WorldWideScience

Sample records for low-speed ccd camera

  1. CCD Camera

    Science.gov (United States)

    Roth, Roger R.

    1983-01-01

    A CCD camera capable of observing a moving object which has varying intensities of radiation eminating therefrom and which may move at varying speeds is shown wherein there is substantially no overlapping of successive images and wherein the exposure times and scan times may be varied independently of each other.

  2. CCD Luminescence Camera

    Science.gov (United States)

    Janesick, James R.; Elliott, Tom

    1987-01-01

    New diagnostic tool used to understand performance and failures of microelectronic devices. Microscope integrated to low-noise charge-coupled-device (CCD) camera to produce new instrument for analyzing performance and failures of microelectronics devices that emit infrared light during operation. CCD camera also used to indentify very clearly parts that have failed where luminescence typically found.

  3. 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.

  4. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

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

  5. Vacuum compatible miniature CCD camera head

    Science.gov (United States)

    Conder, Alan D.

    2000-01-01

    A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close(0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

  6. CCD characterization for a range of color cameras

    NARCIS (Netherlands)

    Withagen, P.J.; Groen, F.C.A.; Schutte, K.

    2005-01-01

    CCD cameras are widely used for remote sensing and image processing applications. However, most cameras are produced to create nice images, not to do accurate measurements. Post processing operations such as gamma adjustment and automatic gain control are incorporated in the camera. When a (CCD) cam

  7. Event Pileup in AXAF's ACIS CCD Camera

    Science.gov (United States)

    McNamara, Brian R.

    1998-01-01

    AXAF's high resolution mirrors will focus a point source near the optical axis to a spot that is contained within a radius of about two pixels on the ACIS Charge Coupled Devices (CCD) camera. Because of the small spot size, the accuracy to which fluxes and spectral energy distributions of bright point sources can be measured will be degrad3ed by event pileup. Event pileup occurs when two or more X-ray photons arrive simultaneously in a single detection cell on a CCD readout frame. When pileup occurs, ACIS's event detection algorithm registers the photons as a single X-ray event. The pulse height channel of the event will correspond to an energy E approximately E-1 + E-2...E-n, where n is the number of photons registered per detection cell per readout frame. As a result, pileup artificially hardens the observed spectral energy distribution. I will discuss the effort at the AXAF Science Center Lo calibrate pileup in ACIS using focused, nearly monochromatic X-ray source. I will discuss techniques for modeling and correcting pileup effects in polychromatic spectra.

  8. Recent advances in ultrasensitive CCD camera technology

    Science.gov (United States)

    Christenson, Mark; Guntupalli, Ravi K.

    2002-06-01

    The current trend in diagnostic assay development is toward the use of smaller and smaller biological samples. The assay will then be required to identify a trace amount of a particular protein, nucleic acid or chemical species within a complex mixture of molecules. Due to the inherently low amount of analyte in these samples, a very sensitive detection device is required to make the measurement. In addition, many assays are becoming multi-parametric in order to reduce cost and lower the turnaround time of analysis. The increase in sample numbers can be dealt with by highly parallel analysis of samples either in an array format or in adjacent micro-channels. Another factor pushing the development toward highly parallel analysis is the desire to use high throughput methods to do measurements on multiple source samples in parallel. The highly parallel analysis can be readily achieved with imaging methods in contrast to the point measurements usually employed in current instrumentation. This paper will examine the recent trends in scientific grade CCD based imaging systems that are being driven by new development in CCD sensors, intensifiers and camera designs.

  9. Evryscope Robotilter automated camera / ccd alignment system

    Science.gov (United States)

    Ratzloff, Jeff K.; Law, Nicholas M.; Fors, Octavi; Ser, Daniel d.; Corbett, Henry T.

    2016-08-01

    We have deployed a new class of telescope, the Evryscope, which opens a new parameter space in optical astronomy - the ability to detect short time scale events across the entire sky simultaneously. The system is a gigapixel-scale array camera with an 8000 sq. deg. field of view, 13 arcsec per pixel sampling, and the ability to detect objects brighter than g = 16 in each 2-minute exposure. The Evryscope is designed to find transiting exoplanets around exotic stars, as well as detect nearby supernovae and provide continuous records of distant relativistic explosions like gamma-ray-bursts. The Evryscope uses commercially available CCDs and optics; the machine and assembly tolerances inherent in the mass production of these parts introduce problematic variations in the lens / CCD alignment which degrades image quality. We have built an automated alignment system (Robotilters) to solve this challenge. In this paper we describe the Robotilter system, mechanical and software design, image quality improvement, and current status.

  10. A comparison of colour micrographs obtained with a charged couple devise (CCD) camera and a 35-mm camera

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Smedegaard, Jesper; Jensen, Peter Koch

    2005-01-01

    ophthalmology, colour CCD camera, colour film, digital imaging, resolution, micrographs, histopathology, light microscopy......ophthalmology, colour CCD camera, colour film, digital imaging, resolution, micrographs, histopathology, light microscopy...

  11. Mid-IR image acquisition using a standard CCD camera

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Sørensen, Knud Palmelund; Pedersen, Christian

    2010-01-01

    Direct image acquisition in the 3-5 µm range is realized using a standard CCD camera and a wavelength up-converter unit. The converter unit transfers the image information to the NIR range were state-of-the-art cameras exist.......Direct image acquisition in the 3-5 µm range is realized using a standard CCD camera and a wavelength up-converter unit. The converter unit transfers the image information to the NIR range were state-of-the-art cameras exist....

  12. BUNDLE ADJUSTMENTS CCD CAMERA CALIBRATION BASED ON COLLINEARITY EQUATION

    Institute of Scientific and Technical Information of China (English)

    Liu Changying; Yu Zhijing; Che Rensheng; Ye Dong; Huang Qingcheng; Yang Dingning

    2004-01-01

    The solid template CCD camera calibration method of bundle adjustments based on collinearity equation is presented considering the characteristics of space large-dimension on-line measurement. In the method, a more comprehensive camera model is adopted which is based on the pinhole model extended with distortions corrections. In the process of calibration, calibration precision is improved by imaging at different locations in the whole measurement space, multi-imaging at the same location and bundle adjustments optimization. The calibration experiment proves that the calibration method is able to fulfill calibration requirement of CCD camera applied to vision measurement.

  13. Low cost CCD camera protection against neutron radiation damage.

    Science.gov (United States)

    Kok, J G M

    2005-01-01

    At a radiotherapy department cancer patients are treated with high energy electron and photon beams. These beams are produced by a linear accelerator. A closed circuit television system is used to monitor patients during treatment. Although CCD cameras are rather resistant to stray radiation, they are damaged by the low flux of neutrons which are produced by the linac as a side effect. PVC can be used to reduce damage to CCD cameras induced by neutron radiation. A box with 6 cm thick walls will extend the life of the camera at least by a factor of two. A PVC neutron shield is inexpensive. PVC is easy to obtain and the box is simple to construct. A similar box made out of PE will not reduce neutron damage to a CCD camera. Although PE is a good medium to moderate faster neutrons, thereby reducing some of the bulk defects, it will not capture thermal neutrons which induce surface damage.

  14. Printed circuit board for a CCD camera head

    Science.gov (United States)

    Conder, Alan D.

    2002-01-01

    A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close (0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

  15. CCD Color Camera Characterization for Image Measurements

    NARCIS (Netherlands)

    Withagen, P.J.; Groen, F.C.A.; Schutte, K.

    2007-01-01

    In this article, we will analyze a range of different types of cameras for its use in measurements. We verify a general model of a charged coupled device camera using experiments. This model includes gain and offset, additive and multiplicative noise, and gamma correction. It is shown that for sever

  16. Multi-digital Still Cameras with CCD

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-jing; LONG Zai-chuan; XIONG Ping; HUAN Yao-xiong

    2006-01-01

    Digital still camera is a completely typical tool for capturing the digital images. With the development of IC technology and optimization-algorithm, the performance of digital still cameras(DSCs) will be more and more powerful in the world. But can we obtain the more and better info using the combined information from the multi-digital still camera? The answer is yes by some experiments. By using multi-DSC at different angles, the various 3-D informations of the object are obtained.

  17. CCD emulator design for LSST camera

    Science.gov (United States)

    Lu, W.; O'Connor, P.; Fried, J.; Kuczewski, J.

    2016-07-01

    As part of the LSST project, a comprehensive CCD emulator that operates three CCDs simultaneously has been developed for testing multichannel readout electronics. Based on an Altera Cyclone V FPGA for timing and control, the emulator generates 48 channels of simulated video waveform in response to appropriate sequencing of parallel and serial clocks. Two 256Mb serial memory chips are adopted for storage of arbitrary grayscale images. The arbitrary image or fixed pattern image can be generated from the emulator in triple as three real CCDs perform, for qualifying and testing the LSST 3-stripe Science Raft Electronics Board (REB) simultaneously. Using the method of comparator threshold scanning, all 24 parallel clocks and 24 serial clocks from the REB are qualified for sequence, duration and level before the video signal is generated. In addition, 66 channels of input bias and voltages are sampled through the multi-channel ADC to verify that correct values are applied to the CCD. In addition, either a Gigabit Ethernet connector or USB bus can be used to control and read back from the emulator board. A user-friendly PC software package has been developed for controlling and communicating with the emulator.

  18. A new method to evaluate imaging quality of CCD cameras

    Institute of Scientific and Technical Information of China (English)

    LI Wen-juan; DU Hai-hui; DAI Jing-min; CHEN Ying-hang

    2005-01-01

    In order to evaluate the imaging quality of CCD cameras fully and rapidly,the minimum resolvable contrast (MRC) is presented in this paper and the system of measuring MRC is constructed as well,in which two integrating spheres are proposed to illuminate two sides of the target respectively.The variable contrast can be obtained by regulating the luminance of integrating spheres. Experimental results indicate that the error of measuring luminance is within ±0.3 cd/m2,MRC rises with the increase of the spatial frequency.The experimental results show that the method proposed is an effective approach to evaluate the imaging quality of CCD cameras.

  19. A luminescence imaging system based on a CCD camera

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.; Markey, B.G.

    1997-01-01

    to photographic systems, in order to obtain spatially resolved data. However, the former option is extremely expensive and it is difficult to obtain quantitative data from the latter. This paper describes the use of a CCD camera for imaging both thermoluminescence and optically stimulated luminescence. The system...... described here has a maximum spatial resolution of 17 mu m; though this may be varied under software control to alter the signal-to-noise ratio. The camera has been mounted on a Riso automated TL/OSL reader, and both the reader and the CCD are under computer control. In the near u.v and blue part...

  20. Visual enhancement of laparoscopic nephrectomies using the 3-CCD camera

    Science.gov (United States)

    Crane, Nicole J.; Kansal, Neil S.; Dhanani, Nadeem; Alemozaffar, Mehrdad; Kirk, Allan D.; Pinto, Peter A.; Elster, Eric A.; Huffman, Scott W.; Levin, Ira W.

    2006-02-01

    Many surgical techniques are currently shifting from the more conventional, open approach towards minimally invasive laparoscopic procedures. Laparoscopy results in smaller incisions, potentially leading to less postoperative pain and more rapid recoveries . One key disadvantage of laparoscopic surgery is the loss of three-dimensional assessment of organs and tissue perfusion. Advances in laparoscopic technology include high-definition monitors for improved visualization and upgraded single charge coupled device (CCD) detectors to 3-CCD cameras, to provide a larger, more sensitive color palette to increase the perception of detail. In this discussion, we further advance existing laparoscopic technology to create greater enhancement of images obtained during radical and partial nephrectomies in which the assessment of tissue perfusion is crucial but limited with current 3-CCD cameras. By separating the signals received by each CCD in the 3-CCD camera and by introducing a straight forward algorithm, rapid differentiation of renal vessels and perfusion is accomplished and could be performed real time. The newly acquired images are overlaid onto conventional images for reference and comparison. This affords the surgeon the ability to accurately detect changes in tissue oxygenation despite inherent limitations of the visible light image. Such additional capability should impact procedures in which visual assessment of organ vitality is critical.

  1. A USB 2.0 computer interface for the UCO/Lick CCD cameras

    Science.gov (United States)

    Wei, Mingzhi; Stover, Richard J.

    2004-09-01

    The new UCO/Lick Observatory CCD camera uses a 200 MHz fiber optic cable to transmit image data and an RS232 serial line for low speed bidirectional command and control. Increasingly RS232 is a legacy interface supported on fewer computers. The fiber optic cable requires either a custom interface board that is plugged into the mainboard of the image acquisition computer to accept the fiber directly or an interface converter that translates the fiber data onto a widely used standard interface. We present here a simple USB 2.0 interface for the UCO/Lick camera. A single USB cable connects to the image acquisition computer and the camera's RS232 serial and fiber optic cables plug into the USB interface. Since most computers now support USB 2.0 the Lick interface makes it possible to use the camera on essentially any modern computer that has the supporting software. No hardware modifications or additions to the computer are needed. The necessary device driver software has been written for the Linux operating system which is now widely used at Lick Observatory. The complete data acquisition software for the Lick CCD camera is running on a variety of PC style computers as well as an HP laptop.

  2. A New Technique for CCD Camera Auto-Calibration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel feature-round-based coplanar drone for the CCD camera auto-calibration is designed. Based on the ellipse similarity, an ellipse recognition algorithm is proposed. The experiment indicates the calibration error is less than 0.4 pixel.

  3. High frame rate CCD camera with fast optical shutter

    Energy Technology Data Exchange (ETDEWEB)

    Yates, G.J.; McDonald, T.E. Jr. [Los Alamos National Lab., NM (United States); Turko, B.T. [Lawrence Berkeley National Lab., CA (United States)

    1998-09-01

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

  4. CCD camera automatic calibration technology and ellipse recognition algorithm

    Institute of Scientific and Technical Information of China (English)

    Changku Sun; Xiaodong Zhang; Yunxia Qu

    2005-01-01

    A novel two-dimensional (2D) pattern used in camera calibration is presented. With one feature circle located at the center, an array of circles is photo-etched on this pattern. An ellipse recognition algorithm is proposed to implement the acquisition of interest calibration points without human intervention. According to the circle arrangement of the pattern, the relation between three-dimensional (3D) and 2D coordinates of these points can be established automatically and accurately. These calibration points are computed for intrinsic parameters calibration of charge-coupled device (CCD) camera with Tsai method. A series of experiments have shown that the algorithm is robust and reliable with the calibration error less than 0.4 pixel. This new calibration pattern and ellipse recognition algorithm can be widely used in computer vision.

