WorldWideScience

Sample records for camera dynamic range

  1. Image Alignment for Multiple Camera High Dynamic Range Microscopy.

    Science.gov (United States)

    Eastwood, Brian S; Childs, Elisabeth C

    2012-01-09

    This paper investigates the problem of image alignment for multiple camera high dynamic range (HDR) imaging. HDR imaging combines information from images taken with different exposure settings. Combining information from multiple cameras requires an alignment process that is robust to the intensity differences in the images. HDR applications that use a limited number of component images require an alignment technique that is robust to large exposure differences. We evaluate the suitability for HDR alignment of three exposure-robust techniques. We conclude that image alignment based on matching feature descriptors extracted from radiant power images from calibrated cameras yields the most accurate and robust solution. We demonstrate the use of this alignment technique in a high dynamic range video microscope that enables live specimen imaging with a greater level of detail than can be captured with a single camera.

  2. Image Alignment for Multiple Camera High Dynamic Range Microscopy

    OpenAIRE

    Eastwood, Brian S.; Childs, Elisabeth C.

    2012-01-01

    This paper investigates the problem of image alignment for multiple camera high dynamic range (HDR) imaging. HDR imaging combines information from images taken with different exposure settings. Combining information from multiple cameras requires an alignment process that is robust to the intensity differences in the images. HDR applications that use a limited number of component images require an alignment technique that is robust to large exposure differences. We evaluate the suitability fo...

  3. High dynamic range image acquisition based on multiplex cameras

    Science.gov (United States)

    Zeng, Hairui; Sun, Huayan; Zhang, Tinghua

    2018-03-01

    High dynamic image is an important technology of photoelectric information acquisition, providing higher dynamic range and more image details, and it can better reflect the real environment, light and color information. Currently, the method of high dynamic range image synthesis based on different exposure image sequences cannot adapt to the dynamic scene. It fails to overcome the effects of moving targets, resulting in the phenomenon of ghost. Therefore, a new high dynamic range image acquisition method based on multiplex cameras system was proposed. Firstly, different exposure images sequences were captured with the camera array, using the method of derivative optical flow based on color gradient to get the deviation between images, and aligned the images. Then, the high dynamic range image fusion weighting function was established by combination of inverse camera response function and deviation between images, and was applied to generated a high dynamic range image. The experiments show that the proposed method can effectively obtain high dynamic images in dynamic scene, and achieves good results.

  4. Picosecond X-ray streak camera dynamic range measurement

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-15

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

  5. High Precision Sunphotometer using Wide Dynamic Range (WDR) Camera Tracking

    Science.gov (United States)

    Liss, J.; Dunagan, S. E.; Johnson, R. R.; Chang, C. S.; LeBlanc, S. E.; Shinozuka, Y.; Redemann, J.; Flynn, C. J.; Segal-Rosenhaimer, M.; Pistone, K.; Kacenelenbogen, M. S.; Fahey, L.

    2016-12-01

    High Precision Sunphotometer using Wide Dynamic Range (WDR) Camera TrackingThe NASA Ames Sun-photometer-Satellite Group, DOE, PNNL Atmospheric Sciences and Global Change Division, and NASA Goddard's AERONET (AErosol RObotic NETwork) team recently collaborated on the development of a new airborne sunphotometry instrument that provides information on gases and aerosols extending far beyond what can be derived from discrete-channel direct-beam measurements, while preserving or enhancing many of the desirable AATS features (e.g., compactness, versatility, automation, reliability). The enhanced instrument combines the sun-tracking ability of the current 14-Channel NASA Ames AATS-14 with the sky-scanning ability of the ground-based AERONET Sun/sky photometers, while extending both AATS-14 and AERONET capabilities by providing full spectral information from the UV (350 nm) to the SWIR (1,700 nm). Strengths of this measurement approach include many more wavelengths (isolated from gas absorption features) that may be used to characterize aerosols and detailed (oversampled) measurements of the absorption features of specific gas constituents. The Sky Scanning Sun Tracking Airborne Radiometer (3STAR) replicates the radiometer functionality of the AATS-14 instrument but incorporates modern COTS technologies for all instruments subsystems. A 19-channel radiometer bundle design is borrowed from a commercial water column radiance instrument manufactured by Biospherical Instruments of San Diego California (ref, Morrow and Hooker)) and developed using NASA funds under the Small Business Innovative Research (SBIR) program. The 3STAR design also incorporates the latest in robotic motor technology embodied in Rotary actuators from Oriental motor Corp. having better than 15 arc seconds of positioning accuracy. Control system was designed, tested and simulated using a Hybrid-Dynamical modeling methodology. The design also replaces the classic quadrant detector tracking sensor with a

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  7. Image dynamic range test and evaluation of Gaofen-2 dual cameras

    Science.gov (United States)

    Zhang, Zhenhua; Gan, Fuping; Wei, Dandan

    2015-12-01

    In order to fully understand the dynamic range of Gaofen-2 satellite data and support the data processing, application and next satellites development, in this article, we evaluated the dynamic range by calculating some statistics such as maximum ,minimum, average and stand deviation of four images obtained at the same time by Gaofen-2 dual cameras in Beijing area; then the maximum ,minimum, average and stand deviation of each longitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of each camera's dynamic range consistency; and these four statistics of each latitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of the dynamic range consistency between PMS1 and PMS2 at last. The results suggest that there is a wide dynamic range of DN value in the image obtained by PMS1 and PMS2 which contains rich information of ground objects; in general, the consistency of dynamic range between the single camera images is in close agreement, but also a little difference, so do the dual cameras. The consistency of dynamic range between the single camera images is better than the dual cameras'.

  8. Multi-exposure high dynamic range image synthesis with camera shake correction

    Science.gov (United States)

    Li, Xudong; Chen, Yongfu; Jiang, Hongzhi; Zhao, Huijie

    2017-10-01

    Machine vision plays an important part in industrial online inspection. Owing to the nonuniform illuminance conditions and variable working distances, the captured image tends to be over-exposed or under-exposed. As a result, when processing the image such as crack inspection, the algorithm complexity and computing time increase. Multiexposure high dynamic range (HDR) image synthesis is used to improve the quality of the captured image, whose dynamic range is limited. Inevitably, camera shake will result in ghost effect, which blurs the synthesis image to some extent. However, existed exposure fusion algorithms assume that the input images are either perfectly aligned or captured in the same scene. These assumptions limit the application. At present, widely used registration based on Scale Invariant Feature Transform (SIFT) is usually time consuming. In order to rapidly obtain a high quality HDR image without ghost effect, we come up with an efficient Low Dynamic Range (LDR) images capturing approach and propose a registration method based on ORiented Brief (ORB) and histogram equalization which can eliminate the illumination differences between the LDR images. The fusion is performed after alignment. The experiment results demonstrate that the proposed method is robust to illumination changes and local geometric distortion. Comparing with other exposure fusion methods, our method is more efficient and can produce HDR images without ghost effect by registering and fusing four multi-exposure images.

  9. High dynamic range adaptive real-time smart camera: an overview of the HDR-ARTiST project

    Science.gov (United States)

    Lapray, Pierre-Jean; Heyrman, Barthélémy; Ginhac, Dominique

    2015-04-01

    Standard cameras capture only a fraction of the information that is visible to the human visual system. This is specifically true for natural scenes including areas of low and high illumination due to transitions between sunlit and shaded areas. When capturing such a scene, many cameras are unable to store the full Dynamic Range (DR) resulting in low quality video where details are concealed in shadows or washed out by sunlight. The imaging technique that can overcome this problem is called HDR (High Dynamic Range) imaging. This paper describes a complete smart camera built around a standard off-the-shelf LDR (Low Dynamic Range) sensor and a Virtex-6 FPGA board. This smart camera called HDR-ARtiSt (High Dynamic Range Adaptive Real-time Smart camera) is able to produce a real-time HDR live video color stream by recording and combining multiple acquisitions of the same scene while varying the exposure time. This technique appears as one of the most appropriate and cheapest solution to enhance the dynamic range of real-life environments. HDR-ARtiSt embeds real-time multiple captures, HDR processing, data display and transfer of a HDR color video for a full sensor resolution (1280 1024 pixels) at 60 frames per second. The main contributions of this work are: (1) Multiple Exposure Control (MEC) dedicated to the smart image capture with alternating three exposure times that are dynamically evaluated from frame to frame, (2) Multi-streaming Memory Management Unit (MMMU) dedicated to the memory read/write operations of the three parallel video streams, corresponding to the different exposure times, (3) HRD creating by combining the video streams using a specific hardware version of the Devebecs technique, and (4) Global Tone Mapping (GTM) of the HDR scene for display on a standard LCD monitor.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

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

    International Nuclear Information System (INIS)

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

    1990-01-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-07-01

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

  14. Comparative evaluation of consumer grade cameras and mobile phone cameras for close range photogrammetry

    Science.gov (United States)

    Chikatsu, Hirofumi; Takahashi, Yoji

    2009-08-01

    The authors have been concentrating on developing convenient 3D measurement methods using consumer grade digital cameras, and it was concluded that consumer grade digital cameras are expected to become a useful photogrammetric device for the various close range application fields. On the other hand, mobile phone cameras which have 10 mega pixels were appeared on the market in Japan. In these circumstances, we are faced with alternative epoch-making problem whether mobile phone cameras are able to take the place of consumer grade digital cameras in close range photogrammetric applications. In order to evaluate potentials of mobile phone cameras in close range photogrammetry, comparative evaluation between mobile phone cameras and consumer grade digital cameras are investigated in this paper with respect to lens distortion, reliability, stability and robustness. The calibration tests for 16 mobile phone cameras and 50 consumer grade digital cameras were conducted indoors using test target. Furthermore, practability of mobile phone camera for close range photogrammetry was evaluated outdoors. This paper presents that mobile phone cameras have ability to take the place of consumer grade digital cameras, and develop the market in digital photogrammetric fields.

  15. Dynamic imaging with coincidence gamma camera

    International Nuclear Information System (INIS)

    Elhmassi, Ahmed

    2008-01-01

    In this paper we develop a technique to calculate dynamic parameters from data acquired using gamma-camera PET (gc PET). Our method is based on an algorithm development for dynamic SPECT, which processes all decency projection data simultaneously instead of reconstructing a series of static images individually. The algorithm was modified to account for the extra data that is obtained with gc PET (compared with SPEC). The method was tested using simulated projection data for both a SPECT and a gc PET geometry. These studies showed the ability of the code to reconstruct simulated data with a varying range of half-lives. The accuracy of the algorithm was measured in terms of the reconstructed half-life and initial activity for the simulated object. The reconstruction of gc PET data showed improvement in half-life and activity compared to SPECT data of 23% and 20%, respectively (at 50 iterations). The gc PET algorithm was also tested using data from an experimental phantom and finally, applied to a clinical dataset, where the algorithm was further modified to deal with the situation where the activity in certain pixels decreases and then increases during the acquisition. (author)

  16. High Dynamic Range Imaging Using Multiple Exposures

    Science.gov (United States)

    Hou, Xinglin; Luo, Haibo; Zhou, Peipei; Zhou, Wei

    2017-06-01

    It is challenging to capture a high-dynamic range (HDR) scene using a low-dynamic range (LDR) camera. This paper presents an approach for improving the dynamic range of cameras by using multiple exposure images of same scene taken under different exposure times. First, the camera response function (CRF) is recovered by solving a high-order polynomial in which only the ratios of the exposures are used. Then, the HDR radiance image is reconstructed by weighted summation of the each radiance maps. After that, a novel local tone mapping (TM) operator is proposed for the display of the HDR radiance image. By solving the high-order polynomial, the CRF can be recovered quickly and easily. Taken the local image feature and characteristic of histogram statics into consideration, the proposed TM operator could preserve the local details efficiently. Experimental result demonstrates the effectiveness of our method. By comparison, the method outperforms other methods in terms of imaging quality.

  17. Dynamic gamma camera scintigraphy in primary hypoovarism

    International Nuclear Information System (INIS)

    Peshev, N.; Mladenov, B.; Topalov, I.; Tsanev, Ts.

    1988-01-01

    Twenty-seven patients with primary hypoovarism and 10 controls were examined. After intravenous injection of 111 to 175 MBq 99m Tc pertechnetate, dynamic gamma camera scintigraphy for 15 minutes was carried out. In the patients with primary amenorrhea no functioning ovarial tissue was visualized or the ovaries were diminished in size, strongly reduced and non-homogenous accumulation of the radionuclide with unclear and uneven delineation were observed. In the patients with primary infertility, the gamma camera investigation gave information not only about the presence of ovarial parenchyma, but about the extent of the inflammatory process, too. In the patients after surgical intervention, the dynamic radioisotope investigation gave information about the volume and the site of the surgical intervention, as well as about the conditions of the residual parenchyma

  18. High Dynamic Range Video

    CERN Document Server

    Myszkowski, Karol

    2008-01-01

    This book presents a complete pipeline forHDR image and video processing fromacquisition, through compression and quality evaluation, to display. At the HDR image and video acquisition stage specialized HDR sensors or multi-exposure techniques suitable for traditional cameras are discussed. Then, we present a practical solution for pixel values calibration in terms of photometric or radiometric quantities, which are required in some technically oriented applications. Also, we cover the problem of efficient image and video compression and encoding either for storage or transmission purposes, in

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

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

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

  20. High dynamic range imaging sensors and architectures

    CERN Document Server

    Darmont, Arnaud

    2013-01-01

    Illumination is a crucial element in many applications, matching the luminance of the scene with the operational range of a camera. When luminance cannot be adequately controlled, a high dynamic range (HDR) imaging system may be necessary. These systems are being increasingly used in automotive on-board systems, road traffic monitoring, and other industrial, security, and military applications. This book provides readers with an intermediate discussion of HDR image sensors and techniques for industrial and non-industrial applications. It describes various sensor and pixel architectures capable

  1. Microprocessor-controlled wide-range streak camera

    Science.gov (United States)

    Lewis, Amy E.; Hollabaugh, Craig

    2006-08-01

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

  2. Microprocessor-controlled, wide-range streak camera

    International Nuclear Information System (INIS)

    Amy E. Lewis; Craig Hollabaugh

    2006-01-01

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

  3. Microprocessor-controlled, wide-range streak camera

    Energy Technology Data Exchange (ETDEWEB)

    Amy E. Lewis, Craig Hollabaugh

    2006-09-01

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

  4. Real-Time Hand Posture Recognition Using a Range Camera

    Science.gov (United States)

    Lahamy, Herve

    The basic goal of human computer interaction is to improve the interaction between users and computers by making computers more usable and receptive to the user's needs. Within this context, the use of hand postures in replacement of traditional devices such as keyboards, mice and joysticks is being explored by many researchers. The goal is to interpret human postures via mathematical algorithms. Hand posture recognition has gained popularity in recent years, and could become the future tool for humans to interact with computers or virtual environments. An exhaustive description of the frequently used methods available in literature for hand posture recognition is provided. It focuses on the different types of sensors and data used, the segmentation and tracking methods, the features used to represent the hand postures as well as the classifiers considered in the recognition process. Those methods are usually presented as highly robust with a recognition rate close to 100%. However, a couple of critical points necessary for a successful real-time hand posture recognition system require major improvement. Those points include the features used to represent the hand segment, the number of postures simultaneously recognizable, the invariance of the features with respect to rotation, translation and scale and also the behavior of the classifiers against non-perfect hand segments for example segments including part of the arm or missing part of the palm. A 3D time-of-flight camera named SR4000 has been chosen to develop a new methodology because of its capability to provide in real-time and at high frame rate 3D information on the scene imaged. This sensor has been described and evaluated for its capability for capturing in real-time a moving hand. A new recognition method that uses the 3D information provided by the range camera to recognize hand postures has been proposed. The different steps of this methodology including the segmentation, the tracking, the hand

  5. Nonlinear dynamic range transformation in visual communication channels.

    Science.gov (United States)

    Alter-Gartenberg, R

    1996-01-01

    The article evaluates nonlinear dynamic range transformation in the context of the end-to-end continuous-input/discrete processing/continuous-display imaging process. Dynamic range transformation is required when we have the following: (i) the wide dynamic range encountered in nature is compressed into the relatively narrow dynamic range of the display, particularly for spatially varying irradiance (e.g., shadow); (ii) coarse quantization is expanded to the wider dynamic range of the display; and (iii) nonlinear tone scale transformation compensates for the correction in the camera amplifier.

  6. What about getting physiological information into dynamic gamma camera studies

    International Nuclear Information System (INIS)

    Kiuru, A.; Nickles, R. J.; Holden, J. E.; Polcyn, R. E.

    1976-01-01

    A general technique has been developed for the multiplexing of time dependent analog signals into the individual frames of a gamma camera dynamic function study. A pulse train, frequency-modulated by the physiological signal, is capacitively coupled to the preamplifier servicing anyone of the outer phototubes of the camera head. These negative tail pulses imitate photoevents occuring at a point outside of the camera field of view, chosen to occupy a data cell in an unused corner of the computer-stored square image. By defining a region of interest around this cell, the resulting time-activity curve displays the physiological variable in temporal synchrony with the radiotracer distribution. (author)

  7. High-dynamic-range imaging for cloud segmentation

    Science.gov (United States)

    Dev, Soumyabrata; Savoy, Florian M.; Lee, Yee Hui; Winkler, Stefan

    2018-04-01

    Sky-cloud images obtained from ground-based sky cameras are usually captured using a fisheye lens with a wide field of view. However, the sky exhibits a large dynamic range in terms of luminance, more than a conventional camera can capture. It is thus difficult to capture the details of an entire scene with a regular camera in a single shot. In most cases, the circumsolar region is overexposed, and the regions near the horizon are underexposed. This renders cloud segmentation for such images difficult. In this paper, we propose HDRCloudSeg - an effective method for cloud segmentation using high-dynamic-range (HDR) imaging based on multi-exposure fusion. We describe the HDR image generation process and release a new database to the community for benchmarking. Our proposed approach is the first using HDR radiance maps for cloud segmentation and achieves very good results.

  8. Dynamic Planar Range Maxima Queries

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Tsakalidis, Konstantinos

    2011-01-01

    We consider the dynamic two-dimensional maxima query problem. Let P be a set of n points in the plane. A point is maximal if it is not dominated by any other point in P. We describe two data structures that support the reporting of the t maximal points that dominate a given query point, and allow...... for insertions and deletions of points in P. In the pointer machine model we present a linear space data structure with O(logn + t) worst case query time and O(logn) worst case update time. This is the first dynamic data structure for the planar maxima dominance query problem that achieves these bounds...... are integers in the range U = {0, …,2 w  − 1 }. We present a linear space data structure that supports 3-sided range maxima queries in O(logn/loglogn+t) worst case time and updates in O(logn/loglogn) worst case time. These are the first sublogarithmic worst case bounds for all operations in the RAM model....

  9. On the accuracy potential of focused plenoptic camera range determination in long distance operation

    Science.gov (United States)

    Sardemann, Hannes; Maas, Hans-Gerd

    2016-04-01

    Plenoptic cameras have found increasing interest in optical 3D measurement techniques in recent years. While their basic principle is 100 years old, the development in digital photography, micro-lens fabrication technology and computer hardware has boosted the development and lead to several commercially available ready-to-use cameras. Beyond their popular option of a posteriori image focusing or total focus image generation, their basic ability of generating 3D information from single camera imagery depicts a very beneficial option for certain applications. The paper will first present some fundamentals on the design and history of plenoptic cameras and will describe depth determination from plenoptic camera image data. It will then present an analysis of the depth determination accuracy potential of plenoptic cameras. While most research on plenoptic camera accuracy so far has focused on close range applications, we will focus on mid and long ranges of up to 100 m. This range is especially relevant, if plenoptic cameras are discussed as potential mono-sensorial range imaging devices in (semi-)autonomous cars or in mobile robotics. The results show the expected deterioration of depth measurement accuracy with depth. At depths of 30-100 m, which may be considered typical in autonomous driving, depth errors in the order of 3% (with peaks up to 10-13 m) were obtained from processing small point clusters on an imaged target. Outliers much higher than these values were observed in single point analysis, stressing the necessity of spatial or spatio-temporal filtering of the plenoptic camera depth measurements. Despite these obviously large errors, a plenoptic camera may nevertheless be considered a valid option for the application fields of real-time robotics like autonomous driving or unmanned aerial and underwater vehicles, where the accuracy requirements decrease with distance.

  10. RADIANCE DOMAIN COMPOSITING FOR HIGH DYNAMIC RANGE IMAGING

    Directory of Open Access Journals (Sweden)

    M.R. Renu

    2013-02-01

    Full Text Available High dynamic range imaging aims at creating an image with a range of intensity variations larger than the range supported by a camera sensor. Most commonly used methods combine multiple exposure low dynamic range (LDR images, to obtain the high dynamic range (HDR image. Available methods typically neglect the noise term while finding appropriate weighting functions to estimate the camera response function as well as the radiance map. We look at the HDR imaging problem in a denoising frame work and aim at reconstructing a low noise radiance map from noisy low dynamic range images, which is tone mapped to get the LDR equivalent of the HDR image. We propose a maximum aposteriori probability (MAP based reconstruction of the HDR image using Gibb’s prior to model the radiance map, with total variation (TV as the prior to avoid unnecessary smoothing of the radiance field. To make the computation with TV prior efficient, we extend the majorize-minimize method of upper bounding the total variation by a quadratic function to our case which has a nonlinear term arising from the camera response function. A theoretical justification for doing radiance domain denoising as opposed to image domain denoising is also provided.

  11. Practical target location and accuracy indicator in digital close range photogrammetry using consumer grade cameras

    Science.gov (United States)

    Moriya, Gentaro; Chikatsu, Hirofumi

    2011-07-01

    Recently, pixel numbers and functions of consumer grade digital camera are amazingly increasing by modern semiconductor and digital technology, and there are many low-priced consumer grade digital cameras which have more than 10 mega pixels on the market in Japan. In these circumstances, digital photogrammetry using consumer grade cameras is enormously expected in various application fields. There is a large body of literature on calibration of consumer grade digital cameras and circular target location. Target location with subpixel accuracy had been investigated as a star tracker issue, and many target location algorithms have been carried out. It is widely accepted that the least squares models with ellipse fitting is the most accurate algorithm. However, there are still problems for efficient digital close range photogrammetry. These problems are reconfirmation of the target location algorithms with subpixel accuracy for consumer grade digital cameras, relationship between number of edge points along target boundary and accuracy, and an indicator for estimating the accuracy of normal digital close range photogrammetry using consumer grade cameras. With this motive, an empirical testing of several algorithms for target location with subpixel accuracy and an indicator for estimating the accuracy are investigated in this paper using real data which were acquired indoors using 7 consumer grade digital cameras which have 7.2 mega pixels to 14.7 mega pixels.

  12. Enhancing swimming pool safety by the use of range-imaging cameras

    Science.gov (United States)

    Geerardyn, D.; Boulanger, S.; Kuijk, M.

    2015-05-01

    Drowning is the cause of death of 372.000 people, each year worldwide, according to the report of November 2014 of the World Health Organization.1 Currently, most swimming pools only use lifeguards to detect drowning people. In some modern swimming pools, camera-based detection systems are nowadays being integrated. However, these systems have to be mounted underwater, mostly as a replacement of the underwater lighting. In contrast, we are interested in range imaging cameras mounted on the ceiling of the swimming pool, allowing to distinguish swimmers at the surface from drowning people underwater, while keeping the large field-of-view and minimizing occlusions. However, we have to take into account that the water surface of a swimming pool is not a flat, but mostly rippled surface, and that the water is transparent for visible light, but less transparent for infrared or ultraviolet light. We investigated the use of different types of 3D cameras to detect objects underwater at different depths and with different amplitudes of surface perturbations. Specifically, we performed measurements with a commercial Time-of-Flight camera, a commercial structured-light depth camera and our own Time-of-Flight system. Our own system uses pulsed Time-of-Flight and emits light of 785 nm. The measured distances between the camera and the object are influenced through the perturbations on the water surface. Due to the timing of our Time-of-Flight camera, our system is theoretically able to minimize the influence of the reflections of a partially-reflecting surface. The combination of a post image-acquisition filter compensating for the perturbations and the use of a light source with shorter wavelengths to enlarge the depth range can improve the current commercial cameras. As a result, we can conclude that low-cost range imagers can increase swimming pool safety, by inserting a post-processing filter and the use of another light source.

  13. Dynamic Human Body Modeling Using a Single RGB Camera.

    Science.gov (United States)

    Zhu, Haiyu; Yu, Yao; Zhou, Yu; Du, Sidan

    2016-03-18

    In this paper, we present a novel automatic pipeline to build personalized parametric models of dynamic people using a single RGB camera. Compared to previous approaches that use monocular RGB images, our system can model a 3D human body automatically and incrementally, taking advantage of human motion. Based on coarse 2D and 3D poses estimated from image sequences, we first perform a kinematic classification of human body parts to refine the poses and obtain reconstructed body parts. Next, a personalized parametric human model is generated by driving a general template to fit the body parts and calculating the non-rigid deformation. Experimental results show that our shape estimation method achieves comparable accuracy with reconstructed models using depth cameras, yet requires neither user interaction nor any dedicated devices, leading to the feasibility of using this method on widely available smart phones.

  14. Dynamic range majority data structures

    DEFF Research Database (Denmark)

    Elmasry, Amr Ahmed Abd Elmoneim; He, Meng; Munro, J. Ian

    2011-01-01

    Given a set P of n coloured points on the real line, we study the problem of answering range α-majority (or "heavy hitter") queries on P. More specifically, for a query range Q, we want to return each colour that is assigned to more than an α-fraction of the points contained in Q. We present a ne...

  15. Understanding synthesis imaging dynamic range

    Science.gov (United States)

    Braun, R.

    2013-03-01

    We develop a general framework for quantifying the many different contributions to the noise budget of an image made with an array of dishes or aperture array stations. Each noise contribution to the visibility data is associated with a relevant correlation timescale and frequency bandwidth so that the net impact on a complete observation can be assessed when a particular effect is not captured in the instrumental calibration. All quantities are parameterised as function of observing frequency and the visibility baseline length. We apply the resulting noise budget analysis to a wide range of existing and planned telescope systems that will operate between about 100 MHz and 5 GHz to ascertain the magnitude of the calibration challenges that they must overcome to achieve thermal noise limited performance. We conclude that calibration challenges are increased in several respects by small dimensions of the dishes or aperture array stations. It will be more challenging to achieve thermal noise limited performance using 15 m class dishes rather than the 25 m dishes of current arrays. Some of the performance risks are mitigated by the deployment of phased array feeds and more with the choice of an (alt,az,pol) mount, although a larger dish diameter offers the best prospects for risk mitigation. Many improvements to imaging performance can be anticipated at the expense of greater complexity in calibration algorithms. However, a fundamental limitation is ultimately imposed by an insufficient number of data constraints relative to calibration variables. The upcoming aperture array systems will be operating in a regime that has never previously been addressed, where a wide range of effects are expected to exceed the thermal noise by two to three orders of magnitude. Achieving routine thermal noise limited imaging performance with these systems presents an extreme challenge. The magnitude of that challenge is inversely related to the aperture array station diameter.

  16. Detection of mixed-range proton pencil beams with a prompt gamma slit camera

    International Nuclear Information System (INIS)

    Priegnitz, M; Helmbrecht, S; Fiedler, F; Janssens, G; Smeets, J; Vander Stappen, F; Perali, I; Sterpin, E

    2016-01-01

    With increasing availability of proton and particle therapy centers for tumor treatment, the need for in vivo range verification methods comes more into the focus. Imaging of prompt gamma rays emitted during the treatment is one of the possibilities currently under investigation. A knife-edge shaped slit camera was recently proposed for this task and measurements proved the feasibility of range deviation detection in homogeneous and inhomogeneous targets. In the present paper, we concentrate on laterally inhomogeneous materials, which lead to range mixing situations when crossed by one pencil beam: different sections of the beam have different ranges. We chose exemplative cases from clinical irradiation and assembled idealized tissue equivalent targets. One-dimensional emission profiles were obtained by measuring the prompt gamma emission with the slit camera. It could be shown that the resulting range deviations can be detected by evaluation of the measured data with a previously developed range deviation detection algorithm. The retrieved value, however, strongly depends on the target composition, and is not necessarily in direct relation to the ranges of both parts of the beam. By combining the range deviation detection with an analysis of the slope of the distal edge of the measured prompt gamma profile, the origin of the detected range deviation, i.e. the mixed range of the beam, is also identified. It could be demonstrated that range mixed prompt gamma profiles exhibit less steep distal slopes than profiles from beams traversing laterally homogeneous material. For future application of the slit camera to patient irradiation with double scattered proton beams, situations similar to the range mixing cases are present and results could possibly apply. (paper)

  17. Application of phase matching autofocus in airborne long-range oblique photography camera

    Science.gov (United States)

    Petrushevsky, Vladimir; Guberman, Asaf

    2014-06-01

    The Condor2 long-range oblique photography (LOROP) camera is mounted in an aerodynamically shaped pod carried by a fast jet aircraft. Large aperture, dual-band (EO/MWIR) camera is equipped with TDI focal plane arrays and provides high-resolution imagery of extended areas at long stand-off ranges, at day and night. Front Ritchey-Chretien optics is made of highly stable materials. However, the camera temperature varies considerably in flight conditions. Moreover, a composite-material structure of the reflective objective undergoes gradual dehumidification in dry nitrogen atmosphere inside the pod, causing some small decrease of the structure length. The temperature and humidity effects change a distance between the mirrors by just a few microns. The distance change is small but nevertheless it alters the camera's infinity focus setpoint significantly, especially in the EO band. To realize the optics' resolution potential, the optimal focus shall be constantly maintained. In-flight best focus calibration and temperature-based open-loop focus control give mostly satisfactory performance. To get even better focusing precision, a closed-loop phase-matching autofocus method was developed for the camera. The method makes use of an existing beamsharer prism FPA arrangement where aperture partition exists inherently in an area of overlap between the adjacent detectors. The defocus is proportional to an image phase shift in the area of overlap. Low-pass filtering of raw defocus estimate reduces random errors related to variable scene content. Closed-loop control converges robustly to precise focus position. The algorithm uses the temperature- and range-based focus prediction as an initial guess for the closed-loop phase-matching control. The autofocus algorithm achieves excellent results and works robustly in various conditions of scene illumination and contrast.

  18. Evaluation of Real-Time Hand Motion Tracking Using a Range Camera and the Mean-Shift Algorithm

    Science.gov (United States)

    Lahamy, H.; Lichti, D.

    2011-09-01

    Several sensors have been tested for improving the interaction between humans and machines including traditional web cameras, special gloves, haptic devices, cameras providing stereo pairs of images and range cameras. Meanwhile, several methods are described in the literature for tracking hand motion: the Kalman filter, the mean-shift algorithm and the condensation algorithm. In this research, the combination of a range camera and the simple version of the mean-shift algorithm has been evaluated for its capability for hand motion tracking. The evaluation was assessed in terms of position accuracy of the tracking trajectory in x, y and z directions in the camera space and the time difference between image acquisition and image display. Three parameters have been analyzed regarding their influence on the tracking process: the speed of the hand movement, the distance between the camera and the hand and finally the integration time of the camera. Prior to the evaluation, the required warm-up time of the camera has been measured. This study has demonstrated the suitability of the range camera used in combination with the mean-shift algorithm for real-time hand motion tracking but for very high speed hand movement in the traverse plane with respect to the camera, the tracking accuracy is low and requires improvement.

  19. SINGLE IMAGE CAMERA CALIBRATION IN CLOSE RANGE PHOTOGRAMMETRY FOR SOLDER JOINT ANALYSIS

    Directory of Open Access Journals (Sweden)

    D. Heinemann

    2016-06-01

    Full Text Available Printed Circuit Boards (PCB play an important role in the manufacturing of electronic devices. To ensure a correct function of the PCBs a certain amount of solder paste is needed during the placement of components. The aim of the current research is to develop an real-time, closed-loop solution for the analysis of the printing process where solder is printed onto PCBs. Close range photogrammetry allows for determination of the solder volume and a subsequent correction if necessary. Photogrammetry is an image based method for three dimensional reconstruction from two dimensional image data of an object. A precise camera calibration is indispensable for an accurate reconstruction. In our certain application it is not possible to use calibration methods with two dimensional calibration targets. Therefore a special calibration target was developed and manufactured, which allows for single image camera calibration.

  20. Development of a Compton camera for online ion beam range verification via prompt γ detection

    Energy Technology Data Exchange (ETDEWEB)

    Aldawood, S. [LMU Munich, Garching (Germany); King Saud University, Riyadh (Saudi Arabia); Liprandi, S.; Marinsek, T.; Bortfeldt, J.; Lang, C.; Lutter, R.; Dedes, G.; Parodi, K.; Thirolf, P.G. [LMU Munich, Garching (Germany); Maier, L.; Gernhaeuser, R. [TU Munich, Garching (Germany); Kolff, H. van der [LMU Munich, Garching (Germany); TU Delft (Netherlands); Castelhano, I. [LMU Munich, Garching (Germany); University of Lisbon, Lisbon (Portugal); Schaart, D.R. [TU Delft (Netherlands)

    2015-07-01

    Precise and preferably online ion beam range verification is a mandatory prerequisite to fully exploit the advantages of hadron therapy in cancer treatment. An imaging system is being developed in Garching aiming to detect promptγ rays induced by nuclear reactions between the ion beam and biological tissue. The Compton camera prototype consists of a stack of six customized double-sided Si-strip detectors (DSSSD, 50 x 50 mm{sup 2}, 0.5 mm thick, 128 strips/side) acting as scatterer, while the absorber is formed by a monolithic LaBr{sub 3}:Ce scintillator crystal (50 x 50 x 30 mm{sup 3}) read out by a position-sensitive multi-anode photomultiplier (Hamamatsu H9500). The on going characterization of the Compton camera properties and its individual components both offline in the laboratory as well as online using proton beam are presented.

  1. Range camera on conveyor belts: estimating size distribution and systematic errors due to occlusion

    Science.gov (United States)

    Blomquist, Mats; Wernersson, Ake V.

    1999-11-01

    When range cameras are used for analyzing irregular material on a conveyor belt there will be complications like missing segments caused by occlusion. Also, a number of range discontinuities will be present. In a frame work towards stochastic geometry, conditions are found for the cases when range discontinuities take place. The test objects in this paper are pellets for the steel industry. An illuminating laser plane will give range discontinuities at the edges of each individual object. These discontinuities are used to detect and measure the chord created by the intersection of the laser plane and the object. From the measured chords we derive the average diameter and its variance. An improved method is to use a pair of parallel illuminating light planes to extract two chords. The estimation error for this method is not larger than the natural shape fluctuations (the difference in diameter) for the pellets. The laser- camera optronics is sensitive enough both for material on a conveyor belt and free falling material leaving the conveyor.

  2. Procedure for fully automatic orientation of camera in digital close-range photogrammetry

    Science.gov (United States)

    Huang, Yong Ru; Trinder, John C.

    1994-03-01

    This paper presents an automatic procedure of camera orientation developed for a digital close-range photogrammetric system. In this application, small bright balls mounted on a calibration frame serve as control points, since their shape in an image is invariant to the camera position and they are always imaged as circles. To recognize the circles in the image, an edge detection algorithm is exploited to extract the circular edges with subpixel accuracy. The circles are recognized by matching the shape of these edges with the shape of an ideal circular target. The central location of the circles and their diameters can be determined from these edge points. The determination of the identification of the circles is a problem of artificial intelligence. The list of the circles in the image must be arranged in the order of the balls in 3D world. A fast search is described that is based on exploiting the available information in order to limit the number of possible alternative orders of the targets. In this way, the search can be achieved efficiently. The identification of circles results in the correct numbers being attached to the corresponding circles. Finally, the precise camera parameters are calculated by bundle adjustment.

  3. Dynamic Artificial Potential Fields for Autonomous Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Jhala, Arnav Harish

    2009-01-01

    the implementation and evaluation of Artificial Potential Fields for automatic camera placement. We first describe the re- casting of the frame composition problem as a solution to a two particles suspended in an Artificial Potential Field. We demonstrate the application of this technique to control both camera...

  4. HEVC for high dynamic range services

    Science.gov (United States)

    Kim, Seung-Hwan; Zhao, Jie; Misra, Kiran; Segall, Andrew

    2015-09-01

    Displays capable of showing a greater range of luminance values can render content containing high dynamic range information in a way such that the viewers have a more immersive experience. This paper introduces the design aspects of a high dynamic range (HDR) system, and examines the performance of the HDR processing chain in terms of compression efficiency. Specifically it examines the relation between recently introduced Society of Motion Picture and Television Engineers (SMPTE) ST 2084 transfer function and the High Efficiency Video Coding (HEVC) standard. SMPTE ST 2084 is designed to cover the full range of an HDR signal from 0 to 10,000 nits, however in many situations the valid signal range of actual video might be smaller than SMPTE ST 2084 supported range. The above restricted signal range results in restricted range of code values for input video data and adversely impacts compression efficiency. In this paper, we propose a code value remapping method that extends the restricted range code values into the full range code values so that the existing standards such as HEVC may better compress the video content. The paper also identifies related non-normative encoder-only changes that are required for remapping method for a fair comparison with anchor. Results are presented comparing the efficiency of the current approach versus the proposed remapping method for HM-16.2.

  5. High dynamic range coding imaging system

    Science.gov (United States)

    Wu, Renfan; Huang, Yifan; Hou, Guangqi

    2014-10-01

    We present a high dynamic range (HDR) imaging system design scheme based on coded aperture technique. This scheme can help us obtain HDR images which have extended depth of field. We adopt Sparse coding algorithm to design coded patterns. Then we utilize the sensor unit to acquire coded images under different exposure settings. With the guide of the multiple exposure parameters, a series of low dynamic range (LDR) coded images are reconstructed. We use some existing algorithms to fuse and display a HDR image by those LDR images. We build an optical simulation model and get some simulation images to verify the novel system.

  6. Dynamic range meter for radiofrequency amplifiers

    Directory of Open Access Journals (Sweden)

    Drozd S. S.

    2009-04-01

    Full Text Available The new measurement setup having increased on 20…30 dB the own dynamic range in comparison with the standard circuit of the dynamic range meter is offered and the rated value of an error bringing by setup in the worst case does not exceed ± 2,8 dB. The measurement setup can be applied also to determinate levels of intermodulation components average power amplifiers and powerful amplifiers of a low-frequency at replacement of the quartz filter on meeting low-frequency the LC-filter and the spectrum analyzer.

  7. Video-rate or high-precision: a flexible range imaging camera

    Science.gov (United States)

    Dorrington, Adrian A.; Cree, Michael J.; Carnegie, Dale A.; Payne, Andrew D.; Conroy, Richard M.; Godbaz, John P.; Jongenelen, Adrian P. P.

    2008-02-01

    A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications. Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system's frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution. In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection.

  8. Multi-person tracking with overlapping cameras in complex, dynamic environments

    NARCIS (Netherlands)

    Liem, M.; Gavrila, D.M.

    2009-01-01

    This paper presents a multi-camera system to track multiple persons in complex, dynamic environments. Position measurements are obtained by carving out the space defined by foreground regions in the overlapping camera views and projecting these onto blobs on the ground plane. Person appearance is

  9. Scintillator-CCD camera system light output response to dosimetry parameters for proton beam range measurement

    Energy Technology Data Exchange (ETDEWEB)

    Daftari, Inder K., E-mail: idaftari@radonc.ucsf.edu [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States); Castaneda, Carlos M.; Essert, Timothy [Crocker Nuclear Laboratory,1 Shields Avenue, University of California-Davis, Davis, CA 95616 (United States); Phillips, Theodore L.; Mishra, Kavita K. [Department of Radiation Oncology, 1600 Divisadero Street, Suite H1031, University of California-San Francisco, San Francisco, CA 94143 (United States)

    2012-09-11

    The purpose of this study is to investigate the luminescence light output response in a plastic scintillator irradiated by a 67.5 MeV proton beam using various dosimetry parameters. The relationship of the visible scintillator light with the beam current or dose rate, aperture size and the thickness of water in the water-column was studied. The images captured on a CCD camera system were used to determine optimal dosimetry parameters for measuring the range of a clinical proton beam. The method was developed as a simple quality assurance tool to measure the range of the proton beam and compare it to (a) measurements using two segmented ionization chambers and water column between them, and (b) with an ionization chamber (IC-18) measurements in water. We used a block of plastic scintillator that measured 5 Multiplication-Sign 5 Multiplication-Sign 5 cm{sup 3} to record visible light generated by a 67.5 MeV proton beam. A high-definition digital video camera Moticam 2300 connected to a PC via USB 2.0 communication channel was used to record images of scintillation luminescence. The brightness of the visible light was measured while changing beam current and aperture size. The results were analyzed to obtain the range and were compared with the Bragg peak measurements with an ionization chamber. The luminescence light from the scintillator increased linearly with the increase of proton beam current. The light output also increased linearly with aperture size. The relationship between the proton range in the scintillator and the thickness of the water column showed good linearity with a precision of 0.33 mm (SD) in proton range measurement. For the 67.5 MeV proton beam utilized, the optimal parameters for scintillator light output response were found to be 15 nA (16 Gy/min) and an aperture size of 15 mm with image integration time of 100 ms. The Bragg peak depth brightness distribution was compared with the depth dose distribution from ionization chamber measurements

  10. Wide dynamic range beam profile monitor

    International Nuclear Information System (INIS)

    Lee, D.M.; Brown, D.; Hardekopf, R.; Bilskie, J.R.; van Dyck, O.B.V.

    1985-01-01

    An economical harp multiplexer system has been developed to achieve a wide dynamic range. The harp system incorporates a pneumatically actuated harp detector with ceramic boards and carbon wires; a high-sensitivity multiplexer packaged in a double-wide NIM module; and flat, shielded ribbon cable consisting of individual twisted pairs. The system multiplexes 30 wires in each of the x and y planes simultaneously and operates with or without computer control. The system has operated in beams of 100 nA to 1 mA, 1- to 120-Hz repetition rate, with a signal-to-noise ratio of greater than 10/1

  11. Mitochondrial uncouplers with an extraordinary dynamic range.

    Science.gov (United States)

    Lou, Phing-How; Hansen, Birgit S; Olsen, Preben H; Tullin, Søren; Murphy, Michael P; Brand, Martin D

    2007-10-01

    We have discovered that some weak uncouplers (typified by butylated hydroxytoluene) have a dynamic range of more than 10(6) in vitro: the concentration giving measurable uncoupling is less than one millionth of the concentration causing full uncoupling. They achieve this through a high-affinity interaction with the mitochondrial adenine nucleotide translocase that causes significant but limited uncoupling at extremely low uncoupler concentrations, together with more conventional uncoupling at much higher concentrations. Uncoupling at the translocase is not by a conventional weak acid/anion cycling mechanism since it is also caused by substituted triphenylphosphonium molecules, which are not anionic and cannot protonate. Covalent attachment of the uncoupler to a mitochondrially targeted hydrophobic cation sensitizes it to membrane potential, giving a small additional effect. The wide dynamic range of these uncouplers in isolated mitochondria and intact cells reveals a novel allosteric activation of proton transport through the adenine nucleotide translocase and provides a promising starting point for designing safer uncouplers for obesity therapy.

  12. 3D MODELLING BY LOW-COST RANGE CAMERA: SOFTWARE EVALUATION AND COMPARISON

    Directory of Open Access Journals (Sweden)

    R. Ravanelli

    2017-11-01

    Full Text Available The aim of this work is to present a comparison among three software applications currently available for the Occipital Structure SensorTM; all these software were developed for collecting 3D models of objects easily and in real-time with this structured light range camera. The SKANECT, itSeez3D and Scanner applications were thus tested: a DUPLOTM bricks construction was scanned with the three applications and the obtained models were compared to the model virtually generated with a standard CAD software, which served as reference. The results demonstrate that all the software applications are generally characterized by the same level of geometric accuracy, which amounts to very few millimetres. However, the itSeez3D software, which requires a payment of $7 to export each model, represents surely the best solution, both from the point of view of the geometric accuracy and, mostly, at the level of the color restitution. On the other hand, Scanner, which is a free software, presents an accuracy comparable to that of itSeez3D. At the same time, though, the colors are often smoothed and not perfectly overlapped to the corresponding part of the model. Lastly, SKANECT is the software that generates the highest number of points, but it has also some issues with the rendering of the colors.

  13. HiRes camera and LIDAR ranging system for the Clementine mission

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G.; Kordas, J.F.; Lewis, I.T. [and others

    1995-04-01

    Lawrence Livermore National Laboratory developed a space-qualified High Resolution (HiRes) imaging LIDAR (Light Detection And Ranging) system for use on the DoD Clementine mission. The Clementine mission provided more than 1.7 million images of the moon, earth, and stars, including the first ever complete systematic surface mapping of the moon from the ultra-violet to near-infrared spectral regions. This article describes the Clementine HiRes/LIDAR system, discusses design goals and preliminary estimates of on-orbit performance, and summarizes lessons learned in building and using the sensor. The LIDAR receiver system consists of a High Resolution (HiRes) imaging channel which incorporates an intensified multi-spectral visible camera combined with a Laser ranging channel which uses an avalanche photo-diode for laser pulse detection and timing. The receiver was bore sighted to a light-weight McDonnell-Douglas diode-pumped ND:YAG laser transmitter that emmitted 1.06 {micro}m wavelength pulses of 200 mJ/pulse and 10 ns pulse-width, The LIDAR receiver uses a common F/9.5 Cassegrain telescope assembly. The optical path of the telescope is split using a color-separating beamsplitter. The imaging channel incorporates a filter wheel assembly which spectrally selects the light which is imaged onto a custom 12 mm gated image intensifier fiber-optically-coupled into a 384 x 276 pixel frame transfer CCD FPA. The image intensifier was spectrally sensitive over the 0.4 to 0.8 {micro}m wavelength region. The six-position filter wheel contained 4 narrow spectral filters, one broadband and one blocking filter. At periselene (400 km) the HiRes/LIDAR imaged a 2.8 km swath width at 20-meter resolution. The LIDAR function detected differential signal return with a 40-meter range accuracy, with a maximum range capability of 640 km, limited by the bit counter in the range return counting clock.

  14. Real-Time Range Sensing Video Camera for Human/Robot Interfacing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In comparison to stereovision, it is well known that structured-light illumination has distinct advantages including the use of only one camera, being significantly...

  15. Transmission dynamic range in chest radiology

    International Nuclear Information System (INIS)

    Lemmers, H.E.A.S.J.; Schultze Kool, L.J.; van Elburg, H.J.; Boelens, F.

    1989-01-01

    Due to the large difference in transmission between the lung area and the mediastinum, the human chest is a challenging object for radiographic imaging. This study is performed in order to define the dynamic range needed for a chest imaging chain. Eight hundred seventy-five consecutive outpatients were imaged with a prototype AMBER (advanced multiple beam equalization radiography) unit at 141 kVp. The equalization facility was disabled, allowing for the simultaneous capture of a film image and a digital dataset representing the local patient transmission in fields of approximately 2x2 cm. The datasets were analyzed to obtain the relation between the average transmission distribution in a subset of the population and physical parameters characterizing this subset, such as body weight or length

  16. Video Enhancement and Dynamic Range Control of HDR Sequences for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Giovanni Ramponi

    2007-01-01

    Full Text Available CMOS video cameras with high dynamic range (HDR output are particularly suitable for driving assistance applications, where lighting conditions can strongly vary, going from direct sunlight to dark areas in tunnels. However, common visualization devices can only handle a low dynamic range, and thus a dynamic range reduction is needed. Many algorithms have been proposed in the literature to reduce the dynamic range of still pictures. Anyway, extending the available methods to video is not straightforward, due to the peculiar nature of video data. We propose an algorithm for both reducing the dynamic range of video sequences and enhancing its appearance, thus improving visual quality and reducing temporal artifacts. We also provide an optimized version of our algorithm for a viable hardware implementation on an FPGA. The feasibility of this implementation is demonstrated by means of a case study.

  17. Photonic limiters with enhanced dynamic range

    Science.gov (United States)

    Kononchuk, Rodion; Limberopoulos, Nicholaos; Anisimov, Igor; Vitebskiy, Ilya; Chabanov, Andrey

    2018-02-01

    Optical limiters transmit low intensity input light while blocking input light with the intensity exceeding certain limiting threshold. Conventional passive limiters utilize nonlinear optical materials, which are transparent at low light intensity and turn absorptive at high intensity. Strong nonlinear absorption, though, can result in over- heating and destruction of the limiter. Another problem is that the limiting threshold provided by the available optical material with nonlinear absorption is too high for many applications. To address the above problems, the nonlinear material can be incorporated in a photonic structure with engineered dispersion. At low intensity, the photonic structure can display resonant transmission via localized mode(s), while at high intensity the resonant transmission can disappear, and the entire stack can become highly re ective (not absorptive) within a broad frequency range. In the proposed design, the transition from the resonant transmission at low intensity to nearly total re ectivity at high intensity does not rely on nonlinear absorption; instead, it requires only a modest change in the refractive index of the nonlinear material. The latter implies a dramatic increase in the dynamic range of the limiter. The main idea is to eliminate the high-intensity resonant transmission by decoupling the localized (resonant) modes from the input light, rather than suppressing those modes using nonlinear absorption. Similar approach can be used for light modulation and switching.

  18. SU-F-J-206: Systematic Evaluation of the Minimum Detectable Shift Using a Range- Finding Camera

    Energy Technology Data Exchange (ETDEWEB)

    Platt, M; Platt, M [College of Medicine University of Cincinnati, Cincinnati, OH (United States); Lamba, M [University of Cincinnati, Cincinnati, OH (United States); Mascia, A [University of Cincinnati Medical Center, Cincinnati, OH (United States); Huang, K [UC Health Barret Cancer Center, Cincinnati, OH (United States)

    2016-06-15

    Purpose: The robotic table used for patient alignment in proton therapy is calibrated only at commissioning under well-defined conditions and table shifts may vary over time and with differing conditions. The purpose of this study is to systematically investigate minimum detectable shifts using a time-of-flight (TOF) range-finding camera for table position feedback. Methods: A TOF camera was used to acquire one hundred 424 × 512 range images from a flat surface before and after known shifts. Range was assigned by averaging central regions of the image across multiple images. Depth resolution was determined by evaluating the difference between the actual shift of the surface and the measured shift. Depth resolution was evaluated for number of images averaged, area of sensor over which depth was averaged, distance from camera to surface, central versus peripheral image regions, and angle of surface relative to camera. Results: For one to one thousand images with a shift of one millimeter the range in error was 0.852 ± 0.27 mm to 0.004 ± 0.01 mm (95% C.I.). For varying regions of the camera sensor the range in error was 0.02 ± 0.05 mm to 0.47 ± 0.04 mm. The following results are for 10 image averages. For areas ranging from one pixel to 9 × 9 pixels the range in error was 0.15 ± 0.09 to 0.29 ± 0.15 mm (1σ). For distances ranging from two to four meters the range in error was 0.15 ± 0.09 to 0.28 ± 0.15 mm. For an angle of incidence between thirty degrees and ninety degrees the average range in error was 0.11 ± 0.08 to 0.17 ± 0.09 mm. Conclusion: It is feasible to use a TOF camera for measuring shifts in flat surfaces under clinically relevant conditions with submillimeter precision.

  19. A three-step vehicle detection framework for range estimation using a single camera

    CSIR Research Space (South Africa)

    Kanjee, R

    2015-12-01

    Full Text Available This paper proposes and validates a real-time onroad vehicle detection system, which uses a single camera for the purpose of intelligent driver assistance. A three-step vehicle detection framework is presented to detect and track the target vehicle...

  20. a Tool for Crowdsourced Building Information Modeling Through Low-Cost Range Camera: Preliminary Demonstration and Potential

    Science.gov (United States)

    Capocchiano, F.; Ravanelli, R.; Crespi, M.

    2017-11-01

    Within the construction sector, Building Information Models (BIMs) are more and more used thanks to the several benefits that they offer in the design of new buildings and the management of the existing ones. Frequently, however, BIMs are not available for already built constructions, but, at the same time, the range camera technology provides nowadays a cheap, intuitive and effective tool for automatically collecting the 3D geometry of indoor environments. It is thus essential to find new strategies, able to perform the first step of the scan to BIM process, by extracting the geometrical information contained in the 3D models that are so easily collected through the range cameras. In this work, a new algorithm to extract planimetries from the 3D models of rooms acquired by means of a range camera is therefore presented. The algorithm was tested on two rooms, characterized by different shapes and dimensions, whose 3D models were captured with the Occipital Structure SensorTM. The preliminary results are promising: the developed algorithm is able to model effectively the 2D shape of the investigated rooms, with an accuracy level comprised in the range of 5 - 10 cm. It can be potentially used by non-expert users in the first step of the BIM generation, when the building geometry is reconstructed, for collecting crowdsourced indoor information in the frame of BIMs Volunteered Geographic Information (VGI) generation.

  1. Technical Note: Range verification system using edge detection method for a scintillator and a CCD camera system

    Energy Technology Data Exchange (ETDEWEB)

    Saotome, Naoya, E-mail: naosao@nirs.go.jp; Furukawa, Takuji; Hara, Yousuke; Mizushima, Kota; Tansho, Ryohei; Saraya, Yuichi; Shirai, Toshiyuki; Noda, Koji [Department of Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2016-04-15

    Purpose: Three-dimensional irradiation with a scanned carbon-ion beam has been performed from 2011 at the authors’ facility. The authors have developed the rotating-gantry equipped with the scanning irradiation system. The number of combinations of beam properties to measure for the commissioning is more than 7200, i.e., 201 energy steps, 3 intensities, and 12 gantry angles. To compress the commissioning time, quick and simple range verification system is required. In this work, the authors develop a quick range verification system using scintillator and charge-coupled device (CCD) camera and estimate the accuracy of the range verification. Methods: A cylindrical plastic scintillator block and a CCD camera were installed on the black box. The optical spatial resolution of the system is 0.2 mm/pixel. The camera control system was connected and communicates with the measurement system that is part of the scanning system. The range was determined by image processing. Reference range for each energy beam was determined by a difference of Gaussian (DOG) method and the 80% of distal dose of the depth-dose distribution that were measured by a large parallel-plate ionization chamber. The authors compared a threshold method and a DOG method. Results: The authors found that the edge detection method (i.e., the DOG method) is best for the range detection. The accuracy of range detection using this system is within 0.2 mm, and the reproducibility of the same energy measurement is within 0.1 mm without setup error. Conclusions: The results of this study demonstrate that the authors’ range check system is capable of quick and easy range verification with sufficient accuracy.

  2. Technical Note: Range verification system using edge detection method for a scintillator and a CCD camera system

    International Nuclear Information System (INIS)

    Saotome, Naoya; Furukawa, Takuji; Hara, Yousuke; Mizushima, Kota; Tansho, Ryohei; Saraya, Yuichi; Shirai, Toshiyuki; Noda, Koji

    2016-01-01

    Purpose: Three-dimensional irradiation with a scanned carbon-ion beam has been performed from 2011 at the authors’ facility. The authors have developed the rotating-gantry equipped with the scanning irradiation system. The number of combinations of beam properties to measure for the commissioning is more than 7200, i.e., 201 energy steps, 3 intensities, and 12 gantry angles. To compress the commissioning time, quick and simple range verification system is required. In this work, the authors develop a quick range verification system using scintillator and charge-coupled device (CCD) camera and estimate the accuracy of the range verification. Methods: A cylindrical plastic scintillator block and a CCD camera were installed on the black box. The optical spatial resolution of the system is 0.2 mm/pixel. The camera control system was connected and communicates with the measurement system that is part of the scanning system. The range was determined by image processing. Reference range for each energy beam was determined by a difference of Gaussian (DOG) method and the 80% of distal dose of the depth-dose distribution that were measured by a large parallel-plate ionization chamber. The authors compared a threshold method and a DOG method. Results: The authors found that the edge detection method (i.e., the DOG method) is best for the range detection. The accuracy of range detection using this system is within 0.2 mm, and the reproducibility of the same energy measurement is within 0.1 mm without setup error. Conclusions: The results of this study demonstrate that the authors’ range check system is capable of quick and easy range verification with sufficient accuracy.

  3. Quantitative high dynamic range beam profiling for fluorescence microscopy

    International Nuclear Information System (INIS)

    Mitchell, T. J.; Saunter, C. D.; O’Nions, W.; Girkin, J. M.; Love, G. D.

    2014-01-01

    Modern developmental biology relies on optically sectioning fluorescence microscope techniques to produce non-destructive in vivo images of developing specimens at high resolution in three dimensions. As optimal performance of these techniques is reliant on the three-dimensional (3D) intensity profile of the illumination employed, the ability to directly record and analyze these profiles is of great use to the fluorescence microscopist or instrument builder. Though excitation beam profiles can be measured indirectly using a sample of fluorescent beads and recording the emission along the microscope detection path, we demonstrate an alternative approach where a miniature camera sensor is used directly within the illumination beam. Measurements taken using our approach are solely concerned with the illumination optics as the detection optics are not involved. We present a miniature beam profiling device and high dynamic range flux reconstruction algorithm that together are capable of accurately reproducing quantitative 3D flux maps over a large focal volume. Performance of this beam profiling system is verified within an optical test bench and demonstrated for fluorescence microscopy by profiling the low NA illumination beam of a single plane illumination microscope. The generality and success of this approach showcases a widely flexible beam amplitude diagnostic tool for use within the life sciences

  4. Achieving sub-millimetre precision with a solid-state full-field heterodyning range imaging camera

    Science.gov (United States)

    Dorrington, A. A.; Cree, M. J.; Payne, A. D.; Conroy, R. M.; Carnegie, D. A.

    2007-09-01

    We have developed a full-field solid-state range imaging system capable of capturing range and intensity data simultaneously for every pixel in a scene with sub-millimetre range precision. The system is based on indirect time-of-flight measurements by heterodyning intensity-modulated illumination with a gain modulation intensified digital video camera. Sub-millimetre precision to beyond 5 m and 2 mm precision out to 12 m has been achieved. In this paper, we describe the new sub-millimetre class range imaging system in detail, and review the important aspects that have been instrumental in achieving high precision ranging. We also present the results of performance characterization experiments and a method of resolving the range ambiguity problem associated with homodyne and heterodyne ranging systems.

  5. Pose and Shape Reconstruction of a Noncooperative Spacecraft Using Camera and Range Measurements

    Directory of Open Access Journals (Sweden)

    Renato Volpe

    2017-01-01

    Full Text Available Recent interest in on-orbit proximity operations has pushed towards the development of autonomous GNC strategies. In this sense, optical navigation enables a wide variety of possibilities as it can provide information not only about the kinematic state but also about the shape of the observed object. Various mission architectures have been either tested in space or studied on Earth. The present study deals with on-orbit relative pose and shape estimation with the use of a monocular camera and a distance sensor. The goal is to develop a filter which estimates an observed satellite’s relative position, velocity, attitude, and angular velocity, along with its shape, with the measurements obtained by a camera and a distance sensor mounted on board a chaser which is on a relative trajectory around the target. The filter’s efficiency is proved with a simulation on a virtual target object. The results of the simulation, even though relevant to a simplified scenario, show that the estimation process is successful and can be considered a promising strategy for a correct and safe docking maneuver.

