering 850 to 1700 nm. We report here on the design of the instrument, the performance of its flight detectors, results of the ground test and calibration program, and the plans for the Servicing Mission installation and checkout.

  14. The IMPACTON Project: Pole and Shape of Seven near-Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Lazzaro, Daniela; Silva, José Sergio; Rodrigues, Teresinha; Márcio Carvano, Jorge; Roig, Fernando; Souza, Roberto Pereira e.; IMPACTON Team

    2015-08-01

    The formation and evolution of Solar System small bodies, in particular those in near-Earth orbits, is a complex problem which solution strongly depends on a better knowledge of their physical properties. To contribute to the international efforts in this direction the IMPACTON project (www.on.br/IMPACTON) set up a dedicated facility in a remote region in the northeast part of Brazil, denominated Observatório Astronômico do Sertão de Itaparica (OASI - code Y28, Itacuruba).Using the 1-m telescope of the OASI we observed more of 40 NEAs during several observational runs between March 2012 and October 2014. Our observations were made using an Apogee Alta U47 CCD camera, 1024 X 1024 pixels, giving a 5.9 x 5.9 arcmin field, and using an R Johnson filter.Standard reduction procedures were applied and relative magnitudes were used to obtain lightcurves for the observed asteroids. The application of the inversion of method developed by Kaasalainen and Torppa (2001) and Kaasalainen et al. (2001) allowed us to derive the rotational period for 14 NEAs and, for 7 of these, also the pole direction and the shape. The implications of the obtained results will be discussed.

  15. The AstroBiology Explorer (ABE) MIDEX Mission Concept: Identifying Organic Molecules in Space

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Sandford, Scott; Allamandola, Louis; Bregman, Jesse; Cohen, Martin; Cruikshank, Dale; Greene, Thomas; Hudgins, Douglas; Kwok, Sun; Lord, Steven; hide

    2002-01-01

    The Astrobiology Explorer (ABE) is a MIDEX mission concept, currently under Concept Phase A study at NASA's Ames Research Center in collaboration with Ball Aerospace & Technologies, Corp., and managed by NASA's Jet Propulsion Laboratory. ABE will conduct infrared spectroscopic observations to address important problems in astrobiology, astrochemistry, and astrophysics. The core observational program would make fundamental scientific progress in understanding the distribution, identity, and evolution of ices and organic matter in dense molecular clouds, young forming stellar systems, stellar outflows, the general diffuse ISM, HII regions, Solar System bodies, and external galaxies. The ABE instrument concept includes a 0.6 m aperture Ritchey-Chretien telescope and three moderate resolution (R = 2000-3000) spectrometers together covering the 2.5-20 micron spectral region. Large format (1024 x 1024 pixel) IR detector arrays will allow each spectrometer to cover an entire octave of spectral range per exposure without any moving parts. The telescope will be cooled below 50 K by a cryogenic dewar shielded by a sunshade. The detectors will be cooled to approx. 7.5 K by a solid hydrogen cryostat. The optimum orbital configuration for achieving the scientific objectives of the ABE mission is a low background, 1 AU Earth driftaway orbit requiring a Delta II launch vehicle. This configuration provides a low thermal background and allows adequate communications bandwidth and good access to the entire sky over the approx. 1.5 year mission lifetime.

  16. The AstroBiology Explorer (ABE) MIDEX Mission Concept

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Sandford, Scott; Cox, Sylvia; Ellis, Benton; Gallagher, Dennis; Gautier, Nick; Greene, Thomas; McCreight, Craig; Mills, Gary; Purcell, William; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    The Astrobiology Explorer (ABE) is a MIDEX mission concept under study at NASA's Ames Research Center in collaboration with Ball Aerospace & Technologies, Corp. ABE will conduct IR spectroscopic observations to address important problems in astrobiology, astrochemistry, and astrophysics. The core observational program would make fundamental scientific progress in understanding the distribution, identity, and evolution of ices and organic matter in dense molecular clouds, young forming stellar systems, stellar outflows, the general diffuse ISM, HII regions, Solar System bodies, and external galaxies. The ABE instrument concept includes a 0.6 m aperture Cassegrain telescope and two moderate resolution (R = 2000-3000) spectrographs covering the 2.5-16 micron spectral region. Large format (1024x 1024 pixel or larger) IR detector arrays and bandpass filters will allow each spectrograph to cover an entire octave of spectral range or more per exposure without any moving parts. The telescope will be cooled below 50K by a cryogenic dewar shielded by a sunshade. The detectors will be cooled to approximately 8K. The optimum orbital configuration for achieving the scientific objectives of the ABE mission is a low background, 1 AU Earth driftaway orbit requiring a Delta II launch vehicle. This configuration provides a low thermal background and allows adequate communications bandwidth and good access to the entire sky over the approximate 1-2 year mission lifetime.

  17. Microangiography system for investigation of metabolic syndrome in rat model using synchrotron radiation.

    PubMed

    Umetani, Keiji; Fukushima, Kazuhito; Sugimura, Kazuro

    2008-01-01

    Metabolic syndrome refers to a clustering of cardiovascular disease risk factors. We investigated the characteristics of vascular endothelial function in coronary arteries of rats using a microangiography technique. For this study, we developed a microangiography system using a real-time imaging system and a third generation synchrotron radiation source at SPring-8. An X-ray direct-conversion type detector with 6-mum spatial resolution was used for real-time biomedical imaging. For synchrotron radiation radiography, a long source-to-object distance and a small source spot can produce high-resolution images. Microangiographic images were obtained without image blurring and were stored in a digital frame memory system at a maximum speed of 30 frame/s with a 1024 x 1024-pixel, 10-bit format. The vasorelaxation response in the coronary arteries was determined using coronary microangiography of ex vivo beating hearts for evaluating vascular endothelial dysfunction in metabolic syndrome. In imaging experiments, the small coronary arteries were visualized after iodine contrast agent injection into the coronary artery. We assessed the magnitude of coronary artery vasorelaxation before and after administration of drugs that modulate endothelial control of the coronary arteries in the rat model.

  18. High-resolution digital movies of emerging flux and horizontal flows in active regions on the sun

    NASA Technical Reports Server (NTRS)

    Topka, K.; Ferguson, S.; Frank, Z.; Tarbell, T.; Title, A.

    1988-01-01

    High-resolution observations of active regions in many wavelength bands obtained at the Vacuum Tower Telescope of NSO/Sunspot (Sacramento Peak) are presented. The SOUP tunable filter, HRSO 1024 x 1024 CCD camera, and a sunspot tracker for image stabilization were used. Subarrays of 512 x 512 pixels were processed digitally and recorded on videodisk in movie format. The movies with 0.5 to 1 arcsecond resolution of the following simultaneous observations were shown: green continuum, longitudinal magnetogram, Doppler velocity, Fe I 5576 A line center, H alpha wings, and H alpha line center. The best set of movies show a 90 x 90 arcsecond field-of-view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Flux emergence is most easily discovered in line center movies: an elongated dark feature appears first, followed soon after by bright points at one or both ends. A brief, strong upflow is seen when the dark feature first appears; downflow in the bright points persists much longer. The magnetic flux appears to increase gradually over this extended period. Some of the flux emergence events were studied in detail, with measurements of horizontal and vertical velocities and magnetic flux versus time within one footpoint of the loop.

  19. The AstroBiology Explorer (ABE) MIDEX Mission Concept

    NASA Technical Reports Server (NTRS)

    Ennico, Kimberly; Sandford, Scott; Cox, Sylvia; Ellis, Benton; Gallagher, Dennis; Gautier, Nick; Greene, Thomas; McCreight, Craig; Mills, Gary; Purcell, William; hide

    2001-01-01

    The Astrobiology Explorer (ABE) is a MIDEX mission concept under study at NASA's Ames Research Center in collaboration with Ball Aerospace & Technologies, Corp. ABE will conduct IR spectroscopic observations to address important problems in astrobiology, astrochemistry, and astrophysics. The core observational program would make fundamental scientific progress in understanding the distribution, identity, and evolution of ices and organic matter in dense molecular clouds, young forming stellar systems, stellar outflows, the general diffuse ISM, HII regions, Solar System bodies, and external galaxies. The ABE instrument concept includes a 0.6 m aperture Cassegrain telescope and two moderate resolution (R = 2000-3000) spectrographs covering the 2.5-16 micron spectral region. Large format (1024x 1024 pixel or larger) IR detector arrays and bandpass filters will allow each spectrograph to cover an entire octave of spectral range or more per exposure without any moving parts. The telescope will be cooled below 50K by a cryogenic dewar shielded by a sunshade. The detectors will be cooled to approximately 8K. The optimum orbital configuration for achieving the scientific objectives of the ABE mission is a low background, 1 AU Earth driftaway orbit requiring a Delta II launch vehicle. This configuration provides a low thermal background and allows adequate communications bandwidth and good access to the entire sky over the approximate 1-2 year mission lifetime.

  20. The AstroBiology Explorer (ABE) MIDEX Mission Concept: Identifying Organic Molecules in Space

    NASA Astrophysics Data System (ADS)

    Ennico, Kimberly A.; Sandford, Scott; Allamandola, Louis; Bregman, Jesse D.; Cohen, Martin; Cruikshank, Dale; Greene, Thomas P.; Hudgins, Douglas; Kwok, Sun; Lord, Steven D.; Madden, Suzanne; McCreight, Craig R.; Roellig, Thomas L.; Strecker, Donald W.; Tielens, A. G. G. M.; Werner, Michael W.

    2003-03-01

    The Astrobiology Explorer (ABE) is a MIDEX mission concept, currently under Concept Phase A study at NASA's Ames Research Center in collaboration with Ball Aerospace &Technologies, Corp., and managed by NASA's Jet Propulsion Laboratory. ABE will conduct infrared spectroscopic observations to address important problems in astrobiology, astrochemistry, and astrophysics. The core observational program would make fundamental scientific progress in understanding the distribution, identity, and evolution of ices and organic matter in dense molecular clouds, young forming stellar systems, stellar outflows, the general diffuse ISM, HII regions, Solar System bodies, and external galaxies. The ABE instrument concept includes a 0.6 m aperture Ritchey-Chretien telescope and three moderate resolution (R = 2000-3000) spectrometers together covering the 2.5-20 micron spectral region. Large format (1024 x 1024 pixel) IR detector arrays will allow each spectrometer to cover an entire octave of spectral range per exposure without any moving parts. The telescope will be cooled below 50 K by a cryogenic dewar shielded by a sunshade. The detectors will be cooled to ~7.5 K by a solid hydrogen cryostat. The optimum orbital configuration for achieving the scientific objectives of the ABE mission is a low background, 1 AU Earth driftaway orbit requiring a Delta II launch vehicle. This configuration provides a low thermal background and allows adequate communications bandwidth and good access to the entire sky over the ~1.5 year mission lifetime.

  1. AstroBiology Explorer (ABE) MIDEX mission concept

    NASA Astrophysics Data System (ADS)

    Ennico, Kimberly A.; Sandford, Scott; Cox, Sylvia; Ellis, Benton; Gallagher, Dennis J.; Gautier, Nick; Greene, Thomas P.; McCreight, Craig R.; Mills, Gary; Purcell, William R.

    2002-02-01

    The Astrobiology Explorer (ABE) is a MIDEX mission concept under study at NASA's Ames Research Center in collaboration with Ball Aerospace & Technologies, Corp. ABE will conduct IR spectroscopic observations to address important problems in astrobiology, astrochemistry, and astrophysics. The core observational program would make fundamental scientific progress in understanding the distribution, identity, and evolution of ices and organic matter in dense molecular clouds, young forming stellar systems, stellar outflows, the general diffuse ISM, HII regions, Solar System bodies, and external galaxies. The ABE instrument concept includes a 0.6 m aperture Cassegrain telescope and two moderate resolution (R equals 2000-3000) spectrographs covering the 2.5-16 micron spectral region. Large format (1024x1024 pixel or larger) IR detector arrays and bandpass filters will allow each spectrograph to cover an entire octave of spectral range or more per exposure without any moving parts. The telescope will be cooled below 50 K by a cryogenic dewar shielded by a sunshade. The detectors will be cooled to ~8K. The optimum orbital configuration for achieving the scientific objectives of the ABE mission is a low background, 1 AU Earth driftaway orbit requiring a Delta II launch vehicle. This configuration provides a low thermal background and allows adequate communications bandwidth and good access to the entire sky over the ~1-2 year mission lifetime.

  2. Spatial Pattern of Biological Soil Crust with Fractal Geometry

    NASA Astrophysics Data System (ADS)

    Ospina, Abelardo; Florentino, Adriana; Tarquis, Ana M.

    2015-04-01

    Soil surface characteristics are subjected to changes driven by several interactions between water, air, biotic and abiotic components. One of the examples of such interactions is provided through biological soil crusts (BSC) in arid and semi-arid environments. BSC are communities composed of cyanobacteria, fungi, mosses, lichens, algae and liverworts covering the soil surface and play an important role in ecosystem functioning. The characteristics and formation of these BSC influence the soil hydrological balance, control the mass of eroded sediment, increase stability of soil surface, and influence plant productivity through the modification of nitrogen and carbon cycle. This study focus on characterize the spatial arrangements of the BSC based on image analysis and fractal concepts. To this end, RGB images of different types of biological soil crust where taken, each image corresponding to an area of 3.6 cm2 with a resolution of 1024x1024 pixels. For each image and channel, mass dimension and entropy were calculated. Preliminary results indicate that fractal methods are useful to describe changes associated to different types of BSC. Further research is necessary to apply these methodologies to several situations.

  3. Direct formation of nano-pillar arrays by phase separation of polymer blend for the enhanced out-coupling of organic light emitting diodes with low pixel blurring.

    PubMed

    Lee, Cholho; Han, Kyung-Hoon; Kim, Kwon-Hyeon; Kim, Jang-Joo

    2016-03-21

    We have demonstrated a simple and efficient method to fabricate OLEDs with enhanced out-coupling efficiencies and with low pixel blurring by inserting nano-pillar arrays prepared through the lateral phase separation of two immiscible polymers in a blend film. By selecting a proper solvent for the polymer and controlling the composition of the polymer blend, the nano-pillar arrays were formed directly after spin-coating of the polymer blend and selective removal of one phase, needing no complicated processes such as nano-imprint lithography. Pattern size and distribution were easily controlled by changing the composition and thickness of the polymer blend film. Phosphorescent OLEDs using the internal light extraction layer containing the nano-pillar arrays showed a 30% enhancement of the power efficiency, no spectral variation with the viewing angle, and only a small increment in pixel blurring. With these advantages, this newly developed method can be adopted for the commercial fabrication process of OLEDs for lighting and display applications.

  4. High density pixel array

    NASA Technical Reports Server (NTRS)

    Wiener-Avnear, Eliezer (Inventor); McFall, James Earl (Inventor)

    2004-01-01

    A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

  5. Development of large CCD arrays with enhanced UV performance

    NASA Technical Reports Server (NTRS)

    Varian, Richard H.; Schaefer, A. Russell; Cover, John; Janesick, James R.; Bredthauer, Richard

    1989-01-01

    A development status evaluation is presented for proprietary UV-range CCDs for military and scientific applications requiring pixel sizes in the 18-micron range. The most recent developments in UV/X-ray responsive detectors have their bases in the backside illumination of multipinned phase (MPP) 1024 x 1024 CCD arrays, as well as in the initial exploration of open-pinned phase (OPP) techniques. The frontside performance of both MPP and OPP devices is noted to be excellent as well, and pinouts and mounting techniques have been defined which allow easy front-back operation comparisons. Novel backside processing techniques are being refined.

  6. Manned observations technology development, FY 1992 report

    NASA Technical Reports Server (NTRS)

    Israel, Steven

    1992-01-01

    This project evaluated the suitability of the NASA/JSC developed electronic still camera (ESC) digital image data for Earth observations from the Space Shuttle, as a first step to aid planning for Space Station Freedom. Specifically, image resolution achieved from the Space Shuttle using the current ESC system, which is configured with a Loral 15 mm x 15 mm (1024 x 1024 pixel array) CCD chip on the focal plane of a Nikon F4 camera, was compared to that of current handheld 70 mm Hasselblad 500 EL/M film cameras.

  7. Megapixel Multi-band QWIP Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Rafo, S. B.; Hill, C.; Mumolo, J.; Thang, J.; Tidrow, M.; LeVan, P. D.

    2004-01-01

    A mid-wavelength 1024x1024 pixel quantum well infrared photodetector (QW) focal plane array has been demonstrated with excellent imagery. Noise equivalent differential temperature (NETD) of 19 mK was achieved at 95K operating temperature with f/2.5 optics at 300K background. This focal plane array has shown background limited performance (BLIP) at 90K operating temperature with the same optics and background conditions. In this paper, we will discuss its performance in quantum efficiency, NETD, uniformity, and operability.

  8. Performance of the JWST/MIRI Si:As Detectors

    NASA Technical Reports Server (NTRS)

    Ressler, Michael E.; Cho, Hyung; Lee, Richard A. M.; Sukhatme, Kalyani G.; Drab, John J.; Domingo, George

    2008-01-01

    The Mid-Infrared Instrument (MIRI) is a 5 to 28 micron imager and spectrometer that is slated to fly aboard the JWST in 2013. Each of the flight arrays is a 1024x1024 pixel Si:As impurity band conductor detector array, developed by Raytheon Vision Systems. JPL, in conjunction with the MIRI science team, has selected the three flight arrays along with their spares. We briefly summarize the development of these devices, then describe the measured performance of the flight arrays along with supplemental data from sister flight-like parts.

  9. Advances in Detector Technology for Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    McCreight, Craig; Cheng, P. L. (Technical Monitor)

    1995-01-01

    Progress in semiconductor materials and processing technology has allowed the development of infrared detector arrays with unprecedented sensitivity, for imaging and spectroscopic applications in astronomy. The earlier discrete-detector approach has been replaced by large-element (up to 1024 x 1024 pixel), multiplexed devices. Progress has been made against a number of key limiting factors, such as quantum efficiency, noise, spectral response, linearity, and dark current. Future developments will focus on the need for even larger arrays, which operate at higher temperatures.

  10. Compact water-window transmission X-ray microscopy.

    PubMed

    Berglund, M; Rymell, L; Peuker, M; Wilhein, T; Hertz, H M

    2000-03-01

    We demonstrate sub-100 nm resolution water-window soft X-ray full-field transmission microscopy with a compact system. The microscope operates at lambda = 3.37 nm and is based on a 100 Hz table-top regenerative debris-free droplet-target laser-plasma X-ray source in combination with normal-incidence multilayer condenser optics for sample illumination. High-spatial-resolution imaging is performed with a 7.3% efficiency nickel zone plate and a 1024 x 1024 pixel CCD detector. Images of dry test samples are recorded with exposure times of a few minutes and show features smaller than 60 nm.

  11. Automated recognition and characterization of solar active regions based on the SOHO/MDI images

    NASA Technical Reports Server (NTRS)

    Pap, J. M.; Turmon, M.; Mukhtar, S.; Bogart, R.; Ulrich, R.; Froehlich, C.; Wehrli, C.

    1997-01-01

    The first results of a new method to identify and characterize the various surface structures on the sun, which may contribute to the changes in solar total and spectral irradiance, are shown. The full disk magnetograms (1024 x 1024 pixels) of the Michelson Doppler Imager (MDI) experiment onboard SOHO are analyzed. Use of a Bayesian inference scheme allows objective, uniform, automated processing of a long sequence of images. The main goal is to identify the solar magnetic features causing irradiance changes. The results presented are based on a pilot time interval of August 1996.

  12. Early science from the Pan-STARRS1 Optical Galaxy Survey (POGS): Maps of stellar mass and star formation rate surface density obtained from distributed-computing pixel-SED fitting

    NASA Astrophysics Data System (ADS)

    Thilker, David A.; Vinsen, K.; Galaxy Properties Key Project, PS1

    2014-01-01

    To measure resolved galactic physical properties unbiased by the mask of recent star formation and dust features, we are conducting a citizen-scientist enabled nearby galaxy survey based on the unprecedented optical (g,r,i,z,y) imaging from Pan-STARRS1 (PS1). The PS1 Optical Galaxy Survey (POGS) covers 3π steradians (75% of the sky), about twice the footprint of SDSS. Whenever possible we also incorporate ancillary multi-wavelength image data from the ultraviolet (GALEX) and infrared (WISE, Spitzer) spectral regimes. For each cataloged nearby galaxy with a reliable redshift estimate of z < 0.05 - 0.1 (dependent on donated CPU power), publicly-distributed computing is being harnessed to enable pixel-by-pixel spectral energy distribution (SED) fitting, which in turn provides maps of key physical parameters such as the local stellar mass surface density, crude star formation history, and dust attenuation. With pixel SED fitting output we will then constrain parametric models of galaxy structure in a more meaningful way than ordinarily achieved. In particular, we will fit multi-component (e.g. bulge, bar, disk) galaxy models directly to the distribution of stellar mass rather than surface brightness in a single band, which is often locally biased. We will also compute non-parametric measures of morphology such as concentration, asymmetry using the POGS stellar mass and SFR surface density images. We anticipate studying how galactic substructures evolve by comparing our results with simulations and against more distant imaging surveys, some of which which will also be processed in the POGS pipeline. The reliance of our survey on citizen-scientist volunteers provides a world-wide opportunity for education. We developed an interactive interface which highlights the science being produced by each volunteer’s own CPU cycles. The POGS project has already proven popular amongst the public, attracting about 5000 volunteers with nearly 12,000 participating computers, and is

  13. Fiber pixelated image database

    NASA Astrophysics Data System (ADS)

    Shinde, Anant; Perinchery, Sandeep Menon; Matham, Murukeshan Vadakke

    2016-08-01

    Imaging of physically inaccessible parts of the body such as the colon at micron-level resolution is highly important in diagnostic medical imaging. Though flexible endoscopes based on the imaging fiber bundle are used for such diagnostic procedures, their inherent honeycomb-like structure creates fiber pixelation effects. This impedes the observer from perceiving the information from an image captured and hinders the direct use of image processing and machine intelligence techniques on the recorded signal. Significant efforts have been made by researchers in the recent past in the development and implementation of pixelation removal techniques. However, researchers have often used their own set of images without making source data available which subdued their usage and adaptability universally. A database of pixelated images is the current requirement to meet the growing diagnostic needs in the healthcare arena. An innovative fiber pixelated image database is presented, which consists of pixelated images that are synthetically generated and experimentally acquired. Sample space encompasses test patterns of different scales, sizes, and shapes. It is envisaged that this proposed database will alleviate the current limitations associated with relevant research and development and would be of great help for researchers working on comb structure removal algorithms.

  14. Selecting Pixels for Kepler Downlink

    NASA Technical Reports Server (NTRS)

    Bryson, Stephen T.; Jenkins, Jon M.; Klaus, Todd C.; Cote, Miles T.; Quintana, Elisa V.; Hall, Jennifer R.; Ibrahim, Khadeejah; Chandrasekaran, Hema; Caldwell, Douglas A.; Van Cleve, Jeffrey E.; hide

    2010-01-01

    The Kepler mission monitors > 100,000 stellar targets using 42 2200 1024 pixel CCDs. Bandwidth constraints prevent the downlink of all 96 million pixels per 30-minute cadence, so the Kepler spacecraft downlinks a specified collection of pixels for each target. These pixels are selected by considering the object brightness, background and the signal-to-noise of each pixel, and are optimized to maximize the signal-to-noise ratio of the target. This paper describes pixel selection, creation of spacecraft apertures that efficiently capture selected pixels, and aperture assignment to a target. Diagnostic apertures, short-cadence targets and custom specified shapes are discussed.

  15. Towards Dualband Megapixel QWIP Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Hill, C. J.; Rafol, S. B.; Salazar, D.; Woolaway, J.; LeVan, P. D.; Tidrow, M. Z.

    2006-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024 x 1024 pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NEDT) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NEDT of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In addition, we have demonstrated MWIR and LWIR pixel co-registered simultaneously readable dualband QWIP focal plane arrays. In this paper, we will discuss the performance in terms of quantum efficiency, NEDT, uniformity, operability, and modulation transfer functions of the 1024 x 1024 pixel arrays and the progress of dualband QWIP focal plane array development work.

  16. Full-disk magnetograms obtained with a Na magneto-optical filter at the Mount Wilson Observatory

    NASA Technical Reports Server (NTRS)

    Rhodes, Edward J., Jr.; Cacciani, Alessandro; Garneau, Glenn; Misch, Tony; Progovac, Dusan; Shieber, Tom; Tomczyk, Steve; Ulrich, Roger K.

    1988-01-01

    The first full-disk magnetograms to be obtained with the Na magneto-optical filter (MOF) which is located at the 60 foot solar tower of the Mount Wilson Observatory are presented. This MOF was employed as a longitudinal magnetograph on June 18, 19, and July 1, 1987. On those three days the MOF was combined with a large format (1024 x 1024 pixel) virtual phase change coupled device camera and a high-speed data acquisition system. The combined system was used to record both line-of-sight magnetograms and Dopplergrams which covered the entire visible solar hemisphere. The pixel size of these magnetograms and Dopplergrams was 2.3 arcseconds. On each of the three days a time series of nine pairs of magnetograms and Dopplergrams was obtained at the rate of one pair every two minutes. On the same three day longitudinal magnetograms have one arcsecond pixels were obtained with the vacuum telescope at Kitt Peak. The MOF and vacuum tower magnetograms were compared at both the JPL Multi-Mission Image Processing Laboratory and at USC and have found the two sets of images to be well correlated both in spatial distribution and strength of the measured magnetic field. The simultaneously-obtained MOF Dopplergrams to remove the crosstalk which was present between the Doppler and Zeeman shifts of the NaD lines from the magnetograms from all three days and will also describe recent improvements to the system which allowed the obtaining of full-disk magnetograms as rapidly as one every 25 seconds.

  17. Pixel-to-Pixel Flat Field Changes on the WFC

    NASA Astrophysics Data System (ADS)

    Gilliland, R. L.; Bohlin, R.

    2007-01-01

    The pixel-to-pixel flat field changes noted by Bohlin and Mack (2005) for the WFC are further quantified. During each period between anneals, a population of pixels with lowered sensitivity develops which is largely reset by the next anneal. The sensitivity deficits are twice as large in the blue as in the red. The pixels with lowered sensitivity appear to be a unique set each anneal cycle, rather than a subset that ‘telegraph’ on and off. The low QE pixels recover 90% of their losses on a time scale of a few monthly anneals, but never return fully. Some evidence for spontaneous recovery of the low QE pixels between anneal cycles is developed, but is not conclusive. The number of low pixels would become a large source of error in the absence of performing anneals on a frequent basis. Prior to cooldown in July 2006, the flat field changes that arise continuously within anneal cycles are larger than cumulative persistent changes in the pixel-to-pixel flats. The pre-cooldown reference flat field remained excellent. Post-cooldown, the number of persistent deviant pixels, although still modest in number, may have reached a level justifying delivery of new pixel-to-pixel flats, although providing such will require acquisition of further data.

  18. Nonlinear Pixel Replacement Estimation.

    DTIC Science & Technology

    1986-04-01

    Systems Command _________ _______________________ _____ 6e ADDRESS IC,,, Sra,. and ZIP Co~ de , 10 SOURCE Of FUNDING NUMBERS% RORMELEMENT NO PROJECT NO... de - scribed, this method does not replace array elements with computed values, but rather replaces them with one of the nine original pixel values. The...8217, gmx . NOISE PStd dev=’. sd call exit end include ’mathfunc For/nolist’ C-9 c biweighted 3xZ3 filter compute weighted mean from input iara subroutine

  19. Gallium arsenide pixel detectors

    NASA Astrophysics Data System (ADS)

    Bates, R.; Campbell, M.; Cantatore, E.; D'Auria, S.; da Vià, C.; del Papa, C.; Heijne, E. M.; Middelkamp, P.; O'Shea, V.; Raine, C.; Ropotar, I.; Scharfetter, L.; Smith, K.; Snoeys, W.

    1998-02-01

    GaAs detectors can be fabricated with bidimensional single-sided electrode segmentation. They have been successfully bonded using flip-chip technology to the Omega-3 silicon read-out chip. We present here the design features of the GaAs pixel detectors and results from a test performed at the CERN SpS with a 120 GeV π- beam. The detection efficiency was 99.2% with a nominal threshold of 5000 e -.

  20. Serial pixel analog-to-digital converter (ADC)

    NASA Astrophysics Data System (ADS)

    Larson, Eric D.

    2010-02-01

    This method reduces the data path from the counter to the pixel register of the analog-to-digital converter (ADC) from as many as 10 bits to a single bit. The reduction in data path width is accomplished by using a coded serial data stream similar to a pseudo random number (PRN) generator. The resulting encoded pixel data is then decoded into a standard hexadecimal format before storage. The high-speed serial pixel ADC concept is based on the single-slope integrating pixel ADC architecture. Previous work has described a massively parallel pixel readout of a similar architecture. The serial ADC connection is similar to the state-of-the art method with the exception that the pixel ADC register is a shift register and the data path is a single bit. A state-of-the-art individual-pixel ADC uses a single-slope charge integration converter architecture with integral registers and "one-hot" counters. This implies that parallel data bits are routed among the counter and the individual on-chip pixel ADC registers. The data path bit-width to the pixel is therefore equivalent to the pixel ADC bit resolution.

  1. The kilopixel array pathfinder project (KAPPa), a 16-pixel integrated heterodyne focal plane array: characterization of the single pixel prototype

    NASA Astrophysics Data System (ADS)

    Wheeler, Caleb H.; Groppi, Christopher E.; Mani, Hamdi; McGarey, Patrick; Kuenzi, Linda; Weinreb, Sander; Russell, Damon S.; Kooi, Jacob W.; Lichtenberger, Arthur W.; Walker, Christopher K.; Kulesa, Craig

    2014-07-01

    We report on the laboratory testing of KAPPa, a 16-pixel proof-of-concept array to enable the creation THz imaging spectrometer with ~1000 pixels. Creating an array an order of magnitude larger than the existing state of the art of 64 pixels requires a simple and robust design as well as improvements to mixer selection, testing, and assembly. Our testing employs a single pixel test bench where a novel 2D array architecture is tested. The minimum size of the footprint is dictated by the diameter of the drilled feedhorn aperture. In the adjoining detector block, a 6mm × 6mm footprint houses the SIS mixer, LNA, matching and bias networks, and permanent magnet. We present an initial characterization of the single pixel prototype using a computer controlled test bench to determine Y-factors for a parameter space of LO power, LO frequency, IF bandwidth, magnet field strength, and SIS bias voltage. To reduce the need to replace poorly preforming pixels that are already mounted in a large format array, we show techniques to improve SIS mixer selection prior to mounting in the detector block. The 2D integrated 16-pixel array design has been evolved as we investigate the properties of the single pixel prototype. Carful design of the prototype has allowed for rapid translation of single pixel design improvements to be easily incorporated into the 16-pixel model.

  2. Pixelated neutron image plates

    NASA Astrophysics Data System (ADS)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  3. Entoto Twining Telescopes: first robotic facilities in East Africa for astronomy research

    NASA Astrophysics Data System (ADS)

    Belay Tessema, Solomon

    2015-08-01

    The robotic 1-m alt-azimuthal (Astelco Systems 1000-5950 (ESSS)) twining telescopes, based on the Entoto mount of Addis Ababa, which of each has primary mirror supported by Active-Optics actuators and two Nasmyth focuses. These telescopes has a diverse instrument with four CCDs: SBIG STL 11000M (4000 x 2672, 9 μm), SBIG STL 1001E (1024 x 1024, 24 μm), ANDOR iXon3-888 (1024 x 1024, 13 μm) and FLI PL 4301E-1 (2048 x 2048, 24 μm), as well as with Fibre Linked Echelle Astronomical Spectrograph (FLECHAS) with spectral range from 389nm to 762nm on CCD detectors of 2048x2048 pixels, 15 μm square pixel size, and Spectral peak resolution R (λ/Δλ) > 37000. These telescopes are used for observations of the main distance indicators - Cepheids and RR Lyrae stars - to study the structure, variable stars, time photometry and spectra of supernovae, X-ray binaries, Light Curves, exo-planets, kinematics of the disk and halo of our Galaxy and etc. We outline here our scientific goals and present the results of our preliminary optical design studies.

  4. The ALICE Pixel Detector

    NASA Astrophysics Data System (ADS)

    Mercado-Perez, Jorge

    2002-07-01

    The present document is a brief summary of the performed activities during the 2001 Summer Student Programme at CERN under the Scientific Summer at Foreign Laboratories Program organized by the Particles and Fields Division of the Mexican Physical Society (Sociedad Mexicana de Fisica). In this case, the activities were related with the ALICE Pixel Group of the EP-AIT Division, under the supervision of Jeroen van Hunen, research fellow in this group. First, I give an introduction and overview to the ALICE experiment; followed by a description of wafer probing. A brief summary of the test beam that we had from July 13th to July 25th is given as well.

  5. Analog pixel array detectors.

    PubMed

    Ercan, A; Tate, M W; Gruner, S M

    2006-03-01

    X-ray pixel array detectors (PADs) are generally thought of as either digital photon counters (DPADs) or X-ray analog-integrating pixel array detectors (APADs). Experiences with APADs, which are especially well suited for X-ray imaging experiments where transient or high instantaneous flux events must be recorded, are reported. The design, characterization and experimental applications of several APAD designs developed at Cornell University are discussed. The simplest design is a ;flash' architecture, wherein successive integrated X-ray images, as short as several hundred nanoseconds in duration, are stored in the detector chips for later off-chip digitization. Radiography experiments using a prototype flash APAD are summarized. Another design has been implemented that combines flash capability with the ability to continuously stream X-ray images at slower (e.g. milliseconds) rates. Progress is described towards radiation-hardened APADs that can be tiled to cover a large area. A mixed-mode PAD, design by combining many of the attractive features of both APADs and DPADs, is also described.

  6. Imaging properties of pixellated scintillators with deep pixels

    PubMed Central

    Barber, H. Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P.; Furenlid, Lars R.; Miller, Brian W.; Parkhurst, Philip; Nagarkar, Vivek V.

    2015-01-01

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10×10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm × 1mm × 20 mm pixels) made by Proteus, Inc. with similar 10×10 arrays of LSO:Ce and BGO (1mm × 1mm × 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10×10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors. PMID:26236070

  7. Imaging properties of pixellated scintillators with deep pixels

    NASA Astrophysics Data System (ADS)

    Barber, H. Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P.; Furenlid, Lars R.; Miller, Brian W.; Parkhurst, Philip; Nagarkar, Vivek V.

    2014-09-01

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10x10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm x 1mm x 20 mm pixels) made by Proteus, Inc. with similar 10x10 arrays of LSO:Ce and BGO (1mm x 1mm x 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10x10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of 176Lu in LSO:Ce and LYSO:Ce detectors.

  8. Imaging properties of pixellated scintillators with deep pixels.

    PubMed

    Barber, H Bradford; Fastje, David; Lemieux, Daniel; Grim, Gary P; Furenlid, Lars R; Miller, Brian W; Parkhurst, Philip; Nagarkar, Vivek V

    2014-08-17

    We have investigated the light-transport properties of scintillator arrays with long, thin pixels (deep pixels) for use in high-energy gamma-ray imaging. We compared 10×10 pixel arrays of YSO:Ce, LYSO:Ce and BGO (1mm × 1mm × 20 mm pixels) made by Proteus, Inc. with similar 10×10 arrays of LSO:Ce and BGO (1mm × 1mm × 15mm pixels) loaned to us by Saint-Gobain. The imaging and spectroscopic behaviors of these scintillator arrays are strongly affected by the choice of a reflector used as an inter-pixel spacer (3M ESR in the case of the Proteus arrays and white, diffuse-reflector for the Saint-Gobain arrays). We have constructed a 3700-pixel LYSO:Ce Prototype NIF Gamma-Ray Imager for use in diagnosing target compression in inertial confinement fusion. This system was tested at the OMEGA Laser and exhibited significant optical, inter-pixel cross-talk that was traced to the use of a single-layer of ESR film as an inter-pixel spacer. We show how the optical cross-talk can be mapped, and discuss correction procedures. We demonstrate a 10×10 YSO:Ce array as part of an iQID (formerly BazookaSPECT) imager and discuss issues related to the internal activity of (176)Lu in LSO:Ce and LYSO:Ce detectors.

  9. Pixelated gamma detector

    SciTech Connect

    Dolinsky, Sergei Ivanovich; Yanoff, Brian David; Guida, Renato; Ivan, Adrian

    2016-12-27

    A pixelated gamma detector includes a scintillator column assembly having scintillator crystals and optical transparent elements alternating along a longitudinal axis, a collimator assembly having longitudinal walls separated by collimator septum, the collimator septum spaced apart to form collimator channels, the scintillator column assembly positioned adjacent to the collimator assembly so that the respective ones of the scintillator crystal are positioned adjacent to respective ones of the collimator channels, the respective ones of the optical transparent element are positioned adjacent to respective ones of the collimator septum, and a first photosensor and a second photosensor, the first and the second photosensor each connected to an opposing end of the scintillator column assembly. A system and a method for inspecting and/or detecting defects in an interior of an object are also disclosed.

  10. Pixelation Effects in Weak Lensing

    NASA Technical Reports Server (NTRS)

    High, F. William; Rhodes, Jason; Massey, Richard; Ellis, Richard

    2007-01-01

    Weak gravitational lensing can be used to investigate both dark matter and dark energy but requires accurate measurements of the shapes of faint, distant galaxies. Such measurements are hindered by the finite resolution and pixel scale of digital cameras. We investigate the optimum choice of pixel scale for a space-based mission, using the engineering model and survey strategy of the proposed Supernova Acceleration Probe as a baseline. We do this by simulating realistic astronomical images containing a known input shear signal and then attempting to recover the signal using the Rhodes, Refregier, and Groth algorithm. We find that the quality of shear measurement is always improved by smaller pixels. However, in practice, telescopes are usually limited to a finite number of pixels and operational life span, so the total area of a survey increases with pixel size. We therefore fix the survey lifetime and the number of pixels in the focal plane while varying the pixel scale, thereby effectively varying the survey size. In a pure trade-off for image resolution versus survey area, we find that measurements of the matter power spectrum would have minimum statistical error with a pixel scale of 0.09' for a 0.14' FWHM point-spread function (PSF). The pixel scale could be increased to 0.16' if images dithered by exactly half-pixel offsets were always available. Some of our results do depend on our adopted shape measurement method and should be regarded as an upper limit: future pipelines may require smaller pixels to overcome systematic floors not yet accessible, and, in certain circumstances, measuring the shape of the PSF might be more difficult than those of galaxies. However, the relative trends in our analysis are robust, especially those of the surface density of resolved galaxies. Our approach thus provides a snapshot of potential in available technology, and a practical counterpart to analytic studies of pixelation, which necessarily assume an idealized shape

  11. How Many Pixels Does It Take to Make a Good 4"×6" Print? Pixel Count Wars Revisited

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    Digital still cameras emerged following the introduction of the Sony Mavica analog prototype camera in 1981. These early cameras produced poor image quality and did not challenge film cameras for overall quality. By 1995 digital still cameras in expensive SLR formats had 6 mega-pixels and produced high quality images (with significant image processing). In 2005 significant improvement in image quality was apparent and lower prices for digital still cameras (DSCs) started a rapid decline in film usage and film camera sells. By 2010 film usage was mostly limited to professionals and the motion picture industry. The rise of DSCs was marked by a “pixel war” where the driving feature of the cameras was the pixel count where even moderate cost, ˜120, DSCs would have 14 mega-pixels. The improvement of CMOS technology pushed this trend of lower prices and higher pixel counts. Only the single lens reflex cameras had large sensors and large pixels. The drive for smaller pixels hurt the quality aspects of the final image (sharpness, noise, speed, and exposure latitude). Only today are camera manufactures starting to reverse their course and producing DSCs with larger sensors and pixels. This paper will explore why larger pixels and sensors are key to the future of DSCs.

  12. THE KEPLER PIXEL RESPONSE FUNCTION

    SciTech Connect

    Bryson, Stephen T.; Haas, Michael R.; Dotson, Jessie L.; Koch, David G.; Borucki, William J.; Tenenbaum, Peter; Jenkins, Jon M.; Chandrasekaran, Hema; Caldwell, Douglas A.; Klaus, Todd; Gilliland, Ronald L.

    2010-04-20

    Kepler seeks to detect sequences of transits of Earth-size exoplanets orbiting solar-like stars. Such transit signals are on the order of 100 ppm. The high photometric precision demanded by Kepler requires detailed knowledge of how the Kepler pixels respond to starlight during a nominal observation. This information is provided by the Kepler pixel response function (PRF), defined as the composite of Kepler's optical point-spread function, integrated spacecraft pointing jitter during a nominal cadence and other systematic effects. To provide sub-pixel resolution, the PRF is represented as a piecewise-continuous polynomial on a sub-pixel mesh. This continuous representation allows the prediction of a star's flux value on any pixel given the star's pixel position. The advantages and difficulties of this polynomial representation are discussed, including characterization of spatial variation in the PRF and the smoothing of discontinuities between sub-pixel polynomial patches. On-orbit super-resolution measurements of the PRF across the Kepler field of view are described. Two uses of the PRF are presented: the selection of pixels for each star that maximizes the photometric signal-to-noise ratio for that star, and PRF-fitted centroids which provide robust and accurate stellar positions on the CCD, primarily used for attitude and plate scale tracking. Good knowledge of the PRF has been a critical component for the successful collection of high-precision photometry by Kepler.

  13. Small pixel infrared sensor technology

    NASA Astrophysics Data System (ADS)

    Caulfield, John; Curzan, Jon

    2017-02-01

    We report on product maturation of small pixel high definition high charge capacity 2.4 Mpixel MWIR Infrared Focal Plane Arrays. This high definition (HD) FPA utilizes a small 5 um pitch pixel size which enables near Nyquist limited sampling with by the optical system of many IR lenses. These smaller sub diffraction pitch pixels enable improved sensitivity and resolution resulting in clear, crisp high contrast imaging with excellent IFOVs even with small focal length lenses. The small pixel IR sensor allows the designer to trade off field of view, MTF, optics F/# to obtain a more compact and high performance IR sensor. This enables lower size, power and weight reductions of the entire IR Sensor System. The highly sensitive MWIR small pixel HD FPA has the capability to detect dimmer signals at longer ranges than previously demonstrated.

  14. VizieR Online Data Catalog: 17 Seyfert 1 galaxies light curves (Koshida+, 2014)

    NASA Astrophysics Data System (ADS)

    Koshida, S.; Minezaki, T.; Yoshii, Y.; Kobayashi, Y.; Sakata, Y.; Sugawara, S.; Enya, K.; Suganuma, M.; Tomita, H.; Aoki, T.; Peterson, B. A.

    2017-07-01

    Monitoring observations were conducted by using the multicolor imaging photometer (MIP) mounted on the MAGNUM telescope (Kobayashi et al. 1998SPIE.3352..120K, 1998SPIE.3354..769K). The MIP has a field of view of 1.5x1.5 arcmin2; it is capable of simultaneously obtaining images in optical (U, B, V, R, and I) and near-infrared (J, H, and K) bands by splitting the incident beam into two different detectors including an SITe CCD (1024x1024 pixels, 0.277 arcsec/pixel) and an SBRC InSb array (256x256 pixels, 0.346 arcsec/pixel). Monitoring observations with the MAGNUM telescope began in 2001-2003, although that for NGC 3516 and NGC 4593 began in 2005. We present the data obtained through 2006-2007 to include monitoring spans of three to seven yr. (2 data files).

  15. From Pixels to Planets

    NASA Technical Reports Server (NTRS)

    Brownston, Lee; Jenkins, Jon M.

    2015-01-01

    The Kepler Mission was launched in 2009 as NASAs first mission capable of finding Earth-size planets in the habitable zone of Sun-like stars. Its telescope consists of a 1.5-m primary mirror and a 0.95-m aperture. The 42 charge-coupled devices in its focal plane are read out every half hour, compressed, and then downlinked monthly. After four years, the second of four reaction wheels failed, ending the original mission. Back on earth, the Science Operations Center developed the Science Pipeline to analyze about 200,000 target stars in Keplers field of view, looking for evidence of periodic dimming suggesting that one or more planets had crossed the face of its host star. The Pipeline comprises several steps, from pixel-level calibration, through noise and artifact removal, to detection of transit-like signals and the construction of a suite of diagnostic tests to guard against false positives. The Kepler Science Pipeline consists of a pipeline infrastructure written in the Java programming language, which marshals data input to and output from MATLAB applications that are executed as external processes. The pipeline modules, which underwent continuous development and refinement even after data started arriving, employ several analytic techniques, many developed for the Kepler Project. Because of the large number of targets, the large amount of data per target and the complexity of the pipeline algorithms, the processing demands are daunting. Some pipeline modules require days to weeks to process all of their targets, even when run on NASA's 128-node Pleiades supercomputer. The software developers are still seeking ways to increase the throughput. To date, the Kepler project has discovered more than 4000 planetary candidates, of which more than 1000 have been independently confirmed or validated to be exoplanets. Funding for this mission is provided by NASAs Science Mission Directorate.

  16. MegaMIR: The Megapixel Mid-Infrared Instrument for the Large Binocular Telescope Interferometer

    NASA Technical Reports Server (NTRS)

    Mainzer, Amanda K.; Young, Erick; Hong, John; Werner, Mike; Hinz, Phil; Gorjan, Varoujan; Ressler, Michael E.

    2006-01-01

    The Megapixel Mid-infrared Instrument (MegaMIR) is a proposed Fizeau-mode camera for the Large Binocular Telescope operating at wavelengths between 5 and 28 micrometers. The camera will be used in conjunction with the Large Binocular Telescope Interferometer (LBTI), a cryogenic optical system that combines the beams from twin 8.4-m telescopes in a phase coherent manner. Unlike other interferometric systems, the co-mounted telescopes on the LBT satisfy the sine condition, providing diffraction-limited resolution over the 40" field of view of the camera. With a 22.8-m baseline, MegaMIR will yield 0.1" angular resolution, making it the highest resolution wide field imager in the thermal infrared for at least the next decade. MegaMIR will utilize a newly developed 1024 x 1024 pixel Si:As detector array that has been optimized for use at high backgrounds. This new detector is a derivative of the Wide-field Infrared Survey Explorer (WISE) low-background detector. The combination of high angular resolution and wide field imaging will be a unique scientific capability for astronomy. Key benefits will be realized in planetary science, galactic, and extra-galactic astronomy. High angular resolution is essential to disentangle highly complex sources, particularly in star formation regions and external galaxies, and MegaMIR provides this performance over a full field of view. Because of the great impact being made by space observatories like the Spitzer Space Telescope, the number of available targets for study has greatly increased in recent years, and MegaMIR will allow efficient follow up science.

  17. The AstroBiology Explorer (ABE) MIDEX Mission

    NASA Technical Reports Server (NTRS)

    Greene, Thomas; Sandford, Scott; Allamandola, Louis; Arno, Roger; Bregman, Jesse; Cox, Sylvia; Davis, Paul; Gonzales, Andrew; Hanel, Robert; Hines, Michael; hide

    2000-01-01

    The Astrobiology Explorer (ABE) is a Medium-Class Explorer (MIDEX) mission concept currently under study at NASA's Ames Research Center. ABE will conduct infrared (IR) spectroscopic observations with much better sensitivity than Infrared Space Observatory (ISO) or the Stratospheric Observatory for Infrared Astronomy program (SOFIA) in order to address outstanding astrobiologically important problems in astrochemistry as well as important astrophysical investigations. The core observational astrobiology program would make fundamental scientific progress in understanding the cosmic history of molecular carbon, the distribution of organic matter in the diffuse interstellar medium, tracing the chemical history of complex organic molecules in the interstellar medium, and the evolution of organic ices in young planetary systems. The ABE instrument concept includes a 0.5 m aperture Cassegrain telescope and a suite of three moderate resolution (R = 1000 - 4000) spectrographs which cover the entire lambda = 2.5-20 micron spectral region. Use of large format (1024 x 1024 pixel or larger) IR detector arrays will allow each spectrograph to cover an entire octave of spectral range per exposure without any moving parts. The telescope is passively cooled by a sun shade to below 65 K, and the detectors are cooled with solid H2 cryogen to approximately 8 K. ABE will be placed in an Earth-trailing one AU solar orbit by a Delta II launch vehicle. This energetically favorable orbit provides a low thermal background, affords good access to the entire sky over the one year mission lifetime, and allows adequate communications bandwidth. The spacecraft will be stabilized in three axes and will be pointed to an accuracy of approximately one arcsecond at ABE's several thousand individual scientific targets.

  18. Design and Characterization of the CCD Detector Assemblies for ICON FUV

    NASA Astrophysics Data System (ADS)

    Champagne, J.; Syrstad, E. A.; Siegmund, O.; Darling, N.; Jelinsky, S. R.; Curtis, T.

    2015-12-01

    The Far Ultraviolet Imaging Spectrograph (FUV) on the upcoming Ionospheric Connection Explorer (ICON) mission uses dual image-intensified CCD camera systems, capable of detecting individual UV photons from both spectrometer channels (135.6 and 155 nm). Incident photons are converted to visible light using a sealed tube UV converter. The converter output is coupled to the CCD active area using a bonded fiber optic taper. The CCD (Teledyne DALSA FTT1010M) is a 1024x1024 frame transfer architecture. The camera readout electronics provide video imagery to the spacecraft over a 21 bit serialized LVDS interface, nominally at 10 frames per second and in 512x512 format (2x2 pixel binning). The CCD and primary electronics assembly reside in separate thermal zones, to minimize dark current without active cooling.Engineering and flight camera systems have been assembled, integrated, and tested under both ambient pressure and thermal vacuum environments. The CCD cameras have been fully characterized with both visible light (prior to integration with the UV converter) and UV photons (following system integration). Measured parameters include camera dark current, dark signal non-uniformity, read noise, linearity, gain, pulse height distribution, dynamic range, charge transfer efficiency, resolution, relative efficiency, quantum efficiency, and full well capacity. UV characterization of the camera systems over a range of microchannel plate (MCP) voltages during thermal vacuum testing demonstrates that camera performance will meet the critical on-orbit FUV dynamic range requirements. Flight camera integration with the FUV instrument and sensor calibration is planned for Fall 2015. Camera design and full performance data for the engineering and flight model cameras will be presented.

  19. MegaMIR: The Megapixel Mid-Infrared Instrument for the Large Binocular Telescope Interferometer

    NASA Technical Reports Server (NTRS)

    Mainzer, Amanda K.; Young, Erick; Hong, John; Werner, Mike; Hinz, Phil; Gorjan, Varoujan; Ressler, Michael E.

    2006-01-01

    The Megapixel Mid-infrared Instrument (MegaMIR) is a proposed Fizeau-mode camera for the Large Binocular Telescope operating at wavelengths between 5 and 28 micrometers. The camera will be used in conjunction with the Large Binocular Telescope Interferometer (LBTI), a cryogenic optical system that combines the beams from twin 8.4-m telescopes in a phase coherent manner. Unlike other interferometric systems, the co-mounted telescopes on the LBT satisfy the sine condition, providing diffraction-limited resolution over the 40" field of view of the camera. With a 22.8-m baseline, MegaMIR will yield 0.1" angular resolution, making it the highest resolution wide field imager in the thermal infrared for at least the next decade. MegaMIR will utilize a newly developed 1024 x 1024 pixel Si:As detector array that has been optimized for use at high backgrounds. This new detector is a derivative of the Wide-field Infrared Survey Explorer (WISE) low-background detector. The combination of high angular resolution and wide field imaging will be a unique scientific capability for astronomy. Key benefits will be realized in planetary science, galactic, and extra-galactic astronomy. High angular resolution is essential to disentangle highly complex sources, particularly in star formation regions and external galaxies, and MegaMIR provides this performance over a full field of view. Because of the great impact being made by space observatories like the Spitzer Space Telescope, the number of available targets for study has greatly increased in recent years, and MegaMIR will allow efficient follow up science.

  20. Silicon-Gas Pixel Detector

    NASA Astrophysics Data System (ADS)

    Bashindzhagyan, G.; Korotkova, N.; Romaniouk, A.; Sinev, N.; Tikhomirov, V.

    2017-01-01

    The proposed Silicon-Gas Pixel Detector (SGPD) combines the advantages of Silicon and Gas-pixel detectors (GPD). 7 micron space resolution and down to 0.2 degree both angles measurements are inside 10 mm thick and very low material detector. Silicon pixels implemented directly into electronic chip structure allow to know exact time when particle crossed the detector and to use SGPD as a completely self-triggered device. Binary readout, advanced data collection and analysis on hardware level allow to obtain all the information in less than 1 microsecond and to use SGPD for the fast trigger generation.

  1. Local Pixel Bundles: Bringing the Pixels to the People

    NASA Astrophysics Data System (ADS)

    Anderson, Jay

    2014-12-01

    The automated galaxy-based alignment software package developed for the Frontier Fields program (hst2galign, see Anderson & Ogaz 2014 and http://www.stsci.edu/hst/campaigns/frontier-fields/) produces a direct mapping from the pixels of the flt frame of each science exposure into a common master frame. We can use these mappings to extract the flt-pixels in the vicinity of a source of interest and package them into a convenient "bundle". In addition to the pixels, this data bundle can also contain "meta" information that will allow users to transform positions from the flt pixels to the reference frame and vice-versa. Since the un-resampled pixels in the flt frames are the only true constraints we have on the astronomical scene, the ability to inter-relate these pixels will enable many high-precision studies, such as: point-source-fitting and deconvolution with accurate PSFs, easy exploration of different image-combining algorithms, and accurate faint-source finding and photometry. The data products introduced in this ISR are a very early attempt to provide the flt-level pixel constraints in a package that is accessible to more than the handful of experts in HST astrometry. The hope is that users in the community might begin using them and will provide feedback as to what information they might want to see in the bundles and what general analysis packages they might find useful. For that reason, this document is somewhat informally written, since I know that it will be modified and updated as the products and tools are optimized.

  2. VizieR Online Data Catalog: HD61005 SPHERE H and Ks images (Olofsson+, 2016)

    NASA Astrophysics Data System (ADS)

    Olofsson, J.; Samland, M.; Avenhaus, H.; Caceres, C.; Henning, T.; Moor, A.; Milli, J.; Canovas, H.; Quanz, S. P.; Schreiber, M. R.; Augereau, J.-C.; Bayo, A.; Bazzon, A.; Beuzit, J.-L.; Boccaletti, A.; Buenzli, E.; Casassus, S.; Chauvin, G.; Dominik, C.; Desidera, S.; Feldt, M.; Gratton, R.; Janson, M.; Lagrange, A.-M.; Langlois, M.; Lannier, J.; Maire, A.-L.; Mesa, D.; Pinte, C.; Rouan, D.; Salter, G.; Thalmann, C.; Vigan, A.

    2016-05-01

    The fits files contains the reduced ADI and DPI SPHERE observations used to produce Fig. 1 of the paper. Besides the primary card, the files consists of 6 additional ImageHDU. The first and second one contain the SPHERE IRDIS ADI H band observations and the noise map. The third and fourth contain the SPHERE IRDIS ADI Ks band observations and the corresponding noise map. Finally, the fifth and sixth ImageHDU contain the SPHERE IRDIS DPI H band data as well as the noise map. Each ADI image has 1024x1024 pixels, while the DPI images have 1800x1800 pixels. The header of the primary card contains the pixel sizes for each datasets and the wavelengths of the H and K band observations. (2 data files).

  3. Method of fabrication of display pixels driven by silicon thin film transistors

    DOEpatents

    Carey, Paul G.; Smith, Patrick M.

    1999-01-01

    Display pixels driven by silicon thin film transistors are fabricated on plastic substrates for use in active matrix displays, such as flat panel displays. The process for forming the pixels involves a prior method for forming individual silicon thin film transistors on low-temperature plastic substrates. Low-temperature substrates are generally considered as being incapable of withstanding sustained processing temperatures greater than about 200.degree. C. The pixel formation process results in a complete pixel and active matrix pixel array. A pixel (or picture element) in an active matrix display consists of a silicon thin film transistor (TFT) and a large electrode, which may control a liquid crystal light valve, an emissive material (such as a light emitting diode or LED), or some other light emitting or attenuating material. The pixels can be connected in arrays wherein rows of pixels contain common gate electrodes and columns of pixels contain common drain electrodes. The source electrode of each pixel TFT is connected to its pixel electrode, and is electrically isolated from every other circuit element in the pixel array.

  4. Sink Pixels in ACS/WFC

    NASA Astrophysics Data System (ADS)

    Ryon, J. E.; Grogin, N.

    2017-02-01

    We investigate the properties of sink pixels in the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) detector. These pixels likely contain extra charge traps and therefore appear anomalously low in images with relatively high backgrounds. We identify sink pixels in the average short (0.5-second) dark image from each monthly anneal cycle, which, since January 2015, have been post-flashed to a background of about 60 e-. Sink pixels can affect the pixels immediately above and below them in the same column, resulting in high downstream pixels and low trails of upstream pixels. We determine typical trail lengths for sink pixels of different depths at various background levels. We create a reference image, one for each anneal cycle since January 2015, that will be used to flag sink pixels and the adjacent affected pixels in science images.

  5. 12 mega-pixel, 1,000 fps visible camera with a nanowatt A/D converter at each pixel

    NASA Astrophysics Data System (ADS)

    Mandl, William

    2005-08-01

    A large format, area array, digital visible light camera was developed based on A/D conversion at each pixel. Production CMOS technology was used in the development of a monolithic front side illuminated photo diode pixel. Each pixel includes a one loop MOSAD, (Multiplexed Oversample A/D) converter, photo diode, and buffered output to support a very large array format operating at high frame rates. MOSAD is a modification of the delta sigma approach to A/D conversion. The 12 megapixel sensor consists of a 4,000X3,000 pixel array capable of up to 1,000 frames per second sample rate. To approximately fit a 35 millimeter optics format, a pixel size of 8.5 μm was selected. There are no operational amplifiers required at the pixel to perform the A/D function, thus allowing a high fill factor. With this pixel size, a 48% fill factor and 38% photo diode area was achieved. A single process run was completed yielding five 8 inch wafers each containing 27 camera die. The single poly, three metal AMIS 0.35 μm CMOS process was used in the fabrication process. Selected die were directly mounted on a specially designed carrier daughter board. Camera support electronics were designed and fabricated to allow sampling of the camera output using commercial standard Camera Link interfacing. Off the shelf 35 Millimeter optics was used to validate imaging capabilities of the sensor. Tests show that the first iteration sensor chip design works to the fundamental requirements and can image.

