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Sample records for streak camera observations

  1. X-ray streak camera for observation of tightly pinched relativistic electron beams

    International Nuclear Information System (INIS)

    Johnson, D.J.

    1977-01-01

    A pinhole camera is coupled with a Pilot-B scintillator and image-intensified TRW streak camera to study pinched electron beam profiles via observation of anode target bremsstrahlung. Streak intensification is achieved with an EMI image intensifier operated at a gain of up to 10 6 which allows optimizing the pinhole configuration so that resolution is simultaneously limited by photon-counting statistics and pinhole geometry. The pinhole used is one-dimensional and is fabricated by inserting uranium shims with hyperbolic curved edges between two 5-cm-thick lead blocks. The loss of spatial resolution due to the x-ray transmission through the perimeter of the pinhole is calculated and a streak photograph of a Gamble I pinched beam interacting with a brass anode is presented

  2. Ultra fast x-ray streak camera

    International Nuclear Information System (INIS)

    Coleman, L.W.; McConaghy, C.F.

    1975-01-01

    A unique ultrafast x-ray sensitive streak camera, with a time resolution of 50psec, has been built and operated. A 100A thick gold photocathode on a beryllium vacuum window is used in a modified commerical image converter tube. The X-ray streak camera has been used in experiments to observe time resolved emission from laser-produced plasmas. (author)

  3. Streak cameras and their applications

    International Nuclear Information System (INIS)

    Bernet, J.M.; Imhoff, C.

    1987-01-01

    Over the last several years, development of various measurement techniques in the nanosecond and pico-second range has led to increased reliance on streak cameras. This paper will present the main electronic and optoelectronic performances of the Thomson-CSF TSN 506 cameras and their associated devices used to build an automatic image acquisition and processing system (NORMA). A brief survey of the diversity and the spread of the use of high speed electronic cinematography will be illustrated by a few typical applications [fr

  4. Streak camera recording of interferometer fringes

    International Nuclear Information System (INIS)

    Parker, N.L.; Chau, H.H.

    1977-01-01

    The use of an electronic high-speed camera in the streaking mode to record interference fringe motion from a velocity interferometer is discussed. Advantages of this method over the photomultiplier tube-oscilloscope approach are delineated. Performance testing and data for the electronic streak camera are discussed. The velocity profile of a mylar flyer accelerated by an electrically exploded bridge, and the jump-off velocity of metal targets struck by these mylar flyers are measured in the camera tests. Advantages of the streak camera include portability, low cost, ease of operation and maintenance, simplified interferometer optics, and rapid data analysis

  5. Notes on the IMACON 500 streak camera system

    International Nuclear Information System (INIS)

    Clendenin, J.E.

    1985-01-01

    The notes provided are intended to supplement the instruction manual for the IMACON 500 streak camera system. The notes cover the streak analyzer, instructions for timing the streak camera, and calibration

  6. Compact Optical Technique for Streak Camera Calibration

    International Nuclear Information System (INIS)

    Curt Allen; Terence Davies; Frans Janson; Ronald Justin; Bruce Marshall; Oliver Sweningsen; Perry Bell; Roger Griffith; Karla Hagans; Richard Lerche

    2004-01-01

    The National Ignition Facility is under construction at the Lawrence Livermore National Laboratory for the U.S. Department of Energy Stockpile Stewardship Program. Optical streak cameras are an integral part of the experimental diagnostics instrumentation. To accurately reduce data from the streak cameras a temporal calibration is required. This article describes a technique for generating trains of precisely timed short-duration optical pulses that are suitable for temporal calibrations

  7. Soft x-ray streak cameras

    International Nuclear Information System (INIS)

    Stradling, G.L.

    1988-01-01

    This paper is a discussion of the development and of the current state of the art in picosecond soft x-ray streak camera technology. Accomplishments from a number of institutions are discussed. X-ray streak cameras vary from standard visible streak camera designs in the use of an x-ray transmitting window and an x-ray sensitive photocathode. The spectral sensitivity range of these instruments includes portions of the near UV and extends from the subkilovolt x- ray region to several tens of kilovolts. Attendant challenges encountered in the design and use of x-ray streak cameras include the accommodation of high-voltage and vacuum requirements, as well as manipulation of a photocathode structure which is often fragile. The x-ray transmitting window is generally too fragile to withstand atmospheric pressure, necessitating active vacuum pumping and a vacuum line of sight to the x-ray signal source. Because of the difficulty of manipulating x-ray beams with conventional optics, as is done with visible light, the size of the photocathode sensing area, access to the front of the tube, the ability to insert the streak tube into a vacuum chamber and the capability to trigger the sweep with very short internal delay times are issues uniquely relevant to x-ray streak camera use. The physics of electron imaging may place more stringent limitations on the temporal and spatial resolution obtainable with x-ray photocathodes than with the visible counterpart. Other issues which are common to the entire streak camera community also concern the x-ray streak camera users and manufacturers

  8. Compact Optical Technique for Streak Camera Calibration

    International Nuclear Information System (INIS)

    Bell, P; Griffith, R; Hagans, K; Lerche, R; Allen, C; Davies, T; Janson, F; Justin, R; Marshall, B; Sweningsen, O

    2004-01-01

    The National Ignition Facility (NIF) is under construction at the Lawrence Livermore National Laboratory (LLNL) for the U.S. Department of Energy Stockpile Stewardship Program. Optical streak cameras are an integral part of the experimental diagnostics instrumentation. To accurately reduce data from the streak cameras a temporal calibration is required. This article describes a technique for generating trains of precisely timed short-duration optical pulses1 (optical comb generators) that are suitable for temporal calibrations. These optical comb generators (Figure 1) are used with the LLNL optical streak cameras. They are small, portable light sources that produce a series of temporally short, uniformly spaced, optical pulses. Comb generators have been produced with 0.1, 0.5, 1, 3, 6, and 10-GHz pulse trains of 780-nm wavelength light with individual pulse durations of ∼25-ps FWHM. Signal output is via a fiber-optic connector. Signal is transported from comb generator to streak camera through multi-mode, graded-index optical fibers. At the NIF, ultra-fast streak-cameras are used by the Laser Fusion Program experimentalists to record fast transient optical signals. Their temporal resolution is unmatched by any other transient recorder. Their ability to spatially discriminate an image along the input slit allows them to function as a one-dimensional image recorder, time-resolved spectrometer, or multichannel transient recorder. Depending on the choice of photocathode, they can be made sensitive to photon energies from 1.1 eV to 30 keV and beyond. Comb generators perform two important functions for LLNL streak-camera users. First, comb generators are used as a precision time-mark generator for calibrating streak camera sweep rates. Accuracy is achieved by averaging many streak camera images of comb generator signals. Time-base calibrations with portable comb generators are easily done in both the calibration laboratory and in situ. Second, comb signals are applied

  9. The LLL compact 10-ps streak camera

    International Nuclear Information System (INIS)

    Thomas, S.W.; Houghton, J.W.; Tripp, G.R.; Coleman, L.W.

    1975-01-01

    The 10-ps streak camera has been redesigned to simplify its operation, reduce manufacturing costs, and improve its appearance. The electronics have been simplified, a film indexer added, and a contacted slit has been evaluated. Data support a 10-ps resolution. (author)

  10. Traveling wave deflector design for femtosecond streak camera

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  11. Traveling wave deflector design for femtosecond streak camera

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-21

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

  12. Compact optical technique for streak camera calibration

    International Nuclear Information System (INIS)

    Bell, Perry; Griffith, Roger; Hagans, Karla; Lerche, Richard; Allen, Curt; Davies, Terence; Janson, Frans; Justin, Ronald; Marshall, Bruce; Sweningsen, Oliver

    2004-01-01

    To produce accurate data from optical streak cameras requires accurate temporal calibration sources. We have reproduced an older technology for generating optical timing marks that had been lost due to component availability. Many improvements have been made which allow the modern units to service a much larger need. Optical calibrators are now available that produce optical pulse trains of 780 nm wavelength light at frequencies ranging from 0.1 to 10 GHz, with individual pulse widths of approximately 25 ps full width half maximum. Future plans include the development of single units that produce multiple frequencies to cover a wide temporal range, and that are fully controllable via an RS232 interface

  13. Compact optical technique for streak camera calibration

    Science.gov (United States)

    Bell, Perry; Griffith, Roger; Hagans, Karla; Lerche, Richard; Allen, Curt; Davies, Terence; Janson, Frans; Justin, Ronald; Marshall, Bruce; Sweningsen, Oliver

    2004-10-01

    To produce accurate data from optical streak cameras requires accurate temporal calibration sources. We have reproduced an older technology for generating optical timing marks that had been lost due to component availability. Many improvements have been made which allow the modern units to service a much larger need. Optical calibrators are now available that produce optical pulse trains of 780 nm wavelength light at frequencies ranging from 0.1 to 10 GHz, with individual pulse widths of approximately 25 ps full width half maximum. Future plans include the development of single units that produce multiple frequencies to cover a wide temporal range, and that are fully controllable via an RS232 interface.

  14. Picosecond x-ray streak cameras

    Science.gov (United States)

    Averin, V. I.; Bryukhnevich, Gennadii I.; Kolesov, G. V.; Lebedev, Vitaly B.; Miller, V. A.; Saulevich, S. V.; Shulika, A. N.

    1991-04-01

    The first multistage image converter with an X-ray photocathode (UMI-93 SR) was designed in VNIIOFI in 1974 [1]. The experiments carried out in IOFAN pointed out that X-ray electron-optical cameras using the tube provided temporal resolution up to 12 picoseconds [2]. The later work has developed into the creation of the separate streak and intensifying tubes. Thus, PV-003R tube has been built on base of UMI-93SR design, fibre optically connected to PMU-2V image intensifier carrying microchannel plate.

  15. Characteristics of uranium oxide cathode for neutron streak camera

    International Nuclear Information System (INIS)

    Niki, H.; Itoga, K.; Yamanaka, M.; Yamanaka, T.; Yamanaka, C.

    1986-01-01

    In laser fusion research, time-resolved neutron measurements require 20ps resolution in order to obtain the time history of the D-T burn. Uranium oxide was expected to be a sensitive material as a cathode of a neutron streak camera because of its large fission cross section. The authors report their measurements of some characteristics of the uranium oxide cathode connected to a conventional streak tube. 14 MeV neutron signal were observed as the bright spots on a TV monitor using a focus mode opration. Detection efficiency was ∼ 1 x 10 -6 for 1 μm thick cathode. Each signal consisted of more than several tens of components, which were corresponding to the secondary electrons dragged out from the cathode by a fission fragment. Time resolution is thought to be limited mainly by the transit time spread of the secondary electrons. 14ps resolution was obtained by a streak mode operation for a single fission event

  16. Sweep time performance of optic streak camera

    International Nuclear Information System (INIS)

    Wang Zhebin; Yang Dong; Zhang Huige

    2012-01-01

    The sweep time performance of the optic streak camera (OSC) is of critical importance to its application. The systematic analysis of full-screen sweep velocity shows that the traditional method based on the averaged velocity and its nonlinearity would increase the uncertainty of sweep time and can not reflect the influence of the spatial distortion of OSC. A elaborate method for sweep time has been developed with the aid of full-screen sweep velocity and its uncertainty. It is proved by the theoretical analysis and experimental study that the method would decrease the uncertainty of sweep time within 1%, which would improve the accuracy of sweep time and the reliability of OSC application. (authors)

  17. Flat-field response and geometric distortion measurements of optical streak cameras

    International Nuclear Information System (INIS)

    Montgomery, D.S.; Drake, R.P.; Jones, B.A.; Wiedwald, J.D.

    1987-08-01

    To accurately measure pulse amplitude, shape, and relative time histories of optical signals with an optical streak camera, it is necessary to correct each recorded image for spatially-dependent gain nonuniformity and geometric distortion. Gain nonuniformities arise from sensitivity variations in the streak-tube photocathode, phosphor screen, image-intensifier tube, and image recording system. These nonuniformities may be severe, and have been observed to be on the order of 100% for some LLNL optical streak cameras. Geometric distortion due to optical couplings, electron-optics, and sweep nonlinearity not only affects pulse position and timing measurements, but affects pulse amplitude and shape measurements as well. By using a 1.053-μm, long-pulse, high-power laser to generate a spatially and temporally uniform source as input to the streak camera, the combined effects of flat-field response and geometric distortion can be measured under the normal dynamic operation of cameras with S-1 photocathodes. Additionally, by using the same laser system to generate a train of short pulses that can be spatially modulated at the input of the streak camera, we can effectively create a two-dimensional grid of equally-spaced pulses. This allows a dynamic measurement of the geometric distortion of the streak camera. We will discuss the techniques involved in performing these calibrations, will present some of the measured results for LLNL optical streak cameras, and will discuss software methods to correct for these effects. 6 refs., 6 figs

  18. Triggered streak and framing rotating-mirror cameras

    International Nuclear Information System (INIS)

    Huston, A.E.; Tabrar, A.

    1975-01-01

    A pulse motor has been developed which enables a mirror to be rotated to speeds in excess of 20,000 rpm with 10 -4 s. High-speed cameras of both streak and framing type have been assembled which incorporate this mirror drive, giving streak writing speeds up to 2,000ms -1 , and framing speeds up to 500,000 frames s -1 , in each case with the capability of triggering the camera from the event under investigation. (author)

  19. Dynamic range studies of the RCA streak tube in the LLL streak camera

    International Nuclear Information System (INIS)

    Thomas, S.W.; Phillips, G.E.

    1979-01-01

    As indicated by tests on several cameras, the dynamic range of the Lawrence Livermore Laboratory streak-camera system appears to be about two orders of magnitude greater than those reported for other systems for 10- to 200-ps pulses. The lack of a fine mesh grid in the RCA streak tube used in these cameras probably contributes to a lower system dynamic noise and therefore raises the dynamic range. A developmental tube with a mesh grid was tested and supports this conjecture. Order-of-magnitude variations in input slit width do not affect the spot size on the phosphor or the dynamic range of the RCA tube. (author)

  20. A time-resolved image sensor for tubeless streak cameras

    Science.gov (United States)

    Yasutomi, Keita; Han, SangMan; Seo, Min-Woong; Takasawa, Taishi; Kagawa, Keiichiro; Kawahito, Shoji

    2014-03-01

    This paper presents a time-resolved CMOS image sensor with draining-only modulation (DOM) pixels for tube-less streak cameras. Although the conventional streak camera has high time resolution, the device requires high voltage and bulky system due to the structure with a vacuum tube. The proposed time-resolved imager with a simple optics realize a streak camera without any vacuum tubes. The proposed image sensor has DOM pixels, a delay-based pulse generator, and a readout circuitry. The delay-based pulse generator in combination with an in-pixel logic allows us to create and to provide a short gating clock to the pixel array. A prototype time-resolved CMOS image sensor with the proposed pixel is designed and implemented using 0.11um CMOS image sensor technology. The image array has 30(Vertical) x 128(Memory length) pixels with the pixel pitch of 22.4um. .

  1. Streak camera imaging of single photons at telecom wavelength

    Science.gov (United States)

    Allgaier, Markus; Ansari, Vahid; Eigner, Christof; Quiring, Viktor; Ricken, Raimund; Donohue, John Matthew; Czerniuk, Thomas; Aßmann, Marc; Bayer, Manfred; Brecht, Benjamin; Silberhorn, Christine

    2018-01-01

    Streak cameras are powerful tools for temporal characterization of ultrafast light pulses, even at the single-photon level. However, the low signal-to-noise ratio in the infrared range prevents measurements on weak light sources in the telecom regime. We present an approach to circumvent this problem, utilizing an up-conversion process in periodically poled waveguides in Lithium Niobate. We convert single photons from a parametric down-conversion source in order to reach the point of maximum detection efficiency of commercially available streak cameras. We explore phase-matching configurations to apply the up-conversion scheme in real-world applications.

  2. Soft x-ray streak camera for laser fusion applications

    International Nuclear Information System (INIS)

    Stradling, G.L.

    1981-04-01

    This thesis reviews the development and significance of the soft x-ray streak camera (SXRSC) in the context of inertial confinement fusion energy development. A brief introduction of laser fusion and laser fusion diagnostics is presented. The need for a soft x-ray streak camera as a laser fusion diagnostic is shown. Basic x-ray streak camera characteristics, design, and operation are reviewed. The SXRSC design criteria, the requirement for a subkilovolt x-ray transmitting window, and the resulting camera design are explained. Theory and design of reflector-filter pair combinations for three subkilovolt channels centered at 220 eV, 460 eV, and 620 eV are also presented. Calibration experiments are explained and data showing a dynamic range of 1000 and a sweep speed of 134 psec/mm are presented. Sensitivity modifications to the soft x-ray streak camera for a high-power target shot are described. A preliminary investigation, using a stepped cathode, of the thickness dependence of the gold photocathode response is discussed. Data from a typical Argus laser gold-disk target experiment are shown

  3. Reliable and repeatable characterization of optical streak cameras

    International Nuclear Information System (INIS)

    Charest, Michael R. Jr.; Torres, Peter III; Silbernagel, Christopher T.; Kalantar, Daniel H.

    2008-01-01

    Optical streak cameras are used as primary diagnostics for a wide range of physics and laser experiments at facilities such as the National Ignition Facility. To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electrical components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases, the characterization data are applied to the raw data images to correct for the nonlinearities. In order to characterize an optical streak camera, a specific set of data is collected, where the response to defined inputs are recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, and temporal resolution from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information.

  4. Reliable and Repeatable Characterization of Optical Streak Cameras

    International Nuclear Information System (INIS)

    Kalantar, D; Charest, M; Torres III, P; Charest, M

    2008-01-01

    Optical streak cameras are used as primary diagnostics for a wide range of physics and laser experiments at facilities such as the National Ignition Facility (NIF). To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electrical components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases, the characterization data are applied to the raw data images to correct for the nonlinearities. In order to characterize an optical streak camera, a specific set of data is collected, where the response to defined inputs are recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, and temporal resolution from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information

  5. Reliable and Repeatable Characterization of Optical Streak Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Michael Charest Jr., Peter Torres III, Christopher Silbernagel, and Daniel Kalantar

    2008-10-31

    Optical streak cameras are used as primary diagnostics for a wide range of physics and laser experiments at facilities such as the National Ignition Facility (NIF). To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electrical components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases, the characterization data are applied to the raw data images to correct for the nonlinearities. In order to characterize an optical streak camera, a specific set of data is collected, where the response to defined inputs are recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, and temporal resolution from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information.

  6. Reliable and Repeatable Characterication of Optical Streak Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Kalantar, D; Charest, M; Torres III, P; Charest, M

    2008-05-06

    Optical streak cameras are used as primary diagnostics for a wide range of physics and laser experiments at facilities such as the National Ignition Facility (NIF). To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electrical components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases, the characterization data are applied to the raw data images to correct for the nonlinearities. In order to characterize an optical streak camera, a specific set of data is collected, where the response to defined inputs are recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, and temporal resolution from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information.

  7. Sweep devices for picosecond image-converter streak cameras

    International Nuclear Information System (INIS)

    Cunin, B.; Miehe, J.A.; Sipp, B.; Schelev, M.Ya.; Serduchenko, J.N.; Thebault, J.

    1979-01-01

    Four different sweep devices based on microwave tubes, avalanche transistors, krytrons, and laser-triggered spark gaps are treated in detail. These control circuits are developed for picosecond image-converter cameras and generate sweep pulses providing streak speeds in the range of 10 7 to 5x10 10 cm/sec with maximum time resolution better than 10 -12 sec. Special low-jitter triggering schemes reduce the jitter to less than 5x10 -11 sec. Some problems arising in the construction and matching of the sweep devices and image-streak tube are discussed. Comparative parameters of nanosecond switching elements are presented. The results described can be used by other authors involved in streak camera development

  8. Picosecond X-ray streak camera dynamic range measurement

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-15

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

  9. Design of neutron streak camera for fusion diagnostics

    International Nuclear Information System (INIS)

    Wang, C.L.; Kalibjian, R.; Singh, M.S.

    1982-06-01

    The D-T burn time for advanced laser-fusion targets is calculated to be very short, 2 . Each fission fragment leaving the cathode generates 400 secondary electrons that are all < 20 eV. These electrons are focussed to a point with an extractor and an anode, and are then purified with an electrostatic deflector. The electron beam is streaked and detected with the standard streak camera techniques. Careful shielding is needed for x-rays from the fusion target and general background. It appears that the neutron streak camera can be a viable and unique tool for studying temporal history of fusion burns in D-T plasmas of a few keV ion temperature

  10. Improvements in Off-Center Focusing in an X-ray Streak Camera

    International Nuclear Information System (INIS)

    McDonald, J W; Weber, F; Holder, J P; Bell, P M

    2003-01-01

    Due to the planar construction of present x-ray streak tubes significant off-center defocusing is observed in both static and dynamic images taken with one-dimensional resolution slits. Based on the streak tube geometry curved photocathodes with radii of curvature ranging from 3.5 to 18 inches have been fabricated. We report initial off-center focusing performance data on the evaluation of these ''improved'' photocathodes in an X-ray streak camera and an update on the theoretical simulations to predict the optimum cathode curvature

  11. A novel simultaneous streak and framing camera without principle errors

    Science.gov (United States)

    Jingzhen, L.; Fengshan, S.; Ningwen, L.; Xiangdong, G.; Bin, H.; Qingyang, W.; Hongyi, C.; Yi, C.; Xiaowei, L.

    2018-02-01

    A novel simultaneous streak and framing camera with continuous access, the perfect information of which is far more important for the exact interpretation and precise evaluation of many detonation events and shockwave phenomena, has been developed. The camera with the maximum imaging frequency of 2 × 106 fps and the maximum scanning velocity of 16.3 mm/μs has fine imaging properties which are the eigen resolution of over 40 lp/mm in the temporal direction and over 60 lp/mm in the spatial direction and the framing frequency principle error of zero for framing record, and the maximum time resolving power of 8 ns and the scanning velocity nonuniformity of 0.136%~-0.277% for streak record. The test data have verified the performance of the camera quantitatively. This camera, simultaneously gained frames and streak with parallax-free and identical time base, is characterized by the plane optical system at oblique incidence different from space system, the innovative camera obscura without principle errors, and the high velocity motor driven beryllium-like rotating mirror, made of high strength aluminum alloy with cellular lateral structure. Experiments demonstrate that the camera is very useful and reliable to take high quality pictures of the detonation events.

  12. Imacon 600 ultrafast streak camera evaluation

    International Nuclear Information System (INIS)

    Owen, T.C.; Coleman, L.W.

    1975-01-01

    The Imacon 600 has a number of designed in disadvantages for use as an ultrafast diagnostic instrument. The unit is physically large (approximately 5' long) and uses an external power supply rack for the image intensifier. Water cooling is required for the intensifier; it is quiet but not conducive to portability. There is no interlock on the cooling water. The camera does have several switch selectable sweep speeds. This is desirable if one is working with both slow and fast events. The camera can be run in a framing mode. (MOW)

  13. Improved approach to characterizing and presenting streak camera performance

    International Nuclear Information System (INIS)

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

    1985-01-01

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  15. Reliable and Repeatable Characterization of Optical Streak Cameras

    International Nuclear Information System (INIS)

    Michael R. Charest, Peter Torres III, Christopher Silbernagel

    2008-01-01

    Optical streak cameras are used as primary diagnostics for a wide range of physics and laser performance verification experiments at the National Ignition Facility (NIF). To meet the strict accuracy requirements needed for these experiments, the systematic nonlinearities of the streak cameras (attributed to nonlinearities in the optical and electronic components that make up the streak camera system) must be characterized. In some cases the characterization information is used as a guide to help determine how experiment data should be taken. In other cases the characterization data is used to 'correct' data images, to remove some of the nonlinearities. In order to obtain these camera characterizations, a specific data set is collected where the response to specific known inputs is recorded. A set of analysis software routines has been developed to extract information such as spatial resolution, dynamic range, temporal resolution, etc., from this data set. The routines are highly automated, requiring very little user input and thus provide very reliable and repeatable results that are not subject to interpretation. An emphasis on quality control has been placed on these routines due to the high importance of the camera characterization information

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

    Science.gov (United States)

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

    2010-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, M. J.; Upadhyay, J.; Deshpande, P. P.; Sharma, M. L.; Navathe, C. P. [Laser Electronics Support Division, RRCAT, Indore 452013 (India)

    2010-08-15

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

  18. Microprocessor-controlled wide-range streak camera

    Science.gov (United States)

    Lewis, Amy E.; Hollabaugh, Craig

    2006-08-01

    Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera's user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.

  19. Microprocessor-controlled, wide-range streak camera

    International Nuclear Information System (INIS)

    Amy E. Lewis; Craig Hollabaugh

    2006-01-01

    Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera's user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized

  20. Microprocessor-controlled, wide-range streak camera

    Energy Technology Data Exchange (ETDEWEB)

    Amy E. Lewis, Craig Hollabaugh

    2006-09-01

    Bechtel Nevada/NSTec recently announced deployment of their fifth generation streak camera. This camera incorporates many advanced features beyond those currently available for streak cameras. The arc-resistant driver includes a trigger lockout mechanism, actively monitors input trigger levels, and incorporates a high-voltage fault interrupter for user safety and tube protection. The camera is completely modular and may deflect over a variable full-sweep time of 15 nanoseconds to 500 microseconds. The camera design is compatible with both large- and small-format commercial tubes from several vendors. The embedded microprocessor offers Ethernet connectivity, and XML [extensible markup language]-based configuration management with non-volatile parameter storage using flash-based storage media. The camera’s user interface is platform-independent (Microsoft Windows, Unix, Linux, Macintosh OSX) and is accessible using an AJAX [asynchronous Javascript and XML]-equipped modem browser, such as Internet Explorer 6, Firefox, or Safari. User interface operation requires no installation of client software or browser plug-in technology. Automation software can also access the camera configuration and control using HTTP [hypertext transfer protocol]. The software architecture supports multiple-simultaneous clients, multiple cameras, and multiple module access with a standard browser. The entire user interface can be customized.

  1. rf streak camera based ultrafast relativistic electron diffraction.

    Science.gov (United States)

    Musumeci, P; Moody, J T; Scoby, C M; Gutierrez, M S; Tran, T

    2009-01-01

    We theoretically and experimentally investigate the possibility of using a rf streak camera to time resolve in a single shot structural changes at the sub-100 fs time scale via relativistic electron diffraction. We experimentally tested this novel concept at the UCLA Pegasus rf photoinjector. Time-resolved diffraction patterns from thin Al foil are recorded. Averaging over 50 shots is required in order to get statistics sufficient to uncover a variation in time of the diffraction patterns. In the absence of an external pump laser, this is explained as due to the energy chirp on the beam out of the electron gun. With further improvements to the electron source, rf streak camera based ultrafast electron diffraction has the potential to yield truly single shot measurements of ultrafast processes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-25

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

  3. Characterization of X-ray streak cameras for use on Nova

    International Nuclear Information System (INIS)

    Kalantar, D.H.; Bell, P.M.; Costa, R.L.; Hammel, B.A.; Landen, O.L.; Orzechowski, T.J.; Hares, J.D.; Dymoke-Bradshaw, A.K.L.

    1996-09-01

    There are many different types of measurements that require a continuous time history of x-ray emission that can be provided with an x-ray streak camera. In order to properly analyze the images that are recorded with the x-ray streak cameras operated on Nova, it is important to account for the streak characterization of each camera. We have performed a number of calibrations of the streak cameras both on the bench as well as with Nova disk target shots where we use a time modulated laser intensity profile (self-beating of the laser) on the target to generate an x-ray comb. We have measured the streak camera sweep direction and spatial offset, curvature of the electron optics, sweep rate, and magnification and resolution of the electron optics

  4. Fabry-Perot interferometry using an image-intensified rotating-mirror streak camera

    International Nuclear Information System (INIS)

    Seitz, W.L.; Stacy, H.L.

    1983-01-01

    A Fabry-Perot velocity interferometer system is described that uses a modified rotating mirror streak camera to recrod the dynamic fringe positions. A Los Alamos Model 72B rotating-mirror streak camera, equipped with a beryllium mirror, was modified to include a high aperture (f/2.5) relay lens and a 40-mm image-intensifier tube such that the image normally formed at the film plane of the streak camera is projected onto the intensifier tube. Fringe records for thin (0.13 mm) flyers driven by a small bridgewire detonator obtained with a Model C1155-01 Hamamatsu and Model 790 Imacon electronic streak cameras are compared with those obtained with the image-intensified rotating-mirror streak camera (I 2 RMC). Resolution comparisons indicate that the I 2 RMC gives better time resolution than either the Hamamatsu or the Imacon for total writing times of a few microseconds or longer

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

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

    International Nuclear Information System (INIS)

    Schuette, Bernd

    2011-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Schuette, Bernd

    2011-09-15

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

  8. Flat-field response and geometric distortion measurements of optical streak cameras

    International Nuclear Information System (INIS)

    Montgomery, D.S.; Drake, R.P.; Jones, B.A.; Wiedwald, J.D.

    1987-01-01

    To accurately measure pulse amplitude, shape, and relative time histories of optical signals with an optical streak camera, it is necessary to correct each recorded image for spatially-dependent gain nonuniformity and geometric distortion. Gain nonuniformities arise from sensitivity variations in the streak-tube photocathode, phosphor screen, image-intensifier tube, and image recording system. By using a 1.053-μm, long-pulse, high-power laser to generate a spatially and temporally uniform source as input to the streak camera, the combined effects of flat-field response and geometric distortion can be measured under the normal dynamic operation of cameras with S-1 photocathodes. Additionally, by using the same laser system to generate a train of short pulses that can be spatially modulated at the input of the streak camera, the authors can create a two-dimensional grid of equally-spaced pulses. This allows a dynamic measurement of the geometric distortion of the streak camera. The author discusses the techniques involved in performing these calibrations, present some of the measured results for LLNL optical streak cameras, and will discuss software methods to correct for these effects

  9. Compact streak camera for the shock study of solids by using the high-pressure gas gun

    Science.gov (United States)

    Nagayama, Kunihito; Mori, Yasuhito

    1993-01-01

    For the precise observation of high-speed impact phenomena, a compact high-speed streak camera recording system has been developed. The system consists of a high-pressure gas gun, a streak camera, and a long-pulse dye laser. The gas gun installed in our laboratory has a muzzle of 40 mm in diameter, and a launch tube of 2 m long. Projectile velocity is measured by the laser beam cut method. The gun is capable of accelerating a 27 g projectile up to 500 m/s, if helium gas is used as a driver. The system has been designed on the principal idea that the precise optical measurement methods developed in other areas of research can be applied to the gun study. The streak camera is 300 mm in diameter, with a rectangular rotating mirror which is driven by an air turbine spindle. The attainable streak velocity is 3 mm/microsecond(s) . The size of the camera is rather small aiming at the portability and economy. Therefore, the streak velocity is relatively slower than the fast cameras, but it is possible to use low-sensitivity but high-resolution film as a recording medium. We have also constructed a pulsed dye laser of 25 - 30 microsecond(s) in duration. The laser can be used as a light source of observation. The advantage for the use of the laser will be multi-fold, i.e., good directivity, almost single frequency, and so on. The feasibility of the system has been demonstrated by performing several experiments.

  10. Characterization results from several commercial soft X-ray streak cameras

    Science.gov (United States)

    Stradling, G. L.; Studebaker, J. K.; Cavailler, C.; Launspach, J.; Planes, J.

    The spatio-temporal performance of four soft X-ray streak cameras has been characterized. The objective in evaluating the performance capability of these instruments is to enable us to optimize experiment designs, to encourage quantitative analysis of streak data and to educate the ultra high speed photography and photonics community about the X-ray detector performance which is available. These measurements have been made collaboratively over the space of two years at the Forge pulsed X-ray source at Los Alamos and at the Ketjak laser facility an CEA Limeil-Valenton. The X-ray pulse lengths used for these measurements at these facilities were 150 psec and 50 psec respectively. The results are presented as dynamically-measured modulation transfer functions. Limiting temporal resolution values were also calculated. Emphasis is placed upon shot noise statistical limitations in the analysis of the data. Space charge repulsion in the streak tube limits the peak flux at ultra short experiments duration times. This limit results in a reduction of total signal and a decrease in signal to no ise ratio in the streak image. The four cameras perform well with 20 1p/mm resolution discernable in data from the French C650X, the Hadland X-Chron 540 and the Hamamatsu C1936X streak cameras. The Kentech X-ray streak camera has lower modulation and does not resolve below 10 1p/mm but has a longer photocathode.

  11. Lasers and laser applications. Imaging implosion dynamics: The x-ray pinhole/streak camera

    International Nuclear Information System (INIS)

    Attwood, D.T.

    1976-01-01

    A Livermore-developed x-ray-sensitive streak camera was combined with a unique x-ray pinhole camera to make dynamic photographs of laser-irradiated fusion target implosions. These photographs show x radiation emitted from the imploding shell during its 100-ps implosion; they are the first continuous observations of an imploding laser-driven fusion capsule. The diagnostic system has a time resolution of 15 ps and a spatial resolution of about 6 μm. Results agree very well with those predicted by our LASNEX calculations, confirming that the essential physics are correctly described in the code and providing further confidence in the soundness of this approach to inertial confinement fusion

  12. C.C.D. readout of a picosecond streak camera with an intensified C.C.D

    International Nuclear Information System (INIS)

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

    1984-08-01

    This paper deals with a digital streak camera readout device. The device consists in a low light level television camera made of a solid state C.C.D. array coupled to an image intensifier associated to a video-digitizer coupled to a micro-computer system. The streak camera images are picked-up as a video signal, digitized and stored. This system allows the fast recording and the automatic processing of the data provided by the streak tube

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

  14. Towards jitter free synchronization of synchroscan streak cameras by noisy periodic laser pulses

    International Nuclear Information System (INIS)

    Cunin, B.; Heisel, F.; Miehe, J.A.

    1991-01-01

    In connection with the parameters characterizing the phase noise in cw mode-locked lasers and under the employ of streak cameras operated by sinewave deflection, the timing capabilities of the measuring system for two commonly used synchronization techniques are discussed by stochastic description. Especially, the power spectrum of the sweep signal versus the laser phase noise is examined in detail. The theoretical results are used to interpret experimental observations recorded by means of actively and passively mode-locked lasers. One of the interesting applications of synchroscan operations to metrology is the determination of short-term instabilities of the oscillator on a time scale near to the period. (author) 12 refs.; 3 figs

  15. Optical Comb Generation for Streak Camera Calibration for Inertial Confinement Fusion Experiments

    International Nuclear Information System (INIS)

    Ronald Justin; Terence Davies; Frans Janson; Bruce Marshall; Perry Bell; Daniel Kalantar; Joseph Kimbrough; Stephen Vernon; Oliver Sweningsen

    2008-01-01

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is coming on-line to support physics experimentation for the U.S. Department of Energy (DOE) programs in Inertial Confinement Fusion (ICF) and Stockpile Stewardship (SS). Optical streak cameras are an integral part of the experimental diagnostics instrumentation at NIF. To accurately reduce streak camera data a highly accurate temporal calibration is required. This article describes a technique for simultaneously generating a precise +/- 2 ps optical marker pulse (fiducial reference) and trains of precisely timed, short-duration optical pulses (so-called 'comb' pulse trains) that are suitable for the timing calibrations. These optical pulse generators are used with the LLNL optical streak cameras. They are small, portable light sources that, in the comb mode, produce a series of temporally short, uniformly spaced optical pulses, using a laser diode source. Comb generators have been produced with pulse-train repetition rates up to 10 GHz at 780 nm, and somewhat lower frequencies at 664 nm. Individual pulses can be as short as 25-ps FWHM. Signal output is via a fiber-optic connector on the front panel of the generator box. The optical signal is transported from comb generator to streak camera through multi-mode, graded-index optical fiber

  16. Streak camera measurements of laser pulse temporal dispersion in short graded-index optical fibers

    International Nuclear Information System (INIS)

    Lerche, R.A.; Phillips, G.E.

    1981-01-01

    Streak camera measurements were used to determine temporal dispersion in short (5 to 30 meter) graded-index optical fibers. Results show that 50-ps, 1.06-μm and 0.53-μm laser pulses can be propagated without significant dispersion when care is taken to prevent propagation of energy in fiber cladding modes

  17. Ultrafast streak and framing technique for the observation of laser driven shock waves in transparent solid targets

    International Nuclear Information System (INIS)

    Van Kessel, C.G.M.; Sachsenmaier, P.; Sigel, R.

    1975-01-01

    Shock waves driven by laser ablation in plane transparent plexiglass and solid hydrogen targets have been observed with streak and framing techniques using a high speed image converter camera, and a dye laser as a light source. The framing pictures have been made by mode locking the dye laser and using a wide streak slit. In both materials a growing hemispherical shock wave is observed with the maximum velocity at the onset of laser radiation. (author)

  18. Image-converter streak cameras with very high gain

    International Nuclear Information System (INIS)

    1975-01-01

    A new camera is described with slit scanning and very high photonic gain (G=5000). Development of the technology of tubes and microchannel plates has enabled integration of such an amplifying element in an image converter tube which does away with the couplings and the intermediary electron-photon-electron conversions of the classical converter systems having external amplification. It is thus possible to obtain equal or superior performance while retaining considerable gain for the camera, great compactness, great flexibility in use, and easy handling. (author)

  19. Commissioning of the advanced light source dual-axis streak camera

    International Nuclear Information System (INIS)

    Hinkson, J.; Keller, R.; Byrd, J.

    1997-05-01

    A dual-axis camera, Hamamatsu model C5680, has been installed on the Advanced Light Source photon-diagnostics beam-line to investigate electron-beam parameters. During its commissioning process, the camera has been used to measure single-bunch length vs. current, relative bunch charge in adjacent RF buckets, and bunchphase stability. In this paper the authors describe the visible-light branch of the diagnostics beam-line, the streak-camera installation, and the timing electronics. They will show graphical results of beam measurements taken during a variety of accelerator conditions

  20. X-ray streak and framing camera techniques

    International Nuclear Information System (INIS)

    Coleman, L.W.; Attwood, D.T.

    1975-01-01

    This paper reviews recent developments and applications of ultrafast diagnostic techniques for x-ray measurements. These techniques, based on applications of image converter devices, are already capable of significantly important resolution capabilities. Techniques capable of time resolution in the sub-nanosecond regime are being considered. Mechanical cameras are excluded from considerations as are devices using phosphors or fluors as x-ray converters

  1. Temporal resolution limit estimation of x-ray streak cameras using a CsI photocathode

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang; Gu, Li; Zong, Fangke; Zhang, Jingjin; Yang, Qinlao, E-mail: qlyang@szu.edu.cn [Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Institute of Optoelectronics, Shenzhen University, Shenzhen 518060 (China)

    2015-08-28

    A Monte Carlo model is developed and implemented to calculate the characteristics of x-ray induced secondary electron (SE) emission from a CsI photocathode used in an x-ray streak camera. Time distributions of emitted SEs are investigated with an incident x-ray energy range from 1 to 30 keV and a CsI thickness range from 100 to 1000 nm. Simulation results indicate that SE time distribution curves have little dependence on the incident x-ray energy and CsI thickness. The calculated time dispersion within the CsI photocathode is about 70 fs, which should be the temporal resolution limit of x-ray streak cameras that use CsI as the photocathode material.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-01

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

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

    International Nuclear Information System (INIS)

    Pei, Chengquan; Wu, Shengli; Tian, Jinshou; Liu, Zhen; Fang, Yuman; Gao, Guilong; Liang, Lingliang; Wen, Wenlong

    2015-01-01

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

  4. A sampling ultra-high-speed streak camera based on the use of a unique photomultiplier

    International Nuclear Information System (INIS)

    Marode, Emmanuel

    An apparatus reproducing the ''streak'' mode of a high-speed camera is proposed for the case of a slit AB whose variations in luminosity are repetitive. A photomultiplier, analysing the object AB point by point, and a still camera, photographing a slit fixed on the oscilloscope screen parallel to the sweep direction are placed on a mobile platform P. The movement of P assures a time-resolved analysis of AB. The resolution is of the order of 2.10 -9 s, and can be improved [fr

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

    Energy Technology Data Exchange (ETDEWEB)

    MacPhee, A. G., E-mail: macphee2@llnl.gov; Hatch, B. W.; Bell, P. M.; Bradley, D. K.; Datte, P. S.; Landen, O. L.; Palmer, N. E.; Piston, K. W.; Rekow, V. V. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); Dymoke-Bradshaw, A. K. L.; Hares, J. D. [Kentech Instruments Ltd., Isis Building, Howbery Park, Wallingford, Oxfordshire OX10 8BD (United Kingdom); Hassett, J. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627 (United States); Meadowcroft, A. L. [AWE Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Hilsabeck, T. J.; Kilkenny, J. D. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

    2016-11-15

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

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

    Science.gov (United States)

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

    2016-11-01

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

  7. Precise measurement of a subpicosecond electron single bunch by the femtosecond streak camera

    International Nuclear Information System (INIS)

    Uesaka, M.; Ueda, T.; Kozawa, T.; Kobayashi, T.

    1998-01-01

    Precise measurement of a subpicosecond electron single bunch by the femtosecond streak camera is presented. The subpicosecond electron single bunch of energy 35 MeV was generated by the achromatic magnetic pulse compressor at the S-band linear accelerator of nuclear engineering research laboratory (NERL), University of Tokyo. The electric charge per bunch and beam size are 0.5 nC and the horizontal and vertical beam sizes are 3.3 and 5.5 mm (full width at half maximum; FWHM), respectively. Pulse shape of the electron single bunch is measured via Cherenkov radiation emitted in air by the femtosecond streak camera. Optical parameters of the optical measurement system were optimized based on much experiment and numerical analysis in order to achieve a subpicosecond time resolution. By using the optimized optical measurement system, the subpicosecond pulse shape, its variation for the differents rf phases in the accelerating tube, the jitter of the total system and the correlation between measured streak images and calculated longitudinal phase space distributions were precisely evaluated. This measurement system is going to be utilized in several subpicosecond analyses for radiation physics and chemistry. (orig.)

  8. Cheap streak camera based on the LD-S-10 intensifier tube

    Science.gov (United States)

    Dashevsky, Boris E.; Krutik, Mikhail I.; Surovegin, Alexander L.

    1992-01-01

    Basic properties of a new streak camera and its test results are reported. To intensify images on its screen, we employed modular G1 tubes, the LD-A-1.0 and LD-A-0.33, enabling magnification of 1.0 and 0.33, respectively. If necessary, the LD-A-0.33 tube may be substituted by any other image intensifier of the LDA series, the choice to be determined by the size of the CCD matrix with fiber-optical windows. The reported camera employs a 12.5- mm-long CCD strip consisting of 1024 pixels, each 12 X 500 micrometers in size. Registered radiation was imaged on a 5 X 0.04 mm slit diaphragm tightly connected with the LD-S- 10 fiber-optical input window. Electrons escaping the cathode are accelerated in a 5 kV electric field and focused onto a phosphor screen covering a fiber-optical plate as they travel between deflection plates. Sensitivity of the latter was 18 V/mm, which implies that the total deflecting voltage was 720 V per 40 mm of the screen surface, since reversed-polarity scan pulses +360 V and -360 V were applied across the deflection plate. The streak camera provides full scan times over the screen of 15, 30, 50, 100, 250, and 500 ns. Timing of the electrically or optically driven camera was done using a 10 ns step-controlled-delay (0 - 500 ns) circuit.

  9. Synchronization of streak and framing camera measurements of an intense relativistic electron beam propagating through gas

    International Nuclear Information System (INIS)

    Weidman, D.J.; Murphy, D.P.; Myers, M.C.; Meger, R.A.

    1994-01-01

    The expansion of the radius of a 5 MeV, 20 kA, 40 ns electron beam from SuperIBEX during propagation through gas is being measured. The beam is generated, conditions, equilibrated, and then passed through a thin foil that produces Cherenkov light, which is recorded by a streak camera. At a second location, the beam hits another Cherenkov emitter, which is viewed by a framing camera. Measurements at these two locations can provide a time-resolved measure of the beam expansion. The two measurements, however, must be synchronized with each other, because the beam radius is not constant throughout the pulse due to variations in beam current and energy. To correlate the timing of the two diagnostics, several shots have been taken with both diagnostics viewing Cherenkov light from the same foil. Experimental measurements of the Cherenkov light from one foil viewed by both diagnostics will be presented to demonstrate the feasibility of correlating the diagnostics with each other. Streak camera data showing the optical fiducial, as well as the final correlation of the two diagnostics, will also be presented. Preliminary beam radius measurements from Cherenkov light measured at two locations will be shown

  10. Deflection system of a high-speed streak camera in the form of a delay line

    International Nuclear Information System (INIS)

    Korzhenevich, I.M.; Fel'dman, G.G.

    1993-01-01

    This paper presents an analysis of the operation of a meander deflection system, well-known in oscillography, when it is used to scan the image in a streak-camera tube. Effects that are specific to high-speed photography are considered. It is shown that such a deflection system imposes reduced requirements both on the steepness and on the duration of the linear leading edges of the pulses of the spark gaps that generate the sweep voltage. An example of the design of a meander deflection system whose sensitivity is a factor of two higher than for a conventional system is considered. 5 refs., 3 figs

  11. Fiber scintillator/streak camera detector for burn history measurement in inertial confinement fusion experiment

    International Nuclear Information System (INIS)

    Miyanaga, N.; Ohba, N.; Fujimoto, K.

    1997-01-01

    To measure the burn history in an inertial confinement fusion experiment, we have developed a new neutron detector based on plastic scintillation fibers. Twenty-five fiber scintillators were arranged in a geometry compensation configuration by which the time-of-flight difference of the neutrons is compensated by the transit time difference of light passing through the fibers. Each fiber scintillator is spliced individually to an ultraviolet optical fiber that is coupled to a streak camera. We have demonstrated a significant improvement of sensitivity compared with the usual bulk scintillator coupled to a bundle of the same ultraviolet fibers. copyright 1997 American Institute of Physics

  12. Development and performance test of picosecond pulse x-ray excited streak camera system for scintillator characterization

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Yoshikawa, Akira

    2010-01-01

    To observe time and wavelength-resolved scintillation events, picosecond pulse X-ray excited streak camera system is developed. The wavelength range spreads from vacuum ultraviolet (VUV) to near infrared region (110-900 nm) and the instrumental response function is around 80 ps. This work describes the principle of the newly developed instrument and the first performance test using BaF 2 single crystal scintillator. Core valence luminescence of BaF 2 peaking around 190 and 220 nm is clearly detected by our system, and the decay time turned out to be of 0.7 ns. These results are consistent with literature and confirm that our system properly works. (author)

  13. Picosecond streak camera diagnostics of CO2 laser-produced plasmas

    International Nuclear Information System (INIS)

    Jaanimagi, P.A.; Marjoribanks, R.S.; Sancton, R.W.; Enright, G.D.; Richardson, M.C.

    1979-01-01

    The interaction of intense laser radiation with solid targets is currently of considerable interest in laser fusion studies. Its understanding requires temporal knowledge of both laser and plasma parameters on a picosecond time scale. In this paper we describe the progress we have recently made in analysing, with picosecond time resolution, various features of intense nanosecond CO 2 laser pulse interaction experiments. An infrared upconversion scheme, having linear response and <20 ps temporal resolution, has been utilized to characterise the 10 μm laser pulse. Various features of the interaction have been studied with the aid of picosecond IR and x-ray streak cameras. These include the temporal and spatial characteristics of high harmonic emission from the plasma, and the temporal development of the x-ray continuum spectrum. (author)

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

    International Nuclear Information System (INIS)

    Labaria, George R.; Warrick, Abbie L.; Celliers, Peter M.; Kalantar, Daniel H.

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-12

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

  16. Streak-Camera Measurements with High Currents in PEP-II and Variable Optics in SPEAR3

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Weixeng; Fisher, Alan, a Corbett, Jeff; /SLAC

    2008-06-05

    A dual-axis, synchroscan streak camera was used to measure longitudinal bunch profiles in three storage rings at SLAC: the PEP-II low- and high-energy rings, and SPEAR3. At high currents, both PEP rings exhibit a transient synchronous-phase shift along the bunch train due to RF-cavity beam loading. Bunch length and profile asymmetry were measured along the train for a range of beam currents. To avoid the noise inherent in a dual-axis sweep, we accumulated single-axis synchroscan images while applying a 50-ns gate to the microchannel plate. To improve the extinction ratio, an upstream mirror pivoting at 1 kHz was synchronized with the 2kHz MCP gate to deflect light from other bunches off the photocathode. Bunch length was also measured on the HER as a function of beam energy. For SPEAR3 we measured bunch length as a function of single-bunch current for several lattices: achromatic, low-emittance and low momentum compaction. In the first two cases, resistive and reactive impedance components can be extracted from the longitudinal bunch profiles. In the low-alpha configurations, we observed natural bunch lengths approaching the camera resolution, requiring special care to remove instrumental effects, and saw evidence of periodic bursting.

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

    CERN Document Server

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

    2002-01-01

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

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

    International Nuclear Information System (INIS)

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

    1990-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Furuya, Yuki, E-mail: f.yuki@mail.tagen.tohoku.ac.j [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Kamada, Kei [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kawaguchi, Noriaki [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Research and Development Division, Tokuyama., Co. Ltd., ICR-Building, Minamiyoshinari, Aoba-ku, Sendai (Japan); Ishizu, Sumito [Research and Development Division, Tokuyama., Co. Ltd., ICR-Building, Minamiyoshinari, Aoba-ku, Sendai (Japan); Uchiyama, Koro; Mori, Kuniyoshi [Hamamatsu Photonics K.K., 325-6, Sunayama-cho, Naka-ku, Hamamatsu, Shizuoka 430-8587 (Japan); Kitano, Ken [Vacuum and Optical Instruments, 2-18-18 Shimomaruko, Ota, Tokyo 146-0092 (Japan); Nikl, Martin [Institute of Physics ASCR, Cukrovarnicka 10, Prague 6, 162-53 (Czech Republic); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); NICHe, Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2011-04-01

    To design new scintillating materials, it is very important to understand detailed information about the events, which occurred during the excitation and emission processes under the ionizing radiation excitation. We developed a streak camera system equipped with picosecond pulsed X-ray source to observe time- and wavelength-resolved scintillation events. In this report, we test the performance of this new system using several types of scintillators including bulk oxide/halide crystals, transparent ceramics, plastics and powders. For all samples, the results were consistent with those reported previously. The results demonstrated that the developed system is suitable for evaluation of the scintillation properties.

  20. StreakDet data processing and analysis pipeline for space debris optical observations

    Science.gov (United States)

    Virtanen, Jenni; Flohrer, Tim; Muinonen, Karri; Granvik, Mikael; Torppa, Johanna; Poikonen, Jonne; Lehti, Jussi; Santti, Tero; Komulainen, Tuomo; Naranen, Jyri

    We describe a novel data processing and analysis pipeline for optical observations of space debris. The monitoring of space object populations requires reliable acquisition of observational data, to support the development and validation of space debris environment models, the build-up and maintenance of a catalogue of orbital elements. In addition, data is needed for the assessment of conjunction events and for the support of contingency situations or launches. The currently available, mature image processing algorithms for detection and astrometric reduction of optical data cover objects that cross the sensor field-of-view comparably slowly, and within a rather narrow, predefined range of angular velocities. By applying specific tracking techniques, the objects appear point-like or as short trails in the exposures. However, the general survey scenario is always a “track before detect” problem, resulting in streaks, i.e., object trails of arbitrary lengths, in the images. The scope of the ESA-funded StreakDet (Streak detection and astrometric reduction) project is to investigate solutions for detecting and reducing streaks from optical images, particularly in the low signal-to-noise ratio (SNR) domain, where algorithms are not readily available yet. For long streaks, the challenge is to extract precise position information and related registered epochs with sufficient precision. Although some considerations for low-SNR processing of streak-like features are available in the current image processing and computer vision literature, there is a need to discuss and compare these approaches for space debris analysis, in order to develop and evaluate prototype implementations. In the StreakDet project, we develop algorithms applicable to single images (as compared to consecutive frames of the same field) obtained with any observing scenario, including space-based surveys and both low- and high-altitude populations. The proposed processing pipeline starts from the

  1. X-ray streak-camera study of the dynamics of laser-imploded microballoons

    International Nuclear Information System (INIS)

    Key, M.H.; Lamb, M.J.; Lewis, C.L.S.; Moore, A.; Evans, R.G.