  6. Stereo Vision-Based High Dynamic Range Imaging Using Differently-Exposed Image Pair

    Directory of Open Access Journals (Sweden)

    Won-Jae Park

    2017-06-01

    Full Text Available In this paper, a high dynamic range (HDR imaging method based on the stereo vision system is presented. The proposed method uses differently exposed low dynamic range (LDR images captured from a stereo camera. The stereo LDR images are first converted to initial stereo HDR images using the inverse camera response function estimated from the LDR images. However, due to the limited dynamic range of the stereo LDR camera, the radiance values in under/over-exposed regions of the initial main-view (MV HDR image can be lost. To restore these radiance values, the proposed stereo matching and hole-filling algorithms are applied to the stereo HDR images. Specifically, the auxiliary-view (AV HDR image is warped by using the estimated disparity between initial the stereo HDR images and then effective hole-filling is applied to the warped AV HDR image. To reconstruct the final MV HDR, the warped and hole-filled AV HDR image is fused with the initial MV HDR image using the weight map. The experimental results demonstrate objectively and subjectively that the proposed stereo HDR imaging method provides better performance compared to the conventional method.

  7. Single camera analyses in studying pattern forming dynamics of player interactions in team sports.

    OpenAIRE

    Duarte, Ricardo; Fernandes, Orlando; Folgado, Hugo; Araújo, Duarte

    2013-01-01

    A network of patterned interactions between players characterises team ball sports. Thus, interpersonal coordination patterns are an important topic in the study of performance in such sports. A very useful method has been the study of inter-individual interactions captured by a single camera filming an extended performance area. The appropriate collection of positional data allows investigating the pattern forming dynamics emerging in different performance sub-phases of team ball sports. Thi...

  8. Modulation of neuronal dynamic range using two different adaptation mechanisms

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2017-01-01

    Full Text Available The capability of neurons to discriminate between intensity of external stimulus is measured by its dynamic range. A larger dynamic range indicates a greater probability of neuronal survival. In this study, the potential roles of adaptation mechanisms (ion currents in modulating neuronal dynamic range were numerically investigated. Based on the adaptive exponential integrate-and-fire model, which includes two different adaptation mechanisms, i.e. subthreshold and suprathreshold (spike-triggered adaptation, our results reveal that the two adaptation mechanisms exhibit rather different roles in regulating neuronal dynamic range. Specifically, subthreshold adaptation acts as a negative factor that observably decreases the neuronal dynamic range, while suprathreshold adaptation has little influence on the neuronal dynamic range. Moreover, when stochastic noise was introduced into the adaptation mechanisms, the dynamic range was apparently enhanced, regardless of what state the neuron was in, e.g. adaptive or non-adaptive. Our model results suggested that the neuronal dynamic range can be differentially modulated by different adaptation mechanisms. Additionally, noise was a non-ignorable factor, which could effectively modulate the neuronal dynamic range.

  9. Logarithmic circuit with wide dynamic range

    Science.gov (United States)

    Wiley, P. H.; Manus, E. A. (Inventor)

    1978-01-01

    A circuit deriving an output voltage that is proportional to the logarithm of a dc input voltage susceptible to wide variations in amplitude includes a constant current source which forward biases a diode so that the diode operates in the exponential portion of its voltage versus current characteristic, above its saturation current. The constant current source includes first and second, cascaded feedback, dc operational amplifiers connected in negative feedback circuit. An input terminal of the first amplifier is responsive to the input voltage. A circuit shunting the first amplifier output terminal includes a resistor in series with the diode. The voltage across the resistor is sensed at the input of the second dc operational feedback amplifier. The current flowing through the resistor is proportional to the input voltage over the wide range of variations in amplitude of the input voltage.

  10. Camera pose estimation for augmented reality in a small indoor dynamic scene

    Science.gov (United States)

    Frikha, Rawia; Ejbali, Ridha; Zaied, Mourad

    2017-09-01

    Camera pose estimation remains a challenging task for augmented reality (AR) applications. Simultaneous localization and mapping (SLAM)-based methods are able to estimate the six degrees of freedom camera motion while constructing a map of an unknown environment. However, these methods do not provide any reference for where to insert virtual objects since they do not have any information about scene structure and may fail in cases of occlusion of three-dimensional (3-D) map points or dynamic objects. This paper presents a real-time monocular piece wise planar SLAM method using the planar scene assumption. Using planar structures in the mapping process allows rendering virtual objects in a meaningful way on the one hand and improving the precision of the camera pose and the quality of 3-D reconstruction of the environment by adding constraints on 3-D points and poses in the optimization process on the other hand. We proposed to benefit from the 3-D planes rigidity motion in the tracking process to enhance the system robustness in the case of dynamic scenes. Experimental results show that using a constrained planar scene improves our system accuracy and robustness compared with the classical SLAM systems.

  11. Unattended real-time re-establishment of visibility in high dynamic range video and stills

    Science.gov (United States)

    Abidi, B.

    2014-05-01

    We describe a portable unattended persistent surveillance system that corrects for harsh illumination conditions, where bright sun light creates mixed contrast effects, i.e., heavy shadows and washouts. These effects result in high dynamic range scenes, where illuminance can vary from few luxes to a 6 figure value. When using regular monitors and cameras, such wide span of illuminations can only be visualized if the actual range of values is compressed, leading to the creation of saturated and/or dark noisy areas and a loss of information in these areas. Images containing extreme mixed contrast cannot be fully enhanced from a single exposure, simply because all information is not present in the original data. The active intervention in the acquisition process is required. A software package, capable of integrating multiple types of COTS and custom cameras, ranging from Unmanned Aerial Systems (UAS) data links to digital single-lens reflex cameras (DSLR), is described. Hardware and software are integrated via a novel smart data acquisition algorithm, which communicates to the camera the parameters that would maximize information content in the final processed scene. A fusion mechanism is then applied to the smartly acquired data, resulting in an enhanced scene where information in both dark and bright areas is revealed. Multi-threading and parallel processing are exploited to produce automatic real time full motion corrected video. A novel enhancement algorithm was also devised to process data from legacy and non-controllable cameras. The software accepts and processes pre-recorded sequences and stills, enhances visible, night vision, and Infrared data, and successfully applies to night time and dark scenes. Various user options are available, integrating custom functionalities of the application into intuitive and easy to use graphical interfaces. The ensuing increase in visibility in surveillance video and intelligence imagery will expand the performance and

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

    International Nuclear Information System (INIS)

    Attwood, D.T.

    1976-01-01

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

  13. The analysis on dynamic range of industrial CT system

    International Nuclear Information System (INIS)

    Wang Huiqian; Wang Jue; Tan Hui

    2011-01-01

    Concerning the limitations of the definition of the dynamic range of industrial computed tomography (ICT) system, it researches the definition, measuring method and influencing factors of the dynamic range of industrial computed tomography (ICT) system from the concept of quantization and system. First, the character of the input-output curve was analyzed, and the method of obtaining the dynamic range of industrial computed tomography (ICT) system was proposed. Then, an experiment model was designed to gain dynamic range, based on 6 MeV high-energy industrial computed tomography (ICT) system. The results show that the larger the photosurface is, the smaller the dynamic range is, when the other parameters are unchanged. (authors)

  14. A comparison of two prompt gamma imaging techniques with collimator-based cameras for range verification in proton therapy

    Science.gov (United States)

    Lin, Hsin-Hon; Chang, Hao-Ting; Chao, Tsi-Chian; Chuang, Keh-Shih

    2017-08-01

    In vivo range verification plays an important role in proton therapy to fully utilize the benefits of the Bragg peak (BP) for delivering high radiation dose to tumor, while sparing the normal tissue. For accurately locating the position of BP, camera equipped with collimators (multi-slit and knife-edge collimator) to image prompt gamma (PG) emitted along the proton tracks in the patient have been proposed for range verification. The aim of the work is to compare the performance of multi-slit collimator and knife-edge collimator for non-invasive proton beam range verification. PG imaging was simulated by a validated GATE/GEANT4 Monte Carlo code to model the spot-scanning proton therapy and cylindrical PMMA phantom in detail. For each spot, 108 protons were simulated. To investigate the correlation between the acquired PG profile and the proton range, the falloff regions of PG profiles were fitted with a 3-line-segment curve function as the range estimate. Factors including the energy window setting, proton energy, phantom size, and phantom shift that may influence the accuracy of detecting range were studied. Results indicated that both collimator systems achieve reasonable accuracy and good response to the phantom shift. The accuracy of range predicted by multi-slit collimator system is less affected by the proton energy, while knife-edge collimator system can achieve higher detection efficiency that lead to a smaller deviation in predicting range. We conclude that both collimator systems have potentials for accurately range monitoring in proton therapy. It is noted that neutron contamination has a marked impact on range prediction of the two systems, especially in multi-slit system. Therefore, a neutron reduction technique for improving the accuracy of range verification of proton therapy is needed.

  15. Improved measurement linearity and precision for AMCW time-of-flight range imaging cameras.

    Science.gov (United States)

    Payne, Andrew D; Dorrington, Adrian A; Cree, Michael J; Carnegie, Dale A

    2010-08-10

    Time-of-flight range imaging systems utilizing the amplitude modulated continuous wave (AMCW) technique often suffer from measurement nonlinearity due to the presence of aliased harmonics within the amplitude modulation signals. Typically a calibration is performed to correct these errors. We demonstrate an alternative phase encoding approach that attenuates the harmonics during the sampling process, thereby improving measurement linearity in the raw measurements. This mitigates the need to measure the system's response or calibrate for environmental changes. In conjunction with improved linearity, we demonstrate that measurement precision can also be increased by reducing the duty cycle of the amplitude modulated illumination source (while maintaining overall illumination power).

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

    International Nuclear Information System (INIS)

    Remy, Sophie

    1991-01-01

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

  17. On Dynamic Range Limitations of CMOS Current Conveyors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1999-01-01

    frequency band and for the situation where the conveyor is used over the full bandwidth achievable. Finally, the optimisation of the current input range is related to the distortion characteristics and it is pointed out that to a first order approximation the distortion is independent of the current range.......This paper is concerned with the dynamic range of continuous time CMOS current mode circuits. As a representative current mode device a class AB current conveyor is examined. First, the voltage input range of the high impedance Y input is investigated. Next, the current input range of the low...... impedance X input is investigated. It is compared to the thermal noise in the X to Z signal path in order to evaluate the dynamic range, and the dependencies of the dynamic range on the supply voltage and the transistor lay-out is derived, both for the situation where the conveyor is used over a narrow...

  18. Survey of potential use of dynamic line phantom for quality control of Gamma camera

    International Nuclear Information System (INIS)

    Trindev, P.; Ozturk, N.

    2004-01-01

    Different phantoms, used to evaluate the essential for image quality parameters of gamma cameras in order to avoid artefacts, are presented. The prices are significant and it is a sensible approach to optimise the type and number of phantoms necessary for quality control. Among all phantoms the price of 'Dynamic Line Phantom' (DLP) is impressive, but it is announced to substitute several 'passive' and 'active' phantoms. The goal of this paper is to justify this statement. The programs, based on image profile are discussed in the paper and the practical uses of the different programs are given

  19. Development of Measurement Device of Working Radius of Crane Based on Single CCD Camera and Laser Range Finder

    Science.gov (United States)

    Nara, Shunsuke; Takahashi, Satoru

    In this paper, what we want to do is to develop an observation device to measure the working radius of a crane truck. The device has a single CCD camera, a laser range finder and two AC servo motors. First, in order to measure the working radius, we need to consider algorithm of a crane hook recognition. Then, we attach the cross mark on the crane hook. Namely, instead of the crane hook, we try to recognize the cross mark. Further, for the observation device, we construct PI control system with an extended Kalman filter to track the moving cross mark. Through experiments, we show the usefulness of our device including new control system of mark tracking.

  20. Automatically assessing properties of dynamic cameras for camera selection and rapid deployment of video content analysis tasks in large-scale ad-hoc networks

    Science.gov (United States)

    den Hollander, Richard J. M.; Bouma, Henri; van Rest, Jeroen H. C.; ten Hove, Johan-Martijn; ter Haar, Frank B.; Burghouts, Gertjan J.

    2017-10-01

    Video analytics is essential for managing large quantities of raw data that are produced by video surveillance systems (VSS) for the prevention, repression and investigation of crime and terrorism. Analytics is highly sensitive to changes in the scene, and for changes in the optical chain so a VSS with analytics needs careful configuration and prompt maintenance to avoid false alarms. However, there is a trend from static VSS consisting of fixed CCTV cameras towards more dynamic VSS deployments over public/private multi-organization networks, consisting of a wider variety of visual sensors, including pan-tilt-zoom (PTZ) cameras, body-worn cameras and cameras on moving platforms. This trend will lead to more dynamic scenes and more frequent changes in the optical chain, creating structural problems for analytics. If these problems are not adequately addressed, analytics will not be able to continue to meet end users' developing needs. In this paper, we present a three-part solution for managing the performance of complex analytics deployments. The first part is a register containing meta data describing relevant properties of the optical chain, such as intrinsic and extrinsic calibration, and parameters of the scene such as lighting conditions or measures for scene complexity (e.g. number of people). A second part frequently assesses these parameters in the deployed VSS, stores changes in the register, and signals relevant changes in the setup to the VSS administrator. A third part uses the information in the register to dynamically configure analytics tasks based on VSS operator input. In order to support the feasibility of this solution, we give an overview of related state-of-the-art technologies for autocalibration (self-calibration), scene recognition and lighting estimation in relation to person detection. The presented solution allows for rapid and robust deployment of Video Content Analysis (VCA) tasks in large scale ad-hoc networks.

  1. Reconstructing Interlaced High-Dynamic-Range Video Using Joint Learning.

    Science.gov (United States)

    Inchang Choi; Seung-Hwan Baek; Kim, Min H

    2017-11-01

    For extending the dynamic range of video, it is a common practice to capture multiple frames sequentially with different exposures and combine them to extend the dynamic range of each video frame. However, this approach results in typical ghosting artifacts due to fast and complex motion in nature. As an alternative, video imaging with interlaced exposures has been introduced to extend the dynamic range. However, the interlaced approach has been hindered by jaggy artifacts and sensor noise, leading to concerns over image quality. In this paper, we propose a data-driven approach for jointly solving two specific problems of deinterlacing and denoising that arise in interlaced video imaging with different exposures. First, we solve the deinterlacing problem using joint dictionary learning via sparse coding. Since partial information of detail in differently exposed rows is often available via interlacing, we make use of the information to reconstruct details of the extended dynamic range from the interlaced video input. Second, we jointly solve the denoising problem by tailoring sparse coding to better handle additive noise in low-/high-exposure rows, and also adopt multiscale homography flow to temporal sequences for denoising. We anticipate that the proposed method will allow for concurrent capture of higher dynamic range video frames without suffering from ghosting artifacts. We demonstrate the advantages of our interlaced video imaging compared with the state-of-the-art high-dynamic-range video methods.

  2. Dynamic imaging with a triggered and intensified CCD camera system in a high-intensity neutron beam

    International Nuclear Information System (INIS)

    Vontobel, P.; Frei, G.; Brunner, J.; Gildemeister, A.E.; Engelhardt, M.

    2005-01-01

    When time-dependent processes within metallic structures should be inspected and visualized, neutrons are well suited due to their high penetration through Al, Ag, Ti or even steel. Then it becomes possible to inspect the propagation, distribution and evaporation of organic liquids as lubricants, fuel or water. The principle set-up of a suited real-time system was implemented and tested at the radiography facility NEUTRA of PSI. The highest beam intensity there is 2x10 7 cm -2 s -1 , which enables to observe sequences in a reasonable time and quality. The heart of the detection system is the MCP intensified CCD camera PI-Max with a Peltier cooled chip (1300x1340 pixels). The intensifier was used for both gating and image enhancement, where as the information was accumulated over many single frames on the chip before readout. Although, a 16-bit dynamic range is advertised by the camera manufacturers, it must be less due to the inherent noise level from the intensifier. The obtained result should be seen as the starting point to go ahead to fit the different requirements of car producers in respect to fuel injection, lubricant distribution, mechanical stability and operation control. Similar inspections will be possible for all devices with repetitive operation principle. Here, we report about two measurements dealing with the lubricant distribution in a running motorcycle motor turning at 1200rpm. We were monitoring the periodic stationary movements of piston, valves and camshaft with a micro-channel plate intensified CCD camera system (PI-Max 1300RB, Princeton Instruments) triggered at exactly chosen time points

  3. Projecting range-wide sun bear population trends using tree cover and camera-trap bycatch data.

    Directory of Open Access Journals (Sweden)

    Lorraine Scotson

    Full Text Available Monitoring population trends of threatened species requires standardized techniques that can be applied over broad areas and repeated through time. Sun bears Helarctos malayanus are a forest dependent tropical bear found throughout most of Southeast Asia. Previous estimates of global population trends have relied on expert opinion and cannot be systematically replicated. We combined data from 1,463 camera traps within 31 field sites across sun bear range to model the relationship between photo catch rates of sun bears and tree cover. Sun bears were detected in all levels of tree cover above 20%, and the probability of presence was positively associated with the amount of tree cover within a 6-km2 buffer of the camera traps. We used the relationship between catch rates and tree cover across space to infer temporal trends in sun bear abundance in response to tree cover loss at country and global-scales. Our model-based projections based on this "space for time" substitution suggested that sun bear population declines associated with tree cover loss between 2000-2014 in mainland southeast Asia were ~9%, with declines highest in Cambodia and lowest in Myanmar. During the same period, sun bear populations in insular southeast Asia (Malaysia, Indonesia and Brunei were projected to have declined at a much higher rate (22%. Cast forward over 30-years, from the year 2000, by assuming a constant rate of change in tree cover, we projected population declines in the insular region that surpassed 50%, meeting the IUCN criteria for endangered if sun bears were listed on the population level. Although this approach requires several assumptions, most notably that trends in abundance across space can be used to infer temporal trends, population projections using remotely sensed tree cover data may serve as a useful alternative (or supplement to expert opinion. The advantages of this approach is that it is objective, data-driven, repeatable, and it requires that

  4. Benchmarking novel approaches for modelling species range dynamics.

    Science.gov (United States)

    Zurell, Damaris; Thuiller, Wilfried; Pagel, Jörn; Cabral, Juliano S; Münkemüller, Tamara; Gravel, Dominique; Dullinger, Stefan; Normand, Signe; Schiffers, Katja H; Moore, Kara A; Zimmermann, Niklaus E

    2016-08-01

    Increasing biodiversity loss due to climate change is one of the most vital challenges of the 21st century. To anticipate and mitigate biodiversity loss, models are needed that reliably project species' range dynamics and extinction risks. Recently, several new approaches to model range dynamics have been developed to supplement correlative species distribution models (SDMs), but applications clearly lag behind model development. Indeed, no comparative analysis has been performed to evaluate their performance. Here, we build on process-based, simulated data for benchmarking five range (dynamic) models of varying complexity including classical SDMs, SDMs coupled with simple dispersal or more complex population dynamic models (SDM hybrids), and a hierarchical Bayesian process-based dynamic range model (DRM). We specifically test the effects of demographic and community processes on model predictive performance. Under current climate, DRMs performed best, although only marginally. Under climate change, predictive performance varied considerably, with no clear winners. Yet, all range dynamic models improved predictions under climate change substantially compared to purely correlative SDMs, and the population dynamic models also predicted reasonable extinction risks for most scenarios. When benchmarking data were simulated with more complex demographic and community processes, simple SDM hybrids including only dispersal often proved most reliable. Finally, we found that structural decisions during model building can have great impact on model accuracy, but prior system knowledge on important processes can reduce these uncertainties considerably. Our results reassure the clear merit in using dynamic approaches for modelling species' response to climate change but also emphasize several needs for further model and data improvement. We propose and discuss perspectives for improving range projections through combination of multiple models and for making these approaches

  5. Time course of dynamic range adaptation in the auditory nerve

    Science.gov (United States)

    Wang, Grace I.; Dean, Isabel; Delgutte, Bertrand

    2012-01-01

    Auditory adaptation to sound-level statistics occurs as early as in the auditory nerve (AN), the first stage of neural auditory processing. In addition to firing rate adaptation characterized by a rate decrement dependent on previous spike activity, AN fibers show dynamic range adaptation, which is characterized by a shift of the rate-level function or dynamic range toward the most frequently occurring levels in a dynamic stimulus, thereby improving the precision of coding of the most common sound levels (Wen B, Wang GI, Dean I, Delgutte B. J Neurosci 29: 13797–13808, 2009). We investigated the time course of dynamic range adaptation by recording from AN fibers with a stimulus in which the sound levels periodically switch from one nonuniform level distribution to another (Dean I, Robinson BL, Harper NS, McAlpine D. J Neurosci 28: 6430–6438, 2008). Dynamic range adaptation occurred rapidly, but its exact time course was difficult to determine directly from the data because of the concomitant firing rate adaptation. To characterize the time course of dynamic range adaptation without the confound of firing rate adaptation, we developed a phenomenological “dual adaptation” model that accounts for both forms of AN adaptation. When fitted to the data, the model predicts that dynamic range adaptation occurs as rapidly as firing rate adaptation, over 100–400 ms, and the time constants of the two forms of adaptation are correlated. These findings suggest that adaptive processing in the auditory periphery in response to changes in mean sound level occurs rapidly enough to have significant impact on the coding of natural sounds. PMID:22457465

  6. Automatic Generation of Wide Dynamic Range Image without Pseudo-Edge Using Integration of Multi-Steps Exposure Images

    Science.gov (United States)

    Migiyama, Go; Sugimura, Atsuhiko; Osa, Atsushi; Miike, Hidetoshi

    Recently, digital cameras are offering technical advantages rapidly. However, the shot image is different from the sight image generated when that scenery is seen with the naked eye. There are blown-out highlights and crushed blacks in the image that photographed the scenery of wide dynamic range. The problems are hardly generated in the sight image. These are contributory cause of difference between the shot image and the sight image. Blown-out highlights and crushed blacks are caused by the difference of dynamic range between the image sensor installed in a digital camera such as CCD and CMOS and the human visual system. Dynamic range of the shot image is narrower than dynamic range of the sight image. In order to solve the problem, we propose an automatic method to decide an effective exposure range in superposition of edges. We integrate multi-step exposure images using the method. In addition, we try to erase pseudo-edges using the process to blend exposure values. Afterwards, we get a pseudo wide dynamic range image automatically.

  7. Real-time high dynamic range laser scanning microscopy

    Science.gov (United States)

    Vinegoni, C.; Leon Swisher, C.; Fumene Feruglio, P.; Giedt, R. J.; Rousso, D. L.; Stapleton, S.; Weissleder, R.

    2016-04-01

    In conventional confocal/multiphoton fluorescence microscopy, images are typically acquired under ideal settings and after extensive optimization of parameters for a given structure or feature, often resulting in information loss from other image attributes. To overcome the problem of selective data display, we developed a new method that extends the imaging dynamic range in optical microscopy and improves the signal-to-noise ratio. Here we demonstrate how real-time and sequential high dynamic range microscopy facilitates automated three-dimensional neural segmentation. We address reconstruction and segmentation performance on samples with different size, anatomy and complexity. Finally, in vivo real-time high dynamic range imaging is also demonstrated, making the technique particularly relevant for longitudinal imaging in the presence of physiological motion and/or for quantification of in vivo fast tracer kinetics during functional imaging.

  8. Design of rotating mirror for ultra-high speed camera based on dynamic characteristic

    International Nuclear Information System (INIS)

    Li Chunbo; Chai Jinlong; Liang Yexing; Liu Chunping; Wang Hongzhi; Yu Chunhui; Li Jingzhen; Huang Hongbin

    2011-01-01

    A systematic design method has been proposed for studying the dynamic design of rotating mirror for ultra-high speed camera. With the finite element software, the numerical analyses of static, modal, harmonic responses and natural frequency sensitivity for the preliminary-designed rotating mirror were done based on the static and dynamic theories. Some experiments were done to verify the results. The physical dimensions of the rotating mirror were modified repeatedly according to the results for designing a new rotating mirror. Then simulation and experiments of fatigue life for the new rotating mirror under alternating force were done. The results show that the maximum static stress is less than the yield stress of the rotating mirror material, which proves the new rotating mirror will not be subjected to static strength failure. However, the results of modal and harmonic response analyses indicate that the dynamic characteristic of the new rotating mirror can not meet the design requirement for the first critical speed is less than the service speed. In all the physical dimensions of the rotating mirror, the circum radius of mirror body and natural frequency are negatively correlated and the degree of correlation is maximal. The first-order natural frequency in- creases from 459.4 Hz to 713.6 Hz, the rate of change is 55.3%, the first critical speed is up to 42 816 r/min, avoiding resonance successfully, and the fatigue strength of the new rotating mirror can meet the design requirement. (authors)

  9. Enhancement tuning and control for high dynamic range images in multi-scale locally adaptive contrast enhancement algorithms

    Science.gov (United States)

    Cvetkovic, Sascha D.; Schirris, Johan; de With, Peter H. N.

    2009-01-01

    For real-time imaging in surveillance applications, visibility of details is of primary importance to ensure customer confidence. If we display High Dynamic-Range (HDR) scenes whose contrast spans four or more orders of magnitude on a conventional monitor without additional processing, results are unacceptable. Compression of the dynamic range is therefore a compulsory part of any high-end video processing chain because standard monitors are inherently Low- Dynamic Range (LDR) devices with maximally two orders of display dynamic range. In real-time camera processing, many complex scenes are improved with local contrast enhancements, bringing details to the best possible visibility. In this paper, we show how a multi-scale high-frequency enhancement scheme, in which gain is a non-linear function of the detail energy, can be used for the dynamic range compression of HDR real-time video camera signals. We also show the connection of our enhancement scheme to the processing way of the Human Visual System (HVS). Our algorithm simultaneously controls perceived sharpness, ringing ("halo") artifacts (contrast) and noise, resulting in a good balance between visibility of details and non-disturbance of artifacts. The overall quality enhancement, suitable for both HDR and LDR scenes, is based on a careful selection of the filter types for the multi-band decomposition and a detailed analysis of the signal per frequency band.

  10. Evaluation of color encodings for high dynamic range pixels

    Science.gov (United States)

    Boitard, Ronan; Mantiuk, Rafal K.; Pouli, Tania

    2015-03-01

    Traditional Low Dynamic Range (LDR) color spaces encode a small fraction of the visible color gamut, which does not encompass the range of colors produced on upcoming High Dynamic Range (HDR) displays. Future imaging systems will require encoding much wider color gamut and luminance range. Such wide color gamut can be represented using floating point HDR pixel values but those are inefficient to encode. They also lack perceptual uniformity of the luminance and color distribution, which is provided (in approximation) by most LDR color spaces. Therefore, there is a need to devise an efficient, perceptually uniform and integer valued representation for high dynamic range pixel values. In this paper we evaluate several methods for encoding colour HDR pixel values, in particular for use in image and video compression. Unlike other studies we test both luminance and color difference encoding in a rigorous 4AFC threshold experiments to determine the minimum bit-depth required. Results show that the Perceptual Quantizer (PQ) encoding provides the best perceptual uniformity in the considered luminance range, however the gain in bit-depth is rather modest. More significant difference can be observed between color difference encoding schemes, from which YDuDv encoding seems to be the most efficient.

  11. Perceptual Effects of Dynamic Range Compression in Popular Music Recordings

    DEFF Research Database (Denmark)

    Hjortkjær, Jens; Walther-Hansen, Mads

    2014-01-01

    There is a widespread belief that the increasing use of dynamic range compression in music mastering (the loudnesswar) deteriorates sound quality but experimental evidence of perceptual effects is lacking. In this study, normal hearing listeners were asked to evaluate popular music recordings in ...

  12. Entanglement Growth in Quench Dynamics with Variable Range Interactions

    Directory of Open Access Journals (Sweden)

    J. Schachenmayer

    2013-09-01

    Full Text Available Studying entanglement growth in quantum dynamics provides both insight into the underlying microscopic processes and information about the complexity of the quantum states, which is related to the efficiency of simulations on classical computers. Recently, experiments with trapped ions, polar molecules, and Rydberg excitations have provided new opportunities to observe dynamics with long-range interactions. We explore nonequilibrium coherent dynamics after a quantum quench in such systems, identifying qualitatively different behavior as the exponent of algebraically decaying spin-spin interactions in a transverse Ising chain is varied. Computing the buildup of bipartite entanglement as well as mutual information between distant spins, we identify linear growth of entanglement entropy corresponding to propagation of quasiparticles for shorter-range interactions, with the maximum rate of growth occurring when the Hamiltonian parameters match those for the quantum phase transition. Counterintuitively, the growth of bipartite entanglement for long-range interactions is only logarithmic for most regimes, i.e., substantially slower than for shorter-range interactions. Experiments with trapped ions allow for the realization of this system with a tunable interaction range, and we show that the different phenomena are robust for finite system sizes and in the presence of noise. These results can act as a direct guide for the generation of large-scale entanglement in such experiments, towards a regime where the entanglement growth can render existing classical simulations inefficient.

  13. Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners

    Directory of Open Access Journals (Sweden)

    Martin Kirchberger

    2016-02-01

    Full Text Available Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings.

  14. Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners

    Science.gov (United States)

    Kirchberger, Martin

    2016-01-01

    Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings. PMID:26868955

  15. Dynamic Range Across Music Genres and the Perception of Dynamic Compression in Hearing-Impaired Listeners.

    Science.gov (United States)

    Kirchberger, Martin; Russo, Frank A

    2016-02-10

    Dynamic range compression serves different purposes in the music and hearing-aid industries. In the music industry, it is used to make music louder and more attractive to normal-hearing listeners. In the hearing-aid industry, it is used to map the variable dynamic range of acoustic signals to the reduced dynamic range of hearing-impaired listeners. Hence, hearing-aided listeners will typically receive a dual dose of compression when listening to recorded music. The present study involved an acoustic analysis of dynamic range across a cross section of recorded music as well as a perceptual study comparing the efficacy of different compression schemes. The acoustic analysis revealed that the dynamic range of samples from popular genres, such as rock or rap, was generally smaller than the dynamic range of samples from classical genres, such as opera and orchestra. By comparison, the dynamic range of speech, based on recordings of monologues in quiet, was larger than the dynamic range of all music genres tested. The perceptual study compared the effect of the prescription rule NAL-NL2 with a semicompressive and a linear scheme. Music subjected to linear processing had the highest ratings for dynamics and quality, followed by the semicompressive and the NAL-NL2 setting. These findings advise against NAL-NL2 as a prescription rule for recorded music and recommend linear settings. © The Author(s) 2016.

  16. Performance evaluation of a mouse-sized camera for dynamic studies in small animals

    International Nuclear Information System (INIS)

    Loudos, George; Majewski, Stan; Wojcik, Randy; Weisenberger, Andrew; Sakellios, Nicolas; Nikita, Konstantina; Uzunoglu, Nikolaos; Bouziotis, Penelope; Varvarigou, Alexandra

    2007-01-01

    A mouse sized camera has been built in terms of collaboration between the presenting institutions. The system is used for the performance of dynamic studies in small animals, in order to evaluate novel radiopharmaceuticals. The active area of the detector is approximately 48x96 mm allowing depiction of the entire mouse in a single view. The system is based on two flat-panel Hamamatsu H8500 position sensitive photomultiplier tubes (PSPMT), a pixellated NaI(Tl) scintillator and a copper-beryllium (CuBe) parallel-hole collimator. In this work, the evaluation results of the system are presented, using phantoms and small animals injected with conventional radiophrmaceuticals. Average resolution was ∼1.6 mm on the collimator surface and increased to ∼4.1 mm in 12 cm distance from the detector. The average energy resolution was measured and found to be ∼15.6% for Tc 99m . Results from imaging thin capillaries demonstrated system's high resolution and sensitivity in activity variations was shown. Initial dynamic studies have been carried out in small animals injected with Tc 99m -DTPA and Tc 99m -MDP. The results show system's ability to perform kinetic imaging in small animals

  17. Dynamical arrest in dense short-ranged attractive colloids

    International Nuclear Information System (INIS)

    Foffi, G; Sciortino, F; Zaccarelli, E; Tartaglia, P

    2004-01-01

    We study thermodynamic and dynamic properties of model colloidal systems interacting with a hard core repulsion and a short-range attraction, and provide an overall picture of their phase diagrams which shows a very rich phenomenology. We focus on the slow dynamic properties of this model, investigating in detail the glass transition lines (both repulsive and attractive), the glass-glass transitions and the location of the higher order singularities. We discuss the relative location of the glass lines and of the metastable liquid-gas binodal, an issue relevant for the understanding of low density arrested states of matter

  18. Extending the Dynamic Range of a Time Projection Chamber

    Science.gov (United States)

    Estee, Justin; S πRIT Collaboration

    2017-09-01

    The use of Time Projection Chambers (TPCs) in intermediate heavy ion reactions faces some challenges in addressing the energy losses that range from the small energy loss of relativistic pions to the large energy loss of slow moving heavy ions. A typical trade-off can be to set the smallest desired signals to be well within the lower limits of the dynamic range of the electronics while allowing for some larger signals to saturate the electronics. With wire plane anodes, signals from readout pads further away from the track remain unsaturated and allow signals from tracks with saturated pads to be accurately recovered. We illustrate this technique using data from the SAMURAI Pion-Reconstruction and Ion-Tracker (S πRIT) TPC , which recently measured pions and light charged particles in collisions of Sn+Sn isotopes. Our method exploits knowledge of how the induced charge distribution depends on the distance from the track to smoothly extend dynamic range even when some of the pads in the track are saturated. To accommodate the analysis of slow moving heavy ions, we have extended the Bichsel energy loss distributions to handle slower moving ions as well. In this talk, I will discuss a combined approach which successfully extends the dynamic range of the TPC electronics. This work is supported by the U.S. DOE under Grant Nos. DE-SC0014530, DE-NA0002923, US NSF Grant No. PHY-1565546 and the Japan MEXT KAKENHI Grant No. 24105004.

  19. The study of error for analysis in dynamic image from the error of count rates in Nal (Tl) scintillation camera

    International Nuclear Information System (INIS)

    Oh, Joo Young; Kang, Chun Goo; Kim, Jung Yul; Oh, Ki Baek; Kim, Jae Sam; Park, Hoon Hee

    2013-01-01

    This study is aimed to evaluate the effect of T 1/2 upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with '9 9m TcO 4 - of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in χ 2 test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of T 1/2 error from change of gradient with -0.25% to +0.25%, if T 1/2 is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see T 1/2 error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a

  20. A semi-automatic image-based close range 3D modeling pipeline using a multi-camera configuration.

    Science.gov (United States)

    Rau, Jiann-Yeou; Yeh, Po-Chia

    2012-01-01

    The generation of photo-realistic 3D models is an important task for digital recording of cultural heritage objects. This study proposes an image-based 3D modeling pipeline which takes advantage of a multi-camera configuration and multi-image matching technique that does not require any markers on or around the object. Multiple digital single lens reflex (DSLR) cameras are adopted and fixed with invariant relative orientations. Instead of photo-triangulation after image acquisition, calibration is performed to estimate the exterior orientation parameters of the multi-camera configuration which can be processed fully automatically using coded targets. The calibrated orientation parameters of all cameras are applied to images taken using the same camera configuration. This means that when performing multi-image matching for surface point cloud generation, the orientation parameters will remain the same as the calibrated results, even when the target has changed. Base on this invariant character, the whole 3D modeling pipeline can be performed completely automatically, once the whole system has been calibrated and the software was seamlessly integrated. Several experiments were conducted to prove the feasibility of the proposed system. Images observed include that of a human being, eight Buddhist statues, and a stone sculpture. The results for the stone sculpture, obtained with several multi-camera configurations were compared with a reference model acquired by an ATOS-I 2M active scanner. The best result has an absolute accuracy of 0.26 mm and a relative accuracy of 1:17,333. It demonstrates the feasibility of the proposed low-cost image-based 3D modeling pipeline and its applicability to a large quantity of antiques stored in a museum.

  1. Low Power High Dynamic Range A/D Conversion Channel

    DEFF Research Database (Denmark)

    Marker-Villumsen, Niels; Rombach, Pirmin

    in the conversion channel in order to avoid distortion for large input signals. In combination with a low resolution A/D converter (ADC) and a digital gain block, the adaptive A/D conversion channel achieves an extended dynamic range beyond that of the ADC. This in turn reduces the current consumption......This work concerns the analysis of an adaptive analog-to-digital (A/D) conversion channel for use with a micro electromechanical system (MEMS) microphone for audio applications. The adaptive A/D conversion channel uses an automatic gain control (AGC) for adjusting the analog preamplifier gain...... of the conversion channel in comparison to a static A/D conversion channel; this at the cost of a reduced peak signal-to-noise ratio (SNR). The adaptive A/D conversion channel compensates for the change in analog gain by a digital gain, thus achieving a constant channel gain in the full dynamic range. However...

  2. Sensitivity and Dynamic Range Considerations for Homodyne Detection Systems

    DEFF Research Database (Denmark)

    Jaggard, Dwight L.; King, Ray J

    1973-01-01

    The effects of modulation frequency, RF reference power, and external bias upon the sensitivity and dynamic range of microwave homodyne detection systems was measured for point contact diodes and low l/f noise Schottky and backward diodes. The measurements were made at 4.89 GHz using a signal...... to noise ratio of 3 dB and a detection system bandwidth of 10 Hz. Maximum sensitivities of -135, -150, and -145 dBm, and dynamic ranges of 92, 110, and 124 dB were measured for the point contact, Schottky, and backward diodes at modulation frequencies of 30, 30, and 3 kHz, respectively. It was found...... that the level of RF reference signal needed to obtain the maximum sensitivity was equal to or somewhat above the point where the diode changes from square law to linear detection. The results are significant in that previously reported homodyne sensitivities (not necessarily maximum) were on the order of -90...

  3. Gamut mapping in a high-dynamic-range color space

    Science.gov (United States)

    Preiss, Jens; Fairchild, Mark D.; Ferwerda, James A.; Urban, Philipp

    2014-01-01

    In this paper, we present a novel approach of tone mapping as gamut mapping in a high-dynamic-range (HDR) color space. High- and low-dynamic-range (LDR) images as well as device gamut boundaries can simultaneously be represented within such a color space. This enables a unified transformation of the HDR image into the gamut of an output device (in this paper called HDR gamut mapping). An additional aim of this paper is to investigate the suitability of a specific HDR color space to serve as a working color space for the proposed HDR gamut mapping. For the HDR gamut mapping, we use a recent approach that iteratively minimizes an image-difference metric subject to in-gamut images. A psychophysical experiment on an HDR display shows that the standard reproduction workflow of two subsequent transformations - tone mapping and then gamut mapping - may be improved by HDR gamut mapping.

  4. Hierarchical tone mapping for high dynamic range image visualization

    Science.gov (United States)

    Qiu, Guoping; Duan, Jiang

    2005-07-01

    In this paper, we present a computationally efficient, practically easy to use tone mapping techniques for the visualization of high dynamic range (HDR) images in low dynamic range (LDR) reproduction devices. The new method, termed hierarchical nonlinear linear (HNL) tone-mapping operator maps the pixels in two hierarchical steps. The first step allocates appropriate numbers of LDR display levels to different HDR intensity intervals according to the pixel densities of the intervals. The second step linearly maps the HDR intensity intervals to theirs allocated LDR display levels. In the developed HNL scheme, the assignment of LDR display levels to HDR intensity intervals is controlled by a very simple and flexible formula with a single adjustable parameter. We also show that our new operators can be used for the effective enhancement of ordinary images.

  5. Note: A high dynamic range, linear response transimpedance amplifier.

    Science.gov (United States)

    Eckel, S; Sushkov, A O; Lamoreaux, S K

    2012-02-01

    We have built a high dynamic range (nine decade) transimpedance amplifier with a linear response. The amplifier uses junction-gate field effect transistors (JFETs) to switch between three different resistors in the feedback of a low input bias current operational amplifier. This allows for the creation of multiple outputs, each with a linear response and a different transimpedance gain. The overall bandwidth of the transimpedance amplifier is set by the bandwidth of the most sensitive range. For our application, we demonstrate a three-stage amplifier with transimpedance gains of approximately 10(9)Ω, 3 × 10(7)Ω, and 10(4)Ω with a bandwidth of 100 Hz.

  6. Dynamic range extension of BPM at the NSLS

    International Nuclear Information System (INIS)

    Bordoley, M.

    1993-01-01

    In order to overcome range limitations, the existing Beam Position Monitor (BPM) receiver was modified, extending the dynamic range from 35 dB to 60 dB. The modifications include the insertion of an RF PIN attenuator, RF amplifier, and control circuitry in line with the RF link to add an extra 25dB to the existing AGC loop. This stand alone 25dB RF gain control stage is integrated into the present system without any change to the existing receiver

  7. 32x32 HgCdTe/CCD infrared camera for the 2-5 micron range

    International Nuclear Information System (INIS)

    Monin, J.L.; Vauglin, I.; Sibille, F.

    1988-01-01

    The paper presents a complete infrared camera system, based on a high electron capacity detector (HgCdTe/CCD), that has been used under high background conditions to generate astronomical images. The performance of the system and some results are presented, and the use of such a detector in astronomy is discussed. 8 references

  8. Invited article: The fast readout low noise camera as a versatile x-ray detector for time resolved dispersive extended x-ray absorption fine structure and diffraction studies of dynamic problems in materials science, chemistry, and catalysis

    International Nuclear Information System (INIS)

    Labiche, Jean-Claude; Mathon, Olivier; Pascarelli, Sakura; Newton, Mark A.; Ferre, Gemma Guilera; Curfs, Caroline; Vaughan, Gavin; Homs, Alejandro; Carreiras, David Fernandez

    2007-01-01

    Originally conceived and developed at the European Synchrotron Radiation Facility (ESRF) as an 'area' detector for rapid x-ray imaging studies, the fast readout low noise (FReLoN) detector of the ESRF [J.-C. Labiche, ESRF Newsletter 25, 41 (1996)] has been demonstrated to be a highly versatile and unique detector. Charge coupled device (CCD) cameras at present available on the public market offer either a high dynamic range or a high readout speed. A compromise between signal dynamic range and readout speed is always sought. The parameters of the commercial cameras can sometimes be tuned, in order to better fulfill the needs of specific experiments, but in general these cameras have a poor duty cycle (i.e., the signal integration time is much smaller than the readout time). In order to address scientific problems such as time resolved experiments at the ESRF, a FReLoN camera has been developed by the Instrument Support Group at ESRF. This camera is a low noise CCD camera that combines high dynamic range, high readout speed, accuracy, and improved duty cycle in a single image. In this paper, we show its application in a quasi-one-dimensional sense to dynamic problems in materials science, catalysis, and chemistry that require data acquisition on a time scale of milliseconds or a few tens of milliseconds. It is demonstrated that in this mode the FReLoN can be applied equally to the investigation of rapid changes in long range order (via diffraction) and local order (via energy dispersive extended x-ray absorption fine structure) and in situations of x-ray hardness and flux beyond the capacity of other detectors

  9. Assessment and Calibration of a RGB-D Camera (Kinect v2 Sensor Towards a Potential Use for Close-Range 3D Modeling

    Directory of Open Access Journals (Sweden)

    Elise Lachat

    2015-10-01

    Full Text Available In the last decade, RGB-D cameras - also called range imaging cameras - have known a permanent evolution. Because of their limited cost and their ability to measure distances at a high frame rate, such sensors are especially appreciated for applications in robotics or computer vision. The Kinect v1 (Microsoft release in November 2010 promoted the use of RGB-D cameras, so that a second version of the sensor arrived on the market in July 2014. Since it is possible to obtain point clouds of an observed scene with a high frequency, one could imagine applying this type of sensors to answer to the need for 3D acquisition. However, due to the technology involved, some questions have to be considered such as, for example, the suitability and accuracy of RGB-D cameras for close range 3D modeling. In that way, the quality of the acquired data represents a major axis. In this paper, the use of a recent Kinect v2 sensor to reconstruct small objects in three dimensions has been investigated. To achieve this goal, a survey of the sensor characteristics as well as a calibration approach are relevant. After an accuracy assessment of the produced models, the benefits and drawbacks of Kinect v2 compared to the first version of the sensor and then to photogrammetry are discussed.

  10. POTENTIALS OF IMAGE BASED ACTIVE RANGING TO CAPTURE DYNAMIC SCENES

    Directory of Open Access Journals (Sweden)

    B. Jutzi

    2012-09-01

    Full Text Available Obtaining a 3D description of man-made and natural environments is a basic task in Computer Vision and Remote Sensing. To this end, laser scanning is currently one of the dominating techniques to gather reliable 3D information. The scanning principle inherently needs a certain time interval to acquire the 3D point cloud. On the other hand, new active sensors provide the possibility of capturing range information by images with a single measurement. With this new technique image-based active ranging is possible which allows capturing dynamic scenes, e.g. like walking pedestrians in a yard or moving vehicles. Unfortunately most of these range imaging sensors have strong technical limitations and are not yet sufficient for airborne data acquisition. It can be seen from the recent development of highly specialized (far-range imaging sensors – so called flash-light lasers – that most of the limitations could be alleviated soon, so that future systems will be equipped with improved image size and potentially expanded operating range. The presented work is a first step towards the development of methods capable for application of range images in outdoor environments. To this end, an experimental setup was set up for investigating these proposed possibilities. With the experimental setup a measurement campaign was carried out and first results will be presented within this paper.

  11. Dynamic range compression in a liquid argon calorimeter

    International Nuclear Information System (INIS)

    Cleland, W.E.; Lissauer, D.; Radeka, V.; Rescia, S.; Takai, H.; Wingerter-Seez, I.

    1996-01-01

    The anticipated range of particle energies at the LHC, coupled with the need for precision, low noise calorimetry makes severe demands on the dynamic range of the calorimeter readout. A common approach to this problem is to use shapers with two or more gain scales. In this paper, the authors describe their experience with a new approach in which a preamplifier with dynamic gain compression is used. An unavoidable consequence of dynamic gain adjustment is that the peaking time of the shaper output signal becomes amplitude dependent. The authors have carried out a test of such a readout system in the RD3 calorimeter, a liquid argon device with accordion geometry. The calibration system is used to determine both the gain of the individual channels as well as to map the shape of the waveform as a function of signal amplitude. A new procedure for waveform analysis, in which the fitted parameters describe the impulse response of the system, permits a straightforward translation of the calibration waveform to the waveform generated by a particle crossing the ionization gap. They find that the linearity and resolution of the calorimeter is equivalent to that obtained with linear preamplifiers, up to an energy of 200 GeV

  12. TH-CD-201-10: Highly Efficient Synchronized High-Speed Scintillation Camera System for Measuring Proton Range, SOBP and Dose Distributions in a 2D-Plane

    International Nuclear Information System (INIS)

    Goddu, S; Sun, B; Grantham, K; Zhao, T; Zhang, T; Bradley, J; Mutic, S

    2016-01-01

    Purpose: Proton therapy (PT) delivery is complex and extremely dynamic. Therefore, quality assurance testing is vital, but highly time-consuming. We have developed a High-Speed Scintillation-Camera-System (HS-SCS) for simultaneously measuring multiple beam characteristics. Methods: High-speed camera was placed in a light-tight housing and dual-layer neutron shield. HS-SCS is synchronized with a synchrocyclotron to capture individual proton-beam-pulses (PBPs) at ∼504 frames/sec. The PBPs from synchrocyclotron trigger the HS-SCS to open its shutter for programmed exposure-time. Light emissions within 30×30×5cm3 plastic-scintillator (BC-408) were captured by a CCD-camera as individual images revealing dose-deposition in a 2D-plane with a resolution of 0.7mm for range and SOBP measurements and 1.67mm for profiles. The CCD response as well as signal to noise ratio (SNR) was characterized for varying exposure times, gains for different light intensities using a TV-Optoliner system. Software tools were developed to analyze ∼5000 images to extract different beam parameters. Quenching correction-factors were established by comparing scintillation Bragg-Peaks with water scanned ionization-chamber measurements. Quenching corrected Bragg-peaks were integrated to ascertain proton-beam range (PBR), width of Spared-Out-Bragg-Peak (MOD) and distal

  13. TH-CD-201-10: Highly Efficient Synchronized High-Speed Scintillation Camera System for Measuring Proton Range, SOBP and Dose Distributions in a 2D-Plane

    Energy Technology Data Exchange (ETDEWEB)

    Goddu, S; Sun, B; Grantham, K; Zhao, T; Zhang, T; Bradley, J; Mutic, S [Washington University School of Medicine, Saint Louis, MO (United States)

    2016-06-15

    Purpose: Proton therapy (PT) delivery is complex and extremely dynamic. Therefore, quality assurance testing is vital, but highly time-consuming. We have developed a High-Speed Scintillation-Camera-System (HS-SCS) for simultaneously measuring multiple beam characteristics. Methods: High-speed camera was placed in a light-tight housing and dual-layer neutron shield. HS-SCS is synchronized with a synchrocyclotron to capture individual proton-beam-pulses (PBPs) at ∼504 frames/sec. The PBPs from synchrocyclotron trigger the HS-SCS to open its shutter for programmed exposure-time. Light emissions within 30×30×5cm3 plastic-scintillator (BC-408) were captured by a CCD-camera as individual images revealing dose-deposition in a 2D-plane with a resolution of 0.7mm for range and SOBP measurements and 1.67mm for profiles. The CCD response as well as signal to noise ratio (SNR) was characterized for varying exposure times, gains for different light intensities using a TV-Optoliner system. Software tools were developed to analyze ∼5000 images to extract different beam parameters. Quenching correction-factors were established by comparing scintillation Bragg-Peaks with water scanned ionization-chamber measurements. Quenching corrected Bragg-peaks were integrated to ascertain proton-beam range (PBR), width of Spared-Out-Bragg-Peak (MOD) and distal.

  14. Cloud cover detection combining high dynamic range sky images and ceilometer measurements

    Science.gov (United States)

    Román, R.; Cazorla, A.; Toledano, C.; Olmo, F. J.; Cachorro, V. E.; de Frutos, A.; Alados-Arboledas, L.

    2017-11-01

    This paper presents a new algorithm for cloud detection based on high dynamic range images from a sky camera and ceilometer measurements. The algorithm is also able to detect the obstruction of the sun. This algorithm, called CPC (Camera Plus Ceilometer), is based on the assumption that under cloud-free conditions the sky field must show symmetry. The symmetry criteria are applied depending on ceilometer measurements of the cloud base height. CPC algorithm is applied in two Spanish locations (Granada and Valladolid). The performance of CPC retrieving the sun conditions (obstructed or unobstructed) is analyzed in detail using as reference pyranometer measurements at Granada. CPC retrievals are in agreement with those derived from the reference pyranometer in 85% of the cases (it seems that this agreement does not depend on aerosol size or optical depth). The agreement percentage goes down to only 48% when another algorithm, based on Red-Blue Ratio (RBR), is applied to the sky camera images. The retrieved cloud cover at Granada and Valladolid is compared with that registered by trained meteorological observers. CPC cloud cover is in agreement with the reference showing a slight overestimation and a mean absolute error around 1 okta. A major advantage of the CPC algorithm with respect to the RBR method is that the determined cloud cover is independent of aerosol properties. The RBR algorithm overestimates cloud cover for coarse aerosols and high loads. Cloud cover obtained only from ceilometer shows similar results than CPC algorithm; but the horizontal distribution cannot be obtained. In addition, it has been observed that under quick and strong changes on cloud cover ceilometers retrieve a cloud cover fitting worse with the real cloud cover.

  15. Progress towards a semiconductor Compton camera for prompt gamma imaging during proton beam therapy for range and dose verification

    Science.gov (United States)

    Gutierrez, A.; Baker, C.; Boston, H.; Chung, S.; Judson, D. S.; Kacperek, A.; Le Crom, B.; Moss, R.; Royle, G.; Speller, R.; Boston, A. J.

    2018-01-01

    The main objective of this work is to test a new semiconductor Compton camera for prompt gamma imaging. Our device is composed of three active layers: a Si(Li) detector as a scatterer and two high purity Germanium detectors as absorbers of high-energy gamma rays. We performed Monte Carlo simulations using the Geant4 toolkit to characterise the expected gamma field during proton beam therapy and have made experimental measurements of the gamma spectrum with a 60 MeV passive scattering beam irradiating a phantom. In this proceeding, we describe the status of the Compton camera and present the first preliminary measurements with radioactive sources and their corresponding reconstructed images.

  16. A dynamic range upgrade for neutron backscattering spectroscopy

    International Nuclear Information System (INIS)

    Cook, J.C.; Petry, W.; Heidemann, A.; Barthelemy, J.F.

    1992-01-01

    We report on an instrumental development of the cold neutron backscattering spectrometer IN10 at the Institut Laue-Langevin which has led to a significant increase in its dynamic range. Thermal expansion of a variety of neutron monochromator crystals is used instead of a mechanical oscillation of the monochromator, yielding an increase in the energy transfer range by nearly two orders of magnitude in an elastic wave vector transfer range of 0.07≤Q (A -1 )≤2.0. Using this new configuration, first inelastic measurements have been performed using the (200) reflections from KCl and NaCl monochromators with crystal temperatures between 80 K and 700 K. The thermal expansion of these crystals in this temperature range gives rise to energy transfer ranges (neutron energy gain) of -16<ℎω(μeV)<+83 for KCl and -530<ℎω(μeV)<-420 for NaCl with energy resolution (FWHM) of around 0.6 and 1.4 μeV for KCl and NaCl respectively. These figures represent the highest energy resolution currently available at these energy and wave vector transfers. (orig.)

  17. In-Vivo High Dynamic Range Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2015-01-01

    example with a high dynamic velocity range. Velocities with an order of magnitude apart are detected on the femoral artery of a 41 years old healthy individual. Three distinct heart cycles are captured during a 3 secs acquisition. The estimated vector velocities are compared against each other within...... the heart cycle. The relative standard deviation of the measured velocity magnitude between the three peak systoles was found to be 5.11% with a standard deviation on the detected angle of 1.06◦ . In the diastole, it was 1.46% and 6.18◦ , respectively. Results proves that the method is able to estimate flow...

  18. Increasing the Dynamic Range of Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2014-01-01

    images. The emissions for the two imaging modes are interleaved 1-to-1 ratio, providing a high frame rate equal to the effective pulse repetition frequency of each imaging mode. The direction of the flow is estimated, and the velocity is then determined in that direction. This method Works for all angles...... standard deviations are 1.59% and 6.12%, respectively. The presented method can improve the estimates by synthesizing a lower pulse repetition frequency, thereby increasing the dynamic range of the vector velocity imaging....

  19. An objective method for High Dynamic Range source content selection

    DEFF Research Database (Denmark)

    Narwaria, Manish; Mantel, Claire; Da Silva, Matthieu Perreira

    2014-01-01

    With the aim of improving the immersive experience of the end user, High Dynamic Range (HDR) imaging has been gaining popularity. Therefore, proper validation and performance benchmarking of HDR processing algorithms is a key step towards standardization and commercial deployment. A crucial...... component of such validation studies is the selection of a challenging and balanced set of source (reference) HDR content. In order to facilitate this, we present an objective method based on the premise that a more challenging HDR scene encapsulates higher contrast, and as a result will show up more...

  20. Abstract of Dynamic Range: When Game Design and Narratives Unite

    OpenAIRE

    Arsenault, Dominic

    2005-01-01

    This paper proposes a tool and methodology for measuring the degree of freedom given to a player in any resource-driven game (that is, any game in which managing resources is an integral part of the gameplay). This concept, which I call the Dynamic Range, can be used namely to evaluate a given game system’s potential for developing emergent narratives, as defined by Henry Jenkins in his publication Game Design as Narrative Architecture. While Jenkins places at the heart of the creation of nar...

  1. The MOLDY short-range molecular dynamics package

    Science.gov (United States)

    Ackland, G. J.; D'Mellow, K.; Daraszewicz, S. L.; Hepburn, D. J.; Uhrin, M.; Stratford, K.

    2011-12-01

    We describe a parallelised version of the MOLDY molecular dynamics program. This Fortran code is aimed at systems which may be described by short-range potentials and specifically those which may be addressed with the embedded atom method. This includes a wide range of transition metals and alloys. MOLDY provides a range of options in terms of the molecular dynamics ensemble used and the boundary conditions which may be applied. A number of standard potentials are provided, and the modular structure of the code allows new potentials to be added easily. The code is parallelised using OpenMP and can therefore be run on shared memory systems, including modern multicore processors. Particular attention is paid to the updates required in the main force loop, where synchronisation is often required in OpenMP implementations of molecular dynamics. We examine the performance of the parallel code in detail and give some examples of applications to realistic problems, including the dynamic compression of copper and carbon migration in an iron-carbon alloy. Program summaryProgram title: MOLDY Catalogue identifier: AEJU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 2 No. of lines in distributed program, including test data, etc.: 382 881 No. of bytes in distributed program, including test data, etc.: 6 705 242 Distribution format: tar.gz Programming language: Fortran 95/OpenMP Computer: Any Operating system: Any Has the code been vectorised or parallelized?: Yes. OpenMP is required for parallel execution RAM: 100 MB or more Classification: 7.7 Nature of problem: Moldy addresses the problem of many atoms (of order 10 6) interacting via a classical interatomic potential on a timescale of microseconds. It is designed for problems where statistics must be gathered over a number of equivalent runs, such as

  2. Improvement of Lambert-Beer law dynamic range by the use of temporal gates on transmitted light pulse through a scattering medium

    International Nuclear Information System (INIS)

    Yoshino, Hironori; Wada, Kenji; Horinaka, Hiromichi; Cho, Yoshio; Umeda, Tokuo; Osawa, Masahiko.

    1995-01-01

    The Lambert-Beer law holding for pulsed lights transmitted through a scattering medium was examined using a streak camera. The Lambert-Beer law dynamic range is found to be limited by floor levels that are caused by scattered photons and are controllable by the use of a temporal gate on the transmitted pulse. The dynamic range improvement obtained for a scattering medium of 2.8 cm -1 scattering coefficient of a thickness of 80 mm by a temporal gate of 60 ps was as much as 50 dB and the Lambert-Beer law dynamic rang reached to 140 dB. (author)

  3. Mangrove microclimates alter seedling dynamics at the range edge.

    Science.gov (United States)

    Devaney, John L; Lehmann, Michael; Feller, Ilka C; Parker, John D

    2017-10-01

    Recent climate warming has led to asynchronous species migrations, with major consequences for ecosystems worldwide. In woody communities, localized microclimates have the potential to create feedback mechanisms that can alter the rate of species range shifts attributed to macroclimate drivers alone. Mangrove encroachment into saltmarsh in many areas is driven by a reduction in freeze events, and this encroachment can further modify local climate, but the subsequent impacts on mangrove seedling dynamics are unknown. We monitored microclimate conditions beneath mangrove canopies and adjacent open saltmarsh at a freeze-sensitive mangrove-saltmarsh ecotone and assessed survival of experimentally transplanted mangrove seedlings. Mangrove canopies buffered night time cooling during the winter, leading to interspecific differences in freeze damage on mangrove seedlings. However, mangrove canopies also altered biotic interactions. Herbivore damage was higher under canopies, leading to greater mangrove seedling mortality beneath canopies relative to saltmarsh. While warming-induced expansion of mangroves can lead to positive microclimate feedbacks, simultaneous fluctuations in biotic drivers can also alter seedling dynamics. Thus, climate change can drive divergent feedback mechanisms through both abiotic and biotic channels, highlighting the importance of vegetation-microclimate interactions as important moderators of climate driven range shifts. © 2017 by the Ecological Society of America.

  4. First full dynamic range calibration of the JUNGFRAU photon detector

    Science.gov (United States)

    Redford, S.; Andrä, M.; Barten, R.; Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Fröjdh, E.; Greiffenberg, D.; Lopez-Cuenca, C.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruat, M.; Ruder, C.; Schmitt, B.; Shi, X.; Thattil, D.; Tinti, G.; Vetter, S.; Zhang, J.