  6. Challenges of small-pixel infrared detectors: a review

    NASA Astrophysics Data System (ADS)

    Rogalski, A.; Martyniuk, P.; Kopytko, M.

    2016-04-01

    In the last two decades, several new concepts for improving the performance of infrared detectors have been proposed. These new concepts particularly address the drive towards the so-called high operating temperature focal plane arrays (FPAs), aiming to increase detector operating temperatures, and as a consequence reduce the cost of infrared systems. In imaging systems with the above megapixel formats, pixel dimension plays a crucial role in determining critical system attributes such as system size, weight and power consumption (SWaP). The advent of smaller pixels has also resulted in the superior spatial and temperature resolution of these systems. Optimum pixel dimensions are limited by diffraction effects from the aperture, and are in turn wavelength-dependent. In this paper, the key challenges in realizing optimum pixel dimensions in FPA design including dark current, pixel hybridization, pixel delineation, and unit cell readout capacity are outlined to achieve a sufficiently adequate modulation transfer function for the ultra-small pitches involved. Both photon and thermal detectors have been considered. Concerning infrared photon detectors, the trade-offs between two types of competing technology—HgCdTe material systems and III-V materials (mainly barrier detectors)—have been investigated.

  7. WFC3 Pixel Area Maps

    NASA Astrophysics Data System (ADS)

    Kalirai, J. S.; Cox, C.; Dressel, L.; Fruchter, A.; Hack, W.; Kozhurina-Platais, V.; Mack, J.

    2010-04-01

    We present the pixel area maps (PAMs) for the WFC3/UVIS and WFC3/IR detectors, and discuss the normalization of these images. HST processed flt images suffer from geometric distortion and therefore have pixel areas that vary on the sky. The counts (electrons) measured for a source on these images depends on the position of the source on the detector, an effect that is implicitly corrected when these images are multidrizzled into drz files. The flt images can be multiplied by the PAMs to yield correct and uniform counts for a given source irrespective of its location on the image. To ensure consistency between the count rate measured for sources in drz images and near the center of flt images, we set the normalization of the PAMs to unity at a reference pixel near the center of the UVIS mosaic and IR detector, and set the SCALE in the IDCTAB equal to the square root of the area of this reference pixel. The implications of this choice for photometric measurements are discussed.

  8. VizieR Online Data Catalog: Deep NIR photometry of HI galaxies in ZoA (Williams+, 2014)

    NASA Astrophysics Data System (ADS)

    Williams, W. L.; Kraan-Korteweg, R. C.; Woudt, P. A.

    2015-03-01

    The imaging data were acquired with the Japanese InfraRed Survey Facility (IRSF), a 1.4m Alt-Azimuth Cassegrain telescope situated at the South African Astronomical Observatory site in Sutherland, South Africa. The IRSF is equipped with the Simultaneous InfraRed Imager for Unbiased Surveys (SIRIUS) capable of simultaneous imaging in the three NIR bands J, H and Ks. The camera consists of three 1024x1024 pixel HgCdTe (HAWAII) arrays each with a gain of 5.5e-/ADU and a read-out noise of 30e-, cooled to 80K. The field of view is 7.7-arcminx7.7-arcmin and the pixel scale is 0.45arcsec/pix. (2 data files).

  9. VizieR Online Data Catalog: AQ Boo VRI differential light curves (Wang+, 2016)

    NASA Astrophysics Data System (ADS)

    Wang, S.; Zhang, L.; Pi, Q.; Han, X. L.; Zhang, X.; Lu, H.; Wang, D.; Li, T.

    2016-11-01

    On March 22 and April 19 in 2014, we observed AQ Boo with the 60cm telescope at Xinglong Station of the National Astronomical Observatories of China (NAOC). The CCD camera on this telescope has a resolution of 1024 x 1024 pixels and its corresponding field of view is 17'x17' (Yang, 2013NewA...25..109Y). The other three days of data were obtained using the 1-m telescope at Yunnan Observatory of Chinese Academy of Sciences, on January 20, 21 and February 28 in 2015. The CCD camera on this telescope has a resolution of 2048x2048 pixels and its corresponding field of view is 7.3'x7.3'. Bessel VRI filters were used. The exposure times are 100-170s, 50-100s and 50-80s in the V, R, I bands, respectively. (1 data file).

  10. The commercial use of satellite data to monitor the potato crop in the Columbia Basin

    NASA Technical Reports Server (NTRS)

    Waddington, George R., Jr.; Lamb, Frank G.

    1990-01-01

    The imaging of potato crops with satellites is described and evaluated in terms of the commercial application of the remotely sensed data. The identification and analysis of the crops is accomplished with multiple images acquired from the Landsat MSS and TM systems. The data are processed on a PC with image-procesing software which produces images of the seven 1024 x 1024 pixel windows which are subdivided into 21 512 x 512 pixel windows. Maximization of imaged data throughout the year aids in the identification of crop types by IR reflectance. The classification techniques involve the use of six or seven spectral classes for particular image dates. Comparisons with ground-truth data show good agreement; for example, potato fields are identified correctly 90 percent of the time. Acreage estimates and crop-condition assessments can be made from satellite data and used for corrective agricultural action.

  11. The commercial use of satellite data to monitor the potato crop in the Columbia Basin

    NASA Technical Reports Server (NTRS)

    Waddington, George R., Jr.; Lamb, Frank G.

    1990-01-01

    The imaging of potato crops with satellites is described and evaluated in terms of the commercial application of the remotely sensed data. The identification and analysis of the crops is accomplished with multiple images acquired from the Landsat MSS and TM systems. The data are processed on a PC with image-procesing software which produces images of the seven 1024 x 1024 pixel windows which are subdivided into 21 512 x 512 pixel windows. Maximization of imaged data throughout the year aids in the identification of crop types by IR reflectance. The classification techniques involve the use of six or seven spectral classes for particular image dates. Comparisons with ground-truth data show good agreement; for example, potato fields are identified correctly 90 percent of the time. Acreage estimates and crop-condition assessments can be made from satellite data and used for corrective agricultural action.

  12. Dual color IR detection modules, trends and applications

    NASA Astrophysics Data System (ADS)

    Münzberg, M.; Breiter, R.; Cabanski, W.; Hofmann, K.; Lutz, H.; Wendler, J.; Ziegler, J.; Rehm, R.; Walther, M.

    2007-04-01

    The 3rd generation of infrared (IR) detection modules is expected to provide advanced features like higher resolution 1024x1024 or 1280x720 pixels and/or new functions like multicolor or multi band capability, higher frame rates and better thermal resolution. This paper is intended to present the current status and trends at AIM on antimonide type II superlattices (SL) dual color detection module developments for ground and airborne applications in the high performance range, where rapidly changing scenes - like e.g. in case of missile warning applications for airborne platforms or ground based sniper detection systems - require temporal signal coincidence with integration times of typically 1ms. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The type II SL technology provides - similar to QWIP's - an accurate engineering of sensitive layers by MBE with very good homogeneity and yield. IAF and AIM managed already to realize a dual color 384x288 IR module based on this technology. It combines spectral selective detection in the 3 - 4μm wavelength range and 4 - 5 μm wavelength range in each pixel with coincident integration in a 384x288x2 format and 40x40 μm2 pitch. Excellent thermal resolution with NETD < 12 mK @ F/2, 2.8 ms for the longer wavelength range (red band) and NETD < 22 mK @ F/2, 2.8 ms for the shorter wavelength range (blue band) were reported. In the meantime a square design of 256x256x2 pixel with a reduced pitch of 30x30 μm2 is in preparation. In this case with 2 Indium bumps per pixel and a third common contact for all pixels required for temporal coincidence is connected at the outer area of the array. The fill factor is approx. 65% for both wavelength ranges. The reduced size of the array enables the use of a smaller dewar with reduced cooling power and significantly reduced weight and broadens the scope of applications where weight and costs is essential. Design aspects and expected performances

  13. Effect of Pixel's Spatial Characteristics on Recognition of Isolated Pixelized Chinese Character.

    PubMed

    Yang, Kun; Liu, Shuang; Wang, Hong; Liu, Wei; Wu, Yaowei

    2015-01-01

    The influence of pixel's spatial characteristics on recognition of isolated Chinese character was investigated using simulated prosthestic vision. The accuracy of Chinese character recognition with 4 kinds of pixel number (6*6, 8*8, 10*10, and 12*12 pixel array) and 3 kinds of pixel shape (Square, Dot and Gaussian) and different pixel spacing were tested through head-mounted display (HMD). A captured image of Chinese characters in font style of Hei were pixelized with Square, Dot and Gaussian pixel. Results showed that pixel number was the most important factor which could affect the recognition of isolated pixelized Chinese Chartars and the accuracy of recognition increased with the addition of pixel number. 10*10 pixel array could provide enough information for people to recognize an isolated Chinese character. At low resolution (6*6 and 8*8 pixel array), there were little difference of recognition accuracy between different pixel shape and different pixel spacing. While as for high resolution (10*10 and 12*12 pixel array), the fluctuation of pixel shape and pixel spacing could not affect the performance of recognition of isolated pixelized Chinese Character.

  14. Single-pixel hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Suo, Jinli; Wang, Yuwang; Bian, Liheng; Dai, Qionghai

    2016-10-01

    Conventional multispectral imaging methods detect photons of a 3D hyperspectral data cube separately either in the spatial or spectral dimension using array detectors, and are thus photon inefficient and spectrum range limited. Besides, they are usually bulky and highly expensive. To address these issues, this paper presents single-pixel multispectral imaging techniques, which are of high sensitivity, wide spectrum range, low cost and light weight. Two mechanisms are proposed, and experimental validation are also reported.

  15. SAR Image Complex Pixel Representations

    SciTech Connect

    Doerry, Armin W.

    2015-03-01

    Complex pixel values for Synthetic Aperture Radar (SAR) images of uniform distributed clutter can be represented as either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values. Generally, these component values are integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.

  16. CMOS digital pixel sensors: technology and applications

    NASA Astrophysics Data System (ADS)

    Skorka, Orit; Joseph, Dileepan

    2014-04-01

    CMOS active pixel sensor technology, which is widely used these days for digital imaging, is based on analog pixels. Transition to digital pixel sensors can boost signal-to-noise ratios and enhance image quality, but can increase pixel area to dimensions that are impractical for the high-volume market of consumer electronic devices. There are two main approaches to digital pixel design. The first uses digitization methods that largely rely on photodetector properties and so are unique to imaging. The second is based on adaptation of a classical analog-to-digital converter (ADC) for in-pixel data conversion. Imaging systems for medical, industrial, and security applications are emerging lower-volume markets that can benefit from these in-pixel ADCs. With these applications, larger pixels are typically acceptable, and imaging may be done in invisible spectral bands.

  17. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh (Inventor); Cole, David (Inventor); Smith, Roger M (Inventor); Hancock, Bruce R. (Inventor)

    2013-01-01

    The effects of inter pixel capacitance in a pixilated array may be measured by first resetting all pixels in the array to a first voltage, where a first image is read out, followed by resetting only a subset of pixels in the array to a second voltage, where a second image is read out, where the difference in the first and second images provide information about the inter pixel capacitance. Other embodiments are described and claimed.

  18. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh (Inventor); Cole, David (Inventor); Smith, Roger M. (Inventor); Hancock, Bruce R. (Inventor)

    2017-01-01

    The effects of inter pixel capacitance in a pixilated array may be measured by first resetting all pixels in the array to a first voltage, where a first image is read out, followed by resetting only a subset of pixels in the array to a second voltage, where a second image is read out, where the difference in the first and second images provide information about the inter pixel capacitance. Other embodiments are described and claimed.

  19. Sensitivity of landscape metrics to pixel size

    Treesearch

    J. D. Wickham; K. H. Riitters

    1995-01-01

    Analysis of diversity and evenness metrics using land cover data are becoming formalized in landscape ecology. Diversity and evenness metrics are dependent on the pixel size (scale) over which the data are collected. Aerial photography was interpreted for land cover and converted into four raster data sets with 4, 12, 28, and 80 m pixel sizes, representing pixel sizes...

  20. Making a trillion pixels dance

    NASA Astrophysics Data System (ADS)

    Singh, Vivek; Hu, Bin; Toh, Kenny; Bollepalli, Srinivas; Wagner, Stephan; Borodovsky, Yan

    2008-03-01

    In June 2007, Intel announced a new pixelated mask technology. This technology was created to address the problem caused by the growing gap between the lithography wavelength and the feature sizes patterned with it. As this gap has increased, the quality of the image has deteriorated. About a decade ago, Optical Proximity Correction (OPC) was introduced to bridge this gap, but as this gap continued to increase, one could not rely on the same basic set of techniques to maintain image quality. The computational lithography group at Intel sought to alleviate this problem by experimenting with additional degrees of freedom within the mask. This paper describes the resulting pixelated mask technology, and some of the computational methods used to create it. The first key element of this technology is a thick mask model. We realized very early in the development that, unlike traditional OPC methods, the pixelated mask would require a very accurate thick mask model. Whereas in the traditional methods, one can use the relatively coarse approximations such as the boundary layer method, use of such techniques resulted not just in incorrect sizing of parts of the pattern, but in whole features missing. We built on top of previously published domain decomposition methods, and incorporated limitations of the mask manufacturing process, to create an accurate thick mask model. Several additional computational techniques were invoked to substantially increase the speed of this method to a point that it was feasible for full chip tapeout. A second key element of the computational scheme was the comprehension of mask manufacturability, including the vital issue of the number of colors in the mask. While it is obvious that use of three or more colors will give the best image, one has to be practical about projecting mask manufacturing capabilities for such a complex mask. To circumvent this serious issue, we eventually settled on a two color mask - comprising plain glass and etched

  1. Concrete Slump Classification using GLCM Feature Extraction

    NASA Astrophysics Data System (ADS)

    Andayani, Relly; Madenda, Syarifudin

    2016-05-01

    Digital image processing technologies have been widely applies in analyzing concrete structure because the accuracy and real time result. The aim of this study is to classify concrete slump by using image processing technique. For this purpose, concrete mix design of 30 MPa compression strength designed with slump of 0-10 mm, 10-30 mm, 30-60 mm, and 60-180 mm were analysed. Image acquired by Nikon Camera D-7000 using high resolution was set up. In the first step RGB converted to greyimage than cropped to 1024 x 1024 pixel. With open-source program, cropped images to be analysed to extract GLCM feature. The result shows for the higher slump contrast getting lower, but higher correlation, energy, and homogeneity.

  2. Operation of the University of Hawaii 2.2M telescope on Mauna Kea

    NASA Technical Reports Server (NTRS)

    Hall, Donald N. B.

    1991-01-01

    NASA's planetary astronomy program provides part of the funding for the 2.2 meter telescope. The parameters for time on the telescope are laid out. A major instrumental highlight has been the commissioning of a 256 x 256 near infrared camera which uses a Rockwell NICMOS-3 array. At the f/10 focus, image scales of 0.37 and 0.75 arcsec/pixel are available. A new, high quantum efficiency Tektronix 1024 x 1024 CCD saw first light on the telescope in 1991, and was available regularly from April 1991. Data from both of these detectors are transmitted directly to the Sun workstation for immediate analysis by the observers. The autoguider software was enhanced to permit guided tracking on objects have nonsideral motions (i.e., solar system objects).

  3. Digital radiography of the chest by self-scanning linear diode arrays.

    PubMed

    Slasky, B S; Sashin, D; Horton, J A; Sternglass, E J; Bron, K M; Deutsch, M; Herron, J M; Kennedy, W H; Boyer, J W; Girdany, B R

    1987-01-01

    Diode array digital radiography DADR is a method of radiographic imaging that combines the advantages of computer technology with self-scanning linear diode arrays. These digital images are superior to those obtained by film in recording and displaying information in the lightest and the darkest areas of the film, resulting in a balanced image of the entire thorax without compromising detail, and at reduced radiation dose. This is a direct result of the wide dynamic range, high contrast sensitivity, fiber optic coupling, small diode size, short exposure time, and rejection of scattered x-rays of the system coupled with digital post-processing enhancement of the image displayed at 1024 X 1024 pixels.

  4. MWIR and LWIR Megapixel QWIP Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, S. V.; Liu, J. K.; Rafol, S. B.; Thang, J.; Mumolo, Jason; Tidrow, M.; LeVan, P. D.; Hill, C.

    2004-01-01

    A mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024x1024 pixel quantum well infrared photodetector (QWIP) focal plane array has been demonstrated with excellent imagery. MWIR focal plane has given noise equivalent differential temperature (NETD) of 19 mK at 95K operating temperature with f/2.5 optics at 300K background and LWIR focal plane has given NEDT of 13 mK at 70K operating temperature with same optical and background conditions as MWIR array. Both of these focal plane arrays have shown background limited performance (BLIP) at 90K and 70K operating temperatures with the same optics and background conditions. In this paper, we will discuss their performance in quantum efficiency, NETD, uniformity, and operability.

  5. Area x-ray detector based on a lens-coupled charge-coupled device

    SciTech Connect

    Tate, Mark W.; Chamberlain, Darol; Gruner, Sol M.

    2005-08-15

    An area x-ray detector constructed using commercially available 'off-the-shelf' parts is described and its performance is characterized. The detector consists of a 1024x1024 pixel charge-coupled device (CCD) camera optically coupled to x-ray sensitive phosphor screen using a standard 35 mm camera lens. The conversion efficiency, spatial nonuniformity, spatial resolution and the detective quantum efficiency of the detector have been measured. Also shown is an example of data taken with the detector. The detector is a relatively low-cost device suitable for a wide variety of quantitative x-ray experiments where the input area need not be larger than about 70 mm across.

  6. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2004-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  7. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    1995-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  8. Proceedings of PIXEL98 -- International pixel detector workshop

    SciTech Connect

    Anderson, D.F.; Kwan, S.

    1998-08-01

    Experiments around the globe face new challenges of more precision in the face of higher interaction rates, greater track densities, and higher radiation doses, as they look for rarer and rarer processes, leading many to incorporate pixelated solid-state detectors into their plans. The highest-readout rate devices require new technologies for implementation. This workshop reviewed recent, significant progress in meeting these technical challenges. Participants presented many new results; many of them from the weeks--even days--just before the workshop. Brand new at this workshop were results on cryogenic operation of radiation-damaged silicon detectors (dubbed the Lazarus effect). Other new work included a diamond sensor with 280-micron collection distance; new results on breakdown in p-type silicon detectors; testing of the latest versions of read-out chip and interconnection designs; and the radiation hardness of deep-submicron processes.

  9. Active pixel sensor with intra-pixel charge transfer

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra (Inventor); Kemeny, Sabrina E. (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

  10. Infrared astronomy - Pixels to spare

    SciTech Connect

    Mccaughrean, M. )

    1991-07-01

    An infrared CCD camera containing an array with 311,040 pixels arranged in 486 rows of 640 each is tested. The array is a chip of platinum silicide (PtSi), sensitive to photons with wavelengths between 1 and 6 microns. Observations of the Hubble Space Telescope, Mars, Pluto and moon are reported. It is noted that the satellite's twin solar-cell arrays, at an apparent separation of about 1 1/4 arc second, are well resolved. Some two dozen video frames were stacked to make each presented image of Mars at 1.6 microns; at this wavelength Mars appears much as it does in visible light. A stack of 11 images at a wavelength of 1.6 microns is used for an image of Jupiter with its Great Red Spot and moons Io and Europa.

  11. Dead pixel replacement in LWIR microgrid polarimeters.

    PubMed

    Ratliff, Bradley M; Tyo, J Scott; Boger, James K; Black, Wiley T; Bowers, David L; Fetrow, Matthew P

    2007-06-11

    LWIR imaging arrays are often affected by nonresponsive pixels, or "dead pixels." These dead pixels can severely degrade the quality of imagery and often have to be replaced before subsequent image processing and display of the imagery data. For LWIR arrays that are integrated with arrays of micropolarizers, the problem of dead pixels is amplified. Conventional dead pixel replacement (DPR) strategies cannot be employed since neighboring pixels are of different polarizations. In this paper we present two DPR schemes. The first is a modified nearest-neighbor replacement method. The second is a method based on redundancy in the polarization measurements.We find that the redundancy-based DPR scheme provides an order-of-magnitude better performance for typical LWIR polarimetric data.

  12. Equivalence of a Bit Pixel Image to a Quantum Pixel Image

    NASA Astrophysics Data System (ADS)

    Ortega, Laurel Carlos; Dong, Shi-Hai; Cruz-Irisson, M.

    2015-11-01

    We propose a new method to transform a pixel image to the corresponding quantum-pixel using a qubit per pixel to represent each pixels classical weight in a quantum image matrix weight. All qubits are linear superposition, changing the coefficients level by level to the entire longitude of the gray scale with respect to the base states of the qubit. Classically, these states are just bytes represented in a binary matrix, having code combinations of 1 or 0 at all pixel locations. This method introduces a qubit-pixel image representation of images captured by classical optoelectronic methods. Supported partially by the project 20150964-SIP-IPN, Mexico

  13. Method for fabricating pixelated silicon device cells

    SciTech Connect

    Nielson, Gregory N.; Okandan, Murat; Cruz-Campa, Jose Luis; Nelson, Jeffrey S.; Anderson, Benjamin John

    2015-08-18

    A method, apparatus and system for flexible, ultra-thin, and high efficiency pixelated silicon or other semiconductor photovoltaic solar cell array fabrication is disclosed. A structure and method of creation for a pixelated silicon or other semiconductor photovoltaic solar cell array with interconnects is described using a manufacturing method that is simplified compared to previous versions of pixelated silicon photovoltaic cells that require more microfabrication steps.

  14. [Hadamard transform spectrometer mixed pixels' unmixing method].

    PubMed

    Yan, Peng; Hu, Bing-Liang; Liu, Xue-Bin; Sun, Wei; Li, Li-Bo; Feng, Yu-Tao; Liu, Yong-Zheng

    2011-10-01

    Hadamard transform imaging spectrometer is a multi-channel digital transform spectrometer detection technology, this paper based on digital micromirror array device (DMD) of the Hadamard transform spectrometer working principle and instrument structure, obtained by the imaging sensor mixed pixel were analyzed, theory derived the solution of pixel aliasing hybrid method, simulation results show that the method is simple and effective to improve the accuracy of mixed pixel spectrum more than 10% recovery.

  15. Commissioning of the CMS Forward Pixel Detector

    SciTech Connect

    Kumar, Ashish; /SUNY, Buffalo

    2008-12-01

    The Compact Muon Solenoid (CMS) experiment is scheduled for physics data taking in summer 2009 after the commissioning of high energy proton-proton collisions at Large Hadron Collider (LHC). At the core of the CMS all-silicon tracker is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution, 3D tracking points, essential for pattern recognition and precise vertexing, while being embedded in a hostile radiation environment. The end disks of the pixel detector, known as the Forward Pixel detector, has been assembled and tested at Fermilab, USA. It has 18 million pixel cells with dimension 100 x 150 {micro}m{sup 2}. The complete forward pixel detector was shipped to CERN in December 2007, where it underwent extensive system tests for commissioning prior to the installation. The pixel system was put in its final place inside the CMS following the installation and bake out of the LHC beam pipe in July 2008. It has been integrated with other sub-detectors in the readout since September 2008 and participated in the cosmic data taking. This report covers the strategy and results from commissioning of CMS forward pixel detector at CERN.

  16. Implementation of TDI based digital pixel ROIC with 15μm pixel pitch

    NASA Astrophysics Data System (ADS)

    Ceylan, Omer; Shafique, Atia; Burak, A.; Caliskan, Can; Abbasi, Shahbaz; Yazici, Melik; Gurbuz, Yasar

    2016-05-01

    A 15um pixel pitch digital pixel for LWIR time delay integration (TDI) applications is implemented which occupies one fourth of pixel area compared to previous digital TDI implementation. TDI is implemented on 8 pixels with oversampling rate of 2. ROIC provides 16 bits output with 8 bits of MSB and 8 bits of LSB. Pixel can store 75 M electrons with a quantization noise of 500 electrons. Digital pixel TDI implementation is advantageous over analog counterparts considering power consumption, chip area and signal-to-noise ratio. Digital pixel TDI ROIC is fabricated with 0.18um CMOS process. In digital pixel TDI implementation photocurrent is integrated on a capacitor in pixel and converted to digital data in pixel. This digital data triggers the summation counters which implements TDI addition. After all pixels in a row contribute, the summed data is divided to the number of TDI pixels(N) to have the actual output which is square root of N improved version of a single pixel output in terms of signal-to-noise-ratio (SNR).

  17. High stroke pixel for a deformable mirror

    DOEpatents

    Miles, Robin R.; Papavasiliou, Alexandros P.

    2005-09-20

    A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.

  18. SNR improvement for hyperspectral application using frame and pixel binning

    NASA Astrophysics Data System (ADS)

    Rehman, Sami Ur; Kumar, Ankush; Banerjee, Arup

    2016-05-01

    Hyperspectral imaging spectrometer systems are increasingly being used in the field of remote sensing for variety of civilian and military applications. The ability of such instruments in discriminating finer spectral features along with improved spatial and radiometric performance have made such instruments a powerful tool in the field of remote sensing. Design and development of spaceborne hyper spectral imaging spectrometers poses lot of technological challenges in terms of optics, dispersion element, detectors, electronics and mechanical systems. The main factors that define the type of detectors are the spectral region, SNR, dynamic range, pixel size, number of pixels, frame rate, operating temperature etc. Detectors with higher quantum efficiency and higher well depth are the preferred choice for such applications. CCD based Si detectors serves the requirement of high well depth for VNIR band spectrometers but suffers from smear. Smear can be controlled by using CMOS detectors. Si CMOS detectors with large format arrays are available. These detectors generally have smaller pitch and low well depth. Binning technique can be used with available CMOS detectors to meet the large swath, higher resolution and high SNR requirements. Availability of larger dwell time of satellite can be used to bin multiple frames to increase the signal collection even with lesser well depth detectors and ultimately increase the SNR. Lab measurements reveal that SNR improvement by frame binning is more in comparison to pixel binning. Effect of pixel binning as compared to the frame binning will be discussed and degradation of SNR as compared to theoretical value for pixel binning will be analyzed.

  19. Sub-pixel mapping of water boundaries using pixel swapping algorithm (case study: Tagliamento River, Italy)

    NASA Astrophysics Data System (ADS)

    Niroumand-Jadidi, Milad; Vitti, Alfonso

    2015-10-01

    Taking the advantages of remotely sensed data for mapping and monitoring of water boundaries is of particular importance in many different management and conservation activities. Imagery data are classified using automatic techniques to produce maps entering the water bodies' analysis chain in several and different points. Very commonly, medium or coarse spatial resolution imagery is used in studies of large water bodies. Data of this kind is affected by the presence of mixed pixels leading to very outstanding problems, in particular when dealing with boundary pixels. A considerable amount of uncertainty inescapably occurs when conventional hard classifiers (e.g., maximum likelihood) are applied on mixed pixels. In this study, Linear Spectral Mixture Model (LSMM) is used to estimate the proportion of water in boundary pixels. Firstly by applying an unsupervised clustering, the water body is identified approximately and a buffer area considered ensuring the selection of entire boundary pixels. Then LSMM is applied on this buffer region to estimate the fractional maps. However, resultant output of LSMM does not provide a sub-pixel map corresponding to water abundances. To tackle with this problem, Pixel Swapping (PS) algorithm is used to allocate sub-pixels within mixed pixels in such a way to maximize the spatial proximity of sub-pixels and pixels in the neighborhood. The water area of two segments of Tagliamento River (Italy) are mapped in sub-pixel resolution (10m) using a 30m Landsat image. To evaluate the proficiency of the proposed approach for sub-pixel boundary mapping, the image is also classified using a conventional hard classifier. A high resolution image of the same area is also classified and used as a reference for accuracy assessment. According to the results, sub-pixel map shows in average about 8 percent higher overall accuracy than hard classification and fits very well in the boundaries with the reference map.

  20. It's not the pixel count, you fool

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2012-01-01

    The first thing a "marketing guy" asks the digital camera engineer is "how many pixels does it have, for we need as many mega pixels as possible since the other guys are killing us with their "umpteen" mega pixel pocket sized digital cameras. And so it goes until the pixels get smaller and smaller in order to inflate the pixel count in the never-ending pixel-wars. These small pixels just are not very good. The truth of the matter is that the most important feature of digital cameras in the last five years is the automatic motion control to stabilize the image on the sensor along with some very sophisticated image processing. All the rest has been hype and some "cool" design. What is the future for digital imaging and what will drive growth of camera sales (not counting the cell phone cameras which totally dominate the market in terms of camera sales) and more importantly after sales profits? Well sit in on the Dark Side of Color and find out what is being done to increase the after sales profits and don't be surprised if has been done long ago in some basement lab of a photographic company and of course, before its time.

  1. Micro-Pixel Image Position Sensing Testbed

    NASA Technical Reports Server (NTRS)

    Nemati, Bijan; Shao, Michael; Zhai, Chengxing; Erlig, Hernan; Wang, Xu; Goullioud, Renaud

    2011-01-01

    The search for Earth-mass planets in the habitable zones of nearby Sun-like stars is an important goal of astrophysics. This search is not feasible with the current slate of astronomical instruments. We propose a new concept for microarcsecond astrometry which uses a simplified instrument and hence promises to be low cost. The concept employs a telescope with only a primary, laser metrology applied to the focal plane array, and new algorithms for measuring image position and displacement on the focal plane. The required level of accuracy in both the metrology and image position sensing is at a few micro-pixels. We have begun a detailed investigation of the feasibility of our approach using simulations and a micro-pixel image position sensing testbed called MCT. So far we have been able to demonstrate that the pixel-to-pixel distances in a focal plane can be measured with a precision of 20 micro-pixels and image-to-image distances with a precision of 30 micro-pixels. We have also shown using simulations that our image position algorithm can achieve accuracy of 4 micro-pixels in the presence of lambda/20 wavefront errors.

  2. High spatial resolution performance of pixelated scintillators

    NASA Astrophysics Data System (ADS)

    Shigeta, Kazuki; Fujioka, Nobuyasu; Murai, Takahiro; Hikita, Izumi; Morinaga, Tomohiro; Tanino, Takahiro; Kodama, Haruhito; Okamura, Masaki

    2017-03-01

    In indirect conversion flat panel detectors (FPDs) for digital X-ray imaging, scintillating materials such as Terbiumdoped Gadolinium Oxysulfide (Gadox) convert X-ray into visible light, and an amorphous silicon (a-Si) photodiode array converts the light into electrons. It is, however, desired that the detector spatial resolution is improved because the light spreading inside scintillator causes crosstalk to next a-Si photodiode pixels and the resolution is degraded compared with direct conversion FPDs which directly convert X-ray into electrons by scintillating material such as amorphous selenium. In this study, the scintillator was pixelated with same pixel pitch as a-Si photodiode array by barrier rib structure to limit the light spreading, and the detector spatial resolution was improved. The FPD with pixelated scintillator was manufactured as follows. The barrier rib structure with 127μm pitch was fabricated on a substrate by a photosensitive organic-inorganic paste method, and a reflective layer was coated on the surface of the barrier rib, then the structure was filled up with Gadox particles. The pixelated scintillator was aligned with 127μm pixel pitch of a-Si photodiode array and set as a FPD. The FPD with pixelated scintillator showed high modulation transfer function (MTF) and 0.94 at 1cycle/mm and 0.88 at 2cycles/mm were achieved. The MTF values were almost equal to the maximum value that can be theoretically achieved in the FPD with 127μm pixel pitch of a-Si photodiode array. Thus the FPD with pixelated scintillators has great potential to apply for high spatial resolution applications such as mammography and nondestructive testing.

  3. LISe pixel detector for neutron imaging

    NASA Astrophysics Data System (ADS)

    Herrera, Elan; Hamm, Daniel; Wiggins, Brenden; Milburn, Rob; Burger, Arnold; Bilheux, Hassina; Santodonato, Louis; Chvala, Ondrej; Stowe, Ashley; Lukosi, Eric

    2016-10-01

    Semiconducting lithium indium diselenide, 6LiInSe2 or LISe, has promising characteristics for neutron detection applications. The 95% isotopic enrichment of 6Li results in a highly efficient thermal neutron-sensitive material. In this study, we report on a proof-of-principle investigation of a semiconducting LISe pixel detector to demonstrate its potential as an efficient neutron imager. The LISe pixel detector had a 4×4 of pixels with a 550 μm pitch on a 5×5×0.56 mm3 LISe substrate. An experimentally verified spatial resolution of 300 μm was observed utilizing a super-sampling technique.

  4. Per-Pixel Lighting Data Analysis

    SciTech Connect

    Inanici, Mehlika

    2005-08-01

    This report presents a framework for per-pixel analysis of the qualitative and quantitative aspects of luminous environments. Recognizing the need for better lighting analysis capabilities and appreciating the new measurement abilities developed within the LBNL Lighting Measurement and Simulation Toolbox, ''Per-pixel Lighting Data Analysis'' project demonstrates several techniques for analyzing luminance distribution patterns, luminance ratios, adaptation luminance and glare assessment. The techniques are the syntheses of the current practices in lighting design and the unique practices that can be done with per-pixel data availability. Demonstrated analysis techniques are applicable to both computer-generated and digitally captured images (physically-based renderings and High Dynamic Range photographs).

  5. Anode readout for pixellated CZT detectors

    NASA Astrophysics Data System (ADS)

    Narita, Tomohiko; Grindlay, Jonathan E.; Hong, Jaesub; Niestemski, Francis C.

    2004-02-01

    Determination of the photon interaction depth offers numerous advantages for an astronomical hard X-ray telescope. The interaction depth is typically derived from two signals: anode and cathode, or collecting and non-collecting electrodes. We present some preliminary results from our depth sensing detectors using only the anode pixel signals. By examining several anode pixel signals simultaneously, we find that we can estimate the interaction depth, and get sub-pixel 2-D position resolution. We discuss our findings and the requirements for future ASIC development.

  6. Color constancy at a pixel.

    PubMed

    Finlayson, G D; Hordley, S D

    2001-02-01

    In computational terms we can solve the color constancy problem if device red, green, and blue sensor responses, or RGB's, for surfaces seen under an unknown illuminant can be mapped to corresponding RGB's under a known reference light. In recent years almost all authors have argued that this three-dimensional problem is too hard. It is argued that because a bright light striking a dark surface results in the same physical spectra as those of a dim light incident on a light surface, the magnitude of RGB's cannot be recovered. Consequently, modern color constancy algorithms attempt only to recover image chromaticities under the reference light: They solve a two-dimensional problem. While significant progress has been made toward achieving chromaticity constancy, recent work has shown that the most advanced algorithms are unable to render chromaticity stable enough so that it can be used as a cue for object recognition [B. V. Funt, K. Bernard, and L. Martin, in Proceedings of the Fifth European Conference on Computer Vision (European Vision Society, Springer-Verlag, Berlin, 1998), Vol. II, p. 445.] We take this reductionist approach a little further and look at the one-dimensional color constancy problem. We ask, Is there a single color coordinate, a function of image chromaticities, for which the color constancy problem can be solved? Our answer is an emphatic yes. We show that there exists a single invariant color coordinate, a function of R, G, and B, that depends only on surface reflectance. Two corollaries follow. First, given an RGB image of a scene viewed under any illuminant, we can trivially synthesize the same gray-scale image (we simply code the invariant coordinate as a gray scale). Second, this result implies that we can solve the one-dimensional color constancy problem at a pixel (in scenes with no color diversity whatsoever). We present experiments that show that invariant gray-scale histograms are a stable feature for object recognition. Indexing on

  7. Pixel-by-pixel VIS/NIR and LIR sensor fusion system

    NASA Astrophysics Data System (ADS)

    Zhang, Evan; Zhang, James S.; Song, Vivian W.; Chin, Ken P.; Hu, Gelbert

    2003-01-01

    Visible (VIS) camera (such as CCD) or Near Infrared (NIR) camera (such as low light level CCD or image intensifier) has high resolution and is easy to distinguish enemy and foe, but it cannot see through thin fog/cloud, heavy smoke/dust, foliage, camouflage, and darkness. The Long Infrared (LIR) imager can overcome above problems, but the resolution is too low and it cannot see the NIR aiming light from enemy. The best solution is to fuse the VIS/NIR and LIR sensors to overcome their shortcomings and take advantages of both sensors. In order to see the same target without parallax, the fusio system must have a common optical aperature. In this paper, three common optical apertures are designed: common reflective objective lens, common beam splitter, and common transmissive objective lens. The first one has very small field of view and the second one needs two heads, so the best choice is the third one, but we must find suitable optical materials and correct the color aberrations from 0.6 to 12 μ. It is a tough job. By choosing ZnSe as the first common piece of the objective lens and using glass for NIR and Ge (or IR glass) for LIR as rest pieces, we only need to and are able to correct the aberrations from 0.6 to 1.0 μ for NIR and from 8 to 12 μ for LIR. Finally, a common reflective objective lens and the common beam splitter are also successfully designed. Five application examples are given. In the digital signal processing, we use only one Altera chip. After inserting data, scaling the image size, and adjusting the signal level, the LIR will have the same format and same pixel number of the VIS/NIR, so real-time pixel-by-pixel sensor fusion is realized. The digital output can be used for further image processing and automatic target recognition, such as if we overlap the LIR image on the VIS/NIR image for missile guidance or rifle sight we don't need to worry about the time and the environment again. A gum-size wireless transmitter is also designed that is

  8. Operation and Performance of the Mars Exploration Rover Imaging System on the Martian Surface

    NASA Technical Reports Server (NTRS)

    Maki, Justin N.; Litwin, Todd; Herkenhoff, Ken

    2005-01-01

    This slide presentation details the Mars Exploration Rover (MER) imaging system. Over 144,000 images have been gathered from all Mars Missions, with 83.5% of them being gathered by MER. Each Rover has 9 cameras (Navcam, front and rear Hazcam, Pancam, Microscopic Image, Descent Camera, Engineering Camera, Science Camera) and produces 1024 x 1024 (1 Megapixel) images in the same format. All onboard image processing code is implemented in flight software and includes extensive processing capabilities such as autoexposure, flat field correction, image orientation, thumbnail generation, subframing, and image compression. Ground image processing is done at the Jet Propulsion Laboratory's Multimission Image Processing Laboratory using Video Image Communication and Retrieval (VICAR) while stereo processing (left/right pairs) is provided for raw image, radiometric correction; solar energy maps,triangulation (Cartesian 3-spaces) and slope maps.

  9. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2014-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  10. Pixels, Imagers and Related Fabrication Methods

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

    2016-01-01

    Pixels, imagers and related fabrication methods are described. The described methods result in cross-talk reduction in imagers and related devices by generating depletion regions. The devices can also be used with electronic circuits for imaging applications.

  11. Readout and DAQ for Pixel Detectors

    NASA Astrophysics Data System (ADS)

    Platkevic, Michal

    2010-01-01

    Data readout and acquisition control of pixel detectors demand the transfer of significantly a large amounts of bits between the detector and the computer. For this purpose dedicated interfaces are used which are designed with focus on features like speed, small dimensions or flexibility of use such as digital signal processors, field-programmable gate arrays (FPGA) and USB communication ports. This work summarizes the readout and DAQ system built for state-of-the-art pixel detectors of the Medipix family.

  12. Design of the small pixel pitch ROIC

    NASA Astrophysics Data System (ADS)

    Liang, Qinghua; Jiang, Dazhao; Chen, Honglei; Zhai, Yongcheng; Gao, Lei; Ding, Ruijun

    2014-11-01

    Since the technology trend of the third generation IRFPA towards resolution enhancing has steadily progressed,the pixel pitch of IRFPA has been greatly reduced.A 640×512 readout integrated circuit(ROIC) of IRFPA with 15μm pixel pitch is presented in this paper.The 15μm pixel pitch ROIC design will face many challenges.As we all known,the integrating capacitor is a key performance parameter when considering pixel area,charge capacity and dynamic range,so we adopt the effective method of 2 by 2 pixels sharing an integrating capacitor to solve this problem.The input unit cell architecture will contain two paralleled sample and hold parts,which not only allow the FPA to be operated in full frame snapshot mode but also save relatively unit circuit area.Different applications need more matching input unit circuits. Because the dimension of 2×2 pixels is 30μm×30μm, an input stage based on direct injection (DI) which has medium injection ratio and small layout area is proved to be suitable for middle wave (MW) while BDI with three-transistor cascode amplifier for long wave(LW). By adopting the 0.35μm 2P4M mixed signal process, the circuit architecture can make the effective charge capacity of 7.8Me- per pixel with 2.2V output range for MW and 7.3 Me- per pixel with 2.6V output range for LW. According to the simulation results, this circuit works well under 5V power supply and achieves less than 0.1% nonlinearity.

  13. Toward Multispectral Imaging with Colloidal Metasurface Pixels.

    PubMed

    Stewart, Jon W; Akselrod, Gleb M; Smith, David R; Mikkelsen, Maiken H

    2017-02-01

    Multispectral colloidal metasurfaces are fabricated that exhibit greater than 85% absorption and ≈100 nm linewidths by patterning film-coupled nanocubes in pixels using a fusion of bottom-up and top-down fabrication techniques over wafer-scale areas. With this technique, the authors realize a multispectral pixel array consisting of six resonances between 580 and 1125 nm and reconstruct an RGB image with 9261 color combinations.

  14. Holographic imaging with single pixel sensor

    NASA Astrophysics Data System (ADS)

    Leportier, Thibault; Lee, Young Tack; Hwang, Do Kyung; Park, Min-Chul

    2016-09-01

    Imaging techniques based on CCD sensors presenting very high number of pixels enable to record images with high resolution. However, the huge storage load and high bandwidth required to store and transmit digital holographic information are technical bottlenecks that should be overcome for the future of holographic display. Techniques to capture images with single pixel sensors have been greatly improved recently with the development of compressive sensing algorithm (CS). Since interference patterns may be considered sparse, the number of measurements required to recover the information with CS is lower than the number of pixels of the reconstructed image. In addition, this method does not need any scanning system. One other advantage of single pixel imaging is that the cost of recording system can be dramatically reduced since high-resolution cameras are expensive while compressive sensing exploits only one pixel. In this paper, we present an imaging system based on phase-shifting holography. First, simulations were performed to confirm that hologram could be reconstructed by compressive sensing even if the number of measurements was smaller than the number of pixels. Then, experimental set-up was realized. Several holograms with different phase shifts introduced by quarter and half wave plates in the reference beam were acquired. We demonstrated that our system enables the reconstruction of the object.

  15. Steganography based on pixel intensity value decomposition

    NASA Astrophysics Data System (ADS)

    Abdulla, Alan Anwar; Sellahewa, Harin; Jassim, Sabah A.

    2014-05-01

    This paper focuses on steganography based on pixel intensity value decomposition. A number of existing schemes such as binary, Fibonacci, Prime, Natural, Lucas, and Catalan-Fibonacci (CF) are evaluated in terms of payload capacity and stego quality. A new technique based on a specific representation is proposed to decompose pixel intensity values into 16 (virtual) bit-planes suitable for embedding purposes. The proposed decomposition has a desirable property whereby the sum of all bit-planes does not exceed the maximum pixel intensity value, i.e. 255. Experimental results demonstrate that the proposed technique offers an effective compromise between payload capacity and stego quality of existing embedding techniques based on pixel intensity value decomposition. Its capacity is equal to that of binary and Lucas, while it offers a higher capacity than Fibonacci, Prime, Natural, and CF when the secret bits are embedded in 1st Least Significant Bit (LSB). When the secret bits are embedded in higher bit-planes, i.e., 2nd LSB to 8th Most Significant Bit (MSB), the proposed scheme has more capacity than Natural numbers based embedding. However, from the 6th bit-plane onwards, the proposed scheme offers better stego quality. In general, the proposed decomposition scheme has less effect in terms of quality on pixel value when compared to most existing pixel intensity value decomposition techniques when embedding messages in higher bit-planes.

  16. Small pixel oversampled IR focal plane arrays

    NASA Astrophysics Data System (ADS)

    Caulfield, John; Curzan, Jon; Lewis, Jay; Dhar, Nibir

    2015-06-01

    We report on a new high definition high charge capacity 2.1 Mpixel MWIR Infrared Focal Plane Array. This high definition (HD) FPA utilizes a small 5 um pitch pixel size which is below the Nyquist limit imposed by the optical systems Point Spread Function (PSF). These smaller sub diffraction limited pixels allow spatial oversampling of the image. We show that oversampling IRFPAs enables improved fidelity in imaging including resolution improvements, advanced pixel correlation processing to reduce false alarm rates, improved detection ranges, and an improved ability to track closely spaced objects. Small pixel HD arrays are viewed as the key component enabling lower size, power and weight of the IR Sensor System. Small pixels enables a reduction in the size of the systems components from the smaller detector and ROIC array, the reduced optics focal length and overall lens size, resulting in an overall compactness in the sensor package, cooling and associated electronics. The highly sensitive MWIR small pixel HD FPA has the capability to detect dimmer signals at longer ranges than previously demonstrated.

  17. Simulation study of pixel detector charge digitization

    NASA Astrophysics Data System (ADS)

    Wang, Fuyue; Nachman, Benjamin; Sciveres, Maurice; Lawrence Berkeley National Laboratory Team

    2017-01-01

    Reconstruction of tracks from nearly overlapping particles, called Tracking in Dense Environments (TIDE), is an increasingly important component of many physics analyses at the Large Hadron Collider as signatures involving highly boosted jets are investigated. TIDE makes use of the charge distribution inside a pixel cluster to resolve tracks that share one of more of their pixel detector hits. In practice, the pixel charge is discretized using the Time-over-Threshold (ToT) technique. More charge information is better for discrimination, but more challenging for designing and operating the detector. A model of the silicon pixels has been developed in order to study the impact of the precision of the digitized charge distribution on distinguishing multi-particle clusters. The output of the GEANT4-based simulation is used to train neutral networks that predict the multiplicity and location of particles depositing energy inside one cluster of pixels. By studying the multi-particle cluster identification efficiency and position resolution, we quantify the trade-off between the number of ToT bits and low-level tracking inputs. As both ATLAS and CMS are designing upgraded detectors, this work provides guidance for the pixel module designs to meet TIDE needs. Work funded by the China Scholarship Council and the Office of High Energy Physics of the U.S. Department of Energy under contract DE-AC02-05CH11231.

  18. Design of a 12-megapixel imager with a nanowatt A/D converter at each pixel

    NASA Astrophysics Data System (ADS)

    Mandl, William J.

    2003-09-01

    The design for a large format digital visible light area array was developed based on A/D conversion at each pixel. Production CMOS technology was used in the development of a monolithic front side illuminated photo diode pixel. Each pixel includes a one loop MOSAD, multiplexed oversample A/D, converter, the photo diode and a buffered output to support a very large array format operating at a high frame rate. MOSAD is a modification of the delta sigma approach to A/D conversion. The requirements are to develop a 4,000 x 3,000 pixel array capable of up to 1,000 frames per second sample rate. A design was developed using the AMIS 0.35 μm CMOS process with a single poly and three metal layers. To approximately fit a 35 millimeter optics format, a pixel size of 8.5 μm was selected. There are no operational amplifiers required at the pixel to perform the A/D function, thus allowing a high fill factor. With this pixel size, a 48% fill factor and 38% photo diode area was achieved. The design can produce a pixel size of 4.3 μm square with the use of 0.18 μm CMOS without sacrificing fill factor. Alternate approaches to satisfy the 1 kiloframe sample rate with up to 10 bits dynamic range were analyzed. The design is still in progress with layout and simulation of the critical elements complete. This development program is sponsored by the Army White Sands Missile Range.

  19. Focal plane array with modular pixel array components for scalability

    SciTech Connect

    Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

    2014-12-09

    A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

  20. Spatial clustering of pixels of a multispectral image

    DOEpatents

    Conger, James Lynn

    2014-08-19

    A method and system for clustering the pixels of a multispectral image is provided. A clustering system computes a maximum spectral similarity score for each pixel that indicates the similarity between that pixel and the most similar neighboring. To determine the maximum similarity score for a pixel, the clustering system generates a similarity score between that pixel and each of its neighboring pixels and then selects the similarity score that represents the highest similarity as the maximum similarity score. The clustering system may apply a filtering criterion based on the maximum similarity score so that pixels with similarity scores below a minimum threshold are not clustered. The clustering system changes the current pixel values of the pixels in a cluster based on an averaging of the original pixel values of the pixels in the cluster.

  1. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    SciTech Connect

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T.; Gruner, Sol M.

    2016-01-28

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. Lastly, we detail the characteristics, operation, testing and application of the detector.

  2. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    DOE PAGES

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; ...

    2016-01-28

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses atmore » megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. Lastly, we detail the characteristics, operation, testing and application of the detector.« less

  3. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation.

    PubMed

    Philipp, Hugh T; Tate, Mark W; Purohit, Prafull; Shanks, Katherine S; Weiss, Joel T; Gruner, Sol M

    2016-03-01

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8-12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10-100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. The characteristics, operation, testing and application of the detector are detailed.

  4. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    PubMed Central

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T.; Gruner, Sol M.

    2016-01-01

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. The characteristics, operation, testing and application of the detector are detailed. PMID:26917125

  5. Evolution of Fractal Parameters through Development Stage of Soil Crust

    NASA Astrophysics Data System (ADS)

    Ospina, Abelardo; Florentino, Adriana; Tarquis, Ana Maria

    2016-04-01

    Soil surface characteristics are subjected to changes driven by several interactions between water, air, biotic and abiotic components. One of the examples of such interactions is provided through biological soil crusts (BSC) in arid and semi-arid environments. BSC are communities composed of cyanobacteria, fungi, mosses, lichens, algae and liverworts covering the soil surface and play an important role in ecosystem functioning. The characteristics and formation of these BSC influence the soil hydrological balance, control the mass of eroded sediment, increase stability of soil surface, and influence plant productivity through the modification of nitrogen and carbon cycle. The site of this work is located at Quibor and Ojo de Agua (Lara state, Venezuela). The Quibor Depression in Venezuela is a major agricultural area being at semi-arid conditions and limited drainage favor the natural process of salinization. Additionally, the extension and intensification of agriculture has led to over-exploitation of groundwater in the past 30 years (Méndoza et al., 2013). The soil microbial crust develops initially on physical crusts which are mainly generated since wetting and drying, being a recurrent feature in the Quíbor arid zone. The microbiotic crust is organic, composed of macro organisms (bryophytes and lichens) and microorganisms (cyanobacteria, fungi algae, etc.); growing on the ground, forming a thickness no greater than 3 mm. For further details see Toledo and Florentino (2009). This study focus on characterize the development stage of the BSC based on image analysis. To this end, grayscale images of different types of biological soil crust at different stages where taken, each image corresponding to an area of 12.96 cm2 with a resolution of 1024x1024 pixels (Ospina et al., 2015). For each image lacunarity and fractal dimension through the differential box counting method were calculated. These were made with the software ImageJ/Fraclac (Karperien, 2013

  6. HUBBLE SPACE TELESCOPE PIXEL ANALYSIS OF THE INTERACTING S0 GALAXY NGC 5195 (M51B)

    SciTech Connect

    Lee, Joon Hyeop; Kim, Sang Chul; Ree, Chang Hee; Kim, Minjin; Jeong, Hyunjin; Lee, Jong Chul; Kyeong, Jaemann E-mail: sckim@kasi.re.kr E-mail: mkim@kasi.re.kr E-mail: jclee@kasi.re.kr

    2012-08-01

    We report the properties of the interacting S0 galaxy NGC 5195 (M51B), revealed in a pixel analysis using the Hubble Space Telescope/Advanced Camera for Surveys images in the F435W, F555W, and F814W (BVI) bands. We analyze the pixel color-magnitude diagram (pCMD) of NGC 5195, focusing on the properties of its red and blue pixel sequences and the difference from the pCMD of NGC 5194 (M51A; the spiral galaxy interacting with NGC 5195). The red pixel sequence of NGC 5195 is redder than that of NGC 5194, which corresponds to the difference in the dust optical depth of 2 < {Delta}{tau}{sub V} < 4 at fixed age and metallicity. The blue pixel sequence of NGC 5195 is very weak and spatially corresponds to the tidal bridge between the two interacting galaxies. This implies that the blue pixel sequence is not an ordinary feature in the pCMD of an early-type galaxy, but that it is a transient feature of star formation caused by the galaxy-galaxy interaction. We also find a difference in the shapes of the red pixel sequences on the pixel color-color diagrams (pCCDs) of NGC 5194 and NGC 5195. We investigate the spatial distributions of the pCCD-based pixel stellar populations. The young population fraction in the tidal bridge area is larger than that in other areas by a factor >15. Along the tidal bridge, young populations seem to be clumped particularly at the middle point of the bridge. On the other hand, the dusty population shows a relatively wide distribution between the tidal bridge and the center of NGC 5195.

  7. Mapping Electrical Crosstalk in Pixelated Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Seshadri, S.; Cole, D. M.; Hancock, B. R.; Smith, R. M.

    2008-01-01

    Electronic coupling effects such as Inter-Pixel Capacitance (IPC) affect the quantitative interpretation of image data from CMOS, hybrid visible and infrared imagers alike. Existing methods of characterizing IPC do not provide a map of the spatial variation of IPC over all pixels. We demonstrate a deterministic method that provides a direct quantitative map of the crosstalk across an imager. The approach requires only the ability to reset single pixels to an arbitrary voltage, different from the rest of the imager. No illumination source is required. Mapping IPC independently for each pixel is also made practical by the greater S/N ratio achievable for an electrical stimulus than for an optical stimulus, which is subject to both Poisson statistics and diffusion effects of photo-generated charge. The data we present illustrates a more complex picture of IPC in Teledyne HgCdTe and HyViSi focal plane arrays than is presently understood, including the presence of a newly discovered, long range IPC in the HyViSi FPA that extends tens of pixels in distance, likely stemming from extended field effects in the fully depleted substrate. The sensitivity of the measurement approach has been shown to be good enough to distinguish spatial structure in IPC of the order of 0.1%.

  8. Photothermal Multi-Pixel Imaging Microscope

    SciTech Connect

    Stolz, C J; Chinn, D J; Huber, R D; Weinzapfel, C L; Wu, Z

    2003-12-01

    Photothermal microscopy is a useful nondestructive tool for the identification of fluence-limiting defects in optical coatings. Traditional photothermal microscopes are single-pixel detection devices. Samples are scanned under the microscope to generate a defect map. For high-resolution images, scan times can be quite long (1 mm{sup 2} per hour). Single-pixel detection has been used traditionally because of the ease in separating the laser-induced topographical change due to defect absorption from the defect surface topography. This is accomplished by using standard chopper and lock-in amplifier techniques to remove the DC signal. Multi-pixel photothermal microscopy is now possible by utilizing an optical lock-in technique. This eliminates the lock-in amplifier and enables the use of a CCD camera with an optical lock in for each pixel. With this technique, the data acquisition speed can be increased by orders of magnitude depending on laser power, beam size, and pixel density.

  9. An estimation error bound for pixelated sensing

    NASA Astrophysics Data System (ADS)

    Kreucher, Chris; Bell, Kristine

    2016-05-01

    This paper considers the ubiquitous problem of estimating the state (e.g., position) of an object based on a series of noisy measurements. The standard approach is to formulate this problem as one of measuring the state (or a function of the state) corrupted by additive Gaussian noise. This model assumes both (i) the sensor provides a measurement of the true target (or, alternatively, a separate signal processing step has eliminated false alarms), and (ii) The error source in the measurement is accurately described by a Gaussian model. In reality, however, sensor measurement are often formed on a grid of pixels - e.g., Ground Moving Target Indication (GMTI) measurements are formed for a discrete set of (angle, range, velocity) voxels, and EO imagery is made on (x, y) grids. When a target is present in a pixel, therefore, uncertainty is not Gaussian (instead it is a boxcar function) and unbiased estimation is not generally possible as the location of the target within the pixel defines the bias of the estimator. It turns out that this small modification to the measurement model makes traditional bounding approaches not applicable. This paper discusses pixelated sensing in more detail and derives the minimum mean squared error (MMSE) bound for estimation in the pixelated scenario. We then use this error calculation to investigate the utility of using non-thresholded measurements.

  10. Pixels, Blocks of Pixels, and Polygons: Choosing a Spatial Unit for Thematic Accuracy Assessment

    EPA Science Inventory

    Pixels, polygons, and blocks of pixels are all potentially viable spatial assessment units for conducting an accuracy assessment. We develop a statistical population-based framework to examine how the spatial unit chosen affects the outcome of an accuracy assessment. The populati...

  11. Radiation tolerance of CMOS monolithic active pixel sensors with self-biased pixels

    NASA Astrophysics Data System (ADS)

    Deveaux, M.; Amar-Youcef, S.; Besson, A.; Claus, G.; Colledani, C.; Dorokhov, M.; Dritsa, C.; Dulinski, W.; Fröhlich, I.; Goffe, M.; Grandjean, D.; Heini, S.; Himmi, A.; Hu, C.; Jaaskelainen, K.; Müntz, C.; Shabetai, A.; Stroth, J.; Szelezniak, M.; Valin, I.; Winter, M.

    2010-12-01

    CMOS monolithic active pixel sensors (MAPS) are proposed as a technology for various vertex detectors in nuclear and particle physics. We discuss the mechanisms of ionizing radiation damage on MAPS hosting the dead time free, so-called self bias pixel. Moreover, we introduce radiation hardened sensor designs which allow operating detectors after exposing them to irradiation doses above 1 Mrad.