    1979-01-01

    The time and space development of the x-ray emission from the irradiated target surface and the implosion core in laser-compressed glass microballoons is recorded by x-ray streak photography. The experimental variation of implosion time with target mass and laser energy is considered and compared with computer modeling of the implosion

  2. Streak electronic camera with slow-scanning storage tube used in the field of high-speed cineradiography

    International Nuclear Information System (INIS)

    Marilleau, J.; Bonnet, L.; Garcin, G.; Guix, R.; Loichot, R.

    The cineradiographic machine designed for measurements in the field of detonics consists of a linear accelerator associated with a braking target, a scintillator and a remote controlled electronic camera. The quantum factor of X-ray detection and the energetic efficiency of the scintillator are given. The electronic camera is built upon a deflection-converter tube (RCA C. 73 435 AJ) coupled by optical fibres to a photosensitive storage tube (TH-CSF Esicon) used in a slow-scanning process with electronic recording of the information. The different parts of the device are described. Some capabilities such as data processing numerical outputs, measurements and display are outlined. A streak cineradiogram of a typical implosion experiment is given [fr

  3. Aluminum-coated optical fibers as efficient infrared timing fiducial photocathodes for synchronizing x-ray streak cameras

    International Nuclear Information System (INIS)

    Koch, J.A.; MacGowan, B.J.

    1991-01-01

    The timing fiducial system at the Nova Two-Beam Facility allows time-resolved x-ray and optical streak camera data from laser-produced plasmas to be synchronized to within 30 ps. In this system, an Al-coated optical fiber is inserted into an aperture in the cathode plate of each streak camera. The coating acts as a photocathode for a low-energy pulse of 1ω (λ = 1.054 μm) light which is synchronized to the main Nova beam. The use of the fundamental (1ω) for this fiducial pulse has been found to offer significant advantages over the use of the 2ω second harmonic (λ = 0.53 μm). These advantages include brighter signals, greater reliability, and a higher relative damage threshold, allowing routine use without fiber replacement. The operation of the system is described, and experimental data and interpretations are discussed which suggest that the electron production in the Al film is due to thermionic emission. The results of detailed numerical simulations of the relevant thermal processes, undertaken to model the response of the coated fiber to 1ω laser pulses, are also presented, which give qualitative agreement with experimental data. Quantitative discrepancies between the modeling results and the experimental data are discussed, and suggestions for further research are given

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-31

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

  5. Realization of an optical multi and mono-channel analyzer, associated to a streak camera. Application to metrology of picosecond low intensity luminous pulses

    International Nuclear Information System (INIS)

    Roth, J.M.

    1985-02-01

    An electronic system including a low light level television tube (Nocticon) to digitize images from streak cameras is studied and realized. Performances (sensibility, signal-to-noise ratio) are studied and compared with a multi-channel analyzer using a linear network of photodiodes. It is applied to duration and amplitude measurement of short luminous pulses [fr

  6. Identification and Removal of High Frequency Temporal Noise in a Nd:YAG Macro-Pulse Laser Assisted with a Diagnostic Streak Camera

    International Nuclear Information System (INIS)

    Kent Marlett; Ke-Xun Sun

    2004-01-01

    This paper discusses the use of a reference streak camera (SC) to diagnose laser performance and guide modifications to remove high frequency noise from Bechtel Nevada's long-pulse laser. The upgraded laser exhibits less than 0.1% high frequency noise in cumulative spectra, exceeding National Ignition Facility (NIF) calibration specifications. Inertial Confinement Fusion (ICF) experiments require full characterization of streak cameras over a wide range of sweep speeds (10 ns to 480 ns). This paradigm of metrology poses stringent spectral requirements on the laser source for streak camera calibration. Recently, Bechtel Nevada worked with a laser vendor to develop a high performance, multi-wavelength Nd:YAG laser to meet NIF calibration requirements. For a typical NIF streak camera with a 4096 x 4096 pixel CCD, the flat field calibration at 30 ns requires a smooth laser spectrum over 33 MHz to 68 GHz. Streak cameras are the appropriate instrumentation for measuring laser amplitude noise at these very high frequencies since the upper end spectral content is beyond the frequency response of typical optoelectronic detectors for a single shot pulse. The SC was used to measure a similar laser at its second harmonic wavelength (532 nm), to establish baseline spectra for testing signal analysis algorithms. The SC was then used to measure the new custom calibration laser. In both spatial-temporal measurements and cumulative spectra, 6-8 GHz oscillations were identified. The oscillations were found to be caused by inter-surface reflections between amplifiers. Additional variations in the SC spectral data were found to result from temperature instabilities in the seeding laser. Based on these findings, laser upgrades were made to remove the high frequency noise from the laser output

  7. X-ray imaging of JET. A design study for a streak camera application

    International Nuclear Information System (INIS)

    Bateman, J.E.; Hobby, M.G.

    1980-03-01

    A single dimensional imaging system is proposed which will image a strip of the JET plasma up to 320 times per shot with a time resolution of better than 50 μs using the bremsstrahlung X-rays. The images are obtained by means of a pinhole camera followed by an X-ray image intensifier system the output of which is in turn digitised by a photodiode array. The information is stored digitally in a fast memory and is immediately available for display or analysis. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-07-01

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

  9. Initial tests of the dual-sweep streak camera system planned for APS particle-beam diagnostics

    International Nuclear Information System (INIS)

    Lumpkin, A.; Yang, B.; Gai, W.; Cieslik, W.

    1995-01-01

    Initial tests of a dual-sweep streak system planned for use on the Advanced Photon Source (APS) have been performed using assets of the Argonne Wakefield Accelerator (AWA) facility. The short light pulses from the photoelectric injector drive laser in both the visible (λ=496 nm, Δt∼1.5 ps (FWHM)), and the ultraviolet (λ=248 nm, Δt∼5 ps (FWHM)) were used. Both a UV-visible S20 photocathode streak tube and a UV-to-x-ray Au photocathode streak tube were tested. Calibration data with an etalon were also obtained. A sample of dual-sweep streak data using optical synchrotron radiation on the APS injector synchrotron is also presented

  10. Observations of the Perseids 2013 using SPOSH cameras

    Science.gov (United States)

    Margonis, A.; Elgner, S.; Christou, A.; Oberst, J.; Flohrer, J.

    2013-09-01

    Earth is constantly bombard by debris, most of which disintegrates in the upper atmosphere. The collision of a dust particle, having a mass of approximately 1g or larger, with the Earth's atmosphere results into a visible streak of light in the night sky, called meteor. Comets produce new meteoroids each time they come close to the Sun due to sublimation processes. These fresh particles are moving around the Sun in orbits similar to their parent comet forming meteoroid streams. For this reason, the intersection of Earth's orbital path with different comets, gives rise to anumber of meteor showers throughout the year. The Perseids are one of the most prominent annual meteor showers occurring every summer, having its origin in Halley-type comet 109P/Swift-Tuttle. The dense core of this stream passes Earth's orbit on the 12th of August when more than 100 meteors per hour can been seen by a single observer under ideal conditions. The Technical University of Berlin (TUB) and the German Aerospace Center (DLR) together with the Armagh observatory organize meteor campaigns every summer observing the activity of the Perseids meteor shower. The observations are carried out using the Smart Panoramic Optical Sensor Head (SPOSH) camera system [2] which has been developed by DLR and Jena-Optronik GmbH under an ESA/ESTEC contract. The camera was designed to image faint, short-lived phenomena on dark planetary hemispheres. The camera is equipped with a highly sensitive back-illuminated CCD chip having a pixel resolution of 1024x1024. The custom-made fish-eye lens offers a 120°x120° field-of-view (168° over the diagonal) making the monitoring of nearly the whole night sky possible (Fig. 1). This year the observations will take place between 3rd and 10th of August to cover the meteor activity of the Perseids just before their maximum. The SPOSH cameras will be deployed at two remote sites located in high altitudes in the Greek Peloponnese peninsula. The baseline of ∼50km

  11. Large-grazing-angle, multi-image Kirkpatrick-Baez microscope as the front end to a high-resolution streak camera for OMEGA

    International Nuclear Information System (INIS)

    Gotchev, O.V.; Hayes, L.J.; Jaanimagi, P.A.; Knauer, J.P.; Marshall, F.J.; Meyerhofer, D.D.

    2003-01-01

    A high-resolution x-ray microscope with a large grazing angle has been developed, characterized, and fielded at the Laboratory for Laser Energetics. It increases the sensitivity and spatial resolution in planar direct-drive hydrodynamic stability experiments, relevant to inertial confinement fusion research. It has been designed to work as the optical front end of the PJX - a high-current, high-dynamic-range x-ray streak camera. Optical design optimization, results from numerical ray tracing, mirror-coating choice, and characterization have been described previously [O. V. Gotchev, et al., Rev. Sci. Instrum. 74, 2178 (2003)]. This work highlights the optics' unique mechanical design and flexibility and considers certain applications that benefit from it. Characterization of the microscope's resolution in terms of its modulation transfer function over the field of view is shown. Recent results from hydrodynamic stability experiments, diagnosed with the optic and the PJX, are provided to confirm the microscope's advantages as a high-resolution, high-throughput x-ray optical front end for streaked imaging

  12. Large-Grazing-Angle, Multi-Image Kirkpatrick-Baez Microscope as the Front End to a High-Resolution Streak Camera for OMEGA

    International Nuclear Information System (INIS)

    Gotchev, O.V.; Hayes, L.J.; Jaanimagi, P.A.; Knauer, J.P.; Marshall, F.J.; Meyerhofer, D. D.

    2003-01-01

    (B204)A new, high-resolution x-ray microscope with a large grazing angle has been developed, characterized, and fielded at the Laboratory for Laser Energetics. It increases the sensitivity and spatial resolution in planar direct-drive hydrodynamic stability experiments, relevant to inertial confinement fusion (ICF) research. It has been designed to work as the optical front end of the PJX-a high-current, high-dynamic-range x-ray streak camera. Optical design optimization, results from numerical ray tracing, mirror-coating choice, and characterization have been described previously [O. V. Gotchev, et al./Rev. Sci. Instrum. 74, 2178 (2003)]. This work highlights the optics' unique mechanical design and flexibility and considers certain applications that benefit from it. Characterization of the microscope's resolution in terms of its modulation transfer function (MTF) over the field of view is shown. Recent results from hydrodynamic stability experiments, diagnosed with the optic and the PJX, are provided to confirm the microscope's advantages as a high-resolution, high-throughput x-ray optical front end for streaked imaging

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

    Energy Technology Data Exchange (ETDEWEB)

    Fruehling, Ulrike

    2009-10-15

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

  14. A numerical algorithm to evaluate the transient response for a synchronous scanning streak camera using a time-domain Baum–Liu–Tesche equation

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Chengquan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); Tian, Jinshou [Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); Wu, Shengli, E-mail: slwu@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); He, Jiai [School of Computer and Communication, Lanzhou University of Technology, Lanzhou, Gansu 730050 (China); Liu, Zhen [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China)

    2016-10-01

    The transient response is of great influence on the electromagnetic compatibility of synchronous scanning streak cameras (SSSCs). In this paper we propose a numerical method to evaluate the transient response of the scanning deflection plate (SDP). First, we created a simplified circuit model for the SDP used in an SSSC, and then derived the Baum–Liu–Tesche (BLT) equation in the frequency domain. From the frequency-domain BLT equation, its transient counterpart was derived. These parameters, together with the transient-BLT equation, were used to compute the transient load voltage and load current, and then a novel numerical method to fulfill the continuity equation was used. Several numerical simulations were conducted to verify this proposed method. The computed results were then compared with transient responses obtained by a frequency-domain/fast Fourier transform (FFT) method, and the accordance was excellent for highly conducting cables. The benefit of deriving the BLT equation in the time domain is that it may be used with slight modifications to calculate the transient response and the error can be controlled by a computer program. The result showed that the transient voltage was up to 1000 V and the transient current was approximately 10 A, so some protective measures should be taken to improve the electromagnetic compatibility.

  15. A numerical algorithm to evaluate the transient response for a synchronous scanning streak camera using a time-domain Baum–Liu–Tesche equation

    International Nuclear Information System (INIS)

    Pei, Chengquan; Tian, Jinshou; Wu, Shengli; He, Jiai; Liu, Zhen

    2016-01-01

    The transient response is of great influence on the electromagnetic compatibility of synchronous scanning streak cameras (SSSCs). In this paper we propose a numerical method to evaluate the transient response of the scanning deflection plate (SDP). First, we created a simplified circuit model for the SDP used in an SSSC, and then derived the Baum–Liu–Tesche (BLT) equation in the frequency domain. From the frequency-domain BLT equation, its transient counterpart was derived. These parameters, together with the transient-BLT equation, were used to compute the transient load voltage and load current, and then a novel numerical method to fulfill the continuity equation was used. Several numerical simulations were conducted to verify this proposed method. The computed results were then compared with transient responses obtained by a frequency-domain/fast Fourier transform (FFT) method, and the accordance was excellent for highly conducting cables. The benefit of deriving the BLT equation in the time domain is that it may be used with slight modifications to calculate the transient response and the error can be controlled by a computer program. The result showed that the transient voltage was up to 1000 V and the transient current was approximately 10 A, so some protective measures should be taken to improve the electromagnetic compatibility.

  16. Streak tube development

    International Nuclear Information System (INIS)

    Hinrichs, C.K.; Estrella, R.M.

    1979-01-01

    A research program for the development of a high-speed, high-resolution streak image tube is described. This is one task in the development of a streak camera system with digital electronic readout, whose primary application is for diagnostics in underground nuclear testing. This program is concerned with the development of a high-resolution streak image tube compatible with x-ray input and electronic digital output. The tube must be capable of time resolution down to 100 psec and spatial resolution to provide greater than 1000 resolution elements across the cathode (much greater than presently available). Another objective is to develop the capability to make design changes in tube configurations to meet different experimental requirements. A demountable prototype streak tube was constructed, mounted on an optical bench, and placed in a vacuum system. Initial measurements of the tube resolution with an undeflected image show a resolution of 32 line pairs per millimeter over a cathode diameter of one inch, which is consistent with the predictions of the computer simulations. With the initial set of unoptmized deflection plates, the resolution pattern appeared to remain unchanged for static deflections of +- 1/2-inch, a total streak length of one inch, also consistent with the computer simulations. A passively mode-locked frequency-doubled dye laser is being developed as an ultraviolet pulsed light source to measure dynamic tube resolution during streaking. A sweep circuit to provide the deflection voltage in the prototype tube has been designed and constructed and provides a relatively linear ramp voltage with ramp durations adjustable between 10 and 1000 nsec

  17. Triton's streaks as windblown dust

    Science.gov (United States)

    Sagan, Carl; Chyba, Christopher

    1990-01-01

    Explanations for the surface streaks observed by Voyager 2 on Triton's southern hemisphere are discussed. It is shown that, despite Triton's tenuous atmosphere, low-cohesion dust trains with diameters of about 5 micron or less may be carried into suspension by aeolian surface shear stress, given expected geostrophic wind speeds of about 10 m/s. For geyser-like erupting dust plumes, it is shown that dust-settling time scales and expected wind velocities can produce streaks with length scales in good agreement with those of the streaks. Thus, both geyserlike eruptions or direct lifting by surface winds appear to be viable mechanisms for the origin of the streaks.

  18. A cooperative control algorithm for camera based observational systems.

    Energy Technology Data Exchange (ETDEWEB)

    Young, Joseph G.

    2012-01-01

    Over the last several years, there has been considerable growth in camera based observation systems for a variety of safety, scientific, and recreational applications. In order to improve the effectiveness of these systems, we frequently desire the ability to increase the number of observed objects, but solving this problem is not as simple as adding more cameras. Quite often, there are economic or physical restrictions that prevent us from adding additional cameras to the system. As a result, we require methods that coordinate the tracking of objects between multiple cameras in an optimal way. In order to accomplish this goal, we present a new cooperative control algorithm for a camera based observational system. Specifically, we present a receding horizon control where we model the underlying optimal control problem as a mixed integer linear program. The benefit of this design is that we can coordinate the actions between each camera while simultaneously respecting its kinematics. In addition, we further improve the quality of our solution by coupling our algorithm with a Kalman filter. Through this integration, we not only add a predictive component to our control, but we use the uncertainty estimates provided by the filter to encourage the system to periodically observe any outliers in the observed area. This combined approach allows us to intelligently observe the entire region of interest in an effective and thorough manner.

  19. Multislit streak photography for plasma dynamics studies

    International Nuclear Information System (INIS)

    Tou, T.Y.; Lee, S.

    1988-01-01

    A microscope slide with several transparent slits installed in a streak camera is used to record time-resolved two-dimensional information when a curved luminous plasma sheath traverses these slits. Applying this method to the plasma focus experiment, the axial run-down trajectory and the shapes of the plasma sheath at various moments can be obtained from a single streak photograph

  20. Observing bodies. Camera surveillance and the significance of the body.

    NARCIS (Netherlands)

    Dubbeld, L.

    2003-01-01

    At the most mundane level, CCTV observes bodies, and as such attaches great importance to the specific features of the human body. At the same time, however, bodies tend to disappear, as they are represented electronically by the camera monitors and, in the case of image recording, by the computer

  1. Observations of the Perseids 2012 using SPOSH cameras

    Science.gov (United States)

    Margonis, A.; Flohrer, J.; Christou, A.; Elgner, S.; Oberst, J.

    2012-09-01

    The Perseids are one of the most prominent annual meteor showers occurring every summer when the stream of dust particles, originating from Halley-type comet 109P/Swift-Tuttle, intersects the orbital path of the Earth. The dense core of this stream passes Earth's orbit on the 12th of August producing the maximum number of meteors. The Technical University of Berlin (TUB) and the German Aerospace Center (DLR) organize observing campaigns every summer monitoring the Perseids activity. The observations are carried out using the Smart Panoramic Optical Sensor Head (SPOSH) camera system [0]. The SPOSH camera has been developed by DLR and Jena-Optronik GmbH under an ESA/ESTEC contract and it is designed to image faint, short-lived phenomena on dark planetary hemispheres. The camera features a highly sensitive backilluminated 1024x1024 CCD chip and a high dynamic range of 14 bits. The custom-made fish-eye lens offers a 120°x120° field-of-view (168° over the diagonal). Figure 1: A meteor captured by the SPOSH cameras simultaneously during the last 2011 observing campaign in Greece. The horizon including surrounding mountains can be seen in the image corners as a result of the large FOV of the camera. The observations will be made on the Greek Peloponnese peninsula monitoring the post-peak activity of the Perseids during a one-week period around the August New Moon (14th to 21st). Two SPOSH cameras will be deployed in two remote sites in high altitudes for the triangulation of meteor trajectories captured at both stations simultaneously. The observations during this time interval will give us the possibility to study the poorly-observed postmaximum branch of the Perseid stream and compare the results with datasets from previous campaigns which covered different periods of this long-lived meteor shower. The acquired data will be processed using dedicated software for meteor data reduction developed at TUB and DLR. Assuming a successful campaign, statistics, trajectories

  2. Medium-sized aperture camera for Earth observation

    Science.gov (United States)

    Kim, Eugene D.; Choi, Young-Wan; Kang, Myung-Seok; Kim, Ee-Eul; Yang, Ho-Soon; Rasheed, Ad. Aziz Ad.; Arshad, Ahmad Sabirin

    2017-11-01

    Satrec Initiative and ATSB have been developing a medium-sized aperture camera (MAC) for an earth observation payload on a small satellite. Developed as a push-broom type high-resolution camera, the camera has one panchromatic and four multispectral channels. The panchromatic channel has 2.5m, and multispectral channels have 5m of ground sampling distances at a nominal altitude of 685km. The 300mm-aperture Cassegrain telescope contains two aspheric mirrors and two spherical correction lenses. With a philosophy of building a simple and cost-effective camera, the mirrors incorporate no light-weighting, and the linear CCDs are mounted on a single PCB with no beam splitters. MAC is the main payload of RazakSAT to be launched in 2005. RazakSAT is a 180kg satellite including MAC, designed to provide high-resolution imagery of 20km swath width on a near equatorial orbit (NEqO). The mission objective is to demonstrate the capability of a high-resolution remote sensing satellite system on a near equatorial orbit. This paper describes the overview of the MAC and RarakSAT programmes, and presents the current development status of MAC focusing on key optical aspects of Qualification Model.

  3. Development of the Earth Observation Camera of MIRIS

    Directory of Open Access Journals (Sweden)

    Dae-Hee Lee

    2011-09-01

    Full Text Available We have designed and manufactured the Earth observation camera (EOC of multi-purpose infrared imaging system (MIRIS. MIRIS is a main payload of the STSAT-3, which will be launched in late 2012. The main objective of the EOC is to test the operation of Korean IR technology in space, so we have designed the optical and mechanical system of the EOC to fit the IR detector system. We have assembled the flight model (FM of EOC and performed environment tests successfully. The EOC is now ready to be integrated into the satellite system waiting for operation in space, as planned.

  4. Multi‐angular observations of vegetation indices from UAV cameras

    DEFF Research Database (Denmark)

    Sobejano-Paz, Veronica; Wang, Sheng; Jakobsen, Jakob

    Unmanned aerial vehicles (UAVs) are found as an alternative to the classical manned aerial photogrammetry, which can be used to obtain environmental data or as a complementary solution to other methods (Nex and Remondino, 2014). Although UAVs have coverage limitations, they have better resolution...... (Berni et al., 2009), hyper spectral camera (Burkart et al., 2015) and photometric elevation mapping sensor (Shahbazi et al., 2015) among others. Therefore, UAVs can be used in many fields such as agriculture, forestry, archeology, architecture, environment and traffic monitoring (Nex and Remondino, 2014......). In this study, the UAV used is a hexacopter s900 equipped with a Global Positioning System (GPS) and two cameras; a digital RGB photo camera and a multispectral camera (MCA), with a resolution of 5472 x 3648 pixels and 1280 x 1024 pixels, respectively. In terms of applications, traditional methods using...

  5. Wind Streaks on Earth; Exploration and Interpretation

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

    Austin, Susan Eudy

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

  7. An evaluation of video cameras for collecting observational data on sanctuary-housed chimpanzees (Pan troglodytes).

    Science.gov (United States)

    Hansen, Bethany K; Fultz, Amy L; Hopper, Lydia M; Ross, Stephen R

    2018-05-01

    Video cameras are increasingly being used to monitor captive animals in zoo, laboratory, and agricultural settings. This technology may also be useful in sanctuaries with large and/or complex enclosures. However, the cost of camera equipment and a lack of formal evaluations regarding the use of cameras in sanctuary settings make it challenging for facilities to decide whether and how to implement this technology. To address this, we evaluated the feasibility of using a video camera system to monitor chimpanzees at Chimp Haven. We viewed a group of resident chimpanzees in a large forested enclosure and compared observations collected in person and with remote video cameras. We found that via camera, the observer viewed fewer chimpanzees in some outdoor locations (GLMM post hoc test: est. = 1.4503, SE = 0.1457, Z = 9.951, p sanctuaries to facilitate animal care and observational research. © 2018 Wiley Periodicals, Inc.

  8. Picosecond x-ray streak camera studies

    International Nuclear Information System (INIS)

    Kasyanov, Yu.S.; Malyutin, A.A.; Richardson, M.C.; Chevokin, V.K.

    1975-01-01

    Some initial results of direct measurement of picosecond x-ray emission from laser-produced plasmas are presented. A PIM-UMI 93 image converter tube, incorporating an x-ray sensitive photocathode, linear deflection, and three stages of image amplification was used to analyse the x-ray radiation emanating from plasmas produced from solid Ti targets by single high-intensity picosecond laser pulses. From such plasmas, the x-ray emission typically persisted for times of 60psec. However, it is shown that this detection system should be capable of resolving x-ray phenomena of much shorter duration. (author)

  9. Observation of Possible Lava Tube Skylights by SELENE cameras

    Science.gov (United States)

    Haruyama, Junichi; Hiesinger, Harald; van der Bogert, Carolyn

    We have discovered three deep hole-structures on the Moon in the Terrain Camera and Multi-band Imager on the SELENE. These holes are large depth to diameter ratios: Marius Hills Hole (MHH) is 65 m in diameter and 88-90 m in depth, Mare Tranquillitatis Hole (MTH) is 120 x 110 m in diameter and 180 m in depth, and Mare Ingenii Hole (MIH) is 140 x 110 m in diameter and deeper than 90 m. No volcanic material from the holes nor dike-relating pit craters is seen around the holes. They are possible lava tube skylights. These holes and possibly connected tubes have a lot of scientific interests and high potentialities as lunar bases.

  10. Dust-gas interaction deduced from Halley multicolour camera observations

    International Nuclear Information System (INIS)

    Huebner, W.F.; Delamere, W.A.; Keller, H.U.; Reitsema, H.J.; Schmidt, H.U.; Whipple, F.L.; Wilhelm, K.

    1986-01-01

    The dust and gas productions of Comet Halley were measured by the dust counter and the mass spectrometers on the Giotto spacecraft. These instruments give only little information about the spatial asymmetry of the activity. The asymmetry in the dust production is clearly evident from the dust jets seen in the Halley Multicolour Camera images. Since the dust is entrained by the gas, production must be similarly asymmetric. The intensity profiles along and across several dust jets are related to their source regions on the nucleus. Properties of the dust jets are investigated. A few compact, but highly active source regions on the nucleus produce most of the visible dust and can account for most of the gas produced by the comet. 2 refs

  11. Multi-spectral CCD camera system for ocean water color and seacoast observation

    Science.gov (United States)

    Zhu, Min; Chen, Shiping; Wu, Yanlin; Huang, Qiaolin; Jin, Weiqi

    2001-10-01

    One of the earth observing instruments on HY-1 Satellite which will be launched in 2001, the multi-spectral CCD camera system, is developed by Beijing Institute of Space Mechanics & Electricity (BISME), Chinese Academy of Space Technology (CAST). In 798 km orbit, the system can provide images with 250 m ground resolution and a swath of 500 km. It is mainly used for coast zone dynamic mapping and oceanic watercolor monitoring, which include the pollution of offshore and coast zone, plant cover, watercolor, ice, terrain underwater, suspended sediment, mudflat, soil and vapor gross. The multi- spectral camera system is composed of four monocolor CCD cameras, which are line array-based, 'push-broom' scanning cameras, and responding for four spectral bands. The camera system adapts view field registration; that is, each camera scans the same region at the same moment. Each of them contains optics, focal plane assembly, electrical circuit, installation structure, calibration system, thermal control and so on. The primary features on the camera system are: (1) Offset of the central wavelength is better than 5 nm; (2) Degree of polarization is less than 0.5%; (3) Signal-to-noise ratio is about 1000; (4) Dynamic range is better than 2000:1; (5) Registration precision is better than 0.3 pixel; (6) Quantization value is 12 bit.

  12. HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY 2nd QUARTER 2010 MILESTONE REPORT. Develop the theory connecting pyrometer and streak camera spectrometer data to the material properties of beam heated targets and compare to the data

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  13. Streaking tremor in Cascadia

    Science.gov (United States)

    Vidale, J. E.; Ghosh, A.; Sweet, J. R.; Creager, K. C.; Wech, A.; Houston, H.

    2009-12-01

    Details of tremor deep in subduction zones is damnably difficult to glimpse because of the lack of crisp initial arrivals, low waveform coherence, uncertain focal mechanisms, and the probability of simultaneous activity across extended regions. Yet such details hold out the best hope to illuminate the unknown mechanisms underlying episodic tremor and slip. Attacking this problem with brute force, we pointed a small, very dense seismic array down at the migration path of a good-sized episodic tremor and slip (ETS) event. In detail, it was an 84-element, 1300-m-aperture temporary seismic array in northern Washington, and the migration path of the May 2008 ETS event was 30-40 km directly underneath. Our beamforming technique tracked the time, incident angle, and azimuth of tremor radiation in unprecedented detail. We located the tremor by assuming it occurs on the subduction interface, estimated relative tremor moment released by each detected tremor window, and mapped it on the interface [Ghosh et al., GRL, 2009]. Fortunately for our ability to image it, the tremor generally appears to emanate from small regions, and we were surprised by how steadily the regions migrated with time. For the first time in Cascadia, we found convergence-parallel transient streaks of tremor migrating at velocities of several tens of km/hr, with movement in both up- and down-dip directions. Similar patterns have been seen in Japan [Shelly, G3, 2007]. This is in contrast to the long-term along-strike marching of tremor at 10 km/day. These streaks tend to propagate steadily and often repeat the same track on the interface multiple times. They light up persistent moment patches on the interface by a combination of increased amplitude and longer residence time within the patches. The up- and down-dip migration dominates the 2 days of tremor most clearly imaged by our array. The tendency of the streaks to fill in bands is the subject of the presentation of Ghosh et al. here. The physical

  14. On-Orbit Camera Misalignment Estimation Framework and Its Application to Earth Observation Satellite

    Directory of Open Access Journals (Sweden)

    Seungwoo Lee

    2015-03-01

    Full Text Available Despite the efforts for precise alignment of imaging sensors and attitude sensors before launch, the accuracy of pre-launch alignment is limited. The misalignment between attitude frame and camera frame is especially important as it is related to the localization error of the spacecraft, which is one of the essential factors of satellite image quality. In this paper, a framework for camera misalignment estimation is presented with its application to a high-resolution earth-observation satellite—Deimos-2. The framework intends to provide a solution for estimation and correction of the camera misalignment of a spacecraft, covering image acquisition planning to mathematical solution of camera misalignment. Considerations for effective image acquisition planning to obtain reliable results are discussed, followed by a detailed description on a practical method for extracting many GCPs automatically using reference ortho-photos. Patterns of localization errors that commonly occur due to the camera misalignment are also investigated. A mathematical model for camera misalignment estimation is described comprehensively. The results of simulation experiments showing the validity and accuracy of the misalignment estimation model are provided. The proposed framework was applied to Deimos-2. The real-world data and results from Deimos-2 are presented.

  15. Observation of runaway electrons by infrared camera in J-TEXT

    Energy Technology Data Exchange (ETDEWEB)

    Tong, R. H.; Chen, Z. Y., E-mail: zychen@hust.edu.cn; Zhang, M.; Huang, D. W.; Yan, W.; Zhuang, G. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-11-15

    When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase. With a fast acquisition of the camera, the behavior of runaway electron beam has been observed directly during the runaway current plateau following the massive gas injection triggered disruptions.

  16. Streaked, x-ray-transmission-grating spectrometer

    International Nuclear Information System (INIS)

    Ceglio, N.M.; Roth, M.; Hawryluk, A.M.

    1981-08-01

    A free standing x-ray transmission grating has been coupled with a soft x-ray streak camera to produce a time resolved x-ray spectrometer. The instrument has a temporal resolution of approx. 20 psec, is capable of covering a broad spectral range, 2 to 120 A, has high sensitivity, and is simple to use requiring no complex alignment procedure. In recent laser fusion experiments the spectrometer successfully recorded time resolved spectra over the range 10 to 120 A with a spectral resolving power, lambda/Δlambda of 4 to 50, limited primarily by source size and collimation effects

  17. Weather and atmosphere observation with the ATOM all-sky camera

    Directory of Open Access Journals (Sweden)

    Jankowsky Felix

    2015-01-01

    Full Text Available The Automatic Telescope for Optical Monitoring (ATOM for H.E.S.S. is an 75 cm optical telescope which operates fully automated. As there is no observer present during observation, an auxiliary all-sky camera serves as weather monitoring system. This device takes an all-sky image of the whole sky every three minutes. The gathered data then undergoes live-analysis by performing astrometric comparison with a theoretical night sky model, interpreting the absence of stars as cloud coverage. The sky monitor also serves as tool for a meteorological analysis of the observation site of the the upcoming Cherenkov Telescope Array. This overview covers design and benefits of the all-sky camera and additionally gives an introduction into current efforts to integrate the device into the atmosphere analysis programme of H.E.S.S.

  18. Networked web-cameras monitor congruent seasonal development of birches with phenological field observations

    Science.gov (United States)

    Peltoniemi, Mikko; Aurela, Mika; Böttcher, Kristin; Kolari, Pasi; Loehr, John; Karhu, Jouni; Kubin, Eero; Linkosalmi, Maiju; Melih Tanis, Cemal; Nadir Arslan, Ali

    2017-04-01

    Ecosystems' potential to provide services, e.g. to sequester carbon is largely driven by the phenological cycle of vegetation. Timing of phenological events is required for understanding and predicting the influence of climate change on ecosystems and to support various analyses of ecosystem functioning. We established a network of cameras for automated monitoring of phenological activity of vegetation in boreal ecosystems of Finland. Cameras were mounted on 14 sites, each site having 1-3 cameras. In this study, we used cameras at 11 of these sites to investigate how well networked cameras detect phenological development of birches (Betula spp.) along the latitudinal gradient. Birches are interesting focal species for the analyses as they are common throughout Finland. In our cameras they often appear in smaller quantities within dominant species in the images. Here, we tested whether small scattered birch image elements allow reliable extraction of color indices and changes therein. We compared automatically derived phenological dates from these birch image elements to visually determined dates from the same image time series, and to independent observations recorded in the phenological monitoring network from the same region. Automatically extracted season start dates based on the change of green color fraction in the spring corresponded well with the visually interpreted start of season, and field observed budburst dates. During the declining season, red color fraction turned out to be superior over green color based indices in predicting leaf yellowing and fall. The latitudinal gradients derived using automated phenological date extraction corresponded well with gradients based on phenological field observations from the same region. We conclude that already small and scattered birch image elements allow reliable extraction of key phenological dates for birch species. Devising cameras for species specific analyses of phenological timing will be useful for

  19. Airborne hyperspectral observations of surface and cloud directional reflectivity using a commercial digital camera

    Directory of Open Access Journals (Sweden)

    A. Ehrlich

    2012-04-01

    Full Text Available Spectral radiance measurements by a digital single-lens reflex camera were used to derive the directional reflectivity of clouds and different surfaces in the Arctic. The camera has been calibrated radiometrically and spectrally to provide accurate radiance measurements with high angular resolution. A comparison with spectral radiance measurements with the Spectral Modular Airborne Radiation measurement sysTem (SMART-Albedometer showed an agreement within the uncertainties of both instruments (6% for both. The directional reflectivity in terms of the hemispherical directional reflectance factor (HDRF was obtained for sea ice, ice-free ocean and clouds. The sea ice, with an albedo of ρ = 0.96 (at 530 nm wavelength, showed an almost isotropic HDRF, while sun glint was observed for the ocean HDRF (ρ = 0.12. For the cloud observations with ρ = 0.62, the cloudbow – a backscatter feature typically for scattering by liquid water droplets – was covered by the camera. For measurements above heterogeneous stratocumulus clouds, the required number of images to obtain a mean HDRF that clearly exhibits the cloudbow has been estimated at about 50 images (10 min flight time. A representation of the HDRF as a function of the scattering angle only reduces the image number to about 10 (2 min flight time.

    The measured cloud and ocean HDRF have been compared to radiative transfer simulations. The ocean HDRF simulated with the observed surface wind speed of 9 m s−1 agreed best with the measurements. For the cloud HDRF, the best agreement was obtained by a broad and weak cloudbow simulated with a cloud droplet effective radius of Reff = 4 μm. This value agrees with the particle sizes derived from in situ measurements and retrieved from the spectral radiance of the SMART-Albedometer.

  20. Initial inflight calibration for Hayabusa2 optical navigation camera (ONC) for science observations of asteroid Ryugu

    Science.gov (United States)

    Suzuki, H.; Yamada, M.; Kouyama, T.; Tatsumi, E.; Kameda, S.; Honda, R.; Sawada, H.; Ogawa, N.; Morota, T.; Honda, C.; Sakatani, N.; Hayakawa, M.; Yokota, Y.; Yamamoto, Y.; Sugita, S.

    2018-01-01

    Hayabusa2, the first sample return mission to a C-type asteroid was launched by the Japan Aerospace Exploration Agency (JAXA) on December 3, 2014 and will arrive at the asteroid in the middle of 2018 to collect samples from its surface, which may contain both hydrated minerals and organics. The optical navigation camera (ONC) system on board the Hayabusa2 consists of three individual framing CCD cameras, ONC-T for a telescopic nadir view, ONC-W1 for a wide-angle nadir view, and ONC-W2 for a wide-angle slant view will be used to observe the surface of Ryugu. The cameras will be used to measure the global asteroid shape, local morphologies, and visible spectroscopic properties. Thus, image data obtained by ONC will provide essential information to select landing (sampling) sites on the asteroid. This study reports the results of initial inflight calibration based on observations of Earth, Mars, Moon, and stars to verify and characterize the optical performance of the ONC, such as flat-field sensitivity, spectral sensitivity, point-spread function (PSF), distortion, and stray light of ONC-T, and distortion for ONC-W1 and W2. We found some potential problems that may influence our science observations. This includes changes in sensitivity of flat fields for all bands from those that were measured in the pre-flight calibration and existence of a stray light that arises under certain conditions of spacecraft attitude with respect to the sun. The countermeasures for these problems were evaluated by using data obtained during initial in-flight calibration. The results of our inflight calibration indicate that the error of spectroscopic measurements around 0.7 μm using 0.55, 0.70, and 0.86 μm bands of the ONC-T can be lower than 0.7% after these countermeasures and pixel binning. This result suggests that our ONC-T would be able to detect typical strength (∼3%) of the serpentine absorption band often found on CM chondrites and low albedo asteroids with ≥ 4

  1. Streak detection and analysis pipeline for optical images

    Science.gov (United States)

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

    2014-07-01

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

  2. DuOCam: A Two-Channel Camera for Simultaneous Photometric Observations of Stellar Clusters

    Science.gov (United States)

    Maier, Erin R.; Witt, Emily; Depoy, Darren L.; Schmidt, Luke M.

    2017-01-01

    We have designed the Dual Observation Camera (DuOCam), which uses commercial, off-the-shelf optics to perform simultaneous photometric observations of astronomical objects at red and blue wavelengths. Collected light enters DuOCam’s optical assembly, where it is collimated by a negative doublet lens. It is then separated by a 45 degree blue dichroic filter (transmission bandpass: 530 - 800 nm, reflection bandpass: 400 - 475 nm). Finally, the separated light is focused by two identical positive doublet lenses onto two independent charge-coupled devices (CCDs), the SBIG ST-8300M and the SBIG STF-8300M. This optical assembly converts the observing telescope to an f/11 system, which balances maximum field of view with optimum focus. DuOCam was commissioned on the McDonald Observatory 0.9m, f/13.5 telescope from July 21st - 24th, 2016. Observations of three globular and three open stellar clusters were carried out. The resulting data were used to construct R vs. B-R color magnitude diagrams for a selection of the observed clusters. The diagrams display the characteristic evolutionary track for a stellar cluster, including the main sequence and main sequence turn-off.

  3. A telescopic cinema sound camera for observing high altitude aerospace vehicles

    Science.gov (United States)

    Slater, Dan

    2014-09-01

    Rockets and other high altitude aerospace vehicles produce interesting visual and aural phenomena that can be remotely observed from long distances. This paper describes a compact, passive and covert remote sensing system that can produce high resolution sound movies at >100 km viewing distances. The telescopic high resolution camera is capable of resolving and quantifying space launch vehicle dynamics including plume formation, staging events and payload fairing jettison. Flight vehicles produce sounds and vibrations that modulate the local electromagnetic environment. These audio frequency modulations can be remotely sensed by passive optical and radio wave detectors. Acousto-optic sensing methods were primarily used but an experimental radioacoustic sensor using passive micro-Doppler radar techniques was also tested. The synchronized combination of high resolution flight vehicle imagery with the associated vehicle sounds produces a cinema like experience that that is useful in both an aerospace engineering and a Hollywood film production context. Examples of visual, aural and radar observations of the first SpaceX Falcon 9 v1.1 rocket launch are shown and discussed.

  4. SPECKLE CAMERA OBSERVATIONS FOR THE NASA KEPLER MISSION FOLLOW-UP PROGRAM

    International Nuclear Information System (INIS)

    Howell, Steve B.; Everett, Mark E.; Sherry, William; Horch, Elliott; Ciardi, David R.

    2011-01-01

    We present the first results from a speckle imaging survey of stars classified as candidate exoplanet host stars discovered by the Kepler mission. We use speckle imaging to search for faint companions or closely aligned background stars that could contribute flux to the Kepler light curves of their brighter neighbors. Background stars are expected to contribute significantly to the pool of false positive candidate transiting exoplanets discovered by the Kepler mission, especially in the case that the faint neighbors are eclipsing binary stars. Here, we describe our Kepler follow-up observing program, the speckle imaging camera used, our data reduction, and astrometric and photometric performance. Kepler stars range from R = 8 to 16 and our observations attempt to provide background non-detection limits 5-6 mag fainter and binary separations of ∼0.05-2.0 arcsec. We present data describing the relative brightness, separation, and position angles for secondary sources, as well as relative plate limits for non-detection of faint nearby stars around each of 156 target stars. Faint neighbors were found near 10 of the stars.

  5. Observations of temporal change of nighttime cloud cover from Himawari 8 and ground-based sky camera over Chiba, Japan

    Science.gov (United States)

    Lagrosas, N.; Gacal, G. F. B.; Kuze, H.

    2017-12-01

    Detection of nighttime cloud from Himawari 8 is implemented using the difference of digital numbers from bands 13 (10.4µm) and 7 (3.9µm). The digital number difference of -1.39x104 can be used as a threshold to separate clouds from clear sky conditions. To look at observations from the ground over Chiba, a digital camera (Canon Powershot A2300) is used to take images of the sky every 5 minutes at an exposure time of 5s at the Center for Environmental Remote Sensing, Chiba University. From these images, cloud cover values are obtained using threshold algorithm (Gacal, et al, 2016). Ten minute nighttime cloud cover values from these two datasets are compared and analyzed from 29 May to 05 June 2017 (20:00-03:00 JST). When compared with lidar data, the camera can detect thick high level clouds up to 10km. The results show that during clear sky conditions (02-03 June), both camera and satellite cloud cover values show 0% cloud cover. During cloudy conditions (05-06 June), the camera shows almost 100% cloud cover while satellite cloud cover values range from 60 to 100%. These low values can be attributed to the presence of low-level thin clouds ( 2km above the ground) as observed from National Institute for Environmental Studies lidar located inside Chiba University. This difference of cloud cover values shows that the camera can produce accurate cloud cover values of low level clouds that are sometimes not detected by satellites. The opposite occurs when high level clouds are present (01-02 June). Derived satellite cloud cover shows almost 100% during the whole night while ground-based camera shows cloud cover values that range from 10 to 100% during the same time interval. The fluctuating values can be attributed to the presence of thin clouds located at around 6km from the ground and the presence of low level clouds ( 1km). Since the camera relies on the reflected city lights, it is possible that the high level thin clouds are not observed by the camera but is

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

    Science.gov (United States)

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

    2016-09-01

    One of urgent security problems is a detection of objects placed inside the human body. Obviously, for safety reasons one cannot use X-rays for such object detection widely and often. Three years ago, we have demonstrated principal possibility to see a temperature trace, induced by food eating or water drinking, on the human body skin by using a passive THz camera. However, this camera is very expensive. Therefore, for practice it will be very convenient if one can use the IR camera for this purpose. In contrast to passive THz camera using, the IR camera does not allow to see the object under clothing, if an image, produced by this camera, is used directly. Of course, this is a big disadvantage for a security problem solution based on the IR camera using. To overcome this disadvantage we develop novel approach for computer processing of IR camera images. It allows us to increase a temperature resolution of IR camera as well as increasing of human year effective susceptibility. As a consequence of this, a possibility for seeing of a human body temperature changing through clothing appears. We analyze IR images of a person, which drinks water and eats chocolate. We follow a temperature trace on human body skin, caused by changing of temperature inside the human body. Some experiments were made with measurements of a body temperature covered by T-shirt. Shown results are very important for the detection of forbidden objects, cancelled inside the human body, by using non-destructive control without using X-rays.

  7. An evaluation of the effectiveness of observation camera placement within the MeerKAT radio telescope project

    Directory of Open Access Journals (Sweden)

    Heyns, Andries

    2015-08-01

    Full Text Available A recent development within the MeerKAT sub-project of the Square Kilometre Array radio telescope network was the placement of a network of three observation cameras in pursuit of two specific visibility objectives. In this paper, we evaluate the effectiveness of the locations of the MeerKAT observation camera network according to a novel multi-objective geographic information systems-based facility location framework. We find that the configuration chosen and implemented by the MeerKAT decision-makers is of very high quality, although we are able to uncover slightly superior alternative placement configurations. A significant amount of time and effort could, however, have been saved in the process of choosing the appropriate camera sites, had our solutions been available to the decision-makers.

  8. Thermal Analysis of MIRIS Space Observation Camera for Verification of Passive Cooling

    Directory of Open Access Journals (Sweden)

    Duk-Hang Lee

    2012-09-01

    Full Text Available We conducted thermal analyses and cooling tests of the space observation camera (SOC of the multi-purpose infrared imaging system (MIRIS to verify passive cooling. The thermal analyses were conducted with NX 7.0 TMG for two cases of attitude of the MIRIS: for the worst hot case and normal case. Through the thermal analyses of the flight model, it was found that even in the worst case the telescope could be cooled to less than 206°K. This is similar to the results of the passive cooling test (~200.2°K. For the normal attitude case of the analysis, on the other hand, the SOC telescope was cooled to about 160°K in 10 days. Based on the results of these analyses and the test, it was determined that the telescope of the MIRIS SOC could be successfully cooled to below 200°K with passive cooling. The SOC is, therefore, expected to have optimal performance under cooled conditions in orbit.

  9. Absolute calibration method for fast-streaked, fiber optic light collection, spectroscopy systems

    International Nuclear Information System (INIS)

    Johnston, Mark D.; Frogget, Brent; Oliver, Bryan Velten; Maron, Yitzhak; Droemer, Darryl W.; Crain, Marlon D.

    2010-01-01

    This report outlines a convenient method to calibrate fast (<1ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such a system is used to collect spectral data on plasmas generated in the A-K gap of electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA). On RITS, light is collected through a small diameter (200 micron) optical fiber and recorded on a fast streak camera at the output of 1 meter Czerny-Turner monochromator (F/7 optics). To calibrate such a system, it is necessary to efficiently couple light from a spectral lamp into a 200 micron diameter fiber, split it into its spectral components, with 10 Angstroms or less resolution, and record it on a streak camera with 1ns or less temporal resolution.

  10. 2D turbulence structure observed by a fast framing camera system in linear magnetized device PANTA

    International Nuclear Information System (INIS)

    Ohdachi, Satoshi; Inagaki, S.; Kobayashi, T.; Goto, M.

    2015-01-01

    Mesoscale structure, such as the zonal flow and the streamer plays important role in the drift-wave turbulence. The interaction of the mesoscale structure and the turbulence is not only interesting phenomena but also a key to understand the turbulence driven transport in the magnetically confined plasmas. In the cylindrical magnetized device, PANTA, the interaction of the streamer and the drift wave has been found by the bi-spectrum analysis of the turbulence. In order to study the mesoscale physics directly, the 2D turbulence is studied by a fast-framing visible camera system view from a window located at the end plate of the device. The parameters of the plasma is the following; Te∼3eV, n ∼ 1x10 19 m -3 , Ti∼0.3eV, B=900G, Neutral pressure P n =0.8 mTorr, a∼ 6cm, L=4m, Helicon source (7MHz, 3kW). Fluctuating component of the visible image is decomposed by the Fourier-Bessel expansion method. Several rotating mode is observed simultaneously. From the images, m = 1 (f∼0.7 kHz) and m = 2, 3 (f∼-3.4 kHz) components which rotate in the opposite direction can be easily distinguished. Though the modes rotate constantly in most time, there appear periods where the radially complicated node structure is formed (for example, m=3 component, t = 142.5∼6 in the figure) and coherent mode structures are disturbed. Then, a new rotating period is started again with different phase of the initial rotation until the next event happens. The typical time interval of the event is 0.5 to 1.0 times of the one rotation of the slow m = 1 mode. The wave-wave interaction might be interrupted occasionally. Detailed analysis of the turbulence using imaging technique will be discussed. (author)

  11. Development and setting of a time-lapse video camera system for the Antarctic lake observation

    Directory of Open Access Journals (Sweden)

    Sakae Kudoh

    2010-11-01

    Full Text Available A submersible video camera system, which aimed to record the growth image of aquatic vegetation in Antarctic lakes for one year, was manufactured. The system consisted of a video camera, a programmable controller unit, a lens-cleaning wiper with a submersible motor, LED lights, and a lithium ion battery unit. Changes of video camera (High Vision System and modification of the lens-cleaning wiper allowed higher sensitivity and clearer recording images compared to the previous submersible video without increasing the power consumption. This system was set on the lake floor in Lake Naga Ike (a tentative name in Skarvsnes in Soya Coast, during the summer activity of the 51th Japanese Antarctic Research Expedition. Interval record of underwater visual image for one year have been started by our diving operation.

  12. Betting Decision Under Break-Streak Pattern: Evidence from Casino Gaming.

    Science.gov (United States)

    Fong, Lawrence Hoc Nang; So, Amy Siu Ian; Law, Rob

    2016-03-01

    Cognitive bias is prevalent among gamblers, especially those with gambling problems. Grounded in the heuristics theories, this study contributes to the literature by examining a cognitive bias triggered by the break streak pattern in the casino setting. We postulate that gamblers tend to bet on the latest outcome when there is a break-streak pattern. Moreover, three determinants of the betting decision under break-streak pattern, including the streak length of the alternative outcome, the frequency of the latest outcome, and gender, were identified and examined in this study. A non-participatory observational study was conducted among the Cussec gamblers in a casino in Macao. An analysis of 1229 bets confirms our postulation, particularly when the streak of the alternative outcome is long, the latest outcome is frequent, and the gamblers are females. The findings provide meaningful implications for casino management and public policymakers regarding the minimization of gambling harm.

  13. Diving-related visual loss in the setting of angioid streaks: report of two cases.

    Science.gov (United States)

    Angulo Bocco, Maria I; Spielberg, Leigh; Coppens, Greet; Catherine, Janet; Verougstraete, Claire; Leys, Anita M

    2012-01-01

    The purpose of this study was to report diving-related visual loss in the setting of angioid streaks. Observational case reports of two patients with angioid streaks suffering sudden visual loss immediately after diving. Two young adult male patients presented with visual loss after diving headfirst. Funduscopy revealed angioid streaks, peau d'orange, subretinal hemorrhages, and ruptures of Bruch membrane. Choroidal neovascularization developed during follow-up. Both patients had an otherwise uneventful personal and familial medical history. In patients with angioid streaks, diving headfirst can lead to subretinal hemorrhages and traumatic ruptures in Bruch membrane and increase the risk of maculopathy. Ophthalmologists should caution patients with angioid streaks against diving headfirst.

  14. An ebCMOS camera system for marine bioluminescence observation: The LuSEApher prototype

    Energy Technology Data Exchange (ETDEWEB)

    Dominjon, A., E-mail: a.dominjon@ipnl.in2p3.fr [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Ageron, M. [CNRS/IN2P3, Centre de Physique des Particules de Marseille, Marseille, F-13288 (France); Barbier, R. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Universite de Lyon, Universite Lyon 1, Lyon F-69003 (France); Billault, M.; Brunner, J. [CNRS/IN2P3, Centre de Physique des Particules de Marseille, Marseille, F-13288 (France); Cajgfinger, T. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Universite de Lyon, Universite Lyon 1, Lyon F-69003 (France); Calabria, P. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Chabanat, E. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France); Universite de Lyon, Universite Lyon 1, Lyon F-69003 (France); Chaize, D.; Doan, Q.T.; Guerin, C.; Houles, J.; Vagneron, L. [CNRS/IN2P3, Institut de Physique Nucleaire de Lyon, Villeurbanne F-69622 (France)

    2012-12-11

    The ebCMOS camera, called LuSEApher, is a marine bioluminescence recorder device adapted to extreme low light level. This prototype is based on the skeleton of the LUSIPHER camera system originally developed for fluorescence imaging. It has been installed at 2500 m depth off the Mediterranean shore on the site of the ANTARES neutrino telescope. The LuSEApher camera is mounted on the Instrumented Interface Module connected to the ANTARES network for environmental science purposes (European Seas Observatory Network). The LuSEApher is a self-triggered photo detection system with photon counting ability. The presentation of the device is given and its performances such as the single photon reconstruction, noise performances and trigger strategy are presented. The first recorded movies of bioluminescence are analyzed. To our knowledge, those types of events have never been obtained with such a sensitivity and such a frame rate. We believe that this camera concept could open a new window on bioluminescence studies in the deep sea.