    2018-01-01

    The JUNGFRAU detector is a charge integrating hybrid silicon pixel detector developed at the Paul Scherrer Institut for photon science applications, in particular for the upcoming free electron laser SwissFEL. With a high dynamic range, analogue readout, low noise and three automatically switching gains, JUNGFRAU promises excellent performance not only at XFELs but also at synchrotrons in areas such as protein crystallography, ptychography, pump-probe and time resolved measurements. To achieve its full potential, the detector must be calibrated on a pixel-by-pixel basis. This contribution presents the current status of the JUNGFRAU calibration project, in which a variety of input charge sources are used to parametrise the energy response of the detector across four orders of magnitude of dynamic range. Building on preliminary studies, the first full calibration procedure of a JUNGFRAU 0.5 Mpixel module is described. The calibration is validated using alternative sources of charge deposition, including laboratory experiments and measurements at ESRF and LCLS. The findings from these measurements are presented. Calibrated modules have already been used in proof-of-principle style protein crystallography experiments at the SLS. A first look at selected results is shown. Aspects such as the conversion of charge to number of photons, treatment of multi-size pixels and the origin of non-linear response are also discussed.

  5. Increasing Linear Dynamic Range of a CMOS Image Sensor

    Science.gov (United States)

    Pain, Bedabrata

    2007-01-01

    A generic design and a corresponding operating sequence have been developed for increasing the linear-response dynamic range of a complementary metal oxide/semiconductor (CMOS) image sensor. The design provides for linear calibrated dual-gain pixels that operate at high gain at a low signal level and at low gain at a signal level above a preset threshold. Unlike most prior designs for increasing dynamic range of an image sensor, this design does not entail any increase in noise (including fixed-pattern noise), decrease in responsivity or linearity, or degradation of photometric calibration. The figure is a simplified schematic diagram showing the circuit of one pixel and pertinent parts of its column readout circuitry. The conventional part of the pixel circuit includes a photodiode having a small capacitance, CD. The unconventional part includes an additional larger capacitance, CL, that can be connected to the photodiode via a transfer gate controlled in part by a latch. In the high-gain mode, the signal labeled TSR in the figure is held low through the latch, which also helps to adapt the gain on a pixel-by-pixel basis. Light must be coupled to the pixel through a microlens or by back illumination in order to obtain a high effective fill factor; this is necessary to ensure high quantum efficiency, a loss of which would minimize the efficacy of the dynamic- range-enhancement scheme. Once the level of illumination of the pixel exceeds the threshold, TSR is turned on, causing the transfer gate to conduct, thereby adding CL to the pixel capacitance. The added capacitance reduces the conversion gain, and increases the pixel electron-handling capacity, thereby providing an extension of the dynamic range. By use of an array of comparators also at the bottom of the column, photocharge voltages on sampling capacitors in each column are compared with a reference voltage to determine whether it is necessary to switch from the high-gain to the low-gain mode. Depending upon

  6. Context-dependent JPEG backward-compatible high-dynamic range image compression

    Science.gov (United States)

    Korshunov, Pavel; Ebrahimi, Touradj

    2013-10-01

    High-dynamic range (HDR) imaging is expected, together with ultrahigh definition and high-frame rate video, to become a technology that may change photo, TV, and film industries. Many cameras and displays capable of capturing and rendering both HDR images and video are already available in the market. The popularity and full-public adoption of HDR content is, however, hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of low-dynamic range (LDR) displays that are unable to render HDR. To facilitate the wide spread of HDR usage, the backward compatibility of HDR with commonly used legacy technologies for storage, rendering, and compression of video and images are necessary. Although many tone-mapping algorithms are developed for generating viewable LDR content from HDR, there is no consensus of which algorithm to use and under which conditions. We, via a series of subjective evaluations, demonstrate the dependency of the perceptual quality of the tone-mapped LDR images on the context: environmental factors, display parameters, and image content itself. Based on the results of subjective tests, it proposes to extend JPEG file format, the most popular image format, in a backward compatible manner to deal with HDR images also. An architecture to achieve such backward compatibility with JPEG is proposed. A simple implementation of lossy compression demonstrates the efficiency of the proposed architecture compared with the state-of-the-art HDR image compression.

  7. An improved method to estimate reflectance parameters for high dynamic range imaging

    Science.gov (United States)

    Li, Shiying; Deguchi, Koichiro; Li, Renfa; Manabe, Yoshitsugu; Chihara, Kunihiro

    2008-01-01

    Two methods are described to accurately estimate diffuse and specular reflectance parameters for colors, gloss intensity and surface roughness, over the dynamic range of the camera used to capture input images. Neither method needs to segment color areas on an image, or to reconstruct a high dynamic range (HDR) image. The second method improves on the first, bypassing the requirement for specific separation of diffuse and specular reflection components. For the latter method, diffuse and specular reflectance parameters are estimated separately, using the least squares method. Reflection values are initially assumed to be diffuse-only reflection components, and are subjected to the least squares method to estimate diffuse reflectance parameters. Specular reflection components, obtained by subtracting the computed diffuse reflection components from reflection values, are then subjected to a logarithmically transformed equation of the Torrance-Sparrow reflection model, and specular reflectance parameters for gloss intensity and surface roughness are finally estimated using the least squares method. Experiments were carried out using both methods, with simulation data at different saturation levels, generated according to the Lambert and Torrance-Sparrow reflection models, and the second method, with spectral images captured by an imaging spectrograph and a moving light source. Our results show that the second method can estimate the diffuse and specular reflectance parameters for colors, gloss intensity and surface roughness more accurately and faster than the first one, so that colors and gloss can be reproduced more efficiently for HDR imaging.

  8. Utilization and viability of biologically-inspired algorithms in a dynamic multiagent camera surveillance system

    Science.gov (United States)

    Mundhenk, Terrell N.; Dhavale, Nitin; Marmol, Salvador; Calleja, Elizabeth; Navalpakkam, Vidhya; Bellman, Kirstie; Landauer, Chris; Arbib, Michael A.; Itti, Laurent

    2003-10-01

    In view of the growing complexity of computational tasks and their design, we propose that certain interactive systems may be better designed by utilizing computational strategies based on the study of the human brain. Compared with current engineering paradigms, brain theory offers the promise of improved self-organization and adaptation to the current environment, freeing the programmer from having to address those issues in a procedural manner when designing and implementing large-scale complex systems. To advance this hypothesis, we discus a multi-agent surveillance system where 12 agent CPUs each with its own camera, compete and cooperate to monitor a large room. To cope with the overload of image data streaming from 12 cameras, we take inspiration from the primate"s visual system, which allows the animal to operate a real-time selection of the few most conspicuous locations in visual input. This is accomplished by having each camera agent utilize the bottom-up, saliency-based visual attention algorithm of Itti and Koch (Vision Research 2000;40(10-12):1489-1506) to scan the scene for objects of interest. Real time operation is achieved using a distributed version that runs on a 16-CPU Beowulf cluster composed of the agent computers. The algorithm guides cameras to track and monitor salient objects based on maps of color, orientation, intensity, and motion. To spread camera view points or create cooperation in monitoring highly salient targets, camera agents bias each other by increasing or decreasing the weight of different feature vectors in other cameras, using mechanisms similar to excitation and suppression that have been documented in electrophysiology, psychophysics and imaging studies of low-level visual processing. In addition, if cameras need to compete for computing resources, allocation of computational time is weighed based upon the history of each camera. A camera agent that has a history of seeing more salient targets is more likely to obtain

  9. Developing a CCD camera with high spatial resolution for RIXS in the soft X-ray range

    Science.gov (United States)

    Soman, M. R.; Hall, D. J.; Tutt, J. H.; Murray, N. J.; Holland, A. D.; Schmitt, T.; Raabe, J.; Schmitt, B.

    2013-12-01

    The Super Advanced X-ray Emission Spectrometer (SAXES) at the Swiss Light Source contains a high resolution Charge-Coupled Device (CCD) camera used for Resonant Inelastic X-ray Scattering (RIXS). Using the current CCD-based camera system, the energy-dispersive spectrometer has an energy resolution (E/ΔE) of approximately 12,000 at 930 eV. A recent study predicted that through an upgrade to the grating and camera system, the energy resolution could be improved by a factor of 2. In order to achieve this goal in the spectral domain, the spatial resolution of the CCD must be improved to better than 5 μm from the current 24 μm spatial resolution (FWHM). The 400 eV-1600 eV energy X-rays detected by this spectrometer primarily interact within the field free region of the CCD, producing electron clouds which will diffuse isotropically until they reach the depleted region and buried channel. This diffusion of the charge leads to events which are split across several pixels. Through the analysis of the charge distribution across the pixels, various centroiding techniques can be used to pinpoint the spatial location of the X-ray interaction to the sub-pixel level, greatly improving the spatial resolution achieved. Using the PolLux soft X-ray microspectroscopy endstation at the Swiss Light Source, a beam of X-rays of energies from 200 eV to 1400 eV can be focused down to a spot size of approximately 20 nm. Scanning this spot across the 16 μm square pixels allows the sub-pixel response to be investigated. Previous work has demonstrated the potential improvement in spatial resolution achievable by centroiding events in a standard CCD. An Electron-Multiplying CCD (EM-CCD) has been used to improve the signal to effective readout noise ratio achieved resulting in a worst-case spatial resolution measurement of 4.5±0.2 μm and 3.9±0.1 μm at 530 eV and 680 eV respectively. A method is described that allows the contribution of the X-ray spot size to be deconvolved from these

  10. Kernel optimization for short-range molecular dynamics

    Science.gov (United States)

    Hu, Changjun; Wang, Xianmeng; Li, Jianjiang; He, Xinfu; Li, Shigang; Feng, Yangde; Yang, Shaofeng; Bai, He

    2017-02-01

    To optimize short-range force computations in Molecular Dynamics (MD) simulations, multi-threading and SIMD optimizations are presented in this paper. With respect to multi-threading optimization, a Partition-and-Separate-Calculation (PSC) method is designed to avoid write conflicts caused by using Newton's third law. Serial bottlenecks are eliminated with no additional memory usage. The method is implemented by using the OpenMP model. Furthermore, the PSC method is employed on Intel Xeon Phi coprocessors in both native and offload models. We also evaluate the performance of the PSC method under different thread affinities on the MIC architecture. In the SIMD execution, we explain the performance influence in the PSC method, considering the "if-clause" of the cutoff radius check. The experiment results show that our PSC method is relatively more efficient compared to some traditional methods. In double precision, our 256-bit SIMD implementation is about 3 times faster than the scalar version.

  11. Effects of dynamic-range compression on temporal acuity

    DEFF Research Database (Denmark)

    Wiinberg, Alan; Jepsen, Morten Løve; Epp, Bastian

    2016-01-01

    Some of the challenges that hearing-aid listeners experience with speech perception in complex acoustic environments may originate from limitations in the temporal processing of sounds. To systematically investigate the influence of hearing impairment and hearing-aid signal processing on temporal...... processing, temporal modulation transfer functions (TMTFs) and “supra-threshold” modulation-depth discrimination (MDD) thresholds were obtained in normal-hearing (NH) and hearing-impaired (HI) listeners with and without wide-dynamic range compression (WDRC). The TMTFs were obtained using tonal carriers of 1...... with the physical compression of the modulation depth due to the WDRC. Indications of reduced temporal resolution in the HI listeners were observed in the TMTF patterns for the 5 kHz carrier. Significantly higher MDD thresholds were found for the HI group relative to the NH group. No relationship was found between...

  12. An Integrated Tone Mapping for High Dynamic Range Image Visualization

    Science.gov (United States)

    Liang, Lei; Pan, Jeng-Shyang; Zhuang, Yongjun

    2018-01-01

    There are two type tone mapping operators for high dynamic range (HDR) image visualization. HDR image mapped by perceptual operators have strong sense of reality, but will lose local details. Empirical operators can maximize local detail information of HDR image, but realism is not strong. A common tone mapping operator suitable for all applications is not available. This paper proposes a novel integrated tone mapping framework which can achieve conversion between empirical operators and perceptual operators. In this framework, the empirical operator is rendered based on improved saliency map, which simulates the visual attention mechanism of the human eye to the natural scene. The results of objective evaluation prove the effectiveness of the proposed solution.

  13. Computational model of lightness perception in high dynamic range imaging

    Science.gov (United States)

    Krawczyk, Grzegorz; Myszkowski, Karol; Seidel, Hans-Peter

    2006-02-01

    An anchoring theory of lightness perception by Gilchrist et al. [1999] explains many characteristics of human visual system such as lightness constancy and its spectacular failures which are important in the perception of images. The principal concept of this theory is the perception of complex scenes in terms of groups of consistent areas (frameworks). Such areas, following the gestalt theorists, are defined by the regions of common illumination. The key aspect of the image perception is the estimation of lightness within each framework through the anchoring to the luminance perceived as white, followed by the computation of the global lightness. In this paper we provide a computational model for automatic decomposition of HDR images into frameworks. We derive a tone mapping operator which predicts lightness perception of the real world scenes and aims at its accurate reproduction on low dynamic range displays. Furthermore, such a decomposition into frameworks opens new grounds for local image analysis in view of human perception.

  14. Development of a Compton camera for online ion beam range verification via prompt γ detection. Session: HK 12.6 Mo 18:30

    Energy Technology Data Exchange (ETDEWEB)

    Aldawood, S. [LMU Munich, Garching (Germany); King Saud University, Riyadh (Saudi Arabia); Liprandi, S.; Marinsek, T.; Bortfeldt, J.; Lang, C.; Lutter, R.; Dedes, G.; Parodi, K.; Thirolf, P.G. [LMU Munich, Garching (Germany); Maier, L.; Gernhaeuser, R. [TU Munich, Garching (Germany); Kolff, H. van der; Schaart, D. [TU Delft (Netherlands); Castelhano, I. [University of Lisbon, Lisbon (Portugal)

    2015-07-01

    A real-time ion beam verification in hadron-therapy is playing a major role in cancer treatment evaluation. This will make the treatment interuption possible if the planned and actual ion range are mismatched. An imaging system is being developed in Garching aiming to detect prompt γ rays induced by nuclear reactions between the ion beam and biological tissue. The Compton camera prototype consists of a stack of six customized double-sided Si-strip detectors (DSSSD, 50 x 50 mm{sup 2}, 128 strips/side) acting as scatterer, while the absorber is formed by a monolithic LaBr{sub 3}:Ce scintillator crystal (50 x 50 x 30 mm{sup 3}) read out by a position-sensitive multi-anode photomultiplier (Hamamatsu H9500). The study of the Compton camera properties and its individual component are in progress both in the laboratory as well as at the online facilities.

  15. Clinical evaluation of a medical high dynamic range display

    International Nuclear Information System (INIS)

    Marchessoux, Cedric; Paepe, Lode de; Vanovermeire, Olivier; Albani, Luigi

    2016-01-01

    Purpose: Recent new medical displays do have higher contrast and higher luminance but do not have a High Dynamic Range (HDR). HDR implies a minimum luminance value close to zero. A medical HDR display prototype based on two Liquid Crystal layers has been developed. The goal of this study is to evaluate the potential clinical benefit of such display in comparison with a low dynamic range (LDR) display. Methods: The study evaluated the clinical performance of the displays in a search and detection task. Eight radiologists read chest x-ray images some of which contained simulated lung nodules. The study used a JAFROC (Jacknife Free Receiver Operating Characteristic) approach for analyzing FROC data. The calculated figure of merit (FoM) is the probability that a lesion is rated higher than all rated nonlesions on all images. Time per case and accuracy for locating the center of the nodules were also compared. The nodules were simulated using Samei’s model. 214 CR and DR images [half were “healthy images” (chest nodule-free) and half “diseased images”] were used resulting in a total number of nodules equal to 199 with 25 images with 1 nodule, 51 images with 2 nodules, and 24 images with 3 nodules. A dedicated software interface was designed for visualizing the images for each session. For the JAFROC1 statistical analysis, the study is done per nodule category: all nodules, difficult nodules, and very difficult nodules. Results: For all nodules, the averaged FoM HDR is slightly higher than FoM LDR with 0.09% of difference. For the difficult nodules, the averaged FoM HDR is slightly higher than FoM LDR with 1.38% of difference. The averaged FoM HDR is slightly higher than FoM LDR with 0.71% of difference. For the true positive fraction (TPF), both displays (the HDR and the LDR ones) have similar TPF for all nodules, but looking at difficult and very difficult nodules, there are more TP for the HDR display. The true positive fraction has been also computed in

  16. Binaural model-based dynamic-range compression.

    Science.gov (United States)

    Ernst, Stephan M A; Kortlang, Steffen; Grimm, Giso; Bisitz, Thomas; Kollmeier, Birger; Ewert, Stephan D

    2018-01-26

    Binaural cues such as interaural level differences (ILDs) are used to organise auditory perception and to segregate sound sources in complex acoustical environments. In bilaterally fitted hearing aids, dynamic-range compression operating independently at each ear potentially alters these ILDs, thus distorting binaural perception and sound source segregation. A binaurally-linked model-based fast-acting dynamic compression algorithm designed to approximate the normal-hearing basilar membrane (BM) input-output function in hearing-impaired listeners is suggested. A multi-center evaluation in comparison with an alternative binaural and two bilateral fittings was performed to assess the effect of binaural synchronisation on (a) speech intelligibility and (b) perceived quality in realistic conditions. 30 and 12 hearing impaired (HI) listeners were aided individually with the algorithms for both experimental parts, respectively. A small preference towards the proposed model-based algorithm in the direct quality comparison was found. However, no benefit of binaural-synchronisation regarding speech intelligibility was found, suggesting a dominant role of the better ear in all experimental conditions. The suggested binaural synchronisation of compression algorithms showed a limited effect on the tested outcome measures, however, linking could be situationally beneficial to preserve a natural binaural perception of the acoustical environment.

  17. Cochlear function tests in estimation of speech dynamic range.

    Science.gov (United States)

    Han, Jung Ju; Park, So Young; Park, Shi Nae; Na, Mi Sun; Lee, Philip; Han, Jae Sang

    2016-10-01

    The loss of active cochlear mechanics causes elevated thresholds, loudness recruitment, and reduced frequency selectivity. The problems faced by hearing-impaired listeners are largely related with reduced dynamic range (DR). The aim of this study was to determine which index of the cochlear function tests correlates best with the DR to speech stimuli. Audiological data on 516 ears with pure tone average (PTA) of ≤55 dB and word recognition score of ≥70% were analyzed. PTA, speech recognition threshold (SRT), uncomfortable loudness (UCL), and distortion product otoacoustic emission (DPOAE) were explored as the indices of cochlear function. Audiometric configurations were classified. Correlation between each index and the DR was assessed and multiple regression analysis was done. PTA and SRT demonstrated strong negative correlations with the DR (r = -0.788 and -0.860, respectively), while DPOAE sum was moderately correlated (r = 0.587). UCLs remained quite constant for the total range of the DR. The regression equation was Y (DR) = 75.238 - 0.719 × SRT (R(2 )=( )0.721, p equation.

  18. Dynamical scene analysis with a moving camera: mobile targets detection system

    International Nuclear Information System (INIS)

    Hennebert, Christine

    1996-01-01

    This thesis work deals with the detection of moving objects in monocular image sequences acquired with a mobile camera. We propose a method able to detect small moving objects in visible or infrared images of real outdoor scenes. In order to detect objects of very low apparent motion, we consider an analysis on a large temporal interval. We have chosen to compensate for the dominant motion due to the camera displacement for several consecutive images in order to form a sub-sequence of images for which the camera seems virtually static. We have also developed a new approach allowing to extract the different layers of a real scene in order to deal with cases where the 2D motion due to the camera displacement cannot be globally compensated for. To this end, we use a hierarchical model with two levels: the local merging step and the global merging one. Then, an appropriate temporal filtering is applied to registered image sub-sequence to enhance signals corresponding to moving objects. The detection issue is stated as a labeling problem within a statistical regularization based on Markov Random Fields. Our method has been validated on numerous real image sequences depicting complex outdoor scenes. Finally, the feasibility of an integrated circuit for mobile object detection has been proved. This circuit could lead to an ASIC creation. (author) [fr

  19. Range use and dynamics in the agropastoral system of ...

    African Journals Online (AJOL)

    Occurrence of equilibrium and non equilibrium system dynamics in semiarid environments present serious management challenges. In these areas, resource management strategies are increasingly based on equilibrium rather than non equilibrium dynamics that assume simple system dynamics and strong coupling of ...

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

    Directory of Open Access Journals (Sweden)

    Leitritz MA

    2014-07-01

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

  1. Dynamic range of atomically thin vibrating nanomechanical resonators

    International Nuclear Information System (INIS)

    Wang, Zenghui; Feng, Philip X.-L.

    2014-01-01

    Atomically thin two-dimensional (2D) crystals offer attractive properties for making resonant nanoelectromechanical systems (NEMS) operating at high frequencies. While the fundamental limits of linear operation in such systems are important, currently there is very little quantitative knowledge of the linear dynamic range (DR) and onset of nonlinearity in these devices, which are different than in conventional 1D NEMS such as nanotubes and nanowires. Here, we present theoretical analysis and quantitative models that can be directly used to predict the DR of vibrating 2D circular drumhead NEMS resonators. We show that DR has a strong dependence ∝10log(E Y 3/2 ρ 3D -1/2 rtε 5/2 ) on device parameters, in which strain ε plays a particularly important role in these 2D systems, dominating over dimensions (radius r, thickness t). This study formulizes the effects from device physical parameters upon DR and sheds light on device design rules toward achieving high DR in 2D NEMS vibrating at radio and microwave frequencies

  2. High dynamic range vision sensor for automotive applications

    Science.gov (United States)

    Grenet, Eric; Gyger, Steve; Heim, Pascal; Heitger, Friedrich; Kaess, Francois; Nussbaum, Pascal; Ruedi, Pierre-Francois

    2005-02-01

    A 128 x 128 pixels, 120 dB vision sensor extracting at the pixel level the contrast magnitude and direction of local image features is used to implement a lane tracking system. The contrast representation (relative change of illumination) delivered by the sensor is independent of the illumination level. Together with the high dynamic range of the sensor, it ensures a very stable image feature representation even with high spatial and temporal inhomogeneities of the illumination. Dispatching off chip image feature is done according to the contrast magnitude, prioritizing features with high contrast magnitude. This allows to reduce drastically the amount of data transmitted out of the chip, hence the processing power required for subsequent processing stages. To compensate for the low fill factor (9%) of the sensor, micro-lenses have been deposited which increase the sensitivity by a factor of 5, corresponding to an equivalent of 2000 ASA. An algorithm exploiting the contrast representation output by the vision sensor has been developed to estimate the position of a vehicle relative to the road markings. The algorithm first detects the road markings based on the contrast direction map. Then, it performs quadratic fits on selected kernel of 3 by 3 pixels to achieve sub-pixel accuracy on the estimation of the lane marking positions. The resulting precision on the estimation of the vehicle lateral position is 1 cm. The algorithm performs efficiently under a wide variety of environmental conditions, including night and rainy conditions.

  3. Infrared Lunar Laser Ranging at Calern : Impact on Lunar Dynamics

    Science.gov (United States)

    Viswanathan, Vishnu; Fienga, Agnes; Manche, Herve; Gastineau, Mickael; Courde, Clement; Torre, Jean Marie; Exertier, Pierre; Laskar, Jacques

    2017-04-01

    Introduction: Since 2015, in addition to the traditional green (532nm), infrared (1064nm) has been the preferred wavelength for lunar laser ranging at the Calern lunar laser ranging (LLR) site in France. Due to the better atmospheric transmission of IR with respect to Green, nearly 3 times the number of normal points have been obtained in IR than in Green [1]. Dataset: In our study, in addition to the historical data obtained from various other LLR sites, we include the recent IR normal points obtained from Calern over the 1 year time span (2015-2016), constituting about 4.2% of data spread over 46 years of LLR. Near even distribution of data provided by IR on both the spatial and temporal domain, helps us to improve constraints on the internal structure of the Moon modeled within the planetary ephemeris : INPOP [2]. Data reduction: IERS recommended models have been used in the data reduction software GINS (GRGS,CNES) [3]. Constraints provided by GRAIL [4], on the Lunar gravitational potential and Love numbers have been taken into account in the least-square fit procedure. Earth orientation parameters from KEOF series have been used as per a recent study [5]. Results: New estimates on the dynamical parameters of the lunar core will be presented. Acknowledgements: We thank the lunar laser ranging observers at Observatoire de la Côte d'Azur, France, McDonald Observatory, Texas, Haleakala Observatory, Hawaii, and Apache Point Observatory in New Mexico for providing LLR observations that made this study possible. The research described in this abstract was carried out at Geoazur-CNRS, France, as a part of a PhD thesis funded by Observatoire de Paris and French Ministry of Education and Research. References: [1] Clement C. et al. (2016) submitted to A&A [2] Fienga A. et al. (2015) Celest Mech Dyn Astr, 123: 325. doi:10.1007/s10569-015-9639-y [3] Viswanathan V. et al. (2015) EGU, Abstract 18, 13995 [4] Konopliv A. S. et al. (2013) J. Geophys. Res. Planets, 118, 1415

  4. The effect of acquisition interval and spatial resolution on dynamic cardiac imaging with a stationary SPECT camera

    International Nuclear Information System (INIS)

    Roberts, J; Maddula, R; Clackdoyle, R; DiBella, E; Fu, Z

    2007-01-01

    The current SPECT scanning paradigm that acquires images by slow rotation of multiple detectors in body-contoured orbits around the patient is not suited to the rapid collection of tomographically complete data. During rapid image acquisition, mechanical and patient safety constraints limit the detector orbit to circular paths at increased distances from the patient, resulting in decreased spatial resolution. We consider a novel dynamic rotating slant-hole (DyRoSH) SPECT camera that can collect full tomographic data every 2 s, employing three stationary detectors mounted with slant-hole collimators that rotate at 30 rpm. Because the detectors are stationary, they can be placed much closer to the patient than is possible with conventional SPECT systems. We propose that the decoupling of the detector position from the mechanics of rapid image acquisition offers an additional degree of freedom which can be used to improve accuracy in measured kinetic parameter estimates. With simulations and list-mode reconstructions, we consider the effects of different acquisition intervals on dynamic cardiac imaging, comparing a conventional three detector SPECT system with the proposed DyRoSH SPECT system. Kinetic parameters of a two-compartment model of myocardial perfusion for technetium-99m-teboroxime were estimated. When compared to a conventional SPECT scanner for the same acquisition periods, the proposed DyRoSH system shows equivalent or reduced bias or standard deviation values for the kinetic parameter estimates. The DyRoSH camera with a 2 s acquisition period does not show any improvement compared to a DyRoSH camera with a 10 s acquisition period

  5. The effect of acquisition interval and spatial resolution on dynamic cardiac imaging with a stationary SPECT camera

    Science.gov (United States)

    Roberts, J.; Maddula, R.; Clackdoyle, R.; Di Bella, E.; Fu, Z.

    2007-08-01

    The current SPECT scanning paradigm that acquires images by slow rotation of multiple detectors in body-contoured orbits around the patient is not suited to the rapid collection of tomographically complete data. During rapid image acquisition, mechanical and patient safety constraints limit the detector orbit to circular paths at increased distances from the patient, resulting in decreased spatial resolution. We consider a novel dynamic rotating slant-hole (DyRoSH) SPECT camera that can collect full tomographic data every 2 s, employing three stationary detectors mounted with slant-hole collimators that rotate at 30 rpm. Because the detectors are stationary, they can be placed much closer to the patient than is possible with conventional SPECT systems. We propose that the decoupling of the detector position from the mechanics of rapid image acquisition offers an additional degree of freedom which can be used to improve accuracy in measured kinetic parameter estimates. With simulations and list-mode reconstructions, we consider the effects of different acquisition intervals on dynamic cardiac imaging, comparing a conventional three detector SPECT system with the proposed DyRoSH SPECT system. Kinetic parameters of a two-compartment model of myocardial perfusion for technetium-99m-teboroxime were estimated. When compared to a conventional SPECT scanner for the same acquisition periods, the proposed DyRoSH system shows equivalent or reduced bias or standard deviation values for the kinetic parameter estimates. The DyRoSH camera with a 2 s acquisition period does not show any improvement compared to a DyRoSH camera with a 10 s acquisition period.

  6. Scintillating camera

    International Nuclear Information System (INIS)

    Vlasbloem, H.

    1976-01-01

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

  7. Multi-camera and structured-light vision system (MSVS) for dynamic high-accuracy 3D measurements of railway tunnels.

    Science.gov (United States)

    Zhan, Dong; Yu, Long; Xiao, Jian; Chen, Tanglong

    2015-04-14

    Railway tunnel 3D clearance inspection is critical to guaranteeing railway operation safety. However, it is a challenge to inspect railway tunnel 3D clearance using a vision system, because both the spatial range and field of view (FOV) of such measurements are quite large. This paper summarizes our work on dynamic railway tunnel 3D clearance inspection based on a multi-camera and structured-light vision system (MSVS). First, the configuration of the MSVS is described. Then, the global calibration for the MSVS is discussed in detail. The onboard vision system is mounted on a dedicated vehicle and is expected to suffer from multiple degrees of freedom vibrations brought about by the running vehicle. Any small vibration can result in substantial measurement errors. In order to overcome this problem, a vehicle motion deviation rectifying method is investigated. Experiments using the vision inspection system are conducted with satisfactory online measurement results.

  8. Multi-Camera and Structured-Light Vision System (MSVS for Dynamic High-Accuracy 3D Measurements of Railway Tunnels

    Directory of Open Access Journals (Sweden)

    Dong Zhan

    2015-04-01

    Full Text Available Railway tunnel 3D clearance inspection is critical to guaranteeing railway operation safety. However, it is a challenge to inspect railway tunnel 3D clearance using a vision system, because both the spatial range and field of view (FOV of such measurements are quite large. This paper summarizes our work on dynamic railway tunnel 3D clearance inspection based on a multi-camera and structured-light vision system (MSVS. First, the configuration of the MSVS is described. Then, the global calibration for the MSVS is discussed in detail. The onboard vision system is mounted on a dedicated vehicle and is expected to suffer from multiple degrees of freedom vibrations brought about by the running vehicle. Any small vibration can result in substantial measurement errors. In order to overcome this problem, a vehicle motion deviation rectifying method is investigated. Experiments using the vision inspection system are conducted with satisfactory online measurement results.

  9. Imaging of radiocesium uptake dynamics in a plant body using a newly developed high-resolution gamma camera for radiocesium

    Energy Technology Data Exchange (ETDEWEB)

    Kawachi, Naoki; Yin, Yong-Gen; Suzui, Nobuo; Ishii, Satomi; Fujimaki, Shu [Radiotracer Imaging Gr., Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Yoshihara, Toshihiro [Plant Molecular Biology, Laboratory of Environmental Science, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba 270-1194 (Japan); Watabe, Hiroshi [Cyclotron and Radioisotope Center (CYRIC), Tohoku University, 6-3Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578 (Japan); Yamamoto, Seiichi [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya 461-8673 (Japan)

    2014-07-01

    Vast agricultural and forest areas around the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station in Japan were contaminated with radiocesium (Cs-134 and Cs-137) after the accident following the earthquake and tsunami in March 2011. A variety of agricultural studies, such as fertilizer management and plant breeding, have been undertaken intensively for reduction of radiocesium uptake in crops, or, enhancement of uptake in phyto-remediation. In this study, we newly developed a gamma camera specific for plant nutritional research, and performed quantitative analyses on uptake and partitioning of radiocesium in intact plant bodies. In general, gamma camera is a common technology in medical imaging, but it is not applicable to high-energy gamma rays such as emissions from Cs-137 (662 keV). Therefore, we designed our new gamma camera to prevent the penetration and scattering of the high-energy gamma rays. A single-crystal scintillator, Ce-doped Gd{sub 3}Al{sub 2}Ga{sub 3}O{sub 12} (Ce:GAGG), was employed, which has a relatively high density, a large light output, no natural radioactivity and no hygroscopicity. A 44 x 44 matrix of the Ce:GAGG pixels, with dimensions of 0.85 mm x 0.85 mm x 10 mm for each pixel, was coupled to a high-quantum efficiency position sensitive photomultiplier tube. This gamma detector unit was encased in a 20-mm-thick tungsten container with a tungsten pinhole collimator on the front. By using this gamma camera, soybean plants (Glycine max), grown in hydroponic solutions and fed with 1-2 MBq of Cs-137, were imaged for 6.5 days in maximum to investigate and visualize the uptake dynamics into/within the areal part. As a result, radiocesium gradually appeared in the shoot several hours after feeding of Cs-137, and then accumulated intensively in the maturing pods and seeds in a characteristic pattern. Our results also demonstrated that this gamma-camera method enables quantitative evaluation of plant ability to absorb, transport

  10. Population dynamics of sugar maple through the southern portion of its range: implications for range migration

    Science.gov (United States)

    Justin L. Hart; Christopher M. Oswalt; Craig M. Turberville

    2014-01-01

    The range of sugar maple (Acer saccharum Marsh.) is expected to shift northward in accord with changing climate. However, a pattern of increased sugar maple abundance has been reported from sites throughout the eastern US. The goal of our study was to examine the stability of the sugar maple southern range boundary by analyzing its demography through...

  11. Multi-sensors multi-baseline mapping system for mobile robot using stereovision camera and laser-range device

    Directory of Open Access Journals (Sweden)

    Mohammed Faisal

    2016-06-01

    Full Text Available Countless applications today are using mobile robots, including autonomous navigation, security patrolling, housework, search-and-rescue operations, material handling, manufacturing, and automated transportation systems. Regardless of the application, a mobile robot must use a robust autonomous navigation system. Autonomous navigation remains one of the primary challenges in the mobile-robot industry; many control algorithms and techniques have been recently developed that aim to overcome this challenge. Among autonomous navigation methods, vision-based systems have been growing in recent years due to rapid gains in computational power and the reliability of visual sensors. The primary focus of research into vision-based navigation is to allow a mobile robot to navigate in an unstructured environment without collision. In recent years, several researchers have looked at methods for setting up autonomous mobile robots for navigational tasks. Among these methods, stereovision-based navigation is a promising approach for reliable and efficient navigation. In this article, we create and develop a novel mapping system for a robust autonomous navigation system. The main contribution of this article is the fuse of the multi-baseline stereovision (narrow and wide baselines and laser-range reading data to enhance the accuracy of the point cloud, to reduce the ambiguity of correspondence matching, and to extend the field of view of the proposed mapping system to 180°. Another contribution is the pruning the region of interest of the three-dimensional point clouds to reduce the computational burden involved in the stereo process. Therefore, we called the proposed system multi-sensors multi-baseline mapping system. The experimental results illustrate the robustness and accuracy of the proposed system.

  12. Toluene model for molecular dynamics simulations in the ranges 298

    NARCIS (Netherlands)

    Fioroni, M.; Vogt, D.

    2004-01-01

    An all-atom model for toluene is presented in the framework of classical molecular dynamics (MD). The model has been parametrized under the GROMOS96 force field to reproduce the physicochemical properties of the neat liquid. Four new atom types have been introduced, distinguishing between carbons

  13. A high resolution large dynamic range TDC circuit implementation

    International Nuclear Information System (INIS)

    Lei Wuhu; Liu Songqiu; Ye Weiguo; Han Hui; Li Pengyu

    2003-01-01

    Time measurement technology is usually used in nuclear experimentation. There are many methods of time measurement. The implementation method of Time to Digital Conversion (TDC) by means of electronic is a classical technology. The range and resolution of TDC is different according with different usage. A wide range and high resolution TDC circuit, including its theory and implementation way, is introduced in this paper. The test result is also given. (authors)

  14. A high resolution large dynamic range TDC circuit implementation

    International Nuclear Information System (INIS)

    Lei Wuhu; Liu Songqiu; Li Pengyu; Han Hui; Ye Yanlin

    2005-01-01

    Time measurement technology is usually used in nuclear experimentation. There are many methods of time measurement. The implementation method of Time to Digital Conversion (TDC) by means of electronics is a classical technology. The range and resolution of TDC is different according with different usage. A wide range and high resolution TDC circuit, including its theory and implementation way, is introduced in this paper. The test result is also given. (authors)

  15. Long range personalized cancer treatment strategies incorporating evolutionary dynamics.

    Science.gov (United States)

    Yeang, Chen-Hsiang; Beckman, Robert A

    2016-10-22

    Current cancer precision medicine strategies match therapies to static consensus molecular properties of an individual's cancer, thus determining the next therapeutic maneuver. These strategies typically maintain a constant treatment while the cancer is not worsening. However, cancers feature complicated sub-clonal structure and dynamic evolution. We have recently shown, in a comprehensive simulation of two non-cross resistant therapies across a broad parameter space representing realistic tumors, that substantial improvement in cure rates and median survival can be obtained utilizing dynamic precision medicine strategies. These dynamic strategies explicitly consider intratumoral heterogeneity and evolutionary dynamics, including predicted future drug resistance states, and reevaluate optimal therapy every 45 days. However, the optimization is performed in single 45 day steps ("single-step optimization"). Herein we evaluate analogous strategies that think multiple therapeutic maneuvers ahead, considering potential outcomes at 5 steps ahead ("multi-step optimization") or 40 steps ahead ("adaptive long term optimization (ALTO)") when recommending the optimal therapy in each 45 day block, in simulations involving both 2 and 3 non-cross resistant therapies. We also evaluate an ALTO approach for situations where simultaneous combination therapy is not feasible ("Adaptive long term optimization: serial monotherapy only (ALTO-SMO)"). Simulations utilize populations of 764,000 and 1,700,000 virtual patients for 2 and 3 drug cases, respectively. Each virtual patient represents a unique clinical presentation including sizes of major and minor tumor subclones, growth rates, evolution rates, and drug sensitivities. While multi-step optimization and ALTO provide no significant average survival benefit, cure rates are significantly increased by ALTO. Furthermore, in the subset of individual virtual patients demonstrating clinically significant difference in outcome between

  16. On (dynamic) range minimum queries in external memory

    DEFF Research Database (Denmark)

    Arge, L.; Fischer, Johannes; Sanders, Peter

    2013-01-01

    We study the one-dimensional range minimum query (RMQ) problem in the external memory model. We provide the first space-optimal solution to the batched static version of the problem. On an instance with N elements and Q queries, our solution takes Θ(sort(N + Q)) = Θ( N+QB log M /B N+QB ) I...

  17. Dynamic range broadening for photomultipliers in kinetic spectrophotometry

    International Nuclear Information System (INIS)

    Rumas, V.K.

    1983-01-01

    The circuit of switching on a photomultiplier with prestage modulation developed for kinetic spectrophotometry purposes is described. Distinguishing features of the scheme are wide range of control pulse duration (40 nc - 2.5 mc) and direct transistor photostart by laser light pulse. In the case of PM prestage modulation for the second dynode modulation depth attains 400 while PM opening time constitutes 40 nc

  18. The dynamics of biogeographic ranges in the deep sea.

    Science.gov (United States)

    McClain, Craig R; Hardy, Sarah Mincks

    2010-12-07

    Anthropogenic disturbances such as fishing, mining, oil drilling, bioprospecting, warming, and acidification in the deep sea are increasing, yet generalities about deep-sea biogeography remain elusive. Owing to the lack of perceived environmental variability and geographical barriers, ranges of deep-sea species were traditionally assumed to be exceedingly large. In contrast, seamount and chemosynthetic habitats with reported high endemicity challenge the broad applicability of a single biogeographic paradigm for the deep sea. New research benefiting from higher resolution sampling, molecular methods and public databases can now more rigorously examine dispersal distances and species ranges on the vast ocean floor. Here, we explore the major outstanding questions in deep-sea biogeography. Based on current evidence, many taxa appear broadly distributed across the deep sea, a pattern replicated in both the abyssal plains and specialized environments such as hydrothermal vents. Cold waters may slow larval metabolism and development augmenting the great intrinsic ability for dispersal among many deep-sea species. Currents, environmental shifts, and topography can prove to be dispersal barriers but are often semipermeable. Evidence of historical events such as points of faunal origin and climatic fluctuations are also evident in contemporary biogeographic ranges. Continued synthetic analysis, database construction, theoretical advancement and field sampling will be required to further refine hypotheses regarding deep-sea biogeography.

  19. Nuclear dynamics with the (finite range) Gogny force: flow effects

    International Nuclear Information System (INIS)

    Sebille, F.; Royer, G.; Schuck, P.; Gregoire, C.

    1988-01-01

    We introduce for the first time the effective finite range interaction of Gogny in the semi-classical description of heavy ion reactions based on the Landau-Vlasov equation. The characteristics of the flow for heavy ion collisions are studied as functions of the incident energy, the impact parameter and the mass number. The momentum dependence in the mean field together with the non linearities in the collision kernel decrease the flow in contradiction with other calculations; the origins of this discrepancy are studied in details

  20. High-dynamic-range microscope imaging based on exposure bracketing in full-field optical coherence tomography.

    Science.gov (United States)

    Leong-Hoi, Audrey; Montgomery, Paul C; Serio, Bruno; Twardowski, Patrice; Uhring, Wilfried

    2016-04-01

    By applying the proposed high-dynamic-range (HDR) technique based on exposure bracketing, we demonstrate a meaningful reduction in the spatial noise in image frames acquired with a CCD camera so as to improve the fringe contrast in full-field optical coherence tomography (FF-OCT). This new signal processing method thus allows improved probing within transparent or semitransparent samples. The proposed method is demonstrated on 3 μm thick transparent polymer films of Mylar, which, due to their transparency, produce low contrast fringe patterns in white-light interference microscopy. High-resolution tomographic analysis is performed using the technique. After performing appropriate signal processing, resulting XZ sections are observed. Submicrometer-sized defects can be lost in the noise that is present in the CCD images. With the proposed method, we show that by increasing the signal-to-noise ratio of the images, submicrometer-sized defect structures can thus be detected.

  1. Presence capture cameras - a new challenge to the image quality

    Science.gov (United States)

    Peltoketo, Veli-Tapani

    2016-04-01

    Commercial presence capture cameras are coming to the markets and a new era of visual entertainment starts to get its shape. Since the true presence capturing is still a very new technology, the real technical solutions are just passed a prototyping phase and they vary a lot. Presence capture cameras have still the same quality issues to tackle as previous phases of digital imaging but also numerous new ones. This work concentrates to the quality challenges of presence capture cameras. A camera system which can record 3D audio-visual reality as it is has to have several camera modules, several microphones and especially technology which can synchronize output of several sources to a seamless and smooth virtual reality experience. Several traditional quality features are still valid in presence capture cameras. Features like color fidelity, noise removal, resolution and dynamic range create the base of virtual reality stream quality. However, co-operation of several cameras brings a new dimension for these quality factors. Also new quality features can be validated. For example, how the camera streams should be stitched together with 3D experience without noticeable errors and how to validate the stitching? The work describes quality factors which are still valid in the presence capture cameras and defines the importance of those. Moreover, new challenges of presence capture cameras are investigated in image and video quality point of view. The work contains considerations how well current measurement methods can be used in presence capture cameras.

  2. Optimized lighting method of applying shaped-function signal for increasing the dynamic range of LED-multispectral imaging system

    Science.gov (United States)

    Yang, Xue; Hu, Yajia; Li, Gang; Lin, Ling

    2018-02-01

    This paper proposes an optimized lighting method of applying a shaped-function signal for increasing the dynamic range of light emitting diode (LED)-multispectral imaging system. The optimized lighting method is based on the linear response zone of the analog-to-digital conversion (ADC) and the spectral response of the camera. The auxiliary light at a higher sensitivity-camera area is introduced to increase the A/D quantization levels that are within the linear response zone of ADC and improve the signal-to-noise ratio. The active light is modulated by the shaped-function signal to improve the gray-scale resolution of the image. And the auxiliary light is modulated by the constant intensity signal, which is easy to acquire the images under the active light irradiation. The least square method is employed to precisely extract the desired images. One wavelength in multispectral imaging based on LED illumination was taken as an example. It has been proven by experiments that the gray-scale resolution and the accuracy of information of the images acquired by the proposed method were both significantly improved. The optimum method opens up avenues for the hyperspectral imaging of biological tissue.

  3. Automated selection of areas of interest in dynamic studies and camera-cinematograpy of the heart

    International Nuclear Information System (INIS)

    Bitter, F.; Adam, W.E.; Kampmann, H.; Meyer, G.; Weller, R.

    1975-01-01

    Progress is reported in heart investigations using the first transit principle and the steady-state procedure for radionuclide scanning. Progress in the first transit principle relies on automated selection of areas of interest. A procedure has been developed which automatically performs the evaluation of the areas corresponding to the right heart, the lungs, and the left heart. A different procedure has been built up for dynamic lung studies with Xe-133 (Radiospirometry), which principally can be applied to any other organ investigation. R-wave time averaged procedures of the heart in steady state can be performed in direct or indirect manner. A direct procedure is described that leads eventually to a cinematographic presentation of the heart kinetics on the computer display. The analysis yields an exact outline of heart ventricles and auricles as prerequisite for determination of ejection fractions and clinically relevant data of the heart function

  4. Probing the role of long-range interactions in the dynamics of a long-range Kitaev chain

    Science.gov (United States)

    Dutta, Anirban; Dutta, Amit

    2017-09-01

    We study the role of long-range interactions (more precisely, the long-range superconducting gap term) on the nonequilibrium dynamics considering a long-range p -wave superconducting chain in which the superconducting term decays with distance between two sites in a power-law fashion characterized by an exponent α . We show that the Kibble-Zurek scaling exponent, dictating the power-law decay of the defect density in the final state reached following a slow (in comparison to the time scale associated with the minimum gap in the spectrum of the Hamiltonian) quenching of the chemical potential μ across a quantum critical point, depends nontrivially on the exponent α as long as α 2 , we find that the exponent saturates to the corresponding well-known value of 1 /2 expected for the short-range model. Furthermore, studying the dynamical quantum phase transitions manifested in the nonanalyticities in the rate function of the return possibility I (t ) in subsequent temporal evolution following a sudden change in μ , we show the existence of a new region; in this region, we find three instants of cusp singularities in I (t ) associated with a single sector of Fisher zeros. Notably, the width of this region shrinks as α increases and vanishes in the limit α →2 , indicating that this special region is an artifact of the long-range nature of the Hamiltonian.

  5. High speed, wide dynamic range analog signal processing for avalanche photodiode

    CERN Document Server

    Walder, J P; Pangaud, P

    2000-01-01

    A wide dynamic range multi-gain analog transimpedance amplifier integrated circuit has been developed for avalanche photodiode signal processing. The 96 dB input dynamic range is divided into four ranges of 12-bits each in order to provide 40 MHz analog sampled data to a 12-bits ADC. This concept which has been integrated in both BiCMOS and full complementary bipolar technology along with fitted design techniques will be presented.

  6. High speed, wide dynamic range analog signal processing for avalanche photodiode

    International Nuclear Information System (INIS)

    Walder, J.P.; El Mamouni, Houmani; Pangaud, Patrick

    2000-01-01

    A wide dynamic range multi-gain analog transimpedance amplifier integrated circuit has been developed for avalanche photodiode signal processing. The 96 dB input dynamic range is divided into four ranges of 12-bits each in order to provide 40 MHz analog sampled data to a 12-bits ADC. This concept which has been integrated in both BiCMOS and full complementary bipolar technology along with fitted design techniques will be presented

  7. High speed, wide dynamic range analog signal processing for avalanche photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Walder, J.P. E-mail: walder@in2p3.fr; El Mamouni, Houmani; Pangaud, Patrick

    2000-03-11

    A wide dynamic range multi-gain analog transimpedance amplifier integrated circuit has been developed for avalanche photodiode signal processing. The 96 dB input dynamic range is divided into four ranges of 12-bits each in order to provide 40 MHz analog sampled data to a 12-bits ADC. This concept which has been integrated in both BiCMOS and full complementary bipolar technology along with fitted design techniques will be presented.

  8. In-line process control for laser welding of titanium by high dynamic range ratio pyrometry and plasma spectroscopy

    Science.gov (United States)

    Lempe, B.; Taudt, C.; Baselt, T.; Rudek, F.; Maschke, R.; Basan, F.; Hartmann, P.

    2014-02-01

    The production of complex titanium components for various industries using laser welding processes has received growing attention in recent years. It is important to know whether the result of the cohesive joint meets the quality requirements of standardization and ultimately the customer requirements. Erroneous weld seams can have fatal consequences especially in the field of car manufacturing and medicine technology. To meet these requirements, a real-time process control system has been developed which determines the welding quality through a locally resolved temperature profile. By analyzing the resulting weld plasma received data is used to verify the stability of the laser welding process. The determination of the temperature profile is done by the detection of the emitted electromagnetic radiation from the material in a range of 500 nm to 1100 nm. As detectors, special high dynamic range CMOS cameras are used. As the emissivity of titanium depends on the wavelength, the surface and the angle of radiation, measuring the temperature is a problem. To solve these a special pyrometer setting with two cameras is used. That enables the compensation of these effects by calculating the difference between the respective pixels on simultaneously recorded images. Two spectral regions with the same emissivity are detected. Therefore the degree of emission and surface effects are compensated and canceled out of the calculation. Using the spatially resolved temperature distribution the weld geometry can be determined and the laser process can be controlled. The active readjustment of parameters such as laser power, feed rate and inert gas injection increases the quality of the welding process and decreases the number of defective goods.

  9. Time-resolved imaging of prompt-gamma rays for proton range verification using a knife-edge slit camera based on digital photon counters

    Science.gov (United States)

    Cambraia Lopes, Patricia; Clementel, Enrico; Crespo, Paulo; Henrotin, Sebastien; Huizenga, Jan; Janssens, Guillaume; Parodi, Katia; Prieels, Damien; Roellinghoff, Frauke; Smeets, Julien; Stichelbaut, Frederic; Schaart, Dennis R.

    2015-08-01

    Proton range monitoring may facilitate online adaptive proton therapy and improve treatment outcomes. Imaging of proton-induced prompt gamma (PG) rays using a knife-edge slit collimator is currently under investigation as a potential tool for real-time proton range monitoring. A major challenge in collimated PG imaging is the suppression of neutron-induced background counts. In this work, we present an initial performance test of two knife-edge slit camera prototypes based on arrays of digital photon counters (DPCs). PG profiles emitted from a PMMA target upon irradiation with a 160 MeV proton pencil beams (about 6.5   ×   109 protons delivered in total) were measured using detector modules equipped with four DPC arrays coupled to BGO or LYSO : Ce crystal matrices. The knife-edge slit collimator and detector module were placed at 15 cm and 30 cm from the beam axis, respectively, in all cases. The use of LYSO : Ce enabled time-of-flight (TOF) rejection of background events, by synchronizing the DPC readout electronics with the 106 MHz radiofrequency signal of the cyclotron. The signal-to-background (S/B) ratio of 1.6 obtained with a 1.5 ns TOF window and a 3 MeV-7 MeV energy window was about 3 times higher than that obtained with the same detector module without TOF discrimination and 2 times higher than the S/B ratio obtained with the BGO module. Even 1 mm shifts of the Bragg peak position translated into clear and consistent shifts of the PG profile if TOF discrimination was applied, for a total number of protons as low as about 6.5   ×   108 and a detector surface of 6.6 cm  ×  6.6 cm.

  10. Gamma camera

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  11. Gamma camera

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  12. Picosecond camera

    International Nuclear Information System (INIS)

    Decroisette, Michel

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

  13. Nonmedical applications of a positron camera

    International Nuclear Information System (INIS)

    Hawkesworth, M.R.; Parker, D.J.; Fowles, P.; Crilly, J.F.; Jefferies, N.L.; Jonkers, G.

    1991-01-01

    The positron camera in the School on Physics and Space Research, University of Birmingham, is based on position-sensitive multiwire γ-ray detectors developed at the Rutherford Appleton Laboratory. The current characteristics of the camera are discussed with particular reference to its suitability for flow mapping in industrial subjects. The techniques developed for studying the dynamics of processes with time scales ranging from milliseconds to days are described, and examples of recent results from a variety of industrial applications are presented. (orig.)

  14. How interactions between animal movement and landscape processes modify range dynamics and extinction risk

    Science.gov (United States)

    Range dynamics models now incorporate many of the mechanisms and interactions that drive species distributions. However, connectivity continues to be studied using overly simple distance-based dispersal models with little consideration of how the individual behavior of dispersin...

  15. Dynamic range enhancement and amplitude regeneration in single pump fibre optic parametric amplifiers using DPSK modulation

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Lorenzen, Michael Rodas; Seoane, Jorge

    2008-01-01

    Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain.......Input power dynamic range enhancement and amplitude regeneration of highly distorted signals are demonstrated experimentally for 40 Gbit/s RZ-DPSK in a single-pump fibre parametric amplifier with 22 dB smallsignal gain....

  16. Extraordinary tunable dynamic range of electrochemical aptasensor for accurate detection of ochratoxin A in food samples

    Directory of Open Access Journals (Sweden)

    Lin Cheng

    2017-06-01

    Full Text Available We report the design of a sensitive, electrochemical aptasensor for detection of ochratoxin A (OTA with an extraordinary tunable dynamic sensing range. This electrochemical aptasensor is constructed based on the target induced aptamer-folding detection mechanism and the recognition between OTA and its aptamers results in the conformational change of the aptamer probe and thus signal changes for measurement. The dynamic sensing range of the electrochemical aptasensor is successfully tuned by introduction of free assistant aptamer probes in the sensing system. Our electrochemical aptasensor shows an extraordinary dynamic sensing range of 11-order magnitude of OTA concentration from 10−8 to 102 ng/g. Of great significance, the signal response in all OTA concentration ranges is at the same current scale, demonstrating that our sensing protocol in this research could be applied for accurate detections of OTA in a broad range without using any complicated treatment of signal amplification. Finally, OTA spiked red wine and maize samples in different dynamic sensing ranges are determined with the electrochemical aptasensor under optimized sensing conditions. This tuning strategy of dynamic sensing range may offer a promising platform for electrochemical aptasensor optimizations in practical applications.

  17. High Dynamic Velocity Range Particle Image Velocimetry Using Multiple Pulse Separation Imaging

    Directory of Open Access Journals (Sweden)

    Tadhg S. O’Donovan

    2010-12-01

    Full Text Available The dynamic velocity range of particle image velocimetry (PIV is determined by the maximum and minimum resolvable particle displacement. Various techniques have extended the dynamic range, however flows with a wide velocity range (e.g., impinging jets still challenge PIV algorithms. A new technique is presented to increase the dynamic velocity range by over an order of magnitude. The multiple pulse separation (MPS technique (i records series of double-frame exposures with different pulse separations, (ii processes the fields using conventional multi-grid algorithms, and (iii yields a composite velocity field with a locally optimized pulse separation. A robust criterion determines the local optimum pulse separation, accounting for correlation strength and measurement uncertainty. Validation experiments are performed in an impinging jet flow, using laser-Doppler velocimetry as reference measurement. The precision of mean flow and turbulence quantities is significantly improved compared to conventional PIV, due to the increase in dynamic range. In a wide range of applications, MPS PIV is a robust approach to increase the dynamic velocity range without restricting the vector evaluation methods.

  18. High dynamic velocity range particle image velocimetry using multiple pulse separation imaging.

    Science.gov (United States)

    Persoons, Tim; O'Donovan, Tadhg S

    2011-01-01

    The dynamic velocity range of particle image velocimetry (PIV) is determined by the maximum and minimum resolvable particle displacement. Various techniques have extended the dynamic range, however flows with a wide velocity range (e.g., impinging jets) still challenge PIV algorithms. A new technique is presented to increase the dynamic velocity range by over an order of magnitude. The multiple pulse separation (MPS) technique (i) records series of double-frame exposures with different pulse separations, (ii) processes the fields using conventional multi-grid algorithms, and (iii) yields a composite velocity field with a locally optimized pulse separation. A robust criterion determines the local optimum pulse separation, accounting for correlation strength and measurement uncertainty. Validation experiments are performed in an impinging jet flow, using laser-Doppler velocimetry as reference measurement. The precision of mean flow and turbulence quantities is significantly improved compared to conventional PIV, due to the increase in dynamic range. In a wide range of applications, MPS PIV is a robust approach to increase the dynamic velocity range without restricting the vector evaluation methods.

  19. Systems approach to the design of the CCD sensors and camera electronics for the AIA and HMI instruments on solar dynamics observatory

    Science.gov (United States)

    Waltham, N.; Beardsley, S.; Clapp, M.; Lang, J.; Jerram, P.; Pool, P.; Auker, G.; Morris, D.; Duncan, D.

    2017-11-01

    Solar Dynamics Observatory (SDO) is imaging the Sun in many wavelengths near simultaneously and with a resolution ten times higher than the average high-definition television. In this paper we describe our innovative systems approach to the design of the CCD cameras for two of SDO's remote sensing instruments, the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI). Both instruments share use of a custom-designed 16 million pixel science-grade CCD and common camera readout electronics. A prime requirement was for the CCD to operate with significantly lower drive voltages than before, motivated by our wish to simplify the design of the camera readout electronics. Here, the challenge lies in the design of circuitry to drive the CCD's highly capacitive electrodes and to digitize its analogue video output signal with low noise and to high precision. The challenge is greatly exacerbated when forced to work with only fully space-qualified, radiation-tolerant components. We describe our systems approach to the design of the AIA and HMI CCD and camera electronics, and the engineering solutions that enabled us to comply with both mission and instrument science requirements.

  20. Multi-input wide dynamic range ADC system for use with nuclear detectors

    Energy Technology Data Exchange (ETDEWEB)

    Austin, R W [National Aeronautics and Space Administration, Huntsville, Ala. (USA). George C. Marshall Space Flight Center

    1976-04-15

    A wide dynamic range, eight input analog-to-digital converter system has been developed for use in nuclear experiments. The system consists of eight dual-range sample and hold modules, an eight input multiplexer, a ten-bit analog-to-digital converter, and the associated control logic.

  1. Gamma camera

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  2. Displacement and deformation measurement for large structures by camera network

    Science.gov (United States)

    Shang, Yang; Yu, Qifeng; Yang, Zhen; Xu, Zhiqiang; Zhang, Xiaohu

    2014-03-01

    A displacement and deformation measurement method for large structures by a series-parallel connection camera network is presented. By taking the dynamic monitoring of a large-scale crane in lifting operation as an example, a series-parallel connection camera network is designed, and the displacement and deformation measurement method by using this series-parallel connection camera network is studied. The movement range of the crane body is small, and that of the crane arm is large. The displacement of the crane body, the displacement of the crane arm relative to the body and the deformation of the arm are measured. Compared with a pure series or parallel connection camera network, the designed series-parallel connection camera network can be used to measure not only the movement and displacement of a large structure but also the relative movement and deformation of some interesting parts of the large structure by a relatively simple optical measurement system.

  3. Regulation of Cortical Dynamic Range by Background Synaptic Noise and Feedforward Inhibition.

    Science.gov (United States)

    Khubieh, Ayah; Ratté, Stéphanie; Lankarany, Milad; Prescott, Steven A

    2016-08-01

    The cortex encodes a broad range of inputs. This breadth of operation requires sensitivity to weak inputs yet non-saturating responses to strong inputs. If individual pyramidal neurons were to have a narrow dynamic range, as previously claimed, then staggered all-or-none recruitment of those neurons would be necessary for the population to achieve a broad dynamic range. Contrary to this explanation, we show here through dynamic clamp experiments in vitro and computer simulations that pyramidal neurons have a broad dynamic range under the noisy conditions that exist in the intact brain due to background synaptic input. Feedforward inhibition capitalizes on those noise effects to control neuronal gain and thereby regulates the population dynamic range. Importantly, noise allows neurons to be recruited gradually and occludes the staggered recruitment previously attributed to heterogeneous excitation. Feedforward inhibition protects spike timing against the disruptive effects of noise, meaning noise can enable the gain control required for rate coding without compromising the precise spike timing required for temporal coding. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  4. A high dynamic range pulse counting detection system for mass spectrometry.

