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Sample records for kilohertz frame rate

  1. Dynamic phase-sensitive optical coherence elastography at a true kilohertz frame-rate

    NASA Astrophysics Data System (ADS)

    Singh, Manmohan; Wu, Chen; Liu, Chih-Hao; Li, Jiasong; Schill, Alexander; Nair, Achuth; Larin, Kirill V.

    2016-03-01

    Dynamic optical coherence elastography (OCE) techniques have rapidly emerged as a noninvasive way to characterize the biomechanical properties of tissue. However, clinical applications of the majority of these techniques have been unfeasible due to the extended acquisition time because of multiple temporal OCT acquisitions (M-B mode). Moreover, multiple excitations, large datasets, and prolonged laser exposure prohibit their translation to the clinic, where patient discomfort and safety are critical criteria. Here, we demonstrate the feasibility of noncontact true kilohertz frame-rate dynamic optical coherence elastography by directly imaging a focused air-pulse induced elastic wave with a home-built phase-sensitive OCE system. The OCE system was based on a 4X buffered Fourier Domain Mode Locked swept source laser with an A-scan rate of ~1.5 MHz, and imaged the elastic wave propagation at a frame rate of ~7.3 kHz. Because the elastic wave directly imaged, only a single excitation was utilized for one line scan measurement. Rather than acquiring multiple temporal scans at successive spatial locations as with previous techniques, here, successive B-scans were acquired over the measurement region (B-M mode). Preliminary measurements were taken on tissue-mimicking agar phantoms of various concentrations, and the results showed good agreement with uniaxial mechanical compression testing. Then, the elasticity of an in situ porcine cornea in the whole eye-globe configuration at various intraocular pressures was measured. The results showed that this technique can acquire a depth-resolved elastogram in milliseconds. Furthermore, the ultra-fast acquisition ensured that the laser safety exposure limit for the cornea was not exceeded.

  2. Multiterawatt femtosecond laser system with kilohertz pulse repetition rate

    SciTech Connect

    Petrov, V V; Pestryakov, E V; Laptev, A V; Petrov, V A; Kuptsov, G V; Trunov, V I; Frolov, S A

    2014-05-30

    The basic principles, layout and components are presented for a multiterawatt femtosecond laser system with a kilohertz pulse repetition rate f, based on their parametric amplification and laser amplification of picosecond radiation that pumps the stages of the parametric amplifier. The results of calculations for a step-by-step increase in the output power from the LBO crystal parametric amplifier channel up to the multiterawatt level are presented. By using the developed components in the pump channel of the laser system, the parameters of the regenerative amplifier with the output energy ∼1 mJ at the wavelength 1030 nm and with f = 1 kHz are experimentally studied. The optical scheme of the diode-pumped multipass cryogenic Yb:Y{sub 2}O{sub 3} laser ceramic amplifier is developed and its characteristics are determined that provide the output energy within the range 0.25 – 0.35 J. (lasers)

  3. Multiterawatt femtosecond laser system with kilohertz pulse repetition rate

    NASA Astrophysics Data System (ADS)

    Petrov, V. V.; Pestryakov, E. V.; Laptev, A. V.; Petrov, V. A.; Kuptsov, G. V.; Trunov, V. I.; Frolov, S. A.

    2014-05-01

    The basic principles, layout and components are presented for a multiterawatt femtosecond laser system with a kilohertz pulse repetition rate f, based on their parametric amplification and laser amplification of picosecond radiation that pumps the stages of the parametric amplifier. The results of calculations for a step-by-step increase in the output power from the LBO crystal parametric amplifier channel up to the multiterawatt level are presented. By using the developed components in the pump channel of the laser system, the parameters of the regenerative amplifier with the output energy ~1 mJ at the wavelength 1030 nm and with f = 1 kHz are experimentally studied. The optical scheme of the diode-pumped multipass cryogenic Yb:Y2O3 laser ceramic amplifier is developed and its characteristics are determined that provide the output energy within the range 0.25 - 0.35 J.

  4. Frame Rate and Human Vision

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B.

    2012-01-01

    To enhance the quality of the theatre experience, the film industry is interested in achieving higher frame rates for capture and display. In this talk I will describe the basic spatio-temporal sensitivities of human vision, and how they respond to the time sequence of static images that is fundamental to cinematic presentation.

  5. Solid-state YVO4/Nd:YVO4/KTP green laser system for the generation of subnanosecond pulses with adjustable kilohertz repetition rate.

    PubMed

    Zhang, Haijuan; Zhao, Shengzhi; Yang, Kejian; Li, Guiqiu; Li, Dechun; Zhao, Jia; Wang, Yonggang

    2013-09-20

    A solid-state green laser generating subnanosecond pulses with adjustable kilohertz repetition rate is presented. This pulse laser system is composed of a Q-switched and mode-locked YVO(4)/Nd:YVO(4)/KTP laser simultaneously modulated by an electro-optic (EO) modulator and a central semiconductor saturable absorption mirror. Because the repetition rate of the Q-switched envelope in this laser depends on the modulation frequency of the EO modulator, so long as the pulsewidth of the Q-switched envelope is shorter than the cavity roundtrip transmit time, i.e., the time interval of two neighboring mode-locking pulses, only one mode-locking pulse exists underneath a Q-switched envelope, resulting in the generation of subnanosecond pulses with kilohertz repetition rate. The experimental results show that the pulsewidth of subnanosecond pulses decreases with increasing pump power and the shortest pulse generated at 1 kHz was 450 ps with pulse energy as high as 252 μJ, corresponding to a peak power of 560 kW. In addition, this laser was confirmed to have high stability, and the pulse repetition rate could be freely adjusted from 1 to 4 kHz. PMID:24085177

  6. Tracking in high-frame-rate imaging.

    PubMed

    Wu, Shih-Ying; Wang, Shun-Li; Li, Pai-Chi

    2010-01-01

    Speckle tracking has been used for motion estimation in ultrasound imaging. Unlike conventional Doppler techniques, which are angle-dependent, speckle tracking can be utilized to estimate velocity vectors. However, the accuracy of speckle-tracking methods is limited by speckle decorrelation, which is related to the displacement between two consecutive images, and, hence, combining high-frame-rate imaging and speckle tracking could potentially increase the accuracy of motion estimation. However, the lack of transmit focusing may also affect the tracking results and the high computational requirement may be problematic. This study therefore assessed the performance of high-frame-rate speckle tracking and compared it with conventional focusing. The effects of the signal-to-noise ratio (SNR), bulk motion, and velocity gradients were investigated in both experiments and simulations. The results show that high-frame-rate speckle tracking can achieve high accuracy if the SNR is sufficiently high. In addition, its computational complexity is acceptable because smaller search windows can be used due to the displacements between frames generally being smaller during high-frame-rate imaging. Speckle decor-relation resulting from velocity gradients within a sample volume is also not as significant during high-frame-rate imaging. PMID:20690428

  7. On the Disappearance of Kilohertz Quasi-periodic Oscillations at a High Mass Accretion Rate in Low-Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Cui, Wei

    2000-05-01

    For all sources in which the phenomenon of kilohertz quasi-periodic oscillation (kHz QPO) is observed, the QPOs disappear abruptly when the inferred mass accretion rate exceeds a certain threshold. Although the threshold cannot at present be accurately determined (or even quantified) observationally, it is clearly higher for bright Z sources than for faint atoll sources. Here we propose that the observational manifestation of kHz QPOs requires direct interaction between the neutron star magnetosphere and the Keplerian accretion disk and that the cessation of kHz QPOs at a high accretion rate is due to the lack of such an interaction when the Keplerian disk terminates at the last stable orbit and yet the magnetosphere is pushed farther inward. The threshold is therefore dependent on the magnetic field strength-the stronger the magnetic field, the higher the threshold. This is certainly in agreement with the atoll/Z paradigm, but we argue that it is also generally true, even for individual sources within each (atoll or Z) category. For atoll sources, the kHz QPOs also seem to vanish at a low accretion rate. Perhaps the ``disengagement'' between the magnetosphere and the Keplerian disk also takes place under such circumstances because of, for instance, the presence of quasi-spherical advection-dominated accretion flow (ADAF) close to the neutron star. Unfortunately, in this case, the estimation of the accretion rate threshold would require a knowledge of the physical mechanisms that cause the disengagement. If the ADAF is responsible, the threshold is likely dependent on the magnetic field of the neutron star.

  8. High frame-rate digital radiographic videography

    SciTech Connect

    King, N.S.P.; Cverna, F.H.; Albright, K.L.; Jaramillo, S.A.; Yates, G.J.; McDonald, T.E.; Flynn, M.J.; Tashman, S.

    1994-09-01

    High speed x-ray imaging can be an important tool for observing internal processes in a wide range of applications. In this paper we describe preliminary implementation of a system having the eventual goal of observing the internal dynamics of bone and joint reactions during loading. Two Los Alamos National Laboratory (LANL) gated and image intensified camera systems were used to record images from an x-ray image convertor tube to demonstrate the potential of high frame-rate digital radiographic videography in the analysis of bone and joint dynamics of the human body. Preliminary experiments were done at LANL to test the systems. Initial high frame-rate imaging (from 500 to 1000 frames/s) of a swinging pendulum mounted to the face of an X-ray image convertor tube demonstrated high contrast response and baseline sensitivity. The systems were then evaluated at the Motion Analysis Laboratory of Henry Ford Health Systems Bone and Joint Center. Imaging of a 9 inch acrylic disk with embedded lead markers rotating at approximately 1000 RPM, demonstrated the system response to a high velocity/high contrast target. By gating the P-20 phosphor image from the X-ray image convertor with a second image intensifier (II) and using a 100-microsecond wide optical gate through the second II, enough prompt light decay from the x-ray image convertor phosphor had taken place to achieve reduction of most of the motion blurring. Measurement of the marker velocity was made by using video frames acquired at 500 frames/s. The data obtained from both experiments successfully demonstrated the feasibility of the technique. Several key areas for improvement are discussed along with salient test results and experiment details.

  9. High-frame-rate digital radiographic videography

    NASA Astrophysics Data System (ADS)

    King, Nicholas S. P.; Cverna, Frank H.; Albright, Kevin L.; Jaramillo, Steven A.; Yates, George J.; McDonald, Thomas E.; Flynn, Michael J.; Tashman, Scott

    1994-10-01

    High speed x-ray imaging can be an important tool for observing internal processes in a wide range of applications. In this paper we describe preliminary implementation of a system having the eventual goal of observing the internal dynamics of bone and joint reactions during loading. Two Los Alamos National Laboratory (LANL) gated and image intensified camera systems were used to record images from an x-ray image convertor tube to demonstrate the potential of high frame-rate digital radiographic videography in the analysis of bone and joint dynamics of the human body. Preliminary experiments were done at LANL to test the systems. Initial high frame-rate imaging (from 500 to 1000 frames/s) of a swinging pendulum mounted to the face of an X-ray image convertor tube demonstrated high contrast response and baseline sensitivity. The systems were then evaluated at the Motion Analysis Laboratory of Henry Ford Health Systems Bone and Joint Center. Imaging of a 9 inch acrylic disk with embedded lead markers rotating at approximately 1000 RPM, demonstrated the system response to a high velocity/high contrast target. By gating the P-20 phosphor image from the X-ray image convertor with a second image intensifier (II) and using a 100 microsecond wide optical gate through the second II, enough prompt light decay from the x-ray image convertor phosphor had taken place to achieve reduction of most of the motion blurring. Measurement of the marker velocity was made by using video frames acquired at 500 frames/s. The data obtained from both experiments successfully demonstrated the feasibility of the technique. Several key areas for improvement are discussed along with salient test results and experiment details.

  10. High frame rate fluorescence lifetime imaging

    NASA Astrophysics Data System (ADS)

    Agronskaia, A. V.; Tertoolen, L.; Gerritsen, H. C.

    2003-07-01

    A fast time-domain based fluorescence lifetime imaging (FLIM) microscope is presented that can operate at frame rates of hundreds of frames per second. A beam splitter in the detection path of a wide-field fluorescence microscope divides the fluorescence in two parts. One part is optically delayed with respect to the other. Both parts are viewed with a single time-gated intensified CCD camera with a gate width of 5 ns. The fluorescence lifetime image is obtained from the ratio of these two images. The fluorescence lifetime resolution of the FLIM microscope is verified both with dye solutions and fluorescent latex beads. The fluorescence lifetimes obtained from the reference specimens are in good agreement with values obtained from time correlated single photon counting measurements on the same specimens. The acquisition speed of the FLIM system is evaluated with a measurement of the calcium fluxes in neonatal rat myocytes stained with the calcium probe Oregon Green 488-Bapta. Fluorescence lifetime images of the calcium fluxes related to the beating of the myocytes are acquired with frame rates of up to 100 Hz.

  11. Effect of triggered discharge using an excimer laser with high-repetition-rate of the order of kilohertz

    SciTech Connect

    Yamaura, Michiteru; Watanabe, Takashi; Hayashi, Nobuya; Ihara, Satoshi

    2005-03-28

    The triggering ability of the laser-triggered lightning method is improved by using a KrF excimer laser with a high-repetition-rate of the order of kHz order. It is clarified that the effect of a triggered discharge is considerably enhanced when the plasma density is greater than 10{sup 13} cm{sup -3}. Thus far, the laser-triggered lightning method has not been expected to display a triggering ability since one pulse of an excimer laser possesses energy of less than 1 J, and the produced plasma has a low density of 10{sup 12} cm{sup -3}, its plasma density is one order lower than that required for its application in the triggering and guiding of lightning discharge. The enhancement of plasma density achieved by utilizing the accumulation effect of charged particles generated by the high-repetition-rate laser was 10{sup 13} cm{sup -3}. This led to an effective a 50% reduction in the self-breakdown voltage.

  12. High Resolution, High Frame Rate Video Technology

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Papers and working group summaries presented at the High Resolution, High Frame Rate Video (HHV) Workshop are compiled. HHV system is intended for future use on the Space Shuttle and Space Station Freedom. The Workshop was held for the dual purpose of: (1) allowing potential scientific users to assess the utility of the proposed system for monitoring microgravity science experiments; and (2) letting technical experts from industry recommend improvements to the proposed near-term HHV system. The following topics are covered: (1) State of the art in the video system performance; (2) Development plan for the HHV system; (3) Advanced technology for image gathering, coding, and processing; (4) Data compression applied to HHV; (5) Data transmission networks; and (6) Results of the users' requirements survey conducted by NASA.

  13. Using Temporal Fill Factor to Reduce Frame Reconstruction Rates

    NASA Technical Reports Server (NTRS)

    Larimer, James; Balram, Nikhil; Gille, Jennifer; Luszcz, Jeffery

    1997-01-01

    The newer active matrix display technologies such as TFT-LCD, DMD, PDP maintain their pixel values through the entire frame time, presenting a 100% temporal fill factor, in contrast to the duty cycle produced by the phosphor impulse response of the CRT. This sample-and-hold characteristic can be exploited to lower the displayed frame rate without affecting visual quality. The lower frame rate results in significantly lower transmission bandwidth, power, and cost.

  14. Rate control algorithm based on frame complexity estimation for MVC

    NASA Astrophysics Data System (ADS)

    Yan, Tao; An, Ping; Shen, Liquan; Zhang, Zhaoyang

    2010-07-01

    Rate control has not been well studied for multi-view video coding (MVC). In this paper, we propose an efficient rate control algorithm for MVC by improving the quadratic rate-distortion (R-D) model, which reasonably allocate bit-rate among views based on correlation analysis. The proposed algorithm consists of four levels for rate bits control more accurately, of which the frame layer allocates bits according to frame complexity and temporal activity. Extensive experiments show that the proposed algorithm can efficiently implement bit allocation and rate control according to coding parameters.

  15. Microdroplet target synthesis for kilohertz ultrafast lasers

    SciTech Connect

    Chvykov, Pavel; Ongg, Wise; Easter, James; Hou, Bixue; Nees, John; Krushelnick, Karl

    2010-12-01

    We have developed a method for producing spatially stable micron-scale liquid targets of flexible shapes at kilohertz repetition rate for use in air and vacuum, by perturbing 5 and 30 {mu}m diameter streams with femtosecond laser pulses and monitoring the temporal development of the perturbation. Using water, we have produced features such as 2.1 {mu}m diameter droplet and 1.3 {mu}m diameter neck with less than {+-}0.3 {mu}m shot-to-shot variation, with prospects for further reduction in size and variability. The use of such micron-scale targets can be expected to prevent conductive heat dissipation, enhance field strength for ion acceleration and allow spatially-deterministic laser-cluster experiments.

  16. Microdroplet target synthesis for kilohertz ultrafast lasers

    NASA Astrophysics Data System (ADS)

    Chvykov, Pavel; Ongg, Wise; Easter, James; Hou, Bixue; Nees, John; Krushelnick, Karl

    2010-12-01

    We have developed a method for producing spatially stable micron-scale liquid targets of flexible shapes at kilohertz repetition rate for use in air and vacuum, by perturbing 5 and 30 μm diameter streams with femtosecond laser pulses and monitoring the temporal development of the perturbation. Using water, we have produced features such as 2.1 μm diameter droplet and 1.3 μm diameter neck with less than ±0.3 μm shot-to-shot variation, with prospects for further reduction in size and variability. The use of such micron-scale targets can be expected to prevent conductive heat dissipation, enhance field strength for ion acceleration and allow spatially-deterministic laser-cluster experiments.

  17. Reducing video frame rate increases remote optimal focus time

    NASA Technical Reports Server (NTRS)

    Haines, Richard F.

    1993-01-01

    Twelve observers made best optical focus adjustments to a microscope whose high-resolution pattern was video monitored and displayed first on a National Television System Committee (NTSC) analog color monitor and second on a digitally compressed computer monitor screen at frame rates ranging (in six steps) from 1.5 to 30 frames per second (fps). This was done to determine whether reducing the frame rate affects the image focus. Reducing frame rate has been shown to be an effective and acceptable means of reducing transmission bandwidth of dynamic video imagery sent from Space Station Freedom (SSF) to ground scientists. Three responses were recorded per trial: time to complete the focus adjustment, number of changes of focus direction, and subjective rating of final image quality. It was found that: the average time to complete the focus setting increases from 4.5 sec at 30 fps to 7.9 sec at 1.5 fps (statistical probability = 1.2 x 10(exp -7)); there is no significant difference in the number of changes in the direction of focus adjustment across these frame rates; and there is no significant change in subjectively determined final image quality across these frame rates. These data can be used to help pre-plan future remote optical-focus operations on SSF.

  18. High frame rate photoacoustic imaging at 7000 frames per second using clinical ultrasound system

    PubMed Central

    Sivasubramanian, Kathyayini; Pramanik, Manojit

    2016-01-01

    Photoacoustic tomography, a hybrid imaging modality combining optical and ultrasound imaging, is gaining attention in the field of medical imaging. Typically, a Q-switched Nd:YAG laser is used to excite the tissue and generate photoacoustic signals. But, such photoacoustic imaging systems are difficult to translate into clinical applications owing to their high cost, bulky size often requiring an optical table to house such lasers. Moreover, the low pulse repetition rate of few tens of hertz prevents them from being used in high frame rate photoacoustic imaging. In this work, we have demonstrated up to 7000 Hz photoacoustic imaging (B-mode) and measured the flow rate of a fast moving object. We used a ~140 nanosecond pulsed laser diode as an excitation source and a clinical ultrasound imaging system to capture and display the photoacoustic images. The excitation laser is ~803 nm in wavelength with ~1.4 mJ energy per pulse. So far, the reported 2-dimensional photoacoustic B-scan imaging is only a few tens of frames per second using a clinical ultrasound system. Therefore, this is the first report on 2-dimensional photoacoustic B-scan imaging with 7000 frames per second. We have demonstrated phantom imaging to view and measure the flow rate of ink solution inside a tube. This fast photoacoustic imaging can be useful for various clinical applications including cardiac related problems, where the blood flow rate is quite high, or other dynamic studies. PMID:26977342

  19. High frame rate photoacoustic imaging at 7000 frames per second using clinical ultrasound system.

    PubMed

    Sivasubramanian, Kathyayini; Pramanik, Manojit

    2016-02-01

    Photoacoustic tomography, a hybrid imaging modality combining optical and ultrasound imaging, is gaining attention in the field of medical imaging. Typically, a Q-switched Nd:YAG laser is used to excite the tissue and generate photoacoustic signals. But, such photoacoustic imaging systems are difficult to translate into clinical applications owing to their high cost, bulky size often requiring an optical table to house such lasers. Moreover, the low pulse repetition rate of few tens of hertz prevents them from being used in high frame rate photoacoustic imaging. In this work, we have demonstrated up to 7000 Hz photoacoustic imaging (B-mode) and measured the flow rate of a fast moving object. We used a ~140 nanosecond pulsed laser diode as an excitation source and a clinical ultrasound imaging system to capture and display the photoacoustic images. The excitation laser is ~803 nm in wavelength with ~1.4 mJ energy per pulse. So far, the reported 2-dimensional photoacoustic B-scan imaging is only a few tens of frames per second using a clinical ultrasound system. Therefore, this is the first report on 2-dimensional photoacoustic B-scan imaging with 7000 frames per second. We have demonstrated phantom imaging to view and measure the flow rate of ink solution inside a tube. This fast photoacoustic imaging can be useful for various clinical applications including cardiac related problems, where the blood flow rate is quite high, or other dynamic studies. PMID:26977342

  20. Corrected High-Frame Rate Anchored Ultrasound with Software Alignment

    ERIC Educational Resources Information Center

    Miller, Amanda L.; Finch, Kenneth B.

    2011-01-01

    Purpose: To improve lingual ultrasound imaging with the Corrected High Frame Rate Anchored Ultrasound with Software Alignment (CHAUSA; Miller, 2008) method. Method: A production study of the IsiXhosa alveolar click is presented. Articulatory-to-acoustic alignment is demonstrated using a Tri-Modal 3-ms pulse generator. Images from 2 simultaneous…

  1. High frame rate CCD camera with fast optical shutter

    SciTech Connect

    Yates, G.J.; McDonald, T.E. Jr.; Turko, B.T.

    1998-09-01

    A high frame rate CCD camera coupled with a fast optical shutter has been designed for high repetition rate imaging applications. The design uses state-of-the-art microchannel plate image intensifier (MCPII) technology fostered/developed by Los Alamos National Laboratory to support nuclear, military, and medical research requiring high-speed imagery. Key design features include asynchronous resetting of the camera to acquire random transient images, patented real-time analog signal processing with 10-bit digitization at 40--75 MHz pixel rates, synchronized shutter exposures as short as 200pS, sustained continuous readout of 512 x 512 pixels per frame at 1--5Hz rates via parallel multiport (16-port CCD) data transfer. Salient characterization/performance test data for the prototype camera are presented, temporally and spatially resolved images obtained from range-gated LADAR field testing are included, an alternative system configuration using several cameras sequenced to deliver discrete numbers of consecutive frames at effective burst rates up to 5GHz (accomplished by time-phasing of consecutive MCPII shutter gates without overlap) is discussed. Potential applications including dynamic radiography and optical correlation will be presented.

  2. Variable frame rate analysis for automatic speech recognition

    NASA Astrophysics Data System (ADS)

    Tan, Zheng-Hua

    2007-09-01

    In this paper we investigate the use of variable frame rate (VFR) analysis in automatic speech recognition (ASR). First, we review VFR technique and analyze its behavior. It is experimentally shown that VFR improves ASR performance for signals with low signal-to-noise ratios since it generates improved acoustic models and substantially reduces insertion and substitution errors although it may increase deletion errors. It is also underlined that the match between the average frame rate and the number of hidden Markov model states is critical in implementing VFR. Secondly, we analyze an effective VFR method that uses a cumulative, weighted cepstral-distance criterion for frame selection and present a revision for it. Lastly, the revised VFR method is combined with spectral- and cepstral-domain enhancement methods including the minimum statistics noise estimation (MSNE) based spectral subtraction and the cepstral mean subtraction, variance normalization and ARMA filtering (MVA) process. Experiments on the Aurora 2 database justify that VFR is highly complementary to the enhancement methods. Enhancement of speech both facilitates the frame selection in VFR and provides de-noised speech for recognition.

  3. Towards hard X-ray imaging at GHz frame rate

    SciTech Connect

    Wang, Zhehui; Morris, Christopher; Luo, Shengnian; Kwiatkowski, Kris K.; Kapustinsky, Jon S.

    2012-05-02

    Gigahertz (GHz) imaging using hard X-rays ({approx}> 10 keV) can be useful to high-temperature plasma experiments, as well as research using coherent photons from synchrotron radiation and X-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one X-ray photon is detected per pixel, are given. Two possible paths towards X-ray imaging at GHz frame rates using a single camera are (a) Avalanche photodiode arrays of high-Z materials and (b) Microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

  4. Towards hard x-ray imaging at GHz frame rate

    SciTech Connect

    Wang Zhehui; Morris, C. L.; Kapustinsky, J. S.; Kwiatkowski, K.; Luo, S.-N.

    2012-10-15

    Gigahertz (GHz) imaging using hard x-rays ( Greater-Than-Or-Equivalent-To 10 keV) can be useful to high-temperature plasma experiments, as well as research and applications using coherent photons from synchrotron radiation and x-ray free electron lasers. GHz framing rate can be achieved by using multiple cameras through multiplexing. The advantages and trade-offs of single-photon detection mode, when no more than one x-ray photon is detected per pixel, are given. Two possible paths towards x-ray imaging at GHz frame rates using a single camera are: (a) avalanche photodiode arrays of high-Z materials and (b) microchannel plate photomultipliers in conjunction with materials with large indices of refraction.

  5. Driving techniques for high frame rate CCD camera

    NASA Astrophysics Data System (ADS)

    Guo, Weiqiang; Jin, Longxu; Xiong, Jingwu

    2008-03-01

    This paper describes a high-frame rate CCD camera capable of operating at 100 frames/s. This camera utilizes Kodak KAI-0340, an interline transfer CCD with 640(vertical)×480(horizontal) pixels. Two output ports are used to read out CCD data and pixel rates approaching 30 MHz. Because of its reduced effective opacity of vertical charge transfer registers, interline transfer CCD can cause undesired image artifacts, such as random white spots and smear generated in the registers. To increase frame rate, a kind of speed-up structure has been incorporated inside KAI-0340, then it is vulnerable to a vertical stripe effect. The phenomena which mentioned above may severely impair the image quality. To solve these problems, some electronic methods of eliminating these artifacts are adopted. Special clocking mode can dump the unwanted charge quickly, then the fast readout of the images, cleared of smear, follows immediately. Amplifier is used to sense and correct delay mismatch between the dual phase vertical clock pulses, the transition edges become close to coincident, so vertical stripes disappear. Results obtained with the CCD camera are shown.

  6. Cheetah: A high frame rate, high resolution SWIR image camera

    NASA Astrophysics Data System (ADS)

    Neys, Joel; Bentell, Jonas; O'Grady, Matt; Vermeiren, Jan; Colin, Thierry; Hooylaerts, Peter; Grietens, Bob

    2008-10-01

    A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 μm] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.

  7. High frame rate photoacoustic imaging using clinical ultrasound system

    NASA Astrophysics Data System (ADS)

    Sivasubramanian, Kathyayini; Pramanik, Manojit

    2016-03-01

    Photoacoustic tomography (PAT) is a potential hybrid imaging modality which is gaining attention in the field of medical imaging. Typically a Q-switched Nd:YAG laser is used to excite the tissue and generate photoacoustic signals. But, they are not suitable for clinical applications owing to their high cost, large size. Also, their low pulse repetition rate (PRR) of few tens of hertz prevents them from being used in real-time PAT. So, there is a growing need for an imaging system capable of real-time imaging for various clinical applications. In this work, we are using a nanosecond pulsed laser diode as an excitation source and a clinical ultrasound imaging system to obtain the photoacoustic imaging. The excitation laser is ~803 nm in wavelength with energy of ~1.4 mJ per pulse. So far, the reported frame rate for photoacoustic imaging is only a few hundred Hertz. We have demonstrated up to 7000 frames per second framerate in photoacoustic imaging (B-mode) and measured the flow rate of fast moving obje ct. Phantom experiments were performed to test the fast imaging capability and measure the flow rate of ink solution inside a tube. This fast photoacoustic imaging can be used for various clinical applications including cardiac related problems, where the blood flow rate is quite high, or other dynamic studies.

  8. High frame-rate, large field wavefront sensor

    SciTech Connect

    Avicola, K.; Salmon, J.T.; Brase, J.; Waltjen, K.; Presta, R. ); Balch, K.S. )

    1992-03-01

    A two-stage intensified 192 {times} 239 pixel imager developed by Eastman Kodak for motion analysis was used to construct a 1 kHz frame-rate Hartmann wavefront sensor. The sensor uses a monolithic array of lenslets with a focal length that is adjusted by an index fluid between the convex surface and an optical flat. The accuracy of the calculated centroid position, which is related to wavefront measurement accuracy, was obtained as a function of spot power and spot size. The sensor was then dynamically tested at a 1 kHz frame-rate with a 9 {times} 9 lenslet array and a fast steering mirror, which swept a plane wavefront across the wavefront sensor. An 8 cm diameter subaperture will provide a return signal (589 nm) level of about 1000 photons/ms using the AVLIS 1 kW laser (stretched pulse) as guide star source, which is sufficient to yield a wavefront measurement of better than {gamma}/10 rms. If an area of 6 {times} 6 pixels per Hartmann spot were allocated, this wavefront sensor could support a 32 {times} 32, or 1024, element deformable mirror.

  9. Design and construction of a high frame rate imaging system

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Waugaman, John L.; Liu, Anjun; Lu, Jian-Yu

    2002-05-01

    A new high frame rate imaging method has been developed recently [Jian-yu Lu, ``2D and 3D high frame rate imaging with limited diffraction beams,'' IEEE Trans. Ultrason. Ferroelectr. Freq. Control 44, 839-856 (1997)]. This method may have a clinical application for imaging of fast moving objects such as human hearts, velocity vector imaging, and low-speckle imaging. To implement the method, an imaging system has been designed. The system consists of one main printed circuit board (PCB) and 16 channel boards (each channel board contains 8 channels), in addition to a set-top box for connections to a personal computer (PC), a front panel board for user control and message display, and a power control and distribution board. The main board contains a field programmable gate array (FPGA) and controls all channels (each channel has also an FPGA). We will report the analog and digital circuit design and simulations, multiplayer PCB designs with commercial software (Protel 99), PCB signal integrity testing and system RFI/EMI shielding, and the assembly and construction of the entire system. [Work supported in part by Grant 5RO1 HL60301 from NIH.

  10. Frame rate free image velocimetry for microfluidic devices

    PubMed Central

    Keinan, Eliezer; Ezra, Elishai; Nahmias, Yaakov

    2013-01-01

    Here, we introduce Streamline Image Velocimetry, a method to derive fluid velocity fields in fully developed laminar flow from long-exposure images of streamlines. Streamlines confine streamtubes, in which the volumetric flow is constant for incompressible fluid. Using an explicit analytical solution as a boundary condition, velocity fields and emerging properties such as shear force and pressure can be quantified throughout. Numerical and experimental validations show a high correlation between anticipated and measured results, with R2 > 0.91. We report spatial resolution of 2 μm in a flow rate of 0.15 m/s, resolution that can only be achieved with 75 kHz frame rate in traditional particle tracking velocimetry. PMID:24023394

  11. Origins of the Kilohertz and Horizontal Branch QPOs in the Z Sources

    NASA Astrophysics Data System (ADS)

    Lamb, F. K.; Miller, M. C.; Psaltis, D.

    1999-04-01

    The frequency relationships observed between the upper and lower kilohertz QPOs and the ~ 10--60 Hz horizontal branch oscillations (HBOs) in the Z sources are important indicators of the mechanisms that produce them. We show that in the sonic point model of the kilohertz QPOs, the frequency separation between them is approximately equal to the stellar spin frequency nu_spin , but generally differs from nu_spin and varies with the mass accretion rate. For plausible models of the inner accretion disk, the frequency separation decreases with increasing accretion rate, in quantitative agreement with the variation of the frequency separation observed in Sco X-1. If the moments of inertia of neutron stars have the sizes expected theoretically and their spin frequencies in the Z sources are approximately equal to the frequency separation of the kilohertz QPOs, the Lense-Thirring precession model of the HBOs can account for the frequencies of the HBOs only if the HBO frequency is at least four times the precession frequency. Moreover, the correlation observed between the frequencies of the HBO and the upper kilohertz QPO cannot be accounted for in the Lense-Thirring precession model, even when the effects of classical precession are taken into account. In contrast, the magnetospheric beat-frequency model of the HBOs predicts a power-law relation between HBO frequency and upper kilohertz QPO frequency that is consistent with the relation observed, if the frequency of the upper kilohertz QPO is an orbital frequency in the inner disk. The Z-source magnetic fields inferred from the model are ~ 10(9) --10(10) G.