  5. CCD Camera Lens Interface for Real-Time Theodolite Alignment

    Science.gov (United States)

    Wake, Shane; Scott, V. Stanley, III

    2012-01-01

    Theodolites are a common instrument in the testing, alignment, and building of various systems ranging from a single optical component to an entire instrument. They provide a precise way to measure horizontal and vertical angles. They can be used to align multiple objects in a desired way at specific angles. They can also be used to reference a specific location or orientation of an object that has moved. Some systems may require a small margin of error in position of components. A theodolite can assist with accurately measuring and/or minimizing that error. The technology is an adapter for a CCD camera with lens to attach to a Leica Wild T3000 Theodolite eyepiece that enables viewing on a connected monitor, and thus can be utilized with multiple theodolites simultaneously. This technology removes a substantial part of human error by relying on the CCD camera and monitors. It also allows image recording of the alignment, and therefore provides a quantitative means to measure such error.

  6. Differences in glance behavior between drivers using a rearview camera, parking sensor system, both technologies, or no technology during low-speed parking maneuvers.

    Science.gov (United States)

    Kidd, David G; McCartt, Anne T

    2016-02-01

    This study characterized the use of various fields of view during low-speed parking maneuvers by drivers with a rearview camera, a sensor system, a camera and sensor system combined, or neither technology. Participants performed four different low-speed parking maneuvers five times. Glances to different fields of view the second time through the four maneuvers were coded along with the glance locations at the onset of the audible warning from the sensor system and immediately after the warning for participants in the sensor and camera-plus-sensor conditions. Overall, the results suggest that information from cameras and/or sensor systems is used in place of mirrors and shoulder glances. Participants with a camera, sensor system, or both technologies looked over their shoulders significantly less than participants without technology. Participants with cameras (camera and camera-plus-sensor conditions) used their mirrors significantly less compared with participants without cameras (no-technology and sensor conditions). Participants in the camera-plus-sensor condition looked at the center console/camera display for a smaller percentage of the time during the low-speed maneuvers than participants in the camera condition and glanced more frequently to the center console/camera display immediately after the warning from the sensor system compared with the frequency of glances to this location at warning onset. Although this increase was not statistically significant, the pattern suggests that participants in the camera-plus-sensor condition may have used the warning as a cue to look at the camera display. The observed differences in glance behavior between study groups were illustrated by relating it to the visibility of a 12-15-month-old child-size object. These findings provide evidence that drivers adapt their glance behavior during low-speed parking maneuvers following extended use of rearview cameras and parking sensors, and suggest that other technologies which

  7. Perfecting the Photometric Calibration of the ACS CCD Cameras

    CERN Document Server

    Bohlin, Ralph C

    2016-01-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the CCD cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1\\% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC\\footnote{http://www.stsci.edu/hst/observatory/crds/calspec.html} database for three primary hot 30,000--60,000K WDs define the sensitivity calibrations for the WFC and HRC filters. The external uncertainty for the absolute flux is $\\sim$1\\%, while the internal consistency of the sensitivities in the broadband ACS filters is $\\sim$0.3\\% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1\\% at the WFC1-1K subarray position, which achieves the 1\\% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1\\% precision goal is achieved over the full ...

  8. Design of operation parameters of a high speed TDI CCD line scan camera

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper analyzes the operation parameters of the time delay and integration (TDI) line scan CCD camera, such as resolution, line rate, clock frequency, etc. and their mathematical relationship is deduced. By analyzing and calculating these parameters, the working clocks of the TDI CCD line scan camera are designed,which guarantees the synchronization of the line scan rate and the camera movement speed. The IL - E2 TDI CCD of DALSA Co. is used as the sensor of the camera in the paper. The working clock generator used for the TDI CCD sensor is realized by using the programmable logic device (PLD). The experimental results show that the working clock generator circuit satisfies the requirement of high speed TDI CCD line scan camera.

  9. A Large Area CCD Camera for the Schmidt Telescope at the Venezuelan National Astronomical Observatory

    CERN Document Server

    Baltay, C; Andrews, P; Emmet, W; Schaefer, B; Sinnott, J; Bailyn, C D; Coppi, P S; Oemler, A E; Sabbey, C N; Sofia, S; Van Altena, W F; Vivas, A K; Abad, C; Briceño, C; Bruzual, G; Magris, G; Stock, J; Prugna, F D; Sánchez, G; Schenner, H; Adams, B; Gebhard, M; Honeycutt, R K; Musser, J; Harris, F; Geary, J; Sanchez, Ge.; Sanchez, Gu.

    2002-01-01

    We have designed, constructed and put into operation a large area CCD camera that covers a large fraction of the image plane of the 1 meter Schmidt telescope at Llano del Hato in Venezuela. The camera consists of 16 CCD devices arranged in a 4 x 4 mosaic covering 2.3 degrees x 3.5 degrees of sky. The CCDs are 2048 x 2048 LORAL devices with 15 micron pixels. The camera is optimized for drift scan photometry and objective prism spectroscopy. The design considerations, construction features and performance parameters are described in the following article.

  10. Design of a very high frame rate camera based on an asynchronous CCD driving method

    Institute of Scientific and Technical Information of China (English)

    LI Bin-Kang; YANG Shao-Hua; GUO Ming-An; WANG gui-Lu; XIA Jing-Wao; LUO Tong-Ding

    2011-01-01

    A very high frame rate camera is designed based on an innovative CCD driving method. The CCD driving method is mainly implemented on frame transfer CCDs. Asynchronous drive timing sequences are applied in the image and storage section of the CCDs. Several rows of the charge in the image section are binned onto the same row in the storage section, and there are the same number of images to be stored in the storage section before they are read out. Based on the new driving method, the frame transfer CCDs can work at a very high frame rate in acquiring burst images though the reading speed remains at a lower level. A very high frame rate camera is designed in this paper. The innovative CCD driving method is mainly of concern. An e2v's CCD60 is adopted in the camera system, whose full size resolution is 128×128, and the up most frame rate is 1000 Hz in the conventional CCD driving method. By using the presented method, the CCD60 based imager is capable of operating at up to 40000 frames per second (fps) at a recognizable resolution of 128×32. Comparing cameras using traditional binning and region of interest technologies, the frame rate is normally less than 5000 fps while the resolution is only 32 × 32 lett.

  11. Radiation damage of the PCO Pixelfly VGA CCD camera of the BES system on KSTAR tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Náfrádi, Gábor, E-mail: nafradi@reak.bme.hu [NTI, BME, EURATOM Association, H-1111 Budapest (Hungary); Kovácsik, Ákos, E-mail: kovacsik.akos@reak.bme.hu [NTI, BME, EURATOM Association, H-1111 Budapest (Hungary); Pór, Gábor, E-mail: por@reak.bme.hu [NTI, BME, EURATOM Association, H-1111 Budapest (Hungary); Lampert, Máté, E-mail: lampert.mate@wigner.mta.hu [Wigner RCP, RMI, EURATOM Association, POB 49, 1525 Budapest (Hungary); Un Nam, Yong, E-mail: yunam@nfri.re.kr [NFRI, 169-148 Gwahak-Ro, Yuseong-Gu, Daejeon 305-806 (Korea, Republic of); Zoletnik, Sándor, E-mail: zoletnik.sandor@wigner.mta.hu [Wigner RCP, RMI, EURATOM Association, POB 49, 1525 Budapest (Hungary)

    2015-01-11

    A PCO Pixelfly VGA CCD camera which is part a of the Beam Emission Spectroscopy (BES) diagnostic system of the Korea Superconducting Tokamak Advanced Research (KSTAR) used for spatial calibrations, suffered from serious radiation damage, white pixel defects have been generated in it. The main goal of this work was to identify the origin of the radiation damage and to give solutions to avoid it. Monte Carlo N-Particle eXtended (MCNPX) model was built using Monte Carlo Modeling Interface Program (MCAM) and calculations were carried out to predict the neutron and gamma-ray fields in the camera position. Besides the MCNPX calculations pure gamma-ray irradiations of the CCD camera were carried out in the Training Reactor of BME. Before, during and after the irradiations numerous frames were taken with the camera with 5 s long exposure times. The evaluation of these frames showed that with the applied high gamma-ray dose (1.7 Gy) and dose rate levels (up to 2 Gy/h) the number of the white pixels did not increase. We have found that the origin of the white pixel generation was the neutron-induced thermal hopping of the electrons which means that in the future only neutron shielding is necessary around the CCD camera. Another solution could be to replace the CCD camera with a more radiation tolerant one for example with a suitable CMOS camera or apply both solutions simultaneously.

  12. Radiation damage of the PCO Pixelfly VGA CCD camera of the BES system on KSTAR tokamak

    Science.gov (United States)

    Náfrádi, Gábor; Kovácsik, Ákos; Pór, Gábor; Lampert, Máté; Un Nam, Yong; Zoletnik, Sándor

    2015-01-01

    A PCO Pixelfly VGA CCD camera which is part a of the Beam Emission Spectroscopy (BES) diagnostic system of the Korea Superconducting Tokamak Advanced Research (KSTAR) used for spatial calibrations, suffered from serious radiation damage, white pixel defects have been generated in it. The main goal of this work was to identify the origin of the radiation damage and to give solutions to avoid it. Monte Carlo N-Particle eXtended (MCNPX) model was built using Monte Carlo Modeling Interface Program (MCAM) and calculations were carried out to predict the neutron and gamma-ray fields in the camera position. Besides the MCNPX calculations pure gamma-ray irradiations of the CCD camera were carried out in the Training Reactor of BME. Before, during and after the irradiations numerous frames were taken with the camera with 5 s long exposure times. The evaluation of these frames showed that with the applied high gamma-ray dose (1.7 Gy) and dose rate levels (up to 2 Gy/h) the number of the white pixels did not increase. We have found that the origin of the white pixel generation was the neutron-induced thermal hopping of the electrons which means that in the future only neutron shielding is necessary around the CCD camera. Another solution could be to replace the CCD camera with a more radiation tolerant one for example with a suitable CMOS camera or apply both solutions simultaneously.

  13. High performance CCD camera system for digitalisation of 2D DIGE gels.

    Science.gov (United States)

    Strijkstra, Annemieke; Trautwein, Kathleen; Roesler, Stefan; Feenders, Christoph; Danzer, Daniel; Riemenschneider, Udo; Blasius, Bernd; Rabus, Ralf

    2016-07-01

    An essential step in 2D DIGE-based analysis of differential proteome profiles is the accurate and sensitive digitalisation of 2D DIGE gels. The performance progress of commercially available charge-coupled device (CCD) camera-based systems combined with light emitting diodes (LED) opens up a new possibility for this type of digitalisation. Here, we assessed the performance of a CCD camera system (Intas Advanced 2D Imager) as alternative to a traditionally employed, high-end laser scanner system (Typhoon 9400) for digitalisation of differential protein profiles from three different environmental bacteria. Overall, the performance of the CCD camera system was comparable to the laser scanner, as evident from very similar protein abundance changes (irrespective of spot position and volume), as well as from linear range and limit of detection.

  14. Theodolite with CCD Camera for Safe Measurement of Laser-Beam Pointing

    Science.gov (United States)

    Crooke, Julie A.

    2003-01-01

    The simple addition of a charge-coupled-device (CCD) camera to a theodolite makes it safe to measure the pointing direction of a laser beam. The present state of the art requires this to be a custom addition because theodolites are manufactured without CCD cameras as standard or even optional equipment. A theodolite is an alignment telescope equipped with mechanisms to measure the azimuth and elevation angles to the sub-arcsecond level. When measuring the angular pointing direction of a Class ll laser with a theodolite, one could place a calculated amount of neutral density (ND) filters in front of the theodolite s telescope. One could then safely view and measure the laser s boresight looking through the theodolite s telescope without great risk to one s eyes. This method for a Class ll visible wavelength laser is not acceptable to even consider tempting for a Class IV laser and not applicable for an infrared (IR) laser. If one chooses insufficient attenuation or forgets to use the filters, then looking at the laser beam through the theodolite could cause instant blindness. The CCD camera is already commercially available. It is a small, inexpensive, blackand- white CCD circuit-board-level camera. An interface adaptor was designed and fabricated to mount the camera onto the eyepiece of the specific theodolite s viewing telescope. Other equipment needed for operation of the camera are power supplies, cables, and a black-and-white television monitor. The picture displayed on the monitor is equivalent to what one would see when looking directly through the theodolite. Again, the additional advantage afforded by a cheap black-and-white CCD camera is that it is sensitive to infrared as well as to visible light. Hence, one can use the camera coupled to a theodolite to measure the pointing of an infrared as well as a visible laser.

  15. Atmospheric radiation environment analyses based-on CCD camera at various mountain altitudes and underground sites

    Directory of Open Access Journals (Sweden)

    Li Cavoli Pierre

    2016-01-01

    Full Text Available The purpose of this paper is to discriminate secondary atmospheric particles and identify muons by measuring the natural radiative environment in atmospheric and underground locations. A CCD camera has been used as a cosmic ray sensor. The Low Noise Underground Laboratory of Rustrel (LSBB, France gives the access to a unique low-noise scientific environment deep enough to ensure the screening from the neutron and proton radiative components. Analyses of the charge levels in pixels of the CCD camera induced by radiation events and cartographies of the charge events versus the hit pixel are proposed.

  16. Volumetric Diffuse Optical Tomography for Small Animals Using a CCD-Camera-Based Imaging System

    Directory of Open Access Journals (Sweden)

    Zi-Jing Lin

    2012-01-01

    Full Text Available We report the feasibility of three-dimensional (3D volumetric diffuse optical tomography for small animal imaging by using a CCD-camera-based imaging system with a newly developed depth compensation algorithm (DCA. Our computer simulations and laboratory phantom studies have demonstrated that the combination of a CCD camera and DCA can significantly improve the accuracy in depth localization and lead to reconstruction of 3D volumetric images. This approach may present great interests for noninvasive 3D localization of an anomaly hidden in tissue, such as a tumor or a stroke lesion, for preclinical small animal models.

  17. Perfecting the Photometric Calibration of the ACS CCD Cameras

    Science.gov (United States)

    Bohlin, Ralph C.