    Science.gov (United States)

    Collings, Bruce A; Dima, Martian D; Ivosev, Gordana; Zhong, Feng

    2014-01-30

    A high dynamic range pulse counting system has been developed that demonstrates an ability to operate at up to 2e8 counts per second (cps) on a triple quadrupole mass spectrometer. Previous pulse counting detection systems have typically been limited to about 1e7 cps at the upper end of the systems dynamic range. Modifications to the detection electronics and dead time correction algorithm are described in this paper. A high gain transimpedance amplifier is employed that allows a multi-channel electron multiplier to be operated at a significantly lower bias potential than in previous pulse counting systems. The system utilises a high-energy conversion dynode, a multi-channel electron multiplier, a high gain transimpedance amplifier, non-paralysing detection electronics and a modified dead time correction algorithm. Modification of the dead time correction algorithm is necessary due to a characteristic of the pulse counting electronics. A pulse counting detection system with the capability to count at ion arrival rates of up to 2e8 cps is described. This is shown to provide a linear dynamic range of nearly five orders of magnitude for a sample of aprazolam with concentrations ranging from 0.0006970 ng/mL to 3333 ng/mL while monitoring the m/z 309.1 → m/z 205.2 transition. This represents an upward extension of the detector's linear dynamic range of about two orders of magnitude. A new high dynamic range pulse counting system has been developed demonstrating the ability to operate at up to 2e8 cps on a triple quadrupole mass spectrometer. This provides an upward extension of the detector's linear dynamic range by about two orders of magnitude over previous pulse counting systems. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Angiocardiography with 99mTc-albumin bymass of gamma camera associated with examinations in the morphological and dynamic study of the congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Esposti, A D; Abbati, A

    1975-03-03

    A. Degli Esposti and A. Abbati: Computerised gamma-camera 99/sup m/ Tc-albumin angiocardiography in the morphological and dynamic examination of children with congenital heart disease. A number of cases in which computerised gamma-camera 99/sup m/ Tc-albumin angiocardiography was employed in children with congenital heart diseases are described. Comparison is made with the data obtained contrastographically, or during surgery or necropsy. The preliminary results, particularly in recently examined subjects, whose data were processed in a more efficient manner, point to the usefulness of the method. Though incapable of offering the same morphological precision as contrastography, it has the advantage of being absolute harmless and, above all, repeatable.

  6. Impacts of land cover data selection and trait parameterisation on dynamic modelling of species' range expansion.

    Directory of Open Access Journals (Sweden)

    Risto K Heikkinen

    Full Text Available Dynamic models for range expansion provide a promising tool for assessing species' capacity to respond to climate change by shifting their ranges to new areas. However, these models include a number of uncertainties which may affect how successfully they can be applied to climate change oriented conservation planning. We used RangeShifter, a novel dynamic and individual-based modelling platform, to study two potential sources of such uncertainties: the selection of land cover data and the parameterization of key life-history traits. As an example, we modelled the range expansion dynamics of two butterfly species, one habitat specialist (Maniola jurtina and one generalist (Issoria lathonia. Our results show that projections of total population size, number of occupied grid cells and the mean maximal latitudinal range shift were all clearly dependent on the choice made between using CORINE land cover data vs. using more detailed grassland data from three alternative national databases. Range expansion was also sensitive to the parameterization of the four considered life-history traits (magnitude and probability of long-distance dispersal events, population growth rate and carrying capacity, with carrying capacity and magnitude of long-distance dispersal showing the strongest effect. Our results highlight the sensitivity of dynamic species population models to the selection of existing land cover data and to uncertainty in the model parameters and indicate that these need to be carefully evaluated before the models are applied to conservation planning.

  7. Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics.

    Science.gov (United States)

    Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing

    2016-06-03

    In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends.

  8. Sorting method to extend the dynamic range of the Shack-Hartmann wave-front sensor

    International Nuclear Information System (INIS)

    Lee, Junwon; Shack, Roland V.; Descour, Michael R.

    2005-01-01

    We propose a simple and powerful algorithm to extend the dynamic range of a Shack-Hartmann wave-front sensor. In a conventional Shack-Hartmann wave-front sensor the dynamic range is limited by the f-number of a lenslet, because the focal spot is required to remain in the area confined by the single lenslet. The sorting method proposed here eliminates such a limitation and extends the dynamic range by tagging each spot in a special sequence. Since the sorting method is a simple algorithm that does not change the measurement configuration, there is no requirement for extra hardware, multiple measurements, or complicated algorithms. We not only present the theory and a calculation example of the sorting method but also actually implement measurement of a highly aberrated wave front from nonrotational symmetric optics

  9. Fast and robust wavelet-based dynamic range compression and contrast enhancement model with color restoration

    Science.gov (United States)

    Unaldi, Numan; Asari, Vijayan K.; Rahman, Zia-ur

    2009-05-01

    Recently we proposed a wavelet-based dynamic range compression algorithm to improve the visual quality of digital images captured from high dynamic range scenes with non-uniform lighting conditions. The fast image enhancement algorithm that provides dynamic range compression, while preserving the local contrast and tonal rendition, is also a good candidate for real time video processing applications. Although the colors of the enhanced images produced by the proposed algorithm are consistent with the colors of the original image, the proposed algorithm fails to produce color constant results for some "pathological" scenes that have very strong spectral characteristics in a single band. The linear color restoration process is the main reason for this drawback. Hence, a different approach is required for the final color restoration process. In this paper the latest version of the proposed algorithm, which deals with this issue is presented. The results obtained by applying the algorithm to numerous natural images show strong robustness and high image quality.

  10. Event-Based Color Segmentation With a High Dynamic Range Sensor

    Directory of Open Access Journals (Sweden)

    Alexandre Marcireau

    2018-04-01

    Full Text Available This paper introduces a color asynchronous neuromorphic event-based camera and a methodology to process color output from the device to perform color segmentation and tracking at the native temporal resolution of the sensor (down to one microsecond. Our color vision sensor prototype is a combination of three Asynchronous Time-based Image Sensors, sensitive to absolute color information. We devise a color processing algorithm leveraging this information. It is designed to be computationally cheap, thus showing how low level processing benefits from asynchronous acquisition and high temporal resolution data. The resulting color segmentation and tracking performance is assessed both with an indoor controlled scene and two outdoor uncontrolled scenes. The tracking's mean error to the ground truth for the objects of the outdoor scenes ranges from two to twenty pixels.

  11. A high speed, wide dynamic range digitizer circuit for photomultiplier tubes

    International Nuclear Information System (INIS)

    Yarema, R.J.; Foster, G.W.; Knickerbocker, K.; Sarraj, M.; Tschirhart, R.; Whitmore, J.; Zimmerman, T.; Lindgren, M.

    1995-01-01

    A circuit has been designed for digitizing PMT signals over a wide dynamic range (17-18 bits) with 8 bits of resolution at rates up to 53 MHz. Output from the circuit is in a floating point format with a 4 bit exponent and an 8 bit mantissa. The heart of the circuit is a full custom integrated circuit called the QIE (Charge Integrator and Encoder). The design of the QIE and associated circuitry reported here permits operation over a 17 bit dynamic range. Test results of a multirange device are presented for the first time. (orig.)

  12. Neutron cameras for ITER

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  13. Expanding the dynamic measurement range for polymeric nanoparticle pH sensors

    DEFF Research Database (Denmark)

    Sun, Honghao; Almdal, Kristoffer; Andresen, Thomas Lars

    2011-01-01

    Conventional optical nanoparticle pH sensors that are designed for ratiometric measurements in cells have been based on utilizing one sensor fluorophore and one reference fluorophore in each nanoparticle, which results in a relatively narrow dynamic measurement range. This results in substantial...

  14. Density matrix renormalization group with efficient dynamical electron correlation through range separation

    DEFF Research Database (Denmark)

    Hedegård, Erik D.; Knecht, Stefan; Kielberg, Jesper Skau

    2015-01-01

    We present a new hybrid multiconfigurational method based on the concept of range-separation that combines the density matrix renormalization group approach with density functional theory. This new method is designed for the simultaneous description of dynamical and static electroncorrelation...... effects in multiconfigurational electronic structure problems....

  15. High dynamic range isotope ratio measurements using an analog electron multiplier

    Czech Academy of Sciences Publication Activity Database

    Williams, P.; Lorinčík, Jan; Franzreb, K.; Herwig, R.

    2013-01-01

    Roč. 45, č. 1 (2013), s. 549-552 ISSN 0142-2421 R&D Projects: GA MŠk ME 894 Institutional support: RVO:67985882 Keywords : Isotope ratios * electron multiplier * dynamic range Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.393, year: 2013

  16. A low-power high dynamic range front-end ASIC for imaging calorimeters

    CERN Document Server

    Bagliesi, M G; Marrocchesi, P S; Meucci, M; Millucci, V; Morsani, F; Paoletti, R; Pilo, F; Scribano, A; Turini, N; Valle, G D

    2002-01-01

    High granularity calorimeters with shower imaging capabilities require dedicated front-end electronics. The ICON 4CH and VA4 PMT chip-set is suitable for very high dynamic range systems with strict noise requirements. The ICON 4CH is a 4 channel input, 12 channel output ASIC designed for use in a multi-anode photomultiplier system with very large dynamic range and low-noise requirements. Each of the four input signals to the ASIC is split equally into three branches by a current conveyor. Each of the three branches is scaled differently: 1:1, 1:8 and 1:80. The signal is read out by a 12 channel low noise/low power high dynamic range charge sensitive preamplifier-shaper circuit (VA4-PMT chip), with simultaneous sample- and-hold, multiplexed analog read-out, calibration facilities. Tests performed in our lab with a PMT are reported in terms of linearity, dynamic range and cross-talk of the system. (5 refs).

  17. Sensitivity of the Speech Intelligibility Index to the Assumed Dynamic Range

    Science.gov (United States)

    Jin, In-Ki; Kates, James M.; Arehart, Kathryn H.

    2017-01-01

    Purpose: This study aims to evaluate the sensitivity of the speech intelligibility index (SII) to the assumed speech dynamic range (DR) in different languages and with different types of stimuli. Method: Intelligibility prediction uses the absolute transfer function (ATF) to map the SII value to the predicted intelligibility for a given stimuli.…

  18. The Contribution of Matched Envelope Dynamic Range to the Binaural Benefits in Simulated Bilateral Electric Hearing

    Science.gov (United States)

    Chen, Fei; Wong, Lena L. N.; Qiu, Jianxin; Liu, Yehai; Azimi, Behnam; Hu, Yi

    2013-01-01

    Purpose: This study examined the effects of envelope dynamic-range mismatch on the intelligibility of Mandarin speech in noise by simulated bilateral electric hearing. Method: Noise-vocoded Mandarin speech, corrupted by speech-shaped noise at 5 and 0 dB signal-to-noise ratios, was presented unilaterally or bilaterally to 10 normal-hearing…

  19. A Hybrid Shared-Memory Parallel Max-Tree Algorithm for Extreme Dynamic-Range Images

    NARCIS (Netherlands)

    Moschini, Ugo; Meijster, Arnold; Wilkinson, Michael

    Max-trees, or component trees, are graph structures that represent the connected components of an image in a hierarchical way. Nowadays, many application fields rely on images with high-dynamic range or floating point values. Efficient sequential algorithms exist to build trees and compute

  20. Enhancing the dynamic range of Ultrasound Imaging Velocimetry using interleaved imaging

    NARCIS (Netherlands)

    Poelma, C.; Fraser, K.H.

    2013-01-01

    In recent years, non-invasive velocity field measurement based on correlation of ultrasound images has been introduced as a promising technique for fundamental research into disease processes, as well as a diagnostic tool. A major drawback of the method is the relatively limited dynamic range when

  1. A highly sensitive RF-to-DC power converter with an extended dynamic range

    KAUST Repository

    Almansouri, Abdullah Saud Mohammed; Ouda, Mahmoud H.; Salama, Khaled N.

    2017-01-01

    This paper proposes a highly sensitive RF-to-DC power converter with an extended dynamic range that is designed to operate at the medical band 433 MHz and simulated using 0.18 μm CMOS technology. Compared to the conventional fully cross

  2. High Dynamic Range adaptive ΔΣ-based Focal Plane Array architecture

    KAUST Repository

    Yao, Shun; Kavusi, Sam; Salama, Khaled N.

    2012-01-01

    In this paper, an Adaptive Delta-Sigma based architecture for High Dynamic Range (HDR) Focal Plane Arrays is presented. The noise shaping effect of the Delta-Sigma modulation in the low end, and the distortion noise induced in the high end of Photo

  3. What controls the population dynamics of the invasive thistle Carduus nutans in its native range?

    NARCIS (Netherlands)

    Jongejans, E.; Sheppard, A.W.; Shea, K.

    2006-01-01

    1. The invasive thistle Carduus nutans causes major economic losses in the Americas, Australia and New Zealand. For the first time, we have modelled its population dynamics in its native range, Eurasia, where it rarely reaches problematic densities, in order to identify ways to improve management

  4. Fractional quantum mechanics on networks: Long-range dynamics and quantum transport.

    Science.gov (United States)

    Riascos, A P; Mateos, José L

    2015-11-01

    In this paper we study the quantum transport on networks with a temporal evolution governed by the fractional Schrödinger equation. We generalize the dynamics based on continuous-time quantum walks, with transitions to nearest neighbors on the network, to the fractional case that allows long-range displacements. By using the fractional Laplacian matrix of a network, we establish a formalism that combines a long-range dynamics with the quantum superposition of states; this general approach applies to any type of connected undirected networks, including regular, random, and complex networks, and can be implemented from the spectral properties of the Laplacian matrix. We study the fractional dynamics and its capacity to explore the network by means of the transition probability, the average probability of return, and global quantities that characterize the efficiency of this quantum process. As a particular case, we explore analytically these quantities for circulant networks such as rings, interacting cycles, and complete graphs.

  5. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems

    International Nuclear Information System (INIS)

    Yang, Ge; Wang, Jun; Fang, Wen

    2015-01-01

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems

  6. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems

    Science.gov (United States)

    Yang, Ge; Wang, Jun; Fang, Wen

    2015-04-01

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.

  7. Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ge; Wang, Jun [School of Science, Beijing Jiaotong University, Beijing 100044 (China); Fang, Wen, E-mail: fangwen@bjtu.edu.cn [School of Economics and Management, Beijing Jiaotong University, Beijing 100044 (China)

    2015-04-15

    In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.

  8. Short-Range Electron Transfer in Reduced Flavodoxin: Ultrafast Nonequilibrium Dynamics Coupled with Protein Fluctuations.

    Science.gov (United States)

    Kundu, Mainak; He, Ting-Fang; Lu, Yangyi; Wang, Lijuan; Zhong, Dongping

    2018-05-03

    Short-range electron transfer (ET) in proteins is an ultrafast process on the similar timescales as local protein-solvent fluctuations thus the two dynamics are coupled. Here, we use semiquinone flavodoxin and systematically characterized the photoinduced redox cycle with eleven mutations of different aromatic electron donors (tryptophan and tyrosine) and local residues to change redox properties. We observed the forward and backward ET dynamics in a few picoseconds, strongly following a stretched behavior resulting from a coupling between local environment relaxations and these ET processes. We further observed the hot vibrational-state formation through charge recombination and the subsequent cooling dynamics also in a few picoseconds. Combined with the ET studies in oxidized flavodoxin, these results coherently reveal the evolution of the ET dynamics from single to stretched exponential behaviors and thus elucidate critical timescales for the coupling. The observed hot vibration-state formation is robust and should be considered in all photoinduced back ET processes in flavoproteins.

  9. UMER: An analog computer for dynamics of swarms interacting via long-range forces

    International Nuclear Information System (INIS)

    Kishek, R.A.; Bai, G.; Bernal, S.; Feldman, D.; Godlove, T.F.; Haber, I.; O'Shea, P.G.; Quinn, B.; Papadopoulos, C.; Reiser, M.; Stratakis, D.; Tian, K.; Tobin, C.J.; Walter, M.

    2006-01-01

    Some of the most challenging and interesting problems in nature involve large numbers of objects or particles mutually interacting through long-range forces. Examples range from galaxies and plasmas to flocks of birds and traffic flow on a highway. Even in cases where the form of the interacting force is precisely known, such as the 1/r 2 -dependent Coulomb and gravitational forces, such problems present a formidable theoretical and modeling challenge for large numbers of interacting bodies. This paper reports on a newly constructed, scaled particle accelerator that will serve as an experimental testbed for the dynamics of swarms interacting through long-range forces. Primarily designed for intense beam dynamics studies for advanced accelerators, the University of Maryland Electron Ring (UMER) design is described in detail and an update on commissioning is provided. An example application to a system other than a charged particle beam is discussed

  10. Thermal and dynamic range characterization of a photonics-based RF amplifier

    Science.gov (United States)

    Noque, D. F.; Borges, R. M.; Muniz, A. L. M.; Bogoni, A.; Cerqueira S., Arismar, Jr.

    2018-05-01

    This work reports a thermal and dynamic range characterization of an ultra-wideband photonics-based RF amplifier for microwave and mm-waves future 5G optical-wireless networks. The proposed technology applies the four-wave mixing nonlinear effect to provide RF amplification in analog and digital radio-over-fiber systems. The experimental analysis from 300 kHz to 50 GHz takes into account different figures of merit, such as RF gain, spurious-free dynamic range and RF output power stability as a function of temperature. The thermal characterization from -10 to +70 °C demonstrates a 27 dB flat photonics-assisted RF gain over the entire frequency range under real operational conditions of a base station for illustrating the feasibility of the photonics-assisted RF amplifier for 5G networks.

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

    Science.gov (United States)

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

    2015-10-01

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

  12. Unmanned Ground Vehicle Perception Using Thermal Infrared Cameras

    Science.gov (United States)

    Rankin, Arturo; Huertas, Andres; Matthies, Larry; Bajracharya, Max; Assad, Christopher; Brennan, Shane; Bellutta, Paolo; Sherwin, Gary W.

    2011-01-01

    The ability to perform off-road autonomous navigation at any time of day or night is a requirement for some unmanned ground vehicle (UGV) programs. Because there are times when it is desirable for military UGVs to operate without emitting strong, detectable electromagnetic signals, a passive only terrain perception mode of operation is also often a requirement. Thermal infrared (TIR) cameras can be used to provide day and night passive terrain perception. TIR cameras have a detector sensitive to either mid-wave infrared (MWIR) radiation (3-5?m) or long-wave infrared (LWIR) radiation (8-12?m). With the recent emergence of high-quality uncooled LWIR cameras, TIR cameras have become viable passive perception options for some UGV programs. The Jet Propulsion Laboratory (JPL) has used a stereo pair of TIR cameras under several UGV programs to perform stereo ranging, terrain mapping, tree-trunk detection, pedestrian detection, negative obstacle detection, and water detection based on object reflections. In addition, we have evaluated stereo range data at a variety of UGV speeds, evaluated dual-band TIR classification of soil, vegetation, and rock terrain types, analyzed 24 hour water and 12 hour mud TIR imagery, and analyzed TIR imagery for hazard detection through smoke. Since TIR cameras do not currently provide the resolution available from megapixel color cameras, a UGV's daytime safe speed is often reduced when using TIR instead of color cameras. In this paper, we summarize the UGV terrain perception work JPL has performed with TIR cameras over the last decade and describe a calibration target developed by General Dynamics Robotic Systems (GDRS) for TIR cameras and other sensors.

  13. Lithium-ion battery dynamic model for wide range of operating conditions

    DEFF Research Database (Denmark)

    Stroe, Ana-Irina; Stroe, Daniel-Ioan; Swierczynski, Maciej Jozef

    2017-01-01

    In order to analyze the dynamic behavior of a Lithium-ion (Li-ion) battery and to determine their suitability for various applications, battery models are needed. An equivalent electrical circuit model is the most common way of representing the behavior of a Li-ion battery. There are different...... characterization tests performed for a wide range of operating conditions (temperature, load current and state-of-charge) on a commercial available 13Ah high-power lithium titanate oxide battery cell. The obtained results were used to parametrize the proposed dynamic model of the battery cell. To assess...

  14. A high speed, wide dynamic range digitizer circuit for photomultiplier tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yarema, R.J.; Foster, G.W.; Knickerbocker, K.; Sarraj, M.; Tschirhart, R.; Whitmore, J.; Zimmerman, T. [Fermi National Accelerator Lab., Batavia, IL (United States); Lindgren, M. [Univ. of California, Los Angeles, CA (United States). Physics Dept.

    1994-06-01

    High energy physics experiments running at high interaction rates frequently require long record lengths for determining a level 1 trigger. The easiest way to provide a long event record is by digital means. In applications requiring wide dynamic range, however, digitization of an analog signal to obtain the digital record has been impossible due to lack of high speed, wide range FADCs. One such application is the readout of thousands of photomultiplier tubes in fixed target and colliding beam experiment calorimeters. A circuit has been designed for digitizing PMT signals over a wide dynamic range (17--18 bits) with 8 bits of resolution at rates up to 53 MHz. Output from the circuit is in a floating point format with a 4 bit exponent and an 8 bit mantissa. The heart of the circuit is a full custom integrated circuit called the QIE (Charge Integrator and Encoder). The design of the QIE and associated circuitry reported here permits operation over a 17 bit dynamic range. Tests of the circuit with a PMT input and a pulsed laser have provided respectable results with little off line correction. Performance of the circuit for demanding applications can be significantly enhanced with additional off line correction. Circuit design, packaging issues, and test results of a multirange device are presented for the first time.

  15. A high speed, wide dynamic range digitizer circuit for photomultiplier tubes

    International Nuclear Information System (INIS)

    Yarema, R.J.; Foster, G.W.; Knickerbocker, K.; Sarraj, M.; Tschirhart, R.; Whitmore, J.; Zimmerman, T.; Lindgren, M.

    1994-06-01

    High energy physics experiments running at high interaction rates frequently require long record lengths for determining a level 1 trigger. The easiest way to provide a long event record is by digital means. In applications requiring wide dynamic range, however, digitization of an analog signal to obtain the digital record has been impossible due to lack of high speed, wide range FADCs. One such application is the readout of thousands of photomultiplier tubes in fixed target and colliding beam experiment calorimeters. A circuit has been designed for digitizing PMT signals over a wide dynamic range (17--18 bits) with 8 bits of resolution at rates up to 53 MHz. Output from the circuit is in a floating point format with a 4 bit exponent and an 8 bit mantissa. The heart of the circuit is a full custom integrated circuit called the QIE (Charge Integrator and Encoder). The design of the QIE and associated circuitry reported here permits operation over a 17 bit dynamic range. Tests of the circuit with a PMT input and a pulsed laser have provided respectable results with little off line correction. Performance of the circuit for demanding applications can be significantly enhanced with additional off line correction. Circuit design, packaging issues, and test results of a multirange device are presented for the first time

  16. Prediction of left main or 3-vessel disease using myocardial perfusion reserve on dynamic thallium-201 single-photon emission computed tomography with a semiconductor gamma camera.

    Science.gov (United States)

    Shiraishi, Shinya; Sakamoto, Fumi; Tsuda, Noriko; Yoshida, Morikatsu; Tomiguchi, Seiji; Utsunomiya, Daisuke; Ogawa, Hisao; Yamashita, Yasuyuki

    2015-01-01

    Myocardial perfusion imaging (MPI) may fail to detect balanced ischemia. We evaluated myocardial perfusion reserve (MPR) using Tl dynamic single-photon emission computed tomography (SPECT) and a novel cadmium zinc telluride (CZT) camera for predicting 3-vessel or left main coronary artery disease (CAD). METHODS AND RESULTS: A total of 55 consecutive patients with suspected CAD underwent SPECT-MPI and coronary angiography. The MPR index was calculated using the standard 2-compartment kinetic model. We analyzed the utility of MPR index, other SPECT findings, and various clinical variables. On multivariate analysis, MPR index and history of previous myocardial infarction (MI) predicted left main and 3-vessel disease. The area under the receiver operating characteristic curve was 0.81 for MPR index, 0.699 for history of previous MI, and 0.86 for MPR index plus history of previous MI. MPR index ≤1.5 yielded the highest diagnostic accuracy. Sensitivity, specificity, and accuracy were 86%, 78%, and 80%, respectively, for MPR index, 64%, 76%, 73% for previous MI, and 57%, 93%, and 84% for MPR index plus history of previous MI. Quantification of MPR using dynamic SPECT and a novel CZT camera may identify balanced ischemia in patients with left main or 3-vessel disease.

  17. Gamma camera

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  18. Monte Carlo Simulations of High-speed, Time-gated MCP-based X-ray Detectors: Saturation Effects in DC and Pulsed Modes and Detector Dynamic Range

    International Nuclear Information System (INIS)

    Kruschwitz, Craig; Ming Wu; Moy, Ken; Rochau, Greg

    2008-01-01

    We present here results of continued efforts to understand the performance of microchannel plate (MCP)-based, high-speed, gated, x-ray detectors. This work involves the continued improvement of a Monte Carlo simulation code to describe MCP performance coupled with experimental efforts to better characterize such detectors. Our goal is a quantitative description of MCP saturation behavior in both static and pulsed modes. We have developed a new model of charge buildup on the walls of the MCP channels and measured its effect on MCP gain. The results are compared to experimental data obtained with a short-pulse, high-intensity ultraviolet laser; these results clearly demonstrate MCP saturation behavior in both DC and pulsed modes. The simulations compare favorably to the experimental results. The dynamic range of the detectors in pulsed operation is of particular interest when fielding an MCP-based camera. By adjusting the laser flux we study the linear range of the camera. These results, too, are compared to our simulations

  19. Volcano dome dynamics at Mount St. Helens: Deformation and intermittent subsidence monitored by seismicity and camera imagery pixel offsets

    Science.gov (United States)

    Salzer, Jacqueline T.; Thelen, Weston A.; James, Mike R.; Walter, Thomas R.; Moran, Seth C.; Denlinger, Roger P.

    2016-01-01

    The surface deformation field measured at volcanic domes provides insights into the effects of magmatic processes, gravity- and gas-driven processes, and the development and distribution of internal dome structures. Here we study short-term dome deformation associated with earthquakes at Mount St. Helens, recorded by a permanent optical camera and seismic monitoring network. We use Digital Image Correlation (DIC) to compute the displacement field between successive images and compare the results to the occurrence and characteristics of seismic events during a 6 week period of dome growth in 2006. The results reveal that dome growth at Mount St. Helens was repeatedly interrupted by short-term meter-scale downward displacements at the dome surface, which were associated in time with low-frequency, large-magnitude seismic events followed by a tremor-like signal. The tremor was only recorded by the seismic stations closest to the dome. We find a correlation between the magnitudes of the camera-derived displacements and the spectral amplitudes of the associated tremor. We use the DIC results from two cameras and a high-resolution topographic model to derive full 3-D displacement maps, which reveals internal dome structures and the effect of the seismic activity on daily surface velocities. We postulate that the tremor is recording the gravity-driven response of the upper dome due to mechanical collapse or depressurization and fault-controlled slumping. Our results highlight the different scales and structural expressions during growth and disintegration of lava domes and the relationships between seismic and deformation signals.

  20. Development and application of an automatic system for measuring the laser camera

    International Nuclear Information System (INIS)

    Feng Shuli; Peng Mingchen; Li Kuncheng

    2004-01-01

    Objective: To provide an automatic system for measuring imaging quality of laser camera, and to make an automatic measurement and analysis system. Methods: On the special imaging workstation (SGI 540), the procedure was written by using Matlab language. An automatic measurement and analysis system of imaging quality for laser camera was developed and made according to the imaging quality measurement standard of laser camera of International Engineer Commission (IEC). The measurement system used the theories of digital signal processing, and was based on the characteristics of digital images, as well as put the automatic measurement and analysis of laser camera into practice by the affiliated sample pictures of the laser camera. Results: All the parameters of imaging quality of laser camera, including H-D and MTF curve, low and middle and high resolution of optical density, all kinds of geometry distort, maximum and minimum density, as well as the dynamic range of gray scale, could be measured by this system. The system was applied for measuring the laser cameras in 20 hospitals in Beijing. The measuring results showed that the system could provide objective and quantitative data, and could accurately evaluate the imaging quality of laser camera, as well as correct the results made by manual measurement based on the affiliated sample pictures of the laser camera. Conclusion: The automatic measuring system of laser camera is an effective and objective tool for testing the quality of the laser camera, and the system makes a foundation for the future research

  1. Wavepacket dynamics in one-dimensional system with long-range correlated disorder

    Science.gov (United States)

    Yamada, Hiroaki S.

    2018-03-01

    We numerically investigate dynamical property in the one-dimensional tight-binding model with long-range correlated disorder having power spectrum 1 /fα (α: spectrum exponent) generated by Fourier filtering method. For relatively small α MSD) of the initially localized wavepacket shows ballistic spread and localizes as time elapses. It is shown that α-dependence of the dynamical localization length determined by the MSD exhibits a simple scaling law in the localization regime for the relatively weak disorder strength W. Furthermore, scaled MSD by the dynamical localization length almost obeys an universal function from the ballistic to the localization regime in the various combinations of the parameters α and W.

  2. Territorial dynamics and stable home range formation for central place foragers.

    Directory of Open Access Journals (Sweden)

    Jonathan R Potts

    Full Text Available Uncovering the mechanisms behind territory formation is a fundamental problem in behavioural ecology. The broad nature of the underlying conspecific avoidance processes are well documented across a wide range of taxa. Scent marking in particular is common to a large range of terrestrial mammals and is known to be fundamental for communication. However, despite its importance, exact quantification of the time-scales over which scent cues and messages persist remains elusive. Recent work by the present authors has begun to shed light on this problem by modelling animals as random walkers with scent-mediated interaction processes. Territories emerge as dynamic objects that continually change shape and slowly move without settling to a fixed location. As a consequence, the utilisation distribution of such an animal results in a slowly increasing home range, as shown for urban foxes (Vulpes vulpes. For certain other species, however, home ranges reach a stable state. The present work shows that stable home ranges arise when, in addition to scent-mediated conspecific avoidance, each animal moves as a central place forager. That is, the animal's movement has a random aspect but is also biased towards a fixed location, such as a den or nest site. Dynamic territories emerge but the probability distribution of the territory border locations reaches a steady state, causing stable home ranges to emerge from the territorial dynamics. Approximate analytic expressions for the animal's probability density function are derived. A programme is given for using these expressions to quantify both the strength of the animal's movement bias towards the central place and the time-scale over which scent messages persist. Comparisons are made with previous theoretical work modelling central place foragers with conspecific avoidance. Some insights into the mechanisms behind allometric scaling laws of animal space use are also given.

  3. Novel computer-based endoscopic camera

    Science.gov (United States)

    Rabinovitz, R.; Hai, N.; Abraham, Martin D.; Adler, Doron; Nissani, M.; Fridental, Ron; Vitsnudel, Ilia

    1995-05-01

    We have introduced a computer-based endoscopic camera which includes (a) unique real-time digital image processing to optimize image visualization by reducing over exposed glared areas and brightening dark areas, and by accentuating sharpness and fine structures, and (b) patient data documentation and management. The image processing is based on i Sight's iSP1000TM digital video processor chip and Adaptive SensitivityTM patented scheme for capturing and displaying images with wide dynamic range of light, taking into account local neighborhood image conditions and global image statistics. It provides the medical user with the ability to view images under difficult lighting conditions, without losing details `in the dark' or in completely saturated areas. The patient data documentation and management allows storage of images (approximately 1 MB per image for a full 24 bit color image) to any storage device installed into the camera, or to an external host media via network. The patient data which is included with every image described essential information on the patient and procedure. The operator can assign custom data descriptors, and can search for the stored image/data by typing any image descriptor. The camera optics has extended zoom range of f equals 20 - 45 mm allowing control of the diameter of the field which is displayed on the monitor such that the complete field of view of the endoscope can be displayed on all the area of the screen. All these features provide versatile endoscopic camera with excellent image quality and documentation capabilities.

  4. Multifractal analysis of the long-range correlations in the cardiac dynamics of Drosophila melanogaster

    International Nuclear Information System (INIS)

    Vitanov, Nikolay K.; Yankulova, Elka D.

    2006-01-01

    By means of the multifractal detrended fluctuation analysis (MFDFA) we investigate long-range correlations in the interbeat time series of heart activity of Drosophila melanogaster-the classical object of research in genetics. Our main investigation tool are the fractal spectra f(α) and h(q) by means of which we trace the correlation properties of Drosophila heartbeat dynamics for three consequent generations of species. We observe that opposite to the case of humans the time series of the heartbeat activity of healthy Drosophila do not have scaling properties. Time series from species with genetic defects can be long-range correlated. Different kinds of genetic heart defects lead to different shape of the fractal spectra. The fractal heartbeat dynamics of Drosophila is transferred from generation to generation

  5. A highly sensitive RF-to-DC power converter with an extended dynamic range

    KAUST Repository

    Almansouri, Abdullah Saud Mohammed

    2017-10-24

    This paper proposes a highly sensitive RF-to-DC power converter with an extended dynamic range that is designed to operate at the medical band 433 MHz and simulated using 0.18 μm CMOS technology. Compared to the conventional fully cross-coupled rectifier, the proposed design offers 3.2× the dynamic range. It is also highly sensitive and requires −18 dBm of input power to produce a 1 V-output voltage when operating with a 100 kΩ load. Furthermore, the proposed design offers an open circuit sensitivity of −23.4 dBm and a peak power conversion efficiency of 67%.

  6. A high sensitive 66 dB linear dynamic range receiver for 3-D laser radar

    Science.gov (United States)

    Ma, Rui; Zheng, Hao; Zhu, Zhangming

    2017-08-01

    This study presents a CMOS receiver chip realized in 0.18 μm standard CMOS technology and intended for high precision 3-D laser radar. The chip includes an adjustable gain transimpedance pre-amplifier, a post-amplifier and two timing comparators. An additional feedback is employed in the regulated cascode transimpedance amplifier to decrease the input impedance, and a variable gain transimpedance amplifier controlled by digital switches and analog multiplexer is utilized to realize four gain modes, extending the input dynamic range. The measurement shows that the highest transimpedance of the channel is 50 k {{Ω }}, the uncompensated walk error is 1.44 ns in a wide linear dynamic range of 66 dB (1:2000), and the input referred noise current is 2.3 pA/\\sqrt{{Hz}} (rms), resulting in a very low detectable input current of 1 μA with SNR = 5.

  7. Robust image registration for multiple exposure high dynamic range image synthesis

    Science.gov (United States)

    Yao, Susu

    2011-03-01

    Image registration is an important preprocessing technique in high dynamic range (HDR) image synthesis. This paper proposed a robust image registration method for aligning a group of low dynamic range images (LDR) that are captured with different exposure times. Illumination change and photometric distortion between two images would result in inaccurate registration. We propose to transform intensity image data into phase congruency to eliminate the effect of the changes in image brightness and use phase cross correlation in the Fourier transform domain to perform image registration. Considering the presence of non-overlapped regions due to photometric distortion, evolutionary programming is applied to search for the accurate translation parameters so that the accuracy of registration is able to be achieved at a hundredth of a pixel level. The proposed algorithm works well for under and over-exposed image registration. It has been applied to align LDR images for synthesizing high quality HDR images..

  8. STUDY OF USING CANON 1000D DIGITAL CAMERA FOR MULTIZONE PHOTOGRAPHY WITH SPATIALLY-RESOLVED SPECTRAL DEVICES

    Directory of Open Access Journals (Sweden)

    K. N. Kaplevskiy

    2013-01-01

    Full Text Available The possibility of use a CANON 1000D digital camera for multizone photography is demonstrated. It is found that a dynamic range of the recorded light intensities is varied from 260 to 3650 quantization levels of the ADC. Linearity of the light-sensitive element of the camera has been studied in dependence on its illumination and exposure time.

  9. Dynamic range of frontoparietal functional modulation is associated with working memory capacity limitations in older adults.

    Science.gov (United States)

    Hakun, Jonathan G; Johnson, Nathan F

    2017-11-01

    Older adults tend to over-activate regions throughout frontoparietal cortices and exhibit a reduced range of functional modulation during WM task performance compared to younger adults. While recent evidence suggests that reduced functional modulation is associated with poorer task performance, it remains unclear whether reduced range of modulation is indicative of general WM capacity-limitations. In the current study, we examined whether the range of functional modulation observed over multiple levels of WM task difficulty (N-Back) predicts in-scanner task performance and out-of-scanner psychometric estimates of WM capacity. Within our sample (60-77years of age), age was negatively associated with frontoparietal modulation range. Individuals with greater modulation range exhibited more accurate N-Back performance. In addition, despite a lack of significant relationships between N-Back and complex span task performance, range of frontoparietal modulation during the N-Back significantly predicted domain-general estimates of WM capacity. Consistent with previous cross-sectional findings, older individuals with less modulation range exhibited greater activation at the lowest level of task difficulty but less activation at the highest levels of task difficulty. Our results are largely consistent with existing theories of neurocognitive aging (e.g. CRUNCH) but focus attention on dynamic range of functional modulation asa novel marker of WM capacity-limitations in older adults. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Molecular dynamics simulations of ion range profiles for heavy ions in light targets

    Energy Technology Data Exchange (ETDEWEB)

    Lan, C. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 (China); Xue, J.M. [State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 (China); Zhang, Y., E-mail: Zhangy1@ornl.gov [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Morris, J.R. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhu, Z. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Gao, Y.; Wang, Y.G.; Yan, S. [State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871 (China); Weber, W.J. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2012-09-01

    The determination of stopping powers for slow heavy ions in targets containing light elements is important to accurately describe ion-solid interactions, evaluate ion irradiation effects and predict ion ranges for device fabrication and nuclear applications. Recently, discrepancies of up to 40% between the experimental results and SRIM (Stopping and Range of Ions in Matter) predictions of ion ranges for heavy ions with medium and low energies (<{approx}25 keV/nucleon) in light elemental targets have been reported. The longer experimental ion ranges indicate that the stopping powers used in the SRIM code are overestimated. Here, a molecular dynamics simulation scheme is developed to calculate the ion ranges of heavy ions in light elemental targets. Electronic stopping powers generated from both a reciprocity approach and the SRIM code are used to investigate the influence of electronic stopping on ion range profiles. The ion range profiles for Au and Pb ions in SiC and Er ions in Si, with energies between 20 and 5250 keV, are simulated. The simulation results show that the depth profiles of implanted ions are deeper and in better agreement with the experiments when using the electronic stopping power values derived from the reciprocity approach. These results indicate that the origin of the discrepancy in ion ranges between experimental results and SRIM predictions in the low energy region may be an overestimation of the electronic stopping powers used in SRIM.

  11. Face recognition based on matching of local features on 3D dynamic range sequences

    Science.gov (United States)

    Echeagaray-Patrón, B. A.; Kober, Vitaly

    2016-09-01

    3D face recognition has attracted attention in the last decade due to improvement of technology of 3D image acquisition and its wide range of applications such as access control, surveillance, human-computer interaction and biometric identification systems. Most research on 3D face recognition has focused on analysis of 3D still data. In this work, a new method for face recognition using dynamic 3D range sequences is proposed. Experimental results are presented and discussed using 3D sequences in the presence of pose variation. The performance of the proposed method is compared with that of conventional face recognition algorithms based on descriptors.

  12. Surface and finite size effect on fluctuations dynamics in nanoparticles with long-range order

    Science.gov (United States)

    Morozovska, A. N.; Eliseev, E. A.

    2010-02-01

    The influence of surface and finite size on the dynamics of the order parameter fluctuations and critical phenomena in the three-dimensional (3D)-confined systems with long-range order was not considered theoretically. In this paper, we study the influence of surface and finite size on the dynamics of the order parameter fluctuations in the particles of arbitrary shape. We consider concrete examples of the spherical and cylindrical ferroic nanoparticles within Landau-Ginzburg-Devonshire phenomenological approach. Allowing for the strong surface energy contribution in micro and nanoparticles, the analytical expressions derived for the Ornstein-Zernike correlator of the long-range order parameter spatial-temporal fluctuations, dynamic generalized susceptibility, relaxation times, and correlation radii discrete spectra are different from those known for bulk systems. Obtained analytical expressions for the correlation function of the order parameter spatial-temporal fluctuations in micro and nanosized systems can be useful for the quantitative analysis of the dynamical structural factors determined from magnetic resonance diffraction and scattering spectra. Besides the practical importance of the correlation function for the analysis of the experimental data, derived expressions for the fluctuations strength determine the fundamental limits of phenomenological theories applicability for 3D-confined systems.

  13. Dynamic Gesture Recognition with a Terahertz Radar Based on Range Profile Sequences and Doppler Signatures.

    Science.gov (United States)

    Zhou, Zhi; Cao, Zongjie; Pi, Yiming

    2017-12-21

    The frequency of terahertz radar ranges from 0.1 THz to 10 THz, which is higher than that of microwaves. Multi-modal signals, including high-resolution range profile (HRRP) and Doppler signatures, can be acquired by the terahertz radar system. These two kinds of information are commonly used in automatic target recognition; however, dynamic gesture recognition is rarely discussed in the terahertz regime. In this paper, a dynamic gesture recognition system using a terahertz radar is proposed, based on multi-modal signals. The HRRP sequences and Doppler signatures were first achieved from the radar echoes. Considering the electromagnetic scattering characteristics, a feature extraction model is designed using location parameter estimation of scattering centers. Dynamic Time Warping (DTW) extended to multi-modal signals is used to accomplish the classifications. Ten types of gesture signals, collected from a terahertz radar, are applied to validate the analysis and the recognition system. The results of the experiment indicate that the recognition rate reaches more than 91%. This research verifies the potential applications of dynamic gesture recognition using a terahertz radar.

  14. A High Dynamic-Range Beam Position Measurement System for ELSA-2

    CERN Document Server

    Balleyguier, P; Guimbal, P; Borrion, H

    2003-01-01

    New beamlines are presently under construction for ELSA, a 20 MeV electron linac located at Bruyères-le-Châtel. These lines need a beam position measurement system filling the following requirements: small footprint, wide dynamic range, single-bunch/multi-bunch capability, simple design. We designed a compact 4-stripline sensor and an electronic treatment chain based on logarithmic amplifiers. This paper presents the design, cold and hot test results.

  15. Rabbit System. Low cost, high reliability front end electronics featuring 16 bit dynamic range

    International Nuclear Information System (INIS)

    Drake, G.; Droege, T.F.; Nelson, C.A. Jr.; Turner, K.J.; Ohska, T.K.

    1985-10-01

    A new crate-based front end system has been built which features low cost, compact packaging, command capability, 16 bit dynamic range digitization, and a high degree of redundancy. The crate can contain a variety of instrumentation modules, and is designed to be situated close to the detector. The system is suitable for readout of a large number of channels via parallel multiprocessor data acquisition

  16. Dynamic Range Enhancement of High-Speed Electrical Signal Data via Non-Linear Compression

    Science.gov (United States)

    Laun, Matthew C. (Inventor)

    2016-01-01

    Systems and methods for high-speed compression of dynamic electrical signal waveforms to extend the measuring capabilities of conventional measuring devices such as oscilloscopes and high-speed data acquisition systems are discussed. Transfer function components and algorithmic transfer functions can be used to accurately measure signals that are within the frequency bandwidth but beyond the voltage range and voltage resolution capabilities of the measuring device.

  17. Low Parametric Sensitivity Realizations with relaxed L2-dynamic-range-scaling constraints

    OpenAIRE

    Hilaire , Thibault

    2009-01-01

    This paper presents a new dynamic-range scaling for the implementation of filters/controllers in state-space form. Relaxing the classical L2-scaling constraints by specific fixed-point considerations allows for a higher degree of freedom for the optimal L2-parametric sensitivity problem. However, overflows in the implementation are still prevented. The underlying constrained problem is converted into an unconstrained problem for which a solution can be provided. This leads to realizations whi...

  18. Extending the dynamic range of silicon photomultipliers without increasing pixel count

    International Nuclear Information System (INIS)

    Johnson, Kurtis F.

    2010-01-01

    A silicon photomultiplier, sometimes called 'multipixel photon counter', which we here refer to as a 'SiPM', is a photo-sensitive device built from an avalanche photodiode array of pixels on a common silicon substrate, such that it can detect single photon events. The dimensions of a pixel may vary from 20 to 100 μm and their density can be greater than 1000 per square millimeter. Each pixel in a SiPM operates in Geiger mode and is coupled to the output by a quenching resistor. Although each pixel operates in digital mode, the SiPM is an analog device because all the pixels are read in parallel, making it possible to generate signals within a dynamic range from a single photon to a large number of photons, ultimately limited by the number of pixels on the chip. In this note we describe a simple and general method of increasing the dynamic range of a SiPM beyond that one may naively assume from the shape of the cumulative distribution function of the SiPM response to the average number of photons per pixel. We show that by rendering the incoming flux of photons to be non-uniform in a prescribed manner, a significant increase in dynamic range is achievable. Such re-distribution of the incoming flux may be accomplished with simple, non-focusing lenses, prisms, interference films, mirrors or attenuating films. Almost any optically non-inert interceding device can increase the dynamic range of the SiPM.

  19. New facade concepts ranging from statics to dynamics; Neue Fassadenkonzepte. Von der Statik zur Dynamik

    Energy Technology Data Exchange (ETDEWEB)

    Kranz, H.R. [Siemens AG, Karlsruhe (Germany)

    1995-12-31

    In chapter 9 of the anthology about building control new facade concepts are presented, including new facade technologies, conductivity of new facade concepts and combination of new technologies. The whole complex ranging from statics to dynamics is explained. (BWI) [Deutsch] Kapitel 9 des Sammelbandes ueber Building Control stellt neue Fassadenkonzepte vor: Neue Fassadentechnologien, Leitfunktionen neuer Fassadenkonzepte, Kombination neuer Technologien. In diesem Zusammenhang wird der gesamte Komplex von der Statik bis zur Dynamik behandelt. (BWI)

  20. Seasonal source-sink dynamics at the edge of a species' range.

    Science.gov (United States)

    Kanda, L Leann; Fuller, Todd K; Sievert, Paul R; Kellogg, Robert L

    2009-06-01

    The roles of dispersal and population dynamics in determining species' range boundaries recently have received theoretical attention but little empirical work. Here we provide data on survival, reproduction, and movement for a Virginia opossum (Didelphis virginiana) population at a local distributional edge in central Massachusetts (USA). Most juvenile females that apparently exploited anthropogenic resources survived their first winter, whereas those using adjacent natural resources died of starvation. In spring, adult females recolonized natural areas. A life-table model suggests that a population exploiting anthropogenic resources may grow, acting as source to a geographically interlaced sink of opossums using only natural resources, and also providing emigrants for further range expansion to new human-dominated landscapes. In a geographical model, this source-sink dynamic is consistent with the local distribution identified through road-kill surveys. The Virginia opossum's exploitation of human resources likely ameliorates energetically restrictive winters and may explain both their local distribution and their northward expansion in unsuitable natural climatic regimes. Landscape heterogeneity, such as created by urbanization, may result in source-sink dynamics at highly localized scales. Differential fitness and individual dispersal movements within local populations are key to generating regional distributions, and thus species ranges, that exceed expectations.

  1. The high dynamic range pixel array detector (HDR-PAD): Concept and design

    Energy Technology Data Exchange (ETDEWEB)

    Shanks, Katherine S.; Philipp, Hugh T.; Weiss, Joel T.; Becker, Julian; Tate, Mark W. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Gruner, Sol M., E-mail: smg26@cornell.edu [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853 (United States); Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853 (United States)

    2016-07-27

    Experiments at storage ring light sources as well as at next-generation light sources increasingly require detectors capable of high dynamic range operation, combining low-noise detection of single photons with large pixel well depth. XFEL sources in particular provide pulse intensities sufficiently high that a purely photon-counting approach is impractical. The High Dynamic Range Pixel Array Detector (HDR-PAD) project aims to provide a dynamic range extending from single-photon sensitivity to 10{sup 6} photons/pixel in a single XFEL pulse while maintaining the ability to tolerate a sustained flux of 10{sup 11} ph/s/pixel at a storage ring source. Achieving these goals involves the development of fast pixel front-end electronics as well as, in the XFEL case, leveraging the delayed charge collection due to plasma effects in the sensor. A first prototype of essential electronic components of the HDR-PAD readout ASIC, exploring different options for the pixel front-end, has been fabricated. Here, the HDR-PAD concept and preliminary design will be described.

  2. Seasonal source-sink dynamics at the edge of a species' range

    Science.gov (United States)

    Kanda, L.L.; Fuller, T.K.; Sievert, P.R.; Kellogg, R.L.

    2009-01-01

    The roles of dispersal and population dynamics in determining species' range boundaries recently have received theoretical attention but little empirical work. Here we provide data on survival, reproduction, and movement for a Virginia opossum (Didelphis virginiana) population at a local distributional edge in central Massachusetts (USA). Most juvenile females that apparently exploited anthropogenic resources survived their first winter, whereas those using adjacent natural resources died of starvation. In spring, adult females recolonized natural areas. A life-table model suggests that a population exploiting anthropogenic resources may grow, acting as source to a geographically interlaced sink of opossums using only natural resources, and also providing emigrants for further range expansion to new human-dominated landscapes. In a geographical model, this source-sink dynamic is consistent with the local distribution identified through road-kill surveys. The Virginia opossum's exploitation of human resources likely ameliorates energetically restrictive winters and may explain both their local distribution and their northward expansion in unsuitable natural climatic regimes. Landscape heterogeneity, such as created by urbanization, may result in source-sink dynamics at highly localized scales. Differential fitness and individual dispersal movements within local populations are key to generating regional distributions, and thus species ranges, that exceed expectations. ?? 2009 by the Ecological Society of America.

  3. Transmitted wavefront testing with large dynamic range based on computer-aided deflectometry

    Science.gov (United States)

    Wang, Daodang; Xu, Ping; Gong, Zhidong; Xie, Zhongmin; Liang, Rongguang; Xu, Xinke; Kong, Ming; Zhao, Jun

    2018-06-01

    The transmitted wavefront testing technique is demanded for the performance evaluation of transmission optics and transparent glass, in which the achievable dynamic range is a key issue. A computer-aided deflectometric testing method with fringe projection is proposed for the accurate testing of transmitted wavefronts with a large dynamic range. Ray tracing of the modeled testing system is carried out to achieve the virtual ‘null’ testing of transmitted wavefront aberrations. The ray aberration is obtained from the ray tracing result and measured slope, with which the test wavefront aberration can be reconstructed. To eliminate testing system modeling errors, a system geometry calibration based on computer-aided reverse optimization is applied to realize accurate testing. Both numerical simulation and experiments have been carried out to demonstrate the feasibility and high accuracy of the proposed testing method. The proposed testing method can achieve a large dynamic range compared with the interferometric method, providing a simple, low-cost and accurate way for the testing of transmitted wavefronts from various kinds of optics and a large amount of industrial transmission elements.

  4. Towards Adaptive Virtual Camera Control In Computer Games

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2011-01-01

    Automatic camera control aims to define a framework to control virtual camera movements in dynamic and unpredictable virtual environments while ensuring a set of desired visual properties. We inves- tigate the relationship between camera placement and playing behaviour in games and build a user...... model of the camera behaviour that can be used to control camera movements based on player preferences. For this purpose, we collect eye gaze, camera and game-play data from subjects playing a 3D platform game, we cluster gaze and camera information to identify camera behaviour profiles and we employ...... camera control in games is discussed....

  5. Development of an all-optical framing camera and its application on the Z-pinch.

    Science.gov (United States)

    Song, Yan; Peng, Bodong; Wang, Hong-Xing; Song, Guzhou; Li, Binkang; Yue, Zhiqin; Li, Yang; Sun, Tieping; Xu, Qing; Ma, Jiming; Sheng, Liang; Han, Changcai; Duan, Baojun; Yao, Zhiming; Yan, Weipeng

    2017-12-11

    An all-optical framing camera has been developed which measures the spatial profile of photons flux by utilizing a laser beam to probe the refractive index change in an indium phosphide semiconductor. This framing camera acquires two frames with the time resolution of about 1.5 ns and the inter frame separation time of about 13 ns by angularly multiplexing the probe beam on to the semiconductor. The spatial resolution of this camera has been estimated to be about 140 μm and the spectral response of this camera has also been theoretically investigated in 5 eV-100 KeV range. This camera has been applied in investigating the imploding dynamics of the molybdenum planar wire array Z-pinch on the 1-MA "QiangGuang-1" facility. This framing camera can provide an alternative scheme for high energy density physics experiments.

  6. Gamma camera

    International Nuclear Information System (INIS)

    Berninger, W.H.

    1975-01-01

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

  7. Radioisotope camera

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  8. The dynamical mechanical properties of tungsten under compression at working temperature range of divertors

    International Nuclear Information System (INIS)

    Zhu, C.C.; Song, Y.T.; Peng, X.B.; Wei, Y.P.; Mao, X.; Li, W.X.; Qian, X.Y.

    2016-01-01

    In the divertor structure of ITER and EAST with mono-block module, tungsten plays not only a role of armor material but also a role of structural material, because electromagnetic (EM) impact will be exerted on tungsten components in VDEs or CQ. The EM loads can reach to 100 MN, which would cause high strain rates. In addition, directly exposed to high-temperature plasma, the temperature regime of divertor components is complex. Aiming at studying dynamical response of tungsten divertors under EM loads, an experiment on tungsten employed in EAST divertors was performed using a Kolsky bar system. The testing strain rates and temperatures is derived from actual working conditions, which makes the constitutive equation concluded by using John-Cook model and testing data very accurate and practical. The work would give a guidance to estimate the dynamical response, fatigue life and damage evolution of tungsten divertor components under EM impact loads. - Graphical abstract: From the comparison between the experimental curves and the predicted curves calculated by adopting the corrected m, it is very clear that the new model is of great capability to explain the deformation behavior of the tungsten material under dynamic compression at high temperatures. (EC, PC and PCM refers to experimental curve, predicted curve and predicted curve with a corrected m. Different colors represent different scenarios.). - Highlights: • Test research on dynamic properties of tungsten at working temperature range and strain rate range of divertors. • Constitutive equation descrbing strain hardening, strain rate hardening and temperature softening. • A guidance to estimate dynamical response and damage evolution of tungsten divertor components under impact.

  9. Technique for increasing dynamic range of space-borne ion composition instruments

    International Nuclear Information System (INIS)

    Burch, J.L.; Miller, G.P.; Santos, A. de los; Pollock, C.J.; Pope, S.E.; Valek, P. W.; Young, D.T.

    2005-01-01

    The dynamic range of ion composition spectrometers is limited by several factors, including saturation of particle counters and spillover of signals from highly dominant species into channels tuned to minor species. Instruments designed for composition measurements of hot plasmas in space can suffer greatly from both of these problems because of the wide energy range required and the wide disparity in fluxes encountered in various regions of interest. In order to detect minor ions in regions of very weak fluxes, geometry factors need to be as large as possible within the mass and volume resources available. As a result, problems with saturation by the dominant fluxes and spillover to minor-ion channels in plasma regions with intense fluxes become especially acute. This article reports on a technique for solving the dynamic-range problem in the few eV to several keV energy/charge range that is of central importance for space physics research where the dominant ion is of low mass/charge (typically H + ), and the minor ions are of higher mass/charge (typically O + ). The technique involves employing a radio-frequency modulation of the deflection electric field in the back section of an electrostatic analyzer in a time-of-flight instrument. This technique is shown to reduce H + counts by a controllable amount of up to factors of 1000 while reducing O + counts by only a few percent that can be calibrated

  10. Comparison of linear intrascan and interscan dynamic ranges of Orbitrap and ion-mobility time-of-flight mass spectrometers.

    Science.gov (United States)

    Kaufmann, Anton; Walker, Stephan

    2017-11-30

    The linear intrascan and interscan dynamic ranges of mass spectrometers are important in metabolome and residue analysis. A large linear dynamic range is mandatory if both low- and high-abundance ions have to be detected and quantitated in heavy matrix samples. These performance criteria, as provided by modern high-resolution mass spectrometry (HRMS), were systematically investigated. The comparison included two generations of Orbitraps, and an ion mobility quadrupole time-of-flight (QTOF) system In addition, different scan modes, as provided by the utilized instruments, were investigated. Calibration curves of different compounds covering a concentration range of five orders of magnitude were measured to evaluate the linear interscan dynamic range. The linear intrascan dynamic range and the resulting mass accuracy were evaluated by repeating these measurements in the presence of a very intense background. Modern HRMS instruments can show linear dynamic ranges of five orders of magnitude. Often, however, the linear dynamic range is limited by the detection capability (sensitivity and selectivity) and by the electrospray ionization. Orbitraps, as opposed to TOF instruments, show a reduced intrascan dynamic range. This is due to the limited C-trap and Orbitrap capacity. The tested TOF instrument shows poorer mass accuracies than the Orbitraps. In contrast, hyphenation with an ion-mobility device seems not to affect the linear dynamic range. The linear dynamic range of modern HRMS instrumentation has been significantly improved. This also refers to the virtual absence of systematic mass shifts at high ion abundances. The intrascan dynamic range of the current Orbitrap technology may still be a limitation when analyzing complex matrix extracts. On the other hand, the linear dynamic range is not only limited by the detector technology, but can also be shortened by peripheral devices, where the ionization and transfer of ions take place. Copyright © 2017 John Wiley

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

    Science.gov (United States)

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

    2017-10-01

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

  12. Implementing Molecular Dynamics for Hybrid High Performance Computers - 1. Short Range Forces

    International Nuclear Information System (INIS)

    Brown, W. Michael; Wang, Peng; Plimpton, Steven J.; Tharrington, Arnold N.

    2011-01-01

    The use of accelerators such as general-purpose graphics processing units (GPGPUs) have become popular in scientific computing applications due to their low cost, impressive floating-point capabilities, high memory bandwidth, and low electrical power requirements. Hybrid high performance computers, machines with more than one type of floating-point processor, are now becoming more prevalent due to these advantages. In this work, we discuss several important issues in porting a large molecular dynamics code for use on parallel hybrid machines - (1) choosing a hybrid parallel decomposition that works on central processing units (CPUs) with distributed memory and accelerator cores with shared memory, (2) minimizing the amount of code that must be ported for efficient acceleration, (3) utilizing the available processing power from both many-core CPUs and accelerators, and (4) choosing a programming model for acceleration. We present our solution to each of these issues for short-range force calculation in the molecular dynamics package LAMMPS. We describe algorithms for efficient short range force calculation on hybrid high performance machines. We describe a new approach for dynamic load balancing of work between CPU and accelerator cores. We describe the Geryon library that allows a single code to compile with both CUDA and OpenCL for use on a variety of accelerators. Finally, we present results on a parallel test cluster containing 32 Fermi GPGPUs and 180 CPU cores.

  13. Smartphone-based accelerometry is a valid tool for measuring dynamic changes in knee extension range of motion

    DEFF Research Database (Denmark)

    Støve, Morten Pallisgaard; Palsson, Thorvaldur Skuli; Hirata, Rogerio Pessoto

    2018-01-01

    Introduction: Measurement of static joint range of motion is used extensively in orthopaedic and rehabilitative communities to benchmark treatment efficacy. Static measures are, however, insufficient in providing detailed information about patient impairments. Dynamic range of motion measures cou...