  12. Visible light communication using mobile-phone camera with data rate higher than frame rate.

    PubMed

    Chow, Chi-Wai; Chen, Chung-Yen; Chen, Shih-Hao

    2015-10-01

    Complementary Metal-Oxide-Semiconductor (CMOS) image sensors are widely used in mobile-phone and cameras. Hence, it is attractive if these image sensors can be used as the visible light communication (VLC) receivers (Rxs). However, using these CMOS image sensors are challenging. In this work, we propose and demonstrate a VLC link using mobile-phone camera with data rate higher than frame rate of the CMOS image sensor. We first discuss and analyze the features of using CMOS image sensor as VLC Rx, including the rolling shutter effect, overlapping of exposure time of each row of pixels, frame-to-frame processing time gap, and also the image sensor "blooming" effect. Then, we describe the procedure of synchronization and demodulation. This includes file format conversion, grayscale conversion, column matrix selection avoiding blooming, polynomial fitting for threshold location. Finally, the evaluation of bit-error-rate (BER) is performed satisfying the forward error correction (FEC) limit. PMID:26480122

  13. GPU accelerated processing of astronomical high frame-rate videosequences

    NASA Astrophysics Data System (ADS)

    Vítek, Stanislav; Švihlík, Jan; Krasula, Lukáš; Fliegel, Karel; Páta, Petr

    2015-09-01

    Astronomical instruments located around the world are producing an incredibly large amount of possibly interesting scientific data. Astronomical research is expanding into large and highly sensitive telescopes. Total volume of data rates per night of operations also increases with the quality and resolution of state-of-the-art CCD/CMOS detectors. Since many of the ground-based astronomical experiments are placed in remote locations with limited access to the Internet, it is necessary to solve the problem of the data storage. It mostly means that current data acquistion, processing and analyses algorithm require review. Decision about importance of the data has to be taken in very short time. This work deals with GPU accelerated processing of high frame-rate astronomical video-sequences, mostly originating from experiment MAIA (Meteor Automatic Imager and Analyser), an instrument primarily focused to observing of faint meteoric events with a high time resolution. The instrument with price bellow 2000 euro consists of image intensifier and gigabite ethernet camera running at 61 fps. With resolution better than VGA the system produces up to 2TB of scientifically valuable video data per night. Main goal of the paper is not to optimize any GPU algorithm, but to propose and evaluate parallel GPU algorithms able to process huge amount of video-sequences in order to delete all uninteresting data.

  14. Effects of frame rate and image resolution on pulse rate measured using multiple camera imaging photoplethysmography

    NASA Astrophysics Data System (ADS)

    Blackford, Ethan B.; Estepp, Justin R.

    2015-03-01

    Non-contact, imaging photoplethysmography uses cameras to facilitate measurements including pulse rate, pulse rate variability, respiration rate, and blood perfusion by measuring characteristic changes in light absorption at the skin's surface resulting from changes in blood volume in the superficial microvasculature. Several factors may affect the accuracy of the physiological measurement including imager frame rate, resolution, compression, lighting conditions, image background, participant skin tone, and participant motion. Before this method can gain wider use outside basic research settings, its constraints and capabilities must be well understood. Recently, we presented a novel approach utilizing a synchronized, nine-camera, semicircular array backed by measurement of an electrocardiogram and fingertip reflectance photoplethysmogram. Twenty-five individuals participated in six, five-minute, controlled head motion artifact trials in front of a black and dynamic color backdrop. Increasing the input channel space for blind source separation using the camera array was effective in mitigating error from head motion artifact. Herein we present the effects of lower frame rates at 60 and 30 (reduced from 120) frames per second and reduced image resolution at 329x246 pixels (one-quarter of the original 658x492 pixel resolution) using bilinear and zero-order downsampling. This is the first time these factors have been examined for a multiple imager array and align well with previous findings utilizing a single imager. Examining windowed pulse rates, there is little observable difference in mean absolute error or error distributions resulting from reduced frame rates or image resolution, thus lowering requirements for systems measuring pulse rate over sufficient length time windows.

  15. Characterization of an infrared detector for high frame rate thermography

    NASA Astrophysics Data System (ADS)

    Fruehmann, R. K.; Crump, D. A.; Dulieu-Barton, J. M.

    2013-10-01

    The use of a commercially available photodetector based infrared thermography system, operating in the 2-5 µm range, for high frame rate imaging of temperature evolutions in solid materials is investigated. Infrared photodetectors provide a very fast and precise means of obtaining temperature evolutions over a wide range of science and engineering applications. A typical indium antimonide detector will have a thermal resolution of around 4 mK for room temperature measurements, with a noise threshold around 15 to 20 mK. However the precision of the measurement is dependent on the integration time (akin to exposure time in conventional photography). For temperature evolutions that occur at a moderate rate the integration time can be relatively long, enabling a large signal to noise ratio. A matter of increasing importance in engineering is the behaviour of materials at high strain rates, such as those experienced in impact, shock and ballistic loading. The rapid strain evolution in the material is usually accompanied by a temperature change. The temperature change will affect the material constitutive properties and hence it is important to capture both the temperature and the strain evolutions to provide a proper constitutive law for the material behaviour. The present paper concentrates on the capture of the temperature evolutions, which occur at such rates that rule out the use of contact sensors such as thermocouples and electrical resistance thermometers, as their response times are too slow. Furthermore it is desirable to have an indication of the temperature distribution over a test specimen, hence the full-field approach of IRT is investigated. The paper explores the many hitherto unaddressed challenges of IRT when employed at high speed. Firstly the images must be captured at high speeds, which means reduced integration times and hence a reduction in the signal to noise ratio. Furthermore, to achieve the high image capture rates the detector array must be

  16. Kilohertz Quasi-Periodic Oscillation Peak Separation Is Not Constant in Scorpius X-1

    NASA Astrophysics Data System (ADS)

    van der Klis, Michiel; Wijnands, Rudy A. D.; Horne, Keith; Chen, Wan

    1997-06-01

    We report on a series of 20, ~105 counts s-1, 0.125 ms time-resolution Rossi X-Ray Timing Explorer observations of the Z-source and low-mass X-ray binary Scorpius X-1. Twin kilohertz quasi-periodic oscillation (QPO) peaks are obvious in nearly all observations. We find that the peak separation is not constant, as expected in some beat-frequency models, but instead varies from ~310 to ~230 Hz when the centroid frequency of the higher frequency peak varies from ~875 to ~1085 Hz. We detect none of the additional QPO peaks at higher frequencies predicted in the photon bubble model (PBM), with best-case upper limits on the peaks' power ratio of 0.025. We do detect, simultaneously with the kilohertz QPO, additional QPO peaks near 45 and 90 Hz whose frequency increases with mass accretion rate. We interpret these as first and second harmonics of the so-called horizontal-branch oscillations that are well known from other Z-sources and usually interpreted in terms of the magnetospheric beat-frequency model (BFM). We conclude that the magnetospheric BFM and the PBM are now unlikely to explain the kilohertz QPO in Sco X-1. In order to succeed in doing so, any BFM involving the neutron star spin (unseen in Sco X-1) will have to postulate at least one additional unseen frequency, beating with the spin to produce one of the kilohertz peaks.

  17. High frame rate photoacoustic computed tomography using coded excitation

    NASA Astrophysics Data System (ADS)

    Azuma, Masataka; Zhang, Haichong K.; Kondo, Kengo; Namita, Takeshi; Yamakawa, Makoto; Shiina, Tsuyoshi

    2015-03-01

    Photoacoustic Computed Tomography (PACT) records signals from a wide range of angles to achieve uniform, highresolution images. A high-power laser is generally used for PACT, but the long acquisition time with a single probe is a problem due to the low pulse-repetition frequency (PRF). For PACT, this degrades image resolution and contrast because it is hard to scan with a small step interval. Moreover, in vivo measurement requires a fast image acquisition system to avoid motion artifacts. The problem can be resolved by using a high PRF laser, which provides only weak energy. Averaging measured signals many times can mitigate the low signal-to-noise issue, but the PRF is restricted by the acoustic time of flight, so this is a new source of measurement time increase. Here, we present the coded-excitation approach, which we previously proposed for linear scanning, to increase the PACT frame rate. Coded excitation irradiates temporally encoded pulses and enhances the signal amplitude through decoding. The PRF is thus not restricted to acoustic time of flight. Consequently, acquisition time can be shortened by increasing PRF, and the SNR increases for the same measurement time. To validate the proposed idea, we conducted experiments using a high PRF laser with a revolving motor and compared the performance of coded excitation to that of averaging. Results demonstrated that the contamination of a signal acquired from different angles was negligible, and that the scanning pitch was remarkably improved because the start point of decoding can be set in any code in the periodic sequence.

  18. Data rate management and real time operation: recursive adaptive frame integration of limited data

    NASA Astrophysics Data System (ADS)

    Rafailov, Michael K.

    2006-08-01

    Recursive Limited Frame Integration was proposed as a way to improve frame integration performance and mitigate issues related to high data rate needed to support conventional frame integration. The technique uses two thresholds -one tuned for optimum probability of detection, the other to manage required false alarm rate, and places integration process between those thresholds. This configuration allows a non-linear integration process that, along with Signal-to-Noise Ratio (SNR) gain, provides system designers more capability where cost, weight, or power considerations limit system data rate, processing, or memory capability. However, Recursive Frame Integration Limited may have performance issues when single-frame SNR is really low. Recursive Adaptive Limited Frame Integration was proposed as a means to improve limited integration performance with really low single-frame SNR. It combines the benefits of nonlinear recursive limited frame integration and adaptive thresholds with a kind of conventional frame integration. Adding the third threshold may help in managing real time operations. In the paper the Recursive Frame Integration is presented in form of multiple parallel recursive integration. Such an approach can help not only in data rate management but in mitigation of low single frame SNR issue for Recursive Integration as well as in real time operations with frame integration.

  19. Adaptation of hidden Markov models for recognizing speech of reduced frame rate.

    PubMed

    Lee, Lee-Min; Jean, Fu-Rong

    2013-12-01

    The frame rate of the observation sequence in distributed speech recognition applications may be reduced to suit a resource-limited front-end device. In order to use models trained using full-frame-rate data in the recognition of reduced frame-rate (RFR) data, we propose a method for adapting the transition probabilities of hidden Markov models (HMMs) to match the frame rate of the observation. Experiments on the recognition of clean and noisy connected digits are conducted to evaluate the proposed method. Experimental results show that the proposed method can effectively compensate for the frame-rate mismatch between the training and the test data. Using our adapted model to recognize the RFR speech data, one can significantly reduce the computation time and achieve the same level of accuracy as that of a method, which restores the frame rate using data interpolation. PMID:23757520

  20. Frame rate up conversion via Bayesian motion estimation

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Ma, Siwei; Gao, Wen

    2010-07-01

    In this paper, a novel block-based motion compensated frame interpolation (MCI) algorithm is proposed to enhance the temporal resolution of video sequences. We formulated motion estimation into MAP framework, and solved it via Bayesian belief propagation. By effectively incorporating a priori knowledge of the motion field and optimizing the whole motion field synchronously, it could derive more accurate motion vectors than traditional methods. Finally, adaptive overlapped block motion compensation (OBMC) is used to reduce blocking artifacts. Experimental results show that the proposed method outperforms other methods in both objective and subjective quality.

  1. A study of video frame rate on the perception of moving imagery detail

    NASA Technical Reports Server (NTRS)

    Haines, Richard F.; Chuang, Sherry L.

    1993-01-01

    The rate at which each frame of color moving video imagery is displayed was varied in small steps to determine what is the minimal acceptable frame rate for life scientists viewing white rats within a small enclosure. Two, twenty five second-long scenes (slow and fast animal motions) were evaluated by nine NASA principal investigators and animal care technicians. The mean minimum acceptable frame rate across these subjects was 3.9 fps both for the slow and fast moving animal scenes. The highest single trial frame rate averaged across all subjects for the slow and the fast scene was 6.2 and 4.8, respectively. Further research is called for in which frame rate, image size, and color/gray scale depth are covaried during the same observation period.

  2. The effects of frame rate and resolution on users playing first person shooter games

    NASA Astrophysics Data System (ADS)

    Claypool, Mark; Claypool, Kajal; Damaa, Feissal

    2006-01-01

    The rates and resolutions for frames rendered in a computer game directly impact the player performance, influencing both the overall game playability and the game's enjoyability. Insights into the effects of frame rates and resolutions can guide users in their choice for game settings and new hardware purchases, and inform system designers in their development of new hardware, especially for embedded devices that often must make tradeoffs between resolution and frame rate. While there have been studies detailing the effects of frame rate and resolution on streaming video and other multimedia applications, to the best of our knowledge, there have been no studies quantifying the effects of frame rate and resolution on user performance for computer games. This paper presents results of a carefully designed user study that measures the impact of frame rate and frame resolution on user performance in a first person shooter game. Contrary to previous results for streaming video, frame rate has a marked impact on both player performance and game enjoyment while resolution has little impact on performance and some impact on enjoyment.

  3. Frame rate of motion picture and its influence on speech perception

    NASA Astrophysics Data System (ADS)

    Nakazono, Kaoru

    1996-03-01

    The preservation of QoS for multimedia traffic through a data network is a difficult problem. We focus our attention on video frame rate and study its influence on speech perception. When sound and picture are discrepant (e.g., acoustic `ba' combined with visual `ga'), subjects perceive a different sound (such as `da'). This phenomenon is known as the McGurk effect. In this paper, the influence of degraded video frame rate on speech perception was studied. It was shown that when frame rate decreases, correct hearing is improved for discrepant stimuli and is degraded for congruent (voice and picture are the same) stimuli. Furthermore, we studied the case where lip closure was always captured by the synchronization of sampling time and lip position. In this case, frame rate has little effect on mishearing for congruent stimuli. For discrepant stimuli, mishearing is decreased with degraded frame rate. These results indicate that stiff motion of lips resulting from low frame rate cannot give enough labial information for speech perception. In addition, the effect of delaying the picture to correct for low frame rate was studied. The results, however, were not as definitive as expected because of compound effects related to the synchronization of sound and picture.

  4. From Laboratory to Practice: Neglected Issues in Implementing Frame-of-Reference Rate-Training.

    ERIC Educational Resources Information Center

    Hauenstein, Neil M. A.; Foti, Roseanne J.

    1989-01-01

    Data collected at two law enforcement agencies were used to address three specific issues concerning frame-of-reference rater training: (1) prototype-anchored rating system; (2) sensitivity and threshold analyses to identify idiosyncratic raters; and (3) areas of performance where supervisors and subordinates were likely to disagree on frame of…

  5. Reconstruction of high frame rate image sequences in biomechanical related areas.

    PubMed

    Costa, Monica; Soares, Salviano; Barroso, Joao

    2010-01-01

    Regular video cameras shoot normally at 25/30 frames per second (fps). Actually there are available in the market equipments that allow us to acquire video at 1.000.000 fps. When we observe a video sequence it becomes noticeable that great part of the information remains unchanged regardless of the bit rate or frame rate used. One origin of discontinuity in video signals is directly related to movement. Several areas use high frame rate images to analyze and comprehend certain events or effects, biomechanical engineering is one of them. Biomechanics engineering studies the mechanics of a living body, especially the forces exerted by muscles and gravity on the skeletal structure. Some examples are athlete assessment, were images are capture and then the acquired parameters are analyzed. This article describes a new methodology to decrease the space needed to store high frame rate image sequences in the specific case of biomechanical related areas. PMID:21095875

  6. The impact of cine EPID image acquisition frame rate on markerless soft-tissue tracking

    SciTech Connect

    Yip, Stephen Rottmann, Joerg; Berbeco, Ross

    2014-06-15

    Purpose: Although reduction of the cine electronic portal imaging device (EPID) acquisition frame rate through multiple frame averaging may reduce hardware memory burden and decrease image noise, it can hinder the continuity of soft-tissue motion leading to poor autotracking results. The impact of motion blurring and image noise on the tracking performance was investigated. Methods: Phantom and patient images were acquired at a frame rate of 12.87 Hz with an amorphous silicon portal imager (AS1000, Varian Medical Systems, Palo Alto, CA). The maximum frame rate of 12.87 Hz is imposed by the EPID. Low frame rate images were obtained by continuous frame averaging. A previously validated tracking algorithm was employed for autotracking. The difference between the programmed and autotracked positions of a Las Vegas phantom moving in the superior-inferior direction defined the tracking error (δ). Motion blurring was assessed by measuring the area change of the circle with the greatest depth. Additionally, lung tumors on 1747 frames acquired at 11 field angles from four radiotherapy patients are manually and automatically tracked with varying frame averaging. δ was defined by the position difference of the two tracking methods. Image noise was defined as the standard deviation of the background intensity. Motion blurring and image noise are correlated with δ using Pearson correlation coefficient (R). Results: For both phantom and patient studies, the autotracking errors increased at frame rates lower than 4.29 Hz. Above 4.29 Hz, changes in errors were negligible withδ < 1.60 mm. Motion blurring and image noise were observed to increase and decrease with frame averaging, respectively. Motion blurring and tracking errors were significantly correlated for the phantom (R = 0.94) and patient studies (R = 0.72). Moderate to poor correlation was found between image noise and tracking error with R −0.58 and −0.19 for both studies, respectively. Conclusions: Cine EPID

  7. The effects of framing and fear on ratings and impact of antimarijuana PSAs.

    PubMed

    Zimmerman, Rick S; Cupp, Pamela K; Abadi, Melissa; Donohew, R Lewis; Gray, Carla; Gordon, Leonard; Grossl, A Bailey

    2014-06-01

    A laboratory experiment, funded by the U.S. National Institutes of Health, involved 243 U.S. undergraduate students and employed a 2 (gain-framed vs. loss-framed) × 2 (high vs. low threat) plus control group pretest-posttest experimental design to assess the combined effects of frame (gain vs. loss) and level of threat of public service announcements (PSAs) about marijuana on attitudes, beliefs, and intentions related to marijuana, as well as the relationship of message condition to ratings of PSAs. Results suggest that loss-framed messages may lead to greater perceived threat, as well as reactance, and gain-framed messages may lead to a greater reduction in positive attitudes toward marijuana than loss-framed messages. Finally, frame and threat may interact in a complex way. Further research is suggested to replicate these findings. A substantial body of carefully crafted and systematic research studies examining both content and features of messages increasingly informs mass media prevention efforts, including the development of public service announcements (PSAs). Although the significance of messages on commercial broadcast stations may be diminishing with the increasing role and impact of new media, many of the basic questions addressed by this research are likely to apply across media channels. Nonetheless, important questions about what makes a message effective in changing an individual's attitudes or behavior remain to be answered. In this paper, the authors focus on two theoretically derived strategies that offer possibilities for developing persuasive messages: framing and threat. PMID:24502372

  8. Applying compressive sensing to TEM video: A substantial frame rate increase on any camera

    DOE PAGESBeta

    Stevens, Andrew; Kovarik, Libor; Abellan, Patricia; Yuan, Xin; Carin, Lawrence; Browning, Nigel D.

    2015-08-13

    One of the main limitations of imaging at high spatial and temporal resolution during in-situ transmission electron microscopy (TEM) experiments is the frame rate of the camera being used to image the dynamic process. While the recent development of direct detectors has provided the hardware to achieve frame rates approaching 0.1 ms, the cameras are expensive and must replace existing detectors. In this paper, we examine the use of coded aperture compressive sensing (CS) methods to increase the frame rate of any camera with simple, low-cost hardware modifications. The coded aperture approach allows multiple sub-frames to be coded and integratedmore » into a single camera frame during the acquisition process, and then extracted upon readout using statistical CS inversion. Here we describe the background of CS and statistical methods in depth and simulate the frame rates and efficiencies for in-situ TEM experiments. Depending on the resolution and signal/noise of the image, it should be possible to increase the speed of any camera by more than an order of magnitude using this approach.« less

  9. Applying compressive sensing to TEM video: A substantial frame rate increase on any camera

    SciTech Connect

    Stevens, Andrew; Kovarik, Libor; Abellan, Patricia; Yuan, Xin; Carin, Lawrence; Browning, Nigel D.

    2015-08-13

    One of the main limitations of imaging at high spatial and temporal resolution during in-situ transmission electron microscopy (TEM) experiments is the frame rate of the camera being used to image the dynamic process. While the recent development of direct detectors has provided the hardware to achieve frame rates approaching 0.1 ms, the cameras are expensive and must replace existing detectors. In this paper, we examine the use of coded aperture compressive sensing (CS) methods to increase the frame rate of any camera with simple, low-cost hardware modifications. The coded aperture approach allows multiple sub-frames to be coded and integrated into a single camera frame during the acquisition process, and then extracted upon readout using statistical CS inversion. Here we describe the background of CS and statistical methods in depth and simulate the frame rates and efficiencies for in-situ TEM experiments. Depending on the resolution and signal/noise of the image, it should be possible to increase the speed of any camera by more than an order of magnitude using this approach.

  10. Dependence of Kilohertz Quasi-periodic Oscillation Properties on the Normal-Branch Oscillation Phase in Scorpius X-1

    NASA Astrophysics Data System (ADS)

    Yu, Wenfei; van der Klis, Michiel; Jonker, Peter G.

    2001-09-01

    We analyzed Rossi X-Ray Timing Explorer data of Scorpius X-1, which show kilohertz quasi-periodic oscillations (QPOs) and the ~6-8 Hz normal-branch oscillation (NBO) simultaneously. Using power spectra of 0.03-0.5 s data segments, we find that both the upper kilohertz QPO frequency ν2 and the ratio of lower to upper kilohertz QPO amplitude are anticorrelated to variations in the X-ray count rate taking place on the NBO timescale. The frequency dependence is similar to (but probably weaker than) that found on longer timescales, but the power ratio dependence is opposite to it. A model where radiative stresses on the disk material, modulated at the NBO frequency, lead to changes in ν2 can explain the data; this implies that some of the NBO flux changes originate from inside the inner disk radius. We discuss how these findings affect our understanding of kilohertz QPOs and of the low-frequency variability of low-mass X-ray binaries.

  11. 340-GHz 3D radar imaging test bed with 10-Hz frame rate

    NASA Astrophysics Data System (ADS)

    Robertson, Duncan A.; Marsh, Paul N.; Bolton, David R.; Middleton, Robert J. C.; Hunter, Robert I.; Speirs, Peter J.; Macfarlane, David G.; Cassidy, Scott L.; Smith, Graham M.

    2012-06-01

    We present a 340 GHz 3D radar imaging test bed with 10 Hz frame rate which enables the investigation of strategies for the detection of concealed threats in high risk public areas. The radar uses a wideband heterodyne scheme and fast-scanning optics to achieve moderate resolution volumetric data sets, over a limited field of view, of targets at moderate stand-off ranges. The high frame rate is achieved through the use of DDS chirp generation, fast galvanometer scanners and efficient processing which combines CPU multi-threading and GPU-based techniques, and is sufficiently fast to follow smoothly the natural motion of people.

  12. A novel read-out IC allowing microbolometers to operate with high frame rate

    NASA Astrophysics Data System (ADS)

    Zhou, Yun; Lv, Jian; Wang, LuXia; Que, LongCheng; Jiang, YaDong

    2012-10-01

    This paper presents a new Read_out IC (ROIC) that uses two shared capacitances for integral and sampling. At similar power consumption and chip area, this ROIC architecture achieves a higher frame rate compared with the conventional architecture. A 384×288 uncooled microbolometer focal plane array (FPA) based on the proposed circuit was implemented on silicon using a 0.5 μm CMOS technology. Measurements show the proposed architecture enables the frame rate increase of 6.8% using the same master clock.

  13. High frame-rate multichannel beam-scanning microscopy based on Lissajous trajectories

    PubMed Central

    Sullivan, Shane Z.; Muir, Ryan D.; Newman, Justin A.; Carlsen, Mark S.; Sreehari, Suhas; Doerge, Chris; Begue, Nathan J.; Everly, R. Michael; Bouman, Charles A.; Simpson, Garth J.

    2014-01-01

    A simple beam-scanning optical design based on Lissajous trajectory imaging is described for achieving up to kHz frame-rate optical imaging on multiple simultaneous data acquisition channels. In brief, two fast-scan resonant mirrors direct the optical beam on a circuitous trajectory through the field of view, with the trajectory repeat-time given by the least common multiplier of the mirror periods. Dicing the raw time-domain data into sub-trajectories combined with model-based image reconstruction (MBIR) 3D in-painting algorithms allows for effective frame-rates much higher than the repeat time of the Lissajous trajectory. Since sub-trajectory and full-trajectory imaging are simply different methods of analyzing the same data, both high-frame rate images with relatively low resolution and low frame rate images with high resolution are simultaneously acquired. The optical hardware required to perform Lissajous imaging represents only a minor modification to established beam-scanning hardware, combined with additional control and data acquisition electronics. Preliminary studies based on laser transmittance imaging and polarization-dependent second harmonic generation microscopy support the viability of the approach both for detection of subtle changes in large signals and for trace-light detection of transient fluctuations. PMID:25321997

  14. Seismic Load Rating Procedure for Welded Steel Frames Oligo-cyclic Fatigue

    SciTech Connect

    Ratiu, Mircea D.; Moisidis, Nicolae T.

    2004-07-01

    A dynamic load rating approach for seismic qualification of cold-formed steel welded frames is presented. Allowable seismic loads are developed from cyclic and monotonic tests of standard cold-formed steel components commonly used for piping and electrical raceway supports. The method permits simplified qualification of all connections of frame components through a single load comparison. Test input consists of rotation/cycles-to-failure data and monotonic moment/rotation data. Cyclic data are statistically evaluated to determine an acceptable maximum seismic rotation for the connection. The allowable seismic load is determined from the corresponding static rotation. Application to seismic qualification procedures is discussed. (authors)

  15. Is it valid to calculate the 3-kilohertz threshold by averaging 2 and 4 kilohertz?

    PubMed

    Gurgel, Richard K; Popelka, Gerald R; Oghalai, John S; Blevins, Nikolas H; Chang, Kay W; Jackler, Robert K

    2012-07-01

    Many guidelines for reporting hearing results use the threshold at 3 kilohertz (kHz), a frequency not measured routinely. This study assessed the validity of estimating the missing 3-kHz threshold by averaging the measured thresholds at 2 and 4 kHz. The estimated threshold was compared to the measured threshold at 3 kHz individually and when used in the pure-tone average (PTA) of 0.5, 1, 2, and 3 kHz in audiometric data from 2170 patients. The difference between the estimated and measured thresholds for 3 kHz was within ± 5 dB in 72% of audiograms, ± 10 dB in 91%, and within ± 20 dB in 99% (correlation coefficient r = 0.965). The difference between the PTA threshold using the estimated threshold compared with using the measured threshold at 3 kHz was within ± 5 dB in 99% of audiograms (r = 0.997). The estimated threshold accurately approximates the measured threshold at 3 kHz, especially when incorporated into the PTA. PMID:22301102

  16. The effects of scene content parameters, compression, and frame rate on the performance of analytics systems

    NASA Astrophysics Data System (ADS)

    Tsifouti, A.; Triantaphillidou, S.; Larabi, M. C.; Doré, G.; Bilissi, E.; Psarrou, A.

    2015-01-01

    In this investigation we study the effects of compression and frame rate reduction on the performance of four video analytics (VA) systems utilizing a low complexity scenario, such as the Sterile Zone (SZ). Additionally, we identify the most influential scene parameters affecting the performance of these systems. The SZ scenario is a scene consisting of a fence, not to be trespassed, and an area with grass. The VA system needs to alarm when there is an intruder (attack) entering the scene. The work includes testing of the systems with uncompressed and compressed (using H.264/MPEG-4 AVC at 25 and 5 frames per second) footage, consisting of quantified scene parameters. The scene parameters include descriptions of scene contrast, camera to subject distance, and attack portrayal. Additional footage, including only distractions (no attacks) is also investigated. Results have shown that every system has performed differently for each compression/frame rate level, whilst overall, compression has not adversely affected the performance of the systems. Frame rate reduction has decreased performance and scene parameters have influenced the behavior of the systems differently. Most false alarms were triggered with a distraction clip, including abrupt shadows through the fence. Findings could contribute to the improvement of VA systems.

  17. Novel driver method to improve ordinary CCD frame rate for high-speed imaging diagnosis

    NASA Astrophysics Data System (ADS)

    Luo, Tong-Ding; Li, Bin-Kang; Yang, Shao-Hua; Guo, Ming-An; Yan, Ming

    2016-06-01

    The use of ordinary Charge-coupled-Device (CCD) imagers for the analysis of fast physical phenomenon is restricted because of the low-speed performance resulting from their long output times. Even though the form of Intensified-CCD (ICCD), coupled with a gated image intensifier, has extended their use for high speed imaging, the deficiency remains to be solved that ICDD could record only one image in a single shot. This paper presents a novel driver method designed to significantly improve the ordinary interline CCD burst frame rate for high-speed photography. This method is based on the use of vertical registers as storage, so that a small number of additional frames comprised of reduced-spatial-resolution images obtained via a specific sampling operation can be buffered. Hence, the interval time of the received series of images is related to the exposure and vertical transfer times only and, thus, the burst frame rate can be increased significantly. A prototype camera based on this method is designed as part of this study, exhibiting a burst rate of up to 250,000 frames per second (fps) and a capacity to record three continuous images. This device exhibits a speed enhancement of approximately 16,000 times compared with the conventional speed, with a spatial resolution reduction of only 1/4.

  18. Videopanorama Frame Rate Requirements Derived from Visual Discrimination of Deceleration During Simulated Aircraft Landing

    NASA Technical Reports Server (NTRS)

    Furnstenau, Norbert; Ellis, Stephen R.

    2015-01-01

    In order to determine the required visual frame rate (FR) for minimizing prediction errors with out-the-window video displays at remote/virtual airport towers, thirteen active air traffic controllers viewed high dynamic fidelity simulations of landing aircraft and decided whether aircraft would stop as if to be able to make a turnoff or whether a runway excursion would be expected. The viewing conditions and simulation dynamics replicated visual rates and environments of transport aircraft landing at small commercial airports. The required frame rate was estimated using Bayes inference on prediction errors by linear FRextrapolation of event probabilities conditional on predictions (stop, no-stop). Furthermore estimates were obtained from exponential model fits to the parametric and non-parametric perceptual discriminabilities d' and A (average area under ROC-curves) as dependent on FR. Decision errors are biased towards preference of overshoot and appear due to illusionary increase in speed at low frames rates. Both Bayes and A - extrapolations yield a framerate requirement of 35 < FRmin < 40 Hz. When comparing with published results [12] on shooter game scores the model based d'(FR)-extrapolation exhibits the best agreement and indicates even higher FRmin > 40 Hz for minimizing decision errors. Definitive recommendations require further experiments with FR > 30 Hz.

  19. High frame rate photoacoustic imaging using multiple wave-length LED array light source

    NASA Astrophysics Data System (ADS)

    Agano, Toshitaka; Sato, Naoto; Nakatsuka, Hitoshi; Kitagawa, Kazuo; Hanaoka, Takamitsu; Morisono, Koji; Shigeta, Yusuke; Tanaka, Chizuyo

    2016-03-01

    We have successfully imaged photoacoustic differences of light absorbance between two images acquired by different wave-length LED array light source. Compared to photoacoustic imaging system using conventional solid-state laser light source, LED light source can be driven at higher frequency pulses, so we were able to get the subtraction image at higher frame rate that calculated from two images which were captured at each wave-length LED light pulse timing. We developed LED array light source which is composed to have two different wave-length chips, so each wave-length light pulse can be controlled and emitted freely. Thus LED array light source can be composed as multiple selectable wavelength more than two, and a various combination of subtraction image may become available at high frame rate.

  20. Backscanning step and stare imaging system with high frame rate and wide coverage.

    PubMed

    Sun, Chongshang; Ding, Yalin; Wang, Dejiang; Tian, Dapeng

    2015-06-01

    Step and stare imaging with staring arrays has become the main approach to realizing wide area coverage and high resolution imagery of potential targets. In this paper, a backscanning step and stare imaging system is described. Compared with traditional step and stare imaging systems, this system features a much higher frame rate by using a small-sized array. In order to meet the staring requirements, a fast steering mirror is employed to provide backscan motion to compensate for the image motion caused by the continuously scanning of the gimbal platform. According to the working principle, the control system is designed to step/stare the line of sight at a high frame rate with a high accuracy. Then a proof-of-concept backscanning step and stare imaging system is established with a CMOS camera. Finally, the modulation transfer function of the imaging system is measured by the slanted-edge method, and a quantitative analysis is made to evaluate the performance of image motion compensation. Experimental results confirm that both high frame rate and image quality improvement can be achieved by adopting this method. PMID:26192651

  1. Motion measurement of SAR antenna based on high frame rate camera

    NASA Astrophysics Data System (ADS)

    Li, Q.; Cao, R.; Feng, H.; Xu, Z.

    2015-03-01

    Synthetic Aperture Radar (SAR) is currently in the marine, agriculture, geology and other fields are widely used, while the SAR antenna is one of the most important subsystems. Performance of antenna has a significant impact on the SAR sensitivity, azimuth resolution, image blur degree and other parameter. To improve SAR resolution, SAR antenna is designed and fabricated according to flexible expandable style. However, the movement of flexible antenna will have a greater impact on accuracy of SAR systems, so the motion measurement of the flexible antenna is an urgent problem. This paper studied motion measurements method based on high frame rate camera, designed and completed a flexible antenna motion measurement experiment. In the experiment the main IMU and the sub IMU were placed at both ends of the cantilever, which is simulation of flexible antenna, the high frame rate camera was placed above the main IMU, and the imaging target was set on side of the sub IMU. When the cantilever motion occurs, IMU acquired spatial coordinates of cantilever movement in real-time, and high frame rate camera captured a series of target images, and then the images was input into JTC to obtain the cantilever motion coordinates. Through the contrast and analysis of measurement results, the measurement accuracy of flexible antenna motion is verified.