    2016-09-01

    Newly acquired data and improved data reduction algorithms mandate a fresh look at the absolute flux calibration of the charge-coupled device cameras on the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The goals are to achieve a 1% accuracy and to make this calibration more accessible to the HST guest investigator. Absolute fluxes from the CALSPEC1 database for three primary hot 30,000-60,000K WDs define the sensitivity calibrations for the Wide Field Channel (WFC) and High Resolution Channel (HRC) filters. The external uncertainty for the absolute flux is ˜1%, while the internal consistency of the sensitivities in the broadband ACS filters is ˜0.3% among the three primary WD flux standards. For stars as cool as K type, the agreement with the CALSPEC standards is within 1% at the WFC1-1K subarray position, which achieves the 1% precision goal for the first time. After making a small adjustment to the filter bandpass for F814W, the 1% precision goal is achieved over the full F814W WFC field of view for stars of K type and hotter. New encircled energies and absolute sensitivities replace the seminal results of Sirianni et al. that were published in 2005. After implementing the throughput updates, synthetic predictions of the WFC and HRC count rates for the average of the three primary WD standard stars agree with the observations to 0.1%.

  18. Time-resolved spectra of dense plasma focus using spectrometer, streak camera, and CCD combination

    Energy Technology Data Exchange (ETDEWEB)

    Goldin, F. J. [Livermore Operations, National Security Technologies, LLC, Livermore, California 94550 (United States); Meehan, B. T.; Hagen, E. C. [North Las Vegas Facility, National Security Technologies, LLC, North Las Vegas, Nevada 89030 (United States); Wilkins, P. R. [Lawrence Livermore National Laboratories, Livermore, California 94550 (United States)

    2010-10-15

    A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny-Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.

  19. Time-Resolved Spectra of Dense Plasma Focus Using Spectrometer, Streak Camera, CCD Combination

    Energy Technology Data Exchange (ETDEWEB)

    F. J. Goldin, B. T. Meehan, E. C. Hagen, P. R. Wilkins

    2010-10-01

    A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny–Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.

  20. BroCam: a versatile PC-based CCD camera system

    Science.gov (United States)

    Klougart, Jens

    1995-03-01

    At the Copenhagen University, we have developed a compact CCD camera system for single and mosaic CCDs. The camera control and data acquisition is performed by a 486 type PC via a frame buffer located in one ISA-bus slot, communicating to the camera electronics on two optical fibers. The PC can run as well special purpose DOS programs, as in a more general mode under LINUX, a UNIX similar operating system. In the latter mode, standard software packages, such as SAOimage and Gnuplot, are utilized extensively thereby reducing the amount of camera specific software. At the same time the observer feels at ease with the system in an IRAF-like environment. Finally, the LINUX version enables the camera to be remotely controlled.

  1. White light single-shot interferometry with colour CCD camera for optical inspection of microsystems

    Science.gov (United States)

    Upputuri, Paul Kumar; Pramanik, Manojit; Nandigana, Krishna Mohan; Kothiyal, Mahendra Prasad

    2015-07-01

    White light interferometry is a well-established optical tool for surface metrology of reflective samples. In this work, we discuss a single-shot white light interferometer based on single-chip color CCD camera and Hilbert transformation. The approach makes the measurement dynamic, faster, easier and cost-effective for industrial applications. Here we acquire only one white light interferogram using colour CCD camera and then decompose into its individual components using software. We present a simple Hilbert transformation approach to remove the non-uniform bias associated with the interference signal. The phases at individual wavelengths are calculated using Hilbert transformation. The use of Hilbert transformation introduces phase error which depends on number of fringe cycles. We discuss these errors. Experimental results on reflective micro-scale-samples for surface profiling are presented.

  2. Measuring high-resolution sky luminance distributions with a CCD camera.

    Science.gov (United States)

    Tohsing, Korntip; Schrempf, Michael; Riechelmann, Stefan; Schilke, Holger; Seckmeyer, Gunther

    2013-03-10

    We describe how sky luminance can be derived from a newly developed hemispherical sky imager (HSI) system. The system contains a commercial compact charge coupled device (CCD) camera equipped with a fish-eye lens. The projection of the camera system has been found to be nearly equidistant. The luminance from the high dynamic range images has been calculated and then validated with luminance data measured by a CCD array spectroradiometer. The deviation between both datasets is less than 10% for cloudless and completely overcast skies, and differs by no more than 20% for all sky conditions. The global illuminance derived from the HSI pictures deviates by less than 5% and 20% under cloudless and cloudy skies for solar zenith angles less than 80°, respectively. This system is therefore capable of measuring sky luminance with the high spatial and temporal resolution of more than a million pixels and every 20 s respectively.

  3. Measurements of surface roughness: use of a CCD camera to correlate doubly scattered speckle patterns

    Science.gov (United States)

    Basano, Lorenzo; Leporatti, Stefano; Ottonello, Pasquale; Palestini, Valeria; Rolandi, Ranieri

    1995-11-01

    We describe an instrument, built around a commercial CCD camera and some fast image-processing boards, that evaluates roughness height by measuring the average size of doubly scattered speckle patterns. The device is a variant of a recent proposal that was based on the use of a spatial modulator to perform the Fourier transform of a speckle image. In the present setup, the Fourier transform is replaced by the direct evaluation of a second-order correlation function. Strictly speaking, the device proposed in this paper is not a real-time device but its response time (approximately 10 s) is sufficiently short to be of practical value for many applications. Updated CCD cameras that will significantly improve the performance of our prototype are already on the market.

  4. High-resolution image digitizing through 12x3-bit RGB-filtered CCD camera

    Science.gov (United States)

    Cheng, Andrew Y. S.; Pau, Michael C. Y.

    1996-09-01

    A high resolution computer-controlled CCD image capturing system is developed by using a 12 bits 1024 by 1024 pixels CCD camera and motorized RGB filters to grasp an image with color depth up to 36 bits. The filters distinguish the major components of color and collect them separately while the CCD camera maintains the spatial resolution and detector filling factor. The color separation can be done optically rather than electronically. The operation is simply by placing the capturing objects like color photos, slides and even x-ray transparencies under the camera system, the necessary parameters such as integration time, mixing level and light intensity are automatically adjusted by an on-line expert system. This greatly reduces the restrictions of the capturing species. This unique approach can save considerable time for adjusting the quality of image, give much more flexibility of manipulating captured object even if it is a 3D object with minimal setup fixers. In addition, cross sectional dimension of a 3D capturing object can be analyzed by adapting a fiber optic ring light source. It is particularly useful in non-contact metrology of a 3D structure. The digitized information can be stored in an easily transferable format. Users can also perform a special LUT mapping automatically or manually. Applications of the system include medical images archiving, printing quality control, 3D machine vision, and etc.

  5. On-Line High Dose-Rate Gamma Ray Irradiation Test of the CCD/CMOS Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    In this paper, test results of gamma ray irradiation to CCD/CMOS cameras are described. From the CAMS (containment atmospheric monitoring system) data of Fukushima Dai-ichi nuclear power plant station, we found out that the gamma ray dose-rate when the hydrogen explosion occurred in nuclear reactors 1{approx}3 is about 160 Gy/h. If assumed that the emergency response robot for the management of severe accident of the nuclear power plant has been sent into the reactor area to grasp the inside situation of reactor building and to take precautionary measures against releasing radioactive materials, the CCD/CMOS cameras, which are loaded with the robot, serve as eye of the emergency response robot. In the case of the Japanese Quince robot system, which was sent to carry out investigating the unit 2 reactor building refueling floor situation, 7 CCD/CMOS cameras are used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. In the preceding assumptions, a major problem which arises when dealing with CCD/CMOS cameras in the severe accident situations of the nuclear power plant is the presence of high dose-rate gamma irradiation fields. In the case of the DBA (design basis accident) situations of the nuclear power plant, in order to use a CCD/CMOS camera as an ad-hoc monitoring unit in the vicinity of high radioactivity structures and components of the nuclear reactor area, a robust survivability of this camera in such intense gamma-radiation fields therefore should be verified. The CCD/CMOS cameras of various types were gamma irradiated at a

  6. Data acquisition system based on the Nios II for a CCD camera

    Science.gov (United States)

    Li, Binhua; Hu, Keliang; Wang, Chunrong; Liu, Yangbing; He, Chun

    2006-06-01

    The FPGA with Avalon Bus architecture and Nios soft-core processor developed by Altera Corporation is an advanced embedded solution for control and interface systems. A CCD data acquisition system with an Ethernet terminal port based on the TCP/IP protocol is implemented in NAOC, which is composed of a piece of interface board with an Altera's FPGA, 32MB SDRAM and some other accessory devices integrated on it, and two packages of control software used in the Nios II embedded processor and the remote host PC respectively. The system is used to replace a 7200 series image acquisition card which is inserted in a control and data acquisition PC, and to download commands to an existing CCD camera and collect image data from the camera to the PC. The embedded chip in the system is a Cyclone FPGA with a configurable Nios II soft-core processor. Hardware structure of the system, configuration for the embedded soft-core processor, and peripherals of the processor in the PFGA are described. The C program run in the Nios II embedded system is built in the Nios II IDE kits and the C++ program used in the PC is developed in the Microsoft's Visual C++ environment. Some key techniques in design and implementation of the C and VC++ programs are presented, including the downloading of the camera commands, initialization of the camera, DMA control, TCP/IP communication and UDP data uploading.

  7. Numerical simulations and analyses of temperature control loop heat pipe for space CCD camera

    Science.gov (United States)

    Meng, Qingliang; Yang, Tao; Li, Chunlin

    2016-10-01

    As one of the key units of space CCD camera, the temperature range and stability of CCD components affect the image's indexes. Reasonable thermal design and robust thermal control devices are needed. One kind of temperature control loop heat pipe (TCLHP) is designed, which highly meets the thermal control requirements of CCD components. In order to study the dynamic behaviors of heat and mass transfer of TCLHP, particularly in the orbital flight case, a transient numerical model is developed by using the well-established empirical correlations for flow models within three dimensional thermal modeling. The temperature control principle and details of mathematical model are presented. The model is used to study operating state, flow and heat characteristics based upon the analyses of variations of temperature, pressure and quality under different operating modes and external heat flux variations. The results indicate that TCLHP can satisfy the thermal control requirements of CCD components well, and always ensure good temperature stability and uniformity. By comparison between flight data and simulated results, it is found that the model is to be accurate to within 1°C. The model can be better used for predicting and understanding the transient performance of TCLHP.

  8. Non-Metric CCD Camera Calibration Algorithm in a Digital Photogrammetry System

    Institute of Scientific and Technical Information of China (English)

    YANG Hua-chao; DENG Ka-zhong; ZHANG Shu-bi; GUO Guang-li; ZHOU Ming

    2006-01-01

    Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation (DLT) and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectively, which can meet the requirements of close-range photogrammetry with high accuracy.

  9. Optical characterization of the SOFIA telescope using fast EM-CCD cameras

    Science.gov (United States)

    Pfüller, Enrico; Wolf, Jürgen; Hall, Helen; Röser, Hans-Peter

    2012-09-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) has recently demonstrated its scientific capabilities in a first series of astronomical observing flights. In parallel, special measurements and engineering flights were conducted aiming at the characterization and the commissioning of the telescope and the complete airborne observatory. To support the characterization measurements, two commercial Andor iXon EM-CCD cameras have been used, a DU-888 dubbed Fast Diagnostic Camera (FDC) running at frame rates up to about 400 fps, and a DU-860 as a Super Fast Diagnostic Camera (SFDC) providing 2000 fps. Both cameras have been mounted to the telescope’s Focal Plane Imager (FPI) flange in lieu of the standard FPI tracking camera. Their fast image sequences have been used to analyze and to improve the telescope’s pointing stability, especially to help tuning active mass dampers that suppress eigenfrequencies in the telescope system, to characterize and to optimize the chopping secondary mirror and to investigate the structure and behavior of the shear layer that forms over the open telescope cavity in flight. In June 2011, a collaboration between the HIPO science instrument team, the MIT’s stellar occultation group and the FDC team, led to the first SOFIA observation of a stellar occultation by the dwarf planet Pluto over the Pacific.

  10. A rehabilitation training system with double-CCD camera and automatic spatial positioning technique

    Science.gov (United States)

    Lin, Chern-Sheng; Wei, Tzu-Chi; Lu, An-Tsung; Hung, San-Shan; Chen, Wei-Lung; Chang, Chia-Chang

    2011-03-01

    This study aimed to develop a computer game for machine vision integrated rehabilitation training system. The main function of the system is to allow users to conduct hand grasp-and-place movement through machine vision integration. Images are captured by a double-CCD camera, and then positioned on a large screen. After defining the right, left, upper, and lower boundaries of the captured images, an automatic spatial positioning technique is employed to obtain their correlation functions, and lookup tables are defined for cameras. This system can provide rehabilitation courses and games that allow users to exercise grasp-and-place movements, in order to improve their upper limb movement control, trigger trunk control, and balance training.

  11. Development of the analog ASIC for multi-channel readout X-ray CCD camera

    CERN Document Server

    Nakajima, Hiroshi; Idehara, Toshihiro; Anabuki, Naohisa; Tsunemi, Hiroshi; Doty, John P; Ikeda, Hirokazu; Katayama, Haruyoshi; Kitamura, Hisashi; Uchihori, Yukio; 10.1016/j.nima.2010.12.174

    2011-01-01

    We report on the performance of an analog application-specific integrated circuit (ASIC) developed aiming for the front-end electronics of the X-ray CCDcamera system onboard the next X-ray astronomical satellite, ASTRO-H. It has four identical channels that simultaneously process the CCD signals. Distinctive capability of analog-to-digital conversion enables us to construct a CCD camera body that outputs only digital signals. As the result of the front-end electronics test, it works properly with low input noise of =<30 uV at the pixel rate below 100 kHz. The power consumption is sufficiently low of about 150 mW/chip. The input signal range of 720 mV covers the effective energy range of the typical X-ray photon counting CCD (up to 20 keV). The integrated non-linearity is 0.2% that is similar as those of the conventional CCDs in orbit. We also performed a radiation tolerance test against the total ionizing dose (TID) effect and the single event effect. The irradiation test using 60Co and proton beam showed ...

  12. Measuring neutron fluences and gamma/x ray fluxes with CCD cameras

    Science.gov (United States)

    Yates, G. J.; Smith, G. W.; Zagarino, P.; Thomas, M. C.

    The capability to measure bursts of neutron fluences and gamma/x-ray fluxes directly with charge coupled device (CCD) cameras while being able to distinguish between the video signals produced by these two types of radiation, even when they occur simultaneously, has been demonstrated. Volume and area measurements of transient radiation-induced pixel charge in English Electric Valve (EEV) Frame Transfer (FT) charge coupled devices (CCD's) from irradiation with pulsed neutrons (14 MeV) and Bremsstrahlung photons (4-12 MeV endpoint) are utilized to calibrate the devices as radiometric imaging sensors capable of distinguishing between the two types of ionizing radiation. Measurements indicate approx. = .05 V/rad responsivity with greater than or = 1 rad required for saturation from photon irradiation. Neutron-generated localized charge centers or 'peaks' binned by area and amplitude as functions of fluence in the 105 to 107 n/cc range indicate smearing over approx. 1 to 10 percent of the CCD array with charge per pixel ranging between noise and saturation levels.