  15. Hubble Space Telescope Wide Field Planetary Camera 2 Observations of Neptune

    Science.gov (United States)

    1995-01-01

    Two groups have recently used the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC 2) to acquire new high-resolution images of the planet Neptune. Members of the WFPC-2 Science Team, lead by John Trauger, acquired the first series of images on 27 through 29 June 1994. These were the highest resolution images of Neptune taken since the Voyager-2 flyby in August of 1989. A more comprehensive program is currently being conducted by Heidi Hammel and Wes Lockwood. These two sets of observations are providing a wealth of new information about the structure, composition, and meteorology of this distant planet's atmosphere.Neptune is currently the most distant planet from the sun, with an orbital radius of 4.5 billion kilometers (2.8 billion miles, or 30 Astronomical Units). Even though its diameter is about four times that of the Earth (49,420 vs. 12,742 km), ground-based telescopes reveal a tiny blue disk that subtends less than 1/1200 of a degree (2.3 arc-seconds). Neptune has therefore been a particularly challenging object to study from the ground because its disk is badly blurred by the Earth's atmosphere. In spite of this, ground-based astronomers had learned a great deal about this planet since its position was first predicted by John C. Adams and Urbain Leverrier in 1845. For example, they had determined that Neptune was composed primarily of hydrogen and helium gas, and that its blue color caused by the presence of trace amounts of the gas methane, which absorbs red light. They had also detected bright cloud features whose brightness changed with time, and tracked these clouds to infer a rotation period between 17 and 22 hours.When the Voyager-2 spacecraft flew past the Neptune in 1989, its instruments revealed a surprising array of meteorological phenomena, including strong winds, bright, high-altitude clouds, and two large dark spots attributed to long-lived giant storm systems. These bright clouds and dark spots were tracked as they moved

  16. Nonlinear streak computation using boundary region equations

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-08-01

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

  17. A method of camera calibration in the measurement process with reference mark for approaching observation space target

    Science.gov (United States)

    Zhang, Hua; Zeng, Luan

    2017-11-01

    Binocular stereoscopic vision can be used for space-based space targets near observation. In order to solve the problem that the traditional binocular vision system cannot work normally after interference, an online calibration method of binocular stereo measuring camera with self-reference is proposed. The method uses an auxiliary optical imaging device to insert the image of the standard reference object into the edge of the main optical path and image with the target on the same focal plane, which is equivalent to a standard reference in the binocular imaging optical system; When the position of the system and the imaging device parameters are disturbed, the image of the standard reference will change accordingly in the imaging plane, and the position of the standard reference object does not change. The camera's external parameters can be re-calibrated by the visual relationship of the standard reference object. The experimental results show that the maximum mean square error of the same object can be reduced from the original 72.88mm to 1.65mm when the right camera is deflected by 0.4 degrees and the left camera is high and low with 0.2° rotation. This method can realize the online calibration of binocular stereoscopic vision measurement system, which can effectively improve the anti - jamming ability of the system.

  18. Nighttime Near Infrared Observations of Augustine Volcano Jan-Apr, 2006 Recorded With a Small Astronomical CCD Camera

    Science.gov (United States)

    Sentman, D.; McNutt, S.; Reyes, C.; Stenbaek-Nielsen, H.; Deroin, N.

    2006-12-01

    Nighttime observations of Augustine Volcano were made during Jan-Apr, 2006 using a small, unfiltered, astronomical CCD camera operating from Homer, Alaska. Time-lapse images of the volcano were made looking across the open water of the Cook Inlet over a slant range of ~105 km. A variety of volcano activities were observed that originated in near-infrared (NIR) 0.9-1.1 micron emissions, which were detectable at the upper limit of the camera passband but were otherwise invisible to the naked eye. These activities included various types of steam releases, pyroclastic flows, rockfalls and debris flows that were correlated very closely with seismic measurements made from instruments located within 4 km on the volcanic island. Specifically, flow events to the east (towards the camera) produced high amplitudes on the eastern seismic stations and events presumably to the west were stronger on western stations. The ability to detect nighttime volcanic emissions in the NIR over large horizontal distances using standard silicon CCD technology, even in the presence of weak intervening fog, came as a surprise, and is due to a confluence of several mutually reinforcing factors: (1) Hot enough (~1000K) thermal emissions from the volcano that the short wavelength portion of the Planck radiation curve overlaps the upper portions (0.9-1.1 micron) of the sensitivity of the silicon CCD detectors, and could thus be detected, (2) The existence of several atmospheric transmission windows within the NIR passband of the camera for the emissions to propagate with relatively small attenuation through more than 10 atmospheres, and (3) in the case of fog, forward Mie scattering.

  19. Slope streaks on Mars: A new “wet” mechanism

    Science.gov (United States)

    Kreslavsky, Mikhail A.; Head, James W.

    2009-06-01

    Slope steaks are one of the most intriguing modern phenomena observed on Mars. They have been mostly interpreted as some specific type of granular flow. We propose another mechanism for slope streak formation on Mars. It involves natural seasonal formation of a modest amount of highly concentrated chloride brines within a seasonal thermal skin, and runaway propagation of percolation fronts. Given the current state of knowledge of temperature regimes and the composition and structure of the surface layer in the slope streak regions, this mechanism is consistent with the observational constraints; it requires an assumption that a significant part of the observed chlorine to be in form of calcium and ferric chloride, and a small part of the observed hydrogen to be in form of water ice. This "wet" mechanism has a number of appealing advantages in comparison to the widely accepted "dry" granular flow mechanism. Potential tests for the "wet" mechanism include better modeling of the temperature regime and observations of the seasonality of streak formation.

  20. Streak detection and analysis pipeline for space-debris optical images

    Science.gov (United States)

    Virtanen, Jenni; Poikonen, Jonne; Säntti, Tero; Komulainen, Tuomo; Torppa, Johanna; Granvik, Mikael; Muinonen, Karri; Pentikäinen, Hanna; Martikainen, Julia; Näränen, Jyri; Lehti, Jussi; Flohrer, Tim

    2016-04-01

    We describe a novel data-processing and analysis pipeline for optical observations of moving objects, either of natural (asteroids, meteors) or artificial origin (satellites, space debris). The monitoring of the space object populations requires reliable acquisition of observational data, to support the development and validation of population models and to build and maintain catalogues of orbital elements. The orbital catalogues are, in turn, needed for the assessment of close approaches (for asteroids, with the Earth; for satellites, with each other) and for the support of contingency situations or launches. For both types of populations, there is also increasing interest to detect fainter objects corresponding to the small end of the size distribution. The ESA-funded StreakDet (streak detection and astrometric reduction) activity has aimed at formulating and discussing suitable approaches for the detection and astrometric reduction of object trails, or streaks, in optical observations. Our two main focuses are objects in lower altitudes and space-based observations (i.e., high angular velocities), resulting in long (potentially curved) and faint streaks in the optical images. In particular, we concentrate on single-image (as compared to consecutive frames of the same field) and low-SNR detection of objects. Particular attention has been paid to the process of extraction of all necessary information from one image (segmentation), and subsequently, to efficient reduction of the extracted data (classification). We have developed an automated streak detection and processing pipeline and demonstrated its performance with an extensive database of semisynthetic images simulating streak observations both from ground-based and space-based observing platforms. The average processing time per image is about 13 s for a typical 2k-by-2k image. For long streaks (length >100 pixels), primary targets of the pipeline, the detection sensitivity (true positives) is about 90% for

  1. System Configuration and Operation Plan of Hayabusa2 DCAM3-D Camera System for Scientific Observation During SCI Impact Experiment

    Science.gov (United States)

    Ogawa, Kazunori; Shirai, Kei; Sawada, Hirotaka; Arakawa, Masahiko; Honda, Rie; Wada, Koji; Ishibashi, Ko; Iijima, Yu-ichi; Sakatani, Naoya; Nakazawa, Satoru; Hayakawa, Hajime

    2017-07-01

    An artificial impact experiment is scheduled for 2018-2019 in which an impactor will collide with asteroid 162137 Ryugu (1999 JU3) during the asteroid rendezvous phase of the Hayabusa2 spacecraft. The small carry-on impactor (SCI) will shoot a 2-kg projectile at 2 km/s to create a crater 1-10 m in diameter with an expected subsequent ejecta curtain of a 100-m scale on an ideal sandy surface. A miniaturized deployable camera (DCAM3) unit will separate from the spacecraft at about 1 km from impact, and simultaneously conduct optical observations of the experiment. We designed and developed a camera system (DCAM3-D) in the DCAM3, specialized for scientific observations of impact phenomenon, in order to clarify the subsurface structure, construct theories of impact applicable in a microgravity environment, and identify the impact point on the asteroid. The DCAM3-D system consists of a miniaturized camera with a wide-angle and high-focusing performance, high-speed radio communication devices, and control units with large data storage on both the DCAM3 unit and the spacecraft. These components were successfully developed under severe constraints of size, mass and power, and the whole DCAM3-D system has passed all tests verifying functions, performance, and environmental tolerance. Results indicated sufficient potential to conduct the scientific observations during the SCI impact experiment. An operation plan was carefully considered along with the configuration and a time schedule of the impact experiment, and pre-programed into the control unit before the launch. In this paper, we describe details of the system design concept, specifications, and the operating plan of the DCAM3-D system, focusing on the feasibility of scientific observations.

  2. Electron streaking in the autoionization region of H2

    International Nuclear Information System (INIS)

    Palacios, Alicia; González-Castrillo, Alberto; Martín, Fernando

    2015-01-01

    We use a UV-pump/IR-probe scheme, combining a single attosecond UV pulse and a 750 nm IR pulse, to explore laser-assisted photoionization of the hydrogen molecule in the autoionization region. The electron energy distributions exhibit unusual streaking patterns that are explored for different angles of the electron ejection with respect to the polarization vector and the molecular axis. Moreover, by controlling the time delay between the pulses, we observe that one can suppress the autoionization channel. (paper)

  3. Study and use of an infrared camera optimized for ground based observations in the 10 micron wavelength range

    International Nuclear Information System (INIS)

    Remy, Sophie

    1991-01-01

    Astronomical observations in the 10 micron atmospheric window provide very important information for many of astrophysical topics. But because of the very large terrestrial photon background at that wavelength, ground based observations have been impeded. On the other band, the ground based telescopes offer a greater angular resolution than the spatially based telescopes. The recent development of detector arrays for the mid infrared range made easier the development of infrared cameras with optimized detectors for astronomical observations from the ground. The CAMIRAS infrared camera, built by the 'Service d'Astrophysique' in Saclay is the instrument we have studied and we present its performances. Its sensitivity, given for an integration time of one minute on source and a signal to noise ratio of 3, is 0.15 Jy for punctual sources, and 20 mJy arcs"-"2 for extended sources. But we need to get rid of the enormous photon background so we have to find a better way of observation based on modulation techniques as 'chopping' or 'nodding'. Thus we show that a modulation about 1 Hz is satisfactory with our detectors arrays without perturbing the signal to noise ratio. As we have a good instrument and because we are able to get rid of the photon background, we can study astronomical objects. Results from a comet, dusty stellar disks, and an ultra-luminous galaxy are presented. (author) [fr

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

  5. Observation of interaction of shock wave with gas bubble by image converter camera

    Science.gov (United States)

    Yoshii, M.; Tada, M.; Tsuji, T.; Isuzugawa, Kohji

    1995-05-01

    When a spark discharge occurs at the first focal point of a semiellipsoid or a reflector located in water, a spherical shock wave is produced. A part of the wave spreads without reflecting on the reflector and is called direct wave in this paper. Another part reflects on the semiellipsoid and converges near the second focal point, that is named the focusing wave, and locally produces a high pressure. This phenomenon is applied to disintegrators of kidney stone. But it is concerned that cavitation bubbles induced in the body by the expansion wave following the focusing wave will injure human tissue around kidney stone. In this paper, in order to examine what happens when shock waves strike bubbles on human tissue, the aspect that an air bubble is truck by the spherical shock wave or its behavior is visualized by the schlieren system and its photographs are taken using an image converter camera. Besides,the variation of the pressure amplitude caused by the shock wave and the flow of water around the bubble is measured with a pressure probe.

  6. A fast framing camera system for observation of acceleration and ablation of cryogenic hydrogen pellet in ASDEX Upgrade plasmas

    International Nuclear Information System (INIS)

    Kocsis, G.; Kalvin, S.; Veres, G.; Cierpka, P.; Lang, P.T.; Neuhauser, J.; Wittman, C.; ASDEX Upgrade Team

    2004-01-01

    An observation system using fast digital cameras was developed to measure a cryogenic hydrogen pellet's cloud structure, trajectory, and velocity changes during its ablation in ASDEX Upgrade plasmas. In this article the system, the applied numerical methods, and the results are presented. The three-dimensional pellet trajectory and velocity components were reconstructed from images of observations from two different directions. Pellet acceleration both in the radial and toroidal directions was detected. The pellet cloud distribution was measured with high spatio-temporal resolution. The cloud surrounding the pellet was found to be elongated along the magnetic field lines. Its typical size is 5-7 cm along the field lines and 2 cm in the perpendicular directions. A cloud extension in the poloidal direction was also observed which may be related to the drift of the detached part of the cloud

  7. Automated computer analysis of plasma-streak traces from SCYLLAC

    International Nuclear Information System (INIS)

    Whitman, R.L.; Jahoda, F.C.; Kruger, R.P.

    1977-01-01

    An automated computer analysis technique that locates and references the approximate centroid of single- or dual-streak traces from the Los Alamos Scientific Laboratory SCYLLAC facility is described. The technique also determines the plasma-trace width over a limited self-adjusting region. The plasma traces are recorded with streak cameras on Polaroid film, then scanned and digitized for processing. The analysis technique uses scene segmentation to separate the plasma trace from a reference fiducial trace. The technique employs two methods of peak detection; one for the plasma trace and one for the fiducial trace. The width is obtained using an edge-detection, or slope, method. Timing data are derived from the intensity modulation of the fiducial trace. To smooth (despike) the output graphs showing the plasma-trace centroid and width, a technique of ''twicing'' developed by Tukey was employed. In addition, an interactive sorting algorithm allows retrieval of the centroid, width, and fiducial data from any test shot plasma for post analysis. As yet, only a limited set of sixteen plasma traces has been processed using this technique

  8. Automated computer analysis of plasma-streak traces from SCYLLAC

    International Nuclear Information System (INIS)

    Whiteman, R.L.; Jahoda, F.C.; Kruger, R.P.

    1977-11-01

    An automated computer analysis technique that locates and references the approximate centroid of single- or dual-streak traces from the Los Alamos Scientific Laboratory SCYLLAC facility is described. The technique also determines the plasma-trace width over a limited self-adjusting region. The plasma traces are recorded with streak cameras on Polaroid film, then scanned and digitized for processing. The analysis technique uses scene segmentation to separate the plasma trace from a reference fiducial trace. The technique employs two methods of peak detection; one for the plasma trace and one for the fiducial trace. The width is obtained using an edge-detection, or slope, method. Timing data are derived from the intensity modulation of the fiducial trace. To smooth (despike) the output graphs showing the plasma-trace centroid and width, a technique of ''twicing'' developed by Tukey was employed. In addition, an interactive sorting algorithm allows retrieval of the centroid, width, and fiducial data from any test shot plasma for post analysis. As yet, only a limited set of the plasma traces has been processed with this technique

  9. Spectral analysis of amazon canopy phenology during the dry season using a tower hyperspectral camera and modis observations

    Science.gov (United States)

    de Moura, Yhasmin Mendes; Galvão, Lênio Soares; Hilker, Thomas; Wu, Jin; Saleska, Scott; do Amaral, Cibele Hummel; Nelson, Bruce Walker; Lopes, Aline Pontes; Wiedeman, Kenia K.; Prohaska, Neill; de Oliveira, Raimundo Cosme; Machado, Carolyne Bueno; Aragão, Luiz E. O. C.

    2017-09-01

    The association between spectral reflectance and canopy processes remains challenging for quantifying large-scale canopy phenological cycles in tropical forests. In this study, we used a tower-mounted hyperspectral camera in an eastern Amazon forest to assess how canopy spectral signals of three species are linked with phenological processes in the 2012 dry season. We explored different approaches to disentangle the spectral components of canopy phenology processes and analyze their variations over time using 17 images acquired by the camera. The methods included linear spectral mixture analysis (SMA); principal component analysis (PCA); continuum removal (CR); and first-order derivative analysis. In addition, three vegetation indices potentially sensitive to leaf flushing, leaf loss and leaf area index (LAI) were calculated: the Enhanced Vegetation Index (EVI), Normalized Difference Vegetation Index (NDVI) and the entitled Green-Red Normalized Difference (GRND) index. We inspected also the consistency of the camera observations using Moderate Resolution Imaging Spectroradiometer (MODIS) and available phenological data on new leaf production and LAI of young, mature and old leaves simulated by a leaf demography-ontogeny model. The results showed a diversity of phenological responses during the 2012 dry season with related changes in canopy structure and greenness values. Because of the differences in timing and intensity of leaf flushing and leaf shedding, Erisma uncinatum, Manilkara huberi and Chamaecrista xinguensis presented different green vegetation (GV) and non-photosynthetic vegetation (NPV) SMA fractions; distinct PCA scores; changes in depth, width and area of the 681-nm chlorophyll absorption band; and variations over time in the EVI, GRND and NDVI. At the end of dry season, GV increased for Erisma uncinatum, while NPV increased for Chamaecrista xinguensis. For Manilkara huberi, the NPV first increased in the beginning of August and then decreased toward

  10. Determination of frequencies of oscillations of cloud cavitation on a 2-D hydrofoil from high-speed camera observations

    Czech Academy of Sciences Publication Activity Database

    Zima, Patrik; Fürst, T.; Sedlář, M.; Komárek, M.; Huzlík, R.

    2016-01-01

    Roč. 28, č. 3 (2016), s. 369-378 ISSN 1001-6058 R&D Projects: GA ČR GA13-23550S Institutional support: RVO:61388998 Keywords : unsteady cavitation * oscillation frequency * high-speed camera observation Subject RIV: BK - Fluid Dynamics Impact factor: 1.174, year: 2016 http://ac.els-cdn.com/S1001605816606406/1-s2.0-S1001605816606406-main.pdf?_tid=dee3b8f4-4a62-11e6-9d83-00000aacb361&acdnat=1468570098_ce8b727c766e0f96ee20d505e7058102

  11. Social interactions of juvenile brown boobies at sea as observed with animal-borne video cameras.

    Directory of Open Access Journals (Sweden)

    Ken Yoda

    Full Text Available While social interactions play a crucial role on the development of young individuals, those of highly mobile juvenile birds in inaccessible environments are difficult to observe. In this study, we deployed miniaturised video recorders on juvenile brown boobies Sula leucogaster, which had been hand-fed beginning a few days after hatching, to examine how social interactions between tagged juveniles and other birds affected their flight and foraging behaviour. Juveniles flew longer with congeners, especially with adult birds, than solitarily. In addition, approximately 40% of foraging occurred close to aggregations of congeners and other species. Young seabirds voluntarily followed other birds, which may directly enhance their foraging success and improve foraging and flying skills during their developmental stage, or both.

  12. Near-Infrared Photon-Counting Camera for High-Sensitivity Observations

    Science.gov (United States)

    Jurkovic, Michael

    2012-01-01

    The dark current of a transferred-electron photocathode with an InGaAs absorber, responsive over the 0.9-to-1.7- micron range, must be reduced to an ultralow level suitable for low signal spectral astrophysical measurements by lowering the temperature of the sensor incorporating the cathode. However, photocathode quantum efficiency (QE) is known to reduce to zero at such low temperatures. Moreover, it has not been demonstrated that the target dark current can be reached at any temperature using existing photocathodes. Changes in the transferred-electron photocathode epistructure (with an In- GaAs absorber lattice-matched to InP and exhibiting responsivity over the 0.9- to-1.7- m range) and fabrication processes were developed and implemented that resulted in a demonstrated >13x reduction in dark current at -40 C while retaining >95% of the approximately equal to 25% saturated room-temperature QE. Further testing at lower temperature is needed to confirm a >25 C predicted reduction in cooling required to achieve an ultralow dark-current target suitable for faint spectral astronomical observations that are not otherwise possible. This reduction in dark current makes it possible to increase the integration time of the imaging sensor, thus enabling a much higher near-infrared (NIR) sensitivity than is possible with current technology. As a result, extremely faint phenomena and NIR signals emitted from distant celestial objects can be now observed and imaged (such as the dynamics of redshifting galaxies, and spectral measurements on extra-solar planets in search of water and bio-markers) that were not previously possible. In addition, the enhanced NIR sensitivity also directly benefits other NIR imaging applications, including drug and bomb detection, stand-off detection of improvised explosive devices (IED's), Raman spectroscopy and microscopy for life/physical science applications, and semiconductor product defect detection.

  13. Streamflow Observations From Cameras: Large-Scale Particle Image Velocimetry or Particle Tracking Velocimetry?

    Science.gov (United States)

    Tauro, F.; Piscopia, R.; Grimaldi, S.

    2017-12-01

    Image-based methodologies, such as large scale particle image velocimetry (LSPIV) and particle tracking velocimetry (PTV), have increased our ability to noninvasively conduct streamflow measurements by affording spatially distributed observations at high temporal resolution. However, progress in optical methodologies has not been paralleled by the implementation of image-based approaches in environmental monitoring practice. We attribute this fact to the sensitivity of LSPIV, by far the most frequently adopted algorithm, to visibility conditions and to the occurrence of visible surface features. In this work, we test both LSPIV and PTV on a data set of 12 videos captured in a natural stream wherein artificial floaters are homogeneously and continuously deployed. Further, we apply both algorithms to a video of a high flow event on the Tiber River, Rome, Italy. In our application, we propose a modified PTV approach that only takes into account realistic trajectories. Based on our findings, LSPIV largely underestimates surface velocities with respect to PTV in both favorable (12 videos in a natural stream) and adverse (high flow event in the Tiber River) conditions. On the other hand, PTV is in closer agreement than LSPIV with benchmark velocities in both experimental settings. In addition, the accuracy of PTV estimations can be directly related to the transit of physical objects in the field of view, thus providing tangible data for uncertainty evaluation.

  14. Pea Streak Virus Recorded in Europe

    Czech Academy of Sciences Publication Activity Database

    Sarkisova, Tatiana; Bečková, M.; Fránová, Jana; Petrzik, Karel

    2016-01-01

    Roč. 52, č. 3 (2016), s. 164-166 ISSN 1212-2580 R&D Projects: GA MZe QH71145 Institutional support: RVO:60077344 Keywords : Pea streak virus * alfalfa * carlavirus * partial sequence Subject RIV: EE - Microbiology, Virology Impact factor: 0.742, year: 2016

  15. Nondipole effects in attosecond photoelectron streaking

    DEFF Research Database (Denmark)

    Spiewanowski, Maciek; Madsen, Lars Bojer

    2012-01-01

    The influence of nondipole terms on the time delay in photoionization by an extreme-ultraviolet attosecond pulse in the presence of a near-infrared femtosecond laser pulse from 1s, 2s, and 2p states in hydrogen is investigated. In this attosecond photoelectron streaking process, the relative...

  16. Atomic and molecular phases through attosecond streaking

    DEFF Research Database (Denmark)

    Baggesen, Jan Conrad; Madsen, Lars Bojer

    2011-01-01

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

  17. Mechanism for propagation of the step leader of streak lightning

    International Nuclear Information System (INIS)

    Golubev, A.I.; Zolotovskil, V.I.; Ivanovskil, A.V.

    1992-01-01

    A hypothetical scheme for the development of the step leader of streak lightning is discussed. The mathematical problem of modeling the propagation of the leader in this scheme is stated. The main parameters of the leader are estimated: the length and propagation velocity of the step, the average propagation velocity, etc. This is compared with data from observations in nature. The propagation of the leader is simulated numerically. Results of the calculation are presented for two 'flashes' of the step leader. 25 refs., 6 figs

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

    Science.gov (United States)

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

    2017-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-10-09

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

  20. Simultaneous streak and frame interferometry for electron density measurements of laser produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, H. J., E-mail: hjquevedo@utexas.edu; McCormick, M.; Wisher, M.; Bengtson, Roger D.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)

    2016-01-15

    A system of two collinear probe beams with different wavelengths and pulse durations was used to capture simultaneously snapshot interferograms and streaked interferograms of laser produced plasmas. The snapshots measured the two dimensional, path-integrated, electron density on a charge-coupled device while the radial temporal evolution of a one dimensional plasma slice was recorded by a streak camera. This dual-probe combination allowed us to select plasmas that were uniform and axisymmetric along the laser direction suitable for retrieving the continuous evolution of the radial electron density of homogeneous plasmas. Demonstration of this double probe system was done by measuring rapidly evolving plasmas on time scales less than 1 ns produced by the interaction of femtosecond, high intensity, laser pulses with argon gas clusters. Experiments aimed at studying homogeneous plasmas from high intensity laser-gas or laser-cluster interaction could benefit from the use of this probing scheme.

  1. Observation of the dynamic movement of fragmentations by high-speed camera and high-speed video

    Science.gov (United States)

    Suk, Chul-Gi; Ogata, Yuji; Wada, Yuji; Katsuyama, Kunihisa

    1995-05-01

    The experiments of blastings using mortal concrete blocks and model concrete columns were carried out in order to obtain technical information on fragmentation caused by the blasting demolition. The dimensions of mortal concrete blocks were 1,000 X 1,000 X 1,000 mm. Six kinds of experimental blastings were carried out using mortal concrete blocks. In these experiments precision detonators and No. 6 electric detonators with 10 cm detonating fuse were used and discussed the control of fragmentation. As the results of experiment it was clear that the flying distance of fragmentation can be controlled using a precise blasting system. The reinforced concrete model columns for typical apartment houses in Japan were applied to the experiments. The dimension of concrete test column was 800 X 800 X 2400 mm and buried 400 mm in the ground. The specified design strength of the concrete was 210 kgf/cm2. These columns were exploded by the blasting with internal loading of dynamite. The fragmentation were observed by two kinds of high speed camera with 500 and 2000 FPS and a high speed video with 400 FPS. As one of the results in the experiments, the velocity of fragmentation, blasted 330 g of explosive with the minimum resisting length of 0.32 m, was measured as much as about 40 m/s.

  2. CRED Fish Observations from Stereo Video Cameras on a SeaBED AUV collected around Tutuila, American Samoa in 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Black and white imagery were collected using a stereo pair of underwater video cameras mounted on a SeaBED autonomous underwater vehicle (AUV) and deployed around...

  3. Cold-water coral distributions in the drake passage area from towed camera observations--initial interpretations.

    Directory of Open Access Journals (Sweden)

    Rhian G Waller

    Full Text Available Seamounts are unique deep-sea features that create habitats thought to have high levels of endemic fauna, productive fisheries and benthic communities vulnerable to anthropogenic impacts. Many seamounts are isolated features, occurring in the high seas, where access is limited and thus biological data scarce. There are numerous seamounts within the Drake Passage (Southern Ocean, yet high winds, frequent storms and strong currents make seafloor sampling particularly difficult. As a result, few attempts to collect biological data have been made, leading to a paucity of information on benthic habitats or fauna in this area, particularly those on primarily hard-bottom seamounts and ridges. During a research cruise in 2008 six locations were examined (two on the Antarctic margin, one on the Shackleton Fracture Zone, and three on seamounts within the Drake Passage, using a towed camera with onboard instruments to measure conductivity, temperature, depth and turbidity. Dominant fauna and bottom type were categorized from 200 randomized photos from each location. Cold-water corals were present in high numbers in habitats both on the Antarctic margin and on the current swept seamounts of the Drake Passage, though the diversity of orders varied. Though the Scleractinia (hard corals were abundant on the sedimented margin, they were poorly represented in the primarily hard-bottom areas of the central Drake Passage. The two seamount sites and the Shackleton Fracture Zone showed high numbers of stylasterid (lace and alcyonacean (soft corals, as well as large numbers of sponges. Though data are preliminary, the geological and environmental variability (particularly in temperature between sample sites may be influencing cold-water coral biogeography in this region. Each area observed also showed little similarity in faunal diversity with other sites examined for this study within all phyla counted. This manuscript highlights how little is understood of these

  4. Cold-Water Coral Distributions in the Drake Passage Area from Towed Camera Observations – Initial Interpretations

    Science.gov (United States)

    Waller, Rhian G.; Scanlon, Kathryn M.; Robinson, Laura F.

    2011-01-01

    Seamounts are unique deep-sea features that create habitats thought to have high levels of endemic fauna, productive fisheries and benthic communities vulnerable to anthropogenic impacts. Many seamounts are isolated features, occurring in the high seas, where access is limited and thus biological data scarce. There are numerous seamounts within the Drake Passage (Southern Ocean), yet high winds, frequent storms and strong currents make seafloor sampling particularly difficult. As a result, few attempts to collect biological data have been made, leading to a paucity of information on benthic habitats or fauna in this area, particularly those on primarily hard-bottom seamounts and ridges. During a research cruise in 2008 six locations were examined (two on the Antarctic margin, one on the Shackleton Fracture Zone, and three on seamounts within the Drake Passage), using a towed camera with onboard instruments to measure conductivity, temperature, depth and turbidity. Dominant fauna and bottom type were categorized from 200 randomized photos from each location. Cold-water corals were present in high numbers in habitats both on the Antarctic margin and on the current swept seamounts of the Drake Passage, though the diversity of orders varied. Though the Scleractinia (hard corals) were abundant on the sedimented margin, they were poorly represented in the primarily hard-bottom areas of the central Drake Passage. The two seamount sites and the Shackleton Fracture Zone showed high numbers of stylasterid (lace) and alcyonacean (soft) corals, as well as large numbers of sponges. Though data are preliminary, the geological and environmental variability (particularly in temperature) between sample sites may be influencing cold-water coral biogeography in this region. Each area observed also showed little similarity in faunal diversity with other sites examined for this study within all phyla counted. This manuscript highlights how little is understood of these isolated

  5. Galaxy formation in the reionization epoch as hinted by Wide Field Camera 3 observations of the Hubble Ultra Deep Field

    International Nuclear Information System (INIS)

    Yan Haojing; Windhorst, Rogier A.; Cohen, Seth H.; Hathi, Nimish P.; Ryan, Russell E.; O'Connell, Robert W.; McCarthy, Patrick J.

    2010-01-01

    We present a large sample of candidate galaxies at z ∼ 7-10, selected in the Hubble Ultra Deep Field using the new observations of the Wide Field Camera 3 that was recently installed on the Hubble Space Telescope. Our sample is composed of 20 z 850 -dropouts (four new discoveries), 15 Y 105 -dropouts (nine new discoveries) and 20 J 125 -dropouts (all new discoveries). The surface densities of the z 850 -dropouts are close to what was predicted by earlier studies, however, those of the Y 105 - and J 125 -dropouts are quite unexpected. While no Y 105 - or J 125 -dropouts have been found at AB ≤ 28.0 mag, their surface densities seem to increase sharply at fainter levels. While some of these candidates seem to be close to foreground galaxies and thus could possibly be gravitationally lensed, the overall surface densities after excluding such cases are still much higher than what would be expected if the luminosity function does not evolve from z ∼ 7 to 10. Motivated by such steep increases, we tentatively propose a set of Schechter function parameters to describe the luminosity functions at z ∼ 8 and 10. As compared to their counterpart at z ∼ 7, here L * decreases by a factor of ∼ 6.5 and φ * increases by a factor of 17-90. Although such parameters are not yet demanded by the existing observations, they are allowed and seem to agree with the data better than other alternatives. If these luminosity functions are still valid beyond our current detection limit, this would imply a sudden emergence of a large number of low-luminosity galaxies when looking back in time to z ∼ 10, which, while seemingly exotic, would naturally fit in the picture of the cosmic hydrogen reionization. These early galaxies could easily account for the ionizing photon budget required by the reionization, and they would imply that the global star formation rate density might start from a very high value at z ∼ 10, rapidly reach the minimum at z ∼ 7, and start to rise again

  6. MULTIMODAL IMAGING OF ANGIOID STREAKS ASSOCIATED WITH TURNER SYNDROME.

    Science.gov (United States)

    Chiu, Bing Q; Tsui, Edmund; Hussnain, Syed Amal; Barbazetto, Irene A; Smith, R Theodore

    2018-02-13

    To report multimodal imaging in a novel case of angioid streaks in a patient with Turner syndrome with 10-year follow-up. Case report of a patient with Turner syndrome and angioid streaks followed at Bellevue Hospital Eye Clinic from 2007 to 2017. Fundus photography, fluorescein angiography, and optical coherence tomography angiography were obtained. Angioid streaks with choroidal neovascularization were noted in this patient with Turner syndrome without other systemic conditions previously correlated with angioid streaks. We report a case of angioid streaks with choroidal neovascularization in a patient with Turner syndrome. We demonstrate that angioid streaks, previously associated with pseudoxanthoma elasticum, Ehlers-Danlos syndrome, Paget disease of bone, and hemoglobinopathies, may also be associated with Turner syndrome, and may continue to develop choroidal neovascularization, suggesting the need for careful ophthalmic examination in these patients.

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

    Science.gov (United States)

    Park, Sun-Youp; Choi, Jin; Roh, Dong-Goo; Park, Maru; Jo, Jung Hyun; Yim, Hong-Suh; Park, Young-Sik; Bae, Young-Ho; Park, Jang-Hyun; Moon, Hong-Kyu; Choi, Young-Jun; Cho, Sungki; Choi, Eun-Jung

    2016-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

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

  9. X-ray streak crystal spectography

    International Nuclear Information System (INIS)

    Kauffman, R.L.; Brown, T.; Medecki, H.

    1983-01-01

    We have built an x-ray streaked crystal spectrograph for making time-resolved x-ray spectral measurements. This instrument can access Bragg angles from 11 0 to 38 0 and x-ray spectra from 200 eV to greater than 10 keV. We have demonstrated resolving powers, E/δE > 200 at 1 keV and time resolution less than 20 psec. A description of the instrument and an example of the data is given

  10. Approaches to diagnosis and detection of cassava brown streak ...

    African Journals Online (AJOL)

    Cassava brown streak disease (CBSD) has been a problem in the East African coastal cassava growing areas for more than 70 years. The disease is caused by successful infection with Cassava Brown Streak Virus (CBSV) (Family, Potyviridae: Genus, Ipomovirus). Diagnosis of CBSD has for long been primarily leaf ...

  11. Pedicle streaking: A novel and simple aid in pedicle positioning in free tissue transfer

    Directory of Open Access Journals (Sweden)

    Aditya Aggarwal

    2015-01-01

    Full Text Available Introduction: The pedicle positioning in free tissue transfer is critical to its success. Long thin pedicles are especially prone to this complication where even a slight twist in the perforator can result in flap loss. Pedicles passing through the long tunnels are similarly at risk. Streaking the pedicle with methylene blue is a simple and safe method which increases the safety of free tissue transfer. Materials and Methods: Once the flap is islanded on the pedicle and the vascularity of the flap is confirmed, the pedicle is streaked with methylene blue dye at a distance of 6-7 mm. The streaking starts from the origin of the vessels and continued distally on to the under surface of flap to mark the complete course of the pedicle in alignment. The presence of streaking in some parts and not in rest indicates twist in the pedicle. Observation and Results: Four hundred and sixty five free flaps have been done at our centre in the last 5 years. The overall success rate of free flaps is 95.3% (22 free flap failures. There has not been a single case of pedicle twist leading to flap congestion and failure. Conclusion: This simple and novel method is very reliable for pedicle positioning avoiding any twist necessary for successful free tissue transfer.

  12. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, Ul; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is replaceably mounted in the ray inlet opening of the camera, while the others are placed on separate supports. Supports are swingably mounted upon a column one above the other

  13. Gamma camera

    International Nuclear Information System (INIS)

    Schlosser, P.A.; Steidley, J.W.

    1980-01-01

    The design of a collimation system for a gamma camera for use in nuclear medicine is described. When used with a 2-dimensional position sensitive radiation detector, the novel system can produce superior images than conventional cameras. The optimal thickness and positions of the collimators are derived mathematically. (U.K.)

  14. Picosecond camera

    International Nuclear Information System (INIS)

    Decroisette, Michel

    A Kerr cell activated by infrared pulses of a model locked Nd glass laser, acts as an ultra-fast and periodic shutter, with a few p.s. opening time. Associated with a S.T.L. camera, it gives rise to a picosecond camera allowing us to study very fast effects [fr

  15. Invariant Observer-Based State Estimation for Micro-Aerial Vehicles in GPS-Denied Indoor Environments Using an RGB-D Camera and MEMS Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Dachuan Li

    2015-04-01

    Full Text Available This paper presents a non-linear state observer-based integrated navigation scheme for estimating the attitude, position and velocity of micro aerial vehicles (MAV operating in GPS-denied indoor environments, using the measurements from low-cost MEMS (micro electro-mechanical systems inertial sensors and an RGB-D camera. A robust RGB-D visual odometry (VO approach was developed to estimate the MAV’s relative motion by extracting and matching features captured by the RGB-D camera from the environment. The state observer of the RGB-D visual-aided inertial navigation was then designed based on the invariant observer theory for systems possessing symmetries. The motion estimates from the RGB-D VO were fused with inertial and magnetic measurements from the onboard MEMS sensors via the state observer, providing the MAV with accurate estimates of its full six degree-of-freedom states. Implementations on a quadrotor MAV and indoor flight test results demonstrate that the resulting state observer is effective in estimating the MAV’s states without relying on external navigation aids such as GPS. The properties of computational efficiency and simplicity in gain tuning make the proposed invariant observer-based navigation scheme appealing for actual MAV applications in indoor environments.

  16. Time-resolved brightness measurements by streaking

    Science.gov (United States)

    Torrance, Joshua S.; Speirs, Rory W.; McCulloch, Andrew J.; Scholten, Robert E.

    2018-03-01

    Brightness is a key figure of merit for charged particle beams, and time-resolved brightness measurements can elucidate the processes involved in beam creation and manipulation. Here we report on a simple, robust, and widely applicable method for the measurement of beam brightness with temporal resolution by streaking one-dimensional pepperpots, and demonstrate the technique to characterize electron bunches produced from a cold-atom electron source. We demonstrate brightness measurements with 145 ps temporal resolution and a minimum resolvable emittance of 40 nm rad. This technique provides an efficient method of exploring source parameters and will prove useful for examining the efficacy of techniques to counter space-charge expansion, a critical hurdle to achieving single-shot imaging of atomic scale targets.

  17. Observations of sea-ice conditions in the Antarctic coastal region using ship-board video cameras

    Directory of Open Access Journals (Sweden)

    Haruhito Shimoda

    1997-03-01

    Full Text Available During the 30th, 31st, and 32nd Japanese Antarctic Research Expeditions (JARE-30,JARE-31,and JARE-32, sea-ice conditions were recorded by video camera on board the SHIRASE. Then, the sea-ice images were used to estimate compactness and thickness quantitatively. Analyzed legs are those toward Breid Bay and from Breid Bay to Syowa Station during JARE-30 and JARE-31,and those toward the Prince Olav Coast, from the Prince Olav Coast to Breid Bay, and from Breid Bay to Syowa Station during JARE-32. The results show yearly variations of ice compactness and thickness, latitudinal variations of thickness, and differences in thickness histograms between JARE-30 and JARE-32 in Lutzow-Holm Bay. Albedo values were measured simultaneously by a shortwave radiometer. These values are proportional to those of ice compactness. Finally, we examined the relationship between ice compactness and vertical gradient of air temperature above sea ice.

  18. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, U.; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is mounted in the ray inlet opening of the camera, while the others are placed on separate supports. The supports are swingably mounted upon a column one above the other through about 90 0 to a collimator exchange position. Each of the separate supports is swingable to a vertically aligned position, with limiting of the swinging movement and positioning of the support at the desired exchange position. The collimators are carried on the supports by means of a series of vertically disposed coil springs. Projections on the camera are movable from above into grooves of the collimator at the exchange position, whereupon the collimator is turned so that it is securely prevented from falling out of the camera head

  19. HUBBLE SPACE TELESCOPE/NEAR-INFRARED CAMERA AND MULTI-OBJECT SPECTROMETER OBSERVATIONS OF THE GLIMPSE9 STELLAR CLUSTER

    International Nuclear Information System (INIS)

    Messineo, Maria; Figer, Donald F.; Davies, Ben; Trombley, Christine; Kudritzki, R. P.; Rich, R. Michael; MacKenty, John

    2010-01-01

    We present Hubble Space Telescope/Near-Infrared Camera and Multi-Object Spectrometer photometry, and low-resolution K-band spectra of the GLIMPSE9 stellar cluster. The newly obtained color-magnitude diagram shows a cluster sequence with H - K S = ∼1 mag, indicating an interstellar extinction A K s = 1.6 ± 0.2 mag. The spectra of the three brightest stars show deep CO band heads, which indicate red supergiants with spectral type M1-M2. Two 09-B2 supergiants are also identified, which yield a spectrophotometric distance of 4.2 ± 0.4 kpc. Presuming that the population is coeval, we derive an age between 15 and 27 Myr, and a total cluster mass of 1600 ± 400 M sun , integrated down to 1 M sun . In the vicinity of GLIMPSE9 are several H II regions and supernova remnants, all of which (including GLIMPSE9) are probably associated with a giant molecular cloud (GMC) in the inner galaxy. GLIMPSE9 probably represents one episode of massive star formation in this GMC. We have identified several other candidate stellar clusters of the same complex.

  20. THE SIZE EVOLUTION OF PASSIVE GALAXIES: OBSERVATIONS FROM THE WIDE-FIELD CAMERA 3 EARLY RELEASE SCIENCE PROGRAM

    International Nuclear Information System (INIS)

    Ryan, R. E. Jr.; McCarthy, P. J.; Cohen, S. H.; Rutkowski, M. J.; Mechtley, M. R.; Windhorst, R. A.; Yan, H.; Hathi, N. P.; Koekemoer, A. M.; Bond, H. E.; Bushouse, H.; O'Connell, R. W.; Balick, B.; Calzetti, D.; Crockett, R. M.; Disney, M.; Dopita, M. A.; Frogel, J. A.; Hall, D. N. B.; Holtzman, J. A.

    2012-01-01

    We present the size evolution of passively evolving galaxies at z ∼ 2 identified in Wide-Field Camera 3 imaging from the Early Release Science program. Our sample was constructed using an analog to the passive BzK galaxy selection criterion, which isolates galaxies with little or no ongoing star formation at z ∼> 1.5. We identify 30 galaxies in ∼40 arcmin 2 to H obs ∼ * ∼ 10 11 M ☉ ) undergo the strongest evolution from z ∼ 2 to the present. Parameterizing the size evolution as (1 + z) –α , we find a tentative scaling of α ≈ (– 0.6 ± 0.7) + (0.9 ± 0.4)log (M * /10 9 M ☉ ), where the relatively large uncertainties reflect the poor sampling in stellar mass due to the low numbers of high-redshift systems. We discuss the implications of this result for the redshift evolution of the M * -R e relation for red galaxies.

  1. Ultra-fast framing camera tube

    Science.gov (United States)

    Kalibjian, Ralph

    1981-01-01

    An electronic framing camera tube features focal plane image dissection and synchronized restoration of the dissected electron line images to form two-dimensional framed images. Ultra-fast framing is performed by first streaking a two-dimensional electron image across a narrow slit, thereby dissecting the two-dimensional electron image into sequential electron line images. The dissected electron line images are then restored into a framed image by a restorer deflector operated synchronously with the dissector deflector. The number of framed images on the tube's viewing screen is equal to the number of dissecting slits in the tube. The distinguishing features of this ultra-fast framing camera tube are the focal plane dissecting slits, and the synchronously-operated restorer deflector which restores the dissected electron line images into a two-dimensional framed image. The framing camera tube can produce image frames having high spatial resolution of optical events in the sub-100 picosecond range.

  2. Using a slit lamp-mounted digital high-speed camera for dynamic observation of phakic lenses during eye movements: a pilot study

    Directory of Open Access Journals (Sweden)

    Leitritz MA

    2014-07-01

    Full Text Available Martin Alexander Leitritz, Focke Ziemssen, Karl Ulrich Bartz-Schmidt, Bogomil Voykov Centre for Ophthalmology, University Eye Hospital, Eberhard Karls University of Tübingen, Tübingen, Germany Purpose: To evaluate a digital high-speed camera combined with digital morphometry software for dynamic measurements of phakic intraocular lens movements to observe kinetic influences, particularly in fast direction changes and at lateral end points. Materials and methods: A high-speed camera taking 300 frames per second observed movements of eight iris-claw intraocular lenses and two angle-supported intraocular lenses. Standardized saccades were performed by the patients to trigger mass inertia with lens position changes. Freeze images with maximum deviation were used for digital software-based morphometry analysis with ImageJ.Results: Two eyes from each of five patients (median age 32 years, range 28–45 years without findings other than refractive errors were included. The high-speed images showed sufficient usability for further morphometric processing. In the primary eye position, the median decentrations downward and in a lateral direction were -0.32 mm (range -0.69 to 0.024 and 0.175 mm (range -0.37 to 0.45, respectively. Despite the small sample size of asymptomatic patients, we found a considerable amount of lens dislocation. The median distance amplitude during eye movements was 0.158 mm (range 0.02–0.84. There was a slight positive corrlation (r=0.39, P<0.001 between the grade of deviation in the primary position and the distance increase triggered by movements.Conclusion: With the use of a slit lamp-mounted high-speed camera system and morphometry software, observation and objective measurements of iris-claw intraocular lenses and angle-supported intraocular lenses movements seem to be possible. Slight decentration in the primary position might be an indicator of increased lens mobility during kinetic stress during eye movements

  3. The turbulent life of juvenile icebergs: Observations from an array of high-rate time-lapse cameras in LeConte Bay, Alaska

    Science.gov (United States)

    Kienholz, C.; Amundson, J. M.; Jackson, R. H.; Motyka, R. J.; Nash, J. D.; Sutherland, D.

    2017-12-01

    Tidewater glacier behavior is driven by poorly understood processes occurring at the ice-ocean interface, including sedimentation and erosion, iceberg calving, and submarine melting. These processes are inherently difficult to observe, calling for innovative field techniques and numerical models. As part of a multi-year field effort to constrain ocean-glacier heat and mass exchange, we deployed an array of high-rate time-lapse cameras (sampling intervals between 15 seconds and 2 minutes) to monitor the terminus of LeConte Glacier and its proglacial fjord. The camera array has operated continuously for more than a year. Our high sampling rates enable tracking of iceberg motion with optical flow algorithms, which have been used widely in computer vision but less so in glaciology and oceanography. Such algorithms track individual features (e.g., corners of icebergs), which is ideal for iceberg-rich fjords, where motion can vary substantially over short temporal and spatial scales (e.g., due to complex surface currents or different iceberg sizes). We process our data to quantify subdaily to seasonal patterns in surface currents and relate them to forcing from tides, wind, and glacier runoff. Flow is most variable close to the glacier terminus due to frequent calving events and turbulent plume dynamics. Farther down fjord, more consistent patterns emerge, driven by tides, wind, and runoff and altered by fjord geometry. Our tracking results compare favorably to and complement our Acoustic Doppler Current Profiler measurements from boats and moorings. Given their high spatial and temporal resolution, our observations will place important surface constraints on forthcoming hydrodynamic modeling efforts. The deployment of the cameras in a harsh environment and the corresponding image processing provided an opportunity to test hardware and software thoroughly, which will prove useful for similar systems at other glaciers.

  4. Heard Island and McDonald Islands Acoustic Plumes: Split-beam Echo sounder and Deep Tow Camera Observations of Gas Seeps on the Central Kerguelen Plateau

    Science.gov (United States)

    Watson, S. J.; Spain, E. A.; Coffin, M. F.; Whittaker, J. M.; Fox, J. M.; Bowie, A. R.

    2016-12-01

    Heard and McDonald islands (HIMI) are two active volcanic edifices on the Central Kerguelen Plateau. Scientists aboard the Heard Earth-Ocean-Biosphere Interactions voyage in early 2016 explored how this volcanic activity manifests itself near HIMI. Using Simrad EK60 split-beam echo sounder and deep tow camera data from RV Investigator, we recorded the distribution of seafloor emissions, providing the first direct evidence of seabed discharge around HIMI, mapping >244 acoustic plume signals. Northeast of Heard, three distinct plume clusters are associated with bubbles (towed camera) and the largest directly overlies a sub-seafloor opaque zone (sub-bottom profiler) with >140 zones observed within 6.5 km. Large temperature anomalies did not characterize any of the acoustic plumes where temperature data were recorded. We therefore suggest that these plumes are cold methane seeps. Acoustic properties - mean volume backscattering and target strength - and morphology - height, width, depth to surface - of plumes around McDonald resembled those northeast of Heard, also suggesting gas bubbles. We observed no bubbles on extremely limited towed camera data around McDonald; however, visibility was poor. The acoustic response of the plumes at different frequencies (120 kHz vs. 18 kHz), a technique used to classify water column scatterers, differed between HIMI, suggestiing dissimilar target size (bubble radii) distributions. Environmental context and temporal characteristics of the plumes differed between HIMI. Heard plumes were concentrated on flat, sediment rich plains, whereas around McDonald plumes emanated from sea knolls and mounds with hard volcanic seafloor. The Heard plumes were consistent temporally, while the McDonald plumes varied temporally possibly related to tides or subsurface processes. Our data and analyses suggest that HIMI acoustic plumes were likely caused by gas bubbles; however, the bubbles may originate from two or more distinct processes.

  5. Postprocessing method to clean up streaks due to noisy detectors

    International Nuclear Information System (INIS)

    Tuy, H.K.; Mattson, R.A.

    1990-01-01

    This paper reports that occasionally, one of the thousands of detectors in a CT scanner will intermittently produce erroneous data, creating streaks in the reconstructed image. The authors propose a method to identify and clean up the streaks automatically. To find the rays along which the data values are bad, a binary image registering the edges of the original image is created. Forward projection is applied to the binary image to single out edges along rays. Data along views containing the identified bad rays are estimated by means of forward projecting the original image. Back projection of the negative of the estimated convolved data along these views onto the streaky image will remove streaks from the image. Image enhancement is achieved by means of back projecting the convolved data estimated from the image after the streak removal along views of bad rays

  6. traits and resistance to maize streak virus disease in kenya

    African Journals Online (AJOL)

    African Crop Science Journal, Vol. 14. No. 4, pp. ... Kenya Agricultural Research Institute, Muguga-South, P.O. Box 30148, Nairobi, Kenya .... streak disease has been identified in various maize recycling and development of pure-lines at.

  7. THE SIZE EVOLUTION OF PASSIVE GALAXIES: OBSERVATIONS FROM THE WIDE-FIELD CAMERA 3 EARLY RELEASE SCIENCE PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, R. E. Jr. [Physics Department, University of California, Davis, CA 95616 (United States); McCarthy, P. J. [Observatories of the Carnegie Institute of Washington, Pasadena, CA 91101 (United States); Cohen, S. H.; Rutkowski, M. J.; Mechtley, M. R.; Windhorst, R. A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Yan, H. [Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Hathi, N. P. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Koekemoer, A. M.; Bond, H. E.; Bushouse, H. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); O' Connell, R. W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Crockett, R. M. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Disney, M. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, M. A. [Research School of Astronomy and Astrophysics, The Australian National University, Weston Creek, ACT 2611 (Australia); Frogel, J. A. [Galaxies Unlimited, Lutherville, MD 21093 (United States); Hall, D. N. B. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Holtzman, J. A., E-mail: rryan@physics.ucdavis.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); and others

    2012-04-10

    We present the size evolution of passively evolving galaxies at z {approx} 2 identified in Wide-Field Camera 3 imaging from the Early Release Science program. Our sample was constructed using an analog to the passive BzK galaxy selection criterion, which isolates galaxies with little or no ongoing star formation at z {approx}> 1.5. We identify 30 galaxies in {approx}40 arcmin{sup 2} to H < 25 mag. By fitting the 10-band Hubble Space Telescope photometry from 0.22 {mu}m {approx}< {lambda}{sub obs} {approx}< 1.6 {mu}m with stellar population synthesis models, we simultaneously determine photometric redshift, stellar mass, and a bevy of other population parameters. Based on the six galaxies with published spectroscopic redshifts, we estimate a typical redshift uncertainty of {approx}0.033(1 + z). We determine effective radii from Sersic profile fits to the H-band image using an empirical point-spread function. By supplementing our data with published samples, we propose a mass-dependent size evolution model for passively evolving galaxies, where the most massive galaxies (M{sub *} {approx} 10{sup 11} M{sub Sun }) undergo the strongest evolution from z {approx} 2 to the present. Parameterizing the size evolution as (1 + z){sup -{alpha}}, we find a tentative scaling of {alpha} Almost-Equal-To (- 0.6 {+-} 0.7) + (0.9 {+-} 0.4)log (M{sub *}/10{sup 9} M{sub Sun }), where the relatively large uncertainties reflect the poor sampling in stellar mass due to the low numbers of high-redshift systems. We discuss the implications of this result for the redshift evolution of the M{sub *}-R{sub e} relation for red galaxies.