  12. Active Pixel Sensors: Are CCD's Dinosaurs?

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.

    1993-01-01

    Charge-coupled devices (CCD's) are presently the technology of choice for most imaging applications. In the 23 years since their invention in 1970, they have evolved to a sophisticated level of performance. However, as with all technologies, we can be certain that they will be supplanted someday. In this paper, the Active Pixel Sensor (APS) technology is explored as a possible successor to the CCD. An active pixel is defined as a detector array technology that has at least one active transistor within the pixel unit cell. The APS eliminates the need for nearly perfect charge transfer -- the Achilles' heel of CCDs. This perfect charge transfer makes CCD's radiation 'soft,' difficult to use under low light conditions, difficult to manufacture in large array sizes, difficult to integrate with on-chip electronics, difficult to use at low temperatures, difficult to use at high frame rates, and difficult to manufacture in non-silicon materials that extend wavelength response.

  13. Illuminant spectrum estimation at a pixel.

    PubMed

    Ratnasingam, Sivalogeswaran; Hernández-Andrés, Javier

    2011-04-01

    In this paper, an algorithm is proposed to estimate the spectral power distribution of a light source at a pixel. The first step of the algorithm is forming a two-dimensional illuminant invariant chromaticity space. In estimating the illuminant spectrum, generalized inverse estimation and Wiener estimation methods were applied. The chromaticity space was divided into small grids and a weight matrix was used to estimate the illuminant spectrum illuminating the pixels that fall within a grid. The algorithm was tested using a different number of sensor responses to determine the optimum number of sensors for accurate colorimetric and spectral reproduction. To investigate the performance of the algorithm realistically, the responses were multiplied with Gaussian noise and then quantized to 10 bits. The algorithm was tested with standard and measured data. Based on the results presented, the algorithm can be used with six sensors to obtain a colorimetrically good estimate of the illuminant spectrum at a pixel.

  14. Power Studies for the CMS Pixel Tracker

    SciTech Connect

    Todri, A.; Turqueti, M.; Rivera, R.; Kwan, S.; /Fermilab

    2009-01-01

    The Electronic Systems Engineering Department of the Computing Division at the Fermi National Accelerator Laboratory is carrying out R&D investigations for the upgrade of the power distribution system of the Compact Muon Solenoid (CMS) Pixel Tracker at the Large Hadron Collider (LHC). Among the goals of this effort is that of analyzing the feasibility of alternative powering schemes for the forward tracker, including DC to DC voltage conversion techniques using commercially available and custom switching regulator circuits. Tests of these approaches are performed using the PSI46 pixel readout chip currently in use at the CMS Tracker. Performance measures of the detector electronics will include pixel noise and threshold dispersion results. Issues related to susceptibility to switching noise will be studied and presented. In this paper, we describe the current power distribution network of the CMS Tracker, study the implications of the proposed upgrade with DC-DC converters powering scheme and perform noise susceptibility analysis.

  15. Vivid, full-color aluminum plasmonic pixels

    PubMed Central

    Olson, Jana; Manjavacas, Alejandro; Liu, Lifei; Chang, Wei-Shun; Foerster, Benjamin; King, Nicholas S.; Knight, Mark W.; Nordlander, Peter; Halas, Naomi J.; Link, Stephan

    2014-01-01

    Aluminum is abundant, low in cost, compatible with complementary metal-oxide semiconductor manufacturing methods, and capable of supporting tunable plasmon resonance structures that span the entire visible spectrum. However, the use of Al for color displays has been limited by its intrinsically broad spectral features. Here we show that vivid, highly polarized, and broadly tunable color pixels can be produced from periodic patterns of oriented Al nanorods. Whereas the nanorod longitudinal plasmon resonance is largely responsible for pixel color, far-field diffractive coupling is used to narrow the plasmon linewidth, enabling monochromatic coloration and significantly enhancing the far-field scattering intensity of the individual nanorod elements. The bright coloration can be observed with p-polarized white light excitation, consistent with the use of this approach in display devices. The resulting color pixels are constructed with a simple design, are compatible with scalable fabrication methods, and provide contrast ratios exceeding 100:1. PMID:25225385

  16. Towards spark-proof gaseous pixel detectors

    NASA Astrophysics Data System (ADS)

    Tsigaridas, S.; Beuzekom, M. v.; Chan, H. W.; Graaf, H. v. d.; Hartjes, F.; Heijhoff, K.; Hessey, N. P.; Prodanovic, V.

    2016-11-01

    The micro-pattern gaseous pixel detector, is a promising technology for imaging and particle tracking applications. It is a combination of a gas layer acting as detection medium and a CMOS pixelated readout-chip. As a prevention against discharges we deposit a protection layer on the chip and then integrate on top a micromegas-like amplification structure. With this technology we are able to reconstruct 3D track segments of particles passing through the gas thanks to the functionality of the chip. We have turned a Timepix3 chip into a gaseous pixel detector and tested it at the SPS at Cern. The preliminary results are promising and within the expectations. However, the spark protection layer needs further improvement to make reliable detectors. For this reason, we have created a setup for spark-testing. We present the first results obtained from the lab-measurements along with preliminary results from the testbeam.

  17. Pixel lensing observations towards globular clusters

    NASA Astrophysics Data System (ADS)

    Cardone, V. F.; Cantiello, M.

    2003-07-01

    It has been suggested that a monitoring program employing the pixel lensing method to search for microlensing events towards galactic globular clusters may increase the statistics and discriminate among different halo models. Stimulated by this proposal, we evaluate an upper limit to the pixel lensing event rate for such a survey. Four different dark halo models have been considered changing both the flattening and the slope of the mass density profile. The lens mass function has been modelled as a homogenous power - law for mu in (mul, muu) and both the mass limits and the slope of the mass function have been varied to investigate their effect on the rate. The target globular clusters have been selected in order to minimize the disk contribution to the event rate. We find that a pixel lensing survey towards globular clusters is unable to discriminate among different halo models since the number of detectable events is too small to allow any reliable statistical analysis.

  18. SVGA AMOLED with world's highest pixel pitch

    NASA Astrophysics Data System (ADS)

    Prache, Olivier; Wacyk, Ihor

    2006-05-01

    We present the design and early evaluation results of the world's highest pixel pitch full-color 800x3x600- pixel, active matrix organic light emitting diode (AMOLED) color microdisplay for consumer and environmentally demanding applications. The design premises were aimed at improving small area uniformity as well as reducing the pixel size while expanding the functionality found in existing eMagin Corporations' microdisplay products without incurring any power consumption degradation when compared to existing OLED microdisplays produced by eMagin. The initial results of the first silicon prototype presented here demonstrate compliance with all major objectives as well as the validation of a new adaptive gamma correction technique that can operate automatically over temperature.

  19. Modulation transfer function of a trapezoidal pixel array detector

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Guo, Rongli; Ni, Jinping; Dong, Tao

    2016-01-01

    The modulation transfer function (MTF) is the tool most commonly used for quantifying the performance of an electro-optical imaging system. Recently, trapezoid-shaped pixels were designed and used in a retina-like sensor in place of rectangular-shaped pixels. The MTF of a detector with a trapezoidal pixel array is determined according to its definition. Additionally, the MTFs of detectors with differently shaped pixels, but the same pixel areas, are compared. The results show that the MTF values of the trapezoidal pixel array detector are obviously larger than those of rectangular and triangular pixel array detectors at the same frequencies.

  20. Visible light imaging sensor with A/D conversion at the pixel

    NASA Astrophysics Data System (ADS)

    Mandl, William J.

    1999-04-01

    MOSAD, provides a low power on focal pane analog to digital, A/D, process. In this approach, an oversample A/D is placed at each pixel site, with resultant benefits to response linearity and noise performance. An architecture for a visible light imaging sensor using silicon charge well detection was developed for application into video conferencing. There are a total of 76,800 A/D's on the chip. The devise is a monolithic integrated circuit that includes the sensors, A/D's and readout circuitry. A production 1.2 micron CCD/CMOS process was used in it construction. The array was designed with a 320 X 240 format with the pixels placed on 16 micron centers. There was negligible impact on the pixel area due to the A/D such that a fill factor of 67 percent was achieved with front side illumination. On chip power consumption is under 15 milliwatts. Pixels are read in the same manner as accessing the bit locations of a DRAM. As each row of pixels are accessed, they put ones or zeros on the output column that are sensed and passed onto the output buss. The A/D design is based on the patented MOSAD technology, It uses charge well switching at the pixel to convert the accumulated analog signal to digital data. Because of its high noise immunity, no pixel buffer amplifier is required, thus preserving fill factor. Another unique characteristic is the output data format which is directly compatible with Stream Vision, a patented digital display method. This format was adopted to produce a low cost all digital system from camera to display.

  1. K2flix: Kepler pixel data visualizer

    NASA Astrophysics Data System (ADS)

    Barentsen, Geert

    2015-03-01

    K2flix makes it easy to inspect the CCD pixel data obtained by NASA's Kepler space telescope. The two-wheeled extended Kepler mission, K2, is affected by new sources of systematics, including pointing jitter and foreground asteroids, that are easier to spot by eye than by algorithm. The code takes Kepler's Target Pixel Files (TPF) as input and turns them into contrast-stretched animated gifs or MPEG-4 movies. K2flix can be used both as a command-line tool or using its Python API.

  2. Commissioning of the ATLAS pixel detector

    SciTech Connect

    ATLAS Collaboration; Golling, Tobias

    2008-09-01

    The ATLAS pixel detector is a high precision silicon tracking device located closest to the LHC interaction point. It belongs to the first generation of its kind in a hadron collider experiment. It will provide crucial pattern recognition information and will largely determine the ability of ATLAS to precisely track particle trajectories and find secondary vertices. It was the last detector to be installed in ATLAS in June 2007, has been fully connected and tested in-situ during spring and summer 2008, and is ready for the imminent LHC turn-on. The highlights of the past and future commissioning activities of the ATLAS pixel system are presented.

  3. Physics performance of the ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Tsuno, S.

    2017-01-01

    In preparation for LHC Run-2 the ATLAS detector introduced a new pixel detector, the Insertable B-Layer (IBL). This detector is located between the beampipe and what was the innermost pixel layer. The tracking and vertex reconstruction are significantly improved and good performance is expected in high level objects such a b-quark jet tagging. This in turn, leads to better physics results. This note summarizes the impact of the IBL detector on physics results, especially focusing on the analyses using b-quark jets throughout 2016 summer physics program.

  4. From hybrid to CMOS pixels ... a possibility for LHC's pixel future?

    NASA Astrophysics Data System (ADS)

    Wermes, N.

    2015-12-01

    Hybrid pixel detectors have been invented for the LHC to make tracking and vertexing possible at all in LHC's radiation intense environment. The LHC pixel detectors have meanwhile very successfully fulfilled their promises and R&D for the planned HL-LHC upgrade is in full swing, targeting even higher ionising doses and non-ionising fluences. In terms of rate and radiation tolerance hybrid pixels are unrivaled. But they have disadvantages as well, most notably material thickness, production complexity, and cost. Meanwhile also active pixel sensors (DEPFET, MAPS) have become real pixel detectors but they would by far not stand the rates and radiation faced from HL-LHC. New MAPS developments, so-called DMAPS (depleted MAPS) which are full CMOS-pixel structures with charge collection in a depleted region have come in the R&D focus for pixels at high rate/radiation levels. This goal can perhaps be realised exploiting HV technologies, high ohmic substrates and/or SOI based technologies. The paper covers the main ideas and some encouraging results from prototyping R&D, not hiding the difficulties.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

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

    2017-01-01

    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. PMID:28303936

  7. Dynamic holography using pixelated light modulators.

    PubMed

    Zwick, Susanne; Haist, Tobias; Warber, Michael; Osten, Wolfgang

    2010-09-01

    Dynamic holography using spatial light modulators is a very flexible technique that offers various new applications compared to static holography. We give an overview on the technical background of dynamic holography focusing on pixelated spatial light modulators and their technical restrictions, and we present a selection of the numerous applications of dynamic holography.

  8. Spatially Locating FIA Plots from Pixel Values

    Treesearch

    Greg C. Liknes; Geoffrey R. Holden; Mark D. Nelson; Ronald E. McRoberts

    2005-01-01

    The USDA Forest Service Forest Inventory and Analysis (FIA) program is required to ensure the confidentiality of the geographic locations of plots. To accommodate user requests for data without releasing actual plot coordinates, FIA creates overlays of plot locations on various geospatial data, including satellite imagery. Methods for reporting pixel values associated...

  9. JPL CMOS Active Pixel Sensor Technology

    NASA Technical Reports Server (NTRS)

    Fossum, E. R.

    1995-01-01

    This paper will present the JPL-developed complementary metal- oxide-semiconductor (CMOS) active pixel sensor (APS) technology. The CMOS APS has achieved performance comparable to charge coupled devices, yet features ultra low power operation, random access readout, on-chip timing and control, and on-chip analog to digital conversion. Previously published open literature will be reviewed.

  10. Pixel telescope test in STAR at RHIC

    NASA Astrophysics Data System (ADS)

    Sun, Xiangming; Szelezniak, Michal; Greiner, Leo; Matis, Howard; Vu, Chinh; Stezelberger, Thorsten; Wieman, Howard

    2007-10-01

    The STAR experiment at RHIC is designing a new inner vertex detector called the Heavy Flavor Tracker (HFT). The HFT's innermost two layers is called the PIXEL detector which uses Monolithic Active Pixel Sensor technology (MAPS). To test the MAPS technology, we just constructed and tested a telescope. The telescope uses a stack of three MIMOSTAR2 chips, Each MIMOSTAR2 sensor, which was designed by IPHC, is an array of 132x128 pixels with a square pixel size of 30 μ. The readout of the telescope makes use of the ALICE DDL/SIU cards, which is compatible with the future STAR data acquisition system called DAQ1000. The telescope was first studied in a 1.2 GeV/c electron beam at LBNL's Advanced Light Source. Afterwards, the telescope was outside the STAR magnet, and then later inside it, 145 cm away from STAR's center. We will describe this first test of MAPS technology in a collider environment, and report on the occupancy, particle flux, and performance of the telescope.

  11. Uncooled infrared detectors toward smaller pixel pitch with newly proposed pixel structure

    NASA Astrophysics Data System (ADS)

    Tohyama, Shigeru; Sasaki, Tokuhito; Endoh, Tsutomu; Sano, Masahiko; Kato, Koji; Kurashina, Seiji; Miyoshi, Masaru; Yamazaki, Takao; Ueno, Munetaka; Katayama, Haruyoshi; Imai, Tadashi

    2013-12-01

    An uncooled infrared (IR) focal plane array (FPA) with 23.5 μm pixel pitch has been successfully demonstrated and has found wide commercial applications in the areas of thermography, security cameras, and other applications. One of the key issues for uncooled IRFPA technology is to shrink the pixel pitch because the size of the pixel pitch determines the overall size of the FPA, which, in turn, determines the cost of the IR camera products. This paper proposes an innovative pixel structure with a diaphragm and beams placed in different levels to realize an uncooled IRFPA with smaller pixel pitch (≦17 μm). The upper level consists of a diaphragm with VOx bolometer and IR absorber layers, while the lower level consists of the two beams, which are designed to be placed on the adjacent pixels. The test devices of this pixel design with 12, 15, and 17 μm pitch have been fabricated on the Si read-out integrated circuit (ROIC) of quarter video graphics array (QVGA) (320×240) with 23.5 μm pitch. Their performances are nearly equal to those of the IRFPA with 23.5 μm pitch. For example, a noise equivalent temperature difference of 12 μm pixel is 63.1 mK for F/1 optics with the thermal time constant of 14.5 ms. Then, the proposed structure is shown to be effective for the existing IRFPA with 23.5 μm pitch because of the improvements in IR sensitivity. Furthermore, the advanced pixel structure that has the beams composed of two levels are demonstrated to be realizable.

  12. Gallium arsenide pixel detectors for medical imaging

    NASA Astrophysics Data System (ADS)

    Da Via, C.; Bates, R.; Bertolucci, E.; Bottigli, U.; Campbell, M.; Chesi, E.; Conti, M.; D'Auria, S.; DelPapa, C.; Fantacci, M. E.; Grossi, G.; Heijne, E.; Mancini, E.; Middelkamp, P.; Raine, C.; Russo, P.; O'Shea, V.; Scharfetter, L.; Smith, K.; Snoeys, W.; Stefanini, A.

    1997-08-01

    Gallium arsenide pixel detectors processed on a 200 μm Semi-Insulating (SI) Hitachi substrate were bump-bonded to the Omega3 electronics developed at CERN for high energy physics [1]. The pixel dimensions are 50 μm × 500 μm for a total of 2048 cells and an active area of ˜0.5 cm 2. Our aim is to use this system for medical imaging. We report the results obtained after irradiation of the detector with different X-ray sources on phantoms with different contrasts. The system showed good sensitivity to X-rays from 241Am (60 keV) and 109Cd (22.1 keV). It is also sensitive to β- particles from 90Sr as well as from 32P which is used as a tracer for autoradiography applications. The inherent high absorption efficiency of GaAs associated with the self-triggering capabilities of the pixel readout system reduced considerably the acquisition time compared with traditional systems based on silicon or emulsions. The present configuration is not optimised for X-ray imaging. The reduction of the pixel dimensions to 200 μm × 200 μm together with the integration of a counter in the pixel electronics would make the detector competitive for applications like mammography or dental radiology. For certain applications in biochemistry, such as DNA sequencing, where good spatial resolution is required only in one direction, the present setup should allow the best spatial resolution available up to now with respect to other digital autoradiographic systems. DNA sequencing tests are now under way.

  13. Adaptive bad pixel correction algorithm for IRFPA based on PCNN

    NASA Astrophysics Data System (ADS)

    Leng, Hanbing; Zhou, Zuofeng; Cao, Jianzhong; Yi, Bo; Yan, Aqi; Zhang, Jian

    2013-10-01

    Bad pixels and response non-uniformity are the primary obstacles when IRFPA is used in different thermal imaging systems. The bad pixels of IRFPA include fixed bad pixels and random bad pixels. The former is caused by material or manufacture defect and their positions are always fixed, the latter is caused by temperature drift and their positions are always changing. Traditional radiometric calibration-based bad pixel detection and compensation algorithm is only valid to the fixed bad pixels. Scene-based bad pixel correction algorithm is the effective way to eliminate these two kinds of bad pixels. Currently, the most used scene-based bad pixel correction algorithm is based on adaptive median filter (AMF). In this algorithm, bad pixels are regarded as image noise and then be replaced by filtered value. However, missed correction and false correction often happens when AMF is used to handle complex infrared scenes. To solve this problem, a new adaptive bad pixel correction algorithm based on pulse coupled neural networks (PCNN) is proposed. Potential bad pixels are detected by PCNN in the first step, then image sequences are used periodically to confirm the real bad pixels and exclude the false one, finally bad pixels are replaced by the filtered result. With the real infrared images obtained from a camera, the experiment results show the effectiveness of the proposed algorithm.

  14. Thermal Design of the Cassini Narrow Angle Camera

    NASA Technical Reports Server (NTRS)

    Hoffman, Pamela

    1994-01-01

    The Narrow Angle Camera (NAC) is one of two cameras in the Imaging Science Subsystem (ISS) on the Cassini Spacecraft (S/C), the second camera is a Voyager-inherited Wide Angle Camera (WAC). Cassini is currently planned to be launched in October 1997 and will arrive at Saturn for a four year tour in June 2004. The Narrow Angle Optics are a Ritchey Chretien type Optics, has a focal length of 2000 mm, a relative aperture of f/10.5, a spectral range of 200 to 1100 nm, 24 filters, a pixel field of view of 6.0 microradian/pixel, and has a field of view of 3.5 x 3.5 degrees. The sensor is a Charged Couple Device (CCD), 1024 x 1024 pixels with a pixel size of 12 x 12 um, a full well greater than 50,000 e-, on chip processing of up to 800,000 e- pixel summation, a dark current of less than 0.1 e-/pixel/sec at operating temperature, and a charge transfer efficiency of 0.99999 at operating temperature...

  15. Direct read-out CMOS camera with applications to full-field optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Egan, Patrick; Lakestani, Fereydoun; Whelan, Maurice P.; Connelly, Michael J.

    2005-06-01

    A comprehensive characterisation of a complementary metal-oxide semiconductor (CMOS) and digital signal processor (DSP) camera, used typically in machine vision applications, is presented in this paper. The camera consists of a direct read-out CMOS sensor, each pixel giving a direct analogue voltage output related to light intensity, with an analogue-to-digital converter and digital signal processor on the back-end. The camera operates as a stand-alone device using a VGA display; code being pre-programmed to the onboard random access memory of the DSP. High detection rates (kHz) on multiple pixels were achieved, and the relationship between pixel response time and light intensity was quantified. The CMOS sensor, with 1024x1024 pixels randomly addressable in space and time, demonstrated a dynamic logarithmic light intensity sensitivity range of 120dB. Integrating the CMOS camera with a low coherence Michelson interferometer, optical coherence tomography (OCT) axial depth scans have been acquired. The intended application is an imaging device for simple yet functional full-field optical coherence tomography. The advantages of the CMOS sensor are the potential for carrier-based detection, through the very fast pixel response with under-sampling, and the elimination of the electromechanical lateral scanning of conventional OCT by replacing it with electronic pixel scanning.

  16. Design Methodology: ASICs with complex in-pixel processing for Pixel Detectors

    SciTech Connect

    Fahim, Farah

    2014-10-31

    The development of Application Specific Integrated Circuits (ASIC) for pixel detectors with complex in-pixel processing using Computer Aided Design (CAD) tools that are, themselves, mainly developed for the design of conventional digital circuits requires a specialized approach. Mixed signal pixels often require parasitically aware detailed analog front-ends and extremely compact digital back-ends with more than 1000 transistors in small areas below 100μm x 100μm. These pixels are tiled to create large arrays, which have the same clock distribution and data readout speed constraints as in, for example, micro-processors. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout.

  17. Dependence of the appearance-based perception of criminality, suggestibility, and trustworthiness on the level of pixelation of facial images.

    PubMed

    Nurmoja, Merle; Eamets, Triin; Härma, Hanne-Loore; Bachmann, Talis

    2012-10-01

    While the dependence of face identification on the level of pixelation-transform of the images of faces has been well studied, similar research on face-based trait perception is underdeveloped. Because depiction formats used for hiding individual identity in visual media and evidential material recorded by surveillance cameras often consist of pixelized images, knowing the effects of pixelation on person perception has practical relevance. Here, the results of two experiments are presented showing the effect of facial image pixelation on the perception of criminality, trustworthiness, and suggestibility. It appears that individuals (N = 46, M age = 21.5 yr., SD = 3.1 for criminality ratings; N = 94, M age = 27.4 yr., SD = 10.1 for other ratings) have the ability to discriminate between facial cues ndicative of these perceived traits from the coarse level of image pixelation (10-12 pixels per face horizontally) and that the discriminability increases with a decrease in the coarseness of pixelation. Perceived criminality and trustworthiness appear to be better carried by the pixelized images than perceived suggestibility.

  18. WFC3/IR Cycle 19 Bad Pixel Table Update

    NASA Astrophysics Data System (ADS)

    Hilbert, B.

    2012-06-01

    Using data from Cycles 17, 18, and 19, we have updated the IR channel bad pixel table for WFC3. The bad pixel table contains flags that mark the position of pixels that are dead, unstable, have a bad zeroth read value, or are affected by "blobs". In all, 28,500 of the science pixels (2.77%) are flagged as bad. Observers are encouraged to dither their observations as a means of lessening the effects of these bad pixels. The new bad pixel table is in the calibration database system (CDBS) as w681807ii_bpx.fits.

  19. Design methodology: edgeless 3D ASICs with complex in-pixel processing for pixel detectors

    SciTech Connect

    Fahim Farah, Fahim Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-28

    The design methodology for the development of 3D integrated edgeless pixel detectors with in-pixel processing using Electronic Design Automation (EDA) tools is presented. A large area 3 tier 3D detector with one sensor layer and two ASIC layers containing one analog and one digital tier, is built for x-ray photon time of arrival measurement and imaging. A full custom analog pixel is 65μm x 65μm. It is connected to a sensor pixel of the same size on one side, and on the other side it has approximately 40 connections to the digital pixel. A 32 x 32 edgeless array without any peripheral functional blocks constitutes a sub-chip. The sub-chip is an indivisible unit, which is further arranged in a 6 x 6 array to create the entire 1.248cm x 1.248cm ASIC. Each chip has 720 bump-bond I/O connections, on the back of the digital tier to the ceramic PCB. All the analog tier power and biasing is conveyed through the digital tier from the PCB. The assembly has no peripheral functional blocks, and hence the active area extends to the edge of the detector. This was achieved by using a few flavors of almost identical analog pixels (minimal variation in layout) to allow for peripheral biasing blocks to be placed within pixels. The 1024 pixels within a digital sub-chip array have a variety of full custom, semi-custom and automated timing driven functional blocks placed together. The methodology uses a modified mixed-mode on-top digital implementation flow to not only harness the tool efficiency for timing and floor-planning but also to maintain designer control over compact parasitically aware layout. The methodology uses the Cadence design platform, however it is not limited to this tool.

  20. Pixel-by-pixel absolute phase retrieval using three phase-shifted fringe patterns without markers

    NASA Astrophysics Data System (ADS)

    Jiang, Chufan; Li, Beiwen; Zhang, Song

    2017-04-01

    This paper presents a method that can recover absolute phase pixel by pixel without embedding markers on three phase-shifted fringe patterns, acquiring additional images, or introducing additional hardware component(s). The proposed three-dimensional (3D) absolute shape measurement technique includes the following major steps: (1) segment the measured object into different regions using rough priori knowledge of surface geometry; (2) artificially create phase maps at different z planes using geometric constraints of structured light system; (3) unwrap the phase pixel by pixel for each region by properly referring to the artificially created phase map; and (4) merge unwrapped phases from all regions into a complete absolute phase map for 3D reconstruction. We demonstrate that conventional three-step phase-shifted fringe patterns can be used to create absolute phase map pixel by pixel even for large depth range objects. We have successfully implemented our proposed computational framework to achieve absolute 3D shape measurement at 40 Hz.

  1. ACS/WFC Pixel Stability - Bringing the Pixels Back to the Science

    NASA Astrophysics Data System (ADS)

    Borncamp, David; Grogin, Norman A.; Bourque, Matthew; Ogaz, Sara

    2016-06-01

    Electrical current that has been trapped within the lattice structure of a Charged Coupled Device (CCD) can be present through multiple exposures, which will have an adverse effect on its science performance. The traditional way to correct for this extra charge is to take an image with the camera shutter closed periodically throughout the lifetime of the instrument. These images, generally referred to as dark images, allow for the characterization of the extra charge that is trapped within the CCD at the time of observation. This extra current can then be subtracted out of science images to correct for the extra charge that was there at this time. Pixels that have a charge above a certain threshold of current are marked as “hot” and flagged in the data quality array. However, these pixels may not be "bad" in the traditional sense that they cannot be reliably dark-subtracted. If these pixels are shown to be stable over an anneal period, the charge can be properly subtracted and the extra noise from this dark current can be taken into account. We present the results of a pixel history study that analyzes every pixel of ACS/WFC individually and allows pixels that were marked as bad to be brought back into the science image.

  2. Monolithic pixel detectors for high energy physics

    NASA Astrophysics Data System (ADS)

    Snoeys, W.

    2013-12-01

    Monolithic pixel detectors integrating sensor matrix and readout in one piece of silicon have revolutionized imaging for consumer applications, but despite years of research they have not yet been widely adopted for high energy physics. Two major requirements for this application, radiation tolerance and low power consumption, require charge collection by drift for the most extreme radiation levels and an optimization of the collected signal charge over input capacitance ratio (Q/C). It is shown that monolithic detectors can achieve Q/C for low analog power consumption and even carryout the promise to practically eliminate analog power consumption, but combining sufficient Q/C, collection by drift, and integration of readout circuitry within the pixel remains a challenge. An overview is given of different approaches to address this challenge, with possible advantages and disadvantages.

  3. On the accuracy of pixel relaxation labeling

    NASA Technical Reports Server (NTRS)

    Richards, J. A.; Landgrebe, D. A.; Swain, P. H.

    1981-01-01

    An analysis of pixel labeling by probabilistic relaxation techniques is presented to demonstrate that these labeling procedures degenerate to weighted averages in the vicinity of fixed points. A consequence of this is that undesired label conversions can occur, leading to a deterioration of labeling accuracy at a stage after an improvement has already been achieved. Means for overcoming the accuracy deterioration are suggested and used as the basis for a possible design strategy for using probabilistic relaxation procedures. The results obtained are illustrated using simple data sets in which labeling on individual pixels can be examined and also using Landsat imagery to show application to data typical of that encountered in remote sensing applications.

  4. Active pixel array devices in space missions

    NASA Astrophysics Data System (ADS)

    Hopkinson, G. R.; Purll, D. J.; Abbey, A. F.; Short, A.; Watson, D. J.; Wells, A.

    2003-11-01

    The X-ray Telescope for NASA's Swift mission incorporates a Telescope Alignment Monitor (TAM) to measure thermo-elastic misalignments between the telescope and the spacecraft star tracker. A LED in the X-ray focal plane is imaged on to a position-sensitive detector via two paths, directly and after reflection from the star tracker alignment cube. The separation of the two spots of light on the detector is determined with sub-pixel accuracy using a centroiding algorithm. The active element of the TAM is a miniature camera supplied by Sira Electro-Optics Ltd, using an Active Pixel Sensor (APS). The camera was based on similar pointing sensors developed on European Space Agency programmes, such as acquisition sensors for optical inter-satellite links and miniaturized star trackers. The paper gives the background to APS-based pointing sensors, describes the Swift TAM system, and presents test results from the instrument development programme.

  5. MTF evaluation of white pixel sensors

    NASA Astrophysics Data System (ADS)

    Lindner, Albrecht; Atanassov, Kalin; Luo, Jiafu; Goma, Sergio

    2015-01-01

    We present a methodology to compare image sensors with traditional Bayer RGB layouts to sensors with alternative layouts containing white pixels. We focused on the sensors' resolving powers, which we measured in the form of a modulation transfer function for variations in both luma and chroma channels. We present the design of the test chart, the acquisition of images, the image analysis, and an interpretation of results. We demonstrate the approach at the example of two sensors that only differ in their color filter arrays. We confirmed that the sensor with white pixels and the corresponding demosaicing result in a higher resolving power in the luma channel, but a lower resolving power in the chroma channels when compared to the traditional Bayer sensor.

  6. pPXF: Penalized Pixel-Fitting stellar kinematics extraction

    NASA Astrophysics Data System (ADS)

    Cappellari, Michele

    2012-10-01

    pPXF is an IDL (and free GDL or FL) program which extracts the stellar kinematics or stellar population from absorption-line spectra of galaxies using the Penalized Pixel-Fitting method (pPXF) developed by Cappellari & Emsellem (2004, PASP, 116, 138). Additional features implemented in the pPXF routine include: Optimal template: Fitted together with the kinematics to minimize template-mismatch errors. Also useful to extract gas kinematics or derive emission-corrected line-strengths indexes. One can use synthetic templates to study the stellar population of galaxies via "Full Spectral Fitting" instead of using traditional line-strengths.Regularization of templates weights: To reduce the noise in the recovery of the stellar population parameters and attach a physical meaning to the output weights assigned to the templates in term of the star formation history (SFH) or metallicity distribution of an individual galaxy.Iterative sigma clipping: To clean the spectra from residual bad pixels or cosmic rays.Additive/multiplicative polynomials: To correct low frequency continuum variations. Also useful for calibration purposes.

  7. Pixel-based OPC optimization based on conjugate gradients.

    PubMed

    Ma, Xu; Arce, Gonzalo R

    2011-01-31

    Optical proximity correction (OPC) methods are resolution enhancement techniques (RET) used extensively in the semiconductor industry to improve the resolution and pattern fidelity of optical lithography. In pixel-based OPC (PBOPC), the mask is divided into small pixels, each of which is modified during the optimization process. Two critical issues in PBOPC are the required computational complexity of the optimization process, and the manufacturability of the optimized mask. Most current OPC optimization methods apply the steepest descent (SD) algorithm to improve image fidelity augmented by regularization penalties to reduce the complexity of the mask. Although simple to implement, the SD algorithm converges slowly. The existing regularization penalties, however, fall short in meeting the mask rule check (MRC) requirements often used in semiconductor manufacturing. This paper focuses on developing OPC optimization algorithms based on the conjugate gradient (CG) method which exhibits much faster convergence than the SD algorithm. The imaging formation process is represented by the Fourier series expansion model which approximates the partially coherent system as a sum of coherent systems. In order to obtain more desirable manufacturability properties of the mask pattern, a MRC penalty is proposed to enlarge the linear size of the sub-resolution assistant features (SRAFs), as well as the distances between the SRAFs and the main body of the mask. Finally, a projection method is developed to further reduce the complexity of the optimized mask pattern.

  8. Local Histograms for Per-Pixel Classification

    DTIC Science & Technology

    2012-03-01

    Domain-Knowledge-Inspired Math - ematical Framework for the Description and Classification of H&E Stained Histopathology Images,” Proceedings of SPIE, 8138... computed over discrete images as the number of pixels in a particular bin. In order to obtain a “density” independent of the bin-width, one can divide the...Notes in Computer Science , 5112: 688–696 (2008). [12] van Ginneken, Bram and Bart M. ter Haar Romeny. “Applications of Locally Orderless Images

  9. Demonstration of a Polarimeter in a Pixel

    DTIC Science & Technology

    2011-02-15

    Well Infrared Photo- detector ( QWIP ) with gratings at different angles. Annual Progress Report-April 2010...of a single pixel QWIP Polarimeter. 2.2. Growth of Structure Fig.3 Schematic showing the structure of QWIP . 2.3. Modified Fabrication...One side open for Middle contact Next device Ge/Au/Ni/Au/In Ge/Au/Ni/Au Top QWIP Top QWIP Lower QWIP Lower QWIP Underfill Epoxy Top X 50 SI-GaAs

  10. The Silicon Pixel Detector for ALICE Experiment

    SciTech Connect

    Fabris, D.; Bombonati, C.; Dima, R.; Lunardon, M.; Moretto, S.; Pepato, A.; Bohus, L. Sajo; Scarlassara, F.; Segato, G.; Shen, D.; Turrisi, R.; Viesti, G.; Anelli, G.; Boccardi, A.; Burns, M.; Campbell, M.; Ceresa, S.; Conrad, J.; Kluge, A.; Kral, M.

    2007-10-26

    The Inner Tracking System (ITS) of the ALICE experiment is made of position sensitive detectors which have to operate in a region where the track density may be as high as 50 tracks/cm{sup 2}. To handle such densities detectors with high precision and granularity are mandatory. The Silicon Pixel Detector (SPD), the innermost part of the ITS, has been designed to provide tracking information close to primary interaction point. The assembly of the entire SPD has been completed.

  11. Pixel super resolution using wavelength scanning

    DTIC Science & Technology

    2016-04-08

    Journal Article Journal : Light: Science & Applications (Nature Publishing Group) Publication Location: Article Title: Pixel super-resolution using...of a wide-field imaging system and significantly increase its space-bandwidth product . Publication Identifier Type: DOI Issue: 4 Date Published: 12...significantly increase its space-bandwidth product . We confirmed the effectiveness of this new technique by improving the resolution of lens-free as

  12. The Belle II DEPFET pixel detector

    NASA Astrophysics Data System (ADS)

    Moser, Hans-Günther

    2016-09-01

    The Belle II experiment at KEK (Tsukuba, Japan) will explore heavy flavour physics (B, charm and tau) at the starting of 2018 with unprecedented precision. Charged particles are tracked by a two-layer DEPFET pixel device (PXD), a four-layer silicon strip detector (SVD) and the central drift chamber (CDC). The PXD will consist of two layers at radii of 14 mm and 22 mm with 8 and 12 ladders, respectively. The pixel sizes will vary, between 50 μm×(55-60) μm in the first layer and between 50 μm×(70-85) μm in the second layer, to optimize the charge sharing efficiency. These innermost layers have to cope with high background occupancy, high radiation and must have minimal material to reduce multiple scattering. These challenges are met using the DEPFET technology. Each pixel is a FET integrated on a fully depleted silicon bulk. The signal charge collected in the 'internal gate' modulates the FET current resulting in a first stage amplification and therefore very low noise. This allows very thin sensors (75 μm) reducing the overall material budget of the detector (0.21% X0). Four fold multiplexing of the column parallel readout allows read out a full frame of the pixel matrix in only 20 μs while keeping the power consumption low enough for air cooling. Only the active electronics outside the detector acceptance has to be cooled actively with a two phase CO2 system. Furthermore the DEPFET technology offers the unique feature of an electronic shutter which allows the detector to operate efficiently in the continuous injection mode of superKEKB.

  13. Digital Light Box, One Of The Integral Pieces Of PACS

    NASA Astrophysics Data System (ADS)

    Rutherford, Harold G.; Gray, Michael J.

    1983-05-01

    A workable PACS system consists of several discrete assemblies which are linked together by data communication links for terminal and image data input and output. Two phases of development of a PACS system can be identified and labeled: emulation and enhancement. The latter is characterized by the observation "you do that so well, can you also do this?" Emulation, on the other hand, assures an accepted and working system. One of the key components of a PACS system is the emulation of the classical and ubiquitous "lightbox". This paper presents an emulation of the lightbox using a highspeed digital disk and video display on multiple high resolution monitors capable of 1024 x 1024 or 512 x 512 resolution pixel display. The emulation features are: a) loading and reloading in less than one second, b) access to between 800 and 3200 digital radiographs, and c) highspeed review forward and backward through this list of radiographs at rates up to 30 new images/second. Operation is under manual control both in rate and direction. This stresses the speed. The feature which makes this "lightbox" emulation desirable is the ability to dwell on a presently viewable display of digital radiographs with access to previous and following images in the study. One of the features desired in an emulation is that the components be "off the shelf". This means that existing hardware is used in the emulation. Software can then be generated based on known hardware. The emulation has flexibility of size: multi-image displays ranging from 2 or 3 images side by side to the piano-roll type endless display of an array with 4 images side-by-side and 3 rows visible at any one time. In addition, it has flexibility of resolution: radiographs displayable within a 256 x 256 pixel region to those displayable within a 1024 x 1024 pixel array as well as images which are much larger (4000 pixel by 4000 line chest radiograph scans) using a 1024 pixel by 1024 line window into the radiograph. The emulation of

  14. Baryon Acoustic Oscillations reconstruction with pixels

    NASA Astrophysics Data System (ADS)

    Obuljen, Andrej; Villaescusa-Navarro, Francisco; Castorina, Emanuele; Viel, Matteo

    2017-09-01

    Gravitational non-linear evolution induces a shift in the position of the baryon acoustic oscillations (BAO) peak together with a damping and broadening of its shape that bias and degrades the accuracy with which the position of the peak can be determined. BAO reconstruction is a technique developed to undo part of the effect of non-linearities. We present and analyse a reconstruction method that consists of displacing pixels instead of galaxies and whose implementation is easier than the standard reconstruction method. We show that this method is equivalent to the standard reconstruction technique in the limit where the number of pixels becomes very large. This method is particularly useful in surveys where individual galaxies are not resolved, as in 21cm intensity mapping observations. We validate this method by reconstructing mock pixelated maps, that we build from the distribution of matter and halos in real- and redshift-space, from a large set of numerical simulations. We find that this method is able to decrease the uncertainty in the BAO peak position by 30-50% over the typical angular resolution scales of 21 cm intensity mapping experiments.

  15. Status of the CMS pixel project

    SciTech Connect

    Uplegger, Lorenzo; /Fermilab

    2008-01-01

    The Compact Muon Solenoid Experiment (CMS) will start taking data at the Large Hadron Collider (LHC) in 2008. The closest detector to the interaction point is the silicon pixel detector which is the heart of the tracking system. It consists of three barrel layers and two pixel disks on each side of the interaction point for a total of 66 million channels. Its proximity to the interaction point means there will be very large particle fluences and therefore a radiation-tolerant design is necessary. The pixel detector will be crucial to achieve a good vertex resolution and will play a key role in pattern recognition and track reconstruction. The results from test beam runs prove that the expected performances can be achieved. The detector is currently being assembled and will be ready for insertion into CMS in early 2008. During the assembly phase, a thorough electronic test is being done to check the functionality of each channel to guarantee the performance required to achieve the physics goals. This report will present the final detector design, the status of the production as well as results from test beam runs to validate the expected performance.

  16. Pixel electronics for the ATLAS experiment

    NASA Astrophysics Data System (ADS)

    Fischer, P.

    2001-06-01

    The ATLAS experiment at LHC will use 3 barrel layers and 2×5 disks of silicon pixel detectors as the innermost elements of the semiconductor tracker. The basic building blocks are pixel modules with an active area of 16.4 mm×60.8 mm which include an n + on n-type silicon sensor and 16 VLSI front-end (FE) chips. Every FE chip contains a low power, high speed charge sensitive preamplifier, a fast discriminator, and a readout system which operates at the 40 MHz rate of LHC. The addresses of hit pixels (as well as a low resolution pulse height information) are stored on the FE chips until arrival of a level 1 trigger signal. Hits are then transferred to a module controller chip (MCC) which collects the data of all 16 FE chips, builds complete events and sends the data through two optical links to the data acquisition system. The MCC receives clock and data through an additional optical link and provides timing and configuration information for the FE chips. Two additional chips are used to amplify and decode the pin diode signal and to drive the VCSEL laser diodes of the optical links.

  17. Photovoltaic Retinal Prosthesis with High Pixel Density

    PubMed Central

    Mathieson, Keith; Loudin, James; Goetz, Georges; Huie, Philip; Wang, Lele; Kamins, Theodore I.; Galambos, Ludwig; Smith, Richard; Harris, James S.; Sher, Alexander; Palanker, Daniel

    2012-01-01

    Retinal degenerative diseases lead to blindness due to loss of the “image capturing” photoreceptors, while neurons in the “image processing” inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems, which deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation was produced in normal and degenerate rat retinas, with pulse durations from 0.5 to 4 ms, and threshold peak irradiances from 0.2 to 10 mW/mm2, two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 μm bipolar pixel, demonstrating the possibility of a fully-integrated photovoltaic retinal prosthesis with high pixel density. PMID:23049619

  18. Soil moisture variability within remote sensing pixels

    SciTech Connect

    Charpentier, M.A.; Groffman, P.M. )

    1992-11-30

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. This paper addresses the question of soil moisture variation within the field of view of a remote sensing pixel. Remote sensing is the only practical way to sense soil moisture over large areas, but it is known that there can be large variations of soil moisture within the field of view of a pixel. The difficulty with this is that many processes, such as gas exchange between surface and atmosphere can vary dramatically with moisture content, and a small wet spot, for example, can have a dramatic impact on such processes, and thereby bias remote sensing data results. Here the authors looked at the impact of surface topography on the level of soil moisture, and the interaction of both on the variability of soil moisture sensed by a push broom microwave radiometer (PBMR). In addition the authors looked at the question of whether variations of soil moisture within pixel size areas could be used to assign errors to PBMR generated soil moisture data.

  19. Photovoltaic retinal prosthesis with high pixel density

    NASA Astrophysics Data System (ADS)

    Mathieson, Keith; Loudin, James; Goetz, Georges; Huie, Philip; Wang, Lele; Kamins, Theodore I.; Galambos, Ludwig; Smith, Richard; Harris, James S.; Sher, Alexander; Palanker, Daniel

    2012-06-01

    Retinal degenerative diseases lead to blindness due to loss of the `image capturing' photoreceptors, while neurons in the `image-processing' inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating the surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems that deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation is produced in normal and degenerate rat retinas, with pulse durations of 0.5-4 ms, and threshold peak irradiances of 0.2-10 mW mm-2, two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 µm bipolar pixel, demonstrating the possibility of a fully integrated photovoltaic retinal prosthesis with high pixel density.

  20. CMOS Active Pixel Sensor Technology and Reliability Characterization Methodology

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Pain, Bedabrata; Kayaii, Sammy

    2006-01-01

    This paper describes the technology, design features and reliability characterization methodology of a CMOS Active Pixel Sensor. Both overall chip reliability and pixel reliability are projected for the imagers.

  1. Effect of mixed (boundary) pixels on crop proportion estimation

    NASA Technical Reports Server (NTRS)

    Chhikara, R. S.

    1984-01-01

    In estimating acreage proportions of crop types in a segment using Landsat data, considerable problem is caused by the presence of mixed pixels. Due to lack of understanding of their spectral characteristics, mixed pixels have been treated in the past as pure while clustering and classifying the segment data. This paper examines this approach of treating mixed pixels as pure pixels and the effect of mixed pixels on the bias and variance of a crop type proportion estimate. First, the spectral response of a boundary pixel is modeled and an analytical expression for the bias and variance of a proportion estimate is obtained. This is followed by a numerical illustration of the effect of mixed pixels on bias and variance. It is shown that as the size of the mixed pixel class increases in a segment, the variance increases, however, such increase does not always affect the bias of the proportion estimate.

  2. PIXELS: Using field-based learning to investigate students' concepts of pixels and sense of scale

    NASA Astrophysics Data System (ADS)

    Pope, A.; Tinigin, L.; Petcovic, H. L.; Ormand, C. J.; LaDue, N.

    2015-12-01

    Empirical work over the past decade supports the notion that a high level of spatial thinking skill is critical to success in the geosciences. Spatial thinking incorporates a host of sub-skills such as mentally rotating an object, imagining the inside of a 3D object based on outside patterns, unfolding a landscape, and disembedding critical patterns from background noise. In this study, we focus on sense of scale, which refers to how an individual quantified space, and is thought to develop through kinesthetic experiences. Remote sensing data are increasingly being used for wide-reaching and high impact research. A sense of scale is critical to many areas of the geosciences, including understanding and interpreting remotely sensed imagery. In this exploratory study, students (N=17) attending the Juneau Icefield Research Program participated in a 3-hour exercise designed to study how a field-based activity might impact their sense of scale and their conceptions of pixels in remotely sensed imagery. Prior to the activity, students had an introductory remote sensing lecture and completed the Sense of Scale inventory. Students walked and/or skied the perimeter of several pixel types, including a 1 m square (representing a WorldView sensor's pixel), a 30 m square (a Landsat pixel) and a 500 m square (a MODIS pixel). The group took reflectance measurements using a field radiometer as they physically traced out the pixel. The exercise was repeated in two different areas, one with homogenous reflectance, and another with heterogeneous reflectance. After the exercise, students again completed the Sense of Scale instrument and a demographic survey. This presentation will share the effects and efficacy of the field-based intervention to teach remote sensing concepts and to investigate potential relationships between students' concepts of pixels and sense of scale.

  3. Mars Exploration Rover engineering cameras

    USGS Publications Warehouse

    Maki, J.N.; Bell, J.F.; Herkenhoff, K. E.; Squyres, S. W.; Kiely, A.; Klimesh, M.; Schwochert, M.; Litwin, T.; Willson, R.; Johnson, Aaron H.; Maimone, M.; Baumgartner, E.; Collins, A.; Wadsworth, M.; Elliot, S.T.; Dingizian, A.; Brown, D.; Hagerott, E.C.; Scherr, L.; Deen, R.; Alexander, D.; Lorre, J.

    2003-01-01

    NASA's Mars Exploration Rover (MER) Mission will place a total of 20 cameras (10 per rover) onto the surface of Mars in early 2004. Fourteen of the 20 cameras are designated as engineering cameras and will support the operation of the vehicles on the Martian surface. Images returned from the engineering cameras will also be of significant importance to the scientific community for investigative studies of rock and soil morphology. The Navigation cameras (Navcams, two per rover) are a mast-mounted stereo pair each with a 45?? square field of view (FOV) and an angular resolution of 0.82 milliradians per pixel (mrad/pixel). The Hazard Avoidance cameras (Hazcams, four per rover) are a body-mounted, front- and rear-facing set of stereo pairs, each with a 124?? square FOV and an angular resolution of 2.1 mrad/pixel. The Descent camera (one per rover), mounted to the lander, has a 45?? square FOV and will return images with spatial resolutions of ???4 m/pixel. All of the engineering cameras utilize broadband visible filters and 1024 x 1024 pixel detectors. Copyright 2003 by the American Geophysical Union.

  4. HUBBLE SPACE TELESCOPE PIXEL ANALYSIS OF THE INTERACTING FACE-ON SPIRAL GALAXY NGC 5194 (M51A)

    SciTech Connect

    Lee, Joon Hyeop; Kim, Sang Chul; Park, Hong Soo; Ree, Chang Hee; Kyeong, Jaemann; Chung, Jiwon E-mail: sckim@kasi.re.kr E-mail: chr@kasi.re.kr E-mail: jiwon@kasi.re.kr

    2011-10-10

    A pixel analysis is carried out on the interacting face-on spiral galaxy NGC 5194 (M51A), using the Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) images in the F435W, F555W, and F814W (BVI) bands. After 4 x 4 binning of the HST/ACS images to secure a sufficient signal-to-noise ratio for each pixel, we derive several quantities describing the pixel color-magnitude diagram (pCMD) of NGC 5194: blue/red color cut, red pixel sequence parameters, blue pixel sequence parameters, and blue-to-red pixel ratio. The red sequence pixels are mostly older than 1 Gyr, while the blue sequence pixels are mostly younger than 1 Gyr, in their luminosity-weighted mean stellar ages. The color variation in the red pixel sequence from V = 20 mag arcsec{sup -2} to V = 17 mag arcsec{sup -2} corresponds to a metallicity variation of {Delta}[Fe/H] {approx}2 or an optical depth variation of {Delta}{tau}{sub V} {approx} 4 by dust, but the actual sequence is thought to originate from the combination of those two effects. At V < 20 mag arcsec{sup -2}, the color variation in the blue pixel sequence corresponds to an age variation from 5 Myr to 300 Myr under the assumption of solar metallicity and {tau}{sub V} = 1. To investigate the spatial distributions of stellar populations, we divide pixel stellar populations using the pixel color-color diagram and population synthesis models. As a result, we find that the pixel population distributions across the spiral arms agree with a compressing process by spiral density waves: dense dust {yields} newly formed stars. The tidal interaction between NGC 5194 and NGC 5195 appears to enhance the star formation at the tidal bridge connecting the two galaxies. We find that the pixels corresponding to the central active galactic nucleus (AGN) area of NGC 5194 show a tight sequence at the bright-end of the pCMD, which are in the region of R {approx} 100 pc and may be a photometric indicator of AGN properties.

  5. Measurements with MÖNCH, a 25 μm pixel pitch hybrid pixel detector

    NASA Astrophysics Data System (ADS)

    Ramilli, M.; Bergamaschi, A.; Andrae, M.; Brückner, M.; Cartier, S.; Dinapoli, R.; Fröjdh, E.; Greiffenberg, D.; Hutwelker, T.; Lopez-Cuenca, C.; Mezza, D.; Mozzanica, A.; Ruat, M.; Redford, S.; Schmitt, B.; Shi, X.; Tinti, G.; Zhang, J.

    2017-01-01

    MÖNCH is a hybrid silicon pixel detector based on charge integration and with analog readout, featuring a pixel size of 25×25 μm2. The latest working prototype consists of an array of 400×400 identical pixels for a total active area of 1×1 cm2. Its design is optimized for the single photon regime. An exhaustive characterization of this large area prototype has been carried out in the past months, and it confirms an ENC in the order of 35 electrons RMS and a dynamic range of ~4×12 keV photons in high gain mode, which increases to ~100×12 keV photons with the lowest gain setting. The low noise levels of MÖNCH make it a suitable candidate for X-ray detection at energies around 1 keV and below. Imaging applications in particular can benefit significantly from the use of MÖNCH: due to its extremely small pixel pitch, the detector intrinsically offers excellent position resolution. Moreover, in low flux conditions, charge sharing between neighboring pixels allows the use of position interpolation algorithms which grant a resolution at the micrometer-level. Its energy reconstruction and imaging capabilities have been tested for the first time at a low energy beamline at PSI, with photon energies between 1.75 keV and 3.5 keV, and results will be shown.

  6. ACS/WFC Pixel History, Bringing the Pixels Back to Science

    NASA Astrophysics Data System (ADS)

    Borncamp, David; Grogin, Norman; Bourque, Matthew; Ogaz, Sara

    2017-06-01

    Excess thermal energy within a Charged Coupled Device (CCD) results in excess electrical current that is trapped within the lattice structure of the electronics. This excess signal from the CCD itself can be present through multiple exposures, which will have an adverse effect on its science performance unless it is corrected for. The traditional way to correct for this extra charge is to take occasional long-exposure images with the camera shutter closed. These images, generally referred to as ``dark'' images, allow for the measurement of thermal-electron contamination at each pixel of the CCD. This so-called ``dark current'' can then be subtracted from the science images by re-scaling to the science exposure times. Pixels that have signal above a certain value are traditionally marked as ``hot'' and flagged in the data quality array. Many users will discard these pixels as being bad. However, these pixels may not be bad in the sense that they cannot be reliably dark-subtracted; if these pixels are shown to be stable over a given anneal period, the charge can be properly subtracted and the extra Poisson noise from this dark current can be taken into account and put into the error arrays.

  7. Active pixel sensor pixel having a photodetector whose output is coupled to an output transistor gate

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Nakamura, Junichi (Inventor); Kemeny, Sabrina E. (Inventor)

    2005-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. A Simple Floating Gate (SFG) pixel structure could also be employed in the imager to provide a non-destructive readout and smaller pixel sizes.

  8. Detection and evaluation of mixed pixels in Landsat agricultural scenes

    NASA Technical Reports Server (NTRS)

    Merickel, M. B.; Lundgren, J. C.; Lennington, R. K.

    1982-01-01

    A major problem area encountered in the identification and estimation of agricultural crop proportions in Landsat imagery involves the large proportion of the pixels which are mixed pixels, whose spectral response is influenced by more than one ground cover type. The development of methods for the detection and estimation of crop proportions in mixed pixels is presently reported. The procedure designated CASCADE, based on the estimation of the gradient image for the detection of mixed pixels, considers the consequences of a linear mixing model and is found to provide a method for the allocation of mixed pixels to the surrounding homogeneous region.

  9. How many pixels does it take to make a good 4"×6" print? Pixel count wars revisited

    NASA Astrophysics Data System (ADS)

    Kriss, Michael A.

    2011-01-01

    In the early 1980's the future of conventional silver-halide photographic systems was of great concern due to the potential introduction of electronic imaging systems then typified by the Sony Mavica analog electronic camera. The focus was on the quality of film-based systems as expressed in the number of equivalent number pixels and bits-per-pixel, and how many pixels would be required to create an equivalent quality image from a digital camera. It was found that 35-mm frames, for ISO 100 color negative film, contained equivalent pixels of 12 microns for a total of 18 million pixels per frame (6 million pixels per layer) with about 6 bits of information per pixel; the introduction of new emulsion technology, tabular AgX grains, increased the value to 8 bit per pixel. Higher ISO speed films had larger equivalent pixels, fewer pixels per frame, but retained the 8 bits per pixel. Further work found that a high quality 3.5" x 5.25" print could be obtained from a three layer system containing 1300 x 1950 pixels per layer or about 7.6 million pixels in all. In short, it became clear that when a digital camera contained about 6 million pixels (in a single layer using a color filter array and appropriate image processing) that digital systems would challenge and replace conventional film-based system for the consumer market. By 2005 this became the reality. Since 2005 there has been a "pixel war" raging amongst digital camera makers. The question arises about just how many pixels are required and are all pixels equal? This paper will provide a practical look at how many pixels are needed for a good print based on the form factor of the sensor (sensor size) and the effective optical modulation transfer function (optical spread function) of the camera lens. Is it better to have 16 million, 5.7-micron pixels or 6 million 7.8-micron pixels? How does intrinsic (no electronic boost) ISO speed and exposure latitude vary with pixel size? A systematic review of these issues will

  10. Dynamical pixel manipulation of metasurfaces (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhong, Jin-Qian

    2017-05-01

    Two-dimensional (2D) metamaterials or known as metasurfaces have attracted researchers' attention due to their capability to manipulate the amplitudes, phases and polarization states of incident electromagnetic waves by conferring extra phase different phase at different positions through a super cell that is composed of different oriented structures. In other words, metasurfaces can achieve beam steering and wave shaping by imparting local, gradient phase shift to the incoming waves. With these abilities, metasurfaces can be applied to applications such as ultrathin invisibility cloaks, metasurface holograms, planar lenses and a vortex generator. With the above mentioned advantages and applications of metasurfaces, yet, all the demonstrated metasurfaces possess a main insufficiency that once the metasurfaces are designed and fabricated, their optical properties are then fixed without any chance for further manipulation, which limits their versatility in practical applications. Moreover, although some researchers employed dynamically changeable materials to achieve an active metasurface, such manipulation can only change the overall performance such as an operating frequency instead of changing the provided phase on each pixel of a metasurface. To solve this issue, we employ liquid crystal integrated with a metasurface and the combination could be thus be dynamically tuned via electric bias on each pixel of liquid crystals. Through this setup, we can alter the polarization state of the incident electromagnetic wave dynamically and thus manipulate the extra phase provided by each pixel. In this combination, liquid crystal is employed to change the incident polarization from 0 to 360-degree and the metasurface is designed to achieve four different output signals including phase modulated linear- and circular-polarized light and amplitude-modulated linear- and circular-polarized light. Meanwhile, the metasurfaces could also control the transmission efficiency of the

  11. Small pixel uncooled imaging FPAs and applications

    NASA Astrophysics Data System (ADS)

    Blackwell, Richard; Franks, Glen; Lacroix, Daniel; Hyland, Sandra; Murphy, Robert

    2010-04-01

    BAE Systems continues to make dramatic progress in uncooled microbolometer sensors and applications. This paper will review the latest advancements in microbolometer technology at BAE Systems, including the development status of 17 micrometer pixel pitch detectors and imaging modules which are entering production and will be finding their way into BAE Systems products and applications. Benefits include increased die per wafer and potential benefits to SWAP for many applications. Applications include thermal weapons sights, thermal imaging modules for remote weapon stations, vehicle situational awareness sensors and mast/pole mounted sensors.