  14. A large dynamic range radiation-tolerant analog memory in a quarter- micron CMOS technology

    CERN Document Server

    Anelli, G; Rivetti, A

    2001-01-01

    An analog memory prototype containing 8*128 cells has been designed in a commercial quarter-micron CMOS process. The aim of this work is to investigate the possibility of designing large dynamic range mixed-mode switched capacitor circuits for high-energy physics (HEP) applications in deep submicron CMOS technologies. Special layout techniques have been used to make the circuit radiation tolerant. The memory cells employ gate-oxide capacitors for storage, permitting a very high density. A voltage write-voltage read architecture has been chosen to minimize the sensitivity to absolute capacitor values. The measured input voltage range is 2.3 V (the power supply voltage V/sub DD/ is equal to 2.5 V), with a linearity of almost 8 bits over 2 V. The dynamic range is more than 11 bits. The pedestal variation is +or-0.5 mV peak-to-peak. The noise measured, which is dominated by the noise of the measurement setup, is around 0.8 mV rms. The characteristics of the memory have been measured before irradiation and after 1...

  15. A large dynamic range radiation tolerant analog memory in a quarter micron CMOS technology

    CERN Document Server

    Anelli, G; Rivetti, A

    2000-01-01

    A 8*128 cell analog memory prototype has been designed in a commercial 0.25 jam CMOS process. The aim of this work was to investigate the possibility of designing large dynamic range mixed- mode switched capacitor circuits for High-Energy Physics (HEP) applications in deep submicron CMOS technologies. Special layout techniques have been used to make the circuit radiation tolerant left bracket 1 right bracket . The memory cells employ gate-oxide capacitors for storage, allowing for a very high density. A voltage write - voltage read architecture has been chosen to minimize the sensitivity to absolute capacitor values. The measured input voltage range is 2.3 V (V//D//D = 2.5 V), with a linearity of at least 7.5 bits over 2 V. The dynamic range is more than 11 bits. The pedestal variation is plus or minus 0.5 mV peak-to-peak. The noise measured, which is dominated by the noise of the measurement setup, is around 0.8 mV rms. The characteristics of the memory have been measured before irradiation and after lOMrd (...

  16. A high linearity current mode multiplier/divider with a wide dynamic range

    International Nuclear Information System (INIS)

    Liao Pengfei; Luo Ping; Zhang Bo; Li Zhaoji

    2012-01-01

    A high linearity current mode multiplier/divider (CMM/D) with a wide dynamic range is presented. The proposed CMM/D is based on the voltage—current characteristic of the diode, thus wide dynamic range is achieved. In addition, high linearity is achieved because high accuracy current mirrors are adopted and the output current is insensitive to the temperature and device parameters of the fabrication process. Furthermore, no extra bias current for all input signals is required and thus power saving is realized. With proper selection of establishing the input terminal, the proposed circuit can perform as a multifunction circuit to be operated as a multiplier/divider, without changing its topology. The proposed circuit is implemented in a 0.25 μm BCD process and the chip area is 0.26 × 0.24 mm 2 . The simulation and measurement results show that the maximum static linearity error is ±1.8% and the total harmonic distortion is 0.4% while the input current ranges from 0 to 200 μA. (semiconductor integrated circuits)

  17. Configurable Electronics with Low Noise and 14-bit Dynamic Range for Photodiode-based Photon Detectors

    CERN Document Server

    Müller, H; Yin, Z; Zhou, D; Cao, X; Li, Q; Liu, Y; Zou, F; Skaali, B; Awes, T C

    2006-01-01

    We describe the principles and measured performance characteristics of custom configurable 32-channel shaper/digitizer Front End Electronics (FEE) cards with 14-bit dynamic range for use with gain-adjustable photon detectors. The electronics has been designed for the PHOS calorimeter of ALICE with avalanche photodiode (APD) readout operated at -25 C ambient temperature and a signal shaping time of $1 {\\mu}s$. The electronics has also been adopted by the EMCal detector of ALICE with the same APD readout, but operated at an ambient temperature of +20 C and with a shaping time of 100ns. The CR-RC2 signal shapers on the FEE cards are implemented in discrete logic on a 10-layer board with two shaper sections for each input channel. The two shaper sections with gain ratio of 16:1 are digitized by 10-bit ADCs and provide an effective dynamic range of 14 bits. Gain adjustment for each individual APD is available through 32 bias voltage control registers of 10-bit range. The fixed gains and shaping times of the pole-z...

  18. An operating principle of the turtle utricle to detect wide dynamic range.

    Science.gov (United States)

    Nam, Jong-Hoon

    2018-03-01

    The utricle encodes both static information such as head orientation, and dynamic information such as vibrations. It is not well understood how the utricle can encode both static and dynamic information for a wide dynamic range (from 2 times the gravitational acceleration; from DC to > 1000 Hz vibrations). Using computational models of the hair cells in the turtle utricle, this study presents an explanation on how the turtle utricle encodes stimulations over such a wide dynamic range. Two hair bundles were modeled using the finite element method-one representing the striolar hair cell (Cell S), and the other representing the medial extrastriolar hair cell (Cell E). A mechano-transduction (MET) channel model was incorporated to compute MET current (i MET ) due to hair bundle deflection. A macro-mechanical model of the utricle was used to compute otoconial motions from head accelerations (a Head ). According to known anatomical data, Cell E has a long kinocilium that is embedded into the stiff otoconial layer. Unlike Cell E, the hair bundle of Cell S falls short of the otoconial layer. Considering such difference in the mechanical connectivity between the hair cell bundle and the otoconial layer, three cases were simulated: Cell E displacement-clamped, Cell S viscously-coupled, and Cell S displacement-clamped. Head accelerations at different amplitude levels and different frequencies were simulated for the three cases. When a realistic head motion was simulated, Cell E was responsive to head orientation, while the viscously-coupled Cell S was responsive to fast head motion imitating the feeding strike of a turtle. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. In-medium short-range dynamics of nucleons: Recent theoretical and experimental advances

    Energy Technology Data Exchange (ETDEWEB)

    Atti, Claudio Ciofi degli, E-mail: ciofi@pg.infn.it

    2015-08-14

    The investigation of in-medium short-range dynamics of nucleons, usually referred to as the study of short-range correlations (SRCs), is a key issue in nuclear and hadronic physics. As a matter of fact, even in the simplified assumption that the nucleus could be described as a system of protons and neutrons interacting via effective nucleon–nucleon (NN) interactions, several non trivial problems arise concerning the description of in-medium (NN short-range dynamics, namely: (i) the behavior of the NN interaction at short inter-nucleon distances in medium cannot be uniquely constrained by the experimental NN scattering phase shifts due to off-shell effects; (ii) by rigorous renormalization group (RG) techniques entire families of phase equivalent interactions differing in the short-range part can be derived; (iii) the in-medium NN interaction may be, in principle, different from the free one; (iv) when the short inter-nucleon separation is of the order of the nucleon size, the question arises of possible effects from quark and gluon degrees of freedom. For more than fifty years, experimental evidence of SRCs has been searched by means of various kinds of nuclear reactions, without however convincing results, mainly because the effects of SRCs arise from non observable quantities, like, e.g., the momentum distributions, and have been extracted from observable cross sections where short- and long-range effects, effects from nucleonic and non nucleonic degrees of freedom, and effects from final state interaction, could not be unambiguously separated out. Recent years, however, were witness of new progress in the field: from one side, theoretical and computational progress has allowed one to solve ab initio the many-nucleon non relativistic Schrödinger equation in terms of realistic NN interactions, obtaining realistic microscopic wave functions, unless the case of parametrized wave functions used frequently in the past, moreover the development of advanced

  20. High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

    Energy Technology Data Exchange (ETDEWEB)

    Giewekemeyer, Klaus, E-mail: klaus.giewekemeyer@xfel.eu [European XFEL GmbH, Hamburg (Germany); Philipp, Hugh T. [Cornell University, Ithaca, NY (United States); Wilke, Robin N. [Georg-August-Universität Göttingen, Göttingen (Germany); Aquila, Andrew [European XFEL GmbH, Hamburg (Germany); Osterhoff, Markus [Georg-August-Universität Göttingen, Göttingen (Germany); Tate, Mark W.; Shanks, Katherine S. [Cornell University, Ithaca, NY (United States); Zozulya, Alexey V. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Salditt, Tim [Georg-August-Universität Göttingen, Göttingen (Germany); Gruner, Sol M. [Cornell University, Ithaca, NY (United States); Cornell University, Ithaca, NY (United States); Kavli Institute of Cornell for Nanoscience, Ithaca, NY (United States); Mancuso, Adrian P. [European XFEL GmbH, Hamburg (Germany)

    2014-08-07

    The advantages of a novel wide dynamic range hard X-ray detector are demonstrated for (ptychographic) coherent X-ray diffractive imaging. Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 10{sup 8} 8-keV photons pixel{sup −1} s{sup −1}, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 10{sup 10} photons µm{sup −2} s{sup −1} within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described.

  1. Deeply trapped electrons in imaging plates and their utilization for extending the dynamic range

    International Nuclear Information System (INIS)

    Ohuchi, Hiroko; Kondo, Yasuhiro

    2010-01-01

    The absorption spectra of deep centers in an imaging plate (IP) made of BaFBr 0:85 I 0:15 :Eu 2+ have been studied in the ultraviolet region. Electrons trapped in deep centers are considered to be the cause of unerasable and reappearing latent images in IPs over-irradiated with X-rays. Deep centers showed a dominant peak at around 320 nm, followed by two small peaks at around 345 and 380 nm. By utilizing deeply trapped electrons, we have attempted to extend the dynamic range of an IP. The IP was irradiated by 150-kV X-rays with doses from 8.07 mGy to 80.7 Gy. Reading out the latent image by the stimulation of Eu 2+ luminescence with a 633-nm He-Ne laser light from a conventional Fuji reader showed a linear relationship with irradiated dose up to 0.8 Gy, but then becoming non-linear. After fully erasing with visible light, unerasable latent images were read out using 635-nm semi-conductor laser light combined with a photon-counting detection system. The dose-response curve so obtained gave a further two orders of magnitude extending the dynamic range up to 80.7 Gy. Comprehensive results indicate that electrons supplied from deep centers to the F centers provided the extended dynamic range after the F centers became saturated. Based on these facts, a model of the excitation of deeply trapped electrons and PSL processes is proposed.

  2. OTDM Networking for Short Range High-Capacity Highly Dynamic Networks

    DEFF Research Database (Denmark)

    Medhin, Ashenafi Kiros

    This PhD thesis aims at investigating the possibility of designing energy-efficient high-capacity (up to Tbit/s) optical network scenarios, leveraging on the effect of collective switching of many bits simultaneously, as is inherent in high bit rate serial optical data signals. The focus...... is on short range highly dynamic networks, catering to data center needs. The investigation concerns optical network scenarios, and experimental implementations of high bit rate serial data packet generation and reception, scalable optical packet labeling, simple optical label extraction and stable ultra...

  3. The Dynamic Range of Ultra-High Resolution Cryogenic Gamma-ray Spectrometers

    International Nuclear Information System (INIS)

    Ali, S; Terracol, S F; Drury, O B; Friedrich, S

    2005-01-01

    We are developing high-resolution cryogenic gamma-ray spectrometers for nuclear science and non-proliferation applications. The gamma-ray detectors are composed of a bulk superconducting Sn foil absorber attached to multilayer Mo/Cu transition-edge sensors (TES). The energy resolution achieved with a 1 x 1 x 0.25 mm 3 Sn absorber is 50 -90eV for γ-rays up to 100 keV and it decreases for large absorber sizes. We discuss the trade-offs between energy resolution and dynamic range, as well as development of TES arrays for higher count rates and better sensitivity

  4. The dynamic range of ultra-high-resolution cryogenic gamma-ray spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Shafinaz [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States); Terracol, Stephane F. [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States); Drury, Owen B. [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States); Friedrich, Stephan [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States)]. E-mail: friedrich1@llnl.gov

    2006-04-15

    We are developing high-resolution cryogenic gamma-ray spectrometers for nuclear science and non-proliferation applications. The gamma-ray detectors are composed of a bulk superconducting Sn foil absorber attached to a multilayer Mo/Cu transition-edge sensor (TES). The energy resolution of a detector with a 1x1x0.25 mm{sup 3} Sn absorber is 50-90 eV FWHM for {gamma}-rays up to 100 keV, and it decreases for larger absorbers. Here, we present the detector performance for different absorber volumes, and discuss the trade-offs between energy resolution and dynamic range.

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

    Science.gov (United States)

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

    1995-05-01

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

  6. Molecular dynamics simulations of short-range force systems on 1024-node hypercubes

    International Nuclear Information System (INIS)

    Plimpton, S.J.

    1990-01-01

    In this paper, two parallel algorithms for classical molecular dynamics are presented. The first assigns each processor to a subset of particles; the second assigns each to a fixed region of 3d space. The algorithms are implemented on 1024-node hypercubes for problems characterized by short-range forces, diffusion (so that each particle's neighbors change in time), and problem size ranging from 250 to 10000 particles. Timings for the algorithms on the 1024-node NCUBE/ten and the newer NCUBE 2 hypercubes are given. The latter is found to be competitive with a CRAY-XMP, running an optimized serial algorithm. For smaller problems the NCUBE 2 and CRAY-XMP are roughly the same; for larger ones the NCUBE 2 is up to twice as fast. Parallel efficiencies of the algorithms and communication parameters for the two hypercubes are also examined

  7. Adapting virtual camera behaviour through player modelling

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    Research in virtual camera control has focused primarily on finding methods to allow designers to place cameras effectively and efficiently in dynamic and unpredictable environments, and to generate complex and dynamic plans for cinematography in virtual environments. In this article, we propose...

  8. A wide-range model of two-group gross sections in the dynamics code HEXTRAN

    International Nuclear Information System (INIS)

    Kaloinen, E.; Peltonen, J.

    2002-01-01

    In dynamic analyses the thermal hydraulic conditions within the reactor core may have a large variation, which sets a special requirement on the modeling of cross sections. The standard model in the dynamics code HEXTRAN is the same as in the static design code HEXBU-3D/MODS. It is based on a linear and second order fitting of two-group cross sections on fuel and moderator temperature, moderator density and boron density. A new, wide-range model of cross sections developed in Fortum Nuclear Services for HEXBU-3D/MOD6 has been included as an option into HEXTRAN. In this model the nodal cross sections are constructed from seven state variables in a polynomial of more than 40 terms. Coefficients of the polynomial are created by a least squares fitting to the results of a large number of fuel assembly calculations. Depending on the choice of state variables for the spectrum calculations, the new cross section model is capable to cover local conditions from cold zero power to boiling at full power. The 5. dynamic benchmark problem of AER is analyzed with the new option and results are compared to calculations with the standard model of cross sections in HEXTRAN (Authors)

  9. Adaptive digital fringe projection technique for high dynamic range three-dimensional shape measurement.

    Science.gov (United States)

    Lin, Hui; Gao, Jian; Mei, Qing; He, Yunbo; Liu, Junxiu; Wang, Xingjin

    2016-04-04

    It is a challenge for any optical method to measure objects with a large range of reflectivity variation across the surface. Image saturation results in incorrect intensities in captured fringe pattern images, leading to phase and measurement errors. This paper presents a new adaptive digital fringe projection technique which avoids image saturation and has a high signal to noise ratio (SNR) in the three-dimensional (3-D) shape measurement of objects that has a large range of reflectivity variation across the surface. Compared to previous high dynamic range 3-D scan methods using many exposures and fringe pattern projections, which consumes a lot of time, the proposed technique uses only two preliminary steps of fringe pattern projection and image capture to generate the adapted fringe patterns, by adaptively adjusting the pixel-wise intensity of the projected fringe patterns based on the saturated pixels in the captured images of the surface being measured. For the bright regions due to high surface reflectivity and high illumination by the ambient light and surfaces interreflections, the projected intensity is reduced just to be low enough to avoid image saturation. Simultaneously, the maximum intensity of 255 is used for those dark regions with low surface reflectivity to maintain high SNR. Our experiments demonstrate that the proposed technique can achieve higher 3-D measurement accuracy across a surface with a large range of reflectivity variation.

  10. Optimal design of a vehicle magnetorheological damper considering the damping force and dynamic range

    International Nuclear Information System (INIS)

    Nguyen, Quoc-Hung; Choi, Seung-Bok

    2009-01-01

    This paper presents an optimal design of a passenger vehicle magnetorheological (MR) damper based on finite element analysis. The MR damper is constrained in a specific volume and the optimization problem identifies the geometric dimensions of the damper that minimize an objective function. The objective function consists of the damping force, the dynamic range, and the inductive time constant of the damper. After describing the configuration of the MR damper, the damping force and dynamic range are obtained on the basis of the Bingham model of an MR fluid. Then, the control energy (power consumption of the damper coil) and the inductive time constant are derived. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initial damper. Subsequently, the optimization procedure, using a golden-section algorithm and a local quadratic fitting technique, is constructed via commercial finite element method parametric design language. Using the developed optimization tool, optimal solutions of the MR damper, which are constrained in a specific cylindrical volume defined by its radius and height, are determined and a comparative work on damping force and inductive time constant between the initial and optimal design is undertaken

  11. Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Hongkui, E-mail: lvhk@ihep.ac.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Sheng, Xiangdong; He, Huihai; Liu, Jia [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Zhongquan [Shandong University, Jinan 250100 (China); Hou, Chao; Zhao, Jing [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-05-01

    In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km{sup 2} array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as “two outputs” device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×10{sup 5} photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 10{sup 5}, which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described.

  12. Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

    Science.gov (United States)

    Lv, Hongkui; Sheng, Xiangdong; He, Huihai; Liu, Jia; Zhang, Zhongquan; Hou, Chao; Zhao, Jing

    2015-05-01

    In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km2 array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as "two outputs" device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×105 photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 105, which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described.

  13. Extension of photomultiplier tube dynamic range for the LHAASO-KM2A electromagnetic particle detectors

    International Nuclear Information System (INIS)

    Lv, Hongkui; Sheng, Xiangdong; He, Huihai; Liu, Jia; Zhang, Zhongquan; Hou, Chao; Zhao, Jing

    2015-01-01

    In the Large High Altitude Air Shower Observatory (LHAASO), the 1 km 2 array (KM2A) requires linear measurement of optical intensity with a wide dynamic range. Over 5000 photomultiplier tubes (PMTs) are employed in this experiment and developed as “two outputs” device (anode and dynode) to meet the relevant requirements. In this study, the linearity of the anode and the eighth dynode (DY8), which is limited by space charge effects and mainly related to the relative dynode voltage ratios of the PMT divider, is examined. A voltage divider for the Hamamatsu R11102 PMT is designed and a dramatically enhanced linearity is demonstrated. Test results show that this design can cover a wide dynamic range from 20 to 2×10 5 photoelectrons and achieve a peak anode current of 380 mA at a PMT gain of 10 5 , which satisfies the requirements of KM2A electromagnetic particle detectors. The circuit design has been successfully simulated using the simulation software Multisim. The details of PMT performance tests and simulations are described

  14. Preamplifier development for high count-rate, large dynamic range readout of inorganic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Keshelashvili, Irakli; Erni, Werner; Steinacher, Michael; Krusche, Bernd; Collaboration: PANDA-Collaboration

    2013-07-01

    Electromagnetic calorimeter are central component of many experiments in nuclear and particle physics. Modern ''trigger less'' detectors run with very high count-rates, require good time and energy resolution, and large dynamic range. In addition photosensors and preamplifiers must work in hostile environments (magnetic fields). Due to later constraints mainly Avalanche Photo Diodes (APD's), Vacuum Photo Triodes (VPT's), and Vacuum Photo Tetrodes (VPTT's) are used. A disadvantage is their low gain which together with other requirements is a challenge for the preamplifier design. Our group has developed special Low Noise / Low Power (LNP) preamplifier for this purpose. They will be used to equip PANDA EMC forward end-cap (dynamic range 15'000, rate 1MHz), where the PWO II crystals and preamplifier have to run in an environment cooled down to -25{sup o}C. Further application is the upgrade of the Crystal Barrel detector at the Bonn ELSA accelerator with APD readout for which special temperature comparison of the APD gain and good time resolution is necessary. Development and all test procedures after the mass production done by our group during past several years in Basel University will be reported.

  15. A High-Dynamic-Range Optical Remote Sensing Imaging Method for Digital TDI CMOS

    Directory of Open Access Journals (Sweden)

    Taiji Lan

    2017-10-01

    Full Text Available The digital time delay integration (digital TDI technology of the complementary metal-oxide-semiconductor (CMOS image sensor has been widely adopted and developed in the optical remote sensing field. However, the details of targets that have low illumination or low contrast in scenarios of high contrast are often drowned out because of the superposition of multi-stage images in digital domain multiplies the read noise and the dark noise, thus limiting the imaging dynamic range. Through an in-depth analysis of the information transfer model of digital TDI, this paper attempts to explore effective ways to overcome this issue. Based on the evaluation and analysis of multi-stage images, the entropy-maximized adaptive histogram equalization (EMAHE algorithm is proposed to improve the ability of images to express the details of dark or low-contrast targets. Furthermore, in this paper, an image fusion method is utilized based on gradient pyramid decomposition and entropy weighting of different TDI stage images, which can improve the detection ability of the digital TDI CMOS for complex scenes with high contrast, and obtain images that are suitable for recognition by the human eye. The experimental results show that the proposed methods can effectively improve the high-dynamic-range imaging (HDRI capability of the digital TDI CMOS. The obtained images have greater entropy and average gradients.

  16. A research on radiation calibration of high dynamic range based on the dual channel CMOS

    Science.gov (United States)

    Ma, Kai; Shi, Zhan; Pan, Xiaodong; Wang, Yongsheng; Wang, Jianghua

    2017-10-01

    The dual channel complementary metal-oxide semiconductor (CMOS) can get high dynamic range (HDR) image through extending the gray level of the image by using image fusion with high gain channel image and low gain channel image in a same frame. In the process of image fusion with dual channel, it adopts the coefficients of radiation response of a pixel from dual channel in a same frame, and then calculates the gray level of the pixel in the HDR image. For the coefficients of radiation response play a crucial role in image fusion, it has to find an effective method to acquire these parameters. In this article, it makes a research on radiation calibration of high dynamic range based on the dual channel CMOS, and designs an experiment to calibrate the coefficients of radiation response for the sensor it used. In the end, it applies these response parameters in the dual channel CMOS which calibrates, and verifies the correctness and feasibility of the method mentioned in this paper.

  17. A high gain wide dynamic range transimpedance amplifier for optical receivers

    International Nuclear Information System (INIS)

    Liu Lianxi; Zou Jiao; Liu Shubin; Niu Yue; Zhu Zhangming; Yang Yintang; En Yunfei

    2014-01-01

    As the front-end preamplifiers in optical receivers, transimpedance amplifiers (TIAs) are commonly required to have a high gain and low input noise to amplify the weak and susceptible input signal. At the same time, the TIAs should possess a wide dynamic range (DR) to prevent the circuit from becoming saturated by high input currents. Based on the above, this paper presents a CMOS transimpedance amplifier with high gain and a wide DR for 2.5 Gbit/s communications. The TIA proposed consists of a three-stage cascade pull push inverter, an automatic gain control circuit, and a shunt transistor controlled by the resistive divider. The inductive-series peaking technique is used to further extend the bandwidth. The TIA proposed displays a maximum transimpedance gain of 88.3 dBΩ with the −3 dB bandwidth of 1.8 GHz, exhibits an input current dynamic range from 100 nA to 10 mA. The output voltage noise is less than 48.23 nV/√Hz within the −3 dB bandwidth. The circuit is fabricated using an SMIC 0.18 μm 1P6M RFCMOS process and dissipates a dc power of 9.4 mW with 1.8 V supply voltage. (semiconductor integrated circuits)

  18. High Dynamic Range RF Front End with Noise Cancellation and Linearization for WiMAX Receivers

    Directory of Open Access Journals (Sweden)

    J.-M. Wu

    2012-06-01

    Full Text Available This research deals with verification of the high dynamic range for a heterodyne radio frequency (RF front end. A 2.6 GHz RF front end is designed and implemented in a hybrid microwave integrated circuit (HMIC for worldwide interoperability for microwave access (WiMAX receivers. The heterodyne RF front end consists of a low-noise amplifier (LNA with noise cancellation, an RF bandpass filter (BPF, a downconverter with linearization, and an intermediate frequency (IF BPF. A noise canceling technique used in the low-noise amplifier eliminates a thermal noise and then reduces the noise figure (NF of the RF front end by 0.9 dB. Use of a downconverter with diode linearizer also compensates for gain compression, which increases the input-referred third-order intercept point (IIP3 of the RF front end by 4.3 dB. The proposed method substantially increases the spurious-free dynamic range (DRf of the RF front end by 3.5 dB.

  19. Large dynamic range pressure sensor based on two semicircle-holes microstructured fiber.

    Science.gov (United States)

    Liu, Zhengyong; Htein, Lin; Lee, Kang-Kuen; Lau, Kin-Tak; Tam, Hwa-Yaw

    2018-01-08

    This paper presents a sensitive and large dynamic range pressure sensor based on a novel birefringence microstructured optical fiber (MOF) deployed in a Sagnac interferometer configuration. The MOF has two large semicircle holes in the cladding and a rectangular strut with germanium-doped core in the center. The fiber structure permits surrounding pressure to induce large effective index difference between the two polarized modes. The calculated and measured group birefringence of the fiber are 1.49 × 10 -4 , 1.23 × 10 -4 , respectively, at the wavelength of 1550 nm. Experimental results shown that the pressure sensitivity of the sensor varied from 45,000 pm/MPa to 50,000 pm/MPa, and minimum detectable pressure of 80 Pa and dynamic range of better than 116 dB could be achieved with the novel fiber sensor. The proposed sensor could be used in harsh environment and is an ideal candidate for downhole applications where high pressure measurement at elevated temperature up to 250 °C is needed.

  20. Image processing pipeline for segmentation and material classification based on multispectral high dynamic range polarimetric images.

    Science.gov (United States)

    Martínez-Domingo, Miguel Ángel; Valero, Eva M; Hernández-Andrés, Javier; Tominaga, Shoji; Horiuchi, Takahiko; Hirai, Keita

    2017-11-27

    We propose a method for the capture of high dynamic range (HDR), multispectral (MS), polarimetric (Pol) images of indoor scenes using a liquid crystal tunable filter (LCTF). We have included the adaptive exposure estimation (AEE) method to fully automatize the capturing process. We also propose a pre-processing method which can be applied for the registration of HDR images after they are already built as the result of combining different low dynamic range (LDR) images. This method is applied to ensure a correct alignment of the different polarization HDR images for each spectral band. We have focused our efforts in two main applications: object segmentation and classification into metal and dielectric classes. We have simplified the segmentation using mean shift combined with cluster averaging and region merging techniques. We compare the performance of our segmentation with that of Ncut and Watershed methods. For the classification task, we propose to use information not only in the highlight regions but also in their surrounding area, extracted from the degree of linear polarization (DoLP) maps. We present experimental results which proof that the proposed image processing pipeline outperforms previous techniques developed specifically for MSHDRPol image cubes.

  1. High-dynamic range compressive spectral imaging by grayscale coded aperture adaptive filtering

    Directory of Open Access Journals (Sweden)

    Nelson Eduardo Diaz

    2015-09-01

    Full Text Available The coded aperture snapshot spectral imaging system (CASSI is an imaging architecture which senses the three dimensional informa-tion of a scene with two dimensional (2D focal plane array (FPA coded projection measurements. A reconstruction algorithm takes advantage of the compressive measurements sparsity to recover the underlying 3D data cube. Traditionally, CASSI uses block-un-block coded apertures (BCA to spatially modulate the light. In CASSI the quality of the reconstructed images depends on the design of these coded apertures and the FPA dynamic range. This work presents a new CASSI architecture based on grayscaled coded apertu-res (GCA which reduce the FPA saturation and increase the dynamic range of the reconstructed images. The set of GCA is calculated in a real-time adaptive manner exploiting the information from the FPA compressive measurements. Extensive simulations show the attained improvement in the quality of the reconstructed images when GCA are employed.  In addition, a comparison between traditional coded apertures and GCA is realized with respect to noise tolerance.

  2. Simultaneous broadband laser ranging and photonic Doppler velocimetry for dynamic compression experiments

    Energy Technology Data Exchange (ETDEWEB)

    La Lone, B. M., E-mail: lalonebm@nv.doe.gov; Marshall, B. R.; Miller, E. K.; Stevens, G. D.; Turley, W. D. [National Security Technologies, LLC, Special Technologies Laboratory, Santa Barbara, California 93111 (United States); Veeser, L. R. [National Security Technologies, LLC, Los Alamos Operations, Los Alamos, New Mexico 87544 (United States)

    2015-02-15

    A diagnostic was developed to simultaneously measure both the distance and velocity of rapidly moving surfaces in dynamic compression experiments, specifically non-planar experiments where integrating the velocity in one direction does not always give the material position accurately. The diagnostic is constructed mainly from fiber-optic telecommunications components. The distance measurement is based on a technique described by Xia and Zhang [Opt. Express 18, 4118 (2010)], which determines the target distance every 20 ns and is independent of the target speed. We have extended the full range of the diagnostic to several centimeters to allow its use in dynamic experiments, and we multiplexed it with a photonic Doppler velocimetry (PDV) system so that distance and velocity histories can be measured simultaneously using one fiber-optic probe. The diagnostic was demonstrated on a spinning square cylinder to show how integrating a PDV record can give an incorrect surface position and how the ranging diagnostic described here obtains it directly. The diagnostic was also tested on an explosive experiment where copper fragments and surface ejecta were identified in both the distance and velocity signals. We show how the distance measurements complement the velocity data. Potential applications are discussed.

  3. NV-CMOS HD camera for day/night imaging

    Science.gov (United States)

    Vogelsong, T.; Tower, J.; Sudol, Thomas; Senko, T.; Chodelka, D.

    2014-06-01

    SRI International (SRI) has developed a new multi-purpose day/night video camera with low-light imaging performance comparable to an image intensifier, while offering the size, weight, ruggedness, and cost advantages enabled by the use of SRI's NV-CMOS HD digital image sensor chip. The digital video output is ideal for image enhancement, sharing with others through networking, video capture for data analysis, or fusion with thermal cameras. The camera provides Camera Link output with HD/WUXGA resolution of 1920 x 1200 pixels operating at 60 Hz. Windowing to smaller sizes enables operation at higher frame rates. High sensitivity is achieved through use of backside illumination, providing high Quantum Efficiency (QE) across the visible and near infrared (NIR) bands (peak QE camera, which operates from a single 5V supply. The NVCMOS HD camera provides a substantial reduction in size, weight, and power (SWaP) , ideal for SWaP-constrained day/night imaging platforms such as UAVs, ground vehicles, fixed mount surveillance, and may be reconfigured for mobile soldier operations such as night vision goggles and weapon sights. In addition the camera with the NV-CMOS HD imager is suitable for high performance digital cinematography/broadcast systems, biofluorescence/microscopy imaging, day/night security and surveillance, and other high-end applications which require HD video imaging with high sensitivity and wide dynamic range. The camera comes with an array of lens mounts including C-mount and F-mount. The latest test data from the NV-CMOS HD camera will be presented.

  4. ATMOSPHERIC DYNAMICS OF TERRESTRIAL EXOPLANETS OVER A WIDE RANGE OF ORBITAL AND ATMOSPHERIC PARAMETERS

    Energy Technology Data Exchange (ETDEWEB)

    Kaspi, Yohai [Department of Earth and Planetary Sciences, Weizmann Institute of Science, 234 Herzl st., 76100, Rehovot (Israel); Showman, Adam P., E-mail: yohai.kaspi@weizmann.ac.il [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Blvd., Tucson, AZ 85721 (United States)

    2015-05-01

    The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate.

  5. Dynamic range in BOLD modulation: lifespan aging trajectories and association with performance.

    Science.gov (United States)

    Kennedy, Kristen M; Boylan, Maria A; Rieck, Jenny R; Foster, Chris M; Rodrigue, Karen M

    2017-12-01

    Alteration of dynamic range of modulation to cognitive difficulty has been proposed as a salient predictor of cognitive aging. Here, we examine in 171 adults (aged 20-94 years) the effects of age on dynamic modulation of blood oxygenation-level dependent activation to difficulty in parametrically increasing working memory (WM) load (0-, 2-, 3-, and 4-back conditions). First, we examined parametric increases and decreases in activation to increasing WM load (positive modulation effect and negative modulation effect). Second, we examined the effect of age on modulation to difficulty (WM load) to identify regions that differed with age as difficulty increased (age-related positive and negative modulation effects). Weakened modulation to difficulty with age was found in both the positive modulation (middle frontal, superior/inferior parietal) and negative modulation effect (deactivated) regions (insula, cingulate, medial superior frontal, fusiform, and parahippocampal gyri, hippocampus, and lateral occipital cortex). Age-related alterations to positive modulation emerged later in the lifespan than negative modulation. Furthermore, these effects were significantly coupled in that greater upmodulation was associated with lesser downmodulation. Importantly, greater fronto-parietal upmodulation to difficulty and greater downmodulation of deactivated regions were associated with better task accuracy and upmodulation with better WM span measured outside the scanner. These findings suggest that greater dynamic range of modulation of activation to cognitive challenge is in service of current task performance, as well as generalizing to cognitive ability beyond the scanner task, lending support to its utility as a marker of successful cognitive aging. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Estimating indices of range shifts in birds using dynamic models when detection is imperfect

    Science.gov (United States)

    Clement, Matthew J.; Hines, James E.; Nichols, James D.; Pardieck, Keith L.; Ziolkowski, David J.

    2016-01-01

    There is intense interest in basic and applied ecology about the effect of global change on current and future species distributions. Projections based on widely used static modeling methods implicitly assume that species are in equilibrium with the environment and that detection during surveys is perfect. We used multiseason correlated detection occupancy models, which avoid these assumptions, to relate climate data to distributional shifts of Louisiana Waterthrush in the North American Breeding Bird Survey (BBS) data. We summarized these shifts with indices of range size and position and compared them to the same indices obtained using more basic modeling approaches. Detection rates during point counts in BBS surveys were low, and models that ignored imperfect detection severely underestimated the proportion of area occupied and slightly overestimated mean latitude. Static models indicated Louisiana Waterthrush distribution was most closely associated with moderate temperatures, while dynamic occupancy models indicated that initial occupancy was associated with diurnal temperature ranges and colonization of sites was associated with moderate precipitation. Overall, the proportion of area occupied and mean latitude changed little during the 1997–2013 study period. Near-term forecasts of species distribution generated by dynamic models were more similar to subsequently observed distributions than forecasts from static models. Occupancy models incorporating a finite mixture model on detection – a new extension to correlated detection occupancy models – were better supported and may reduce bias associated with detection heterogeneity. We argue that replacing phenomenological static models with more mechanistic dynamic models can improve projections of future species distributions. In turn, better projections can improve biodiversity forecasts, management decisions, and understanding of global change biology.

  7. ATMOSPHERIC DYNAMICS OF TERRESTRIAL EXOPLANETS OVER A WIDE RANGE OF ORBITAL AND ATMOSPHERIC PARAMETERS

    International Nuclear Information System (INIS)

    Kaspi, Yohai; Showman, Adam P.

    2015-01-01

    The recent discoveries of terrestrial exoplanets and super-Earths extending over a broad range of orbital and physical parameters suggest that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super-Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone—including transitions to Snowball-like states and runaway-greenhouse feedbacks—depend on the equator-to-pole temperature differences, patterns of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, stellar flux, atmospheric mass, surface gravity, optical thickness, and planetary radius affect the atmospheric circulation and temperature distribution on such planets. Our simulations demonstrate that equator-to-pole temperature differences, meridional heat transport rates, structure and strength of the winds, and the hydrological cycle vary strongly with these parameters, implying that the sensitivity of the planet to global climate feedbacks will depend significantly on the atmospheric circulation. We elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley and Ferrel cells, and latitudinal temperature differences. Finally, we discuss the implications for understanding how the atmospheric circulation influences the global climate

  8. Photogrammetric measurement of 3D freeform millimetre-sized objects with micro features: an experimental validation of the close-range camera calibration model for narrow angles of view

    Science.gov (United States)

    Percoco, Gianluca; Sánchez Salmerón, Antonio J.

    2015-09-01

    The measurement of millimetre and micro-scale features is performed by high-cost systems based on technologies with narrow working ranges to accurately control the position of the sensors. Photogrammetry would lower the costs of 3D inspection of micro-features and would be applicable to the inspection of non-removable micro parts of large objects too. Unfortunately, the behaviour of photogrammetry is not known when photogrammetry is applied to micro-features. In this paper, the authors address these issues towards the application of digital close-range photogrammetry (DCRP) to the micro-scale, taking into account that in literature there are research papers stating that an angle of view (AOV) around 10° is the lower limit to the application of the traditional pinhole close-range calibration model (CRCM), which is the basis of DCRP. At first a general calibration procedure is introduced, with the aid of an open-source software library, to calibrate narrow AOV cameras with the CRCM. Subsequently the procedure is validated using a reflex camera with a 60 mm macro lens, equipped with extension tubes (20 and 32 mm) achieving magnification of up to 2 times approximately, to verify literature findings with experimental photogrammetric 3D measurements of millimetre-sized objects with micro-features. The limitation experienced by the laser printing technology, used to produce the bi-dimensional pattern on common paper, has been overcome using an accurate pattern manufactured with a photolithographic process. The results of the experimental activity prove that the CRCM is valid for AOVs down to 3.4° and that DCRP results are comparable with the results of existing and more expensive commercial techniques.

  9. Photogrammetric measurement of 3D freeform millimetre-sized objects with micro features: an experimental validation of the close-range camera calibration model for narrow angles of view

    International Nuclear Information System (INIS)

    Percoco, Gianluca; Sánchez Salmerón, Antonio J

    2015-01-01

    The measurement of millimetre and micro-scale features is performed by high-cost systems based on technologies with narrow working ranges to accurately control the position of the sensors. Photogrammetry would lower the costs of 3D inspection of micro-features and would be applicable to the inspection of non-removable micro parts of large objects too. Unfortunately, the behaviour of photogrammetry is not known when photogrammetry is applied to micro-features.In this paper, the authors address these issues towards the application of digital close-range photogrammetry (DCRP) to the micro-scale, taking into account that in literature there are research papers stating that an angle of view (AOV) around 10° is the lower limit to the application of the traditional pinhole close-range calibration model (CRCM), which is the basis of DCRP.At first a general calibration procedure is introduced, with the aid of an open-source software library, to calibrate narrow AOV cameras with the CRCM. Subsequently the procedure is validated using a reflex camera with a 60 mm macro lens, equipped with extension tubes (20 and 32 mm) achieving magnification of up to 2 times approximately, to verify literature findings with experimental photogrammetric 3D measurements of millimetre-sized objects with micro-features. The limitation experienced by the laser printing technology, used to produce the bi-dimensional pattern on common paper, has been overcome using an accurate pattern manufactured with a photolithographic process.The results of the experimental activity prove that the CRCM is valid for AOVs down to 3.4° and that DCRP results are comparable with the results of existing and more expensive commercial techniques. (paper)

  10. Investigating the Partial Relationships Between Testability and the Dynamic Range-to-Domain Ratio

    Directory of Open Access Journals (Sweden)

    Zuhoor Al-Khanjari

    2003-11-01

    Full Text Available The word ‘testability’ has been used variously in the software community to represent a number of different concepts such as how easy it is to test a program or how easy it is to achieve execution coverage of certain program components. Voas and colleagues have used the word to capture a slightly different notion, namely the ease with which faults, if present in a program, can be revealed by the testing process. The significance of this concept is twofold. First, if it is possible to measure or estimate testability, it can guide the tester in deciding where to focus the testing effort. Secondly, knowledge about what makes some programs more testable than others can guide the developer so that design-for-test features are built in to the software. The propagation, infection and execution (PIE analysis technique has been proposed as a way of estimating the Voas notion of testability. Unfortunately, estimating testability via the PIE technique is a difficult and costly process. However, Voas has suggested a link with the metric, domain-to-range ratio (DRR. This paper reviews the various testability concepts and summarises the PIE technique. A prototype tool developed by the authors to automate part of the PIE analysis is described and a method is proposed for dynamically determining the inverse of the domain-to-range ratio. This inverse ratio can be considered more natural in some sense and the idea of calculating its value from program execution leads to the possibility of automating its determination. Some experiments have been performed to investigate empirically whether there is a partial link between testability and this dynamic range-to-domain ratio (DRDR. Statistical tests have shown that for some programs and computational functions there is a strong relationship, but for others the relationship is weak.

  11. Metastability and avalanche dynamics in strongly correlated gases with long-range interactions

    Science.gov (United States)

    Hruby, Lorenz; Dogra, Nishant; Landini, Manuele; Donner, Tobias; Esslinger, Tilman

    2018-03-01

    We experimentally study the stability of a bosonic Mott insulator against the formation of a density wave induced by long-range interactions and characterize the intrinsic dynamics between these two states. The Mott insulator is created in a quantum degenerate gas of 87-Rubidium atoms, trapped in a 3D optical lattice. The gas is located inside and globally coupled to an optical cavity. This causes interactions of global range, mediated by photons dispersively scattered between a transverse lattice and the cavity. The scattering comes with an atomic density modulation, which is measured by the photon flux leaking from the cavity. We initialize the system in a Mott-insulating state and then rapidly increase the global coupling strength. We observe that the system falls into either of two distinct final states. One is characterized by a low photon flux, signaling a Mott insulator, and the other is characterized by a high photon flux, which we associate with a density wave. Ramping the global coupling slowly, we observe a hysteresis loop between the two states—a further signature of metastability. A comparison with a theoretical model confirms that the metastability originates in the competition between short- and global-range interactions. From the increasing photon flux monitored during the switching process, we find that several thousand atoms tunnel to a neighboring site on the timescale of the single-particle dynamics. We argue that a density modulation, initially forming in the compressible surface of the trapped gas, triggers an avalanche tunneling process in the Mott-insulating region.

  12. Gamma camera

    International Nuclear Information System (INIS)

    Conrad, B.; Heinzelmann, K.G.

    1975-01-01

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

  13. Scintillation camera

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  14. Dynamic studies of liver and thyroid function with the aid of a gamma camera and an on-line digital computer

    International Nuclear Information System (INIS)

    Raikar, U.R.; Ganatra, R.D.; Samuel, A.M.; Ramanathan, P.; Atmaram, S.H.

    1975-01-01

    Initial experience of dynamic studies with the use of a 16 K digital computer coupled to a scintillation camera is described. 1. A system for scoring bolus was developed taking into account peaking time, the ratio of counts at the peak and at 8 s after the peak and full width at half maximum. Various parameters affecting the boli are discussed. 2. A method is established for finding the slope of net early trapping of sup(99m)TcO 4 in the thyroid after subtraction of extrathyroidal vascular background. This value was found diagnostically useful in establishing the state of thyroid function in 26 patients. 3. Portal extraction half-times of various colloidal radiopharmaceuticals were studied in the first two-minute dynamic study of the liver. This determination provided a method of bioassay for the consistency of the production of colloid for liver scintigraphy. Differences were noted in the trapping time between the right and left lobes of the liver. 4. On the basis of portal extraction half-times, sup(99m)Tc phytate appeared to become colloidal instantaneously after injection into the circulation and its behavior in dynamic studies was more or less identical with that of the sup(99m)Tc-S-colloid. 5. Normal liver has a dual blood supply, while a malignancy in the liver derives blood from only the hepatic artery. Benign lesions such as abscesses and cysts are relatively avascular. This difference in the blood supply of benign and malignant space-occupying lesions in the liver was exploited in an early dynamic study of blood flow to offer a clue to the pathology of cold areas in 170 patients. (author)

  15. Camera network video summarization

    Science.gov (United States)

    Panda, Rameswar; Roy-Chowdhury, Amit K.

    2017-05-01

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

  16. New approach of financial volatility duration dynamics by stochastic finite-range interacting voter system.

    Science.gov (United States)

    Wang, Guochao; Wang, Jun

    2017-01-01

    We make an approach on investigating the fluctuation behaviors of financial volatility duration dynamics. A new concept of volatility two-component range intensity (VTRI) is developed, which constitutes the maximal variation range of volatility intensity and shortest passage time of duration, and can quantify the investment risk in financial markets. In an attempt to study and describe the nonlinear complex properties of VTRI, a random agent-based financial price model is developed by the finite-range interacting biased voter system. The autocorrelation behaviors and the power-law scaling behaviors of return time series and VTRI series are investigated. Then, the complexity of VTRI series of the real markets and the proposed model is analyzed by Fuzzy entropy (FuzzyEn) and Lempel-Ziv complexity. In this process, we apply the cross-Fuzzy entropy (C-FuzzyEn) to study the asynchrony of pairs of VTRI series. The empirical results reveal that the proposed model has the similar complex behaviors with the actual markets and indicate that the proposed stock VTRI series analysis and the financial model are meaningful and feasible to some extent.

  17. Diverse range dynamics and dispersal routes of plants on the Tibetan Plateau during the late Quaternary.

    Directory of Open Access Journals (Sweden)

    Haibin Yu

    Full Text Available Phylogeographical studies have suggested that several plant species on the Tibetan Plateau (TP underwent recolonization during the Quaternary and may have had distinct range dynamics in response to the last glacial. To further test this hypothesis and locate the possible historical dispersal routes, we selected 20 plant species from different parts of the TP and modeled their geographical distributions over four time periods using species distribution models (SDMs. Furthermore, we applied the least-cost path method together with SDMs and shared haplotypes to estimate their historical dispersal corridors. We identified three general scenarios of species distribution change during the late Quaternary: the 'contraction-expansion' scenario for species in the northeastern TP, the 'expansion-contraction' scenario for species in the southeast and the 'stable' scenario for widespread species. During the Quaternary, we identified that these species were likely to recolonize along the low-elevation valleys, huge mountain ranges and flat plateau platform (e.g. the Yarlung Zangbo Valley and the Himalaya. We inferred that Quaternary cyclic glaciations along with the various topographic and climatic conditions of the TP could have resulted in the diverse patterns of range shift and dispersal of Tibetan plant species. Finally, we believe that this study would provide valuable insights for the conservation of alpine species under future climate change.

  18. Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System

    Directory of Open Access Journals (Sweden)

    Yu Lu

    2016-04-01

    Full Text Available A new compact large field of view (FOV multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second.

  19. Development of a High Dynamic Range Pixel Array Detector for Synchrotrons and XFELs

    Science.gov (United States)

    Weiss, Joel Todd

    Advances in synchrotron radiation light source technology have opened new lines of inquiry in material science, biology, and everything in between. However, x-ray detector capabilities must advance in concert with light source technology to fully realize experimental possibilities. X-ray free electron lasers (XFELs) place particularly large demands on the capabilities of detectors, and developments towards diffraction-limited storage ring sources also necessitate detectors capable of measuring very high flux [1-3]. The detector described herein builds on the Mixed Mode Pixel Array Detector (MM-PAD) framework, developed previously by our group to perform high dynamic range imaging, and the Adaptive Gain Integrating Pixel Detector (AGIPD) developed for the European XFEL by a collaboration between Deustsches Elektronen-Synchrotron (DESY), the Paul-Scherrer-Institute (PSI), the University of Hamburg, and the University of Bonn, led by Heinz Graafsma [4, 5]. The feasibility of combining adaptive gain with charge removal techniques to increase dynamic range in XFEL experiments is assessed by simulating XFEL scatter with a pulsed infrared laser. The strategy is incorporated into pixel prototypes which are evaluated with direct current injection to simulate very high incident x-ray flux. A fully functional 16x16 pixel hybrid integrating x-ray detector featuring several different pixel architectures based on the prototypes was developed. This dissertation describes its operation and characterization. To extend dynamic range, charge is removed from the integration node of the front-end amplifier without interrupting integration. The number of times this process occurs is recorded by a digital counter in the pixel. The parameter limiting full well is thereby shifted from the size of an integration capacitor to the depth of a digital counter. The result is similar to that achieved by counting pixel array detectors, but the integrators presented here are designed to tolerate a

  20. CMOS Imaging Sensor Technology for Aerial Mapping Cameras

    Science.gov (United States)

    Neumann, Klaus; Welzenbach, Martin; Timm, Martin

    2016-06-01

    In June 2015 Leica Geosystems launched the first large format aerial mapping camera using CMOS sensor technology, the Leica DMC III. This paper describes the motivation to change from CCD sensor technology to CMOS for the development of this new aerial mapping camera. In 2002 the DMC first generation was developed by Z/I Imaging. It was the first large format digital frame sensor designed for mapping applications. In 2009 Z/I Imaging designed the DMC II which was the first digital aerial mapping camera using a single ultra large CCD sensor to avoid stitching of smaller CCDs. The DMC III is now the third generation of large format frame sensor developed by Z/I Imaging and Leica Geosystems for the DMC camera family. It is an evolution of the DMC II using the same system design with one large monolithic PAN sensor and four multi spectral camera heads for R,G, B and NIR. For the first time a 391 Megapixel large CMOS sensor had been used as PAN chromatic sensor, which is an industry record. Along with CMOS technology goes a range of technical benefits. The dynamic range of the CMOS sensor is approx. twice the range of a comparable CCD sensor and the signal to noise ratio is significantly better than with CCDs. Finally results from the first DMC III customer installations and test flights will be presented and compared with other CCD based aerial sensors.

  1. Miniature CCD X-Ray Imaging Camera Technology Final Report CRADA No. TC-773-94

    Energy Technology Data Exchange (ETDEWEB)

    Conder, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mummolo, F. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-19

    The goal of the project was to develop a compact, large active area, high spatial resolution, high dynamic range, charge-coupled device (CCD) camera to replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating X-rays. The camera head and controller needed to be capable of operation within a vacuum environment and small enough to be fielded within the small vacuum target chambers at LLNL.

  2. High Precision Stokes Polarimetry for Scattering Light using Wide Dynamic Range Intensity Detector

    Directory of Open Access Journals (Sweden)

    Shibata Shuhei

    2015-01-01

    Full Text Available This paper proposes a Stokes polarimetry for scattering light from a sample surface. To achieve a high accuracy measurement two approaches of an intensity detector and analysis algorism of a Stokes parameter were proposed. The dynamic range of this detector can achieve up to 1010 by combination of change of neutral-density (ND filters having different density and photon counting units. Stokes parameters can be measured by dual rotating of a retarder and an analyzer. The algorism of dual rotating polarimeter can be calibrated small linear diattenuation and linear retardance error of the retarder. This system can measured Stokes parameters from −20° to 70° of its scattering angle. It is possible to measure Stokes parameters of scattering of dust and scratch of optical device with high precision. This paper shows accuracy of this system, checking the polarization change of scattering angle and influence of beam size.

  3. Increase of the dynamic range of catchup experiments by high-pass filtering

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.J.

    1995-08-01

    The release-catchup shock experiment is an important tool for measuring the speed of sound in compressed matter. The catchup of the release wave to the leading shock is sensitively detected optically, through an indicating fluid which produces light approximately to the 4th power of the shock pressure. However, this sensitivity demands a dynamic range which exceeds the capabilities of our digitizer. The catchup signature lies at the top of a flat pulse, thus any signal clipping is a catastrophic loss of data. We have invented a simple and accurate method for recording the catchup signature that is insensitive to signal clipping. A high pass circuit prior to the digitizer is used with post experiment integration. The insensitivity to clipping allows recording the catchup signature at higher gain, and thus with an improved signal to noise ratio.

  4. New segmentation-based tone mapping algorithm for high dynamic range image

    Science.gov (United States)

    Duan, Weiwei; Guo, Huinan; Zhou, Zuofeng; Huang, Huimin; Cao, Jianzhong

    2017-07-01

    The traditional tone mapping algorithm for the display of high dynamic range (HDR) image has the drawback of losing the impression of brightness, contrast and color information. To overcome this phenomenon, we propose a new tone mapping algorithm based on dividing the image into different exposure regions in this paper. Firstly, the over-exposure region is determined using the Local Binary Pattern information of HDR image. Then, based on the peak and average gray of the histogram, the under-exposure and normal-exposure region of HDR image are selected separately. Finally, the different exposure regions are mapped by differentiated tone mapping methods to get the final result. The experiment results show that the proposed algorithm achieve the better performance both in visual quality and objective contrast criterion than other algorithms.

  5. Observation of plasma-facing-wall via high dynamic range imaging

    International Nuclear Information System (INIS)

    Villamayor, Michelle Marie S.; Rosario, Leo Mendel D.; Viloan, Rommel Paulo B.

    2013-01-01

    Pictures of plasmas and deposits in a discharge chamber taken by varying shutter speeds have been integrated into high dynamic range (HDR) images. The HDR images of a graphite target surface of a compact planar magnetron (CPM) discharge device have clearly indicated the erosion pattern of the target, which are correlated to the light intensity distribution of plasma during operation. Based upon the HDR image technique coupled to colorimetry, a formation history of dust-like deposits inside of the CPM chamber has been recorded. The obtained HDR images have shown how the patterns of deposits changed in accordance with discharge duration. Results show that deposition takes place near the evacuation ports during the early stage of the plasma discharge. Discoloration of the plasma-facing-walls indicating erosion and redeposition eventually spreads at the periphery after several hours of operation. (author)

  6. Synchronous digitization for high dynamic range lock-in amplification in beam-scanning microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Muir, Ryan D.; Sullivan, Shane Z.; Oglesbee, Robert A.; Simpson, Garth J., E-mail: gsimpson@purdue.edu [Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907 (United States)

    2014-03-15

    Digital lock-in amplification (LIA) with synchronous digitization (SD) is shown to provide significant signal to noise (S/N) and linear dynamic range advantages in beam-scanning microscopy measurements using pulsed laser sources. Direct comparisons between SD-LIA and conventional LIA in homodyne second harmonic generation measurements resulted in S/N enhancements consistent with theoretical models. SD-LIA provided notably larger S/N enhancements in the limit of low light intensities, through the smooth transition between photon counting and signal averaging developed in previous work. Rapid beam scanning instrumentation with up to video rate acquisition speeds minimized photo-induced sample damage. The corresponding increased allowance for higher laser power without sample damage is advantageous for increasing the observed signal content.

  7. Boundary driven Kawasaki process with long-range interaction: dynamical large deviations and steady states

    International Nuclear Information System (INIS)

    Mourragui, Mustapha; Orlandi, Enza

    2013-01-01

    A particle system with a single locally-conserved field (density) in a bounded interval with different densities maintained at the two endpoints of the interval is under study here. The particles interact in the bulk through a long-range potential parametrized by β⩾0 and evolve according to an exclusion rule. It is shown that the empirical particle density under the diffusive scaling solves a quasilinear integro-differential evolution equation with Dirichlet boundary conditions. The associated dynamical large deviation principle is proved. Furthermore, when β is small enough, it is also demonstrated that the empirical particle density obeys a law of large numbers with respect to the stationary measures (hydrostatic). The macroscopic particle density solves a non-local, stationary, transport equation. (paper)

  8. A terahertz EO detector with large dynamical range, high modulation depth and signal-noise ratio

    Science.gov (United States)

    Pan, Xinjian; Cai, Yi; Zeng, Xuanke; Zheng, Shuiqin; Li, Jingzhen; Xu, Shixiang

    2017-05-01

    The paper presents a novel design for terahertz (THz) free-space time domain electro-optic (EO) detection where the static birefringent phases of the two balanced arms are set close to zero but opposite to each other. Our theoretical and numerical analyses show this design has much stronger ability to cancel the optical background noise than both THz ellipsometer and traditional crossed polarizer geometry (CPG). Its optical modulation depth is about twice as high as that of traditional CPG, but about ten times as high as that of THz ellipsometer. As for the dynamical range, our improved design is comparable to the THz ellipsometer but obviously larger than the traditional CPG. Some experiments for comparing our improved CPG with traditional CPG agree well with the corresponding theoretical predictions. Our experiments also show that the splitting ratio of the used non-polarization beam splitter is critical for the performance of our design.

  9. Dynamics of r.f. production of Stellarator plasmas in the ion cyclotron range of frequency

    International Nuclear Information System (INIS)

    Moiseenko, V.E.; Lysoivan, A.I.; Kasilov, S.V.; Plyusnin, V.V.

    1995-01-01

    The present study investigated numerically the process of r.f. production of plasma in the URAGAN-3M torsatron in the frequency range below the ion cyclotron frequency (ω ci ). The dynamics of r.f. plasma build-up at the stages of neutral gas burnout and plasma heating were studied using a zero-dimensional transport code, in which the plasma confinement law was determined by large helical device scaling. Two models for input r.f. power were used. In the first case, the r.f. power absorbed by the electrons was computed by a one-dimensional r.f. code solving Maxwell's boundary problem equations. The mechanisms of electron heating through direct excitation of the slow wave (SW) by antennae as well as the conversion of fast wave (FW) into SW in the vicinity of Alfven resonance (scenario of Alfven heating) were taken into account in the computations. In the second case, an 'ideal' model of r.f. power deposition onto the electrons as a linear function of plasma density was employed. A noticeable difference in plasma production dynamics computed for these two cases was found. Better agreement with experimental data obtained from the URAGAN-3M torsatron was found for the first case resulting from combination of the one-dimensional r.f. and zero-dimensional transport codes. ((orig.))

  10. Effects of dynamic range compression on spatial selective auditory attention in normal-hearing listeners.

    Science.gov (United States)

    Schwartz, Andrew H; Shinn-Cunningham, Barbara G

    2013-04-01

    Many hearing aids introduce compressive gain to accommodate the reduced dynamic range that often accompanies hearing loss. However, natural sounds produce complicated temporal dynamics in hearing aid compression, as gain is driven by whichever source dominates at a given moment. Moreover, independent compression at the two ears can introduce fluctuations in interaural level differences (ILDs) important for spatial perception. While independent compression can interfere with spatial perception of sound, it does not always interfere with localization accuracy or speech identification. Here, normal-hearing listeners reported a target message played simultaneously with two spatially separated masker messages. We measured the amount of spatial separation required between the target and maskers for subjects to perform at threshold in this task. Fast, syllabic compression that was independent at the two ears increased the required spatial separation, but linking the compressors to provide identical gain to both ears (preserving ILDs) restored much of the deficit caused by fast, independent compression. Effects were less clear for slower compression. Percent-correct performance was lower with independent compression, but only for small spatial separations. These results may help explain differences in previous reports of the effect of compression on spatial perception of sound.

  11. An adaptive scheme for robot localization and mapping with dynamically configurable inter-beacon range measurements.

    Science.gov (United States)

    Torres-González, Arturo; Martinez-de Dios, Jose Ramiro; Ollero, Anibal

    2014-04-25

    This work is motivated by robot-sensor network cooperation techniques where sensor nodes (beacons) are used as landmarks for range-only (RO) simultaneous localization and mapping (SLAM). This paper presents a RO-SLAM scheme that actuates over the measurement gathering process using mechanisms that dynamically modify the rate and variety of measurements that are integrated in the SLAM filter. It includes a measurement gathering module that can be configured to collect direct robot-beacon and inter-beacon measurements with different inter-beacon depth levels and at different rates. It also includes a supervision module that monitors the SLAM performance and dynamically selects the measurement gathering configuration balancing SLAM accuracy and resource consumption. The proposed scheme has been applied to an extended Kalman filter SLAM with auxiliary particle filters for beacon initialization (PF-EKF SLAM) and validated with experiments performed in the CONET Integrated Testbed. It achieved lower map and robot errors (34% and 14%, respectively) than traditional methods with a lower computational burden (16%) and similar beacon energy consumption.