  8. Analysis of the three-dimensional trajectories of dusts observed with a stereoscopic fast framing camera in the Large Helical Device

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, M., E-mail: shoji@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Gifu (Japan); Masuzaki, S. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Gifu (Japan); Tanaka, Y. [Kanazawa University, Kakuma, Kanazawa 920-1192 (Japan); Pigarov, A.Yu.; Smirnov, R.D. [University of California at San Diego, La Jolla, CA 92093 (United States); Kawamura, G.; Uesugi, Y.; Yamada, H. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Gifu (Japan)

    2015-08-15

    The three-dimensional trajectories of dusts have been observed with two stereoscopic fast framing cameras installed in upper and outer viewports in the Large Helical Device (LHD). It shows that the dust trajectories locate in divertor legs and an ergodic layer around the main plasma confinement region. While it is found that most of the dusts approximately move along the magnetic field lines with acceleration, there are some dusts which have sharply curved trajectories crossing over the magnetic field lines. A dust transport simulation code was modified to investigate the dust trajectories in fully three dimensional geometries such as LHD plasmas. It can explain the general trend of most of observed dust trajectories by the effect of the plasma flow in the peripheral plasma. However, the behavior of the some dusts with sharply curved trajectories is not consistent with the simulations.

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

    Directory of Open Access Journals (Sweden)

    De-xi CHEN

    2013-07-01

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

  10. Cassava brown streak disease in Rwanda, the associated viruses and disease phenotypes.

    Science.gov (United States)

    Munganyinka, E; Ateka, E M; Kihurani, A W; Kanyange, M C; Tairo, F; Sseruwagi, P; Ndunguru, J

    2018-02-01

    Cassava brown streak disease (CBSD) was first observed on cassava ( Manihot esculenta ) in Rwanda in 2009. In 2014 eight major cassava-growing districts in the country were surveyed to determine the distribution and variability of symptom phenotypes associated with CBSD, and the genetic diversity of cassava brown streak viruses. Distribution of the CBSD symptom phenotypes and their combinations varied greatly between districts, cultivars and their associated viruses. The symptoms on leaf alone recorded the highest (32.2%) incidence, followed by roots (25.7%), leaf + stem (20.3%), leaf + root (10.4%), leaf + stem + root (5.2%), stem + root (3.7%), and stem (2.5%) symptoms. Analysis by RT-PCR showed that single infections of Ugandan cassava brown streak virus (UCBSV) were most common (74.2% of total infections) and associated with all the seven phenotypes studied. Single infections of Cassava brown streak virus (CBSV) were predominant (15.3% of total infections) in CBSD-affected plants showing symptoms on stems alone. Mixed infections (CBSV + UCBSV) comprised 10.5% of total infections and predominated in the combinations of leaf + stem + root phenotypes. Phylogenetic analysis and the estimates of evolutionary divergence, using partial sequences (210 nt) of the coat protein gene, revealed that in Rwanda there is one type of CBSV and an indication of diverse UCBSV. This study is the first to report the occurrence and distribution of both CBSV and UCBSV based on molecular techniques in Rwanda.

  11. ANTIOXIDANT EFFECTS OF L-SERINE AGAINST FATTY STREAK FORMATION IN HYPERCHOLESTEROLEMIC ANIMALS

    Directory of Open Access Journals (Sweden)

    Ahmad Movahedian

    2010-12-01

    Full Text Available   Abstract INTRODUCTION: Peroxidation of blood lipoproteins is regarded as a key event in the development of atherosclerosis. Evidence suggests that oxidative modification of amino acids in low-density lipoprotein (LDL particles leads to its convert into an atherogenic form, which is taken up by macrophages. Therefore the reduction of oxidative modification of lipoproteins by increasing plasma antioxidant capacity may prevent cardiovascular disease. methods: In this study, the antioxidant and anti-fatty streak effects of L-serine were investigated in hypercholesterolemic rabbits. Rabbits were randomly divided into three groups which were fed high-cholesterol diet (hypercholesterolemic control group, high-cholesterol + L-serine diet (treatment group, and normal diet (control for twelve weeks and then blood samples were obtained to measure plasma cholesterol, triglyceride (TG, high-density lipoprotein (HDL, low-density lipoprotein (LDL, antioxidant capacity (AC, malondialdehyde (MDA, and conjugated dienes (CDS. Right and left coronary arteries were also obtained for histological evaluation. results: No significant difference was observed in plasma cholesterol, TG, HDL, LDL and CDS levels between treatment and hypercholesterolemic control groups (P>0.05. The levels of plasma MDA and AC were 0.29‌ µM and 56%, respectively in the treatment group which showed a significant change in comparison with hypercholesterolemic control groups (P<0.05. The mean size of produced fatty streak also showed significant reduction in the treatment group compared to the hypercholesterolemic group (P<0.05. CONCLUSIONS: The results showed that L-serine has antioxidant and anti-fatty streak effects without any influence on plasma lipid levels in hypercholesterolemic rabbits.     Keywords: Atherosclerosis, cholesterol, L-serine, antioxidant, lipids, fatty streak.

  12. Picosecond Streaked K-Shell Spectroscopy of Near Solid-Density Aluminum Plasmas

    Science.gov (United States)

    Stillman, C. R.; Nilson, P. M.; Ivancic, S. T.; Mileham, C.; Froula, D. H.; Golovkin, I. E.

    2016-10-01

    The thermal x-ray emission from rapidly heated solid targets containing a buried-aluminum layer was measured. The targets were driven by high-contrast 1 ω or 2 ω laser pulses at focused intensities up to 1 ×1019W/Wcm2 cm2 . A streaked x-ray spectrometer recorded the Al Heα and lithium-like satellite lines with 2-ps temporal resolution and moderate resolving power (E/E ΔE 700). Time-integrated measurements over the same spectral range were used to correct the streaked data for variations in photocathode sensitivity. Line widths and intensity ratios from the streaked data were interpreted using a collisional radiative atomic model to provide the average plasma conditions in the buried layer as a function of time. It was observed that the resonance line tends toward lower photon energies at high electron densities. The measured shifts will be compared to predicted shifts from Stark-operator calculations at the inferred plasma conditions. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944, the office of Fusion Energy Sciences Award Number DE-SC0012317, and the Stewardship Science Graduate Fellowship Grant Number DE-NA0002135.

  13. Scintillating camera

    International Nuclear Information System (INIS)

    Vlasbloem, H.

    1976-01-01

    The invention relates to a scintillating camera and in particular to an apparatus for determining the position coordinates of a light pulse emitting point on the anode of an image intensifier tube which forms part of a scintillating camera, comprising at least three photomultipliers which are positioned to receive light emitted by the anode screen on their photocathodes, circuit means for processing the output voltages of the photomultipliers to derive voltages that are representative of the position coordinates; a pulse-height discriminator circuit adapted to be fed with the sum voltage of the output voltages of the photomultipliers for gating the output of the processing circuit when the amplitude of the sum voltage of the output voltages of the photomultipliers lies in a predetermined amplitude range, and means for compensating the distortion introduced in the image on the anode screen

  14. Gamma camera

    International Nuclear Information System (INIS)

    Reiss, K.H.; Kotschak, O.; Conrad, B.

    1976-01-01

    A gamma camera with a simplified setup as compared with the state of engineering is described permitting, apart from good localization, also energy discrimination. Behind the usual vacuum image amplifier a multiwire proportional chamber filled with trifluorine bromium methane is connected in series. Localizing of the signals is achieved by a delay line, energy determination by means of a pulse height discriminator. With the aid of drawings and circuit diagrams, the setup and mode of operation are explained. (ORU) [de

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

    Directory of Open Access Journals (Sweden)

    Ilias Georgalas

    2008-12-01

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

  16. Orientation tuning of contrast masking caused by motion streaks.

    Science.gov (United States)

    Apthorp, Deborah; Cass, John; Alais, David

    2010-08-01

    We investigated whether the oriented trails of blur left by fast-moving dots (i.e., "motion streaks") effectively mask grating targets. Using a classic overlay masking paradigm, we varied mask contrast and target orientation to reveal underlying tuning. Fast-moving Gaussian blob arrays elevated thresholds for detection of static gratings, both monoptically and dichoptically. Monoptic masking at high mask (i.e., streak) contrasts is tuned for orientation and exhibits a similar bandwidth to masking functions obtained with grating stimuli (∼30 degrees). Dichoptic masking fails to show reliable orientation-tuned masking, but dichoptic masks at very low contrast produce a narrowly tuned facilitation (∼17 degrees). For iso-oriented streak masks and grating targets, we also explored masking as a function of mask contrast. Interestingly, dichoptic masking shows a classic "dipper"-like TVC function, whereas monoptic masking shows no dip and a steeper "handle". There is a very strong unoriented component to the masking, which we attribute to transiently biased temporal frequency masking. Fourier analysis of "motion streak" images shows interesting differences between dichoptic and monoptic functions and the information in the stimulus. Our data add weight to the growing body of evidence that the oriented blur of motion streaks contributes to the processing of fast motion signals.

  17. A compact large-format streak tube for imaging lidar

    Science.gov (United States)

    Hui, Dandan; Luo, Duan; Tian, Liping; Lu, Yu; Chen, Ping; Wang, Junfeng; Sai, Xiaofeng; Wen, Wenlong; Wang, Xing; Xin, Liwei; Zhao, Wei; Tian, Jinshou

    2018-04-01

    The streak tubes with a large effective photocathode area, large effective phosphor screen area, and high photocathode radiant sensitivity are essential for improving the field of view, depth of field, and detectable range of the multiple-slit streak tube imaging lidar. In this paper, a high spatial resolution, large photocathode area, and compact meshless streak tube with a spherically curved cathode and screen is designed and tested. Its spatial resolution reaches 20 lp/mm over the entire Φ28 mm photocathode working area, and the simulated physical temporal resolution is better than 30 ps. The temporal distortion in our large-format streak tube, which is shown to be a non-negligible factor, has a minimum value as the radius of curvature of the photocathode varies. Furthermore, the photocathode radiant sensitivity and radiant power gain reach 41 mA/W and 18.4 at the wavelength of 550 nm, respectively. Most importantly, the external dimensions of our streak tube are no more than Φ60 mm × 110 mm.

  18. Aerosol properties in the upper clouds of Venus from glory observations by the Venus Monitoring Camera (Venus Express mission)

    Science.gov (United States)

    Markiewicz, Wojciech J.; Petrova, Elena V.; Shalygina, Oksana S.

    2018-01-01

    From the angular positions of the glory features observed on the upper cloud deck of Venus in three VMC channels (at 0.365, 0.513, and 0.965 μm), the dominating sizes of cloud particles and their refractive indices have been retrieved, and their spatial and temporal variations have been analyzed. For this, the phase profiles of brightness were compared to the single-scattering phase functions of particles of different sizes, since diffuse multiple scattering in the clouds does not move the angular positions of the glory, which is produced by the single scattering by cloud particles, but only makes them less pronounced. We presented the measured phase profiles in two ways: they were built for individual images and for individual small regions observed in series of successive images. The analysis of the data of both types has yielded consistent results. The presently retrieved radii of cloud particle average approximately 1.0-1.2 μm (though some values reach 1.4 μm) and demonstrate a variable pattern versus latitude and local solar time (LST). The decrease of particle sizes at high latitudes (down to 0.6 μm at 60°S) earlier found from the 0.965-μm and partly 0.365-μm data has been definitely confirmed in the analysis of the data of all three channels considered. To obtain the consistent estimates of particle sizes from the UV glory maximum and minimum positions, we have to vary the effective variance of the particle sizes, while it was fixed constant in our previous studies. The twofold increase of this parameter (from 0.07 to 0.14) diminishes the estimates of particle sizes by 10-15%, while the effect on the retrieved refractive index is negligible. The obtained estimates of the refractive index are more or less uniformly distributed over the covered latitude and LST ranges, and most of them are higher than those of concentrated sulfuric acid solution. This confirms our previous result obtained only at 0.965 μm, and now we may state that the cases of a

  19. Streak artifacts on Kidney CT: Ionic vs nonionic contrast media

    International Nuclear Information System (INIS)

    Cho, Eun Ok; Kim, Won Hong; Jung, Myung Suk; Kim, Yong Hoon; Hur, Gham

    1993-01-01

    The authors reviewed findings of enhanced abdominal computed tomography (CT) scans to know the difference between a higher dose of conventional ionic contrast media(iothalamate meglumine) and a lower dose of a new, nonionic contrast material(ioversol). One hundred adult patients were divided into two groups. Each group consisted of 50 patients. Iothalamate meglumine and ioversol were intravenously administered in each group. The radio of the male to female in the former was 28:22, and the latter 29:21. We examine the degree of renal streak artifact and measure the Hounsfield number of urine in renal collecting system. There were significant differences of the degree of the streak artifact depending upon the osmolality of contrast media used and that was related with urine CT number(P value<0.005). We authors conclude that nonionic low osmolar contrast media is prone to cause streak artifacts and distortions of renal image than conventional ionic high osmolar contrast media

  20. The star formation histories of local group dwarf galaxies. I. Hubble space telescope/wide field planetary camera 2 observations

    Energy Technology Data Exchange (ETDEWEB)

    Weisz, Daniel R. [Department of Astronomy, University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Skillman, Evan D. [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Holtzman, Jon [Department of Astronomy, New Mexico State University, Box 30001, 1320 Frenger Street, Las Cruces, NM 88003 (United States); Gilbert, Karoline M.; Dalcanton, Julianne J.; Williams, Benjamin F., E-mail: drw@ucsc.edu [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States)

    2014-07-10

    We present uniformly measured star formation histories (SFHs) of 40 Local Group (LG) dwarf galaxies based on color-magnitude diagram (CMD) analysis from archival Hubble Space Telescope imaging. We demonstrate that accurate SFHs can be recovered from CMDs that do not reach the oldest main sequence turn-off (MSTO), but emphasize that the oldest MSTO is critical for precisely constraining the earliest epochs of star formation. We find that: (1) the average lifetime SFHs of dwarf spheroidals (dSphs) can be approximated by an exponentially declining SFH with τ ∼ 5 Gyr; (2) lower luminosity dSphs are less likely to have extended SFHs than more luminous dSphs; (3) the average SFHs of dwarf irregulars (dIrrs), transition dwarfs, and dwarf ellipticals can be approximated by the combination of an exponentially declining SFH (τ ∼ 3-4 Gyr) for lookback ages >10-12 Gyr ago and a constant SFH thereafter; (4) the observed fraction of stellar mass formed prior to z = 2 ranges considerably (80% for galaxies with M < 10{sup 5} M{sub ☉} to 30% for galaxies with M > 10{sup 7} M{sub ☉}) and is largely explained by environment; (5) the distinction between 'ultra-faint' and 'classical' dSphs is arbitrary; (6) LG dIrrs formed a significantly higher fraction of stellar mass prior to z = 2 than the Sloan Digital Sky Survey galaxies from Leitner and the SFHs from the abundance matching models of Behroozi et al. This may indicate higher than expected star formation efficiencies at early times in low mass galaxies. Finally, we provide all the SFHs in tabulated electronic format for use by the community.

  1. The star formation histories of local group dwarf galaxies. I. Hubble space telescope/wide field planetary camera 2 observations

    International Nuclear Information System (INIS)

    Weisz, Daniel R.; Dolphin, Andrew E.; Skillman, Evan D.; Holtzman, Jon; Gilbert, Karoline M.; Dalcanton, Julianne J.; Williams, Benjamin F.

    2014-01-01

    We present uniformly measured star formation histories (SFHs) of 40 Local Group (LG) dwarf galaxies based on color-magnitude diagram (CMD) analysis from archival Hubble Space Telescope imaging. We demonstrate that accurate SFHs can be recovered from CMDs that do not reach the oldest main sequence turn-off (MSTO), but emphasize that the oldest MSTO is critical for precisely constraining the earliest epochs of star formation. We find that: (1) the average lifetime SFHs of dwarf spheroidals (dSphs) can be approximated by an exponentially declining SFH with τ ∼ 5 Gyr; (2) lower luminosity dSphs are less likely to have extended SFHs than more luminous dSphs; (3) the average SFHs of dwarf irregulars (dIrrs), transition dwarfs, and dwarf ellipticals can be approximated by the combination of an exponentially declining SFH (τ ∼ 3-4 Gyr) for lookback ages >10-12 Gyr ago and a constant SFH thereafter; (4) the observed fraction of stellar mass formed prior to z = 2 ranges considerably (80% for galaxies with M < 10 5 M ☉ to 30% for galaxies with M > 10 7 M ☉ ) and is largely explained by environment; (5) the distinction between 'ultra-faint' and 'classical' dSphs is arbitrary; (6) LG dIrrs formed a significantly higher fraction of stellar mass prior to z = 2 than the Sloan Digital Sky Survey galaxies from Leitner and the SFHs from the abundance matching models of Behroozi et al. This may indicate higher than expected star formation efficiencies at early times in low mass galaxies. Finally, we provide all the SFHs in tabulated electronic format for use by the community.

  2. Measuring Dust Emission from the Mojave Desert (USA) by Daily Remote-Camera Observations and Wind-Erosion Measurements: Bearing on "Unseen" Sources and Global Dust Abundance

    Science.gov (United States)

    Reynolds, R. L.; Urban, F.; Goldstein, H. L.; Fulton, R.

    2017-12-01

    A large gap in understanding the effects of atmospheric dust at all spatial scales is uncertainty about how much and whence dust is emitted annually. Digital recording of dust emission at high spatial and temporal resolution would, together with periodic flux measurements, support improved estimates of local-scale dust flux where infrastructure could support remote internet enabled cameras. Such recording would also elucidate wind-erosion dynamics when combined with meteorological data. Remote camera recording of dust-emitting settings on and around Soda Lake (Mojave Desert) was conducted every 15 minutes during daylight between 10 Nov. 2010 and 31 Dec. 2016 and images uploaded to a web server. Examination of 135,000 images revealed frequent dust events, termed "dust days" when plumes obscured mountains beyond source areas. Such days averaged 68 (sd=10) per year (2011 through 2016). We examined satellite retrievals (MODIS, GOES) for dust events during six cloudless days of highest and longest duration dust emission but none were observed. From Apr. 2000 through May 2013, aeolian sediments collected at three sites were sampled and weighed. Estimates of the emitted mass of silt- and clay-size fractions were made on the basis of measured horizontal mass flux, particle sizes of sediment in collectors, and roughly determined areas of dust generation. Over this period, nearly 4 Tg yr-1 of dust (as particulate matter flood in the basin in late Dec. 2010 that deposited flood sediment across the lake basin. Increased emission was likely related to the availability of fresh, unanchored flood sediment. Within the Mojave and Great Basin deserts of North America, many settings akin to those at Soda Lake similarly emit dust that is rarely detected in satellite retrievals. These findings strongly imply that local and regional dust emissions from western North America are far underestimated and that, by extension to relatively small dust-source areas across all drylands, global

  3. Star Formation at z~6: i-Dropouts in the Advanced Camera for Surveys Guaranteed Time Observation Fields

    Science.gov (United States)

    Bouwens, R. J.; Illingworth, G. D.; Rosati, P.; Lidman, C.; Broadhurst, T.; Franx, M.; Ford, H. C.; Magee, D.; Benítez, N.; Blakeslee, J. P.; Meurer, G. R.; Clampin, M.; Hartig, G. F.; Ardila, D. R.; Bartko, F.; Brown, R. A.; Burrows, C. J.; Cheng, E. S.; Cross, N. J. G.; Feldman, P. D.; Golimowski, D. A.; Gronwall, C.; Infante, L.; Kimble, R. A.; Krist, J. E.; Lesser, M. P.; Martel, A. R.; Menanteau, F.; Miley, G. K.; Postman, M.; Sirianni, M.; Sparks, W. B.; Tran, H. D.; Tsvetanov, Z. I.; White, R. L.; Zheng, W.

    2003-10-01

    preferred value and suggests a star formation rate of 0.0090+/-0.0031 Msolar yr-1 Mpc-3 to zAB~27, or ~0.036+/-0.012 Msolar yr-1 Mpc-3 by extrapolating the luminosity function to the faint limit, assuming α=-1.6. Third, we follow a very similar procedure, except that we assume no incompleteness, and find a rest-frame continuum luminosity that is ~2-3 times lower than our other two determinations. This final estimate is to be taken as a lower limit and is important if there are modest changes in the colors or surface brightnesses from z~5 to z~6 (the other estimates assume no large changes in the intrinsic selectability of objects). We note that all three estimates are well within the canonical range of luminosity densities necessary for reionization of the universe at this epoch by star-forming galaxies. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 7817, 9290, 9301, and 9583. Based on observations collected at the European Southern Observatory, Paranal, Chile (LP166.A-0701).

  4. Gamma camera

    International Nuclear Information System (INIS)

    Berninger, W.H.

    1975-01-01

    The light pulse output of a scintillator, on which incident collimated gamma rays impinge, is detected by an array of photoelectric tubes each having a convexly curved photocathode disposed in close proximity to the scintillator. Electronic circuitry connected to outputs of the phototubes develops the scintillation event position coordinate electrical signals with good linearity and with substantial independence of the spacing between the scintillator and photocathodes so that the phototubes can be positioned as close to the scintillator as is possible to obtain less distortion in the field of view and improved spatial resolution as compared to conventional planar photocathode gamma cameras

  5. Radioisotope camera

    International Nuclear Information System (INIS)

    Tausch, L.M.; Kump, R.J.

    1978-01-01

    The electronic ciruit corrects distortions caused by the distance between the individual photomultiplier tubes of the multiple radioisotope camera on one hand and between the tube configuration and the scintillator plate on the other. For this purpose the transmission characteristics of the nonlinear circuits are altered as a function of the energy of the incident radiation. By this means the threshold values between lower and higher amplification are adjusted to the energy level of each scintillation. The correcting circuit may be used for any number of isotopes to be measured. (DG) [de

  6. 100ps UV/x-ray framing camera

    International Nuclear Information System (INIS)

    Eagles, R.T.; Freeman, N.J.; Allison, J.M.; Sibbett, W.; Sleat, W.E.; Walker, D.R.

    1988-01-01

    The requirement for a sensitive two-dimensional imaging diagnostic with picosecond time resolution, particularly in the study of laser-produced plasmas, has previously been discussed. A temporal sequence of framed images would provide useful supplementary information to that provided by time resolved streak images across a spectral region of interest from visible to x-ray. To fulfill this requirement the Picoframe camera system has been developed. Results pertaining to the operation of a camera having S20 photocathode sensitivity are reviewed and the characteristics of an UV/x-ray sensitive version of the Picoframe system are presented

  7. MR imaging of medullary streaks in osteosclerosis: a case report

    International Nuclear Information System (INIS)

    Lee, Hak Soo; Joo, Kyung Bin; Park, Tae Soo; Song, Ho Taek; Kim, Yong Soo; Park, Dong Woo; Park, Choong Ki

    2000-01-01

    We present a case of medullary sclerosis of the appendicular skeleton in a patient with chronic renal insufficiency for whom MR imaging findings were characteristic. T1- and T2-weighted MR images showed multiple vertical lines (medullary streaks) of low signal intensity in the metaphyses and diaphyses of the distal femur and proximal tibia

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

    African Journals Online (AJOL)

    Cassava brown streak disease effects on leaf metabolites and pigment accumulation. ... Total reducing sugar and starch content also dropped significantly (-30 and -60%, respectively), much as NASE 14 maintained a relatively higher amount of carbohydrates. Leaf protein levels were significantly reduced at a rate of 0.07 ...

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

    Indian Academy of Sciences (India)

    Supplementary figure 6. 2DE gel images ... Number of acidic streaks. Fedyunin et al. 2012. 4.02. 6. Zuo et al. 2000. 2.54. 9. Valenete et ... CE, 3rd 2009 Proteasomal protein degradation in ... Nandakumar MP, Shen J, Raman B and Marten MR.

  10. Laparoscopic Removal of Streak Gonads in Turner Syndrome.

    Science.gov (United States)

    Mandelberger, Adrienne; Mathews, Shyama; Andikyan, Vaagn; Chuang, Linus

    To demonstrate the skills necessary for complete resection of bilateral streak gonads in Turner syndrome. Video case presentation with narration highlighting the key techniques used. The video was deemed exempt from formal review by our institutional review board. Turner syndrome is a form of gonadal dysgenesis that affects 1 in 2500 live births. Patients often have streak gonads and may present with primary amenorrhea or premature ovarian failure. Patients with a mosaic karyotype that includes a Y chromosome are at increased risk for gonadoblastoma and subsequent transformation into malignancy. Gonadectomy is recommended for these patients, typically at adolescence. Streak gonads can be difficult to identify, and tissue margins are often in close proximity to critical retroperitoneal structures. Resection can be technically challenging and requires a thorough understanding of retroperitoneal anatomy and precise dissection techniques to ensure complete removal. Laparoscopic approach to bilateral salpingo-oophorectomy of streak gonads. Retroperitoneal dissection and ureterolysis are performed, with the aid of the Ethicon Harmonic Ace, to ensure complete gonadectomy. Careful and complete resection of gonadal tissue in the hands of a skilled laparoscopic surgeon is key for effective cancer risk reduction surgery in Turner syndrome mosaics. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

  11. Significance and transmission of maize streak virus disease in Africa ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Dec 29, 2008 ... soil nutrients, altitude and temperature on the biology of maize streak virus (MSV) / vector populations is discussed. ... status of maize host plants and its effects on population dynamics of Cicadulina mbila Naudé. (Homoptera: ..... time necessary for the leafhopper to reach the mesophyll of the leaf and ingest ...

  12. video114_0402c -- Point coverage of sediment observations from video collected during 2005 R/V Tatoosh camera sled survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A custom built camera sled outfitted with video equipment (and other devices) was deployed from the NOAA research vesselTatoosh during August 2005. Video data from...

  13. vid116_0501n -- Point coverage of sediment observations from video collected during 2005 R/V Tatoosh camera sled survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A custom built camera sled outfitted with video equipment (and other devices) was deployed from the NOAA research vessel Tatoosh during August 2005. Video data from...

  14. video115_0403 -- Point coverage of sediment observations from video collected during 2005 R/V Tatoosh camera sled survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A custom built camera sled outfitted with video equipment (and other devices) was deployed from the NOAA research vessel Tatoosh during August 2005. Video data from...

  15. vid116_0501s -- Point coverage of sediment observations from video collected during 2005 R/V Tatoosh camera sled survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A custom built camera sled outfitted with video equipment (and other devices) was deployed from the NOAA research vessel Tatoosh during August 2005. Video data from...

  16. vid116_0501c -- Point coverage of sediment observations from video collected during 2005 R/V Tatoosh camera sled survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A custom built camera sled outfitted with video equipment (and other devices) was deployed from the NOAA research vessel Tatoosh during August 2005. Video data from...

  17. video114_0402b -- Point coverage of sediment observations from video collected during 2005 R/V Tatoosh camera sled survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A custom built camera sled outfitted with video equipment (and other devices) was deployed from the NOAA research vessel Tatoosh during August 2005. Video data from...

  18. vid116_0501d -- Point coverage of sediment observations from video collected during 2005 R/V Tatoosh camera sled survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A custom built camera sled outfitted with video equipment (and other devices) was deployed from the NOAA research vesselTatoosh during August 2005. Video data from...

  19. Streaked x-ray spectrometer having a discrete selection of Bragg geometries for Omega

    Energy Technology Data Exchange (ETDEWEB)

    Millecchia, M.; Regan, S. P.; Bahr, R. E.; Romanofsky, M.; Sorce, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2012-10-15

    The streaked x-ray spectrometer (SXS) is used with streak cameras [D. H. Kalantar, P. M. Bell, R. L. Costa, B. A. Hammel, O. L. Landen, T. J. Orzechowski, J. D. Hares, and A. K. L. Dymoke-Bradshaw, in 22nd International Congress on High-Speed Photography and Photonics, edited by D. L. Paisley and A. M. Frank (SPIE, Bellingham, WA, 1997), Vol. 2869, p. 680] positioned with a ten-inch manipulator on OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] and OMEGA EP [L. J. Waxer et al., Presented at CLEO/QELS 2008, San Jose, CA, 4-9 May 2008 (Paper JThB1)] for time-resolved, x-ray spectroscopy of laser-produced plasmas in the 1.4- to 20-keV photon-energy range. These experiments require measuring a portion of this photon-energy range to monitor a particular emission or absorption feature of interest. The SXS relies on a pinned mechanical reference system to create a discrete set of Bragg reflection geometries for a variety of crystals. A wide selection of spectral windows is achieved accurately and efficiently using this technique. It replaces the previous spectrometer designs that had a continuous Bragg angle adjustment and required a tedious alignment calibration procedure. The number of spectral windows needed for the SXS was determined by studying the spectral ranges selected by OMEGA users over the last decade. These selections are easily configured in the SXS using one of the 25 discrete Bragg reflection geometries and one of the six types of Bragg crystals, including two curved crystals.

  20. Gamma camera

    International Nuclear Information System (INIS)

    Conrad, B.; Heinzelmann, K.G.

    1975-01-01

    A gamma camera is described which obviates the distortion of locating signals generally caused by the varied light conductive capacities of the light conductors in that the flow of light through each light conductor may be varied by means of a shutter. A balancing of the flow of light through each of the individual light conductors, in effect, collective light conductors may be balanced on the basis of their light conductive capacities or properties, so as to preclude a distortion of the locating signals caused by the varied light conductive properties of the light conductors. Each light conductor has associated therewith two, relative to each other, independently adjustable shutters, of which one forms a closure member and the other an adjusting shutter. In this embodiment of the invention it is thus possible to block all of the light conductors leading to a photoelectric transducer, with the exception of those light conductors which are to be balanced. The balancing of the individual light conductors may then be obtained on the basis of the output signals of the photoelectric transducer. (auth)

  1. Scintillation camera

    International Nuclear Information System (INIS)

    Zioni, J.; Klein, Y.; Inbar, D.

    1975-01-01

    The scintillation camera is to make pictures of the density distribution of radiation fields created by the injection or administration radioactive medicaments into the body of the patient. It contains a scintillation crystal, several photomultipliers and computer circuits to obtain an analytical function at the exits of the photomultiplier which is dependent on the position of the scintillations at the time in the crystal. The scintillation crystal is flat and spatially corresponds to the production site of radiation. The photomultipliers form a pattern whose basic form consists of at least three photomultipliers. They are assigned to at least two crossing parallel series groups where a vertical running reference axis in the crystal plane belongs to each series group. The computer circuits are each assigned to a reference axis. Each series of a series group assigned to one of the reference axes in the computer circuit has an adder to produce a scintillation dependent series signal. Furthermore, the projection of the scintillation on this reference axis is calculated. A series signal is used for this which originates from a series chosen from two neighbouring photomultiplier series of this group. The scintillation must have appeared between these chosen series. They are termed as basic series. The photomultiplier can be arranged hexagonally or rectangularly. (GG/LH) [de

  2. Development of a visible framing camera diagnostic for the study of current initiation in z-pinch plasmas

    International Nuclear Information System (INIS)

    Muron, D.J.; Hurst, M.J.; Derzon, M.S.

    1996-01-01

    The authors assembled and tested a visible framing camera system to take 5 ns FWHM images of the early time emission from a z-pinch plasma. This diagnostic was used in conjunction with a visible streak camera allowing early time emissions measurements to diagnose current initiation. Individual frames from gated image intensifiers were proximity coupled to charge injection device (CID) cameras and read out at video rate and 8-bit resolution. A mirror was used to view the pinch from a 90-degree angle. The authors observed the destruction of the mirror surface, due to the high surface heating, and the subsequent reduction in signal reflected from the mirror. Images were obtained that showed early time ejecta and a nonuniform emission from the target. This initial test of the equipment highlighted problems with this measurement. They observed non-uniformities in early time emission. This is believed to be due to either spatially varying current density or heating of the foam. Images were obtained that showed early time ejecta from the target. The results and suggestions for improvement are discussed in the text

  3. A NEW CEPHEID DISTANCE TO THE GIANT SPIRAL M101 BASED ON IMAGE SUBTRACTION OF HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS OBSERVATIONS

    International Nuclear Information System (INIS)

    Shappee, Benjamin J.; Stanek, K. Z.

    2011-01-01

    We accurately determine a new Cepheid distance to M101 (NGC 5457) using archival Hubble Space Telescope (HST)/Advanced Camera for Surveys V and I time series photometry of two fields within the galaxy. We make a slight modification to the ISIS image subtraction package to obtain optimal differential light curves from HST data. We discovered 827 Cepheids with periods between 3 and 80 days, the largest extragalactic sample of Cepheids observed with HST by a factor of two. With this large Cepheid sample, we find that the relative distance of M101 from the Large Magellanic Cloud is Δμ LMC = 10.63 ± 0.04 (random) ± 0.06 (systematic) mag. If we use the geometrically determined maser distance to NGC 4258 as our distance anchor, the distance modulus of M101 is μ 0 = 29.04 ± 0.05 (random) ± 0.18 (systematic) mag or D = 6.4 ± 0.2 (random) ± 0.5 (systematic) Mpc. The uncertainty is dominated by the maser distance estimate (±0.15 mag), which should improve over the next few years. We determine a steep metallicity dependence, γ, for our Cepheid sample through two methods, yielding γ = -0.80 ± 0.21 (random) ± 0.06 (systematic) mag dex -1 and γ = -0.72 +0.22 -0.25 (random) ± 0.06 (systematic) mag dex -1 . We see marginal evidence for variations in the Wesenheit period-luminosity relation slope as a function of deprojected galactocentric radius. We also use the tip of the red giant branch method to independently determine the distance modulus to M101 of μ 0 = 29.05 ± 0.06 (random) ± 0.12 (systematic) mag.

  4. Observation of the lymph flow in the lower extremities of edematous patients with noninvasive methods. RI-lymphography with a computer onlined gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Isao; Hirota, Akio; Watanabe, Sumio (Toho Univ., Tokyo (Japan). School of Medicine)

    1983-09-01

    An RI-lymphography with a computer onlined gamma camera was used for observing the lymph flow of edematous patients without any invasive procedures and for estimating the active movement of lymph vessels. Subjects were composed of 8 normal volunteers (group 1), 41 non-edematous patients (group 2) and 26 edematous patients (group 3). Four mCi of Tc-99m-HSA in a volume of 0.1 ml was injected subcutaneously in the pretibial region of the lower extremity, and immediately after the injection scintigram was recorded on the thigh every 5 sec. for 30 min. Results: 1) Normal volunteers; Time-activity curves showed a gradual increase in RI activity in relation to time without remarkable spike-like fluctuations. The maximum count attained was less than 200 cps in all experiments. 2) Non-edematous patients; In 46 out of 57 experiments (80.8%), the similar time-activity curves were observed as those of the normal volunteers. On the other hand, time-activity curves in 11 out of 57 (19.2%) showed a much steeper stepwise-increase simultaneously with remarkable spike-waves. The maximum count was over 200 cps in these cases. 3) Edematous patients; In 12 out of 35 experiments (34.3%), the maximum count was over 200 cps. In these edematous diseases other than lymphedema and hyperthyroidism, time-activity curves showed a rapid stepwise increase with a lot of spikes, and the maximum count was over 500 cps in 6 experiments. In 23 out of 35 (65.7%), the maximum count was less than 200 cps. In these cases, edema was attributable to secondary lymphedema, hypothyroidism, aging and so on. 4) Relationship between edema and lymph flow: When subjects were divided into 3 groups (non-edema, mild and severe edema), the maximum count 200 cps was observed in 16.7% in non-edema group, 45.8% in mild and 9.1% in severe edema group.

  5. In situ camera observations reveal major role of zooplankton in modulating marine snow formation during an upwelling-induced plankton bloom

    Science.gov (United States)

    Taucher, Jan; Stange, Paul; Algueró-Muñiz, María; Bach, Lennart T.; Nauendorf, Alice; Kolzenburg, Regina; Büdenbender, Jan; Riebesell, Ulf

    2018-05-01

    Particle aggregation and the consequent formation of marine snow alter important properties of biogenic particles (size, sinking rate, degradability), thus playing a key role in controlling the vertical flux of organic matter to the deep ocean. However, there are still large uncertainties about rates and mechanisms of particle aggregation, as well as the role of plankton community structure in modifying biomass transfer from small particles to large fast-sinking aggregates. Here we present data from a high-resolution underwater camera system that we used to observe particle size distributions and formation of marine snow (aggregates >0.5 mm) over the course of a 9-week in situ mesocosm experiment in the Eastern Subtropical North Atlantic. After an oligotrophic phase of almost 4 weeks, addition of nutrient-rich deep water (650 m) initiated the development of a pronounced diatom bloom and the subsequent formation of large marine snow aggregates in all 8 mesocosms. We observed a substantial time lag between the peaks of chlorophyll a and marine snow biovolume of 9-12 days, which is much longer than previously reported and indicates a marked temporal decoupling of phytoplankton growth and marine snow formation during our study. Despite this time lag, our observations revealed substantial transfer of biomass from small particle sizes (single phytoplankton cells and chains) to marine snow aggregates of up to 2.5 mm diameter (ESD), with most of the biovolume being contained in the 0.5-1 mm size range. Notably, the abundance and community composition of mesozooplankton had a substantial influence on the temporal development of particle size spectra and formation of marine snow aggregates: While higher copepod abundances were related to reduced aggregate formation and biomass transfer towards larger particle sizes, the presence of appendicularia and doliolids enhanced formation of large marine snow. Furthermore, we combined in situ particle size distributions with

  6. Electro-optical design of a long slit streak tube

    Science.gov (United States)

    Tian, Liping; Tian, Jinshou; Wen, Wenlong; Chen, Ping; Wang, Xing; Hui, Dandan; Wang, Junfeng

    2017-11-01

    A small size and long slit streak tube with high spatial resolution was designed and optimized. Curved photocathode and screen were adopted to increase the photocathode working area and spatial resolution. High physical temporal resolution obtained by using a slit accelerating electrode. Deflection sensitivity of the streak tube was improved by adopting two-folded deflection plates. The simulations indicate that the photocathode effective working area can reach 30mm × 5mm. The static spatial resolution is higher than 40lp/mm and 12lp/mm along scanning and slit directions respectively while the physical temporal resolution is higher than 60ps. The magnification is 0.75 and 0.77 in scanning and slit directions. And also, the deflection sensitivity is as high as 37mm/kV. The external dimension of the streak tube are only ∅74mm×231mm. Thus, it can be applied to laser imaging radar system for large field of view and high range precision detection.

  7. NSTX Tangential Divertor Camera

    International Nuclear Information System (INIS)

    Roquemore, A.L.; Ted Biewer; Johnson, D.; Zweben, S.J.; Nobuhiro Nishino; Soukhanovskii, V.A.

    2004-01-01

    Strong magnetic field shear around the divertor x-point is numerically predicted to lead to strong spatial asymmetries in turbulence driven particle fluxes. To visualize the turbulence and associated impurity line emission near the lower x-point region, a new tangential observation port has been recently installed on NSTX. A reentrant sapphire window with a moveable in-vessel mirror images the divertor region from the center stack out to R 80 cm and views the x-point for most plasma configurations. A coherent fiber optic bundle transmits the image through a remotely selected filter to a fast camera, for example a 40500 frames/sec Photron CCD camera. A gas puffer located in the lower inboard divertor will localize the turbulence in the region near the x-point. Edge fluid and turbulent codes UEDGE and BOUT will be used to interpret impurity and deuterium emission fluctuation measurements in the divertor

  8. THE LUMINOSITY, MASS, AND AGE DISTRIBUTIONS OF COMPACT STAR CLUSTERS IN M83 BASED ON HUBBLE SPACE TELESCOPE/WIDE FIELD CAMERA 3 OBSERVATIONS

    International Nuclear Information System (INIS)

    Chandar, Rupali; Whitmore, Bradley C.; Mutchler, Max; Bond, Howard; Kim, Hwihyun; Kaleida, Catherine; Calzetti, Daniela; Saha, Abhijit; O'Connell, Robert; Balick, Bruce; Carollo, Marcella; Disney, Michael; Dopita, Michael A.; Frogel, Jay A.; Hall, Donald; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick; Paresce, Francesco; Silk, Joe

    2010-01-01

    The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a grand-design spiral, particularly in the near-ultraviolet, and allow us to better differentiate compact star clusters from individual stars and to measure the luminosities of even faint clusters in the U band. We find that the luminosity function (LF) for clusters outside of the very crowded starburst nucleus can be approximated by a power law, dN/dL ∝ L α , with α = -2.04 ± 0.08, down to M V ∼ -5.5. We test the sensitivity of the LF to different selection techniques, filters, binning, and aperture correction determinations, and find that none of these contribute significantly to uncertainties in α. We estimate ages and masses for the clusters by comparing their measured UBVI, Hα colors with predictions from single stellar population models. The age distribution of the clusters can be approximated by a power law, dN/dτ ∝ τ γ , with γ = -0.9 ± 0.2, for M ∼> few x 10 3 M sun and τ ∼ 8 yr. This indicates that clusters are disrupted quickly, with ∼80%-90% disrupted each decade in age over this time. The mass function of clusters over the same M-τ range is a power law, dN/dM ∝ M β , with β = -1.94 ± 0.16, and does not have bends or show curvature at either high or low masses. Therefore, we do not find evidence for a physical upper mass limit, M C , or for the earlier disruption of lower mass clusters when compared with higher mass clusters, i.e., mass-dependent disruption. We briefly discuss these implications for the formation and disruption of the clusters.

  9. Proposal of balloon and satellite observations of MeV gammas using Electron Tracking Compton Camera for reaching a high sensitivity of 1 mCrab

    Science.gov (United States)

    Takada, Atsushi; Tanimori, Toru

    2016-04-01

    ETCC with a gas Time Projection Chamber (TPC) and pixel GSO scintillators, by measuring electron tracks precisely, provides both a strong background rejection by dE/dx of the track and well-defined 2-dimensional Point Spread Function (PDF) with better than several degrees by adding the arc direction of incident gammas (SPD: Scatter Plane Deviation) with the ARM (angular Resolution Measure) direction measured in standard Compton Camera (CC). In 2006 its background rejection was revealed by SMILE-I balloon experiment with 10cm-cubic ETCC using the dE/dx of tracks. In 2013, 30cm-cube-ETCC has been developed to catch gammas from Crab in next SMILE-II balloon with >5sigma detection for 4 hrs. Now its sensitivity has been improved to 10sigma by attaining the angular resolution of the track (SPD angle) to that determined by multiple scattering of the gas. Thus, we show the ability of ETCC to give a better significance by a factor of 10 than that of standard CCs having same detection area by electron tracking?and we have found that SPD is an essential to define the PSF of Compton imaging quantitatively. Such a well-defined PSF is, for the first time, able to provide reliable sensitivity in Compton imaging without assuming the use of optimization algorithm. These studies uncover the uncertainties of CCs from both points of view of the intense background and the difficulty of the definition of the PSF, and overcome the above problems. Based on this technology, SMILE-II with 3atm CF4 gas is expected to provide a 5times better sensitivity than COMPTEL in one month balloon, and 4modules of 50cm-cube ETCCs would exceed over 10^-12 erg/cm^2s^1 (1mCrab) in satellite. Here we summarize the performance of the ETCC and new astrophysics opened in near future by high sensitive observation of MeV gamma-rays.

  10. 100-ps framing-camera tube

    International Nuclear Information System (INIS)

    Kalibjian, R.

    1978-01-01

    The optoelectronic framing-camera tube described is capable of recording two-dimensional image frames with high spatial resolution in the <100-ps range. Framing is performed by streaking a two-dimensional electron image across narrow slits. The resulting dissected electron line images from the slits are restored into framed images by a restorer deflector operating synchronously with the dissector deflector. The number of framed images on the tube's viewing screen equals the number of dissecting slits in the tube. Performance has been demonstrated in a prototype tube by recording 135-ps-duration framed images of 2.5-mm patterns at the cathode. The limitation in the framing speed is in the external drivers for the deflectors and not in the tube design characteristics. Faster frame speeds in the <100-ps range can be obtained by use of faster deflection drivers

  11. Scientific Objectives of Small Carry-on Impactor (SCI) and Deployable Camera 3 Digital (DCAM3-D): Observation of an Ejecta Curtain and a Crater Formed on the Surface of Ryugu by an Artificial High-Velocity Impact

    Science.gov (United States)

    Arakawa, M.; Wada, K.; Saiki, T.; Kadono, T.; Takagi, Y.; Shirai, K.; Okamoto, C.; Yano, H.; Hayakawa, M.; Nakazawa, S.; Hirata, N.; Kobayashi, M.; Michel, P.; Jutzi, M.; Imamura, H.; Ogawa, K.; Sakatani, N.; Iijima, Y.; Honda, R.; Ishibashi, K.; Hayakawa, H.; Sawada, H.

    2017-07-01

    The Small Carry-on Impactor (SCI) equipped on Hayabusa2 was developed to produce an artificial impact crater on the primitive Near-Earth Asteroid (NEA) 162173 Ryugu (Ryugu) in order to explore the asteroid subsurface material unaffected by space weathering and thermal alteration by solar radiation. An exposed fresh surface by the impactor and/or the ejecta deposit excavated from the crater will be observed by remote sensing instruments, and a subsurface fresh sample of the asteroid will be collected there. The SCI impact experiment will be observed by a Deployable CAMera 3-D (DCAM3-D) at a distance of ˜1 km from the impact point, and the time evolution of the ejecta curtain will be observed by this camera to confirm the impact point on the asteroid surface. As a result of the observation of the ejecta curtain by DCAM3-D and the crater morphology by onboard cameras, the subsurface structure and the physical properties of the constituting materials will be derived from crater scaling laws. Moreover, the SCI experiment on Ryugu gives us a precious opportunity to clarify effects of microgravity on the cratering process and to validate numerical simulations and models of the cratering process.

  12. MUSIC - Multifunctional stereo imaging camera system for wide angle and high resolution stereo and color observations on the Mars-94 mission

    Science.gov (United States)

    Oertel, D.; Jahn, H.; Sandau, R.; Walter, I.; Driescher, H.

    1990-10-01

    Objectives of the multifunctional stereo imaging camera (MUSIC) system to be deployed on the Soviet Mars-94 mission are outlined. A high-resolution stereo camera (HRSC) and wide-angle opto-electronic stereo scanner (WAOSS) are combined in terms of hardware, software, technology aspects, and solutions. Both HRSC and WAOSS are push-button instruments containing a single optical system and focal plates with several parallel CCD line sensors. Emphasis is placed on the MUSIC system's stereo capability, its design, mass memory, and data compression. A 1-Gbit memory is divided into two parts: 80 percent for HRSC and 20 percent for WAOSS, while the selected on-line compression strategy is based on macropixel coding and real-time transform coding.

  13. Transition due to streamwise streaks in a supersonic flat plate boundary layer

    Science.gov (United States)

    Paredes, Pedro; Choudhari, Meelan M.; Li, Fei

    2016-12-01

    Transition induced by stationary streaks undergoing transient growth in a supersonic flat plate boundary layer flow is studied using numerical computations. While the possibility of strong transient growth of small-amplitude stationary perturbations in supersonic boundary layer flows has been demonstrated in previous works, its relation to laminar-turbulent transition cannot be established within the framework of linear disturbances. Therefore, this paper investigates the nonlinear evolution of initially linear optimal disturbances that evolve into finite amplitude streaks in the downstream region, and then studies the modal instability of those streaks as a likely cause for the onset of bypass transition. The nonmodal evolution of linearly optimal stationary perturbations in a supersonic, Mach 3 flat plate boundary layer is computed via the nonlinear plane-marching parabolized stability equations (PSE) for stationary perturbations, or equivalently, the perturbation form of parabolized Navier-Stokes equations. To assess the effect of the nonlinear finite-amplitude streaks on transition, the linear form of plane-marching PSE is used to investigate the instability of the boundary layer flow modified by the spanwise periodic streaks. The onset of transition is estimated using an N -factor criterion based on modal amplification of the secondary instabilities of the streaks. In the absence of transient growth disturbances, first mode instabilities in a Mach 3, zero pressure gradient boundary layer reach N =10 at Rex≈107 . However, secondary instability modes of the stationary streaks undergoing transient growth are able to achieve the same N -factor at Rex<2 ×106 when the initial streak amplitude is sufficiently large. In contrast to the streak instabilities in incompressible flows, subharmonic instability modes with twice the fundamental spanwise wavelength of the streaks are found to have higher amplification ratios than the streak instabilities at fundamental

  14. Observation of X-ray shadings in synchrotron radiation-total reflection X-ray fluorescence using a color X-ray camera

    Energy Technology Data Exchange (ETDEWEB)

    Fittschen, Ursula Elisabeth Adriane, E-mail: ursula.fittschen@chemie.uni-hamburg.de [Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Menzel, Magnus [Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Scharf, Oliver [IfG Institute for Scientific Instruments GmbH, Berlin (Germany); Radtke, Martin; Reinholz, Uwe; Buzanich, Günther [BAM Federal Institute of Materials Research and Testing, Berlin (Germany); Lopez, Velma M.; McIntosh, Kathryn [Los Alamos National Laboratory, Los Alamos, NM (United States); Streli, Christina [Atominstitut, TU Wien, Vienna (Austria); Havrilla, George Joseph [Los Alamos National Laboratory, Los Alamos, NM (United States)

    2014-09-01

    Absorption effects and the impact of specimen shape on TXRF analysis has been discussed intensively. Model calculations indicated that ring shaped specimens should give better results in terms of higher counts per mass signals than filled rectangle or circle shaped specimens. One major reason for the difference in signal is shading effects. Full field micro-XRF with a color X-ray camera (CXC) was used to investigate shading, which occurs when working with small angles of excitation as in TXRF. The device allows monitoring the illuminated parts of the sample and the shaded parts at the same time. It is expected that sample material hit first by the primary beam shade material behind it. Using the CXC shading could be directly visualized for the high concentration specimens. In order to compare the experimental results with calculation of the shading effect the generation of controlled specimens is crucial. This was achieved by “drop on demand” technology. It allows generating uniform, microscopic deposits of elements. The experimentally measured shadings match well with those expected from calculation. - Highlights: • Use of a color X-ray camera and drop on demand printing to diagnose X-ray shading • Specimens were obtained uniform and well-defined in shape and concentration by printing. • Direct visualization and determination of shading in such specimens using the camera.

  15. Observation of X-ray shadings in synchrotron radiation-total reflection X-ray fluorescence using a color X-ray camera

    International Nuclear Information System (INIS)

    Fittschen, Ursula Elisabeth Adriane; Menzel, Magnus; Scharf, Oliver; Radtke, Martin; Reinholz, Uwe; Buzanich, Günther; Lopez, Velma M.; McIntosh, Kathryn; Streli, Christina; Havrilla, George Joseph

    2014-01-01

    Absorption effects and the impact of specimen shape on TXRF analysis has been discussed intensively. Model calculations indicated that ring shaped specimens should give better results in terms of higher counts per mass signals than filled rectangle or circle shaped specimens. One major reason for the difference in signal is shading effects. Full field micro-XRF with a color X-ray camera (CXC) was used to investigate shading, which occurs when working with small angles of excitation as in TXRF. The device allows monitoring the illuminated parts of the sample and the shaded parts at the same time. It is expected that sample material hit first by the primary beam shade material behind it. Using the CXC shading could be directly visualized for the high concentration specimens. In order to compare the experimental results with calculation of the shading effect the generation of controlled specimens is crucial. This was achieved by “drop on demand” technology. It allows generating uniform, microscopic deposits of elements. The experimentally measured shadings match well with those expected from calculation. - Highlights: • Use of a color X-ray camera and drop on demand printing to diagnose X-ray shading • Specimens were obtained uniform and well-defined in shape and concentration by printing. • Direct visualization and determination of shading in such specimens using the camera

  16. Development of miniaturized proximity focused streak tubes for visible light and x-ray applications. Final report and progress, April-September 1977

    International Nuclear Information System (INIS)

    Cuny, J.J.; Knight, A.J.