  12. Pixel-Level Simulation of Imaging Data

    NASA Astrophysics Data System (ADS)

    Stoughton, C.; Kuropatkin, N. P.; Neilsen, E., Jr.; Harms, D. C.

    2007-10-01

    We are preparing a set of Java packages to facilitate the design and operation of imaging surveys. The packages use shapelets to describe shapes of astronomical sources, optical distortions, and shear from weak gravitational lensing. We introduce noise, bad pixels, cosmic rays, the pupil image, saturation, and other observational effects. A set of utility classes handles I/O, plotting, and interfaces to existing packages: nom.tam.fits for FITS I/O; uk.ac.starlink.table for tables; and cern.colt for algorithms. The packages have been used to generate images for the Dark Energy Survey data challenges, and will be used by SNAP to continue evaluating its design.

  13. Active pixel sensor array with electronic shuttering

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor)

    2002-01-01

    An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

  14. A new 9T global shutter pixel with CDS technique

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Ma, Cheng; Zhou, Quan; Wang, Xinyang

    2015-04-01

    Benefiting from motion blur free, Global shutter pixel is very widely used in the design of CMOS image sensors for high speed applications such as motion vision, scientifically inspection, etc. In global shutter sensors, all pixel signal information needs to be stored in the pixel first and then waiting for readout. For higher frame rate, we need very fast operation of the pixel array. There are basically two ways for the in pixel signal storage, one is in charge domain, such as the one shown in [1], this needs complicated process during the pixel fabrication. The other one is in voltage domain, one example is the one in [2], this pixel is based on the 4T PPD technology and normally the driving of the high capacitive transfer gate limits the speed of the array operation. In this paper we report a new 9T global shutter pixel based on 3-T partially pinned photodiode (PPPD) technology. It incorporates three in-pixel storage capacitors allowing for correlated double sampling (CDS) and pipeline operation of the array (pixel exposure during the readout of the array). Only two control pulses are needed for all the pixels at the end of exposure which allows high speed exposure control.

  15. A neighbor pixel communication filtering structure for Dynamic Vision Sensors

    NASA Astrophysics Data System (ADS)

    Xu, Yuan; Liu, Shiqi; Lu, Hehui; Zhang, Zilong

    2017-02-01

    For Dynamic Vision Sensors (DVS), thermal noise and junction leakage current induced Background Activity (BA) is the major cause of the deterioration of images quality. Inspired by the smoothing filtering principle of horizontal cells in vertebrate retina, A DVS pixel with Neighbor Pixel Communication (NPC) filtering structure is proposed to solve this issue. The NPC structure is designed to judge the validity of pixel's activity through the communication between its 4 adjacent pixels. The pixel's outputs will be suppressed if its activities are determined not real. The proposed pixel's area is 23.76×24.71μm2 and only 3ns output latency is introduced. In order to validate the effectiveness of the structure, a 5×5 pixel array has been implemented in SMIC 0.13μm CIS process. 3 test cases of array's behavioral model show that the NPC-DVS have an ability of filtering the BA.

  16. Measurement of Lorentz Angle for the CMS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Kumar, Ashish

    2010-02-01

    At the core of the CMS all-silicon tracking system is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution 3D coordinates of the tracks produced in high energy pp collisions. Under the combined action of electric and magnetic fields, the charged carriers traversing the pixel sensors experience the Lorentz force. It causes charge sharing among neighboring pixels which is crucial in enhancing the spatial resolution. In the barrel pixels, the electric and magnetic fields are perpendicular resulting in maximum Lorentz drift, while, in the disks, the fields are oriented at 20 degrees resulting in much smaller Lorentz drift. We present the results of Lorentz angle measurement for the pixel detector using CMS data taken with cosmic runs. )

  17. Staring at Saturn

    NASA Image and Video Library

    2016-09-15

    NASA's Cassini spacecraft stared at Saturn for nearly 44 hours on April 25 to 27, 2016, to obtain this movie showing just over four Saturn days. With Cassini's orbit being moved closer to the planet in preparation for the mission's 2017 finale, scientists took this final opportunity to capture a long movie in which the planet's full disk fit into a single wide-angle camera frame. Visible at top is the giant hexagon-shaped jet stream that surrounds the planet's north pole. Each side of this huge shape is slightly wider than Earth. The resolution of the 250 natural color wide-angle camera frames comprising this movie is 512x512 pixels, rather than the camera's full resolution of 1024x1024 pixels. Cassini's imaging cameras have the ability to take reduced-size images like these in order to decrease the amount of data storage space required for an observation. The spacecraft began acquiring this sequence of images just after it obtained the images to make a three-panel color mosaic. When it began taking images for this movie sequence, Cassini was 1,847,000 miles (2,973,000 kilometers) from Saturn, with an image scale of 355 kilometers per pixel. When it finished gathering the images, the spacecraft had moved 171,000 miles (275,000 kilometers) closer to the planet, with an image scale of 200 miles (322 kilometers) per pixel. A movie is available at http://photojournal.jpl.nasa.gov/catalog/PIA21047

  18. Mars Science Laboratory Engineering Cameras

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  19. Further applications for mosaic pixel FPA technology

    NASA Astrophysics Data System (ADS)

    Liddiard, Kevin C.

    2011-06-01

    In previous papers to this SPIE forum the development of novel technology for next generation PIR security sensors has been described. This technology combines the mosaic pixel FPA concept with low cost optics and purpose-designed readout electronics to provide a higher performance and affordable alternative to current PIR sensor technology, including an imaging capability. Progressive development has resulted in increased performance and transition from conventional microbolometer fabrication to manufacture on 8 or 12 inch CMOS/MEMS fabrication lines. A number of spin-off applications have been identified. In this paper two specific applications are highlighted: high performance imaging IRFPA design and forest fire detection. The former involves optional design for small pixel high performance imaging. The latter involves cheap expendable sensors which can detect approaching fire fronts and send alarms with positional data via mobile phone or satellite link. We also introduce to this SPIE forum the application of microbolometer IR sensor technology to IoT, the Internet of Things.

  20. The Phase1 CMS Pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Tavolaro, V. R.

    2016-12-01

    The pixel detector of the CMS experiment will be replaced in an extended end-of-year shutdown during winter 2016/2017 with an upgraded one able to cope with peak instantaneous luminosities beyond the nominal LHC instantaneous luminosity of 1 × 1034 cm-2 s-1. Under the conditions expected in the coming years, which will see an increase of a factor two in instantaneous luminosity, the present system would experience a dynamic inefficiency caused mainly by data losses due to buffer overflows. The Phase I upgrade of the CMS pixel detector, described in this paper, will operate at full efficiency at an instantaneous luminosity of 2 × 1034 cm-2 s-1 and beyond, thanks to a new readout chip. The new detector will feature one additional tracking point both in the barrel and in the forward regions, while reducing the material budget as a result of a new CO2 cooling system and optimised layout of the services. In this paper, the design and the technological choices of the Phase I detector will be reviewed and the status of the construction of the detector and the performance of its components will be discussed.

  1. Active pixel sensor array with multiresolution readout

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor); Pain, Bedabrata (Inventor)

    1999-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node. There is also a readout circuit, part of which can be disposed at the bottom of each column of cells and be common to all the cells in the column. The imaging device can also include an electronic shutter formed on the substrate adjacent the photogate, and/or a storage section to allow for simultaneous integration. In addition, the imaging device can include a multiresolution imaging circuit to provide images of varying resolution. The multiresolution circuit could also be employed in an array where the photosensitive portion of each pixel cell is a photodiode. This latter embodiment could further be modified to facilitate low light imaging.

  2. Ultra large mode area pixelated Bragg fiber

    NASA Astrophysics Data System (ADS)

    Yehouessi, J.-P.; Bouwmans, G.; Vanvincq, O.; Cassez, A.; Habert, R.; Quiquempois, Y.; Bigot, L.

    2016-03-01

    We report on the design and the fabrication of a new design of an all-solid Bragg fiber based on the pixelization and heterostructuration of a cladding made of only two high index rings. The thickness of the low index ring as well as the geometry of the heterostructuration (its symmetry and the number of removed pixels) have been chosen to maximize the confinement losses of the Higher Order Modes (HOM) (above 10 dB/m) while keeping the Fundamental Mode (FM) losses low (below 0.1 dB/m). The proposed geometry allows having access to different Mode Field Diameter (MFD) from 54 μm to 60 μm at 1 μm wavelength by drawing the same stack to different fiber (and hence, core) diameters. As a result, a record MFD of 60 μm is reported for a Solid Core Photonic Bandgap Fiber (SC-PBGF) and single-mode behavior is obtained experimentally even for a short fiber length (few tens centimeters) maintained straight.

  3. Silicon pixel R&D for CLIC

    NASA Astrophysics Data System (ADS)

    Munker, M.

    2017-01-01

    Challenging detector requirements are imposed by the physics goals at the future multi-TeV e+ e‑ Compact Linear Collider (CLIC). A single point resolution of 3 μm for the vertex detector and 7 μm for the tracker is required. Moreover, the CLIC vertex detector and tracker need to be extremely light weighted with a material budget of 0.2% X0 per layer in the vertex detector and 1–2% X0 in the tracker. A fast time slicing of 10 ns is further required to suppress background from beam-beam interactions. A wide range of sensor and readout ASIC technologies are investigated within the CLIC silicon pixel R&D effort. Various hybrid planar sensor assemblies with a pixel size of 25×25 μm2 and 55×55 μm2 have been produced and characterised by laboratory measurements and during test-beam campaigns. Experimental and simulation results for thin (50 μm–500 μm) slim edge and active-edge planar, and High-Voltage CMOS sensors hybridised to various readout ASICs (Timepix, Timepix3, CLICpix) are presented.

  4. A single pixel camera video ophthalmoscope

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  5. Design and Optimization of Multi-Pixel Transition-Edge Sensors for X-Ray Astronomy Applications

    NASA Technical Reports Server (NTRS)

    Smith, Stephen J.; Adams, Joseph S.; Bandler, Simon R.; Chervenak, James A.; Datesman, Aaron Michael; Eckart, Megan E.; Ewin, Audrey J.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.; hide

    2017-01-01

    Multi-pixel transition-edge sensors (TESs), commonly referred to as 'hydras', are a type of position sensitive micro-calorimeter that enables very large format arrays to be designed without commensurate increase in the number of readout channels and associated wiring. In the hydra design, a single TES is coupled to discrete absorbers via varied thermal links. The links act as low pass thermal filters that are tuned to give a different characteristic pulse shape for x-ray photons absorbed in each of the hydra sub pixels. In this contribution we report on the experimental results from hydras consisting of up to 20 pixels per TES. We discuss the design trade-offs between energy resolution, position discrimination and number of pixels and investigate future design optimizations specifically targeted at meeting the readout technology considered for Lynx.

  6. Multi-scale feature learning on pixels and super-pixels for seminal vesicles MRI segmentation

    NASA Astrophysics Data System (ADS)

    Gao, Qinquan; Asthana, Akshay; Tong, Tong; Rueckert, Daniel; Edwards, Philip "Eddie"

    2014-03-01

    We propose a learning-based approach to segment the seminal vesicles (SV) via random forest classifiers. The proposed discriminative approach relies on the decision forest using high-dimensional multi-scale context-aware spatial, textual and descriptor-based features at both pixel and super-pixel level. After affine transformation to a template space, the relevant high-dimensional multi-scale features are extracted and random forest classifiers are learned based on the masked region of the seminal vesicles from the most similar atlases. Using these classifiers, an intermediate probabilistic segmentation is obtained for the test images. Then, a graph-cut based refinement is applied to this intermediate probabilistic representation of each voxel to get the final segmentation. We apply this approach to segment the seminal vesicles from 30 MRI T2 training images of the prostate, which presents a particularly challenging segmentation task. The results show that the multi-scale approach and the augmentation of the pixel based features with the super-pixel based features enhances the discriminative power of the learnt classifier which leads to a better quality segmentation in some very difficult cases. The results are compared to the radiologist labeled ground truth using leave-one-out cross-validation. Overall, the Dice metric of 0:7249 and Hausdorff surface distance of 7:0803 mm are achieved for this difficult task.

  7. Analysis of pixel circuits in CMOS image sensors

    NASA Astrophysics Data System (ADS)

    Mei, Zou; Chen, Nan; Yao, Li-bin

    2015-04-01

    CMOS image sensors (CIS) have lower power consumption, lower cost and smaller size than CCD image sensors. However, generally CCDs have higher performance than CIS mainly due to lower noise. The pixel circuit used in CIS is the first part of the signal processing circuit and connected to photodiode directly, so its performance will greatly affect the CIS or even the whole imaging system. To achieve high performance, CMOS image sensors need advanced pixel circuits. There are many pixel circuits used in CIS, such as passive pixel sensor (PPS), 3T and 4T active pixel sensor (APS), capacitive transimpedance amplifier (CTIA), and passive pixel sensor (PPS). At first, the main performance parameters of each pixel structure including the noise, injection efficiency, sensitivity, power consumption, and stability of bias voltage are analyzed. Through the theoretical analysis of those pixel circuits, it is concluded that CTIA pixel circuit has good noise performance, high injection efficiency, stable photodiode bias, and high sensitivity with small integrator capacitor. Furthermore, the APS and CTIA pixel circuits are simulated in a standard 0.18-μm CMOS process and using a n-well/p-sub photodiode by SPICE and the simulation result confirms the theoretical analysis result. It shows the possibility that CMOS image sensors can be extended to a wide range of applications requiring high performance.

  8. Pixel response function experimental techniques and analysis of active pixel sensor star cameras

    NASA Astrophysics Data System (ADS)

    Fumo, Patrick; Waldron, Erik; Laine, Juha-Pekka; Evans, Gary

    2015-04-01

    The pixel response function (PRF) of a pixel within a focal plane is defined as the pixel intensity with respect to the position of a point source within the pixel. One of its main applications is in the field of astrometry, which is a branch of astronomy that deals with positioning data of a celestial body for tracking movement or adjusting the attitude of a spacecraft. Complementary metal oxide semiconductor (CMOS) image sensors generally offer better radiation tolerance to protons and heavy ions than CCDs making them ideal candidates for space applications aboard satellites, but like all image sensors they are limited by their spatial frequency response, better known as the modulation transfer function. Having a well-calibrated PRF allows us to eliminate some of the uncertainty in the spatial response of the system providing better resolution and a more accurate centroid estimation. This paper describes the experimental setup for determining the PRF of a CMOS image sensor and analyzes the effect on the oversampled point spread function (PSF) of an image intensifier, as well as the effects due to the wavelength of light used as a point source. It was found that using electron bombarded active pixel sensor (EBAPS) intensification technology had a significant impact on the PRF of the camera being tested as a result of an increase in the amount of carrier diffusion between collection sites generated by the intensification process. Taking the full width at half maximum (FWHM) of the resulting data, it was found that the intensified version of a CMOS camera exhibited a PSF roughly 16.42% larger than its nonintensified counterpart.

  9. Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

    NASA Astrophysics Data System (ADS)

    Maneuski, D.; Bates, R.; Blue, A.; Buttar, C.; Doonan, K.; Eklund, L.; Gimenez, E. N.; Hynds, D.; Kachkanov, S.; Kalliopuska, J.; McMullen, T.; O'Shea, V.; Tartoni, N.; Plackett, R.; Vahanen, S.; Wraight, K.

    2015-03-01

    Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects.

  10. Pixel detectors for x-ray imaging spectroscopy in space

    NASA Astrophysics Data System (ADS)

    Treis, J.; Andritschke, R.; Hartmann, R.; Herrmann, S.; Holl, P.; Lauf, T.; Lechner, P.; Lutz, G.; Meidinger, N.; Porro, M.; Richter, R. H.; Schopper, F.; Soltau, H.; Strüder, L.

    2009-03-01

    Pixelated semiconductor detectors for X-ray imaging spectroscopy are foreseen as key components of the payload of various future space missions exploring the x-ray sky. Located on the platform of the new Spectrum-Roentgen-Gamma satellite, the eROSITA (extended Roentgen Survey with an Imaging Telescope Array) instrument will perform an imaging all-sky survey up to an X-ray energy of 10 keV with unprecedented spectral and angular resolution. The instrument will consist of seven parallel oriented mirror modules each having its own pnCCD camera in the focus. The satellite born X-ray observatory SIMBOL-X will be the first mission to use formation-flying techniques to implement an X-ray telescope with an unprecedented focal length of around 20 m. The detector instrumentation consists of separate high- and low energy detectors, a monolithic 128 × 128 DEPFET macropixel array and a pixellated CdZTe detector respectively, making energy band between 0.5 to 80 keV accessible. A similar concept is proposed for the next generation X-ray observatory IXO. Finally, the MIXS (Mercury Imaging X-ray Spectrometer) instrument on the European Mercury exploration mission BepiColombo will use DEPFET macropixel arrays together with a small X-ray telescope to perform a spatially resolved planetary XRF analysis of Mercury's crust. Here, the mission concepts and their scientific targets are briefly discussed, and the resulting requirements on the detector devices together with the implementation strategies are shown.

  11. Pixel-level robust digital image correlation.

    PubMed

    Cofaru, Corneliu; Philips, Wilfried; Van Paepegem, Wim

    2013-12-02

    Digital Image Correlation (DIC) is a well-established non-contact optical metrology method. It employs digital image analysis to extract the full-field displacements and strains that occur in objects subjected to external stresses. Despite recent DIC progress, many problematic areas which greatly affect accuracy and that can seldomly be avoided, received very little attention. Problems posed by the presence of sharp displacement discontinuities, reflections, object borders or edges can be linked to the analysed object's properties and deformation. Other problematic areas, such as image noise, localized reflections or shadows are related more to the image acquisition process. This paper proposes a new subset-based pixel-level robust DIC method for in-plane displacement measurement which addresses all of these problems in a straightforward and unified approach, significantly improving DIC measurement accuracy compared to classic approaches. The proposed approach minimizes a robust energy functional which adaptively weighs pixel differences in the motion estimation process. The aim is to limit the negative influence of pixels that present erroneous or inconsistent motions by enforcing local motion consistency. The proposed method is compared to the classic Newton-Raphson DIC method in terms of displacement accuracy in three experiments. The first experiment is numerical and presents three combined problems: sharp displacement discontinuities, missing image information and image noise. The second experiment is a real experiment in which a plastic specimen is developing a lateral crack due to the application of uniaxial stress. The region around the crack presents both reflections that saturate the image intensity levels leading to missing image information, as well as sharp motion discontinuities due to the plastic film rupturing. The third experiment compares the proposed and classic DIC approaches with generic computer vision optical flow methods using images from

  12. How big is an OMI pixel?

    NASA Astrophysics Data System (ADS)

    de Graaf, Martin; Sihler, Holger; Tilstra, Lieuwe G.; Stammes, Piet

    2016-08-01

    The Ozone Monitoring Instrument (OMI) is a push-broom imaging spectrometer, observing solar radiation backscattered by the Earth's atmosphere and surface. The incoming radiation is detected using a static imaging CCD (charge-coupled device) detector array with no moving parts, as opposed to most of the previous satellite spectrometers, which used a moving mirror to scan the Earth in the across-track direction. The field of view (FoV) of detector pixels is the solid angle from which radiation is observed, averaged over the integration time of a measurement. The OMI FoV is not quadrangular, which is common for scanning instruments, but rather super-Gaussian shaped and overlapping with the FoV of neighbouring pixels. This has consequences for pixel-area-dependent applications, like cloud fraction products, and visualisation.The shapes and sizes of OMI FoVs were determined pre-flight by theoretical and experimental tests but never verified after launch. In this paper the OMI FoV is characterised using collocated MODerate resolution Imaging Spectroradiometer (MODIS) reflectance measurements. MODIS measurements have a much higher spatial resolution than OMI measurements and spectrally overlap at 469 nm. The OMI FoV was verified by finding the highest correlation between MODIS and OMI reflectances in cloud-free scenes, assuming a 2-D super-Gaussian function with varying size and shape to represent the OMI FoV. Our results show that the OMPIXCOR product 75FoV corner coordinates are accurate as the full width at half maximum (FWHM) of a super-Gaussian FoV model when this function is assumed. The softness of the function edges, modelled by the super-Gaussian exponents, is different in both directions and is view angle dependent.The optimal overlap function between OMI and MODIS reflectances is scene dependent and highly dependent on time differences between overpasses, especially with clouds in the scene. For partially clouded scenes, the optimal overlap function was

  13. Pixel-level plasmonic microcavity infrared photodetector

    NASA Astrophysics Data System (ADS)

    Jing, You Liang; Li, Zhi Feng; Li, Qian; Chen, Xiao Shuang; Chen, Ping Ping; Wang, Han; Li, Meng Yao; Li, Ning; Lu, Wei

    2016-05-01

    Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging.

  14. Pixel-level plasmonic microcavity infrared photodetector

    PubMed Central

    Jing, You Liang; Li, Zhi Feng; Li, Qian; Chen, Xiao Shuang; Chen, Ping Ping; Wang, Han; Li, Meng Yao; Li, Ning; Lu, Wei

    2016-01-01

    Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging. PMID:27181111

  15. Silicon buried channels for pixel detector cooling

    NASA Astrophysics Data System (ADS)

    Boscardin, M.; Conci, P.; Crivellari, M.; Ronchin, S.; Bettarini, S.; Bosi, F.

    2013-08-01

    The support and cooling structures add important contributions to the thickness, in radiation length, of vertex detectors. In order to minimize the material budget of pixel sensors, we developed a new approach to integrate the cooling into the silicon devices. The microchannels are formed in silicon using isotropic SF6 plasma etching in a DRIE (deep reactive ion etcher) equipment. Due to their peculiar profiles, the channels can be sealed by a layer of a PECVD silicon oxide. We have realized on a silicon wafer microchannels with different geometries and hydraulic diameters. We describe the main fabrication steps of microchannels with focus on the channel definition. The experimental results are reported on the thermal characterization of several prototypes, using a mixture of glycol and water as a liquid coolant. The prototypes have shown high cooling efficiency and high-pressure breaking strength.

  16. CMB component separation in the pixel domain

    SciTech Connect

    Doroshkevich, A.; Verkhodanov, O.

    2011-02-15

    We show that the popular internal linear combination approach is unstable with respect to division of the observed map pixels to a set of 'homogeneous' subsamples. For various choices of such subsamples we can obtain a restored CMB signal with amplitudes ranging from zero to the amplitude of the observed signal. We propose an approach which allows us to obtain corrected estimates of the CMB power spectrum C{sub l} at l{<=}30 and provides results similar to WMAP for larger l. Using this approach, we eliminate some anomalies of the WMAP results. In particular, our estimate of the quadrupole is consistent with the theoretically expected one. The effect of the 'axis of evil' is suppressed, and the symmetry of the north and south galactic hemispheres increases. These results can change estimates of quadrupole polarization and the redshift of reionization of the Universe. We also propose a new simple approach which can improve the WMAP estimates of the high l power spectrum.

  17. Operational experience with the ALICE pixel detector

    NASA Astrophysics Data System (ADS)

    Mastroserio, A.

    2017-01-01

    The Silicon Pixel Detector (SPD) constitutes the two innermost layers of the Inner Tracking System of the ALICE experiment and it is the closest detector to the interaction point. As a vertex detector, it has the unique feature of generating a trigger signal that contributes to the L0 trigger of the ALICE experiment. The SPD started collecting data since the very first pp collisions at LHC in 2009 and since then it has taken part in all pp, Pb-Pb and p-Pb data taking campaigns. This contribution will present the main features of the SPD, the detector performance and the operational experience, including calibration and optimization activities from Run 1 to Run 2.

  18. Artificial Structural Color Pixels: A Review

    PubMed Central

    Zhao, Yuqian; Zhao, Yong; Hu, Sheng; Lv, Jiangtao; Ying, Yu; Gervinskas, Gediminas; Si, Guangyuan

    2017-01-01

    Inspired by natural photonic structures (Morpho butterfly, for instance), researchers have demonstrated varying artificial color display devices using different designs. Photonic-crystal/plasmonic color filters have drawn increasing attention most recently. In this review article, we show the developing trend of artificial structural color pixels from photonic crystals to plasmonic nanostructures. Such devices normally utilize the distinctive optical features of photonic/plasmon resonance, resulting in high compatibility with current display and imaging technologies. Moreover, dynamical color filtering devices are highly desirable because tunable optical components are critical for developing new optical platforms which can be integrated or combined with other existing imaging and display techniques. Thus, extensive promising potential applications have been triggered and enabled including more abundant functionalities in integrated optics and nanophotonics. PMID:28805736

  19. Research of IRFPAs' reliability evaluation by bad pixel

    NASA Astrophysics Data System (ADS)

    Hao, Lichao; Huang, Aibo; Lai, Canxiong; Chen, Xing; Hao, Mingming; Chen, Honglei; Lu, Guoguang; Huang, Yun; En, Yunfei

    2015-10-01

    Reliability is an important index to ensure the application of infrared focal plane arrays (IRFPAs) in complex environment, and it becomes a major bottleneck problem of IRFPAs' development. Because of the characteristics such as type, nature, quantity, location and distribution et al, bad pixel which contains initial bad pixel and used bad pixel has outstanding advantage for failure analysis and reliability evaluation of IRFPAs. In this paper, the structure of IRPFAs has been introduced in detail, and the damage mechanisms of used bad pixel also have been analyzed deeply. At the same time, the feasibility to study IRPFAs' damage stress, failure position, damage mechanism has been discussed all around. The research of bad pixel can be used to optimize the structure and process, meanwhile it also can improve the accuracy of bad pixel identification and replacements.

  20. Super pixel-level dictionary learning for hyperspectral image classification

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Zhu, Wen; Liao, Bo; Fu, Xiangzheng

    2017-08-01

    This paper presents a superpixel-level dictionary learning model for hyperspectral data. The idea is to divide the hyperspectral image into a number of super-pixels by means of the super-pixel segmentation method. Each super-pixel is a spatial neighborhood called contextual group. That is, each pixel is represented using a linear combination of a few dictionary items learned from the train data, but since pixels inside a super-pixel are often consisting of the same materials, their linear combinations are constrained to use common items from the dictionary. To this end, the sparse coefficients of the context group have a common sparse pattern by using the joint sparse regularizer for dictionary learning. The sparse coefficients are then used for classification using linear support vector machines. The validity of the proposed method is experimentally verified on a real hyperspectral images.

  1. Electromagnetic modeling of QWIP FPA pixels

    NASA Astrophysics Data System (ADS)

    Choi, K. K.; Jhabvala, M. D.; Forrai, D. P.; Waczynski, A.; Sun, J.; Jones, R.

    2011-06-01

    Rigorous electromagnetic (EM) field modeling is applied to calculate the external quantum efficiency (QE) of various quantum well infrared photodetector (QWIP) pixel geometries with thinned substrates. We found that for a 24 × 24 × 1.5 μm3 cross-grating QWIP, the QE is peaked at 13.0, 11.0, and 8.4 μm, insensitive to the grating periods. These peaks are identified as the first three harmonic resonances associated with the pixel resonant cavity. For a regular prismshaped corrugated QWIP (C-QWIPs) with a 25-μm pitch, the QE oscillates about its classical value of 24.5% within the calculated wavelength range from 3 to 15 μm. A peaked value of 32% occurs at 9.1 μm. For pyramidal C-QWIPs, the maximum QE is 42%, and for cone-shaped C-QWIPs, it is 35%. In the presence of an anti-reflection coating, the oscillation amplitude diminishes, and the average values generally rise to near the peaks of the oscillations. The modeling results are compared with the experimental data for grating QWIP focal plane arrays (FPAs) and prismshaped C-QWIP FPAs; satisfactory agreements were achieved for both. After verifying our EM approach, we explored other detector geometries and found new types of resonator QWIPs (R-QWIPs) that can provide 30% QE at certain wavelengths on a 1.5-μm-thick active material. Combining the high QE of a resonator and the high gain of a thin material layer, the new R-QWIPs will have a conversion efficiency far higher than the existing QWIP detectors. The present resonator approach will also have an impact on other detector technologies.

  2. Fast Pixel Buffer For Processing With Lookup Tables

    NASA Technical Reports Server (NTRS)

    Fisher, Timothy E.

    1992-01-01

    Proposed scheme for buffering data on intensities of picture elements (pixels) of image increases rate or processing beyond that attainable when data read, one pixel at time, from main image memory. Scheme applied in design of specialized image-processing circuitry. Intended to optimize performance of processor in which electronic equivalent of address-lookup table used to address those pixels in main image memory required for processing.

  3. Steganography on quantum pixel images using Shannon entropy

    NASA Astrophysics Data System (ADS)

    Laurel, Carlos Ortega; Dong, Shi-Hai; Cruz-Irisson, M.

    2016-07-01

    This paper presents a steganographical algorithm based on least significant bit (LSB) from the most significant bit information (MSBI) and the equivalence of a bit pixel image to a quantum pixel image, which permits to make the information communicate secretly onto quantum pixel images for its secure transmission through insecure channels. This algorithm offers higher security since it exploits the Shannon entropy for an image.

  4. Mapping Capacitive Coupling Among Pixels in a Sensor Array

    NASA Technical Reports Server (NTRS)

    Seshadri, Suresh; Cole, David M.; Smith, Roger M.

    2010-01-01

    An improved method of mapping the capacitive contribution to cross-talk among pixels in an imaging array of sensors (typically, an imaging photodetector array) has been devised for use in calibrating and/or characterizing such an array. The method involves a sequence of resets of subarrays of pixels to specified voltages and measurement of the voltage responses of neighboring non-reset pixels.

  5. Fast Pixel Buffer For Processing With Lookup Tables

    NASA Technical Reports Server (NTRS)

    Fisher, Timothy E.

    1992-01-01

    Proposed scheme for buffering data on intensities of picture elements (pixels) of image increases rate or processing beyond that attainable when data read, one pixel at time, from main image memory. Scheme applied in design of specialized image-processing circuitry. Intended to optimize performance of processor in which electronic equivalent of address-lookup table used to address those pixels in main image memory required for processing.

  6. CMOS monolithic pixel sensors research and development at LBNL

    NASA Astrophysics Data System (ADS)

    Contarato, D.; Bussat, J.-M.; Denes, P.; Greiner, L.; Kim, T.; Stezelberger, T.; Wieman, H.; Battaglia, M.; Hooberman, B.; Tompkins, L.

    2007-12-01

    This paper summarizes the recent progress in the design and characterization of CMOS pixel sensors at LBNL. Results of lab tests, beam tests and radiation hardness tests carried out at LBNL on a test structure with pixels of various sizes are reported. The first results of the characterization of back-thinned CMOS pixel sensors are also reported, and future plans and activities are discussed.

  7. GaAs QWIP Array Containing More Than a Million Pixels

    NASA Technical Reports Server (NTRS)

    Jhabvala, Murzy; Choi, K. K.; Gunapala, Sarath

    2005-01-01

    A 1,024 x 1,024-pixel array of quantum-well infrared photodetectors (QWIPs) has been built on a 1.8 x 1.8- cm GaAs chip. In tests, the array was found to perform well in detecting images at wavelengths from 8 to 9 m in operation at temperatures between 60 and 70 K. The largest-format QWIP prior array that performed successfully in tests contained 512 x 640 pixels. There is continuing development effort directed toward satisfying actual and anticipated demands to increase numbers of pixels and pixel sizes in order to increase the imaging resolution of infrared photodetector arrays. A 1,024 x 1,024-pixel and even larger formats have been achieved in the InSb and HgCdTe material systems, but photodetector arrays in these material systems are very expensive and manufactured by fewer than half a dozen large companies. In contrast, GaAs-photodetector-array technology is very mature, and photodetectors in the GaAs material system can be readily manufactured by a wide range of industrial technologists, by universities, and government laboratories. There is much similarity between processing in the GaAs industry and processing in the pervasive silicon industry. With respect to yield and cost, the performance of GaAs technology substantially exceeds that of InSb and HgCdTe technologies. In addition, GaAs detectors can be designed to respond to any portion of the wavelength range from 3 to about 16 micrometers - a feature that is very desirable for infrared imaging. GaAs QWIP arrays, like the present one, have potential for use as imaging sensors in infrared measuring instruments, infrared medical imaging systems, and infrared cameras.

  8. Hit efficiency study of CMS prototype forward pixel detectors

    SciTech Connect

    Kim, Dongwook; /Johns Hopkins U.

    2006-01-01

    In this paper the author describes the measurement of the hit efficiency of a prototype pixel device for the CMS forward pixel detector. These pixel detectors were FM type sensors with PSI46V1 chip readout. The data were taken with the 120 GeV proton beam at Fermilab during the period of December 2004 to February 2005. The detectors proved to be highly efficient (99.27 {+-} 0.02%). The inefficiency was primarily located near the corners of the individual pixels.

  9. Dead pixel correction techniques for dual-band infrared imagery

    NASA Astrophysics Data System (ADS)

    Nguyen, Chuong T.; Mould, Nick; Regens, James L.

    2015-07-01

    We present two new dead pixel correction algorithms for dual-band infrared imagery. Specifically, we address the problem of repairing unresponsive elements in the sensor array using signal processing techniques to overcome deficiencies in image quality that are present following the nonuniformity correction process. Traditionally, dead pixel correction has been performed almost exclusively using variations of the nearest neighbor technique, where the value of the dead pixel is estimated based on pixel values associated with the neighboring image structure. Our approach differs from existing techniques, for the first time we estimate the values of dead pixels using information from both thermal bands collaboratively. The proposed dual-band statistical lookup (DSL) and dual-band inpainting (DIP) algorithms use intensity and local gradient information to estimate the values of dead pixels based on the values of unaffected pixels in the supplementary infrared band. The DSL algorithm is a regression technique that uses the image intensities from the reference band to estimate the dead pixel values in the band undergoing correction. The DIP algorithm is an energy minimization technique that uses the local image gradient from the reference band and the boundary values from the affected band to estimate the dead pixel values. We evaluate the effectiveness of the proposed algorithms with 50 dual-band videos. Simulation results indicate that the proposed techniques achieve perceptually and quantitatively superior results compared to existing methods.

  10. A GPU based real-time image processing for an axis-symmetrical optical laser triangulation system

    NASA Astrophysics Data System (ADS)

    Buschinelli, Pedro D. V.; Landeira, Gabriel A. B.; Kohler, Christian; Albertazzi, Armando; Teixeira da Silva, Guilherme B.

    2012-10-01

    An axis-symmetrical optical laser triangulation system was developed by the authors to measure the inner geometry of long pipes used in the oil industry. It has a special optical configuration able to acquire shape information of the inner geometry of a section of a pipe from a single image frame. It uses a radial light sheet and conical triangulation to measure the inner geometry of pipes in cylindrical coordinates. A set of equally spaced images of 1024 x 1024 pixels is acquired at 50 Hz while the device is moved along the pipe's axis. The measured geometry is analyzed to identify defects like corrosion damage. A GPU based processing algorithm has been developed to make the system able to process these images and display the geometrical/measurement result in real-time. The algorithm implements an adaptive threshold filter and a light intensity peak search using a graphic processing unit programming architecture (CUDA). Prior to the parallel algorithms (called kernels) a texture data type is used to remap the image, converting from polar to Cartesian coordinates, mapping angular and radial values in a 2D pixel data matrix. Radial lines are only scanned in a limited range (256 pixels) between a minimum and a maximum radius value. The achieved image processing frequency is about 470 frames per second (FPS) using a notebook equipped with a GTX 285m graphics card.

  11. Synchrotron radiation microtomography of lung specimens

    NASA Astrophysics Data System (ADS)

    Shimizu, Kenji; Ikezoe, Junpei; Ikura, Hirohiko; Ebara, Hidemi; Nagareda, Tomofumi; Yagi, Naoto; Umetani, Keiji; Uesugi, Kentaro; Okada, Kyoko; Sugita, Atsuro; Tanaka, Minoru

    2000-04-01

    We have applied a synchrotron radiation computed tomography (SRCT) system to the lung specimens and evaluated its resolving power compared with the histopathologic appearances, precisely. An SRCT system has been constructed in the bending magnet beamline at the SPring-8. The system consists of a double-crystal monochromator, a rotating sample stage, a fluorescent screen, and a charge-coupled device (CCD) array detector (1024 X 1024 pixels with 12 X 12 micrometers 2 pixel size). The energy of the x-ray beam was tuned to 9 - 12 keV. The lungs obtained at autopsy were inflated and fixed by Heitzman's method. A cylindrical specimen (diameter, approximately 8 mm; height, 15 - 25 mm) was rotated in the plane parallel to the beam. The detected signal was transferred to a workstation; then, SRCT images (matrix size, 800 X 800 pixels) were reconstructed by a filtered back- projection. Finally, 6 - 12 micrometer-thick microscopic sections were obtained and stained with hematoxylin and eosin for histopathologic examination. SRCT images well depicted the terminal bronchiole, respiratory bronchiole, alveolar duct, alveolar sac, and alveolar septum. Different pathologic processes (alveolar hemorrhage, alveolitis) demonstrated on SRCT images were well correlated with the histopathologic appearances.

  12. Ultra-high speed burst-mode imager for multi-frame radiography

    SciTech Connect

    Kwiatkowski, Kris; Nedrow, Paul; Mariam, Fesseha; Merrill, Frank E; Morris, Chris L; Saunders, Abdy; Hogan, Gary; Douance, Vincent; Bal, Yibin; Joshi, Atul; Auyeung, John

    2010-01-01

    A 720 x 720 pixel hybrid-CMOS imager was fabricated by Rockwell Scientific (now Teledyne Imaging Sensors). Several cameras have been in operation for 5 years, in a variety of static and dynamic experiments, at the 800MeV proton radiography (pRAD) facility at the LANSCE accelerator. The cameras can operate with a per-pulse adjustable inter-frame time of 250ns to 2s, and with an exposure/integration-time as short as 150 ns. Given the 800 ms total readout time, the imager can be externally synchronized to 0.1-to-5Hz, 50-ns wide proton beam pulses, and record 1000-frame radiographic movies of 5-to-30 minute duration. The effectiveness and dependence of the global electronic shutter on the pixelated Si photo-sensor bias voltage is discussed. The spatial resolution dependence of the full imaging system on various monolithic and structured scintillators is presented. We also present features of a new-generation 10-frame, 1024 x 1024 pixel, 50-ns exposure, 12-bit dynamic range imager, which is now in the design phase.

  13. Evaluation of a single-pixel one-transistor active pixel sensor for fingerprint imaging

    NASA Astrophysics Data System (ADS)

    Xu, Man; Ou, Hai; Chen, Jun; Wang, Kai

    2015-08-01

    Since it first appeared in iPhone 5S in 2013, fingerprint identification (ID) has rapidly gained popularity among consumers. Current fingerprint-enabled smartphones unanimously consists of a discrete sensor to perform fingerprint ID. This architecture not only incurs higher material and manufacturing cost, but also provides only static identification and limited authentication. Hence as the demand for a thinner, lighter, and more secure handset grows, we propose a novel pixel architecture that is a photosensitive device embedded in a display pixel and detects the reflected light from the finger touch for high resolution, high fidelity and dynamic biometrics. To this purpose, an amorphous silicon (a-Si:H) dual-gate photo TFT working in both fingerprint-imaging mode and display-driving mode will be developed.

  14. Separation of metadata and pixel data to speed DICOM tag morphing.

    PubMed

    Ismail, Mahmoud; Philbin, James

    2013-01-01

    The DICOM information model combines pixel data and metadata in single DICOM object. It is not possible to access the metadata separately from the pixel data. There are use cases where only metadata is accessed. The current DICOM object format increases the running time of those use cases. Tag morphing is one of those use cases. Tag morphing includes deletion, insertion or manipulation of one or more of the metadata attributes. It is typically used for order reconciliation on study acquisition or to localize the issuer of patient ID (IPID) and the patient ID attributes when data from one domain is transferred to a different domain. In this work, we propose using Multi-Series DICOM (MSD) objects, which separate metadata from pixel data and remove duplicate attributes, to reduce the time required for Tag Morphing. The time required to update a set of study attributes in each format is compared. The results show that the MSD format significantly reduces the time required for tag morphing.

  15. Firmware development and testing of the ATLAS Pixel Detector / IBL ROD card

    NASA Astrophysics Data System (ADS)

    Gabrielli, A.; Backhaus, M.; Balbi, G.; Bindi, M.; Chen, S. P.; Falchieri, D.; Flick, T.; Hauck, S.; Hsu, S. C.; Kretz, M.; Kugel, A.; Lama, L.; Travaglini, R.; Wensing, M.

    2015-03-01

    The ATLAS Experiment is reworking and upgrading systems during the current LHC shut down. In particular, the Pixel detector has inserted an additional inner layer called the Insertable B-Layer (IBL). The Readout-Driver card (ROD), the Back-of-Crate card (BOC), and the S-Link together form the essential frontend data path of the IBL's off-detector DAQ system. The strategy for IBL ROD firmware development was three-fold: keeping as much of the Pixel ROD datapath firmware logic as possible, employing a complete new scheme of steering and calibration firmware, and designing the overall system to prepare for a future unified code version integrating IBL and Pixel layers. Essential features such as data formatting, frontend-specific error handling, and calibration are added to the ROD data path. An IBL DAQ test bench using a realistic front-end chip model was created to serve as an initial framework for full offline electronic system simulation. In this document, major firmware achievements concerning the IBL ROD data path implementation, test on the test bench and ROD prototypes, will be reported. Recent Pixel collaboration efforts focus on finalizing hardware and firmware tests for the IBL. The plan is to approach a complete IBL DAQ hardware-software installation by the end of 2014.

  16. Analysis of low-offset CTIA amplifier for small-size-pixel infrared focal plane array

    NASA Astrophysics Data System (ADS)

    Zhang, Xue; Huang, Zhangcheng; Shao, Xiumei

    2014-11-01

    The design of input stage amplifier becomes more and more difficult as the expansion of format arrays and reduction of pixel size. A design method of low-offset amplifier based on 0.18-μm process used in small-size pixel is analyzed in order to decrease the dark signal of extended wavelength InGaAs infrared focal plane arrays (IRFPA). Based on an example of a cascode operational amplifier (op-amp), the relationship between input offset voltage and size of each transistor is discussed through theoretical analysis and Monte Carlo simulation. The results indicate that input transistors and load transistors have great influence on the input offset voltage while common-gate transistors are negligible. Furthermore, the offset voltage begins to increase slightly when the width and length of transistors decrease along with the diminution of pixel size, and raises rapidly when the size is smaller than a proximate threshold value. The offset voltage of preamplifiers with differential architecture and single-shared architecture in small pitch pixel are studied. After optimization under same conditions, simulation results show that single-shared architecture has smaller offset voltage than differential architecture.

  17. Design and characterization of high precision in-pixel discriminators for rolling shutter CMOS pixel sensors with full CMOS capability

    NASA Astrophysics Data System (ADS)

    Fu, Y.; Hu-Guo, C.; Dorokhov, A.; Pham, H.; Hu, Y.

    2013-07-01

    In order to exploit the ability to integrate a charge collecting electrode with analog and digital processing circuitry down to the pixel level, a new type of CMOS pixel sensors with full CMOS capability is presented in this paper. The pixel array is read out based on a column-parallel read-out architecture, where each pixel incorporates a diode, a preamplifier with a double sampling circuitry and a discriminator to completely eliminate analog read-out bottlenecks. The sensor featuring a pixel array of 8 rows and 32 columns with a pixel pitch of 80 μm×16 μm was fabricated in a 0.18 μm CMOS process. The behavior of each pixel-level discriminator isolated from the diode and the preamplifier was studied. The experimental results indicate that all in-pixel discriminators which are fully operational can provide significant improvements in the read-out speed and the power consumption of CMOS pixel sensors.

  18. Pixel Stability in HST Advanced Camera for Surveys Images

    NASA Astrophysics Data System (ADS)

    Borncamp, David; Grogin, Norman A.; Bourque, Matthew; Ogaz, Sara

    2017-06-01

    Excess thermal energy present in a Charged Coupled Device (CCD) can result in additional electrical current that is propagated into individual pixels in an exposure. This excess signal from the CCD itself can be persistently existent through multiple exposures and can have an adverse effect on the detectors science performance unless properly flagged and corrected for. The traditional way to correct for this extra charge is to take occasional long-exposure images with the camera shutter closed to map the location of these pixels. These images, generally referred to as “dark” images, allow for the measurement of the thermal-electron contamination present in each pixel of the CCD lattice. This "dark current" can then be subtracted from the science images by re-scaling the dark to the science exposure times. Pixels that have signal above a certain threshold are traditionally marked as “hot” and flagged in the data quality array. Many users will discard these pixels as being bad because of this extra current. However, these pixels may not be "bad" in the traditional sense that they cannot be reliably dark-subtracted. If these pixels are shown to be stable over an anneal period, the charge can be properly subtracted and the extra Poisson noise from this hot pixel’s dark current can be taken into account. Here we present the results of a pixel history study that analyzes every individual pixel of the Hubble Space Telescope's (HST) Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) CCDs over time and allows pixels that were previously marked as bad to be brought back into the science image as a reliable pixel.

  19. High-dynamic-range pixel architectures for diagnostic medical imaging

    NASA Astrophysics Data System (ADS)

    Karim, Karim S.; Yin, Sherman; Nathan, Arokia; Rowlands, John A.

    2004-05-01

    One approach to increase pixel signal-to-noise ratio (SNR) in low noise digital fluoroscopy is to employ in-situ pixel amplification via current-mediated active pixel sensors (C-APS). Experiments reveal a reduction in readout noise and indicate that an a-Si C-APS, coupled together with an established X-ray detection technology such as amorphous selenium (a-Se), can meet the stringent requirements (of < 1000 noise electrons) for digital X-ray fluoroscopy. A challenge with the C-APS circuit is the presence of a small-signal input linearity constraint. While using such a pixel amplifier for real-time fluoroscopy (where the exposure level is small) is feasible, the voltage change at the amplifier input is much higher in chest radiography or mammography due to the larger X-ray exposure levels. The larger input voltage causes the C-APS output to be non-linear thus reducing the pixel dynamic range. In addition, the resulting larger pixel output current causes the external column amplifier to saturate further reducing the pixel dynamic range. In this research, we investigate two alternate amplified pixel architectures that exhibit higher dynamic range. The test pixels are designed and simulated using an a-Si TFT model implemented in Verilog-A and results indicate a linear performance, high dynamic range, and a programmable circuit gain via choice of supply voltage and sampling time. These high dynamic range pixel architectures have the potential to enable a large area, active matrix flat panel imager (AMFPI) to switch instantly between low exposure, fluoroscopic imaging and higher exposure radiographic imaging modes. Lastly, the high dynamic range pixel circuits are suitable for integration with on-panel multiplexers for both gate and data lines, which can further reduce circuit complexity.

  20. Novel integrated CMOS pixel structures for vertex detectors

    SciTech Connect

    Kleinfelder, Stuart; Bieser, Fred; Chen, Yandong; Gareus, Robin; Matis, Howard S.; Oldenburg, Markus; Retiere, Fabrice; Ritter, Hans Georg; Wieman, Howard H.; Yamamoto, Eugene

    2003-10-29

    Novel CMOS active pixel structures for vertex detector applications have been designed and tested. The overriding goal of this work is to increase the signal to noise ratio of the sensors and readout circuits. A large-area native epitaxial silicon photogate was designed with the aim of increasing the charge collected per struck pixel and to reduce charge diffusion to neighboring pixels. The photogate then transfers the charge to a low capacitance readout node to maintain a high charge to voltage conversion gain. Two techniques for noise reduction are also presented. The first is a per-pixel kT/C noise reduction circuit that produces results similar to traditional correlated double sampling (CDS). It has the advantage of requiring only one read, as compared to two for CDS, and no external storage or subtraction is needed. The technique reduced input-referred temporal noise by a factor of 2.5, to 12.8 e{sup -}. Finally, a column-level active reset technique is explored that suppresses kT/C noise during pixel reset. In tests, noise was reduced by a factor of 7.6 times, to an estimated 5.1 e{sup -} input-referred noise. The technique also dramatically reduces fixed pattern (pedestal) noise, by up to a factor of 21 in our tests. The latter feature may possibly reduce pixel-by-pixel pedestal differences to levels low enough to permit sparse data scan without per-pixel offset corrections.

  1. Method for hyperspectral imagery exploitation and pixel spectral unmixing

    NASA Technical Reports Server (NTRS)

    Lin, Ching-Fang (Inventor)

    2003-01-01

    An efficiently hybrid approach to exploit hyperspectral imagery and unmix spectral pixels. This hybrid approach uses a genetic algorithm to solve the abundance vector for the first pixel of a hyperspectral image cube. This abundance vector is used as initial state in a robust filter to derive the abundance estimate for the next pixel. By using Kalman filter, the abundance estimate for a pixel can be obtained in one iteration procedure which is much fast than genetic algorithm. The output of the robust filter is fed to genetic algorithm again to derive accurate abundance estimate for the current pixel. The using of robust filter solution as starting point of the genetic algorithm speeds up the evolution of the genetic algorithm. After obtaining the accurate abundance estimate, the procedure goes to next pixel, and uses the output of genetic algorithm as the previous state estimate to derive abundance estimate for this pixel using robust filter. And again use the genetic algorithm to derive accurate abundance estimate efficiently based on the robust filter solution. This iteration continues until pixels in a hyperspectral image cube end.

  2. CMOS Active-Pixel Image Sensor With Simple Floating Gates

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

    1996-01-01

    Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

  3. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  4. Estimation of proportions in mixed pixels through their region characterization

    NASA Technical Reports Server (NTRS)

    Chittineni, C. B. (Principal Investigator)

    1981-01-01

    A region of mixed pixels can be characterized through the probability density function of proportions of classes in the pixels. Using information from the spectral vectors of a given set of pixels from the mixed pixel region, expressions are developed for obtaining the maximum likelihood estimates of the parameters of probability density functions of proportions. The proportions of classes in the mixed pixels can then be estimated. If the mixed pixels contain objects of two classes, the computation can be reduced by transforming the spectral vectors using a transformation matrix that simultaneously diagonalizes the covariance matrices of the two classes. If the proportions of the classes of a set of mixed pixels from the region are given, then expressions are developed for obtaining the estmates of the parameters of the probability density function of the proportions of mixed pixels. Development of these expressions is based on the criterion of the minimum sum of squares of errors. Experimental results from the processing of remotely sensed agricultural multispectral imagery data are presented.

  5. CMOS Active-Pixel Image Sensor With Simple Floating Gates

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

    1996-01-01

    Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

  6. Mobile NMR: Measuring Pixels, Images, and Spectra

    NASA Astrophysics Data System (ADS)

    Bluemich, Bernhard

    2007-03-01

    The vision of bringing nuclear magnetic resonance out of the lab to the doctor's office, the chemical reactor, or the manufacturing site is becoming reality with the development of mobile NMR. Pioneered for well logging in the oil industry, the concept has been explored for materials testing in a more systematic way since the introduction of the NMR-MOUSE. This is a small, one-sided access NMR sensor which acquires the information of one pixel from a particular spot of a large object. As the sensor explores the stray-fields of a permanent magnet and an rf coil, the magnetic fields are inhomogeneous and the sensitive volume is limited to the region, where both fields are orthogonal and the Larmor frequency lies within the excitation bandwidth. By shaping the magnet and the coil geometries, the shape of the sensitive volume can be tailored to a thin slice or a larger volume a certain distance away from the sensor surface. In the first case, there is a strong field gradient in the depth direction, and in the second case, a homogeneous sweet spot of the field profile is desired. The first case is suitable for measuring high-resolution depth profiles, while the second case is suitable for chemical shift resolved spectroscopy and volume imaging. The basic concepts of open and closed mobile NMR sensors will be discussed along with applications from testing polymer products, cultural heritage, medical tissue, and rock cores.

  7. Singlet mega-pixel resolution lens

    NASA Astrophysics Data System (ADS)

    Lin, Chen-Hung; Lin, Hoang Yan; Chang, Horng

    2008-03-01

    There always exist some new challenges for lens designers to keep their old-line technology update. To minimize lens volume is one of the most notified examples. In this paper we designed a single thick lens, constructed by using one oblique (reflective) surface, apart from two conventional refractive surfaces, to bend the optical path of the optical system to achieve this goal. Detail design procedure, including system layout and lens performance diagrams, will be presented. Following the first order layout, we applied aspherical form to the two refractive surfaces in order to correct the spherical aberration up to an acceptable condition. Then, the reduced aberrations such as coma, astigmatism, field curvature and distortion can easily be corrected with some calculations related to spherical aberration as shown in the publication of H. H. Hopkins (1950). Plastic material is used in the design, because the aspherical surfaces can then be manufactured in a more cost effective way. The final specification of the design is: EFL is 4.6 mm, the F number is 2.8, the over all thickness of lens is 3.6 mm, its MTF is 0.3 at 227 lp/mm in center field and chief ray angle is less than 15 degrees. Lens data as well as optical performance curves are also presented in the paper. In conclusion we have successfully finished a mega-pixel resolution lens design and its overall thickness is compatible with the state of the art.

  8. Hyperspectral Anomaly Detection by Graph Pixel Selection.

    PubMed

    Yuan, Yuan; Ma, Dandan; Wang, Qi

    2016-12-01

    Hyperspectral anomaly detection (AD) is an important problem in remote sensing field. It can make full use of the spectral differences to discover certain potential interesting regions without any target priors. Traditional Mahalanobis-distance-based anomaly detectors assume the background spectrum distribution conforms to a Gaussian distribution. However, this and other similar distributions may not be satisfied for the real hyperspectral images. Moreover, the background statistics are susceptible to contamination of anomaly targets which will lead to a high false-positive rate. To address these intrinsic problems, this paper proposes a novel AD method based on the graph theory. We first construct a vertex- and edge-weighted graph and then utilize a pixel selection process to locate the anomaly targets. Two contributions are claimed in this paper: 1) no background distributions are required which makes the method more adaptive and 2) both the vertex and edge weights are considered which enables a more accurate detection performance and better robustness to noise. Intensive experiments on the simulated and real hyperspectral images demonstrate that the proposed method outperforms other benchmark competitors. In addition, the robustness of the proposed method has been validated by using various window sizes. This experimental result also demonstrates the valuable characteristic of less computational complexity and less parameter tuning for real applications.

  9. Detector apparatus having a hybrid pixel-waveform readout system

    DOEpatents

    Meng, Ling-Jian

    2014-10-21

    A gamma ray detector apparatus comprises a solid state detector that includes a plurality of anode pixels and at least one cathode. The solid state detector is configured for receiving gamma rays during an interaction and inducing a signal in an anode pixel and in a cathode. An anode pixel readout circuit is coupled to the plurality of anode pixels and is configured to read out and process the induced signal in the anode pixel and provide triggering and addressing information. A waveform sampling circuit is coupled to the at least one cathode and configured to read out and process the induced signal in the cathode and determine energy of the interaction, timing of the interaction, and depth of interaction.

  10. Status of the CMS Phase I pixel detector upgrade

    NASA Astrophysics Data System (ADS)

    Spannagel, S.

    2016-09-01

    A new pixel detector for the CMS experiment is being built, owing to the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking while featuring a significantly reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and comprises a low-threshold comparator. These improvements allow the new pixel detector to sustain and improve the efficiency of the current pixel tracker at the increased requirements imposed by high luminosities and pile-up. This contribution gives an overview of the design of the upgraded pixel detector and the status of the upgrade project, and presents test beam performance measurements of the production read-out chip.

  11. Research on ionospheric tomography based on variable pixel height

    NASA Astrophysics Data System (ADS)

    Zheng, Dunyong; Li, Peiqing; He, Jie; Hu, Wusheng; Li, Chaokui

    2016-05-01

    A novel ionospheric tomography technique based on variable pixel height was developed for the tomographic reconstruction of the ionospheric electron density distribution. The method considers the height of each pixel as an unknown variable, which is retrieved during the inversion process together with the electron density values. In contrast to conventional computerized ionospheric tomography (CIT), which parameterizes the model with a fixed pixel height, the variable-pixel-height computerized ionospheric tomography (VHCIT) model applies a disturbance to the height of each pixel. In comparison with conventional CIT models, the VHCIT technique achieved superior results in a numerical simulation. A careful validation of the reliability and superiority of VHCIT was performed. According to the results of the statistical analysis of the average root mean square errors, the proposed model offers an improvement by 15% compared with conventional CIT models.

  12. Single photon counting pixel detectors for synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

    Toyokawa, H.; Broennimann, Ch.; Eikenberry, E. F.; Henrich, B.; Kawase, M.; Kobas, M.; Kraft, P.; Sato, M.; Schmitt, B.; Suzuki, M.; Tanida, H.; Uruga, T.

    2010-11-01

    At the Paul Scherrer Institute PSI an X-ray single photon counting pixel detector (PILATUS) based on the hybrid-pixel detector technology was developed in collaboration with SPring-8. The detection element is a 320 or 450 μm thick silicon sensor forming pixelated pn-diodes with a pitch of 172 μm×172 μm. An array of 2×8 custom CMOS readout chips are indium bump-bonded to the sensor, which leads to 33.5 mm×83.8 mm detective area. Each pixel contains a charge-sensitive amplifier, a single level discriminator and a 20 bit counter. This design realizes a high dynamic range, short readout time of less than 3 ms, a high framing rate of over 200 images per second and an excellent point-spread function. The maximum counting rate achieves more than 2×106 X-rays/s/pixel.

  13. Attenuating Stereo Pixel-Locking via Affine Window Adaptation

    NASA Technical Reports Server (NTRS)

    Stein, Andrew N.; Huertas, Andres; Matthies, Larry H.