  13. A high-sensitivity EM-CCD camera for the open port telescope cavity of SOFIA

    Science.gov (United States)

    Wiedemann, Manuel; Wolf, Jürgen; McGrotty, Paul; Edwards, Chris; Krabbe, Alfred

    2016-08-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) has three target acquisition and tracking cameras. All three imagers originally used the same cameras, which did not meet the sensitivity requirements, due to low quantum efficiency and high dark current. The Focal Plane Imager (FPI) suffered the most from high dark current, since it operated in the aircraft cabin at room temperatures without active cooling. In early 2013 the FPI was upgraded with an iXon3 888 from Andor Techonolgy. Compared to the original cameras, the iXon3 has a factor five higher QE, thanks to its back-illuminated sensor, and orders of magnitude lower dark current, due to a thermo-electric cooler and "inverted mode operation." This leads to an increase in sensitivity of about five stellar magnitudes. The Wide Field Imager (WFI) and Fine Field Imager (FFI) shall now be upgraded with equally sensitive cameras. However, they are exposed to stratospheric conditions in flight (typical conditions: T≍-40° C, p≍ 0:1 atm) and there are no off-the-shelf CCD cameras with the performance of an iXon3, suited for these conditions. Therefore, Andor Technology and the Deutsches SOFIA Institut (DSI) are jointly developing and qualifying a camera for these conditions, based on the iXon3 888. These changes include replacement of electrical components with MIL-SPEC or industrial grade components and various system optimizations, a new data interface that allows the image data transmission over 30m of cable from the camera to the controller, a new power converter in the camera to generate all necessary operating voltages of the camera locally and a new housing that fulfills airworthiness requirements. A prototype of this camera has been built and tested in an environmental test chamber at temperatures down to T=-62° C and pressure equivalent to 50 000 ft altitude. In this paper, we will report about the development of the camera and present results from the environmental testing.

  14. STRIPING NOISE REMOVAL OF IMAGES ACQUIRED BY CBERS 2 CCD CAMERA SENSOR

    Directory of Open Access Journals (Sweden)

    E. Amraei

    2014-10-01

    Full Text Available CCD Camera is a multi-spectral sensor that is carried by CBERS 2 satellite. Imaging technique in this sensor is push broom. In images acquired by the CCD Camera, some vertical striping noise can be seen. This is due to the detectors mismatch, inter detector variability, improper calibration of detectors and low signal-to-noise ratio. These noises are more profound in images acquired from the homogeneous surfaces, which are processed at level 2. However, the existence of these noises render the interpretation of the data and extracting information from these images difficult. In this work, spatial moment matching method is proposed to modify these images. In this method, the statistical moments such as mean and standard deviation of columns in each band are used to balance the statistical specifications of the detector array to those of reference values. After the removal of the noise, some periodic diagonal stripes remain in the image where their removal by using the aforementioned method seems impossible. Therefore, to omit them, frequency domain Butterworth notch filter was applied. Finally to evaluate the results, the image statistical moments such as the mean and standard deviation were deployed. The study proves the effectiveness of the method in noise removal.

  15. Front- vs. back-illuminated CCD cameras for photometric surveys: a noise budget analysis

    CERN Document Server

    Crouzet, Nicolas; Fressin, Francois; Blazit, Alain

    2008-01-01

    Exoplanetary transit and stellar oscillation surveys require a very high precision photometry. The instrumental noise has therefore to be minimized. First, we perform a semi-analytical model of different noise sources. We show that the noise due the CCD electrodes can be overcome using a Gaussian PSF (Point Spread Function) of full width half maximum larger than 1.6 pixels. We also find that for a PSF size of a few pixels, the photometric aperture has to be at least 2.5 times larger than the PSF full width half maximum. Then, we compare a front- with a back-illuminated CCD through a Monte-Carlo simulation. Both cameras give the same results for a PSF full width half maximum larger than 1.5 pixels. All these simulations are applied to the A STEP (Antarctica Search for Transiting Extrasolar Planets) project. As a result, we choose a front-illuminated camera for A STEP because of its better resolution and lower price, and we will use a PSF larger than 1.6 pixels.

  16. A toolkit for the characterization of CCD cameras for transmission electron microscopy.

    Science.gov (United States)

    Vulovic, M; Rieger, B; van Vliet, L J; Koster, A J; Ravelli, R B G

    2010-01-01

    Charge-coupled devices (CCD) are nowadays commonly utilized in transmission electron microscopy (TEM) for applications in life sciences. Direct access to digitized images has revolutionized the use of electron microscopy, sparking developments such as automated collection of tomographic data, focal series, random conical tilt pairs and ultralarge single-particle data sets. Nevertheless, for ultrahigh-resolution work photographic plates are often still preferred. In the ideal case, the quality of the recorded image of a vitrified biological sample would solely be determined by the counting statistics of the limited electron dose the sample can withstand before beam-induced alterations dominate. Unfortunately, the image is degraded by the non-ideal point-spread function of the detector, as a result of a scintillator coupled by fibre optics to a CCD, and the addition of several inherent noise components. Different detector manufacturers provide different types of figures of merit when advertising the quality of their detector. It is hard for most laboratories to verify whether all of the anticipated specifications are met. In this report, a set of algorithms is presented to characterize on-axis slow-scan large-area CCD-based TEM detectors. These tools have been added to a publicly available image-processing toolbox for MATLAB. Three in-house CCD cameras were carefully characterized, yielding, among others, statistics for hot and bad pixels, the modulation transfer function, the conversion factor, the effective gain and the detective quantum efficiency. These statistics will aid data-collection strategy programs and provide prior information for quantitative imaging. The relative performance of the characterized detectors is discussed and a comparison is made with similar detectors that are used in the field of X-ray crystallography.

  17. Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

    Science.gov (United States)

    Joiner, Reyann; Kobayashi, Ken; Winebarger, Amy; Champey, Patrick

    2014-01-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding rocket instrument currently being developed by NASA's Marshall Space Flight Center (MSFC), the National Astronomical Observatory of Japan (NAOJ), and other partners. The goal of this instrument is to observe and detect the Hanle effect in the scattered Lyman-Alpha UV (121.6nm) light emitted by the Sun's chromosphere. The polarized spectrum imaged by the CCD cameras will capture information about the local magnetic field, allowing for measurements of magnetic strength and structure. In order to make accurate measurements of this effect, the performance characteristics of the three on- board charge-coupled devices (CCDs) must meet certain requirements. These characteristics include: quantum efficiency, gain, dark current, read noise, and linearity. Each of these must meet predetermined requirements in order to achieve satisfactory performance for the mission. The cameras must be able to operate with a gain of 2.0+/- 0.5 e--/DN, a read noise level less than 25e-, a dark current level which is less than 10e-/pixel/s, and a residual non- linearity of less than 1%. Determining these characteristics involves performing a series of tests with each of the cameras in a high vacuum environment. Here we present the methods and results of each of these performance tests for the CLASP flight cameras.

  18. Performance of the low light level CCD camera for speckle imaging

    CERN Document Server

    Saha, S K

    2002-01-01

    A new generation CCD detector called low light level CCD (L3CCD) that performs like an intensified CCD without incorporating a micro channel plate (MCP) for light amplification was procured and tested. A series of short exposure images with millisecond integration time has been obtained. The L3CCD is cooled to about $-80^\\circ$ C by Peltier cooling.

  19. High time resolution CCD camera with X-ray image intensifier for SPring-8 BL40XU

    CERN Document Server

    Oka, T; Yagi, N

    2003-01-01

    SPring-8 BL40XU is designed to use high flux X-ray for small angle X-ray scattering and multi purpose. The flux at the experimental hutch is about 1 x 10 sup 1 sup 5 photons/sec at 12.4 KeV, which is larger 2 approx 3 figures than other beamlines at SPring-8. To utilize the high flux X-ray efficiently, new high-speed detector is needed. Therefore, a high frame rate CCD camera C7770 (Hamamatsu) and a new 6-inch X-ray image intensifier V5445P (Hamamatsu) were developed for BL40XU. The CCD camera has three CCD chips to increase the readout speed. Three identical images are created by a prism system in the CCD camera and projected onto the three chips. The pixel number of the CCD is 640 x 480 and the frame rate is 291 frames/sec. Reduction of the number of horizontal lines leads to a faster frame rate up to a few thousands. The combination of the CCD and with an X-ray shutter also leads to faster discrete data acquisition. (author)

  20. CTK-II & RTK: The CCD-cameras operated at the auxiliary telescopes of the University Observatory Jena

    Science.gov (United States)

    Mugrauer, M.

    2016-03-01

    The Cassegrain-Teleskop-Kamera (CTK-II) and the Refraktor-Teleskop-Kamera (RTK) are two CCD-imagers which are operated at the 25 cm Cassegrain and 20 cm refractor auxiliary telescopes of the University Observatory Jena. This article describes the main characteristics of these instruments. The properties of the CCD-detectors, the astrometry, the image quality, and the detection limits of both CCD-cameras, as well as some results of ongoing observing projects, carried out with these instruments, are presented. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.

  1. Characterization of a commercial, front-illuminated interline transfer CCD camera for use as a guide camera on a balloon-borne telescope

    CERN Document Server

    Clark, Paul; Chang, Herrick L; Galloway, Mathew; Israel, Holger; Jones, Laura L; Li, Lun; Mandic, Milan; Morris, Tim; Netterfield, Barth; Peacock, John; Sharples, Ray; Susca, Sara

    2014-01-01

    We report results obtained during the characterization of a commercial front-illuminated progressive scan interline transfer CCD camera. We demonstrate that the unmodified camera operates successfully in temperature and pressure conditions (-40C, 4mBar) representative of a high altitude balloon mission. We further demonstrate that the centroid of a well-sampled star can be determined to better than 2% of a pixel, even though the CCD is equipped with a microlens array. This device has been selected for use in a closed-loop star-guiding and tip-tilt correction system in the BIT-STABLE balloon mission.

  2. Development of X-ray CCD camera based X-ray micro-CT system.

    Science.gov (United States)

    Sarkar, Partha S; Ray, N K; Pal, Manoj K; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y; Sinha, A; Gadkari, S C

    2017-02-01

    Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

  3. Auto-measuring system of aero-camera lens focus using linear CCD

    Science.gov (United States)

    Zhang, Yu-ye; Zhao, Yu-liang; Wang, Shu-juan

    2014-09-01

    The automatic and accurate focal length measurement of aviation camera lens is of great significance and practical value. The traditional measurement method depends on the human eye to read the scribed line on the focal plane of parallel light pipe by means of reading microscope. The method is of low efficiency and the measuring results are influenced by artificial factors easily. Our method used linear array solid-state image sensor instead of reading microscope to transfer the imaging size of specific object to be electrical signal pulse width, and used computer to measure the focal length automatically. In the process of measurement, the lens to be tested placed in front of the object lens of parallel light tube. A couple of scribed line on the surface of the parallel light pipe's focal plane were imaging on the focal plane of the lens to be tested. Placed the linear CCD drive circuit on the image plane, the linear CCD can convert the light intensity distribution of one dimension signal into time series of electrical signals. After converting, a path of electrical signals is directly brought to the video monitor by image acquisition card for optical path adjustment and focusing. The other path of electrical signals is processed to obtain the pulse width corresponding to the scribed line by electrical circuit. The computer processed the pulse width and output focal length measurement result. Practical measurement results showed that the relative error was about 0.10%, which was in good agreement with the theory.

  4. Applications in radiation therapy of a scintillating screen viewed by a CCD camera

    CERN Document Server

    Schippers, J M; Luijk, P V

    2002-01-01

    A two-dimensional (2D) dosimetry system has been designed for position-sensitive dose-measurement applications in modern radiation therapy. The system consists of a scintillating screen (Gd sub 2 O sub 2 S : Tb), observed by a low-noise CCD camera with a long integration time. The system allows reliable and accurate simultaneous 2D imaging of therapeutic dose distributions in the scintillator with sub millimeter spatial resolution. This system has been applied successfully at different applications in radiation therapy. Results of dose measurements in a treatment modality using a scanning proton beam are reported. It is shown that a quick and reliable measurement can be done. The screen+CCD system has proven to perform accurate dosimetry in applications where beams with a small (1-5 mm) diameter are used and where absolute dosimetry by means of standard ionization chambers is not possible due to their relatively large size. For the routine measurements of the alignment of therapeutic beams with respect to the...

  5. Development of X-ray CCD camera based X-ray micro-CT system

    Science.gov (United States)

    Sarkar, Partha S.; Ray, N. K.; Pal, Manoj K.; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y.; Sinha, A.; Gadkari, S. C.

    2017-02-01

    Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

  6. ULTRACAM: an ultra-fast, triple-beam CCD camera for high-speed astrophysics

    CERN Document Server

    Dhillon, V S; Stevenson, M J; Atkinson, D C; Kerry, P; Peacocke, P T; Vick, A J A; Beard, S M; Ives, D J; Lunney, D W; McLay, S A; Tierney, C J; Kelly, J; Littlefair, S P; Nicholson, R; Pashley, R; Harlaftis, E T; O'Brien, K

    2007-01-01

    ULTRACAM is a portable, high-speed imaging photometer designed to study faint astronomical objects at high temporal resolutions. ULTRACAM employs two dichroic beamsplitters and three frame-transfer CCD cameras to provide three-colour optical imaging at frame rates of up to 500 Hz. The instrument has been mounted on both the 4.2-m William Herschel Telescope on La Palma and the 8.2-m Very Large Telescope in Chile, and has been used to study white dwarfs, brown dwarfs, pulsars, black-hole/neutron-star X-ray binaries, gamma-ray bursts, cataclysmic variables, eclipsing binary stars, extrasolar planets, flare stars, ultra-compact binaries, active galactic nuclei, asteroseismology and occultations by Solar System objects (Titan, Pluto and Kuiper Belt objects). In this paper we describe the scientific motivation behind ULTRACAM, present an outline of its design and report on its measured performance.