    1978-02-01

    Research performed to develop miniaturized proximity focused streak camera tubes (PFST) for application in the visible and the x-ray modes of operation is described. The objective of this research was to provide an engineering design and to fabricate a visible and an x-ray prototype tube to be provided to LASL for test and evaluation. Materials selection and fabrication procedures, particularly the joining of beryllium to a suitable support ring for use as the x-ray window, are described in detail. The visible and x-ray PFST's were successfully fabricated

  17. Streaked spectrometry using multilayer x-ray-interference mirrors to investigate energy transport in laser-plasma applications

    International Nuclear Information System (INIS)

    Stradling, G.L.; Barbee, T.W. Jr.; Henke, B.L.; Campbell, E.M.; Mead, W.C.

    1981-08-01

    Transport of energy in laser-produced plasmas is scrutinized by devising spectrally and temporally identifiable characteristics in the x-ray emission history which identify the heat-front position at various times in the heating process. Measurements of the relative turn-on times of these characteristics show the rate of energy transport between various points. These measurements can in turn constrain models of energy transport phenomena. We are time-resolving spectrally distinguishable subkilovolt x-ray emissions from different layers of a disk target to examine the transport rate of energy into the target. A similar technique is used to measure the lateral expansion rate of the plasma spot. A soft x-ray streak camera with 15-psec temporal resolution is used to make the temporal measurements. Spectral discrimination of the incident signal is provided by multilayer x-ray interference mirrors

  18. Intellectual streaking: The value of teachers exposing minds (and hearts).

    Science.gov (United States)

    Bearman, Margaret; Molloy, Elizabeth

    2017-12-01

    As teachers we often ask learners to be vulnerable and yet present ourselves as high status, knowledgeable experts, often with pre-prepared scripts. This paper investigates the metaphoric notion of "intellectual streaking" - the nimble exposure of a teacher's thought processes, dilemmas, or failures - as a way of modeling both reflection-in-action and resilience. While there is a tension between credibility and vulnerability, both of which are necessary for trust, we argue that taking a few risks and revealing deficits in knowledge or performance can be illuminating and valuable for all parties.

  19. Angioid streaks in a case of Camurati–Engelmann disease

    Directory of Open Access Journals (Sweden)

    Betül Tugcu

    2017-01-01

    Full Text Available Camurati–Engelmann disease (CED is a rare autosomal dominant disease with various phenotypic expressions. The hallmark of the disease is bilateral symmetric diaphyseal hyperostosis of the long bones with progressive involvement of the metaphysis. Ocular manifestations occur rarely and mainly result from bony overgrowth of the orbit and optic canal stenosis. We report a case of CED showing angioid streaks (ASs in both fundi with no macular involvement and discuss the possible theories of the pathogenesis of AS in this disease.

  20. Making Ceramic Cameras

    Science.gov (United States)

    Squibb, Matt

    2009-01-01

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

  1. Relationships between early spring wheat streak mosaic severity levels and grain yield: Implications for management decisions

    Science.gov (United States)

    Wheat streak mosaic (WSM) caused by Wheat streak mosaic virus, which is transmitted by the wheat curl mite (Aceria tosichella), is a major yield-limiting disease in the Texas High Plains. In addition to its impact on grain production, the disease reduces water-use efficiency by affecting root develo...

  2. Bilateral choroidal neovascularization response to unilateral intravitreal Ranibizumab injection in a patient with angioid streaks

    Directory of Open Access Journals (Sweden)

    Otacílio de Oliveira Maia Júnior

    2013-08-01

    Full Text Available Report of a 48 year-old male with bilateral decrease in vision due to choroidal neovascularization secondary to angioid streaks. Best corrected visual acuity was 20/80 in the right eye and counting fingers at 2 meters on the left eye. Patient underwent intravitreal injection of Ranibizumab (Lucentis in the eye with worse visual acuity. Fifteen days after treatment patient reported better visual acuity on the fellow eye, which was measured to be 20/25. Treatment result was evaluated with visual acuity and optical coherence tomography. The effect of ranibizumab was observed in the treated eye, but the fellow eye had complete resolution of the choroidal neovascularization complex. This result may be a response to systemic absorption of the medication.

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

    Science.gov (United States)

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

    2013-10-01

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

  4. Adapting Virtual Camera Behaviour

    DEFF Research Database (Denmark)

    Burelli, Paolo

    2013-01-01

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

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

    OpenAIRE

    Heng-mu ZHANG; Hua-di WANG; Jian YANG; Michael J ADAMS; Jian-ping CHEN

    2013-01-01

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

  6. Major QTL Conferring Resistance to Rice Bacterial Leaf Streak

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Bacterial leaf streak (BLS) is one of the important limiting factors to rice production in southern China and other tropical and sub-tropical areas in Asia. Resistance to BLS was found to be a quantitative trait and no major resistant gene was located in rice until date. In the present study, a new major quantitative trait locus (QTL) conferring resistance to BLS was identified from a highly resistant variety Dular by the employment of Dular/Balilla (DB) and Dular/IR24 (DI) segregation populations and was designated qBLSR-11-1. This QTL was located between the simple sequence repeat (SSR) markers RM120 and RM441 on chromosome 11 and could account for 18.1-21.7% and 36.3% of the variance in DB and DI populations, respectively. The genetic pattern of rice resistance to BLS was discussed.

  7. Initial Observations of Micropulse Elongation of Electron Beams in a SCRF Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H. [Fermilab; Thurman-Keup, R. [Fermilab; Edstrom Jr., D. [Fermilab; Ruan, J. [Fermilab; Santucci, J. [Fermilab

    2016-10-09

    Commissioning at the SCRF accelerator at the Fermilab Accelerator Science and Technology (FAST) Facility has included the implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The team has initially used a Hamamatsu C5680 synchroscan streak camera to assess the effects of space charge on the electron beam bunch lengths. An Al-coated Si screen was used to generate optical transition radiation (OTR) resulting from the beam’s interaction with the screen. The chicane bypass beamline allowed the measurements of the bunch length without the compression stage at the downstream beamline location using OTR and the streak camera. We have observed electron beam bunch lengths from 5 to 16 ps (sigma) for micropulse charges of 60 pC to 800 pC, respectively. We also report a compressed sub-ps micropulse case.

  8. The fly's eye camera system

    Science.gov (United States)

    Mészáros, L.; Pál, A.; Csépány, G.; Jaskó, A.; Vida, K.; Oláh, K.; Mezö, G.

    2014-12-01

    We introduce the Fly's Eye Camera System, an all-sky monitoring device intended to perform time domain astronomy. This camera system design will provide complementary data sets for other synoptic sky surveys such as LSST or Pan-STARRS. The effective field of view is obtained by 19 cameras arranged in a spherical mosaic form. These individual cameras of the device stand on a hexapod mount that is fully capable of achieving sidereal tracking for the subsequent exposures. This platform has many advantages. First of all it requires only one type of moving component and does not include unique parts. Hence this design not only eliminates problems implied by unique elements, but the redundancy of the hexapod allows smooth operations even if one or two of the legs are stuck. In addition, it can calibrate itself by observed stars independently from both the geographical location (including northen and southern hemisphere) and the polar alignment of the full mount. All mechanical elements and electronics are designed within the confines of our institute Konkoly Observatory. Currently, our instrument is in testing phase with an operating hexapod and reduced number of cameras.

  9. Laser scanning camera inspects hazardous area

    International Nuclear Information System (INIS)

    Fryatt, A.; Miprode, C.

    1985-01-01

    Main operational characteristics of a new laser scanning camera are presented. The camera is intended primarily for low level high resolution viewing inside nuclear reactors. It uses a He-Ne laser beam raster; by detecting the reflected light by means of a phomultiplier, the subject under observation can be reconstructed in an electronic video store and reviewed on a conventional monitor screen

  10. Near Real-Time Ground-to-Ground Infrared Remote-Sensing Combination and Inexpensive Visible Camera Observations Applied to Tomographic Stack Emission Measurements

    Directory of Open Access Journals (Sweden)

    Philippe de Donato

    2018-04-01

    Full Text Available Evaluation of the environmental impact of gas plumes from stack emissions at the local level requires precise knowledge of the spatial development of the cloud, its evolution over time, and quantitative analysis of each gaseous component. With extensive developments, remote-sensing ground-based technologies are becoming increasingly relevant to such an application. The difficulty of determining the exact 3-D thickness of the gas plume in real time has meant that the various gas components are mainly expressed using correlation coefficients of gas occurrences and path concentration (ppm.m. This paper focuses on a synchronous and non-expensive multi-angled approach combining three high-resolution visible cameras (GoPro-Hero3 and a scanning infrared (IR gas system (SIGIS, Bruker. Measurements are performed at a NH3 emissive industrial site (NOVACARB Society, Laneuveville-devant-Nancy, France. Visible data images were processed by a first geometrical reconstruction gOcad® protocol to build a 3-D envelope of the gas plume which allows estimation of the plume’s thickness corresponding to the 2-D infrared grid measurements. NH3 concentration data could thereby be expressed in ppm and have been interpolated using a second gOcad® interpolation algorithm allowing a precise volume visualization of the NH3 distribution in the flue gas steam.

  11. Observation of laser-induced elastic waves in agar skin phantoms using a high-speed camera and a laser-beam-deflection probe.

    Science.gov (United States)

    Laloš, Jernej; Gregorčič, Peter; Jezeršek, Matija

    2018-04-01

    We present an optical study of elastic wave propagation inside skin phantoms consisting of agar gel as induced by an Er:YAG (wavelength of 2.94 μm) laser pulse. A laser-beam-deflection probe is used to measure ultrasonic propagation and a high-speed camera is used to record displacements in ablation-induced elastic transients. These measurements are further analyzed with a custom developed image recognition algorithm utilizing the methods of particle image velocimetry and spline interpolation to determine point trajectories, material displacement and strain during the passing of the transients. The results indicate that the ablation-induced elastic waves propagate with a velocity of 1 m/s and amplitudes of 0.1 mm. Compared to them, the measured velocities of ultrasonic waves are much higher, within the range of 1.42-1.51 km/s, while their amplitudes are three orders of magnitude smaller. This proves that the agar gel may be used as a rudimental skin and soft tissue substitute in biomedical research, since its polymeric structure reproduces adequate soft-solid properties and its transparency for visible light makes it convenient to study with optical instruments. The results presented provide an insight into the distribution of laser-induced elastic transients in soft tissue phantoms, while the experimental approach serves as a foundation for further research of laser-induced mechanical effects deeper in the tissue.

  12. Time-lapse camera observations of gas piston activity at Pu‘u ‘Ō‘ō, Kīlauea volcano, Hawai‘i

    Science.gov (United States)

    Orr, Tim R.; Rea, James

    2012-01-01

    Gas pistoning is a type of eruptive behavior described first at Kīlauea volcano and characterized by the (commonly) cyclic rise and fall of the lava surface within a volcanic vent or lava lake. Though recognized for decades, its cause continues to be debated, and determining why and when it occurs has important implications for understanding vesiculation and outgassing processes at basaltic volcanoes. Here, we describe gas piston activity that occurred at the Pu‘u ‘Ō‘ō cone, in Kīlauea’s east rift zone, during June 2006. Direct, detailed measurements of lava level, made from time-lapse camera images captured at close range, show that the gas pistons during the study period lasted from 2 to 60 min, had volumes ranging from 14 to 104 m3, displayed a slowing rise rate of the lava surface, and had an average gas release duration of 49 s. Our data are inconsistent with gas pistoning models that invoke gas slug rise or a dynamic pressure balance but are compatible with models which appeal to gas accumulation and loss near the top of the lava column, possibly through the generation and collapse of a foam layer.

  13. Earth aeolian wind streaks: Comparison to wind data from model and stations

    Science.gov (United States)

    Cohen-Zada, A. L.; Maman, S.; Blumberg, D. G.

    2017-05-01

    Wind streak is a collective term for a variety of aeolian features that display distinctive albedo surface patterns. Wind streaks have been used to map near-surface winds and to estimate atmospheric circulation patterns on Mars and Venus. However, because wind streaks have been studied mostly on Mars and Venus, much of the knowledge regarding the mechanism and time frame of their formation and their relationship to the atmospheric circulation cannot be verified. This study aims to validate previous studies' results by a comparison of real and modeled wind data with wind streak orientations as measured from remote-sensing images. Orientations of Earth wind streaks were statistically correlated to resultant drift direction (RDD) values calculated from reanalysis and wind data from 621 weather stations. The results showed good agreement between wind streak orientations and reanalysis RDD (r = 0.78). A moderate correlation was found between the wind streak orientations and the weather station data (r = 0.47); a similar trend was revealed on a regional scale when the analysis was performed by continent, with r ranging from 0.641 in North America to 0.922 in Antarctica. At sites where wind streak orientations did not correspond to the RDDs (i.e., a difference of 45°), seasonal and diurnal variations in the wind flow were found to be responsible for deviation from the global pattern. The study thus confirms that Earth wind streaks were formed by the present wind regime and they are indeed indicative of the long-term prevailing wind direction on global and regional scales.

  14. Radiation camera exposure control

    International Nuclear Information System (INIS)

    Martone, R.J.; Yarsawich, M.; Wolczek, W.

    1976-01-01

    A system and method for governing the exposure of an image generated by a radiation camera to an image sensing camera is disclosed. The exposure is terminated in response to the accumulation of a predetermined quantity of radiation, defining a radiation density, occurring in a predetermined area. An index is produced which represents the value of that quantity of radiation whose accumulation causes the exposure termination. The value of the predetermined radiation quantity represented by the index is sensed so that the radiation camera image intensity can be calibrated to compensate for changes in exposure amounts due to desired variations in radiation density of the exposure, to maintain the detectability of the image by the image sensing camera notwithstanding such variations. Provision is also made for calibrating the image intensity in accordance with the sensitivity of the image sensing camera, and for locating the index for maintaining its detectability and causing the proper centering of the radiation camera image

  15. GRACE star camera noise

    Science.gov (United States)

    Harvey, Nate

    2016-08-01

    Extending results from previous work by Bandikova et al. (2012) and Inacio et al. (2015), this paper analyzes Gravity Recovery and Climate Experiment (GRACE) star camera attitude measurement noise by processing inter-camera quaternions from 2003 to 2015. We describe a correction to star camera data, which will eliminate a several-arcsec twice-per-rev error with daily modulation, currently visible in the auto-covariance function of the inter-camera quaternion, from future GRACE Level-1B product releases. We also present evidence supporting the argument that thermal conditions/settings affect long-term inter-camera attitude biases by at least tens-of-arcsecs, and that several-to-tens-of-arcsecs per-rev star camera errors depend largely on field-of-view.

  16. Solid state video cameras

    CERN Document Server

    Cristol, Y

    2013-01-01

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

  17. Stabilization of the hypersonic boundary layer by finite-amplitude streaks

    Science.gov (United States)

    Ren, Jie; Fu, Song; Hanifi, Ardeshir

    2016-02-01

    Stabilization of two-dimensional disturbances in hypersonic boundary layer flows by finite-amplitude streaks is investigated using nonlinear parabolized stability equations. The boundary-layer flows at Mach numbers 4.5 and 6.0 are studied in which both first and second modes are supported. The streaks considered here are driven either by the so-called optimal perturbations (Klebanoff-type) or the centrifugal instability (Görtler-type). When the streak amplitude is in an appropriate range, i.e., large enough to modulate the laminar boundary layer but low enough to not trigger secondary instability, both first and second modes can effectively be suppressed.

  18. Using ground observations of a digital camera in the VIS-NIR range for quantifying the phenology of Mediterranean woody species

    Science.gov (United States)

    Weil, Gilad; Lensky, Itamar M.; Levin, Noam

    2017-10-01

    The spectral reflectance of most plant species is quite similar, and thus the feasibility of identifying most plant species based on single date multispectral data is very low. Seasonal phenological patterns of plant species may enable to face the challenge of using remote sensing for mapping plant species at the individual level. We used a consumer-grade digital camera with near infra-red capabilities in order to extract and quantify vegetation phenological information in four East Mediterranean sites. After illumination corrections and other noise reduction steps, the phenological patterns of 1839 individuals representing 12 common species were analyzed, including evergreen trees, winter deciduous trees, semi-deciduous summer shrubs and annual herbaceous patches. Five vegetation indices were used to describe the phenology: relative green and red (green/red chromatic coordinate), excess green (ExG), normalized difference vegetation index (NDVI) and green-red vegetation index (GRVI). We found significant differences between the phenology of the various species, and defined the main phenological groups using agglomerative hierarchical clustering. Differences between species and sites regarding the start of season (SOS), maximum of season (MOS) and end of season (EOS) were displayed in detail, using ExG values, as this index was found to have the lowest percentage of outliers. An additional visible band spectral index (relative red) was found as useful for characterizing seasonal phenology, and had the lowest correlation with the other four vegetation indices, which are more sensitive to greenness. We used a linear mixed model in order to evaluate the influences of various factors on the phenology, and found that unlike the significant effect of species and individuals on SOS, MOS and EOS, the sites' location did not have a direct significant effect on the timing of phenological events. In conclusion, the relative advantage of the proposed methodology is the

  19. Seasonal Variations of Mesospheric Gravity Waves Observed with an Airglow All-sky Camera at Mt. Bohyun, Korea (36° N

    Directory of Open Access Journals (Sweden)

    Yong Ha Kim

    2010-09-01

    Full Text Available We have carried out all-sky imaging of OH Meinel, O2 atmospheric and OI 557.7 nm airglow layers in the period from July of 2001 through September of 2005 at Mt. Bohyun, Korea (36.2° N, 128.9° E, Alt = 1,124 m. We analyzed the images observed during a total of 153 clear moonless nights and found 97 events of band-type waves. The characteristics of the observed waves (wavelengths, periods, and phase speeds are consistent with internal gravity waves. The wave occurrence shows an approximately semi-annual variation, with maxima near solstices and minima near equinoxes, which is consistent with other studies of airglow wave observations, but not with those of mesospheric radar/lidar observations. The observed waves tended to propagate westward during fall and winter, and eastward during spring and summer. Our ray tracing study of the observed waves shows that majority of the observed waves seemed to originate from mesospheric altitudes. The preferential directions and the apparent source altitudes can be explained if the observed waves are secondary waves generated from primary waves that have been selected by the filtering process and break up at the mesospheric altitudes.

  20. Analyses of Twelve New Whole Genome Sequences of Cassava Brown Streak Viruses and Ugandan Cassava Brown Streak Viruses from East Africa: Diversity, Supercomputing and Evidence for Further Speciation

    Science.gov (United States)

    Ndunguru, Joseph; Sseruwagi, Peter; Tairo, Fred; Stomeo, Francesca; Maina, Solomon; Djinkeng, Appolinaire; Kehoe, Monica; Boykin, Laura M.

    2015-01-01

    Cassava brown streak disease is caused by two devastating viruses, Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) which are frequently found infecting cassava, one of sub-Saharan Africa’s most important staple food crops. Each year these viruses cause losses of up to $100 million USD and can leave entire families without their primary food source, for an entire year. Twelve new whole genomes, including seven of CBSV and five of UCBSV were uncovered in this research, doubling the genomic sequences available in the public domain for these viruses. These new sequences disprove the assumption that the viruses are limited by agro-ecological zones, show that current diagnostic primers are insufficient to provide confident diagnosis of these viruses and give rise to the possibility that there may be as many as four distinct species of virus. Utilizing NGS sequencing technologies and proper phylogenetic practices will rapidly increase the solution to sustainable cassava production. PMID:26439260

  1. Analyses of Twelve New Whole Genome Sequences of Cassava Brown Streak Viruses and Ugandan Cassava Brown Streak Viruses from East Africa: Diversity, Supercomputing and Evidence for Further Speciation.

    Directory of Open Access Journals (Sweden)

    Joseph Ndunguru

    Full Text Available Cassava brown streak disease is caused by two devastating viruses, Cassava brown streak virus (CBSV and Ugandan cassava brown streak virus (UCBSV which are frequently found infecting cassava, one of sub-Saharan Africa's most important staple food crops. Each year these viruses cause losses of up to $100 million USD and can leave entire families without their primary food source, for an entire year. Twelve new whole genomes, including seven of CBSV and five of UCBSV were uncovered in this research, doubling the genomic sequences available in the public domain for these viruses. These new sequences disprove the assumption that the viruses are limited by agro-ecological zones, show that current diagnostic primers are insufficient to provide confident diagnosis of these viruses and give rise to the possibility that there may be as many as four distinct species of virus. Utilizing NGS sequencing technologies and proper phylogenetic practices will rapidly increase the solution to sustainable cassava production.

  2. Cameras in mobile phones

    Science.gov (United States)

    Nummela, Ville; Viinikanoja, Jarkko; Alakarhu, Juha

    2006-04-01

    One of the fastest growing markets in consumer markets today are camera phones. During past few years total volume has been growing fast and today millions of mobile phones with camera will be sold. At the same time resolution and functionality of the cameras has been growing from CIF towards DSC level. From camera point of view the mobile world is an extremely challenging field. Cameras should have good image quality but in small size. They also need to be reliable and their construction should be suitable for mass manufacturing. All components of the imaging chain should be well optimized in this environment. Image quality and usability are the most important parameters to user. The current trend of adding more megapixels to cameras and at the same time using smaller pixels is affecting both. On the other hand reliability and miniaturization are key drivers for product development as well as the cost. In optimized solution all parameters are in balance but the process of finding the right trade-offs is not an easy task. In this paper trade-offs related to optics and their effects to image quality and usability of cameras are discussed. Key development areas from mobile phone camera point of view are also listed.

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

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... African Journal of Biotechnology Vol. ... development ... Biotechnology Center, Kenya Agricultural Research Institute, P.O. Box 58711-00200, Nairobi, ... Maize streak virus disease is an important disease of maize in Kenya.

  4. Thermal Cameras and Applications

    DEFF Research Database (Denmark)

    Gade, Rikke; Moeslund, Thomas B.

    2014-01-01

    Thermal cameras are passive sensors that capture the infrared radiation emitted by all objects with a temperature above absolute zero. This type of camera was originally developed as a surveillance and night vision tool for the military, but recently the price has dropped, significantly opening up...... a broader field of applications. Deploying this type of sensor in vision systems eliminates the illumination problems of normal greyscale and RGB cameras. This survey provides an overview of the current applications of thermal cameras. Applications include animals, agriculture, buildings, gas detection......, industrial, and military applications, as well as detection, tracking, and recognition of humans. Moreover, this survey describes the nature of thermal radiation and the technology of thermal cameras....

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

    Science.gov (United States)

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

    2013-06-12

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

  6. Spatiotemporal mechanical variation reveals critical role for rho kinase during primitive streak morphogenesis.

    Science.gov (United States)

    Henkels, Julia; Oh, Jaeho; Xu, Wenwei; Owen, Drew; Sulchek, Todd; Zamir, Evan

    2013-02-01

    Large-scale morphogenetic movements during early embryo development are driven by complex changes in biochemical and biophysical factors. Current models for amniote primitive streak morphogenesis and gastrulation take into account numerous genetic pathways but largely ignore the role of mechanical forces. Here, we used atomic force microscopy (AFM) to obtain for the first time precise biomechanical properties of the early avian embryo. Our data reveal that the primitive streak is significantly stiffer than neighboring regions of the epiblast, and that it is stiffer than the pre-primitive streak epiblast. To test our hypothesis that these changes in mechanical properties are due to a localized increase of actomyosin contractility, we inhibited actomyosin contractility via the Rho kinase (ROCK) pathway using the small-molecule inhibitor Y-27632. Our results using several different assays show the following: (1) primitive streak formation was blocked; (2) the time-dependent increase in primitive streak stiffness was abolished; and (3) convergence of epiblast cells to the midline was inhibited. Taken together, our data suggest that actomyosin contractility is necessary for primitive streak morphogenesis, and specifically, ROCK plays a critical role. To better understand the underlying mechanisms of this fundamental process, future models should account for the findings presented in this study.

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

    Directory of Open Access Journals (Sweden)

    Febrilia Nur'aini

    2014-12-01

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

  8. Effects of Hot Streak Shape on Rotor Heating in a High-Subsonic Single-Stage Turbine

    Science.gov (United States)

    Dorney, Daniel J.; Gundy-Burlet, Karen L.; Norvig, Peter (Technical Monitor)

    1999-01-01

    Experimental data have shown that combustor temperature non-uniformities can lead to the excessive heating of first-stage rotor blades in turbines. This heating of the rotor blades can lead to thermal fatigue and degrade turbine performance. The results of recent studies have shown that variations in the circumferential location (clocking) of the hot streak relative to the first-stage vane airfoils can be used to minimize the adverse effects of the hot streak. The effects of the hot streak/airfoil count ratio on the heating patterns of turbine airfoils have also been evaluated. In the present investigation, three-dimensional unsteady Navier-Stokes simulations have been performed for a single-stage high-pressure turbine operating in high subsonic flow. In addition to a simulation of the baseline turbine, simulations have been performed for circular and elliptical hot streaks of varying sizes in an effort to represent different combustor designs. The predicted results for the baseline simulation show good agreement with the available experimental data. The results of the hot streak simulations indicate: that a) elliptical hot streaks mix more rapidly than circular hot streaks, b) for small hot streak surface area the average rotor temperature is not a strong function of hot streak temperature ratio or shape, and c) hot streaks with larger surface area interact with the secondary flows at the rotor hub endwall, generating an additional high temperature region.

  9. XSST/TRC rocket observations of July 13, 1982 flare. [X-ray Spectrometer, Spectrograph and Telescope/Transition Region Camera

    Science.gov (United States)

    Foing, Bernard H.; Bonnet, Roger M.; Dame, Luc; Bruner, Marilyn; Acton, Loren W.

    1986-01-01

    The present analysis of UV filtergrams of the July 13, 1982 solar flare obtained by the XSST/TRC rocket experiments has used calibrated intensities of the flare components to directly estimate the Lyman-alpha line flux, C IV line flux, and excess 160-nm continuum temperature brighness over the underlying plage. The values obtained are small by comparison with other observed or calculated equivalent quantities from the Machado (1980) model of flare F1. The corresponding power required to heat up to the temperature minimum over the 1200 sq Mm area is found to be 3.6 x 10 to the 25th erg/sec for this small X-ray C6 flare, 7 min after the ground-based observed flare maximum.

  10. Avoiding acidic region streaking in two-dimensional gel electrophoresis: case study with two bacterial whole cell protein extracts.

    Science.gov (United States)

    Roy, Arnab; Varshney, Umesh; Pal, Debnath

    2014-09-01

    Acidic region streaking (ARS) is one of the lacunae in two-dimensional gel electrophoresis (2DE) of bacterial proteome. This streaking is primarily caused by nucleic acid (NuA) contamination and poses major problem in the downstream processes like image analysis and protein identification. Although cleanup and nuclease digestion are practiced as remedial options, these strategies may incur loss in protein recovery and perform incomplete removal of NuA. As a result, ARS has remained a common observation across publications, including the recent ones. In this work, we demonstrate how ultrasound wave can be used to shear NuA in plain ice-cooled water, facilitating the elimination of ARS in the 2DE gels without the need for any additional sample cleanup tasks. In combination with a suitable buffer recipe, IEF program and frequent paper-wick changing approach, we are able to reproducibly demonstrate the production of clean 2DE gels with improved protein recovery and negligible or no ARS. We illustrate our procedure using whole cell protein extracts from two diverse organisms, Escherichia coli and Mycobacterium smegmatis. Our designed protocols are straightforward and expected to provide good 2DE gels without ARS, with comparable times and significantly lower cost.

  11. Advanced CCD camera developments

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-11-15

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

  12. Gamma camera system

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.; Schlosser, P.A.; Steidley, J.W.

    1980-01-01

    A detailed description is given of a novel gamma camera which is designed to produce superior images than conventional cameras used in nuclear medicine. The detector consists of a solid state detector (e.g. germanium) which is formed to have a plurality of discrete components to enable 2-dimensional position identification. Details of the electronic processing circuits are given and the problems and limitations introduced by noise are discussed in full. (U.K.)

  13. Neutron cameras for ITER

    International Nuclear Information System (INIS)

    Johnson, L.C.; Barnes, C.W.; Batistoni, P.

    1998-01-01

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

  14. Novel technique for addressing streak artifact in gated dual-source MDCT angiography utilizing ECG-editing

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Laura T.; Boll, Daniel T. [Duke University Medical Center, Department of Radiology, Box 3808, Durham, NC (United States)

    2008-11-15

    Streak artifact is an important source of image degradation in computed tomographic imaging. In coronary MDCT angiography, streak artifact from pacemaker leads in the SVC can render segments of the right coronary artery uninterpretable. With current technology in clinical practice, there is no effective way to eliminate streak artifact in coronary MDCT angiography entirely. We propose a technique to minimize the impact of streak artifact in retrospectively gated coronary MDCT angiography by utilizing small shifts in the reconstruction window. In our experience, previously degraded portions of the coronary vasculature were able to be well evaluated using this technique. (orig.)

  15. Ultradeep Infrared Array Camera Observations of Sub-L* z ~ 7 and z ~ 8 Galaxies in the Hubble Ultra Deep Field: the Contribution of Low-Luminosity Galaxies to the Stellar Mass Density and Reionization

    Science.gov (United States)

    Labbé, I.; González, V.; Bouwens, R. J.; Illingworth, G. D.; Oesch, P. A.; van Dokkum, P. G.; Carollo, C. M.; Franx, M.; Stiavelli, M.; Trenti, M.; Magee, D.; Kriek, M.

    2010-01-01

    We study the Spitzer Infrared Array Camera (IRAC) mid-infrared (rest-frame optical) fluxes of 14 newly WFC3/IR-detected z ~ 7 z 850-dropout galaxies and 5z ~ 8 Y 105-dropout galaxies. The WFC3/IR depth and spatial resolution allow accurate removal of contaminating foreground light, enabling reliable flux measurements at 3.6 μm and 4.5 μm. None of the galaxies are detected to [3.6] ≈ 26.9 (AB, 2σ), but a stacking analysis reveals a robust detection for the z 850-dropouts and an upper limit for the Y 105-dropouts. We construct average broadband spectral energy distributions using the stacked Advanced Camera for Surveys (ACS), WFC3, and IRAC fluxes and fit stellar population synthesis models to derive mean redshifts, stellar masses, and ages. For the z 850-dropouts, we find z = 6.9+0.1 -0.1, (U - V)rest ≈ 0.4, reddening AV = 0, stellar mass langM*rang = 1.2+0.3 -0.6 × 109 M sun (Salpeter initial mass function). The best-fit ages ~300 Myr, M/LV ≈ 0.2, and SSFR ~1.7 Gyr-1 are similar to values reported for luminous z ~ 7 galaxies, indicating the galaxies are smaller but not much younger. The sub-L* galaxies observed here contribute significantly to the stellar mass density and under favorable conditions may have provided enough photons for sustained reionization at 7 dropouts have stellar masses that are uncertain by 1.5 dex due to the near-complete reliance on far-UV data. Adopting the 2σ upper limit on the M/L(z = 8), the stellar mass density to M UV,AB Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs #11563, 9797. Based on observations with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Support for this work was provided by NASA through contract 125790 issued by JPL/Caltech. Based on service mode observations collected at the European Southern Observatory, Paranal, Chile (ESO Program

  16. Electron streaking and dissociation in laser-assisted photoionization of molecular hydrogen

    International Nuclear Information System (INIS)

    Palacios, Alicia; González-Castrillo, Alberto; Martín, Fernando

    2014-01-01

    We report ab initio calculations on laser-assisted photoionization of the hydrogen molecule in the energy region where autoionization from doubly excited states is expected to occur. We use a UV-pump/IR-probe scheme in which an isolated attosecond UV pulse and a 750 nm IR pulse are combined. The IR pulse has a relatively low intensity (10 12 W cm −2 ), which allows us to perform a perturbative analysis of the calculated ionization probabilities differential in either electron or nuclear energy or both. We show that, for dissociative ionization, the electron energy distributions as a function of time delay exhibit unusual streaking patterns that are due to the presence of autoionizing states. These patterns significantly differ from the standard ones observed in direct single ionization of atoms and molecules. We also show that, by using such a pump–probe scheme, one can suppress autoionization from doubly excited states for time delays between 0 and 4 fs. (paper)

  17. The effect of wall temperature distribution on streaks in compressible turbulent boundary layer

    Science.gov (United States)

    Zhang, Zhao; Tao, Yang; Xiong, Neng; Qian, Fengxue

    2018-05-01

    The thermal boundary condition at wall is very important for the compressible flow due to the coupling of the energy equation, and a lot of research works about it were carried out in past decades. In most of these works, the wall was assumed as adiabatic or uniform isothermal surface; the flow over a thermal wall with some special temperature distribution was seldom studied. Lagha studied the effect of uniform isothermal wall on the streaks, and pointed out that higher the wall temperature is, the longer the streak (POF, 2011, 23, 015106). So, we designed streamwise stripes of wall temperature distribution on the compressible turbulent boundary layer at Mach 3.0 to learn the effect on the streaks by means of direct numerical simulation in this paper. The mean wall temperature is equal to the adiabatic case approximately, and the width of the temperature stripes is in the same order as the width of the streaks. The streak patterns in near-wall region with different temperature stripes are shown in the paper. Moreover, we find that there is a reduction of friction velocity with the wall temperature stripes when compared with the adiabatic case.

  18. Autonomous Multicamera Tracking on Embedded Smart Cameras

    Directory of Open Access Journals (Sweden)

    Bischof Horst

    2007-01-01

    Full Text Available There is currently a strong trend towards the deployment of advanced computer vision methods on embedded systems. This deployment is very challenging since embedded platforms often provide limited resources such as computing performance, memory, and power. In this paper we present a multicamera tracking method on distributed, embedded smart cameras. Smart cameras combine video sensing, processing, and communication on a single embedded device which is equipped with a multiprocessor computation and communication infrastructure. Our multicamera tracking approach focuses on a fully decentralized handover procedure between adjacent cameras. The basic idea is to initiate a single tracking instance in the multicamera system for each object of interest. The tracker follows the supervised object over the camera network, migrating to the camera which observes the object. Thus, no central coordination is required resulting in an autonomous and scalable tracking approach. We have fully implemented this novel multicamera tracking approach on our embedded smart cameras. Tracking is achieved by the well-known CamShift algorithm; the handover procedure is realized using a mobile agent system available on the smart camera network. Our approach has been successfully evaluated on tracking persons at our campus.

  19. State of art in radiation tolerant camera

    Energy Technology Data Exchange (ETDEWEB)

    Choi; Young Soo; Kim, Seong Ho; Cho, Jae Wan; Kim, Chang Hoi; Seo, Young Chil

    2002-02-01

    Working in radiation environment such as nuclear power plant, RI facility, nuclear fuel fabrication facility, medical center has to be considered radiation exposure, and we can implement these job by remote observation and operation. However the camera used for general industry is weakened at radiation, so radiation-tolerant camera is needed for radiation environment. The application of radiation-tolerant camera system is nuclear industry, radio-active medical, aerospace, and so on. Specially nuclear industry, the demand is continuous in the inspection of nuclear boiler, exchange of pellet, inspection of nuclear waste. In the nuclear developed countries have been an effort to develop radiation-tolerant cameras. Now they have many kinds of radiation-tolerant cameras which can tolerate to 10{sup 6}-10{sup 8} rad total dose. In this report, we examine into the state-of-art about radiation-tolerant cameras, and analyze these technology. We want to grow up the concern of developing radiation-tolerant camera by this paper, and upgrade the level of domestic technology.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-08

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

  1. Framing-camera tube developed for sub-100-ps range

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    A new framing-camera tube, developed by Electronics Engineering, is capable of recording two-dimensional image frames with high spatial resolution in the sub-100-ps range. Framing is performed by streaking a two-dimensional electron image across narrow slits; the resulting electron-line images from the slits are restored into a framed image by a restorer deflector operating synchronously with the dissector deflector. We have demonstrated its performance in a prototype tube by recording 125-ps-duration framed images of 2.5-mm patterns. The limitation in the framing speed is in the external electronic drivers for the deflectors and not in the tube design characteristics. Shorter frame durations (below 100 ps) can be obtained by use of faster deflection drivers

  2. Neutron imaging system based on a video camera

    International Nuclear Information System (INIS)

    Dinca, M.

    2004-01-01

    possess versatile and unique readout capabilities that have established their utility in scientific and especially for radiation field applications. A detector for neutron radiography based on a cooled CID camera offers some capabilities, as follows: - Extended linear dynamic range up to 109 without blooming or streaking; - Arbitrary pixel selection and nondestructive readout makes it possible to introduce a high degree of exposure control to low-light viewing of static scenes; - Read multiple areas of interest of an image within a given frame at higher rates; - Wide spectral response (185 nm - 1100 nm); - CIDs tolerate high radiation environments up to 3 Mrad integrated dose; - The contiguous pixel structure of CID arrays contributes to accurate imaging because there are virtually no opaque areas between pixels. (author)

  3. Commercialization of radiation tolerant camera

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-01

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

  4. Commercialization of radiation tolerant camera

    International Nuclear Information System (INIS)

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

    1999-12-01

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

  5. Selective-imaging camera

    Science.gov (United States)

    Szu, Harold; Hsu, Charles; Landa, Joseph; Cha, Jae H.; Krapels, Keith A.

    2015-05-01

    How can we design cameras that image selectively in Full Electro-Magnetic (FEM) spectra? Without selective imaging, we cannot use, for example, ordinary tourist cameras to see through fire, smoke, or other obscurants contributing to creating a Visually Degraded Environment (VDE). This paper addresses a possible new design of selective-imaging cameras at firmware level. The design is consistent with physics of the irreversible thermodynamics of Boltzmann's molecular entropy. It enables imaging in appropriate FEM spectra for sensing through the VDE, and displaying in color spectra for Human Visual System (HVS). We sense within the spectra the largest entropy value of obscurants such as fire, smoke, etc. Then we apply a smart firmware implementation of Blind Sources Separation (BSS) to separate all entropy sources associated with specific Kelvin temperatures. Finally, we recompose the scene using specific RGB colors constrained by the HVS, by up/down shifting Planck spectra at each pixel and time.

  6. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each detector ring or offset ring includes a plurality of photomultiplier tubes and a plurality of scintillation crystals are positioned relative to the photomultiplier tubes whereby each tube is responsive to more than one crystal. Each alternate crystal in the ring is offset by one-half or less of the thickness of the crystal such that the staggered crystals are seen by more than one photomultiplier tube. This sharing of crystals and photomultiplier tubes allows identification of the staggered crystal and the use of smaller detectors shared by larger photomultiplier tubes thereby requiring less photomultiplier tubes, creating more scanning slices, providing better data sampling, and reducing the cost of the camera. The offset detector ring geometry reduces the costs of the positron camera and improves its performance

  7. VUV testing of science cameras at MSFC: QE measurement of the CLASP flight cameras

    Science.gov (United States)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, B.; Beabout, D.; Stewart, M.

    2015-08-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras were built and tested for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint MSFC, National Astronomical Observatory of Japan (NAOJ), Instituto de Astrofisica de Canarias (IAC) and Institut D'Astrophysique Spatiale (IAS) sounding rocket mission. The CLASP camera design includes a frame-transfer e2v CCD57-10 512 × 512 detector, dual channel analog readout and an internally mounted cold block. At the flight CCD temperature of -20C, the CLASP cameras exceeded the low-noise performance requirements (UV, EUV and X-ray science cameras at MSFC.

  8. ULTRADEEP INFRARED ARRAY CAMERA OBSERVATIONS OF SUB-L* z ∼ 7 AND z ∼ 8 GALAXIES IN THE HUBBLE ULTRA DEEP FIELD: THE CONTRIBUTION OF LOW-LUMINOSITY GALAXIES TO THE STELLAR MASS DENSITY AND REIONIZATION

    International Nuclear Information System (INIS)

    Labbe, I.; Gonzalez, V.; Bouwens, R. J.; Illingworth, G. D.; Magee, D.; Oesch, P. A.; Carollo, C. M.; Van Dokkum, P. G.; Franx, M.; Stiavelli, M.; Trenti, M.; Kriek, M.

    2010-01-01

    We study the Spitzer Infrared Array Camera (IRAC) mid-infrared (rest-frame optical) fluxes of 14 newly WFC3/IR-detected z ∼ 7 z 850 -dropout galaxies and 5z ∼ 8 Y 105 -dropout galaxies. The WFC3/IR depth and spatial resolution allow accurate removal of contaminating foreground light, enabling reliable flux measurements at 3.6 μm and 4.5 μm. None of the galaxies are detected to [3.6] ∼ 26.9 (AB, 2σ), but a stacking analysis reveals a robust detection for the z 850 -dropouts and an upper limit for the Y 105 -dropouts. We construct average broadband spectral energy distributions using the stacked Advanced Camera for Surveys (ACS), WFC3, and IRAC fluxes and fit stellar population synthesis models to derive mean redshifts, stellar masses, and ages. For the z 850 -dropouts, we find z = 6.9 +0.1 -0.1 , (U - V) rest ∼ 0.4, reddening A V = 0, stellar mass (M*) = 1.2 +0.3 -0.6 x 10 9 M sun (Salpeter initial mass function). The best-fit ages ∼300 Myr, M/L V ∼ 0.2, and SSFR ∼1.7 Gyr -1 are similar to values reported for luminous z ∼ 7 galaxies, indicating the galaxies are smaller but not much younger. The sub-L* galaxies observed here contribute significantly to the stellar mass density and under favorable conditions may have provided enough photons for sustained reionization at 7 +0.1 -0.2 Y 105 -dropouts have stellar masses that are uncertain by 1.5 dex due to the near-complete reliance on far-UV data. Adopting the 2σ upper limit on the M/L(z = 8), the stellar mass density to M UV,AB +1.4 -1.8 x 10 6 M sun Mpc -3 to ρ*(z = 8) 5 M sun Mpc -3 , following ∝(1 + z) -6 over 3 < z < 8. Lower masses at z = 8 would signify more dramatic evolution, which can be established with deeper IRAC observations, long before the arrival of the James Webb Space Telescope.

  9. Precise optical observation of 0.5-GPa shock waves in condensed materials

    Science.gov (United States)

    Nagayama, Kunihito; Mori, Yasuhito

    1999-06-01

    Precision optical observation method was developed to study impact-generated high-pressure shock waves in condensed materials. The present method makes it possible to sensitively detect the shock waves of the relatively low shock stress around 0.5 GPa. The principle of the present method is based on the use of total internal reflection by triangular prisms placed on the free surface of a target assembly. When a plane shock wave arrives at the free surface, the light reflected from the prisms extinguishes instantaneously. The reason is that the total internal reflection changes to the reflection depending on micron roughness of the free surface after the shock arrival. The shock arrival at the bottom face of the prisms can be detected here by two kinds of methods, i.e., a photographic method and a gauge method. The photographic method is an inclined prism method of using a high-speed streak camera. The shock velocity and the shock tilt angle can be estimated accurately from an obtained streak photograph. While in the gauge method, an in-material PVDF stress gauge is combined with an optical prism-pin. The PVDF gauge records electrically the stress profile behind the shockwave front, and the Hugoniot data can be precisely measured by combining the prism pin with the PVDF gauge.

  10. Automatic Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Preuss, Mike

    2014-01-01

    Automatically generating computer animations is a challenging and complex problem with applications in games and film production. In this paper, we investigate howto translate a shot list for a virtual scene into a series of virtual camera configurations — i.e automatically controlling the virtual...

  11. The world's fastest camera

    CERN Multimedia

    Piquepaille, Roland

    2006-01-01

    This image processor is not your typical digital camera. It took 6 years to 20 people and $6 million to build the "Regional Calorimeter Trigger"(RCT) which will be a component of the Compact Muon Solenoid (CMS) experiment, one of the detectors on the Large Hadron Collider (LHC) in Geneva, Switzerland (1 page)

  12. Camera network video summarization

    Science.gov (United States)

    Panda, Rameswar; Roy-Chowdhury, Amit K.

    2017-05-01

    Networks of vision sensors are deployed in many settings, ranging from security needs to disaster response to environmental monitoring. Many of these setups have hundreds of cameras and tens of thousands of hours of video. The difficulty of analyzing such a massive volume of video data is apparent whenever there is an incident that requires foraging through vast video archives to identify events of interest. As a result, video summarization, that automatically extract a brief yet informative summary of these videos, has attracted intense attention in the recent years. Much progress has been made in developing a variety of ways to summarize a single video in form of a key sequence or video skim. However, generating a summary from a set of videos captured in a multi-camera network still remains as a novel and largely under-addressed problem. In this paper, with the aim of summarizing videos in a camera network, we introduce a novel representative selection approach via joint embedding and capped l21-norm minimization. The objective function is two-fold. The first is to capture the structural relationships of data points in a camera network via an embedding, which helps in characterizing the outliers and also in extracting a diverse set of representatives. The second is to use a capped l21-norm to model the sparsity and to suppress the influence of data outliers in representative selection. We propose to jointly optimize both of the objectives, such that embedding can not only characterize the structure, but also indicate the requirements of sparse representative selection. Extensive experiments on standard multi-camera datasets well demonstrate the efficacy of our method over state-of-the-art methods.

  13. The Use of Camera Traps in Wildlife

    Directory of Open Access Journals (Sweden)

    Yasin Uçarlı

    2013-11-01

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

  14. The REM Observing Software

    Directory of Open Access Journals (Sweden)

    Mauro Stefanon

    2010-01-01

    Together they grant the system safety, automatically schedule and perform observations with two simultaneous cameras of user-defined targets, and drive fast reaction to satellite alerts. Subsequent data reduction is left to pipelines managed by each camera.

  15. Nuclear import of Maize fine streak virus proteins in Drosophila S2 cells

    Science.gov (United States)

    Maize fine streak virus (MFSV) is a member of the genus Nucleorhabdovirus, family Rhabdoviridae and is transmitted by the leafhopper Graminella nigrifons. The virus replicates in both its plant host and in its insect vector. Nucleorhabdoviruses replicate in the nucleus and assemble at the inner nu...

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2015-04-01

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

  18. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each ring contains a plurality of scintillation detectors which are positioned around an inner circumference with a septum ring extending inwardly from the inner circumference along each outer edge of each ring. An additional septum ring is positioned in the middle of each ring of detectors and parallel to the other septa rings, whereby the inward extent of all the septa rings may be reduced by one-half and the number of detectors required in each ring is reduced. The additional septa reduces the costs of the positron camera and improves its performance

  19. Gamma ray camera

    International Nuclear Information System (INIS)

    Wang, S.-H.; Robbins, C.D.

    1979-01-01

    An Anger gamma ray camera is improved by the substitution of a gamma ray sensitive, proximity type image intensifier tube for the scintillator screen in the Anger camera. The image intensifier tube has a negatively charged flat scintillator screen, a flat photocathode layer, and a grounded, flat output phosphor display screen, all of which have the same dimension to maintain unit image magnification; all components are contained within a grounded metallic tube, with a metallic, inwardly curved input window between the scintillator screen and a collimator. The display screen can be viewed by an array of photomultipliers or solid state detectors. There are two photocathodes and two phosphor screens to give a two stage intensification, the two stages being optically coupled by a light guide. (author)

  20. Scanning gamma camera

    International Nuclear Information System (INIS)

    Engdahl, L.W.; Batter, J.F. Jr.; Stout, K.J.

    1977-01-01

    A scanning system for a gamma camera providing for the overlapping of adjacent scan paths is described. A collimator mask having tapered edges provides for a graduated reduction in intensity of radiation received by a detector thereof, the reduction in intensity being graduated in a direction normal to the scanning path to provide a blending of images of adjacent scan paths. 31 claims, 15 figures

  1. Gamma camera display system

    International Nuclear Information System (INIS)

    Stout, K.J.

    1976-01-01

    A gamma camera having an array of photomultipliers coupled via pulse shaping circuitry and a resistor weighting circuit to a display for forming an image of a radioactive subject is described. A linearizing circuit is coupled to the weighting circuit, the linearizing circuit including a nonlinear feedback circuit with diode coupling to the weighting circuit for linearizing the correspondence between points of the display and points of the subject. 4 Claims, 5 Drawing Figures

  2. Comparison of polarimetric cameras

    Science.gov (United States)

    2017-03-01

    Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget , Paperwork Reduction Project (0704-0188...polarimetric camera, remote sensing, space systems 15. NUMBER OF PAGES 93 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18...2016. Hermann Hall, Monterey, CA. The next data in Figure 37. were collected on 01 December 2016 at 1226 PST on the rooftop of the Marriot Hotel in

  3. Camera Trajectory fromWide Baseline Images

    Science.gov (United States)

    Havlena, M.; Torii, A.; Pajdla, T.

    2008-09-01

    suggested in to draw 5-tuples from the list of tentative matches ordered ascendingly by the distance of their descriptors which may help to reduce the number of samples in RANSAC. From each 5-tuple, relative orientation is computed by solving the 5-point minimal relative orientation problem for calibrated cameras. Often, there are more models which are supported by a large number of matches. Thus the chance that the correct model, even if it has the largest support, will be found by running a single RANSAC is small. Work suggested to generate models by randomized sampling as in RANSAC but to use soft (kernel) voting for a parameter instead of looking for the maximal support. The best model is then selected as the one with the parameter closest to the maximum in the accumulator space. In our case, we vote in a two-dimensional accumulator for the estimated camera motion direction. However, unlike in, we do not cast votes directly by each sampled epipolar geometry but by the best epipolar geometries recovered by ordered sampling of RANSAC. With our technique, we could go up to the 98.5 % contamination of mismatches with comparable effort as simple RANSAC does for the contamination by 84 %. The relative camera orientation with the motion direction closest to the maximum in the voting space is finally selected. As already mentioned in the first paragraph, the use of camera trajectory estimates is quite wide. In we have introduced a technique for measuring the size of camera translation relatively to the observed scene which uses the dominant apical angle computed at the reconstructed scene points and is robust against mismatches. The experiments demonstrated that the measure can be used to improve the robustness of camera path computation and object recognition for methods which use a geometric, e.g. the ground plane, constraint such as does for the detection of pedestrians. Using the camera trajectories, perspective cutouts with stabilized horizon are constructed and an

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

    Science.gov (United States)

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

    2017-12-01

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

  5. Radiation-resistant camera tube

    International Nuclear Information System (INIS)

    Kuwahata, Takao; Manabe, Sohei; Makishima, Yasuhiro

    1982-01-01

    It was a long time ago that Toshiba launched on manufacturing black-and-white radiation-resistant camera tubes employing nonbrowning face-plate glass for ITV cameras used in nuclear power plants. Now in compliance with the increasing demand in nuclear power field, the Company is at grips with the development of radiation-resistant single color-camera tubes incorporating a color-stripe filter for color ITV cameras used under radiation environment. Herein represented are the results of experiments on characteristics of materials for single color-camera tubes and prospects for commercialization of the tubes. (author)

  6. Camera Movement in Narrative Cinema

    DEFF Research Database (Denmark)

    Nielsen, Jakob Isak

    2007-01-01

    section unearths what characterizes the literature on camera movement. The second section of the dissertation delineates the history of camera movement itself within narrative cinema. Several organizational principles subtending the on-screen effect of camera movement are revealed in section two...... but they are not organized into a coherent framework. This is the task that section three meets in proposing a functional taxonomy for camera movement in narrative cinema. Two presumptions subtend the taxonomy: That camera movement actively contributes to the way in which we understand the sound and images on the screen......, commentative or valuative manner. 4) Focalization: associating the movement of the camera with the viewpoints of characters or entities in the story world. 5) Reflexive: inviting spectators to engage with the artifice of camera movement. 6) Abstract: visualizing abstract ideas and concepts. In order...

  7. Characterization of SWIR cameras by MRC measurements

    Science.gov (United States)

    Gerken, M.; Schlemmer, H.; Haan, Hubertus A.; Siemens, Christofer; Münzberg, M.