  2. Capsule endoscopy capture rate: Has 4 frames-per-second any impact over 2 frames-per-second?

    PubMed Central

    Fernandez-Urien, Ignacio; Carretero, Cristina; Borobio, Erika; Borda, Ana; Estevez, Emilio; Galter, Sara; Gonzalez-Suarez, Begoña; Gonzalez, Benito; Lujan, Marisol; Martinez, Jose Luis; Martínez, Vanessa; Menchén, Pedro; Navajas, Javier; Pons, Vicente; Prieto, Cesar; Valle, Julio

    2014-01-01

    AIM: To compare the current capsule and a new prototype at 2 and 4 frames-per-second, respectively, in terms of clinical and therapeutic impact. METHODS: One hundred patients with an indication for capsule endoscopy were included in the study. All procedures were performed with the new device (SB24). After an exhaustive evaluation of the SB24 videos, they were then converted to “SB2-like” videos for their evaluation. Findings, frames per finding, and clinical and therapeutic impact derived from video visualization were analyzed. Kappa index for interobserver agreement and χ2 and Student’s t tests for qualitative/quantitative variables, respectively, were used. Values of P under 0.05 were considered statistically significant. RESULTS: Eighty-nine out of 100 cases included in the study were ultimately included in the analysis. The SB24 videos detected the anatomical landmarks (Z-line and duodenal papilla) and lesions in more patients than the “SB2-like” videos. On the other hand, the SB24 videos detected more frames per landmark/lesion than the “SB2-like” videos. However, these differences were not statistically significant (P > 0.05). Both clinical and therapeutic impacts were similar between SB24 and “SB2-like” videos (K = 0.954). The time spent by readers was significantly higher for SB24 videos visualization (P < 0.05) than for “SB2-like” videos when all images captured by the capsule were considered. However, these differences become non-significant if we only take into account small bowel images (P > 0.05). CONCLUSION: More frames-per-second detect more landmarks, lesions, and frames per landmark/lesion, but is time consuming and has a very low impact on clinical and therapeutic management. PMID:25339834

  3. Technologies to develop a video camera with a frame rate higher than 100 Mfps

    NASA Astrophysics Data System (ADS)

    Vo Le, Cuong; Nguyen, H. D.; Dao, V. T. S.; Takehara, K.; Etoh, T. G.; Akino, T.; Nishi, K.; Kitamura, K.; Arai, T.; Maruyama, H.

    2008-11-01

    A feasibility study is presented for an image sensor capable of image capturing at 100 Mega-frames per second (Mfps). The basic structure of the sensor is the backside-illuminated ISIS, the in-situ storage image sensor, with slanted linear CCD memories, which has already achieved 1 Mfps with very high sensitivity. There are many potential technical barriers to further increase the frame rate up to 100 Mfps, such as traveling time of electrons within a pixel, Resistive-Capacitive (RC) delay in driving voltage transfer, heat generation, heavy electro-magnetic noises, etc. For each of the barriers, a countermeasure is newly proposed and the technical and practical possibility is examined mainly by simulations. The new technical proposals include a special wafer with n and p double epitaxial layers with smoothly changing doping profiles, a design method with curves, the thunderbolt bus lines, and digitalnoiseless image capturing by the ISIS with solely sinusoidal driving voltages. It is confirmed that the integration of these technologies is very promising to realize a practical image sensor with the ultra-high frame rate.

  4. A change detection approach to moving object detection in low frame-rate video

    SciTech Connect

    Porter, Reid B; Harvey, Neal R; Theiler, James P

    2009-01-01

    Moving object detection is of significant interest in temporal image analysis since it is a first step in many object identification and tracking applications. A key component in almost all moving object detection algorithms is a pixel-level classifier, where each pixel is predicted to be either part of a moving object or part of the background. In this paper we investigate a change detection approach to the pixel-level classification problem and evaluate its impact on moving object detection. The change detection approach that we investigate was previously applied to multi-and hyper-spectral datasets, where images were typically taken several days, or months apart. In this paper, we apply the approach to low-frame rate (1-2 frames per second) video datasets.

  5. Frame rate upconversion using pyramid structure and dense motion vector fields

    NASA Astrophysics Data System (ADS)

    Kim, Jun-Geon; Lee, Daeho

    2016-05-01

    We propose a frame rate upconversion (FRUC) method using pyramid structures (PS) and dense motion vector fields (MVFs). In FRUC processes, performance is dominantly dependent on motion compensation, thus motion vectors (MVs) must be precisely estimated. Variable sizes of blocks and large search ranges are needed to estimate the MVs of large objects and large movements; however, we use PS and dense MVFs to estimate MVs for various conditions. In the PS, we first estimate MVs on level 0, which is the most reduced image in the PS (L-1 times downsampling), and MVs on the high levels are estimated except for pixels having large corresponding MVs on the lower levels. Integration of MVFs for all levels is followed by a vector median filter to remove noises. Finally, a motion compensated frame is interpolated by weight-overlapped block motion compensation.

  6. High frame-rate resolution of cell division during Candida albicans filamentation.

    PubMed

    Thomson, Darren D; Berman, Judith; Brand, Alexandra C

    2016-03-01

    The commensal yeast, Candida albicans, is an opportunistic pathogen in humans and forms filaments called hyphae and pseudohyphae, in which cell division requires precise temporal and spatial control to produce mononuclear cell compartments. High-frame-rate live-cell imaging (1 frame/min) revealed that nuclear division did not occur across the septal plane. We detected the presence of nucleolar fragments that may be extrachromosomal molecules carrying the ribosomal RNA genes. Cells occasionally maintained multiple nucleoli, suggesting either polyploidy, multiple nuclei and/or aneuploidy of ChrR., while the migration pattern of sister nuclei differed between unbranched and branched hyphae. The presented movie challenges and extends previous concepts of C. albicans cell division. PMID:26854071

  7. Happiness and arousal: framing happiness as arousing results in lower happiness ratings for older adults.

    PubMed

    Bjalkebring, Par; Västfjäll, Daniel; Johansson, Boo E A

    2015-01-01

    Older adults have been shown to describe their happiness as lower in arousal when compared to younger adults. In addition, older adults prefer low arousal positive emotions over high arousal positive emotions in their daily lives. We experimentally investigated whether or not changing a few words in the description of happiness could influence a person's rating of their happiness. We randomly assigned 193 participants, aged 22-92 years, to one of three conditions (high arousal, low arousal, or control). In line with previous findings, we found that older participants rated their happiness lower when framed as high in arousal (i.e., ecstatic, to be bursting with positive emotions) and rated their happiness higher when framed as low in arousal (i.e., satisfied, to have a life filled with positive emotions). Younger adults remained uninfluenced by the manipulation. Our study demonstrates that arousal is essential to understanding ratings of happiness, and gives support to the notion that there are age differences in the preference for arousal. PMID:26097459

  8. Mach-Zehnder interferometry at framing rates of 10. 5--21 GHz

    SciTech Connect

    Houtman, H.; Legault, L.E.; Meyer, J.

    1987-03-15

    A simple beam splitter arrangement is used to divide a single ultrashort optical pulse into four beams of accurately known jitter-free delay. The 50-ps ruby laser beams are used in a Mach-Zehnder interferometer to produce four interferograms in one shot of the CO/sub 2/-laser-irradiated plasma at an interframe delay of 95 ps. Fringe straightness of <1/10 wave error is attained in all four frames by overlapping reference and scene beams precisely on the film while relaxing the constraint of the high spatial coherence necessary in shearing and folding shear interferometry. Such high fringe quality is required to record properly the observed fractional fringe shifts in a plasma of electron density up to n/sub e/ = 5 x 10/sup 18/ cm/sup -3/. The four-frame interferogram, recorded on Polaroid-type 667 film, is available immediately after the shot is taken. Neither a streak camera for recording timing sequences nor wavelength filters for rejection of plasma light was required. Simple rearrangement of optical components allows framing rates of 10.5 or 21.0 GHz.

  9. High Frame Rate Super Resolution Imaging Based on Ultrasound Synthetic Aperture Scheme

    NASA Astrophysics Data System (ADS)

    Wada, Takayuki; Ho, Yihsin; Okubo, Kan; Tagawa, Norio; Hirose, Yoshiyasu

    This study addresses the efficient extension of the Super resolution FM-Chirp correlation Method (SCM) to the framework of synthetic aperture imaging. The original SCM needs to transmit focused beams many times while changing frequency little by little toward each direction to extract the carrier phase information which is useful for super resolution imaging. This multiple transmitting and receiving increase the amount of processing and puts a strict limit on the frame rate. Therefore, we extend the SCM to the synthetic aperture version called the SA-SCM, and confirm its performance through simulations based on the finite element method.

  10. FPGA-based voltage and current dual drive system for high frame rate electrical impedance tomography.

    PubMed

    Khan, Shadab; Manwaring, Preston; Borsic, Andrea; Halter, Ryan

    2015-04-01

    Electrical impedance tomography (EIT) is used to image the electrical property distribution of a tissue under test. An EIT system comprises complex hardware and software modules, which are typically designed for a specific application. Upgrading these modules is a time-consuming process, and requires rigorous testing to ensure proper functioning of new modules with the existing ones. To this end, we developed a modular and reconfigurable data acquisition (DAQ) system using National Instruments' (NI) hardware and software modules, which offer inherent compatibility over generations of hardware and software revisions. The system can be configured to use up to 32-channels. This EIT system can be used to interchangeably apply current or voltage signal, and measure the tissue response in a semi-parallel fashion. A novel signal averaging algorithm, and 512-point fast Fourier transform (FFT) computation block was implemented on the FPGA. FFT output bins were classified as signal or noise. Signal bins constitute a tissue's response to a pure or mixed tone signal. Signal bins' data can be used for traditional applications, as well as synchronous frequency-difference imaging. Noise bins were used to compute noise power on the FPGA. Noise power represents a metric of signal quality, and can be used to ensure proper tissue-electrode contact. Allocation of these computationally expensive tasks to the FPGA reduced the required bandwidth between PC, and the FPGA for high frame rate EIT. In 16-channel configuration, with a signal-averaging factor of 8, the DAQ frame rate at 100 kHz exceeded 110 frames s (-1), and signal-to-noise ratio exceeded 90 dB across the spectrum. Reciprocity error was found to be for frequencies up to 1 MHz. Static imaging experiments were performed on a high-conductivity inclusion placed in a saline filled tank; the inclusion was clearly localized in the reconstructions obtained for both absolute current and voltage mode data. PMID:25376037

  11. High frame rate imaging using uncooled optical readout photomechanical IR sensor

    NASA Astrophysics Data System (ADS)

    Salerno, Jack P.

    2007-04-01

    Agiltron has produced a 280x240 photomechanical sensor array with an optical readout incorporating visible light cameras for both MWIR and LWIR imaging at speeds up to 1,000 frames per second. The photomechanical sensor is essentially a transducer that converts the image-induced temperature change into a mechanical deflection actuated by a micro-cantilevered beam. This defection is measured by an optical readout and converted into an electronic image. The photomechanical sensor requires no external drive for operation and therefore creates no bottleneck for readout data rate. It operates uncooled at widely varying ambient temperature. The use of off-the-shelf high speed visible light sensors allows for high frame rate imaging with no need for custom electronics or ROIC. Results on detection of rapid occurrence events, such as gunfire and rocket travel, are reported. The influence of detector sensitivity and time constant on the experimental imaging is discussed. Analysis of the frequency response of the photomechanical sensor is presented.

  12. A high frame rate, 16 million pixels, radiation hard CMOS sensor

    NASA Astrophysics Data System (ADS)

    Guerrini, N.; Turchetta, R.; Van Hoften, G.; Henderson, R.; McMullan, G.; Faruqi, A. R.

    2011-03-01

    CMOS sensors provide the possibility of designing detectors for a large variety of applications with all the benefits and flexibility of the widely used CMOS process. In this paper we describe a novel CMOS sensor designed for transmission electron microscopy. The overall design consists of a large 61 × 63 mm2 silicon area containing 16 million pixels arranged in a 4K × 4K array, with radiation hard geometry. All this is combined with a very fast readout, the possibility of region of interest (ROI) readout, pixel binning with consequent frame rate increase and a dynamic range close to 12 bits. The high frame rate has been achieved using 32 parallel analogue outputs each one operating at up to 20 MHz. Binning of pixels can be controlled externally and the flexibility of the design allows several possibilities, such as 2 × 2 or 4 × 4 binning. Other binning configurations where the number of rows and the number of columns are not equal, such as 2 × 1 or 2 × 4, are also possible. Having control of the CMOS design allowed us to optimise the pixel design, in particular with regard to its radiation hardness, and to make optimum choices in the design of other regions of the final sensor. An early prototype was also designed with a variety of geometries in order to optimise the readout structure and these are presented. The sensor was manufactured in a 0.35 μm standard CMOS process.

  13. Logic design and implementation of FPGA for a high frame rate ultrasound imaging system

    NASA Astrophysics Data System (ADS)

    Liu, Anjun; Wang, Jing; Lu, Jian-Yu

    2002-05-01

    Recently, a method has been developed for high frame rate medical imaging [Jian-yu Lu, ``2D and 3D high frame rate imaging with limited diffraction beams,'' IEEE Trans. Ultrason. Ferroelectr. Freq. Control 44(4), 839-856 (1997)]. To realize this method, a complicated system [multiple-channel simultaneous data acquisition, large memory in each channel for storing up to 16 seconds of data at 40 MHz and 12-bit resolution, time-variable-gain (TGC) control, Doppler imaging, harmonic imaging, as well as coded transmissions] is designed. Due to the complexity of the system, field programmable gate array (FPGA) (Xilinx Spartn II) is used. In this presentation, the design and implementation of the FPGA for the system will be reported. This includes the synchronous dynamic random access memory (SDRAM) controller and other system controllers, time sharing for auto-refresh of SDRAMs to reduce peak power, transmission and imaging modality selections, ECG data acquisition and synchronization, 160 MHz delay locked loop (DLL) for accurate timing, and data transfer via either a parallel port or a PCI bus for post image processing. [Work supported in part by Grant 5RO1 HL60301 from NIH.

  14. Influence of frame rate and image delay on virtual driving performance.

    PubMed

    Sudarsan, S P; Du, L Q; Cobb, P N; Yager, E S; Jacobus, C J

    1997-01-01

    The control and navigation of unmanned ground vehicles (UGVs) by humans requires a thorough understanding of the limitations in human perception and performance. Images of the external world recorded by cameras mounted on the UGV are presented as a video display to the operator, who then remotely manipulates the vehicle using a standard control. Operator performance is directly proportional to the computational complexity associated with the processing of video data. This work studies the effects of frame rate and image delay (lag) on remote driving performance. Experiments were conducted with five subjects using a driving simulator with a 1 dof force feedback steering wheel control. After sufficient training on the simulator, subjects drove a virtual car on a standard track under varying settings of frame rate and lag. Performance was measured by the duration to complete the course. Comparison of performance both within and between subjects showed characteristic driving patterns at different settings. Implications of the findings are discussed in relation to video data presentation for remote driving applications. PMID:9731360

  15. High frame-rate intravascular optical frequency-domain imaging in vivo

    PubMed Central

    Cho, Han Saem; Jang, Sun-Joo; Kim, Kyunghun; Dan-Chin-Yu, Alexey V.; Shishkov, Milen; Bouma, Brett E.; Oh, Wang-Yuhl

    2013-01-01

    Intravascular optical frequency-domain imaging (OFDI), a second-generation optical coherence tomography (OCT) technology, enables imaging of the three-dimensional (3D) microstructure of the vessel wall following a short and nonocclusive clear liquid flush. Although 3D vascular visualization provides a greater appreciation of the vessel wall and intraluminal structures, a longitudinal imaging pitch that is several times bigger than the optical imaging resolution of the system has limited true high-resolution 3D imaging, mainly due to the slow scanning speed of previous imaging catheters. Here, we demonstrate high frame-rate intravascular OFDI in vivo, acquiring images at a rate of 350 frames per second. A custom-built, high-speed, and high-precision fiber-optic rotary junction provided uniform and high-speed beam scanning through a custom-made imaging catheter with an outer diameter of 0.87 mm. A 47-mm-long rabbit aorta was imaged in 3.7 seconds after a short contrast agent flush. The longitudinal imaging pitch was 34 μm, comparable to the transverse imaging resolution of the system. Three-dimensional volume-rendering showed greatly enhanced visualization of tissue microstructure and stent struts relative to what is provided by conventional intravascular imaging speeds. PMID:24466489

  16. Correlations between Kilohertz Quasi-periodic Oscillations and Low-Frequency Features Attributed to Radial Oscillations and Diffusive Propagation in the Viscous Boundary Layer around a Neutron Star

    NASA Astrophysics Data System (ADS)

    Titarchuk, Lev; Osherovich, Vladimir

    1999-06-01

    We present a dimensional analysis of two characteristic timescales in the boundary layer where the disk adjusts to the rotating neutron star (NS). The boundary layer is treated as a transition region between the NS surface and the first Keplerian orbit. The radial transport of the angular momentum in this layer is controlled by a viscous force defined by the Reynolds number, which in turn is related to the mass accretion rate. We show that the observed low-Lorentzian frequency is associated with radial oscillations in the boundary layer, where the observed break frequency is determined by the characteristic diffusion time of the inward motion of the matter in the accretion flow. Predictions of our model regarding relations between those two frequencies and the frequencies of kilohertz quasi-periodic oscillations (kHz QPOs) compare favorably with recent observations of the source 4U 1728-34. This Letter contains a theoretical classification of kHz QPOs in NS binaries and the related low-frequency features. Thus, results concerning the relationship between the low-Lorentzian frequency of viscous oscillations and the break frequency are presented in the framework of our model of kHz QPOs viewed as Keplerian oscillations in a rotating frame of reference.

  17. Joint non-Gaussian denoising and superresolving of raw high frame rate videos.

    PubMed

    Jinli Suo; Yue Deng; Liheng Bian; Qionghai Dai

    2014-03-01

    High frame rate cameras capture sharp videos of highly dynamic scenes by trading off signal-noise-ratio and image resolution, so combinational super-resolving and denoising is crucial for enhancing high speed videos and extending their applications. The solution is nontrivial due to the fact that two deteriorations co-occur during capturing and noise is nonlinearly dependent on signal strength. To handle this problem, we propose conducting noise separation and super resolution under a unified optimization framework, which models both spatiotemporal priors of high quality videos and signal-dependent noise. Mathematically, we align the frames along temporal axis and pursue the solution under the following three criterion: 1) the sharp noise-free image stack is low rank with some missing pixels denoting occlusions; 2) the noise follows a given nonlinear noise model; and 3) the recovered sharp image can be reconstructed well with sparse coefficients and an over complete dictionary learned from high quality natural images. In computation aspects, we propose to obtain the final result by solving a convex optimization using the modern local linearization techniques. In the experiments, we validate the proposed approach in both synthetic and real captured data. PMID:24723520

  18. Algorithm for Automatic Behavior Quantification of Laboratory Mice Using High-Frame-Rate Videos

    NASA Astrophysics Data System (ADS)

    Nie, Yuman; Takaki, Takeshi; Ishii, Idaku; Matsuda, Hiroshi

    In this paper, we propose an algorithm for automatic behavior quantification in laboratory mice to quantify several model behaviors. The algorithm can detect repetitive motions of the fore- or hind-limbs at several or dozens of hertz, which are too rapid for the naked eye, from high-frame-rate video images. Multiple repetitive motions can always be identified from periodic frame-differential image features in four segmented regions — the head, left side, right side, and tail. Even when a mouse changes its posture and orientation relative to the camera, these features can still be extracted from the shift- and orientation-invariant shape of the mouse silhouette by using the polar coordinate system and adjusting the angle coordinate according to the head and tail positions. The effectiveness of the algorithm is evaluated by analyzing long-term 240-fps videos of four laboratory mice for six typical model behaviors: moving, rearing, immobility, head grooming, left-side scratching, and right-side scratching. The time durations for the model behaviors determined by the algorithm have detection/correction ratios greater than 80% for all the model behaviors. This shows good quantification results for actual animal testing.

  19. Image quality, tissue heating, and frame rate trade-offs in acoustic radiation force impulse imaging.

    PubMed

    Bouchard, Richard R; Dahl, Jeremy J; Hsu, Stephen J; Palmeri, Mark L; Trahey, Gregg E

    2009-01-01

    The real-time application of acoustic radiation force impulse (ARFI) imaging requires both short acquisition times for a single ARFI image and repeated acquisition of these frames. Due to the high energy of pulses required to generate appreciable radiation force, however, repeated acquisitions could result in substantial transducer face and tissue heating. We describe and evaluate several novel beam sequencing schemes which, along with parallel-receive acquisition, are designed to reduce acquisition time and heating. These techniques reduce the total number of radiation force impulses needed to generate an image and minimize the time between successive impulses. We present qualitative and quantitative analyses of the trade-offs in image quality resulting from the acquisition schemes. Results indicate that these techniques yield a significant improvement in frame rate with only moderate decreases in image quality. Tissue and transducer face heating resulting from these schemes is assessed through finite element method modeling and thermocouple measurements. Results indicate that heating issues can be mitigated by employing ARFI acquisition sequences that utilize the highest track-to-excitation ratio possible. PMID:19213633

  20. In vivo sub-femtoliter resolution photoacoustic microscopy with higher frame rates

    NASA Astrophysics Data System (ADS)

    Lee, Szu-Yu; Lai, Yu-Hung; Huang, Kai-Chih; Cheng, Yu-Hsiang; Tseng, Tzu-Fang; Sun, Chi-Kuang

    2015-10-01

    Microscopy based on non-fluorescent absorption dye staining is widely used in various fields of biomedicine for 400 years. Unlike its fluorescent counterpart, non-fluorescent absorption microscopy lacks proper methodologies to realize its in vivo applications with a sub-femtoliter 3D resolution. Regardless of the most advanced high-resolution photoacoustic microscopy, sub-femtoliter spatial resolution is still unattainable, and the imaging speed is relatively slow. In this paper, based on the two-photon photoacoustic mechanism, we demonstrated a in vivo label free laser-scanning photoacoustic imaging modality featuring high frame rates and sub-femtoliter 3D resolution simultaneously, which stands as a perfect solution to 3D high resolution non-fluorescent absorption microscopy. Furthermore, we first demonstrated in vivo label-free two-photon acoustic microscopy on the observation of non-fluorescent melanin distribution within mouse skin.

  1. Data compression techniques applied to high resolution high frame rate video technology

    NASA Technical Reports Server (NTRS)

    Hartz, William G.; Alexovich, Robert E.; Neustadter, Marc S.

    1989-01-01

    An investigation is presented of video data compression applied to microgravity space experiments using High Resolution High Frame Rate Video Technology (HHVT). An extensive survey of methods of video data compression, described in the open literature, was conducted. The survey examines compression methods employing digital computing. The results of the survey are presented. They include a description of each method and assessment of image degradation and video data parameters. An assessment is made of present and near term future technology for implementation of video data compression in high speed imaging system. Results of the assessment are discussed and summarized. The results of a study of a baseline HHVT video system, and approaches for implementation of video data compression, are presented. Case studies of three microgravity experiments are presented and specific compression techniques and implementations are recommended.

  2. Very high frame rate volumetric integration of depth images on mobile devices.

    PubMed

    Kähler, Olaf; Adrian Prisacariu, Victor; Yuheng Ren, Carl; Sun, Xin; Torr, Philip; Murray, David

    2015-11-01

    Volumetric methods provide efficient, flexible and simple ways of integrating multiple depth images into a full 3D model. They provide dense and photorealistic 3D reconstructions, and parallelised implementations on GPUs achieve real-time performance on modern graphics hardware. To run such methods on mobile devices, providing users with freedom of movement and instantaneous reconstruction feedback, remains challenging however. In this paper we present a range of modifications to existing volumetric integration methods based on voxel block hashing, considerably improving their performance and making them applicable to tablet computer applications. We present (i) optimisations for the basic data structure, and its allocation and integration; (ii) a highly optimised raycasting pipeline; and (iii) extensions to the camera tracker to incorporate IMU data. In total, our system thus achieves frame rates up 47 Hz on a Nvidia Shield Tablet and 910 Hz on a Nvidia GTX Titan XGPU, or even beyond 1.1 kHz without visualisation. PMID:26439825

  3. In vivo sub-femtoliter resolution photoacoustic microscopy with higher frame rates

    PubMed Central

    Lee, Szu-Yu; Lai, Yu-Hung; Huang, Kai-Chih; Cheng, Yu-Hsiang; Tseng, Tzu-Fang; Sun, Chi-Kuang

    2015-01-01

    Microscopy based on non-fluorescent absorption dye staining is widely used in various fields of biomedicine for 400 years. Unlike its fluorescent counterpart, non-fluorescent absorption microscopy lacks proper methodologies to realize its in vivo applications with a sub-femtoliter 3D resolution. Regardless of the most advanced high-resolution photoacoustic microscopy, sub-femtoliter spatial resolution is still unattainable, and the imaging speed is relatively slow. In this paper, based on the two-photon photoacoustic mechanism, we demonstrated a in vivo label free laser-scanning photoacoustic imaging modality featuring high frame rates and sub-femtoliter 3D resolution simultaneously, which stands as a perfect solution to 3D high resolution non-fluorescent absorption microscopy. Furthermore, we first demonstrated in vivo label-free two-photon acoustic microscopy on the observation of non-fluorescent melanin distribution within mouse skin. PMID:26487363

  4. High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

    NASA Astrophysics Data System (ADS)

    Villagómez-Hoyos, Carlos A.; Stuart, Matthias B.; Bechsgaard, Thor; Nielsen, Michael Bachmann; Jensen, Jørgen Arendt

    2016-04-01

    This work presents the first in vivo results of 2-D high frame rate vector velocity imaging for transthoracic cardiac imaging. Measurements are made on a healthy volunteer using the SARUS experimental ultrasound scanner connected to an intercostal phased-array probe. Two parasternal long-axis view (PLAX) are obtained, one centred at the aortic valve and another centred at the left ventricle. The acquisition sequence was composed of 3 diverging waves for high frame rate synthetic aperture flow imaging. For verification a phantom measurement is performed on a transverse straight 5 mm diameter vessel at a depth of 100 mm in a tissue-mimicking phantom. A flow pump produced a 2 ml/s constant flow with a peak velocity of 0.2 m/s. The average estimated flow angle in the ROI was 86.22° +/- 6.66° with a true flow angle of 90°. A relative velocity bias of -39% with a standard deviation of 13% was found. In-vivo acquisitions show complex flow patterns in the heart. In the aortic valve view, blood is seen exiting the left ventricle cavity through the aortic valve into the aorta during the systolic phase of the cardiac cycle. In the left ventricle view, blood flow is seen entering the left ventricle cavity through the mitral valve and splitting in two ways when approximating the left ventricle wall. The work presents 2-D velocity estimates on the heart from a non-invasive transthoracic scan. The ability of the method detecting flow regardless of the beam angle could potentially reveal a more complete view of the flow patterns presented on the heart.

  5. Ultrasonic acoustic levitation for fast frame rate X-ray protein crystallography at room temperature

    PubMed Central

    Tsujino, Soichiro; Tomizaki, Takashi

    2016-01-01

    Increasing the data acquisition rate of X-ray diffraction images for macromolecular crystals at room temperature at synchrotrons has the potential to significantly accelerate both structural analysis of biomolecules and structure-based drug developments. Using lysozyme model crystals, we demonstrated the rapid acquisition of X-ray diffraction datasets by combining a high frame rate pixel array detector with ultrasonic acoustic levitation of protein crystals in liquid droplets. The rapid spinning of the crystal within a levitating droplet ensured an efficient sampling of the reciprocal space. The datasets were processed with a program suite developed for serial femtosecond crystallography (SFX). The structure, which was solved by molecular replacement, was found to be identical to the structure obtained by the conventional oscillation method for up to a 1.8-Å resolution limit. In particular, the absence of protein crystal damage resulting from the acoustic levitation was carefully established. These results represent a key step towards a fully automated sample handling and measurement pipeline, which has promising prospects for a high acquisition rate and high sample efficiency for room temperature X-ray crystallography. PMID:27150272

  6. Ultrasonic acoustic levitation for fast frame rate X-ray protein crystallography at room temperature.

    PubMed

    Tsujino, Soichiro; Tomizaki, Takashi

    2016-01-01

    Increasing the data acquisition rate of X-ray diffraction images for macromolecular crystals at room temperature at synchrotrons has the potential to significantly accelerate both structural analysis of biomolecules and structure-based drug developments. Using lysozyme model crystals, we demonstrated the rapid acquisition of X-ray diffraction datasets by combining a high frame rate pixel array detector with ultrasonic acoustic levitation of protein crystals in liquid droplets. The rapid spinning of the crystal within a levitating droplet ensured an efficient sampling of the reciprocal space. The datasets were processed with a program suite developed for serial femtosecond crystallography (SFX). The structure, which was solved by molecular replacement, was found to be identical to the structure obtained by the conventional oscillation method for up to a 1.8-Å resolution limit. In particular, the absence of protein crystal damage resulting from the acoustic levitation was carefully established. These results represent a key step towards a fully automated sample handling and measurement pipeline, which has promising prospects for a high acquisition rate and high sample efficiency for room temperature X-ray crystallography. PMID:27150272

  7. SU-E-J-112: The Impact of Cine EPID Image Acquisition Frame Rate On Markerless Soft-Tissue Tracking

    SciTech Connect

    Yip, S; Rottmann, J; Berbeco, R

    2014-06-01

    Purpose: Although reduction of the cine EPID acquisition frame rate through multiple frame averaging may reduce hardware memory burden and decrease image noise, it can hinder the continuity of soft-tissue motion leading to poor auto-tracking results. The impact of motion blurring and image noise on the tracking performance was investigated. Methods: Phantom and patient images were acquired at a frame rate of 12.87Hz on an AS1000 portal imager. Low frame rate images were obtained by continuous frame averaging. A previously validated tracking algorithm was employed for auto-tracking. The difference between the programmed and auto-tracked positions of a Las Vegas phantom moving in the superior-inferior direction defined the tracking error (δ). Motion blurring was assessed by measuring the area change of the circle with the greatest depth. Additionally, lung tumors on 1747 frames acquired at eleven field angles from four radiotherapy patients are manually and automatically tracked with varying frame averaging. δ was defined by the position difference of the two tracking methods. Image noise was defined as the standard deviation of the background intensity. Motion blurring and image noise were correlated with δ using Pearson correlation coefficient (R). Results: For both phantom and patient studies, the auto-tracking errors increased at frame rates lower than 4.29Hz. Above 4.29Hz, changes in errors were negligible with δ<1.60mm. Motion blurring and image noise were observed to increase and decrease with frame averaging, respectively. Motion blurring and tracking errors were significantly correlated for the phantom (R=0.94) and patient studies (R=0.72). Moderate to poor correlation was found between image noise and tracking error with R -0.58 and -0.19 for both studies, respectively. Conclusion: An image acquisition frame rate of at least 4.29Hz is recommended for cine EPID tracking. Motion blurring in images with frame rates below 4.39Hz can substantially reduce the

  8. Modeling fault diagnosis as the activation and use of a frame system. [for pilot problem-solving rating

    NASA Technical Reports Server (NTRS)

    Smith, Philip J.; Giffin, Walter C.; Rockwell, Thomas H.; Thomas, Mark

    1986-01-01

    Twenty pilots with instrument flight ratings were asked to perform a fault-diagnosis task for which they had relevant domain knowledge. The pilots were asked to think out loud as they requested and interpreted information. Performances were then modeled as the activation and use of a frame system. Cognitive biases, memory distortions and losses, and failures to correctly diagnose the problem were studied in the context of this frame system model.

  9. High-Frame-Rate Echocardiography Using Coherent Compounding With Doppler-Based Motion-Compensation.

    PubMed

    Poree, Jonathan; Posada, Daniel; Hodzic, Amir; Tournoux, Francois; Cloutier, Guy; Garcia, Damien

    2016-07-01

    High-frame-rate ultrasonography based on coherent compounding of unfocused beams can potentially transform the assessment of cardiac function. As it requires successive waves to be combined coherently, this approach is sensitive to high-velocity tissue motion. We investigated coherent compounding of tilted diverging waves, emitted from a 2.5 MHz clinical phased array transducer. To cope with high myocardial velocities, a triangle transmit sequence of diverging waves is proposed, combined with tissue Doppler imaging to perform motion compensation (MoCo). The compound sequence with integrated MoCo was adjusted from simulations and was tested in vitro and in vivo. Realistic myocardial velocities were analyzed in an in vitro spinning disk with anechoic cysts. While a 8 dB decrease (no motion versus high motion) was observed without MoCo, the contrast-to-noise ratio of the cysts was preserved with the MoCo approach. With this method, we could provide high-quality in vivo B-mode cardiac images with tissue Doppler at 250 frames per second. Although the septum and the anterior mitral leaflet were poorly apparent without MoCo, they became well perceptible and well contrasted with MoCo. The septal and lateral mitral annulus velocities determined by tissue Doppler were concordant with those measured by pulsed-wave Doppler with a clinical scanner (r(2)=0.7,y=0.9 x+0.5,N=60) . To conclude, high-contrast echo cardiographic B-mode and tissue Doppler images can be obtained with diverging beams when motion compensation is integrated in the coherent compounding process. PMID:26863650

  10. Analysis of high frame rate readout circuit for near-infrared InGaAs focal plane array

    NASA Astrophysics Data System (ADS)

    Huang, Zhangcheng; Chen, Yu; Huang, Songlei; Fang, Jiaxiong

    2013-09-01

    High frame rate imaging for applications such as meteorological forecast, motion target tracking require high-speed Read-Out Integrated Circuit (ROIC). In order to achieve 10 KHz of frame rate, this paper analyzes the bandwidth of Capacitive-feedback Trans-Impedance Amplifier (CTIA) in ROIC which is the dominant bandwidth-limiting node when interfaced with large InGaAs detector pixel capacitance of about 10pF. A small-signal model is presented to study the relationship between integration capacitance, detector capacitance, transconductance and CTIA bandwidth. Calculation and simulation results show explicitly how the series resistance at the interface restricts the frame rate of Focal Plane Arrays (FPA). In order to achieve low-noise performance at a high frame rate, this paper describes an optimal solution in ROIC design. A prototype ROIC chip (DL7) has been fabricated with 0.5-μm mixed signal CMOS process and interfaced with InGaAs detector arrays. Test results show that frame rate is above 10 KHz and ROIC noise is around 270 e-, near identical to the design value.

  11. Performance of an LPD prototype detector at MHz frame rates under Synchrotron and FEL radiation

    NASA Astrophysics Data System (ADS)

    Koch, A.; Hart, M.; Nicholls, T.; Angelsen, C.; Coughlan, J.; French, M.; Hauf, S.; Kuster, M.; Sztuk-Dambietz, J.; Turcato, M.; Carini, G. A.; Chollet, M.; Herrmann, S. C.; Lemke, H. T.; Nelson, S.; Song, S.; Weaver, M.; Zhu, D.; Meents, A.; Fischer, P.