    2006-01-01

    For real-time stereo vision systems, the standard method for estimating sub-pixel stereo disparity given an initial integer disparity map involves fitting parabolas to a matching cost function aggregated over rectangular windows. This results in a phenomenon known as 'pixel-locking,' which produces artificially-peaked histograms of sub-pixel disparity. These peaks correspond to the introduction of erroneous ripples or waves in the 3D reconstruction of truly Rat surfaces. Since stereo vision is a common input modality for autonomous vehicles, these inaccuracies can pose a problem for safe, reliable navigation. This paper proposes a new method for sub-pixel stereo disparity estimation, based on ideas from Lucas-Kanade tracking and optical flow, which substantially reduces the pixel-locking effect. In addition, it has the ability to correct much larger initial disparity errors than previous approaches and is more general as it applies not only to the ground plane.

  14. Readout of TPC Tracking Chambers with GEMs and Pixel Chip

    SciTech Connect

    Kadyk, John; Kim, T.; Freytsis, M.; Button-Shafer, J.; Kadyk, J.; Vahsen, S.E.; Wenzel, W.A.

    2007-12-21

    Two layers of GEMs and the ATLAS Pixel Chip, FEI3, have been combined and tested as a prototype for Time Projection Chamber (TPC) readout at the International Linear Collider (ILC). The double-layer GEM system amplifies charge with gain sufficient to detect all track ionization. The suitability of three gas mixtures for this application was investigated, and gain measurements are presented. A large sample of cosmic ray tracks was reconstructed in 3D by using the simultaneous timing and 2D spatial information from the pixel chip. The chip provides pixel charge measurement as well as timing. These results demonstrate that a double GEM and pixel combination, with a suitably modified pixel ASIC, could meet the stringent readout requirements of the ILC.

  15. Using an Active Pixel Sensor In A Vertex Detector

    SciTech Connect

    Matis, Howard S.; Bieser, Fred; Chen, Yandong; Gareus, Robin; Kleinfelder, Stuart; Oldenburg, Markus; Retiere, Fabrice; Ritter, HansGeorg; Wieman, Howard H.; Wurzel, Samuel E.; Yamamoto, Eugene

    2004-04-22

    Research has shown that Active Pixel CMOS sensors can detect charged particles. We have been studying whether this process can be used in a collider environment. In particular, we studied the effect of radiation with 55 MeV protons. These results show that a fluence of about 2 x 10{sup 12} protons/cm{sup 2} reduces the signal by a factor of two while the noise increases by 25%. A measurement 6 months after exposure shows that the silicon lattice naturally repairs itself. Heating the silicon to 100 C reduced the shot noise and increased the collected charge. CMOS sensors have a reduced signal to noise ratio per pixel because charge diffuses to neighboring pixels. We have constructed a photogate to see if this structure can collect more charge per pixel. Results show that a photogate does collect charge in fewer pixels, but it takes about 15 ms to collect all of the electrons produced by a pulse of light.

  16. Attenuating Stereo Pixel-Locking via Affine Window Adaptation

    NASA Technical Reports Server (NTRS)

    Stein, Andrew N.; Huertas, Andres; Matthies, Larry H.

    2006-01-01

    For real-time stereo vision systems, the standard method for estimating sub-pixel stereo disparity given an initial integer disparity map involves fitting parabolas to a matching cost function aggregated over rectangular windows. This results in a phenomenon known as 'pixel-locking,' which produces artificially-peaked histograms of sub-pixel disparity. These peaks correspond to the introduction of erroneous ripples or waves in the 3D reconstruction of truly Rat surfaces. Since stereo vision is a common input modality for autonomous vehicles, these inaccuracies can pose a problem for safe, reliable navigation. This paper proposes a new method for sub-pixel stereo disparity estimation, based on ideas from Lucas-Kanade tracking and optical flow, which substantially reduces the pixel-locking effect. In addition, it has the ability to correct much larger initial disparity errors than previous approaches and is more general as it applies not only to the ground plane.

  17. Progressive band processing of fast iterative pixel purity index

    NASA Astrophysics Data System (ADS)

    Li, Yao; Chang, Chein-I.

    2016-05-01

    Fast Iterative Pixel Purity Index (FIPPI) was previously developed to address two major issues arising in PPI which are the use of skewers whose number must be determined by a priori and inconsistent final results which cannot be reproduced. Recently, a new concept has been developed for hyperspectral data communication according to Band SeQuential (BSQ) acquisition format in such a way that bands can be collected band by band. By virtue of BSQ users are able to develop Progressive Band Processing (PBP) for hyperspectral imaging algorithms so that data analysts can observe progressive profiles of inter-band changes among bands. Its advantages have been justified in several applications, anomaly detection, constrained energy minimization, automatic target generation process, orthogonal subspace projection, PPI, etc. This paper further extends PBP to FIPPI. The idea to implement PBP-FIPPI is to use two loops specified by skewers and bands to process FIPPI. Depending upon which one is implemented in the outer loop two different versions of PBP-FIPPI can be designed. When the outer loop is iterated band by band, it is called to be called Progressive Band Processing of FIPPI (PBP-FIPPI). When the outer loop is iterated by growing skewers, it is called Progressive Skewer Processing of FIPPI (PSP-FIPPI). Interestingly, both versions provide different insights into the design of FIPPI but produce close results.

  18. High performance uncooled amorphous silicon VGA IRFPA with 17-µm pixel-pitch

    NASA Astrophysics Data System (ADS)

    Tissot, J. L.; Durand, A.; Garret, Th.; Minassian, C.; Robert, P.; Tinnes, S.; Vilain, M.

    2010-04-01

    The high level of accumulated expertise by ULIS and CEA/LETI on uncooled microbolometers made from amorphous silicon enables ULIS to develop VGA IRFPA formats with 17μm pixel-pitch to build up the currently available product catalog. This detector keeps all the innovations developed on the 25 μm pixel-pitch ROIC (detector configuration by serial link, low power consumption and wide electrical dynamic range). The specific appeal of this unit lies in the high spatial resolution it provides. The reduction of the pixel-pitch turns this TEC-less VGA array into a product well adapted for high resolution and compact systems. In the last part of the paper, we will look more closely at the high electro-optical performances of this IRFPA and the rapid performance enhancement. We will insist on NETD trade-off with wide thermal dynamic range, as well as the high characteristics uniformity, achieved thanks to the mastering of the amorphous silicon technology coupled with the ROIC design. This technology node paves the way to high end products as well as low end compact smaller formats like 160 x 120 or smaller.

  19. Analysis of Multipath Pixels in SAR Images

    NASA Astrophysics Data System (ADS)

    Zhao, J. W.; Wu, J. C.; Ding, X. L.; Zhang, L.; Hu, F. M.

    2016-06-01

    As the received radar signal is the sum of signal contributions overlaid in one single pixel regardless of the travel path, the multipath effect should be seriously tackled as the multiple bounce returns are added to direct scatter echoes which leads to ghost scatters. Most of the existing solution towards the multipath is to recover the signal propagation path. To facilitate the signal propagation simulation process, plenty of aspects such as sensor parameters, the geometry of the objects (shape, location, orientation, mutual position between adjacent buildings) and the physical parameters of the surface (roughness, correlation length, permittivity)which determine the strength of radar signal backscattered to the SAR sensor should be given in previous. However, it's not practical to obtain the highly detailed object model in unfamiliar area by field survey as it's a laborious work and time-consuming. In this paper, SAR imaging simulation based on RaySAR is conducted at first aiming at basic understanding of multipath effects and for further comparison. Besides of the pre-imaging simulation, the product of the after-imaging, which refers to radar images is also taken into consideration. Both Cosmo-SkyMed ascending and descending SAR images of Lupu Bridge in Shanghai are used for the experiment. As a result, the reflectivity map and signal distribution map of different bounce level are simulated and validated by 3D real model. The statistic indexes such as the phase stability, mean amplitude, amplitude dispersion, coherence and mean-sigma ratio in case of layover are analyzed with combination of the RaySAR output.

  20. Deep-UV-sensitive high-frame-rate backside-illuminated CCD camera developments

    NASA Astrophysics Data System (ADS)

    Dawson, Robin M.; Andreas, Robert; Andrews, James T.; Bhaskaran, Mahalingham; Farkas, Robert; Furst, David; Gershstein, Sergey; Grygon, Mark S.; Levine, Peter A.; Meray, Grazyna M.; O'Neal, Michael; Perna, Steve N.; Proefrock, Donald; Reale, Michael; Soydan, Ramazan; Sudol, Thomas M.; Swain, Pradyumna K.; Tower, John R.; Zanzucchi, Pete

    2002-04-01

    New applications for ultra-violet imaging are emerging in the fields of drug discovery and industrial inspection. High throughput is critical for these applications where millions of drug combinations are analyzed in secondary screenings or high rate inspection of small feature sizes over large areas is required. Sarnoff demonstrated in1990 a back illuminated, 1024 X 1024, 18 um pixel, split-frame-transfer device running at > 150 frames per second with high sensitivity in the visible spectrum. Sarnoff designed, fabricated and delivered cameras based on these CCDs and is now extending this technology to devices with higher pixel counts and higher frame rates through CCD architectural enhancements. The high sensitivities obtained in the visible spectrum are being pushed into the deep UV to support these new medical and industrial inspection applications. Sarnoff has achieved measured quantum efficiencies > 55% at 193 nm, rising to 65% at 300 nm, and remaining almost constant out to 750 nm. Optimization of the sensitivity is being pursued to tailor the quantum efficiency for particular wavelengths. Characteristics of these high frame rate CCDs and cameras will be described and results will be presented demonstrating high UV sensitivity down to 150 nm.

  1. Modeling the Variations in TSI Using Precision Ground-Based Photometric Images

    NASA Astrophysics Data System (ADS)

    Chapman, G. A.; Walton, S. R.; Cookson, A. M.; Dobias, J. J.; Preminger, D. G.

    2002-12-01

    Precision photometric full-disk images of the sun have been obtained at the San Fernando Observatory (SFO) beginning in mid-1985. Images in several wavelengths are obtained daily but for modeling the Total Solar Irradiance (TSI) from spacecraft, the red (672 nm) and the K-line (393 nm) images have been the most useful. Two telescopes are in regular operation, Cartesian Full Disk Telescope (CFDT) number 1 and 2. They produce images that have 512 x 512 pixels and 1024 x 1024 pixels, respectively. Multiple linear regressions of sunspot deficits and facular excesses compared with Nimbus-7 and ACRIM-I values of TSI give values of R2 of from 0.80 to 0.85, depending on data intervals and the particular spacecraft. More recent fits to the composite TSI of Fröhlich and Lean for cycle 22 give values of R2 of 0.91. These fits are affected by noise in both ground-based and space-based data. This value of R2 suggests, especially considering the effects of noise, that less than 10% of the TSI variance is unexplained by the effects of sunspots and faculae/network. We are in the process of determining whether or not the coefficients from fits to cycle 22 TSI will also provide good fits to cycle 23 TSI. This research has been partially supported by grants from NSF (ATM-9912132) and NASA (NAG5-7191 and NAG5-7778).

  2. First Results of the Athena Microscopic Imager Investigation

    NASA Technical Reports Server (NTRS)

    Herkenhoff, K.; Squyres, S.; Archinal, B.; Arvidson, R.; Bass, D.; Barrett, J.; Becker, K.; Becker, T.; Bell, J., III; Burr, D.

    2004-01-01

    The Athena science payload on the Mars Exploration Rovers (MER) includes the Microscopic Imager (MI). The MI is a fixed-focus camera mounted on an extendable arm, the Instrument Deployment Device (IDD). The MI acquires images at a spatial resolution of 30 microns/pixel over a broad spectral range (400 - 700 nm). The MI uses the same electronics design as the other MER cameras but its optics yield a field of view of 31 x 31 mm across a 1024 x 1024 pixel CCD image. The MI acquires images using only solar or skylight illumination of the target surface. A contact sensor is used to place the MI slightly closer to the target surface than its best focus distance (about 69 mm), allowing concave surfaces to be imaged in good focus. Coarse focusing (approx. 2 mm precision) is achieved by moving the IDD away from a rock target after contact is sensed. The MI optics are protected from the Martian environment by a retractable dust cover. This cover includes a Kapton window that is tinted orange to restrict the spectral bandpass to 500 - 700 nm, allowing crude color information to be obtained by acquiring images with the cover open and closed. The MI science objectives, instrument design and calibration, operation, and data processing were described by Herkenhoff et al. Initial results of the MI experiment on both MER rovers ('Spirit' and 'Opportunity') are described below.

  3. VizieR Online Data Catalog: Catalog of X-ray sources in the NARCS (Fornasini+, 2014)

    NASA Astrophysics Data System (ADS)

    Fornasini, F. M.; Tomsick, J. A.; Bodaghee, A.; Krivonos, R. A.; An, H.; Rahoui, F.; Gotthelf, E. V.; Bauer, F. E.; Stern, D.

    2017-08-01

    We performed Chandra ACIS-I observations in faint mode of a 2°x0.8° region of the Norma spiral arm in 2011 June. The ACIS-I consists of four 1024x1024 pixel CCDs, covering a 17'x17' field of view (Garmire et al. 2003SPIE.4851...28G). The on-axis spatial resolution of the ACIS-I is fully sampled by the 0.492"x0.492" CCD pixel but it increases greatly off-axis. The PSF increases in size and becomes more elliptical at large off-axis angles, such that at an off-axis angle of 10', the PSF has ellipticity ~0.3 and semi-major axis ~15' for an enclosed-count fraction (ECF) of 90% for 4.5 keV photons (Allen et al. 2004SPIE.5165..423A). The CCDs are sensitive to incident photons with energies in the 0.3-10.0 keV range, and have a resolution of about 50-300 eV. The time resolution of the CCDs, which is determined by the read-out time, is 3.2 s. (3 data files).

  4. Plane-grating flat-field soft x-ray spectrometer

    SciTech Connect

    Hague, C.F.; Underwood, J.H.; Avila, A.; Delaunay, R.; Ringuenet, H.; Marsi, M.; Sacchi, M.

    2005-02-01

    We describe a soft x-ray spectrometer covering the 120-800 eV range. It is intended for resonant inelastic x-ray scattering experiments performed at third generation synchrotron radiation (SR) facilities and has been developed with SOLEIL, the future French national SR source in mind. The Hettrick-Underwood principle is at the heart of the design using a combination of varied line-spacing plane grating and spherical-mirror to provide a flat-field image. It is slitless for optimum acceptance. This means the source size determines the resolving power. A spot size of {<=}5 {mu}m is planned at SOLEIL which, according to simulations, should ensure a resolving power {>=}1000 over the whole energy range. A 1024x1024 pixel charge-coupled device (CCD) with a 13 {mu}mx13 {mu}m pixel size is used. This is an improvement on the use of microchannel-plate detectors, both as concerns efficiency and spatial resolution. Additionally spectral line curvature is avoided by the use of a horizontal focusing mirror concentrating the beam in the nondispersing direction. It allows for readout using a binning mode to reduce the intrinsically large CCD readout noise. Preliminary results taken at beamlines at Elettra (Trieste) and at BESSY (Berlin) are presented.

  5. Ultraviolet detector with CMOS-coupled microchannel plates for future space missions

    NASA Astrophysics Data System (ADS)

    Murakami, Go; Kuwabara, Masaki; Yoshioka, Kazuo; Hikida, Reina; Suzuki, Fumiharu; Yoshikawa, Ichiro

    2016-07-01

    The extreme ultraviolet (EUV) telescopes and spectrometers have been used as powerful tools in a variety of space applications, especially in planetary science. Many EUV instruments adopted microchannel plate (MCP) detection systems with resistive anode encoders (RAEs). An RAE is one of the position sensitive anodes suitable for space-based applications because of its low power, mass, and volume coupled with very high reliability. However, this detection system with RAE has limitations of resolution (up to 512 x 512 pixels) and incident count rate (up to 104 count/sec). Concerning the future space and planetary missions, a new detector with different position sensitive system is required in order to a higher resolution and dynamic range of incident photons. One of the solutions of this issue is using a CMOS imaging sensor. The CMOS imaging sensor with high resolution and high radiation tolerance has been widely used. Here we developed a new CMOS-coupled MCP detector for future UV space and planetary missions. It consists of MCPs followed by a phosphor screen, fiber optic plate, and a windowless CMOS. We manufactured a test model of this detector and performed vibration, thermal cycle, and performance tests. The test sample of FOP-coupled CMOS image sensor achieved the resolving limit of 32 lp/mm and the PSF of 28 um, corresponds to the spatial resolution of 1024 x 1024 pixels. Our results indicate that this new type of UV detector can be widely used for future space applications.

  6. Orion: The Largest Infrared Hybrid Focal Plane in Production

    NASA Astrophysics Data System (ADS)

    Fowler, Albert M.; Merrill, Michael; Ball, William J.; Henden, Arne A.; Vrba, Frederick J.; McCreight, Craig R.

    2003-03-01

    Orion is a program to develop a 2048x2048 infrared focal plane using InSb PV detectors. It is the natural follow-on to the successful Aladdin 1024x1024 program, which was the largest IR focal plane of the 90's. Although the pixels are somewhat smaller than Aladdin, the overall focal plane is over 50mm in size and for the present is the largest IR focal plane of the 21st century. The work is being done by Raytheon Infrared Operations (RIO but better known as SBRC) by many of the same people who created the Aladdin focal plane. The design is very similar to the successful Aladdin design with the addition of reference pixels to lower noise and drift effects in long integrations. So far we have made five focal plane modules with hybridized InSb detectors. In this paper we will discuss the unique design features of this device as well as present test data taken from these devices.

  7. First Results of the Athena Microscopic Imager Investigation

    NASA Technical Reports Server (NTRS)

    Herkenhoff, K.; Squyres, S.; Archinal, B.; Arvidson, R.; Bass, D.; Barrett, J.; Becker, K.; Becker, T.; Bell, J., III; Burr, D.

    2004-01-01

    The Athena science payload on the Mars Exploration Rovers (MER) includes the Microscopic Imager (MI). The MI is a fixed-focus camera mounted on an extendable arm, the Instrument Deployment Device (IDD). The MI acquires images at a spatial resolution of 30 microns/pixel over a broad spectral range (400 - 700 nm). The MI uses the same electronics design as the other MER cameras but its optics yield a field of view of 31 x 31 mm across a 1024 x 1024 pixel CCD image. The MI acquires images using only solar or skylight illumination of the target surface. A contact sensor is used to place the MI slightly closer to the target surface than its best focus distance (about 69 mm), allowing concave surfaces to be imaged in good focus. Coarse focusing (approx. 2 mm precision) is achieved by moving the IDD away from a rock target after contact is sensed. The MI optics are protected from the Martian environment by a retractable dust cover. This cover includes a Kapton window that is tinted orange to restrict the spectral bandpass to 500 - 700 nm, allowing crude color information to be obtained by acquiring images with the cover open and closed. The MI science objectives, instrument design and calibration, operation, and data processing were described by Herkenhoff et al. Initial results of the MI experiment on both MER rovers ('Spirit' and 'Opportunity') are described below.

  8. LMIRcam: an L/M-band imager for the LBT combined focus

    NASA Astrophysics Data System (ADS)

    Wilson, John C.; Hinz, Philip M.; Skrutskie, M. F.; Jones, Terry; Solheid, Elliott; Leisenring, Jarron; Garnavich, Peter; Kenworthy, Matthew; Nelson, Matthew J.; Woodward, Charles E.

    2008-07-01

    The L/M-band mid-InfraRed Camera (LMIRcam) will use a mid-wave (5.1 μm cut-off) Teledyne Imaging Systems HgCdTe HAWAII 1-RG array to image the coherently combined (Fizeau) focus of the Large Binocular Telescope's twin 8.4-meter primary mirrors generated by the University of Arizona's beam combiner - the Large Binocular Telescope Interferometer (LBTI). The 1024x1024 array will have a pixel scale of 10.9 milliarcsec (mas) per pixel and a field of view of 10"x10". The highest achievable angular resolution will be 26mas (34mas) for 3.6 μm (4.8 μm). LMIRcam will operate in parallel with the Nulling Infrared Camera (NIC), sharing the same Dewar. In addition to a suite of broad and narrow-band filters, LMIRcam will contain grisms for low-resolution spectroscopy, and serve as a test-bed for novel pupil masks to enable high-contrast imaging. The opto-mechanical design, anticipated performance, and a sample of potential science applications are presented. LMIRcam is funded by the National Science Foundation and the University of Virginia.

  9. Monolithic pixels on moderate resistivity substrate and sparsifying readout architecture

    NASA Astrophysics Data System (ADS)

    Giubilato, P.; Battaglia, M.; Bisello, D.; Caselle, M.; Chalmet, P.; Demaria, L.; Ikemoto, Y.; Kloukinas, K.; Mansuy, S. C.; Mattiazzo, S.; Marchioro, A.; Mugnier, H.; Pantano, D.; Potenza, A.; Rivetti, A.; Rousset, J.; Silvestrin, L.; Snoeys, W.

    2013-12-01

    The LePix projects aim realizing a new generation monolithic pixel detectors with improved performances at lesser cost with respect to both current state of the art monolithic and hybrid pixel sensors. The detector is built in a 90 nm CMOS process on a substrate of moderate resistivity. This allows charge collection by drift while maintaining the other advantages usually offered by MAPS, like having a single piece detector and using a standard CMOS production line. The collection by drift mechanism, coupled to the low capacitance design of the collecting node made possible by the monolithic approach, provides an excellent signal to noise ratio straight at the pixel cell together with a radiation tolerance far superior to conventional un-depleted MAPS. The excellent signal-to-noise performance is demonstrated by the device ability to separate the 6 keV 55Fe double peak at room temperature. To achieve high granularity (10-20 μm pitch pixels) over large detector areas maintaining high readout speed, a completely new compressing architecture has been devised. This architecture departs from the mainstream hybrid pixel sparsification approach, which uses in-pixel logic to reduce data, by using topological compression to minimize pixel area and power consumption.

  10. Intra-pixel response of infrared detector arrays for JWST

    NASA Astrophysics Data System (ADS)

    Hardy, Tim; Baril, M. R.; Pazder, J.; Stilburn, J. S.

    2008-07-01

    The near-infrared instruments on the James Webb Space Telescope will use 5 micron cutoff HAWAII-2RG detector arrays. We have investigated the response of this type of detector at sub-pixel resolution to determine whether variations at this scale would affect the performance of the instruments. Using a simple experimental setup we were able to get measurements with a resolution of approximately 4 microns. We have measured an un-hybridized HAWAII-1RG multiplexer, a hybridized HAWAII-1RG device with a 5 micron cutoff HgCdTe detector layer, and a hybridized HAWAII-2RG device with a 5 micron cutoff substrate-removed HgCdTe detector layer. We found that the intra-pixel response functions of the hybrid devices are basically smooth and well behaved, and vary little from pixel to pixel. However, we did find numerous sub-pixel sized defects, notably some long straight thin features like scratches. We were not able to detect any significant variations with wavelength between 0.65 and 2.2 microns, but in the -1RG device there was a variation with temperature. When cooled from 80K to 40K, the pixel response became narrower, and some signal began to be lost at the edges of the pixel. We believe this reflects a reduction in charge diffusion at the lower temperature.

  11. Performance limits of a single photon counting pixel system

    NASA Astrophysics Data System (ADS)

    Chmeissani, M.; Mikulec, B.

    2001-03-01

    X-ray imaging using hybrid pixel detectors in single photon counting mode is a relatively recent and exciting development. The photon counting mode implies that each pixel has a threshold in energy above which a hit is recorded. Sharing of charge between adjacent pixels would therefore lead to a loss of registered hits and for medical imaging applications to a higher patient dose. This explains why the demand for high spatial resolution and consequently small pixel sizes (<100 μm) motivates the Medipix2 collaboration to study the effects of charge sharing between pixels on system performance. Two different simulation codes are used to simulate the energy loss inside the detector and the charge transport towards the pixel electrodes. The largest contribution to the lateral spreading of charge comes from diffusion and can result in a considerable loss of detection efficiency in photon counting systems for small pixel sizes. The Medipix2 collaboration consists of groups from Barcelona, Cagliari, CEA/Leti DEIN, CERN, Freiburg, Glasgow, Mitthögskolan, Napoli, NIKHEF, MRC lab Cambridge, Pisa, Prague and Sassari.

  12. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, A.; Chen, J.; Pevtsov, A. A.

    2015-12-01

    Continued advances in solar observations have led to higher-resolution magnetograms and surface (photospheric) images, revealing bipolar magnetic features operating near the resolution limit during emerging flux events and other phenomena used to predict solar eruptions responsible for geomagnetic plasma disturbances. However, line of sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A pixel dynamics model utilizing Stokes I spectral profiles was previously-used to quantify changes in the Doppler shift, width, asymmetry, and tail flatness of Fe I lines at 6301.5 and 6302.5 Å and used pixel-by-pixel line profile fluctuations to characterize quiet and active regions on the Sun. We use this pixel dynamics model with circularly polarized photospheric data (e.g., SOLIS data) to estimate plasma dynamic properties at a sub-pixel level. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties on sub-pixel scales.

  13. Adhesive Testing for the BTeV Pixel Detector

    SciTech Connect

    Lei, C.M.; Kwan, Simon; Hicks, D.; Hahn, Eileen; Hoffman, Jay; Austin, Sharon; Jones, Renee; /Fermilab

    2005-12-01

    is needed to verify the compliancy. The demands for good thermal and electrical properties would be lessened in favor of the more important properties if conflicts arose in our decision. As the adhesive layer would be as thin as about 0.05 mm, the temperature drop across it would be small, so a lower number in thermal conductivity would be tolerable. Also, having a greater coefficient of thermal expansion (CTE) value for the adhesive would be acceptable, as long as the modulus is low enough so that high thermal stress would not be generated within the pixel module. For our testing purposes, some of the samples in these testing groups have been exposed to ionizing radiation. It is known that ionizing radiations incident on organic materials causes the formation of free radicals by rupturing covalent bonds. These radicals are chemically active and can form new bonds, altering the structure of the polymeric material and resulting in changes of its appearance and of the chemical, physical, and mechanical properties. It is thus important that some samples be subjected to ionizing radiation. Mechanical testing should be conducted on a group of samples to ensure that the mechanical properties are still acceptable after heavy radiation dosages. The results of these tests will portray a more accurate idea as to whether the material that will meet the expectations of the experiments in our unique environment.

  14. Monolithic pixel detectors with 0.2 μm FD-SOI pixel process technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu; Arai, Yasuo; Chiba, Tadashi; Fujita, Yowichi; Hara, Kazuhiko; Honda, Shunsuke; Igarashi, Yasushi; Ikegami, Yoichi; Ikemoto, Yukiko; Kohriki, Takashi; Ohno, Morifumi; Ono, Yoshimasa; Shinoda, Naoyuki; Takeda, Ayaki; Tauchi, Kazuya; Tsuboyama, Toru; Tadokoro, Hirofumi; Unno, Yoshinobu; Yanagihara, Masashi

    2013-12-01

    Truly monolithic pixel detectors were fabricated with 0.2 μm SOI pixel process technology by collaborating with LAPIS Semiconductor Co., Ltd. for particle tracking experiment, X-ray imaging and medical applications. CMOS circuits were fabricated on a thin SOI layer and connected to diodes formed in the silicon handle wafer through the buried oxide layer. We can choose the handle wafer and therefore high-resistivity silicon is also available. Double SOI (D-SOI) wafers fabricated from Czochralski (CZ)-SOI wafers were newly obtained and successfully processed in 2012. The top SOI layers are used as electric circuits and the middle SOI layers used as a shield layer against the back-gate effect and cross-talk between sensors and CMOS circuits, and as an electrode to compensate for the total ionizing dose (TID) effect. In 2012, we developed two SOI detectors, INTPIX5 and INTPIX3g. A spatial resolution study was done with INTPIX5 and it showed excellent performance. The TID effect study with D-SOI INTPIX3g detectors was done and we confirmed improvement of TID tolerance in D-SOI sensors.

  15. Monolithic pixel detectors in silicon on insulator technology

    SciTech Connect

    Bisello, Dario

    2013-05-06

    Silicon On Insulator (SOI) is becoming an attractive technology to fabricate monolithic pixel detectors. The possibility of using the depleted resistive substrate as a drift collection volume and to connect it by means of vias through the buried oxide to the pixel electronic makes this kind of approach interesting both for particle and photon detection. In this paper I report the results obtained in the development of monolithic pixel detectors in an SOI technology by a collaboration between groups from the University and INFN of Padova (Italy) and the LBNL and the SCIPP at UCSC (USA).

  16. Pixel detectors in 3D technologies for high energy physics

    SciTech Connect

    Deptuch, G.; Demarteau, M.; Hoff, J.; Lipton, R.; Shenai, A.; Yarema, R.; Zimmerman, T.; /Fermilab

    2010-10-01

    This paper reports on the current status of the development of International Linear Collider vertex detector pixel readout chips based on multi-tier vertically integrated electronics. Initial testing results of the VIP2a prototype are presented. The chip is the second embodiment of the prototype data-pushed readout concept developed at Fermilab. The device was fabricated in the MIT-LL 0.15 {micro}m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 {micro}m{sup 2} pixels, laid out in an array of 48 x 48 pixels.

  17. Consequences of Mixed Pixels on Temperature Emissivity Separation

    SciTech Connect

    Heasler, Patrick G.; Foley, Michael G.; Thompson, Sandra E.

    2007-02-01

    This report investigates the effect that a mixed pixel can have on temperature/emissivity seperation (i.e. temperature/emissivity estimation using long-wave infra-red data). Almost all temperature/emissivity estimation methods are based on a model that assumes both temperature and emissivity within the imaged pixel is homogeneous. A mixed pixel has heterogeneous temperature/emissivity and therefore does not satisfy the assumption. Needless to say, this heterogeneity causes biases in the estimates and this report quantifies the magnitude of the biases.

  18. Matching faces and expressions in pixelated and blurred photos.

    PubMed

    White, Murray; Li, Judy

    2006-01-01

    Matching the emotional expressions of pairs of face photos was slower with pixelated and blurred photos than with original, untransformed photos. Matching the identities of the same face pairs was unaffected by pixelation and blurring. Because pixelation and blurring degrade higher spatial frequencies carrying edge-based information that define feature shape more than lower frequencies carrying configural properties, these findings converge with findings for line drawings and negative photos in showing that expression and face recognition processes differ in their reliance on edge-based and configural information.

  19. Vertically integrated pixel readout chip for high energy physics

    SciTech Connect

    Deptuch, Grzegorz; Demarteau, Marcel; Hoff, James; Khalid, Farah; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom; /Fermilab

    2011-01-01

    We report on the development of the vertex detector pixel readout chips based on multi-tier vertically integrated electronics for the International Linear Collider. Some testing results of the VIP2a prototype are presented. The chip is the second iteration of the silicon implementation of the prototype, data-pushed concept of the readout developed at Fermilab. The device was fabricated in the 3D MIT-LL 0.15 {micro}m fully depleted SOI process. The prototype is a three-tier design, featuring 30 x 30 {micro}m{sup 2} pixels, laid out in an array of 48 x 48 pixels.

  20. The role of pixel detectors in high energy physics

    NASA Astrophysics Data System (ADS)

    Seiden, A.

    2016-12-01

    A number of new types of pixel detector systems have been pioneered in the last decade. These include new types of sensors as well as new electronics to allow much higher performance. At the same time new experiments are being planned or nearing completion covering a broad range of physics topics in flavour physics as well as large major upgrades at the LHC. These are planning to make use of the advances in pixel detectors in important ways. In this review both the pixel advances and how they enable the physics will be presented.

  1. Estimating pixel variances in the scenes of staring sensors

    DOEpatents

    Simonson, Katherine M [Cedar Crest, NM; Ma, Tian J [Albuquerque, NM

    2012-01-24

    A technique for detecting changes in a scene perceived by a staring sensor is disclosed. The technique includes acquiring a reference image frame and a current image frame of a scene with the staring sensor. A raw difference frame is generated based upon differences between the reference image frame and the current image frame. Pixel error estimates are generated for each pixel in the raw difference frame based at least in part upon spatial error estimates related to spatial intensity gradients in the scene. The pixel error estimates are used to mitigate effects of camera jitter in the scene between the current image frame and the reference image frame.

  2. Status and Construction of the Belle II DEPFET pixel system

    NASA Astrophysics Data System (ADS)

    Lütticke, Florian

    2014-06-01

    DEpleted P-channel Field Effect Transistor (DEPFET) active pixel detectors combine detection with a first amplification stage in a fully depleted detector, resulting in an superb signal-to-noise ratio even for thin sensors. Two layers of thin (75 micron) silicon DEPFET pixels will be used as the innermost vertex system, very close to the beam pipe in the Belle II detector at the SuperKEKB facility. The status of the 8 million DEPFET pixels detector, latest developments and current system tests will be discussed.

  3. Dual collection mode optical microscope with single-pixel detection

    NASA Astrophysics Data System (ADS)

    Rodríguez, A. D.; Clemente, P.; Fernández-Alonso, Mercedes; Tajahuerce, E.; Lancis, J.

    2015-07-01

    In this work we have developed a single-pixel optical microscope that provides both re ection and transmission images of the sample under test by attaching a diamond pixel layout DMD to a commercial inverted microscope. Our system performs simultaneous measurements of re ection and transmission modes. Besides, in contrast with a conventional system, in our single-element detection system both images belong, unequivocally, to the same plane of the sample. Furthermore, we have designed an algorithm to modify the shape of the projected patterns that improves the resolution and prevents the artifacts produced by the diamond pixel architecture.

  4. Monolithic pixel detectors in silicon on insulator technology

    NASA Astrophysics Data System (ADS)

    Bisello, Dario

    2013-05-01

    Silicon On Insulator (SOI) is becoming an attractive technology to fabricate monolithic pixel detectors. The possibility of using the depleted resistive substrate as a drift collection volume and to connect it by means of vias through the buried oxide to the pixel electronic makes this kind of approach interesting both for particle and photon detection. In this paper I report the results obtained in the development of monolithic pixel detectors in an SOI technology by a collaboration between groups from the University and INFN of Padova (Italy) and the LBNL and the SCIPP at UCSC (USA).

  5. A germanium hybrid pixel detector with 55μm pixel size and 65,000 channels

    NASA Astrophysics Data System (ADS)

    Pennicard, D.; Struth, B.; Hirsemann, H.; Sarajlic, M.; Smoljanin, S.; Zuvic, M.; Lampert, M. O.; Fritzsch, T.; Rothermund, M.; Graafsma, H.

    2014-12-01

    Hybrid pixel semiconductor detectors provide high performance through a combination of direct detection, a relatively small pixel size, fast readout and sophisticated signal processing circuitry in each pixel. For X-ray detection above 20 keV, high-Z sensor layers rather than silicon are needed to achieve high quantum efficiency, but many high-Z materials such as GaAs and CdTe often suffer from poor material properties or nonuniformities. Germanium is available in large wafers of extremely high quality, making it an appealing option for high-performance hybrid pixel X-ray detectors, but suitable technologies for finely pixelating and bump-bonding germanium have not previously been available. A finely-pixelated germanium photodiode sensor with a 256 by 256 array of 55μm pixels has been produced. The sensor has an n-on-p structure, with 700μm thickness. Using a low-temperature indium bump process, this sensor has been bonded to the Medipix3RX photoncounting readout chip. Tests with the LAMBDA readout system have shown that the detector works successfully, with a high bond yield and higher image uniformity than comparable high-Z systems. During cooling, the system is functional around -80°C (with warmer temperatures resulting in excessive leakage current), with -100°C sufficient for good performance.

  6. Characterization of a three side abuttable CMOS pixel sensor with digital pixel and data compression for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Guilloux, F.; Değerli, Y.; Flouzat, C.; Lachkar, M.; Monmarthe, E.; Orsini, F.; Venault, P.

    2016-02-01

    CMOS monolithic pixel sensor technology has been chosen to equip the new ALICE trackers for HL-LHC . PIXAM is the final prototype from an R&D program specific to the Muon Forward Tracker which intends to push significantly forward the performances of the mature rolling shutter architecture. By implementing a digital pixel allowing to readout of a group of rows in parallel, the PIXAM sensor increases the rolling shutter readout speed while keeping the same power consumption as that of analogue pixel sensors. This paper will describe shortly the ASIC architecture and will focus on the analogue and digital performances of the sensor, obtained from laboratory measurements.

  7. The Phase-1 upgrade of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Lipinski, M.

    2017-07-01

    The innermost tracking device of the CMS experiment is a silicon pixel detector. It has to cope with high particle fluxes and radiation damage, and was built to withstand the LHC design luminosity of 1×1034 cm-2s-1. This luminosity was already exceeded in 2016 and it is foreseen that it will increase further, potentially reaching two times the design value before 2018. Under such conditions the inefficiencies due to a limited readout bandwidth will increase by as much as 16% in the innermost layer. To maintain high tracking efficiency, the CMS collaboration has built a new pixel detector that was installed in March 2017. In this paper, the design of this so-called Phase-1 pixel detector is summarised, the production and the qualification of the pixel modules is described and the current status of the project is reported.

  8. STAR Vertex Detector Upgrade-HFT Pixel Development

    SciTech Connect

    Szelezniak, Michal; Greiner, Leo C.; Matis, Howard S.; Ritter, Hans Georg; Sun Xiangming; Thomas, James H.; Wieman, Howard H.; Anderssen, Eric; Stezelberger, Thorsten; Vu, Chinh Q.

    2009-03-10

    Development and prototyping efforts directed towards construction of a new vertex detector for the STAR experiment at the RHIC accelerator at BNL are presented. This new detector will extend the physics range of STAR by allowing for precision measurements of yields and spectra of particles containing heavy quarks. The innermost central part of the new detector is a high resolution pixel-type detector (PIXEL). PIXEL requirements are discussed as well as a conceptual mechanical design, a sensor development path, and a detector readout architecture. Selected progress with sensor prototypes dedicated to the PIXEL detector is summarized and the approach chosen for the readout system architecture validated in tests of hardware prototypes is discussed.

  9. Active pixel sensors with substantially planarized color filtering elements

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Kemeny, Sabrina E. (Inventor)

    1999-01-01

    A semiconductor imaging system preferably having an active pixel sensor array compatible with a CMOS fabrication process. Color-filtering elements such as polymer filters and wavelength-converting phosphors can be integrated with the image sensor.

  10. A pixel read-out chip for the PILATUS project

    NASA Astrophysics Data System (ADS)

    Brönnimann, Ch.; Baur, R.; Eikenberry, E. F.; Kohout, S.; Lindner, M.; Schmitt, B.; Horisberger, R.

    2001-06-01

    For the protein crystallography beamlime of the Swiss Light Source (SLS), which will be operational in summer 2001, the PILATUS detector ( PIxe L Appara TUs for the SLS) is currently being built. The goal of the PILATUS project is a hybrid pixel system with a size of 40×40 cm 2 having 2000×2000 pixels. The detector will be operated in single photon counting mode for 12 keV X-rays. The prototype pixel read-out chip has a noise of 75 e- with sensor, a low threshold dispersion and a maximum count rate of 1 MHz/pixel. Due to the expected radiation dose in operation at the beamline, the chip is designed in radiation hard DMILL technology.

  11. Application of a hybrid pixel detector to powder diffraction.

    PubMed

    Basolo, S; Bérar, J F; Boudet, N; Breugnon, P; Caillot, B; Clemens, J C; Delpierre, P; Dinkespiler, B; Hustache, S; Koudobine, I; Meessen, Ch; Menouni, M; Mouget, C; Palancher, H; Pangaud, P; Potheau, R; Vigeolas, E

    2007-01-01

    Results obtained using a hybrid pixel photon-counting detector in powder diffraction experiments are presented. The detector works at room temperature and its dynamic response ranges from 0.01 photons pixel(-1) s(-1) up to 10(6) photons pixel(-1) s(-1). The pixel sizes are 0.33 mm x 0.33 mm for a total area of 68 mm x 68 mm. On recording high-resolution diffraction patterns of powders, a reduction of the experimental time by more than a factor of 20 is obtained without loss of data quality. The example of an X-zeolite shows that such detectors can be used for very demanding anomalous experiments. In situ experiments of quenching liquid oxides show that frames of 0.01 s can be achieved for studying such processes.

  12. Bio-Inspired Asynchronous Pixel Event Tricolor Vision Sensor.

    PubMed

    Lenero-Bardallo, Juan Antonio; Bryn, D H; Hafliger, Philipp

    2014-06-01

    This article investigates the potential of the first ever prototype of a vision sensor that combines tricolor stacked photo diodes with the bio-inspired asynchronous pixel event communication protocol known as Address Event Representation (AER). The stacked photo diodes are implemented in a 22 × 22 pixel array in a standard STM 90 nm CMOS process. Dynamic range is larger than 60 dB and pixels fill factor is 28%. The pixels employ either simple pulse frequency modulation (PFM) or a Time-to-First-Spike (TFS) mode. A heuristic linear combination of the chip's inherent pseudo colors serves to approximate RGB color representation. Furthermore, the sensor outputs can be processed to represent the radiation in the near infrared (NIR) band without employing external filters, and to color-encode direction of motion due to an asymmetry in the update rates of the different diode layers.

  13. Improvement of Event Synchronization in the ATLAS Pixel Readout Development

    NASA Astrophysics Data System (ADS)

    Adams, Logan; Atlas Collaboration

    2017-01-01

    As the LHC continues in Run2, the B-Layer still uses the Atlas-SiROD Pixel readout system initially developed for Run 1. The higher luminosity occurring during Run 2 results in higher occupancy causing increased desynchronization errors in the Pixel Readout. In order to ensure lasting operation of the B-Layer until it is replaced after Run 3, changes were made to the firmware and software to add debug capabilities to identify when the errors are crossing certain thresholds and change the internal control logic accordingly. These features also allow for better debugging of the Event Counter Reset addition to the firmware. This talk will focus on the features implemented and measurements to demonstrate the positive impact on the Pixel DAQ system. A Pixel front-end chip emulator which can be used for readout system development beyond Run 3 will also be discussed. Presenter is Logan Adams, University of Washington.

  14. First Light with a 67-Million-Pixel WFI Camera

    NASA Astrophysics Data System (ADS)

    1999-01-01

    The newest astronomical instrument at the La Silla observatory is a super-camera with no less than sixty-seven million image elements. It represents the outcome of a joint project between the European Southern Observatory (ESO) , the Max-Planck-Institut für Astronomie (MPI-A) in Heidelberg (Germany) and the Osservatorio Astronomico di Capodimonte (OAC) near Naples (Italy), and was installed at the 2.2-m MPG/ESO telescope in December 1998. Following careful adjustment and testing, it has now produced the first spectacular test images. With a field size larger than the Full Moon, the new digital Wide Field Imager is able to obtain detailed views of extended celestial objects to very faint magnitudes. It is the first of a new generation of survey facilities at ESO with which a variety of large-scale searches will soon be made over extended regions of the southern sky. These programmes will lead to the discovery of particularly interesting and unusual (rare) celestial objects that may then be studied with large telescopes like the VLT at Paranal. This will in turn allow astronomers to penetrate deeper and deeper into the many secrets of the Universe. More light + larger fields = more information! The larger a telescope is, the more light - and hence information about the Universe and its constituents - it can collect. This simple truth represents the main reason for building ESO's Very Large Telescope (VLT) at the Paranal Observatory. However, the information-gathering power of astronomical equipment can also be increased by using a larger detector with more image elements (pixels) , thus permitting the simultaneous recording of images of larger sky fields (or more details in the same field). It is for similar reasons that many professional photographers prefer larger-format cameras and/or wide-angle lenses to the more conventional ones. The Wide Field Imager at the 2.2-m telescope Because of technological limitations, the sizes of detectors most commonly in use in

  15. Per-pixel energy calibration of photon counting detectors

    NASA Astrophysics Data System (ADS)

    Atharifard, A.; Healy, J. L.; Goulter, B. P.; Ramyar, M.; Vanden Broeke, L.; Walsh, M. F.; Onyema, C. C.; Panta, R. K.; Aamir, R.; Smithies, D. J.; Doesburg, R.; Anjomrouz, M.; Shamshad, M.; Bheesette, S.; Rajendran, K.; de Ruiter, N. J. A.; Knight, D.; Chernoglazov, A.; Mandalika, H.; Bell, S. T.; Bateman, C. J.; Butler, A. P. H.; Butler, P. H.

    2017-03-01

    Energy resolving performance of spectral CT systems is influenced by the accuracy of the detector's energy calibration. Global energy calibration maps a given threshold to the average energy response of all pixels of the detector. Variations arising from CMOS manufacturing processes and properties of the sensor cause different pixels to respond differently to photons of the same energy. Threshold dispersion adversely affects spectral imaging by degrading energy resolution, which contributes to blurring of the energy information. In this paper, we present a technique for per-pixel energy calibration of photon-counting x-ray detectors (PCXDs) that quantifies the energy response of individual pixels relative to the average response. This technique takes advantage of the measurements made by an equalized chip. It uses a known global energy map to quantify the effect of threshold dispersion on the energy response of the detector pixels across an energy range of interest. The proposed technique was assessed using a MARS scanner with an equalized Medipix3RX chip flip-bonded to 2 mm thick CdTe semiconductor crystal at a pitch of 110 μ m. Measurements were made of characteristic x-rays of a molybdenum foil. Results were compared between the case that the global calibration was used on its own and the case of using it in conjunction with our per-pixel calibration technique. The proposed technique quantified up to 1.87 keV error in energy response of 100 pixels of a selected region of interest (ROI). It made an improvement of 28.3% in average FWHM. The additional information provided by this per-pixel calibration technique can be used to improve spectral reconstruction.

  16. Measuring Pixel-Position Errors On CCD Imagers

    NASA Technical Reports Server (NTRS)

    Shaklan, Stuart B.; Shao, Mike; Gursel, Yekta; Yu, Jeffrey

    1995-01-01

    Deviations of positions of pixels on charge-coupled-device (CCD) image detector from nominal rectangular grid pattern measured by method in which coherent-light interference fringes used as reference pattern. Conceived for use in determining pixel-position errors in astrometric cameras flown aboard spacecraft. Also applied to determination of similar errors in (and calibration of) terrestrial CCD cameras used as position sensors; for example, position-measuring cameras that are parts of robotic systems.

  17. Offline calibrations and performance of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Langenegger, Urs; CMS Collaboration

    2011-09-01

    The CMS pixel detector, divided into barrel and endcap subdetectors, has 66 million pixels. We present the offline algorithms and results for the gain/pedestal and Lorentz angle calibrations. The determination of the optimal clock delay settings with initial data is described. The expected detector performance from Monte Carlo simulations is compared to the real performance in 7 TeV proton-proton collisions.

  18. A Chip and Pixel Qualification Methodology on Imaging Sensors

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Petkov, Mihail; Nguyen, Duc N.; Novak, Frank

    2004-01-01

    This paper presents a qualification methodology on imaging sensors. In addition to overall chip reliability characterization based on sensor s overall figure of merit, such as Dark Rate, Linearity, Dark Current Non-Uniformity, Fixed Pattern Noise and Photon Response Non-Uniformity, a simulation technique is proposed and used to project pixel reliability. The projected pixel reliability is directly related to imaging quality and provides additional sensor reliability information and performance control.

  19. Pixel History for Advanced Camera for Surveys Wide Field Channel

    NASA Astrophysics Data System (ADS)

    Borncamp, D.; Grogin, N.; Bourque, M.; Ogaz, S.

    2017-06-01

    Excess thermal energy present in a Charged Coupled Device (CCD) can result in additional electrical current. This excess charge is trapped within the silicon lattice structure of the CCD electronics. It can persist through multiple exposures and have an adverse effect on science performance of the detectors unless properly flagged and corrected for. The traditional way to correct for this extra charge is to take occasional long-exposure images with the camera shutter closed. These images, generally referred to as "dark" images, allow for the measurement of the thermal-electron contamination present in each pixel of the CCD lattice. This so-called "dark current" can then be subtracted from the science images by re-scaling the dark to the corresponding exposure times. Pixels that have signal above a certain threshold are traditionally marked as "hot" and flagged in the data quality array. Many users will discard these because of the extra current. However, these pixels may not be unusable because of an unreliable dark subtraction; if we find these pixels to be stable over an anneal period, we can properly subtract the charge and the extra Poisson noise from this dark current will be propagated into the error arrays. Here we present the results of a pixel history study that analyzes every individual pixel of the Hubble Space Telescope's (HST) Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) CCDs over time and allows pixels that were previously flagged as unusable to be brought back into the science image as a reliable pixel.

  20. FPIX2, the BTeV pixel readout chip

    SciTech Connect

    David C. Christian et al.

    2003-12-10

    A radiation tolerant pixel readout chip, FPIX2, has been developed at Fermilab for use by BTeV. Some of the requirements of the BTeV pixel readout chip are reviewed and contrasted with requirements for similar devices in LHC experiments. A description of the FPIX2 is given, and results of initial tests of its performance are presented, as is a summary of measurements planned for the coming year.

  1. Small pixel CZT detector for hard X-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Matthew David; Cernik, Robert; Chen, Henry; Hansson, Conny; Iniewski, Kris; Jones, Lawrence L.; Seller, Paul; Veale, Matthew C.

    2011-10-01

    A new small pixel cadmium zinc telluride (CZT) detector has been developed for hard X-ray spectroscopy. The X-ray performance of four detectors is presented and the detectors are analysed in terms of the energy resolution of each pixel. The detectors were made from CZT crystals grown by the travelling heater method (THM) bonded to a 20×20 application specific integrated circuit (ASIC) and data acquisition (DAQ) system. The detectors had an array of 20×20 pixels on a 250 μm pitch, with each pixel gold-stud bonded to an energy resolving circuit in the ASIC. The DAQ system digitised the ASIC output with 14 bit resolution, performing offset corrections and data storage to disc in real time at up to 40,000 frames per second. The detector geometry and ASIC design was optimised for X-ray spectroscopy up to 150 keV and made use of the small pixel effect to preferentially measure the electron signal. A 241Am source was used to measure the spectroscopic performance and uniformity of the detectors. The average energy resolution (FWHM at 59.54 keV) of each pixel ranged from 1.09±0.46 to 1.50±0.57 keV across the four detectors. The detectors showed good spectral performance and uniform response over almost all pixels in the 20×20 array. A large area 80×80 pixel detector will be built that will utilise the scalable design of the ASIC and the large areas of monolithic spectroscopic grade THM grown CZT that are now available. The large area detector will have the same performance as that demonstrated here.

  2. An adaptive regression method for infrared blind-pixel compensation

    NASA Astrophysics Data System (ADS)

    Chen, Suting; Meng, Hao; Pei, Tao; Zhang, Yanyan

    2017-09-01

    Blind pixel compensation is an ill-posed inverse problem of infrared imaging systems and image restoration. The performance of a blind pixel compensation algorithm depends on the accuracy of estimation for the underlying true infrared images. We propose an adaptive regression method (ARM) for blind pixel compensation that integrates the multi-scale framework with a regression model. A blind-pixel is restored by exploiting the intra-scale properties through the nonparametric regressive estimation and the inter-scale characteristics via parametric regression for continuous learning. Combining the respective strengths of a parametric model and a nonparametric model, ARM establishes a set of multi-scale blind-pixel compensation method to correct the non-uniformity based on key frame extraction. Therefore, it is essentially different from the traditional frameworks for blind pixel compensation which are based on filtering and interpolation. Experimental results on some challenging cases of blind compensation show that the proposed algorithm outperforms existing methods by a significant margin in both isolated blind restoration and clustered blind restoration.

  3. Frequency distribution signatures and classification of within-object pixels

    PubMed Central

    Stow, Douglas A.; Toure, Sory I.; Lippitt, Christopher D.; Lippitt, Caitlin L.; Lee, Chung-rui

    2011-01-01

    The premise of geographic object-based image analysis (GEOBIA) is that image objects are composed of aggregates of pixels that correspond to earth surface features of interest. Most commonly, image-derived objects (segments) or objects associated with predefined land units (e.g., agricultural fields) are classified using parametric statistical characteristics (e.g., mean and standard deviation) of the within-object pixels. The objective of this exploratory study was to examine the between- and within-class variability of frequency distributions of multispectral pixel values, and to evaluate a quantitative measure and classification rule that exploits the full pixel frequency distribution of within object pixels (i.e., histogram signatures) compared to simple parametric statistical characteristics. High spatial resolution Quickbird satellite multispectral data of Accra, Ghana were evaluated in the context of mapping land cover and land use and socioeconomic status. Results show that image objects associated with land cover and land use types can have characteristic, non-normal frequency distributions (histograms). Signatures of most image objects tended to match closely the training signature of a single class or sub-class. Curve matching approaches to classifying multi-pixel frequency distributions were found to be slightly more effective than standard statistical classifiers based on a nearest neighbor classifier. PMID:22408575

  4. Techniques for precise energy calibration of particle pixel detectors.

    PubMed

    Kroupa, M; Campbell-Ricketts, T; Bahadori, A; Empl, A

    2017-03-01

    We demonstrate techniques to improve the accuracy of the energy calibration of Timepix pixel detectors, used for the measurement of energetic particles. The typical signal from such particles spreads among many pixels due to charge sharing effects. As a consequence, the deposited energy in each pixel cannot be reconstructed unless the detector is calibrated, limiting the usability of such signals for calibration. To avoid this shortcoming, we calibrate using low energy X-rays. However, charge sharing effects still occur, resulting in part of the energy being deposited in adjacent pixels and possibly lost. This systematic error in the calibration process results in an error of about 5% in the energy measurements of calibrated devices. We use FLUKA simulations to assess the magnitude of charge sharing effects, allowing a corrected energy calibration to be performed on several Timepix pixel detectors and resulting in substantial improvement in energy deposition measurements. Next, we address shortcomings in calibration associated with the huge range (from kiloelectron-volts to megaelectron-volts) of energy deposited per pixel which result in a nonlinear energy response over the full range. We introduce a new method to characterize the non-linear response of the Timepix detectors at high input energies. We demonstrate improvement using a broad range of particle types and energies, showing that the new method reduces the energy measurement errors, in some cases by more than 90%.

  5. Techniques for precise energy calibration of particle pixel detectors

    NASA Astrophysics Data System (ADS)

    Kroupa, M.; Campbell-Ricketts, T.; Bahadori, A.; Empl, A.

    2017-03-01

    We demonstrate techniques to improve the accuracy of the energy calibration of Timepix pixel detectors, used for the measurement of energetic particles. The typical signal from such particles spreads among many pixels due to charge sharing effects. As a consequence, the deposited energy in each pixel cannot be reconstructed unless the detector is calibrated, limiting the usability of such signals for calibration. To avoid this shortcoming, we calibrate using low energy X-rays. However, charge sharing effects still occur, resulting in part of the energy being deposited in adjacent pixels and possibly lost. This systematic error in the calibration process results in an error of about 5% in the energy measurements of calibrated devices. We use FLUKA simulations to assess the magnitude of charge sharing effects, allowing a corrected energy calibration to be performed on several Timepix pixel detectors and resulting in substantial improvement in energy deposition measurements. Next, we address shortcomings in calibration associated with the huge range (from kiloelectron-volts to megaelectron-volts) of energy deposited per pixel which result in a nonlinear energy response over the full range. We introduce a new method to characterize the non-linear response of the Timepix detectors at high input energies. We demonstrate improvement using a broad range of particle types and energies, showing that the new method reduces the energy measurement errors, in some cases by more than 90%.

  6. High-voltage pixel sensors for ATLAS upgrade

    NASA Astrophysics Data System (ADS)

    Perić, I.; Kreidl, C.; Fischer, P.; Bompard, F.; Breugnon, P.; Clemens, J.-C.; Fougeron, D.; Liu, J.; Pangaud, P.; Rozanov, A.; Barbero, M.; Feigl, S.; Capeans, M.; Ferrere, D.; Pernegger, H.; Ristic, B.; Muenstermann, D.; Gonzalez Sevilla, S.; La Rosa, A.; Miucci, A.; Nessi, M.; Iacobucci, G.; Backhaus, M.; Hügging, Fabian; Krüger, H.; Hemperek, T.; Obermann, T.; Wermes, N.; Garcia-Sciveres, M.; Quadt, A.; Weingarten, J.; George, M.; Grosse-Knetter, J.; Rieger, J.; Bates, R.; Blue, A.; Buttar, C.; Hynds, D.

    2014-11-01

    The high-voltage (HV-) CMOS pixel sensors offer several good properties: a fast charge collection by drift, the possibility to implement relatively complex CMOS in-pixel electronics and the compatibility with commercial processes. The sensor element is a deep n-well diode in a p-type substrate. The n-well contains CMOS pixel electronics. The main charge collection mechanism is drift in a shallow, high field region, which leads to a fast charge collection and a high radiation tolerance. We are currently evaluating the use of the high-voltage detectors implemented in 180 nm HV-CMOS technology for the high-luminosity ATLAS upgrade. Our approach is replacing the existing pixel and strip sensors with the CMOS sensors while keeping the presently used readout ASICs. By intelligence we mean the ability of the sensor to recognize a particle hit and generate the address information. In this way we could benefit from the advantages of the HV sensor technology such as lower cost, lower mass, lower operating voltage, smaller pitch, smaller clusters at high incidence angles. Additionally we expect to achieve a radiation hardness necessary for ATLAS upgrade. In order to test the concept, we have designed two HV-CMOS prototypes that can be readout in two ways: using pixel and strip readout chips. In the case of the pixel readout, the connection between HV-CMOS sensor and the readout ASIC can be established capacitively.

  7. Accelerating sub-pixel marker segmentation using GPU

    NASA Astrophysics Data System (ADS)

    Handel, Holger

    2009-02-01

    Sub-pixel accurate marker segmentation is an important task for many computer vision systems. The 3D-positions of markers are used in control loops to determine the position of machine tools or robot end-effectors. Accurate segmentation of the marker position in the image plane is crucial for accurate reconstruction. Many subpixel segmentation algorithms are computationally intensive, especially when the number of markers increases. Modern graphics hardware with its massively parallel architecture provides a powerful tool for many image segmentation tasks. Especially, the time consuming sub-pixel refinement steps in marker segmentation can benefit from the recent progress. This article presents an implementation of a sub-pixel marker segmentation framework using the GPU to accelerate the processing time. The image segmentation chain consists of two stages. The first is a pre-processing stage which segments the initial position of the marker with pixel accuracy, the second stage refines the initial marker position to sub-pixel accuracy. Both stages are implemented as shader programs on the GPU. The flexible architecture allows it to combine different pre-processing and sub-pixel refinement algorithms. Experimental results show that significant speed-up can be achieved compared to CPU implementations, especially when the number of markers increases.