    2014-05-01

    Cameras for the SWIR wavelength range are becoming more and more important because of the better observation range for day-light operation under adverse weather conditions (haze, fog, rain). In order to choose the best suitable SWIR camera or to qualify a camera for a given application, characterization of the camera by means of the Minimum Resolvable Contrast MRC concept is favorable as the MRC comprises all relevant properties of the instrument. With the MRC known for a given camera device the achievable observation range can be calculated for every combination of target size, illumination level or weather conditions. MRC measurements in the SWIR wavelength band can be performed widely along the guidelines of the MRC measurements of a visual camera. Typically measurements are performed with a set of resolution targets (e.g. USAF 1951 target) manufactured with different contrast values from 50% down to less than 1%. For a given illumination level the achievable spatial resolution is then measured for each target. The resulting curve is showing the minimum contrast that is necessary to resolve the structure of a target as a function of spatial frequency. To perform MRC measurements for SWIR cameras at first the irradiation parameters have to be given in radiometric instead of photometric units which are limited in their use to the visible range. In order to do so, SWIR illumination levels for typical daylight and twilight conditions have to be defined. At second, a radiation source is necessary with appropriate emission in the SWIR range (e.g. incandescent lamp) and the irradiance has to be measured in W/m2 instead of Lux = Lumen/m2. At third, the contrast values of the targets have to be calibrated newly for the SWIR range because they typically differ from the values determined for the visual range. Measured MRC values of three cameras are compared to the specified performance data of the devices and the results of a multi-band in-house designed Vis-SWIR camera

  8. Lessons Learned from Crime Caught on Camera

    DEFF Research Database (Denmark)

    Lindegaard, Marie Rosenkrantz; Bernasco, Wim

    2018-01-01

    Objectives: The widespread use of camera surveillance in public places offers criminologists the opportunity to systematically and unobtrusively observe crime, their main subject matter. The purpose of this essay is to inform the reader of current developments in research on crimes caught on came...

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

    Directory of Open Access Journals (Sweden)

    Alaine F. Camfield

    2011-12-01

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

  10. Calibration of the cameras of the H.E.S.S. {gamma}-ray astronomy experiment and observations of the Galactic Centre above 100 GeV; Etalonnage des cameras de l'experience d'astronomie {gamma} H.E.S.S. et observations du centre galactique au-dela de 100 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Rolland, L

    2005-05-15

    The H.E.S.S. experiment (High Energy Stereoscopic System) consists of four imaging atmospheric Cherenkov telescopes to study the southern astrophysical sources above 100 GeV. This thesis presents the detector as well as the analysis chain. The calibration methods are described in details and the systematic errors on the image amplitude are derived. Then, an analysis based on a semi-analytical model of the electromagnetic shower development in the atmosphere is presented. Tools to reconstruct the energy spectrum and the morphology of the very high energy {gamma}-ray sources are presented and applied to the Crab Nebula. Systematic errors associated to the spectrum analysis are estimated. All these techniques were applied to study the Galactic Centre emission above 100 GeV. The nature of the source detected in 2003 and 2004 observations is still unknown and its spectrum, variability and morphology are studied. Various candidates are proposed, among them the supermassive black hole Sgr A* located at the dynamical centre of the Milky Way, the supernova remnant Sgr A Est or interactions of accelerated particles with the dense medium of this region. In this thesis, the signal was interpreted in terms of dark matter annihilation (neutralinos or Kaluza-Klein bosons) in a dense halo located at the Galactic Centre. This analysis showed that, in the framework of these models, dark matter annihilation alone can not explain the H.E.S.S. signal. The main component would thus come from astrophysical sources. (author)

  11. Automatic inference of geometric camera parameters and inter-camera topology in uncalibrated disjoint surveillance cameras

    Science.gov (United States)

    den Hollander, Richard J. M.; Bouma, Henri; Baan, Jan; Eendebak, Pieter T.; van Rest, Jeroen H. C.

    2015-10-01

    Person tracking across non-overlapping cameras and other types of video analytics benefit from spatial calibration information that allows an estimation of the distance between cameras and a relation between pixel coordinates and world coordinates within a camera. In a large environment with many cameras, or for frequent ad-hoc deployments of cameras, the cost of this calibration is high. This creates a barrier for the use of video analytics. Automating the calibration allows for a short configuration time, and the use of video analytics in a wider range of scenarios, including ad-hoc crisis situations and large scale surveillance systems. We show an autocalibration method entirely based on pedestrian detections in surveillance video in multiple non-overlapping cameras. In this paper, we show the two main components of automatic calibration. The first shows the intra-camera geometry estimation that leads to an estimate of the tilt angle, focal length and camera height, which is important for the conversion from pixels to meters and vice versa. The second component shows the inter-camera topology inference that leads to an estimate of the distance between cameras, which is important for spatio-temporal analysis of multi-camera tracking. This paper describes each of these methods and provides results on realistic video data.

  12. Explosive Transient Camera (ETC) Program

    Science.gov (United States)

    Ricker, George

    1991-01-01

    Since the inception of the ETC program, a wide range of new technologies was developed to support this astronomical instrument. The prototype unit was installed at ETC Site 1. The first partially automated observations were made and some major renovations were later added to the ETC hardware. The ETC was outfitted with new thermoelectrically-cooled CCD cameras and a sophisticated vacuum manifold, which, together, made the ETC a much more reliable unit than the prototype. The ETC instrumentation and building were placed under full computer control, allowing the ETC to operate as an automated, autonomous instrument with virtually no human intervention necessary. The first fully-automated operation of the ETC was performed, during which the ETC monitored the error region of the repeating soft gamma-ray burster SGR 1806-21.

  13. Wheat streak mosaic virus coat protein is a host-specific long-distance transport determinant in oat

    Science.gov (United States)

    Viral determinants involved in systemic infection of hosts by monocot-infecting plant viruses are poorly understood. Wheat streak mosaic virus (WSMV, genus Tritimovirus, family Potyviridae) exclusively infects monocotyledonous crops such as wheat, oat, barley, maize, triticale, and rye. Previously, ...

  14. Hubble Space Telescope  Wide Field Camera 3 Observations of Escaping Lyman Continuum Radiation from Galaxies and Weak AGN at Redshifts z ∼ 2.3–4.1

    Science.gov (United States)

    Smith, Brent M.; Windhorst, Rogier A.; Jansen, Rolf A.; Cohen, Seth H.; Jiang, Linhua; Dijkstra, Mark; Koekemoer, Anton M.; Bielby, Richard; Inoue, Akio K.; MacKenty, John W.; O’Connell, Robert W.; Silk, Joseph I.

    2018-02-01

    We present observations of escaping Lyman Continuum (LyC) radiation from 34 massive star-forming galaxies (SFGs) and 12 weak AGN with reliably measured spectroscopic redshifts at z≃ 2.3{--}4.1. We analyzed Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) mosaics of the Early Release Science (ERS) field in three UVIS filters to sample the rest-frame LyC over this redshift range. With our best current assessment of the WFC3 systematics, we provide 1σ upper limits for the average LyC emission of galaxies at = 2.35, 2.75, and 3.60 to ∼28.5, 28.1, and 30.7 mag in image stacks of 11–15 galaxies in the WFC3/UVIS F225W, F275W, and F336W, respectively. The LyC flux of weak AGN at = 2.62 and 3.32 are detected at 28.3 and 27.4 mag with S/Ns of ∼2.7 and 2.5 in F275W and F336W for stacks of 7 and 3 AGN, respectively, while AGN at = 2.37 are constrained to ≳27.9 mag at 1σ in a stack of 2 AGN. The stacked AGN LyC light profiles are flatter than their corresponding non-ionizing UV continuum profiles out to radii of r≲ 0\\buildrel{\\prime\\prime}\\over{.} 9, which may indicate a radial dependence of porosity in the ISM. With synthetic stellar SEDs fit to UV continuum measurements longward of {{Ly}}α and IGM transmission models, we constrain the absolute LyC escape fractions to {f}{esc}{abs}≃ {22}-22+44% at = 2.35 and ≲55% at = 2.75 and 3.60, respectively. All available data for galaxies, including published work, suggests a more sudden increase of {f}{esc} with redshift at z≃ 2. Dust accumulating in (massive) galaxies over cosmic time correlates with increased H I column density, which may lead to reducing {f}{esc} more suddenly at z≲ 2. This may suggest that SFGs collectively contributed to maintaining cosmic reionization at redshifts z≳ 2{--}4, while AGN likely dominated reionization at z≲ 2.

  15. Optical Photometric Observations of GEO Debris

    Science.gov (United States)

    Seitzer, Patrick; Rodriquez-Cowardin, Heather M.; Barker, Edwin S.; Abercromby, Kira J.; Kelecy, Thomas M.; Horstman, Matt

    2010-01-01

    We report on a continuing program of optical photometric measurements of faint orbital debris at geosynchronous Earth orbit (GEO). These observations can be compared with laboratory studies of actual spacecraft materials in an effort to determine what the faint debris at GEO may be. We have optical observations from Cerro Tololo Inter-American Observatory (CTIO) in Chile of two samples of debris: 1. GEO objects discovered in a survey with the University of Michigan's 0.6-m aperture Curtis-Schmidt telescope MODEST (for Michigan Orbital DEbris Survey Telescope), and then followed up in real-time with the CTIO/SMARTS 0.9-m for orbits and photometry. Our goal is to determine 6 parameter orbits and measure colors for all objects fainter than R = 15 t11 magnitude that are discovered in the MODEST survey. 2. A smaller sample of high area to mass ratio (AMR) objects discovered independently, and acquired using predictions from orbits derived from independent tracking data collected days prior to the observations. Our optical observations in standard astronomical BVRI filters are done with either telescope, and with the telescope tracking the debris object at the object's angular rate. Observations in different filters are obtained sequentially. We have obtained 71 calibrated sequences of R-B-V-I-R magnitudes. A total of 66 of these sequences have 3 or more good measurements in all filters (not contaminated by star streaks or in Earth's shadow). Most of these sequences show brightness variations, but a small subset has observed brightness variations consistent with that expected from observational errors alone. The majority of these stable objects are redder than a solar color in both B-R and R-I. There is no dependence on color with brightness. For a smaller sample of objects we have observed with synchronized CCD cameras on the two telescopes. The CTIO 0.9-m observes in B, and MODEST in R. The CCD cameras are electronically linked together so that the start time and

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

    Science.gov (United States)

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

    2011-12-01

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

  17. Molecular confirmation of Maize rayado fino virus as the Brazilian corn streak virus

    OpenAIRE

    Hammond,Rosemarie Wahnbaeck; Bedendo,Ivan Paulo

    2005-01-01

    Maize rayado fino virus (MRFV), present in various countries in Latin America, has shown similarities to corn streak virus that occurs in Brazil, regarding pathogenic, serological and histological characteristics. In the current report both virus were molecularly compared to confirm the similarities between them. MRFV was identified by nucleic acid hybridization in samples of maize tissues exhibiting symptoms of "corn stunt" disease, collected from two Brazilian States - São Paulo and Minas G...

  18. VUV Testing of Science Cameras at MSFC: QE Measurement of the CLASP Flight Cameras

    Science.gov (United States)

    Champey, Patrick R.; Kobayashi, Ken; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, B.; Beabout, D.; Stewart, M.

    2015-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras were built and tested for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The CLASP camera design includes a frame-transfer e2v CCD57-10 512x512 detector, dual channel analog readout electronics and an internally mounted cold block. At the flight operating temperature of -20 C, the CLASP cameras achieved the low-noise performance requirements (less than or equal to 25 e- read noise and greater than or equal to 10 e-/sec/pix dark current), in addition to maintaining a stable gain of approximately equal to 2.0 e-/DN. The e2v CCD57-10 detectors were coated with Lumogen-E to improve quantum efficiency (QE) at the Lyman- wavelength. A vacuum ultra-violet (VUV) monochromator and a NIST calibrated photodiode were employed to measure the QE of each camera. Four flight-like cameras were tested in a high-vacuum chamber, which was configured to operate several tests intended to verify the QE, gain, read noise, dark current and residual non-linearity of the CCD. We present and discuss the QE measurements performed on the CLASP cameras. We also discuss the high-vacuum system outfitted for testing of UV and EUV science cameras at MSFC.

  19. Rho kinase activity controls directional cell movements during primitive streak formation in the rabbit embryo.

    Science.gov (United States)

    Stankova, Viktoria; Tsikolia, Nikoloz; Viebahn, Christoph

    2015-01-01

    During animal gastrulation, the specification of the embryonic axes is accompanied by epithelio-mesenchymal transition (EMT), the first major change in cell shape after fertilization. EMT takes place in disparate topographical arrangements, such as the circular blastopore of amphibians, the straight primitive streak of birds and mammals or in intermediate gastrulation forms of other amniotes such as reptiles. Planar cell movements are prime candidates to arrange specific modes of gastrulation but there is no consensus view on their role in different vertebrate classes. Here, we test the impact of interfering with Rho kinase-mediated cell movements on gastrulation topography in blastocysts of the rabbit, which has a flat embryonic disc typical for most mammals. Time-lapse video microscopy, electron microscopy, gene expression and morphometric analyses of the effect of inhibiting ROCK activity showed - besides normal specification of the organizer region - a dose-dependent disruption of primitive streak formation; this disruption resulted in circular, arc-shaped or intermediate forms, reminiscent of those found in amphibians, fishes and reptiles. Our results reveal a crucial role of ROCK-controlled directional cell movements during rabbit primitive streak formation and highlight the possibility that temporal and spatial modulation of cell movements were instrumental for the evolution of gastrulation forms. © 2015. Published by The Company of Biologists Ltd.

  20. Target 3-D reconstruction of streak tube imaging lidar based on Gaussian fitting

    Science.gov (United States)

    Yuan, Qingyu; Niu, Lihong; Hu, Cuichun; Wu, Lei; Yang, Hongru; Yu, Bing

    2018-02-01

    Streak images obtained by the streak tube imaging lidar (STIL) contain the distance-azimuth-intensity information of a scanned target, and a 3-D reconstruction of the target can be carried out through extracting the characteristic data of multiple streak images. Significant errors will be caused in the reconstruction result by the peak detection method due to noise and other factors. So as to get a more precise 3-D reconstruction, a peak detection method based on Gaussian fitting of trust region is proposed in this work. Gaussian modeling is performed on the returned wave of single time channel of each frame, then the modeling result which can effectively reduce the noise interference and possesses a unique peak could be taken as the new returned waveform, lastly extracting its feature data through peak detection. The experimental data of aerial target is for verifying this method. This work shows that the peak detection method based on Gaussian fitting reduces the extraction error of the feature data to less than 10%; utilizing this method to extract the feature data and reconstruct the target make it possible to realize the spatial resolution with a minimum 30 cm in the depth direction, and improve the 3-D imaging accuracy of the STIL concurrently.

  1. Oct4 is required ~E7.5 for proliferation in the primitive streak.

    Directory of Open Access Journals (Sweden)

    Brian DeVeale

    2013-11-01

    Full Text Available Oct4 is a widely recognized pluripotency factor as it maintains Embryonic Stem (ES cells in a pluripotent state, and, in vivo, prevents the inner cell mass (ICM in murine embryos from differentiating into trophectoderm. However, its function in somatic tissue after this developmental stage is not well characterized. Using a tamoxifen-inducible Cre recombinase and floxed alleles of Oct4, we investigated the effect of depleting Oct4 in mouse embryos between the pre-streak and headfold stages, ~E6.0-E8.0, when Oct4 is found in dynamic patterns throughout the embryonic compartment of the mouse egg cylinder. We found that depletion of Oct4 ~E7.5 resulted in a severe phenotype, comprised of craniorachischisis, random heart tube orientation, failed turning, defective somitogenesis and posterior truncation. Unlike in ES cells, depletion of the pluripotency factors Sox2 and Oct4 after E7.0 does not phenocopy, suggesting that ~E7.5 Oct4 is required within a network that is altered relative to the pluripotency network. Oct4 is not required in extraembryonic tissue for these processes, but is required to maintain cell viability in the embryo and normal proliferation within the primitive streak. Impaired expansion of the primitive streak occurs coincident with Oct4 depletion ∼E7.5 and precedes deficient convergent extension which contributes to several aspects of the phenotype.

  2. A maize resistance gene functions against bacterial streak disease in rice.

    Science.gov (United States)

    Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

    2005-10-25

    Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, which causes bacterial streak disease. Bacterial streak is an important disease of rice in Asia, and no simply inherited sources of resistance have been identified in rice. Although X. o. pv. oryzicola does not cause disease on maize, we identified a maize gene, Rxo1, that conditions a resistance reaction to a diverse collection of pathogen strains. Surprisingly, Rxo1 also controls resistance to the unrelated pathogen Burkholderia andropogonis, which causes bacterial stripe of sorghum and maize. The same gene thus controls resistance reactions to both pathogens and nonpathogens of maize. Rxo1 has a nucleotide-binding site-leucine-rich repeat structure, similar to many previously identified R genes. Most importantly, Rxo1 functions after transfer as a transgene to rice, demonstrating the feasibility of nonhost R gene transfer between cereals and providing a valuable tool for controlling bacterial streak disease.

  3. cassava brown streak disease effects on leaf metabolites

    African Journals Online (AJOL)

    USER

    Plate 1. Progression of CBSD in cassava leaves with scores 1= leaf from clean plant, no CBSD, 2 = Mild CBSD leaf veinal ... absorb the excess water, after which they were rolled ..... to low carbon dioxide exchange, as observed in sugar cane ...

  4. Video Chat with Multiple Cameras

    OpenAIRE

    MacCormick, John

    2012-01-01

    The dominant paradigm for video chat employs a single camera at each end of the conversation, but some conversations can be greatly enhanced by using multiple cameras at one or both ends. This paper provides the first rigorous investigation of multi-camera video chat, concentrating especially on the ability of users to switch between views at either end of the conversation. A user study of 23 individuals analyzes the advantages and disadvantages of permitting a user to switch between views at...

  5. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

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

  6. A Motionless Camera

    Science.gov (United States)

    1994-01-01

    Omniview, a motionless, noiseless, exceptionally versatile camera was developed for NASA as a receiving device for guiding space robots. The system can see in one direction and provide as many as four views simultaneously. Developed by Omniview, Inc. (formerly TRI) under a NASA Small Business Innovation Research (SBIR) grant, the system's image transformation electronics produce a real-time image from anywhere within a hemispherical field. Lens distortion is removed, and a corrected "flat" view appears on a monitor. Key elements are a high resolution charge coupled device (CCD), image correction circuitry and a microcomputer for image processing. The system can be adapted to existing installations. Applications include security and surveillance, teleconferencing, imaging, virtual reality, broadcast video and military operations. Omniview technology is now called IPIX. The company was founded in 1986 as TeleRobotics International, became Omniview in 1995, and changed its name to Interactive Pictures Corporation in 1997.

  7. Gamma camera system

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.

    1977-01-01

    A gamma camera system having control components operating in conjunction with a solid state detector is described. The detector is formed of a plurality of discrete components which are associated in geometrical or coordinate arrangement defining a detector matrix to derive coordinate signal outputs. These outputs are selectively filtered and summed to form coordinate channel signals and corresponding energy channel signals. A control feature of the invention regulates the noted summing and filtering performance to derive data acceptance signals which are addressed to further treating components. The latter components include coordinate and enery channel multiplexers as well as energy-responsive selective networks. A sequential control is provided for regulating the signal processing functions of the system to derive an overall imaging cycle

  8. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector planes positioned side-by-side around a patient area to detect radiation. Each plane includes a plurality of photomultiplier tubes and at least two rows of scintillation crystals on each photomultiplier tube extend across to adjacent photomultiplier tubes for detecting radiation from the patient area. Each row of crystals on each photomultiplier tube is offset from the other rows of crystals, and the area of each crystal on each tube in each row is different than the area of the crystals on the tube in other rows for detecting which crystal is actuated and allowing the detector to detect more inter-plane slides. The crystals are offset by an amount equal to the length of the crystal divided by the number of rows. The rows of crystals on opposite sides of the patient may be rotated 90 degrees relative to each other

  9. The Circular Camera Movement

    DEFF Research Database (Denmark)

    Hansen, Lennard Højbjerg

    2014-01-01

    It has been an accepted precept in film theory that specific stylistic features do not express specific content. Nevertheless, it is possible to find many examples in the history of film in which stylistic features do express specific content: for instance, the circular camera movement is used...... repeatedly to convey the feeling of a man and a woman falling in love. This raises the question of why producers and directors choose certain stylistic features to narrate certain categories of content. Through the analysis of several short film and TV clips, this article explores whether...... or not there are perceptual aspects related to specific stylistic features that enable them to be used for delimited narrational purposes. The article further attempts to reopen this particular stylistic debate by exploring the embodied aspects of visual perception in relation to specific stylistic features...

  10. Automatic locking radioisotope camera lock

    International Nuclear Information System (INIS)

    Rosauer, P.J.

    1978-01-01

    The lock of the present invention secures the isotope source in a stored shielded condition in the camera until a positive effort has been made to open the lock and take the source outside of the camera and prevents disconnection of the source pigtail unless the source is locked in a shielded condition in the camera. It also gives a visual indication of the locked or possible exposed condition of the isotope source and prevents the source pigtail from being completely pushed out of the camera, even when the lock is released. (author)

  11. LAMOST CCD camera-control system based on RTS2

    Science.gov (United States)

    Tian, Yuan; Wang, Zheng; Li, Jian; Cao, Zi-Huang; Dai, Wei; Wei, Shou-Lin; Zhao, Yong-Heng

    2018-05-01

    The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device (CCD) cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2nd Version (RTS2) is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-framework-based control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.

  12. Camera Layout Design for the Upper Stage Thrust Cone

    Science.gov (United States)

    Wooten, Tevin; Fowler, Bart

    2010-01-01

    Engineers in the Integrated Design and Analysis Division (EV30) use a variety of different tools to aid in the design and analysis of the Ares I vehicle. One primary tool in use is Pro-Engineer. Pro-Engineer is a computer-aided design (CAD) software that allows designers to create computer generated structural models of vehicle structures. For the Upper State thrust cone, Pro-Engineer was used to assist in the design of a layout for two camera housings. These cameras observe the separation between the first and second stage of the Ares I vehicle. For the Ares I-X, one standard speed camera was used. The Ares I design calls for two separate housings, three cameras, and a lighting system. With previous design concepts and verification strategies in mind, a new layout for the two camera design concept was developed with members of the EV32 team. With the new design, Pro-Engineer was used to draw the layout to observe how the two camera housings fit with the thrust cone assembly. Future analysis of the camera housing design will verify the stability and clearance of the camera with other hardware present on the thrust cone.

  13. Improving Photometric Calibration of Meteor Video Camera Systems

    Science.gov (United States)

    Ehlert, Steven; Kingery, Aaron; Suggs, Robert

    2017-01-01

    We present the results of new calibration tests performed by the NASA Meteoroid Environment Office (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the first point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric flux within the camera bandpass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at approx. 0.20 mag, and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to 0.05 - 0.10 mag in both filtered and unfiltered camera observations with no evidence for lingering systematics. These improvements are essential to accurately measuring photometric masses of individual meteors and source mass indexes.

  14. The "All Sky Camera Network"

    Science.gov (United States)

    Caldwell, Andy

    2005-01-01

    In 2001, the "All Sky Camera Network" came to life as an outreach program to connect the Denver Museum of Nature and Science (DMNS) exhibit "Space Odyssey" with Colorado schools. The network is comprised of cameras placed strategically at schools throughout Colorado to capture fireballs--rare events that produce meteorites.…

  15. The Eye of the Camera

    NARCIS (Netherlands)

    van Rompay, Thomas Johannes Lucas; Vonk, Dorette J.; Fransen, M.L.

    2009-01-01

    This study addresses the effects of security cameras on prosocial behavior. Results from previous studies indicate that the presence of others can trigger helping behavior, arising from the need for approval of others. Extending these findings, the authors propose that security cameras can likewise

  16. Overexpression of rice black-streaked dwarf virus p7-1 in Arabidopsis results in male sterility due to non-dehiscent anthers.

    Directory of Open Access Journals (Sweden)

    Feng Sun

    Full Text Available Rice black-streaked dwarf virus (RBSDV, a member of the genus Fijivirus in the family Reoviridae, is propagatively transmitted by the small brown planthopper (Laodelphax striatellus Fallén. RBSDV causes rice black-streaked dwarf and maize rough dwarf diseases, which lead to severe yield losses in crops in China. Although several RBSDV proteins have been studied in detail, the functions of the nonstructural protein P7-1 are still largely unknown. To investigate the role of the P7-1 protein in virus pathogenicity, transgenic Arabidopsis thaliana plants were generated in which the P7-1 gene was expressed under the control of the 35S promoter. The RBSDV P7-1-transgenic Arabidopsis plants (named P7-1-OE were male sterility. Flowers and pollen from P7-1-transgenic plants were of normal size and shape, and anthers developed to the normal size but failed to dehisce. The non-dehiscent anthers observed in P7-1-OE were attributed to decreased lignin content in the anthers. Furthermore, the reactive oxygen species levels were quite low in the transgenic plants compared with the wild type. These results indicate that ectopic expression of the RBSDV P7-1 protein in A. thaliana causes male sterility, possibly through the disruption of the lignin biosynthesis and H2O2-dependent polymerization pathways.

  17. Overexpression of rice black-streaked dwarf virus p7-1 in Arabidopsis results in male sterility due to non-dehiscent anthers.

    Science.gov (United States)

    Sun, Feng; Yuan, Xia; Xu, Qiufang; Zhou, Tong; Fan, Yongjian; Zhou, Yijun

    2013-01-01

    Rice black-streaked dwarf virus (RBSDV), a member of the genus Fijivirus in the family Reoviridae, is propagatively transmitted by the small brown planthopper (Laodelphax striatellus Fallén). RBSDV causes rice black-streaked dwarf and maize rough dwarf diseases, which lead to severe yield losses in crops in China. Although several RBSDV proteins have been studied in detail, the functions of the nonstructural protein P7-1 are still largely unknown. To investigate the role of the P7-1 protein in virus pathogenicity, transgenic Arabidopsis thaliana plants were generated in which the P7-1 gene was expressed under the control of the 35S promoter. The RBSDV P7-1-transgenic Arabidopsis plants (named P7-1-OE) were male sterility. Flowers and pollen from P7-1-transgenic plants were of normal size and shape, and anthers developed to the normal size but failed to dehisce. The non-dehiscent anthers observed in P7-1-OE were attributed to decreased lignin content in the anthers. Furthermore, the reactive oxygen species levels were quite low in the transgenic plants compared with the wild type. These results indicate that ectopic expression of the RBSDV P7-1 protein in A. thaliana causes male sterility, possibly through the disruption of the lignin biosynthesis and H2O2-dependent polymerization pathways.

  18. Gamma camera system

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.

    1982-01-01

    The invention provides a composite solid state detector for use in deriving a display, by spatial coordinate information, of the distribution or radiation emanating from a source within a region of interest, comprising several solid state detector components, each having a given surface arranged for exposure to impinging radiation and exhibiting discrete interactions therewith at given spatially definable locations. The surface of each component and the surface disposed opposite and substantially parallel thereto are associated with impedence means configured to provide for each opposed surface outputs for signals relating the given location of the interactions with one spatial coordinate parameter of one select directional sense. The detector components are arranged to provide groupings of adjacently disposed surfaces mutually linearly oriented to exhibit a common directional sense of the spatial coordinate parameter. Means interconnect at least two of the outputs associated with each of the surfaces within a given grouping for collecting the signals deriving therefrom. The invention also provides a camera system for imaging the distribution of a source of gamma radiation situated within a region of interest

  19. Fog camera to visualize ionizing charged particles

    International Nuclear Information System (INIS)

    Trujillo A, L.; Rodriguez R, N. I.; Vega C, H. R.

    2014-10-01

    The human being can not perceive the different types of ionizing radiation, natural or artificial, present in the nature, for what appropriate detection systems have been developed according to the sensibility to certain radiation type and certain energy type. The objective of this work was to build a fog camera to visualize the traces, and to identify the trajectories, produced by charged particles with high energy, coming mainly of the cosmic rays. The origin of the cosmic rays comes from the solar radiation generated by solar eruptions where the protons compose most of this radiation. It also comes, of the galactic radiation which is composed mainly of charged particles and gamma rays that comes from outside of the solar system. These radiation types have energy time millions higher that those detected in the earth surface, being more important as the height on the sea level increases. These particles in their interaction produce secondary particles that are detectable by means of this cameras type. The camera operates by means of a saturated atmosphere of alcohol vapor. In the moment in that a charged particle crosses the cold area of the atmosphere, the medium is ionized and the particle acts like a condensation nucleus of the alcohol vapor, leaving a visible trace of its trajectory. The built camera was very stable, allowing the detection in continuous form and the observation of diverse events. (Author)

  20. Cloud Computing with Context Cameras

    Science.gov (United States)

    Pickles, A. J.; Rosing, W. E.

    2016-05-01

    We summarize methods and plans to monitor and calibrate photometric observations with our autonomous, robotic network of 2m, 1m and 40cm telescopes. These are sited globally to optimize our ability to observe time-variable sources. Wide field "context" cameras are aligned with our network telescopes and cycle every ˜2 minutes through BVr'i'z' filters, spanning our optical range. We measure instantaneous zero-point offsets and transparency (throughput) against calibrators in the 5-12m range from the all-sky Tycho2 catalog, and periodically against primary standards. Similar measurements are made for all our science images, with typical fields of view of ˜0.5 degrees. These are matched against Landolt, Stetson and Sloan standards, and against calibrators in the 10-17m range from the all-sky APASS catalog. Such measurements provide pretty good instantaneous flux calibration, often to better than 5%, even in cloudy conditions. Zero-point and transparency measurements can be used to characterize, monitor and inter-compare sites and equipment. When accurate calibrations of Target against Standard fields are required, monitoring measurements can be used to select truly photometric periods when accurate calibrations can be automatically scheduled and performed.

  1. Video content analysis on body-worn cameras for retrospective investigation

    NARCIS (Netherlands)

    Bouma, H.; Baan, J.; Haar, F.B. ter; Eendebak, P.T.; Hollander, R.J.M. den; Burghouts, G.J.; Wijn, R.; Broek, S.P. van den; Rest, J.H.C. van

    2015-01-01

    In the security domain, cameras are important to assess critical situations. Apart from fixed surveillance cameras we observe an increasing number of sensors on mobile platforms, such as drones, vehicles and persons. Mobile cameras allow rapid and local deployment, enabling many novel applications

  2. Development of underwater camera using high-definition camera

    International Nuclear Information System (INIS)

    Tsuji, Kenji; Watanabe, Masato; Takashima, Masanobu; Kawamura, Shingo; Tanaka, Hiroyuki

    2012-01-01

    In order to reduce the time for core verification or visual inspection of BWR fuels, the underwater camera using a High-Definition camera has been developed. As a result of this development, the underwater camera has 2 lights and 370 x 400 x 328mm dimensions and 20.5kg weight. Using the camera, 6 or so spent-fuel IDs are identified at 1 or 1.5m distance at a time, and 0.3mmφ pin-hole is recognized at 1.5m distance and 20 times zoom-up. Noises caused by radiation less than 15 Gy/h are not affected the images. (author)

  3. The effect of strong pitch angle scattering on the use of artificial auroral streaks for echo detection - Echo 5

    International Nuclear Information System (INIS)

    Swanson, R.L.; Steffen, J.E.; Winckler, J.R.

    1986-01-01

    During the Echo 5 experiment launched 13 November 1979 from the Poker Flat Research Range (Fairbanks, Alaska), a 0.75 A, 37 keV electron beam was injected both up and down the field line to test the use of optical and X-ray methods to detect the beam as it interacted with the atmosphere below the rocket for both the downward injections (markers) and the upward injected electrons which mirrored at the Southern Hemisphere and returned echoes. The artificial auroral streaks created by the markers were easily visible on the ground TV system but the large intensity of photons produced around the rocket masked any response to the markers by the on-board photometers and X-ray detectors. No echoes were detected with any of the detection systems although the power in some of the upward injections was 7.6 times the power in a detected downward injection thus setting an upper limit on the loss-cone echo flux. The magnitude of the bounce averaged pitch angle diffusion coefficient necessary to explain the lack of observable echoes was found to be 4 x 10 -4 S -1 . It was found that an equatorial wave electric field of 11 mVm -1 would account for the lack of echoes. Such fields should cause strong pitch angle scattering of up to 10 keV natural electrons and thus be consistent with the presence of diffuse aurora on the Echo 5 trajectory. (author)

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

    Science.gov (United States)

    Gayral, Philippe; Iskra-Caruana, Marie-Line

    2009-07-01

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

  5. Streak-photographic investigation of shock wave emission after laser-induced plasma formation in water

    Science.gov (United States)

    Noack, Joachim; Vogel, Alfred

    1995-05-01

    The shock wave emission after dielectric breakdown in water was investigated to assess potential shock wave effects in plasma mediated tissue ablation and intraocular photodisruption. Of particular interest was the dependence of shock wave pressure as a function of distance from the plasma for different laser pulse energies. We have generated plasmas in water with a Nd:YAG laser system delivering pulses of 6 ns duration. The pulses, with energies between 0.4 and 36 mJ (approximately equals 180 times threshold), were focused into a cuvette containing distilled water. The shock wave was visualized with streak photography combined with a schlieren technique. An important advantage of this technique is that the shock position as a function of time can directly be obtained from a single streak and hence a single event. Other methods (e.g. flash photography or passage time measurements between fixed locations) in contrast rely on reproducible events. Using the shock wave speed obtained from the streak images, shock wave peak pressures were calculated providing detailed information on the propagation of the shock. The shock peak pressure as a function of distance r from the optical axis was found to decrease faster than 1/r2 in regions up to distances of 100-150 micrometers . For larger distances it was found to be roughly proportional to 1/r. The scaling law for maximum shock pressure p, at a given distance was found to be proportional to the square root of the laser pulse energy E for distances of 50-200 micrometers from the optical axis.

  6. Polarizing aperture stereoscopic cinema camera

    Science.gov (United States)

    Lipton, Lenny

    2012-07-01

    The art of stereoscopic cinematography has been held back because of the lack of a convenient way to reduce the stereo camera lenses' interaxial to less than the distance between the eyes. This article describes a unified stereoscopic camera and lens design that allows for varying the interaxial separation to small values using a unique electro-optical polarizing aperture design for imaging left and right perspective views onto a large single digital sensor, the size of the standard 35 mm frame, with the means to select left and right image information. Even with the added stereoscopic capability, the appearance of existing camera bodies will be unaltered.

  7. Control system for gamma camera

    International Nuclear Information System (INIS)

    Miller, D.W.

    1977-01-01

    An improved gamma camera arrangement is described which utilizing a solid state detector, formed of high purity germanium. the central arrangement of the camera operates to effect the carrying out of a trapezoidal filtering operation over antisymmetrically summed spatial signals through gated integration procedures utilizing idealized integrating intervals. By simultaneously carrying out peak energy evaluation of the input signals, a desirable control over pulse pile-up phenomena is achieved. Additionally, through the use of the time derivative of incoming pulse or signal energy information to initially enable the control system, a low level information evaluation is provided serving to enhance the signal processing efficiency of the camera

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

    Directory of Open Access Journals (Sweden)

    Siwon Lee

    2015-12-01

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

  9. Binding constants of Southern rice black-streaked dwarf virus Coat Protein with ferulic acid derivatives

    Directory of Open Access Journals (Sweden)

    Longlu Ran

    2018-04-01

    Full Text Available The data present binding constants between ferulic acid derivatives and the Coat Protein (P10 by fluorescence titration in this article, which is hosted in the research article entitled “Interaction Research on an Antiviral Molecule that Targets the Coat Protein of Southern rice black-streaked dwarf virus’’ (Ran et al., 2017 [1]. The data include fluorescence quenching spectrum, Stern–Volmer quenching constants, and binding parameters. In this article, a more comprehensive data interpretation and analysis is explained.

  10. Global Calibration of Multiple Cameras Based on Sphere Targets

    Directory of Open Access Journals (Sweden)

    Junhua Sun

    2016-01-01

    Full Text Available Global calibration methods for multi-camera system are critical to the accuracy of vision measurement. Proposed in this paper is such a method based on several groups of sphere targets and a precision auxiliary camera. Each camera to be calibrated observes a group of spheres (at least three, while the auxiliary camera observes all the spheres. The global calibration can be achieved after each camera reconstructs the sphere centers in its field of view. In the process of reconstructing a sphere center, a parameter equation is used to describe the sphere projection model. Theoretical analysis and computer simulation are carried out to analyze the factors that affect the calibration accuracy. Simulation results show that the parameter equation can largely improve the reconstruction accuracy. In the experiments, a two-camera system calibrated by our method is used to measure a distance about 578 mm, and the root mean squared error is within 0.14 mm. Furthermore, the experiments indicate that the method has simple operation and good flexibility, especially for the onsite multiple cameras without common field of view.

  11. Analyzer for gamma cameras diagnostic

    International Nuclear Information System (INIS)

    Oramas Polo, I.; Osorio Deliz, J. F.; Diaz Garcia, A.

    2013-01-01

    This research work was carried out to develop an analyzer for gamma cameras diagnostic. It is composed of an electronic system that includes hardware and software capabilities, and operates from the acquisition of the 4 head position signals of a gamma camera detector. The result is the spectrum of the energy delivered by nuclear radiation coming from the camera detector head. This system includes analog processing of position signals from the camera, digitization and the subsequent processing of the energy signal in a multichannel analyzer, sending data to a computer via a standard USB port and processing of data in a personal computer to obtain the final histogram. The circuits are composed of an analog processing board and a universal kit with micro controller and programmable gate array. (Author)

  12. Astronomy and the camera obscura

    Science.gov (United States)

    Feist, M.

    2000-02-01

    The camera obscura (from Latin meaning darkened chamber) is a simple optical device with a long history. In the form considered here, it can be traced back to 1550. It had its heyday during the Victorian era when it was to be found at the seaside as a tourist attraction or sideshow. It was also used as an artist's drawing aid and, in 1620, the famous astronomer-mathematician, Johannes Kepler used a small tent camera obscura to trace the scenery.

  13. The future of consumer cameras

    Science.gov (United States)

    Battiato, Sebastiano; Moltisanti, Marco

    2015-03-01

    In the last two decades multimedia, and in particular imaging devices (camcorders, tablets, mobile phones, etc.) have been dramatically diffused. Moreover the increasing of their computational performances, combined with an higher storage capability, allows them to process large amount of data. In this paper an overview of the current trends of consumer cameras market and technology will be given, providing also some details about the recent past (from Digital Still Camera up today) and forthcoming key issues.

  14. Science, conservation, and camera traps

    Science.gov (United States)

    Nichols, James D.; Karanth, K. Ullas; O'Connel, Allan F.; O'Connell, Allan F.; Nichols, James D.; Karanth, K. Ullas

    2011-01-01

    Biologists commonly perceive camera traps as a new tool that enables them to enter the hitherto secret world of wild animals. Camera traps are being used in a wide range of studies dealing with animal ecology, behavior, and conservation. Our intention in this volume is not to simply present the various uses of camera traps, but to focus on their use in the conduct of science and conservation. In this chapter, we provide an overview of these two broad classes of endeavor and sketch the manner in which camera traps are likely to be able to contribute to them. Our main point here is that neither photographs of individual animals, nor detection history data, nor parameter estimates generated from detection histories are the ultimate objective of a camera trap study directed at either science or management. Instead, the ultimate objectives are best viewed as either gaining an understanding of how ecological systems work (science) or trying to make wise decisions that move systems from less desirable to more desirable states (conservation, management). Therefore, we briefly describe here basic approaches to science and management, emphasizing the role of field data and associated analyses in these processes. We provide examples of ways in which camera trap data can inform science and management.

  15. Computing camera heading: A study

    Science.gov (United States)

    Zhang, John Jiaxiang

    2000-08-01

    An accurate estimate of the motion of a camera is a crucial first step for the 3D reconstruction of sites, objects, and buildings from video. Solutions to the camera heading problem can be readily applied to many areas, such as robotic navigation, surgical operation, video special effects, multimedia, and lately even in internet commerce. From image sequences of a real world scene, the problem is to calculate the directions of the camera translations. The presence of rotations makes this problem very hard. This is because rotations and translations can have similar effects on the images, and are thus hard to tell apart. However, the visual angles between the projection rays of point pairs are unaffected by rotations, and their changes over time contain sufficient information to determine the direction of camera translation. We developed a new formulation of the visual angle disparity approach, first introduced by Tomasi, to the camera heading problem. Our new derivation makes theoretical analysis possible. Most notably, a theorem is obtained that locates all possible singularities of the residual function for the underlying optimization problem. This allows identifying all computation trouble spots beforehand, and to design reliable and accurate computational optimization methods. A bootstrap-jackknife resampling method simultaneously reduces complexity and tolerates outliers well. Experiments with image sequences show accurate results when compared with the true camera motion as measured with mechanical devices.

  16. Persistence of Smectic-A Oily Streaks into the Nematic Phase by UV Irradiation of Reactive Mesogens

    Directory of Open Access Journals (Sweden)

    Ines Gharbi

    2017-12-01

    Full Text Available Thin smectic liquid crystal films with competing boundary conditions (planar and homeotropic at opposing surfaces form well-known striated structures known as “oily streaks”, which are a series of hemicylindrical caps that run perpendicular to the easy axis of the planar substrate. The streaks vanish on heating into the nematic phase, where the film becomes uniform and exhibits hybrid alignment. On adding sufficient reactive mesogen and polymerizing, the oily streak texture is maintained on heating through the entire nematic phase until reaching the bulk isotropic phase, above which the texture vanishes. Depending on the liquid crystal thickness, the oily streak structure may be retrieved after cooling, which demonstrates the strong impact of the polymer backbone on the liquid crystal texture. Polarizing optical, atomic force, and scanning electron microscopy data are presented.

  17. Dynamic gamma camera scintigraphy in primary hypoovarism

    International Nuclear Information System (INIS)

    Peshev, N.; Mladenov, B.; Topalov, I.; Tsanev, Ts.

    1988-01-01

    Twenty-seven patients with primary hypoovarism and 10 controls were examined. After intravenous injection of 111 to 175 MBq 99m Tc pertechnetate, dynamic gamma camera scintigraphy for 15 minutes was carried out. In the patients with primary amenorrhea no functioning ovarial tissue was visualized or the ovaries were diminished in size, strongly reduced and non-homogenous accumulation of the radionuclide with unclear and uneven delineation were observed. In the patients with primary infertility, the gamma camera investigation gave information not only about the presence of ovarial parenchyma, but about the extent of the inflammatory process, too. In the patients after surgical intervention, the dynamic radioisotope investigation gave information about the volume and the site of the surgical intervention, as well as about the conditions of the residual parenchyma

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

    Science.gov (United States)

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

    2017-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Conlon Ronald A

    2005-08-01

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

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

    Science.gov (United States)

    Woda, Juliana M; Calzonetti, Teresa; Hilditch-Maguire, Paige; Duyao, Mabel P; Conlon, Ronald A; MacDonald, Marcy E

    2005-08-18

    Huntingtin, the HD gene encoded protein mutated by polyglutamine expansion in Huntington's disease, is required in extraembryonic tissues for proper gastrulation, implicating its activities in nutrition or patterning of the developing embryo. To test these possibilities, we have used whole mount in situ hybridization to examine embryonic patterning and morphogenesis in homozygous Hdh(ex4/5) huntingtin deficient embryos. In the absence of huntingtin, expression of nutritive genes appears normal but E7.0-7.5 embryos exhibit a unique combination of patterning defects. Notable are a shortened primitive streak, absence of a proper node and diminished production of anterior streak derivatives. Reduced Wnt3a, Tbx6 and Dll1 expression signify decreased paraxial mesoderm and reduced Otx2 expression and lack of headfolds denote a failure of head development. In addition, genes initially broadly expressed are not properly restricted to the posterior, as evidenced by the ectopic expression of Nodal, Fgf8 and Gsc in the epiblast and T (Brachyury) and Evx1 in proximal mesoderm derivatives. Despite impaired posterior restriction and anterior streak deficits, overall anterior/posterior polarity is established. A single primitive streak forms and marker expression shows that the anterior epiblast and anterior visceral endoderm (AVE) are specified. Huntingtin is essential in the early patterning of the embryo for formation of the anterior region of the primitive streak, and for down-regulation of a subset of dynamic growth and transcription factor genes. These findings provide fundamental starting points for identifying the novel cellular and molecular activities of huntingtin in the extraembryonic tissues that govern normal anterior streak development. This knowledge may prove to be important for understanding the mechanism by which the dominant polyglutamine expansion in huntingtin determines the loss of neurons in Huntington's disease.

  1. Observation of GEO Satellite Above Thailand’s Sky

    Science.gov (United States)

    Kasonsuwan, K.; Wannawichian, S.; Kirdkao, T.

    2017-09-01

    The direct observations of Geostationary Orbit (GEO) satellites above Thailand’s sky by 0.7-meters telescope were proceeded at Inthanon Mt., Chiang Mai, Thailand. The observation took place at night with Sidereal Stare Mode (SSM). With this observing mode, the moving object will appear as a streak. The star identification for image calibration is based on (1) a star catalogue, (2) the streak detection of the satellite using the software and (3) the extraction of the celestial coordinate of the satellite as a predicted position. Finally, the orbital elements for GEO satellites were calculated.

  2. Prism-based single-camera system for stereo display

    Science.gov (United States)

    Zhao, Yue; Cui, Xiaoyu; Wang, Zhiguo; Chen, Hongsheng; Fan, Heyu; Wu, Teresa

    2016-06-01

    This paper combines the prism and single camera and puts forward a method of stereo imaging with low cost. First of all, according to the principle of geometrical optics, we can deduce the relationship between the prism single-camera system and dual-camera system, and according to the principle of binocular vision we can deduce the relationship between binoculars and dual camera. Thus we can establish the relationship between the prism single-camera system and binoculars and get the positional relation of prism, camera, and object with the best effect of stereo display. Finally, using the active shutter stereo glasses of NVIDIA Company, we can realize the three-dimensional (3-D) display of the object. The experimental results show that the proposed approach can make use of the prism single-camera system to simulate the various observation manners of eyes. The stereo imaging system, which is designed by the method proposed by this paper, can restore the 3-D shape of the object being photographed factually.

  3. Sub-Camera Calibration of a Penta-Camera

    Science.gov (United States)

    Jacobsen, K.; Gerke, M.

    2016-03-01

    Penta cameras consisting of a nadir and four inclined cameras are becoming more and more popular, having the advantage of imaging also facades in built up areas from four directions. Such system cameras require a boresight calibration of the geometric relation of the cameras to each other, but also a calibration of the sub-cameras. Based on data sets of the ISPRS/EuroSDR benchmark for multi platform photogrammetry the inner orientation of the used IGI Penta DigiCAM has been analyzed. The required image coordinates of the blocks Dortmund and Zeche Zollern have been determined by Pix4Dmapper and have been independently adjusted and analyzed by program system BLUH. With 4.1 million image points in 314 images respectively 3.9 million image points in 248 images a dense matching was provided by Pix4Dmapper. With up to 19 respectively 29 images per object point the images are well connected, nevertheless the high number of images per object point are concentrated to the block centres while the inclined images outside the block centre are satisfying but not very strongly connected. This leads to very high values for the Student test (T-test) of the finally used additional parameters or in other words, additional parameters are highly significant. The estimated radial symmetric distortion of the nadir sub-camera corresponds to the laboratory calibration of IGI, but there are still radial symmetric distortions also for the inclined cameras with a size exceeding 5μm even if mentioned as negligible based on the laboratory calibration. Radial and tangential effects of the image corners are limited but still available. Remarkable angular affine systematic image errors can be seen especially in the block Zeche Zollern. Such deformations are unusual for digital matrix cameras, but it can be caused by the correlation between inner and exterior orientation if only parallel flight lines are used. With exception of the angular affinity the systematic image errors for corresponding

  4. World's fastest and most sensitive astronomical camera

    Science.gov (United States)

    2009-06-01

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

  5. Numerical Investigation on the Influence of Hot Streak Temperature Ratio in a High-Pressure Stage of Vaneless Counter-Rotating Turbine

    Directory of Open Access Journals (Sweden)

    Zhao Qingjun

    2007-01-01

    Full Text Available The results of recent studies have shown that combustor exit temperature distortion can cause excessive heat load of high-pressure turbine (HPT rotor blades. The heating of HPT rotor blades can lead to thermal fatigue and degrade turbine performance. In order to explore the influence of hot streak temperature ratio on the temperature distributions of HPT airfoil surface, three-dimensional multiblade row unsteady Navier-Stokes simulations have been performed in a vaneless counter-rotating turbine (VCRT. The hot streak temperature ratios from 1.0 (without hot streak to 2.4 were used in these numerical simulations, including 1.0, 1.2, 1.6, 2.0, and 2.4 temperature ratios. The hot streak is circular in shape with a diameter equal to 25% of the span. The center of the hot streak is located at 50% of span and 0% of pitch (the leading edge of the HPT stator vane. The predicted results show that the hot streak is relatively unaffected as it migrates through the HPT stator. The hot streak mixes with the vane wake and convects towards the pressure surface (PS of the HPT rotor when it moves over the vane surface of the HPT stator. The heat load of the HPT rotor increases with the increase of the hot streak temperature ratio. The existence of the inlet temperature distortion induces a thin layer of cooler air in the HPT rotor, which separates the PS of the HPT rotor from the hotter fluid. The numerical results also indicating the migration characteristics of the hot streak in the HPT rotor are predominated by the combined effects of secondary flow and buoyancy. The combined effects that induce the high-temperature fluid migrate towards the hub on the HPT rotor. The effect of the secondary flow on the hotter fluid increases as the hot streak temperature ratio is increased. The influence of buoyancy is directly proportional to the hot streak temperature ratio. The predicted results show that the increase of the hot streak temperature ratio trends to increase

  6. Event detection intelligent camera development

    International Nuclear Information System (INIS)

    Szappanos, A.; Kocsis, G.; Molnar, A.; Sarkozi, J.; Zoletnik, S.

    2008-01-01

    A new camera system 'event detection intelligent camera' (EDICAM) is being developed for the video diagnostics of W-7X stellarator, which consists of 10 distinct and standalone measurement channels each holding a camera. Different operation modes will be implemented for continuous and for triggered readout as well. Hardware level trigger signals will be generated from real time image processing algorithms optimized for digital signal processor (DSP) and field programmable gate array (FPGA) architectures. At full resolution a camera sends 12 bit sampled 1280 x 1024 pixels with 444 fps which means 1.43 Terabyte over half an hour. To analyse such a huge amount of data is time consuming and has a high computational complexity. We plan to overcome this problem by EDICAM's preprocessing concepts. EDICAM camera system integrates all the advantages of CMOS sensor chip technology and fast network connections. EDICAM is built up from three different modules with two interfaces. A sensor module (SM) with reduced hardware and functional elements to reach a small and compact size and robust action in harmful environment as well. An image processing and control unit (IPCU) module handles the entire user predefined events and runs image processing algorithms to generate trigger signals. Finally a 10 Gigabit Ethernet compatible image readout card functions as the network interface for the PC. In this contribution all the concepts of EDICAM and the functions of the distinct modules are described

  7. A requirement for FGF signalling in the formation of primitive streak-like intermediates from primitive ectoderm in culture.

    Directory of Open Access Journals (Sweden)

    Zhiqiang Zheng

    Full Text Available BACKGROUND: Embryonic stem (ES cells hold considerable promise as a source of cells with therapeutic potential, including cells that can be used for drug screening and in cell replacement therapies. Differentiation of ES cells into the somatic lineages is a regulated process; before the promise of these cells can be realised robust and rational methods for directing differentiation into normal, functional and safe cells need to be developed. Previous in vivo studies have implicated fibroblast growth factor (FGF signalling in lineage specification from pluripotent cells. Although FGF signalling has been suggested as essential for specification of mesoderm and endoderm in vivo and in culture, the exact role of this pathway remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: Using a culture model based on early primitive ectoderm-like (EPL cells we have investigated the role of FGF signalling in the specification of mesoderm. We were unable to demonstrate any mesoderm inductive capability associated with FGF1, 4 or 8 signalling, even when the factors were present at high concentrations, nor any enhancement in mesoderm formation induced by exogenous BMP4. Furthermore, there was no evidence of alteration of mesoderm sub-type formed with addition of FGF1, 4 or 8. Inhibition of endogenous FGF signalling, however, prevented mesoderm and favoured neural differentiation, suggesting FGF signalling was required but not sufficient for the differentiation of primitive ectoderm into primitive streak-like intermediates. The maintenance of ES cell/early epiblast pluripotent marker expression was also observed in cultures when FGF signalling was inhibited. CONCLUSIONS/SIGNIFICANCE: FGF signalling has been shown to be required for the differentiation of primitive ectoderm to neurectoderm. This, coupled with our observations, suggest FGF signalling is required for differentiation of the primitive ectoderm into the germ lineages at gastrulation.