    2013-11-01

    A MHz frame rate X-ray area detector (LPD — Large Pixel Detector) is under development by the Rutherford Appleton Laboratory for the European XFEL. The detector will have 1 million pixels and allows analogue storage of 512 images taken at 4.5 MHz in the detector front end. The LPD detector has 500 μm thick silicon sensor tiles that are bump bonded to a readout ASIC. The ASIC's preamplifier provides relatively low noise at high speed which results in a high dynamic range of 105 photons over an energy range of 5-20 keV. Small scale prototypes of 32 × 256 pixels (LPD 2-Tile detector) and 256 × 256 pixels (LPD supermodule detector) are now available for X-ray tests. The performance of prototypes of the detector is reported for first tests under synchrotron radiation (PETRA III at DESY) and Free-Electron-Laser radiation (LCLS at SLAC). The initial performance of the detector in terms of signal range and noise, radiation hardness and spatial and temporal response are reported. The main result is that the 4.5 MHz sampling detection chain is reliably working, including the analogue on-chip memory concept. The detector is at least radiation hard up to 5 MGy at 12 keV. In addition the multiple gain concept has been demonstrated over a dynamic range to 104 at 12 keV with a readout noise equivalent to < 1 photon rms in its most sensitive mode.

  12. High-frame-rate intensified fast optically shuttered TV cameras with selected imaging applications

    SciTech Connect

    Yates, G.J.; King, N.S.P.

    1994-08-01

    This invited paper focuses on high speed electronic/electro-optic camera development by the Applied Physics Experiments and Imaging Measurements Group (P-15) of Los Alamos National Laboratory`s Physics Division over the last two decades. The evolution of TV and image intensifier sensors and fast readout fast shuttered cameras are discussed. Their use in nuclear, military, and medical imaging applications are presented. Several salient characteristics and anomalies associated with single-pulse and high repetition rate performance of the cameras/sensors are included from earlier studies to emphasize their effects on radiometric accuracy of electronic framing cameras. The Group`s test and evaluation capabilities for characterization of imaging type electro-optic sensors and sensor components including Focal Plane Arrays, gated Image Intensifiers, microchannel plates, and phosphors are discussed. Two new unique facilities, the High Speed Solid State Imager Test Station (HSTS) and the Electron Gun Vacuum Test Chamber (EGTC) arc described. A summary of the Group`s current and developmental camera designs and R&D initiatives are included.

  13. Accurate Angle Estimator for High-Frame-Rate 2-D Vector Flow Imaging.

    PubMed

    Villagomez Hoyos, Carlos Armando; Stuart, Matthias Bo; Hansen, Kristoffer Lindskov; Nielsen, Michael Bachmann; Jensen, Jorgen Arendt

    2016-06-01

    This paper presents a novel approach for estimating 2-D flow angles using a high-frame-rate ultrasound method. The angle estimator features high accuracy and low standard deviation (SD) over the full 360° range. The method is validated on Field II simulations and phantom measurements using the experimental ultrasound scanner SARUS and a flow rig before being tested in vivo. An 8-MHz linear array transducer is used with defocused beam emissions. In the simulations of a spinning disk phantom, a 360° uniform behavior on the angle estimation is observed with a median angle bias of 1.01° and a median angle SD of 1.8°. Similar results are obtained on a straight vessel for both simulations and measurements, where the obtained angle biases are below 1.5° with SDs around 1°. Estimated velocity magnitudes are also kept under 10% bias and 5% relative SD in both simulations and measurements. An in vivo measurement is performed on a carotid bifurcation of a healthy individual. A 3-s acquisition during three heart cycles is captured. A consistent and repetitive vortex is observed in the carotid bulb during systoles. PMID:27093598

  14. High resolution, high frame rate video technology development plan and the near-term system conceptual design

    NASA Technical Reports Server (NTRS)

    Ziemke, Robert A.

    1990-01-01

    The objective of the High Resolution, High Frame Rate Video Technology (HHVT) development effort is to provide technology advancements to remove constraints on the amount of high speed, detailed optical data recorded and transmitted for microgravity science and application experiments. These advancements will enable the development of video systems capable of high resolution, high frame rate video data recording, processing, and transmission. Techniques such as multichannel image scan, video parameter tradeoff, and the use of dual recording media were identified as methods of making the most efficient use of the near-term technology.

  15. Object of interest extraction in low-frame-rate image sequences and application to mobile mapping systems

    NASA Astrophysics Data System (ADS)

    Li, Peng; Wang, Cheng

    2012-06-01

    Here, we present a novel object of interest (OOI) extraction framework designed for low-frame-rate (LFR) image sequences, typically from mobile mapping systems (MMS). The proposed method integrates tracking and segmentation in a unified framework. We propose a novel object-shaped kernel-based scale-invariant mean shift algorithm to track the OOI through the LFR sequences and keep the temporal consistency. Then the well-known GrabCut approach for static image segmentation is generalized to the LFR sequences. We analyze the imaging geometry of the OOI in LFR sequences collected by the MMS and design a Kalman filter module to assist the proposed tracker. Extensive experimental results on real LFR sequences collected by VISAT™ MMS demonstrate that the proposed approach is robust to the challenges such as low frame rate, fast scaling, and large inter-frame displacement of the OOI.

  16. How Fast Is Your Body Motion? Determining a Sufficient Frame Rate for an Optical Motion Tracking System Using Passive Markers.

    PubMed

    Song, Min-Ho; Godøy, Rolf Inge

    2016-01-01

    This paper addresses how to determine a sufficient frame (sampling) rate for an optical motion tracking system using passive reflective markers. When using passive markers for the optical motion tracking, avoiding identity confusion between the markers becomes a problem as the speed of motion increases, necessitating a higher frame rate to avoid a failure of the motion tracking caused by marker confusions and/or dropouts. Initially, one might believe that the Nyquist-Shannon sampling rate estimated from the assumed maximal temporal variation of a motion (i.e. a sampling rate at least twice that of the maximum motion frequency) could be the complete solution to the problem. However, this paper shows that also the spatial distance between the markers should be taken into account in determining the suitable frame rate of an optical motion tracking with passive markers. In this paper, a frame rate criterion for the optical tracking using passive markers is theoretically derived and also experimentally verified using a high-quality optical motion tracking system. Both the theoretical and the experimental results showed that the minimum frame rate is proportional to the ratio between the maximum speed of the motion and the minimum spacing between markers, and may also be predicted precisely if the proportional constant is known in advance. The inverse of the proportional constant is here defined as the tracking efficiency constant and it can be easily determined with some test measurements. Moreover, this newly defined constant can provide a new way of evaluating the tracking algorithm performance of an optical tracking system. PMID:26967900

  17. How Fast Is Your Body Motion? Determining a Sufficient Frame Rate for an Optical Motion Tracking System Using Passive Markers

    PubMed Central

    Song, Min-Ho; Godøy, Rolf Inge

    2016-01-01

    This paper addresses how to determine a sufficient frame (sampling) rate for an optical motion tracking system using passive reflective markers. When using passive markers for the optical motion tracking, avoiding identity confusion between the markers becomes a problem as the speed of motion increases, necessitating a higher frame rate to avoid a failure of the motion tracking caused by marker confusions and/or dropouts. Initially, one might believe that the Nyquist-Shannon sampling rate estimated from the assumed maximal temporal variation of a motion (i.e. a sampling rate at least twice that of the maximum motion frequency) could be the complete solution to the problem. However, this paper shows that also the spatial distance between the markers should be taken into account in determining the suitable frame rate of an optical motion tracking with passive markers. In this paper, a frame rate criterion for the optical tracking using passive markers is theoretically derived and also experimentally verified using a high-quality optical motion tracking system. Both the theoretical and the experimental results showed that the minimum frame rate is proportional to the ratio between the maximum speed of the motion and the minimum spacing between markers, and may also be predicted precisely if the proportional constant is known in advance. The inverse of the proportional constant is here defined as the tracking efficiency constant and it can be easily determined with some test measurements. Moreover, this newly defined constant can provide a new way of evaluating the tracking algorithm performance of an optical tracking system. PMID:26967900

  18. Precise reconstruction of fast moving cardiac valve in high frame rate synthetic transmit aperture ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Suzuki, Mayumi; Ikeda, Teiichiro; Ishihara, Chizue; Takano, Shinta; Masuzawa, Hiroshi

    2016-04-01

    To diagnose heart valve incompetence, i.e., one of the most serious cardiac dysfunctions, it is essential to obtain images of fast-moving valves at high spatial and temporal resolution. Ultrasound synthetic transmit aperture (STA) imaging has the potential to achieve high spatial resolution by synthesizing multiple pre-beamformed images obtained with corresponding multiple transmissions. However, applying STA to fast-moving targets is difficult due to serious target deformation. We propose a high-frame-rate STA (fast STA) imaging method that uses a reduced number of transmission events needed for each image. Fast STA is expected to suppress deformation of moving targets; however, it may result in deteriorated spatial resolution. In this study, we conducted a simulation study to evaluate fast STA. We quantitatively evaluated the reduction in deformation and deterioration of spatial resolution with a model involving a radially moving valve at the maximum speed of 0.5 m/s. The simulated raw channel data of the valve phantom was processed with offline beamforming programs. We compared B-mode images obtained through single received-line in a transmission (SRT) method, STA, and fast STA. The results show that fast STA with four-times-reduced events is superior in reconstructing the original shape of the moving valve to other methods. The accuracy of valve location is 97 and 100% better than those with SRT and STA, respectively. The resolution deterioration was found to be below the annoyance threshold considering the improved performance of the shape reconstruction. The obtained results are promising for providing more precise diagnostic information on cardiovascular diseases.

  19. Higher-frame-rate ultrasound imaging with reduced cross-talk by combining a synthetic aperture and spatial coded excitation

    NASA Astrophysics Data System (ADS)

    Ishihara, Chizue; Ikeda, Teiichiro; Masuzawa, Hiroshi

    2016-04-01

    In recent clinical practice of ultrasound imaging, the importance of high-frame-rate imaging is growing. Simultaneous multiple transmission is one way to increase frame rate while maintaining a spatial resolution and signal-to-noise ratio. However, this technique has an inherent issue in that "cross-talk artifacts" appear between the multiple transmitted pulses. In this study, a novel method providing higher-frame-rate ultrasound imaging with reduced cross-talk by combining a synthetic aperture and spatial coded excitation is proposed. In the proposed method, two coded transmission beams are simultaneously excited during beam steering in the lateral direction. Parallel receive beamforming is then performed in the region around individual transmission beams. Decoding is carried out by using two beamformed signals from a region where laterally neighboring transmission beams overlap. All decoded beamformed signals are then synthesized coherently. The proposed method was evaluated using a simulated phantom image under the assumption of imaging with a general sector probe. Results showed that the method achieved twice the frame rate while maintaining image resolution (105%) and reducing cross-talk artifacts from -37 dB to less than -57 dB.

  20. A 3mpixel ROIC with 10μm pixel pitch and 120Hz frame rate digital output

    NASA Astrophysics Data System (ADS)

    Ilan, Elad; Shiloah, Niv; Elkind, Shimon; Dobromislin, Roman; Freiman, Willie; Zviagintsev, Alex; Nevo, Itzik; Cohen, Oren; Khinich, Fanny; Adin, Amnon; Talmor, Ron; Milstain, Yaakov

    2013-02-01

    A 1920x1536 matrix ROIC (Readout IC) for 10x10 μm2 P-on-N InSb photodiode array is reported. The ROIC features several conversion gain options implemented at the pixel level. A 2-by-2 pixel binning feature is implemented at the pixel level as well, improving SNR and enabling higher frame rates by a factor of four. A new column ADC is designed for low noise and low power consumption, while reaching 95 kSps sampling rate. Since 3840 column ADCs are integrated on chip, the total conversion rate is over 360Mpxl/sec. The ROIC achieves 120 Hz frame rate at the full format, with power consumption of less than 400mW. A high speed digital video interface is developed to output the required data bandwidth at a reasonable pin count.

  1. Full-Field Spectroscopy at Megahertz-frame-rates: Application of Coherent Time-Stretch Transform

    NASA Astrophysics Data System (ADS)

    DeVore, Peter Thomas Setsuda

    Outliers or rogue events are found extensively in our world and have incredible effects. Also called rare events, they arise in the distribution of wealth (e.g., Pareto index), finance, network traffic, ocean waves, and e-commerce (selling less of more). Interest in rare optical events exploded after the sighting of optical rogue waves in laboratory experiments at UCLA. Detecting such tail events in fast streams of information necessitates real-time measurements. The Coherent Time-Stretch Transform chirps a pulsed source of radiation so that its temporal envelope matches its spectral profile (analogous to the far field regime of spatial diffraction), and the mapped spectral electric field is slow enough to be captured by a real-time digitizer. Combining this technique with spectral encoding, the time stretch technique has enabled a new class of ultra-high performance spectrometers and cameras (30+ MHz), and analog-to-digital converters that have led to the discovery of optical rogue waves and detection of cancer cells in blood with one in a million sensitivity. Conventionally, the Coherent Time-Stretch Transform maps the spectrum into the temporal electric field, but the time-dilation process along with inherent fiber losses results in reduction of peak power and loss of sensitivity, a problem exacerbated by extremely narrow molecular linewidths. The loss issue notwithstanding, in many cases the requisite dispersive optical device is not available. By extending the Coherent Time-Stretch Transform to the temporal near field, I have demonstrated, for the first time, phase-sensitive absorption spectroscopy of a gaseous sample at millions of frames per second. As the Coherent Time-Stretch Transform may capture both near and far field optical waves, it is a complete spectro-temporal optical characterization tool. This is manifested as an amplitude-dependent chirp, which implies the ability to measure the complex refractive index dispersion at megahertz frame rates. This

  2. Reversible Nerve Conduction Block Using Kilohertz Frequency Alternating Current

    PubMed Central

    Kilgore, Kevin L.; Bhadra, Niloy

    2013-01-01

    Objectives The features and clinical applications of balanced-charge kilohertz frequency alternating currents (KHFAC) are reviewed. Preclinical studies of KHFAC block have demonstrated that it can produce an extremely rapid and reversible block of nerve conduction. Recent systematic analysis and experimentation utilizing KHFAC block has resulted in a significant increase in interest in KHFAC block, both scientifically and clinically. Materials and Methods We review the history and characteristics of KHFAC block, the methods used to investigate this type of block, the experimental evaluation of block, and the electrical parameters and electrode designs needed to achieve successful block. We then analyze the existing clinical applications of high frequency currents, comparing the early results with the known features of KHFAC block. Results Although many features of KHFAC block have been characterized, there is still much that is unknown regarding the response of neural structures to rapidly fluctuating electrical fields. The clinical reports to date do not provide sufficient information to properly evaluate the mechanisms that result in successful or unsuccessful treatment. Conclusions KHFAC nerve block has significant potential as a means of controlling nerve activity for the purpose of treating disease. However, early clinical studies in the use of high frequency currents for the treatment of pain have not been designed to elucidate mechanisms or allow direct comparisons to preclinical data. We strongly encourage the careful reporting of the parameters utilized in these clinical studies, as well as the development of outcome measures that could illuminate the mechanisms of this modality. PMID:23924075

  3. Sub-kilohertz laser linewidth narrowing using polarization spectroscopy.

    PubMed

    Torrance, Joshua S; Sparkes, Ben M; Turner, Lincoln D; Scholten, Robert E

    2016-05-30

    We identify several beneficial characteristics of polarization spectroscopy as an absolute atomic reference for frequency stabilization of lasers, and demonstrate sub-kilohertz laser spectral linewidth narrowing using polarization spectroscopy with high-bandwidth feedback. Polarization spectroscopy provides a highly dispersive velocity-selective absolute atomic reference based on frequency-dependent birefringence in an optically pumped atomic gas. The pumping process leads to dominance of the primary closed transition, suppressing closely-spaced subsidiary resonances which reduce the effective capture range for conventional atomic references. The locking signal is based on subtraction of two orthogonal polarization signals, reducing the effect of laser intensity noise to the shot noise limit. We measure noise-limited servo bandwidth comparable to that of a high-finesse optical cavity without the frequency limit or complexity imposed by optical modulation normally associated with high bandwidth laser frequency stabilization. We demonstrate narrowing to 600±100 Hz laser linewidth using the beatnote between two similarly locked external cavity diode lasers. PMID:27410068

  4. The effect of frame rate on the ability of experienced gait analysts to identify characteristics of gait from closed circuit television footage.

    PubMed

    Birch, Ivan; Vernon, Wesley; Burrow, Gordon; Walker, Jeremy

    2014-03-01

    Forensic gait analysis is increasingly being used as part of criminal investigations. A major issue is the quality of the closed circuit television (CCTV) footage used, particularly the frame rate which can vary from 25 frames per second to one frame every 4s. To date, no study has investigated the effect of frame rate on forensic gait analysis. A single subject was fitted with an ankle foot orthosis and recorded walking at 25 frames per second. 3D motion data were also collected, providing an absolute assessment of the gait characteristics. The CCTV footage was then edited to produce a set of eight additional pieces of footage, at various frame rates. Practitioners with knowledge of forensic gait analysis were recruited and instructed to record their observations regarding the characteristics of the subject's gait from the footage. They were sequentially sent web links to the nine pieces of footage, lowest frame rate first, and a simple observation recording form, over a period of 8 months. A sample-based Pearson product-moment correlation analysis of the results demonstrated a significant positive relationship between frame rate and scores (r=0.868, p=0.002). The results of this study show that frame rate affects the ability of experienced practitioners to identify characteristics of gait captured on CCTV footage. Every effort should therefore be made to ensure that CCTV footage likely to be used in criminal proceedings is captured at as high a frame rate as possible. PMID:24630327

  5. Parallel generation of uniform fine droplets at hundreds of kilohertz in a flow-focusing module

    PubMed Central

    Bardin, David; Kendall, Michael R.; Dayton, Paul A.; Lee, Abraham P.

    2013-01-01

    Droplet-based microfluidic systems enable a variety of biomedical applications from point-of-care diagnostics with third world implications, to targeted therapeutics alongside medical ultrasound, to molecular screening and genetic testing. Though these systems maintain the key advantage of precise control of the size and composition of the droplet as compared to conventional methods of production, the low rates at which droplets are produced limits translation beyond the laboratory setting. As well, previous attempts to scale up shear-based microfluidic systems focused on increasing the volumetric throughput and formed large droplets, negating many practical applications of emulsions such as site-specific therapeutics. We present the operation of a parallel module with eight flow-focusing orifices in the dripping regime of droplet formation for the generation of uniform fine droplets at rates in the hundreds of kilohertz. Elevating the capillary number to access dripping, generation of monodisperse droplets of liquid perfluoropentane in the parallel module exceeded 3.69 × 105 droplets per second, or 1.33 × 109 droplets per hour, at a mean diameter of 9.8 μm. Our microfluidic method offers a novel means to amass uniform fine droplets in practical amounts, for instance, to satisfy clinical needs, with the potential for modification to form massive amounts of more complex droplets. PMID:24404032

  6. Optical cell tracking analysis using a straight-forward approach to minimize processing time for high frame rate data

    NASA Astrophysics Data System (ADS)

    Seeto, Wen Jun; Lipke, Elizabeth Ann

    2016-03-01

    Tracking of rolling cells via in vitro experiment is now commonly performed using customized computer programs. In most cases, two critical challenges continue to limit analysis of cell rolling data: long computation times due to the complexity of tracking algorithms and difficulty in accurately correlating a given cell with itself from one frame to the next, which is typically due to errors caused by cells that either come close in proximity to each other or come in contact with each other. In this paper, we have developed a sophisticated, yet simple and highly effective, rolling cell tracking system to address these two critical problems. This optical cell tracking analysis (OCTA) system first employs ImageJ for cell identification in each frame of a cell rolling video. A custom MATLAB code was written to use the geometric and positional information of all cells as the primary parameters for matching each individual cell with itself between consecutive frames and to avoid errors when tracking cells that come within close proximity to one another. Once the cells are matched, rolling velocity can be obtained for further analysis. The use of ImageJ for cell identification eliminates the need for high level MATLAB image processing knowledge. As a result, only fundamental MATLAB syntax is necessary for cell matching. OCTA has been implemented in the tracking of endothelial colony forming cell (ECFC) rolling under shear. The processing time needed to obtain tracked cell data from a 2 min ECFC rolling video recorded at 70 frames per second with a total of over 8000 frames is less than 6 min using a computer with an Intel® Core™ i7 CPU 2.80 GHz (8 CPUs). This cell tracking system benefits cell rolling analysis by substantially reducing the time required for post-acquisition data processing of high frame rate video recordings and preventing tracking errors when individual cells come in close proximity to one another.

  7. Optical cell tracking analysis using a straight-forward approach to minimize processing time for high frame rate data.

    PubMed

    Seeto, Wen Jun; Lipke, Elizabeth Ann

    2016-03-01

    Tracking of rolling cells via in vitro experiment is now commonly performed using customized computer programs. In most cases, two critical challenges continue to limit analysis of cell rolling data: long computation times due to the complexity of tracking algorithms and difficulty in accurately correlating a given cell with itself from one frame to the next, which is typically due to errors caused by cells that either come close in proximity to each other or come in contact with each other. In this paper, we have developed a sophisticated, yet simple and highly effective, rolling cell tracking system to address these two critical problems. This optical cell tracking analysis (OCTA) system first employs ImageJ for cell identification in each frame of a cell rolling video. A custom MATLAB code was written to use the geometric and positional information of all cells as the primary parameters for matching each individual cell with itself between consecutive frames and to avoid errors when tracking cells that come within close proximity to one another. Once the cells are matched, rolling velocity can be obtained for further analysis. The use of ImageJ for cell identification eliminates the need for high level MATLAB image processing knowledge. As a result, only fundamental MATLAB syntax is necessary for cell matching. OCTA has been implemented in the tracking of endothelial colony forming cell (ECFC) rolling under shear. The processing time needed to obtain tracked cell data from a 2 min ECFC rolling video recorded at 70 frames per second with a total of over 8000 frames is less than 6 min using a computer with an Intel® Core™ i7 CPU 2.80 GHz (8 CPUs). This cell tracking system benefits cell rolling analysis by substantially reducing the time required for post-acquisition data processing of high frame rate video recordings and preventing tracking errors when individual cells come in close proximity to one another. PMID:27036782

  8. Multi-exposure laser speckle contrast imaging using a high frame rate CMOS sensor with a field programmable gate array.

    PubMed

    Sun, Shen; Hayes-Gill, Barrie R; He, Diwei; Zhu, Yiqun; Morgan, Stephen P

    2015-10-15

    A system has been developed in which multi-exposure laser speckle contrast imaging (LSCI) is implemented using a high frame rate CMOS imaging sensor chip. Processing is performed using a field programmable gate array (FPGA). The system allows different exposure times to be simulated by accumulating a number of short exposures. This has the advantage that the image acquisition time is limited by the maximum exposure time and that regulation of the illuminating light level is not required. This high frame rate camera has also been deployed to implement laser Doppler blood flow processing, enabling a direct comparison of multi-exposure laser speckle imaging and laser Doppler imaging (LDI) to be carried out using the same experimental data. Results from a rotating diffuser indicate that both multi-exposure LSCI and LDI provide a linear response to changes in velocity. This cannot be obtained using single-exposure LSCI, unless an appropriate model is used for correcting the response. PMID:26469570

  9. High-frame rate four dimensional optoacoustic tomography enables visualization of cardiovascular dynamics and mouse heart perfusion

    PubMed Central

    Deán-Ben, Xosé Luís; Ford, Steven James; Razansky, Daniel

    2015-01-01

    Functional imaging of mouse models of cardiac health and disease provides a major contribution to our fundamental understanding of the mammalian heart. However, imaging murine hearts presents significant challenges due to their small size and rapid heart rate. Here we demonstrate the feasibility of high-frame-rate, noninvasive optoacoustic imaging of the murine heart. The temporal resolution of 50 three-dimensional frames per second provides functional information at important phases of the cardiac cycle without the use of gating or other motion-reduction methods. Differentiation of the blood oxygenation state in the heart chambers was enabled by exploiting the wavelength dependence of optoacoustic signals. Real-time volumetric tracking of blood perfusion in the cardiac chambers was also evaluated using indocyanine green. Taken together, the newly-discovered capacities offer a unique tool set for in-vivo structural and functional imaging of the whole heart with high spatio-temporal resolution in all three dimensions. PMID:26130401

  10. Application of X-Y separable 2-D array beamforming for increased frame rate and energy efficiency in handheld devices.

    PubMed

    Owen, Kevin; Fuller, Michael; Hossack, John

    2012-07-01

    Two-dimensional arrays present significant beamforming computational challenges because of their high channel count and data rate. These challenges are even more stringent when incorporating a 2-D transducer array into a battery-powered hand-held device, placing significant demands on power efficiency. Previous work in sonar and ultrasound indicates that 2-D array beamforming can be decomposed into two separable line-array beamforming operations. This has been used in conjunction with frequency-domain phase-based focusing to achieve fast volume imaging. In this paper, we analyze the imaging and computational performance of approximate near-field separable beamforming for high-quality delay-and-sum (DAS) beamforming and for a low-cost, phase-rotation-only beamforming method known as direct-sampled in-phase quadrature (DSIQ) beamforming. We show that when high-quality time-delay interpolation is used, separable DAS focusing introduces no noticeable imaging degradation under practical conditions. Similar results for DSIQ focusing are observed. In addition, a slight modification to the DSIQ focusing method greatly increases imaging contrast, making it comparable to that of DAS, despite having a wider main lobe and higher side lobes resulting from the limitations of phase-only time-delay interpolation. Compared with non-separable 2-D imaging, up to a 20-fold increase in frame rate is possible with the separable method. When implemented on a smart-phone-oriented processor to focus data from a 60 x 60 channel array using a 40 x 40 aperture, the frame rate per C-mode volume slice increases from 16 to 255 Hz for DAS, and from 11 to 193 Hz for DSIQ. Energy usage per frame is similarly reduced from 75 to 4.8 mJ/ frame for DAS, and from 107 to 6.3 mJ/frame for DSIQ. We also show that the separable method outperforms 2-D FFT-based focusing by a factor of 1.64 at these data sizes. This data indicates that with the optimal design choices, separable 2-D beamforming can

  11. Application of X-Y Separable 2-D Array Beamforming for Increased Frame Rate and Energy Efficiency in Handheld Devices

    PubMed Central

    Owen, Kevin; Fuller, Michael I.; Hossack, John A.

    2015-01-01

    Two-dimensional arrays present significant beamforming computational challenges because of their high channel count and data rate. These challenges are even more stringent when incorporating a 2-D transducer array into a battery-powered hand-held device, placing significant demands on power efficiency. Previous work in sonar and ultrasound indicates that 2-D array beamforming can be decomposed into two separable line-array beamforming operations. This has been used in conjunction with frequency-domain phase-based focusing to achieve fast volume imaging. In this paper, we analyze the imaging and computational performance of approximate near-field separable beamforming for high-quality delay-and-sum (DAS) beamforming and for a low-cost, phaserotation-only beamforming method known as direct-sampled in-phase quadrature (DSIQ) beamforming. We show that when high-quality time-delay interpolation is used, separable DAS focusing introduces no noticeable imaging degradation under practical conditions. Similar results for DSIQ focusing are observed. In addition, a slight modification to the DSIQ focusing method greatly increases imaging contrast, making it comparable to that of DAS, despite having a wider main lobe and higher side lobes resulting from the limitations of phase-only time-delay interpolation. Compared with non-separable 2-D imaging, up to a 20-fold increase in frame rate is possible with the separable method. When implemented on a smart-phone-oriented processor to focus data from a 60 × 60 channel array using a 40 × 40 aperture, the frame rate per C-mode volume slice increases from 16 to 255 Hz for DAS, and from 11 to 193 Hz for DSIQ. Energy usage per frame is similarly reduced from 75 to 4.8 mJ/ frame for DAS, and from 107 to 6.3 mJ/frame for DSIQ. We also show that the separable method outperforms 2-D FFT-based focusing by a factor of 1.64 at these data sizes. This data indicates that with the optimal design choices, separable 2-D beamforming can

  12. Assessment of the spatial homogeneity of artery dimension parameters with high frame rate 2-D B-mode.

    PubMed

    Meinders, J M; Brands, P J; Willigers, J M; Kornet, L; Hoeks, A P

    2001-06-01

    To elicit vessel wall inhomogeneities in diameter and distension along an arterial segment, a 2-D vessel wall-tracking system based on fast B-mode has been developed. The frame rate of a 7.5-MHz linear-array transducer (length 36 mm) is enhanced by increasing the pulse-repetition frequency to 10 kHz, decreasing the number of echo lines per frame from 128 to 64, or increasing the interspacing between echo lines with a factor of two or four. Dedicated software has been developed to extract for each echo-line the end-diastolic diameter from the B-mode image and the 2-D distension waveform from the underlying radiofrequency (RF) information. The method is validated in tubes with various focal lesion sizes. Straight segments of presumably homogeneous common carotid arteries have also been tested. The temporal and spatial SD of diameter or distension reveals inhomogeneities in time or space (i.e., inhomogeneities in artery characteristics). The method can be implemented in echo systems supporting high frame rates and real-time processing of radiofrequency data. PMID:11516538

  13. A video event trigger for high frame rate, high resolution video technology

    NASA Astrophysics Data System (ADS)

    Williams, Glenn L.

    1991-12-01

    When video replaces film the digitized video data accumulates very rapidly, leading to a difficult and costly data storage problem. One solution exists for cases when the video images represent continuously repetitive 'static scenes' containing negligible activity, occasionally interrupted by short events of interest. Minutes or hours of redundant video frames can be ignored, and not stored, until activity begins. A new, highly parallel digital state machine generates a digital trigger signal at the onset of a video event. High capacity random access memory storage coupled with newly available fuzzy logic devices permits the monitoring of a video image stream for long term or short term changes caused by spatial translation, dilation, appearance, disappearance, or color change in a video object. Pretrigger and post-trigger storage techniques are then adaptable for archiving the digital stream from only the significant video images.

  14. A video event trigger for high frame rate, high resolution video technology

    NASA Technical Reports Server (NTRS)

    Williams, Glenn L.

    1991-01-01

    When video replaces film the digitized video data accumulates very rapidly, leading to a difficult and costly data storage problem. One solution exists for cases when the video images represent continuously repetitive 'static scenes' containing negligible activity, occasionally interrupted by short events of interest. Minutes or hours of redundant video frames can be ignored, and not stored, until activity begins. A new, highly parallel digital state machine generates a digital trigger signal at the onset of a video event. High capacity random access memory storage coupled with newly available fuzzy logic devices permits the monitoring of a video image stream for long term or short term changes caused by spatial translation, dilation, appearance, disappearance, or color change in a video object. Pretrigger and post-trigger storage techniques are then adaptable for archiving the digital stream from only the significant video images.

  15. Meteor wake in high frame-rate images--implications for the chemistry of ablated organic compounds

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; Stenbaek-Nielsen, Hans C.

    2004-01-01

    Extraterrestrial organic matter may have been chemically altered into forms more ameanable for prebiotic chemistry in the wake of a meteor after ablation. We measured the rate of cooling of the plasma in the meteor wake from the intensity decay just behind a meteoroid by freezing its motion in high frame-rate 1000 frames/s video images, with an intensified camera that has a short phosphor decay time. Though the resulting cooling rate was found to be lower than theoretically predicted, our calculations indicated that there would have been insufficient collisions to break apart large organic compounds before most reactive radicals and electrons were lost from the air plasma. Organic molecules delivered from space to the early Earth via meteors might therefore have survived in a chemically altered form. In addition, we discovered that relatively small meteoroids generated far-ultraviolet emission that is absorbed in the immediate environment of the meteoroid, which may chemically alter the atmosphere over a much larger region than previously recognized.

  16. Observation of Kilohertz Quasiperiodic Oscillations from the Atoll Source 4U 1702-429 by RXTE

    NASA Technical Reports Server (NTRS)

    Markwardt, C. B.; Strohmayer, Tod E.; Swank, Jean H.

    1998-01-01

    We present results of Rossi X-Ray Timing Explorer (RXTE) observations of the atoll source 4U 1702-429 in the middle of its luminosity range. Kilohertz-range quasiperiodic oscillations (QPOS) were observed first as a narrow (FWHM approximately 7 Hz) peak near 900 Hz, and later as a pair consisting of a narrow peak in the range 625 825 Hz and a faint broad (FWHM 91 Hz) peak. When the two peaks appeared simultaneously the separation was 333 +/- 5 Hz. Six type I thermonuclear bursts were detected, of which five exhibited almost coherent oscillations near 330 Hz, which makes 4U 1702-429 only the second source to show burst oscillations very close to the kilohertz QPO separation frequency. The energy spectrum and color-color diagram indicate that the source executed variations in the range between the "island" and "lower banana" atoll states. In addition to the kilohertz variability, oscillations at approximately 10, approximately 35, and 80 Hz were also detected at various times, superimposed on a red noise continuum. The centroid of the approximately 35 Hz QPO tracks the frequency of the kilohertz oscillation when they were both present. A Lense-Thirring gravitomagnetic precession interpretation appears more plausible in this case, compared to other atoll sources with low frequency QPOs.

  17. Mapping from frame-driven to frame-free event-driven vision systems by low-rate rate coding and coincidence processing--application to feedforward ConvNets.