  8. Error-free demodulation of pixelated carrier frequency interferograms.

    PubMed

    Servin, M; Estrada, J C

    2010-08-16

    Recently, pixelated spatial carrier interferograms have been used in optical metrology and are an industry standard nowadays. The main feature of these interferometers is that each pixel over the video camera may be phase-modulated by any (however fixed) desired angle within [0,2pi] radians. The phase at each pixel is shifted without cross-talking from their immediate neighborhoods. This has opened new possibilities for experimental spatial wavefront modulation not dreamed before, because we are no longer constrained to introduce a spatial-carrier using a tilted plane. Any useful mathematical model to phase-modulate the testing wavefront in a pixel-wise basis can be used. However we are nowadays faced with the problem that these pixelated interferograms have not been correctly demodulated to obtain an error-free (exact) wavefront estimation. The purpose of this paper is to offer the general theory that allows one to demodulate, in an exact way, pixelated spatial-carrier interferograms modulated by any thinkable two-dimensional phase carrier.

  9. Fault tolerant photodiode and photogate active pixel sensors

    NASA Astrophysics Data System (ADS)

    Jung, Cory; Chapman, Glenn H.; La Haye, Michelle L.; Djaja, Sunjaya; Cheung, Desmond Y. H.; Lin, Henry; Loo, Edward; Audet, Yves R.

    2005-03-01

    As the pixel counts of digital imagers increase, the challenge of maintaining high yields and ensuring reliability over an imager"s lifetime increases. A fault tolerant active pixel sensor (APS) has been designed to meet this need by splitting an APS in half and operating both halves in parallel. The fault tolerant APS will perform normally in the no defect case and will produce approximately half the output for single defects. Thus, the entire signal can be recovered by multiplying the output by two. Since pixels containing multiple defects are rare, this design can correct for most defects allowing for higher production yields. Fault tolerant photodiode and photogate APS" were fabricated in 0.18-micron technology. Testing showed that the photodiode APS could correct for optically induced and electrically induced faults, within experimental error. The photogate APS was only tested for optically induced defects and also corrects for defects within experimental error. Further testing showed that the sensitivity of fault tolerant pixels was approximately 2-3 times more sensitive than the normal pixels. HSpice simulations of the fault tolerant APS circuit did not show increased sensitivity, however an equivalent normal APS circuit with twice width readout and row transistors was 1.90 times more sensitive than a normal pixel.

  10. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2003-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  11. Active pixel sensor having intra-pixel charge transfer with analog-to-digital converter

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Mendis, Sunetra K. (Inventor); Pain, Bedabrata (Inventor); Nixon, Robert H. (Inventor); Zhou, Zhimin (Inventor)

    2000-01-01

    An imaging device formed as a monolithic complementary metal oxide semiconductor Integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node and an analog-to-digital converter formed in the substrate connected to the output of the readout circuit.

  12. Enhancing head and helmet-mounted displays using a virtual pixel technology

    NASA Astrophysics Data System (ADS)

    Kading, Benjamin; Straub, Jeremy

    2015-05-01

    Head and helmet-mounted displays utilize pixels to display a digitized approximation of the real world. These displays must have a higher pixel density (as compared to a monitor or projected image) to create the same level of perceived resolution. This paper proposes a virtual pixel technology which incorporates a virtual pixel creation function. Each physical pixel's configuration is based on the virtual pixels that it contributes to, allowing lower pixel density display hardware to produce the approximation of a higher pixel density. The paper provides an overview of the proposed technology and how it is applicable to head/helmet-mounted displays and considerations related thereto.

  13. Modeling and analysis of hybrid pixel detector deficiencies for scientific applications

    NASA Astrophysics Data System (ADS)

    Fahim, Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-01

    Semiconductor hybrid pixel detectors often consist of a pixellated sensor layer bump bonded to a matching pixelated readout integrated circuit (ROIC). The sensor can range from high resistivity Si to III-V materials, whereas a Si CMOS process is typically used to manufacture the ROIC. Independent, device physics and electronic design automation (EDA) tools are used to determine sensor characteristics and verify functional performance of ROICs respectively with significantly different solvers. Some physics solvers provide the capability of transferring data to the EDA tool. However, single pixel transient simulations are either not feasible due to convergence difficulties or are prohibitively long. A simplified sensor model, which includes a current pulse in parallel with detector equivalent capacitor, is often used; even then, spice type top-level (entire array) simulations range from days to weeks. In order to analyze detector deficiencies for a particular scientific application, accurately defined transient behavioral models of all the functional blocks are required. Furthermore, various simulations, such as transient, noise, Monte Carlo, inter-pixel effects, etc. of the entire array need to be performed within a reasonable time frame without trading off accuracy. The sensor and the analog front-end can be modeling using a real number modeling language, as complex mathematical functions or detailed data can be saved to text files, for further top-level digital simulations. Parasitically aware digital timing is extracted in a standard delay format (sdf) from the pixel digital back-end layout as well as the periphery of the ROIC. For any given input, detector level worst-case and best-case simulations are performed using a Verilog simulation environment to determine the output. Each top-level transient simulation takes no more than 10-15 minutes. The impact of changing key parameters such as sensor Poissonian shot noise, analog front-end bandwidth, jitter due to

  14. Modeling and Analysis of Hybrid Pixel Detector Deficiencies for Scientific Applications

    SciTech Connect

    Fahim, Farah; Deptuch, Grzegorz W.; Hoff, James R.; Mohseni, Hooman

    2015-08-28

    Semiconductor hybrid pixel detectors often consist of a pixellated sensor layer bump bonded to a matching pixelated readout integrated circuit (ROIC). The sensor can range from high resistivity Si to III-V materials, whereas a Si CMOS process is typically used to manufacture the ROIC. Independent, device physics and electronic design automation (EDA) tools are used to determine sensor characteristics and verify functional performance of ROICs respectively with significantly different solvers. Some physics solvers provide the capability of transferring data to the EDA tool. However, single pixel transient simulations are either not feasible due to convergence difficulties or are prohibitively long. A simplified sensor model, which includes a current pulse in parallel with detector equivalent capacitor, is often used; even then, spice type top-level (entire array) simulations range from days to weeks. In order to analyze detector deficiencies for a particular scientific application, accurately defined transient behavioral models of all the functional blocks are required. Furthermore, various simulations, such as transient, noise, Monte Carlo, inter-pixel effects, etc. of the entire array need to be performed within a reasonable time frame without trading off accuracy. The sensor and the analog front-end can be modeling using a real number modeling language, as complex mathematical functions or detailed data can be saved to text files, for further top-level digital simulations. Parasitically aware digital timing is extracted in a standard delay format (sdf) from the pixel digital back-end layout as well as the periphery of the ROIC. For any given input, detector level worst-case and best-case simulations are performed using a Verilog simulation environment to determine the output. Each top-level transient simulation takes no more than 10-15 minutes. The impact of changing key parameters such as sensor Poissonian shot noise, analog front-end bandwidth, jitter due to

  15. Small pixel pitch MCT IR-modules

    NASA Astrophysics Data System (ADS)

    Lutz, H.; Breiter, R.; Eich, D.; Figgemeier, H.; Fries, P.; Rutzinger, S.; Wendler, J.

    2016-05-01

    It is only some years ago, since VGA format detectors in 15μm pitch, manufactured with AIM's MCT n-on-p LPE standard technology, have been introduced to replace TV/4 format detector arrays as a system upgrade. In recent years a rapid increase in the demand for higher resolution, while preserving high thermal resolution, compactness and low power budget is observed. To satisfy these needs AIM has realized first prototypes of MWIR XGA format (1024x768) detector arrays in 10μm pitch. They fit in the same compact dewar as 640x512, 15μm pitch detector arrays. Therefore, they are best suited for system upgrade purposes to benefit from higher spatial resolution and keep cost on system level low. By combining pitch size reduction with recent development progress in the fields of miniature cryocoolers, short dewars and high operating temperatures the way ahead to ultra-compact high performance MWIR-modules is prepared. For cost reduction MBE grown MCT on commercially available GaAs substrates is introduced at AIM. Recently, 640x512, 15μm pitch FPAs, grown with MBE have successfully passed long-term high temperature storage tests as a crucial step towards serial production readiness level for use in future products. Pitch size reduction is not limited to arrays sensitive in the MWIR, but is of great interest for high performance LWIR or 3rd Gen solutions. Some applications such as rotorcraft pilotage require superior spatial resolution in a compact design to master severe weather conditions or degraded visual environment such as brown-out. For these applications AIM is developing both LWIR as well as dual band detector arrays in HD-format (1280x720) with 12μm pitch. This paper will present latest results in the development of detector arrays with small pitch sizes of 10μm and 12μm at AIM, together with their usage to realize compact cooled IR-modules.

  16. Calibration status and plans for the charge integrating JUNGFRAU pixel detector for SwissFEL

    NASA Astrophysics Data System (ADS)

    Redford, S.; Bergamaschi, A.; Brückner, M.; Cartier, S.; Dinapoli, R.; Ekinci, Y.; Fröjdh, E.; Greiffenberg, D.; Mayilyan, D.; Mezza, D.; Mozzanica, A.; Rajeev, R.; Ramilli, M.; Ruder, C.; Schädler, L.; Schmitt, B.; Shi, X.; Thattil, D.; Tinti, G.; Zhang, J.

    2016-11-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector under development for photon science applications at free electron laser and synchrotron facilities. In particular, JUNGFRAU detectors will equip the Aramis end stations of SwissFEL, an X-ray free electron laser currently under construction at the Paul Scherrer Institut in Villigen, Switzerland. JUNGFRAU has been designed specifically to meet the challenges of photon science at XFELs, including high frame rates, single photon sensitivity in combination with a high dynamic range, vacuum compatibility and tilable modules. This has resulted in a charge integrating detector with three dynamically adjusting gains, a low noise of 55 ENC RMS, readout speeds in excess of 2 kHz, single photon sensitivity down to 2 keV (with a signal to noise ratio of 10) and a dynamic range covering four orders of magnitude at 12 keV. Each JUNGFRAU module consists of eight chips of 256 × 256 pixels, each 75 × 75 μm2 in size. The chips are arranged in 2 × 4 formation and bump-bonded to a single silicon sensor 320 μm thick, resulting in an active area of approximately 4 × 8 cm2 per module. Multi-module vacuum compatible systems comprising up to 16 Mpixels (32 modules) will be used at SwissFEL. The design of SwissFEL and the JUNGFRAU system for the Aramis end station A will be introduced, together with results from early prototypes and a characterisation using the first batch of final JUNGFRAU modules. Plans and first results of the pixel-by-pixel calibration will also be shown. The vacuum compatibility of the JUNGFRAU module is demonstrated for the first time.

  17. Smart pixel imaging with computational-imaging arrays

    NASA Astrophysics Data System (ADS)

    Fernandez-Cull, Christy; Tyrrell, Brian M.; D'Onofrio, Richard; Bolstad, Andrew; Lin, Joseph; Little, Jeffrey W.; Blackwell, Megan; Renzi, Matthew; Kelly, Mike

    2014-07-01

    Smart pixel imaging with computational-imaging arrays (SPICA) transfers image plane coding typically realized in the optical architecture to the digital domain of the focal plane array, thereby minimizing signal-to-noise losses associated with static filters or apertures and inherent diffraction concerns. MIT Lincoln Laboratory has been developing digitalpixel focal plane array (DFPA) devices for many years. In this work, we leverage legacy designs modified with new features to realize a computational imaging array (CIA) with advanced pixel-processing capabilities. We briefly review the use of DFPAs for on-chip background removal and image plane filtering. We focus on two digital readout integrated circuits (DROICS) as CIAs for two-dimensional (2D) transient target tracking and three-dimensional (3D) transient target estimation using per-pixel coded-apertures or flutter shutters. This paper describes two DROICs - a SWIR pixelprocessing imager (SWIR-PPI) and a Visible CIA (VISCIA). SWIR-PPI is a DROIC with a 1 kHz global frame rate with a maximum per-pixel shuttering rate of 100 MHz, such that each pixel can be modulated by a time-varying, pseudorandom, and duo-binary signal (+1,-1,0). Combining per-pixel time-domain coding and processing enables 3D (x,y,t) target estimation with limited loss of spatial resolution. We evaluate structured and pseudo-random encoding strategies and employ linear inversion and non-linear inversion using total-variation minimization to estimate a 3D data cube from a single 2D temporally-encoded measurement. The VISCIA DROIC, while low-resolution, has a 6 kHz global frame rate and simultaneously encodes eight periodic or aperiodic transient target signatures at a maximum rate of 50 MHz using eight 8-bit counters. By transferring pixel-based image plane coding to the DROIC and utilizing sophisticated processing, our CIAs enable on-chip temporal super-resolution.

  18. VeloPix: the pixel ASIC for the LHCb upgrade

    NASA Astrophysics Data System (ADS)

    Poikela, T.; De Gaspari, M.; Plosila, J.; Westerlund, T.; Ballabriga, R.; Buytaert, J.; Campbell, M.; Llopart, X.; Wyllie, K.; Gromov, V.; van Beuzekom, M.; Zivkovic, V.

    2015-01-01

    The LHCb Vertex Detector (VELO) will be upgraded in 2018 along with the other subsystems of LHCb in order to enable full readout at 40 MHz, with the data fed directly to the software triggering algorithms. The upgraded VELO is a lightweight hybrid pixel detector operating in vacuum in close proximity to the LHC beams. The readout will be provided by a dedicated front-end ASIC, dubbed VeloPix, matched to the LHCb readout requirements and the 55 × 55 μm VELO pixel dimensions. The chip is closely related to the Timepix3, from the Medipix family of ASICs. The principal challenge that the chip has to meet is a hit rate of up to 900 Mhits/s, resulting in a required output bandwidth of more than 16 Gbit/s. The occupancy across the chip is also very non-uniform, and the radiation levels reach an integrated 400 Mrad over the lifetime of the detector.VeloPix is a binary pixel readout chip with a data driven readout, designed in 130 nm CMOS technology. The pixels are combined into groups of 2 × 4 super pixels, enabling a shared logic and a reduction of bandwidth due to combined address and time stamp information. The pixel hits are combined with other simultaneous hits in the same super pixel, time stamped, and immediately driven off-chip. The analog front-end must be sufficiently fast to accurately time stamp the data, with a small enough dead time to minimize data loss in the most occupied regions of the chip. The data is driven off chip with a custom designed high speed serialiser. The current status of the ASIC design, the chip architecture and the simulations will be described.

  19. CMOS in-pixel optical pulse frequency modulator

    NASA Astrophysics Data System (ADS)

    Nel, Nicolaas E.; du Plessis, M.; Joubert, T.-H.

    2016-02-01

    This paper covers the design of a complementary metal oxide semiconductor (CMOS) pixel readout circuit with a built-in frequency conversion feature. The pixel contains a CMOS photo sensor along with all signal-to-frequency conversion circuitry. An 8×8 array of these pixels is also designed. Current imaging arrays often use analog-to-digital conversion (ADC) and digital signal processing (DSP) techniques that are off-chip1. The frequency modulation technique investigated in this paper is preferred over other ADC techniques due to its smaller size, and the possibility of a higher dynamic range. Careful considerations are made regarding the size of the components of the pixel, as various characteristics of CMOS devices are limited by decreasing the scale of the components2. The methodology used was the CMOS design cycle for integrated circuit design. All components of the pixel were designed from first principles to meet necessary requirements of a small pixel size (30×30 μm2) and an output resolution greater than that of an 8-bit ADC. For the photodetector, an n+-p+/p-substrate diode was designed with a parasitic capacitance of 3 fF. The analog front-end stage was designed around a Schmitt trigger circuit. The photo current is integrated on an integration capacitor of 200 fF, which is reset when the Schmitt trigger output voltage exceeds a preset threshold. The circuit schematic and layout were designed using Cadence Virtuoso and the process used was the AMS CMOS 350 nm process using a power supply of 5V. The simulation results were confirmed to comply with specifications, and the layout passed all verification checks. The dynamic range achieved is 58.828 dB per pixel, with the output frequencies ranging from 12.341kHz to 10.783 MHz. It is also confirmed that the output frequency has a linear relationship to the photocurrent generated by the photodiode.

  20. Pixel Analysis of Photospheric Spectral Data. I. Plasma Dynamics

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2016-11-01

    Recent observations of the photosphere using high spatial and temporal resolution show small dynamic features at or below the current resolving limits. A new pixel dynamics method has been developed to analyze spectral profiles and quantify changes in line displacement, width, asymmetry, and peakedness of photospheric absorption lines. The algorithm evaluates variations of line profile properties in each pixel and determines the statistics of such fluctuations averaged over all pixels in a given region. The method has been used to derive statistical characteristics of pixel fluctuations in observed quiet-Sun regions, an active region with no eruption, and an active region with an ongoing eruption. Using Stokes I images from the Vector Spectromagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) telescope on 2012 March 13, variations in line width and peakedness of Fe i 6301.5 Å are shown to have a distinct spatial and temporal relationship with an M7.9 X-ray flare in NOAA 11429. This relationship is observed as stationary and contiguous patches of pixels adjacent to a sunspot exhibiting intense flattening in the line profile and line-center displacement as the X-ray flare approaches peak intensity, which is not present in area scans of the non-eruptive active region. The analysis of pixel dynamics allows one to extract quantitative information on differences in plasma dynamics on sub-pixel scales in these photospheric regions. The analysis can be extended to include the Stokes parameters and study signatures of vector components of magnetic fields and coupled plasma properties.

  1. Argus: A W-band 16-pixel focal plane array for the Green Bank Telescope

    NASA Astrophysics Data System (ADS)

    Devaraj, Kiruthika; Church, Sarah; Cleary, Kieran; Frayer, David; Gawande, Rohit; Goldsmith, Paul; Gundersen, Joshua; Harris, Andrew; Kangaslahti, Pekka; Readhead, Tony; Reeves, Rodrigo; Samoska, Lorene; Sieth, Matt; Voll, Patricia

    2015-05-01

    We are building Argus, a 16-pixel square-packed focal plane array that will cover the 75-115.3 GHz frequency range on the Robert C. Byrd Green Bank Telescope (GBT). The primary research area for Argus is the study of star formation within our Galaxy and nearby galaxies. Argus will map key molecules that trace star formation, including carbon monoxide (CO) and hydrogen cyanide (HCN). An additional key science area is astrochemistry, which will be addressed by observing complex molecules in the interstellar medium, and the study of formation of solar systems, which will be addressed by identifying dense pre-stellar cores and by observing comets in our solar system. Argus has a highly scalable architecture and will be a technology path finder for larger arrays. The array is modular in construction, which will allow easy replacement of malfunctioning and poorly performing components.

  2. Effect of Pixel’s Spatial Characteristics on Recognition of Isolated Pixelized Chinese Character

    PubMed Central

    Yang, Kun; Liu, Shuang; Wang, Hong; Liu, Wei; Wu, Yaowei

    2015-01-01

    The influence of pixel’s spatial characteristics on recognition of isolated Chinese character was investigated using simulated prosthestic vision. The accuracy of Chinese character recognition with 4 kinds of pixel number (6*6, 8*8, 10*10, and 12*12 pixel array) and 3 kinds of pixel shape (Square, Dot and Gaussian) and different pixel spacing were tested through head-mounted display (HMD). A captured image of Chinese characters in font style of Hei were pixelized with Square, Dot and Gaussian pixel. Results showed that pixel number was the most important factor which could affect the recognition of isolated pixelized Chinese Chartars and the accuracy of recognition increased with the addition of pixel number. 10*10 pixel array could provide enough information for people to recognize an isolated Chinese character. At low resolution (6*6 and 8*8 pixel array), there were little difference of recognition accuracy between different pixel shape and different pixel spacing. While as for high resolution (10*10 and 12*12 pixel array), the fluctuation of pixel shape and pixel spacing could not affect the performance of recognition of isolated pixelized Chinese Character. PMID:26628934

  3. Observation of Quiet Limb in He I 1083.0 nm, H Paschen alpha1281.8 nm and H Brackett gamma 2166.1 nm lines

    NASA Astrophysics Data System (ADS)

    Prasad Choudhary, Debi

    2016-05-01

    In this paper, we shall present the results of an observational study of the quiet solar limb in the near infrared lines using the New IR Array Camera (NAC) and the vertical spectrograph at the focal plane of McMath-Pierce telescope. The NAC, at the exit port of the spectrograph, was used to record the limb spectrum in HeI 1083.0 nm, Hydrogen Paschen 1281.8 nm and Brackett 2165.5 nm wavelength regions. The NAC is a 1024x1024 InSb Alladin III Detector operating over 1-5 micron range with high density sampling at 0.018 arc second/pixel. The all-reflective optical train minimizes number of surfaces and eliminates ghosts leading to low scatter, ghost-free optics. The close-cycle cryogenic provides a stable cooling environment over six hour period with an accuracy of 0.01K leading to low dark current. The low read out noise combined with low scattered light and dark current makes NAC an ideal detector for making high quality infrared spectral observations of solar limb. The limb spectrums were obtained by placing the spectrograph slit perpendicular to the limb at an interval of 10 degrees around the solar disk. We shall report the intensity profile, line-of-sight velocity and line width distribution around the sun derived from the spectra along the slit.

  4. The EXOMARS High Resolution Camera (HRC) for Mars Landscape Observation and Soil Samples Inspection

    NASA Astrophysics Data System (ADS)

    Mosebach, Herbert; Gutruf, Sven; Glier, Markus; Michaelis, Harald; Schmitz, Nicole

    In co-operation with the DLR, Kayser-Threde is developing the High Resolution Camera (HRC) as one of the core scientific instruments on the EXOMARS rover. The HRC is part of the Panoramic Camera (PanCam) system, and the one with a high optical resolution. The main objectives of the camera are to observe interesting land sites on MARS, to assist the rover during locomotion. Additionally, the collected soil samples put by the drill into the sample tray of the rover shall be inspected before feeding the tray into the inside of the rover for scientific investigation. The camera is integrated inside the overall PanCam housing, which is located atop the rover mast as a cross bar. The instrument consists of a focus mechanism to adjust the focus range between 1 m and infinity. The FOV of the camera is 4.5 degrees, which leads to a resolution of about 0.8 mm at 10 m object distance. The camera is equipped with a 1024x1024 pixel detector, on which a RGB filter is applied. In this configuration colour images with the HRC are possible. placeMission launch is scheduled for early 2018. The landing on Mars is expected for the following year. This paper presents the objectives of the HRC camera, its optical and opto-mechanical design as well as the current development status.

  5. VizieR Online Data Catalog: HKs photometry in the Arches cluster (Espinoza+, 2009)

    NASA Astrophysics Data System (ADS)

    Espinoza, P.; Selman, F. J.; Melnick, J.

    2009-06-01

    The NAOS-CONICA data (ESO Program ID 073.D-0815) were obtained under clear weather conditions with subarcsecond seeing. The detector was an Aladdin 1024x1024 pixel InSb array and the camera had a plate scale of 27.15[mas/pix], giving us a 27x27arcsec2^ field of view of the Arches cluster. Total integration times were 1000, 400 and 720[s] in J, H, and Ks respectively, with the telescope moving alternatively to sky positions for a proper background subtraction. To optimize the Adaptive Optics (AO) performance we used the N90C10 dichroic, i.e. 90% of the light was directed to the infrared wavefront sensor. The Strehl ratio of our observations exceeded 27% in Ks, and reached more modest values of 5% in J, and 11% in the H band. Tables 2 and 3 present the DAOPHOT photometry of 427 HKS and 126 JHKS stars in the innermost 10 arcseconds of the Arches cluster. Table 3 is considerably shorter due to the increasing extinction towards bluer wavelengths. Table 5 presents the catalog with all the observed data and physical parameters derived from the Bayesian method and using the Color-magnitude stereogram. (3 data files).

  6. Motion compensation in digital subtraction angiography using graphics hardware.

    PubMed

    Deuerling-Zheng, Yu; Lell, Michael; Galant, Adam; Hornegger, Joachim

    2006-07-01

    An inherent disadvantage of digital subtraction angiography (DSA) is its sensitivity to patient motion which causes artifacts in the subtraction images. These artifacts could often reduce the diagnostic value of this technique. Automated, fast and accurate motion compensation is therefore required. To cope with this requirement, we first examine a method explicitly designed to detect local motions in DSA. Then, we implement a motion compensation algorithm by means of block matching on modern graphics hardware. Both methods search for maximal local similarity by evaluating a histogram-based measure. In this context, we are the first who have mapped an optimizing search strategy on graphics hardware while paralleling block matching. Moreover, we provide an innovative method for creating histograms on graphics hardware with vertex texturing and frame buffer blending. It turns out that both methods can effectively correct the artifacts in most case, as the hardware implementation of block matching performs much faster: the displacements of two 1024 x 1024 images can be calculated at 3 frames/s with integer precision or 2 frames/s with sub-pixel precision. Preliminary clinical evaluation indicates that the computation with integer precision could already be sufficient.

  7. Initial high-degree p-mode frequency splittings from the 1988 Mt. Wilson 60-foot Tower Solar Oscillation Program

    NASA Technical Reports Server (NTRS)

    Rhodes, Edward J., Jr.; Cacciani, Alessandro; Korzennik, Sylvain G.

    1988-01-01

    The initial frequency splitting results of solar p-mode oscillations obtained from the 1988 helioseismology program at the Mt. Wilson Observatory are presented. The frequency splittings correspond to the rotational splittings of sectoral harmonics which range in degree between 10 and 598. They were obtained from a cross-correlation analysis of the prograde and retrograde portions of a two-dimensional (t - v) power spectrum. This power spectrum was computed from an eight-hour sequence of full-disk Dopplergrams obtained on July 2, 1988, at the 60-foot tower telescope with a Na magneto-optical filter and a 1024x1024 pixel CCD camera. These frequency splittings have an inherently larger scatter than did the splittings obtained from earlier 16-day power spectra. These splittings are consistent with an internal solar rotational velocity which is independent of radius along the equatorial plane. The normalized frequency splittings averaged 449 + or - 3 nHz, a value which is very close to the observed equatorial rotation rate of the photospheric gas of 451.7 nHz.

  8. Near IR observations of Quiet Chromosphere

    NASA Astrophysics Data System (ADS)

    Prasad Choudhary, Debi; Deng, N.; Tejamoortula, U.; Penn, M. J.

    2009-05-01

    We have carried out the observations of quiet solar limb during April 29 to May 1, 2008, March 9-13, 2009 using the vertical spectrograph at the focal plane of McMath-Pierce telescope at Kitt Peak National Observatory. The solar limb was mostly featureless during the observations. The New Infrared Array (NAC) at the exit port of the spectrograph has been used to record the limb spectrum at HeI 1083.0 nm, Hydrogen Paschen beta at 1281.8 nm and Brackett gamma 2165.5 nm wavelength regions. The NAC is a 1024 x 1024 InSb Alladin III Detector operating over 1-5 micron range with high density sampling at 0.018 arc second/pixel. The all-reflective optical train minimizes number of surfaces and eliminates ghosts leading to low scatter, ghost-free optics. The close-cycle cryogenic provides a stable cooling environment over six hour period with an accuracy of about 0.01K leading to low dark current. The low read out noise combined with low scattered light and dark current makes NAC an ideal detector for making high quality infrared spectral observations of solar limb. In this presentation, we shall compare the line parameters of these lines around the solar disk. Acknowledgements: This work is supported by NSF under grant ATM 05-48952 and by NASA under grant NNX08AQ32G.

  9. Large amplitude tip/tilt estimation by geometric diversity for multiple-aperture telescopes

    NASA Astrophysics Data System (ADS)

    Vievard, S.; Cassaing, F.; Mugnier, L. M.

    2017-08-01

    A novel method nicknamed ELASTIC is proposed for the alignment of multiple-aperture telescopes, in particular segmented telescopes. It only needs the acquisition of two diversity images of an unresolved source, and is based on the computation of a modified, frequency-shifted, cross-spectrum. It provides a polychromatic large range tip/tilt estimation with the existing hardware and an inexpensive noniterative unsupervised algorithm. Its performance is studied and optimized by means of simulations. They show that with 5000 photo-electrons/sub-aperture/frame and 1024x1024 pixel images, residues are within the capture range of interferometric phasing algorithms such as phase diversity. The closed-loop alignment of a 6 sub-aperture mirror provides an experimental demonstration of the effectiveness of the method. Author accepted version. Final version is Copyright 2017 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited.

  10. Engineering performance of IRIS2 infrared imaging camera and spectrograph

    NASA Astrophysics Data System (ADS)

    Churilov, Vladimir; Dawson, John; Smith, Greg A.; Waller, Lew; Whittard, John D.; Haynes, Roger; Lankshear, Allan; Ryder, Stuart D.; Tinney, Chris G.

    2004-09-01

    IRIS2, the infrared imager and spectrograph for the Cassegrain focus of the Anglo Australian Telescope, has been in service since October 2001. IRIS2 incorporated many novel features, including multiple cryogenic multislit masks, a dual chambered vacuum vessel (the smaller chamber used to reduce thermal cycle time required to change sets of multislit masks), encoded cryogenic wheel drives with controlled backlash, a deflection compensating structure, and use of teflon impregnated hard anodizing for gear lubrication at low temperatures. Other noteworthy features were: swaged foil thermal link terminations, the pupil imager, the detector focus mechanism, phased getter cycling to prevent detector contamination, and a flow-through LN2 precooling system. The instrument control electronics was designed to allow accurate positioning of the internal mechanisms with minimal generation of heat. The detector controller was based on the AAO2 CCD controller, adapted for use on the HAWAII1 detector (1024 x 1024 pixels) and is achieving low noise and high performance. We describe features of the instrument design, the problems encountered and the development work required to bring them into operation, and their performance in service.

  11. The AstroBiology Explorer (ABE) MIDEX Mission Concept: Using Infrared Spectroscopy to Identify Organic Molecules in Space

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Ennico, Kimberly; Allamandola, Louis; Bregman, Jesse; Greene, Thomas; Hudgins, Douglas

    2002-01-01

    One of the principal means by which organic compounds are detected and identified in space is by infrared spectroscopy. Past IR telescopic and laboratory studies have shown that much of the carbon in the interstellar medium (ISM) is in complex organic species but the distribution, abundance and evolutionary relationships of these materials are not well understood. The Astrobiology Explorer (ABE) is a MIDEX mission concept designed to conduct IR spectroscopic observations to detect and identify these materials and address outstanding problems in astrobiology, astrochemistry, and astrophysics. ABE's core science program includes observations of planetary nebulae and stellar outflows, protostellar objects, Solar System objects, and galaxies, and lines of sight through dense molecular clouds and the diffuse ISM. ABE is a cryogenically-cooled 60 cm diameter space telescope equipped with 3 cross-dispersed R-2000 spectrometers that share a single common slit. Each spectrometer measures one spectral octave and together cover the entire 2.5-20 micron region simultaneously. The spectrometers use state-of-the-art InSb and Si:As 1024x1024 pixel detectors. ABE would operate in a heliocentric, Earth drift-away orbit and have a core science mission lasting approximately 1.5 years. ABE is currently under study at NASA's Ames Research Center in collaboration with Ball Aerospace and Technologies Corp.

  12. Initial high-degree p-mode frequency splittings from the 1988 Mt. Wilson 60-foot Tower Solar Oscillation Program

    NASA Technical Reports Server (NTRS)

    Rhodes, Edward J., Jr.; Cacciani, Alessandro; Korzennik, Sylvain G.

    1988-01-01

    The initial frequency splitting results of solar p-mode oscillations obtained from the 1988 helioseismology program at the Mt. Wilson Observatory are presented. The frequency splittings correspond to the rotational splittings of sectoral harmonics which range in degree between 10 and 598. They were obtained from a cross-correlation analysis of the prograde and retrograde portions of a two-dimensional (t - v) power spectrum. This power spectrum was computed from an eight-hour sequence of full-disk Dopplergrams obtained on July 2, 1988, at the 60-foot tower telescope with a Na magneto-optical filter and a 1024x1024 pixel CCD camera. These frequency splittings have an inherently larger scatter than did the splittings obtained from earlier 16-day power spectra. These splittings are consistent with an internal solar rotational velocity which is independent of radius along the equatorial plane. The normalized frequency splittings averaged 449 + or - 3 nHz, a value which is very close to the observed equatorial rotation rate of the photospheric gas of 451.7 nHz.

  13. Charge-coupled-device/fiberoptic taper array X-ray detector for protein crystallography

    SciTech Connect

    Naday, I.; Ross, S.; Westbrook, E.M.; Zentai, G.

    1997-03-01

    A large area, charge-couple-device (CCD) based fiberoptic taper array detector (APS-1) has been installed at the insertion-device beamline of the Structural Biology Center at the ANL Advanced Photon Source. The detector is used in protein crystallography diffraction experiments, where the objective is to measure the position and intensity of X-ray Bragg peaks in diffraction images. Large imaging area, very high spatial resolution, high X-ray sensitivity, good detective quantum efficiency, low noise, wide dynamic range, excellent stability and short readout time are all fundamental requirements in this application. The APS-1 detector converts the two-dimensional X-ray patterns to a visible light images by a thin layer of X-ray sensitive phosphor. The phosphor coating is directly deposited on the large ends of nine fiberoptic tapers arranged in a 3x3 array. Nine, thermoelectrically cooled 1024 x 1024 pixel CCD`s image the patterns, demagnified by the tapers. After geometrical and uniformity corrections, the nine areas give a continuous image of the detector face with virtually no gaps between the individual tapers. The 18 parallel analog signal-processing channels and analog-to-digital converters assure short readout time and low readout noise.

  14. Implementation of a cone-beam backprojection algorithm on the cell broadband engine processor

    NASA Astrophysics Data System (ADS)

    Bockenbach, Olivier; Knaup, Michael; Kachelrieß, Marc

    2007-03-01

    Tomographic image reconstruction is computationally very demanding. In all cases the backprojection represents the performance bottleneck due to the high operational count and due to the high demand put on the memory subsystem. In the past, solving this problem has lead to the implementation of specific architectures, connecting Application Specific Integrated Circuits (ASICs) or Field Programmable Gate Arrays (FPGAs) to memory through dedicated high speed busses. More recently, there have also been attempt to use Graphic Processing Units (GPUs) to perform the backprojection step. Originally aimed at the gaming market, IBM, Toshiba and Sony have introduced the Cell Broadband Engine (CBE) processor, often considered as a multicomputer on a chip. Clocked at 3 GHz, the Cell allows for a theoretical performance of 192 GFlops and a peak data transfer rate over the internal bus of 200 GB/s. This performance indeed makes the Cell a very attractive architecture for implementing tomographic image reconstruction algorithms. In this study, we investigate the relative performance of a perspective backprojection algorithm when implemented on a standard PC and on the Cell processor. We compare these results to the performance achievable with FPGAs based boards and high end GPUs. The cone-beam backprojection performance was assessed by backprojecting a full circle scan of 512 projections of 1024x1024 pixels into a volume of size 512x512x512 voxels. It took 3.2 minutes on the PC (single CPU) and is as fast as 13.6 seconds on the Cell.

  15. Evaluation of the Clinton Electronics DS2100HB-ST 4 X 3 Aspect Ratio, 21-Inch Diagonal Monochrome Monitor

    NASA Astrophysics Data System (ADS)

    2000-04-01

    The Clinton Electronics DS2100HB-ST Monochrome CRT Monitor (2 1-inch CRT size, 19.0" viewable area; the selling price is 1995) is a relatively low cost, 1600 x 1280 pixel, monochrome gray scale monitor. It has good image quality and features that make it an attractive candidate display device for NIMA Imagery Exploitation Capability workstations. Based on results of our evaluation, NIDL certifies the Clinton Electronics DS2100HB-ST monochrome monitor as being suitable only for monoscopic, and not for stereo, operation in IEC workstations. NIDL rates this monochrome monitor as a 'B' for monoscopic mode and 'F' for stereo mode for the Image Analyst and Cartographer applications. In stereo, this monitor can produce a 1024 x 1024 stereo image at 59 Hz per eye, but it has only 47% of the maximum luminance and only 44% of the stereo extinction ratio required by the IEC Specifications. Clinton states that the primary market for this lower cost monitor is for clinical tasks and for training purposes. It is not intended for primary diagnoses of x-ray images.

  16. Image processing pipeline for synchrotron-radiation-based tomographic microscopy.

    PubMed

    Hintermüller, C; Marone, F; Isenegger, A; Stampanoni, M

    2010-07-01

    With synchrotron-radiation-based tomographic microscopy, three-dimensional structures down to the micrometer level can be visualized. Tomographic data sets typically consist of 1000 to 1500 projections of 1024 x 1024 to 2048 x 2048 pixels and are acquired in 5-15 min. A processing pipeline has been developed to handle this large amount of data efficiently and to reconstruct the tomographic volume within a few minutes after the end of a scan. Just a few seconds after the raw data have been acquired, a selection of reconstructed slices is accessible through a web interface for preview and to fine tune the reconstruction parameters. The same interface allows initiation and control of the reconstruction process on the computer cluster. By integrating all programs and tools, required for tomographic reconstruction into the pipeline, the necessary user interaction is reduced to a minimum. The modularity of the pipeline allows functionality for new scan protocols to be added, such as an extended field of view, or new physical signals such as phase-contrast or dark-field imaging etc.

  17. The soft x ray telescope for Solar-A

    NASA Technical Reports Server (NTRS)

    Brown, W. A.; Acton, L. W.; Bruner, M. E.; Lemen, J. R.; Strong, K. T.

    1989-01-01

    The Solar-A satellite being prepared by the Institute for Sapce and Astronautical Sciences (ISAS) in Japan is dedicated to high energy observations of solar flares. The Soft X Ray Telescope (SXT) is being prepared to provide filtered images in the 2 to 60 A interval. The flight model is now undergoing tests in the 1000 foot tunnel at MSFC. Launch will be in September 1991. Earlier resolution and efficiency tests on the grazing incidence mirror have established its performance in soft x rays. The one-piece, two mirror grazing incidence telescope is supported in a strain free mount separated from the focal plane assembly by a carbon-epoxy metering tube whose windings and filler are chosen to minimize thermal and hygroscopic effects. The CCD detector images both the x ray and the concentric visible light aspect telescope. Optical filters provide images at 4308 and 4700 A. The SXT will be capable of producing over 8000 of the smallest partial frame images per day, or fewer but larger images, up to 1024 x 1024 pixel images. Image sequence with two or more of the five x ray analysis filters, with automatic exposure compensation to optimize the charge collection by the CCD detector, will be used to provide plasma diagnostics. Calculations using a differential emission measure code were used to optimize filter selection over the range of emission measure variations and to avoid redundancy, but the filters were chosen primarily to give ratios that are monotonic in plasma temperature.

  18. A Novel Compact Electron Spectrometer for Hot Electron Measurement in Pulsed Laser Solid Interaction

    SciTech Connect

    Chen, H; Patel, P; Price, D F; Young, B K; Springer, P T; Berry, R; Booth, R; Bruns, C; Nelson, D

    2002-07-05

    Ultra-intense laser-matter interactions provide a unique source of temporally short, broad spectrum electrons, which may be utilized in many varied applications. One such, which we are pursuing, is as part of a novel diagnostic to trace magnetic field lines in a magnetically-confined fusion device. An essential aspect of this scheme is to have a detailed characterization of the electron angular and energy distribution. To this effect we designed and constructed a compact electron spectrometer that uses permanent magnets for electron energy dispersion and over 100 scintillating fibers coupled to a 1024 x 1024 pixel CCD as the detection system. This spectrometer has electron energy coverage from 10 keV to 2 MeV. We tested the spectrometer on a high intensity (10{sup 17} to 10{sup 21} W/cm{sup 2}) short pulse (< 100 fs) laser, JanUSP, at Lawrence Livermore National laboratory using various solid targets. The details of the spectrometer and the experimental results will be reported.

  19. XAFS imaging of Tsukuba gabbroic rocks: area analysis of chemical composition and local structure.

    PubMed

    Mizusawa, Mari; Sakurai, Kenji

    2004-03-01

    Gabbroic rocks were collected at Mount Tsukuba in Japan, and their XAFS images were studied using a projection-type X-ray fluorescence (XRF) microscope, which is a powerful new tool recently developed for extremely rapid imaging. The instrument employs a grazing-incidence arrangement in order that primary X-rays illuminate the whole sample surface, as well as parallel-beam optics and an extremely close geometry in order to detect XRF by a high-performance X-ray CCD system with 1024 x 1024 pixels. The XRF image indicated that black amphibole and white feldspar, both of which are typical mineral textures of the rock, contain iron. The origin has been suggested to be several small yellowish-brown minerals contained there. The XAFS imaging has been carried out by repeating the exposure of XRF images during the energy scan of the primary X-rays. It has been found that the structure is qualitatively close to that of olivine, and the main differences found in both areas can be explained as a difference in iron and magnesium concentration, i.e. the mixed ratio of forsterite (Mg(2)SiO(4)) and fayalite (Fe(2)SiO(4)). The feasibility of the present XAFS imaging method has been demonstrated for realistic inhomogeneous minerals.

  20. A color graphics environment in support of supercomputer systems

    NASA Technical Reports Server (NTRS)

    Smith-Taylor, R.

    1985-01-01

    An initial step in the integration of an upgrade of a VPS-32 supercomputer to 16 million 64-bit words, to be closely followed by a further upgrade to 32 million words, was to develop a graphics language commonality with other computers at the Langley Center. The power of the upgraded supercomputer is to users at individual workstations, who will aid in defining the direction for future expansions in both graphics software and workstation requirements for the supercomputers. The LAN used is an ETHERNET configuration featuring both CYBER mainframe and PDP 11/34 image generator computers. The system includes a film recorder for image production in slide, CRT, 16 mm film, 35 mm film or polaroid film images. The workstations have screen resolutions of 1024 x 1024 with each pixel being one of 256 colors selected from a palette of 16 million colors. Each screen can have up to 8 windows open at a time, and is driven by a MC68000 microprocessor drawing on 4.5 Mb RAM, a 40 Mb hard disk and two floppy drives. Input is from a keyboard, digitizer pad, joystick or light pen. The system now allows researchers to view computed results in video time before printing out selected data.

  1. The astrobiology explorer (ABE) midex mission concept

    NASA Astrophysics Data System (ADS)

    Sandford, S.; Ennico, K.; Allamandola, L.; Bregman, J.; Greene, T.; Hudgins, D.

    One of the principal means by which organic compounds are detected and identified in space is by infrared spectroscopy. Past IR telescopic and laboratory studies have shown that much of the carbon in the interstellar medium (ISM) is in complex organic species, but the distribution, abundance, and evolutionary relationships of these materials are not well understood. The Astrobiology Explorer (ABE) is a MIDEX mission concept designed to conduct IR spectroscopic observations to detect and identify these materials and address outstanding problems in astrobiology, astrochemistry, and astrophysics. ABESs core science program includes observations of planetary nebulae and stellar outflows, protostellar objects, Solar System objects, and galaxies, and lines of sight through dense molecular clouds and the diffuse ISM. ABE is a cryogenicallycooled 60 cm diameter space telescope equipped with 3 cross-dispersed R~2000 spectrometers that share a single common slit. Each spectrometer measures one spectral octave and together cover the entire 2.5-20 micron region simultaneously. The spectrometers use state-of-the-art InSb and Si:As 1024x1024 pixel detectors. ABE would operate in a heliocentric, Earth drift-away orbit and have a core science mission lasting ~1.5 years. ABE is currently under study at NASA's Ames Research Center in collaboration with Ball Aerospace and Technologies Corp. This mission was selected by NASA for a feasibility study in April 2002.

  2. The AstroBiology Explorer (ABE) MIDEX Mission Concept: Using Infrared Spectroscopy to Identify Organic Molecules in Space

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Ennico, Kimberly; Allamandola, Louis; Bregman, Jesse; Greene, Thomas; Hudgins, Douglas

    2002-01-01

    One of the principal means by which organic compounds are detected and identified in space is by infrared spectroscopy. Past IR telescopic and laboratory studies have shown that much of the carbon in the interstellar medium (ISM) is in complex organic species but the distribution, abundance and evolutionary relationships of these materials are not well understood. The Astrobiology Explorer (ABE) is a MIDEX mission concept designed to conduct IR spectroscopic observations to detect and identify these materials and address outstanding problems in astrobiology, astrochemistry, and astrophysics. ABE's core science program includes observations of planetary nebulae and stellar outflows, protostellar objects, Solar System objects, and galaxies, and lines of sight through dense molecular clouds and the diffuse ISM. ABE is a cryogenically-cooled 60 cm diameter space telescope equipped with 3 cross-dispersed R-2000 spectrometers that share a single common slit. Each spectrometer measures one spectral octave and together cover the entire 2.5-20 micron region simultaneously. The spectrometers use state-of-the-art InSb and Si:As 1024x1024 pixel detectors. ABE would operate in a heliocentric, Earth drift-away orbit and have a core science mission lasting approximately 1.5 years. ABE is currently under study at NASA's Ames Research Center in collaboration with Ball Aerospace and Technologies Corp.

  3. Spectral imager based on Fabry-Perot interferometer for Aalto-1 nanosatellite

    NASA Astrophysics Data System (ADS)

    Mannila, Rami; Näsilä, Antti; Viherkanto, Kai; Holmlund, Christer; Näkki, Ismo; Saari, Heikki

    2013-09-01

    The Aalto-1 is a 3U-cubesat project coordinated by Aalto University. The satellite, Aalto-1, will be mainly built by students as project assignments and thesis works. The Aalto-1 is planned to launch on 2014. VTT Technical Research Centre of Finland is developing the main Earth observation payload, a miniaturized spectral imager unit, for the satellite. The spectral imager unit contains a spectral imager, a visible RGB-camera and control electronics of the cameras. Detailed design of the spectral imager unit has been completed and assembly of the spectral imager unit will be done in the autumn 2013. The spectral imager is based on a tunable Fabry-Perot interferometer (FPI) accompanied by an RGB CMOS image sensor. The FPI consists of two highly reflective surfaces separated by a tunable air gap and it is based on a piezo-actuated structure. The piezo-actuated FPI uses three piezo-actuators and is controlled in a closed capacitive feedback loop. The spectral resolution of the imager will be 8-15 nm at full width at half maximum and it will operate in the wavelength range 500-900 nm. Imaging resolution of the spectral imager is 1024x1024 pixels and the focal length of the optics is 32 mm and F-number is 3.4. Mass of the spectral imager unit is approximately 600 grams, and dimensions are 97 mm x 97 mm x 48 mm.

  4. Applications of an amorphous silicon-based area detector for high resolution, high sensitivity and fast time-resolved pair distribution function measurements.

    SciTech Connect

    Chupas, P. J.; Chapman, K. W.; Lee, P. L.; X-Ray Science Division

    2007-01-01

    The application of a large-area (41 x 41 cm, 2048 x 2048 or 1024 x 1024 pixel) high-sensitivity (detective quantum efficiency > 65%) fast-readout (up to 7.5 or 30 Hz) flat-panel detector based on an amorphous silicon array system to the collection of high-energy X-ray scattering data for quantitative pair distribution function (PDF) analysis is evaluated and discussed. Data were collected over a range of exposure times (0.13 s-7 min) for benchmark PDF samples: crystalline nickel metal and amorphous silica (SiO2). The high real-space resolution of the resultant PDFs (with Q{sub max} up to {approx} 40 Angstroms{sup -1})and the high quality of fits to data [RNi(0.13s) = 10.5%, RNi(1.3s) = 6.3%] obtained in short measurement times indicate that this detector is well suited to studies of materials disorder. Further applications of the detector to locate weakly scattering H2 molecules within the porous Prussian blue system, Mn{sup II}{sub 3}[CoIII(CN)6]2 x xH2, and to follow the in situ reduction of PtIVO2 to Pt0 at 30 Hz, confirm the high sensitivity of the detector and demonstrate a new potential for fast time-resolved studies.

  5. Bad pixel replacement based on spatial statistics for IR sensor

    NASA Astrophysics Data System (ADS)

    Meng, Xiang-long; Zhang, Wei; Cong, Ming-yu; Cao, Yi-ming; Bao, Wen-zhuo

    2010-10-01

    IR focal plane arrays typically contain bad pixels. Bad pixels have to be corrected because those can significantly impair the performance of target-detection algorithms. On the other hand, particularly as an aid to visual interpretation, it is desirable to replace the bad pixels. IR image contains spatial information and is correlative in spatial domain. In spatial statistics the semivariogram is an important function that relates semivariance to sampling lag. This function can characterize the spatial dependence of each point on its neighbor and provide a concise and unbiased description of the scale and pattern of spatial variability. One of the main reasons for deriving semivariogram is to use it in the process of estimation. Kriging is an interpolation and estimation technique that considers both the distance and the degree of variation between known data points when estimating values in unknown areas. In this paper a new technique based on spatial statistics is developed for bad pixel replacement. The main objective of the technique is to replace bad pixels through Kriging estimation. Theory analysis and experiments show that the method is reasonable and efficient.

  6. Super pixel density based clustering automatic image classification method

    NASA Astrophysics Data System (ADS)

    Xu, Mingxing; Zhang, Chuan; Zhang, Tianxu

    2015-12-01

    The image classification is an important means of image segmentation and data mining, how to achieve rapid automated image classification has been the focus of research. In this paper, based on the super pixel density of cluster centers algorithm for automatic image classification and identify outlier. The use of the image pixel location coordinates and gray value computing density and distance, to achieve automatic image classification and outlier extraction. Due to the increased pixel dramatically increase the computational complexity, consider the method of ultra-pixel image preprocessing, divided into a small number of super-pixel sub-blocks after the density and distance calculations, while the design of a normalized density and distance discrimination law, to achieve automatic classification and clustering center selection, whereby the image automatically classify and identify outlier. After a lot of experiments, our method does not require human intervention, can automatically categorize images computing speed than the density clustering algorithm, the image can be effectively automated classification and outlier extraction.

  7. Pixel-feature hybrid fusion for PET/CT images.

    PubMed

    Zhu, Yang-Ming; Nortmann, Charles A

    2011-02-01

    Color blending is a popular display method for functional and anatomic image fusion. The underlay image is typically displayed in grayscale, and the overlay image is displayed in pseudo colors. This pixel-level fusion provides too much information for reviewers to analyze quickly and effectively and clutters the display. To improve the fusion image reviewing speed and reduce the information clutter, a pixel-feature hybrid fusion method is proposed and tested for PET/CT images. Segments of the colormap are selectively masked to have a few discrete colors, and pixels displayed in the masked colors are made transparent. The colormap thus creates a false contouring effect on overlay images and allows the underlay to show through to give contours an anatomic context. The PET standardized uptake value (SUV) is used to control where colormap segments are masked. Examples show that SUV features can be extracted and blended with CT image instantaneously for viewing and diagnosis, and the non-feature part of the PET image is transparent. The proposed pixel-feature hybrid fusion highlights PET SUV features on CT images and reduces display clutters. It is easy to implement and can be used as complementarily to existing pixel-level fusion methods.

  8. Multiport solid-state imager characterization at variable pixel rates

    SciTech Connect

    Yates, G.J.; Albright, K.A.; Turko, B.T.

    1993-08-01

    The imaging performance of an 8-port Full Frame Transfer Charge Coupled Device (FFT CCD) as a function of several parameters including pixel clock rate is presented. The device, model CCD- 13, manufactured by English Electric Valve (EEV) is a 512 {times} 512 pixel array designed with four individual programmable bidirectional serial registers and eight output amplifiers permitting simultaneous readout of eight segments (128 horizontal {times} 256 vertical pixels) of the array. The imager was evaluated in Los Alamos National Laboratory`s High-Speed Solid-State Imager Test Station at true pixel rates as high as 50 MHz for effective imager pixel rates approaching 400 MHz from multiporting. Key response characteristics measured include absolute responsivity, Charge-Transfer-Efficiency (CTE), dynamic range, resolution, signal-to-noise ratio, and electronic and optical crosstalk among the eight video channels. Preliminary test results and data obtained from the CCD-13 will be presented and the versatility/capabilities of the test station will be reviewed.

  9. Application of pixel array detectors at x-ray synchrotrons.

    SciTech Connect

    Miceli, N.; X-Ray Science Division

    2009-03-01

    Pixel array detectors have only recently been seriously used at x-ray synchrotrons. We describe the application of a digital pixel array detector (Pilatus100k) to a variety of synchrotron experiments at the Advanced Photon Source at Argonne National Laboratory. The Pilatus100k was developed at the Paul Scherrer Institut (PSI). It has been commercialized by a PSI spinoff (Dectrics Ltd.) This is the first commercially available pixel array detector for x-ray synchrotron applications. The APS synchrotron provides tunable x-ray pulses with duration of {approx}80 ps and a repetition period of 153 ns (24-bunch mode). The Pilatus100k is a direct detection x-ray detector where each 172 micron pixel counts individual x-ray pulses above a lower threshold. It consists of {approx}100k pixels each of which is capable of single-photon counting (>3 keV) at count rates up to {approx}1 MHz. In addition, the Pilatus100k is an electronically gateable detector. We present data showing that the Pilatus100k is capable of isolating a single x-ray bunch at the APS in 24 bunch mode. We will also present a variety of different experiments exploiting the unique capabilities of the Pilatus100k.

  10. Software Implementation for the Characterization of Silicon Pixel Detectors

    NASA Astrophysics Data System (ADS)

    Miller, Kyle; Eusebi, Ricardo

    2011-10-01

    Pixel and Silicon-strip detectors are now a fundamental component for the detection, identification, and characterization of particles in nuclear and particle physics. They are used for beam diagnostics, for measurements of energy lost by electrons, for full-energy measurements of alphas and protons and heavy nuclei. The pixel and strip detectors are usually the most complex, sensitive, and expensive system in multi-million dollar detectors such as the ones in the Relativistic Heavy Ion Collider at Brookhaven. This poster describes the development of a characterization station for pixel and strip detectors in clean room at Texas A&M University. As a first step we describe the quantities to be measured for a full characterization of the pixel sensor, the identification of the needed electronic circuitry and the logic behind the control and readout of the system as a whole. The second stage shows the analysis of the obtained results from a set of next-generation radiation-hard pixel sensors. REU student from Florida A&M University.

  11. Visual mining business service using pixel bar charts

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Dayal, Umeshwar; Casati, Fabio

    2004-06-01

    Basic bar charts have been commonly available, but they only show highly aggregated data. Finding the valuable information hidden in the data is essential to the success of business. We describe a new visualization technique called pixel bar charts, which are derived from regular bar charts. The basic idea of a pixel bar chart is to present all data values directly instead of aggregating them into a few data values. Pixel bar charts provide data distribution and exceptions besides aggregated data. The approach is to represent each data item (e.g. a business transaction) by a single pixel in the bar chart. The attribute of each data item is encoded into the pixel color and can be accessed and drilled down to the detail information as needed. Different color mappings are used to represent multiple attributes. This technique has been prototyped in three business service applications-Business Operation Analysis, Sales Analysis, and Service Level Agreement Analysis at Hewlett Packard Laboratories. Our applications show the wide applicability and usefulness of this new idea.

  12. Fabrication and performance of mercuric iodide pixellated detectors

    NASA Astrophysics Data System (ADS)

    van den Berg, Lodewijk; Bastian, Lloyd F.; Zhang, Feng; Lenos, Howard; Capote, M. Albert

    2007-09-01

    The radiation detection efficiency and spectral resolution of mercuric iodide detectors can be improved significantly by increasing the volume of the detectors and by using a pixellated anode structure. Detector bodies with a thickness of nominally 10 mm and an active area of approximately 14 mm x 14 mm have been used for these experiments. The detectors were cut from single crystals grown by the physical vapor transport method. The cut surfaces were polished and etched using a string saw and potassium iodide solutions. The Palladium contacts were deposited by magnetron sputtering through stainless steel masks. The cathode contact is continuous; the anode contacts consist of an array of 11 x 11 pixels surrounded by a guard ring. The resistance between a pixel and its surrounding contacts should be larger than 0.25 Gohm. The detector is mounted on a substrate that makes it possible to connect the anode pixels to an ASIC, and is conditioned so that it is stable for all pixels at a bias of -3000 Volts. Under these conditions the spectral resolution for Cs-137 gamma rays (662 keV) is approximately 5% FWHM. When depth sensing correction methods are applied, the resolution improves to about 2% FWHM or better. It is expected that the performance of the devices can be improved by the careful selection of crystal parts that are free of structural defects. Details of the fabrication technologies will be described. The effects of material inhomogeneities and transport properties of the charge carriers will be discussed.

  13. The pixel tracking telescope at the Fermilab Test Beam Facility

    SciTech Connect

    Kwan, Simon; Lei, CM; Menasce, Dario; Moroni, Luigi; Ngadiuba, Jennifer; Prosser, Alan; Rivera, Ryan; Terzo, Stefano; Turqueti, Marcos; Uplegger, Lorenzo; Vigani, Luigi; Dinardo, Mauro E.

    2016-03-01

    An all silicon pixel telescope has been assembled and used at the Fermilab Test Beam Facility (FTBF) since 2009 to provide precise tracking information for different test beam experiments with a wide range of Detectors Under Test (DUTs) requiring high resolution measurement of the track impact point. The telescope is based on CMS pixel modules left over from the CMS forward pixel production. Eight planes are arranged to achieve a resolution of less than 8 μm on the 120 GeV proton beam transverse coordinate at the DUT position. In order to achieve such resolution with 100 × 150 μm2 pixel cells, the planes were tilted to 25 degrees to maximize charge sharing between pixels. Crucial for obtaining this performance is the alignment software, called Monicelli, specifically designed and optimized for this system. This paper will describe the telescope hardware, the data acquisition system and the alignment software constituting this particle tracking system for test beam users.