  8. Video camera use at nuclear power plants

    International Nuclear Information System (INIS)

    Estabrook, M.L.; Langan, M.O.; Owen, D.E.

    1990-08-01

    A survey of US nuclear power plants was conducted to evaluate video camera use in plant operations, and determine equipment used and the benefits realized. Basic closed circuit television camera (CCTV) systems are described and video camera operation principles are reviewed. Plant approaches for implementing video camera use are discussed, as are equipment selection issues such as setting task objectives, radiation effects on cameras, and the use of disposal cameras. Specific plant applications are presented and the video equipment used is described. The benefits of video camera use --- mainly reduced radiation exposure and increased productivity --- are discussed and quantified. 15 refs., 6 figs

  9. Design and Construction of an X-ray Lightning Camera

    Science.gov (United States)

    Schaal, M.; Dwyer, J. R.; Rassoul, H. K.; Uman, M. A.; Jordan, D. M.; Hill, J. D.

    2010-12-01

    A pinhole-type camera was designed and built for the purpose of producing high-speed images of the x-ray emissions from rocket-and-wire-triggered lightning. The camera consists of 30 7.62-cm diameter NaI(Tl) scintillation detectors, each sampling at 10 million frames per second. The steel structure of the camera is encased in 1.27-cm thick lead, which blocks x-rays that are less than 400 keV, except through a 7.62-cm diameter “pinhole” aperture located at the front of the camera. The lead and steel structure is covered in 0.16-cm thick aluminum to block RF noise, water and light. All together, the camera weighs about 550-kg and is approximately 1.2-m x 0.6-m x 0.6-m. The image plane, which is adjustable, was placed 32-cm behind the pinhole aperture, giving a field of view of about ±38° in both the vertical and horizontal directions. The elevation of the camera is adjustable between 0 and 50° from horizontal and the camera may be pointed in any azimuthal direction. In its current configuration, the camera’s angular resolution is about 14°. During the summer of 2010, the x-ray camera was located 44-m from the rocket-launch tower at the UF/Florida Tech International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL and several rocket-triggered lightning flashes were observed. In this presentation, I will discuss the design, construction and operation of this x-ray camera.

  10. The GISMO-2 Bolometer Camera

    Science.gov (United States)

    Staguhn, Johannes G.; Benford, Dominic J.; Fixsen, Dale J.; Hilton, Gene; Irwin, Kent D.; Jhabvala, Christine A.; Kovacs, Attila; Leclercq, Samuel; Maher, Stephen F.; Miller, Timothy M.; hide

    2012-01-01

    We present the concept for the GISMO-2 bolometer camera) which we build for background-limited operation at the IRAM 30 m telescope on Pico Veleta, Spain. GISM0-2 will operate Simultaneously in the 1 mm and 2 mm atmospherical windows. The 1 mm channel uses a 32 x 40 TES-based Backshort Under Grid (BUG) bolometer array, the 2 mm channel operates with a 16 x 16 BUG array. The camera utilizes almost the entire full field of view provided by the telescope. The optical design of GISM0-2 was strongly influenced by our experience with the GISMO 2 mm bolometer camera which is successfully operating at the 30m telescope. GISMO is accessible to the astronomical community through the regular IRAM call for proposals.

  11. Dark Energy Camera for Blanco

    Energy Technology Data Exchange (ETDEWEB)

    Binder, Gary A.; /Caltech /SLAC

    2010-08-25

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

  12. Perceptual Color Characterization of Cameras

    Directory of Open Access Journals (Sweden)

    Javier Vazquez-Corral

    2014-12-01

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

  13. EDICAM (Event Detection Intelligent Camera)

    Energy Technology Data Exchange (ETDEWEB)

    Zoletnik, S. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Szabolics, T., E-mail: szabolics.tamas@wigner.mta.hu [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Kocsis, G.; Szepesi, T.; Dunai, D. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary)

    2013-10-15

    Highlights: ► We present EDICAM's hardware modules. ► We present EDICAM's main design concepts. ► This paper will describe EDICAM firmware architecture. ► Operation principles description. ► Further developments. -- Abstract: A new type of fast framing camera has been developed for fusion applications by the Wigner Research Centre for Physics during the last few years. A new concept was designed for intelligent event driven imaging which is capable of focusing image readout to Regions of Interests (ROIs) where and when predefined events occur. At present these events mean intensity changes and external triggers but in the future more sophisticated methods might also be defined. The camera provides 444 Hz frame rate at full resolution of 1280 × 1024 pixels, but monitoring of smaller ROIs can be done in the 1–116 kHz range even during exposure of the full image. Keeping space limitations and the harsh environment in mind the camera is divided into a small Sensor Module and a processing card interconnected by a fast 10 Gbit optical link. This camera hardware has been used for passive monitoring of the plasma in different devices for example at ASDEX Upgrade and COMPASS with the first version of its firmware. The new firmware and software package is now available and ready for testing the new event processing features. This paper will present the operation principle and features of the Event Detection Intelligent Camera (EDICAM). The device is intended to be the central element in the 10-camera monitoring system of the Wendelstein 7-X stellarator.

  14. The Sydney University PAPA camera

    Science.gov (United States)

    Lawson, Peter R.

    1994-04-01

    The Precision Analog Photon Address (PAPA) camera is a photon-counting array detector that uses optical encoding to locate photon events on the output of a microchannel plate image intensifier. The Sydney University camera is a 256x256 pixel detector which can operate at speeds greater than 1 million photons per second and produce individual photon coordinates with a deadtime of only 300 ns. It uses a new Gray coded mask-plate which permits a simplified optical alignment and successfully guards against vignetting artifacts.

  15. Underwater television camera for monitoring inner side of pressure vessel

    International Nuclear Information System (INIS)

    Takayama, Kazuhiko.

    1997-01-01

    An underwater television support device equipped with a rotatable and vertically movable underwater television camera and an underwater television camera controlling device for monitoring images of the inside of the reactor core photographed by the underwater television camera to control the position of the underwater television camera and the underwater light are disposed on an upper lattice plate of a reactor pressure vessel. Both of them are electrically connected with each other by way of a cable to rapidly observe the inside of the reactor core by the underwater television camera. The reproducibility is extremely satisfactory by efficiently concentrating the position of the camera and image information upon inspection and observation. As a result, the steps for periodical inspection can be reduced to shorten the days for the periodical inspection. Since there is no requirement to withdraw fuel assemblies over a wide reactor core region, and the device can be used with the fuel assemblies being left as they are in the reactor, it is suitable for inspection of detectors for nuclear instrumentation. (N.H.)

  16. Wheat streak mosaic virus coat protein is a determinant for vector transmission by the wheat curl mite

    Science.gov (United States)

    Wheat streak mosaic virus (WSMV; genus Tritimovirus; family Potyviridae), is transmitted by the wheat curl mite (Aceria tosichella Keifer). The requirement of coat protein (CP) for WSMV transmission by the wheat curl mite was examined using a series of viable deletion and point mutations. Mite trans...

  17. β-Catenin Regulates Primitive Streak Induction through Collaborative Interactions with SMAD2/SMAD3 and OCT4

    DEFF Research Database (Denmark)

    Funa, Nina Sofi Ayumi; Schachter, Karen; Lerdrup, Mads

    2015-01-01

    Canonical Wnt and Nodal signaling are both required for induction of the primitive streak (PS), which guides organization of the early embryo. The Wnt effector b-catenin is thought to function in these early lineage specification decisions via transcriptional activation of Nodal signaling. Here, we...... specification. This study provides mechanistic insight into how Wnt signaling controls early cell lineage decisions....

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

    Science.gov (United States)

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

  19. 78 FR 24199 - Streak Products, Inc. v. UTi, United States, Inc.; Notice of Filing of Complaint and Assignment

    Science.gov (United States)

    2013-04-24

    ... FEDERAL MARITIME COMMISSION [Docket No. 13--04] Streak Products, Inc. v. UTi, United States, Inc...,'' against UTi, United States, Inc. (``UTi''), hereinafter ``Respondent.'' Complainant states that it is a... therefore, has violated 46 U.S.C. 41104(2). Complainant also alleges that ``UTi engaged in an unfair or...

  20. Effective data-domain noise and streak reduction for X-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhi; Zamyatin, Alexander A. [Toshiba Medical Research Institute USA, Inc., Vernon Hills, IL (United States); Akino, Naruomi [Toshiba Medical System Corporation, Tokyo (Japan)

    2011-07-01

    Streaks and noise caused by photon starvation can seriously impair the diagnostic value of the CT imaging. Existing processing methods often have several parameters to tune. The parameters can be ad hoc to the data sets. Iterative methods can achieve better results, however, at the cost of more hardware resources or longer processing time. This paper reports a new scheme of adaptive Gaussian filtering, which is based on the diffusion-derived scale-space concept. In scale-space view, filtering by Gaussians of different sizes is similar to decompose the data into a sequence of scales. The scale measure, which is the variance of the filter, should be linearly related to the noise standard deviation instead of the variance of the noise. This is a fundamental deviation in the way of using filters. The new filter has only one parameter that remains stable once tuned. Singlepass processing can usually reach the desired results. (orig.)

  1. OCAMS: The OSIRIS-REx Camera Suite

    Science.gov (United States)

    Rizk, B.; Drouet d'Aubigny, C.; Golish, D.; Fellows, C.; Merrill, C.; Smith, P.; Walker, M. S.; Hendershot, J. E.; Hancock, J.; Bailey, S. H.; DellaGiustina, D. N.; Lauretta, D. S.; Tanner, R.; Williams, M.; Harshman, K.; Fitzgibbon, M.; Verts, W.; Chen, J.; Connors, T.; Hamara, D.; Dowd, A.; Lowman, A.; Dubin, M.; Burt, R.; Whiteley, M.; Watson, M.; McMahon, T.; Ward, M.; Booher, D.; Read, M.; Williams, B.; Hunten, M.; Little, E.; Saltzman, T.; Alfred, D.; O'Dougherty, S.; Walthall, M.; Kenagy, K.; Peterson, S.; Crowther, B.; Perry, M. L.; See, C.; Selznick, S.; Sauve, C.; Beiser, M.; Black, W.; Pfisterer, R. N.; Lancaster, A.; Oliver, S.; Oquest, C.; Crowley, D.; Morgan, C.; Castle, C.; Dominguez, R.; Sullivan, M.

    2018-02-01

    The OSIRIS-REx Camera Suite (OCAMS) will acquire images essential to collecting a sample from the surface of Bennu. During proximity operations, these images will document the presence of satellites and plumes, record spin state, enable an accurate model of the asteroid's shape, and identify any surface hazards. They will confirm the presence of sampleable regolith on the surface, observe the sampling event itself, and image the sample head in order to verify its readiness to be stowed. They will document Bennu's history as an example of early solar system material, as a microgravity body with a planetesimal size-scale, and as a carbonaceous object. OCAMS is fitted with three cameras. The MapCam will record color images of Bennu as a point source on approach to the asteroid in order to connect Bennu's ground-based point-source observational record to later higher-resolution surface spectral imaging. The SamCam will document the sample site before, during, and after it is disturbed by the sample mechanism. The PolyCam, using its focus mechanism, will observe the sample site at sub-centimeter resolutions, revealing surface texture and morphology. While their imaging requirements divide naturally between the three cameras, they preserve a strong degree of functional overlap. OCAMS and the other spacecraft instruments will allow the OSIRIS-REx mission to collect a sample from a microgravity body on the same visit during which it was first optically acquired from long range, a useful capability as humanity reaches out to explore near-Earth, Main-Belt and Jupiter Trojan asteroids.

  2. High speed streak techniques for measuring the growth of spark channels

    International Nuclear Information System (INIS)

    Suleebka, P.

    1975-01-01

    The manner of expansion of an electric spark channel is of interest in the understanding of such phenomena as lightning. The development of a camera suitable for photography of this expansion is described, with some results for hydrogen. (author)

  3. The ECM moves during primitive streak formation--computation of ECM versus cellular motion.

    Directory of Open Access Journals (Sweden)

    Evan A Zamir

    2008-10-01

    Full Text Available Galileo described the concept of motion relativity--motion with respect to a reference frame--in 1632. He noted that a person below deck would be unable to discern whether the boat was moving. Embryologists, while recognizing that embryonic tissues undergo large-scale deformations, have failed to account for relative motion when analyzing cell motility data. A century of scientific articles has advanced the concept that embryonic cells move ("migrate" in an autonomous fashion such that, as time progresses, the cells and their progeny assemble an embryo. In sharp contrast, the motion of the surrounding extracellular matrix scaffold has been largely ignored/overlooked. We developed computational/optical methods that measure the extent embryonic cells move relative to the extracellular matrix. Our time-lapse data show that epiblastic cells largely move in concert with a sub-epiblastic extracellular matrix during stages 2 and 3 in primitive streak quail embryos. In other words, there is little cellular motion relative to the extracellular matrix scaffold--both components move together as a tissue. The extracellular matrix displacements exhibit bilateral vortical motion, convergence to the midline, and extension along the presumptive vertebral axis--all patterns previously attributed solely to cellular "migration." Our time-resolved data pose new challenges for understanding how extracellular chemical (morphogen gradients, widely hypothesized to guide cellular trajectories at early gastrulation stages, are maintained in this dynamic extracellular environment. We conclude that models describing primitive streak cellular guidance mechanisms must be able to account for sub-epiblastic extracellular matrix displacements.

  4. Relationship between the shoot characteristics and plant resistance to vascular-streak dieback on cocoa

    Directory of Open Access Journals (Sweden)

    Agung Wahyu Soesilo

    2014-12-01

    Full Text Available Vascular-streak dieback (Oncobasidium theobromae is a serious disease on cocoa damaging the vegetative tissue especially on the branches and leaves. This research was aimed to identify the relationship between characteristics of sprouting ability and VSD resistance to confirm the response of cocoa to pruning treatment on VSD control and developing criteria for selection. Trial was carried out at Kaliwining Experimental Station of ICCRI, a VSD-endemic area by using 668 plants of hybrid populayion which were derivated from intercrossing among seven clones performing different response to VSD. The resistance was evaluated by scoring the plant damage with the scale of 0-6 on drought season in the year of 2009 and 2011. The characteristics of sprouting ability was assessed by recording the pruned trees for the variables of the number of re-growth shoot, shoot height, number of new shoot per pruned branches, shoot diameter and number of leaves per shoot. It was analyzed that the variables of the number of shoot per pruned branches, shoot diameter, shoot height and number of leaves per shoot were not significantly correlated to the score of VSD damage. Grouping of the resistance also performed similar results whereas mean of the sprouting variables were not different among group but the percentage of sprouted branches tend to be higher with the higher of the resistance (lower score. This result confirmed any mechanism of tolerance on VSD resistance by accelerating shoot rejuvenation on resistant plant. Key words : vascular-streak diaback, cocoa, resistance, characteristics of sprouting

  5. Observation of the substructure in the electron bunch on the ACO storage ring

    International Nuclear Information System (INIS)

    Bergher, M.; Velghe, M.; Mialocq, J.P.

    1984-09-01

    In the future, one interesting point of the SRFEL at Orsay will be the microtemporal analysis of the laser beam correlated with that of the electron bunch. In a first time, we have only analysed the temporal structure of the electron bunch with an Electrophotonic streak camera. The first results seem to indicate that the bunch is not an homogeneous bunch but presents a substructure. We discuss with details this data

  6. Visceral endoderm and the primitive streak interact to build the fetal-placental interface of the mouse gastrula.

    Science.gov (United States)

    Rodriguez, Adriana M; Downs, Karen M

    2017-12-01

    Hypoblast/visceral endoderm assists in amniote nutrition, axial positioning and formation of the gut. Here, we provide evidence, currently limited to humans and non-human primates, that hypoblast is a purveyor of extraembryonic mesoderm in the mouse gastrula. Fate mapping a unique segment of axial extraembryonic visceral endoderm associated with the allantoic component of the primitive streak, and referred to as the "AX", revealed that visceral endoderm supplies the placentae with extraembryonic mesoderm. Exfoliation of the AX was dependent upon contact with the primitive streak, which modulated Hedgehog signaling. Resolution of the AX's epithelial-to-mesenchymal transition (EMT) by Hedgehog shaped the allantois into its characteristic projectile and individualized placental arterial vessels. A unique border cell separated the delaminating AX from the yolk sac blood islands which, situated beyond the limit of the streak, were not formed by an EMT. Over time, the AX became the hindgut lip, which contributed extensively to the posterior interface, including both embryonic and extraembryonic tissues. The AX, in turn, imparted antero-posterior (A-P) polarity on the primitive streak and promoted its elongation and differentiation into definitive endoderm. Results of heterotopic grafting supported mutually interactive functions of the AX and primitive streak, showing that together, they self-organized into a complete version of the fetal-placental interface, forming an elongated structure that exhibited A-P polarity and was composed of the allantois, an AX-derived rod-like axial extension reminiscent of the embryonic notochord, the placental arterial vasculature and visceral endoderm/hindgut. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. High-speed holographic camera

    International Nuclear Information System (INIS)

    Novaro, Marc

    The high-speed holographic camera is a disgnostic instrument using holography as an information storing support. It allows us to take 10 holograms, of an object, with exposures times of 1,5ns, separated in time by 1 or 2ns. In order to get these results easily, no mobile part is used in the set-up [fr

  8. The Camera Comes to Court.

    Science.gov (United States)

    Floren, Leola

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

  9. Gamma camera with reflectivity mask

    International Nuclear Information System (INIS)

    Stout, K.J.

    1980-01-01

    In accordance with the present invention there is provided a radiographic camera comprising: a scintillator; a plurality of photodectors positioned to face said scintillator; a plurality of masked regions formed upon a face of said scintillator opposite said photdetectors and positioned coaxially with respective ones of said photodetectors for decreasing the amount of internal reflection of optical photons generated within said scintillator. (auth)

  10. Multiple Sensor Camera for Enhanced Video Capturing

    Science.gov (United States)

    Nagahara, Hajime; Kanki, Yoshinori; Iwai, Yoshio; Yachida, Masahiko

    A resolution of camera has been drastically improved under a current request for high-quality digital images. For example, digital still camera has several mega pixels. Although a video camera has the higher frame-rate, the resolution of a video camera is lower than that of still camera. Thus, the high-resolution is incompatible with the high frame rate of ordinary cameras in market. It is difficult to solve this problem by a single sensor, since it comes from physical limitation of the pixel transfer rate. In this paper, we propose a multi-sensor camera for capturing a resolution and frame-rate enhanced video. Common multi-CCDs camera, such as 3CCD color camera, has same CCD for capturing different spectral information. Our approach is to use different spatio-temporal resolution sensors in a single camera cabinet for capturing higher resolution and frame-rate information separately. We build a prototype camera which can capture high-resolution (2588×1958 pixels, 3.75 fps) and high frame-rate (500×500, 90 fps) videos. We also proposed the calibration method for the camera. As one of the application of the camera, we demonstrate an enhanced video (2128×1952 pixels, 90 fps) generated from the captured videos for showing the utility of the camera.

  11. Camera-cinematography of the heart

    International Nuclear Information System (INIS)

    Adam, W.E.; Meyer, G.; Bitter, F.; Kampmann, H.; Bargon, G.; Stauch, M.; Ulm Univ.

    1975-01-01

    By 'camera-cinematography' of the heart, we mean an isotope method which permits detailed observation of cardiac mechanics without the use of a catheter. All that is necessary is an intravenous injection of 10 to 15 mCisup(99m)Tc human serum albumin followed after ten minutes by a five to ten minute period of observation with a scintillation camera. At this time the isotope has become distributed in the blood. Variations in the precordial impulses correspond with intra-cardiac changes of blood volume during a cardiac cycle. Analysis of the R-wave provides adequate information of cyclical volume changes in limited portions of the heart. This is achieved by a monitor with a pseudo-3-dimensional display; contraction and relaxation of the myocardium can be shown for any chosen longitudinal or horizontal diameter of the heart. Our programme allows simultaneous presentation of the movement of any point on the myocardium as a time-activity curve. The method is recommended as an addition to chest radiography, heart screening or cardiac kymography before carrying out cardiac catheterisation. (orig.) [de

  12. Architectural Design Document for Camera Models

    DEFF Research Database (Denmark)

    Thuesen, Gøsta

    1998-01-01

    Architecture of camera simulator models and data interface for the Maneuvering of Inspection/Servicing Vehicle (MIV) study.......Architecture of camera simulator models and data interface for the Maneuvering of Inspection/Servicing Vehicle (MIV) study....

  13. Selecting a digital camera for telemedicine.

    Science.gov (United States)

    Patricoski, Chris; Ferguson, A Stewart

    2009-06-01

    The digital camera is an essential component of store-and-forward telemedicine (electronic consultation). There are numerous makes and models of digital cameras on the market, and selecting a suitable consumer-grade camera can be complicated. Evaluation of digital cameras includes investigating the features and analyzing image quality. Important features include the camera settings, ease of use, macro capabilities, method of image transfer, and power recharging. Consideration needs to be given to image quality, especially as it relates to color (skin tones) and detail. It is important to know the level of the photographer and the intended application. The goal is to match the characteristics of the camera with the telemedicine program requirements. In the end, selecting a digital camera is a combination of qualitative (subjective) and quantitative (objective) analysis. For the telemedicine program in Alaska in 2008, the camera evaluation and decision process resulted in a specific selection based on the criteria developed for our environment.

  14. 21 CFR 886.1120 - Opthalmic camera.

    Science.gov (United States)

    2010-04-01

    ... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1120 Opthalmic camera. (a) Identification. An ophthalmic camera is an AC-powered device intended to take photographs of the eye and the surrounding area...

  15. Improved positron emission tomography camera

    International Nuclear Information System (INIS)

    Mullani, N.A.

    1986-01-01

    A positron emission tomography camera having a plurality of rings of detectors positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom, and a plurality of scintillation crystals positioned relative to the photomultiplier tubes whereby each tube is responsive to more than one crystal. Each alternate crystal in the ring may be offset by one-half or less of the thickness of the crystal such that the staggered crystals are seen by more than one photomultiplier tube. This sharing of crystals and photomultiplier tubes allows identification of the staggered crystal and the use of smaller detectors shared by larger photomultiplier tubes thereby requiring less photomultiplier tubes, creating more scanning slices, providing better data sampling, and reducing the cost of the camera. (author)

  16. Vehicular camera pedestrian detection research

    Science.gov (United States)

    Liu, Jiahui

    2018-03-01

    With the rapid development of science and technology, it has made great development, but at the same time of highway traffic more convenient in highway traffic and transportation. However, in the meantime, traffic safety accidents occur more and more frequently in China. In order to deal with the increasingly heavy traffic safety. So, protecting the safety of people's personal property and facilitating travel has become a top priority. The real-time accurate pedestrian and driving environment are obtained through a vehicular camera which are used to detection and track the preceding moving targets. It is popular in the domain of intelligent vehicle safety driving, autonomous navigation and traffic system research. Based on the pedestrian video obtained by the Vehicular Camera, this paper studies the trajectory of pedestrian detection and its algorithm.

  17. Graphic design of pinhole cameras

    Science.gov (United States)

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

    1979-01-01

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

  18. The MVACS Robotic Arm Camera

    Science.gov (United States)

    Keller, H. U.; Hartwig, H.; Kramm, R.; Koschny, D.; Markiewicz, W. J.; Thomas, N.; Fernades, M.; Smith, P. H.; Reynolds, R.; Lemmon, M. T.; Weinberg, J.; Marcialis, R.; Tanner, R.; Boss, B. J.; Oquest, C.; Paige, D. A.

    2001-08-01

    The Robotic Arm Camera (RAC) is one of the key instruments newly developed for the Mars Volatiles and Climate Surveyor payload of the Mars Polar Lander. This lightweight instrument employs a front lens with variable focus range and takes images at distances from 11 mm (image scale 1:1) to infinity. Color images with a resolution of better than 50 μm can be obtained to characterize the Martian soil. Spectral information of nearby objects is retrieved through illumination with blue, green, and red lamp sets. The design and performance of the camera are described in relation to the science objectives and operation. The RAC uses the same CCD detector array as the Surface Stereo Imager and shares the readout electronics with this camera. The RAC is mounted at the wrist of the Robotic Arm and can characterize the contents of the scoop, the samples of soil fed to the Thermal Evolved Gas Analyzer, the Martian surface in the vicinity of the lander, and the interior of trenches dug out by the Robotic Arm. It can also be used to take panoramic images and to retrieve stereo information with an effective baseline surpassing that of the Surface Stereo Imager by about a factor of 3.

  19. Coaxial fundus camera for opthalmology

    Science.gov (United States)

    de Matos, Luciana; Castro, Guilherme; Castro Neto, Jarbas C.

    2015-09-01

    A Fundus Camera for ophthalmology is a high definition device which needs to meet low light illumination of the human retina, high resolution in the retina and reflection free image1. Those constraints make its optical design very sophisticated, but the most difficult to comply with is the reflection free illumination and the final alignment due to the high number of non coaxial optical components in the system. Reflection of the illumination, both in the objective and at the cornea, mask image quality, and a poor alignment make the sophisticated optical design useless. In this work we developed a totally axial optical system for a non-midriatic Fundus Camera. The illumination is performed by a LED ring, coaxial with the optical system and composed of IR of visible LEDs. The illumination ring is projected by the objective lens in the cornea. The Objective, LED illuminator, CCD lens are coaxial making the final alignment easily to perform. The CCD + capture lens module is a CCTV camera with autofocus and Zoom built in, added to a 175 mm focal length doublet corrected for infinity, making the system easily operated and very compact.

  20. 16 CFR 501.1 - Camera film.

    Science.gov (United States)

    2010-01-01

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

  1. An Open Standard for Camera Trap Data

    NARCIS (Netherlands)

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

    2016-01-01

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

  2. A camera specification for tendering purposes

    International Nuclear Information System (INIS)

    Lunt, M.J.; Davies, M.D.; Kenyon, N.G.

    1985-01-01

    A standardized document is described which is suitable for sending to companies which are being invited to tender for the supply of a gamma camera. The document refers to various features of the camera, the performance specification of the camera, maintenance details, price quotations for various options and delivery, installation and warranty details. (U.K.)

  3. Continuous monitoring of Hawaiian volcanoes with thermal cameras

    Science.gov (United States)

    Patrick, Matthew R.; Orr, Tim R.; Antolik, Loren; Lee, Robert Lopaka; Kamibayashi, Kevan P.

    2014-01-01

    Continuously operating thermal cameras are becoming more common around the world for volcano monitoring, and offer distinct advantages over conventional visual webcams for observing volcanic activity. Thermal cameras can sometimes “see” through volcanic fume that obscures views to visual webcams and the naked eye, and often provide a much clearer view of the extent of high temperature areas and activity levels. We describe a thermal camera network recently installed by the Hawaiian Volcano Observatory to monitor Kīlauea’s summit and east rift zone eruptions (at Halema‘uma‘u and Pu‘u ‘Ō‘ō craters, respectively) and to keep watch on Mauna Loa’s summit caldera. The cameras are long-wave, temperature-calibrated models protected in custom enclosures, and often positioned on crater rims close to active vents. Images are transmitted back to the observatory in real-time, and numerous Matlab scripts manage the data and provide automated analyses and alarms. The cameras have greatly improved HVO’s observations of surface eruptive activity, which includes highly dynamic lava lake activity at Halema‘uma‘u, major disruptions to Pu‘u ‘Ō‘ō crater and several fissure eruptions.

  4. Transcriptional changes of rice in response to rice black-streaked dwarf virus.

    Science.gov (United States)

    Ahmed, Mohamed M S; Ji, Wen; Wang, Muyue; Bian, Shiquan; Xu, Meng; Wang, Weiyun; Zhang, Jiangxiang; Xu, Zhihao; Yu, Meimei; Liu, Qiaoquan; Zhang, Changquan; Zhang, Honggen; Tang, Shuzhu; Gu, Minghong; Yu, Hengxiu

    2017-09-10

    Rice black-streaked dwarf virus (RBSDV), a member of the genus Fijivirus in the family Reoviridae, causes significant economic losses in rice production in China and many other Asian countries. Although a great deal of effort has been made to elucidate the interactions among the virus, insect vectors, host and environmental conditions, few RBSDV proteins involved in pathogenesis have been identified, and the biological basis of disease development in rice remains largely unknown. Transcriptomic information associated with the disease development in rice would be helpful to unravel the biological mechanism. To determine how the rice transcriptome changes in response to RBSDV infection, we carried out RNA-Seq to perform a genome-wide gene expression analysis of a susceptible rice cultivar KTWYJ3. The transcriptomes of RBSDV-infected samples were compared to those of RBSDV-free (healthy) at two time points (time points are represented by group I and II). The results derived from the differential expression analysis in RBSDV-infected libraries vs. healthy ones in group I revealed that 102 out of a total of 281 significant differentially expressed genes (DEGs) were up-regulated and 179 DEGs were down-regulated. Of the 2592 identified DEGs in group II, 1588 DEGs were up-regulated and 1004 DEGs were down-regulated. A total of 66 DEGs were commonly identified in both groups. Of these 66 DEGs, expression patterns for 36 DEGs were similar in both groups. Our analysis demonstrated that some genes related to disease defense and stress resistance were up-regulated while genes associated with chloroplast were down-regulated in response to RBSDV infection. In addition, some genes associated with plant-height were differentially expressed. This result indicates those genes might be involved in dwarf symptoms caused by RBSDV. Taken together, our results provide a genome-wide transcriptome analysis for rice plants in response to RBSDV infection which may contribute to the

  5. Comparing the regional epidemiology of the cassava mosaic and cassava brown streak virus pandemics in Africa.

    Science.gov (United States)

    Legg, J P; Jeremiah, S C; Obiero, H M; Maruthi, M N; Ndyetabula, I; Okao-Okuja, G; Bouwmeester, H; Bigirimana, S; Tata-Hangy, W; Gashaka, G; Mkamilo, G; Alicai, T; Lava Kumar, P

    2011-08-01

    The rapid geographical expansion of the cassava mosaic disease (CMD) pandemic, caused by cassava mosaic geminiviruses, has devastated cassava crops in 12 countries of East and Central Africa since the late 1980s. Region-level surveys have revealed a continuing pattern of annual spread westward and southward along a contiguous 'front'. More recently, outbreaks of cassava brown streak disease (CBSD) were reported from Uganda and other parts of East Africa that had been hitherto unaffected by the disease. Recent survey data reveal several significant contrasts between the regional epidemiology of these two pandemics: (i) severe CMD radiates out from an initial centre of origin, whilst CBSD seems to be spreading from independent 'hot-spots'; (ii) the severe CMD pandemic has arisen from recombination and synergy between virus species, whilst the CBSD pandemic seems to be a 'new encounter' situation between host and pathogen; (iii) CMD pandemic spread has been tightly linked with the appearance of super-abundant Bemisia tabaci whitefly vector populations, in contrast to CBSD, where outbreaks have occurred 3-12 years after whitefly population increases; (iv) the CMGs causing CMD are transmitted in a persistent manner, whilst the two cassava brown streak viruses appear to be semi-persistently transmitted; and (v) different patterns of symptom expression mean that phytosanitary measures could be implemented easily for CMD but have limited effectiveness, whereas similar measures are difficult to apply for CBSD but are potentially very effective. An important similarity between the pandemics is that the viruses occurring in pandemic-affected areas are also found elsewhere, indicating that contrary to earlier published conclusions, the viruses per se are unlikely to be the key factors driving the two pandemics. A diagrammatic representation illustrates the temporal relationship between B. tabaci abundance and changing incidences of both CMD and CBSD in the Great Lakes region

  6. Mars Orbiter Camera Views the 'Face on Mars' - Comparison with Viking

    Science.gov (United States)

    1998-01-01

    processed to remove the sensitivity differences between adjacent picture elements (calibrated). This removes the vertical streaking. The contrast and brightness of the image was adjusted, and 'filters' were applied to enhance detail at several scales. The image was then geometrically warped to meet the computed position information for a mercator-type map. This corrected for the left-right flip, and the non-vertical viewing angle (about 45o from vertical), but also introduced some vertical 'elongation' of the image for the same reason Greenland looks larger than Africa on a mercator map of the Earth. A section of the image, containing the 'Face' and a couple of nearly impact craters and hills, was 'cut' out of the full image and reproduced separately.See PIA01440-1442 for additional processing steps. Also see PIA01236 for the raw image.Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  8. Stereo Pinhole Camera: Assembly and experimental activities

    Directory of Open Access Journals (Sweden)

    Gilmário Barbosa Santos

    2015-05-01

    Full Text Available This work describes the assembling of a stereo pinhole camera for capturing stereo-pairs of images and proposes experimental activities with it. A pinhole camera can be as sophisticated as you want, or so simple that it could be handcrafted with practically recyclable materials. This paper describes the practical use of the pinhole camera throughout history and currently. Aspects of optics and geometry involved in the building of the stereo pinhole camera are presented with illustrations. Furthermore, experiments are proposed by using the images obtained by the camera for 3D visualization through a pair of anaglyph glasses, and the estimation of relative depth by triangulation is discussed.

  9. Single Camera Calibration in 3D Vision

    Directory of Open Access Journals (Sweden)

    Caius SULIMAN

    2009-12-01

    Full Text Available Camera calibration is a necessary step in 3D vision in order to extract metric information from 2D images. A camera is considered to be calibrated when the parameters of the camera are known (i.e. principal distance, lens distorsion, focal length etc.. In this paper we deal with a single camera calibration method and with the help of this method we try to find the intrinsic and extrinsic camera parameters. The method was implemented with succes in the programming and simulation environment Matlab.

  10. Molecular insights into Cassava brown streak virus susceptibility and resistance by profiling of the early host response

    OpenAIRE

    Anjanappa, Ravi B; Mehta, Devang; Okoniewski, Michal J; Szabelska-Berȩsewicz, Alicja; Gruissem, Wilhelm; Vanderschuren, Hervé

    2018-01-01

    Cassava brown streak viruses (CBSVs) are responsible for significant cassava yield losses in eastern sub-Saharan Africa. To study the possible mechanisms of plant resistance to CBSVs we inoculated CBSV-susceptible and -resistant cassava varieties with a mixed infection of CBSVs using top-cleft grafting. Transcriptome profiling of the two cassava varieties was performed at the earliest time-point of full infection (28 days after grafting) in the susceptible scions. The expression of genes enco...

  11. Hubble Space Telescope, Faint Object Camera

    Science.gov (United States)

    1981-01-01

    This drawing illustrates Hubble Space Telescope's (HST's), Faint Object Camera (FOC). The FOC reflects light down one of two optical pathways. The light enters a detector after passing through filters or through devices that can block out light from bright objects. Light from bright objects is blocked out to enable the FOC to see background images. The detector intensifies the image, then records it much like a television camera. For faint objects, images can be built up over long exposure times. The total image is translated into digital data, transmitted to Earth, and then reconstructed. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors.

  12. Reconstruction in PET cameras with irregular sampling and depth of interaction capability

    International Nuclear Information System (INIS)

    Virador, P.R.G.; Moses, W.W.; Huesman, R.H.

    1998-01-01

    The authors present 2D reconstruction algorithms for a rectangular PET camera capable of measuring depth of interaction (DOI). The camera geometry leads to irregular radial and angular sampling of the tomographic data. DOI information increases sampling density, allowing the use of evenly spaced quarter-crystal width radial bins with minimal interpolation of irregularly spaced data. In the regions where DOI does not increase sampling density (chords normal to crystal faces), fine radial sinogram binning leads to zero efficiency bins if uniform angular binning is used. These zero efficiency sinogram bins lead to streak artifacts if not corrected. To minimize these unnormalizable sinogram bins the authors use two angular binning schemes: Fixed Width and Natural Width. Fixed Width uses a fixed angular width except in the problem regions where appropriately chosen widths are applied. Natural Width uses angle widths which are derived from intrinsic detector sampling. Using a modified filtered-backprojection algorithm to accommodate these angular binning schemes, the authors reconstruct artifact free images with nearly isotropic and position independent spatial resolution. Results from Monte Carlo data indicate that they have nearly eliminated image degradation due to crystal penetration

  13. Meteor Film Recording with Digital Film Cameras with large CMOS Sensors

    Science.gov (United States)

    Slansky, P. C.

    2016-12-01

    In this article the author combines his professional know-how about cameras for film and television production with his amateur astronomy activities. Professional digital film cameras with high sensitivity are still quite rare in astronomy. One reason for this may be their costs of up to 20 000 and more (camera body only). In the interim, however,consumer photo cameras with film mode and very high sensitivity have come to the market for about 2 000 EUR. In addition, ultra-high sensitive professional film cameras, that are very interesting for meteor observation, have been introduced to the market. The particular benefits of digital film cameras with large CMOS sensors, including photo cameras with film recording function, for meteor recording are presented by three examples: a 2014 Camelopardalid, shot with a Canon EOS C 300, an exploding 2014 Aurigid, shot with a Sony alpha7S, and the 2016 Perseids, shot with a Canon ME20F-SH. All three cameras use large CMOS sensors; "large" meaning Super-35 mm, the classic 35 mm film format (24x13.5 mm, similar to APS-C size), or full format (36x24 mm), the classic 135 photo camera format. Comparisons are made to the widely used cameras with small CCD sensors, such as Mintron or Watec; "small" meaning 12" (6.4x4.8 mm) or less. Additionally, special photographic image processing of meteor film recordings is discussed.

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

    Directory of Open Access Journals (Sweden)

    Nina Dragičević

    2015-09-01

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

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

    Directory of Open Access Journals (Sweden)

    E. R. Al-Kennany

    2010-01-01

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

  16. Drivers Behind Adoption Of Cassava Brown Streak Disease Control Measures In Rwanda

    Directory of Open Access Journals (Sweden)

    Nyirahorana

    2017-11-01

    Full Text Available Cassava Brown Streak Disease CBSD continues to spread and its effect on productivity remains at high level losses 50- 100 in Sub-Saharan Africa. However there is little knowledge about the drivers of adoption on CBSD control measures in Rwanda. Thus this study investigated the drivers to adopt CBSD control measures in Rwanda during 2015-2016 agricultural seasons. A total of 152 households were randomly sampled in Bugesera and Ruhango districts where cassava demonstration plots are established. A multi stage sampling techniques was used. A structured questionnaire was used to collect data from respondents. Logistic regression analysis was employed to estimate drivers behind adoption of CBSD control measures. The key factors that influenced adoption of CBSD control measures was farm size farmers experience access to credit period of plantation access to demonstration plot. In order to increase adoption of CBSD control measures policy makers and implementers in Rwanda should improve farmers social economic and Insistutional characteristics sensitize and mobilize farmers on the importance of adopting the CBSD control measures.

  17. Research on the underwater target imaging based on the streak tube laser lidar

    Science.gov (United States)

    Cui, Zihao; Tian, Zhaoshuo; Zhang, Yanchao; Bi, Zongjie; Yang, Gang; Gu, Erdan

    2018-03-01

    A high frame rate streak tube imaging lidar (STIL) for real-time 3D imaging of underwater targets is presented in this paper. The system uses 532nm pulse laser as the light source, the maximum repetition rate is 120Hz, and the pulse width is 8ns. LabVIEW platform is used in the system, the system control, synchronous image acquisition, 3D data processing and display are realized through PC. 3D imaging experiment of underwater target is carried out in a flume with attenuation coefficient of 0.2, and the images of different depth and different material targets are obtained, the imaging frame rate is 100Hz, and the maximum detection depth is 31m. For an underwater target with a distance of 22m, the high resolution 3D image real-time acquisition is realized with range resolution of 1cm and space resolution of 0.3cm, the spatial relationship of the targets can be clearly identified by the image. The experimental results show that STIL has a good application prospect in underwater terrain detection, underwater search and rescue, and other fields.

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

    Directory of Open Access Journals (Sweden)

    Fangquan Wang

    2016-05-01

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

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

    Science.gov (United States)

    Wang, Fangquan; Li, Wenqi; Zhu, Jinyan; Fan, Fangjun; Wang, Jun; Zhong, Weigong; Wang, Ming-Bo; Liu, Qing; Zhu, Qian-Hao; Zhou, Tong; Lan, Ying; Zhou, Yijun; Yang, Jie

    2016-05-11

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

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

    Directory of Open Access Journals (Sweden)

    Ahmed Raza

    2017-02-01

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

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

    Science.gov (United States)

    Raza, Ahmed; Al-Shahwan, Ibrahim M; Abdalla, Omer A; Al-Saleh, Mohammed A; Amer, Mahmoud A

    2017-02-01

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

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

    Science.gov (United States)

    Dong, J; Hayakawa, Y; Kober, C

    2014-01-01

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

  3. A compact low cost “master–slave” double crystal monochromator for x-ray cameras calibration of the Laser MégaJoule Facility

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, S., E-mail: sebastien.hubert@cea.fr; Prévot, V.

    2014-12-21

    The Alternative Energies and Atomic Energy Commission (CEA-CESTA, France) built a specific double crystal monochromator (DCM) to perform calibration of x-ray cameras (CCD, streak and gated cameras) by means of a multiple anode diode type x-ray source for the MégaJoule Laser Facility. This DCM, based on pantograph geometry, was specifically modeled to respond to relevant engineering constraints and requirements. The major benefits are mechanical drive of the second crystal on the first one, through a single drive motor, as well as compactness of the entire device. Designed for flat beryl or Ge crystals, this DCM covers the 0.9–10 keV range of our High Energy X-ray Source. In this paper we present the mechanical design of the DCM, its features quantitatively measured and its calibration to finally provide monochromatized spectra displaying spectral purities better than 98%.

  4. Collimator changer for scintillation camera

    International Nuclear Information System (INIS)

    Jupa, E.C.; Meeder, R.L.; Richter, E.K.

    1976-01-01

    A collimator changing assembly mounted on the support structure of a scintillation camera is described. A vertical support column positioned proximate the detector support column with a plurality of support arms mounted thereon in a rotatable cantilevered manner at separate vertical positions. Each support arm is adapted to carry one of the plurality of collimators which are interchangeably mountable on the underside of the detector and to transport the collimator between a store position remote from the detector and a change position underneath said detector

  5. Robot Tracer with Visual Camera

    Science.gov (United States)

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

    2017-12-01

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

  6. Radiometric calibration of digital cameras using neural networks

    Science.gov (United States)

    Grunwald, Michael; Laube, Pascal; Schall, Martin; Umlauf, Georg; Franz, Matthias O.

    2017-08-01

    Digital cameras are used in a large variety of scientific and industrial applications. For most applications, the acquired data should represent the real light intensity per pixel as accurately as possible. However, digital cameras are subject to physical, electronic and optical effects that lead to errors and noise in the raw image. Temperature- dependent dark current, read noise, optical vignetting or different sensitivities of individual pixels are examples of such effects. The purpose of radiometric calibration is to improve the quality of the resulting images by reducing the influence of the various types of errors on the measured data and thus improving the quality of the overall application. In this context, we present a specialized neural network architecture for radiometric calibration of digital cameras. Neural networks are used to learn a temperature- and exposure-dependent mapping from observed gray-scale values to true light intensities for each pixel. In contrast to classical at-fielding, neural networks have the potential to model nonlinear mappings which allows for accurately capturing the temperature dependence of the dark current and for modeling cameras with nonlinear sensitivities. Both scenarios are highly relevant in industrial applications. The experimental comparison of our network approach to classical at-fielding shows a consistently higher reconstruction quality, also for linear cameras. In addition, the calibration is faster than previous machine learning approaches based on Gaussian processes.

  7. A mathematical model for camera calibration based on straight lines

    Directory of Open Access Journals (Sweden)

    Antonio M. G. Tommaselli

    2005-12-01

    Full Text Available In other to facilitate the automation of camera calibration process, a mathematical model using straight lines was developed, which is based on the equivalent planes mathematical model. Parameter estimation of the developed model is achieved by the Least Squares Method with Conditions and Observations. The same method of adjustment was used to implement camera calibration with bundles, which is based on points. Experiments using simulated and real data have shown that the developed model based on straight lines gives results comparable to the conventional method with points. Details concerning the mathematical development of the model and experiments with simulated and real data will be presented and the results with both methods of camera calibration, with straight lines and with points, will be compared.

  8. Impact of New Camera Technologies on Discoveries in Cell Biology.

    Science.gov (United States)

    Stuurman, Nico; Vale, Ronald D

    2016-08-01

    New technologies can make previously invisible phenomena visible. Nowhere is this more obvious than in the field of light microscopy. Beginning with the observation of "animalcules" by Antonie van Leeuwenhoek, when he figured out how to achieve high magnification by shaping lenses, microscopy has advanced to this day by a continued march of discoveries driven by technical innovations. Recent advances in single-molecule-based technologies have achieved unprecedented resolution, and were the basis of the Nobel prize in Chemistry in 2014. In this article, we focus on developments in camera technologies and associated image processing that have been a major driver of technical innovations in light microscopy. We describe five types of developments in camera technology: video-based analog contrast enhancement, charge-coupled devices (CCDs), intensified sensors, electron multiplying gain, and scientific complementary metal-oxide-semiconductor cameras, which, together, have had major impacts in light microscopy. © 2016 Marine Biological Laboratory.

  9. Automated Meteor Detection by All-Sky Digital Camera Systems

    Science.gov (United States)

    Suk, Tomáš; Šimberová, Stanislava

    2017-12-01

    We have developed a set of methods to detect meteor light traces captured by all-sky CCD cameras. Operating at small automatic observatories (stations), these cameras create a network spread over a large territory. Image data coming from these stations are merged in one central node. Since a vast amount of data is collected by the stations in a single night, robotic storage and analysis are essential to processing. The proposed methodology is adapted to data from a network of automatic stations equipped with digital fish-eye cameras and includes data capturing, preparation, pre-processing, analysis, and finally recognition of objects in time sequences. In our experiments we utilized real observed data from two stations.

  10. Realistic camera noise modeling with application to improved HDR synthesis

    Science.gov (United States)

    Goossens, Bart; Luong, Hiêp; Aelterman, Jan; Pižurica, Aleksandra; Philips, Wilfried

    2012-12-01

    Due to the ongoing miniaturization of digital camera sensors and the steady increase of the "number of megapixels", individual sensor elements of the camera become more sensitive to noise, even deteriorating the final image quality. To go around this problem, sophisticated processing algorithms in the devices, can help to maximally exploit the knowledge on the sensor characteristics (e.g., in terms of noise), and offer a better image reconstruction. Although a lot of research focuses on rather simplistic noise models, such as stationary additive white Gaussian noise, only limited attention has gone to more realistic digital camera noise models. In this article, we first present a digital camera noise model that takes several processing steps in the camera into account, such as sensor signal amplification, clipping, post-processing,.. We then apply this noise model to the reconstruction problem of high dynamic range (HDR) images from a small set of low dynamic range (LDR) exposures of a static scene. In literature, HDR reconstruction is mostly performed by computing a weighted average, in which the weights are directly related to the observer pixel intensities of the LDR image. In this work, we derive a Bayesian probabilistic formulation of a weighting function that is near-optimal in the MSE sense (or SNR sense) of the reconstructed HDR image, by assuming exponentially distributed irradiance values. We define the weighting function as the probability that the observed pixel intensity is approximately unbiased. The weighting function can be directly computed based on the noise model parameters, which gives rise to different symmetric and asymmetric shapes when electronic noise or photon noise is dominant. We also explain how to deal with the case that some of the noise model parameters are unknown and explain how the camera response function can be estimated using the presented noise model. Finally, experimental results are provided to support our findings.

  11. Using DSLR cameras in digital holography

    Science.gov (United States)

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

    2017-08-01

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

  12. Human tracking over camera networks: a review

    Science.gov (United States)

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

    2017-12-01

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

  13. Image compensation for camera and lighting variability

    Science.gov (United States)

    Daley, Wayne D.; Britton, Douglas F.

    1996-12-01

    With the current trend of integrating machine vision systems in industrial manufacturing and inspection applications comes the issue of camera and illumination stabilization. Unless each application is built around a particular camera and highly controlled lighting environment, the interchangeability of cameras of fluctuations in lighting become a problem as each camera usually has a different response. An empirical approach is proposed where color tile data is acquired using the camera of interest, and a mapping is developed to some predetermined reference image using neural networks. A similar analytical approach based on a rough analysis of the imaging systems is also considered for deriving a mapping between cameras. Once a mapping has been determined, all data from one camera is mapped to correspond to the images of the other prior to performing any processing on the data. Instead of writing separate image processing algorithms for the particular image data being received, the image data is adjusted based on each particular camera and lighting situation. All that is required when swapping cameras is the new mapping for the camera being inserted. The image processing algorithms can remain the same as the input data has been adjusted appropriately. The results of utilizing this technique are presented for an inspection application.

  14. Optimising camera traps for monitoring small mammals.

    Directory of Open Access Journals (Sweden)

    Alistair S Glen

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

  15. The upgrade of the H.E.S.S. cameras

    Science.gov (United States)

    Giavitto, Gianluca; Ashton, Terry; Balzer, Arnim; Berge, David; Brun, Francois; Chaminade, Thomas; Delagnes, Eric; Fontaine, Gerard; Füßling, Matthias; Giebels, Berrie; Glicenstein, Jean-Francois; Gräber, Tobias; Hinton, Jim; Jahnke, Albert; Klepser, Stefan; Kossatz, Marko; Kretzschmann, Axel; Lefranc, Valentin; Leich, Holger; Lüdecke, Hartmut; Lypova, Iryna; Manigot, Pascal; Marandon, Vincent; Moulin, Emmanuel; Naurois, Mathieu de; Nayman, Patrick; Ohm, Stefan; Penno, Marek; Ross, Duncan; Salek, David; Schade, Markus; Schwab, Thomas; Simoni, Rachel; Stegmann, Christian; Steppa, Constantin; Thornhill, Julian; Toussnel, Francois

    2017-12-01

    The High Energy Stereoscopic System (HESS) is an array of imaging atmospheric Cherenkov telescopes (IACTs) located in the Khomas highland in Namibia. It was built to detect Very High Energy (VHE > 100 GeV) cosmic gamma rays. Since 2003, HESS has discovered the majority of the known astrophysical VHE gamma-ray sources, opening a new observational window on the extreme non-thermal processes at work in our universe. HESS consists of four 12-m diameter Cherenkov telescopes (CT1-4), which started data taking in 2002, and a larger 28-m telescope (CT5), built in 2012, which lowers the energy threshold of the array to 30 GeV . The cameras of CT1-4 are currently undergoing an extensive upgrade, with the goals of reducing their failure rate, reducing their readout dead time and improving the overall performance of the array. The entire camera electronics has been renewed from ground-up, as well as the power, ventilation and pneumatics systems, and the control and data acquisition software. Only the PMTs and their HV supplies have been kept from the original cameras. Novel technical solutions have been introduced, which will find their way into some of the Cherenkov cameras foreseen for the next-generation Cherenkov Telescope Array (CTA) observatory. In particular, the camera readout system is the first large-scale system based on the analog memory chip NECTAr, which was designed for CTA cameras. The camera control subsystems and the control software framework also pursue an innovative design, exploiting cutting-edge hardware and software solutions which excel in performance, robustness and flexibility. The CT1 camera has been upgraded in July 2015 and is currently taking data; CT2-4 have been upgraded in fall 2016. Together they will assure continuous operation of HESS at its full sensitivity until and possibly beyond the advent of CTA. This contribution describes the design, the testing and the in-lab and on-site performance of all components of the newly upgraded HESS

  16. RNAi-mediated resistance to rice black-streaked dwarf virus in transgenic rice.

    Science.gov (United States)

    Ahmed, Mohamed M S; Bian, Shiquan; Wang, Muyue; Zhao, Jing; Zhang, Bingwei; Liu, Qiaoquan; Zhang, Changquan; Tang, Shuzhu; Gu, Minghong; Yu, Hengxiu

    2017-04-01

    Rice black-streaked dwarf virus (RBSDV), a member of the genus Fijivirus in the family Reoviridae, causes significant economic losses in rice production in China and many other Asian countries. Development of resistant varieties by using conventional breeding methods is limited, as germplasm with high level of resistance to RBSDV have not yet been found. One of the most promising methods to confer resistance against RBSDV is the use of RNA interference (RNAi) technology. RBSDV non-structural protein P7-2, encoded by S7-2 gene, is a potential F-box protein and involved in the plant-virus interaction through the ubiquitination pathway. P8, encoded by S8 gene, is the minor core protein that possesses potent active transcriptional repression activity. In this study, we transformed rice calli using a mini-twin T-DNA vector harboring RNAi constructs of the RBSDV genes S7-2 or S8, and obtained plants harboring the target gene constructs and the selectable marker gene, hygromycin phosphotransferase (HPT). From the offspring of these transgenic plants, we obtained selectable marker (HPT gene)-free plants. Homozygous T 5 transgenic lines which harbored either S7-2-RNAi or S8-RNAi exhibited high level resistance against RBSDV under field infection pressure from indigenous viruliferous small brown planthoppers. Thus, our results showed that RNA interference with the expression of S7-2 or S8 genes seemed an effective way to induce high level resistance in rice against RBSD disease.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-11-02

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

  19. Bring your own camera to the trap: An inexpensive, versatile, and portable triggering system tested on wild hummingbirds.