    PubMed

    Pérez-Carrasco, José Antonio; Zhao, Bo; Serrano, Carmen; Acha, Begoña; Serrano-Gotarredona, Teresa; Chen, Shouchun; Linares-Barranco, Bernabé

    2013-11-01

    Event-driven visual sensors have attracted interest from a number of different research communities. They provide visual information in quite a different way from conventional video systems consisting of sequences of still images rendered at a given "frame rate." Event-driven vision sensors take inspiration from biology. Each pixel sends out an event (spike) when it senses something meaningful is happening, without any notion of a frame. A special type of event-driven sensor is the so-called dynamic vision sensor (DVS) where each pixel computes relative changes of light or "temporal contrast." The sensor output consists of a continuous flow of pixel events that represent the moving objects in the scene. Pixel events become available with microsecond delays with respect to "reality." These events can be processed "as they flow" by a cascade of event (convolution) processors. As a result, input and output event flows are practically coincident in time, and objects can be recognized as soon as the sensor provides enough meaningful events. In this paper, we present a methodology for mapping from a properly trained neural network in a conventional frame-driven representation to an event-driven representation. The method is illustrated by studying event-driven convolutional neural networks (ConvNet) trained to recognize rotating human silhouettes or high speed poker card symbols. The event-driven ConvNet is fed with recordings obtained from a real DVS camera. The event-driven ConvNet is simulated with a dedicated event-driven simulator and consists of a number of event-driven processing modules, the characteristics of which are obtained from individually manufactured hardware modules. PMID:24051730

  18. Development of reprogrammable high frame-rate detector devices for laser communication pointing, acquisition and tracking

    NASA Astrophysics Data System (ADS)

    Norton, Terita; Conner, Kenneth; Covington, Richard; Ngo, Hung; Rink, Christine

    2008-02-01

    A Two Terminal Laser Communication Test Bed has been developed at The Aerospace Corporation. This paper presents the design and preliminary results of a reprogrammable detector within the Test Bed for use in pointing, acquisition, and tracking between a Satellite-to-Satellite Laser Communication link. The detector may be commanded by an emulated spacecraft Command & Data Handling subsystem to switch between full-array scanning and "small sized" N x M pixel Field of View (FOV) for high-rate laser tracking. The approach follows a parallel path to implement the signal processing algorithm on two different hardware resources: a Field Programmable Gate Array (FPGA) and a Digital Signal Processor (DSP). The focus of this effort is to present a methodology for testing and evaluating various techniques for advanced focal plane array (FPA) hardware, as well as sensor FPA control, image processing and laser beam X & Y position algorithms.

  19. High frame-rate TCSPC-FLIM using a novel SPAD-based image sensor

    NASA Astrophysics Data System (ADS)

    Gersbach, M.; Trimananda, R.; Maruyama, Y.; Fishburn, M.; Stoppa, D.; Richardson, J.; Walker, R.; Henderson, R. K.; Charbon, E.

    2010-08-01

    Imaging techniques based on time-correlated single photon counting (TCSPC), such as fluorescence lifetime imaging microscopy (FLIM), rely on fast single-photon detectors as well as timing electronics in the form of time-to-digital or time-to-analog converters. Conventional systems rely on stand-alone or small arrays (up to 32) of detectors and external timing and memory modules. We recently developed a fully integrated image sensor containing 32×32 pixels and fabricated in a 130 nm CMOS technology. The chip produces an overall data rate of 10Gb/s in terms of time-of-arrival measurements in each pixel. As opposed to conventional single detector FLIM systems, the present system can acquire a full image, albeit at low resolution, without the need of an optical scanning system. As a consequence the complexity of the optical setup is reduced and the acquisition speed is dramatically increased. We show the potential of this new technology by presenting high time resolution (119 ps) TCSPC-FLIM images of pollen grains with acquisition times as low as 69 ms. Furthermore, the low noise (~100 Hz) and high photon detection probability (up to 35%) ensure a good photon economy over the visible spectrum. We believe that this technology will open the way to fast TCSPC-FLIM recordings of transient signals in the bio- and life sciences, such as in neuron signaling.

  20. Using high frame rate CMOS sensors for three-dimensional eye tracking.

    PubMed

    Clarke, A H; Ditterich, J; Drüen, K; Schönfeld, U; Steineke, C

    2002-11-01

    A novel three-dimensional eye tracker is described and its performance evaluated. In contrast to previous devices based on conventional video standards, the present eye tracker is based on programmable CMOS image sensors, interfaced directly to digital processing circuitry to permit real-time image acquisition and processing. This architecture provides a number of important advantages, including image sampling rates of up to 400/sec measurement, direct pixel addressing for preprocessing and acquisition,and hard-disk storage of relevant image data. The reconfigurable digital processing circuitry also facilitates inline optmization of the front-end, time-critical processes. The primary acquisition algorithm for tracking the pupil and other eye features is designed around the generalized Hough transform. The tracker permits comprehensive measurement of eye movement (three degrees of freedom) and head movement (six degrees of freedom), and thus provides the basis for many types of vestibulo-oculomotor and visual research. The device has been qualified by the German Space Agency (DLR) and NASA for deployment on the International Space Station. It is foreseen that the device will be used together with appropriate stimulus generators as a general purpose facility for visual and vestibular experiments. Initial verification studies with an artificial eye demonstrate a measurement resolution of better than 0.1 degrees in all three components (i.e.,system noise for each of the components measured as 0.006 degrees H, 0.005 degrees V, and 0.016 degrees T. Over a range of +/-20 degrees eye rotation, linearity was found to be <0.5% (H), <0.5% (V), and <2.0% (T). A comparison with the scleral search coil technique yielded near equivalent values for the system noise and the thickness of Listing's plane. PMID:12564559

  1. High-Frame-Rate Synthetic Aperture Ultrasound Imaging Using Mismatched Coded Excitation Waveform Engineering: A Feasibility Study.

    PubMed

    Lashkari, Bahman; Zhang, Kaicheng; Mandelis, Andreas

    2016-06-01

    Mismatched coded excitation (CE) can be employed to increase the frame rate of synthetic aperture ultrasound imaging. The high autocorrelation and low cross correlation (CC) of transmitted signals enables the identification and separation of signal sources at the receiver. Thus, the method provides B-mode imaging with simultaneous transmission from several elements and capability of spatial decoding of the transmitted signals, which makes the imaging process equivalent to consecutive transmissions. Each transmission generates its own image and the combination of all the images results in an image with a high lateral resolution. In this paper, we introduce two different methods for generating multiple mismatched CEs with an identical frequency bandwidth and code length. Therefore, the proposed families of mismatched CEs are able to generate similar resolutions and signal-to-noise ratios. The application of these methods is demonstrated experimentally. Furthermore, several techniques are suggested that can be used to reduce the CC between the mismatched codes. PMID:27101603

  2. Frame-rate analysis of arterial blood flow in human and rat using laser speckle image sensing

    NASA Astrophysics Data System (ADS)

    Yokoi, Naomichi; Sato, Junki; Shimatani, Yuichi; Kyoso, Masaki; Funamizu, Hideki; Aizu, Yoshihisa

    2014-05-01

    In imaging of blood flow by means of a laser speckle technique, we have proposed so far an estimation parameter based on the spatial contrast of speckle patterns observed for the blood flow in skin tissue and a blood vessel. This parameter enable us to image a relative blood flow distribution from a single speckle pattern, thus, it analyzes the blood flow with a frame-rate of an imaging device used. In this study, we investigated availability of this parameter for detecting changes in arterial blood flow caused by medication and cold stimulation to the skin tissue. Experiments were conducted for an anesthetized rat and a human wrist to confirm the feasibility of the present parameter.

  3. High-frame rate imaging of two-phase flow in a thin rectangular channel using fast neutrons.

    PubMed

    Zboray, R; Mor, I; Dangendorf, V; Stark, M; Tittelmeier, K; Cortesi, M; Adams, R

    2014-08-01

    We have demonstrated the feasibility of performing high-frame-rate, fast neutron radiography of air-water two-phase flows in a thin channel with rectangular cross section. The experiments have been carried out at the accelerator facility of the Physikalisch-Technische Bundesanstalt. A polychromatic, high-intensity fast neutron beam with average energy of 6 MeV was produced by 11.5 MeV deuterons hitting a thick Be target. Image sequences down to 10 ms exposure times were obtained using a fast-neutron imaging detector developed in the context of fast-neutron resonance imaging. Different two-phase flow regimes such as bubbly slug and churn flows have been examined. Two phase flow parameters like the volumetric gas fraction, bubble size and mean bubble velocities have been measured. The first results are promising, improvements for future experiments are also discussed. PMID:24709611

  4. Stand-Alone Front-End System for High-Frequency, High-Frame-Rate Coded Excitation Ultrasonic Imaging

    PubMed Central

    Park, Jinhyoung; Hu, Changhong; Shung, K. Kirk

    2012-01-01

    A stand-alone front-end system for high-frequency coded excitation imaging was implemented to achieve a wider dynamic range. The system included an arbitrary waveform amplifier, an arbitrary waveform generator, an analog receiver, a motor position interpreter, a motor controller and power supplies. The digitized arbitrary waveforms at a sampling rate of 150 MHz could be programmed and converted to an analog signal. The pulse was subsequently amplified to excite an ultrasound transducer, and the maximum output voltage level achieved was 120 Vpp. The bandwidth of the arbitrary waveform amplifier was from 1 to 70 MHz. The noise figure of the preamplifier was less than 7.7 dB and the bandwidth was 95 MHz. Phantoms and biological tissues were imaged at a frame rate as high as 68 frames per second (fps) to evaluate the performance of the system. During the measurement, 40-MHz lithium niobate (LiNbO3) single-element lightweight (<0.28 g) transducers were utilized. The wire target measurement showed that the −6-dB axial resolution of a chirp-coded excitation was 50 µm and lateral resolution was 120 µm. The echo signal-to-noise ratios were found to be 54 and 65 dB for the short burst and coded excitation, respectively. The contrast resolution in a sphere phantom study was estimated to be 24 dB for the chirp-coded excitation and 15 dB for the short burst modes. In an in vivo study, zebrafish and mouse hearts were imaged. Boundaries of the zebrafish heart in the image could be differentiated because of the low-noise operation of the implemented system. In mouse heart images, valves and chambers could be readily visualized with the coded excitation. PMID:23443698

  5. A High-Frequency High Frame Rate Duplex Ultrasound Linear Array Imaging System for Small Animal Imaging

    PubMed Central

    Zhang, Lequan; Xu, Xiaochen; Hu, Changhong; Sun, Lei; Yen, Jesse T.; Cannata, Jonathan M.; Shung, K. Kirk

    2010-01-01

    High-frequency (HF) ultrasound imaging has been shown to be useful for non-invasively imaging anatomical structures of the eye and small animals in biological and pharmaceutical research, achieving superior spatial resolution. Cardiovascular research utilizing mice requires not only real-time B-scan imaging, but also ultrasound Doppler to evaluate both anatomy and blood flow of the mouse heart. This paper reports the development of a high frequency ultrasound duplex imaging system capable of both B-mode imaging and Doppler flow measurements, using a 64-element linear array. The system included a HF pulsed-wave Doppler module, a 32-channel HF B-mode imaging module, a PC with a 200 MS/s 14-bit A/D card, and real-time LabView software. A 50dB signal-to-noise ratio (SNR) and a depth of penetration of larger than 12 mm were achieved using a 35 MHz linear array with 50 μm pitch. The two-way beam widths were determined to be 165 μm to 260 μm and the clutter energy to total energy ratio (CTR) were 9.1 dB to 12 dB, when the array was electronically focused at different focal points at depths from 4.8 mm to 9.6 mm. The system is capable of acquiring real-time B-mode images at a rate greater than 400 frames per second (fps) for a 4.8 × 13 mm field of view, using a 30 MHz 64-element linear array with 100 μm pitch. Sample in vivo cardiac high frame rate images and duplex images of mouse hearts are shown to assess its current imaging capability and performance for small animals. PMID:20639149

  6. Overlapping reading frames in closely related human papillomaviruses result in modular rates of selection within E2.

    PubMed

    Narechania, Apurva; Terai, Masanori; Burk, Robert D

    2005-05-01

    A core group of four open reading frames (ORFs) is present in all known papillomaviruses (PVs): the E1 and E2 replication/transcription proteins and the L1 and L2 structural proteins. Because they are involved in processes that are essential to PV propagation, the sequences of these proteins are well-conserved. However, sequencing of novel subtypes for human papillomaviruses (HPV) 54 (AE9) and 82 (AE2/IS39), coupled to analysis of four other closely related genital HPV pairs, indicated that E2 has a higher dN/dS ratio than E1, L1 or L2. The elevated ratio is not homogeneous across the length of the ORF, but instead varies with respect to E2's three domains. The E2 hinge region is of particular interest, because its hypervariability (dN/dS>1) differs markedly from the two domains that it joins: the transcription-activation domain and the DNA-binding domain. Deciphering whether the hinge region's high rate of non-synonymous change is the result of positive Darwinian selection or relaxed constraint depends on the evolutionary behaviour of E4, an ORF that overlaps E2. The E2 hinge region is contained within E4 and non-synonymous changes in the hinge are associated with a disproportionate amount of synonymous change in E4, a case of simultaneous positive and purifying selection in overlapping reading frames. Modular rates of selection among E2 domains are a likely consequence of the presence of an embedded E4. E4 appears to be positioned in a part of the HPV genome that can tolerate non-synonymous change and purifying selection of E4 may be indicative of its functional importance. PMID:15831941

  7. Mapping from Frame-Driven to Frame-Free Event-Driven Vision Systems by Low-Rate Rate-Coding and Coincidence Processing. Application to Feed Forward ConvNets.

    PubMed

    Perez-Carrasco, J A; Zhao, B; Serrano, C; Acha, B; Serrano-Gotarredona, T; Chen, S; Linares-Barranco, B

    2013-04-10

    Event-driven visual sensors have attracted interest from a number of different research communities. They provide visual information in quite a different way from conventional video systems consisting of sequences of still images rendered at “frame rate”. Event-driven vision sensors take inspiration from biology. A special type of Event-driven sensor is the so called Dynamic-Vision-Sensor (DVS) where each pixel computes relative changes of light, or “temporal contrast”. Pixel events become available with micro second delays with respect to “reality”. These events can be processed “as they flow” by a cascade of event (convolution) processors. As a result, input and output event flows are practically coincident, and objects can be recognized as soon as the sensor provides enough meaningful events. In this paper we present a methodology for mapping from a properly trained neural network in a conventional Frame-driven representation, to an Event-driven representation. The method is illustrated by studying Event-driven Convolutional Neural Networks (ConvNet) trained to recognize rotating human silhouettes or high speed poker card symbols. The Event-driven ConvNet is fed with recordings obtained from a real DVS camera. The Event-driven ConvNet is simulated with a dedicated Event-driven simulator, and consists of a number of Event-driven processing modules the characteristics of which are obtained from individually manufactured hardware modules. PMID:23589589

  8. The Magnetohydrodynamical Model of Kilohertz Quasi-periodic Oscillations in Neutron Star Low-mass X-Ray Binaries (II)

    NASA Astrophysics Data System (ADS)

    Shi, Chang-Sheng; Zhang, Shuang-Nan; Li, Xiang-Dong

    2014-08-01

    We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model is reexamined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636-53, 4U 1608-52, 4U 1915-15, 4U 1728-34, and XTE 1807-294) with measured spins. In this model, the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at a low accretion rate and the twin kHz QPOs encounter a top ceiling at a high accretion rate due to the restriction of the innermost stable circular orbit.

  9. The magnetohydrodynamical model of kilohertz quasi-periodic oscillations in neutron star low-mass X-ray binaries (II)

    SciTech Connect

    Shi, Chang-Sheng; Zhang, Shuang-Nan; Li, Xiang-Dong

    2014-08-10

    We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model is reexamined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636-53, 4U 1608-52, 4U 1915-15, 4U 1728-34, and XTE 1807-294) with measured spins. In this model, the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at a low accretion rate and the twin kHz QPOs encounter a top ceiling at a high accretion rate due to the restriction of the innermost stable circular orbit.

  10. Effect of scanline orientation on ventricular flow propagation: assessment using high frame-rate color Doppler echocardiography

    NASA Technical Reports Server (NTRS)

    Greenberg, N. L.; Castro, P. L.; Drinko, J.; Garcia, M. J.; Thomas, J. D.

    2000-01-01

    Color M-mode echocardiography has recently been utilized to describe diastolic flow propagation velocity (Vp) in the left ventricle. While increasing temporal resolution from 15 to 200 Hz, this M-mode technique requires the user to select a single scanline, potentially limiting quantification of Vp due to the complex three-dimensional inflow pattern. We previously performed computational fluid dynamics simulations to demonstrate the insignificance of the scanline orientation, however geometric complexity was limited. The purpose of this study was to utilize high frame-rate 2D color Doppler images to investigate the importance of scanline selection in patients for the quantification of Vp. 2D color Doppler images were digitally acquired at 50 frames/s in 6 subjects from the apical 4-chamber window (System 5, GE/Vingmed, Milwaukee, WI). Vp was determined for a set of scanlines positioned through 5 locations across the mitral annulus (from the anterior to posterior mitral annulus). An analysis of variance was performed to examine the differences in Vp as a function of scanline position. Vp was not effected by scanline position in sampled locations from the center of the mitral valve towards the posterior annulus. Although not statistically significant, there was a trend to slower propagation velocities on the anterior side of the valve (60.8 +/- 16.7 vs. 54.4 +/- 13.6 cm/s). This study clinically validates our previous numerical experiment showing that Vp is insensitive to small perturbations of the scanline through the mitral valve. However, further investigation is necessary to examine the impact of ventricular geometry in pathologies including dilated cardiomyopathy.

  11. Physical evaluation of a high-frame-rate extended dynamic range flat panel detector for real-time cone beam computed tomography applications

    NASA Astrophysics Data System (ADS)

    Boyce, Sarah J.; Chawla, Amarpreet; Samei, Ehsan

    2005-04-01

    The use of flat panel detectors in computed tomography (CT) systems can improve resolution, reduce system cost, and add operational flexibility by combining fluoroscopy and radiography applications within CT systems. However, some prior studies have suggested that flat panel detectors would not perform well in CT applications due to their lack of high dynamic range, lag artifacts, and inadequate frame rate. The purpose of this study was to perform a physical evaluation of a prototype flat panel detector capable of high frame rates and extended dynamic range. The flat panel detector used had a pixel size of 194 microns and a matrix size of 2048x1536. The detector could be configured for several combinations of frame rate and matrix size up to 750 frames per second for a 512x16 matrix size with 4x4 binning. The evaluation was performed in terms of the MTF and DQE as a function of frame rate and exposure at the IEC RQA5 (~75 kVp, 21 mm Al) beam quality. The image lag was evaluated in terms of temporal-frequency dependent transfer function. Offset shift were also evaluated. Preliminary results indicate 0.1 MTF at 0.92 cycles/mm and DQE(0) of approximately 0.8, 0.6, 0.4, and 0.22 at 0.144, 0.065, 0.035, and 0.008 mR per frame exposures. The temporal MTF exhibited a low-frequency drop and a value of 0.5 at the Nyquist frequency. Offset shift was negligible. Considering high frame rate capabilities of the new detector, the results suggest that the detector has potential for use in real-time CT applications including CT angiography.

  12. Pulse Inversion Chirp Coded Tissue Harmonic Imaging (PI-CTHI) of Zebrafish Heart Using High Frame Rate Ultrasound Biomicroscopy

    PubMed Central

    Park, Jinhyoung; Huang, Ying; Chen, Ruimin; Lee, Jungwoo; Cummins, Thomas M.; Zhou, Qifa; Lien, Ching-Ling; Shung, K. K.

    2012-01-01

    This paper reports a pulse inversion chirp coded tissue harmonic imaging (PI-CTHI) method for visualizing small animal hearts that provides fine spatial resolution at a high frame rate without sacrificing the echo signal to noise ratio (eSNR). A 40 MHz lithium niobate (LiNbO3) single element transducer is employed to evaluate the performance of PI-CTHI by scanning tungsten wire targets, spherical anechoic voids, and zebrafish hearts. The wire phantom results show that PI-CTHI improves the eSNR by 4 dB from that of conventional pulse inversion tissue harmonic imaging (PI-THI), while still maintaining a spatial resolution of 88 and 110 μm in the axial and lateral directions, respectively. The range side lobe level of PI-CTHI is 11 dB lower than that of band-pass filtered CTHI (or F-CTHI). In the anechoic sphere phantom study, the contrast-to-noise ratio of PI-CTHI is found to be 2.7, indicating a 34% enhancement over conventional PI-THI. Due to such improved eSNR and contrast resolution, blood clots in zebrafish hearts can be readily visualized throughout heart regeneration after 20% of the ventricle is removed. Disappearance of the clots in the early stages of the regeneration has been observed for 7 days without sacrificing the fish. PMID:22930467

  13. Ultra-scale vehicle tracking in low spatial-resolution and low frame-rate overhead video

    SciTech Connect

    Carrano, C J

    2009-05-20

    Overhead persistent surveillance systems are becoming more capable at acquiring wide-field image sequences for long time-spans. The need to exploit this data is becoming ever greater. The ability to track a single vehicle of interest or to track all the observable vehicles, which may number in the thousands, over large, cluttered regions while they persist in the imagery either in real-time or quickly on-demand is very desirable. With this ability we can begin to answer a number of interesting questions such as, what are normal traffic patterns in a particular region or where did that truck come from? There are many challenges associated with processing this type of data, some of which we will address in the paper. Wide-field image sequences are very large with many thousands of pixels on a side and are characterized by lower resolutions (e.g. worse than 0.5 meters/pixel) and lower frame rates (e.g. a few Hz or less). The objects in the scenery can vary in size, density, and contrast with respect to the background. At the same time the background scenery provides a number of clutter sources both man-made and natural. We describe our current implementation of an ultrascale capable multiple-vehicle tracking algorithm for overhead persistent surveillance imagery as well as discuss the tracking and timing performance of the currently implemented algorithm which is aimed at utilizing grayscale electrooptical image sequences alone for the track segment generation.

  14. Categorization of Fetal Heart Rate Decelerations in American and European Practice: Importance and Imperative of Avoiding Framing and Confirmation Biases.

    PubMed

    Sholapurkar, Shashikant L

    2015-09-01

    Interpretation of electronic fetal monitoring (EFM) remains controversial and unsatisfactory. Fetal heart rate (FHR) decelerations are the commonest aberrant feature on cardiotocographs and considered "center-stage" in the interpretation of EFM. A recent American study suggested that the lack of correlation of American three-tier system to neonatal acidemia may be due to the current peculiar nomenclature of FHR decelerations leading to loss of meaning. The pioneers like Hon and Caldeyro-Barcia classified decelerations based primarily on time relationship to contractions and not on etiology per se. This critical analysis debates pros and cons of significant anchoring/framing and confirmation biases in defining different types of decelerations based primarily on the shape (slope) or time of descent. It would be important to identify benign early decelerations correctly to avoid unnecessary intervention as well as to improve the positive predictive value of the other types of decelerations. Currently the vast majority of decelerations are classed as "variable". This review shows that the most common rapid decelerations during contractions with trough corresponding to peak of contraction cannot be explained by "cord-compression" hypothesis but by direct/pure (defined here as not mediated through baro-/chemoreceptors) or non-hypoxic vagal reflex. These decelerations are benign, most likely and mainly a result of head-compression and hence should be called "early" rather than "variable". Standardization is important but should be appropriate and withstand scientific scrutiny. Significant framing and confirmation biases are necessarily unscientific and the succeeding three-tier interpretation systems and structures embodying these biases would be dysfunctional and clinically unhelpful. Clinical/pathophysiological analysis and avoidance of flaws/biases suggest that a more physiological and scientific categorization of decelerations should be based on time relationship to

  15. Categorization of Fetal Heart Rate Decelerations in American and European Practice: Importance and Imperative of Avoiding Framing and Confirmation Biases

    PubMed Central

    Sholapurkar, Shashikant L.

    2015-01-01

    Interpretation of electronic fetal monitoring (EFM) remains controversial and unsatisfactory. Fetal heart rate (FHR) decelerations are the commonest aberrant feature on cardiotocographs and considered “center-stage” in the interpretation of EFM. A recent American study suggested that the lack of correlation of American three-tier system to neonatal acidemia may be due to the current peculiar nomenclature of FHR decelerations leading to loss of meaning. The pioneers like Hon and Caldeyro-Barcia classified decelerations based primarily on time relationship to contractions and not on etiology per se. This critical analysis debates pros and cons of significant anchoring/framing and confirmation biases in defining different types of decelerations based primarily on the shape (slope) or time of descent. It would be important to identify benign early decelerations correctly to avoid unnecessary intervention as well as to improve the positive predictive value of the other types of decelerations. Currently the vast majority of decelerations are classed as “variable”. This review shows that the most common rapid decelerations during contractions with trough corresponding to peak of contraction cannot be explained by “cord-compression” hypothesis but by direct/pure (defined here as not mediated through baro-/chemoreceptors) or non-hypoxic vagal reflex. These decelerations are benign, most likely and mainly a result of head-compression and hence should be called “early” rather than “variable”. Standardization is important but should be appropriate and withstand scientific scrutiny. Significant framing and confirmation biases are necessarily unscientific and the succeeding three-tier interpretation systems and structures embodying these biases would be dysfunctional and clinically unhelpful. Clinical/pathophysiological analysis and avoidance of flaws/biases suggest that a more physiological and scientific categorization of decelerations should be based on

  16. Frequency offset dependence of adiabatic rotating frame relaxation rate constants: relevance to MRS investigations of metabolite dynamics in vivo.

    PubMed

    Mangia, Silvia; Liimatainen, Timo; Garwood, Michael; Tkac, Ivan; Henry, Pierre-Gilles; Deelchand, Dinesh; Michaeli, Shalom

    2011-08-01

    In this work, we investigated the frequency-offset dependence of the rotating frame longitudinal (R(1ρ)) and transverse (R(2ρ)) relaxation rate constants when using hyperbolic-secant adiabatic full passage pulses or continuous-wave spin-lock irradiation. Phantom and in vivo measurements were performed to validate theoretical predictions of the dominant relaxation mechanisms existing during adiabatic full passage pulses when using different settings of the frequency offset relative to the carrier. In addition, adiabatic R(1ρ) and R(2ρ) values of total creatine and N-acetylaspartate were measured in vivo from the human brain at 4 T. When the continuous-wave pulse power was limited to safe specific absorption rates for humans, simulations revealed a strong dependence of R(1ρ) and R(2ρ) values on the frequency offset for both dipolar interactions and anisochronous exchange mechanisms. By contrast, theoretical and experimental results showed adiabatic R(1ρ) and R(2ρ) values to be practically invariant within the large subregion of the bandwidth of the hyperbolic-secant pulse where complete inversion was achieved. However, adiabatic R(1ρ) and R(2ρ) values of the methyl protons of total creatine (at 3.03 ppm) were almost doubled when compared with those of the methyl protons of N-acetylaspartate (at 2.01 ppm) in spite of the fact that these resonances were in the flat region of the inversion band of the adiabatic full passage pulses. We conclude that differences in adiabatic R(1ρ) and R(2ρ) values of human brain metabolites are not a result of their chemical shifts, but instead reflect differences in dynamics. PMID:21264976

  17. Frequency offset dependence of adiabatic rotating frame relaxation rate constants: relevance to MRS investigations of metabolite dynamics in vivo

    PubMed Central

    Mangia, Silvia; Liimatainen, Timo; Garwood, Michael; Tkac, Ivan; Henry, Pierre-Gilles; Deelchand, Dinesh; Michaeli, Shalom

    2011-01-01

    In this work, we investigated the frequency-offset dependence of the rotating frame longitudinal (R1ρ) and transverse (R2ρ) relaxation rate constants when using hyperbolic-secant adiabatic full passage pulses or continuous-wave spin-lock irradiation. Phantom and in vivo measurements were performed to validate theoretical predictions of the dominant relaxation mechanisms existing during adiabatic full passage pulses when using different settings of the frequency offset relative to the carrier. In addition, adiabatic R1ρ and R2ρ values of total creatine and N-acetylaspartate were measured in vivo from the human brain at 4 T. When the continuous-wave pulse power was limited to safe specific absorption rates for humans, simulations revealed a strong dependence of R1ρ and R2ρ values on the frequency offset for both dipolar interactions and anisochronous exchange mechanisms. By contrast, theoretical and experimental results showed adiabatic R1ρ and R2ρ values to be practically invariant within the large subregion of the bandwidth of the hyperbolic-secant pulse where complete inversion was achieved. However, adiabatic R1ρ and R2ρ values of the methyl protons of total creatine (at 3.03 ppm) were almost doubled when compared with those of the methyl protons of N-acetylaspartate (at 2.01 ppm) in spite of the fact that these resonances were in the flat region of the inversion band of the adiabatic full passage pulses. We conclude that differences in adiabatic R1ρ and R2ρ values of human brain metabolites are not a result of their chemical shifts, but instead reflect differences in dynamics. PMID:21264976

  18. Efficient Photometry In-Frame Calibration (EPIC) Gaussian Corrections for Automated Background Normalization of Rate-Tracked Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Griesbach, J.; Wetterer, C.; Sydney, P.; Gerber, J.

    Photometric processing of non-resolved Electro-Optical (EO) images has commonly required the use of dark and flat calibration frames that are obtained to correct for charge coupled device (CCD) dark (thermal) noise and CCD quantum efficiency/optical path vignetting effects respectively. It is necessary to account/calibrate for these effects so that the brightness of objects of interest (e.g. stars or resident space objects (RSOs)) may be measured in a consistent manner across the CCD field of view. Detected objects typically require further calibration using aperture photometry to compensate for sky background (shot noise). For this, annuluses are measured around each detected object whose contained pixels are used to estimate an average background level that is subtracted from the detected pixel measurements. In a new photometric calibration software tool developed for AFRL/RD, called Efficient Photometry In-Frame Calibration (EPIC), an automated background normalization technique is proposed that eliminates the requirement to capture dark and flat calibration images. The proposed technique simultaneously corrects for dark noise, shot noise, and CCD quantum efficiency/optical path vignetting effects. With this, a constant detection threshold may be applied for constant false alarm rate (CFAR) object detection without the need for aperture photometry corrections. The detected pixels may be simply summed (without further correction) for an accurate instrumental magnitude estimate. The noise distribution associated with each pixel is assumed to be sampled from a Poisson distribution. Since Poisson distributed data closely resembles Gaussian data for parameterized means greater than 10, the data may be corrected by applying bias subtraction and standard-deviation division. EPIC performs automated background normalization on rate-tracked satellite images using the following technique. A deck of approximately 50-100 images is combined by performing an independent median

  19. Applying high frame-rate digital radiography and dual-energy distributed-sources for advanced tomosynthesis

    NASA Astrophysics Data System (ADS)

    Travish, Gil; Rangel, Felix J.; Evans, Mark A.; Schmiedehausen, Kristin

    2013-09-01

    Conventional radiography uses a single point x-ray source with a fan or cone beam to visualize various areas of the human body. An imager records the transmitted photons—historically film and now increasingly digital radiography (DR) flat panel detectors—followed by optional image post-processing. Some post-processing techniques of particular interest are tomosynthesis, and dual energy subtraction. Tomosynthesis adds the ability to recreate quasi-3D images from a series of 2D projections. These exposures are typically taken along an arc or other path; and, tomosynthesis reconstruction is used to form a three-dimensional representation of the area of interest. Dual-energy radiography adds the ability to enhance or "eliminate" structures based on their different attenuation of well-separated end-point energies in two exposures. These advanced capabilities come at a high cost in terms of complexity, imaging time, capital equipment, space, and potentially reduced image quality due to motion blur if acquired sequentially. Recently, the prospect of creating x-ray sources, which are composed of arrays of micro-emitters, has been put forward. These arrays offer a flat-panel geometry and may afford advantages in fabrication methodology, size and cost. They also facilitate the use of the dual energy technology. Here we examine the possibility of using such an array of x-ray sources combined with high frame-rate (~kHz) DR detectors to produce advanced medical images without the need for moving gantries or other complex motion systems. Combining the advantages of dual energy imaging with the ability to determine the relative depth location of anatomical structures or pathological findings from imaging procedures should prove to be a powerful diagnostic tool. We also present use cases that would benefit from the capabilities of this modality.

  20. Low-noise, fast frame-rate InGaAs 320 x 256 FPA for hyperspectral applications

    NASA Astrophysics Data System (ADS)

    Vermeiren, Jan; Van Bogget, Urbain; Van Horebeek, Guido; Bentell, Jonas; Verbeke, Peet; Colin, Thierry

    2009-05-01

    InGaAs is the material of preference for uncooled imaging in the [0.9-1.7 μm] SWIR range, as it can be manufactured on low cost InP substrates in a mainstream technology for optical telecommunications. By removing the substrate the spectral range can be extended to the [0.6 - 1.7 μm] range. In this way low cost, room temperature operated FPAs cameras for imaging and hyperspectral applications can be developed. The FPA is built around a low power CTIA stage with 3 S&H capacitors in the 20*20 um2 unit cell. This approach results in a synchronous shutter operation, which will support both ITR and IWR operation. In IWR mode the integration dead time is limited to max. 10 μsec. The CDS operation yields in a high sensitivity combined with a low noise: This presentation will focus on the development of a 20 μm pitch 320*256 device, with the following main characteristics: 20 μV/e-sensitivity and < 60 e-noise. The 4 low-power, differential outputs are enabling to drive an output load of > 30 pF at 40 Msamples/sec each, resulting in a > 1700 Hz frame rate, while at the same time the overall nominal power dissipation is < 200 mW. The ROIC is realized in a 0.35 um technology and the outputs are designed to drive directly a 3.3 V, 1.5 V VCM differential AD convertor. The circuit also supports a NDR operating mode to further reduce the noise of the FPA. A small from factor camera with Cameralink output is built around this FPA.

  1. Kilohertz-Resolution Spectroscopy of Cold Atoms with an Optical Frequency Comb

    SciTech Connect

    Fortier, T. M.; Le Coq, Y.; Stalnaker, J. E.; Diddams, S. A.; Oates, C. W.; Hollberg, L.; Ortega, D.

    2006-10-20

    We have performed sub-Doppler spectroscopy on the narrow intercombination line of cold calcium atoms using the amplified output of a femtosecond laser frequency comb. Injection locking of a 657-nm diode laser with a femtosecond comb allows for two regimes of amplification, one in which many lines of the comb are amplified, and one where a single line is predominantly amplified. The output of the laser in both regimes was used to perform kilohertz-level spectroscopy. This experiment demonstrates the potential for high-resolution absolute-frequency spectroscopy over the entire spectrum of the frequency comb output using a single high-finesse optical reference cavity.