  14. Quantitative pixel grey measurement of the “high-risk” sign, darkening of third molar roots: a pilot study

    PubMed Central

    Szalma, J; Bata, Z; Lempel, E; Jeges, S; Olasz, L

    2013-01-01

    Objectives: Our aim was to examine the panoramic darkening of the root, which is a “high-risk” sign, using quantitative measurements of pixel grey values to determine different aetiological backgrounds, namely inferior alveolar nerve (IAN) exposure with or without groove formation of the third molar roots or thinning/fenestration of the lingual cortex (LCTF). Methods: 38 impacted third molars that had been surgically removed and had darkened roots on panoramic radiographs were included in this retrospective case–control study. 15 IAN exposure cases were selected for the case group, and 23 cases with proven lingual cortical thinning or fenestration were chosen for the control group. The mean pixel grey values of selected areas in the dark band (D) and control areas within the same roots (R) were determined with the ImageTool (University of Texas Health Science Center, San Antonio, TX) software. The differences in pixel values (R–D) of the IAN and LCTF groups were analysed using the Mann–Whitney U-test and Pearson's χ2 test. Results: The medians of the R–D pixel values were 45.7 in the IAN group and 34.3 in the LCTF group, whereas the interquartile ranges were 12.0 (IAN) and 18.3 (LCTF) (p < 0.001). The R–D critical value at which the outcomes differed significantly was 38. If the differences in pixel grey values (R–D) were higher than 38, the chance of IAN exposure was approximately 32 times higher than the chance of LCTF (χ2 test, p < 0.001; odds ratio, 32.0; 95% confidence interval, 3.5–293.1). Conclusions: The pre-operative prediction of IAN exposure or lingual cortical thinning in cases with “darkening” is possible based on pixel grey measurements of digital panoramic radiographs. PMID:23775927

  15. Method and apparatus of high dynamic range image sensor with individual pixel reset

    NASA Technical Reports Server (NTRS)

    Yadid-Pecht, Orly (Inventor); Pain, Bedabrata (Inventor); Fossum, Eric R. (Inventor)

    2001-01-01

    A wide dynamic range image sensor provides individual pixel reset to vary the integration time of individual pixels. The integration time of each pixel is controlled by column and row reset control signals which activate a logical reset transistor only when both signals coincide for a given pixel.

  16. Silicon pixel detector prototyping in SOI CMOS technology

    NASA Astrophysics Data System (ADS)

    Dasgupta, Roma; Bugiel, Szymon; Idzik, Marek; Kapusta, Piotr; Kucewicz, Wojciech; Turala, Michal

    2016-12-01

    The Silicon-On-Insulator (SOI) CMOS is one of the most advanced and promising technology for monolithic pixel detectors design. The insulator layer that is implemented inside the silicon crystal allows to integrate sensors matrix and readout electronic on a single wafer. Moreover, the separation of electronic and substrate increases also the SOI circuits performance. The parasitic capacitances to substrate are significantly reduced, so the electronic systems are faster and consume much less power. The authors of this presentation are the members of international SOIPIX collaboration, that is developing SOI pixel detectors in 200 nm Lapis Fully-Depleted, Low-Leakage SOI CMOS. This work shows a set of advantages of SOI technology and presents possibilities for pixel detector design SOI CMOS. In particular, the preliminary results of a Cracow chip are presented.

  17. Performance of the INTPIX6 SOI pixel detector

    NASA Astrophysics Data System (ADS)

    Arai, Y.; Bugiel, Sz.; Dasgupta, R.; Idzik, M.; Kapusta, P.; Kucewicz, W.; Miyoshi, T.; Turala, M.

    2017-01-01

    Characterization of the monolithic pixel detector INPTIX6, designed at KEK and fabricated in Lapis 0.2 μ m Fully-Depleted, Low-Leakage Silicon-On-Insulator (SOI) CMOS technology, was performed. The INTPIX6 comprises a large area of 1408 × 896 integrating type squared pixels of 12 micron pitch. In this work the performance and measurement results of the prototypes produced on lower resistivity Czochralski type (CZ-n) and high resistivity floating zone (FZ-n) sensor wafers are presented. Using 241Am radioactive source the noise of INTPIX6 was measured, showing the ENC (Equivalent Noise Charge) of about 70 e-. The resolution calculated from the FWHM of the Iron-55 X-ray peak was about 100 e-. The radiation hardness of the SOI pixel detector was also investigated. The CZ-n type INTPIX6 received a dose of 60 krad and its performance has been continuously monitored during the irradiation.

  18. Planar pixel sensors for the ATLAS upgrade: beam tests results

    NASA Astrophysics Data System (ADS)

    Weingarten, J.; Altenheiner, S.; Beimforde, M.; Benoit, M.; Bomben, M.; Calderini, G.; Gallrapp, C.; George, M.; Gibson, S.; Grinstein, S.; Janoska, Z.; Jentzsch, J.; Jinnouchi, O.; Kishida, T.; La Rosa, A.; Libov, V.; Macchiolo, A.; Marchiori, G.; Muenstermann, D.; Nagai, R.; Piacquadio, G.; Ristic, B.; Rubinskiy, I.; Rummler, A.; Takubo, Y.; Troska, G.; Tsiskaridtze, S.; Tsurin, I.; Unno, Y.; Weigell, P.; Wittig, T.

    2012-10-01

    The performance of planar silicon pixel sensors, in development for the ATLAS Insertable B-Layer and High Luminosity LHC (HL-LHC) upgrades, has been examined in a series of beam tests at the CERN SPS facilities since 2009. Salient results are reported on the key parameters, including the spatial resolution, the charge collection and the charge sharing between adjacent cells, for different bulk materials and sensor geometries. Measurements are presented for n+-in-n pixel sensors irradiated with a range of fluences and for p-type silicon sensors with various layouts from different vendors. All tested sensors were connected via bump-bonding to the ATLAS Pixel read-out chip. The tests reveal that both n-type and p-type planar sensors are able to collect significant charge even after the lifetime fluence expected at the HL-LHC.

  19. Simulation of Caliste-SO single pixel response

    NASA Astrophysics Data System (ADS)

    Barylak, J.; Barylak, A.; Mrozek, T.; Podgórski, P.; Steślicki, M.; Ścisłowski, D.

    2016-09-01

    The paper presents a method for determining the pixel response using Geant4 package. The response is calculated for cadmium telluride sensor of Caliste-SO detector. Caliste-SO will be used in STIX instrument on board Solar Orbiter, which is M-class mission of the ESA's program Cosmic Vision 2015-2025. Solar Orbiter is to be launched in October 2018. STIX instrument will provide imaging spectroscopy of solar hard X-ray emissions (4 - 150 keV) using a Fourier-imaging technique. Response of pixels in pixelized Caliste-SO detector vary between each other due to different sizes and locations. This can influence the scientific data obtained from STIX. Additionally, in the simulation we considered detector effects, like: hole tailing, damage layer, Fano and electronic noise.

  20. Leakage current measurements of a pixelated polycrystalline CVD diamond detector

    NASA Astrophysics Data System (ADS)

    Zain, R. M.; Maneuski, D.; O'Shea, V.; Bates, R.; Blue, A.; Cunnigham, L.; Stehl, C.; Berderman, E.; Rahim, R. A.

    2013-01-01

    Diamond has several desirable features when used as a material for radiation detection. With the invention of synthetic growth techniques, it has become feasible to look at developing diamond radiation detectors with reasonable surface areas. Polycrystalline diamond has been grown using a chemical vapour deposition (CVD) technique by the University of Augsburg and detector structures fabricated at the James Watt Nanofabrication Centre (JWNC) in the University of Glasgow in order to produce pixelated detector arrays. The anode and cathode contacts are realised by depositing gold to produce ohmic contacts. Measurements of I-V characteristics were performed to study the material uniformity. The bias voltage is stepped from -1000V to 1000V to investigate the variation of leakage current from pixel to pixel. Bulk leakage current is measured to be less than 1nA.

  1. Wire Bond Encapsulation for the CMS Forward Pixel Upgrade

    NASA Astrophysics Data System (ADS)

    Higginbotham, Sam; CMS Collaboration

    2015-04-01

    The Phase 1 upgrade of the pixel tracker for the CMS experiment will require the assembly of approximately 1000 modules consisting of pixel sensors bump bonded to readout chips. Electrical connections between the custom readout chips and support ASIC's that constitute the front-end of the pixel data acquisition system are made via wire bonds to a thin printed circuit board. Part of the assembly process carried out at Purdue University includes the partial encapsulation of the wire bonds for mechanical protection, prevention of electrolytic corrosion, and to damp oscillations due to Lorentz forces from transient current pulses in large magnetic fields. We present the details of the robotic assembly process which allows the deposition of the viscous encapsulant compound with 100 micron precision.

  2. Calculation of overlapping pixels for optical-butting focal plane

    NASA Astrophysics Data System (ADS)

    Li, Fuqiang; Chang, Junlei; Chu, Bei; Li, Na

    2016-10-01

    The resolution and observing width of optical remote sensing camera can be enhanced by increasing the detector length of focal plane. Optical butting is used to increase the imaging length owing to its simple structure, low cost and the simultaneously-imaging detectors. But butting process is influenced by many factors, which result in imaging gaps, so overlapping pixels between adjacent detectors is the key. In this paper, the factors causing imaging gap are analyzed, and calculation of overlapping pixel number is given out based on the analysis. Firstly an optical-butting focal plane system is built on optical imaging principles. Then the factors causing imaging gap are listed and analyzed, under the consideration of telecentric and non-telecentric optical system. Based on the imaging gap analysis, a formula for overlapping pixel number calculation is obtained, with the MTF assurance in vignetting districts resulted from optical butting. Finally a calculation example of a camera is given.

  3. Testbeam and laboratory characterization of CMS 3D pixel sensors

    NASA Astrophysics Data System (ADS)

    Bubna, M.; Bortoletto, D.; Alagoz, E.; Krzywda, A.; Arndt, K.; Shipsey, I.; Bolla, G.; Hinton, N.; Kok, A.; Hansen, T.-E.; Summanwar, A.; Brom, J. M.; Boscardin, M.; Chramowicz, J.; Cumalat, J.; Dalla Betta, G. F.; Dinardo, M.; Godshalk, A.; Jones, M.; Krohn, M. D.; Kumar, A.; Lei, C. M.; Mendicino, R.; Moroni, L.; Perera, L.; Povoli, M.; Prosser, A.; Rivera, R.; Solano, A.; Obertino, M. M.; Kwan, S.; Uplegger, L.; Vigani, L.; Wagner, S.

    2014-07-01

    The pixel detector is the innermost tracking device in CMS, reconstructing interaction vertices and charged particle trajectories. The sensors located in the innermost layers of the pixel detector must be upgraded for the ten-fold increase in luminosity expected at the High-Luminosity LHC (HL-LHC). As a possible replacement for planar sensors, 3D silicon technology is under consideration due to its good performance after high radiation fluence. In this paper, we report on pre- and post- irradiation measurements of CMS 3D pixel sensors with different electrode configurations from different vendors. The effects of irradiation on electrical properties, charge collection efficiency, and position resolution are discussed. Measurements of various test structures for monitoring the fabrication process and studying the bulk and surface properties of silicon sensors, such as MOS capacitors, planar and gate-controlled diodes are also presented.

  4. Virus based Full Colour Pixels using a Microheater

    PubMed Central

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-01-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future. PMID:26334322

  5. Visual mining geo-related data using pixel bar charts

    NASA Astrophysics Data System (ADS)

    Hao, Ming C.; Keim, Daniel A.; Dayal, Umeshwar; Wright, Peter; Schneidewind, Joern

    2005-03-01

    A common approach to analyze geo-related data is using bar charts or x-y plots. They are intuitive and easy to use. But important information often gets lost. In this paper, we introduce a new interactive visualization technique called Geo Pixel Bar Charts, which combines the advantages of Pixel Bar Charts and interactive maps. This technique allows analysts to visualize large amounts of spatial data without aggregation and shows the geographical regions corresponding to the spatial data attribute at the same time. In this paper, we apply Geo Pixel Bar Charts to visually mining sales transactions and Internet usage from different locations. Our experimental results show the effectiveness of this technique for providing data distribution and exceptions from the map.

  6. Calibration analysis software for the ATLAS Pixel Detector

    NASA Astrophysics Data System (ADS)

    Stramaglia, Maria Elena

    2016-07-01

    The calibration of the ATLAS Pixel Detector at LHC fulfils two main purposes: to tune the front-end configuration parameters for establishing the best operational settings and to measure the tuning performance through a subset of scans. An analysis framework has been set up in order to take actions on the detector given the outcome of a calibration scan (e.g. to create a mask for disabling noisy pixels). The software framework to control all aspects of the Pixel Detector scans and analyses is called calibration console. The introduction of a new layer, equipped with new FE-I4 chips, required an update of the console architecture. It now handles scans and scan analyses applied together to chips with different characteristics. An overview of the newly developed calibration analysis software will be presented, together with some preliminary results.

  7. The Phase-1 upgrade of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Klein, Katja

    2017-02-01

    The CMS experiment features a pixel detector with three barrel layers and two discs per side, corresponding to an active silicon area of 1 m2. The detector delivered high-quality data during LHC Run 1. However, the CMS pixel detector was designed for the nominal instantaneous LHC luminosity of 1 ·1034cm-2s-1 . It is expected that the instantaneous luminosity will increase and reach twice the design value before Long Shutdown 3, scheduled for 2023. Under such conditions, the present readout chip would suffer from data loss due to buffer overflow, leading to significant inefficiencies of up to 16%. The CMS collaboration is presently constructing a new pixel detector to replace the present device during the winter shutdown 2016/2017. The design of this new detector will be outlined, the construction status summarized and the performance described.

  8. Acousto-optic imaging with a smart-pixels sensor

    NASA Astrophysics Data System (ADS)

    Barjean, K.; Contreras, K.; Laudereau, J.-B.; Tinet, E.; Ettori, D.; Ramaz, F.; Tualle, J.-M.

    2015-03-01

    Acousto-optic imaging (AOI) is an emerging technique in the field of biomedical optics which combines the optical contrast allowed by diffuse optical tomography with the resolution of ultrasound (US) imaging. In this work we report the implementation, for that purpose, of a CMOS smart-pixels sensor dedicated to the real-time analysis of speckle patterns. We implemented a highly sensitive lock-in detection in each pixel in order to extract the tagged photons after an appropriate in-pixel post-processing. With this system we can acquire images in scattering samples with a spatial resolution in the 2mm range, with an integration time compatible with the dynamic of living biological tissue.

  9. HEXITEC ASIC—a pixellated readout chip for CZT detectors

    NASA Astrophysics Data System (ADS)

    Jones, Lawrence; Seller, Paul; Wilson, Matthew; Hardie, Alec

    2009-06-01

    HEXITEC is a collaborative project with the aim of developing a new range of detectors for high-energy X-ray imaging. High-energy X-ray imaging has major advantages over current lower energy imaging for the life and physical sciences, including improved phase-contrast images on larger, higher density samples and with lower accumulated doses. However, at these energies conventional silicon-based devices cannot be used, hence, the requirement for a new range of high Z-detector materials. Underpinning the HEXITEC programme are the development of a pixellated Cadmium Zinc Telluride (CZT) detectors and a pixellated readout ASIC which will be bump-bonded to the detector. The HEXITEC ASIC is required to have low noise (20 electrons rms) and tolerate detector leakage currents. A prototype 20×20 pixel ASIC has been developed and manufactured on a standard 0.35 μm CMOS process.

  10. Virus based Full Colour Pixels using a Microheater

    NASA Astrophysics Data System (ADS)

    Kim, Won-Geun; Kim, Kyujung; Ha, Sung-Hun; Song, Hyerin; Yu, Hyun-Woo; Kim, Chuntae; Kim, Jong-Man; Oh, Jin-Woo

    2015-09-01

    Mimicking natural structures has been received considerable attentions, and there have been a few practical advances. Tremendous efforts based on a self-assembly technique have been contributed to the development of the novel photonic structures which are mimicking nature’s inventions. We emulate the photonic structures from an origin of colour generation of mammalian skins and avian skin/feathers using M13 phage. The structures can be generated a full range of RGB colours that can be sensitively switched by temperature and substrate materials. Consequently, we developed an M13 phage-based temperature-dependent actively controllable colour pixels platform on a microheater chip. Given the simplicity of the fabrication process, the low voltage requirements and cycling stability, the virus colour pixels enable us to substitute for conventional colour pixels for the development of various implantable, wearable and flexible devices in future.

  11. Classification of multispectral image data by the Binary Diamond neural network and by nonparametric, pixel-by-pixel methods

    NASA Technical Reports Server (NTRS)

    Salu, Yehuda; Tilton, James

    1993-01-01

    The classification of multispectral image data obtained from satellites has become an important tool for generating ground cover maps. This study deals with the application of nonparametric pixel-by-pixel classification methods in the classification of pixels, based on their multispectral data. A new neural network, the Binary Diamond, is introduced, and its performance is compared with a nearest neighbor algorithm and a back-propagation network. The Binary Diamond is a multilayer, feed-forward neural network, which learns from examples in unsupervised, 'one-shot' mode. It recruits its neurons according to the actual training set, as it learns. The comparisons of the algorithms were done by using a realistic data base, consisting of approximately 90,000 Landsat 4 Thematic Mapper pixels. The Binary Diamond and the nearest neighbor performances were close, with some advantages to the Binary Diamond. The performance of the back-propagation network lagged behind. An efficient nearest neighbor algorithm, the binned nearest neighbor, is described. Ways for improving the performances, such as merging categories, and analyzing nonboundary pixels, are addressed and evaluated.

  12. Characterizing pixel and point patterns with a hyperuniformity disorder length

    NASA Astrophysics Data System (ADS)

    Chieco, A. T.; Dreyfus, R.; Durian, D. J.

    2017-09-01

    We introduce the concept of a "hyperuniformity disorder length" h that controls the variance of volume fraction fluctuations for randomly placed windows of fixed size. In particular, fluctuations are determined by the average number of particles within a distance h from the boundary of the window. We first compute special expectations and bounds in d dimensions, and then illustrate the range of behavior of h versus window size L by analyzing several different types of simulated two-dimensional pixel patterns—where particle positions are stored as a binary digital image in which pixels have value zero if empty and one if they contain a particle. The first are random binomial patterns, where pixels are randomly flipped from zero to one with probability equal to area fraction. These have long-ranged density fluctuations, and simulations confirm the exact result h =L /2 . Next we consider vacancy patterns, where a fraction f of particles on a lattice are randomly removed. These also display long-range density fluctuations, but with h =(L /2 )(f /d ) for small f , and h =L /2 for f →1 . And finally, for a hyperuniform system with no long-range density fluctuations, we consider "Einstein patterns," where each particle is independently displaced from a lattice site by a Gaussian-distributed amount. For these, at large L ,h approaches a constant equal to about half the root-mean-square displacement in each dimension. Then we turn to gray-scale pixel patterns that represent simulated arrangements of polydisperse particles, where the volume of a particle is encoded in the value of its central pixel. And we discuss the continuum limit of point patterns, where pixel size vanishes. In general, we thus propose to quantify particle configurations not just by the scaling of the density fluctuation spectrum but rather by the real-space spectrum of h (L ) versus L . We call this approach "hyperuniformity disorder length spectroscopy".

  13. Pixel Detectors For Diffraction Experiments At The Swiss Light Source

    SciTech Connect

    Huelsen, G.; Eikenberry, E.F.; Schmitt, B.; Schulze-Briese, C.; Tomizaki, T.; Stampanoni, M.; Willmott, P.; Patterson, B.; Broennimann, Ch.; Horisberger, R.; Toyokawa, H.; Borchert, G. L.

    2004-05-12

    The PILATUS detector (Pixel Apparatus for the SLS) is a large, quantum-limited area X-ray detector for protein crystallography which is currently under construction. Its basic units are modules with 16 CMOS chips bump-bonded to a large, continuously sensitive silicon sensor with 157x366 pixels of 217x217 {mu}m2, leading to an active area of 34x80 mm2. With a counting circuit in each pixel, X-rays are detected in single photon counting mode, leading to excellent, noise-free data. The main properties of the detector are an energy range of 6 to 30 keV, no back-ground due to leakage current or readout-noise, fast read-out time of 6.7 ms, a rate/pixel >104/s and a PSF of one pixel. PILATUS detectors are installed at the SLS X06SA protein crystallography beamline, and at both the surface diffraction (SD) station and the radiography and tomography (XTM) station of beamline X04SA. The detectors are operated at room temperature and thus are very easy to use. Experiments benefit from the ability to detect very weak diffraction spots with high precision. At the SD station and at the XTM station, which is equipped with a Bragg magnifier, diffraction, radiography and tomography experiments showed promising results. At beamline X06SA, a three-module array (1120x157 pixels) with a readout time of 6.7 ms was tested. This system was used to collect fine phi-sliced protein crystal data in continuous sample rotation mode in which the crystal was continuously rotated with a slow angular velocity of 0.04 deg./s without any shutter operation. Exposure time per frame ranged from 100 ms to a few seconds, depending on the crystal. These initial experiments show the potential of this method.

  14. Pixel Detectors For Diffraction Experiments At The Swiss Light Source

    NASA Astrophysics Data System (ADS)

    Hülsen, G.; Eikenberry, E. F.; Horisberger, R.; Schmitt, B.; Schulze-Briese, C.; Tomizaki, T.; Toyokawa, H.; Stampanoni, M.; Borchert, G. L.; Willmott, P.; Patterson, B.; Brönnimann, Ch.

    2004-05-01

    The PILATUS detector (Pixel Apparatus for the SLS) is a large, quantum-limited area X-ray detector for protein crystallography which is currently under construction. Its basic units are modules with 16 CMOS chips bump-bonded to a large, continuously sensitive silicon sensor with 157×366 pixels of 217×217 μm2, leading to an active area of 34×80 mm2. With a counting circuit in each pixel, X-rays are detected in single photon counting mode, leading to excellent, noise-free data. The main properties of the detector are an energy range of 6 to 30 keV, no back-ground due to leakage current or readout-noise, fast read-out time of 6.7 ms, a rate/pixel >104/s and a PSF of one pixel. PILATUS detectors are installed at the SLS X06SA protein crystallography beamline, and at both the surface diffraction (SD) station and the radiography and tomography (XTM) station of beamline X04SA. The detectors are operated at room temperature and thus are very easy to use. Experiments benefit from the ability to detect very weak diffraction spots with high precision. At the SD station and at the XTM station, which is equipped with a Bragg magnifier, diffraction, radiography and tomography experiments showed promising results. At beamline X06SA, a three-module array (1120×157 pixels) with a readout time of 6.7 ms was tested. This system was used to collect fine phi-sliced protein crystal data in continuous sample rotation mode in which the crystal was continuously rotated with a slow angular velocity of 0.04 °/s without any shutter operation. Exposure time per frame ranged from 100 ms to a few seconds, depending on the crystal. These initial experiments show the potential of this method.

  15. Imaging by photon counting with 256x256 pixel matrix

    NASA Astrophysics Data System (ADS)

    Tlustos, Lukas; Campbell, Michael; Heijne, Erik H. M.; Llopart, Xavier

    2004-09-01

    Using 0.25µm standard CMOS we have developed 2-D semiconductor matrix detectors with sophisticated functionality integrated inside each pixel of a hybrid sensor module. One of these sensor modules is a matrix of 256x256 square 55µm pixels intended for X-ray imaging. This device is called 'Medipix2' and features a fast amplifier and two-level discrimination for signals between 1000 and 100000 equivalent electrons, with overall signal noise ~150 e- rms. Signal polarity and comparator thresholds are programmable. A maximum count rate of nearly 1 MHz per pixel can be achieved, which corresponds to an average flux of 3x10exp10 photons per cm2. The selected signals can be accumulated in each pixel in a 13-bit register. The serial readout takes 5-10 ms. A parallel readout of ~300 µs could also be used. Housekeeping functions such as local dark current compensation, test pulse generation, silencing of noisy pixels and threshold tuning in each pixel contribute to the homogeneous response over a large sensor area. The sensor material can be adapted to the energy of the X-rays. Best results have been obtained with high-resistivity silicon detectors, but also CdTe and GaAs detectors have been used. The lowest detectable X-ray energy was about 4 keV. Background measurements have been made, as well as measurements of the uniformity of imaging by photon counting. Very low photon count rates are feasible and noise-free at room temperature. The readout matrix can be used also with visible photons if an energy or charge intensifier structure is interposed such as a gaseous amplification layer or a microchannel plate or acceleration field in vacuum.

  16. Accuracy of the Independent Pixel Approximation at Absorbing Wavelengths

    NASA Technical Reports Server (NTRS)

    Marchak, Alexander; Oreopoulos, Lazaros; Davis, Anthony; Wiscombe, Warren; Cahalan, Robert

    1999-01-01

    In order to correctly interpret shortwave cloud radiation measured by satellites and ground-based radiometers, or by two aircraft flying above and below clouds, we need to better understand interactions between inhomogeneous clouds and solar radiation. The discrepancies between shortwave absorption inferred from measurements and predicted by models, between cloud optical depths estimated from satellites and ground measurements, between single scattering albedo retrieved from in situ radiation measurements and computed from measured droplet size distribution, among others, are strongly affected by cloud horizontal inhomogeneity. Net horizontal photon transport (i. e., horizontal fluxes) are a direct consequence of the inhomoqeneity in cloud structure. Horizontal fluxes and their effect on the accuracy of the pixel-by-pixel one-dimensional (1 D) radiative transfer calculations has recently undergone close scrutiny for conservative scattering. However, the properties and magnitude of horizontal fluxes in absorbing wavelengths are still poorly understood. As far as we are aware, only Ackerman and Cox and Titov discussed correlations between horizontal fluxes at absorbing wavelengths, though these were far from comprehensive. This paper partly fills this gap. We discuss here of whether the accuracy of the Independent Pixel Approximation (IPA), a 1 D radiative transfer approximation for each pixel, is a better model for multiple scattering at conservative or at absorbing wavelengths. Issues addressed here are: (1) dependence of net horizontal fluxes on single scattering albedo; (2) connection between pixel-by-pixel accuracy of the IPA and horizontal fluxes and (3) radiative smoothing and horizontal fluxes at absorbing wavelengths. In contrast to the traditional understanding of IPA, we study IPA accuracies not only for reflectance but also for transmittance and absorptance at both conservative and absorbing wavelengths. In spite of the apparent similarity between the

  17. Extreme charge-trapping by pixels in Hubble's ACS/WFC detectors

    NASA Astrophysics Data System (ADS)

    Ryon, Jenna E.; Grogin, Norman A.; ACS Team

    2017-06-01

    We investigate the properties of sink pixels in the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) detector. These pixels likely contain extra charge traps and therefore appear anomalously low in images with relatively high backgrounds. We identify sink pixels in the average short (0.5-second) dark image from each monthly anneal cycle, which, since January 2015, have been post-flashed to a background of about 60 e-. Sink pixels can affect the pixels immediately above and below them in the same column, resulting in high downstream pixels and low trails of upstream pixels. We determine typical trail lengths for sink pixels of different depths at various background levels. We create a reference image, one for each anneal cycle since January 2015, that will be used by CALACS to flag sink pixels and the adjacent affected pixels in science images.

  18. Geometry simulation and physics with the CMS forward pixel detector

    NASA Astrophysics Data System (ADS)

    Parashar, N.

    2008-06-01

    The Forward Pixel Detector of CMS is an integral part of the Tracking system, which will play a key role in addressing the full physics potential of the collected data. It has a very complex geometry that encompasses multilayer structure of its detector modules. This presentation describes the development of geometry simulation for the Forward Pixel Detector. A new geometry package has been developed, which uses the detector description database (DDD) interface for the XML (eXtensive Markup Language) to GEANT simulation. This is necessary for digitization and GEANT4 reconstruction software for tracking. The expected physics performance is also discussed.

  19. Characterisation of individual pixel efficiency in the PILATUS II sensor

    NASA Astrophysics Data System (ADS)

    Schubert, A.; O'Keefe, G. J.; Sobott, B. A.; Kirby, N. M.; Rassool, R. P.

    2010-11-01

    Synchrotron applications such as protein crystallography and small-angle X-ray scattering (SAXS) demand precise knowledge of detector pixel efficiency for data corrections. Current techniques used to determine detector efficiency are only applicable for the specific set-up for which the calibration is performed. Here the effect of comparator thresholding on pixel efficiency for PILATUS is presented for standard amplifier and shaper gain settings, allowing users to make necessary corrections to their intensity data for various threshold settings without requiring repeated empirical calibrations. A three-dimensional TCAD simulation of the sensor is also presented and is used to confirm the experimental result.

  20. Mapping Pixel Windows To Vectors For Parallel Processing

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.

    1996-01-01

    Mapping performed by matrices of transistor switches. Arrays of transistor switches devised for use in forming simultaneous connections from square subarray (window) of n x n pixels within electronic imaging device containing np x np array of pixels to linear array of n(sup2) input terminals of electronic neural network or other parallel-processing circuit. Method helps to realize potential for rapidity in parallel processing for such applications as enhancement of images and recognition of patterns. In providing simultaneous connections, overcomes timing bottleneck or older multiplexing, serial-switching, and sample-and-hold methods.

  1. CMOS VLSI Active-Pixel Sensor for Tracking

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata; Sun, Chao; Yang, Guang; Heynssens, Julie

    2004-01-01

    An architecture for a proposed active-pixel sensor (APS) and a design to implement the architecture in a complementary metal oxide semiconductor (CMOS) very-large-scale integrated (VLSI) circuit provide for some advanced features that are expected to be especially desirable for tracking pointlike features of stars. The architecture would also make this APS suitable for robotic- vision and general pointing and tracking applications. CMOS imagers in general are well suited for pointing and tracking because they can be configured for random access to selected pixels and to provide readout from windows of interest within their fields of view. However, until now, the architectures of CMOS imagers have not supported multiwindow operation or low-noise data collection. Moreover, smearing and motion artifacts in collected images have made prior CMOS imagers unsuitable for tracking applications. The proposed CMOS imager (see figure) would include an array of 1,024 by 1,024 pixels containing high-performance photodiode-based APS circuitry. The pixel pitch would be 9 m. The operations of the pixel circuits would be sequenced and otherwise controlled by an on-chip timing and control block, which would enable the collection of image data, during a single frame period, from either the full frame (that is, all 1,024 1,024 pixels) or from within as many as 8 different arbitrarily placed windows as large as 8 by 8 pixels each. A typical prior CMOS APS operates in a row-at-a-time ( grolling-shutter h) readout mode, which gives rise to exposure skew. In contrast, the proposed APS would operate in a sample-first/readlater mode, suppressing rolling-shutter effects. In this mode, the analog readout signals from the pixels corresponding to the windows of the interest (which windows, in the star-tracking application, would presumably contain guide stars) would be sampled rapidly by routing them through a programmable diagonal switch array to an on-chip parallel analog memory array. The

  2. Highly Reflective Multi-stable Electrofluidic Display Pixels

    NASA Astrophysics Data System (ADS)

    Yang, Shu

    Electronic papers (E-papers) refer to the displays that mimic the appearance of printed papers, but still owning the features of conventional electronic displays, such as the abilities of browsing websites and playing videos. The motivation of creating paper-like displays is inspired by the truths that reading on a paper caused least eye fatigue due to the paper's reflective and light diffusive nature, and, unlike the existing commercial displays, there is no cost of any form of energy for sustaining the displayed image. To achieve the equivalent visual effect of a paper print, an ideal E-paper has to be a highly reflective with good contrast ratio and full-color capability. To sustain the image with zero power consumption, the display pixels need to be bistable, which means the "on" and "off" states are both lowest energy states. Pixel can change its state only when sufficient external energy is given. There are many emerging technologies competing to demonstrate the first ideal E-paper device. However, none is able to achieve satisfactory visual effect, bistability and video speed at the same time. Challenges come from either the inherent physical/chemical properties or the fabrication process. Electrofluidic display is one of the most promising E-paper technologies. It has successfully demonstrated high reflectivity, brilliant color and video speed operation by moving colored pigment dispersion between visible and invisible places with electrowetting force. However, the pixel design did not allow the image bistability. Presented in this dissertation are the multi-stable electrofluidic display pixels that are able to sustain grayscale levels without any power consumption, while keeping the favorable features of the previous generation electrofluidic display. The pixel design, fabrication method using multiple layer dry film photoresist lamination, and physical/optical characterizations are discussed in details. Based on the pixel structure, the preliminary

  3. Pixel multichip module design for a high energy physics experiment

    SciTech Connect

    Guilherme Cardoso et al.

    2003-11-05

    At Fermilab, a pixel detector multichip module is being developed for the BTeV experiment. The module is composed of three layers. The lowest layer is formed by the readout integrated circuits (ICs). The back of the ICs is in thermal contact with the supporting structure, while the top is flip-chip bump-bonded to the pixel sensor. A low mass flex-circuit interconnect is glued on the top of this assembly, and the readout IC pads are wire-bounded to the circuit. This paper presents recent results on the development of a multichip module prototype and summarizes its performance characteristics.

  4. Development of a high density pixel multichip module at Fermilab

    SciTech Connect

    Sergio Zimmermann et al.

    2001-09-11

    At Fermilab, a pixel detector multichip module is being developed for the BTeV experiment. The module is composed of three layers. The lowest layer is formed by the readout integrated circuits (ICs). The back of the ICs is in thermal contact with the supporting structure, while the top is flip-chip bump-bonded to the pixel sensor. A low mass flex-circuit interconnect is glued on the top of this assembly, and the readout IC pads are wire-bounded to the circuit. This paper presents recent results on the development of a multichip module prototype and summarizes its performance characteristics.

  5. The BTeV pixel and microstrip detector

    SciTech Connect

    Simon W Kwan

    2003-06-04

    The BTeV pixel detector is one of the most crucial elements in the BTeV experiment. While the pixel detector is technically challenging, we have made great progress towards identifying viable solutions for individual components of the system. The forward silicon tracker is based on more mature technology and its design has benefited from the experience of other experiments. Nevertheless, we have started an R&D program on the forward silicon tracker and first results are expected some time next year.

  6. Pixel resolution control in numerical reconstruction of digital holography.

    PubMed

    Yu, Lingfeng; Kim, Myung K

    2006-04-01

    A new method for resolution control in numerical reconstruction of digital holography is proposed. The wave field on a tilted or vertical plane can be reconstructed without being subject to the minimum object-to-hologram distance requirement, and the pixel resolution can be easily controlled by adjusting the position of a transitional plane. The proposed method solves the problem of pixel resolution control for small object-to-hologram distances and is especially useful for multicolor, multiwavelength digital holography and metrological applications. Experimental results are presented to verify the idea.

  7. SLHC upgrade plans for the ATLAS pixel detector

    NASA Astrophysics Data System (ADS)

    Šícho, Petr

    2009-08-01

    The ATLAS pixel detector is an 80 million channels silicon tracking system designed to detect charged tracks and secondary vertices with very high precision. An upgrade of the ATLAS pixel detector is presently being considered, enabling to cope with higher luminosity at Super Large Hadron Collider (SLHC). The increased luminosity leads to extremely high radiation doses in the innermost region of the ATLAS tracker. Options considered for a new detector are discussed, as well as some important R&D activities, such as investigations towards novel detector geometries and novel processes.

  8. Tomography for SST-1 tokamak with pixel method

    SciTech Connect

    Chattopadhyay, Asim Kumar; Anand, Arun; Rao, C.V.S.

    2005-06-15

    A soft x-ray tomography code by pixel method has been prepared and tested with simulated data for the five array and seven array system of the SST-1 tokamak. A relatively small number of detectors have been used to obtain a partial view of the highly noncircular plasma in a poloidal plane produced in a machine of limited access like SST-1 by optimizing the pixel size and array positions. Tomographic inversions are done using linear regularization, minimum Fisher information and maximum entropy methods. Singular value decomposition method has been used for the identification of magnetohydrodynamic modes by analyzing inversion results.

  9. Mapping Pixel Windows To Vectors For Parallel Processing

    NASA Technical Reports Server (NTRS)

    Duong, Tuan A.

    1996-01-01

    Mapping performed by matrices of transistor switches. Arrays of transistor switches devised for use in forming simultaneous connections from square subarray (window) of n x n pixels within electronic imaging device containing np x np array of pixels to linear array of n(sup2) input terminals of electronic neural network or other parallel-processing circuit. Method helps to realize potential for rapidity in parallel processing for such applications as enhancement of images and recognition of patterns. In providing simultaneous connections, overcomes timing bottleneck or older multiplexing, serial-switching, and sample-and-hold methods.

  10. Delineation of sub-pixel level sedimentary litho-contacts by super resolution mapping of Landsat image

    NASA Astrophysics Data System (ADS)

    Shanmuga Priyaa, S.; Sanjeevi, S.

    2014-12-01

    To delineate the geological formation at the surface, satellite image classification approaches are often preferred. This study aims to produce a super resolved map with better delineation of the litho-contacts from the medium resolution Landsat image. Conventionally used per-pixel classification provides an output map at the same resolution of the satellite image, while the super resolved map provides the high resolution output map using the medium resolution image. In this study, four test sites are considered for delineating different litho-contacts using super resolution mapping approach in Cuddalore district, southern India. The test sites consists of charnockite, fissile hornblende-biotite gneiss, marine sandstone and sandstone with clay, limestone with calcareous shale and clay, clay with limestone bands/lenses, mio-pliocene and quaternary argillaceous and calcareous sandstone, fluvial and fluviomarine formations. This work compares the per-pixel, super resolved output derived from linear spectral unmixing (LSU) based HNN and spectral angle mapper (SAM) based HNN approaches. The super resolution mapping approach was performed on the medium resolution (30 m) Landsat image to obtain the litho-contact maps and the results are compared with the existing maps and observations from field visits. The results showed improved accuracy (90.92%) of the map prepared by the SAM based super resolution approach compared to the LSU based super resolution approach (90.14%) and the maximum likelihood classification approach (83.74%). Such an improved accuracy of the super resolved map (6 m resolution) is due to the fact that the lithological mapping is done not merely at the resolution of the image, but at the sub-pixel level. Hence, it is inferred that super resolution mapping applied to multispectral images may be preferred for mapping lithounits and litho-contacts than the conventional per-pixel and sub-pixel image classification methods.

  11. ATLAS Pixel Detector ROD card from IBL towards Layers 2 and 1

    NASA Astrophysics Data System (ADS)

    Balbi, G.; Falchieri, D.; Gabrielli, A.; Lama, L.; Giangiacomi, N.; Travaglini, R.

    2016-01-01

    The incoming and future upgrades of LHC will require better performance by the data acquisition system, especially in terms of throughput due to the higher luminosity that is expected. For this reason, during the first shutdown of the LHC collider in 2013/14, the ATLAS Pixel Detector has been equipped with a fourth layer— the Insertable B-Layer or IBL—located at a radius smaller than the present three layers. To read out the new layer of pixels, with a smaller pixel size with respect to the other outer layers, a front end ASIC (FE-I4) was designed as well as a new off-detector read-out chain. The latter, accordingly to the structure of the other layers of pixels, is composed mainly of two 9U-VME read-out off-detector cards called the Back-Of-Crate (BOC) and Read-Out Driver (ROD). The ROD is used for data and event formatting and for configuration and control of the overall read-out electronics. After some prototyping samples were completed, a pre-production batch of 5 ROD cards was delivered with the final layout. Another production of 15 ROD cards was done in Fall 2013, and commissioning was completed in 2014. Altogether 14 cards are necessary for the 14 staves of the IBL detector, one additional card is required by the Diamond Beam Monitor (DBM), and additional spare ROD cards were produced for a total initial batch of 20 boards. This paper describes some integration tests that were performed and our plan to install the new DAQ chain for the layer 2, which is the outermost, and layer 1, which is external to the B-layer. This latter is the only layer that will not be upgraded to a higher readout speed. Rather, it will be switched off in the near future as it has too many damaged sensors that were not possible to rework. To do that, slices of the IBL read-out chain have been instrumented, and ROD performance is verified on a test bench mimicking a small-sized final setup. Thus, this contribution reports also how the adoption of the IBL ROD for ATLAS Pixel

  12. Fully depleted CMOS pixel sensor development and potential applications

    SciTech Connect

    Baudot, J.; Kachel, M.

    2015-07-01

    CMOS pixel sensors are often opposed to hybrid pixel sensors due to their very different sensitive layer. In standard CMOS imaging processes, a thin (about 20 μm) low resistivity epitaxial layer acts as the sensitive volume and charge collection is mostly driven by thermal agitation. In contrast, the so-called hybrid pixel technology exploits a thick (typically 300 μm) silicon sensor with high resistivity allowing for the depletion of this volume, hence charges drift toward collecting electrodes. But this difference is fading away with the recent availability of some CMOS imaging processes based on a relatively thick (about 50 μm) high resistivity epitaxial layer which allows for full depletion. This evolution extents the range of applications for CMOS pixel sensors where their known assets, high sensitivity and granularity combined with embedded signal treatment, could potentially foster breakthrough in detection performances for specific scientific instruments. One such domain is the Xray detection for soft energies, typically below 10 keV, where the thin sensitive layer was previously severely impeding CMOS sensor usage. Another application becoming realistic for CMOS sensors, is the detection in environment with a high fluence of non-ionizing radiation, such as hadron colliders. However, when considering highly demanding applications, it is still to be proven that micro-circuits required to uniformly deplete the sensor at the pixel level, do not mitigate the sensitivity and efficiency required. Prototype sensors in two different technologies with resistivity higher than 1 kΩ, sensitive layer between 40 and 50 μm and featuring pixel pitch in the range 25 to 50 μm, have been designed and fabricated. Various biasing architectures were adopted to reach full depletion with only a few volts. Laboratory investigations with three types of sources (X-rays, β-rays and infrared light) demonstrated the validity of the approach with respect to depletion, keeping a

  13. Improving Kepler Pipeline Sensitivity with Pixel Response Function Photometry.

    NASA Astrophysics Data System (ADS)

    Morris, Robert L.; Bryson, Steve; Jenkins, Jon Michael; Smith, Jeffrey C

    2014-06-01

    We present the results of our investigation into the feasibility and expected benefits of implementing PRF-fitting photometry in the Kepler Science Processing Pipeline. The Kepler Pixel Response Function (PRF) describes the expected system response to a point source at infinity and includes the effects of the optical point spread function, the CCD detector responsivity function, and spacecraft pointing jitter. Planet detection in the Kepler pipeline is currently based on simple aperture photometry (SAP), which is most effective when applied to uncrowded bright stars. Its effectiveness diminishes rapidly as target brightness decreases relative to the effects of noise sources such as detector electronics, background stars, and image motion. In contrast, PRF photometry is based on fitting an explicit model of image formation to the data and naturally accounts for image motion and contributions of background stars. The key to obtaining high-quality photometry from PRF fitting is a high-quality model of the system's PRF, while the key to efficiently processing the large number of Kepler targets is an accurate catalog and accurate mapping of celestial coordinates onto the focal plane. If the CCD coordinates of stellar centroids are known a priori then the problem of PRF fitting becomes linear. A model of the Kepler PRF was constructed at the time of spacecraft commissioning by fitting piecewise polynomial surfaces to data from dithered full frame images. While this model accurately captured the initial state of the system, the PRF has evolved dynamically since then and has been seen to deviate significantly from the initial (static) model. We construct a dynamic PRF model which is then used to recover photometry for all targets of interest. Both simulation tests and results from Kepler flight data demonstrate the effectiveness of our approach. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA’s Science

  14. Modelling and 3D optimisation of CdTe pixels detector array geometry - Extension to small pixels

    NASA Astrophysics Data System (ADS)

    Zumbiehl, A.; Hage-Ali, M.; Fougeres, P.; Koebel, J. M.; Regal, R.; Rit, C.; Ayoub, M.; Siffert, P.

    2001-08-01

    CdTe and CdZnTe pixel detectors offer great interest for many applications, especially for medical and industrial imaging. Up to now, the material, generally, used and investigated for pixel arrays was CZT (Hamel et al., IEEE Trans. Nucl. Sci. 43 (3) (1996) 1422; Barrett et al., Phys. Rev. Lett. 75 (1) (1995) 156; Bennett et al., Nucl. Instr. and Meth. A 392 (1997) 260; Eskin et al., J. Appl. Phys. 85 (2) (1999) 647; Brunett et al., J. Appl. Phys. 86 (7) (1999) 3926; Luke, Nucl. Instr. and Meth. A 380 (1996) 232), but cadmium telluride can also be an appropriate choice, as shown here. However, we clearly demonstrate here that the optimal pixel configuration is highly dependent on the electrical transport properties of the material. Depending on the field of primary interest, either energy resolution or counting rate efficiency in the photopeak, the geometry for each case has to be optimised. For that purpose, we have developed a calculation of the signal induced onto the pixel. Two distinct parts are used: after showing our approach for the weighting potential calculation, we present our results performed by a "pseudo-Monte Carlo" simulation. Results are supported by a few experimental comparisons. We argue about the optimum sizes with clarifying the problems caused by too small and too large pixel sizes. The study field is chosen to be vast, i.e. pixel size to detector thickness ratios ( W/ L) of 1/8-1, and detector thickness of 1.0-8.0 mm. In addition, several electrical transport properties are used. Since efficiency is often of primary interest, thick detectors could be very attractive, which are shown to be really feasible even on CdTe.

  15. Impact of defective pixels in AMLCDs on the perception of medical images

    NASA Astrophysics Data System (ADS)

    Kimpe, Tom; Sneyders, Yuri

    2006-03-01

    With LCD displays, each pixel has its own individual transistor that controls the transmittance of that pixel. Occasionally, these individual transistors will short or alternatively malfunction, resulting in a defective pixel that always shows the same brightness. With ever increasing resolution of displays the number of defect pixels per display increases accordingly. State of the art processes are capable of producing displays with no more than one faulty transistor out of 3 million. A five Mega Pixel medical LCD panel contains 15 million individual sub pixels (3 sub pixels per pixel), each having an individual transistor. This means that a five Mega Pixel display on average will have 5 failing pixels. This paper investigates the visibility of defective pixels and analyzes the possible impact of defective pixels on the perception of medical images. JND simulations were done to study the effect of defective pixels on medical images. Our results indicate that defective LCD pixels can mask subtle features in medical images in an unexpectedly broad area around the defect and therefore may reduce the quality of diagnosis for specific high-demanding areas such as mammography. As a second contribution an innovative solution is proposed. A specialized image processing algorithm can make defective pixels completely invisible and moreover can also recover the information of the defect so that the radiologist perceives the medical image correctly. This correction algorithm has been validated with both JND simulations and psycho visual tests.

  16. Very-large-format pulse-counting UV detectors

    NASA Technical Reports Server (NTRS)

    Timothy, J. Gethyn

    1988-01-01

    Multi-anode microchannel array (MAMA) detector systems with formats of 2048 x 2048 pixels and pixel dimensions of 25 x 25 microns are being developed for use in the NASA Goddard Hubble Space Telescope Imaging Spectrograph. This paper describes the current state of development of these detector systems.

  17. iPixel: a visual content-based and semantic search engine for retrieving digitized mammograms by using collective intelligence.

    PubMed

    Alor-Hernández, Giner; Pérez-Gallardo, Yuliana; Posada-Gómez, Rubén; Cortes-Robles, Guillermo; Rodríguez-González, Alejandro; Aguilar-Laserre, Alberto A

    2012-09-01

    Nowadays, traditional search engines such as Google, Yahoo and Bing facilitate the retrieval of information in the format of images, but the results are not always useful for the users. This is mainly due to two problems: (1) the semantic keywords are not taken into consideration and (2) it is not always possible to establish a query using the image features. This issue has been covered in different domains in order to develop content-based image retrieval (CBIR) systems. The expert community has focussed their attention on the healthcare domain, where a lot of visual information for medical analysis is available. This paper provides a solution called iPixel Visual Search Engine, which involves semantics and content issues in order to search for digitized mammograms. iPixel offers the possibility of retrieving mammogram features using collective intelligence and implementing a CBIR algorithm. Our proposal compares not only features with similar semantic meaning, but also visual features. In this sense, the comparisons are made in different ways: by the number of regions per image, by maximum and minimum size of regions per image and by average intensity level of each region. iPixel Visual Search Engine supports the medical community in differential diagnoses related to the diseases of the breast. The iPixel Visual Search Engine has been validated by experts in the healthcare domain, such as radiologists, in addition to experts in digital image analysis.

  18. CMOS monolithic active pixel sensors for high energy physics

    NASA Astrophysics Data System (ADS)

    Snoeys, W.

    2014-11-01

    Monolithic pixel detectors integrating sensor matrix and readout in one piece of silicon are only now starting to make their way into high energy physics. Two major requirements are radiation tolerance and low power consumption. For the most extreme radiation levels, signal charge has to be collected by drift from a depletion layer onto a designated collection electrode without losing the signal charge elsewhere in the in-pixel circuit. Low power consumption requires an optimization of Q/C, the ratio of the collected signal charge over the input capacitance [1]. Some solutions to combine sufficient Q/C and collection by drift require exotic fabrication steps. More conventional solutions up to now require a simple in-pixel readout circuit. Both high voltage CMOS technologies and Monolithic Active Pixel Sensors (MAPS) technologies with high resistivity epitaxial layers offer high voltage diodes. The choice between the two is not fundamental but more a question of how much depletion can be reached and also of availability and cost. This paper tries to give an overview.

  19. Use of silicon pixel detectors in double electron capture experiments

    NASA Astrophysics Data System (ADS)

    Cermak, P.; Stekl, I.; Shitov, Yu A.; Mamedov, F.; Rukhadze, E. N.; Jose, J. M.; Cermak, J.; Rukhadze, N. I.; Brudanin, V. B.; Loaiza, P.

    2011-01-01

    A novel experimental approach to search for double electron capture (EC/EC) is discussed in this article. R&D for a new generation EC/EC spectrometer based on silicon pixel detectors (SPDs) has been conducted since 2009 for an upgrade of the TGV experiment. SPDs built on Timepix technology with a spectroscopic readout from each individual pixel are an effective tool to detect the 2νEC/EC signature of the two low energy X-rays hitting two separate pixels. The ability of SPDs to indentify α/β/γ particles and localize them precisely leads to effective background discrimination and thus considerable improvement of the signal-to-background ratio (S/B). A multi-SPD system, called a Silicon Pixel Telescope (SPT), is planned based on the experimental approach of the TGV calorimeter which measures thin foils of enriched EC/EC-isotope sandwiched between HPGe detectors working in coincidence mode. The sources of SPD internal background have been identified by measuring SPD radiopurity with a low-background HPGe detector as well as by long-term SPD background runs in the Modane underground laboratory (LSM, France), and results of these studies are presented.

  20. Pixel Analysis and Plasma Dynamics Characterized by Photospheric Spectral Data

    NASA Astrophysics Data System (ADS)

    Rasca, Anthony P.; Chen, James; Pevtsov, Alexei A.

    2016-05-01

    Recent observations of the photosphere using high spatial and temporal resolutions show small dynamic features at the resolving limit during emerging flux events. However, line-of-sight (LOS) magnetogram pixels only contain the net uncanceled magnetic flux, which is expected to increase for fixed regions as resolution limits improve. A new pixel dynamics method uses spectrographic images to characterize photospheric absorption line profiles by variations in line displacement, width, asymmetry, and peakedness and is applied to quiet-sun regions, active regions with no eruption, and an active region with an ongoing eruption. Using Stokes I images from SOLIS/VSM on 2012 March 13, variations in line width and peakedness of Fe I 6301.5 Å are shown to have a strong spatial and temporal relationship with an M7.9 X-ray flare originating from NOAA 11429. This relationship is observed as a flattening in the line profile as the X-ray flare approaches peak intensity and was not present in area scans of a non-eruptive active region on 2011 April 14. These results are used to estimate dynamic plasma properties on sub-pixel scales and provide both spatial and temporal information of sub-pixel activity at the photosphere. The analysis can be extended to include the full Stokes parameters and study signatures of magnetic fields and coupled plasma properties.

  1. Photovoltaic Pixels for Neural Stimulation: Circuit Models and Performance.

    PubMed

    Boinagrov, David; Lei, Xin; Goetz, Georges; Kamins, Theodore I; Mathieson, Keith; Galambos, Ludwig; Harris, James S; Palanker, Daniel

    2016-02-01

    Photovoltaic conversion of pulsed light into pulsed electric current enables optically-activated neural stimulation with miniature wireless implants. In photovoltaic retinal prostheses, patterns of near-infrared light projected from video goggles onto subretinal arrays of photovoltaic pixels are converted into patterns of current to stimulate the inner retinal neurons. We describe a model of these devices and evaluate the performance of photovoltaic circuits, including the electrode-electrolyte interface. Characteristics of the electrodes measured in saline with various voltages, pulse durations, and polarities were modeled as voltage-dependent capacitances and Faradaic resistances. The resulting mathematical model of the circuit yielded dynamics of the electric current generated by the photovoltaic pixels illuminated by pulsed light. Voltages measured in saline with a pipette electrode above the pixel closely matched results of the model. Using the circuit model, our pixel design was optimized for maximum charge injection under various lighting conditions and for different stimulation thresholds. To speed discharge of the electrodes between the pulses of light, a shunt resistor was introduced and optimized for high frequency stimulation.

  2. High responsivity CMOS imager pixel implemented in SOI technology

    NASA Technical Reports Server (NTRS)

    Zheng, X.; Wrigley, C.; Yang, G.; Pain, B.

    2000-01-01

    Availability of mature sub-micron CMOS technology and the advent of the new low noise active pixel sensor (APS) concept have enabled the development of low power, miniature, single-chip, CMOS digital imagers in the decade of the 1990's.

  3. Optimization of Focusing by Strip and Pixel Arrays

    SciTech Connect

    Burke, G J; White, D A; Thompson, C A

    2005-06-30

    Professor Kevin Webb and students at Purdue University have demonstrated the design of conducting strip and pixel arrays for focusing electromagnetic waves [1, 2]. Their key point was to design structures to focus waves in the near field using full wave modeling and optimization methods for design. Their designs included arrays of conducting strips optimized with a downhill search algorithm and arrays of conducting and dielectric pixels optimized with the iterative direct binary search method. They used a finite element code for modeling. This report documents our attempts to duplicate and verify their results. We have modeled 2D conducting strips and both conducting and dielectric pixel arrays with moment method and FDTD codes to compare with Webb's results. New designs for strip arrays were developed with optimization by the downhill simplex method with simulated annealing. Strip arrays were optimized to focus an incident plane wave at a point or at two separated points and to switch between focusing points with a change in frequency. We also tried putting a line current source at the focus point for the plane wave to see how it would work as a directive antenna. We have not tried optimizing the conducting or dielectric pixel arrays, but modeled the structures designed by Webb with the moment method and FDTD to compare with the Purdue results.

  4. Diamond pixel modules and the ATLAS beam conditions monitor

    NASA Astrophysics Data System (ADS)

    Dobos, D.; Pernegger, Heinz; RD42 Collaboration; ATLAS Diamond Pixel Upgrade Collaboration; ATLAS Beam Conditions Monitor Collaborations

    2011-02-01

    Chemical vapor deposition diamonds are considered among possible sensor materials for the next pixel upgrade in ATLAS. Full size diamond pixel modules have been constructed to the specification of the ATLAS Pixel Detector using poly-crystalline CVD diamond sensors to develop the production techniques required for industrial production. Those modules were tested in the lab and testbeam. Additionally we will present results of diamond pixel modules using single-crystal diamonds and results of proton irradiations up to 1.8 ×10 16 protons/cm 2. The ATLAS Beam Conditions Monitors (BCM) main purpose is to protect the experiments silicon tracker from beam incidents. In total 16 1×1 cm2 500 μm thick diamond pCVD sensors are used in eight positions around the LHC interaction point. They perform time difference measurements with sub nanosecond resolution to distinguish between particles from a collision and spray particles from a beam incident; an abundance of the latter can lead the BCM to provoke an abort of LHC beam. The BCM diamond detector modules, their readout system and the algorithms used to detect beam incidents are described. Results of the BCM operation with circulating LHC beams and its commissioning with first LHC collisions are reported.

  5. Self-adjusting threshold mechanism for pixel detectors

    NASA Astrophysics Data System (ADS)

    Heim, Timon; Garcia-Sciveres, Maurice

    2017-09-01

    Readout chips of hybrid pixel detectors use a low power amplifier and threshold discrimination to process charge deposited in semiconductor sensors. Due to transistor mismatch each pixel circuit needs to be calibrated individually to achieve response uniformity. Traditionally this is addressed by programmable threshold trimming in each pixel, but requires robustness against radiation effects, temperature, and time. In this paper a self-adjusting threshold mechanism is presented, which corrects the threshold for both spatial inequality and time variation and maintains a constant response. It exploits the electrical noise as relative measure for the threshold and automatically adjust the threshold of each pixel to always achieve a uniform frequency of noise hits. A digital implementation of the method in the form of an up/down counter and combinatorial logic filter is presented. The behavior of this circuit has been simulated to evaluate its performance and compare it to traditional calibration results. The simulation results show that this mechanism can perform equally well, but eliminates instability over time and is immune to single event upsets.

  6. Gauss-Legendre Sky Pixelization (glesp) for CMB Maps

    NASA Astrophysics Data System (ADS)

    Doroshkevich, A. G.; Naselsky, P. D.; Verkhodanov, O. V.; Novikov, D. I.; Turchaninov, V. I.; Novikov, I. D.; Christensen, P. R.; Chiang, L.-Y.

    A new scheme of sky pixelization is developed for CMB maps. The scheme is based on the Gauss-Legendre polynomials zeros and allows one to create strict orthogonal expansion of the map. A corresponding code has been implemented and comparison with other methods has been done.

  7. Electron imaging with Medipix2 hybrid pixel detector.

    PubMed

    McMullan, G; Cattermole, D M; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 microm x 55 microm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 microm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach approximately 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach approximately 35% of that expected for a perfect detector (4/pi(2)). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/pi). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected values for the MTF and DQE as a function of the threshold energy. The good agreement between theory and experiment allows suggestions for further improvements to be made with confidence. The present detector is already very useful for experiments that require a high DQE at very low doses.