  7. Obstacle Avoidance Control for Mobile Robot Based on Single CCD Camera and Ultrasonic Sensors

    Science.gov (United States)

    Nara, Shunsuke; Takahashi, Satoru

    This paper proposes an available method of obstacle avoidance control by using a single CCD camera and ultrasonic sensors mounted on the mobile robot. First, depending on the change of the brightness on the image that occurs from the moving of the mobile robot, we calculate the optical flow by the block matching method based on the normalized correlation and detect the obstacle area on the image. Further, in order to reduce the error of the detection area, by combining the distance information obtained by ultrasonic sensors on the image shown the obstacle area we decide the position of obstacle with high accuracy. Dealing with the position information, we make the reference points for generating the trajectory of the mobile robot. This trajectory is smooth and is generated by minimizing a certain cost function. Then, the mobile robot moves according to the trajectory while avoiding around the obstacle. Finally, usefulness of our proposed method is shown through some experiments.

  8. Quantum efficiency of the CCD camera (XIS) for the ASTRO-E mission

    CERN Document Server

    Katayama, H; Kohmura, T; Katayama, K; Yoshita, K; Tsunemi, H; Kitamoto, S; Hayashida, K; Miyata, E; Hashimotodani, K; Koyama, K; Ricker, G; Bautz, M W; Foster, R; Kissel, S

    1999-01-01

    We measured the optical and the X-ray transmission of the optical blocking filters for the X-ray Imaging Spectrometers (XISs) which are the X-ray CCD cameras of the ASTRO-E satellite. We conclude that the oxidation of the aluminum reduces the optical transmission down to approx 60-70% of the theoretical value of the aluminum. We achieved optical transmission below 5x10 sup - sup 5 in the range from 4000 to 9500 A by using aluminum thickness of 1200 A, while the theoretical calculation requires 800 A. The measurement of absolute quantum efficiency of XIS is also performed at several particular energies. We confirmed 20% quantum efficiency at 0.5 keV for the XIS engineering model (XIS EM).

  9. Application of CCD Cameras to Investigations of Mixing on Boundaries of a Thermal Plasma Jet

    Institute of Scientific and Technical Information of China (English)

    J.HLINA; J.(S)ONSKY; J.(S)LECHTA

    2007-01-01

    Mixing of a thermal plasma jet with the surrounding atmosphere was studied using two CCD cameras (PCO SensiCam) situated detecting simultaneously the radiation of argon and nitrogen.The evaluation of image differences between two records showed that the location of regions on plasma jet boundaries characterised by stronger nitrogen radiation changes with the plasma flow rate.Close-to-laminar flow results in a small mixing rate and consequently low nitrogen optical emission on plasma jet boundaries.The increase of the flow rate leads to the formation of a relatively thick and stable layer on the boundaries characterised by strong nitrogen radiation.Further enhancement of the flow rate results in the formation of unstable regions of excited nitrogen molecules moving along the jet.

  10. Retrieval of the optical depth using an all-sky CCD camera.

    Science.gov (United States)

    Olmo, Francisco J; Cazorla, Alberto; Alados-Arboledas, Lucas; López-Alvarez, Miguel A; Hernández-Andrés, Javier; Romero, Javier

    2008-12-01

    A new method is presented for retrieval of the aerosol and cloud optical depth using a CCD camera equipped with a fish-eye lens (all-sky imager system). In a first step, the proposed method retrieves the spectral radiance from sky images acquired by the all-sky imager system using a linear pseudoinverse algorithm. Then, the aerosol or cloud optical depth at 500 nm is obtained as that which minimizes the residuals between the zenith spectral radiance retrieved from the sky images and that estimated by the radiative transfer code. The method is tested under extreme situations including the presence of nonspherical aerosol particles. The comparison of optical depths derived from the all-sky imager with those retrieved with a sunphotometer operated side by side shows differences similar to the nominal error claimed in the aerosol optical depth retrievals from sunphotometer networks.

  11. The high resolution gamma imager (HRGI): a CCD based camera for medical imaging

    Science.gov (United States)

    Lees, John. E.; Fraser, George. W.; Keay, Adam; Bassford, David; Ott, Robert; Ryder, William

    2003-11-01

    We describe the High Resolution Gamma Imager (HRGI): a Charge Coupled Device (CCD) based camera for imaging small volumes of radionuclide uptake in tissues. The HRGI is a collimated, scintillator-coated, low cost, high performance imager using low noise CCDs that will complement whole-body imaging Gamma Cameras in nuclear medicine. Using 59.5 keV radiation from a 241Am source we have measured the spatial resolution and relative efficiency of test CCDs from E2V Technologies (formerly EEV Ltd.) coated with Gadox (Gd 2O 2S(Tb)) layers of varying thicknesses. The spatial resolution degrades from 0.44 to 0.6 mm and the detection efficiency increases (×3) as the scintillator thickness increases from 100 to 500 μm. We also describe our first image using the clinically important isotope 99mTc. The final HRGI will have intrinsic sub-mm spatial resolution (˜0.7 mm) and good energy resolution over the energy range 30-160 keV.

  12. CCD digital camera system for measuring curvature and ovalization of each cross-section of circular tube under cyclic bending

    National Research Council Canada - National Science Library

    Lee, Kuo-Long; Hung, Chao-Yu; Pan, Wen-Fung

    2011-01-01

    .... To test the capability of this newly designed measurement system, a tube-bending machine was employed to test, experimentally, a 7005-T53 aluminum alloy tube under cyclic bending, and the CCD digital camera system was utilized to measure the curvature and each cross-sectional ovalization of the tube.

  13. STUDY ON THE LINE SCAN CCD CAMERA CALIBRATION OF VEHICLE-BORNE 3D DATA ACQUISITION SYSTEM

    OpenAIRE

    Han, Y; Yang, B.; F. Zhang

    2012-01-01

    Based on the characters of the line scan CCD camera and the Vehicle-borne 3D data acquisition system, it presented a novel method to calibrate the line Scan Camera (LSC) based on the laser scanner. Using the angle information in the original laser scanner data, combing the principle of the line scan camera, it built a calibration model for LSC and designed some experiment methods to implement that. Using the new model and the special experiment methods it computed out high precision ...

  14. Cooling the dark energy camera CCD array using a closed-loop two-phase liquid nitrogen system

    Science.gov (United States)

    Cease, H.; DePoy, D.; Derylo, G.; Diehl, H. T.; Estrada, J.; Flaugher, B.; Kuk, K.; Kuhlmann, S.; Lathrop, A.; Schultz, K.; Reinert, R. J.; Schmitt, R. L.; Stefanik, A.; Zhao, A.

    2010-07-01

    The Dark Energy Camera (DECam) is the new wide field prime-focus imager for the Blanco 4m telescope at CTIO. This instrument is a 3 sq. deg. camera with a 45 cm diameter focal plane consisting of 62 2k × 4k CCDs and 12 2k × 2k CCDs and was developed for the Dark Energy Survey that will start operations at CTIO in 2011. The DECam CCD array is inside the imager vessel. The focal plate is cooled using a closed loop liquid nitrogen system. As part of the development of the mechanical and cooling design, a full scale prototype imager vessel has been constructed and is now being used for Multi-CCD readout tests. The cryogenic cooling system and thermal controls are described along with cooling results from the prototype camera. The cooling system layout on the Blanco telescope in Chile is described.

  15. OP09O-OP404-9 Wide Field Camera 3 CCD Quantum Efficiency Hysteresis

    Science.gov (United States)

    Collins, Nick

    2009-01-01

    The HST/Wide Field Camera (WFC) 3 UV/visible channel CCD detectors have exhibited an unanticipated quantum efficiency hysteresis (QEH) behavior. At the nominal operating temperature of -83C, the QEH feature contrast was typically 0.1-0.2% or less. The behavior was replicated using flight spare detectors. A visible light flat-field (540nm) with a several times full-well signal level can pin the detectors at both optical (600nm) and near-UV (230nm) wavelengths, suppressing the QEH behavior. We are characterizing the timescale for the detectors to become unpinned and developing a protocol for flashing the WFC3 CCDs with the instrument's internal calibration system in flight. The HST/Wide Field Camera 3 UV/visible channel CCD detectors have exhibited an unanticipated quantum efficiency hysteresis (QEH) behavior. The first observed manifestation of QEH was the presence in a small percentage of flat-field images of a bowtie-shaped contrast that spanned the width of each chip. At the nominal operating temperature of -83C, the contrast observed for this feature was typically 0.1-0.2% or less, though at warmer temperatures contrasts up to 5% (at -50C) have been observed. The bowtie morphology was replicated using flight spare detectors in tests at the GSFC Detector Characterization Laboratory by power cycling the detector while cold. Continued investigation revealed that a clearly-related global QE suppression at the approximately 5% level can be produced by cooling the detector in the dark; subsequent flat-field exposures at a constant illumination show asymptotically increasing response. This QE "pinning" can be achieved with a single high signal flat-field or a series of lower signal flats; a visible light (500-580nm) flat-field with a signal level of several hundred thousand electrons per pixel is sufficient for QE pinning at both optical (600nm) and near-UV (230nm) wavelengths. We are characterizing the timescale for the detectors to become unpinned and developing a

  16. Measuring the Flatness of Focal Plane for Very Large Mosaic CCD Camera

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Jiangang; Estrada, Juan; Cease, Herman; Diehl, H.Thomas; Flaugher, Brenna L.; Kubik, Donna; Kuk, Keivin; Kuropatkine, Nickolai; Lin, Huan; Montes, Jorge; Scarpine, Vic; /Fermilab

    2010-06-08

    Large mosaic multiCCD camera is the key instrument for modern digital sky survey. DECam is an extremely red sensitive 520 Megapixel camera designed for the incoming Dark Energy Survey (DES). It is consist of sixty two 4k x 2k and twelve 2k x 2k 250-micron thick fully-depleted CCDs, with a focal plane of 44 cm in diameter and a field of view of 2.2 square degree. It will be attached to the Blanco 4-meter telescope at CTIO. The DES will cover 5000 square-degrees of the southern galactic cap in 5 color bands (g, r, i, z, Y) in 5 years starting from 2011. To achieve the science goal of constraining the Dark Energy evolution, stringent requirements are laid down for the design of DECam. Among them, the flatness of the focal plane needs to be controlled within a 60-micron envelope in order to achieve the specified PSF variation limit. It is very challenging to measure the flatness of the focal plane to such precision when it is placed in a high vacuum dewar at 173 K. We developed two image based techniques to measure the flatness of the focal plane. By imaging a regular grid of dots on the focal plane, the CCD offset along the optical axis is converted to the variation the grid spacings at different positions on the focal plane. After extracting the patterns and comparing the change in spacings, we can measure the flatness to high precision. In method 1, the regular dots are kept in high sub micron precision and cover the whole focal plane. In method 2, no high precision for the grid is required. Instead, we use a precise XY stage moves the pattern across the whole focal plane and comparing the variations of the spacing when it is imaged by different CCDs. Simulation and real measurements show that the two methods work very well for our purpose, and are in good agreement with the direct optical measurements.

  17. A fast auto-focusing technique for the long focal lens TDI CCD camera in remote sensing applications

    Science.gov (United States)

    Wang, Dejiang; Ding, Xu; Zhang, Tao; Kuang, Haipeng

    2013-02-01

    The key issue in automatic focus adjustment for long focal lens TDI CCD camera in remote sensing applications is to achieve the optimum focus position as fast as possible. Existing auto-focusing techniques consume too much time as the mechanical focusing parts of the camera move in steps during the searching procedure. In this paper, we demonstrate a fast auto-focusing technique, which employs the internal optical elements and the TDI CCD itself to directly sense the deviations in back focal distance of the lens and restore the imaging system to a best-available focus. It is particularly advantageous for determination of the focus, due to that the relative motion between the TDI CCD and the focusing element can proceed without interruption. Moreover, the theoretical formulas describing the effect of imaging motion on the focusing precision and the effective focusing range are also developed. Finally, an experimental setup is constructed to evaluate the performance of the proposed technique. The results of the experiment show a ±5 μm precision of auto-focusing in a range of ±500 μmdefocus, and the searching procedure could be accomplished within 0.125 s, which leads to remarkable improvement on the real-time imaging capability for high resolution TDI CCD camera in remote sensing applications.

  18. Research on detecting heterogeneous fibre from cotton based on linear CCD camera

    Science.gov (United States)

    Zhang, Xian-bin; Cao, Bing; Zhang, Xin-peng; Shi, Wei

    2009-07-01

    The heterogeneous fibre in cotton make a great impact on production of cotton textile, it will have a bad effect on the quality of product, thereby affect economic benefits and market competitive ability of corporation. So the detecting and eliminating of heterogeneous fibre is particular important to improve machining technics of cotton, advance the quality of cotton textile and reduce production cost. There are favorable market value and future development for this technology. An optical detecting system obtains the widespread application. In this system, we use a linear CCD camera to scan the running cotton, then the video signals are put into computer and processed according to the difference of grayscale, if there is heterogeneous fibre in cotton, the computer will send an order to drive the gas nozzle to eliminate the heterogeneous fibre. In the paper, we adopt monochrome LED array as the new detecting light source, it's lamp flicker, stability of luminous intensity, lumens depreciation and useful life are all superior to fluorescence light. We analyse the reflection spectrum of cotton and various heterogeneous fibre first, then select appropriate frequency of the light source, we finally adopt violet LED array as the new detecting light source. The whole hardware structure and software design are introduced in this paper.

  19. Optical Readout of a Two Phase Liquid Argon TPC using CCD Camera and TGEMs

    CERN Document Server

    Mavrokoridis, K; Carroll, J; Lazos, M; McCormick, K J; Smith, N A; Touramanis, C; Walker, J

    2014-01-01

    This paper presents a preliminary study into the use of CCDs to image secondary scintillation light generated by Thick Gas Electron Multipliers (TGEMs) in a two phase LAr TPC. A Sony ICX285AL CCD chip was mounted above a double TGEM in the gas phase of a 40 litre two-phase LAr TPC with the majority of the camera electronics positioned externally via a feedthrough. An Am-241 source was mounted on a rotatable motion feedthrough allowing the positioning of the alpha source either inside or outside of the field cage. Developed for and incorporated into the TPC design was a novel high voltage feedthrough featuring LAr insulation. Furthermore, a range of webcams were tested for operation in cryogenics as an internal detector monitoring tool. Of the range of webcams tested the Microsoft HD-3000 (model no:1456) webcam was found to be superior in terms of noise and lowest operating temperature. In ambient temperature and atmospheric pressure 1 ppm pure argon gas, the TGEM gain was approximately 1000 and using a 1 msec...