  2. Kilohertz-resolution spectroscopy of cold atoms with an optical frequency comb.

    PubMed

    Fortier, T M; Coq, Y Le; Stalnaker, J E; Ortega, D; Diddams, S A; Oates, C W; Hollberg, L

    2006-10-20

    We have performed sub-Doppler spectroscopy on the narrow intercombination line of cold calcium atoms using the amplified output of a femtosecond laser frequency comb. Injection locking of a 657-nm diode laser with a femtosecond comb allows for two regimes of amplification, one in which many lines of the comb are amplified, and one where a single line is predominantly amplified. The output of the laser in both regimes was used to perform kilohertz-level spectroscopy. This experiment demonstrates the potential for high-resolution absolute-frequency spectroscopy over the entire spectrum of the frequency comb output using a single high-finesse optical reference cavity. PMID:17155398

  3. Description of a 20 kilohertz power distribution system

    NASA Technical Reports Server (NTRS)

    Hansen, I. G.

    1986-01-01

    A single phase, 440 VRMS, 20 kHz power distribution system with a regulated sinusoidal wave form is discussed. A single phase power system minimizes the wiring, sensing, and control complexities required in a multi-sourced redundantly distributed power system. The single phase addresses only the distribution links multiphase lower frequency inputs and outputs accommodation techniques are described. While the 440 V operating potential was initially selected for aircraft operating below 50,000 ft, this potential also appears suitable for space power systems. This voltage choice recognizes a reasonable upper limit for semiconductor ratings, yet will direct synthesis of 220 V, 3 power. A 20 kHz operating frequency was selected to be above the range of audibility, minimize the weight of reactive components, yet allow the construction of single power stages of 25 to 30 kW. The regulated sinusoidal distribution system has several advantages. With a regulated voltage, most ac/dc conversions involve rather simple transformer rectifier applications. A sinusoidal distribution system, when used in conjunction with zero crossing switching, represents a minimal source of EMI. The present state of 20 kHz power technology includes computer controls of voltage and/or frequency, low inductance cable, current limiting circuit protection, bi-directional power flow, and motor/generator operating using standard induction machines. A status update and description of each of these items and their significance is presented.

  4. Description of a 20 Kilohertz power distribution system

    NASA Technical Reports Server (NTRS)

    Hansen, I. G.

    1986-01-01

    A single phase, 440 VRMS, 20 kHz power distribution system with a regulated sinusoidal wave form is discussed. A single phase power system minimizes the wiring, sensing, and control complexities required in a multi-sourced redundantly distributed power system. The single phase addresses only the distribution link; mulitphase lower frequency inputs and outputs accommodation techniques are described. While the 440 V operating potential was initially selected for aircraft operating below 50,000 ft, this potential also appears suitable for space power systems. This voltage choice recognizes a reasonable upper limit for semiconductor ratings, yet will direct synthesis of 220 V, 3 power. A 20 kHz operating frequency was selected to be above the range of audibility, minimize the weight of reactive components, yet allow the construction of single power stages of 25 to 30 kW. The regulated sinusoidal distribution system has several advantages. With a regulated voltage, most ac/dc conversions involve rather simple transformer rectifier applications. A sinusoidal distribution system, when used in conjunction with zero crossing switching, represents a minimal source of EMI. The present state of 20 kHz power technology includes computer controls of voltage and/or frequency, low inductance cable, current limiting circuit protection, bi-directional power flow, and motor/generator operating using standard induction machines. A status update and description of each of these items and their significance is presented.

  5. A kilohertz approach to Strombolian-style eruptions

    NASA Astrophysics Data System (ADS)

    Taddeucci, Jacopo; Scarlato, Piergiorgio; Del Bello, Elisabetta; Gaudin, Damien

    2015-04-01

    Accessible volcanoes characterized by persistent, relatively mild Strombolian-style explosive activity have historically hosted multidisciplinary studies of eruptions. These studies, focused on geophysical signals preceding, accompanying, and following the eruptions, have provided key insights on the physical processes driving the eruptions. However, the dynamic development of the single explosions that characterize this style of activity remained somewhat elusive, due to the timescales involved (order of 0.001 seconds). Recent technological advances now allow recording and synchronizing different data sources on time scales relevant to the short timescales involved in the explosions. In the last several years we developed and implemented a field setup that integrates visual and thermal imaging with acoustic and seismic recordings, all synchronized and acquired at timescales of 100-10000 Hz. This setup has been developed at several active volcanoes. On the one hand, the combination of these different techniques provides unique information on the dynamics and energetics of the explosions, including the parameterization of individual ejection pulses within the explosions, the ejection and emplacement of pyroclasts and their coupling-decoupling with the gas phases, the different stages of development of the eruption jets, and their reflection in the associated acoustic and seismic signals. On the other hand, the gained information provides foundation for better understanding and interpreting the signals acquired, at lower sampling rates but routinely, from volcano monitoring networks. Perhaps even more important, our approach allows parameterizing differences and commonalities in the explosions from different volcanoes and settings.

  6. High-frame-rate low-latency hardware-in-the-loop image generation: an illustration of the particle method and DIME

    NASA Astrophysics Data System (ADS)

    Cantle, Allan J.; Devlin, Malachy; Lord, Eric; Chamberlain, Richard

    2000-07-01

    New computing architectures based on the DIME standard have been previously introduced which allow for processing of high frame rate imaging systems which may also need low latency capability, a common requirement for HWIL systems. This paper is presented in two sections: To achieve future realism in image generation systems for hardware-in-the-loop (HWIL) testing a significant increase in processing power is required, but additionally a suitable architecture is essential to provide low latency response on the data flow. Nallatech previously introduced DIME as a novel platform for HWIL systems which is capable of handling sub-frame latencies and greater than 100 Hz frame rates. We will demonstrate the system operating on traditional complex imaging problems, such as large convolution masks of 13 X 13 and also on new image generation techniques such as the particle method which is being developed by Matra British Aerospace Dynamics UK (MBDUK). MBDUK are proceeding on upgrading existing HWIL image generation systems for real-time particle models, to higher frame rates and increased complexity. Using Nallatech's latest DIME based architectures, models containing thousands of individual particles can be created at frame rates over 100 Hz and a resolution of 1024 X 1024 oversampled 4 times. This is possible because particle models exhibit high levels of parallelism ideal for exploiting the architecture of an FPGA. This paper will demonstrate the versatility of these particle models to create highly realistic signatures in terms of spatial dynamics and IR signature. Particle models are ideal for simulating dynamic objects such as flares, exhaust plumes, fires and explosions.

  7. Nanoscale Mapping of Dielectric Properties of Nanomaterials from Kilohertz to Megahertz Using Ultrasmall Cantilevers.

    PubMed

    Cadena, Maria J; Sung, Seung Hyun; Boudouris, Bryan W; Reifenberger, Ronald; Raman, Arvind

    2016-04-26

    Electrostatic force microscopy (EFM) is often used for nanoscale dielectric spectroscopy, the measurement of local dielectric properties of materials as a function of frequency. However, the frequency range of atomic force microscopy (AFM)-based dielectric spectroscopy has been limited to a few kilohertz by the resonance frequency and noise of soft microcantilevers used for this purpose. Here, we boost the frequency range of local dielectric spectroscopy by 3 orders of magnitude from a few kilohertz to a few megahertz by developing a technique that exploits the high resonance frequency and low thermal noise of ultrasmall cantilevers (USCs). We map the frequency response of the real and imaginary components of the capacitance gradient (∂C(ω)/∂z) by using second-harmonic EFM and a theoretical model, which relates cantilever dynamics to the complex dielectric constant. We demonstrate the method by mapping the nanoscale dielectric spectrum of polymer-based materials for organic electronic devices. Beyond offering a powerful extension to AFM-based dielectric spectroscopy, the approach also allows the identification of electrostatic excitation frequencies which affords high dielectric contrast on nanomaterials. PMID:26972782

  8. Detection of a 1258-Hz high-amplitude kilohertz quasi-periodic oscillation in the ultracompact X-ray binary 1A 1246-588

    NASA Astrophysics Data System (ADS)

    Jonker, P. G.; in't Zand, J. J. M.; Méndez, M.; van der Klis, M.

    2007-07-01

    We have observed the ultracompact low-mass X-ray binary (LMXB) 1A 1246-588 with the Rossi X-ray Timing Explorer (RXTE). In this paper we report the discovery of a kilohertz quasi-periodic oscillation (QPO) in 1A 1246-588. The kilohertz QPO was only detected when the source was in a soft high-flux state reminiscent of the lower banana branch in atoll sources. Only one kilohertz QPO peak is detected at a relatively high frequency of 1258 +/- 2 Hz and at a single trial significance of more than 7σ. Kilohertz QPOs with a higher frequency have only been found on two occasions in 4U 0614+09. Furthermore, the frequency is higher than that found for the lower kilohertz QPO in any source, strongly suggesting that the QPO is the upper of the kilohertz QPO pair often found in LMXBs. The full width at half-maximum is 25 +/- 4 Hz, making the coherence the highest found for an upper kilohertz QPO. From a distance estimate of ~6 kpc from a radius expansion burst we derive that 1A 1246-588 is at a persistent flux of ~0.2-0.3 per cent of the Eddington flux, hence 1A 1246-588 is one of the weakest LMXBs for which a kilohertz QPO has been detected. The rms amplitude in the 5-60 keV band is 27 +/- 3 per cent; this is the highest for any kilohertz QPO source so far, in line with the general anticorrelation between source luminosity and rms amplitude of the kilohertz QPO peak identified before. Using the X-ray spectral information we produce a colour-colour diagram. The source behaviour in this diagram provides further evidence for the atoll nature of the source.

  9. Quantum frames

    NASA Astrophysics Data System (ADS)

    Brown, Matthew J.

    2014-02-01

    The framework of quantum frames can help unravel some of the interpretive difficulties i the foundation of quantum mechanics. In this paper, I begin by tracing the origins of this concept in Bohr's discussion of quantum theory and his theory of complementarity. Engaging with various interpreters and followers of Bohr, I argue that the correct account of quantum frames must be extended beyond literal space-time reference frames to frames defined by relations between a quantum system and the exosystem or external physical frame, of which measurement contexts are a particularly important example. This approach provides superior solutions to key EPR-type measurement and locality paradoxes.

  10. A Medium-Format, Mixed-Mode Pixel Array Detector for Kilohertz X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Tate, M. W.; Chamberlain, D.; Green, K. S.; Philipp, H. T.; Purohit, P.; Strohman, C.; Gruner, S. M.

    2013-03-01

    An x-ray pixel array detector (PAD) capable of framing up to 1 kHz is described. This hybrid detector is constructed from a 3-side buttable, 128×128 pixel module based upon the mixed-mode pixel array detector (MMPAD) chip developed jointly by Cornell and Area Detector Systems Corporation (Poway, CA). The chip uses a charge integrating front end for a high instantaneous count rate yet with single photon sensitivity. In-pixel circuitry utilizing a digital overflow counter extends the per frame dynamic range to >4×107 x-rays/pixel. Results are shown from a base configuration of a 2×3 module array (256×384 pixels).

  11. Comparison and experimental validation of two potential resonant viscosity sensors in the kilohertz range

    NASA Astrophysics Data System (ADS)

    Lemaire, Etienne; Heinisch, Martin; Caillard, Benjamin; Jakoby, Bernhard; Dufour, Isabelle

    2013-08-01

    Oscillating microstructures are well established and find application in many fields. These include force sensors, e.g. AFM micro-cantilevers or accelerometers based on resonant suspended plates. This contribution presents two vibrating mechanical structures acting as force sensors in liquid media in order to measure hydrodynamic interactions. Rectangular cross section microcantilevers as well as circular cross section wires are investigated. Each structure features specific benefits, which are discussed in detail. Furthermore, their mechanical parameters and their deflection in liquids are characterized. Finally, an inverse analytical model is applied to calculate the complex viscosity near the resonant frequency for both types of structures. With this approach it is possible to determine rheological parameters in the kilohertz range in situ within a few seconds. The monitoring of the complex viscosity of yogurt during the fermentation process is used as a proof of concept to qualify at least one of the two sensors in opaque mixtures.

  12. Recursive adaptive frame integration limited

    NASA Astrophysics Data System (ADS)

    Rafailov, Michael K.

    2006-05-01

    Recursive Frame Integration Limited was proposed as a way to improve frame integration performance and mitigate issues related to high data rate needed for conventional frame integration. The technique applies two thresholds - one tuned for optimum probability of detection, the other to manage required false alarm rate - and allows a non-linear integration process that, along with Signal-to-Noise Ratio (SNR) gain, provides system designers more capability where cost, weight, or power considerations limit system data rate, processing, or memory capability. However, Recursive Frame Integration Limited may have performance issues when single frame SNR is really low. Recursive Adaptive Frame Integration Limited is proposed as a means to improve limited integration performance with really low single frame SNR. It combines the benefits of nonlinear recursive limited frame integration and adaptive thresholds with a kind of conventional frame integration.

  13. Multi-kilohertz Microlaser Altimeter(MMLA)Real-time Scan Footprint Mapping Software

    NASA Astrophysics Data System (ADS)

    Sanovia, J.

    2003-12-01

    It is expected that this near Real-time Scan Footprint Mapping Software (R-T Scan) display will alert us to any missed areas that we can re-fly to obtain more complete coverage. The value-added custom software is the Visual Basic Data conversion package. This software captures the GPS NEMA string(s) from the 2nd serial port, reads the attitude data form (the shared file of "most recent" attitude data), and performs a geometric projection of 10 (user adjustable) hypothetical laser scan angles to ground based latitude and longitude coordinates. The Lat/Long data are then converted back into the NEMA string format used by Street Atlas. The Multi-kilohertz Micro Laser Altimeter (MMLA) acquires high spatial resolution digital topographic databases and can observe geographical terrains such as hydrological runoff, measure ice sheet thickness, and the changes in lakes and reservoirs. The MMLA is ideal for making topographical (digital) maps of forest settings and cities. (NASA/GSFC 920.3) In order to maximize flight time efficiency and to avoid the potential disastrous situation of missing a target of prime importance, we have developed the MMLA R-T Scan.

  14. Kilohertz organic complementary inverters driven by surface-grafting conducting polypyrrole electrodes

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Zhang, Suna; Li, Liqiang; Chen, Xiaosong; Xu, Zeyang; Wu, Kunjie; Li, Hongwei; Meng, Yancheng; Wang, Wenchong; Hu, Wenping; Chi, Lifeng

    2016-09-01

    Surface-grafting conducting polymer has advantage to circumvent the difficulty in patterning as well as the weak interface adhesion on substrate of the conventional conducting polymer, which would be desirable for its application as electrodes in electronic devices. In this work, the patterned surface-grafting polypyrrole (PPY) is used as electrode, which shows merits such as strong interface adhesion, robustness against solvent treatment, easy scaling-up, and good conductivity. Remarkably, the surface-grafting PPY electrodes can efficiently drive both p-type and n-type organic field-effect transistors. By combining p-/n-type transistors, organic complementary inverters are constructed with PPY electrodes, which exhibit low operational voltage (<8 V), high gain (6-17), and low power dissipation (several tens of nW). The switching voltage is approximately 0.5Vdd with a high noise margin (>70% of 0.5Vdd). Dynamic switching measurements indicate that the inverter has an operational frequency of about 3.3 kHz. This is the first report on kilohertz organic complementary inverter driven with surface-grafting conducting polymer electrodes. High device performance, together with the facile patternability and other merits, may promote the application of surface-grafting conducting polymer electrode in the field of organic electronics.

  15. A low-power and small-area column-level ADC for high frame-rate CMOS pixel sensor

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Morel, F.; Hu-Guo, C.; Hu, Y.

    2014-07-01

    CMOS pixel sensors (CPS) have demonstrated performances meeting the specifications of the International Linear Collider (ILC) vertex detector (VTX). This paper presents a low-power and small-area 4-bit column-level analog-to-digital converter (ADC) for CMOS pixel sensors. The ADC employs a self-timed trigger and completes the conversion by performing a multi-bit/step approximation. As in the outer layers of the ILC vertex detector hit density is of the order of a few per thousand, in order to reduce power consumption, the ADC is designed to work in two modes: active mode and idle mode. The ADC is fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. It is implemented with 48 columns in a sensor prototype. Each column ADC covers an area of 35 ×545 μm2. The measured temporal noise and Fixed Pattern Noise (FPN) are 0.96 mV and 0.40 mV, respectively. The power consumption, for a 3 V supply and 6.25 MS/s sampling rate, is 486 μW during idle time, which is by far the most frequently employed one. This value rises to 714 μW in the case of the active mode. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.49/-0.28 LSB and 0.29/-0.20 LSB, respectively.

  16. Differential fiber-specific block of nerve conduction in mammalian peripheral nerves using kilohertz electrical stimulation

    PubMed Central

    Patel, Yogi A.

    2015-01-01

    Kilohertz electrical stimulation (KES) has been shown to induce repeatable and reversible nerve conduction block in animal models. In this study, we characterized the ability of KES stimuli to selectively block specific components of stimulated nerve activity using in vivo preparations of the rat sciatic and vagus nerves. KES stimuli in the frequency range of 5–70 kHz and amplitudes of 0.1–3.0 mA were applied. Compound action potentials were evoked using either electrical or sensory stimulation, and block of components was assessed through direct nerve recordings and muscle force measurements. Distinct observable components of the compound action potential had unique conduction block thresholds as a function of frequency of KES. The fast component, which includes motor activity, had a monotonically increasing block threshold as a function of the KES frequency. The slow component, which includes sensory activity, showed a nonmonotonic block threshold relationship with increasing KES frequency. The distinct trends with frequency of the two components enabled selective block of one component with an appropriate choice of frequency and amplitude. These trends in threshold of the two components were similar when studying electrical stimulation and responses of the sciatic nerve, electrical stimulation and responses of the vagus nerve, and sensorimotor stimulation and responses of the sciatic nerve. This differential blocking effect of KES on specific fibers can extend the applications of KES conduction block to selective block and stimulation of neural signals for neuromodulation as well as selective control of neural circuits underlying sensorimotor function. PMID:25878155

  17. High frame rate and high line density ultrasound imaging for local pulse wave velocity estimation using motion matching: A feasibility study on vessel phantoms.

    PubMed

    Li, Fubing; He, Qiong; Huang, Chengwu; Liu, Ke; Shao, Jinhua; Luo, Jianwen

    2016-04-01

    Pulse wave imaging (PWI) is an ultrasound-based method to visualize the propagation of pulse wave and to quantitatively estimate regional pulse wave velocity (PWV) of the arteries within the imaging field of view (FOV). To guarantee the reliability of PWV measurement, high frame rate imaging is required, which can be achieved by reducing the line density of ultrasound imaging or transmitting plane wave at the expense of spatial resolution and/or signal-to-noise ratio (SNR). In this study, a composite, full-view imaging method using motion matching was proposed with both high temporal and spatial resolution. Ultrasound radiofrequency (RF) data of 4 sub-sectors, each with 34 beams, including a common beam, were acquired successively to achieve a frame rate of ∼507 Hz at an imaging depth of 35 mm. The acceleration profiles of the vessel wall estimated from the common beam were used to reconstruct the full-view (38-mm width, 128-beam) image sequence. The feasibility of mapping local PWV variation along the artery using PWI technique was preliminarily validated on both homogeneous and inhomogeneous polyvinyl alcohol (PVA) cryogel vessel phantoms. Regional PWVs for the three homogeneous phantoms measured by the proposed method were in accordance with the sparse imaging method (38-mm width, 32-beam) and plane wave imaging method. Local PWV was estimated using the above-mentioned three methods on 3 inhomogeneous phantoms, and good agreement was obtained in both the softer (1.91±0.24 m/s, 1.97±0.27 m/s and 1.78±0.28 m/s) and the stiffer region (4.17±0.46 m/s, 3.99±0.53 m/s and 4.27±0.49 m/s) of the phantoms. In addition to the improved spatial resolution, higher precision of local PWV estimation in low SNR circumstances was also obtained by the proposed method as compared with the sparse imaging method. The proposed method might be helpful in disease detections through mapping the local PWV of the vascular wall. PMID:26773791

  18. Optical coherence elastography based on high speed imaging of single-hot laser-induced acoustic waves at 16 kHz frame rate

    NASA Astrophysics Data System (ADS)

    Song, Shaozhen; Hsieh, Bao-Yu; Wei, Wei; Shen, Tueng; Pelivanov, Ivan; O'Donnell, Matthew; Wang, Ruikang K.

    2016-03-01

    Shear wave OCE (SW-OCE) is a novel technique that relies on the detection of the localized shear wave speed to map tissue elasticity. In this study, we demonstrate high speed imaging to capture single-shot transient shear wave propagation for SW-OCE. The fast imaging speed is achieved using a Fourier domain mode-locked (FDML) high-speed swept-source OCT (SS-OCT) system. The frame rate of shear wave imaging is 16 kHz, at an A-line rate of ~1.62 MHz, enabling the detection of high-frequency shear waves up to 8 kHz in bandwidth. Several measures are taken to improve the phase-stability of the SS-OCT system, and the measured displacement sensitivity is ~10 nanometers. To facilitate non-contact elastography, shear waves are generated with the photo-thermal effect using an ultra-violet pulsed laser. High frequency shear waves launched by the pulsed laser contain shorter wavelengths and carry rich localized elasticity information. Benefiting from single-shot acquisition, each SWI scan only takes 2.5 milliseconds, and the reconstruction of the elastogram can be performed in real-time with ~20 Hz refresh rate. SW-OCE measurements are demonstrated on porcine cornea ex vivo. This study is the first demonstration of an all-optical method to perform real-time 3D SW-OCE. It is hoped that this technique will be applicable in the clinic to obtain high-resolution localized quantitative measurements of tissue biomechanical properties.

  19. In vivo imaging flow cytometry based on laser scanning two-photon microscopy at kHz cross-sectional frame rate

    NASA Astrophysics Data System (ADS)

    Kong, Lingjie; Tang, Jianyong; Cui, Meng

    2016-03-01

    In vivo flow cytometry has found numerous applications in biology and pharmacology. However, conventional cytometry does not provide the detailed morphological information that is needed to fully determine the phenotype of individual circulating cells. Imaging cytometry, capable of visualizing the morphology and dynamics of the circulating cells at high spatiotemporal resolution, is highly desired. Current wide-field based image cytometers are limited in the imaging depth and provide only two-dimensional resolution. For deep tissue imaging, laser scanning two-photon fluorescence microscopy (TPM) is widely adopted. However, for applications in flow cytometry, the axial scanning speed of current TPMs is inadequate to provide high-speed cross-sectional imaging of vasculature. We have integrated an optical phase-locked ultrasound lens into a standard TPM and achieved microsecond-scale axial scanning. With a galvo scanner for transverse scanning, we achieved kHz cross-sectional frame rate. Here we report its applications for in vivo deformability cytometry and in vivo imaging flow cytometry, and demonstrate the capability of imaging dynamical morphologies of flowing cells, distinguishing cells and cellular clusters, and simultaneously quantifying different cell populations based on their fluorescent labels.

  20. Reference Frames and Relativity.

    ERIC Educational Resources Information Center

    Swartz, Clifford

    1989-01-01

    Stresses the importance of a reference frame in mechanics. Shows the Galilean transformation in terms of relativity theory. Discusses accelerated reference frames and noninertial reference frames. Provides examples of reference frames with diagrams. (YP)

  1. Digital 640x512 / 15μm InSb detector for high frame rate, high sensitivity, and low power applications

    NASA Astrophysics Data System (ADS)

    Markovitz, T.; Pivnik, I.; Calahorra, Z.; Ilan, E.; Hirsh, I.; Zeierman, E.; Eylon, M.; Kahanov, E.; Kogan, I.; Fishler, N.; Brumer, M.; Lukomsky, I.

    2011-06-01

    Pelican-D is a new digital 640x512 / 15μm InSb detector developed by SCD to serve a number of applications. The Readout Integrated Circuit (ROIC) has a digital output which can be calibrated to a signal resolution in the 13-15 bit range. Besides the digital output, the detector has some additional advantages over other MWIR detectors of the same format. The high frequency of data output, which supports a full image frame rate of over 300Hz, is very useful in systems that track fast evolving events such as Missile Warning Systems (MWS), Missile Seekers and some Thermographic applications. Another important characteristic of the detector is related to an operation mode with relatively low readout noise. This mode of operation is especially beneficial in applications where the background radiation is low such as in long range surveillance systems. For imaging systems where very high sensitivity is required, the ROIC can be coupled to an epi-InSb detector array and have a dark current at 77K that is lower by a factor of 15 with respect to standard InSb. Alternatively, Pelican-D with epi-InSb can be operated at 95K with a standard dark current and sensitivity. Such an elevated operating temperature enables the use of cryogenic coolers of relatively low size, weight and power for applications such as Hand-held cameras, miniature gimbaled systems, and light UAVs. In this work we present in detail the characteristic performance of the new detector and its applications.

  2. Noncontact phase-sensitive dynamic optical coherence elastography at megahertz rate

    NASA Astrophysics Data System (ADS)

    Singh, Manmohan; Wu, Chen; Liu, Chih-Hao; Li, Jiasong; Schill, Alexander; Nair, Achuth; Kistenev, Yury V.; Larin, Kirill V.

    2016-03-01

    Dynamic optical coherence elastography (OCE) techniques have shown great promise at quantitatively obtaining the biomechanical properties of tissue. However, the majority of these techniques have required multiple temporal OCT acquisitions (M-B mode) and corresponding excitations, which lead to clinically unfeasible acquisition times and potential tissue damage. Furthermore, the large data sets and extended laser exposures hinder their translation to the clinic, where patient discomfort and safety are critical criteria. In this work we demonstrate noncontact true kilohertz frame-rate dynamic optical coherence elastography by directly imaging a focused air-pulse induced elastic wave with a home-built phase-sensitive OCE system based on a 4X buffered Fourier Domain Mode Locked swept source laser with an A-scan rate of ~1.5 MHz. The elastic wave was imaged at a frame rate of ~7.3 kHz using only a single excitation. In contrast to previous techniques, successive B-scans were acquired over the measurement region (B-M mode) in this work. The feasibility of this method was validated by quantifying the elasticity of tissue-mimicking agar phantoms as well as porcine corneas ex vivo at different intraocular pressures. The results demonstrate that this method can acquire a depth-resolved elastogram in milliseconds. The reduced data set enabled a rapid elasticity assessment, and the ultra-fast acquisition speed allowed for a clinically safe laser exposure to the cornea.

  3. Target activated frame capture

    NASA Astrophysics Data System (ADS)

    Roberts, G. Marlon; Fitzgerald, James; McCormack, Michael; Steadman, Robert

    2008-04-01

    Over the past decade, technological advances have enabled the use of increasingly intelligent systems for battlefield surveillance. These systems are triggered by a combination of external devices including acoustic and seismic sensors. Such products are mainly used to detect vehicles and personnel. These systems often use infra-red imagery to record environmental information, but Textron Defense Systems' Terrain Commander is one of a small number of systems which analyze these images for the presence of targets. The Terrain Commander combines acoustic, infrared, magnetic, seismic, and visible spectrum sensors to detect nearby targets in military scenarios. When targets are detected by these sensors, the cameras are triggered and images are captured in the infrared and visible spectrum. In this paper we discuss a method through which such systems can perform target tracking in order to record and transmit only the most pertinent surveillance images. This saves bandwidth which is crucial because these systems often use communication systems with throughputs below 2400bps. This method is expected to be executable on low-power processors at frame rates exceeding 10HZ. We accomplish this by applying target activated frame capture algorithms to infra-red video data. The target activated frame capture algorithms combine edge detection and motion detection to determine the best frames to be transmitted to the end user. This keeps power consumption and bandwidth requirements low. Finally, the results of the algorithm are analyzed.

  4. PanDAR: a wide-area, frame-rate, and full color lidar with foveated region using backfilling interpolation upsampling

    NASA Astrophysics Data System (ADS)

    Mundhenk, T. Nathan; Kim, Kyungnam; Owechko, Yuri

    2015-01-01

    LIDAR devices for on-vehicle use need a wide field of view and good fidelity. For instance, a LIDAR for avoidance of landing collisions by a helicopter needs to see a wide field of view and show reasonable details of the area. The same is true for an online LIDAR scanning device placed on an automobile. In this paper, we describe a LIDAR system with full color and enhanced resolution that has an effective vertical scanning range of 60 degrees with a central 20 degree fovea. The extended range with fovea is achieved by using two standard Velodyne 32-HDL LIDARs placed head to head and counter rotating. The HDL LIDARS each scan 40 degrees vertical and a full 360 degrees horizontal with an outdoor effective range of 100 meters. By positioning them head to head, they overlap by 20 degrees. This creates a double density fovea. The LIDAR returns from the two Velodyne sensors do not natively contain color. In order to add color, a Point Grey LadyBug panoramic camera is used to gather color data of the scene. In the first stage of our system, the two LIDAR point clouds and the LadyBug video are fused in real time at a frame rate of 10 Hz. A second stage is used to intelligently interpolate the point cloud and increase its resolution by approximately four times while maintaining accuracy with respect to the 3D scene. By using GPGPU programming, we can compute this at 10 Hz. Our backfilling interpolation methods works by first computing local linear approximations from the perspective of the LIDAR depth map. The color features from the image are used to select point cloud support points that are the best points in a local group for building the local linear approximations. This makes the colored point cloud more detailed while maintaining fidelity to the 3D scene. Our system also makes objects appearing in the PanDAR display easier to recognize for a human operator.

  5. Thirty Frames per Second

    ERIC Educational Resources Information Center

    Kelly, Bruce

    2006-01-01

    Analyzing real motion with frame-by-frame precision can be conducted using modestly priced digital-video camcorders. Although well below the 1,000 frames-per-second threshold of high-speed cameras, commercially available camcorders grab 30 frames per second. A replay dissected at this lower frequency is fun to watch, challenges students'…

  6. Classroom Discourse Frames.

    ERIC Educational Resources Information Center

    Pennington, Martha C.

    An analysis of classroom discourse proposes four frames, modeled as concentric circles. The inner most circle is the lesson frame, removed or sheltered from outside influences and most likely, in a language class, to maintain second-language usage. The next frame from the center is the lesson-support frame, an intermediate layer of classroom…

  7. A multi-frame, megahertz CCd imager

    SciTech Connect

    Mendez, Jacob; Balzer, Stephen; Watson, Scott; Reich, Robert

    2010-01-01

    To record high-speed, explosively driven, events, a high efficiency, high speed, imager has been fabricated which is capable of framing rates of 2 MHz. This device utilizes a 512 x 512 pixel charge coupled device (CCD) with a 25cm{sup 2} active area, and incorporates an electronic shutter technology designed for back-illuminated CCD's, making this the largest and fastest back-illuminated CCD in the world. Characterizing an imager capable of this frame rate presents unique challenges. High speed LED drivers and intense radioactive sources are needed to perform the most basic measurements. We investigate properties normally associated with single-frame CCD's such as read noise, full-well capacity, sensitivity, signal to noise ratio, linearity and dynamic range. In addition, we investigate several properties associated with the imager's multi-frame operation such as transient frame response and frame-to-frame isolation while contrasting our measurement techniques and results with more conventional devices.

  8. A multi-frame, megahertz CCD imager

    SciTech Connect

    Mendez, Jacob A; Balzer, Stephen J; Watson, Scott A

    2008-01-01

    A high-efficiency, high-speed imager has been fabricated capable of framing rates of 2 MHz. This device utilizes a 512 x 512 pixel charge coupled device (CCD) with a 25cmZ active area, and incorporates an electronic shutter technology designed for back-illuminated CCD's, making this the largest and fastest back-illuminated CCD in the world. Characterizing an imager capable of this frame rate presents unique challenges. High speed LED drivers and intense radioactive sources are needed to perform basic measurements. We investigate properties normally associated with single-frame CCD's such as read noise, gain, full-well capacity, detective quantum efficiency (DQE), sensitivity, and linearity. In addition, we investigate several properties associated with the imager's multi-frame operation such as transient frame response and frame-to-frame isolation while contrasting our measurement techniques and results with more conventional devices.

  9. B-Field Determination from Magnetoacoustic Oscillations in Kilohertz Quasi-periodic Oscillation Neutron Star Binaries: Theory and Observations

    NASA Astrophysics Data System (ADS)

    Titarchuk, L. G.; Bradshaw, C. F.; Wood, K. S.

    2001-10-01

    We present a method for determining the B-field around neutron stars based on observed kilohertz and viscous quasi-periodic oscillation (QPO) frequencies used in combination with the best-fit optical depth and temperature of a Comptonization model. In the framework of the transition layer QPO model, we analyze the magnetoacoustic wave (MAW) formation in the layer between a neutron star surface and the inner edge of a Keplerian disk. We derive formulas for the MAW frequencies for different regimes of radial transition layer oscillations. We demonstrate that our model can use the QPO as a new kind of probe to determine the magnetic field strengths for 4U 1728-42, GX 340+0, and Scorpius X-1 in the zone where the QPOs occur. Observations indicate that the dependence of the viscous frequency on the Keplerian frequency is closely related to the inferred dependence of the MAW frequency on the Keplerian frequency for a dipole magnetic field. The MAW dependence is based on a single parameter, the magnetic moment of the star as estimated from the field strength in the transition layer. The best-fit magnetic moment parameter is about (0.5-1)×1025 G cm3 for all studied sources. From observational data, the magnetic fields within distances less than 20 km from the neutron star for all three sources are strongly constrained to be dipole fields with the strengths of 107-108 G on the neutron star surface.

  10. Kilohertz high power extracavity KGW yellow raman lasers based on pulse LD side-pumped ceramic Nd: YAG

    NASA Astrophysics Data System (ADS)

    Bai, Y.; Chen, X. M.; Guo, J. X.; Zhang, H. L.; Bai, J. T.; Ren, Z. Y.