  8. Thin Film on CMOS Active Pixel Sensor for Space Applications.

    PubMed

    Schulze Spuentrup, Jan Dirk; Burghartz, Joachim N; Graf, Heinz-Gerd; Harendt, Christine; Hutter, Franz; Nicke, Markus; Schmidt, Uwe; Schubert, Markus; Sterzel, Juergen

    2008-10-13

    A 664 x 664 element Active Pixel image Sensor (APS) with integrated analog signal processing, full frame synchronous shutter and random access for applications in star sensors is presented and discussed. A thick vertical diode array in Thin Film on CMOS (TFC) technology is explored to achieve radiation hardness and maximum fill factor.

  9. Sub-pixel localization of highways in AVIRIS images

    NASA Technical Reports Server (NTRS)

    Salu, Yehuda

    1995-01-01

    Roads and highways show up clearly in many bands of AVIRIS images. A typical lane in the U.S. is 12 feet wide, and the total width of a four lane highway, including 18 feet of paved shoulders, is 19.8 m. Such a highway will cover only a portion of any 20x20 m AVIRIS pixel that it traverses. The other portion of these pixels wil be usually covered by vegetation. An interesting problem is to precisely determine the location of a highway within the AVIRIS pixels that it traverses. This information may be used for alignment and spatial calibration of AVIRIS images. Also, since the reflection properties of highway surfaces do not change with time, and they can be determined once and for all, such information can be of help in calculating and filtering out the atmospheric noise that contaminates AVIRIS measurements. The purpose of this report is to describe a method for sub-pixel localization of highways.

  10. Advancement in 17-micron pixel pitch uncooled focal plane arrays

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Skidmore, George; Howard, Christopher; Clarke, Elwood; Han, C. J.

    2009-05-01

    This paper provides an update of 17 micron pixel pitch uncooled microbolometer development at DRS. Since the introduction of 17 micron pitch 640x480 focal plane arrays (FPAs) in 2006, significant progress has been made in sensor performance and manufacturing processes. The FPAs are now in initial production with an FPA noise equivalent temperature difference (NETD), detector thermal time constant, and pixel operability equivalent or better than that of the current 25 micron pixel pitch production FPAs. NETD improvement was achieved without compromising detector thermal response or thermal time constant by simultaneous reduction in bolometer heat capacity and thermal conductance. In addition, the DRS unique "umbrella" microbolometer cavities were optically tuned to optimize detector radiation absorption for specific spectral band applications. The 17 micron pixel pitch FPAs are currently being considered for the next generation soldier systems such as thermal weapon sights (TWS), vehicle driver vision enhancers (DVE), digitally fused enhanced night vision goggles (DENVG) and unmanned air vehicle (UAV) surveillance sensors, because of overall thermal imaging system size, weight and power advantages.

  11. Metamaterial-based single pixel imaging system (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Padilla, Willie; Watts, Claire M.; Nadell, Christian; Montoya, John A.; Krishna, Sanjay

    2015-09-01

    Single pixel cameras are useful imaging devices where it is difficult or infeasible to fashion focal plan arrays. For example in the Far Infrared (FIR) it is difficult to perform imaging by conventional detector arrays, owing to the cost and size of such an array. The typical single pixel camera uses a spatial light modulator (SLM) - placed in the conjugate image plane - and is used to sample various portions of the image. The spatially modulated light emerging from the SLM is then sent to a single detector where the light is condensed with suitable optics for detection. Conventional SLMs are either based on liquid crystals or digital mirror devices. As such these devices are limited in modulation speeds of order 30 kHz. Further there is little control over the type of light that is modulated. We present metamaterial based spatial light modulators which provide the ability to digitally encode images - with various measurement matrix coefficients - thus permitting high speed and fidelity imaging capability. In particular we use the Hadamard matrix and related S-matrix to encode images for single pixel imaging. Metamaterials thus permit imaging in regimes of the electromagnetic spectrum where conventional SLMs are not available. Additionally, metamaterials offer several salient features that are not available with commercial SLMs. For example, metamaterials may be used to enable hyperspectral, polarimetric, and phase sensitive imaging. We present the theory and experimental results of single pixel imaging with digital metamaterials in the far infrared and highlight the future of this exciting field.

  12. Spectral Information Retrieval for Sub-Pixel Building Edge Detection

    NASA Astrophysics Data System (ADS)

    Avbelj, J.

    2012-07-01

    Building extraction from imagery has been an active research area for decades. However, the precise building detection from hyperspectral (HSI) images solely is a less often addressed research question due to the low spatial resolution of data. The building boundaries are usually represented by spectrally mixed pixels, and classical edge detector algorithms fail to detect borders with sufficient completeness. The idea of the proposed method is to use fraction of materials in mixed pixels to derive weights for adjusting building boundaries. The building regions are detected using seeded region growing and merging in a HSI image; for the initial seed point selection the digital surface model (DSM) is used. Prior to region growing, the seeds are statistically tested for outliers on the basis of their spectral characteristics. Then, the border pixels of building regions are compared in spectrum to the seed points by calculating spectral dissimilarity. From this spectral dissimilarity the weights for weighted and constrained least squares (LS) adjustment are derived. We used the Spectral Angle Mapper (SAM) for spectral similarity measure, but the proposed boundary estimation method could benefit from soft classification or spectral unmixing results. The method was tested on a HSI image with spatial resolution of 4 m, and buildings of rectangular shape. The importance of constraints to the relations between building parts, e.g. perpendicularity is shown on example with a building with inner yards. The adjusted building boundaries are compared to the laser DSM, and have a relative accuracy of boundaries 1/4 of a pixel.

  13. Fourier transform demodulation of pixelated phase-masked interferograms.

    PubMed

    Servin, M; Estrada, J C; Medina, O

    2010-07-19

    Recently a new type of spatial phase shifting interferometer was proposed that uses a phase-mask over the camera's pixels. This new interferometer allows one to phase modulate each pixel independently by setting the angle of a linear polarizer built in contact over the camera's CCD. In this way neighbor pixels may have any desired (however fixed) phase shift without cross taking. The standard manufacturing of these interferometers uses a 2x2 array with phase-shifts of 0, pi/2, pi, and 3 pi/2 radians. This 2x2 array is tiled all over the video camera's CCD. In this paper we propose a new way to phase demodulate these phase-masked interferograms using the squeezing phase-shifting technique. A notable advantage of this squeezing technique is that it allows one the use of Fourier interferometry wiping out the detuning error that most phase shifting algorithms suffers. Finally we suggest the use of an alternative phase-mask to phase modulate the camera's pixels using a linear spatial carrier along a given axis.

  14. Harmonics rejection in pixelated interferograms using spatio-temporal demodulation.

    PubMed

    Padilla, J M; Servin, M; Estrada, J C

    2011-09-26

    Pixelated phase-mask interferograms have become an industry standard in spatial phase-shifting interferometry. These pixelated interferograms allow full wavefront encoding using a single interferogram. This allows the study of fast dynamic events in hostile mechanical environments. Recently an error-free demodulation method for ideal pixelated interferograms was proposed. However, non-ideal conditions in interferometry may arise due to non-linear response of the CCD camera, multiple light paths in the interferometer, etc. These conditions generate non-sinusoidal fringes containing harmonics which degrade the phase estimation. Here we show that two-dimensional Fourier demodulation of pixelated interferograms rejects most harmonics except the complex ones at {-3(rd), +5(th), -7(th), +9(th), -11(th),…}. We propose temporal phase-shifting to remove these remaining harmonics. In particular, a 2-step phase-shifting algorithm is used to eliminate the -3(rd) and +5(th) complex harmonics, while a 3-step one is used to remove the -3(rd), +5<(th), -7(th) and +9(th) complex harmonics.

  15. Detection and compensation of bad pixel for CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Xu, Youqing; Yu, Shengsheng; Zhou, Jingli; Fang, Zuyuan

    2000-05-01

    This paper presents a detailed analysis of the occurring reason and features of bad pixels in CMOS image sensor. Detect and compensate algorithms have also bee introduced. Experimental result show that the algorithms are efficiently when they are applied on CH5001 produced by Chrontel Inc.

  16. Phase 1 upgrade of the CMS pixel detector

    NASA Astrophysics Data System (ADS)

    Saha, Anirban

    2017-02-01

    The pixel tracker of the Compact Muon Solenoid (CMS) experiment is the innermost sub-detector, located close to the collision point, and is used for reconstruction of the tracks and vertices of charged particles. The present pixel detector was designed to work efficiently with the maximum instantaneous luminosity of 1 × 1034 cm‑2 s‑1. In 2017 the Large Hadron Collider (LHC) is expected to deliver a peak luminosity reaching up to 2 × 1034 cm‑2 s‑1, increasing the mean number of primary vertices to 50. Due to the radiation damage and significant data losses due to high occupancy in the readout chip of the pixel detector, the present system must be replaced by a new one in an extended end-of-year shutdown during winter 2016/2017 in order to maintain the excellent tracking and other physics performances. The main new features of the upgraded pixel detector are a ultra-light mechanical design with four barrel layers and three end-cap disks, digital readout chip with higher rate capability and a new cooling system. In this document, we discuss the motivations for the upgrade, the design, and technological choices made, the status of the construction of the new detector and the future plans for the installation and commissioning.

  17. The pixel tracking telescope at the Fermilab Test Beam Facility

    DOE PAGES

    Kwan, Simon; Lei, CM; Menasce, Dario; ...

    2016-03-01

    An all silicon pixel telescope has been assembled and used at the Fermilab Test Beam Facility (FTBF) since 2009 to provide precise tracking information for different test beam experiments with a wide range of Detectors Under Test (DUTs) requiring high resolution measurement of the track impact point. The telescope is based on CMS pixel modules left over from the CMS forward pixel production. Eight planes are arranged to achieve a resolution of less than 8 μm on the 120 GeV proton beam transverse coordinate at the DUT position. In order to achieve such resolution with 100 × 150 μm2 pixelmore » cells, the planes were tilted to 25 degrees to maximize charge sharing between pixels. Crucial for obtaining this performance is the alignment software, called Monicelli, specifically designed and optimized for this system. This paper will describe the telescope hardware, the data acquisition system and the alignment software constituting this particle tracking system for test beam users.« less

  18. The NUC and blind pixel eliminating in the DTDI application

    NASA Astrophysics Data System (ADS)

    Su, Xiao Feng; Chen, Fan Sheng; Pan, Sheng Da; Gong, Xue Yi; Dong, Yu Cui

    2013-12-01

    AS infrared CMOS Digital TDI (Time Delay and integrate) has a simple structure, excellent performance and flexible operation, it has been used in more and more applications. Because of the limitation of the Production process level, the plane array of the infrared detector has a large NU (non-uniformity) and a certain blind pixel rate. Both of the two will raise the noise and lead to the TDI works not very well. In this paper, for the impact of the system performance, the most important elements are analyzed, which are the NU of the optical system, the NU of the Plane array and the blind pixel in the Plane array. Here a reasonable algorithm which considers the background removal and the linear response model of the infrared detector is used to do the NUC (Non-uniformity correction) process, when the infrared detector array is used as a Digital TDI. In order to eliminate the impact of the blind pixel, the concept of surplus pixel method is introduced in, through the method, the SNR (signal to noise ratio) can be improved and the spatial and temporal resolution will not be changed. Finally we use a MWIR (Medium Ware Infrared) detector to do the experiment and the result proves the effectiveness of the method.

  19. Overview of the BTeV Pixel Detector

    SciTech Connect

    Jeffrey A Appel

    2002-12-10

    BTeV is a new Fermilab beauty and charm experiment designed to operate in the CZero region of the Tevatron collider. Critical to the success of BTeV is its pixel detector. The unique features of this pixel detector include its proximity to the beam, its operation with a beam crossing time of 132 ns, and the need for the detector information to be read out quickly enough to be used for the lowest level trigger. This talk presents an overview of the pixel detector design, giving the motivations for the technical choices made. The status of the current R&D on detector components is also reviewed. Additional Pixel 2002 talks on the BTeV pixel detector are given by Dave Christian[1], Mayling Wong[2], and Sergio Zimmermann[3]. Table 1 gives a selection of pixel detector parameters for the ALICE, ATLAS, BTeV, and CMS experiments. Comparing the progression of this table, which I have been updating for the last several years, has shown a convergence of specifications. Nevertheless, significant differences endure. The BTeV data-driven readout, horizontal and vertical position resolution better than 9 {micro}m with the {+-} 300 mr forward acceptance, and positioning in vacuum and as close as 6 mm from the circulating beams remain unique. These features are driven by the physics goals of the BTeV experiment. Table 2 demonstrates that the vertex trigger performance made possible by these features is requisite for a very large fraction of the B meson decay physics which is so central to the motivation for BTeV. For most of the physics quantities of interest listed in the table, the vertex trigger is essential. The performance of the BTeV pixel detector may be summarized by looking at particular physics examples; e.g., the B{sub s} meson decay B{sub s} {yields} D{sub s}{sup -} K{sup +}. For that decay, studies using GEANT3 simulations provide quantitative measures of performance. For example, the separation between the B{sub s} decay point and the primary proton

  20. Remote Sensing Classification Uncertainty: Validating Probabilistic Pixel Level Classification

    NASA Astrophysics Data System (ADS)

    Vrettas, Michail; Cornford, Dan; Bastin, Lucy; Pons, Xavier; Sevillano, Eva; Moré, Gerard; Serra, Pere; Ninyerola, Miquel

    2013-04-01

    There already exists an extensive literature on classification of remotely sensed imagery, and indeed classification more widely, that considers a wide range of probabilistic and non-probabilistic classification methodologies. Although for many probabilistic classification methodologies posterior class probabilities are produced per pixel (observation) these are often not communicated at the pixel level, and typically not validated at the pixel level. Most often the probabilistic classification in converted into a hard classification (of the most probable class) and the accuracy of the resulting classification is reported in terms of a global confusion matrix, or some score derived from this. For applications where classification accuracy is spatially variable and where pixel level estimates of uncertainty can be meaningfully exploited in workflows that propagate uncertainty validating and communicating the pixel level uncertainty opens opportunities for more refined and accountable modelling. In this work we describe our recent work applying and validation of a range of probabilistic classifiers. Using a multi-temporal Landsat data set of the Ebro Delta in Catalonia, which has been carefully radiometrically and geometrically corrected, we present a range of Bayesian classifiers from simple Bayesian linear discriminant analysis to a complex variational Gaussian process based classifier. Field study derived labelled data, classified into 8 classes, which primarily consider land use and the degree of flooding in what is a rice growing region, are used to train the pixel level classifiers. Our focus is not so much on the classification accuracy, but rather the validation of the probabilistic classification made by all methods. We present a range of validation plots and scores, many of which are used for probabilistic weather forecast verification, but are new to remote sensing classification including of course the standard measures of misclassification, but also

  1. Sub-pixel Area Calculation Methods for Estimating Irrigated Areas.

    PubMed

    Thenkabailc, Prasad S; Biradar, Chandrashekar M; Noojipady, Praveen; Cai, Xueliang; Dheeravath, Venkateswarlu; Li, Yuanjie; Velpuri, Manohar; Gumma, Muralikrishna; Pandey, Suraj

    2007-10-31

    The goal of this paper was to develop and demonstrate practical methods forcomputing sub-pixel areas (SPAs) from coarse-resolution satellite sensor data. Themethods were tested and verified using: (a) global irrigated area map (GIAM) at 10-kmresolution based, primarily, on AVHRR data, and (b) irrigated area map for India at 500-mbased, primarily, on MODIS data. The sub-pixel irrigated areas (SPIAs) from coarse-resolution satellite sensor data were estimated by multiplying the full pixel irrigated areas(FPIAs) with irrigated area fractions (IAFs). Three methods were presented for IAFcomputation: (a) Google Earth Estimate (IAF-GEE); (b) High resolution imagery (IAF-HRI); and (c) Sub-pixel de-composition technique (IAF-SPDT). The IAF-GEE involvedthe use of "zoom-in-views" of sub-meter to 4-meter very high resolution imagery (VHRI)from Google Earth and helped determine total area available for irrigation (TAAI) or netirrigated areas that does not consider intensity or seasonality of irrigation. The IAF-HRI isa well known method that uses finer-resolution data to determine SPAs of the coarser-resolution imagery. The IAF-SPDT is a unique and innovative method wherein SPAs aredetermined based on the precise location of every pixel of a class in 2-dimensionalbrightness-greenness-wetness (BGW) feature-space plot of red band versus near-infraredband spectral reflectivity. The SPIAs computed using IAF-SPDT for the GIAM was within2 % of the SPIA computed using well known IAF-HRI. Further the fractions from the 2 methods were significantly correlated. The IAF-HRI and IAF-SPDT help to determine annualized or gross irrigated areas (AIA) that does consider intensity or seasonality (e.g., sum of areas from season 1, season 2, and continuous year-round crops). The national census based irrigated areas for the top 40 irrigated nations (which covers about 90% of global irrigation) was significantly better related (and had lesser uncertainties and errors) when compared to SPIAs than

  2. Minimum Variance Approaches to Ultrasound Pixel-Based Beamforming.

    PubMed

    Nguyen, Nghia Q; Prager, Richard W

    2017-02-01

    We analyze the principles underlying minimum variance distortionless response (MVDR) beamforming in order to integrate it into a pixel-based algorithm. There is a challenge posed by the low echo signal-to-noise ratio (eSNR) when calculating beamformer contributions at pixels far away from the beam centreline. Together with the well-known scarcity of samples for covariance matrix estimation, this reduces the beamformer performance and degrades the image quality. To address this challenge, we implement the MVDR algorithm in two different ways. First, we develop the conventional minimum variance pixel-based (MVPB) beamformer that performs the MVDR after the pixel-based superposition step. This involves a combination of methods in the literature, extended over multiple transmits to increase the eSNR. Then we propose the coherent MVPB beamformer, where the MVDR is applied to data within individual transmits. Based on pressure field analysis, we develop new algorithms to improve the data alignment and matrix estimation, and hence overcome the low-eSNR issue. The methods are demonstrated on data acquired with an ultrasound open platform. The results show the coherent MVPB beamformer substantially outperforms the conventional MVPB in a series of experiments, including phantom and in vivo studies. Compared to the unified pixel-based beamformer, the newest delay-and-sum algorithm in [1], the coherent MVPB performs well on regions that conform to the diffuse scattering assumptions on which the minimum variance principles are based. It produces less good results for parts of the image that are dominated by specular reflections.

  3. Single-pixel optical imaging with compressed reference intensity patterns

    NASA Astrophysics Data System (ADS)

    Chen, Wen; Chen, Xudong

    2015-03-01

    Ghost imaging with single-pixel bucket detector has attracted more and more current attention due to its marked physical characteristics. However, in ghost imaging, a large number of reference intensity patterns are usually required for object reconstruction, hence many applications based on ghost imaging (such as tomography and optical security) may be tedious since heavy storage or transmission is requested. In this paper, we report that the compressed reference intensity patterns can be used for object recovery in computational ghost imaging (with single-pixel bucket detector), and object verification can be further conducted. Only a small portion (such as 2.0% pixels) of each reference intensity pattern is used for object reconstruction, and the recovered object is verified by using nonlinear correlation algorithm. Since statistical characteristic and speckle averaging property are inherent in ghost imaging, sidelobes or multiple peaks can be effectively suppressed or eliminated in the nonlinear correlation outputs when random pixel positions are selected from each reference intensity pattern. Since pixel positions can be randomly selected from each 2D reference intensity pattern (such as total measurements of 20000), a large key space and high flexibility can be generated when the proposed method is applied for authenticationbased cryptography. When compressive sensing is used to recover the object with a small number of measurements, the proposed strategy could still be feasible through further compressing the recorded data (i.e., reference intensity patterns) followed by object verification. It is expected that the proposed method not only compresses the recorded data and facilitates the storage or transmission, but also can build up novel capability (i.e., classical or quantum information verification) for ghost imaging.

  4. Dependent video coding using a tree representation of pixel dependencies

    NASA Astrophysics Data System (ADS)

    Amati, Luca; Valenzise, Giuseppe; Ortega, Antonio; Tubaro, Stefano

    2011-09-01

    Motion-compensated prediction induces a chain of coding dependencies between pixels in video. In principle, an optimal selection of encoding parameters (motion vectors, quantization parameters, coding modes) should take into account the whole temporal horizon of a GOP. However, in practical coding schemes, these choices are made on a frame-by-frame basis, thus with a possible loss of performance. In this paper we describe a tree-based model for pixelwise coding dependencies: each pixel in a frame is the child of a pixel in a previous reference frame. We show that some tree structures are more favorable than others from a rate-distortion perspective, e.g., because they entail a large descendance of pixels which are well predicted from a common ancestor. In those cases, a higher quality has to be assigned to pixels at the top of such trees. We promote the creation of these structures by adding a special discount term to the conventional Lagrangian cost adopted at the encoder. The proposed model can be implemented through a double-pass encoding procedure. Specifically, we devise heuristic cost functions to drive the selection of quantization parameters and of motion vectors, which can be readily implemented into a state-of-the-art H.264/AVC encoder. Our experiments demonstrate that coding efficiency is improved for video sequences with low motion, while there are no apparent gains for more complex motion. We argue that this is due to both the presence of complex encoder features not captured by the model, and to the complexity of the source to be encoded.

  5. Microlens performance limits in sub-2mum pixel CMOS image sensors.

    PubMed

    Huo, Yijie; Fesenmaier, Christian C; Catrysse, Peter B

    2010-03-15

    CMOS image sensors with smaller pixels are expected to enable digital imaging systems with better resolution. When pixel size scales below 2 mum, however, diffraction affects the optical performance of the pixel and its microlens, in particular. We present a first-principles electromagnetic analysis of microlens behavior during the lateral scaling of CMOS image sensor pixels. We establish for a three-metal-layer pixel that diffraction prevents the microlens from acting as a focusing element when pixels become smaller than 1.4 microm. This severely degrades performance for on and off-axis pixels in red, green and blue color channels. We predict that one-metal-layer or backside-illuminated pixels are required to extend the functionality of microlenses beyond the 1.4 microm pixel node.

  6. Mars Descent Imager (MARDI) on the Mars Polar Lander

    USGS Publications Warehouse

    Malin, M.C.; Caplinger, M.A.; Carr, M.H.; Squyres, S.; Thomas, P.; Veverka, J.

    2001-01-01

    The Mars Descent Imager, or MARDI, experiment on the Mars Polar Lander (MPL) consists of a camera characterized by small physical size and mass (???6 ?? 6 ?? 12 cm, including baffle; <500 gm), low power requirements (<2.5 W, including power supply losses), and high science performance (1000 x 1000 pixel, low noise). The intent of the investigation is to acquire nested images over a range of resolutions, from 8 m/pixel to better than 1 cm/pixel, during the roughly 2 min it takes the MPL to descend from 8 km to the surface under parachute and rocket-powered deceleration. Observational goals will include studies of (1) surface morphology (e.g., nature and distribution of landforms indicating past and present environmental processes); (2) local and regional geography (e.g., context for other lander instruments: precise location, detailed local relief); and (3) relationships to features seen in orbiter data. To accomplish these goals, MARDI will collect three types of images. Four small images (256 x 256 pixels) will be acquired on 0.5 s centers beginning 0.3 s before MPL's heatshield is jettisoned. Sixteen full-frame images (1024 X 1024, circularly edited) will be acquired on 5.3 s centers thereafter. Just after backshell jettison but prior to the start of powered descent, a "best final nonpowered descent image" will be acquired. Five seconds after the start of powered descent, the camera will begin acquiring images on 4 s centers. Storage for as many as ten 800 x 800 pixel images is available during terminal descent. A number of spacecraft factors are likely to impact the quality of MARDI images, including substantial motion blur resulting from large rates of attitude variation during parachute descent and substantial rocket-engine-induced vibration during powered descent. In addition, the mounting location of the camera places the exhaust plume of the hydrazine engines prominently in the field of view. Copyright 2001 by the American Geophysical Union.

  7. Pneumatic fractures in Confined Granular Media

    NASA Astrophysics Data System (ADS)

    Eriksen, Fredrik K.; Toussaint, Renaud; Jørgen Måløy, Knut; Grude Flekkøy, Eirik; Turkaya, Semih

    2016-04-01

    We will present our ongoing study of the patterns formed when air flows into a dry, non-cohesive porous medium confined in a horizontal Hele-Shaw cell. This is an optically transparent system consisting of two glass plates separated by 0.5 to 1 mm, containing a packing of dry 80 micron beads in between. The cell is rectangular and has an air-permeable boundary (blocking beads) at one short edge, while the other three edges are completely sealed. The granular medium is loosely packed against the semi-permeable boundary and fills about 80 % of the cell volume. This leaves an empty region at the sealed side, where an inlet allows us to set and maintain the air at a constant overpressure (0.1 - 2 bar). For the air trapped inside the cell to relax its overpressure it has to move through the deformable granular medium. Depending on the applied overpressure and initial density of the medium, we observe a range of different behaviors such as seepage through the pore-network with or without an initial compaction of the solid, formation of low density bubbles with rearrangement of particles, granular fingering/fracturing, and erosion inside formed channels/fractures. The experiments are recorded with a high-speed camera at a framerate of 1000 images/s and a resolution of 1024x1024 pixels. We use various image processing techniques to characterize the evolution of the air invasion patterns and the deformations in the surrounding material. The experiments are similar to deformation processes in porous media which are driven by pore fluid overpressure, such as mud volcanoes and hydraulic or pneumatic (gas-induced) fracturing, and the motivation is to increase the understanding of such processes by optical observations. In addition, this setup is an experimental version of the numerical models analyzed by Niebling et al. [1,2], and is useful for comparison with their results. In a directly related project [3], acoustic emissions from the cell plate are recorded during

  8. Land cover mapping at sub-pixel scales

    NASA Astrophysics Data System (ADS)

    Makido, Yasuyo Kato

    One of the biggest drawbacks of land cover mapping from remotely sensed images relates to spatial resolution, which determines the level of spatial details depicted in an image. Fine spatial resolution images from satellite sensors such as IKONOS and QuickBird are now available. However, these images are not suitable for large-area studies, since a single image is very small and therefore it is costly for large area studies. Much research has focused on attempting to extract land cover types at sub-pixel scale, and little research has been conducted concerning the spatial allocation of land cover types within a pixel. This study is devoted to the development of new algorithms for predicting land cover distribution using remote sensory imagery at sub-pixel level. The "pixel-swapping" optimization algorithm, which was proposed by Atkinson for predicting sub-pixel land cover distribution, is investigated in this study. Two limitations of this method, the arbitrary spatial range value and the arbitrary exponential model of spatial autocorrelation, are assessed. Various weighting functions, as alternatives to the exponential model, are evaluated in order to derive the optimum weighting function. Two different simulation models were employed to develop spatially autocorrelated binary class maps. In all tested models, Gaussian, Exponential, and IDW, the pixel swapping method improved classification accuracy compared with the initial random allocation of sub-pixels. However the results suggested that equal weight could be used to increase accuracy and sub-pixel spatial autocorrelation instead of using these more complex models of spatial structure. New algorithms for modeling the spatial distribution of multiple land cover classes at sub-pixel scales are developed and evaluated. Three methods are examined: sequential categorical swapping, simultaneous categorical swapping, and simulated annealing. These three methods are applied to classified Landsat ETM+ data that has

  9. A novel CMOS sensor with in-pixel auto-zeroed discrimination for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Degerli, Y.; Guilloux, F.; Orsini, F.

    2014-05-01

    With the aim of developing fast and granular Monolithic Active Pixels Sensors (MAPS) as new charged particle tracking detectors for high energy physics experiments, a new rolling shutter binary pixel architecture concept (RSBPix) with in-pixel correlated double sampling, amplification and discrimination is presented. The discriminator features auto-zeroing in order to compensate process-related transistor mismatches. In order to validate the pixel, a first monolithic CMOS sensor prototype, including a pixel array of 96 × 64 pixels, has been designed and fabricated in the Tower-Jazz 0.18 μm CMOS Image Sensor (CIS) process. Results of laboratory tests are presented.

  10. High throughput optoelectronic smart pixel systems using diffractive optics

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Hao

    1999-12-01

    Recent developments in digital video, multimedia technology and data networks have greatly increased the demand for high bandwidth communication channels and high throughput data processing. Electronics is particularly suited for switching, amplification and logic functions, while optics is more suitable for interconnections and communications with lower energy and crosstalk. In this research, we present the design, testing, integration and demonstration of several optoelectronic smart pixel devices and system architectures. These systems integrate electronic switching/processing capability with parallel optical interconnections to provide high throughput network communication and pipeline data processing. The Smart Pixel Array Cellular Logic processor (SPARCL) is designed in 0.8 m m CMOS and hybrid integrated with Multiple-Quantum-Well (MQW) devices for pipeline image processing. The Smart Pixel Network Interface (SAPIENT) is designed in 0.6 m m GaAs and monolithically integrated with LEDs to implement a highly parallel optical interconnection network. The Translucent Smart Pixel Array (TRANSPAR) design is implemented in two different versions. The first version, TRANSPAR-MQW, is designed in 0.5 m m CMOS and flip-chip integrated with MQW devices to provide 2-D pipeline processing and translucent networking using the Carrier- Sense-MultipleAccess/Collision-Detection (CSMA/CD) protocol. The other version, TRANSPAR-VM, is designed in 1.2 m m CMOS and discretely integrated with VCSEL-MSM (Vertical-Cavity-Surface- Emitting-Laser and Metal-Semiconductor-Metal detectors) chips and driver/receiver chips on a printed circuit board. The TRANSPAR-VM provides an option of using the token ring network protocol in addition to the embedded functions of TRANSPAR-MQW. These optoelectronic smart pixel systems also require micro-optics devices to provide high resolution, high quality optical interconnections and external source arrays. In this research, we describe an innovative

  11. Pixel-based dust-extinction mapping in nearby galaxies: A new approach to lifting the veil of dust

    NASA Astrophysics Data System (ADS)

    Tamura, Kazuyuki

    In the first part of this dissertation, I explore a new approach to mapping dust extinction in galaxies, using the observed and estimated dust-free flux- ratios of optical V -band and mid-IR 3.6 micro-meter emission. Inferred missing V -band flux is then converted into an estimate of dust extinction. While dust features are not clearly evident in the observed ground-based images of NGC 0959, the target of my pilot study, the dust-map created with this method clearly traces the distribution of dust seen in higher resolution Hubble images. Stellar populations are then analyzed through various pixel Color- Magnitude Diagrams and pixel Color-Color Diagrams (pCCDs), both before and after extinction correction. The ( B - 3.6 microns) versus (far-UV - U ) pCCD proves particularly powerful to distinguish pixels that are dominated by different types of or mixtures of stellar populations. Mapping these pixel- groups onto a pixel-coordinate map shows that they are not distributed randomly, but follow genuine galactic structures, such as a previously unrecognized bar. I show that selecting pixel-groups is not meaningful when using uncorrected colors, and that pixel-based extinction correction is crucial to reveal the true spatial variations in stellar populations. This method is then applied to a sample of late-type galaxies to study the distribution of dust and stellar population as a function of their morphological type and absolute magnitude. In each galaxy, I find that dust extinction is not simply decreasing radially, but that is concentrated in localized clumps throughout a galaxy. I also find some cases where star-formation regions are not associated with dust. In the second part, I describe the application of astronomical image analysis tools for medical purposes. In particular, Source Extractor is used to detect nerve fibers in the basement membrane images of human skin-biopsies of obese subjects. While more development and testing is necessary for this kind of work

  12. Efficient defect pixel cluster detection and correction for Bayer CFA image sequences

    NASA Astrophysics Data System (ADS)

    Tajbakhsh, Touraj

    2011-01-01

    Image sensor arrays may have defect pixels, either originating from manufacturing or being developed over the lifetime of the image sensor array. Continuous defect pixel detection and correction performing during camera runtime is desirable. On-the-fly detection and correction is challenging since edges and high-frequency image content might get identified as defect pixel regions and intact pixels become corrupted during defect pixel replacement. We propose a table-based detection and correction method which by and by fills the non-volatile table during normal camera operation. In this work we model defect pixels and pixel clusters to be stuck to fixed values or at least fixed to a narrow value range whereas the local neighborhood of these pixels indicate a normal behavior. The idea is to temporally observe the value ranges of small group of pixels (e.g. 4x4 pixel blocks) and to decide about their defective condition depending on their variability with respect to their neighbor pixels. Our method is computationally efficient, requires no frame buffer, requires modest memory, and therefore is appropriate to operate in line-buffer based image signal processing (ISP) systems. Our results indicate high reliability in terms of detection rates and robustness against high-frequency image content. As part of the defect pixel replacement system we also propose a simple and efficient defect pixel correction method based on the mean of medians operating on the Bayer CFA image domain.

  13. Current progress on pixel level packaging for uncooled IRFPA

    NASA Astrophysics Data System (ADS)

    Dumont, G.; Rabaud, W.; Yon, J.-J.; Carle, L.; Goudon, V.; Vialle, C.; Becker, Sébastien; Hamelin, Antoine; Arnaud, A.

    2012-06-01

    Vacuum packaging is definitely a major cost driver for uncooled IRFPA and a technological breakthrough is still expected to comply with the very low cost infrared camera market. To address this key issue, CEA-LETI is developing a Pixel Level Packaging (PLP) technology which basically consists in capping each pixel under vacuum in the direct continuation of the wafer level bolometer process. Previous CEA-LETI works have yet shown the feasibility of PLP based microbolometers that exhibit the required thermal insulation and vacuum achievement. CEA-LETI is still pushing the technology which has been now applied for the first time on a CMOS readout circuit. The paper will report on the recent progress obtained on PLP technology with particular emphasis on the optical efficiency of the PLP arrangement compared to the traditional microbolometer packaging. Results including optical performances, aging studies and compatibility with CMOS readout circuit are extensively presented.

  14. Bonding techniques for hybrid active pixel sensors (HAPS)

    NASA Astrophysics Data System (ADS)

    Bigas, M.; Cabruja, E.; Lozano, M.

    2007-05-01

    A hybrid active pixel sensor (HAPS) consists of an array of sensing elements which is connected to an electronic read-out unit. The most used way to connect these two different devices is bump bonding. This interconnection technique is very suitable for these systems because it allows a very fine pitch and a high number of I/Os. However, there are other interconnection techniques available such as direct bonding. This paper, as a continuation of a review [M. Lozano, E. Cabruja, A. Collado, J. Santander, M. Ullan, Nucl. Instr. and Meth. A 473 (1-2) (2001) 95-101] published in 2001, presents an update of the different advanced bonding techniques available for manufacturing a hybrid active pixel detector.

  15. Digital Pixel Sensor Array with Logarithmic Delta-Sigma Architecture

    PubMed Central

    Mahmoodi, Alireza; Li, Jing; Joseph, Dileepan

    2013-01-01

    Like the human eye, logarithmic image sensors achieve wide dynamic range easily at video rates, but, unlike the human eye, they suffer from low peak signal-to-noise-and-distortion ratios (PSNDRs). To improve the PSNDR, we propose integrating a delta-sigma analog-to-digital converter (ADC) in each pixel. An image sensor employing this architecture is designed, built and tested in 0.18 micron complementary metal-oxide-semiconductor (CMOS) technology. It achieves a PSNDR better than state-of-the-art logarithmic sensors and comparable to the human eye. As the approach concerns an array of many ADCs, we use a small-area low-power delta-sigma design. For scalability, each pixel has its own decimator. The prototype is compared to a variety of other image sensors, linear and nonlinear, from industry and academia. PMID:23959239

  16. Sub-pixel resolution with the Multispectral Thermal Imager (MTI).

    SciTech Connect

    Decker, Max Louis; Smith, Jody Lynn; Nandy, Prabal

    2003-06-01

    The Multispectral Thermal Imager Satellite (MTI) has been used to test a sub-pixel sampling technique in an effort to obtain higher spatial frequency imagery than that of its original design. The MTI instrument is of particular interest because of its infrared detectors. In this spectral region, the detector size is traditionally the limiting factor in determining the satellite's ground sampling distance (GSD). Additionally, many over-sampling techniques require flexible command and control of the sensor and spacecraft. The MTI sensor is well suited for this task, as it is the only imaging system on the MTI satellite bus. In this super-sampling technique, MTI is maneuvered such that the data are collected at sub-pixel intervals on the ground. The data are then processed using a deconvolution algorithm using in-scene measured point spread functions (PSF) to produce an image with synthetically-boosted GSD.

  17. Compressive holography with a single-pixel detector.

    PubMed

    Clemente, Pere; Durán, Vicente; Tajahuerce, Enrique; Andrés, Pedro; Climent, Vicent; Lancis, Jesús

    2013-07-15

    This Letter develops a framework for digital holography at optical wavelengths by merging phase-shifting interferometry with single-pixel optical imaging based on compressive sensing. The field diffracted by an input object is sampled by Hadamard patterns with a liquid crystal spatial light modulator. The concept of a single-pixel camera is then adapted to perform interferometric imaging of the sampled diffraction pattern by using a Mach-Zehnder interferometer. Phase-shifting techniques together with the application of a backward light propagation algorithm allow the complex amplitude of the object under scrutiny to be resolved. A proof-of-concept experiment evaluating the phase distribution of an ophthalmic lens with compressive phase-shifting holography is provided.

  18. MEDEA: a real time imaging pipeline for pixel lensing

    NASA Astrophysics Data System (ADS)

    Iovane, Gerardo; Capozziello, Salvatore; Longo, Giuseppe

    2003-05-01

    Pixel lensing is a technique used to search for baryonic components of dark matter (MACHOs) and allows detection of microlensing events even when the target galaxies are not resolved into individual stars. Potentially, it has the advantage of providing higher statistics than other methods but, unfortunately, traditional approaches to pixel lensing are very demanding in terms of computing time. We present the new, user friendly, tool MEDEA (Microlensing Experiment Data-Analysis Software for Events with Amplification). The package can be used either in a fully automatic or semi-automatic mode and can perform an on-line identification of events by means of a two level trigger and a quasi-on-line data analysis. The package will find application in the exploration of large databases as well as in the exploitation of specifically tailored future surveys.

  19. Using Trained Pixel Classifiers to Select Images of Interest

    NASA Technical Reports Server (NTRS)

    Mazzoni, D.; Wagstaff, K.; Castano, R.

    2004-01-01

    We present a machine-learning-based approach to ranking images based on learned priorities. Unlike previous methods for image evaluation, which typically assess the value of each image based on the presence of predetermined specific features, this method involves using two levels of machine-learning classifiers: one level is used to classify each pixel as belonging to one of a group of rather generic classes, and another level is used to rank the images based on these pixel classifications, given some example rankings from a scientist as a guide. Initial results indicate that the technique works well, producing new rankings that match the scientist's rankings significantly better than would be expected by chance. The method is demonstrated for a set of images collected by a Mars field-test rover.

  20. CMS Pixel Detector design for HL-LHC

    NASA Astrophysics Data System (ADS)

    Migliore, E.

    2016-12-01

    The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about 7.5×1034cm-2s-1 in 2028, to possibly reach an integrated luminosity of 3000 fb-1 by the end of 2037. This High Luminosity scenario, HL-LHC, will present new challenges in higher data rates and increased radiation. In order to maintain its physics reach the CMS collaboration has undertaken a preparation program of the detector known as Phase-2 upgrade. The CMS Phase-2 Pixel upgrade will require a high bandwidth readout system and high radiation tolerance for sensors and on-detector ASICs. Several technologies for the upgrade sensors are being studied. Serial powering schemes are under consideration to accommodate significant constraints on the system. These prospective designs, as well as new layout geometries that include very forward pixel discs, will be presented together with performance estimation.

  1. Skin segmentation using color pixel classification: analysis and comparison.

    PubMed

    Phung, Son Lam; Bouzerdoum, Abdesselam; Chai, Douglas

    2005-01-01

    This paper presents a study of three important issues of the color pixel classification approach to skin segmentation: color representation, color quantization, and classification algorithm. Our analysis of several representative color spaces using the Bayesian classifier with the histogram technique shows that skin segmentation based on color pixel classification is largely unaffected by the choice of the color space. However, segmentation performance degrades when only chrominance channels are used in classification. Furthermore, we find that color quantization can be as low as 64 bins per channel, although higher histogram sizes give better segmentation performance. The Bayesian classifier with the histogram technique and the multilayer perceptron classifier are found to perform better compared to other tested classifiers, including three piecewise linear classifiers, three unimodal Gaussian classifiers, and a Gaussian mixture classifier.

  2. Image pixel device using integrated organic electronic components

    NASA Astrophysics Data System (ADS)

    Swathi, K.; Narayan, K. S.

    2016-11-01

    We report a solution processed, monolithically integrated device similar to an imaging pixel element used in complementary metal-oxide semiconductor (CMOS) based cameras. This integrated pixel essentially consists of a pair of organic photodiode (OPD) and organic field effect transistor (OFET). The signal generated by the light responsive OPD drives the OFET to different output states to quantify the light intensity. The prerequisite of a low operating voltage OFET (<2 V) was achieved using a bottom-gate, top-contact OFET consisting of a high mobility polymer semiconductor and a self-assembled hybrid dielectric layer. A bulk heterojunction blend was used as the photo-active layer in the OPD along with suitable buffer layers for charge extraction. The material parameters were optimized to realize a suitable structure which clearly demonstrated the interplay of the OPD and OFET operations, thereby forming a roadmap for all-organic CMOS arrays.

  3. The Hybrid Pixel Single Photon Counting Detector XPAD

    SciTech Connect

    Hustache-Ottini, S.; Bordessoule, M.; Medjoubi, K.; Berar, J.-F.; Boudet, N.; Caillot, B.

    2007-01-19

    The XPAD detector is a 2D X-ray imager based on hybrid pixel technology, gathering 38400 pixels on a surface of 68*68 mm2. It is a photon counting detector, with low noise, wide dynamic range and high speed read out, which make it particularly suitable for third generation synchrotron applications, such as diffraction, small angle X-ray scattering or macro-molecular crystallography, but also for small animal imaging. High resolution powder diffraction data and in situ scattering data of crystallization of liquid oxides are presented to illustrate the properties of this detector, resulting in a significant gain in data acquisition time and a capability to follow fast kinetics in real time experiments. The characteristics of the future generation of XPAD detector, which will be available in 2007, are also presented.

  4. New SOFRADIR 10μm pixel pitch infrared products

    NASA Astrophysics Data System (ADS)

    Lefoul, X.; Pere-Laperne, N.; Augey, T.; Rubaldo, L.; Aufranc, Sébastien; Decaens, G.; Ricard, N.; Mazaleyrat, E.; Billon-Lanfrey, D.; Gravrand, Olivier; Bisotto, Sylvette

    2014-10-01

    Recent advances in miniaturization of IR imaging technology have led to a growing market for mini thermal-imaging sensors. In that respect, Sofradir development on smaller pixel pitch has made much more compact products available to the users. When this competitive advantage is mixed with smaller coolers, made possible by HOT technology, we achieved valuable reductions in the size, weight and power of the overall package. At the same time, we are moving towards a global offer based on digital interfaces that provides our customers simplifications at the IR system design process while freeing up more space. This paper discusses recent developments on hot and small pixel pitch technologies as well as efforts made on compact packaging solution developed by SOFRADIR in collaboration with CEA-LETI.

  5. Pixel detector system development at Diamond Light Source

    NASA Astrophysics Data System (ADS)

    Marchal, J.; Horswell, I.; Gimenez, E. N.; Tartoni, N.

    2010-10-01

    Hybrid pixel detectors consisting of an array of silicon photodiodes bump-bonded to CMOS read-out chips provide high signal-to-noise ratio and high dynamic range compared to CCD-based detectors and Image Plates. These detector features are important for SAXS experiments where a wide range of intensities are present in the images. For time resolved SAXS experiments, high frame rates are compulsory. The latest CMOS read-out chip developed by the MEDIPIX collaboration provides high frame rate and continuous acquisition mode. A read-out system for an array of MEDIPIX3 sensors is under development at Diamond Light Source. This system will support a full resolution frame rate of 1 kHz at a pixel counter depth of 12-bit and a frame rate of 30 kHz at a counter depth of 1 bit. Details concerning system design and MEDIPIX sensors characterization are presented.

  6. Measurement results of DIPIX pixel sensor developed in SOI technology

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohammed Imran; Arai, Yasuo; Idzik, Marek; Kapusta, Piotr; Miyoshi, Toshinobu; Turala, Michal

    2013-08-01

    The development of integration type pixel detectors presents interest for physics communities because it brings optimization of design, simplicity of production-which means smaller cost, and reduction of detector material budget. During the last decade a lot of research and development activities took place in the field of CMOS Silicon-On-Insulator (SOI) technology resulting in improvement in wafer size, wafer resistivity and MIM capacitance. Several ideas have been tested successfully and are gradually entering into the application phase. Some of the novel concepts exploring SOI technology are pursued at KEK; several prototypes of dual mode integration type pixel (DIPIX) have been recently produced and described. This report presents initial test results of some of the prototypes including tests obtained with the infrared laser beams and Americium (Am-241) source. The Equivalent Noise Charge (ENC) of 86 e - has been measured. The measured performance demonstrates that SOI technology is a feasible choice for future applications.

  7. Pixel extraction based integral imaging with controllable viewing direction

    NASA Astrophysics Data System (ADS)

    Ji, Chao-Chao; Deng, Huan; Wang, Qiong-Hua

    2012-09-01

    We propose pixel extraction based integral imaging with a controllable viewing direction. The proposed integral imaging can provide viewers three-dimensional (3D) images in a very small viewing angle. The viewing angle and the viewing direction of the reconstructed 3D images are controlled by the pixels extracted from an elemental image array. Theoretical analysis and a 3D display experiment of the viewing direction controllable integral imaging are carried out. The experimental results verify the correctness of the theory. A 3D display based on the integral imaging can protect the viewer’s privacy and has huge potential for a television to show multiple 3D programs at the same time.

  8. Distance measurement based on pixel variation of CCD images.

    PubMed

    Hsu, Chen-Chien; Lu, Ming-Chih; Wang, Wei-Yen; Lu, Yin-Yu

    2009-10-01

    This paper presents a distance measurement method based on pixel number variation of CCD images by referencing to two arbitrarily designated points in the image frames. By establishing a relationship between the displacement of the camera movement along the photographing direction and the difference in pixel count between reference points in the images, the distance from an object can be calculated via the proposed method. To integrate the measuring functions into digital cameras, a circuit design implementing the proposed measuring system in selecting reference points, measuring distance, and displaying measurement results on CCD panel of the digital camera is proposed in this paper. In comparison to pattern recognition or image analysis methods, the proposed measuring approach is simple and straightforward for practical implementation into digital cameras. To validate the performance of the proposed method, measurement results using the proposed method and ultrasonic rangefinders are also presented in this paper.

  9. Sensor Development and Readout Prototyping for the STAR Pixel Detector

    SciTech Connect

    Greiner, L.; Anderssen, E.; Matis, H.S.; Ritter, H.G.; Stezelberger, T.; Szelezniak, M.; Sun, X.; Vu, C.; Wieman, H.

    2009-01-14

    The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) is designing a new vertex detector. The purpose of this upgrade detector is to provide high resolution pointing to allow for the direct topological reconstruction of heavy flavor decays such as the D{sup 0} by finding vertices displaced from the collision vertex by greater than 60 microns. We are using Monolithic Active Pixel Sensor (MAPS) as the sensor technology and have a coupled sensor development and readout system plan that leads to a final detector with a <200 {micro}s integration time, 400 M pixels and a coverage of -1 < {eta} < 1. We present our coupled sensor and readout development plan and the status of the prototyping work that has been accomplished.

  10. Secured Medical Images - a Chaotic Pixel Scrambling Approach.

    PubMed

    Parvees, M Y Mohamed; Samath, J Abdul; Bose, B Parameswaran

    2016-11-01

    In this paper, a cryptosystem is proposed to encrypt 16-bit monochrome DICOM image using enhanced chaotic economic map. A new enhanced chaotic economic map (ECEM) is designed from the chaotic economic map which has better bifurcation nature and positive Lyapunov exponent values. In order to improve the sternness of the encryption algorithm, the enhanced chaotic map is employed to generate the pixel permutation, masking, and swapping sequences. The substitution operation is introduced in-between the standard permutation and diffusion operations. The robustness of the proposed image encryption algorithm is measured by various analyses such as histogram, key sensitivity, key space, number of pixel change rate (NPCR), unified average change intensity (UACI), information entropy and correlation coefficient. The results of the security analyses are compared with existing algorithms to validate that the proposed algorithm is better in terms of larger key space to resist brute force attacks and other common attacks on encryption.

  11. Digital pixel sensor array with logarithmic delta-sigma architecture.

    PubMed

    Mahmoodi, Alireza; Li, Jing; Joseph, Dileepan

    2013-08-16

    Like the human eye, logarithmic image sensors achieve wide dynamic range easily at video rates, but, unlike the human eye, they suffer from low peak signal-to-noise-and-distortion ratios (PSNDRs). To improve the PSNDR, we propose integrating a delta-sigma analog-to-digital converter (ADC) in each pixel. An image sensor employing this architecture is designed, built and tested in 0.18 micron complementary metal-oxide-semiconductor (CMOS) technology. It achieves a PSNDR better than state-of-the-art logarithmic sensors and comparable to the human eye. As the approach concerns an array of many ADCs, we use a small-area low-power delta-sigma design. For scalability, each pixel has its own decimator. The prototype is compared to a variety of other image sensors, linear and nonlinear, from industry and academia.

  12. Performance assessment of a single-pixel compressive sensing imaging system

    NASA Astrophysics Data System (ADS)

    Du Bosq, Todd W.; Preece, Bradley L.

    2016-05-01

    Conventional electro-optical and infrared (EO/IR) systems capture an image by measuring the light incident at each of the millions of pixels in a focal plane array. Compressive sensing (CS) involves capturing a smaller number of unconventional measurements from the scene, and then using a companion process known as sparse reconstruction to recover the image as if a fully populated array that satisfies the Nyquist criteria was used. Therefore, CS operates under the assumption that signal acquisition and data compression can be accomplished simultaneously. CS has the potential to acquire an image with equivalent information content to a large format array while using smaller, cheaper, and lower bandwidth components. However, the benefits of CS do not come without compromise. The CS architecture chosen must effectively balance between physical considerations (SWaP-C), reconstruction accuracy, and reconstruction speed to meet operational requirements. To properly assess the value of such systems, it is necessary to fully characterize the image quality, including artifacts and sensitivity to noise. Imagery of the two-handheld object target set at range was collected using a passive SWIR single-pixel CS camera for various ranges, mirror resolution, and number of processed measurements. Human perception experiments were performed to determine the identification performance within the trade space. The performance of the nonlinear CS camera was modeled with the Night Vision Integrated Performance Model (NV-IPM) by mapping the nonlinear degradations to an equivalent linear shift invariant model. Finally, the limitations of CS modeling techniques will be discussed.

  13. Performance assessment of a compressive sensing single-pixel imaging system

    NASA Astrophysics Data System (ADS)

    Du Bosq, Todd W.; Preece, Bradley L.

    2017-04-01

    Conventional sensors measure the light incident at each pixel in a focal plane array. Compressive sensing (CS) involves capturing a smaller number of unconventional measurements from the scene, and then using a companion process to recover the image. CS has the potential to acquire imagery with equivalent information content to a large format array while using smaller, cheaper, and lower bandwidth components. However, the benefits of CS do not come without compromise. The CS architecture chosen must effectively balance between physical considerations, reconstruction accuracy, and reconstruction speed to meet operational requirements. Performance modeling of CS imagers is challenging due to the complexity and nonlinearity of the system and reconstruction algorithm. To properly assess the value of such systems, it is necessary to fully characterize the image quality, including artifacts and sensitivity to noise. Imagery of a two-handheld object target set was collected using an shortwave infrared single-pixel CS camera for various ranges and number of processed measurements. Human perception experiments were performed to determine the identification performance within the trade space. The performance of the nonlinear CS camera was modeled by mapping the nonlinear degradations to an equivalent linear shift invariant model. Finally, the limitations of CS modeling techniques are discussed.

  14. A new data acquisition system for the CMS Phase 1 pixel detector

    NASA Astrophysics Data System (ADS)

    Kornmayer, A.

    2016-12-01

    A new pixel detector will be installed in the CMS experiment during the extended technical stop of the LHC at the beginning of 2017. The new pixel detector, built from four layers in the barrel region and three layers on each end of the forward region, is equipped with upgraded front-end readout electronics, specifically designed to handle the high particle hit rates created in the LHC environment. The DAQ back-end was entirely redesigned to handle the increased number of readout channels, the higher data rates per channel and the new digital data format. Based entirely on the microTCA standard, new front-end controller (FEC) and front-end driver (FED) cards have been developed, prototyped and produced with custom optical link mezzanines mounted on the FC7 AMC and custom firmware. At the same time as the new detector is being assembled, the DAQ system is set up and its integration into the CMS central DAQ system tested by running the pilot blade detector already installed in CMS. This work describes the DAQ system, integration tests and gives an outline for the activities up to commissioning the final system at CMS in 2017.

  15. Broadband Terahertz Computed Tomography Using a 5k-pixel Real-time THz Camera

    NASA Astrophysics Data System (ADS)

    Trichopoulos, Georgios C.; Sertel, Kubilay

    2015-07-01

    We present a novel THz computed tomography system that enables fast 3-dimensional imaging and spectroscopy in the 0.6-1.2 THz band. The system is based on a new real-time broadband THz camera that enables rapid acquisition of multiple cross-sectional images required in computed tomography. Tomographic reconstruction is achieved using digital images from the densely-packed large-format (80×64) focal plane array sensor located behind a hyper-hemispherical silicon lens. Each pixel of the sensor array consists of an 85 μm × 92 μm lithographically fabricated wideband dual-slot antenna, monolithically integrated with an ultra-fast diode tuned to operate in the 0.6-1.2 THz regime. Concurrently, optimum impedance matching was implemented for maximum pixel sensitivity, enabling 5 frames-per-second image acquisition speed. As such, the THz computed tomography system generates diffraction-limited resolution cross-section images as well as the three-dimensional models of various opaque and partially transparent objects. As an example, an over-the-counter vitamin supplement pill is imaged and its material composition is reconstructed. The new THz camera enables, for the first time, a practical application of THz computed tomography for non-destructive evaluation and biomedical imaging.

  16. Ionogram trace enhancement based on image pixel connectedness

    NASA Astrophysics Data System (ADS)

    Lu, Hongguang; Ji, Guangrong; Zheng, Haiyong; Zhao, Zhenwei; He, Shaohong

    2013-07-01

    This paper proposes a novel idea for ionogram trace enhancement to obtain the "clean" ionogram with real ionospheric echo signals, which is very important for further ionogram interpretation and scaling manually or automatically. Two methods based on ionogram trace pixel connectedness are adopted: max filter and connected components labeling. The experiments show that both methods are feasible and effective, and parameter selection and time complexity of the two methods are analyzed.

  17. Automated detection of BB pixel clusters in digital fluoroscopic images

    NASA Astrophysics Data System (ADS)

    Cho, Paul S.; Johnson, Roger H.

    1998-09-01

    Small ball bearings (BBs) are often used to characterize and correct for geometric distortion of x-ray image intensifiers. For quantitative applications the number of BBs required for accurate distortion correction is prohibitively large for manual detection. A method to automatically determine the BB coordinates is described. The technique consists of image segmentation, pixel coalescing and centroid calculation. The dependence of calculated BB coordinates on segmentation threshold was also evaluated and found to be within the uncertainty of measurement.

  18. Performance studies of Micro Pixel Chamber for the ATLAS upgrade

    NASA Astrophysics Data System (ADS)

    Komai, H.; Ochi, A.; Homma, Y.; Edo, Y.; Yamaguchi, T.

    2013-03-01

    The Micro Pixel Chamber (μ-PIC) is being developed as a muon chamber of the ATLAS experiment in an HL-LHC environment. In the ATLAS muon system, a high flux of fast neutron background causes instability operation of the detectors. We performed neutron irradiation tests with μ-PIC to optimize the operation gas and detector structure. In addition, we studied neutron interactions with the detector, in order to understand the effect of fast neutrons.

  19. Planar slim-edge pixel sensors for the ATLAS upgrades

    NASA Astrophysics Data System (ADS)

    Altenheiner, S.; Goessling, C.; Jentzsch, J.; Klingenberg, R.; Lapsien, T.; Muenstermann, D.; Rummler, A.; Troska, G.; Wittig, T.

    2012-02-01

    The ATLAS detector at CERN is a general-purpose experiment at the Large Hadron Collider (LHC). The ATLAS Pixel Detector is the innermost tracking detector of ATLAS and requires a sufficient level of hermeticity to achieve superb track reconstruction performance. The current planar n-type pixel sensors feature a pixel matrix of n+-implantations which is (on the opposite p-side) surrounded by so-called guard rings to reduce the high voltage stepwise towards the cutting edge and an additional safety margin. Because of the inactive region around the active area, the sensor modules have been shingled on top of each other's edge which limits the thermal performance and adds complexity in the present detector. The first upgrade phase of the ATLAS pixel detector will consist of the insertable b-layer (IBL), an additional b-layer which will be inserted into the present detector in 2013. Several changes in the sensor design with respect to the existing detector had to be applied to comply with the IBL's specifications and are described in detail. A key issue for the ATLAS upgrades is a flat arrangement of the sensors. To maintain the required level of hermeticity in the detector, the inactive sensor edges have to be reduced to minimize the dead space between the adjacent detector modules. Unirradiated and irradiated sensors with the IBL design have been operated in test beams to study the efficiency performance in the sensor edge region and it was found that the inactive edge width could be reduced from 1100 μm to less than 250 μm.

  20. A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager

    PubMed Central

    Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

    2012-01-01

    Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm2 at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm2. Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm2 while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt. PMID:23136624