  12. Improving the effectiveness of detailed processing by dynamic control of processing with high sports range

    Directory of Open Access Journals (Sweden)

    Yu.V. Shapoval

    2017-12-01

    Full Text Available In this article the possibility of increasing the efficiency of the processing of parts with a diameter of up to 20 mm is analyzed, namely: vibration resistance of the cutting process at pinching due to cutting speed control in the processing, forecasting and selection of rotational frequencies, which ensure the stability of the processing system, controlling the dynamics of the process of displacement of the additional mass. The method of investigation of vibration processes during the sharpening is developed. As a result of the processing of experimental data, it was found that when an oscillatory motion is applied to the spindle rotation, the overall level of oscillation decreases, which is reflected on the quality of the treated surface. The choice of a previously known spindle rotation frequency range at which the lowest value of the oscillation amplitude of the instrument is observed in the radial direction to the detail part, allows you to increase the processing efficiency while maintaining the drawing requirements for roughness by increasing the spindle rotational speed. The combination of the node of the own forms of oscillation and the cutting zone, by dynamically controlling the fluctuations of the lathe armature due to the increase of the inertia characteristics of the machine and the reduction of the oscillation amplitude of the tool, can improve the accuracy of machining and roughness of the processed surface of the component at higher spindle speeds.

  13. Encounter success of free-ranging marine predator movements across a dynamic prey landscape.

    Science.gov (United States)

    Sims, David W; Witt, Matthew J; Richardson, Anthony J; Southall, Emily J; Metcalfe, Julian D

    2006-05-22

    Movements of wide-ranging top predators can now be studied effectively using satellite and archival telemetry. However, the motivations underlying movements remain difficult to determine because trajectories are seldom related to key biological gradients, such as changing prey distributions. Here, we use a dynamic prey landscape of zooplankton biomass in the north-east Atlantic Ocean to examine active habitat selection in the plankton-feeding basking shark Cetorhinus maximus. The relative success of shark searches across this landscape was examined by comparing prey biomass encountered by sharks with encounters by random-walk simulations of 'model' sharks. Movements of transmitter-tagged sharks monitored for 964 days (16754 km estimated minimum distance) were concentrated on the European continental shelf in areas characterized by high seasonal productivity and complex prey distributions. We show movements by adult and sub-adult sharks yielded consistently higher prey encounter rates than 90% of random-walk simulations. Behavioural patterns were consistent with basking sharks using search tactics structured across multiple scales to exploit the richest prey areas available in preferred habitats. Simple behavioural rules based on learned responses to previously encountered prey distributions may explain the high performances. This study highlights how dynamic prey landscapes enable active habitat selection in large predators to be investigated from a trophic perspective, an approach that may inform conservation by identifying critical habitat of vulnerable species.

  14. Screening variability and change of soil moisture under wide-ranging climate conditions: Snow dynamics effects.

    Science.gov (United States)

    Verrot, Lucile; Destouni, Georgia

    2015-01-01

    Soil moisture influences and is influenced by water, climate, and ecosystem conditions, affecting associated ecosystem services in the landscape. This paper couples snow storage-melting dynamics with an analytical modeling approach to screening basin-scale, long-term soil moisture variability and change in a changing climate. This coupling enables assessment of both spatial differences and temporal changes across a wide range of hydro-climatic conditions. Model application is exemplified for two major Swedish hydrological basins, Norrström and Piteälven. These are located along a steep temperature gradient and have experienced different hydro-climatic changes over the time period of study, 1950-2009. Spatially, average intra-annual variability of soil moisture differs considerably between the basins due to their temperature-related differences in snow dynamics. With regard to temporal change, the long-term average state and intra-annual variability of soil moisture have not changed much, while inter-annual variability has changed considerably in response to hydro-climatic changes experienced so far in each basin.

  15. Statistical mechanics and dynamics of solvable models with long-range interactions

    International Nuclear Information System (INIS)

    Campa, Alessandro; Dauxois, Thierry; Ruffo, Stefano

    2009-01-01

    For systems with long-range interactions, the two-body potential decays at large distances as V(r)∼1/r α , with α≤d, where d is the space dimension. Examples are: gravitational systems, two-dimensional hydrodynamics, two-dimensional elasticity, charged and dipolar systems. Although such systems can be made extensive, they are intrinsically non additive: the sum of the energies of macroscopic subsystems is not equal to the energy of the whole system. Moreover, the space of accessible macroscopic thermodynamic parameters might be non convex. The violation of these two basic properties of the thermodynamics of short-range systems is at the origin of ensemble inequivalence. In turn, this inequivalence implies that specific heat can be negative in the microcanonical ensemble, and temperature jumps can appear at microcanonical first order phase transitions. The lack of convexity allows us to easily spot regions of parameter space where ergodicity may be broken. Historically, negative specific heat had been found for gravitational systems and was thought to be a specific property of a system for which the existence of standard equilibrium statistical mechanics itself was doubted. Realizing that such properties may be present for a wider class of systems has renewed the interest in long-range interactions. Here, we present a comprehensive review of the recent advances on the statistical mechanics and out-of-equilibrium dynamics of solvable systems with long-range interactions. The core of the review consists in the detailed presentation of the concept of ensemble inequivalence, as exemplified by the exact solution, in the microcanonical and canonical ensembles, of mean-field type models. Remarkably, the entropy of all these models can be obtained using the method of large deviations. Long-range interacting systems display an extremely slow relaxation towards thermodynamic equilibrium and, what is more striking, the convergence towards quasi-stationary states. The

  16. Nonlinear mapping of the luminance in dual-layer high dynamic range displays

    Science.gov (United States)

    Guarnieri, Gabriele; Ramponi, Giovanni; Bonfiglio, Silvio; Albani, Luigi

    2009-02-01

    It has long been known that the human visual system (HVS) has a nonlinear response to luminance. This nonlinearity can be quantified using the concept of just noticeable difference (JND), which represents the minimum amplitude of a specified test pattern an average observer can discern from a uniform background. The JND depends on the background luminance following a threshold versus intensity (TVI) function. It is possible to define a curve which maps physical luminances into a perceptually linearized domain. This mapping can be used to optimize a digital encoding, by minimizing the visibility of quantization noise. It is also commonly used in medical applications to display images adapting to the characteristics of the display device. High dynamic range (HDR) displays, which are beginning to appear on the market, can display luminance levels outside the range in which most standard mapping curves are defined. In particular, dual-layer LCD displays are able to extend the gamut of luminance offered by conventional liquid crystals towards the black region; in such areas suitable and HVS-compliant luminance transformations need to be determined. In this paper we propose a method, which is primarily targeted to the extension of the DICOM curve used in medical imaging, but also has a more general application. The method can be modified in order to compensate for the ambient light, which can be significantly greater than the black level of an HDR display and consequently reduce the visibility of the details in dark areas.

  17. Sensitivity of electrospray molecular dynamics simulations to long-range Coulomb interaction models.

    Science.gov (United States)

    Mehta, Neil A; Levin, Deborah A

    2018-03-01

    Molecular dynamics (MD) electrospray simulations of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM-BF_{4}) ion liquid were performed with the goal of evaluating the influence of long-range Coulomb models on ion emission characteristics. The direct Coulomb (DC), shifted force Coulomb sum (SFCS), and particle-particle particle-mesh (PPPM) long-range Coulomb models were considered in this work. The DC method with a sufficiently large cutoff radius was found to be the most accurate approach for modeling electrosprays, but, it is computationally expensive. The Coulomb potential energy modeled by the DC method in combination with the radial electric fields were found to be necessary to generate the Taylor cone. The differences observed between the SFCS and the DC in terms of predicting the total ion emission suggest that the former should not be used in MD electrospray simulations. Furthermore, the common assumption of domain periodicity was observed to be detrimental to the accuracy of the capillary-based electrospray simulations.

  18. High Dynamic Range adaptive ΔΣ-based Focal Plane Array architecture

    KAUST Repository

    Yao, Shun

    2012-10-16

    In this paper, an Adaptive Delta-Sigma based architecture for High Dynamic Range (HDR) Focal Plane Arrays is presented. The noise shaping effect of the Delta-Sigma modulation in the low end, and the distortion noise induced in the high end of Photo-diode current were analyzed in detail. The proposed architecture can extend the DR for about 20N log2 dB at the high end of Photo-diode current with an N bit Up-Down counter. At the low end, it can compensate for the larger readout noise by employing Extended Counting. The Adaptive Delta-Sigma architecture employing a 4-bit Up-Down counter achieved about 160dB in the DR, with a Peak SNR (PSNR) of 80dB at the high end. Compared to the other HDR architectures, the Adaptive Delta-Sigma based architecture provides the widest DR with the best SNR performance in the extended range.

  19. Determination of boron over a large dynamic range by prompt-gamma activation analysis

    International Nuclear Information System (INIS)

    Harrison, R.K.; Landsberger, S.

    2009-01-01

    An evaluation of the PGAA method for the determination of boron across a wide dynamic range of concentrations was performed for trace levels up to 5 wt.% boron. This range encompasses a transition from neutron transparency to significant self- shielding conditions. To account for self-shielding, several PGAA techniques were employed. First, a calibration curve was developed in which a set of boron standards was tested and the count rate to boron mass curve was determined. This set of boron measurements was compared with an internal standard self-shielding correction method and with a method for determining composition using PGAA peak ratios. The advantages and disadvantages of each method are analyzed. The boron concentrations of several laboratory-grade chemicals and standard reference materials were measured with each method and compared. The evaluation of the boron content of nanocrystalline transition metals prepared with a boron-containing reducing agent was also performed with each of the methods tested. Finally, the k 0 method was used for non-destructive measurement of boron in catalyst materials for the characterization of new non-platinum fuel cell catalysts.

  20. Long-range correlations and fractal dynamics in C. elegans: Changes with aging and stress

    Science.gov (United States)

    Alves, Luiz G. A.; Winter, Peter B.; Ferreira, Leonardo N.; Brielmann, Renée M.; Morimoto, Richard I.; Amaral, Luís A. N.

    2017-08-01

    Reduced motor control is one of the most frequent features associated with aging and disease. Nonlinear and fractal analyses have proved to be useful in investigating human physiological alterations with age and disease. Similar findings have not been established for any of the model organisms typically studied by biologists, though. If the physiology of a simpler model organism displays the same characteristics, this fact would open a new research window on the control mechanisms that organisms use to regulate physiological processes during aging and stress. Here, we use a recently introduced animal-tracking technology to simultaneously follow tens of Caenorhabdits elegans for several hours and use tools from fractal physiology to quantitatively evaluate the effects of aging and temperature stress on nematode motility. Similar to human physiological signals, scaling analysis reveals long-range correlations in numerous motility variables, fractal properties in behavioral shifts, and fluctuation dynamics over a wide range of timescales. These properties change as a result of a superposition of age and stress-related adaptive mechanisms that regulate motility.

  1. Secondary sympatry caused by range expansion informs on the dynamics of microendemism in a biodiversity hotspot.

    Directory of Open Access Journals (Sweden)

    Romain Nattier

    Full Text Available Islands are bounded areas where high endemism is explained either by allopatric speciation through the fragmentation of the limited amount of space available, or by sympatric speciation and accumulation of daughter species. Most empirical evidence point out the dominant action of allopatric speciation. We evaluate this general view by looking at a case study where sympatric speciation is suspected. We analyse the mode, tempo and geography of speciation in Agnotecous, a cricket genus endemic to New Caledonia showing a generalized pattern of sympatry between species making sympatric speciation plausible. We obtained five mitochondrial and five nuclear markers (6.8 kb from 37 taxa corresponding to 17 of the 21 known extant species of Agnotecous, and including several localities per species, and we conducted phylogenetic and dating analyses. Our results suggest that the diversification of Agnotecous occurred mostly through allopatric speciation in the last 10 Myr. Highly microendemic species are the most recent ones (<2 Myr and current sympatry is due to secondary range expansion after allopatric speciation. Species distribution should then be viewed as a highly dynamic process and extreme microendemism only as a temporary situation. We discuss these results considering the influence of climatic changes combined with intricate soil diversity and mountain topography. A complex interplay between these factors could have permitted repeated speciation events and range expansion.

  2. Exploring the dynamics of phase separation in colloid-polymer mixtures with long range attraction.

    Science.gov (United States)

    Sabin, Juan; Bailey, Arthur E; Frisken, Barbara J

    2016-06-28

    We have studied the kinetics of phase separation and gel formation in a low-dispersity colloid - non-adsorbing polymer system with long range attraction using small-angle light scattering. This system exhibits two-phase and three-phase coexistence of gas, liquid and crystal phases when the strength of attraction is between 2 and 4kBT and gel phases when the strength of attraction is increased. For those samples that undergo macroscopic phase separation, whether to gas-crystal, gas-liquid or gas-liquid-crystal coexistence, we observe dynamic scaling of the structure factor and growth of a characteristic length scale that behaves as expected for phase separation in fluids. In samples that gel, the power law associated with the growth of the dominant length scale is not equal to 1/3, but appears to depend mainly on the strength of attraction, decreasing from 1/3 for samples near the coexistence region to 1/27 at 8kBT, over a wide range of colloid and polymer concentrations.

  3. Shack-Hartmann centroid detection method based on high dynamic range imaging and normalization techniques

    International Nuclear Information System (INIS)

    Vargas, Javier; Gonzalez-Fernandez, Luis; Quiroga, Juan Antonio; Belenguer, Tomas

    2010-01-01

    In the optical quality measuring process of an optical system, including diamond-turning components, the use of a laser light source can produce an undesirable speckle effect in a Shack-Hartmann (SH) CCD sensor. This speckle noise can deteriorate the precision and accuracy of the wavefront sensor measurement. Here we present a SH centroid detection method founded on computer-based techniques and capable of measurement in the presence of strong speckle noise. The method extends the dynamic range imaging capabilities of the SH sensor through the use of a set of different CCD integration times. The resultant extended range spot map is normalized to accurately obtain the spot centroids. The proposed method has been applied to measure the optical quality of the main optical system (MOS) of the mid-infrared instrument telescope smulator. The wavefront at the exit of this optical system is affected by speckle noise when it is illuminated by a laser source and by air turbulence because it has a long back focal length (3017 mm). Using the proposed technique, the MOS wavefront error was measured and satisfactory results were obtained.

  4. A STEP TOWARDS DYNAMIC SCENE ANALYSIS WITH ACTIVE MULTI-VIEW RANGE IMAGING SYSTEMS

    Directory of Open Access Journals (Sweden)

    M. Weinmann

    2012-07-01

    Full Text Available Obtaining an appropriate 3D description of the local environment remains a challenging task in photogrammetric research. As terrestrial laser scanners (TLSs perform a highly accurate, but time-dependent spatial scanning of the local environment, they are only suited for capturing static scenes. In contrast, new types of active sensors provide the possibility of simultaneously capturing range and intensity information by images with a single measurement, and the high frame rate also allows for capturing dynamic scenes. However, due to the limited field of view, one observation is not sufficient to obtain a full scene coverage and therefore, typically, multiple observations are collected from different locations. This can be achieved by either placing several fixed sensors at different known locations or by using a moving sensor. In the latter case, the relation between different observations has to be estimated by using information extracted from the captured data and then, a limited field of view may lead to problems if there are too many moving objects within it. Hence, a moving sensor platform with multiple and coupled sensor devices offers the advantages of an extended field of view which results in a stabilized pose estimation, an improved registration of the recorded point clouds and an improved reconstruction of the scene. In this paper, a new experimental setup for investigating the potentials of such multi-view range imaging systems is presented which consists of a moving cable car equipped with two synchronized range imaging devices. The presented setup allows for monitoring in low altitudes and it is suitable for getting dynamic observations which might arise from moving cars or from moving pedestrians. Relying on both 3D geometry and 2D imagery, a reliable and fully automatic approach for co-registration of captured point cloud data is presented which is essential for a high quality of all subsequent tasks. The approach involves using

  5. Calibration and assessment of channel-specific biases in microarray data with extended dynamical range.

    Science.gov (United States)

    Bengtsson, Henrik; Jönsson, Göran; Vallon-Christersson, Johan

    2004-11-12

    Non-linearities in observed log-ratios of gene expressions, also known as intensity dependent log-ratios, can often be accounted for by global biases in the two channels being compared. Any step in a microarray process may introduce such offsets and in this article we study the biases introduced by the microarray scanner and the image analysis software. By scanning the same spotted oligonucleotide microarray at different photomultiplier tube (PMT) gains, we have identified a channel-specific bias present in two-channel microarray data. For the scanners analyzed it was in the range of 15-25 (out of 65,535). The observed bias was very stable between subsequent scans of the same array although the PMT gain was greatly adjusted. This indicates that the bias does not originate from a step preceding the scanner detector parts. The bias varies slightly between arrays. When comparing estimates based on data from the same array, but from different scanners, we have found that different scanners introduce different amounts of bias. So do various image analysis methods. We propose a scanning protocol and a constrained affine model that allows us to identify and estimate the bias in each channel. Backward transformation removes the bias and brings the channels to the same scale. The result is that systematic effects such as intensity dependent log-ratios are removed, but also that signal densities become much more similar. The average scan, which has a larger dynamical range and greater signal-to-noise ratio than individual scans, can then be obtained. The study shows that microarray scanners may introduce a significant bias in each channel. Such biases have to be calibrated for, otherwise systematic effects such as intensity dependent log-ratios will be observed. The proposed scanning protocol and calibration method is simple to use and is useful for evaluating scanner biases or for obtaining calibrated measurements with extended dynamical range and better precision. The

  6. Reliable and repeatable characterization of optical streak cameras

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  7. Reliable and Repeatable Characterization of Optical Streak Cameras

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  8. Reliable and Repeatable Characterization of Optical Streak Cameras

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-10-31

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

  9. Reliable and Repeatable Characterication of Optical Streak Cameras

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-06

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

  10. Reliable and Repeatable Characterization of Optical Streak Cameras

    International Nuclear Information System (INIS)

    Michael R. Charest, Peter Torres III, Christopher Silbernagel

    2008-01-01

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

  11. An open-source, FireWire camera-based, Labview-controlled image acquisition system for automated, dynamic pupillometry and blink detection.

    Science.gov (United States)

    de Souza, John Kennedy Schettino; Pinto, Marcos Antonio da Silva; Vieira, Pedro Gabrielle; Baron, Jerome; Tierra-Criollo, Carlos Julio

    2013-12-01

    The dynamic, accurate measurement of pupil size is extremely valuable for studying a large number of neuronal functions and dysfunctions. Despite tremendous and well-documented progress in image processing techniques for estimating pupil parameters, comparatively little work has been reported on practical hardware issues involved in designing image acquisition systems for pupil analysis. Here, we describe and validate the basic features of such a system which is based on a relatively compact, off-the-shelf, low-cost FireWire digital camera. We successfully implemented two configurable modes of video record: a continuous mode and an event-triggered mode. The interoperability of the whole system is guaranteed by a set of modular software components hosted on a personal computer and written in Labview. An offline analysis suite of image processing algorithms for automatically estimating pupillary and eyelid parameters were assessed using data obtained in human subjects. Our benchmark results show that such measurements can be done in a temporally precise way at a sampling frequency of up to 120 Hz and with an estimated maximum spatial resolution of 0.03 mm. Our software is made available free of charge to the scientific community, allowing end users to either use the software as is or modify it to suit their own needs. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. Comparison of Corneal Deformation Parameters in Keratoconic and Normal Eyes Using a Non-contact Tonometer With a Dynamic Ultra-High-Speed Scheimpflug Camera.

    Science.gov (United States)

    Mercer, Ryan N; Waring, George O; Roberts, Cynthia J; Jhanji, Vishal; Wang, Yumeng; Filho, Joao S; Hemings, Richard A; Rocha, Karolinne M

    2017-09-01

    To evaluate and compare biomechanical properties in normal and keratoconic eyes using a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (Corvis ST; Oculus Optikgeräte GmbH, Wetzlar, Germany). This retrospective study evaluated 89 eyes (47 normal, 42 keratoconic) and a validation arm of 72 eyes (33 normal, 39 keratoconic) using the Corvis ST. A diagnosis of keratoconus was established by clinical findings confirmed by topography and tomography. Dynamic corneal response parameters collected by the Corvis ST (A1 velocity, deformation amplitude [DA], DA Ratio Max 1mm, and Max Inverse Radius) and a stiffness parameter at first applanation (SP-A1) were incorporated into a novel logistic regression equation (DCR index). Area under the receiver operating curve (AUC) was used to assess the sensitivity and specificity of the DCR index. DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1 were each found to be statistically significantly different between normal and keratoconic eyes (Mann-Whitney test [independent samples]; P = .0077, < .0001, < .0001, and < .0001, respectively; significance level: P < .05). DCR index demonstrated high sensitivity, specificity, and overall correct detection rate (92.9%, 95.7%, and 94.4%, respectively; AUC = 98.5). The sensitivity and overall correct detection rate improved when eyes with Topographical Keratoconus Classification grades (TKC) greater than 0 were reevaluated (from 92.9% to 96.6% and from 94.4% to 96.1%, respectively). Combining multiple biomechanical parameters (A1 velocity, DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1) into a logistic regression equation allows for high sensitivity and specificity for distinguishing keratoconic from normal eyes. [J Refract Surg. 2017;33(9):625-631.]. Copyright 2017, SLACK Incorporated.

  13. Extended-Range High-Resolution Dynamical Downscaling over a Continental-Scale Domain

    Science.gov (United States)

    Husain, S. Z.; Separovic, L.; Yu, W.; Fernig, D.

    2014-12-01

    High-resolution mesoscale simulations, when applied for downscaling meteorological fields over large spatial domains and for extended time periods, can provide valuable information for many practical application scenarios including the weather-dependent renewable energy industry. In the present study, a strategy has been proposed to dynamically downscale coarse-resolution meteorological fields from Environment Canada's regional analyses for a period of multiple years over the entire Canadian territory. The study demonstrates that a continuous mesoscale simulation over the entire domain is the most suitable approach in this regard. Large-scale deviations in the different meteorological fields pose the biggest challenge for extended-range simulations over continental scale domains, and the enforcement of the lateral boundary conditions is not sufficient to restrict such deviations. A scheme has therefore been developed to spectrally nudge the simulated high-resolution meteorological fields at the different model vertical levels towards those embedded in the coarse-resolution driving fields derived from the regional analyses. A series of experiments were carried out to determine the optimal nudging strategy including the appropriate nudging length scales, nudging vertical profile and temporal relaxation. A forcing strategy based on grid nudging of the different surface fields, including surface temperature, soil-moisture, and snow conditions, towards their expected values obtained from a high-resolution offline surface scheme was also devised to limit any considerable deviation in the evolving surface fields due to extended-range temporal integrations. The study shows that ensuring large-scale atmospheric similarities helps to deliver near-surface statistical scores for temperature, dew point temperature and horizontal wind speed that are better or comparable to the operational regional forecasts issued by Environment Canada. Furthermore, the meteorological fields

  14. Long Range Polymer Chain Dynamics of Highly Flexible Polysiloxane in Solution Probed by Pyrene Excimer Fluorescence

    Directory of Open Access Journals (Sweden)

    Janine L. Thoma

    2018-03-01

    Full Text Available A poly(dimethylsiloxane-co-(3-aminopropylmethylsiloxane polymer (PDMS with 20.3 mol % of (3-aminopropylmethyl siloxane monomer has been labeled randomly with 1-pyreneacetyl groups to generate a series of polysiloxanes (Py-PDMS with pyrenyl contents ranging from 0.7 mol % to 5.2 mol % of the total number of structural units. The remainder of the amino groups were acetylated to avoid intra-chain quenching of the excited singlet states of pyrene via exciplex formation with free amino groups while allowing the formation of excimers to proceed. The fluorescence spectra and temporal decays of the Py-PDMS samples were acquired in tetrahydrofuran (THF, N,N-dimethylformamide (DMF, and dioxane. blob, the average rate constant for intra-chain pyrene excimer formation, was determined from the analysis of the fluorescence decays. blob was found to equal 1.16 (±0.13 × 109, 1.14 (±0.12 × 109, and 0.99 (±0.10 × 109 s−1 in THF, DMF, and dioxane, respectively, at room temperature. They are the largest values found to date for any polymeric backbone in these solvents. The qualitative relationship found here between blob and the chemical structures of the polymers indicates that the luminescence characteristics of randomly labeled polymers is a very useful method to probe the long range dynamics of chains of almost any polymer that is amenable to substitution by a lumophore.

  15. A nonrecursive order N preconditioned conjugate gradient: Range space formulation of MDOF dynamics

    Science.gov (United States)

    Kurdila, Andrew J.

    1990-01-01

    While excellent progress has been made in deriving algorithms that are efficient for certain combinations of system topologies and concurrent multiprocessing hardware, several issues must be resolved to incorporate transient simulation in the control design process for large space structures. Specifically, strategies must be developed that are applicable to systems with numerous degrees of freedom. In addition, the algorithms must have a growth potential in that they must also be amenable to implementation on forthcoming parallel system architectures. For mechanical system simulation, this fact implies that algorithms are required that induce parallelism on a fine scale, suitable for the emerging class of highly parallel processors; and transient simulation methods must be automatically load balancing for a wider collection of system topologies and hardware configurations. These problems are addressed by employing a combination range space/preconditioned conjugate gradient formulation of multi-degree-of-freedom dynamics. The method described has several advantages. In a sequential computing environment, the method has the features that: by employing regular ordering of the system connectivity graph, an extremely efficient preconditioner can be derived from the 'range space metric', as opposed to the system coefficient matrix; because of the effectiveness of the preconditioner, preliminary studies indicate that the method can achieve performance rates that depend linearly upon the number of substructures, hence the title 'Order N'; and the method is non-assembling. Furthermore, the approach is promising as a potential parallel processing algorithm in that the method exhibits a fine parallel granularity suitable for a wide collection of combinations of physical system topologies/computer architectures; and the method is easily load balanced among processors, and does not rely upon system topology to induce parallelism.

  16. Orthostatic stress is necessary to maintain the dynamic range of cardiovascular control in space

    Science.gov (United States)

    Baisch, J. F.; Wolfram, G.; Beck, L.; Drummer, C.; Stormer, I.; Buckey, J.; Blomqvist, G.

    2000-01-01

    In the upright position, gravity fills the low-pressure systems of human circulation with blood and interstitial fluid in the sections below the diaphragm. Without gravity one pressure component in the vessels disappears and the relationship between hydrostatic pressure and oncotic pressure, which regulates fluid passage across the capillary endothelium in the terminal vascular bed, shifts constantly. The visible consequences of this are a puffy face and "bird" legs. The plasma volume shrinks in space and the range of cardiovascular control is reduced. When they stand up for the first time after landing, 30-50% of astronauts suffer from orthostatic intolerance. It remains unclear whether microgravity impairs cardiovascular reflexes, or whether it is the altered volume status that causes the cardiovascular instability following space flight. Lower body negative pressure was used in several space missions to stimulate the cardiovascular reflexes before, during and after a space flight. The results show that cardiovascular reflexes are maintained in microgravity. However, the astronauts' volume status changed in space, towards a volume-retracted state, as measurements of fluid-regulating hormones have shown. It can be hypothesized that the control of circulation and body fluid homeostasis in humans is adapted to their upright posture in the Earth's gravitational field. Autonomic control regulates fluid distribution to maintain the blood pressure in that posture, which most of us have to cope with for two-thirds of the day. A determined amount of interstitial volume is necessary to maintain the dynamic range of cardiovascular control in the upright posture; otherwise orthostatic intolerance may occur more often.

  17. Realistic camera noise modeling with application to improved HDR synthesis

    Science.gov (United States)

    Goossens, Bart; Luong, Hiêp; Aelterman, Jan; Pižurica, Aleksandra; Philips, Wilfried

    2012-12-01

    Due to the ongoing miniaturization of digital camera sensors and the steady increase of the "number of megapixels", individual sensor elements of the camera become more sensitive to noise, even deteriorating the final image quality. To go around this problem, sophisticated processing algorithms in the devices, can help to maximally exploit the knowledge on the sensor characteristics (e.g., in terms of noise), and offer a better image reconstruction. Although a lot of research focuses on rather simplistic noise models, such as stationary additive white Gaussian noise, only limited attention has gone to more realistic digital camera noise models. In this article, we first present a digital camera noise model that takes several processing steps in the camera into account, such as sensor signal amplification, clipping, post-processing,.. We then apply this noise model to the reconstruction problem of high dynamic range (HDR) images from a small set of low dynamic range (LDR) exposures of a static scene. In literature, HDR reconstruction is mostly performed by computing a weighted average, in which the weights are directly related to the observer pixel intensities of the LDR image. In this work, we derive a Bayesian probabilistic formulation of a weighting function that is near-optimal in the MSE sense (or SNR sense) of the reconstructed HDR image, by assuming exponentially distributed irradiance values. We define the weighting function as the probability that the observed pixel intensity is approximately unbiased. The weighting function can be directly computed based on the noise model parameters, which gives rise to different symmetric and asymmetric shapes when electronic noise or photon noise is dominant. We also explain how to deal with the case that some of the noise model parameters are unknown and explain how the camera response function can be estimated using the presented noise model. Finally, experimental results are provided to support our findings.

  18. Utilizing multiple state variables to improve the dynamic range of analog switching in a memristor

    International Nuclear Information System (INIS)

    Jeong, YeonJoo; Kim, Sungho; Lu, Wei D.

    2015-01-01

    Memristors and memristive systems have been extensively studied for data storage and computing applications such as neuromorphic systems. To act as synapses in neuromorphic systems, the memristor needs to exhibit analog resistive switching (RS) behavior with incremental conductance change. In this study, we show that the dynamic range of the analog RS behavior can be significantly enhanced in a tantalum-oxide-based memristor. By controlling different state variables enabled by different physical effects during the RS process, the gradual filament expansion stage can be selectively enhanced without strongly affecting the abrupt filament length growth stage. Detailed physics-based modeling further verified the observed experimental effects and revealed the roles of oxygen vacancy drift and diffusion processes, and how the diffusion process can be selectively enhanced during the filament expansion stage. These findings lead to more desirable and reliable memristor behaviors for analog computing applications. Additionally, the ability to selectively control different internal physical processes demonstrated in the current study provides guidance for continued device optimization of memristor devices in general

  19. Sub-Airy disk angular resolution with high dynamic range in the near-infrared

    Directory of Open Access Journals (Sweden)

    Richichi A.

    2011-07-01

    Full Text Available Lunar occultations (LO are a simple and effective high angular resolution method, with minimum requirements in instrumentation and telescope time. They rely on the analysis of the diffraction fringes created by the lunar limb. The diffraction phenomen occurs in space, and as a result LO are highly insensitive to most of the degrading effects that limit the performance of traditional single telescope and long-baseline interferometric techniques used for direct detection of faint, close companions to bright stars. We present very recent results obtained with the technique of lunar occultations in the near-IR, showing the detection of companions with very high dynamic range as close as few milliarcseconds to the primary star. We discuss the potential improvements that could be made, to increase further the current performance. Of course, LO are fixed-time events applicable only to sources which happen to lie on the Moon’s apparent orbit. However, with the continuously increasing numbers of potential exoplanets and brown dwarfs beign discovered, the frequency of such events is not negligible. I will list some of the most favorable potential LO in the near future, to be observed from major observatories.

  20. Increased Alpha-Rhythm Dynamic Range Promotes Recovery from Visuospatial Neglect: A Neurofeedback Study

    Directory of Open Access Journals (Sweden)

    Tomas Ros

    2017-01-01

    Full Text Available Despite recent attempts to use electroencephalogram (EEG neurofeedback (NFB as a tool for rehabilitation of motor stroke, its potential for improving neurological impairments of attention—such as visuospatial neglect—remains underexplored. It is also unclear to what extent changes in cortical oscillations contribute to the pathophysiology of neglect, or its recovery. Utilizing EEG-NFB, we sought to causally manipulate alpha oscillations in 5 right-hemisphere stroke patients in order to explore their role in visuospatial neglect. Patients trained to reduce alpha oscillations from their right posterior parietal cortex (rPPC for 20 minutes daily, over 6 days. Patients demonstrated successful NFB learning between training sessions, denoted by improved regulation of alpha oscillations from rPPC. We observed a significant negative correlation between visuospatial search deficits (i.e., cancellation test and reestablishment of spontaneous alpha-rhythm dynamic range (i.e., its amplitude variability. Our findings support the use of NFB as a tool for investigating neuroplastic recovery after stroke and suggest reinstatement of intact parietal alpha oscillations as a promising target for reversing attentional deficits. Specifically, we demonstrate for the first time the feasibility of EEG-NFB in neglect patients and provide evidence that targeting alpha amplitude variability might constitute a valuable marker for clinical symptoms and self-regulation.

  1. Realization of High Dynamic Range Imaging in the GLORIA Network and Its Effect on Astronomical Measurement

    Directory of Open Access Journals (Sweden)

    Stanislav Vítek

    2016-01-01

    Full Text Available Citizen science project GLORIA (GLObal Robotic-telescopes Intelligent Array is a first free- and open-access network of robotic telescopes in the world. It provides a web-based environment where users can do research in astronomy by observing with robotic telescopes and/or by analyzing data that other users have acquired with GLORIA or from other free-access databases. Network of 17 telescopes allows users to control selected telescopes in real time or schedule any more demanding observation. This paper deals with new opportunity that GLORIA project provides to teachers and students of various levels of education. At the moment, there are prepared educational materials related to events like Sun eclipse (measuring local atmosphere changes, Aurora Borealis (calculation of Northern Lights height, or transit of Venus (measurement of the Earth-Sun distance. Student should be able to learn principles of CCD imaging, spectral analysis, basic calibration like dark frames subtraction, or advanced methods of noise suppression. Every user of the network can design his own experiment. We propose advanced experiment aimed at obtaining astronomical image data with high dynamic range. We also introduce methods of objective image quality evaluation in order to discover how HDR methods are affecting astronomical measurements.

  2. Dynamic magnetic susceptibility of systems with long-range magnetic order

    International Nuclear Information System (INIS)

    Vannette, Matthew Dano

    2009-01-01

    The utility of the TDR as an instrument in the study of magnetically ordered materials has been expanded beyond the simple demonstration purposes. Results of static applied magnetic field dependent measurements of the dynamic magnetic susceptibility, ?, of various ferromagnetic (FM) and antiferromagnetic (AFM) materials showing a range of transition temperatures (1-800 K) are presented. Data was collected primarily with a tunnel diode resonator (TDR) at different radio-frequencies (∼10-30 MHz). In the vicinity of TC local moment ferromagnets show a very sharp, narrow peak in ? which is suppressed in amplitude and shifted to higher temperatures as the static bias field is increased. Unexpectedly, critical scaling analysis fails for these data. It is seen that these data are frequency dependent, however there is no simple method whereby measurement frequency can be changed in a controllable fashion. In contrast, itinerant ferromagnets show a broad maximum in ? well below TC which is suppressed and shifts to lower temperatures as the dc bias field is increased. The data on itinerant ferromagnets is fitted to a semi-phenomenological model that suggests the sample response is dominated by the uncompensated minority spins in the conduction band. Concluding remarks suggest possible scenarios to achieve frequency resolved data using the TDR as well as other fields in which the apparatus may be exploited.

  3. Design, commissioning and operational results of wide dynamic range BPM switched electrode electronics

    International Nuclear Information System (INIS)

    Powers, T.; Doolittle, L.; Ursic, R.; Wagner, J.

    1997-01-01

    The Continuous Electron Beam Accelerator Facility (CEBAF) is a high-intensity, continuous-wave electron accelerator for nuclear physics. Total acceleration of 4 GeV is achieved by recirculating the beam through two 400-MeV linacs. The operating currents over which the linac beam position monitoring system must meet specifications are 1 μA to 1000 μA. A system was developed in 1994 and installed in the spring of 1995 that switches four electrode signals at 120 kHz through two signal-conditioning chains that use computer-controlled variable gain amplifiers with a dynamic range greater than 80 dB. The system timing was tuned to the machine recirculation period of 4.2 μs so that components of the multipass beam could be resolved in the linacs. Other features of this VME-based system include long-term stability and high-speed data acquisition, which make it suitable for use as both a time-domain diagnostic tool and as part of a variety of beam feedback systems. The computer interface has enough control over the hardware to make a thorough self-calibration and verification-of-operation routine possible. copyright 1997 American Institute of Physics

  4. Spatially dynamic recurrent information flow across long-range dorsal motor network encodes selective motor goals.

    Science.gov (United States)

    Yoo, Peter E; Hagan, Maureen A; John, Sam E; Opie, Nicholas L; Ordidge, Roger J; O'Brien, Terence J; Oxley, Thomas J; Moffat, Bradford A; Wong, Yan T

    2018-03-08

    Performing voluntary movements involves many regions of the brain, but it is unknown how they work together to plan and execute specific movements. We recorded high-resolution ultra-high-field blood-oxygen-level-dependent signal during a cued ankle-dorsiflexion task. The spatiotemporal dynamics and the patterns of task-relevant information flow across the dorsal motor network were investigated. We show that task-relevant information appears and decays earlier in the higher order areas of the dorsal motor network then in the primary motor cortex. Furthermore, the results show that task-relevant information is encoded in general initially, and then selective goals are subsequently encoded in specifics subregions across the network. Importantly, the patterns of recurrent information flow across the network vary across different subregions depending on the goal. Recurrent information flow was observed across all higher order areas of the dorsal motor network in the subregions encoding for the current goal. In contrast, only the top-down information flow from the supplementary motor cortex to the frontoparietal regions, with weakened recurrent information flow between the frontoparietal regions and bottom-up information flow from the frontoparietal regions to the supplementary cortex were observed in the subregions encoding for the opposing goal. We conclude that selective motor goal encoding and execution rely on goal-dependent differences in subregional recurrent information flow patterns across the long-range dorsal motor network areas that exhibit graded functional specialization. © 2018 Wiley Periodicals, Inc.

  5. Cascadia, an ultracompact seismic instrument with over 200dB of dynamic range

    Science.gov (United States)

    Parker, Tim; Devanney, Peter; Bainbridge, Geoff; Townsend, Bruce

    2017-04-01

    Integration of geophysical instrumentation is clearly a way to lower overall station cost, make installations less complex, reduce installation time, increase station utility and value to a wider group of researchers, data miners and monitoring groups. Initiatives to expand early earthquake warning networks and observatories can use these savings for increasing station density. Integration of mature instrument systems such as broadband sensors and accelerometers used in strong motion studies has to be done with care to preserve the low noise and low frequency performance while providing over 200dB of dynamic range. Understanding the instrument complexities and deployment challenges allows the engineering teams to optimize the packaging to make installation and servicing cost effective, simple, routine and ultimately more reliable. We discuss early results from testing both in the lab and in the field of a newly released instrument called the Cascadia that integrates a broadband seismometer with a class A (USGS rating) accelerometer in a small stainless steel sonde suited for dense arrays in either ad hoc direct bury field deployments or in observatory quality shallow boreholes.

  6. A Hybrid Shared-Memory Parallel Max-Tree Algorithm for Extreme Dynamic-Range Images.

    Science.gov (United States)

    Moschini, Ugo; Meijster, Arnold; Wilkinson, Michael H F

    2018-03-01

    Max-trees, or component trees, are graph structures that represent the connected components of an image in a hierarchical way. Nowadays, many application fields rely on images with high-dynamic range or floating point values. Efficient sequential algorithms exist to build trees and compute attributes for images of any bit depth. However, we show that the current parallel algorithms perform poorly already with integers at bit depths higher than 16 bits per pixel. We propose a parallel method combining the two worlds of flooding and merging max-tree algorithms. First, a pilot max-tree of a quantized version of the image is built in parallel using a flooding method. Later, this structure is used in a parallel leaf-to-root approach to compute efficiently the final max-tree and to drive the merging of the sub-trees computed by the threads. We present an analysis of the performance both on simulated and actual 2D images and 3D volumes. Execution times are about better than the fastest sequential algorithm and speed-up goes up to on 64 threads.

  7. Intelligent Energy Management Control for Extended Range Electric Vehicles Based on Dynamic Programming and Neural Network

    Directory of Open Access Journals (Sweden)

    Lihe Xi

    2017-11-01

    Full Text Available The extended range electric vehicle (EREV can store much clean energy from the electric grid when it arrives at the charging station with lower battery energy. Consuming minimum gasoline during the trip is a common goal for most energy management controllers. To achieve these objectives, an intelligent energy management controller for EREV based on dynamic programming and neural networks (IEMC_NN is proposed. The power demand split ratio between the extender and battery are optimized by DP, and the control objectives are presented as a cost function. The online controller is trained by neural networks. Three trained controllers, constructing the controller library in IEMC_NN, are obtained from training three typical lengths of the driving cycle. To determine an appropriate NN controller for different driving distance purposes, the selection module in IEMC_NN is developed based on the remaining battery energy and the driving distance to the charging station. Three simulation conditions are adopted to validate the performance of IEMC_NN. They are target driving distance information, known and unknown, changing the destination during the trip. Simulation results using these simulation conditions show that the IEMC_NN had better fuel economy than the charging deplete/charging sustain (CD/CS algorithm. More significantly, with known driving distance information, the battery SOC controlled by IEMC_NN can just reach the lower bound as the EREV arrives at the charging station, which was also feasible when the driver changed the destination during the trip.

  8. Towards high dynamic range extensions of HEVC: subjective evaluation of potential coding technologies

    Science.gov (United States)

    Hanhart, Philippe; Řeřábek, Martin; Ebrahimi, Touradj

    2015-09-01

    This paper reports the details and results of the subjective evaluations conducted at EPFL to evaluate the responses to the Call for Evidence (CfE) for High Dynamic Range (HDR) and Wide Color Gamut (WCG) Video Coding issued by Moving Picture Experts Group (MPEG). The CfE on HDR/WCG Video Coding aims to explore whether the coding efficiency and/or the functionality of the current version of HEVC standard can be signi_cantly improved for HDR and WCG content. In total, nine submissions, five for Category 1 and four for Category 3a, were compared to the HEVC Main 10 Profile based Anchor. More particularly, five HDR video contents, compressed at four bit rates by each proponent responding to the CfE, were used in the subjective evaluations. Further, the side-by-side presentation methodology was used for the subjective experiment to discriminate small differences between the Anchor and proponents. Subjective results shows that the proposals provide evidence that the coding efficiency can be improved in a statistically noticeable way over MPEG CfE Anchors in terms of perceived quality within the investigated content. The paper further benchmarks the selected objective metrics based on their correlations with the subjective ratings. It is shown that PSNR-DE1000, HDRVDP- 2, and PSNR-Lx can reliably detect visible differences between the proposed encoding solutions and current HEVC standard.

  9. Establishing imaging sensor specifications for digital still cameras

    Science.gov (United States)

    Kriss, Michael A.

    2007-02-01

    Digital Still Cameras, DSCs, have now displaced conventional still cameras in most markets. The heart of a DSC is thought to be the imaging sensor, be it Full Frame CCD, and Interline CCD, a CMOS sensor or the newer Foveon buried photodiode sensors. There is a strong tendency by consumers to consider only the number of mega-pixels in a camera and not to consider the overall performance of the imaging system, including sharpness, artifact control, noise, color reproduction, exposure latitude and dynamic range. This paper will provide a systematic method to characterize the physical requirements of an imaging sensor and supporting system components based on the desired usage. The analysis is based on two software programs that determine the "sharpness", potential for artifacts, sensor "photographic speed", dynamic range and exposure latitude based on the physical nature of the imaging optics, sensor characteristics (including size of pixels, sensor architecture, noise characteristics, surface states that cause dark current, quantum efficiency, effective MTF, and the intrinsic full well capacity in terms of electrons per square centimeter). Examples will be given for consumer, pro-consumer, and professional camera systems. Where possible, these results will be compared to imaging system currently on the market.

  10. A Low-Power High-Dynamic-Range Receiver System for In-Probe 3-D Ultrasonic Imaging.

    Science.gov (United States)

    Attarzadeh, Hourieh; Xu, Ye; Ytterdal, Trond

    2017-10-01

    In this paper, a dual-mode low-power, high dynamic-range receiver circuit is designed for the interface with a capacitive micromachined ultrasonic transducer. The proposed ultrasound receiver chip enables the development of an in-probe digital beamforming imaging system. The flexibility of having two operation modes offers a high dynamic range with minimum power sacrifice. A prototype of the chip containing one receive channel, with one variable transimpedance amplifier (TIA) and one analog to digital converter (ADC) circuit is implemented. Combining variable gain TIA functionality with ADC gain settings achieves an enhanced overall high dynamic range, while low power dissipation is maintained. The chip is designed and fabricated in a 65 nm standard CMOS process technology. The test chip occupies an area of 76[Formula: see text] 170 [Formula: see text]. A total average power range of 60-240 [Formula: see text] for a sampling frequency of 30 MHz, and a center frequency of 5 MHz is measured. An instantaneous dynamic range of 50.5 dB with an overall dynamic range of 72 dB is obtained from the receiver circuit.

  11. Neutron imaging system based on a video camera

    International Nuclear Information System (INIS)

    Dinca, M.

    2004-01-01

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

  12. Microspatial ecotone dynamics at a shifting range limit: plant-soil variation across salt marsh-mangrove interfaces.

    Science.gov (United States)

    Yando, E S; Osland, M J; Hester, M W

    2018-05-01

    Ecotone dynamics and shifting range limits can be used to advance our understanding of the ecological implications of future range expansions in response to climate change. In the northern Gulf of Mexico, the salt marsh-mangrove ecotone is an area where range limits and ecotone dynamics can be studied in tandem as recent decreases in winter temperature extremes have allowed for mangrove expansion at the expense of salt marsh. In this study, we assessed aboveground and belowground plant-soil dynamics across the salt marsh-mangrove ecotone quantifying micro-spatial patterns in horizontal extent. Specifically, we studied vegetation and rooting dynamics of large and small trees, the impact of salt marshes (e.g. species and structure) on mangroves, and the influence of vegetation on soil properties along transects from underneath the mangrove canopy into the surrounding salt marsh. Vegetation and rooting dynamics differed in horizontal reach, and there was a positive relationship between mangrove tree height and rooting extent. We found that the horizontal expansion of mangrove roots into salt marsh extended up to eight meters beyond the aboveground boundary. Variation in vegetation structure and local hydrology appear to control mangrove seedling dynamics. Finally, soil carbon density and organic matter did not differ within locations across the salt marsh-mangrove interface. By studying aboveground and belowground variation across the ecotone, we can better predict the ecological effects of continued range expansion in response to climate change.

  13. Microspatial ecotone dynamics at a shifting range limit: plant–soil variation across salt marsh–mangrove interfaces

    Science.gov (United States)

    Yando, Erik S.; Osland, Michael J.; Hester, Mark H.

    2018-01-01

    Ecotone dynamics and shifting range limits can be used to advance our understanding of the ecological implications of future range expansions in response to climate change. In the northern Gulf of Mexico, the salt marsh–mangrove ecotone is an area where range limits and ecotone dynamics can be studied in tandem as recent decreases in winter temperature extremes have allowed for mangrove expansion at the expense of salt marsh. In this study, we assessed aboveground and belowground plant–soil dynamics across the salt marsh–mangrove ecotone quantifying micro-spatial patterns in horizontal extent. Specifically, we studied vegetation and rooting dynamics of large and small trees, the impact of salt marshes (e.g. species and structure) on mangroves, and the influence of vegetation on soil properties along transects from underneath the mangrove canopy into the surrounding salt marsh. Vegetation and rooting dynamics differed in horizontal reach, and there was a positive relationship between mangrove tree height and rooting extent. We found that the horizontal expansion of mangrove roots into salt marsh extended up to eight meters beyond the aboveground boundary. Variation in vegetation structure and local hydrology appear to control mangrove seedling dynamics. Finally, soil carbon density and organic matter did not differ within locations across the salt marsh-mangrove interface. By studying aboveground and belowground variation across the ecotone, we can better predict the ecological effects of continued range expansion in response to climate change.

  14. High efficiency RF amplifier development over wide dynamic range for accelerator application

    Science.gov (United States)

    Mishra, Jitendra Kumar; Ramarao, B. V.; Pande, Manjiri M.; Joshi, Gopal; Sharma, Archana; Singh, Pitamber

    2017-10-01

    Superconducting (SC) cavities in an accelerating section are designed to have the same geometrical velocity factor (βg). For these cavities, Radio Frequency (RF) power needed to accelerate charged particles varies with the particle velocity factor (β). RF power requirement from one cavity to other can vary by 2-5 dB within the accelerating section depending on the energy gain in the cavity and beam current. In this paper, we have presented an idea to improve operating efficiency of the SC RF accelerators using envelope tracking technique. A study on envelope tracking technique without feedback is carried out on a 1 kW, 325 MHz, class B (conduction angle of 180 degrees) tuned load power amplifier (PA). We have derived expressions for the efficiency and power output for tuned load amplifier operating on the envelope tracking technique. From the derived expressions, it is observed that under constant load resistance to the device (MOSFET), optimum amplifier efficiency is invariant whereas output power varies with the square of drain bias voltage. Experimental results on 1 kW PA module show that its optimum efficiency is always greater than 62% with variation less than 5% from mean value over 7 dB dynamic range. Low power amplifier modules are the basic building block for the high power amplifiers. Therefore, results for 1 kW PA modules remain valid for the high power solid state amplifiers built using these PA modules. The SC RF accelerators using these constant efficiency power amplifiers can improve overall accelerator efficiency.

  15. Local contrast-enhanced MR images via high dynamic range processing.

    Science.gov (United States)

    Chandra, Shekhar S; Engstrom, Craig; Fripp, Jurgen; Neubert, Ales; Jin, Jin; Walker, Duncan; Salvado, Olivier; Ho, Charles; Crozier, Stuart

    2018-09-01

    To develop a local contrast-enhancing and feature-preserving high dynamic range (HDR) image processing algorithm for multichannel and multisequence MR images of multiple body regions and tissues, and to evaluate its performance for structure visualization, bias field (correction) mitigation, and automated tissue segmentation. A multiscale-shape and detail-enhancement HDR-MRI algorithm is applied to data sets of multichannel and multisequence MR images of the brain, knee, breast, and hip. In multisequence 3T hip images, agreement between automatic cartilage segmentations and corresponding synthesized HDR-MRI series were computed for mean voxel overlap established from manual segmentations for a series of cases. Qualitative comparisons between the developed HDR-MRI and standard synthesis methods were performed on multichannel 7T brain and knee data, and multisequence 3T breast and knee data. The synthesized HDR-MRI series provided excellent enhancement of fine-scale structure from multiple scales and contrasts, while substantially reducing bias field effects in 7T brain gradient echo, T 1 and T 2 breast images and 7T knee multichannel images. Evaluation of the HDR-MRI approach on 3T hip multisequence images showed superior outcomes for automatic cartilage segmentations with respect to manual segmentation, particularly around regions with hyperintense synovial fluid, across a set of 3D sequences. The successful combination of multichannel/sequence MR images into a single-fused HDR-MR image format provided consolidated visualization of tissues within 1 omnibus image, enhanced definition of thin, complex anatomical structures in the presence of variable or hyperintense signals, and improved tissue (cartilage) segmentation outcomes. © 2018 International Society for Magnetic Resonance in Medicine.

  16. Co‐occurrence dynamics of endangered Lower Keys marsh rabbits and free‐ranging domestic cats: Prey responses to an exotic predator removal program

    Science.gov (United States)

    Cove, Michael V.; Gardner, Beth; Simons, Theodore R.; O'Connell, Allan F.

    2018-01-01

    The Lower Keys marsh rabbit (Sylvilagus palustris hefneri) is one of many endangered endemic species of the Florida Keys. The main threats are habitat loss and fragmentation from sea‐level rise, development, and habitat succession. Exotic predators such as free‐ranging domestic cats (Felis catus) pose an additional threat to these endangered small mammals. Management strategies have focused on habitat restoration and exotic predator control. However, the effectiveness of predator removal and the effects of anthropogenic habitat modifications and restoration have not been evaluated. Between 2013 and 2015, we used camera traps to survey marsh rabbits and free‐ranging cats at 84 sites in the National Key Deer Refuge, Big Pine Key, Florida, USA. We used dynamic occupancy models to determine factors associated with marsh rabbit occurrence, colonization, extinction, and the co‐occurrence of marsh rabbits and cats during a period of predator removal. Rabbit occurrence was positively related to freshwater habitat and patch size, but was negatively related to the number of individual cats detected at each site. Furthermore, marsh rabbit colonization was negatively associated with relative increases in the number of individual cats at each site between survey years. Cat occurrence was negatively associated with increasing distance from human developments. The probability of cat site extinction was positively related to a 2‐year trapping effort, indicating that predator removal reduced the cat population. Dynamic co‐occurrence models suggested that cats and marsh rabbits co‐occur less frequently than expected under random conditions, whereas co‐detections were site and survey‐specific. Rabbit site extinction and colonization were not strongly conditional on cat presence, but corresponded with a negative association. Our results suggest that while rabbits can colonize and persist at sites where cats occur, it is the number of individual cats at a site that

  17. Co-occurrence dynamics of endangered Lower Keys marsh rabbits and free-ranging domestic cats: Prey responses to an exotic predator removal program.

    Science.gov (United States)

    Cove, Michael V; Gardner, Beth; Simons, Theodore R; O'Connell, Allan F

    2018-04-01

    The Lower Keys marsh rabbit ( Sylvilagus palustris hefneri ) is one of many endangered endemic species of the Florida Keys. The main threats are habitat loss and fragmentation from sea-level rise, development, and habitat succession. Exotic predators such as free-ranging domestic cats ( Felis catus ) pose an additional threat to these endangered small mammals. Management strategies have focused on habitat restoration and exotic predator control. However, the effectiveness of predator removal and the effects of anthropogenic habitat modifications and restoration have not been evaluated. Between 2013 and 2015, we used camera traps to survey marsh rabbits and free-ranging cats at 84 sites in the National Key Deer Refuge, Big Pine Key, Florida, USA. We used dynamic occupancy models to determine factors associated with marsh rabbit occurrence, colonization, extinction, and the co-occurrence of marsh rabbits and cats during a period of predator removal. Rabbit occurrence was positively related to freshwater habitat and patch size, but was negatively related to the number of individual cats detected at each site. Furthermore, marsh rabbit colonization was negatively associated with relative increases in the number of individual cats at each site between survey years. Cat occurrence was negatively associated with increasing distance from human developments. The probability of cat site extinction was positively related to a 2-year trapping effort, indicating that predator removal reduced the cat population. Dynamic co-occurrence models suggested that cats and marsh rabbits co-occur less frequently than expected under random conditions, whereas co-detections were site and survey-specific. Rabbit site extinction and colonization were not strongly conditional on cat presence, but corresponded with a negative association. Our results suggest that while rabbits can colonize and persist at sites where cats occur, it is the number of individual cats at a site that more strongly

  18. Correction of dynamic time-activity curves for gamma-camera dead time, radiotracer delivery, and radioactive decay: special considerations with ultrashort-lived radioisotopes

    International Nuclear Information System (INIS)

    Kuruc, A.; Zimmerman, R.E.; Treves, S.

    1985-01-01

    Time-vs.-activity curves obtained by using ultrashort-lived radioisotopes often need to be corrected for the effects of gamma-camera dead time and physical decay. Count loss due to gamma-camera dead time can be monitored by using an electronic oscillator incorporated into the gamma camera. Two algorithms that use this information to correct time-activity curves are discussed. It is also shown that the effect of physical decay on a time-activity curve is dependent on the time course of delivery of the radioisotope to the organ of interest. A mathematical technique that corrects physical decay is described

  19. Science, conservation, and camera traps

    Science.gov (United States)

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

    2011-01-01

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

  20. Traveling wave deflector design for femtosecond streak camera

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  1. Traveling wave deflector design for femtosecond streak camera

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-21

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

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

    Science.gov (United States)

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

    2001-10-01

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

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

    International Nuclear Information System (INIS)

    Stradling, G.L.

    1981-04-01

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

  4. Dynamic CFD Simulations of the Supersonic Inflatable Aerodynamic Decelerator (SIAD) Ballistic Range Tests

    Science.gov (United States)

    Brock, Joseph M; Stern, Eric

    2016-01-01

    Dynamic CFD simulations of the SIAD ballistic test model were performed using US3D flow solver. Motivation for performing these simulations is for the purpose of validation and verification of the US3D flow solver as a viable computational tool for predicting dynamic coefficients.

  5. [Dynamics of food transit in gastrectomized patients with and without dumping syndrome studied with the gamma camera and a marked meal].

    Science.gov (United States)

    Palermo, F; Boccaletto, F; Allegri, F; Tommaseo, T; Chiara, G

    1988-01-01

    Scintigraphy was performed on a group of patients following the administration of a solid radiolabelled meal. As a tracer, human albumin microspheres were used with 99mTc, mixed with fresh scrambled eggs, eaten as a sandwich in two slices of white bread. The analysis of transit and emptying-rate of the radiolabelled meal in the gastric or derivative loop areas was performed by means of a medium field (300 mm) gamma camera interfaced with a digital computer; the data were collected at 15" frames for 90'-120'. Twenty-nine patients were examined who had undergone sub-total gastrectomy: 11 of them were "dumpers" and 18 "non-dumpers"; moreover, 9 volunteers without any history of gastrointestinal diseases and 11 patients with different gastric disorders were checked. In the first group of gastrectomized patients the half-emptying time (T50) was significantly shorter than in the 11 people being checked (Md = 27.5 +/- 10.8 versus 69.6 +/- 19 minutes); in "non-dumpers" T50 was even shorter (Md = 24.2 +/- 13 min). There was no significant statistical difference between the two classes of gastroresected patients in both T50 and emptying-rate of the radioactive solid food, which excludes the accelerated transit as a factor in the functional post-prandial symptoms of the dumping syndrome. On the contrary, the dynamic selective analysis of the radiolabelled food transit through derivative afferent and efferent loops showed different patterns in the two groups of gastroresected patients: the progression of the propulsive wave was very irregular and constantly hyperperistaltic only in the dumpers.

  6. Comparison of three different concepts of high dynamic range and dependability optimised current measurement digitisers for beam loss systems

    CERN Document Server

    Viganò, W; Effinger, E; Venturini, G G; Zamantzas, C

    2012-01-01

    Three Different Concepts of High Dynamic Range and Dependability Optimised Current Measurement Digitisers for Beam Loss Systems will be compared on this paper. The first concept is based on Current to Frequency Conversion, enhanced with an ADC for extending the dynamic range and decreasing the response time. A summary of 3 years’ worth of operational experience with such a system for LHC beam loss monitoring will be given. The second principle is based on an Adaptive Current to Frequency Converter implemented in an ASIC. The basic parameters of the circuit are discussed and compared with measurements. Several measures are taken to harden both circuits against single event effects and to make them tolerant for operation in radioactive environments. The third circuit is based on a Fully Differential Integrator for enhanced dynamic range, where laboratory and test installation measurements will be presented. All circuits are designed to avoid any dead time in the acquisition and have reliability and fail safe...

  7. Expanding the linear dynamic range for quantitative liquid chromatography-high resolution mass spectrometry utilizing natural isotopologue signals

    International Nuclear Information System (INIS)

    Liu, Hanghui; Lam, Lily; Yan, Lin; Chi, Bert; Dasgupta, Purnendu K.