    Science.gov (United States)

    Rico-Guevara, Alejandro; Mickley, James

    2017-07-01

    The study of animals in the wild offers opportunities to collect relevant information on their natural behavior and abilities to perform ecologically relevant tasks. However, it also poses challenges such as accounting for observer effects, human sensory limitations, and the time intensiveness of this type of research. To meet these challenges, field biologists have deployed camera traps to remotely record animal behavior in the wild. Despite their ubiquity in research, many commercial camera traps have limitations, and the species and behavior of interest may present unique challenges. For example, no camera traps support high-speed video recording. We present a new and inexpensive camera trap system that increases versatility by separating the camera from the triggering mechanism. Our system design can pair with virtually any camera and allows for independent positioning of a variety of sensors, all while being low-cost, lightweight, weatherproof, and energy efficient. By using our specialized trigger and customized sensor configurations, many limitations of commercial camera traps can be overcome. We use this system to study hummingbird feeding behavior using high-speed video cameras to capture fast movements and multiple sensors placed away from the camera to detect small body sizes. While designed for hummingbirds, our application can be extended to any system where specialized camera or sensor features are required, or commercial camera traps are cost-prohibitive, allowing camera trap use in more research avenues and by more researchers.

  20. Photogrammetric Applications of Immersive Video Cameras

    OpenAIRE

    Kwiatek, K.; Tokarczyk, R.

    2014-01-01

    The paper investigates immersive videography and its application in close-range photogrammetry. Immersive video involves the capture of a live-action scene that presents a 360° field of view. It is recorded simultaneously by multiple cameras or microlenses, where the principal point of each camera is offset from the rotating axis of the device. This issue causes problems when stitching together individual frames of video separated from particular cameras, however there are ways to ov...

  1. Movement-based Interaction in Camera Spaces

    DEFF Research Database (Denmark)

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

    2006-01-01

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

  2. Performance analysis for gait in camera networks

    OpenAIRE

    Michela Goffredo; Imed Bouchrika; John Carter; Mark Nixon

    2008-01-01

    This paper deploys gait analysis for subject identification in multi-camera surveillance scenarios. We present a new method for viewpoint independent markerless gait analysis that does not require camera calibration and works with a wide range of directions of walking. These properties make the proposed method particularly suitable for gait identification in real surveillance scenarios where people and their behaviour need to be tracked across a set of cameras. Tests on 300 synthetic and real...

  3. Camera processing with chromatic aberration.

    Science.gov (United States)

    Korneliussen, Jan Tore; Hirakawa, Keigo

    2014-10-01

    Since the refractive index of materials commonly used for lens depends on the wavelengths of light, practical camera optics fail to converge light to a single point on an image plane. Known as chromatic aberration, this phenomenon distorts image details by introducing magnification error, defocus blur, and color fringes. Though achromatic and apochromatic lens designs reduce chromatic aberration to a degree, they are complex and expensive and they do not offer a perfect correction. In this paper, we propose a new postcapture processing scheme designed to overcome these problems computationally. Specifically, the proposed solution is comprised of chromatic aberration-tolerant demosaicking algorithm and post-demosaicking chromatic aberration correction. Experiments with simulated and real sensor data verify that the chromatic aberration is effectively corrected.

  4. Approximations to camera sensor noise

    Science.gov (United States)

    Jin, Xiaodan; Hirakawa, Keigo

    2013-02-01

    Noise is present in all image sensor data. Poisson distribution is said to model the stochastic nature of the photon arrival process, while it is common to approximate readout/thermal noise by additive white Gaussian noise (AWGN). Other sources of signal-dependent noise such as Fano and quantization also contribute to the overall noise profile. Question remains, however, about how best to model the combined sensor noise. Though additive Gaussian noise with signal-dependent noise variance (SD-AWGN) and Poisson corruption are two widely used models to approximate the actual sensor noise distribution, the justification given to these types of models are based on limited evidence. The goal of this paper is to provide a more comprehensive characterization of random noise. We concluded by presenting concrete evidence that Poisson model is a better approximation to real camera model than SD-AWGN. We suggest further modification to Poisson that may improve the noise model.

  5. Comparative evaluation of consumer grade cameras and mobile phone cameras for close range photogrammetry

    Science.gov (United States)

    Chikatsu, Hirofumi; Takahashi, Yoji

    2009-08-01

    The authors have been concentrating on developing convenient 3D measurement methods using consumer grade digital cameras, and it was concluded that consumer grade digital cameras are expected to become a useful photogrammetric device for the various close range application fields. On the other hand, mobile phone cameras which have 10 mega pixels were appeared on the market in Japan. In these circumstances, we are faced with alternative epoch-making problem whether mobile phone cameras are able to take the place of consumer grade digital cameras in close range photogrammetric applications. In order to evaluate potentials of mobile phone cameras in close range photogrammetry, comparative evaluation between mobile phone cameras and consumer grade digital cameras are investigated in this paper with respect to lens distortion, reliability, stability and robustness. The calibration tests for 16 mobile phone cameras and 50 consumer grade digital cameras were conducted indoors using test target. Furthermore, practability of mobile phone camera for close range photogrammetry was evaluated outdoors. This paper presents that mobile phone cameras have ability to take the place of consumer grade digital cameras, and develop the market in digital photogrammetric fields.

  6. Decision about buying a gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Ganatra, R D

    1993-12-31

    A large part of the referral to a nuclear medicine department is usually for imaging studies. Sooner or later, the nuclear medicine specialist will be called upon to make a decision about when and what type of gamma camera to buy. There is no longer an option of choosing between a rectilinear scanner and a gamma camera as the former is virtually out of the market. The decision that one has to make is when to invest in a gamma camera, and then on what basis to select the gamma camera 1 tab., 1 fig

  7. Object tracking using multiple camera video streams

    Science.gov (United States)

    Mehrubeoglu, Mehrube; Rojas, Diego; McLauchlan, Lifford

    2010-05-01

    Two synchronized cameras are utilized to obtain independent video streams to detect moving objects from two different viewing angles. The video frames are directly correlated in time. Moving objects in image frames from the two cameras are identified and tagged for tracking. One advantage of such a system involves overcoming effects of occlusions that could result in an object in partial or full view in one camera, when the same object is fully visible in another camera. Object registration is achieved by determining the location of common features in the moving object across simultaneous frames. Perspective differences are adjusted. Combining information from images from multiple cameras increases robustness of the tracking process. Motion tracking is achieved by determining anomalies caused by the objects' movement across frames in time in each and the combined video information. The path of each object is determined heuristically. Accuracy of detection is dependent on the speed of the object as well as variations in direction of motion. Fast cameras increase accuracy but limit the speed and complexity of the algorithm. Such an imaging system has applications in traffic analysis, surveillance and security, as well as object modeling from multi-view images. The system can easily be expanded by increasing the number of cameras such that there is an overlap between the scenes from at least two cameras in proximity. An object can then be tracked long distances or across multiple cameras continuously, applicable, for example, in wireless sensor networks for surveillance or navigation.

  8. Scintillation camera for high activity sources

    International Nuclear Information System (INIS)

    Arseneau, R.E.

    1978-01-01

    The invention described relates to a scintillation camera used for clinical medical diagnosis. Advanced recognition of many unacceptable pulses allows the scintillation camera to discard such pulses at an early stage in processing. This frees the camera to process a greater number of pulses of interest within a given period of time. Temporary buffer storage allows the camera to accommodate pulses received at a rate in excess of its maximum rated capability due to statistical fluctuations in the level of radioactivity of the radiation source measured. (U.K.)

  9. Decision about buying a gamma camera

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    A large part of the referral to a nuclear medicine department is usually for imaging studies. Sooner or later, the nuclear medicine specialist will be called upon to make a decision about when and what type of gamma camera to buy. There is no longer an option of choosing between a rectilinear scanner and a gamma camera as the former is virtually out of the market. The decision that one has to make is when to invest in a gamma camera, and then on what basis to select the gamma camera

  10. Engineering task plan for flammable gas atmosphere mobile color video camera systems

    International Nuclear Information System (INIS)

    Kohlman, E.H.

    1995-01-01

    This Engineering Task Plan (ETP) describes the design, fabrication, assembly, and testing of the mobile video camera systems. The color video camera systems will be used to observe and record the activities within the vapor space of a tank on a limited exposure basis. The units will be fully mobile and designed for operation in the single-shell flammable gas producing tanks. The objective of this tank is to provide two mobile camera systems for use in flammable gas producing single-shell tanks (SSTs) for the Flammable Gas Tank Safety Program. The camera systems will provide observation, video recording, and monitoring of the activities that occur in the vapor space of applied tanks. The camera systems will be designed to be totally mobile, capable of deployment up to 6.1 meters into a 4 inch (minimum) riser

  11. Visual Positioning Indoors: Human Eyes vs. Smartphone Cameras.

    Science.gov (United States)

    Wu, Dewen; Chen, Ruizhi; Chen, Liang

    2017-11-16

    Artificial Intelligence (AI) technologies and their related applications are now developing at a rapid pace. Indoor positioning will be one of the core technologies that enable AI applications because people spend 80% of their time indoors. Humans can locate themselves related to a visually well-defined object, e.g., a door, based on their visual observations. Can a smartphone camera do a similar job when it points to an object? In this paper, a visual positioning solution was developed based on a single image captured from a smartphone camera pointing to a well-defined object. The smartphone camera simulates the process of human eyes for the purpose of relatively locating themselves against a well-defined object. Extensive experiments were conducted with five types of smartphones on three different indoor settings, including a meeting room, a library, and a reading room. Experimental results shown that the average positioning accuracy of the solution based on five smartphone cameras is 30.6 cm, while that for the human-observed solution with 300 samples from 10 different people is 73.1 cm.

  12. COMPARISON OF METHODS FOR GEOMETRIC CAMERA CALIBRATION

    Directory of Open Access Journals (Sweden)

    J. Hieronymus

    2012-09-01

    Full Text Available Methods for geometric calibration of cameras in close-range photogrammetry are established and well investigated. The most common one is based on test-fields with well-known pattern, which are observed from different directions. The parameters of a distortion model are calculated using bundle-block-adjustment-algorithms. This methods works well for short focal lengths, but is essentially more problematic to use with large focal lengths. Those would require very large test-fields and surrounding space. To overcome this problem, there is another common method for calibration used in remote sensing. It employs measurements using collimator and a goniometer. A third calibration method uses diffractive optical elements (DOE to project holograms of well known pattern. In this paper these three calibration methods are compared empirically, especially in terms of accuracy. A camera has been calibrated with those methods mentioned above. All methods provide a set of distortion correction parameters as used by the photogrammetric software Australis. The resulting parameter values are very similar for all investigated methods. The three sets of distortion parameters are crosscompared against all three calibration methods. This is achieved by inserting the gained distortion parameters as fixed input into the calibration algorithms and only adjusting the exterior orientation. The RMS (root mean square of the remaining image coordinate residuals are taken as a measure of distortion correction quality. There are differences resulting from the different calibration methods. Nevertheless the measure is small for every comparison, which means that all three calibration methods can be used for accurate geometric calibration.

  13. Assessment of reference gene stability in Rice stripe virus and Rice black streaked dwarf virus infection rice by quantitative Real-time PCR.

    Science.gov (United States)

    Fang, Peng; Lu, Rongfei; Sun, Feng; Lan, Ying; Shen, Wenbiao; Du, Linlin; Zhou, Yijun; Zhou, Tong

    2015-10-24

    Stably expressed reference gene(s) normalization is important for the understanding of gene expression patterns by quantitative Real-time PCR (RT-qPCR), particularly for Rice stripe virus (RSV) and Rice black streaked dwarf virus (RBSDV) that caused seriously damage on rice plants in China and Southeast Asia. The expression of fourteen common used reference genes of Oryza sativa L. were evaluated by RT-qPCR in RSV and RBSDV infected rice plants. Suitable normalization reference gene(s) were identified by geNorm and NormFinder algorithms. UBQ 10 + GAPDH and UBC + Actin1 were identified as suitable reference genes for RT-qPCR normalization under RSV and RBSDV infection, respectively. When using multiple reference genes, the expression patterns of OsPRIb and OsWRKY, two virus resistance genes, were approximately similar with that reported previously. Comparatively, by using single reference gene (TIP41-Like), a weaker inducible response was observed. We proposed that the combination of two reference genes could obtain more accurate and reliable normalization of RT-qPCR results in RSV- and RBSDV-infected plants. This work therefore sheds light on establishing a standardized RT-qPCR procedure in RSV- and RBSDV-infected rice plants, and might serve as an important point for discovering complex regulatory networks and identifying genes relevant to biological processes or implicated in virus.

  14. The diagnostic value and histologic correlate of distinct patterns of shiny white streaks for the diagnosis of melanoma: A retrospective, case-control study.

    Science.gov (United States)

    Verzi, Anna Eliza; Quan, Victor L; Walton, Kara E; Martini, Mary C; Marghoob, Ashfaq A; Garfield, Erin M; Kong, Betty Y; Isales, Maria Cristina; VandenBoom, Timothy; Zhang, Bin; West, Dennis P; Gerami, Pedram

    2018-05-01

    Shiny white streaks (SWSs) are best visualized with polarized dermoscopy and correlate with dermal fibroplasia histopathologically. SWSs have been described at higher frequencies in melanomas than in benign nevi. We assessed the diagnostic value of different patterns of SWSs and their histologic correlate in melanocytic lesions. Polarized dermoscopic images of 1507 histopathologically diagnosed melanocytic neoplasms were analyzed for presence and pattern of SWSs. Histology was also reviewed for correlation. Among 1507 melanocytic neoplasms, SWSs were observed in 31 of 144 melanomas (22%) and 22 of 1363 benign neoplasms (1.6%) (P < .001). The sensitivity and specificity of SWSs for melanoma were 22% and 98%, respectively. Diffuse SWSs exhibited the greatest diagnostic value for melanoma, with sensitivity of 11.8% and specificity of 99.5%. Focal central and peripheral SWSs were comparable in diagnostic significance. The presence of SWSs was highly uncommon in dysplastic nevi, whereas in certain benign subgroups of nevi such as Spitz nevi and atypical genital special site nevi, SWSs were not uncommon. Diffuse SWSs correlated with greater breadth of deep fibroplasia than focal SWSs (P = .009), and SWSs correlated with greater Breslow depth among melanomas (P = .007). This study was retrospective. Polarized dermoscopy is a valuable diagnostic tool in the identification of SWSs, a feature that is highly specific for melanoma. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  15. An alternative scanning protocol to eliminate perivenous streak artifacts in thoracic spiral computed tomography. The usefulness of ankle vein contrast injection

    International Nuclear Information System (INIS)

    Hara, Masaki; Ogino, Hiroyuki; Itoh, Masato; Ohba, Satoru; Andoh, Keiichi; Kitase, Masanori; Goodman, P.C.

    2001-01-01

    The purpose of this study was to eliminate perivenous streak artifact from contrast-enhanced thoracic spiral CT using superficial ankle vein injection (ankle vein method). Forty-four consecutive inpatients had thoracic spiral CT following ankle vein method and were compared to 30 patients who had conventional antecubital vein injection. Non-ionic 300 mg/mL contrast material were injected at 1-1.5 mL/sec with a power injector. Twenty mL of normal saline was injected immediately thereafter as a flushing bolus. Qualitative scores of perivenous artifact (1 to 5=extensive) and vascular enhancement (1 to 5=excellent) were recorded. Complications were investigated clinically. The mean score of perivenous artifact was 1 with the ankle vein method and 4.4 with the conventional method (P<.0001). Scores of pulmonary artery opacification were almost equal (4.2 and 4.5 respectively, P=.11). No complications were observed. The ankle vein method is an effective method to prevent perivenous artifact during thoracic spiral CT. (author)

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

    NARCIS (Netherlands)

    Kooi, F.L.; Zeeders, R.

    2009-01-01

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

  17. Automatic inference of geometric camera parameters and intercamera topology in uncalibrated disjoint surveillance cameras

    NARCIS (Netherlands)

    Hollander, R.J.M. den; Bouma, H.; Baan, J.; Eendebak, P.T.; Rest, J.H.C. van

    2015-01-01

    Person tracking across non-overlapping cameras and other types of video analytics benefit from spatial calibration information that allows an estimation of the distance between cameras and a relation between pixel coordinates and world coordinates within a camera. In a large environment with many

  18. Web Camera Based Eye Tracking to Assess Visual Memory on a Visual Paired Comparison Task

    Directory of Open Access Journals (Sweden)

    Nicholas T. Bott

    2017-06-01

    Full Text Available Background: Web cameras are increasingly part of the standard hardware of most smart devices. Eye movements can often provide a noninvasive “window on the brain,” and the recording of eye movements using web cameras is a burgeoning area of research.Objective: This study investigated a novel methodology for administering a visual paired comparison (VPC decisional task using a web camera.To further assess this method, we examined the correlation between a standard eye-tracking camera automated scoring procedure [obtaining images at 60 frames per second (FPS] and a manually scored procedure using a built-in laptop web camera (obtaining images at 3 FPS.Methods: This was an observational study of 54 clinically normal older adults.Subjects completed three in-clinic visits with simultaneous recording of eye movements on a VPC decision task by a standard eye tracker camera and a built-in laptop-based web camera. Inter-rater reliability was analyzed using Siegel and Castellan's kappa formula. Pearson correlations were used to investigate the correlation between VPC performance using a standard eye tracker camera and a built-in web camera.Results: Strong associations were observed on VPC mean novelty preference score between the 60 FPS eye tracker and 3 FPS built-in web camera at each of the three visits (r = 0.88–0.92. Inter-rater agreement of web camera scoring at each time point was high (κ = 0.81–0.88. There were strong relationships on VPC mean novelty preference score between 10, 5, and 3 FPS training sets (r = 0.88–0.94. Significantly fewer data quality issues were encountered using the built-in web camera.Conclusions: Human scoring of a VPC decisional task using a built-in laptop web camera correlated strongly with automated scoring of the same task using a standard high frame rate eye tracker camera.While this method is not suitable for eye tracking paradigms requiring the collection and analysis of fine-grained metrics, such as

  19. Active spectral imaging nondestructive evaluation (SINDE) camera

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-15

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

  20. High resolution RGB color line scan camera

    Science.gov (United States)

    Lynch, Theodore E.; Huettig, Fred

    1998-04-01

    A color line scan camera family which is available with either 6000, 8000 or 10000 pixels/color channel, utilizes off-the-shelf lenses, interfaces with currently available frame grabbers, includes on-board pixel by pixel offset correction, and is configurable and controllable via RS232 serial port for computer controlled or stand alone operation is described in this paper. This line scan camera is based on an available 8000 element monochrome line scan camera designed by AOA for OEM use. The new color version includes improvements such as better packaging and additional user features which make the camera easier to use. The heart of the camera is a tri-linear CCD sensor with on-chip color balancing for maximum accuracy and pinned photodiodes for low lag response. Each color channel is digitized to 12 bits and all three channels are multiplexed together so that the resulting camera output video is either a 12 or 8 bit data stream at a rate of up to 24Megpixels/sec. Conversion from 12 to 8 bit, or user-defined gamma, is accomplished by on board user-defined video look up tables. The camera has two user-selectable operating modes; lows speed, high sensitivity mode or high speed, reduced sensitivity mode. The intended uses of the camera include industrial inspection, digital archiving, document scanning, and graphic arts applications.

  1. An Open Standard for Camera Trap Data

    Directory of Open Access Journals (Sweden)

    Tavis Forrester

    2016-12-01

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

  2. Single chip camera active pixel sensor

    Science.gov (United States)

    Shaw, Timothy (Inventor); Pain, Bedabrata (Inventor); Olson, Brita (Inventor); Nixon, Robert H. (Inventor); Fossum, Eric R. (Inventor); Panicacci, Roger A. (Inventor); Mansoorian, Barmak (Inventor)

    2003-01-01

    A totally digital single chip camera includes communications to operate most of its structure in serial communication mode. The digital single chip camera include a D/A converter for converting an input digital word into an analog reference signal. The chip includes all of the necessary circuitry for operating the chip using a single pin.

  3. Securing Embedded Smart Cameras with Trusted Computing

    Directory of Open Access Journals (Sweden)

    Winkler Thomas

    2011-01-01

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

  4. Centering mount for a gamma camera

    International Nuclear Information System (INIS)

    Mirkhodzhaev, A.Kh.; Kuznetsov, N.K.; Ostryj, Yu.E.

    1988-01-01

    A device for centering a γ-camera detector in case of radionuclide diagnosis is described. It permits the use of available medical coaches instead of a table with a transparent top. The device can be used for centering a detector (when it is fixed at the low end of a γ-camera) on a required area of the patient's body

  5. Digital airborne camera introduction and technology

    CERN Document Server

    Sandau, Rainer

    2014-01-01

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

  6. Adapting virtual camera behaviour through player modelling

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    Research in virtual camera control has focused primarily on finding methods to allow designers to place cameras effectively and efficiently in dynamic and unpredictable environments, and to generate complex and dynamic plans for cinematography in virtual environments. In this article, we propose...

  7. Driving with head-slaved camera system

    NARCIS (Netherlands)

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

    2001-01-01

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

  8. Rosetta Star Tracker and Navigation Camera

    DEFF Research Database (Denmark)

    Thuesen, Gøsta

    1998-01-01

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

  9. Method: a single nucleotide polymorphism genotyping method for Wheat streak mosaic virus

    Science.gov (United States)

    2012-01-01

    Background The September 11, 2001 attacks on the World Trade Center and the Pentagon increased the concern about the potential for terrorist attacks on many vulnerable sectors of the US, including agriculture. The concentrated nature of crops, easily obtainable biological agents, and highly detrimental impacts make agroterrorism a potential threat. Although procedures for an effective criminal investigation and attribution following such an attack are available, important enhancements are still needed, one of which is the capability for fine discrimination among pathogen strains. The purpose of this study was to develop a molecular typing assay for use in a forensic investigation, using Wheat streak mosaic virus (WSMV) as a model plant virus. Method This genotyping technique utilizes single base primer extension to generate a genetic fingerprint. Fifteen single nucleotide polymorphisms (SNPs) within the coat protein and helper component-protease genes were selected as the genetic markers for this assay. Assay optimization and sensitivity testing was conducted using synthetic targets. WSMV strains and field isolates were collected from regions around the world and used to evaluate the assay for discrimination. The assay specificity was tested against a panel of near-neighbors consisting of genetic and environmental near-neighbors. Result Each WSMV strain or field isolate tested produced a unique SNP fingerprint, with the exception of three isolates collected within the same geographic location that produced indistinguishable fingerprints. The results were consistent among replicates, demonstrating the reproducibility of the assay. No SNP fingerprints were generated from organisms included in the near-neighbor panel, suggesting the assay is specific for WSMV. Using synthetic targets, a complete profile could be generated from as low as 7.15 fmoles of cDNA. Conclusion The molecular typing method presented is one tool that could be incorporated into the forensic

  10. Method: a single nucleotide polymorphism genotyping method for Wheat streak mosaic virus.

    Science.gov (United States)

    Rogers, Stephanie M; Payton, Mark; Allen, Robert W; Melcher, Ulrich; Carver, Jesse; Fletcher, Jacqueline

    2012-05-17

    The September 11, 2001 attacks on the World Trade Center and the Pentagon increased the concern about the potential for terrorist attacks on many vulnerable sectors of the US, including agriculture. The concentrated nature of crops, easily obtainable biological agents, and highly detrimental impacts make agroterrorism a potential threat. Although procedures for an effective criminal investigation and attribution following such an attack are available, important enhancements are still needed, one of which is the capability for fine discrimination among pathogen strains. The purpose of this study was to develop a molecular typing assay for use in a forensic investigation, using Wheat streak mosaic virus (WSMV) as a model plant virus. This genotyping technique utilizes single base primer extension to generate a genetic fingerprint. Fifteen single nucleotide polymorphisms (SNPs) within the coat protein and helper component-protease genes were selected as the genetic markers for this assay. Assay optimization and sensitivity testing was conducted using synthetic targets. WSMV strains and field isolates were collected from regions around the world and used to evaluate the assay for discrimination. The assay specificity was tested against a panel of near-neighbors consisting of genetic and environmental near-neighbors. Each WSMV strain or field isolate tested produced a unique SNP fingerprint, with the exception of three isolates collected within the same geographic location that produced indistinguishable fingerprints. The results were consistent among replicates, demonstrating the reproducibility of the assay. No SNP fingerprints were generated from organisms included in the near-neighbor panel, suggesting the assay is specific for WSMV. Using synthetic targets, a complete profile could be generated from as low as 7.15 fmoles of cDNA. The molecular typing method presented is one tool that could be incorporated into the forensic science tool box after a thorough

  11. Wavefront analysis for plenoptic camera imaging

    International Nuclear Information System (INIS)

    Luan Yin-Sen; Xu Bing; Yang Ping; Tang Guo-Mao

    2017-01-01

    The plenoptic camera is a single lens stereo camera which can retrieve the direction of light rays while detecting their intensity distribution. In this paper, to reveal more truths of plenoptic camera imaging, we present the wavefront analysis for the plenoptic camera imaging from the angle of physical optics but not from the ray tracing model of geometric optics. Specifically, the wavefront imaging model of a plenoptic camera is analyzed and simulated by scalar diffraction theory and the depth estimation is redescribed based on physical optics. We simulate a set of raw plenoptic images of an object scene, thereby validating the analysis and derivations and the difference between the imaging analysis methods based on geometric optics and physical optics are also shown in simulations. (paper)

  12. Modelling Virtual Camera Behaviour Through Player Gaze

    DEFF Research Database (Denmark)

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

    2012-01-01

    industry and game AI research focus on the devel- opment of increasingly sophisticated systems to automate the control of the virtual camera integrating artificial intel- ligence algorithms within physical simulations. However, in both industry and academia little research has been carried out......In a three-dimensional virtual environment, aspects such as narrative and interaction largely depend on the placement and animation of the virtual camera. Therefore, virtual camera control plays a critical role in player experience and, thereby, in the overall quality of a computer game. Both game...... on the relationship between virtual camera, game-play and player behaviour. We run a game user experiment to shed some light on this relationship and identify relevant dif- ferences between camera behaviours through different game sessions, playing behaviours and player gaze patterns. Re- sults show that users can...

  13. Stereo Cameras for Clouds (STEREOCAM) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-10-31

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

  14. Gamma camera performance: technical assessment protocol

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  15. Rapid objective measurement of gamma camera resolution using statistical moments.

    Science.gov (United States)

    Hander, T A; Lancaster, J L; Kopp, D T; Lasher, J C; Blumhardt, R; Fox, P T

    1997-02-01

    An easy and rapid method for the measurement of the intrinsic spatial resolution of a gamma camera was developed. The measurement is based on the first and second statistical moments of regions of interest (ROIs) applied to bar phantom images. This leads to an estimate of the modulation transfer function (MTF) and the full-width-at-half-maximum (FWHM) of a line spread function (LSF). Bar phantom images were acquired using four large field-of-view (LFOV) gamma cameras (Scintronix, Picker, Searle, Siemens). The following factors important for routine measurements of gamma camera resolution with this method were tested: ROI placement and shape, phantom orientation, spatial sampling, and procedural consistency. A 0.2% coefficient of variation (CV) between repeat measurements of MTF was observed for a circular ROI. The CVs of less than 2% were observed for measured MTF values for bar orientations ranging from -10 degrees to +10 degrees with respect to the x and y axes of the camera acquisition matrix. A 256 x 256 matrix (1.6 mm pixel spacing) was judged sufficient for routine measurements, giving an estimate of the FWHM to within 0.1 mm of manufacturer-specified values (3% difference). Under simulated clinical conditions, the variation in measurements attributable to procedural effects yielded a CV of less than 2% in newer generation cameras. The moments method for determining MTF correlated well with a peak-valley method, with an average difference of 0.03 across the range of spatial frequencies tested (0.11-0.17 line pairs/mm, corresponding to 4.5-3.0 mm bars). When compared with the NEMA method for measuring intrinsic spatial resolution, the moments method was found to be within 4% of the expected FWHM.

  16. Radioactive sampler observation device

    International Nuclear Information System (INIS)

    Tanaka, Norihiko; Saito, Norihisa.

    1996-01-01

    When an object of observation is a fuel rod and if a specimen in a fuel pool is small, it takes much labor for the observation and micro-observation images at a high ratio can not be displayed. A pipe for containing an observing camera in a water-sealed state, a jack capable of adjusting the focus of the observation camera by remote control and a horizontal bed capable of controlling the position of the observation camera for observing the specimen are disposed on a rail formed on lead block shielding walls. The magnification ratio for the observation can be increased by exchanging a die for securing the specimen and a lens, and a transparent acrylic resin plate, or a transparent lead-incorporated glass plate is joined to the bottom of the pipe. Since the sampled specimen can be observed as it is irrespective of the shape or the size of the specimen to be observed, danger of radiation exposure caused such as upon cutting, transportation or fabrication of the radioactive specimen can be reduced. Further, observation underwater can be conducted by the water sealing treatment of the pipe for the observing camera. (N.H.)

  17. Development of high-speed video cameras

    Science.gov (United States)

    Etoh, Takeharu G.; Takehara, Kohsei; Okinaka, Tomoo; Takano, Yasuhide; Ruckelshausen, Arno; Poggemann, Dirk

    2001-04-01

    Presented in this paper is an outline of the R and D activities on high-speed video cameras, which have been done in Kinki University since more than ten years ago, and are currently proceeded as an international cooperative project with University of Applied Sciences Osnabruck and other organizations. Extensive marketing researches have been done, (1) on user's requirements on high-speed multi-framing and video cameras by questionnaires and hearings, and (2) on current availability of the cameras of this sort by search of journals and websites. Both of them support necessity of development of a high-speed video camera of more than 1 million fps. A video camera of 4,500 fps with parallel readout was developed in 1991. A video camera with triple sensors was developed in 1996. The sensor is the same one as developed for the previous camera. The frame rate is 50 million fps for triple-framing and 4,500 fps for triple-light-wave framing, including color image capturing. Idea on a video camera of 1 million fps with an ISIS, In-situ Storage Image Sensor, was proposed in 1993 at first, and has been continuously improved. A test sensor was developed in early 2000, and successfully captured images at 62,500 fps. Currently, design of a prototype ISIS is going on, and, hopefully, will be fabricated in near future. Epoch-making cameras in history of development of high-speed video cameras by other persons are also briefly reviewed.

  18. Payload topography camera of Chang'e-3

    International Nuclear Information System (INIS)

    Yu, Guo-Bin; Liu, En-Hai; Zhao, Ru-Jin; Zhong, Jie; Zhou, Xiang-Dong; Zhou, Wu-Lin; Wang, Jin; Chen, Yuan-Pei; Hao, Yong-Jie

    2015-01-01

    Chang'e-3 was China's first soft-landing lunar probe that achieved a successful roving exploration on the Moon. A topography camera functioning as the lander's “eye” was one of the main scientific payloads installed on the lander. It was composed of a camera probe, an electronic component that performed image compression, and a cable assembly. Its exploration mission was to obtain optical images of the lunar topography in the landing zone for investigation and research. It also observed rover movement on the lunar surface and finished taking pictures of the lander and rover. After starting up successfully, the topography camera obtained static images and video of rover movement from different directions, 360° panoramic pictures of the lunar surface around the lander from multiple angles, and numerous pictures of the Earth. All images of the rover, lunar surface, and the Earth were clear, and those of the Chinese national flag were recorded in true color. This paper describes the exploration mission, system design, working principle, quality assessment of image compression, and color correction of the topography camera. Finally, test results from the lunar surface are provided to serve as a reference for scientific data processing and application. (paper)

  19. Hardware Middleware for Person Tracking on Embedded Distributed Smart Cameras

    Directory of Open Access Journals (Sweden)

    Ali Akbar Zarezadeh

    2012-01-01

    Full Text Available Tracking individuals is a prominent application in such domains like surveillance or smart environments. This paper provides a development of a multiple camera setup with jointed view that observes moving persons in a site. It focuses on a geometry-based approach to establish correspondence among different views. The expensive computational parts of the tracker are hardware accelerated via a novel system-on-chip (SoC design. In conjunction with this vision application, a hardware object request broker (ORB middleware is presented as the underlying communication system. The hardware ORB provides a hardware/software architecture to achieve real-time intercommunication among multiple smart cameras. Via a probing mechanism, a performance analysis is performed to measure network latencies, that is, time traversing the TCP/IP stack, in both software and hardware ORB approaches on the same smart camera platform. The empirical results show that using the proposed hardware ORB as client and server in separate smart camera nodes will considerably reduce the network latency up to 100 times compared to the software ORB.

  20. Towards Adaptive Virtual Camera Control In Computer Games

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2011-01-01

    Automatic camera control aims to define a framework to control virtual camera movements in dynamic and unpredictable virtual environments while ensuring a set of desired visual properties. We inves- tigate the relationship between camera placement and playing behaviour in games and build a user...... model of the camera behaviour that can be used to control camera movements based on player preferences. For this purpose, we collect eye gaze, camera and game-play data from subjects playing a 3D platform game, we cluster gaze and camera information to identify camera behaviour profiles and we employ...... camera control in games is discussed....

  1. Reducing the Variance of Intrinsic Camera Calibration Results in the ROS Camera_Calibration Package

    Science.gov (United States)

    Chiou, Geoffrey Nelson

    The intrinsic calibration of a camera is the process in which the internal optical and geometric characteristics of the camera are determined. If accurate intrinsic parameters of a camera are known, the ray in 3D space that every point in the image lies on can be determined. Pairing with another camera allows for the position of the points in the image to be calculated by intersection of the rays. Accurate intrinsics also allow for the position and orientation of a camera relative to some world coordinate system to be calculated. These two reasons for having accurate intrinsic calibration for a camera are especially important in the field of industrial robotics where 3D cameras are frequently mounted on the ends of manipulators. In the ROS (Robot Operating System) ecosystem, the camera_calibration package is the default standard for intrinsic camera calibration. Several researchers from the Industrial Robotics & Automation division at Southwest Research Institute have noted that this package results in large variances in the intrinsic parameters of the camera when calibrating across multiple attempts. There are also open issues on this matter in their public repository that have not been addressed by the developers. In this thesis, we confirm that the camera_calibration package does indeed return different results across multiple attempts, test out several possible hypothesizes as to why, identify the reason, and provide simple solution to fix the cause of the issue.

  2. Automatic fog detection for public safety by using camera images

    Science.gov (United States)

    Pagani, Giuliano Andrea; Roth, Martin; Wauben, Wiel

    2017-04-01

    Fog and reduced visibility have considerable impact on the performance of road, maritime, and aeronautical transportation networks. The impact ranges from minor delays to more serious congestions or unavailability of the infrastructure and can even lead to damage or loss of lives. Visibility is traditionally measured manually by meteorological observers using landmarks at known distances in the vicinity of the observation site. Nowadays, distributed cameras facilitate inspection of more locations from one remote monitoring center. The main idea is, however, still deriving the visibility or presence of fog by an operator judging the scenery and the presence of landmarks. Visibility sensors are also used, but they are rather costly and require regular maintenance. Moreover, observers, and in particular sensors, give only visibility information that is representative for a limited area. Hence the current density of visibility observations is insufficient to give detailed information on the presence of fog. Cameras are more and more deployed for surveillance and security reasons in cities and for monitoring traffic along main transportation ways. In addition to this primary use of cameras, we consider cameras as potential sensors to automatically identify low visibility conditions. The approach that we follow is to use machine learning techniques to determine the presence of fog and/or to make an estimation of the visibility. For that purpose a set of features are extracted from the camera images such as the number of edges, brightness, transmission of the image dark channel, fractal dimension. In addition to these image features, we also consider meteorological variables such as wind speed, temperature, relative humidity, and dew point as additional features to feed the machine learning model. The results obtained with a training and evaluation set consisting of 10-minute sampled images for two KNMI locations over a period of 1.5 years by using decision trees methods

  3. ERK inhibition promotes neuroectodermal precursor commitment by blocking self-renewal and primitive streak formation of the epiblast.

    Science.gov (United States)

    Yu, Yang; Wang, Xiaoxiao; Zhang, Xiaoxin; Zhai, Yanhua; Lu, Xukun; Ma, Haixia; Zhu, Kai; Zhao, Tongbiao; Jiao, Jianwei; Zhao, Zhen-Ao; Li, Lei

    2018-01-05

    Pluripotent stem cells hold great promise for regenerative medicine. However, before clinical application, reproducible protocols for pluripotent stem cell differentiation should be established. Extracellular signal-regulated protein kinase (ERK) signaling plays a central role for the self-renewal of epiblast stem cells (EpiSCs), but its role for subsequent germ layer differentiation is still ambiguous. We proposed that ERK could modulate differentiation of the epiblast. PD0325901 was used to inhibit ERK activation during the differentiation of embryonic stem cells and EpiSCs. Immunofluorescence, western blot analysis, real-time PCR and flow cytometry were used to detect germ layer markers and pathway activation. We demonstrate that the ERK phosphorylation level is lower in neuroectoderm of mouse E7.5 embryos than that in the primitive streak. ERK inhibition results in neural lineage commitment of epiblast. Mechanistically, PD0325901 abrogates the expression of primitive streak markers by β-catenin retention in the cytoplasm, and inhibits the expression of OCT4 and NANOG during EpiSC differentiation. Thus, EpiSCs differentiate into neuroectodermal lineage efficiently under PD0325901 treatment. These results suggest that neuroectoderm differentiation does not require extrinsic signals, supporting the default differentiation of neural lineage. We report that a single ERK inhibitor, PD0325901, can specify epiblasts and EpiSCs into neural-like cells, providing an efficient strategy for neural differentiation.

  4. Effectiveness of several dosage formula of oil and nano emulsion of citronella against vascular streak dieback (VSD) disease on cocoa

    Science.gov (United States)

    Noveriza, R.; Trisno, J.; Rahma, H.; Yuliani, S.; Reflin; Martinius

    2018-02-01

    The disease of Vascular streak dieback (VSD) is a deadly disease of cocoa plants, because it attacks the vascular tissue of cocoa at growing point of the plant. In West Sumatra the disease was first reported in 2015 with an incidence of disease range 58.82% - 100% and an intensity of disease range 24.29% - 44.7%. The purpose of this study was to examine the effectiveness of dosage application of oil formula and nano emulsion of citronella formula against Vascular streak dieback (VSD) disease on cocoa plants in West Sumatra (in Padang Pariaman District and Limapuluh Kota District). The results showed that the percentage of VSD disease attacks in both testing sites was 100%. The oil and nano emulsion of citronella formulas can reduce the intensity of VSD disease on cocoa plants in West Sumatra, particularly in Padang Pariaman District and Limapuluh Kota District. The reduction of VSD intensity in Padang Pariaman district ranged from 8.32 to 21.13%; while in Limapuluh Kota district ranged from 4.33 to 11.80%. The nano emulsion of citronella formulation is effective to suppress the intensity of VSD disease on cocoa plants at doses 0.1% (≥ 30% of effectiveness level).

  5. Adaptation Computing Parameters of Pan-Tilt-Zoom Cameras for Traffic Monitoring

    Directory of Open Access Journals (Sweden)

    Ya Lin WU

    2014-01-01

    Full Text Available The Closed- CIRCUIT television (CCTV cameras have been widely used in recent years for traffic monitoring and surveillance applications. We can use CCTV cameras to extract automatically real-time traffic parameters according to the image processing and tracking technologies. Especially, the pan-tilt-zoom (PTZ cameras can provide flexible view selection as well as a wider observation range, and this makes the traffic parameters can be accurately calculated. Therefore, that the parameters of PTZ cameras are calibrated plays an important role in vision-based traffic applications. However, in the specific traffic environment, which is that the license plate number of the illegal parking is located, the parameters of PTZ cameras have to be updated according to the position and distance of illegal parking. In proposed traffic monitoring systems, we use the ordinary webcam and PTZ camera. We get vanishing-point of traffic lane lines in the pixel-based coordinate system by fixed webcam. The parameters of PTZ camera can be initialized by distance of the traffic monitoring and specific objectives and vanishing-point. And then we can use the coordinate position of the illegally parked car to update the parameters of PTZ camera and then get the real word coordinate position of the illegally parked car and use it to compute the distance. The result shows the error of the tested distance and real distance is only 0.2064 meter.

  6. Automatic camera tracking for remote manipulators

    International Nuclear Information System (INIS)

    Stoughton, R.S.; Martin, H.L.; Bentz, R.R.

    1984-04-01

    The problem of automatic camera tracking of mobile objects is addressed with specific reference to remote manipulators and using either fixed or mobile cameras. The technique uses a kinematic approach employing 4 x 4 coordinate transformation matrices to solve for the needed camera PAN and TILT angles. No vision feedback systems are used, as the required input data are obtained entirely from position sensors from the manipulator and the camera-positioning system. All hardware requirements are generally satisfied by currently available remote manipulator systems with a supervisory computer. The system discussed here implements linear plus on/off (bang-bang) closed-loop control with a +-2 0 deadband. The deadband area is desirable to avoid operator seasickness caused by continuous camera movement. Programming considerations for camera control, including operator interface options, are discussed. The example problem presented is based on an actual implementation using a PDP 11/34 computer, a TeleOperator Systems SM-229 manipulator, and an Oak Ridge National Laboratory (ORNL) camera-positioning system. 3 references, 6 figures, 2 tables

  7. Automatic camera tracking for remote manipulators

    International Nuclear Information System (INIS)

    Stoughton, R.S.; Martin, H.L.; Bentz, R.R.

    1984-07-01

    The problem of automatic camera tracking of mobile objects is addressed with specific reference to remote manipulators and using either fixed or mobile cameras. The technique uses a kinematic approach employing 4 x 4 coordinate transformation matrices to solve for the needed camera PAN and TILT angles. No vision feedback systems are used, as the required input data are obtained entirely from position sensors from the manipulator and the camera-positioning system. All hardware requirements are generally satisfied by currently available remote manipulator systems with a supervisory computer. The system discussed here implements linear plus on/off (bang-bang) closed-loop control with a +-2-deg deadband. The deadband area is desirable to avoid operator seasickness caused by continuous camera movement. Programming considerations for camera control, including operator interface options, are discussed. The example problem presented is based on an actual implementation using a PDP 11/34 computer, a TeleOperator Systems SM-229 manipulator, and an Oak Ridge National Laboratory (ORNL) camera-positioning system. 3 references, 6 figures, 2 tables

  8. New camera systems for fuel services

    International Nuclear Information System (INIS)

    Hummel, W.; Beck, H.J.

    2010-01-01

    AREVA NP Fuel Services have many years of experience in visual examination and measurements on fuel assemblies and associated core components by using state of the art cameras and measuring technologies. The used techniques allow the surface and dimensional characterization of materials and shapes by visual examination. New enhanced and sophisticated technologies for fuel services f. e. are two shielded color camera systems for use under water and close inspection of a fuel assembly. Nowadays the market requirements for detecting and characterization of small defects (lower than the 10th of one mm) or cracks and analyzing surface appearances on an irradiated fuel rod cladding or fuel assembly structure parts have increased. Therefore it is common practice to use movie cameras with higher resolution. The radiation resistance of high resolution CCD cameras is in general very low and it is not possible to use them unshielded close to a fuel assembly. By extending the camera with a mirror system and shielding around the sensitive parts, the movie camera can be utilized for fuel assembly inspection. AREVA NP Fuel Services is now equipped with such kind of movie cameras. (orig.)

  9. First results from the TOPSAT camera

    Science.gov (United States)

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

    2017-11-01

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

  10. Fuzzy logic control for camera tracking system

    Science.gov (United States)

    Lea, Robert N.; Fritz, R. H.; Giarratano, J.; Jani, Yashvant

    1992-01-01

    A concept utilizing fuzzy theory has been developed for a camera tracking system to provide support for proximity operations and traffic management around the Space Station Freedom. Fuzzy sets and fuzzy logic based reasoning are used in a control system which utilizes images from a camera and generates required pan and tilt commands to track and maintain a moving target in the camera's field of view. This control system can be implemented on a fuzzy chip to provide an intelligent sensor for autonomous operations. Capabilities of the control system can be expanded to include approach, handover to other sensors, caution and warning messages.

  11. A Benchmark for Virtual Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    Automatically animating and placing the virtual camera in a dynamic environment is a challenging task. The camera is expected to maximise and maintain a set of properties — i.e. visual composition — while smoothly moving through the environment and avoiding obstacles. A large number of different....... For this reason, in this paper, we propose a benchmark for the problem of virtual camera control and we analyse a number of different problems in different virtual environments. Each of these scenarios is described through a set of complexity measures and, as a result of this analysis, a subset of scenarios...

  12. Scintillation camera with second order resolution

    International Nuclear Information System (INIS)

    Muehllehner, G.

    1976-01-01

    A scintillation camera for use in radioisotope imaging to determine the concentration of radionuclides in a two-dimensional area is described in which means is provided for second order positional resolution. The phototubes, which normally provide only a single order of resolution, are modified to provide second order positional resolution of radiation within an object positioned for viewing by the scintillation camera. The phototubes are modified in that multiple anodes are provided to receive signals from the photocathode in a manner such that each anode is particularly responsive to photoemissions from a limited portion of the photocathode. Resolution of radioactive events appearing as an output of this scintillation camera is thereby improved

  13. Structure-From for Calibration of a Vehicle Camera System with Non-Overlapping Fields-Of in AN Urban Environment

    Science.gov (United States)

    Hanel, A.; Stilla, U.

    2017-05-01

    Vehicle environment cameras observing traffic participants in the area around a car and interior cameras observing the car driver are important data sources for driver intention recognition algorithms. To combine information from both camera groups, a camera system calibration can be performed. Typically, there is no overlapping field-of-view between environment and interior cameras. Often no marked reference points are available in environments, which are a large enough to cover a car for the system calibration. In this contribution, a calibration method for a vehicle camera system with non-overlapping camera groups in an urban environment is described. A-priori images of an urban calibration environment taken with an external camera are processed with the structure-frommotion method to obtain an environment point cloud. Images of the vehicle interior, taken also with an external camera, are processed to obtain an interior point cloud. Both point clouds are tied to each other with images of both image sets showing the same real-world objects. The point clouds are transformed into a self-defined vehicle coordinate system describing the vehicle movement. On demand, videos can be recorded with the vehicle cameras in a calibration drive. Poses of vehicle environment cameras and interior cameras are estimated separately using ground control points from the respective point cloud. All poses of a vehicle camera estimated for different video frames are optimized in a bundle adjustment. In an experiment, a point cloud is created from images of an underground car park, as well as a point cloud of the interior of a Volkswagen test car is created. Videos of two environment and one interior cameras are recorded. Results show, that the vehicle camera poses are estimated successfully especially when the car is not moving. Position standard deviations in the centimeter range can be achieved for all vehicle cameras. Relative distances between the vehicle cameras deviate between

  14. Advantages of computer cameras over video cameras/frame grabbers for high-speed vision applications

    Science.gov (United States)

    Olson, Gaylord G.; Walker, Jo N.

    1997-09-01

    Cameras designed to work specifically with computers can have certain advantages in comparison to the use of cameras loosely defined as 'video' cameras. In recent years the camera type distinctions have become somewhat blurred, with a great presence of 'digital cameras' aimed more at the home markets. This latter category is not considered here. The term 'computer camera' herein is intended to mean one which has low level computer (and software) control of the CCD clocking. These can often be used to satisfy some of the more demanding machine vision tasks, and in some cases with a higher rate of measurements than video cameras. Several of these specific applications are described here, including some which use recently designed CCDs which offer good combinations of parameters such as noise, speed, and resolution. Among the considerations for the choice of camera type in any given application would be such effects as 'pixel jitter,' and 'anti-aliasing.' Some of these effects may only be relevant if there is a mismatch between the number of pixels per line in the camera CCD and the number of analog to digital (A/D) sampling points along a video scan line. For the computer camera case these numbers are guaranteed to match, which alleviates some measurement inaccuracies and leads to higher effective resolution.

  15. Lunar Reconnaissance Orbiter Camera (LROC) instrument overview

    Science.gov (United States)

    Robinson, M.S.; Brylow, S.M.; Tschimmel, M.; Humm, D.; Lawrence, S.J.; Thomas, P.C.; Denevi, B.W.; Bowman-Cisneros, E.; Zerr, J.; Ravine, M.A.; Caplinger, M.A.; Ghaemi, F.T.; Schaffner, J.A.; Malin, M.C.; Mahanti, P.; Bartels, A.; Anderson, J.; Tran, T.N.; Eliason, E.M.; McEwen, A.S.; Turtle, E.; Jolliff, B.L.; Hiesinger, H.

    2010-01-01

    The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) and Narrow Angle Cameras (NACs) are on the NASA Lunar Reconnaissance Orbiter (LRO). The WAC is a 7-color push-frame camera (100 and 400 m/pixel visible and UV, respectively), while the two NACs are monochrome narrow-angle linescan imagers (0.5 m/pixel). The primary mission of LRO is to obtain measurements of the Moon that will enable future lunar human exploration. The overarching goals of the LROC investigation include landing site identification and certification, mapping of permanently polar shadowed and sunlit regions, meter-scale mapping of polar regions, global multispectral imaging, a global morphology base map, characterization of regolith properties, and determination of current impact hazards.

  16. Gamma camera performance: technical assessment protocol

    International Nuclear Information System (INIS)

    Bolster, A.A.; Waddington, W.A.

    1996-01-01

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

  17. Camera Based Navigation System with Augmented Reality

    Directory of Open Access Journals (Sweden)

    M. Marcu

    2012-06-01

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

  18. CALIBRATION PROCEDURES ON OBLIQUE CAMERA SETUPS

    Directory of Open Access Journals (Sweden)

    G. Kemper

    2016-06-01

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

  19. Portable mini gamma camera for medical applications

    CERN Document Server

    Porras, E; Benlloch, J M; El-Djalil-Kadi-Hanifi, M; López, S; Pavon, N; Ruiz, J A; Sánchez, F; Sebastiá, A

    2002-01-01

    A small, portable and low-cost gamma camera for medical applications has been developed and clinically tested. This camera, based on a scintillator crystal and a Position Sensitive Photo-Multiplier Tube, has a useful field of view of 4.6 cm diameter and provides 2.2 mm of intrinsic spatial resolution. Its mobility and light weight allow to reach the patient from any desired direction. This camera images small organs with high efficiency and so addresses the demand for devices of specific clinical applications. In this paper, we present the camera and briefly describe the procedures that have led us to choose its configuration and the image reconstruction method. The clinical tests and diagnostic capability are also presented and discussed.

  20. An imaging system for a gamma camera

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.

    1980-01-01

    A detailed description is given of a novel gamma camera which is designed to produce superior images than conventional cameras used in nuclear medicine. The detector consists of a solid state detector (e.g. germanium) which is formed to have a plurality of discrete components to enable 2-dimensional position identification. Details of the electronic processing circuits are given and the problems and limitations introduced by noise are discussed in full. (U.K.)