  20. 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

  1. Development of the data acquisition system for the x-ray CCD camera (SXI) onboard ASTRO-H

    Science.gov (United States)

    Fujinaga, Takahisa; Anabuki, Naohisa; Aoyama, Shoichi; Kawano, Hidenori; Ikeda, Shoma; Iwai, Masachika; Ozaki, Masanobu; Dotani, Tadayasu; Natsukari, Chikara; Matsuta, Keiko; Shimizu, Kazuma; Nakajima, Hiroshi; Hayashida, Kiyoshi; Tsunemi, Hiroshi; Ueda, Shutaro; Komatsu, Shoji; Murayoshi, Taku; Mori, Koji; Watanabe, Tatsuo; Uchida, Hiroyuki; Ohnishi, Takao; Hiraga, Junko S.

    2011-09-01

    We present the development of the data acquisition system for the X-ray CCD camera (SXI: Soft X-ray Imager) onboard the ASTRO-H satellite. Two types of breadboard models (BBMs) of SXI electronics have been produced to verify the functions of each circuit board and to establish the data acquisition system from CCD to SpaceWire (SpW) I/F. Using BBM0, we verified the basic design of the CCD driver, function of the Δ∑-ADC, data acquisition of the frame image, and stability of the SpW communication. We could demonstrate the energy resolution of 164 eV (FWHM) at 5.9 keV. Using BBM1, we verified acquisition of the housekeeping information and the frame images.

  2. Detection of multimode spatial correlation in PDC and application to the absolute calibration of a CCD camera.

    Science.gov (United States)

    Brida, Giorgio; Degiovanni, Ivo Pietro; Genovese, Marco; Rastello, Maria Luisa; Ruo-Berchera, Ivano

    2010-09-27

    We propose and demonstrate experimentally a new method based on the spatial entanglement for the absolute calibration of analog detectors. The idea consists on measuring the sub-shot-noise intensity correlation between two branches of parametric down conversion, containing many pairwise correlated spatial modes. We calibrate a scientific CCD camera and a preliminary evaluation of the uncertainty indicates the metrological interest of the method.

  3. Tests of a new CCD-camera based neutron radiography detector system at the reactor stations in Munich and Vienna

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E.; Pleinert, H. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schillinger, B. [Technische Univ. Muenchen (Germany); Koerner, S. [Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria)

    1997-09-01

    The performance of the new neutron radiography detector designed at PSI with a cooled high sensitive CCD-camera was investigated under real neutronic conditions at three beam ports of two reactor stations. Different converter screens were applied for which the sensitivity and the modulation transfer function (MTF) could be obtained. The results are very encouraging concerning the utilization of this detector system as standard tool at the radiography stations at the spallation source SINQ. (author) 3 figs., 5 refs.

  4. Classification of volcanic ash particles from Sakurajima volcano using CCD camera image and cluster analysis

    Science.gov (United States)

    Miwa, T.; Shimano, T.; Nishimura, T.

    2012-12-01

    Quantitative and speedy characterization of volcanic ash particle is needed to conduct a petrologic monitoring of ongoing eruption. We develop a new simple system using CCD camera images for quantitatively characterizing ash properties, and apply it to volcanic ash collected at Sakurajima. Our method characterizes volcanic ash particles by 1) apparent luminance through RGB filters and 2) a quasi-fractal dimension of the shape of particles. Using a monochromatic CCD camera (Starshoot by Orion Co. LTD.) attached to a stereoscopic microscope, we capture digital images of ash particles that are set on a glass plate under which white colored paper or polarizing plate is set. The images of 1390 x 1080 pixels are taken through three kinds of color filters (Red, Green and Blue) under incident-light and transmitted-light through polarizing plate. Brightness of the light sources is set to be constant, and luminance is calibrated by white and black colored papers. About fifteen ash particles are set on the plate at the same time, and their images are saved with a bit map format. We first extract the outlines of particles from the image taken under transmitted-light through polarizing plate. Then, luminances for each color are represented by 256 tones at each pixel in the particles, and the average and its standard deviation are calculated for each ash particle. We also measure the quasi-fractal dimension (qfd) of ash particles. We perform box counting that counts the number of boxes which consist of 1×1 and 128×128 pixels that catch the area of the ash particle. The qfd is estimated by taking the ratio of the former number to the latter one. These parameters are calculated by using software R. We characterize volcanic ash from Showa crater of Sakurajima collected in two days (Feb 09, 2009, and Jan 13, 2010), and apply cluster analyses. Dendrograms are formed from the qfd and following four parameters calculated from the luminance: Rf=R/(R+G+B), G=G/(R+G+B), B=B/(R+G+B), and

  5. MOA-cam3: a wide-field mosaic CCD camera for a gravitational microlensing survey in New Zealand

    CERN Document Server

    Sako, T; Sasaki, M; Okajima, K; Abe, F; Bond, I A; Hearnshaw, J B; Itow, Y; Kamiya, K; Kilmartin, P M; Masuda, K; Matsubara, Y; Muraki, Y; Rattenbury, N J; Sullivan, D J; Sumi, T; Tristram, P; Yanagisawa, T; Yock, P C M

    2008-01-01

    We have developed a wide-field mosaic CCD camera, MOA-cam3, mounted at the prime focus of the Microlensing Observations in Astrophysics (MOA) 1.8-m telescope. The camera consists of ten E2V CCD4482 chips, each having 2kx4k pixels, and covers a 2.2 deg^2 field of view with a single exposure. The optical system is well optimized to realize uniform image quality over this wide field. The chips are constantly cooled by a cryocooler at -80C, at which temperature dark current noise is negligible for a typical 1-3 minute exposure. The CCD output charge is converted to a 16-bit digital signal by the GenIII system (Astronomical Research Cameras Inc.) and readout is within 25 seconds. Readout noise of 2--3 ADU (rms) is also negligible. We prepared a wide-band red filter for an effective microlensing survey and also Bessell V, I filters for standard astronomical studies. Microlensing studies have entered into a new era, which requires more statistics, and more rapid alerts to catch exotic light curves. Our new system is...

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

    Energy Technology Data Exchange (ETDEWEB)

    Soman, M.R., E-mail: m.r.soman@open.ac.uk [e2v centre for electronic imaging, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Hall, D.J.; Tutt, J.H.; Murray, N.J.; Holland, A.D. [e2v centre for electronic imaging, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Schmitt, T.; Raabe, J.; Schmitt, B. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2013-12-11

    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

  7. 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

  8. Laboratory characterization of a CCD camera system for retrieval of bi-directional reflectance distribution function

    Science.gov (United States)

    Nandy, Prabal; Thome, Kurtis J.; Biggar, Stuart F.

    1999-12-01

    The Remote Sensing Group of the Optical Science Center at the University of Arizona has developed a four-band, multi- spectral, wide-angle, imaging radiometer for the retrieval of the bi-directional reflectance distribution function (BRDF) for vicarious calibration applications. The system consists of a fisheye lens with four interference filters centered at 470 nm, 575 nm, 660 nm, and 835 nm for spectral selection and an astronomical grade 1024 X 1024-pixel, silicon CCD array. Data taken by the system fit in the array as a nominally 0.2 degree per pixel image. This imaging radiometer system has been used in support of the calibration of Landsat-5 and SPOT- satellite sensors. This paper presents the results of laboratory characterization of the system to determine linearity of the detector, point spread function (PSF) and polarization effects. The linearity study was done on detector array without the lens, using a spherical-integrating source with a 1.5-mm aperture. This aperture simulates a point source for distances larger than 60 cm. Data were collected as both a function of exposure time and distance from the source. The results of these measurements indicate that each detector of the array is linear to better than 0.5%. Assuming a quadratic response improves this fit to better than 0.1% over 88% of the upper end of the detector's dynamic range. The point spread function (PSF) of the lens system was measured using the sphere source and aperture with the full camera system operated at a distance of 700 mm from the source, thus the aperture subtends less than the field of view of one pixel. The PSF was measured for several field angles and the signal level was found to fall to less than 1% of the peak signal within 1.5-degrees (10 pixels) for the on-axis case. The effect of this PSF on the retrieval of modeled BRDFs is shown to be less than 0.2% out to view angles of 70 degrees. The final test presented is one to assess the polarization effects of the lens

  9. Sensors for 3D Imaging: Metric Evaluation and Calibration of a CCD/CMOS Time-of-Flight Camera

    Directory of Open Access Journals (Sweden)

    Fulvio Rinaudo

    2009-12-01

    Full Text Available 3D imaging with Time-of-Flight (ToF cameras is a promising recent technique which allows 3D point clouds to be acquired at video frame rates. However, the distance measurements of these devices are often affected by some systematic errors which decrease the quality of the acquired data. In order to evaluate these errors, some experimental tests on a CCD/CMOS ToF camera sensor, the SwissRanger (SR-4000 camera, were performed and reported in this paper. In particular, two main aspects are treated: the calibration of the distance measurements of the SR-4000 camera, which deals with evaluation of the camera warm up time period, the distance measurement error evaluation and a study of the influence on distance measurements of the camera orientation with respect to the observed object; the second aspect concerns the photogrammetric calibration of the amplitude images delivered by the camera using a purpose-built multi-resolution field made of high contrast targets.

  10. Sensors for 3D Imaging: Metric Evaluation and Calibration of a CCD/CMOS Time-of-Flight Camera.

    Science.gov (United States)

    Chiabrando, Filiberto; Chiabrando, Roberto; Piatti, Dario; Rinaudo, Fulvio

    2009-01-01

    3D imaging with Time-of-Flight (ToF) cameras is a promising recent technique which allows 3D point clouds to be acquired at video frame rates. However, the distance measurements of these devices are often affected by some systematic errors which decrease the quality of the acquired data. In order to evaluate these errors, some experimental tests on a CCD/CMOS ToF camera sensor, the SwissRanger (SR)-4000 camera, were performed and reported in this paper. In particular, two main aspects are treated: the calibration of the distance measurements of the SR-4000 camera, which deals with evaluation of the camera warm up time period, the distance measurement error evaluation and a study of the influence on distance measurements of the camera orientation with respect to the observed object; the second aspect concerns the photogrammetric calibration of the amplitude images delivered by the camera using a purpose-built multi-resolution field made of high contrast targets.

  11. Flat Field Anomalies in an X-ray CCD Camera Measured Using a Manson X-ray Source

    Energy Technology Data Exchange (ETDEWEB)

    M. J. Haugh and M. B. Schneider

    2008-10-31

    The Static X-ray Imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the X-rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The CCD chip is an X-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 μm square pixels, and 15 μm thick. A multi-anode Manson X-ray source, operating up to 10kV and 10W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/ΔE≈10. The X-ray beam intensity was measured using an absolute photodiode that has accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The X-ray beam provides full CCD illumination and is flat, within ±1% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an X-ray CCD imager. These errors are quite different from those found in a visible CCD imager.

  12. MISR Level 1A CCD Science data, all cameras V002

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the Reformatted Annotated Level 1A product for the CCD science data. The data numbers (DN) have been commuted from 12-bit numbers to 16-bit byte aligned...

  13. Optical measurement of the pointing stability of the SOFIA Telescope using a fast EM-CCD camera

    Science.gov (United States)

    Pfüller, Enrico; Wolf, Jürgen; Röser, Hans-Peter

    2010-07-01

    The goal of the Stratospheric Observatory for Infrared Astronomy (SOFIA) is to point its airborne telescope at astronomical targets stable within 0.2 arcseconds (rms). However, the pointing stability will be affected in flight by aircraft vibrations and movements and constantly changing aerodynamic conditions within the open telescope compartment. Model calculations indicate that initially the deviations from targets may be at the order of several arcseconds. The plan is to carefully analyse and characterize all disturbances and then gradually fine tune the telescope's attitude control system to improve the pointing stability. To optically measure how star images change their position in the focal plane, an Andor DU-888 electronmultiplying (EM) CCD camera will be mounted to the telescope instead of its standard tracking camera. The new camera, dubbed Fast Diagnostic Camera (FDC) has been extensively tested and characterized in the laboratory and on ground based telescopes. In ground tests on the SOFIA telescope system it proofed its capabilities by sampling star images with frame rates up to 400 frames per second. From this data the star's location (centroid) in the focal plane can be calculated every 1/400th second and by means of a Fourier transformation, the star's movement power spectrum can be derived for frequencies up to 200 Hz. Eigenfrequencies and the overall shape of the measured spectrum confirm the previous model calculations. With known disturbances introduced to the telescope's fine drive system, the FDC data can be used to determine the system's transfer function. These data, when measured in flight will be critical for the refinement of the attitude control system. Another subsystem of the telescope that was characterized using FDC data was the chopping secondary mirror. By monitoring a star centroid at high speed while chopping, the chopping mechanism and its properties could be analyzed. This paper will describe the EM-CCD camera and its

  14. A positioning model of a two CCD camera coordinate system with an alternate-four-matrix look-up table algorithm

    Science.gov (United States)

    Lin, Chern-Sheng; Chen, Chia-Tse; Wei, Tzu-Chi; Chen, Wei-Lung; Chang, Chia-Chang

    2010-12-01

    This study proposes a novel positioning model of a two CCD camera coordinate system with an alternate-four-matrix (AFM) look-up table (LUT) algorithm. Two CCD cameras are set on both sides of a large scale screen and used to aid the position measures of targets. The coordinate position of the object in a specified space can be obtained by using different viewing angles of the two cameras and the AFMLUT method. The right camera is in charge of detecting the intermediate block near the right side and the dead zone of the left camera, using the first and the second matrix LUTs. The left camera is in charge of detecting the other parts, using the third and the fourth matrix LUTs. The results indicate that this rapid mapping and four matrix memory allocation method has good accuracy (positioning error <2%) and stability when operating a human-machine interface system.

  15. Modelling of the over-exposed pixel area of CCD cameras caused by laser dazzling

    NARCIS (Netherlands)

    Benoist, K.W.; Schleijpen, R.M.A.

    2014-01-01

    A simple model has been developed and implemented in Matlab code, predicting the over-exposed pixel area of cameras caused by laser dazzling. Inputs of this model are the laser irradiance on the front optics of the camera, the Point Spread Function (PSF) of the used optics, the integration time of t

  16. Modelling of the over-exposed pixel area of CCD cameras caused by laser dazzling

    NARCIS (Netherlands)

    Benoist, K.W.; Schleijpen, R.M.A.