    2014-01-01

    Highlights: • Less abundant isotopologue ions were utilized to decrease detector saturation. • A 25–50 fold increase in the upper limit of dynamic range was demonstrated. • Linear dynamic range was expanded without compromising mass resolution. - Abstract: The linear dynamic range (LDR) for quantitative liquid chromatography–mass spectrometry can be extended until ionization saturation is reached by using a number of target isotopologue ions in addition to the normally used target ion that provides the highest sensitivity. Less abundant isotopologue ions extend the LDR: the lower ion abundance decreases the probability of ion detector saturation. Effectively the sensitivity decreases and the upper limit of the LDR increases. We show in this paper that the technique is particularly powerful with a high resolution time of flight mass spectrometer because the data for all ions are automatically acquired, and we demonstrated this for four small organic molecules; the upper limits of LDRs increased by 25–50 times

  8. Human tracking over camera networks: a review

    Science.gov (United States)

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

    2017-12-01

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

  9. Photogrammetric Applications of Immersive Video Cameras

    OpenAIRE

    Kwiatek, K.; Tokarczyk, R.

    2014-01-01

    The paper investigates immersive videography and its application in close-range photogrammetry. Immersive video involves the capture of a live-action scene that presents a 360° field of view. It is recorded simultaneously by multiple cameras or microlenses, where the principal point of each camera is offset from the rotating axis of the device. This issue causes problems when stitching together individual frames of video separated from particular cameras, however there are ways to ov...

  10. Performance analysis for gait in camera networks

    OpenAIRE

    Michela Goffredo; Imed Bouchrika; John Carter; Mark Nixon

    2008-01-01

    This paper deploys gait analysis for subject identification in multi-camera surveillance scenarios. We present a new method for viewpoint independent markerless gait analysis that does not require camera calibration and works with a wide range of directions of walking. These properties make the proposed method particularly suitable for gait identification in real surveillance scenarios where people and their behaviour need to be tracked across a set of cameras. Tests on 300 synthetic and real...

  11. High-dynamic range imaging techniques based on both color-separation algorithms used in conventional graphic arts and the human visual perception modeling

    Science.gov (United States)

    Lo, Mei-Chun; Hsieh, Tsung-Hsien; Perng, Ruey-Kuen; Chen, Jiong-Qiao

    2010-01-01

    The aim of this research is to derive illuminant-independent type of HDR imaging modules which can optimally multispectrally reconstruct of every color concerned in high-dynamic-range of original images for preferable cross-media color reproduction applications. Each module, based on either of broadband and multispectral approach, would be incorporated models of perceptual HDR tone-mapping, device characterization. In this study, an xvYCC format of HDR digital camera was used to capture HDR scene images for test. A tone-mapping module was derived based on a multiscale representation of the human visual system and used equations similar to a photoreceptor adaptation equation, proposed by Michaelis-Menten. Additionally, an adaptive bilateral type of gamut mapping algorithm, using approach of a multiple conversing-points (previously derived), was incorporated with or without adaptive Un-sharp Masking (USM) to carry out the optimization of HDR image rendering. An LCD with standard color space of Adobe RGB (D65) was used as a soft-proofing platform to display/represent HDR original RGB images, and also evaluate both renditionquality and prediction-performance of modules derived. Also, another LCD with standard color space of sRGB was used to test gamut-mapping algorithms, used to be integrated with tone-mapping module derived.

  12. Dynamics of Phosphorus export from small forested catchments in low mountain ranges in Germany

    Science.gov (United States)

    Julich, Stefan; Julich, Dorit; Benning, Raphael; Feger, Karl-Heinz

    2017-04-01

    Phosphorus (P) plays an important role in the nutrition of forest ecosystem. The transport of P in forest soils predominantly occurs along preferential water flow pathways bypassing large parts of the soil matrix. Therefore, rapid flow processes by preferential flow and/or during storm events may lead to significant P losses from forest soils. However only little knowledge about the dynamics, magnitude and driving processes of P exports into surface water exist. In this contribution, we present the results of two studies where two small forested catchments have been monitored for a period around 3 years. Both catchments are situated in low mountain ranges in Saxony (catchment size 21 ha) and Thuringia (catchment size 5 ha) representing medium P contents in the topsoil of 1142 mg kg-1 and 834 mg kg-1 respectively. During the regular sampling (monthly to weekly sampling frequency), the mean Total-P concentrations of 23 μg L-1(Thuringian Site) and 8 μg L-1(Saxonian Site) have been measured. However, during single storm events Total-P concentrations increased considerably with maximum concentrations of 134 μg L-1(Thuringian Site) and 203 μg L-1(Saxonian Site). Our findings indicate that during storm events, especially after longer dry periods, significant amounts of phosphorus can be exported from forest ecosystems. Comparison of discharge-concentration patterns of Total-P, Nitrogen and DOC, as well as dye tracer experiments, suggest that preferential flow along biopores and stone surfaces, and the interface between mineral soil and litter layer are main pathways of export from forests. For the site in Saxony we calculated mean annual export rates of 32.8 to 33.5 g ha-1 a-1 based on the weekly sampling with different load calculation methods (flow weighted methods up to linear regression models). If the events are included into the annual load calculation the mean annual export fluxes increase from 47.8 to 58.6 g ha-1 a-1 based on the different load calculation

  13. Flat ended steel wires, backscattering targets for calibrating over a large dynamic range

    NARCIS (Netherlands)

    Lubbers, Jaap; Graaff, Reindert

    2006-01-01

    A series of flat ended stainless steel wires was constructed and experimentally evaluated as point targets giving a calibrated backscattering over a large range (up to 72 dB) for ultrasound frequencies in the range 2 to 10 MHz. Over a range of 36 dB, theory was strictly followed (within 1 dB),

  14. Making Ceramic Cameras

    Science.gov (United States)

    Squibb, Matt

    2009-01-01

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

  15. Competition and facilitation may lead to asymmetric range shift dynamics with climate change.

    Science.gov (United States)

    Ettinger, Ailene; HilleRisLambers, Janneke

    2017-09-01

    Forecasts of widespread range shifts with climate change stem from assumptions that climate drives species' distributions. However, local adaptation and biotic interactions also influence range limits and thus may impact range shifts. Despite the potential importance of these factors, few studies have directly tested their effects on performance at range limits. We address how population-level variation and biotic interactions may affect range shifts by transplanting seeds and seedlings of western North American conifers of different origin populations into different competitive neighborhoods within and beyond their elevational ranges and monitoring their performance. We find evidence that competition with neighboring trees limits performance within current ranges, but that interactions between adults and juveniles switch from competitive to facilitative at upper range limits. Local adaptation had weaker effects on performance that did not predictably vary with range position or seed origin. Our findings suggest that competitive interactions may slow species turnover within forests at lower range limits, whereas facilitative interactions may accelerate the pace of tree expansions upward near timberline. © 2017 John Wiley & Sons Ltd.

  16. Adapting Virtual Camera Behaviour

    DEFF Research Database (Denmark)

    Burelli, Paolo

    2013-01-01

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

  17. Intelligibility and Clarity of Reverberant Speech: Effects of Wide Dynamic Range Compression Release Time and Working Memory

    Science.gov (United States)

    Reinhart, Paul N.; Souza, Pamela E.

    2016-01-01

    Purpose: The purpose of this study was to examine the effects of varying wide dynamic range compression (WDRC) release time on intelligibility and clarity of reverberant speech. The study also considered the role of individual working memory. Method: Thirty older listeners with mild to moderately-severe sloping sensorineural hearing loss…

  18. Enhancement tuning and control for high dynamic range images in multi-scale locally adaptive contrast enhancement algorithms

    NARCIS (Netherlands)

    Cvetkovic, S.D.; Schirris, J.; With, de P.H.N.

    2009-01-01

    For real-time imaging in surveillance applications, visibility of details is of primary importance to ensure customer confidence. If we display High Dynamic-Range (HDR) scenes whose contrast spans four or more orders of magnitude on a conventional monitor without additional processing, results are

  19. Dynamic-range reduction by peak clipping or compression and its effects on phoneme perception in hearing-impaired listeners

    NARCIS (Netherlands)

    Dreschler, W. A.

    1988-01-01

    In this study, differences between dynamic-range reduction by peak clipping and single-channel compression for phoneme perception through conventional hearing aids have been investigated. The results from 16 hearing-impaired listeners show that compression limiting yields significantly better

  20. Synthesis of Algorithm for Range Measurement Equipment to Track Maneuvering Aircraft Using Data on Its Dynamic and Kinematic Parameters

    Science.gov (United States)

    Pudovkin, A. P.; Panasyuk, Yu N.; Danilov, S. N.; Moskvitin, S. P.

    2018-05-01

    The problem of improving automated air traffic control systems is considered through the example of the operation algorithm synthesis for a range measurement channel to track the aircraft, using its kinematic and dynamic parameters. The choice of the state and observation models has been justified, the computer simulations have been performed and the results of the investigated algorithms have been obtained.

  1. Coupled quantum-classical method for long range charge transfer: relevance of the nuclear motion to the quantum electron dynamics

    International Nuclear Information System (INIS)

    Da Silva, Robson; Hoff, Diego A; Rego, Luis G C

    2015-01-01

    Charge and excitonic-energy transfer phenomena are fundamental for energy conversion in solar cells as well as artificial photosynthesis. Currently, much interest is being paid to light-harvesting and energy transduction processes in supramolecular structures, where nuclear dynamics has a major influence on electronic quantum dynamics. For this reason, the simulation of long range electron transfer in supramolecular structures, under environmental conditions described within an atomistic framework, has been a difficult problem to study. This work describes a coupled quantum mechanics/molecular mechanics method that aims at describing long range charge transfer processes in supramolecular systems, taking into account the atomistic details of large molecular structures, the underlying nuclear motion, and environmental effects. The method is applied to investigate the relevance of electron–nuclei interaction on the mechanisms for photo-induced electron–hole pair separation in dye-sensitized interfaces as well as electronic dynamics in molecular structures. (paper)

  2. Streak cameras and their applications

    International Nuclear Information System (INIS)

    Bernet, J.M.; Imhoff, C.

    1987-01-01

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

  3. Digital airborne camera introduction and technology

    CERN Document Server

    Sandau, Rainer

    2014-01-01

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

  4. Short-time dynamics of lysozyme solutions with competing short-range attraction and long-range repulsion: Experiment and theory

    Science.gov (United States)

    Riest, Jonas; Nägele, Gerhard; Liu, Yun; Wagner, Norman J.; Godfrin, P. Douglas

    2018-02-01

    Recently, atypical static features of microstructural ordering in low-salinity lysozyme protein solutions have been extensively explored experimentally and explained theoretically based on a short-range attractive plus long-range repulsive (SALR) interaction potential. However, the protein dynamics and the relationship to the atypical SALR structure remain to be demonstrated. Here, the applicability of semi-analytic theoretical methods predicting diffusion properties and viscosity in isotropic particle suspensions to low-salinity lysozyme protein solutions is tested. Using the interaction potential parameters previously obtained from static structure factor measurements, our results of Monte Carlo simulations representing seven experimental lysoyzme samples indicate that they exist either in dispersed fluid or random percolated states. The self-consistent Zerah-Hansen scheme is used to describe the static structure factor, S(q), which is the input to our calculation schemes for the short-time hydrodynamic function, H(q), and the zero-frequency viscosity η. The schemes account for hydrodynamic interactions included on an approximate level. Theoretical predictions for H(q) as a function of the wavenumber q quantitatively agree with experimental results at small protein concentrations obtained using neutron spin echo measurements. At higher concentrations, qualitative agreement is preserved although the calculated hydrodynamic functions are overestimated. We attribute the differences for higher concentrations and lower temperatures to translational-rotational diffusion coupling induced by the shape and interaction anisotropy of particles and clusters, patchiness of the lysozyme particle surfaces, and the intra-cluster dynamics, features not included in our simple globular particle model. The theoretical results for the solution viscosity, η, are in qualitative agreement with our experimental data even at higher concentrations. We demonstrate that semi

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-15

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

  6. A wide dynamic range BF3 neutron monitor with front-end electronics based on a logarithmic amplifier

    International Nuclear Information System (INIS)

    Ferrarini, M.; Varoli, V.; Favalli, A.; Caresana, M.; Pedersen, B.

    2010-01-01

    This paper describes a wide dynamic range neutron monitor based on a BF 3 neutron detector. The detector is used in current mode, and front-end electronics based on a logarithmic amplifier are used in order to have a measurement capability ranging over many orders of magnitude. The system has been calibrated at the Polytechnic of Milan, CESNEF, with an AmBe neutron source, and has been tested in a pulsed field at the PUNITA facility at JRC, Ispra. The detector has achieved a dynamic range of over 6 orders of magnitude, being able to measure single neutron pulses and showing saturation-free response for a reaction rate up to 10 6 s -1 . It has also proved effective in measuring the PUNITA facility pulse integral fluence.

  7. A wide dynamic range BF{sub 3} neutron monitor with front-end electronics based on a logarithmic amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Ferrarini, M., E-mail: michele.ferrarini@polimi.i [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Fondazione CNAO, via Caminadella 16, 20123 Milano (Italy); Varoli, V. [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Favalli, A. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP 800, Via E. Fermi, 21027 Ispra (Vatican City State, Holy See) (Italy); Caresana, M. [Politecnico di Milano, Dipartimento Energia, via G. Ponzio 34/3, I-20133 Milano (Italy); Pedersen, B. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP 800, Via E. Fermi, 21027 Ispra (Italy)

    2010-02-01

    This paper describes a wide dynamic range neutron monitor based on a BF{sub 3} neutron detector. The detector is used in current mode, and front-end electronics based on a logarithmic amplifier are used in order to have a measurement capability ranging over many orders of magnitude. The system has been calibrated at the Polytechnic of Milan, CESNEF, with an AmBe neutron source, and has been tested in a pulsed field at the PUNITA facility at JRC, Ispra. The detector has achieved a dynamic range of over 6 orders of magnitude, being able to measure single neutron pulses and showing saturation-free response for a reaction rate up to 10{sup 6} s{sup -1}. It has also proved effective in measuring the PUNITA facility pulse integral fluence.

  8. A Dynamic Multi-Level Factor Model with Long-Range Dependence

    DEFF Research Database (Denmark)

    Ergemen, Yunus Emre; Rodríguez-Caballero, Carlos Vladimir

    A dynamic multi-level factor model with stationary or nonstationary global and regional factors is proposed. In the model, persistence in global and regional common factors as well as innovations allows for the study of fractional cointegrating relationships. Estimation of global and regional...

  9. Intramolecular three-colour single pair FRET of intrinsically disordered proteins with increased dynamic range.

    Science.gov (United States)

    Milles, Sigrid; Koehler, Christine; Gambin, Yann; Deniz, Ashok A; Lemke, Edward A

    2012-10-01

    Single molecule observation of fluorescence resonance energy transfer can be used to provide insight into the structure and dynamics of proteins. Using a straightforward triple-colour labelling strategy, we present a measurement and analysis scheme that can simultaneously study multiple regions within single intrinsically disordered proteins.

  10. Evaluation of dynamically dimensioned search algorithm for optimizing SWAT by altering sampling distributions and searching range

    Science.gov (United States)

    The primary advantage of Dynamically Dimensioned Search algorithm (DDS) is that it outperforms many other optimization techniques in both convergence speed and the ability in searching for parameter sets that satisfy statistical guidelines while requiring only one algorithm parameter (perturbation f...

  11. Experimental comparison of the high-speed imaging performance of an EM-CCD and sCMOS camera in a dynamic live-cell imaging test case.

    Directory of Open Access Journals (Sweden)

    Hope T Beier

    Full Text Available The study of living cells may require advanced imaging techniques to track weak and rapidly changing signals. Fundamental to this need is the recent advancement in camera technology. Two camera types, specifically sCMOS and EM-CCD, promise both high signal-to-noise and high speed (>100 fps, leaving researchers with a critical decision when determining the best technology for their application. In this article, we compare two cameras using a live-cell imaging test case in which small changes in cellular fluorescence must be rapidly detected with high spatial resolution. The EM-CCD maintained an advantage of being able to acquire discernible images with a lower number of photons due to its EM-enhancement. However, if high-resolution images at speeds approaching or exceeding 1000 fps are desired, the flexibility of the full-frame imaging capabilities of sCMOS is superior.

  12. Integrating Gigabit ethernet cameras into EPICS at Diamond light source

    International Nuclear Information System (INIS)

    Cobb, T.

    2012-01-01

    At Diamond Light Source a range of cameras are used to provide images for diagnostic purposes in both the accelerator and photo beamlines. The accelerator and existing beamlines use Point Grey Flea and Flea2 Firewire cameras. We have selected Gigabit Ethernet cameras supporting GigE Vision for our new photon beamlines. GigE Vision is an interface standard for high speed Ethernet cameras which encourages inter-operability between manufacturers. This paper describes the challenges encountered while integrating GigE Vision cameras from a range of vendors into EPICS. GigE Vision cameras appear to be more reliable than the Firewire cameras, and the simple cabling makes much easier to move the cameras to different positions. Upcoming power over Ethernet versions of the cameras will reduce the number of cables still further

  13. Development and characterization of a CCD camera system for use on six-inch manipulator systems

    International Nuclear Information System (INIS)

    Logory, L.M.; Bell, P.M.; Conder, A.D.; Lee, F.D.

    1996-01-01

    The Lawrence Livermore National Laboratory has designed, constructed, and fielded a compact CCD camera system for use on the Six Inch Manipulator (SIM) at the Nova laser facility. The camera system has been designed to directly replace the 35 mm film packages on all active SIM-based diagnostics. The unit's electronic package is constructed for small size and high thermal conductivity using proprietary printed circuit board technology, thus reducing the size of the overall camera and improving its performance when operated within the vacuum environment of the Nova laser target chamber. The camera has been calibrated and found to yield a linear response, with superior dynamic range and signal-to-noise levels as compared to T-Max 3200 optic film, while providing real-time access to the data. Limiting factors related to fielding such devices on Nova will be discussed, in addition to planned improvements of the current design

  14. Combining local and global optimisation for virtual camera control

    OpenAIRE

    Burelli, Paolo; Yannakakis, Georgios N.; 2010 IEEE Symposium on Computational Intelligence and Games

    2010-01-01

    Controlling a virtual camera in 3D computer games is a complex task. The camera is required to react to dynamically changing environments and produce high quality visual results and smooth animations. This paper proposes an approach that combines local and global search to solve the virtual camera control problem. The automatic camera control problem is described and it is decomposed into sub-problems; then a hierarchical architecture that solves each sub-problem using the most appropriate op...

  15. Infrared Camera Diagnostic for Heat Flux Measurements on NSTX

    International Nuclear Information System (INIS)

    D. Mastrovito; R. Maingi; H.W. Kugel; A.L. Roquemore

    2003-01-01

    An infrared imaging system has been installed on NSTX (National Spherical Torus Experiment) at the Princeton Plasma Physics Laboratory to measure the surface temperatures on the lower divertor and center stack. The imaging system is based on an Indigo Alpha 160 x 128 microbolometer camera with 12 bits/pixel operating in the 7-13 (micro)m range with a 30 Hz frame rate and a dynamic temperature range of 0-700 degrees C. From these data and knowledge of graphite thermal properties, the heat flux is derived with a classic one-dimensional conduction model. Preliminary results of heat flux scaling are reported

  16. A design of an on-orbit radiometric calibration device for high dynamic range infrared remote sensors

    Science.gov (United States)

    Sheng, Yicheng; Jin, Weiqi; Dun, Xiong; Zhou, Feng; Xiao, Si

    2017-10-01

    With the demand of quantitative remote sensing technology growing, high reliability as well as high accuracy radiometric calibration technology, especially the on-orbit radiometric calibration device has become an essential orientation in term of quantitative remote sensing technology. In recent years, global launches of remote sensing satellites are equipped with innovative on-orbit radiometric calibration devices. In order to meet the requirements of covering a very wide dynamic range and no-shielding radiometric calibration system, we designed a projection-type radiometric calibration device for high dynamic range sensors based on the Schmidt telescope system. In this internal radiometric calibration device, we select the EF-8530 light source as the calibration blackbody. EF-8530 is a high emittance Nichrome (Ni-Cr) reference source. It can operate in steady or pulsed state mode at a peak temperature of 973K. The irradiance from the source was projected to the IRFPA. The irradiance needs to ensure that the IRFPA can obtain different amplitude of the uniform irradiance through the narrow IR passbands and cover the very wide dynamic range. Combining the internal on-orbit radiometric calibration device with the specially designed adaptive radiometric calibration algorithms, an on-orbit dynamic non-uniformity correction can be accomplished without blocking the optical beam from outside the telescope. The design optimizes optics, source design, and power supply electronics for irradiance accuracy and uniformity. The internal on-orbit radiometric calibration device not only satisfies a series of indexes such as stability, accuracy, large dynamic range and uniformity of irradiance, but also has the advantages of short heating and cooling time, small volume, lightweight, low power consumption and many other features. It can realize the fast and efficient relative radiometric calibration without shielding the field of view. The device can applied to the design and

  17. The dynamical mechanical properties of tungsten under compression at working temperature range of divertors

    Science.gov (United States)

    Zhu, C. C.; Song, Y. T.; Peng, X. B.; Wei, Y. P.; Mao, X.; Li, W. X.; Qian, X. Y.

    2016-02-01

    In the divertor structure of ITER and EAST with mono-block module, tungsten plays not only a role of armor material but also a role of structural material, because electromagnetic (EM) impact will be exerted on tungsten components in VDEs or CQ. The EM loads can reach to 100 MN, which would cause high strain rates. In addition, directly exposed to high-temperature plasma, the temperature regime of divertor components is complex. Aiming at studying dynamical response of tungsten divertors under EM loads, an experiment on tungsten employed in EAST divertors was performed using a Kolsky bar system. The testing strain rates and temperatures is derived from actual working conditions, which makes the constitutive equation concluded by using John-Cook model and testing data very accurate and practical. The work would give a guidance to estimate the dynamical response, fatigue life and damage evolution of tungsten divertor components under EM impact loads.

  18. SiGe HBT linear-in-dB high dynamic range RF envelope detectors and wideband high linearity amplifiers

    OpenAIRE

    Pan, Hsuan-yu

    2010-01-01

    This research work aims on exploiting SiGe HBT technologies in high dynamic range wideband RF linear-in- dB envelope detectors and linear amplifiers. First, an improved all-npn broadband highly linear SiGe HBT differential amplifier is presented based on a variation of Caprio's Quad. A broadband linear amplifier with 46dBm OIP₃ at 20MHz, 34dBm OIP₃ at 1GHz, 6dB noise figure and 10.3dBm P₁dB is demonstrated. Second, an improved exact dynamic model of a fast-settling linear-in-dB Automatic Gain...

  19. Interspecific geographic range size-body size relationship and the diversification dynamics of Neotropical furnariid birds.

    Science.gov (United States)

    Inostroza-Michael, Oscar; Hernández, Cristián E; Rodríguez-Serrano, Enrique; Avaria-Llautureo, Jorge; Rivadeneira, Marcelo M

    2018-05-01

    Among the earliest macroecological patterns documented, is the range and body size relationship, characterized by a minimum geographic range size imposed by the species' body size. This boundary for the geographic range size increases linearly with body size and has been proposed to have implications in lineages evolution and conservation. Nevertheless, the macroevolutionary processes involved in the origin of this boundary and its consequences on lineage diversification have been poorly explored. We evaluate the macroevolutionary consequences of the difference (hereafter the distance) between the observed and the minimum range sizes required by the species' body size, to untangle its role on the diversification of a Neotropical species-rich bird clade using trait-dependent diversification models. We show that speciation rate is a positive hump-shaped function of the distance to the lower boundary. The species with highest and lowest distances to minimum range size had lower speciation rates, while species close to medium distances values had the highest speciation rates. Further, our results suggest that the distance to the minimum range size is a macroevolutionary constraint that affects the diversification process responsible for the origin of this macroecological pattern in a more complex way than previously envisioned. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

  20. Dynamic Confinement of ITER Plasma by O-Mode Driver at Electron Cyclotron Frequency Range

    Science.gov (United States)

    Stefan, V. Alexander

    2009-05-01

    A low B-field side launched electron cyclotron O-Mode driver leads to the dynamic rf confinement, in addition to rf turbulent heating, of ITER plasma. The scaling law for the local energy confinement time τE is evaluated (τE ˜ 3neTe/2Q, where (3/2) neTe is the local plasma thermal energy density and Q is the local rf turbulent heating rate). The dynamics of unstable dissipative trapped particle modes (DTPM) strongly coupled to Trivelpiece-Gould (T-G) modes is studied for gyrotron frequency 170GHz; power˜24 MW CW; and on-axis B-field ˜ 10T. In the case of dynamic stabilization of DTPM turbulence and for the heavily damped T-G modes, the energy confinement time scales as τE˜(I0)-2, whereby I0(W/m^2) is the O-Mode driver irradiance. R. Prater et. al., Nucl. Fusion 48, No 3 (March 2008). E. P. Velikhov, History of the Russian Tokamak and the Tokamak Thermonuclear Fusion Research Worldwide That Led to ITER (Documentary movie; Stefan Studios Int'l, La Jolla, CA, 2008; E. P. Velikhov, V. Stefan.) M N Rosenbluth, Phys. Scr. T2A 104-109 1982 B. B. Kadomtsev and O. P. Pogutse, Nucl. Fusion 11, 67 (1971).

  1. High-performance dual-speed CCD camera system for scientific imaging

    Science.gov (United States)

    Simpson, Raymond W.

    1996-03-01

    Traditionally, scientific camera systems were partitioned with a `camera head' containing the CCD and its support circuitry and a camera controller, which provided analog to digital conversion, timing, control, computer interfacing, and power. A new, unitized high performance scientific CCD camera with dual speed readout at 1 X 106 or 5 X 106 pixels per second, 12 bit digital gray scale, high performance thermoelectric cooling, and built in composite video output is described. This camera provides all digital, analog, and cooling functions in a single compact unit. The new system incorporates the A/C converter, timing, control and computer interfacing in the camera, with the power supply remaining a separate remote unit. A 100 Mbyte/second serial link transfers data over copper or fiber media to a variety of host computers, including Sun, SGI, SCSI, PCI, EISA, and Apple Macintosh. Having all the digital and analog functions in the camera made it possible to modify this system for the Woods Hole Oceanographic Institution for use on a remote controlled submersible vehicle. The oceanographic version achieves 16 bit dynamic range at 1.5 X 105 pixels/second, can be operated at depths of 3 kilometers, and transfers data to the surface via a real time fiber optic link.

  2. Improved approach to characterizing and presenting streak camera performance

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  3. Photometric Calibration of Consumer Video Cameras

    Science.gov (United States)

    Suggs, Robert; Swift, Wesley, Jr.

    2007-01-01

    Equipment and techniques have been developed to implement a method of photometric calibration of consumer video cameras for imaging of objects that are sufficiently narrow or sufficiently distant to be optically equivalent to point or line sources. Heretofore, it has been difficult to calibrate consumer video cameras, especially in cases of image saturation, because they exhibit nonlinear responses with dynamic ranges much smaller than those of scientific-grade video cameras. The present method not only takes this difficulty in stride but also makes it possible to extend effective dynamic ranges to several powers of ten beyond saturation levels. The method will likely be primarily useful in astronomical photometry. There are also potential commercial applications in medical and industrial imaging of point or line sources in the presence of saturation.This development was prompted by the need to measure brightnesses of debris in amateur video images of the breakup of the Space Shuttle Columbia. The purpose of these measurements is to use the brightness values to estimate relative masses of debris objects. In most of the images, the brightness of the main body of Columbia was found to exceed the dynamic ranges of the cameras. A similar problem arose a few years ago in the analysis of video images of Leonid meteors. The present method is a refined version of the calibration method developed to solve the Leonid calibration problem. In this method, one performs an endto- end calibration of the entire imaging system, including not only the imaging optics and imaging photodetector array but also analog tape recording and playback equipment (if used) and any frame grabber or other analog-to-digital converter (if used). To automatically incorporate the effects of nonlinearity and any other distortions into the calibration, the calibration images are processed in precisely the same manner as are the images of meteors, space-shuttle debris, or other objects that one seeks to

  4. Home range dynamics of mountain hare (Lepus timidus in the Swiss Alps

    Directory of Open Access Journals (Sweden)

    Anne-Sophie Genini-Gamboni

    2009-02-01

    Full Text Available Abstract Little is known on the ecology and behaviour of alpine mountain hare (Lepus timidus. Between 1996 and 1997 we analysed by radiotracking the pattern of space use of 8 mountain hares from the Swiss Alps. We estimated home range size using both the kernel density estimator and the minimum convex polygon. We found smaller ranges (38 ha compared to those reported for the species in boreal or arctic habitats, but similar to ranges in Scotland. Hares did not use a centre of major activity (core area and showed high home range overlap, confirming their non-territorial behaviour. Smaller ranges were used during winter compared to the other seasons, whilst no difference in size was found between sexes. Riassunto Dinamica dell'uso dello spazio della lepre bianca (Lepus timidus nelle Alpi Svizzere Le informazioni relative all'ecologia e al comportamento della lepre alpina (Lepus timidus sono ad oggi scarse. In questo studio abbiamo analizzato l'utilizzo dello spazio di una popolazione di lepre bianca sulle Alpi Svizzere. Tra il 1996 e il 1997 sono stati marcati con redio collare 8 individui di lepre alpina. L'home range è stato calcolato utilizzando lo stimatore di densità kernel (KDE ed il metodo del minimo poligono convesso (MCP. L'ampiezza degli home range (38 ha è risultata inferiore a quella riportata per la specie in habitat boreali ed artici. ma simile a quella riscontrata in Scozia. All'interno dell home range non è stato rilevato alcun centro di maggiore attività (core area ed è stata evidenziata una notevole sovrapposizione tra gli stessi, confermando la non territorialità della specie. Le aree frequentate in inverno sono risultate più piccole rispetto alle altre stagioni e non sono state riscontrate differenze tra i sessi.

  5. Light detection and ranging measurements of wake dynamics. Part II: two-dimensional scanning

    DEFF Research Database (Denmark)

    Trujillo, Juan-José; Bingöl, Ferhat; Larsen, Gunner Chr.

    2011-01-01

    the instantaneous transversal wake position which is quantitatively compared with the prediction of the Dynamic Wake Meandering model. The results, shown for two 10-min time series, suggest that the conjecture of the wake behaving as a passive tracer is a fair approximation; this corroborates and expands...... the results of one-dimensional measurements already presented in the first part of this paper. Consequently, it is now possible to separate the deterministic and turbulent parts of the wake wind field, thus enabling capturing the wake in the meandering frame of reference. The results correspond, qualitatively...

  6. Combining short- and long-range fluorescence reporters with simulations to explore the intramolecular dynamics of an intrinsically disordered protein

    Science.gov (United States)

    Zosel, Franziska; Haenni, Dominik; Soranno, Andrea; Nettels, Daniel; Schuler, Benjamin

    2017-10-01

    Intrinsically disordered proteins (IDPs) are increasingly recognized as a class of molecules that can exert essential biological functions even in the absence of a well-defined three-dimensional structure. Understanding the conformational distributions and dynamics of these highly flexible proteins is thus essential for explaining the molecular mechanisms underlying their function. Single-molecule fluorescence spectroscopy in combination with Förster resonance energy transfer (FRET) is a powerful tool for probing intramolecular distances and the rapid long-range distance dynamics in IDPs. To complement the information from FRET, we combine it with photoinduced electron transfer (PET) quenching to monitor local loop-closure kinetics at the same time and in the same molecule. Here we employed this combination to investigate the intrinsically disordered N-terminal domain of HIV-1 integrase. The results show that both long-range dynamics and loop closure kinetics on the sub-microsecond time scale can be obtained reliably from a single set of measurements by the analysis with a comprehensive model of the underlying photon statistics including both FRET and PET. A more detailed molecular interpretation of the results is enabled by direct comparison with a recent extensive atomistic molecular dynamics simulation of integrase. The simulations are in good agreement with experiment and can explain the deviation from simple models of chain dynamics by the formation of persistent local secondary structure. The results illustrate the power of a close combination of single-molecule spectroscopy and simulations for advancing our understanding of the dynamics and detailed mechanisms in unfolded and intrinsically disordered proteins.

  7. Range and variation in landscape patch dynamics: Implications for ecosystem management

    Science.gov (United States)

    Robert E. Keane; Janice L. Garner; Casey Teske; Cathy Stewart; Paul Hessburg

    2001-01-01

    Northern Rocky Mountain landscape patterns are shaped primarily by fire and succession, and conversely, these vegetation patterns influence burning patterns and plant colonization processes. Historical range and variability (HRV) of landscape pattern can be quantified from three sources: (1) historical chronosequences, (2) spatial series, and (3) simulated...

  8. Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering

    KAUST Repository

    Ouda, Mahmoud H.; Khalil, Waleed; Salama, Khaled N.

    2016-01-01

    A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18μm

  9. Atmospheric dynamics and habitability range in Earth-like aquaplanets obliquity simulations

    Science.gov (United States)

    Nowajewski, Priscilla; Rojas, M.; Rojo, P.; Kimeswenger, S.

    2018-05-01

    We present the evolution of the atmospheric variables that affect planetary climate by increasing the obliquity by using a general circulation model (PlaSim) coupled to a slab ocean with mixed layer flux correction. We increase the obliquity between 30° and 90° in 16 aquaplanets with liquid sea surface and perform the simulation allowing the sea ice cover formation to be a consequence of its atmospheric dynamics. Insolation is maintained constant in each experiment, but changing the obliquity affects the radiation budget and the large scale circulation. Earth-like atmospheric dynamics is observed for planets with obliquity under 54°. Above this value, the latitudinal temperature gradient is reversed giving place to a new regime of jet streams, affecting the shape of Hadley and Ferrel cells and changing the position of the InterTropical Convergence Zone. As humidity and high temperatures determine Earth's habitability, we introduce the wet bulb temperature as an atmospheric index of habitability for Earth-like aquaplanets with above freezing temperatures. The aquaplanets are habitable all year round at all latitudes for values under 54°; above this value habitability decreases toward the poles due to high temperatures.

  10. Long-Range Correlations and Memory in the Dynamics of Internet Interdomain Routing.

    Directory of Open Access Journals (Sweden)

    Maksim Kitsak

    Full Text Available Data transfer is one of the main functions of the Internet. The Internet consists of a large number of interconnected subnetworks or domains, known as Autonomous Systems (ASes. Due to privacy and other reasons the information about what route to use to reach devices within other ASes is not readily available to any given AS. The Border Gateway Protocol (BGP is responsible for discovering and distributing this reachability information to all ASes. Since the topology of the Internet is highly dynamic, all ASes constantly exchange and update this reachability information in small chunks, known as routing control packets or BGP updates. In the view of the quick growth of the Internet there are significant concerns with the scalability of the BGP updates and the efficiency of the BGP routing in general. Motivated by these issues we conduct a systematic time series analysis of BGP update rates. We find that BGP update time series are extremely volatile, exhibit long-term correlations and memory effects, similar to seismic time series, or temperature and stock market price fluctuations. The presented statistical characterization of BGP update dynamics could serve as a basis for validation of existing and developing better models of Internet interdomain routing.

  11. Sub-Camera Calibration of a Penta-Camera

    Science.gov (United States)

    Jacobsen, K.; Gerke, M.

    2016-03-01

    cameras of both blocks have the same trend, but as usual for block adjustments with self calibration, they still show significant differences. Based on the very high number of image points the remaining image residuals can be safely determined by overlaying and averaging the image residuals corresponding to their image coordinates. The size of the systematic image errors, not covered by the used additional parameters, is in the range of a square mean of 0.1 pixels corresponding to 0.6μm. They are not the same for both blocks, but show some similarities for corresponding cameras. In general the bundle block adjustment with a satisfying set of additional parameters, checked by remaining systematic errors, is required for use of the whole geometric potential of the penta camera. Especially for object points on facades, often only in two images and taken with a limited base length, the correct handling of systematic image errors is important. At least in the analyzed data sets the self calibration of sub-cameras by bundle block adjustment suffers from the correlation of the inner to the exterior calibration due to missing crossing flight directions. As usual, the systematic image errors differ from block to block even without the influence of the correlation to the exterior orientation.

  12. A > 4 MGy radiation tolerant 8 THzOhm transimpedance amplifier with 50 dB dynamic range

    International Nuclear Information System (INIS)

    Verbeeck, J; Steyaert, M; Leroux, P

    2013-01-01

    A 130 nm Transimpedance Amplifier has been developed with a 255 MHz bandwidth, 90 dBΩ transimpedance gain and a dynamic input range of 1:325 or 50 dB for a photo-diode capacitance of 0.75 pF. The equivalent integrated input noise is 160 nA - 25°C. The gain of the voltage amplifier, used in the transimpedance amplifier (TIA), degrades less than 3% over a temperature range from -40 °C up to 125 °C. The TIA and attenuator exhibit a radiation tolerance larger than 4 MGy, as evidenced by radiation assessment.

  13. EDICAM (Event Detection Intelligent Camera)

    Energy Technology Data Exchange (ETDEWEB)

    Zoletnik, S. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Szabolics, T., E-mail: szabolics.tamas@wigner.mta.hu [Wigner RCP RMI, EURATOM Association, Budapest (Hungary); Kocsis, G.; Szepesi, T.; Dunai, D. [Wigner RCP RMI, EURATOM Association, Budapest (Hungary)

    2013-10-15

    Highlights: ► We present EDICAM's hardware modules. ► We present EDICAM's main design concepts. ► This paper will describe EDICAM firmware architecture. ► Operation principles description. ► Further developments. -- Abstract: A new type of fast framing camera has been developed for fusion applications by the Wigner Research Centre for Physics during the last few years. A new concept was designed for intelligent event driven imaging which is capable of focusing image readout to Regions of Interests (ROIs) where and when predefined events occur. At present these events mean intensity changes and external triggers but in the future more sophisticated methods might also be defined. The camera provides 444 Hz frame rate at full resolution of 1280 × 1024 pixels, but monitoring of smaller ROIs can be done in the 1–116 kHz range even during exposure of the full image. Keeping space limitations and the harsh environment in mind the camera is divided into a small Sensor Module and a processing card interconnected by a fast 10 Gbit optical link. This camera hardware has been used for passive monitoring of the plasma in different devices for example at ASDEX Upgrade and COMPASS with the first version of its firmware. The new firmware and software package is now available and ready for testing the new event processing features. This paper will present the operation principle and features of the Event Detection Intelligent Camera (EDICAM). The device is intended to be the central element in the 10-camera monitoring system of the Wendelstein 7-X stellarator.

  14. Particle identification in a wide dynamic range based on pulse-shape analysis with solid-state detectors

    International Nuclear Information System (INIS)

    Pausch, G.; Hilscher, D.; Ortlepp, H.G.

    1994-04-01

    Heavy ions detected in a planar silicon detector were identified by exploiting a recently proposed combination of the pulse-shape and the time-of-flight techniques. We were able to resolve charge numbers up to Z = 16 within a wide dynamic range of ∼ 1:5, and to identify even isotopes for the elements up to Magnesium. The simple scheme of signal processing is based on conventional electronics and cheap enough to be exploited in large multidetector arrays. (orig.)

  15. Radiation camera exposure control

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  16. GRACE star camera noise

    Science.gov (United States)

    Harvey, Nate

    2016-08-01

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

  17. A Dynamic Range Enhanced Readout Technique with a Two-Step TDC for High Speed Linear CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Zhiyuan Gao

    2015-11-01

    Full Text Available This paper presents a dynamic range (DR enhanced readout technique with a two-step time-to-digital converter (TDC for high speed linear CMOS image sensors. A multi-capacitor and self-regulated capacitive trans-impedance amplifier (CTIA structure is employed to extend the dynamic range. The gain of the CTIA is auto adjusted by switching different capacitors to the integration node asynchronously according to the output voltage. A column-parallel ADC based on a two-step TDC is utilized to improve the conversion rate. The conversion is divided into coarse phase and fine phase. An error calibration scheme is also proposed to correct quantization errors caused by propagation delay skew within −Tclk~+Tclk. A linear CMOS image sensor pixel array is designed in the 0.13 μm CMOS process to verify this DR-enhanced high speed readout technique. The post simulation results indicate that the dynamic range of readout circuit is 99.02 dB and the ADC achieves 60.22 dB SNDR and 9.71 bit ENOB at a conversion rate of 2 MS/s after calibration, with 14.04 dB and 2.4 bit improvement, compared with SNDR and ENOB of that without calibration.

  18. A wideband large dynamic range and high linearity RF front-end for U-band mobile DTV

    International Nuclear Information System (INIS)

    Liu Rongjiang; Liu Shengyou; Guo Guiliang; Cheng Xu; Yan Yuepeng

    2013-01-01

    A wideband large dynamic range and high linearity U-band RF front-end for mobile DTV is introduced, and includes a noise-cancelling low-noise amplifier (LNA), an RF programmable gain amplifier (RFPGA) and a current communicating passive mixer. The noise/distortion cancelling structure and RC post-distortion compensation are employed to improve the linearity of the LNA. An RFPGA with five stages provides large dynamic range and fine gain resolution. A simple resistor voltage network in the passive mixer decreases the gate bias voltage of the mixing transistor, and optimum linearity and symmetrical mixing is obtained at the same time. The RF front-end is implemented in a 0.25 μm CMOS process. Tests show that it achieves an IIP3 (third-order intercept point) of −17 dBm, a conversion gain of 39 dB, and a noise figure of 5.8 dB. The RFPGA achieves a dynamic range of −36.2 to 23.5 dB with a resolution of 0.32 dB. (semiconductor integrated circuits)

  19. Mediator facilitates transcriptional activation and dynamic long-range contacts at the IgH locus during class switch recombination.

    Science.gov (United States)

    Thomas-Claudepierre, Anne-Sophie; Robert, Isabelle; Rocha, Pedro P; Raviram, Ramya; Schiavo, Ebe; Heyer, Vincent; Bonneau, Richard; Luo, Vincent M; Reddy, Janardan K; Borggrefe, Tilman; Skok, Jane A; Reina-San-Martin, Bernardo

    2016-03-07

    Immunoglobulin (Ig) class switch recombination (CSR) is initiated by the transcription-coupled recruitment of activation-induced cytidine deaminase (AID) to Ig switch regions (S regions). During CSR, the IgH locus undergoes dynamic three-dimensional structural changes in which promoters, enhancers, and S regions are brought to close proximity. Nevertheless, little is known about the underlying mechanisms. In this study, we show that Med1 and Med12, two subunits of the mediator complex implicated in transcription initiation and long-range enhancer/promoter loop formation, are dynamically recruited to the IgH locus enhancers and the acceptor regions during CSR and that their knockdown in CH12 cells results in impaired CSR. Furthermore, we show that conditional inactivation of Med1 in B cells results in defective CSR and reduced acceptor S region transcription. Finally, we show that in B cells undergoing CSR, the dynamic long-range contacts between the IgH enhancers and the acceptor regions correlate with Med1 and Med12 binding and that they happen at a reduced frequency in Med1-deficient B cells. Our results implicate the mediator complex in the mechanism of CSR and are consistent with a model in which mediator facilitates the long-range contacts between S regions and the IgH locus enhancers during CSR and their transcriptional activation. © 2016 Thomas-Claudepierre et al.

  20. Solid state video cameras

    CERN Document Server

    Cristol, Y

    2013-01-01

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

  1. Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering

    KAUST Repository

    Ouda, Mahmoud H.

    2016-08-29

    A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18μm CMOS technology. The proposed rectifier architecture is compared to the conventional cross-coupled rectifier. It demonstrates an improvement of more than 40% in the rectifier power conversion efficiency (PCE) and an input power range extension of more than 50% relative to the conventional crosscoupled rectifier. A sensitivity of -15.2dBm (30μW) input power for 1V output voltage and a peak power-conversion efficiency of 65% are achieved for a 50kω load. © 2004-2012 IEEE.

  2. Attractive short-range interatomic potential in the lattice dynamics of niobium and tantalum

    International Nuclear Information System (INIS)

    Onwuagba, B.N.; Pal, S.

    1987-01-01

    It is shown in the framework of the pseudopotential approach that there is a sizable attractive short-range component of the interatomic potential due to the s-d interaction which has the same functional form in real space as the Born-Mayer repulsion due to the overlap of core electron wave functions centred on neighbouring ions. The magnitude of this attractive component is such as to completely cancel the conventional Born-Mayer repulsion, making the resultant short-range interatomic potential attractive rather than repulsive. Numerical calculations show that the attractive interatomics potential, which represents the local-field correction, leads to a better understanding of the occurrence of the soft modes in the phonon dispersion curves of niobium and tantalum

  3. Process simulation in digital camera system

    Science.gov (United States)

    Toadere, Florin

    2012-06-01

    The goal of this paper is to simulate the functionality of a digital camera system. The simulations cover the conversion from light to numerical signal and the color processing and rendering. We consider the image acquisition system to be linear shift invariant and axial. The light propagation is orthogonal to the system. We use a spectral image processing algorithm in order to simulate the radiometric properties of a digital camera. In the algorithm we take into consideration the transmittances of the: light source, lenses, filters and the quantum efficiency of a CMOS (complementary metal oxide semiconductor) sensor. The optical part is characterized by a multiple convolution between the different points spread functions of the optical components. We use a Cooke triplet, the aperture, the light fall off and the optical part of the CMOS sensor. The electrical part consists of the: Bayer sampling, interpolation, signal to noise ratio, dynamic range, analog to digital conversion and JPG compression. We reconstruct the noisy blurred image by blending different light exposed images in order to reduce the photon shot noise, also we filter the fixed pattern noise and we sharpen the image. Then we have the color processing blocks: white balancing, color correction, gamma correction, and conversion from XYZ color space to RGB color space. For the reproduction of color we use an OLED (organic light emitting diode) monitor. The analysis can be useful to assist students and engineers in image quality evaluation and imaging system design. Many other configurations of blocks can be used in our analysis.

  4. Dynamic optimization of the complex adaptive controlling by the structure of enterprise’s product range

    Directory of Open Access Journals (Sweden)

    Andrey Fyodorovich Shorikov

    2013-06-01

    Full Text Available This paper reviews a methodical approach to solve multi-step dynamic problem of optimal integrated adaptive management of a product portfolio structure of the enterprise. For the organization of optimal adaptive terminal control of the system the recurrent algorithm, which reduces an initial multistage problem to the realization of the final sequence of problems of optimal program terminal control is offered. In turn, the decision of each problem of optimal program terminal control is reduced to the realization of the final sequence only single-step operations in the form of the problems solving of linear and convex mathematical programming. Thus, the offered approach allows to develop management solutions at current information support, which consider feedback, and which create the optimal structure of an enterprise’s product lines, contributing to optimising of profits, as well as maintenance of the desired level of profit for a long period of time

  5. Short-range dynamics and prediction of mesoscale flow patterns in the MISTRAL field experiment

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.O.; Kaufmann, P.; Talkner, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    In a limited area of about 50 km by 50 km with complex topography, wind measurements on a dense network were performed during the MISTRAL field experiment in 1991-1992. From these data the characteristic wind fields were identified by an automated classification method. The dynamics of the resulting twelve typical regional flow patterns is studied. It is discussed how transitions between the flow patterns take place and how well the transition probabilities can be described in the framework of a Markov model. Guided by this discussion, a variety of prediction models were tested which allow a short-term forecast of the flow pattern type. It is found that a prediction model which uses forecast information from the synoptic scale has the best forecast skill. (author) 2 figs., 7 refs.

  6. A Benchmark for Virtual Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Yannakakis, Georgios N.

    2015-01-01

    Automatically animating and placing the virtual camera in a dynamic environment is a challenging task. The camera is expected to maximise and maintain a set of properties — i.e. visual composition — while smoothly moving through the environment and avoiding obstacles. A large number of different....... For this reason, in this paper, we propose a benchmark for the problem of virtual camera control and we analyse a number of different problems in different virtual environments. Each of these scenarios is described through a set of complexity measures and, as a result of this analysis, a subset of scenarios...

  7. Dynamical effects and time scale in fission processes in nuclear collisions in the fermi energy range

    International Nuclear Information System (INIS)

    Colin, J.; Bocage, F.; Louvel, M.; Bellaize, N.; Bougault, R.; Brou, R.; Cussol, D.; Durand, D.; Genouin-Duhamel, E.; Lecolley, J.F.; Le Neindre, N.; Lopez, O.; Nguyen, A.D.; Peter, J.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Brun, C. le; Genoux-Lubain, A.

    1999-01-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn... o btained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distributions of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mid-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, authors observed two components: The first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, authors present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component authors extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component authors propose a scenario to explain such process and authors discuss the physical parameters which can be extracted

  8. Dynamical effects and time scale in fission processes in nuclear collisions in the Fermi energy range

    International Nuclear Information System (INIS)

    Colin, J.; Bocage, F.; Louvel, M.

    1999-10-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn...) obtained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distribution of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mi-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, we observed two components: the first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, we present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component we extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component we propose a scenario to explain such process and we discuss the physical parameters which can be extracted. (authors)

  9. Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

    Science.gov (United States)

    Gole, Vaibhav C.; Woodhouse, Rebecca; Caraguel, Charles; Moyle, Talia; Rault, Jean-Loup; Sexton, Margaret

    2016-01-01

    ABSTRACT The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates (n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA, ironA, and misL. There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella

  10. Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems.

    Science.gov (United States)

    Gole, Vaibhav C; Woodhouse, Rebecca; Caraguel, Charles; Moyle, Talia; Rault, Jean-Loup; Sexton, Margaret; Chousalkar, Kapil

    2017-03-01

    The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates ( n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA , ironA , and misL There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella serovars in

  11. Dynamics and genetic structure of Argentine ant supercolonies in their native range

    DEFF Research Database (Denmark)

    Vogel, Valérie; Pedersen, Jes S; d'Ettorre, Patrizia

    2009-01-01

    analyses revealed the presence of 11 supercolonies (width 1 to 515 m) over a 3-km transect. As in the introduced range, there was always strong aggression between but never within supercolonies. The genetic data were in perfect agreement with the behavioral tests, all nests being assigned to identical...... supercolonies with the different methods. There was strong genetic differentiation between supercolonies but no genetic differentiation among nests within supercolonies. We never found more than a single mitochondrial haplotype per supercolony, further supporting the view that supercolonies are closed breeding...

  12. Development and testing of a fast Fourier transform high dynamic-range spectral diagnostics for millimeter wave characterization

    International Nuclear Information System (INIS)

    Thoen, D. J.; Bongers, W. A.; Westerhof, E.; Baar, M. R. de; Berg, M. A. van den; Beveren, V. van; Goede, A. P. H.; Graswinckel, M. F.; Schueller, F. C.; Oosterbeek, J. W.; Buerger, A.; Hennen, B. A.

    2009-01-01

    A fast Fourier transform (FFT) based wide range millimeter wave diagnostics for spectral characterization of scattered millimeter waves in plasmas has been successfully brought into operation. The scattered millimeter waves are heterodyne downconverted and directly digitized using a fast analog-digital converter and a compact peripheral component interconnect computer. Frequency spectra are obtained by FFT in the time domain of the intermediate frequency signal. The scattered millimeter waves are generated during high power electron cyclotron resonance heating experiments on the TEXTOR tokamak and demonstrate the performance of the diagnostics and, in particular, the usability of direct digitizing and Fourier transformation of millimeter wave signals. The diagnostics is able to acquire 4 GHz wide spectra of signals in the range of 136-140 GHz. The rate of spectra is tunable and has been tested between 200 000 spectra/s with a frequency resolution of 100 MHz and 120 spectra/s with a frequency resolution of 25 kHz. The respective dynamic ranges are 52 and 88 dB. Major benefits of the new diagnostics are a tunable time and frequency resolution due to postdetection, near-real time processing of the acquired data. This diagnostics has a wider application in astrophysics, earth observation, plasma physics, and molecular spectroscopy for the detection and analysis of millimeter wave radiation, providing high-resolution spectra at high temporal resolution and large dynamic range.

  13. High Resolution and Large Dynamic Range Resonant Pressure Sensor Based on Q-Factor Measurement

    Science.gov (United States)

    Gutierrez, Roman C. (Inventor); Stell, Christopher B. (Inventor); Tang, Tony K. (Inventor); Vorperian, Vatche (Inventor); Wilcox, Jaroslava (Inventor); Shcheglov, Kirill (Inventor); Kaiser, William J. (Inventor)

    2000-01-01

    A pressure sensor has a high degree of accuracy over a wide range of pressures. Using a pressure sensor relying upon resonant oscillations to determine pressure, a driving circuit drives such a pressure sensor at resonance and tracks resonant frequency and amplitude shifts with changes in pressure. Pressure changes affect the Q-factor of the resonating portion of the pressure sensor. Such Q-factor changes are detected by the driving/sensing circuit which in turn tracks the changes in resonant frequency to maintain the pressure sensor at resonance. Changes in the Q-factor are reflected in changes of amplitude of the resonating pressure sensor. In response, upon sensing the changes in the amplitude, the driving circuit changes the force or strength of the electrostatic driving signal to maintain the resonator at constant amplitude. The amplitude of the driving signals become a direct measure of the changes in pressure as the operating characteristics of the resonator give rise to a linear response curve for the amplitude of the driving signal. Pressure change resolution is on the order of 10(exp -6) torr over a range spanning from 7,600 torr to 10(exp -6) torr. No temperature compensation for the pressure sensor of the present invention is foreseen. Power requirements for the pressure sensor are generally minimal due to the low-loss mechanical design of the resonating pressure sensor and the simple control electronics.

  14. [Range of Hip Joint Motion and Weight of Lower Limb Function under 3D Dynamic Marker].

    Science.gov (United States)

    Xia, Q; Zhang, M; Gao, D; Xia, W T

    2017-12-01

    To explore the range of reasonable weight coefficient of hip joint in lower limb function. When the hip joints of healthy volunteers under normal conditions or fixed at three different positions including functional, flexed and extension positions, the movements of lower limbs were recorded by LUKOtronic motion capture and analysis system. The degree of lower limb function loss was calculated using Fugl-Meyer lower limb function assessment form when the hip joints were fixed at the aforementioned positions. One-way analysis of variance and Tamhane's T2 method were used to proceed statistics analysis and calculate the range of reasonable weight coefficient of hip joint. There were significant differences between the degree of lower limb function loss when the hip joints fixed at flexed and extension positions and at functional position. While the differences between the degree of lower limb function loss when the hip joints fixed at flexed position and extension position had no statistical significance. In 95% confidence interval, the reasonable weight coefficient of hip joint in lower limb function was between 61.05% and 73.34%. Expect confirming the reasonable weight coefficient, the effects of functional and non-functional positions on the degree of lower limb function loss should also be considered for the assessment of hip joint function loss. Copyright© by the Editorial Department of Journal of Forensic Medicine

  15. An approach to understand incomplete fusion dynamics from recoil range distribution measurements

    International Nuclear Information System (INIS)

    Tali, Suhail A.; Kumar, Harish; Afzal Ansari, M.

    2016-01-01

    Britt and Quinton initially pointed out the incomplete fusion (ICF) signatures in the break-up of projectiles like 12 C, 14 N, and 16 O into α-clusters at ≈10 MeV/nucleon energies. Additional information was provided by Inamura et al. by performing the particle gamma coincidence experiment which significantly contributed in the understanding of ICF study. The interest to understand the ICF reaction dynamics for low Z projectiles (Z≤10) at energies ≈ 4-7MeV/nucleon has recently become an active area of research because of lack of any appropriate theoretical aspect, which may reproduce the experimental ICF data. At projectile energies above the Coulomb barrier, CF and ICF are dominant and competing reaction modes. For the imparted angular momentum ℓ < ℓ crit , the attractive nuclear potential is dominant, which may lead to the complete amalgamation of projectile with the target nucleus. However, for angular momentum ℓ> L crit , the projectile breaks into two parts one of them may fuse with the target nucleus, while the remainder moves as a spectator in forward direction with nearly the same velocity as that of incident projectile. The less excited composite system thus formed carries lower Forward Linear Momentum Transfer (FLMT) due to partial mass transferring from projectiles to the target nucleus compared to the compound nucleus formed via CF process

  16. Long-Range Vibrational Dynamics Are Directed by Watson-Crick Base Pairing in Duplex DNA.

    Science.gov (United States)

    Hithell, Gordon; Shaw, Daniel J; Donaldson, Paul M; Greetham, Gregory M; Towrie, Michael; Burley, Glenn A; Parker, Anthony W; Hunt, Neil T

    2016-05-05

    Ultrafast two-dimensional infrared (2D-IR) spectroscopy of a 15-mer A-T DNA duplex in solution has revealed structure-dependent vibrational coupling and energy transfer processes linking bases with the sugar-phosphate backbone. Duplex melting induces significant changes in the positions of off-diagonal peaks linking carbonyl and ring-stretching vibrational modes of the adenine and thymine bases with vibrations of the phosphate group and phosphodiester linkage. These indicate that Watson-Crick hydrogen bonding and helix formation lead to a unique vibrational coupling arrangement of base vibrational modes with those of the phosphate unit. On the basis of observations from time-resolved 2D-IR data, we conclude that rapid energy transfer processes occur between base and backbone, mediated by additional modes located on the deoxyribose moiety within the same nucleotide. These relaxation dynamics are insensitive to duplex melting, showing that efficient intramolecular energy relaxation to the solvent via the phosphate groups is the key to excess energy dissipation in both single- and double-stranded DNA.

  17. Application of a New Dynamic Heating System Model Using a Range of Common Control Strategies

    Directory of Open Access Journals (Sweden)

    Joshua Fong

    2016-06-01

    Full Text Available This research investigates the overall heating energy consumptions using various control strategies, secondary heat emitters, and primary plant for a building. Previous research has successfully demonstrated that a dynamic distributed heat emitter model embedded within a simplified third-order lumped parameter building model is capable of achieving improved results when compared to other commercially available modelling tools. With the enhanced ability to capture transient effects of emitter thermal capacity, this research studies the influence of control strategies and primary plant configurations on the rate of energy consumption of a heating system. Four alternative control strategies are investigated: zone feedback; weather-compensated; a combination of both of these methods; and thermostatic control. The plant alternative configurations consist of conventional boilers, biomass boilers, and heat pumps supporting radiator heating and underfloor heating. The performance of the model is tested on a primary school building and can be applied to any residential or commercial building with a heating system. Results show that the new methods reported offer greater detail and rigor in the conduct of building energy modelling.

  18. Performance of Hayabusa2 DCAM3-D Camera for Short-Range Imaging of SCI and Ejecta Curtain Generated from the Artificial Impact Crater Formed on Asteroid 162137 Ryugu (1999 JU3)

    Science.gov (United States)

    Ishibashi, K.; Shirai, K.; Ogawa, K.; Wada, K.; Honda, R.; Arakawa, M.; Sakatani, N.; Ikeda, Y.

    2017-07-01

    Deployable Camera 3-D (DCAM3-D) is a small high-resolution camera equipped on Deployable Camera 3 (DCAM3), one of the Hayabusa2 instruments. Hayabusa2 will explore asteroid 162137 Ryugu (1999 JU3) and conduct an impact experiment using a liner shooting device called Small Carry-on Impactor (SCI). DCAM3 will be detached from the Hayabusa2 spacecraft and observe the impact experiment. The purposes of the observation are to know the impact conditions, to estimate the surface structure of asteroid Ryugu, and to understand the physics of impact phenomena on low-gravity bodies. DCAM3-D requires high imaging performance because it has to image and detect multiple targets of different scale and radiance, i.e., the faint SCI before the shot from 1-km distance, the bright ejecta generated by the impact, and the asteroid. In this paper we report the evaluation of the performance of the CMOS imaging sensor and the optical system of DCAM3-D. We also describe the calibration of DCAM3-D. We confirmed that the imaging performance of DCAM3-D satisfies the required values to achieve the purposes of the observation.