    2012-03-01

    We report an efficient operation of a kilohertz nanosecond extracavity KGd(WO4)2 (KGW) crystal Raman yellow laser, which is pumped by a 532 nm lasers based on pulse laser diode (LD) side-pumped ceramic Nd: YAG, BBO electro-optical Q-switched and LBO crystal extracavity frequency doubling. With the 5 W, 10 ns and 1 kHz output power pumped at 532 nm, we obtained 2.58 W, 7.4 ns, 1 kHz second Stokes Raman laser output at 579.54 nm for 768 cm-1 Raman shift of KGW crystal, corresponding to a conversion efficiency of 51.4%. By changing the KGW crystal orientation, we further obtained 3.18 W, 7.8 ns, 1 kHz Raman pulses at 588.33 nm for 901 cm-1 Raman shift, corresponding to a conversion efficiency of 63.3%. The beam quality factors M2 of 579.54 and 588.33 nm were ( M {/x-579.54 2} = 5.829, M {/y-579.54 2} = 6.336) and ( M {/x-588.33 2} = 6.405, M {/y-588.33 2} = 6.895), respectively.

  11. Automating Frame Analysis

    SciTech Connect

    Sanfilippo, Antonio P.; Franklin, Lyndsey; Tratz, Stephen C.; Danielson, Gary R.; Mileson, Nicholas D.; Riensche, Roderick M.; McGrath, Liam

    2008-04-01

    Frame Analysis has come to play an increasingly stronger role in the study of social movements in Sociology and Political Science. While significant steps have been made in providing a theory of frames and framing, a systematic characterization of the frame concept is still largely lacking and there are no rec-ognized criteria and methods that can be used to identify and marshal frame evi-dence reliably and in a time and cost effective manner. Consequently, current Frame Analysis work is still too reliant on manual annotation and subjective inter-pretation. The goal of this paper is to present an approach to the representation, acquisition and analysis of frame evidence which leverages Content Analysis, In-formation Extraction and Semantic Search methods to provide a systematic treat-ment of a Frame Analysis and automate frame annotation.

  12. FRACTIONAL AMPLITUDE OF KILOHERTZ QUASI-PERIODIC OSCILLATION FROM 4U 1728-34: EVIDENCE OF DECLINE AT HIGHER ENERGIES

    SciTech Connect

    Mukherjee, Arunava; Bhattacharyya, Sudip E-mail: sudip@tifr.res.in

    2012-09-01

    A kilohertz quasi-periodic oscillation (kHz QPO) is an observationally robust high-frequency timing feature detected from neutron star low-mass X-ray binaries (LMXBs). This feature can be very useful to probe the superdense core matter of neutron stars and the strong gravity regime. Although many models exist in the literature, the physical origin of kHz QPO is not known, and hence this feature cannot be used as a tool yet. The energy dependence of kHz QPO fractional rms amplitude is an important piece of the jigsaw puzzle to understand the physical origin of this timing feature. It is known that the fractional rms amplitude increases with energy at lower energies. At higher energies, the amplitude is usually believed to saturate, although this is not established. We combine tens of lower kHz QPOs from a neutron star LMXB 4U 1728-34 in order to improve the signal-to-noise ratio. Consequently, we, for the first time to the best of our knowledge, find a significant and systematic decrease of the fractional rms amplitude with energy at higher photon energies. Assuming an energy spectrum model, blackbody+powerlaw, we explore if the sinusoidal variation of a single spectral parameter can reproduce the above-mentioned fractional rms amplitude behavior. Our analysis suggests that the oscillation of any single blackbody parameter is favored over the oscillation of any single power-law parameter, in order to explain the measured amplitude behavior. We also find that the quality factor of a lower kHz QPO does not plausibly depend on photon energy.

  13. VIRTUAL FRAME BUFFER INTERFACE

    NASA Technical Reports Server (NTRS)

    Wolfe, T. L.

    1994-01-01

    Large image processing systems use multiple frame buffers with differing architectures and vendor supplied user interfaces. This variety of architectures and interfaces creates software development, maintenance, and portability problems for application programs. The Virtual Frame Buffer Interface program makes all frame buffers appear as a generic frame buffer with a specified set of characteristics, allowing programmers to write code which will run unmodified on all supported hardware. The Virtual Frame Buffer Interface converts generic commands to actual device commands. The virtual frame buffer consists of a definition of capabilities and FORTRAN subroutines that are called by application programs. The virtual frame buffer routines may be treated as subroutines, logical functions, or integer functions by the application program. Routines are included that allocate and manage hardware resources such as frame buffers, monitors, video switches, trackballs, tablets and joysticks; access image memory planes; and perform alphanumeric font or text generation. The subroutines for the various "real" frame buffers are in separate VAX/VMS shared libraries allowing modification, correction or enhancement of the virtual interface without affecting application programs. The Virtual Frame Buffer Interface program was developed in FORTRAN 77 for a DEC VAX 11/780 or a DEC VAX 11/750 under VMS 4.X. It supports ADAGE IK3000, DEANZA IP8500, Low Resolution RAMTEK 9460, and High Resolution RAMTEK 9460 Frame Buffers. It has a central memory requirement of approximately 150K. This program was developed in 1985.

  14. Discovery of Kilohertz Quasi-periodic Oscillations in the Z Source GX 340+0

    NASA Astrophysics Data System (ADS)

    Jonker, Peter G.; Wijnands, Rudy; van der Klis, Michiel; Psaltis, Dimitrios; Kuulkers, Erik; Lamb, Frederick K.

    1998-06-01

    We have discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the Z source GX 340+0 with the Rossi X-Ray Timing Explorer. The X-ray hardness-intensity and color-color diagrams each show a full Z track, with an extra limb branching off the flaring branch of the Z. Both peaks moved to higher frequencies when the mass accretion rate increased. The two peaks moved from 247+/-6 and 567+/-39 Hz at the left end of the horizontal branch to 625+/-18 and 820+/-19 Hz at its right end. The higher frequency peak's rms amplitude (5-60 keV) and FWHM decreased from ~5% and 383+/-135 Hz to ~2% and 145+/-62 Hz, respectively. The rms amplitude and FWHM of the lower peak were consistent with being constant near 2.5% and 100 Hz. The kHz QPO separation was consistent with being constant at 325+/-10 Hz. Simultaneous with the kHz QPOs, we detected the horizontal-branch oscillation (HBO) and its second harmonic, at frequencies between 20 and 50 Hz, and 38 and 69 Hz, respectively. The normal-branch oscillations were only detected on the upper and middle normal branch and became undetectable on the lower normal branch. The HBO frequencies do not fall within the range predicted for Lense-Thirring precession, unless either the ratio of the neutron star moment of inertia to neutron star mass is at least 4, 1045g cm2 M-1solar, the frequencies of the HBOs are in fact the second harmonic oscillations, or the observed kHz peak difference is half the spin frequency and not the spin frequency. During a 1.2 day gap between two observations, the Z track in the hardness-intensity diagram moved to higher count rates by about 3.5%. Comparing data before and after this shift, we find that the HBO properties are determined by position on the Z track and not directly by count rate or X-ray colors.

  15. High-energy multi-kilohertz Ho-doped regenerative amplifiers around 2 µm.

    PubMed

    von Grafenstein, Lorenz; Bock, Martin; Griebner, Uwe; Elsaesser, Thomas

    2015-06-01

    We report a high-gain, cw-pumped regenerative amplifier which is based on Ho-doped crystals and seeded by a versatile broadband source emitting between 2050 and 2100 nm. The regenerative amplifier is implemented in a chirped-pulse amplification system operating at room temperature. Using Ho:YLF as gain medium, 1.1 mJ pulses with a 50 ps pulse duration and a 10 kHz repetition rate are generated at 2050 and 2060 nm, corresponding to an average power of 11 W. Using the same seed source, a 10 kHz Ho:YAG regenerative amplifier at 2090 nm is studied in the same configuration. In all cases the regenerative amplifier parameters are chosen to operate in a tunable single-energy regime without instabilities. PMID:26072833

  16. Pinch-plasma radiation source for extreme-ultraviolet lithography with a kilohertz repetition frequency.

    PubMed

    Bergmann, K; Rosier, O; Neff, W; Lebert, R

    2000-08-01

    An extreme-ultraviolet radiation source based on a xenon pinch plasma is discussed with respect to the demands on a radiation source for extreme-ultraviolet lithography. Operation of the discharge in a self-igniting-plasma mode and omitting a switch permits a very effective and low-inductive coupling of the electrically stored energy to the electrode system. The xenon plasma exhibits broadband emission characteristics that offer radiation near 11 and 13 nm. Both wavelengths are useful in combination with beryllium- and silicon-based multilayer mirrors. The plasma emits approximately 74 mW/sr at 11.5 nm and 40 mW/sr at 13.5 nm in a bandwidth of 2% when operated at a repetition frequency of 120 Hz. The source size is less than 500 microm in diameter (FWHM) when viewed from the axial direction. The pulse-to-pulse stability is better than 3.6%. First results with a repetition rate of as much as 6 kHz promise the possibility of scaling to the required emission power for extreme-ultraviolet lithography. PMID:18349959

  17. KiloHertz Radio Burst by GW conversion in Galactic Fields

    NASA Astrophysics Data System (ADS)

    Fargion, Daniele

    2016-07-01

    The very recent Gravitational Wave detection at several hundreds Hertz by LIGO due to a few tens solar masses binary black hole collapse at 400 Mpc distance imply a much abundant population of a few solar masses BH systems, bounded in a very similar but more rapid collapse event. Their number rate might be much higher than heavier tens Solar masses BH events, but their signal might be below the present LIGO detection threshold. Therefore their few or tens kiloHerts GW might be detected rarely by LIGO only when occurring in a much nearby and smaller (30 Mpc) Universe. However their graviton conversion along their flight by solar and galactic magnetic fields into radio waves may lead to tens KHz sudden radio burst. These radio bangs, foreseen more than tweny years ago, might be observed today at best from r screened radio array antenna on the Moon. If such radio array might be sent at solar system edges (Voyager distances) then the plasma dilution will allow detection even of the KHz radio waves, comparable to the recent rare LIGO frequency.

  18. Dynamics of the Frame in Visual Composition.

    ERIC Educational Resources Information Center

    Herbener, Gerald F.; And Others

    1979-01-01

    Forty-four college students rated six framed, black-and-white single object pictures to determine if the framing of an object or the field surrounding it gives it more meaning. Based on factor analysis of the results, recommendations are made for future research. (JEG)

  19. Frame independent cosmological perturbations

    SciTech Connect

    Prokopec, Tomislav; Weenink, Jan E-mail: j.g.weenink@uu.nl

    2013-09-01

    We compute the third order gauge invariant action for scalar-graviton interactions in the Jordan frame. We demonstrate that the gauge invariant action for scalar and tensor perturbations on one physical hypersurface only differs from that on another physical hypersurface via terms proportional to the equation of motion and boundary terms, such that the evolution of non-Gaussianity may be called unique. Moreover, we demonstrate that the gauge invariant curvature perturbation and graviton on uniform field hypersurfaces in the Jordan frame are equal to their counterparts in the Einstein frame. These frame independent perturbations are therefore particularly useful in relating results in different frames at the perturbative level. On the other hand, the field perturbation and graviton on uniform curvature hypersurfaces in the Jordan and Einstein frame are non-linearly related, as are their corresponding actions and n-point functions.

  20. Recursive frame integration of limited data: RAFAIL

    NASA Astrophysics Data System (ADS)

    Rafailov, Michael K.; Soli, Robert A.

    2005-08-01

    Real time infrared imaging and tracking usually requires a high probability of target detection along with a low false alarm rate, achievable only with a high "Signal-to-Noise Ratio" (SNR). Frame integration--summing of non-correlated frames--is commonly used to improve the SNR. But conventional frame integration requires significant processing to store full frames and integrate intermediate results, normalize frame data, etc. It may drive acquisition of highly specialized hardware, faster processors, dedicated frame integration circuit cards and extra memory cards. Non-stationary noise, low frequency noise correlation, non-ergodic noise, scene dynamics, or pointing accuracy may also limit performance. Recursive frame integration of limited data--RAFAIL, is proposed as a means to improve frame integration performance and mitigate the issues. The technique applies two thresholds--one tuned for optimum probability of detection, the other to manage required false alarm rate--and allows a non-linear integration process that, along with optimal noise management, provides system designers more capability where cost, weight, or power considerations limit system data rate, processing, or memory capability.

  1. Modern Steel Framed Schools.

    ERIC Educational Resources Information Center

    American Inst. of Steel Construction, Inc., New York, NY.

    In view of the cost of structural framing for school buildings, ten steel-framed schools are examined to review the economical advantages of steel for school construction. These schools do not resemble each other in size, shape, arrangement or unit cost; some are original in concept and architecture, and others are conservative. Cost and…

  2. Dragging of inertial frames.

    PubMed

    Ciufolini, Ignazio

    2007-09-01

    The origin of inertia has intrigued scientists and philosophers for centuries. Inertial frames of reference permeate our daily life. The inertial and centrifugal forces, such as the pull and push that we feel when our vehicle accelerates, brakes and turns, arise because of changes in velocity relative to uniformly moving inertial frames. A classical interpretation ascribed these forces to acceleration relative to some absolute frame independent of the cosmological matter, whereas an opposite view related them to acceleration relative to all the masses and 'fixed stars' in the Universe. An echo and partial realization of the latter idea can be found in Einstein's general theory of relativity, which predicts that a spinning mass will 'drag' inertial frames along with it. Here I review the recent measurements of frame dragging using satellites orbiting Earth. PMID:17805287

  3. Quantitative rotating frame relaxometry methods in MRI.

    PubMed

    Gilani, Irtiza Ali; Sepponen, Raimo

    2016-06-01

    Macromolecular degeneration and biochemical changes in tissue can be quantified using rotating frame relaxometry in MRI. It has been shown in several studies that the rotating frame longitudinal relaxation rate constant (R1ρ ) and the rotating frame transverse relaxation rate constant (R2ρ ) are sensitive biomarkers of phenomena at the cellular level. In this comprehensive review, existing MRI methods for probing the biophysical mechanisms that affect the rotating frame relaxation rates of the tissue (i.e. R1ρ and R2ρ ) are presented. Long acquisition times and high radiofrequency (RF) energy deposition into tissue during the process of spin-locking in rotating frame relaxometry are the major barriers to the establishment of these relaxation contrasts at high magnetic fields. Therefore, clinical applications of R1ρ and R2ρ MRI using on- or off-resonance RF excitation methods remain challenging. Accordingly, this review describes the theoretical and experimental approaches to the design of hard RF pulse cluster- and adiabatic RF pulse-based excitation schemes for accurate and precise measurements of R1ρ and R2ρ . The merits and drawbacks of different MRI acquisition strategies for quantitative relaxation rate measurement in the rotating frame regime are reviewed. In addition, this review summarizes current clinical applications of rotating frame MRI sequences. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27100142

  4. Complex equiangular tight frames

    NASA Astrophysics Data System (ADS)

    Tropp, Joel A.

    2005-08-01

    A complex equiangular tight frame (ETF) is a tight frame consisting of N unit vectors in Cd whose absolute inner products are identical. One may view complex ETFs as a natural geometric generalization of an orthonormal basis. Numerical evidence suggests that these objects do not arise for most pairs (d, N). The goal of this paper is to develop conditions on (d, N) under which complex ETFs can exist. In particular, this work concentrates on the class of harmonic ETFs, in which the components of the frame vectors are roots of unity. In this case, it is possible to leverage field theory to obtain stringent restrictions on the possible values for (d, N).

  5. Celestial Reference Frame

    NASA Astrophysics Data System (ADS)

    Jacobs, Christopher S.

    2013-09-01

    Concepts and Background: This paper gives an overview of modern celestial reference frames as realized at radio frequencies using the Very Long baseline Interferometry (VLBI) technique. We discuss basic celestial reference frame concepts, desired properties, and uses. We review the networks of antennas used for this work. We briefly discuss the history of the science of astrometry touching upon the discovery of precession, proper motion, nutation, and parallax, and the field of radio astronomy. Building Celestial Frames: Next, we discuss the multi-step process of building a celestial frame: First candidate sources are identified based on point-like properties from single dish radio telescopes surveys. Second, positions are refined using connected element interferometers such as the Very Large Array, and the ATCA. Third, positions of approximately milli-arcsecond (mas) accuracy are determined using intercontinental VLBI surveys. Fourth, sub-mas positions are determined by multiyear programs using intercontinental VLBI. These sub-mas sets of positions are then verified by multiple teams in preparation for release to non-specialists in the form of an official IAU International Celestial Reference Frame (ICRF). The process described above has until recently been largely restricted to work at S/X-band (2.3/8.4 GHz). However, in the last decade sub-mas work has expanded to include celestial frames at K-band (24 GHz), Ka-band (32 GHz), and Q-band (43 GHz). While these frames currently have the disadvantage of far smaller data sets, the astrophysical quality of the sources themselves improves at these higher frequencies and thus make these frequencies attractive for realizations of celestial reference frames. Accordingly, we review progress at these higher frequency bands. Path to the Future: We discuss prospects for celestial reference frames over the next decade. We present an example of an error budget for astrometric VLBI and discuss the budget's use as a tool for

  6. Behavior of infilled frames

    SciTech Connect

    Flanagan, R.D.; Tenbus, M.A.; Bennett, R.M.; Jamal, B.D.

    1992-09-21

    A review of current analytical methods for infilled frame behavior is conducted. A subset of these methods are applied to experimental results. Parametric studies are used to find the sensitivity of the behavior to various parameters. In-plane loading, out-of-plane inertial loading, out-of-plane interstory drift loading, and combined loadings are examined. Particular reference is made to clay tile infilled frames, and the behavior of clay tile in compression.

  7. Studying Frequency Relationships of Kilohertz Quasi-periodic Oscillations for 4U 1636-53 and Sco X-1: Observations Confront Theories

    NASA Astrophysics Data System (ADS)

    Lin, Yong-Feng; Boutelier, Martin; Barret, Didier; Zhang, Shuang-Nan

    2011-01-01

    By fitting the frequencies of simultaneous lower and upper kilohertz quasi-periodic oscillations (kHz QPOs) in two prototype neutron star (NS) QPO sources (4U 1636-53 and Sco X-1), we test the predictive power of all currently proposed QPO models. Models predict a linear, power law, or other relationship between the two frequencies. We found that for plausible NS parameters (mass and angular momentum), no model can satisfactorily reproduce the data, leading to very large chi-square values in our fittings. For both 4U 1636-53 and Sco X-1, this is largely due to the fact that the data significantly differ from a linear relationship. Some models perform relatively better but still have their own problems. Such a detailed comparison of data from models enables identification of routes for improving those models further.

  8. STUDYING FREQUENCY RELATIONSHIPS OF KILOHERTZ QUASI-PERIODIC OSCILLATIONS FOR 4U 1636-53 AND Sco X-1: OBSERVATIONS CONFRONT THEORIES

    SciTech Connect

    Lin Yongfeng; Boutelier, Martin; Barret, Didier; Zhang Shuangnan

    2011-01-10

    By fitting the frequencies of simultaneous lower and upper kilohertz quasi-periodic oscillations (kHz QPOs) in two prototype neutron star (NS) QPO sources (4U 1636-53 and Sco X-1), we test the predictive power of all currently proposed QPO models. Models predict a linear, power law, or other relationship between the two frequencies. We found that for plausible NS parameters (mass and angular momentum), no model can satisfactorily reproduce the data, leading to very large chi-square values in our fittings. For both 4U 1636-53 and Sco X-1, this is largely due to the fact that the data significantly differ from a linear relationship. Some models perform relatively better but still have their own problems. Such a detailed comparison of data from models enables identification of routes for improving those models further.

  9. The Effects of Framing Grades on Student Learning and Preferences

    ERIC Educational Resources Information Center

    Bies-Hernandez, Nicole J.

    2012-01-01

    Two experiments examined whether framing effects, in terms of losses and gains, can be extended to student learning and grading preferences. In Experiment 1, participants rated psychology course syllabi to investigate preferences for differently framed grading systems: a loss versus gain grading system. The results showed a clear framing effect…

  10. A neuroimaging investigation of attribute framing and individual differences

    PubMed Central

    Murch, Kevin B.

    2014-01-01

    Functional magnetic resonance imaging was used to evaluate the neural basis of framing effects. We tested the reflexive and reflective systems model of social cognition as it relates to framing. We also examined the relationships among frame susceptibility, intelligence and personality measures. Participants evaluated whether personal attributes applied to themselves from multiple perspectives and in positive and negative frames. Participants rated whether each statement was descriptive or not and endorsed positive frames more than negative frames. Individual differences on frame decisions enabled us to form high and low frame susceptibility groups. Endorsement of frame-consistent attributes was associated with personality factors, cognitive reflection and intelligence. Reflexive brain regions were associated with positive frames while reflective areas were associated with negative frames. Region of Interest analyses showed that frame-inconsistent responses were associated with increased activation within reflective cognitive control regions including the left dorsolateral prefrontal cortex (PFC), dorsomedial PFC and left ventrolateral PFC. Frame-consistent responses were associated with increased activation in the right orbitofrontal cortex. These results demonstrate that individual differences in frame susceptibility influence personal attribute evaluations. Overall, this study clarifies the neural correlates of the reflective and reflexive systems of social cognition as applied to decisions about social attributions. PMID:23988759

  11. Popcorn Story Frames.

    ERIC Educational Resources Information Center

    DiLella, Carol Ann

    This paper presents "popcorn story frames"--holistic outlines that facilitate comprehension when reading and writing stories, useful for outlining stories read and for creating outlines for original student stories--that are particularly useful for elementary and intermediate school students. "Popcorn" pops in a horizontal manner rather than in a…

  12. Aluminum space frame technology

    SciTech Connect

    Birch, S.

    1994-01-01

    This article examines the increased application of aluminum to the construction of automobile frames. The topics of the article include a joint venture between Audi and Alcoa, forms in which aluminum is used, new alloys and construction methods, meeting rigidity and safety levels, manufacturing techniques, the use of extrusions, die casting, joining techniques, and pollution control during manufacturing.

  13. Framing Evolution Discussion Intellectually

    ERIC Educational Resources Information Center

    Oliveira, Alandeom W.; Cook, Kristin; Buck, Gayle A.

    2011-01-01

    This study examines how a first-year biology teacher facilitates a series of whole-class discussions about evolution during the implementation of a problem-based unit. A communicative theoretical perspective is adopted wherein evolution discussions are viewed as social events that the teacher can frame intellectually (i.e., present or organize as…

  14. Framing for Scientific Argumentation

    ERIC Educational Resources Information Center

    Berland, Leema K.; Hammer, David

    2012-01-01

    In recent years, research on students' scientific argumentation has progressed to a recognition of nascent resources: Students can and do argue when they experience the need and possibility of persuading others who may hold competing views. Our purpose in this article is to contribute to this progress by applying the perspective of framing to the…

  15. Frame dragging and superenergy

    SciTech Connect

    Herrera, L.; Di Prisco, A.; Carot, J.

    2007-08-15

    We show that the vorticity appearing in stationary vacuum spacetimes is always related to the existence of a flow of superenergy on the plane orthogonal to the vorticity vector. This result, together with the previously established link between vorticity and superenergy in radiative (Bondi-Sachs) spacetimes, strengthens further the case for this latter quantity as the cause of frame dragging.

  16. Solid-state framing camera with multiple time frames

    SciTech Connect

    Baker, K. L.; Stewart, R. E.; Steele, P. T.; Vernon, S. P.; Hsing, W. W.; Remington, B. A.

    2013-10-07

    A high speed solid-state framing camera has been developed which can operate over a wide range of photon energies. This camera measures the two-dimensional spatial profile of the flux incident on a cadmium selenide semiconductor at multiple times. This multi-frame camera has been tested at 3.1 eV and 4.5 keV. The framing camera currently records two frames with a temporal separation between the frames of 5 ps but this separation can be varied between hundreds of femtoseconds up to nanoseconds and the number of frames can be increased by angularly multiplexing the probe beam onto the cadmium selenide semiconductor.

  17. Effectiveness of cigarette warning labels: examining the impact of graphics, message framing, and temporal framing.

    PubMed

    Nan, Xiaoli; Zhao, Xiaoquan; Yang, Bo; Iles, Irina

    2015-01-01

    This study examines the effectiveness of cigarette warning labels, with a specific focus on the impact of graphics, message framing (gain vs. loss), and temporal framing (present-oriented vs. future-oriented) among nonsmokers in the United States. A controlled experiment (N = 253) revealed that graphic warning labels were perceived as more effective, stronger in argument strength, and were generally liked more compared to text-only labels. In addition, loss-framed labels, compared to their gain-framed counterparts, were rated higher in perceived effectiveness, argument strength, and liking. No significant difference was observed between the present- and future-oriented frames on any of the dependent variables. Implications of the findings for antismoking communication efforts are discussed. PMID:24628288

  18. Nanosecond frame cameras

    SciTech Connect

    Frank, A M; Wilkins, P R

    2001-01-05

    The advent of CCD cameras and computerized data recording has spurred the development of several new cameras and techniques for recording nanosecond images. We have made a side by side comparison of three nanosecond frame cameras, examining them for both performance and operational characteristics. The cameras include; Micro-Channel Plate/CCD, Image Diode/CCD and Image Diode/Film; combinations of gating/data recording. The advantages and disadvantages of each device will be discussed.

  19. Frame for a firearm

    DOEpatents

    Crandall, David L.; Watson, Richard W.

    2008-03-04

    A firearm frame which is adapted to be disposed in operative relationship as a component part of a firearm, the firearm having disposed in operative relationships each with one or more of the others, a barrel, a receiver, and at least one firing mechanism; wherein the barrel and receiver form operative parts of a movable assembly and the at least one firing mechanism is disposed in a substantially stationary operative relationship therewith; the firearm frame including at least one elongated support structure discrete from the barrel and receiver, the elongated support structure being adapted to directly support the movable assembly in an operative movable relationship therewith; whereby at least one of the barrel and receiver is in direct contact with and movable on the elongated support structure; and, a firing mechanism support structure connected to the at least one elongated support structure, the firing mechanism support structure being adapted to have the firing mechanism connected thereto; the firearm frame also directly supporting the movable assembly and the firing mechanism in corresponding movable and stationary operative relationships each with the other.

  20. Electrically insulating and sealing frame

    DOEpatents

    Guthrie, Robin J.

    1983-11-08

    A combination gas seal and electrical insulator having a closed frame shape interconnects a fuel cell stack and a reactant gas plenum of a fuel cell generator. The frame can be of rectangular shape including at least one slidable spline connection in each side to permit expansion or contraction consistent with that of the walls of the gas plenum and fuel cell stack. The slidable spline connections in the frame sides minimizes lateral movement between the frame side members and sealing material interposed between the frame and the fuel cell stack or between the frame and the reactant gas plenum.

  1. Framing the ultimatum game: gender differences and autonomic responses.

    PubMed

    Sarlo, Michela; Lotto, Lorella; Palomba, Daniela; Scozzari, Simona; Rumiati, Rino

    2013-01-01

    The present study aimed at investigating whether the way offers are framed in the Ultimatum Game (UG) affects behavioral and autonomic responses in men and women. The "I give you" and "I take" expressions were used as gain and loss frames, respectively. Skin conductance and heart rate were recorded as indices of autonomic activation in response to unfair, mid-value, and fair offers. Acceptance rates were higher in men than in women under the gain frame. Moreover, men showed higher acceptance rates under the gain than under the loss frame with mid-value offers, whereas women's choices were not affected by frame. On the physiological level, men produced differential autonomic response patterns during decision-making when offers were presented under gain and loss framing. The "I take" frame, by acting as a loss frame, elicited in men the characteristic defensive response pattern that is evoked by aversive stimulation, in which increases in skin conductance are coupled with increases in heart rate. On the other hand, the "I give you" frame, by acting as a gain frame, elicited in men increases in skin conductance associated with prevailing heart rate deceleratory responses, reflecting a state of enhanced attention and orienting. In contrast, women's autonomic reactivity was not affected by frame, consistent with behavioral results. Phasic changes in heart rate were crucial in revealing differential functional significance of skin conductance responses under different frames in men, thus questioning the assumption that this autonomic measure can be used as an index of negative emotional arousal in the UG. PMID:22494303

  2. Conformal frame dependence of inflation

    NASA Astrophysics Data System (ADS)

    Domènech, Guillem; Sasaki, Misao

    2015-04-01

    Physical equivalence between different conformal frames in scalar-tensor theory of gravity is a known fact. However, assuming that matter minimally couples to the metric of a particular frame, which we call the matter Jordan frame, the matter point of view of the universe may vary from frame to frame. Thus, there is a clear distinction between gravitational sector (curvature and scalar field) and matter sector. In this paper, focusing on a simple power-law inflation model in the Einstein frame, two examples are considered; a super-inflationary and a bouncing universe Jordan frames. Then we consider a spectator curvaton minimally coupled to a Jordan frame, and compute its contribution to the curvature perturbation power spectrum. In these specific examples, we find a blue tilt at short scales for the super-inflationary case, and a blue tilt at large scales for the bouncing case.

  3. VIOLENT FRAMES IN ACTION

    SciTech Connect

    Sanfilippo, Antonio P.; McGrath, Liam R.; Whitney, Paul D.

    2011-11-17

    We present a computational approach to radical rhetoric that leverages the co-expression of rhetoric and action features in discourse to identify violent intent. The approach combines text mining and machine learning techniques with insights from Frame Analysis and theories that explain the emergence of violence in terms of moral disengagement, the violation of sacred values and social isolation in order to build computational models that identify messages from terrorist sources and estimate their proximity to an attack. We discuss a specific application of this approach to a body of documents from and about radical and terrorist groups in the Middle East and present the results achieved.

  4. The Levels of Visual Framing

    ERIC Educational Resources Information Center

    Rodriguez, Lulu; Dimitrova, Daniela V.

    2011-01-01

    While framing research has centered mostly on the evaluations of media texts, visual news discourse has remained relatively unexamined. This study surveys the visual framing techniques and methods employed in previous studies and proposes a four-tiered model of identifying and analyzing visual frames: (1) visuals as denotative systems, (2) visuals…

  5. Cognitive framing in action.

    PubMed

    Huhn, John M; Potts, Cory Adam; Rosenbaum, David A

    2016-06-01

    Cognitive framing effects have been widely reported in higher-level decision-making and have been ascribed to rules of thumb for quick thinking. No such demonstrations have been reported for physical action, as far as we know, but they would be expected if cognition for physical action is fundamentally similar to cognition for higher-level decision-making. To test for such effects, we asked participants to reach for a horizontally-oriented pipe to move it from one height to another while turning the pipe 180° to bring one end (the "business end") to a target on the left or right. From a physical perspective, participants could have always rotated the pipe in the same angular direction no matter which end was the business end; a given participant could have always turned the pipe clockwise or counter-clockwise. Instead, our participants turned the business end counter-clockwise for left targets and clockwise for right targets. Thus, the way the identical physical task was framed altered the way it was performed. This finding is consistent with the hypothesis that cognition for physical action is fundamentally similar to cognition for higher-level decision-making. A tantalizing possibility is that higher-level decision heuristics have roots in the control of physical action, a hypothesis that accords with embodied views of cognition. PMID:26970853

  6. Frame architecture for video servers

    NASA Astrophysics Data System (ADS)

    Venkatramani, Chitra; Kienzle, Martin G.

    1999-11-01

    Video is inherently frame-oriented and most applications such as commercial video processing require to manipulate video in terms of frames. However, typical video servers treat videos as byte streams and perform random access based on approximate byte offsets to be supplied by the client. They do not provide frame or timecode oriented API which is essential for many applications. This paper describes a frame-oriented architecture for video servers. It also describes the implementation in the context of IBM's VideoCharger server. The later part of the paper describes an application that uses the frame architecture and provides fast and slow-motion scanning capabilities to the server.

  7. Scarcity frames value.

    PubMed

    Shah, Anuj K; Shafir, Eldar; Mullainathan, Sendhil

    2015-04-01

    Economic models of decision making assume that people have a stable way of thinking about value. In contrast, psychology has shown that people's preferences are often malleable and influenced by normatively irrelevant contextual features. Whereas economics derives its predictions from the assumption that people navigate a world of scarce resources, recent psychological work has shown that people often do not attend to scarcity. In this article, we show that when scarcity does influence cognition, it renders people less susceptible to classic context effects. Under conditions of scarcity, people focus on pressing needs and recognize the trade-offs that must be made against those needs. Those trade-offs frame perception more consistently than irrelevant contextual cues, which exert less influence. The results suggest that scarcity can align certain behaviors more closely with traditional economic predictions. PMID:25676256

  8. Semiclassical framed BPS states

    NASA Astrophysics Data System (ADS)

    Moore, Gregory W.; Royston, Andrew B.; Van den Bleeken, Dieter

    2016-07-01

    We provide a semiclassical description of framed BPS states in four-dimensional {N}=2 super Yang-Mills theories probed by 't Hooft defects, in terms of a supersymmetric quantum mechanics on the moduli space of singular monopoles. Framed BPS states, like their ordinary counterparts in the theory without defects, are associated with the L 2 kernel of certain Dirac operators on moduli space, or equivalently with the L 2 cohomology of related Dolbeault operators. The Dirac/Dolbeault operators depend on two Cartan-valued Higgs vevs. We conjecture a map between these vevs and the Seiberg-Witten special coordinates, consistent with a one-loop analysis and checked in examples. The map incorporates all perturbative and nonperturbative corrections that are relevant for the semiclassical construction of BPS states, over a suitably defined weak coupling regime of the Coulomb branch. We use this map to translate wall crossing formulae and the no-exotics theorem to statements about the Dirac/Dolbeault operators. The no-exotics theorem, concerning the absence of nontrivial SU(2) R representations in the BPS spectrum, implies that the kernel of the Dirac operator is chiral, and further translates into a statement that all L 2 cohomology of the Dolbeault operator is concentrated in the middle degree. Wall crossing formulae lead to detailed predictions for where the Dirac operators fail to be Fredholm and how their kernels jump. We explore these predictions in nontrivial examples. This paper explains the background and arguments behind the results announced in the short note [1].