    2014-01-01

    A simple model has been developed and implemented in Matlab code, predicting the over-exposed pixel area of cameras caused by laser dazzling. Inputs of this model are the laser irradiance on the front optics of the camera, the Point Spread Function (PSF) of the used optics, the integration time of t

  17. Variable high-resolution color CCD camera system with online capability for professional photo studio application

    Science.gov (United States)

    Breitfelder, Stefan; Reichel, Frank R.; Gaertner, Ernst; Hacker, Erich J.; Cappellaro, Markus; Rudolf, Peter; Voelk, Ute

    1998-04-01

    Digital cameras are of increasing significance for professional applications in photo studios where fashion, portrait, product and catalog photographs or advertising photos of high quality have to be taken. The eyelike is a digital camera system which has been developed for such applications. It is capable of working online with high frame rates and images of full sensor size and it provides a resolution that can be varied between 2048 by 2048 and 6144 by 6144 pixel at a RGB color depth of 12 Bit per channel with an also variable exposure time of 1/60s to 1s. With an exposure time of 100 ms digitization takes approx. 2 seconds for an image of 2048 by 2048 pixels (12 Mbyte), 8 seconds for the image of 4096 by 4096 pixels (48 Mbyte) and 40 seconds for the image of 6144 by 6144 pixels (108 MByte). The eyelike can be used in various configurations. Used as a camera body most commercial lenses can be connected to the camera via existing lens adaptors. On the other hand the eyelike can be used as a back to most commercial 4' by 5' view cameras. This paper describes the eyelike camera concept with the essential system components. The article finishes with a description of the software, which is needed to bring the high quality of the camera to the user.

  18. Implementation of a parallel-beam optical-CT apparatus for three-dimensional radiation dosimetry using a high-resolution CCD camera

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wen-Tzeng [Department of Computer Science and Information Engineering, Minghsin University of Science and Technology, Taiwan, ROC (China); Chen, Chin-Hsing [Department of Management Information Systems, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC (China); Hung, Chao-Nan; Tuan, Chiu-Ching [Graduate Institute of Computer and Communication Engineering, National Taipei University of Technology, Taiwan, ROC (China); Chang, Yuan-Jen, E-mail: ronchang@ctust.edu.tw [Department of Management Information Systems, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC (China); Institute of Biomedical Engineering and Materials Science, Central Taiwan University of Science and Technology, Taichung, Taiwan, ROC (China)

    2015-06-01

    In this study, a charge-coupled device (CCD) camera with 2-megapixel (1920×1080-pixel) and 12-bit resolution was developed for optical computed tomography(optical CT). The signal-to-noise ratio (SNR) of our system was 30.12 dB, better than that of commercially available CCD cameras (25.31 dB). The 50% modulation transfer function (MTF50) of our 1920×1080-pixel camera gave a line width per picture height (LW/PH) of 745, which is 73% of the diffraction-limited resolution. Compared with a commercially available 1-megapixel CCD camera (1296×966-pixel) with a LW/PH=358 and 46.6% of the diffraction-limited resolution, our camera system provided higher spatial resolution and better image quality. The NIPAM gel dosimeter was used to evaluate the optical CT with a 2-megapixel CCD. A clinical five-field irradiation treatment plan was generated using the Eclipse planning system (Varian Corp., Palo Alto, CA, USA). The gel phantom was irradiated using a 6-MV Varian Clinac IX linear accelerator (Varian). The measured NIPAM gel dose distributions and the calculated dose distributions, generated by the treatment planning software (TPS), were compared using the 3% dose-difference and 3 mm distance-to-agreement criteria. The gamma pass rate was as high as 98.2% when 2-megapixel CCD camera was used in optical CT. However, the gamma pass rate was only 96.0% when a commercially available 1-megapixel CCD camera was used. - Highlights: • An optical CT system with a 2-megapixel CCD showed high uniformity of reconstructed images of the gel phantom. • The gamma pass rate was as high as 98.2% with the 3% dose difference and 3 mm dose to agreement criteria. • Our CCD with 12-bit information could guarantee better SNR performance, of 30.12 dB. • Our 2-megapixel CCD camera gave a LW/PH of 745, 73% of the diffraction-limited resolution.

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

    Science.gov (United States)

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

    2005-04-01

    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 2×107 cm s, 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 (1300×1340 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 1200 rpm. 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.

  20. 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.

  1. Compact pnCCD-based X-ray camera with high spatial and energy resolution: a color X-ray camera.

    Science.gov (United States)

    Scharf, O; Ihle, S; Ordavo, I; Arkadiev, V; Bjeoumikhov, A; Bjeoumikhova, S; Buzanich, G; Gubzhokov, R; Günther, A; Hartmann, R; Kühbacher, M; Lang, M; Langhoff, N; Liebel, A; Radtke, M; Reinholz, U; Riesemeier, H; Soltau, H; Strüder, L; Thünemann, A F; Wedell, R

    2011-04-01

    For many applications there is a requirement for nondestructive analytical investigation of the elemental distribution in a sample. With the improvement of X-ray optics and spectroscopic X-ray imagers, full field X-ray fluorescence (FF-XRF) methods are feasible. A new device for high-resolution X-ray imaging, an energy and spatial resolving X-ray camera, is presented. The basic idea behind this so-called "color X-ray camera" (CXC) is to combine an energy dispersive array detector for X-rays, in this case a pnCCD, with polycapillary optics. Imaging is achieved using multiframe recording of the energy and the point of impact of single photons. The camera was tested using a laboratory 30 μm microfocus X-ray tube and synchrotron radiation from BESSY II at the BAMline facility. These experiments demonstrate the suitability of the camera for X-ray fluorescence analytics. The camera simultaneously records 69,696 spectra with an energy resolution of 152 eV for manganese K(α) with a spatial resolution of 50 μm over an imaging area of 12.7 × 12.7 mm(2). It is sensitive to photons in the energy region between 3 and 40 keV, limited by a 50 μm beryllium window, and the sensitive thickness of 450 μm of the chip. Online preview of the sample is possible as the software updates the sums of the counts for certain energy channel ranges during the measurement and displays 2-D false-color maps as well as spectra of selected regions. The complete data cube of 264 × 264 spectra is saved for further qualitative and quantitative processing.

  2. Digital image measurement of specimen deformation based on CCD cameras and Image J software: an application to human pelvic biomechanics

    Science.gov (United States)

    Jia, Yongwei; Cheng, Liming; Yu, Guangrong; Lou, Yongjian; Yu, Yan; Chen, Bo; Ding, Zuquan

    2008-03-01

    A method of digital image measurement of specimen deformation based on CCD cameras and Image J software was developed. This method was used to measure the biomechanics behavior of human pelvis. Six cadaveric specimens from the third lumbar vertebra to the proximal 1/3 part of femur were tested. The specimens without any structural abnormalities were dissected of all soft tissue, sparing the hip joint capsules and the ligaments of the pelvic ring and floor. Markers with black dot on white background were affixed to the key regions of the pelvis. Axial loading from the proximal lumbar was applied by MTS in the gradient of 0N to 500N, which simulated the double feet standing stance. The anterior and lateral images of the specimen were obtained through two CCD cameras. Based on Image J software, digital image processing software, which can be freely downloaded from the National Institutes of Health, digital 8-bit images were processed. The procedure includes the recognition of digital marker, image invert, sub-pixel reconstruction, image segmentation, center of mass algorithm based on weighted average of pixel gray values. Vertical displacements of S1 (the first sacral vertebrae) in front view and micro-angular rotation of sacroiliac joint in lateral view were calculated according to the marker movement. The results of digital image measurement showed as following: marker image correlation before and after deformation was excellent. The average correlation coefficient was about 0.983. According to the 768 × 576 pixels image (pixel size 0.68mm × 0.68mm), the precision of the displacement detected in our experiment was about 0.018 pixels and the comparatively error could achieve 1.11\\perthou. The average vertical displacement of S1 of the pelvis was 0.8356+/-0.2830mm under vertical load of 500 Newtons and the average micro-angular rotation of sacroiliac joint in lateral view was 0.584+/-0.221°. The load-displacement curves obtained from our optical measure system

  3. Dose response characteristics of a novel CCD camera-based electronic portal imaging device comparison with OCTAVIUS detector.

    Science.gov (United States)

    Anvari, Akbar; Aghamiri, Seyed Mahmoud Reza; Mahdavi, Seyed Rabie; Alaei, Parham

    2015-01-01

    Dosimetric properties of a CCD camera-based Electronic Portal Imaging Device (EPID) for clinical dosimetric application have been evaluated. Characteristics obtained by EPID also compared with commercial 2D array of ion chambers. Portal images acquired in dosimetry mode then exported raw fluence or uncorrected images were investigated. Integration time of image acquisition mode has adjusted on 1 s per frame. As saturation of camera of the EPID, dose response does not have linear behavior. The slight nonlinearity of the camera response can be corrected by a logarithmic expression. A fourth order polynomial regression model with coefficient of determination of 0.998 predicts a response to absolute dose values at less than 50 cGy. A field size dependent response of up to 7% (0.99-1.06) relative OCTAVIUS detector measurement was found. The EPID response can be fitted by a cubic regression for field size changes, yielded coefficient of determination of 0.999. These results indicate that the EPID is well suited for accurate dosimetric purposes, the major limitation currently being due to integration time and dead-time in frame acquisition.

  4. Developments of engineering model of the X-ray CCD camera of the MAXI experiment onboard the International Space Station

    CERN Document Server

    Miyata, E; Kamazuka, T; Akutsu, D; Kouno, H; Tsunemi, H; Matsuoka, M; Tomida, H; Ueno, S; Hamaguchi, K; Tanaka, I

    2002-01-01

    MAXI, Monitor of All-sky X-ray Image, is an X-ray observatory on the Japanese Experimental Module (JEM) Exposed Facility (EF) on the International Space Station (ISS). MAXI is a slit scanning camera which consists of two kinds of X-ray detectors: one is a one-dimensional position-sensitive proportional counter with a total area of approx 5000 cm sup 2 , the Gas Slit Camera (GSC), and the other is an X-ray CCD array with a total area approx 200 cm sup 2 , the Solid-state Slit Camera (SSC). The GSC subtends a field of view with an angular dimension of 1 deg. x180 deg. while the SSC subtends a field of view with an angular dimension of 1 deg. times a little less than 180 deg. . In the course of one station orbit, MAXI can scan almost the entire sky with a precision of 1 deg. and with an X-ray energy range 0.5-30 keV. We have developed an engineering model (EM) for all components of the SSC. Their performance test is underway. We have also developed several kinds of CCDs fabricated from different wafers. Since th...

  5. Development of the control circuits for the TID-CCD stereo camera of the Chang'E-2 satellite based on FPGAs

    Science.gov (United States)

    Duan, Yong-Qiang; Gao, Wei; Qiao, Wei-Dong; Wen, De-Sheng; Zhao, Bao-Chang

    2013-09-01

    The TDI-CCD Stereo Camera is the optical sensor on the Chang'E-2 (CE-2) satellite created for the Chinese Lunar Exploration Program. The camera was designed to acquire three-dimensional stereoscopic images of the lunar surface based upon three-line array photogrammetric theory. The primary objective of the camera is, (1) to obtain about 1-m pixel spatial resolution images of the preparative landing location from an ellipse orbit at an altitude of ~15km, and (2) to obtain about 7-m pixel spatial resolution global images of the Moon from a circular orbit at an altitude of ~100km. The focal plane of the camera is comprised of two TDI-CCDs. The control circuits of the camera are designed based on two SRAM-type FPGAs, XQR2V3000-4CG717. In this paper, a variable frequency control and multi-tap data readout technology for the TDI-CCD is presented, which is able to change the data processing capabilities according to the different orbit mode for the TDI-CCD stereo camera. By this way, the data rate of the camera is extremely reduced from 100Mbps to 25Mbps at high orbit mode, which is benefit to raise the reliability of the image transfer. The results of onboard flight validate that the proposed methodology is reasonable and reliable.

  6. Million-frame-per-second CCD camera with 16 frames of storage

    Science.gov (United States)

    Howard, Nathan E.; Gardner, David W.; Snyder, Donald R.

    1997-12-01

    Ultrafast imaging is an important need for the development, control, and evaluation of modern air-deliverable weapons systems. Recent advances in optical imaging such as speckle interferometry can potentially improve DoD capability to deliver munitions and armaments to targets at long ranges, and under adverse seeing conditions. Moderate density arrays of at least 100 by 100 pixels and frame rates of at least 1 MHz are required. Ultrafast imaging is also required for flow field optical image analysis for hypersonic propulsion systems. Silicon Mountain Design (SMD) has built such an imager so that high quality images can be obtained for relatively low cost. The SMD-64k1M camera is capable of imaging 1,000,000 frames per second using a 256 by 256 array with the ability to store 16 frames with true 12 bits of dynamic range. This camera allows researchers to capture multiple high speed events using solid state technology housed in a 53 cubic inch package. A brief technical overview of the imager and results are presented in this paper.

  7. On Relativistic Disk Spectroscopy in Compact Objects with X-ray CCD Cameras

    Science.gov (United States)

    Miller, J. M.; D'Aì, A.; Bautz, M. W.; Bhattacharyya, S.; Burrows, D. N.; Cackett, E. M.; Fabian, A. C.; Freyberg, M. J.; Haberl, F.; Kennea, J.; Nowak, M. A.; Reis, R. C.; Strohmayer, T. E.; Tsujimoto, M.

    2010-12-01

    X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from most abundant metals. New CCDs also offer resolutions of 30-50 (E/ΔE), which is sufficient to detect lines in hot plasmas and to resolve many lines shaped by dynamical processes in accretion flows. The spectral capabilities of X-ray CCDs have been particularly important in detecting relativistic emission lines from the inner disks around accreting neutron stars and black holes. One drawback of X-ray CCDs is that spectra can be distorted by photon "pile-up," wherein two or more photons may be registered as a single event during one frame time. We have conducted a large number of simulations using a statistical model of photon pile-up to assess its impacts on relativistic disk line and continuum spectra from stellar-mass black holes and neutron stars. The simulations cover the range of current X-ray CCD spectrometers and operational modes typically used to observe neutron stars and black holes in X-ray binaries. Our results suggest that severe photon pile-up acts to falsely narrow emission lines, leading to falsely large disk radii and falsely low spin values. In contrast, our simulations suggest that disk continua affected by severe pile-up are measured to have falsely low flux values, leading to falsely small radii and falsely high spin values. The results of these simulations and existing data appear to suggest that relativistic disk spectroscopy is generally robust against pile-up when this effect is modest.

  8. 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.