  19. Nonlinear Dynamics of Ultrashort Long-Range Surface Plasmon Polariton Pulses in Gold Strip Waveguides

    DEFF Research Database (Denmark)

    Lysenko, Oleg; Bache, Morten; Olivier, Nicolas

    2016-01-01

    We study experimentally and theoretically nonlinear propagation of ultrashort long-range surface plasmon polaritons in gold strip waveguides. The nonlinear absorption of the plasmonic modes in the waveguides is measured with femtosecond pulses revealing a strong dependence of the third......-order nonlinear susceptibility of the gold core on the pulse duration and layer thickness. A comprehensive model for the pulse duration dependence of the third-order nonlinear susceptibility is developed on the basis of the nonlinear Schrödinger equation for plasmonic mode propagation in the waveguides....... The model accounts for the intrinsic delayed (noninstantaneous) nonlinearity of free electrons of gold as well as the thickness of the gold film and is experimentally verified. The obtained results are important for the development of active plasmonic and nanophotonic components....

  20. Climatic niche conservatism and the evolutionary dynamics in species range boundaries

    DEFF Research Database (Denmark)

    Olalla-Tárraga1, Miguel Á.; McInnes, Linsey; Bini, Luis M.

    2011-01-01

    Aim Comparative evidence for phylogenetic niche conservatism – the tendency for lineages to retain their ancestral niches over long time scales – has so far been mixed, depending on spatial and taxonomic scale. We quantify and compare conservatism in the climatic factors defining range boundaries...... conservatism, as expected from their greater physiological sensitivity and lower dispersal abilities. Location Global; continental land masses excluding Antarctica. Methods We used nearly complete global distributional databases to estimate the climatic niche conservatism in extant continental mammals...... and amphibians. We characterized the climatic niche of each species by using a suite of variables and separately investigate conservatism in each variable using both taxonomic and phylogenetic approaches. Finally, we explored the spatial, taxonomic and phylogenetic patterns in recent climatic niche evolution...

  1. A stochastic chemical dynamic approach to correlate autoimmunity and optimal vitamin-D range.

    Science.gov (United States)

    Roy, Susmita; Shrinivas, Krishna; Bagchi, Biman

    2014-01-01

    Motivated by several recent experimental observations that vitamin-D could interact with antigen presenting cells (APCs) and T-lymphocyte cells (T-cells) to promote and to regulate different stages of immune response, we developed a coarse grained but general kinetic model in an attempt to capture the role of vitamin-D in immunomodulatory responses. Our kinetic model, developed using the ideas of chemical network theory, leads to a system of nine coupled equations that we solve both by direct and by stochastic (Gillespie) methods. Both the analyses consistently provide detail information on the dependence of immune response to the variation of critical rate parameters. We find that although vitamin-D plays a negligible role in the initial immune response, it exerts a profound influence in the long term, especially in helping the system to achieve a new, stable steady state. The study explores the role of vitamin-D in preserving an observed bistability in the phase diagram (spanned by system parameters) of immune regulation, thus allowing the response to tolerate a wide range of pathogenic stimulation which could help in resisting autoimmune diseases. We also study how vitamin-D affects the time dependent population of dendritic cells that connect between innate and adaptive immune responses. Variations in dose dependent response of anti-inflammatory and pro-inflammatory T-cell populations to vitamin-D correlate well with recent experimental results. Our kinetic model allows for an estimation of the range of optimum level of vitamin-D required for smooth functioning of the immune system and for control of both hyper-regulation and inflammation. Most importantly, the present study reveals that an overdose or toxic level of vitamin-D or any steroid analogue could give rise to too large a tolerant response, leading to an inefficacy in adaptive immune function.

  2. A stochastic chemical dynamic approach to correlate autoimmunity and optimal vitamin-D range.

    Directory of Open Access Journals (Sweden)

    Susmita Roy

    Full Text Available Motivated by several recent experimental observations that vitamin-D could interact with antigen presenting cells (APCs and T-lymphocyte cells (T-cells to promote and to regulate different stages of immune response, we developed a coarse grained but general kinetic model in an attempt to capture the role of vitamin-D in immunomodulatory responses. Our kinetic model, developed using the ideas of chemical network theory, leads to a system of nine coupled equations that we solve both by direct and by stochastic (Gillespie methods. Both the analyses consistently provide detail information on the dependence of immune response to the variation of critical rate parameters. We find that although vitamin-D plays a negligible role in the initial immune response, it exerts a profound influence in the long term, especially in helping the system to achieve a new, stable steady state. The study explores the role of vitamin-D in preserving an observed bistability in the phase diagram (spanned by system parameters of immune regulation, thus allowing the response to tolerate a wide range of pathogenic stimulation which could help in resisting autoimmune diseases. We also study how vitamin-D affects the time dependent population of dendritic cells that connect between innate and adaptive immune responses. Variations in dose dependent response of anti-inflammatory and pro-inflammatory T-cell populations to vitamin-D correlate well with recent experimental results. Our kinetic model allows for an estimation of the range of optimum level of vitamin-D required for smooth functioning of the immune system and for control of both hyper-regulation and inflammation. Most importantly, the present study reveals that an overdose or toxic level of vitamin-D or any steroid analogue could give rise to too large a tolerant response, leading to an inefficacy in adaptive immune function.

  3. Seasonality in cholera dynamics: A rainfall-driven model explains the wide range of patterns in endemic areas

    Science.gov (United States)

    Baracchini, Theo; King, Aaron A.; Bouma, Menno J.; Rodó, Xavier; Bertuzzo, Enrico; Pascual, Mercedes

    2017-10-01

    Seasonal patterns in cholera dynamics exhibit pronounced variability across geographical regions, showing single or multiple peaks at different times of the year. Although multiple hypotheses related to local climate variables have been proposed, an understanding of this seasonal variation remains incomplete. The historical Bengal region, which encompasses the full range of cholera's seasonality observed worldwide, provides a unique opportunity to gain insights on underlying environmental drivers. Here, we propose a mechanistic, rainfall-temperature driven, stochastic epidemiological model which explicitly accounts for the fluctuations of the aquatic reservoir, and analyze with this model the historical dataset of cholera mortality in the Bengal region. Parameters are inferred with a recently developed sequential Monte Carlo method for likelihood maximization in partially observed Markov processes. Results indicate that the hydrological regime is a major driver of the seasonal dynamics of cholera. Rainfall tends to buffer the propagation of the disease in wet regions due to the longer residence times of water in the environment and an associated dilution effect, whereas it enhances cholera resurgence in dry regions. Moreover, the dynamics of the environmental water reservoir determine whether the seasonality is unimodal or bimodal, as well as its phase relative to the monsoon. Thus, the full range of seasonal patterns can be explained based solely on the local variation of rainfall and temperature. Given the close connection between cholera seasonality and environmental conditions, a deeper understanding of the underlying mechanisms would allow the better management and planning of public health policies with respect to climate variability and climate change.

  4. Cameras in mobile phones

    Science.gov (United States)

    Nummela, Ville; Viinikanoja, Jarkko; Alakarhu, Juha

    2006-04-01

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

  5. Thermal Cameras and Applications

    DEFF Research Database (Denmark)

    Gade, Rikke; Moeslund, Thomas B.

    2014-01-01

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

  6. High-resolution and large dynamic range nanomechanical mapping in tapping-mode atomic force microscopy

    International Nuclear Information System (INIS)

    Sahin, Ozgur; Erina, Natalia

    2008-01-01

    High spatial resolution imaging of material properties is an important task for the continued development of nanomaterials and studies of biological systems. Time-varying interaction forces between the vibrating tip and the sample in a tapping-mode atomic force microscope contain detailed information about the elastic, adhesive, and dissipative response of the sample. We report real-time measurement and analysis of the time-varying tip-sample interaction forces with recently introduced torsional harmonic cantilevers. With these measurements, high-resolution maps of elastic modulus, adhesion force, energy dissipation, and topography are generated simultaneously in a single scan. With peak tapping forces as low as 0.6 nN, we demonstrate measurements on blended polymers and self-assembled molecular architectures with feature sizes at 1, 10, and 500 nm. We also observed an elastic modulus measurement range of four orders of magnitude (1 MPa to 10 GPa) for a single cantilever under identical feedback conditions, which can be particularly useful for analyzing heterogeneous samples with largely different material components.

  7. Dynamic mechanical behaviour and dislocation substructure evolution of Inconel 718 over wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woei-Shyan, E-mail: wslee@mail.ncku.edu.tw [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Chi-Feng [National Center for High-Performance Computing, Hsin-Shi Tainan County 744, Taiwan (China); Chen, Tao-Hsing [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan (China); Chen, Hong-Wei [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2011-07-25

    A compressive split-Hopkinson pressure bar and transmission electron microscope (TEM) are used to investigate the mechanical behaviour and microstructural evolution of Inconel 718 at strain rates ranging from 1000 to 5000 s{sup -1} and temperatures between -150 and 550 deg. C. The results show that the flow stress increases with an increasing strain rate or a reducing temperature. The strain rate effect is particularly pronounced at strain rates greater than 3000 s{sup -1} and a deformation temperature of -150 deg. C. A significant thermal softening effect occurs at temperatures between -150 and 25 deg. C. The microstructural observations reveal that the strengthening effect in deformed Inconel 718 alloy is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature. By contrast, the dislocation cell size decreases with increasing strain rate, but increases with increasing temperature. It is shown that the correlation between the flow stress, the dislocation density and the dislocation cell size is well described by the Bailey-Hirsch constitutive equations.

  8. Dynamical Quantum Phase Transitions in Spin Chains with Long-Range Interactions: Merging Different Concepts of Nonequilibrium Criticality

    Science.gov (United States)

    Žunkovič, Bojan; Heyl, Markus; Knap, Michael; Silva, Alessandro

    2018-03-01

    We theoretically study the dynamics of a transverse-field Ising chain with power-law decaying interactions characterized by an exponent α , which can be experimentally realized in ion traps. We focus on two classes of emergent dynamical critical phenomena following a quantum quench from a ferromagnetic initial state: The first one manifests in the time-averaged order parameter, which vanishes at a critical transverse field. We argue that such a transition occurs only for long-range interactions α ≤2 . The second class corresponds to the emergence of time-periodic singularities in the return probability to the ground-state manifold which is obtained for all values of α and agrees with the order parameter transition for α ≤2 . We characterize how the two classes of nonequilibrium criticality correspond to each other and give a physical interpretation based on the symmetry of the time-evolved quantum states.

  9. Fast negative feedback enables mammalian auditory nerve fibers to encode a wide dynamic range of sound intensities.

    Directory of Open Access Journals (Sweden)

    Mark Ospeck

    Full Text Available Mammalian auditory nerve fibers (ANF are remarkable for being able to encode a 40 dB, or hundred fold, range of sound pressure levels into their firing rate. Most of the fibers are very sensitive and raise their quiescent spike rate by a small amount for a faint sound at auditory threshold. Then as the sound intensity is increased, they slowly increase their spike rate, with some fibers going up as high as ∼300 Hz. In this way mammals are able to combine sensitivity and wide dynamic range. They are also able to discern sounds embedded within background noise. ANF receive efferent feedback, which suggests that the fibers are readjusted according to the background noise in order to maximize the information content of their auditory spike trains. Inner hair cells activate currents in the unmyelinated distal dendrites of ANF where sound intensity is rate-coded into action potentials. We model this spike generator compartment as an attenuator that employs fast negative feedback. Input current induces rapid and proportional leak currents. This way ANF are able to have a linear frequency to input current (f-I curve that has a wide dynamic range. The ANF spike generator remains very sensitive to threshold currents, but efferent feedback is able to lower its gain in response to noise.

  10. Intra- and interobserver reliability of gray scale/dynamic range evaluation of ultrasonography using a standardized phantom

    International Nuclear Information System (INIS)

    Lee, Song; Choi, Joon Il; Park, Michael Yong; Yeo, Dong Myung; Byun, Jae Young; Jung, Seung Eun; Rha, Sung Eun; Oh, Soon Nam; Lee, Young Joon

    2014-01-01

    To evaluate intra- and interobserver reliability of the gray scale/dynamic range of the phantom image evaluation of ultrasonography using a standardized phantom, and to assess the effect of interactive education on the reliability. Three radiologists (a resident, and two board-certified radiologists with 2 and 7 years of experience in evaluating ultrasound phantom images) performed the gray scale/dynamic range test for an ultrasound machine using a standardized phantom. They scored the number of visible cylindrical structures of varying degrees of brightness and made a pass or fail decision. First, they scored 49 phantom images twice from a 2010 survey with limited knowledge of phantom images. After this, the radiologists underwent two hours of interactive education for the phantom images and scored another 91 phantom images from a 2011 survey twice. Intra- and interobserver reliability before and after the interactive education session were analyzed using K analyses. Before education, the K-value for intraobserver reliability for the radiologist with 7 years of experience, 2 years of experience, and the resident was 0.386, 0.469, and 0.465, respectively. After education, the K-values were improved (0.823, 0.611, and 0.711, respectively). For interobserver reliability, the K-value was also better after the education for the 3 participants (0.067, 0.002, and 0.547 before education; 0.635, 0.667, and 0.616 after education, respectively). The intra- and interobserver reliability of the gray scale/dynamic range was fair to substantial. Interactive education can improve reliability. For more reliable results, double- checking of phantom images by multiple reviewers is recommended.

  11. An electrically driven terahertz metamaterial diffractive modulator with more than 20 dB of dynamic range

    International Nuclear Information System (INIS)

    Karl, N.; Reichel, K.; Mendis, R.; Mittleman, D. M.; Chen, H.-T.; Taylor, A. J.; Brener, I.; Benz, A.; Reno, J. L.

    2014-01-01

    We design and experimentally demonstrate a switchable diffraction grating for terahertz modulation based on planar active metamaterials, where a Schottky gate structure is implemented to tune the metamaterial resonances in real-time via the application of an external voltage bias. The diffraction grating is formed by grouping the active split-ring resonators into an array of independent columns with alternate columns biased. We observe off-axis diffraction over a wide frequency band in contrast to the narrow-band resonances, which permits operation of the device as a relatively high-speed, wide-bandwidth, high-contrast modulator, with more than 20 dB of dynamic range

  12. TOPLAR: Time of Flight with Larmor Precessions - or - How to extend the dynamic range of NSE spectrometers

    International Nuclear Information System (INIS)

    Van Well, A.A.; Bleuel, M.; Pappas, C.

    2011-01-01

    Neutron Spin Echo (NSE) spectrometers typically cover a dynamic range of three orders of magnitude at a given wavelength. At long Fourier times the limits are given by the homogeneity of precession fields. At short Fourier times, the quasi-elastic approximation and the NSE formalism mark a methodological limit. We propose to overcome this limitation and by combining Time Of Flight with Larmor precession to extend the capabilities of Neutron Spin Echo spectrometers towards short Fourier times. TOFLAR should be easily implemented on NSE spectrometers equipped with a chopper system such as IN15 or the planned WASP. (authors)

  13. Optimization of nonimaging focusing heliostat in dynamic correction of astigmatism for a wide range of incident angles.

    Science.gov (United States)

    Chong, Kok-Keong

    2010-05-15

    To overcome astigmatism has always been a great challenge in designing a heliostat capable of focusing the sunlight on a small receiver throughout the year. In this Letter, a nonimaging focusing heliostat with a dynamic adjustment of facet mirrors in a group manner has been analyzed for optimizing the astigmatic correction in a wide range of incident angles. This what is to the author's knowledge a new heliostat is not only designed to serve the purpose of concentrating sunlight to several hundreds of suns, but also to significantly reduce the variation of the solar flux distribution with the incident angle.

  14. When and where to move: Dynamic occupancy models explain the range dynamics of a food nomadic bird under climate and land cover change.

    Science.gov (United States)

    Kalle, Riddhika; Ramesh, Tharmalingam; Downs, Colleen T

    2018-01-01

    Globally, long-term research is critical to monitor the responses of tropical species to climate and land cover change at the range scale. Citizen science surveys can reveal the long-term persistence of poorly known nomadic tropical birds occupying fragmented forest patches. We applied dynamic occupancy models to 13 years (2002-2014) of citizen science-driven presence/absence data on Cape parrot (Poicephalus robustus), a food nomadic bird endemic to South Africa. We modeled its underlying range dynamics as a function of resource distribution, and change in climate and land cover through the estimation of colonization and extinction patterns. The range occupancy of Cape parrot changed little over time (ψ = 0.75-0.83) because extinction was balanced by recolonization. Yet, there was considerable regional variability in occupancy and detection probability increased over the years. Colonizations increased with warmer temperature and area of orchards, thus explaining their range shifts southeastwards in recent years. Although colonizations were higher in the presence of nests and yellowwood trees (Afrocarpus and Podocarpus spp.), the extinctions in small forest patches (≤227 ha) and during low precipitation (≤41 mm) are attributed to resource constraints and unsuitable climatic conditions. Loss of indigenous forest cover and artificial lake/water bodies increased extinction probabilities of Cape parrot. The land use matrix (fruit farms, gardens, and cultivations) surrounding forest patches provides alternative food sources, thereby facilitating spatiotemporal colonization and extinction in the human-modified matrix. Our models show that Cape parrots are vulnerable to extreme climatic conditions such as drought which is predicted to increase under climate change. Therefore, management of optimum sized high-quality forest patches is essential for long-term survival of Cape parrot populations. Our novel application of dynamic occupancy models to long-term citizen

  15. Tissue oximetry: a comparison of mean values of regional tissue saturation, reproducibility and dynamic range of four NIRS-instruments on the human forearm

    DEFF Research Database (Denmark)

    Hyttel-Sørensen, Simon; Sorensen, Line C; Riera, Joan

    2011-01-01

    We compared absolute values of regional tissue hemoglobin saturation (StO(2)), reproducibility, and dynamic range of four different instruments on the forearm of adults. The sensors were repositioned 10 times on each subject. Dynamic range was estimated by exercise with subsequent arterial occlus...

  16. Quantum gases. Observation of many-body dynamics in long-range tunneling after a quantum quench.

    Science.gov (United States)

    Meinert, Florian; Mark, Manfred J; Kirilov, Emil; Lauber, Katharina; Weinmann, Philipp; Gröbner, Michael; Daley, Andrew J; Nägerl, Hanns-Christoph

    2014-06-13

    Quantum tunneling is at the heart of many low-temperature phenomena. In strongly correlated lattice systems, tunneling is responsible for inducing effective interactions, and long-range tunneling substantially alters many-body properties in and out of equilibrium. We observe resonantly enhanced long-range quantum tunneling in one-dimensional Mott-insulating Hubbard chains that are suddenly quenched into a tilted configuration. Higher-order tunneling processes over up to five lattice sites are observed as resonances in the number of doubly occupied sites when the tilt per site is tuned to integer fractions of the Mott gap. This forms a basis for a controlled study of many-body dynamics driven by higher-order tunneling and demonstrates that when some degrees of freedom are frozen out, phenomena that are driven by small-amplitude tunneling terms can still be observed. Copyright © 2014, American Association for the Advancement of Science.

  17. Characterization of a wide dynamic-range, radiation-tolerant charge-digitizer asic for monitoring of Beam losses

    CERN Document Server

    Guido Venturini, G G; Dehning, B; Kayal, M

    2012-01-01

    An Application Specific Integrated Circuit (ASIC) has been designed and fabricated to provide a compact solution to digitize current signals from ionization chambers and diamond detectors, employed as beam loss monitors at CERN and several other high energy physics facilities. The circuit topology has been devised to accept positive and negative currents, to have a wide dynamic range (above 120 dB), withstand radiation levels over 10 Mrad and offer different modes of operation, covering a broad range of applications. Furthermore, an internal conversion reference is employed in the digitization, to provide an accurate absolute measurement. This paper discusses the detailed characterization of the first prototype: linearity, radiation tolerance and temperature dependence of the conversion, as well as implications and system-level considerations regarding its use for beam instrumentation applications in a high energy physics facility.

  18. Demonstration of the CDMA-mode CAOS smart camera.

    Science.gov (United States)

    Riza, Nabeel A; Mazhar, Mohsin A

    2017-12-11

    Demonstrated is the code division multiple access (CDMA)-mode coded access optical sensor (CAOS) smart camera suited for bright target scenarios. Deploying a silicon CMOS sensor and a silicon point detector within a digital micro-mirror device (DMD)-based spatially isolating hybrid camera design, this smart imager first engages the DMD starring mode with a controlled factor of 200 high optical attenuation of the scene irradiance to provide a classic unsaturated CMOS sensor-based image for target intelligence gathering. Next, this CMOS sensor provided image data is used to acquire a focused zone more robust un-attenuated true target image using the time-modulated CDMA-mode of the CAOS camera. Using four different bright light test target scenes, successfully demonstrated is a proof-of-concept visible band CAOS smart camera operating in the CDMA-mode using up-to 4096 bits length Walsh design CAOS pixel codes with a maximum 10 KHz code bit rate giving a 0.4096 seconds CAOS frame acquisition time. A 16-bit analog-to-digital converter (ADC) with time domain correlation digital signal processing (DSP) generates the CDMA-mode images with a 3600 CAOS pixel count and a best spatial resolution of one micro-mirror square pixel size of 13.68 μm side. The CDMA-mode of the CAOS smart camera is suited for applications where robust high dynamic range (DR) imaging is needed for un-attenuated un-spoiled bright light spectrally diverse targets.

  19. Static, dynamic and electronic properties of expanded fluid mercury in the metal-nonmetal transition range. An ab initio study

    International Nuclear Information System (INIS)

    CalderIn, L; Gonzalez, L E; Gonzalez, D J

    2011-01-01

    Fluid Hg undergoes a metal-nonmetal (M-NM) transition when expanded toward a density of around 9 g cm -3 . We have performed ab initio molecular dynamics simulations for several thermodynamic states around the M-NM transition range and the associated static, dynamic and electronic properties have been analyzed. The calculated static structure shows a good agreement with the available experimental data. It is found that the volume expansion decreases the number of nearest neighbors from 10 (near the triple point) to around 8 at the M-NM transition region. Moreover, these neighbors are arranged into two subshells and the decrease in the number of neighbors occurs in the inner subshell. The calculated dynamic structure factors agree fairly well with their experimental counterparts obtained by inelastic x-ray scattering experiments, which display inelastic side peaks. The derived dispersion relation exhibits some positive dispersion for all the states, although its value around the M-NM transition region is not as marked as suggested by the experiment. We have also calculated the electronic density of states, which shows the appearance of a gap at a density of around 8.3 g cm -3 . (paper)

  20. Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Khalilian, Alireza; Kang, Shin-Won

    2016-02-20

    In this paper, we proposed an interdigitated capacitor (IDC)-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt's dye (R-dye). These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC)] and N,N-Dimethylacetamide (DMAC) solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE) by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance.

  1. Modeling a color-rendering operator for high dynamic range images using a cone-response function

    Science.gov (United States)

    Choi, Ho-Hyoung; Kim, Gi-Seok; Yun, Byoung-Ju

    2015-09-01

    Tone-mapping operators are the typical algorithms designed to produce visibility and the overall impression of brightness, contrast, and color of high dynamic range (HDR) images on low dynamic range (LDR) display devices. Although several new tone-mapping operators have been proposed in recent years, the results of these operators have not matched those of the psychophysical experiments based on the human visual system. A color-rendering model that is a combination of tone-mapping and cone-response functions using an XYZ tristimulus color space is presented. In the proposed method, the tone-mapping operator produces visibility and the overall impression of brightness, contrast, and color in HDR images when mapped onto relatively LDR devices. The tone-mapping resultant image is obtained using chromatic and achromatic colors to avoid well-known color distortions shown in the conventional methods. The resulting image is then processed with a cone-response function wherein emphasis is placed on human visual perception (HVP). The proposed method covers the mismatch between the actual scene and the rendered image based on HVP. The experimental results show that the proposed method yields an improved color-rendering performance compared to conventional methods.

  2. High Dynamic Range Imaging at the Quantum Limit with Single Photon Avalanche Diode-Based Image Sensors †

    Science.gov (United States)

    Mattioli Della Rocca, Francescopaolo

    2018-01-01

    This paper examines methods to best exploit the High Dynamic Range (HDR) of the single photon avalanche diode (SPAD) in a high fill-factor HDR photon counting pixel that is scalable to megapixel arrays. The proposed method combines multi-exposure HDR with temporal oversampling in-pixel. We present a silicon demonstration IC with 96 × 40 array of 8.25 µm pitch 66% fill-factor SPAD-based pixels achieving >100 dB dynamic range with 3 back-to-back exposures (short, mid, long). Each pixel sums 15 bit-planes or binary field images internally to constitute one frame providing 3.75× data compression, hence the 1k frames per second (FPS) output off-chip represents 45,000 individual field images per second on chip. Two future projections of this work are described: scaling SPAD-based image sensors to HDR 1 MPixel formats and shrinking the pixel pitch to 1–3 µm. PMID:29641479

  3. Fast, Highly-Sensitive, and Wide-Dynamic-Range Interdigitated Capacitor Glucose Biosensor Using Solvatochromic Dye-Containing Sensing Membrane

    Directory of Open Access Journals (Sweden)

    Md. Rajibur Rahaman Khan

    2016-02-01

    Full Text Available In this paper, we proposed an interdigitated capacitor (IDC-based glucose biosensor to measure different concentrations of glucose from 1 μM to 1 M. We studied four different types of solvatochromic dyes: Auramine O, Nile red, Rhodamine B, and Reichardt’s dye (R-dye. These dyes were individually incorporated into a polymer [polyvinyl chloride (PVC] and N,N-Dimethylacetamide (DMAC solution to make the respective dielectric/sensing materials. To the best of our knowledge, we report for the first time an IDC glucose biosensing system utilizing a solvatochromic-dye-containing sensing membrane. These four dielectric or sensing materials were individually placed into the interdigitated electrode (IDE by spin coating to make four IDC glucose biosensing elements. The proposed IDC glucose biosensor has a high sensing ability over a wide dynamic range and its sensitivity was about 23.32 mV/decade. It also has fast response and recovery times of approximately 7 s and 5 s, respectively, excellent reproducibility with a standard deviation of approximately 0.023, highly stable sensing performance, and real-time monitoring capabilities. The proposed IDC glucose biosensor was compared with an IDC, potentiometric, FET, and fiber-optic glucose sensor with respect to response time, dynamic range width, sensitivity, and linearity. We observed that the designed IDC glucose biosensor offered excellent performance.

  4. Increasing dynamic range of a fibre Bragg grating edge-filtering interrogator with a proportional control loop

    International Nuclear Information System (INIS)

    Stan, Nikola; Bailey, D C; Chadderdon, S L; Selfridge, R H; Schultz, S M; Webb, S; Zikry, M; Peters, K J

    2014-01-01

    We present a fibre Bragg grating (FBG) interrogator that uses a microcontroller board and a tunable optical filter in a proportional control loop to increase dynamic range and achieve high strain sensitivity. It is an edge-filtering interrogator with added proportional control loop that locks the operating wavelength to the mid-reflection point on the FBG spectrum. The interrogator separates low-frequency (LF) components of strain and measures them with extended dynamic range, while at the same time measuring high-frequency (HF) strain without loss in strain sensitivity. In this paper, we describe the implementation of the interrogator and analyse the characteristics of individual components, such as the speed and voltage resolution of the microcontroller and the tunable optical filter. We measure the performance of the proportional control loop at frequencies up to 1 kHz and characterize the system using control theory. We illustrate the limitation of the conventional interrogator to measure strains greater than 40 μϵ and demonstrate successful application of the proposed interrogator for simultaneous measurement of 450 μϵ LF strain at 50 Hz superimposed with 32 kHz HF strain. (paper)

  5. Design of Microwave Camera for Breast Cancer Detection

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy

    2008-01-01

    is then used to reconstruct an image, which consists of a spatial distribution of the complex permittivity in the imaging domain. Using this image the cancer tissue can be detected due to its dielectric property contrast compared to normal tissue. The instrument employs a multichannel high sensitive...... superheterodyne architecture, enabling parallel coherent measurements. In this way, mechanical scanning, which is commonly used in measurements of an electromagnetic field distribution, is avoided. The system presented is the first reported 3D microwave breast imaging camera with parallel signal detection....... The hardware operates in the frequency range 0.3 – 3 GHz. The noise floor is below -140 dBm over the bandwidth of the system. The dynamic range depends on the available incident power range and is limited by the channel to channel isolation of 140 dB. The work presented in this thesis encompasses a wide range...

  6. ISSLS PRIZE IN BIOENGINEERING SCIENCE 2018: dynamic imaging of degenerative spondylolisthesis reveals mid-range dynamic lumbar instability not evident on static clinical radiographs.

    Science.gov (United States)

    Dombrowski, Malcolm E; Rynearson, Bryan; LeVasseur, Clarissa; Adgate, Zach; Donaldson, William F; Lee, Joon Y; Aiyangar, Ameet; Anderst, William J

    2018-04-01

    Degenerative spondylolisthesis (DS) in the setting of symptomatic lumbar spinal stenosis is commonly treated with spinal fusion in addition to decompression with laminectomy. However, recent studies have shown similar clinical outcomes after decompression alone, suggesting that a subset of DS patients may not require spinal fusion. Identification of dynamic instability could prove useful for predicting which patients are at higher risk of post-laminectomy destabilization necessitating fusion. The goal of this study was to determine if static clinical radiographs adequately characterize dynamic instability in patients with lumbar degenerative spondylolisthesis (DS) and to compare the rotational and translational kinematics in vivo during continuous dynamic flexion activity in DS versus asymptomatic age-matched controls. Seven patients with symptomatic single level lumbar DS (6 M, 1 F; 66 ± 5.0 years) and seven age-matched asymptomatic controls (5 M, 2 F age 63.9 ± 6.4 years) underwent biplane radiographic imaging during continuous torso flexion. A volumetric model-based tracking system was used to track each vertebra in the radiographic images using subject-specific 3D bone models from high-resolution computed tomography (CT). In vivo continuous dynamic sagittal rotation (flexion/extension) and AP translation (slip) were calculated and compared to clinical measures of intervertebral flexion/extension and AP translation obtained from standard lateral flexion/extension radiographs. Static clinical radiographs underestimate the degree of AP translation seen on dynamic in vivo imaging (1.0 vs 3.1 mm; p = 0.03). DS patients demonstrated three primary motion patterns compared to a single kinematic pattern in asymptomatic controls when analyzing continuous dynamic in vivo imaging. 3/7 (42%) of patients with DS demonstrated aberrant mid-range motion. Continuous in vivo dynamic imaging in DS reveals a spectrum of aberrant motion with significantly greater

  7. Advanced CCD camera developments

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-11-15

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

  8. Gamma camera system

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  9. Sexual segregation in juvenile New Zealand sea lion foraging ranges: implications for intraspecific competition, population dynamics and conservation.

    Directory of Open Access Journals (Sweden)

    Elaine S Leung

    Full Text Available Sexual segregation (sex differences in spatial organisation and resource use is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ sea lion (Phocarctos hookeri, a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account

  10. Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges.

    Science.gov (United States)

    Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

    2018-04-01

    Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

  11. Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges

    Science.gov (United States)

    Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

    2018-04-01

    Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

  12. Viability after myocardial infarction: can it be assessed within five minutes by low-dose dynamic iodine-123-iodophenylpentadecanoic acid imaging with a multicrystal gamma camera?

    Science.gov (United States)

    Murray, G L; Schad, N; Bush, A J

    1997-04-01

    Although positron emission tomography (PET) assesses myocardial viability (V) accurately, a rapid, inexpensive substitute is needed. Therefore, the authors developed a low-dose (1 mCi) Iodine-123-Iodophenylpentadecanoic Acid (IPPA) myocardial viability scan requiring analysis of only the first three minutes of data acquired at rest with a standard multicrystal gamma camera. Twenty-one patients > 2 weeks after myocardial infarction (MI) (24 MIs, 10 anterior, 14 inferoposterior, 21 akinetic or dyskinetic) had cardiac catheterization and resting IPPA imaging. V was determined by either transmural myocardial biopsy during coronary bypass surgery (12 patients, 14 MIs) or reinjection tomographic thallium scan (9 patients, 10 MIs), and 50% of MIs were viable. The IPPA variables analyzed were: time to initial left ventricular (LV) uptake in the region of interest (ROI), the ratio of three-minute uptake in the ROI to three-minute LV uptake, three-minute clearing (counts/pixel) in the ROI (decrease in IPPA after initial uptake), and three-minute accumulation (increase in IPPA after initial uptake) in the ROI. Rules for detecting V were generated and applied to 10 healthy volunteers to determine normalcy. While three-minute uptake in nonviable MIs was only 67% of volunteers (P or = 13.5 counts/pixel in 10/12 (83%) of viable MIs, and IPPA accumulation > or = 6.75 counts/pixel identified one more viable MI, for a sensitivity for V of 11/12 (92%), with a specificity of 11/12 (92%), and a 100% normalcy rate. The authors conclude low-dose IPPA (five-minute acquisition with analysis of the first three minutes of data) has potential for providing rapid, inexpensive V data after MI. Since newer multicrystal cameras are mobile, IPPA scans can be done in emergency rooms or coronary care units generating information that might be useful in decisions regarding thrombolysis, angioplasty, or bypass surgery.

  13. Divergence-ratio axi-vision camera (Divcam): A distance mapping camera

    International Nuclear Information System (INIS)

    Iizuka, Keigo

    2006-01-01

    A novel distance mapping camera the divergence-ratio axi-vision camera (Divcam) is proposed. The decay rate of the illuminating light with distance due to the divergence of the light is used as means of mapping the distance. Resolutions of 10 mm over a range of meters and 0.5 mm over a range of decimeters were achieved. The special features of this camera are its high resolution real-time operation, simplicity, compactness, light weight, portability, and yet low fabrication cost. The feasibility of various potential applications is also included

  14. Wide Dynamic Range Multiband Infrared Radiometer for In-Fire Measurements of Wildland Fire Radiant Flux Density

    Science.gov (United States)

    Kremens, R.; Dickinson, M. B.; Hardy, C.; Skowronski, N.; Ellicott, E. A.; Schroeder, W.

    2016-12-01

    We have developed a wide dynamic range (24-bit) data acquisition system for collection of radiant flux density (FRFD) data from wildland fires. The data collection subsystem was designed as an Arduino `shield' and incorporates a 24-bit analog-to-digital converter, precision voltage reference, real time clock, microSD card interface, audible annuciator and interface for various digital communication interfaces (RS232, I2C, SPI, etc.). The complete radiometer system consists of our custom-designed `shield', a commercially available Arduino MEGA computer circuit board and a thermopile sensor -amplifier daughter board. Software design and development is greatly assisted by the availability of a library of public-domain, user-implemented software. The daughter board houses a 5-band radiometer using thermopiles designed for this experiment (Dexter Research Corp., Dexter, MI) to allow determination of the total FRFD from the fire (using a wide band thermopile with a KRS-5 window, 0.1 - 30 um), the FRFD as would be received by an orbital asset like MODIS (3.95 um center wavelength (CWL) and 10.95 CWL, corresponding to MODIS bands 21/22 and 31, respectively) and wider bandpass (0.1-5.5 um and 8-14 um) corresponding to the FRFD recorded by `MWIR' and `LWIR' imaging systems. We required a very wide dynamic range system in order to be able to record the flux density from `cold' ground before the fire, through the `hot' flaming combustion stage, to the `cool' phase after passage of the fire front. The recording dynamic range required (with reasonable resolution at the lowest temperatures) is on the order of 106, which is not currently available in commercial instrumentation at a price point, size or feature set that is suitable for wildland fire investigations. The entire unit, along with rechargeable battery power supply is housed in a fireproof aluminum chassis box, which is then mounted on a mast at a height of 5 - 7 m above the fireground floor. We will report initial

  15. Low-power low-noise mixed-mode VLSI ASIC for infinite dynamic range imaging applications

    Science.gov (United States)

    Turchetta, Renato; Hu, Y.; Zinzius, Y.; Colledani, C.; Loge, A.

    1998-11-01

    Solid state solutions for imaging are mainly represented by CCDs and, more recently, by CMOS imagers. Both devices are based on the integration of the total charge generated by the impinging radiation, with no processing of the single photon information. The dynamic range of these devices is intrinsically limited by the finite value of noise. Here we present the design of an architecture which allows efficient, in-pixel, noise reduction to a practically zero level, thus allowing infinite dynamic range imaging. A detailed calculation of the dynamic range is worked out, showing that noise is efficiently suppressed. This architecture is based on the concept of single-photon counting. In each pixel, we integrate both the front-end, low-noise, low-power analog part and the digital part. The former consists of a charge preamplifier, an active filter for optimal noise bandwidth reduction, a buffer and a threshold comparator, and the latter is simply a counter, which can be programmed to act as a normal shift register for the readout of the counters' contents. Two different ASIC's based on this concept have been designed for different applications. The first one has been optimized for silicon edge-on microstrips detectors, used in a digital mammography R and D project. It is a 32-channel circuit, with a 16-bit binary static counter.It has been optimized for a relatively large detector capacitance of 5 pF. Noise has been measured to be equal to 100 + 7*Cd (pF) electron rms with the digital part, showing no degradation of the noise performances with respect to the design values. The power consumption is 3.8mW/channel for a peaking time of about 1 microsecond(s) . The second circuit is a prototype for pixel imaging. The total active area is about (250 micrometers )**2. The main differences of the electronic architecture with respect to the first prototype are: i) different optimization of the analog front-end part for low-capacitance detectors, ii) in- pixel 4-bit comparator

  16. The MVACS Robotic Arm Camera

    Science.gov (United States)

    Keller, H. U.; Hartwig, H.; Kramm, R.; Koschny, D.; Markiewicz, W. J.; Thomas, N.; Fernades, M.; Smith, P. H.; Reynolds, R.; Lemmon, M. T.; Weinberg, J.; Marcialis, R.; Tanner, R.; Boss, B. J.; Oquest, C.; Paige, D. A.

    2001-08-01

    The Robotic Arm Camera (RAC) is one of the key instruments newly developed for the Mars Volatiles and Climate Surveyor payload of the Mars Polar Lander. This lightweight instrument employs a front lens with variable focus range and takes images at distances from 11 mm (image scale 1:1) to infinity. Color images with a resolution of better than 50 μm can be obtained to characterize the Martian soil. Spectral information of nearby objects is retrieved through illumination with blue, green, and red lamp sets. The design and performance of the camera are described in relation to the science objectives and operation. The RAC uses the same CCD detector array as the Surface Stereo Imager and shares the readout electronics with this camera. The RAC is mounted at the wrist of the Robotic Arm and can characterize the contents of the scoop, the samples of soil fed to the Thermal Evolved Gas Analyzer, the Martian surface in the vicinity of the lander, and the interior of trenches dug out by the Robotic Arm. It can also be used to take panoramic images and to retrieve stereo information with an effective baseline surpassing that of the Surface Stereo Imager by about a factor of 3.

  17. Radiometric calibration of wide-field camera system with an application in astronomy

    Science.gov (United States)

    Vítek, Stanislav; Nasyrova, Maria; Stehlíková, Veronika

    2017-09-01

    Camera response function (CRF) is widely used for the description of the relationship between scene radiance and image brightness. Most common application of CRF is High Dynamic Range (HDR) reconstruction of the radiance maps of imaged scenes from a set of frames with different exposures. The main goal of this work is to provide an overview of CRF estimation algorithms and compare their outputs with results obtained under laboratory conditions. These algorithms, typically designed for multimedia content, are unfortunately quite useless with astronomical image data, mostly due to their nature (blur, noise, and long exposures). Therefore, we propose an optimization of selected methods to use in an astronomical imaging application. Results are experimentally verified on the wide-field camera system using Digital Single Lens Reflex (DSLR) camera.

  18. A Cherenkov camera with integrated electronics based on the 'Smart Pixel' concept

    International Nuclear Information System (INIS)

    Bulian, Norbert; Hirsch, Thomas; Hofmann, Werner; Kihm, Thomas; Kohnle, Antje; Panter, Michael; Stein, Michael

    2000-01-01

    An option for the cameras of the HESS telescopes, the concept of a modular camera based on 'Smart Pixels' was developed. A Smart Pixel contains the photomultiplier, the high voltage supply for the photomultiplier, a dual-gain sample-and-hold circuit with a 14 bit dynamic range, a time-to-voltage converter, a trigger discriminator, trigger logic to detect a coincidence of X=1...7 neighboring pixels, and an analog ratemeter. The Smart Pixels plug into a common backplane which provides power, communicates trigger signals between neighboring pixels, and holds a digital control bus as well as an analog bus for multiplexed readout of pixel signals. The performance of the Smart Pixels has been studied using a 19-pixel test camera

  19. Computational imaging with multi-camera time-of-flight systems

    KAUST Repository

    Shrestha, Shikhar

    2016-07-11

    Depth cameras are a ubiquitous technology used in a wide range of applications, including robotic and machine vision, human computer interaction, autonomous vehicles as well as augmented and virtual reality. In this paper, we explore the design and applications of phased multi-camera time-of-flight (ToF) systems. We develop a reproducible hardware system that allows for the exposure times and waveforms of up to three cameras to be synchronized. Using this system, we analyze waveform interference between multiple light sources in ToF applications and propose simple solutions to this problem. Building on the concept of orthogonal frequency design, we demonstrate state-of-the-art results for instantaneous radial velocity capture via Doppler time-of-flight imaging and we explore new directions for optically probing global illumination, for example by de-scattering dynamic scenes and by non-line-of-sight motion detection via frequency gating. © 2016 ACM.

  20. Shoulder Dynamic Control Ratio and Rotation Range of Motion in Female Junior Elite Handball Players and Controls.

    Science.gov (United States)

    van Cingel, Robert; Habets, Bas; Willemsen, Linn; Staal, Bart

    2018-03-01

    To compare glenohumeral range of motion and shoulder rotator muscle strength in healthy female junior elite handball players and controls. Cross-sectional case-control study. Sports medical center. Forty elite female handball players and 30 controls active in nonoverhead sports participated in this study. Passive external rotator (ER), internal rotator (IR), and total range of motion (TROM) of the dominant and nondominant arm were examined with a goniometer. An isokinetic dynamometer was used to evaluate concentric and eccentric rotator muscle strength at 60 and 120 degrees/s with dynamic control ratio (DCR = ERecc:IRcon) as the main outcome parameter. Except for the ER range of motion in the nondominant arm, no significant differences were found between groups for IR, ER of the dominant arm, and the TROM. Within the handball group, the side-to-side difference for IR of the dominant arm was -1.4 degrees. The ER and the TROM of the dominant arm were significantly larger, 6.3 and 4.9 degrees, respectively. For both groups, the DCR values were above 1 and no significant differences were found between the dominant and nondominant arm. The DCR values in the handball group were significantly lower than in the control group. Based on the adopted definitions for muscle imbalance, glenohumeral internal range of motion deficit and TROM deficit our elite female handball players seem not at risk for shoulder injuries. Prospective studies are needed to support the belief that a DCR below 1 places the shoulder at risk for injury.

  1. Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus: a comparison between central and range edge populations.

    Directory of Open Access Journals (Sweden)

    Rita M Araújo

    Full Text Available Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity of population growth rate showed that fertility elements had a small contribution to λ(s that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental

  2. Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus): a comparison between central and range edge populations.

    Science.gov (United States)

    Araújo, Rita M; Serrão, Ester A; Sousa-Pinto, Isabel; Åberg, Per

    2014-01-01

    Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s)) of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s) much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity) of population growth rate showed that fertility elements had a small contribution to λ(s) that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental variability and

  3. Spectral counting assessment of protein dynamic range in cerebrospinal fluid following depletion with plasma-designed immunoaffinity columns

    Directory of Open Access Journals (Sweden)

    Borg Jacques

    2011-06-01

    Full Text Available Abstract Background In cerebrospinal fluid (CSF, which is a rich source of biomarkers for neurological diseases, identification of biomarkers requires methods that allow reproducible detection of low abundance proteins. It is therefore crucial to decrease dynamic range and improve assessment of protein abundance. Results We applied LC-MS/MS to compare the performance of two CSF enrichment techniques that immunodeplete either albumin alone (IgYHSA or 14 high-abundance proteins (IgY14. In order to estimate dynamic range of proteins identified, we measured protein abundance with APEX spectral counting method. Both immunodepletion methods improved the number of low-abundance proteins detected (3-fold for IgYHSA, 4-fold for IgY14. The 10 most abundant proteins following immunodepletion accounted for 41% (IgY14 and 46% (IgYHSA of CSF protein content, whereas they accounted for 64% in non-depleted samples, thus demonstrating significant enrichment of low-abundance proteins. Defined proteomics experiment metrics showed overall good reproducibility of the two immunodepletion methods and MS analysis. Moreover, offline peptide fractionation in IgYHSA sample allowed a 4-fold increase of proteins identified (520 vs. 131 without fractionation, without hindering reproducibility. Conclusions The novelty of this study was to show the advantages and drawbacks of these methods side-to-side. Taking into account the improved detection and potential loss of non-target proteins following extensive immunodepletion, it is concluded that both depletion methods combined with spectral counting may be of interest before further fractionation, when searching for CSF biomarkers. According to the reliable identification and quantitation obtained with APEX algorithm, it may be considered as a cheap and quick alternative to study sample proteomic content.

  4. Review of Calibration Methods for Scheimpflug Camera

    Directory of Open Access Journals (Sweden)

    Cong Sun

    2018-01-01

    Full Text Available The Scheimpflug camera offers a wide range of applications in the field of typical close-range photogrammetry, particle image velocity, and digital image correlation due to the fact that the depth-of-view of Scheimpflug camera can be greatly extended according to the Scheimpflug condition. Yet, the conventional calibration methods are not applicable in this case because the assumptions used by classical calibration methodologies are not valid anymore for cameras undergoing Scheimpflug condition. Therefore, various methods have been investigated to solve the problem over the last few years. However, no comprehensive review exists that provides an insight into recent calibration methods of Scheimpflug cameras. This paper presents a survey of recent calibration methods of Scheimpflug cameras with perspective lens, including the general nonparametric imaging model, and analyzes in detail the advantages and drawbacks of the mainstream calibration models with respect to each other. Real data experiments including calibrations, reconstructions, and measurements are performed to assess the performance of the models. The results reveal that the accuracies of the RMM, PLVM, PCIM, and GNIM are basically equal, while the accuracy of GNIM is slightly lower compared with the other three parametric models. Moreover, the experimental results reveal that the parameters of the tangential distortion are likely coupled with the tilt angle of the sensor in Scheimpflug calibration models. The work of this paper lays the foundation of further research of Scheimpflug cameras.

  5. Multi-Angle Snowflake Camera Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

  6. Characterization of SWIR cameras by MRC measurements

    Science.gov (United States)

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

    2014-05-01

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

  7. Versatile ultrafast pump-probe imaging with high sensitivity CCD camera

    OpenAIRE

    Pezeril , Thomas; Klieber , Christoph; Temnov , Vasily; Huntzinger , Jean-Roch; Anane , Abdelmadjid

    2012-01-01

    International audience; A powerful imaging technique based on femtosecond time-resolved measurements with a high dynamic range, commercial CCD camera is presented. Ultrafast phenomena induced by a femtosecond laser pump are visualized through the lock-in type acquisition of images recorded by a femtosecond laser probe. This technique allows time-resolved measurements of laser excited phenomena at multiple probe wavelengths (spectrometer mode) or conventional imaging of the sample surface (ima...

  8. Cooling rate and size effects on the medium-range structure of multicomponent oxide glasses simulated by molecular dynamics

    International Nuclear Information System (INIS)

    Tilocca, Antonio

    2013-01-01

    A set of molecular dynamics simulations were performed to investigate the effect of cooling rate and system size on the medium-range structure of melt-derived multicomponent silicate glasses, represented by the quaternary 45S5 Bioglass composition. Given the significant impact of the glass degradation on applications of these materials in biomedicine and nuclear waste disposal, bulk structural features which directly affect the glass dissolution process are of particular interest. Connectivity of the silicate matrix, ion clustering and nanosegregation, distribution of ring and chain structural patterns represent critical features in this context, which can be directly extracted from the models. A key issue is represented by the effect of the computational approach on the corresponding glass models, especially in light of recent indications questioning the suitability of conventional MD approaches (that is, involving melt-and-quench of systems containing ∼10 3 atoms at cooling rates of 5-10 K/ps) when applied to model these glasses. The analysis presented here compares MD models obtained with conventional and nonconventional cooling rates and system sizes, highlighting the trend and range of convergence of specific structural features in the medium range. The present results show that time-consuming computational approaches involving much lower cooling rates and/or significantly larger system sizes are in most cases not necessary in order to obtain a reliable description of the medium-range structure of multicomponent glasses. We identify the convergence range for specific properties and use them to discuss models of several glass compositions for which a possible influence of cooling-rate or size effects had been previously hypothesized. The trends highlighted here represent an important reference to obtain reliable models of multicomponent glasses and extract converged medium-range structural features which affect the glass degradation and thus their application

  9. Cooling rate and size effects on the medium-range structure of multicomponent oxide glasses simulated by molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Tilocca, Antonio [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)

    2013-09-21

    A set of molecular dynamics simulations were performed to investigate the effect of cooling rate and system size on the medium-range structure of melt-derived multicomponent silicate glasses, represented by the quaternary 45S5 Bioglass composition. Given the significant impact of the glass degradation on applications of these materials in biomedicine and nuclear waste disposal, bulk structural features which directly affect the glass dissolution process are of particular interest. Connectivity of the silicate matrix, ion clustering and nanosegregation, distribution of ring and chain structural patterns represent critical features in this context, which can be directly extracted from the models. A key issue is represented by the effect of the computational approach on the corresponding glass models, especially in light of recent indications questioning the suitability of conventional MD approaches (that is, involving melt-and-quench of systems containing ∼10{sup 3} atoms at cooling rates of 5-10 K/ps) when applied to model these glasses. The analysis presented here compares MD models obtained with conventional and nonconventional cooling rates and system sizes, highlighting the trend and range of convergence of specific structural features in the medium range. The present results show that time-consuming computational approaches involving much lower cooling rates and/or significantly larger system sizes are in most cases not necessary in order to obtain a reliable description of the medium-range structure of multicomponent glasses. We identify the convergence range for specific properties and use them to discuss models of several glass compositions for which a possible influence of cooling-rate or size effects had been previously hypothesized. The trends highlighted here represent an important reference to obtain reliable models of multicomponent glasses and extract converged medium-range structural features which affect the glass degradation and thus their

  10. Commercialization of radiation tolerant camera

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-01

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

  11. Commercialization of radiation tolerant camera

    International Nuclear Information System (INIS)

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

    1999-12-01

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

  12. Typical effects of laser dazzling CCD camera

    Science.gov (United States)

    Zhang, Zhen; Zhang, Jianmin; Shao, Bibo; Cheng, Deyan; Ye, Xisheng; Feng, Guobin

    2015-05-01

    In this article, an overview of laser dazzling effect to buried channel CCD camera is given. The CCDs are sorted into staring and scanning types. The former includes the frame transfer and interline transfer types. The latter includes linear and time delay integration types. All CCDs must perform four primary tasks in generating an image, which are called charge generation, charge collection, charge transfer and charge measurement. In camera, the lenses are needed to input the optical signal to the CCD sensors, in which the techniques for erasing stray light are used. And the electron circuits are needed to process the output signal of CCD, in which many electronic techniques are used. The dazzling effects are the conjunct result of light distribution distortion and charge distribution distortion, which respectively derive from the lens and the sensor. Strictly speaking, in lens, the light distribution is not distorted. In general, the lens are so well designed and fabricated that its stray light can be neglected. But the laser is of much enough intensity to make its stray light obvious. In CCD image sensors, laser can induce a so large electrons generation. Charges transfer inefficiency and charges blooming will cause the distortion of the charge distribution. Commonly, the largest signal outputted from CCD sensor is restricted by capability of the collection well of CCD, and can't go beyond the dynamic range for the subsequent electron circuits maintaining normal work. So the signal is not distorted in the post-processing circuits. But some techniques in the circuit can make some dazzling effects present different phenomenon in final image.

  13. Phylogenetic fields through time: temporal dynamics of geographical co-occurrence and phylogenetic structure within species ranges.

    Science.gov (United States)

    Villalobos, Fabricio; Carotenuto, Francesco; Raia, Pasquale; Diniz-Filho, José Alexandre F

    2016-04-05

    Species co-occur with different sets of other species across their geographical distribution, which can be either closely or distantly related. Such co-occurrence patterns and their phylogenetic structure within individual species ranges represent what we call the species phylogenetic fields (PFs). These PFs allow investigation of the role of historical processes--speciation, extinction and dispersal--in shaping species co-occurrence patterns, in both extinct and extant species. Here, we investigate PFs of large mammalian species during the last 3 Myr, and how these correlate with trends in diversification rates. Using the fossil record, we evaluate species' distributional and co-occurrence patterns along with their phylogenetic structure. We apply a novel Bayesian framework on fossil occurrences to estimate diversification rates through time. Our findings highlight the effect of evolutionary processes and past climatic changes on species' distributions and co-occurrences. From the Late Pliocene to the Recent, mammal species seem to have responded in an individualistic manner to climate changes and diversification dynamics, co-occurring with different sets of species from different lineages across their geographical ranges. These findings stress the difficulty of forecasting potential effects of future climate changes on biodiversity. © 2016 The Author(s).

  14. Himalayan ibex (Capra ibex sibirica habitat suitability and range resource dynamics in the Central Karakorum National Park, Pakistan

    Directory of Open Access Journals (Sweden)

    Garee Khan

    2016-07-01

    Full Text Available The study investigates Himalayan ibex (Capra ibex sibirica and their range resource condition within the preferred habitat in the Central Karakoram National Park, Pakistan. We apply ecological niche factor analysis (ENFA using 110 ibex sighting data and 6 key biophysical variables describing the habitat conditions and produce habitat suitability and maps with GIS and statistical tool (BioMapper. The modeling results of specialization factor shows some limitation for ibex over the use of slope, elevation, vegetation types and ruggedness. The habitat area selection for the ibex is adjusted to the ibex friendly habitat available conditions. The model results predicted suitable habitat for ibex in certain places, where field observation was never recorded. The range resource dynamics depict a large area that comes under the alpine meadows has the highest seasonal productivity, assessed by remote sensing based fortnightly vegetation condition data of the last 11 years. These meadows are showing browning trend over the years, attributable to grazing practices or climate conditions. At lower elevation, there are limited areas with suitable dry steppes, which may cause stress on ibex, especially during winter.

  15. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Kang, Shin-Won

    2016-11-09

    In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R² is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry-Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.

  16. Higher order moments of the matter distribution in scale-free cosmological simulations with large dynamic range

    Science.gov (United States)

    Lucchin, Francesco; Matarrese, Sabino; Melott, Adrian L.; Moscardini, Lauro

    1994-01-01

    We calculate reduced moments (xi bar)(sub q) of the matter density fluctuations, up to order q = 5, from counts in cells produced by particle-mesh numerical simulations with scale-free Gaussian initial conditions. We use power-law spectra P(k) proportional to k(exp n) with indices n = -3, -2, -1, 0, 1. Due to the supposed absence of characteristic times or scales in our models, all quantities are expected to depend on a single scaling variable. For each model, the moments at all times can be expressed in terms of the variance (xi bar)(sub 2), alone. We look for agreement with the hierarchical scaling ansatz, according to which ((xi bar)(sub q)) proportional to ((xi bar)(sub 2))(exp (q - 1)). For n less than or equal to -2 models, we find strong deviations from the hierarchy, which are mostly due to the presence of boundary problems in the simulations. A small, residual signal of deviation from the hierarchical scaling is however also found in n greater than or equal to -1 models. The wide range of spectra considered and the large dynamic range, with careful checks of scaling and shot-noise effects, allows us to reliably detect evolution away from the perturbation theory result.

  17. Nonlinear complexity of random visibility graph and Lempel-Ziv on multitype range-intensity interacting financial dynamics

    Science.gov (United States)

    Zhang, Yali; Wang, Jun

    2017-09-01

    In an attempt to investigate the nonlinear complex evolution of financial dynamics, a new financial price model - the multitype range-intensity contact (MRIC) financial model, is developed based on the multitype range-intensity interacting contact system, in which the interaction and transmission of different types of investment attitudes in a stock market are simulated by viruses spreading. Two new random visibility graph (VG) based analyses and Lempel-Ziv complexity (LZC) are applied to study the complex behaviors of return time series and the corresponding random sorted series. The VG method is the complex network theory, and the LZC is a non-parametric measure of complexity reflecting the rate of new pattern generation of a series. In this work, the real stock market indices are considered to be comparatively studied with the simulation data of the proposed model. Further, the numerical empirical study shows the similar complexity behaviors between the model and the real markets, the research confirms that the financial model is reasonable to some extent.

  18. The Effective Dynamic Ranges for Glaucomatous Visual Field Progression With Standard Automated Perimetry and Stimulus Sizes III and V.

    Science.gov (United States)

    Wall, Michael; Zamba, Gideon K D; Artes, Paul H

    2018-01-01

    It has been shown that threshold estimates below approximately 20 dB have little effect on the ability to detect visual field progression in glaucoma. We aimed to compare stimulus size V to stimulus size III, in areas of visual damage, to confirm these findings by using (1) a different dataset, (2) different techniques of progression analysis, and (3) an analysis to evaluate the effect of censoring on mean deviation (MD). In the Iowa Variability in Perimetry Study, 120 glaucoma subjects were tested every 6 months for 4 years with size III SITA Standard and size V Full Threshold. Progression was determined with three complementary techniques: pointwise linear regression (PLR), permutation of PLR, and linear regression of the MD index. All analyses were repeated on "censored'' datasets in which threshold estimates below a given criterion value were set to equal the criterion value. Our analyses confirmed previous observations that threshold estimates below 20 dB contribute much less to visual field progression than estimates above this range. These findings were broadly similar with stimulus sizes III and V. Censoring of threshold values < 20 dB has relatively little impact on the rates of visual field progression in patients with mild to moderate glaucoma. Size V, which has lower retest variability, performs at least as well as size III for longitudinal glaucoma progression analysis and appears to have a larger useful dynamic range owing to the upper sensitivity limit being higher.

  19. A Novel Realization of Low-Power and Low-Distortion Multiplier Circuit with Improved Dynamic Range

    Directory of Open Access Journals (Sweden)

    Ali Naderi Saatlo

    2017-01-01

    Full Text Available A novel topology of four-quadrant analog multiplier circuit is presented in this paper. The voltage mode technique is employed to design the circuit in CMOS technology. The dynamic input and output ranges of the circuit are improved owing to the fact that the circuit works in the saturation region not in weak inversion. Also the proposed multiplier is suitable for low voltage operation and its power consumption is relatively low. In order to verify the performance of the proposed circuit, performance of the circuit affected by second order effects including transistor mismatch and mobility reduction is analyzed in detail. It will be shown that any conceivable mismatch in the transistor parameters leads to second harmonic distortion. Additionally, the effect of mobility reduction in the third harmonic distortion will be computed. In order to simulate the circuit, Cadence and HSPICE software are used with TSMC level 49 (BSIM3v3 parameters for 0.18 μm CMOS technology, where under supply voltage of 1.5 V, total power consumption is 44 µW, the corresponding average nonlinearity remains as low as 1 %, and the input range of the circuit is ± 400 mV.

  20. Selective-imaging camera

    Science.gov (United States)

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

    2015-05-01

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