  9. Microlens frames for laser diode arrays

    DOEpatents

    Skidmore, J.A.; Freitas, B.L.

    1999-07-13

    Monolithic microlens frames enable the fabrication of monolithic laser diode arrays and are manufactured inexpensively with high registration, and with inherent focal length compensation for any lens diameter variation. A monolithic substrate is used to fabricate a low-cost microlens array. The substrate is wet-etched or sawed with a series of v-grooves. The v-grooves can be created by wet-etching, by exploiting the large etch-rate selectivity of different crystal planes. The v-grooves provide a support frame for either cylindrical or custom-shaped microlenses. Because the microlens frames are formed by photolithographic semiconductor batch-processing techniques, they can be formed inexpensively over large areas with precise lateral and vertical registration. The v-groove has an important advantage for preserving the correct focus for lenses of varying diameter. 12 figs.

  10. Microlens frames for laser diode arrays

    DOEpatents

    Skidmore, Jay A.; Freitas, Barry L.

    1999-01-01

    Monolithic microlens frames enable the fabrication of monolithic laser diode arrays and are manufactured inexpensively with high registration, and with inherent focal length compensation for any lens diameter variation. A monolithic substrate is used to fabricate a low-cost microlens array. The substrate is wet-etched or sawed with a series of v-grooves. The v-grooves can be created by wet-etching, by exploiting the large etch-rate selectivity of different crystal planes. The v-grooves provide a support frame for either cylindrical or custom-shaped microlenses. Because the microlens frames are formed by photolithographic semiconductor batch-processing techniques, they can be formed inexpensively over large areas with precise lateral and vertical registration. The v-groove has an important advantage for preserving the correct focus for lenses of varying diameter.

  11. Physics of Non-Inertial Reference Frames

    NASA Astrophysics Data System (ADS)

    Kamalov, Timur F.

    2010-12-01

    Physics of non-inertial reference frames is a generalizing of Newton's laws to any reference frames. It is the system of general axioms for classical and quantum mechanics. The first, Kinematics Principle reads: the kinematic state of a body free of forces conserves and equal in absolute value to an invariant of the observer's reference frame. The second, Dynamics Principle extended Newton's second law to non-inertial reference frames and also contains additional variables there are higher derivatives of coordinates. Dynamics Principle reads: a force induces a change in the kinematic state of the body and is proportional to the rate of its change. It is mean that if the kinematic invariant of the reference frame is n-th derivative with respect the time, then the dynamics of a body being affected by the force F is described by the 2n-th differential equation. The third, Statics Principle reads: the sum of all forces acting a body at rest is equal to zero.

  12. Physics of Non-Inertial Reference Frames

    SciTech Connect

    Kamalov, Timur F.

    2010-12-22

    Physics of non-inertial reference frames is a generalizing of Newton's laws to any reference frames. It is the system of general axioms for classical and quantum mechanics. The first, Kinematics Principle reads: the kinematic state of a body free of forces conserves and equal in absolute value to an invariant of the observer's reference frame. The second, Dynamics Principle extended Newton's second law to non-inertial reference frames and also contains additional variables there are higher derivatives of coordinates. Dynamics Principle reads: a force induces a change in the kinematic state of the body and is proportional to the rate of its change. It is mean that if the kinematic invariant of the reference frame is n-th derivative with respect the time, then the dynamics of a body being affected by the force F is described by the 2n-th differential equation. The third, Statics Principle reads: the sum of all forces acting a body at rest is equal to zero.

  13. MRI Contrasts in High Rank Rotating Frames

    PubMed Central

    Liimatainen, Timo; Hakkarainen, Hanne; Mangia, Silvia; Huttunen, Janne M.J.; Storino, Christine; Idiyatullin, Djaudat; Sorce, Dennis; Garwood, Michael; Michaeli, Shalom

    2014-01-01

    Purpose MRI relaxation measurements are performed in the presence of a fictitious magnetic field in the recently described technique known as RAFF (Relaxation Along a Fictitious Field). This method operates in the 2nd rotating frame (rank n = 2) by utilizing a non-adiabatic sweep of the radiofrequency effective field to generate the fictitious magnetic field. In the present study, the RAFF method is extended for generating MRI contrasts in rotating frames of ranks 1 ≤ n ≤ 5. The developed method is entitled RAFF in rotating frame of rank n (RAFFn). Methods RAFFn pulses were designed to generate fictitious fields that allow locking of magnetization in rotating frames of rank n. Contrast generated with RAFFn was studied using Bloch-McConnell formalism together with experiments on human and rat brains. Results Tolerance to B0 and B1 inhomogeneities and reduced specific absorption rate with increasing n in RAFFn were demonstrated. Simulations of exchange-induced relaxations revealed enhanced sensitivity of RAFFn to slow exchange. Consistent with such feature, an increased grey/white matter contrast was observed in human and rat brain as n increased. Conclusion RAFFn is a robust and safe rotating frame relaxation method to access slow molecular motions in vivo. PMID:24523028

  14. STARS[R] Spring 2012 Quarterly Review: Framing Campus Sustainability

    ERIC Educational Resources Information Center

    Urbanski, Monika

    2012-01-01

    The Spring 2012 SQR: "Framing Campus Sustainability," features stories that frame the evolving concept of sustainability in higher education. Included in this issue are a snapshot of ratings-to-date, a focus on credits within the Operations (OP) category, and insights into how institutions are defining and interpreting the evolving concepts of…

  15. Virtual Frame Buffer Interface Program

    NASA Technical Reports Server (NTRS)

    Wolfe, Thomas L.

    1990-01-01

    Virtual Frame Buffer Interface program makes all frame buffers appear as generic frame buffer with specified set of characteristics, allowing programmers to write codes that run unmodified on all supported hardware. Converts generic commands to actual device commands. Consists of definition of capabilities and FORTRAN subroutines called by application programs. Developed in FORTRAN 77 for DEC VAX 11/780 or DEC VAX 11/750 computer under VMS 4.X.

  16. Cultural background shapes spatial reference frame proclivity

    PubMed Central

    Goeke, Caspar; Kornpetpanee, Suchada; Köster, Moritz; Fernández-Revelles, Andrés B.; Gramann, Klaus; König, Peter

    2015-01-01

    Spatial navigation is an essential human skill that is influenced by several factors. The present study investigates how gender, age, and cultural background account for differences in reference frame proclivity and performance in a virtual navigation task. Using an online navigation study, we recorded reaction times, error rates (confusion of turning axis), and reference frame proclivity (egocentric vs. allocentric reference frame) of 1823 participants. Reaction times significantly varied with gender and age, but were only marginally influenced by the cultural background of participants. Error rates were in line with these results and exhibited a significant influence of gender and culture, but not age. Participants’ cultural background significantly influenced reference frame selection; the majority of North-Americans preferred an allocentric strategy, while Latin-Americans preferred an egocentric navigation strategy. European and Asian groups were in between these two extremes. Neither the factor of age nor the factor of gender had a direct impact on participants’ navigation strategies. The strong effects of cultural background on navigation strategies without the influence of gender or age underlines the importance of socialized spatial cognitive processes and argues for socio-economic analysis in studies investigating human navigation. PMID:26073656

  17. Backreaction of frame dragging

    SciTech Connect

    Herdeiro, Carlos A. R.; Rebelo, Carmen; Warnick, Claude M.

    2009-10-15

    The backreaction on black holes due to dragging heavy, rather than test, objects is discussed. As a case study, a five-dimensional regular black Saturn system where the central black hole has vanishing intrinsic angular momentum, J{sup BH}=0, is considered. It is shown that there is a correlation between the sign of two response functions. One is interpreted as a moment of inertia of the black ring in the black Saturn system. The other measures the variation of the black ring horizon angular velocity with the central black hole mass, for fixed ring mass and angular momentum. The two different phases defined by these response functions collapse, for small central black hole mass, to the thin and fat ring phases. In the fat phase, the zero area limit of the black Saturn ring has reduced spin j{sup 2}>1, which is related to the behavior of the ring angular velocity. Using the 'gravitomagnetic clock effect', for which a universality property is exhibited, it is shown that frame dragging measured by an asymptotic observer decreases, in both phases, when the central black hole mass increases, for fixed ring mass and angular momentum. A close parallelism between the results for the fat phase and those obtained recently for the double Kerr solution is drawn, considering also a regular black Saturn system with J{sup BH}{ne}0.

  18. Optical characterization of frame grabbers

    NASA Astrophysics Data System (ADS)

    Pozo, A. M.; Rubiño, M.

    2013-04-01

    Today, video cameras connected to frame grabbers are used in many applications such as traffic control, surveillance, medical systems or machine vision. In this work, we present an optical characterization of frame grabbers in terms of their spatial-frequency responses. This characterization is based on the modulation transfer function (MTF) determination from speckle patterns using a low-cost experimental setup. We have characterized and compared three different frame grabbers. The three frame grabbers produce an amplification (boost) in the horizontal MTF in different spatial-frequency ranges and having different maximum amplification values.

  19. Advanced Wall Framing; BTS Technology Fact Sheet

    SciTech Connect

    Southface Energy Institute; Tromly, K.

    2000-11-07

    Advanced framing techniques for home construction have been researched extensively and proven effective. Both builders and home owners can benefit from advanced framing. Advanced framing techniques create a structurally sound home that has lower material and labor costs than a conventionally framed house. This fact sheet describes advanced framing techniques, design considerations, and framing.

  20. Improvement of the atmospheric discharge laser-triggered ability using multiple pulses from a kilohertz KrF laser

    SciTech Connect

    Yamaura, Michiteru

    2005-08-15

    The potential ability of lasers to control lightning can be improved by using a train of pulses with submillisecond separations. Laser-triggered experiments in a small-scale (10-mm gap) atmospheric discharge facility show that the triggering is dramatically enhanced when a five-pulse train of sub-Joule energy is used instead of a single pulse. This effect increases rapidly as the pulse interval is reduced. It appears that at a submillisecond pulse interval, sufficient positive and negative ions survive in subsequent pulses, thus enabling easy deionization. Hence, significant plasma buildup occurs from one pulse to the next. However, this persistence of ions would appear to imply that the rate of recombination (effectively a charge transfer between ions) is considerably lower than previously believed.

  1. Stable kilo-hertz electro-optically Q-switched Tm,Ho:YAP laser at room temperature

    NASA Astrophysics Data System (ADS)

    Liu, C.; Zhao, S.; Li, Y.; Yang, K.; Li, M.; Li, G.; Li, D.; Li, T.; Qiao, W.; Feng, T.; Chen, X.; Zheng, L.; Su, L.; Xu, J.

    2016-07-01

    A diode-pumped Tm,Ho:YAP laser utilizing a self-made LiNbO3 (LN) electro-optically modulator (EOM) at room temperature is demonstrated for the first time. A minimum pulse duration of 107.4 ns was obtained at a pulse repetition rate (PRR) of 200 Hz, giving a maximum single pulse energy of 1.65 mJ. At a PRR of 1 kHz, pulse duration of 145.8 ns was achieved under the absorbed pump power of 7.4 W, corresponding to a maximum single pulse energy of 0.546 mJ, and the pulse to pulse amplitude instabilities were measured to be about 4.6% and 5.83% for PRRs of 200 Hz and 1 kHz, respectively.

  2. FRAMES and Other IEM Technologies

    EPA Science Inventory

    A presentation package is developed that describes the FRAMES software technology system. The philosophy of FRAMES is discussed; its components and editors are reviewed; its relationship to integrated environmental modeling technologies; such as D4EM and SuperMUSE, are described;...

  3. Framed School--Frame Factors, Frames and the Dynamics of Social Interaction in School

    ERIC Educational Resources Information Center

    Persson, Anders

    2015-01-01

    This paper aims to show how the Goffman frame perspective can be used in an analysis of school and education and how it can be combined, in such analysis, with the frame factor perspective. The latter emphasizes factors that are determined outside the teaching process, while the former stresses how actors organize their experiences and define…

  4. Framing Obesity: How News Frames Shape Attributions and Behavioral Responses.

    PubMed

    Sun, Ye; Krakow, Melinda; John, Kevin K; Liu, Miao; Weaver, Jeremy

    2016-01-01

    Based on a public health model of obesity, this study set out to examine whether a news article reporting the obesity issue in a societal versus individual frame would increase perceptions of societal responsibilities for the obesity problem and motivate responsibility-taking behaviors. Responsibility-taking behaviors were examined at 3 levels: personal, interpersonal, and societal. Data from a Web-based experiment revealed significant framing effects on behaviors via causal and treatment responsibility attributions. The societal frame increased societal causal and treatment attribution, which led to greater likelihoods of interpersonal and social responsibility-taking behaviors as well as personal behaviors. Our findings suggest that news framing can be an effective venue for raising awareness of obesity as a societal issue and mobilizing collective efforts. PMID:26375052

  5. DRIFT: an analysis of outcome framing in intertemporal choice.

    PubMed

    Read, Daniel; Frederick, Shane; Scholten, Marc

    2013-03-01

    People prefer to receive good outcomes immediately rather than wait, and they must be compensated for waiting. But what influences their decision about how much compensation is required for a given wait? To give a partial answer to this question, we develop the DRIFT model, a heuristic description of how framing influences intertemporal choice. We describe 4 experiments showing the implications of this model. In the experiments, we vary how the difference between a smaller sooner outcome and a larger later outcome is framed-either as total interest earned, as an interest rate, or as total amount earned (the conventional frame in studies of intertemporal choice)-and whether the larger later outcome is described as resulting from the investment of the smaller sooner one. These alternate frames have several effects. First, the investment language increases patience. Second, the explicit provision of the (otherwise implicit) experimental interest rate sharply reduces the magnitude effect. Correspondingly, we find that interest frames increase patience when the rewards are small, but they decrease patience when they are large. Third, the interest-rate frame induces somewhat greater discounting for longer time periods and, thus, reverses the common finding of "hyperbolic" discounting. Thus, many of the "stylized facts" implied by studies involving choices between a smaller sooner and a larger later amount are eliminated or reverse under alternate outcome frames. PMID:22866891

  6. Dragging of inertial frames inside the rotating neutron stars

    SciTech Connect

    Chakraborty, Chandrachur; Modak, Kamakshya Prasad; Bandyopadhyay, Debades E-mail: kamakshya.modak@saha.ac.in

    2014-07-20

    We derive the exact frame-dragging rate inside rotating neutron stars. This formula is applied to show that the frame-dragging rate monotonically decreases from the center to the surface of the neutron star along the pole. In the case of the frame-dragging rate along the equatorial distance, it decreases initially away from the center, becomes negligibly small well before the surface of the neutron star, rises again, and finally approaches to a small value at the surface. The appearance of a local maximum and minimum in this case is the result of the dependence of frame-dragging frequency on the distance and angle. Moving from the equator to the pole, it is observed that this local maximum and minimum in the frame-dragging rate along the equator disappear after crossing a critical angle. It is also noted that the positions of the local maximum and minimum of the frame-dragging rate along the equator depend on the rotation frequency and central energy density of a particular pulsar.

  7. Framing the patent troll debate.

    PubMed

    Risch, Michael

    2014-02-01

    The patent troll debate has reached a fevered pitch in the USA. This editorial seeks to frame the debate by pointing out the lack of clarity in defining patent trolls and their allegedly harmful actions. It then frames the debate by asking currently unanswered questions: Where do troll patents come from? What are the effects of troll assertions? Will policy changes improve the system? PMID:24354803

  8. Ties Between Celestial And Planetary Reference Frames

    NASA Technical Reports Server (NTRS)

    Finger, Mark H.; Folkner, William M.

    1992-01-01

    Report presents new determination of relative orientation (or frame tie) between reference frame of extra-galactic radio sources and reference frame of planetary ephemeris. Method employed for improved frame-tie estimate relies on ability to measure orientation of Earth with respect to inertial reference frame. Improves orbit determination for interplanetary spacecraft.

  9. Coding scheme for wireless video transport with reduced frame skipping

    NASA Astrophysics Data System (ADS)

    Aramvith, Supavadee; Sun, Ming-Ting

    2000-05-01

    We investigate the scenario of using the Automatic Repeat reQuest (ARQ) retransmission scheme for two-way low bit-rate video communications over wireless Rayleigh fading channels. We show that during the retransmission of error packets, due to the reduced channel throughput, the video encoder buffer may fill-up quickly and cause the TMN8 rate-control algorithm to significantly reduce the bits allocated to each video frame. This results in Peak Signal-to-Noise Ratio (PSNR) degradation and many skipper frames. To reduce the number of frames skipped, in this paper we propose a coding scheme which takes into consideration the effects of the video buffer fill-up, an a priori channel model, the channel feedback information, and hybrid ARQ/FEC. The simulation results indicate that our proposed scheme encode the video sequences with much fewer frame skipping and with higher PSNR compared to H.263 TMN8.

  10. Hamiltonian approach to frame dragging

    NASA Astrophysics Data System (ADS)

    Epstein, Kenneth J.

    2008-07-01

    A Hamiltonian approach makes the phenomenon of frame dragging apparent “up front” from the appearance of the drag velocity in the Hamiltonian of a test particle in an arbitrary metric. Hamiltonian (1) uses the inhomogeneous force equation (4), which applies to non-geodesic motion as well as to geodesics. The Hamiltonian is not in manifestly covariant form, but is covariant because it is derived from Hamilton’s manifestly covariant scalar action principle. A distinction is made between manifest frame dragging such as that in the Kerr metric, and hidden frame dragging that can be made manifest by a coordinate transformation such as that applied to the Robertson-Walker metric in Sect. 2. In Sect. 3 a zone of repulsive gravity is found in the extreme Kerr metric. Section 4 treats frame dragging in special relativity as a manifestation of the equivalence principle in accelerated frames. It answers a question posed by Bell about how the Lorentz contraction can break a thread connecting two uniformly accelerated rocket ships. In Sect. 5 the form of the Hamiltonian facilitates the definition of gravitomagnetic and gravitoelectric potentials.

  11. Space-Frame Lunar Lander

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A.

    2010-01-01

    The space-frame lunar lander was originally intended to (1) land on rough lunar terrain, (2) deform itself to conform to the terrain so as to be able to remain there in a stable position and orientation, and (3) if required, further deform itself to perform various functions. In principle, the space-frame lunar lander could be used in the same way on Earth, as might be required, for example, to place meteorological sensors or a radio-communication relay station on an otherwise inaccessible mountain peak. the space-frame lunar lander would include a truss-like structure consisting mostly of a tetrahedral mesh of nodes connected by variable-length struts, the lengths of which would be altered in coordination to impart the desired overall size and shape to the structure. Thrusters (that is, small rocket engines), propellant tanks, a control system, and instrumentation would be mounted in and on the structure (see figure). Once it had landed and deformed itself to the terrain through coordinated variations in the lengths of the struts, the structure could be further deformed into another space-frame structure

  12. SEOS frame camera applications study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A research and development satellite is discussed which will provide opportunities for observation of transient phenomena that fall within the fixed viewing circle of the spacecraft. The evaluation of possible applications for frame cameras, for SEOS, are studied. The computed lens characteristics for each camera are listed.

  13. Epistemic Frames for Epistemic Games

    ERIC Educational Resources Information Center

    Shaffer, David W.

    2006-01-01

    This paper, develops the concept of "epistemic frames" as a mechanism through which students can use experiences in video games, computer games, and other interactive learning environments to help them deal more effectively with situations outside of the original context of learning. Building on ideas of "islands of expertise" [Crowley, K., &…

  14. Plasma physics in noninertial frames

    SciTech Connect

    Thyagaraja, A.; McClements, K. G.

    2009-09-15

    Equations describing the nonrelativistic motion of a charged particle in an arbitrary noninertial reference frame are derived from the relativistically invariant form of the particle action. It is shown that the equations of motion can be written in the same form in inertial and noninertial frames, with the effective electric and magnetic fields in the latter modified by inertial effects associated with centrifugal and Coriolis accelerations. These modifications depend on the particle charge-to-mass ratio, and also the vorticity, specific kinetic energy, and compressibility of the frame flow. The Newton-Lorentz, Vlasov, and Fokker-Planck equations in such a frame are derived. Reduced models such as gyrokinetic, drift-kinetic, and fluid equations are then derivable from these equations in the appropriate limits, using standard averaging procedures. The results are applied to tokamak plasmas rotating about the machine symmetry axis with a nonrelativistic but otherwise arbitrary toroidal flow velocity. Astrophysical applications of the analysis are also possible since the power of the action principle is such that it can be used to describe relativistic flows in curved spacetime.

  15. Examining the Linkage Between FRAMES and GMS

    SciTech Connect

    Whelan, Gene; Castleton, Karl J.

    2006-02-13

    Because GMS provides so many features, of which some are also addressed by FRAMES, it could represent a platform to link to FRAMES, or FRAMES could represent a platform to link to GMS. The focus of this summary is to examine the strengths and weaknesses of the potential linkage direction and provide recommendations for the linkage between FRAMES and GMS.

  16. Astrophysics of Reference Frame Tie Objects

    NASA Technical Reports Server (NTRS)

    Johnston, Kenneth J.; Boboltz, David; Fey, Alan Lee; Gaume, Ralph A.; Zacharias, Norbert

    2004-01-01

    The Astrophysics of Reference Frame Tie Objects Key Science program will investigate the underlying physics of SIM grid objects. Extragalactic objects in the SIM grid will be used to tie the SIM reference frame to the quasi-inertial reference frame defined by extragalactic objects and to remove any residual frame rotation with respect to the extragalactic frame. The current realization of the extragalactic frame is the International Celestial Reference Frame (ICRF). The ICRF is defined by the radio positions of 212 extragalactic objects and is the IAU sanctioned fundamental astronomical reference frame. This key project will advance our knowledge of the physics of the objects which will make up the SIM grid, such as quasars and chromospherically active stars, and relates directly to the stability of the SIM reference frame. The following questions concerning the physics of reference frame tie objects will be investigated.

  17. Dispositional optimism, self-framing and medical decision-making.

    PubMed

    Zhao, Xu; Huang, Chunlei; Li, Xuesong; Zhao, Xin; Peng, Jiaxi

    2015-03-01

    Self-framing is an important but underinvestigated area in risk communication and behavioural decision-making, especially in medical settings. The present study aimed to investigate the relationship among dispositional optimism, self-frame and decision-making. Participants (N = 500) responded to the Life Orientation Test-Revised and self-framing test of medical decision-making problem. The participants whose scores were higher than the middle value were regarded as highly optimistic individuals. The rest were regarded as low optimistic individuals. The results showed that compared to the high dispositional optimism group, participants from the low dispositional optimism group showed a greater tendency to use negative vocabulary to construct their self-frame, and tended to choose the radiation therapy with high treatment survival rate, but low 5-year survival rate. Based on the current findings, it can be concluded that self-framing effect still exists in medical situation and individual differences in dispositional optimism can influence the processing of information in a framed decision task, as well as risky decision-making. PMID:24849872

  18. Fast frame scanning camera system for light-sheet microscopy.

    PubMed

    Wu, Di; Zhou, Xing; Yao, Baoli; Li, Runze; Yang, Yanlong; Peng, Tong; Lei, Ming; Dan, Dan; Ye, Tong

    2015-10-10

    In the interest of improving the temporal resolution for light-sheet microscopy, we designed a fast frame scanning camera system that incorporated a galvanometer scanning mirror into the imaging path of a home-built light-sheet microscope. This system transformed a temporal image sequence to a spatial one so that multiple images could be acquired during one exposure period. The improvement factor of the frame rate was dependent on the number of sub-images that could be tiled on the sensor without overlapping each other and was therefore a trade-off with the image size. As a demonstration, we achieved 960 frames/s (fps) on a CCD camera that was originally capable of recording images at only 30 fps (full frame). This allowed us to observe millisecond or sub-millisecond events with ordinary CCD cameras. PMID:26479797

  19. Nine Frames as Jupiter Turns

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This sequence of nine true-color, narrow-angle images shows the varying appearance of Jupiter as it rotated through more than a complete 360-degree turn. The smallest features seen in this sequence are no bigger than about 380 kilometers (about 236 miles). Rotating more than twice as fast as Earth, Jupiter completes one rotation in about 10 hours. These images were taken on Oct. 22 and 23, 2000. From image to image (proceeding left to right across each row and then down to the next row), cloud features on Jupiter move from left to right before disappearing over the edge onto the nightside of the planet. The most obvious Jovian feature is the Great Red Spot, which can be seen moving onto the dayside in the third frame (below and to the left of the center of the planet). In the fourth frame, taken about 1 hour and 40 minutes later, the Great Red Spot has been carried by the planet's rotation to the east and does not appear again until the final frame, which was taken one complete rotation after the third frame.

    Unlike weather systems on Earth, which change markedly from day to day, large cloud systems in Jupiter's colder, thicker atmosphere are long-lived, so the two frames taken one rotation apart have a very similar appearance. However, when this sequence of images is eventually animated, strong winds blowing eastward at some latitudes and westward at other latitudes will be readily apparent. The results of such differential motions can be seen even in the still frames shown here. For example, the clouds of the Great Red Spot rotate counterclockwise. The strong westward winds northeast of the Great Red Spot are deflected around the spot and form a wake of turbulent clouds downstream (visible in the fourth image), just as a rock in a rapidly flowing river deflects the fluid around it.

    The equatorial zone on Jupiter is currently bright white, indicating the presence of clouds much like cirrus clouds on Earth, but made of ammonia instead of water ice. This

  20. New frame 8 generator from Newage

    SciTech Connect

    Mullins, P.

    1995-11-01

    Newage International is now in full production with a new range of generators developed in response to the trend towards bigger, more powerful turbo diesels and the growing use of industrial gas turbines. Designated Frame 8, the series is the most powerful yet produced by the Stamford, England-based company, with low-voltage ratings extending to 3125 kVA and medium- and high-voltage ratings available up to 13.8 kV. The company says the new range will be an option for combined heat and power (CHP), standby and interruptible power installations. The new generators incorporate a great deal of new technology. The familiar PMG (permanent magnet generator) control system developed by Newage now incorporates a new higher-powered AVR - the MA325. This is fitted as standard to both marine and industrial machines. This article points out the salient features of this new generator.

  1. Reference-frame-independent quantum key distribution

    SciTech Connect

    Laing, Anthony; Rarity, John G.; O'Brien, Jeremy L.; Scarani, Valerio

    2010-07-15

    We describe a quantum key distribution protocol based on pairs of entangled qubits that generates a secure key between two partners in an environment of unknown and slowly varying reference frame. A direction of particle delivery is required, but the phases between the computational basis states need not be known or fixed. The protocol can simplify the operation of existing setups and has immediate applications to emerging scenarios such as earth-to-satellite links and the use of integrated photonic waveguides. We compute the asymptotic secret key rate for a two-qubit source, which coincides with the rate of the six-state protocol for white noise. We give the generalization of the protocol to higher-dimensional systems and detail a scheme for physical implementation in the three-dimensional qutrit case.

  2. Lattice QCD in rotating frames.

    PubMed

    Yamamoto, Arata; Hirono, Yuji

    2013-08-23

    We formulate lattice QCD in rotating frames to study the physics of QCD matter under rotation. We construct the lattice QCD action with the rotational metric and apply it to the Monte Carlo simulation. As the first application, we calculate the angular momenta of gluons and quarks in the rotating QCD vacuum. This new framework is useful to analyze various rotation-related phenomena in QCD. PMID:24010426

  3. Ultra-fast framing camera tube

    DOEpatents

    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.

  4. A-frame model for metaphor

    SciTech Connect

    Kilpatrick, W.

    1982-01-01

    While literal language is successfully being subjected to automatic analysis, metaphors remain intractable. Using Minsky's frame theory the metaphoric process is viewed as a copying of stereotypic terminal clusters from the frames of the 1 degrees and 2 degrees terms of the metaphor. Stereotypic values from the two original frames share equal status in this new frame, while non-stereotypic values from the two will be kept separate for possible use in metaphoric extension. The a-frame analysis is illustrated by application to non-literary novel metaphors. Frames provide the quantity of information needed for interpretation. Certain frame values are marked as stereotypic. Creativity is realized by the construction of a new a-frame, and the tension is realized by the presence in a single a-frame of both shared stereotypic and discrete non-stereotypic values. 10 references.

  5. The Kepler Full Frame Images

    NASA Astrophysics Data System (ADS)

    Dotson, Jessie L.; Batalha, N.; Bryson, S.; Caldwell, D. A.; Clarke, B.; Haas, M. R.; Jenkins, J.; Kolodziejczak, J.; Quintana, E.; Van Cleve, J.; Kepler Team

    2010-01-01

    NASA's exoplanet discovery mission Kepler provides uninterrupted 1-min and 30-min optical photometry of a 100 square degree field over a 3.5 yr nominal mission. Downlink bandwidth is filled at these short cadences by selecting only detector pixels specific to 105 preselected stellar targets. The majority of the Kepler field, comprising 4 x 106 mv < 20 sources, is sampled at much lower 1-month cadence in the form of a full-frame image. The Full Frame Images (FFIs) are calibrated by the Science Operations Center at NASA Ames Research Center. The Kepler Team employ these images for astrometric and photometric reference but make the images available to the astrophysics community through the Multimission Archive at STScI (MAST). The full-frame images provide a resource for potential Kepler Guest Observers to select targets and plan observing proposals, while also providing a freely-available long-cadence legacy of photometric variation across a swathe of the Galactic disk. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.

  6. The Kepler Full Frame Images

    NASA Technical Reports Server (NTRS)

    Dotson, Jessie L.; Batalha, Natalie; Bryson, Stephen T.; Caldwell, Douglas A.; Clarke, Bruce D.

    2010-01-01

    NASA's exoplanet discovery mission Kepler provides uninterrupted 1-min and 30-min optical photometry of a 100 square degree field over a 3.5 yr nominal mission. Downlink bandwidth is filled at these short cadences by selecting only detector pixels specific to 105 preselected stellar targets. The majority of the Kepler field, comprising 4 x 10(exp 6) m_v < 20 sources, is sampled at much lower 1-month cadence in the form of a full-frame image. The Full Frame Images (FFIs) are calibrated by the Science Operations Center at NASA Ames Research Center. The Kepler Team employ these images for astrometric and photometric reference but make the images available to the astrophysics community through the Multimission Archive at STScI (MAST). The full-frame images provide a resource for potential Kepler Guest Observers to select targets and plan observing proposals, while also providing a freely-available long-cadence legacy of photometric variation across a swathe of the Galactic disk.

  7. Framed Morse functions on surfaces

    SciTech Connect

    Kudryavtseva, Elena A; Permyakov, Dmitrii A

    2010-06-09

    Let M be a smooth, compact, not necessarily orientable surface with (maybe empty) boundary, and let F be the space of Morse functions on M that are constant on each component of the boundary and have no critical points at the boundary. The notion of framing is defined for a Morse function f element of F. In the case of an orientable surface M this is a closed 1-form {alpha} on M with punctures at the critical points of local minimum and maximum of f such that in a neighbourhood of each critical point the pair (f,{alpha}) has a canonical form in a suitable local coordinate chart and the 2-form df and {alpha} does not vanish on M punctured at the critical points and defines there a positive orientation. Each Morse function on M is shown to have a framing, and the space F endowed with the C{sup {infinity}-}topology is homotopy equivalent to the space F of framed Morse functions. The results obtained make it possible to reduce the problem of describing the homotopy type of F to the simpler problem of finding the homotopy type of F. As a solution of the latter, an analogue of the parametric h-principle is stated for the space F. Bibliography: 41 titles.

  8. Monolithic LTCC seal frame and lid

    DOEpatents

    Krueger, Daniel S.; Peterson, Kenneth A.; Stockdale, Dave; Duncan, James Brent; Riggs, Bristen

    2016-06-21

    A method for forming a monolithic seal frame and lid for use with a substrate and electronic circuitry comprises the steps of forming a mandrel from a ceramic and glass based material, forming a seal frame and lid block from a ceramic and glass based material, creating a seal frame and lid by forming a compartment and a plurality of sidewalls in the seal frame and lid block, placing the seal frame and lid on the mandrel such that the mandrel fits within the compartment, and cofiring the seal frame and lid block.

  9. Framing and global health governance: key findings.

    PubMed

    McInnes, Colin; Lee, Kelley

    2012-01-01

    Despite widespread agreement that collective action to address shared health challenges across countries is desirable and necessary, the realm of global health governance has remained highly problematic. A key reason for this is the manner in which health issues are presented ('framed'). Because multiple frames are operating simultaneously, confusion and a range of competing policy recommendations and priorities result. Drawing on the previous articles published in this Special Supplement, these key findings explore how health issues are framed, what makes a framing successful, what frames are used for and what effects framing has. PMID:23088193

  10. Mars Science Laboratory Frame Manager for Centralized Frame Tree Database and Target Pointing

    NASA Technical Reports Server (NTRS)

    Kim, Won S.; Leger, Chris; Peters, Stephen; Carsten, Joseph; Diaz-Calderon, Antonio

    2013-01-01

    The FM (Frame Manager) flight software module is responsible for maintaining the frame tree database containing coordinate transforms between frames. The frame tree is a proper tree structure of directed links, consisting of surface and rover subtrees. Actual frame transforms are updated by their owner. FM updates site and saved frames for the surface tree. As the rover drives to a new area, a new site frame with an incremented site index can be created. Several clients including ARM and RSM (Remote Sensing Mast) update their related rover frames that they own. Through the onboard centralized FM frame tree database, client modules can query transforms between any two frames. Important applications include target image pointing for RSM-mounted cameras and frame-referenced arm moves. The use of frame tree eliminates cumbersome, error-prone calculations of coordinate entries for commands and thus simplifies flight operations significantly.