  9. 一种新的CCD相机与激光相机的标定方法%A New Calibration Method for CCD Camera and Laser Camera

    Institute of Scientific and Technical Information of China (English)

    桑瑞娟

    2012-01-01

    In the intelligent robot' s navigation and positioning system, in order to get more comprehen- sive and accurate information, people generally use multiple sensors to get information, therefore fuse da- tas are needed, the major problem of the fusion of multiple sensors is the coordinates calibration between them. In consideration of the coordinate calibration between CCD camera and laser camera: firstly, the information of special points in the calibration object ject was built, secondly, the corners were detected plane were removed, finally the rotation matrix and was got, then the pane equation of the calibration ob- by harris method, the points which were not in the translation matrix were solved. The results show that%在智能机器人的导航定位系统中,为了得到的信息更加全面和准确,一般采用多种传感器共同获取信息,这就需要进行数据的融合,多传感器的联合标定是数据融合的关键问题。针对CCD相机和激光相机进行标定,首先采集标定靶特殊点的信息,建立标定靶平面方程,其次用harris角点检测算法检测角点,去除不符合平面方程的点,最后求解旋转矩阵和平移矩阵。实验结果表明,该方法能有效去除混合像素,标定结果更加准确。

  10. Tracking of Human Gestures in RGB Image Sequence Based on Statistical Inference and Three-Dimensional Human Model Taken with Ocellar CCD Camera

    OpenAIRE

    我如古, 博之; 山城, 毅; 渡久地, 實; Ganeko, Hiroyuki; Yamashiro, Tsuyoshi; Toguchi, Minoru

    1999-01-01

    Many methods for tracking of Three-Dimensional human gestures have been proposed by using multiview scheme. However, at the present state these methods have been very far from the stage of practical application due to its high-cost. This paper describes a new method of Three-Dimensional human gesture from image sequence taken with Ocellar CCD camera. This tracking system is composed based on statistical inference and Three-Dimensional human model, and the Occlusion problem is solved by bottom...

  11. High-resolution application of YAG:Ce and LuAG:Ce imaging detectors with a CCD X-ray camera

    Science.gov (United States)

    Touš, Jan; Horváth, Martin; Pína, Ladislav; Blažek, Karel; Sopko, Bruno

    2008-06-01

    A high-resolution CCD X-ray camera based on YAG:Ce or LuAG:Ce thin scintillators is presented. High-resolution in low-energy X-ray radiation is proved with several objects. The spatial resolution achieved in the images is about 1 μm. The high-resolution imaging system is a combination of a high-sensitivity digital CCD camera and an optical system with a thin scintillator-imaging screen. The screen can consist of YAG:Ce or LuAG:Ce inorganic scintillator [J.A. Mares, Radiat. Meas. 38 (2004) 353]. These materials have the advantages of mechanical and chemical stability and non-hygroscopicity. The high-resolution imaging system can be used with different types of radiation (X-ray, electrons, UV, and VUV [M. Nikl, Meas. Sci. Technol. 17 (2006) R37]). The objects used for the imaging tests are grids and small animals with features of several microns in size. The resolution capabilities were tested using different types of CCD cameras and scintillation imaging screens.

  12. Near infrared thermography by CCD cameras and application to first wall components of Tore Supra tokamak; Thermographie proche infrarouge par cameras CCD et application aux composants de premiere paroi du tokamak Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, F.

    1996-06-07

    In the Tokamak TORE-SUPRA, the plasma facing components absorbs and evacuate (active cooling) high power fluxes (up to 10 MW/m{sup 2}). Their thermal behavior study is essential for the success of controlled thermonuclear fusion line. The first part is devoted to the study of power deposition on the TORE-SUPRA actively cooled limiters. A model of power deposition on one of the limiters is developed. It takes into account the magnetic topology and a description of the plasma edge. The model is validated with experimental calorimetric data obtained during a series of shots. This will allow to compare the surface temperature measurements with the predicted ones. The main purpose of this thesis was to evaluate and develop a new temperature measurement system. It works in the near infrared range (890 nm) and is designed to complete the existing thermographic diagnostic of TORE-SUPRA. By using the radiation laws (for a blackbody and the plasma) and the laboratory calibration one can estimate the surface temperature of the observed object. We evaluate the performances and limits of such a device in the harsh conditions encountered in a Tokamak environment. On the one hand, in a quasi ideal situation, this analysis shows that the range of measurements is 600 deg. C to 2500 deg. C. On the other hand, when one takes into account of the plasma radiation (with an averaged central plasma density of 6.10{sup 19} m{sup -3}), we find that the minimum surface temperature rise to 900 deg. C instead of 700 deg. C. In the near future, according to the development of IR-CCD cameras working in the near infrared range up to 2 micrometers, we will be able to keep the good spatial resolution with an improved lower limit for the temperature down to 150 deg. C. The last section deals with a number of computer tools to process the images obtained from experiments on TORE-SUPRA. A pattern recognition application was developed to detect a complex plasma iso-intensity structure. 87 refs.

  13. Flat Field Anomalies in an X-ray CCD Camera Measured Using a Manson X-ray Source (HTPD 08 paper)

    Energy Technology Data Exchange (ETDEWEB)

    Haugh, M; Schneider, M B

    2008-04-28

    The Static X-ray Imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the X-rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The CCD chip is an X-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 {micro}m square pixels, and 15 {micro}m thick. A multi-anode Manson X-ray source, operating up to 10kV and 10W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/{Delta}E {approx} 10. The X-ray beam intensity was measured using an absolute photodiode that has accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The X-ray beam provides full CCD illumination and is flat, within {+-}1% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an X-ray CCD imager. These errors are quite different from those found in a visible CCD imager.

  14. Thermal design and testing of CCD for space camera%空间相机大功率CCD器件的热设计与热试验

    Institute of Scientific and Technical Information of China (English)

    陈立恒; 李延春; 罗志涛; 董吉洪; 王忠素; 徐抒岩

    2011-01-01

    对空间相机大功率CCD器件进行了热设计以解决其散热问题,为了验证热设计的合理性进行了CCD焦面组件的热试验.首先,介绍了以传导为主要散热措施的CCD器件热设计方案,CCD器件的热量主要通过热管传递到冷源;然后,针对整个焦面组件进行了试验规划,特别对模拟冷板进行了专门设计;最后,在真空环境下进行了综合试验.试验结果显示,功耗为10 W的CCD器件连续工作70 min,在12℃冷源的情况下,能够控制焦平面器件的温度<35℃.该试验验证了CCD焦面组件热设计的合理性,并为焦面组件热分析计算模型修正提供了依据.%A thermal control system for a high-power CCD space camera was designed, including a thermal test of the focal plane assembly for resolving the heat dissipation problem. First, the thermal design scheme of the CCD was examined, where the heat produced by the CCD was transferred to the cold source through a heat pipe. Then a thermal test of focal plane assembly was planned with the simulated cold source specially designed. Finally, the thermal test of focal plane assembly was performed in a vacuum to simulate its space environment and structure characteristics. The results show that the working temperature of a 10 W high-power CCD space camera can be kept below 35 ℃ when it has been working for 70 min continuously and has a 12 ℃ cool source. The thermal design of the CCD focal plane assembly for the space camera is feasible and acceptable. It can be used as a reference for the mode correction of focal plane assembly thermal analysis.

  15. 传输型CCD相机成像分辨率自动测试研究%Research on automatic testing of image resolution of transmission CCD camera

    Institute of Scientific and Technical Information of China (English)

    王锋; 高亚飞

    2013-01-01

    对CCD相机成像分辨率自动测试方法进行了研究,测试方案中改进设计了照相分辨率靶标,开展了数据分析处理,通过软硬件结合实现了对CCD相机整机分辨率的自动测试,结果数据经过专业测试比对确认有效。实验结果表明,方法客观、准确,能够避免以往人工测试分辨率带来的主观因素影响,具有很高的实用性。%The automatic testing method of an image resolution of CCD camera is researched. The photo resolution drone design is improved in the testing project. The data analyzing and processing is carried out,and the automatic testing of CCD camera resolution is realized through the combination of hardware and software. The effectiveness of the result data is verified by professional testing. The experiment results show that the method is impersonality and accurate,it can avoid the affect of subjec-tive factors brought by manual testing resolution,and has prominence practicability.

  16. 基于CCD摄像头的小区自动循迹停车系统%Cell automatically tracking parking system based on CCD camera

    Institute of Scientific and Technical Information of China (English)

    李兴泽; 王福平

    2013-01-01

    This paper designed a car automatic tracing system based on the CCD camera.The system could collect environmental information by the CCD camera and range by using the ultrasonic sensor.The host controller MC9S12XS128 controlled the steering gear and motor in the PID algorithm.This made the car move to the specified garage by automatic tracking.This system solved the problem caused by some private garages have a long distance from their residential district.The project made the parking easily and intelligently.%设计了一种基于CCD摄像头的小车自动循迹系统.该系统通过CCD摄像头进行环境信息采集,通过超声波传感器测距.主控器MC9S12XS128采用PID算法对舵机和电机进行控制,使小车从指定位置开始以自动的循迹的方式行驶到指定车库或停车位.解决了一些住宅小区私家车库或停车位距住宅楼较远,自驾车停车不方便问题,实现了小区私家车停车智能化.

  17. Extrapolation of contrail investigations by LIDAR to larger scale measurements. Analysis and calibration of CCD camera and satellite images

    Energy Technology Data Exchange (ETDEWEB)

    Sussmann, R.; Homburg, F.; Freudenthaler, V.; Jaeger, H. [Frauenhofer Inst. fuer Atmosphaerische Umweltforschung, Garmisch-Partenkirchen (Germany)

    1997-12-31

    The CCD image of a persistent contrail and the coincident LIDAR measurement are presented. To extrapolate the LIDAR derived optical thickness to the video field of view an anisotropy correction and calibration has to be performed. Observed bright halo components result from highly regular oriented hexagonal crystals with sizes of 200 {mu}m-2 mm. This explained by measured ambient humidities below the formation threshold of natural cirrus. Optical thickness from LIDAR shows significant discrepancies to the result from coincident NOAA-14 data. Errors result from anisotropy correction and parameterized relations between AVHRR channels and optical properties. (author) 28 refs.

  18. Restoration of dichromatic images gained from CCD/CMOS camera by iterative detection networks with fragmented marginalization at the symbol block level

    Science.gov (United States)

    Kekrt, Daniel; Klíma, Miloš; Fliegel, Karel

    2009-08-01

    Image capturing by CCD/CMOS cameras is encumbered with two fundamental perturbing influences. Time invariant blurring (image convolution with fixed kernel) and time variant noises. Both of these influences can be successfully eliminated by the iterative detection networks (IDNs), that effectively and suboptimally (iteratively) solve 2D MAP criterion through the image decomposition to the small areas. Preferably to the individual pixel level, if this allows the noise distribution (statistically independent noise). Nevertheless, this task is so extremely numerically exacting and therefore the contemporary IDNs are limited only for restorations of dichromatic images. The IDNs are composed of certain, as simple as possible, statistical devices (SISO modules) and can be separated into two basic groups with variable topology (exactly matched to the blurring kernel) and with fixed topology, same for all possible kernels. The paper deals with second group of IDNs, concretely with IDNs whose SISO modules are concatenated in three directions (horizontal, vertical and diagonal). Advantages of such ordering rests in the application flexibility (can be comfortable applied to many irregular cores) and also in the low exigencies to number of memory devices it the IDN. The mentioned IDN type will be implemented in the two different variants suppressing defocusing in the lens of CCD/CMOS sensing system and will be verified in the sphere of a dichromatic 2D barcode detection.

  19. PIV系统CCD相机位移调整机构的设计%Design of CCD Camera Displacement Adjusting Mechanism for PIV System

    Institute of Scientific and Technical Information of China (English)

    王成军; 江平

    2014-01-01

    In order to have a higher reliability,accuracy and stability in flow field test for 2D Particle Image Velocimetry (PIV) system,the CCD camera displacement adjusting mechanism was designed,according to the PIV system requirements and the function of flow field test working environment,then the structural design thought,composition,and capable functions achieved and its charac-teristics were expounded.Through the use of the mechanism for the flow field test,the result shows that using of the CCD camera dis-placement adjusting mechanism,can very well satisfy the job needs of PIV system in flow field test,while makes the whole system more simple,stable and efficient,and further makes flow field test results more reliable and accurate.%为使PIV (Particle Image Velocimetry)系统在流场测试中具有更高的可靠性、准确性和稳定性,根据PIV流场试验对CCD相机安装要求和工作环境的需求,设计了CCD相机位移调整机构,并阐述了该机构的设计思路、组成、能实现的功能及其特点。通过使用该机构进行流场试验,结果表明:采用该CCD相机位移调整机构,能很好地满足PIV系统在流场测试试验中的工作需要,使整个系统更加简单、稳定、高效,进而使流场测试结果更加可靠、准确。

  20. SU-F-BRA-16: Development of a Radiation Monitoring Device Using a Low-Cost CCD Camera Following Radionuclide Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Taneja, S; Fru, L Che; Desai, V; Lentz, J; Lin, C; Scarpelli, M; Simiele, E; Trestrail, A; Bednarz, B [University of Wisconsin, Madison, WI (United States)

    2015-06-15

    Purpose: It is now commonplace to handle treatments of hyperthyroidism using iodine-131 as an outpatient procedure due to lower costs and less stringent federal regulations. The Nuclear Regulatory Commission has currently updated release guidelines for these procedures, but there is still a large uncertainty in the dose to the public. Current guidelines to minimize dose to the public require patients to remain isolated after treatment. The purpose of this study was to use a low-cost common device, such as a cell phone, to estimate exposure emitted from a patient to the general public. Methods: Measurements were performed using an Apple iPhone 3GS and a Cs-137 irradiator. The charge-coupled device (CCD) camera on the phone was irradiated to exposure rates ranging from 0.1 mR/hr to 100 mR/hr and 30-sec videos were taken during irradiation with the camera lens covered by electrical tape. Interactions were detected as white pixels on a black background in each video. Both single threshold (ST) and colony counting (CC) methods were performed using MATLAB®. Calibration curves were determined by comparing the total pixel intensity output from each method to the known exposure rate. Results: The calibration curve showed a linear relationship above 5 mR/hr for both analysis techniques. The number of events counted per unit exposure rate within the linear region was 19.5 ± 0.7 events/mR and 8.9 ± 0.4 events/mR for the ST and CC methods respectively. Conclusion: Two algorithms were developed and show a linear relationship between photons detected by a CCD camera and low exposure rates, in the range of 5 mR/hr to 100-mR/hr. Future work aims to refine this model by investigating the dose-rate and energy dependencies of the camera response. This algorithm allows for quantitative monitoring of exposure from patients treated with iodine-131 using a simple device outside of the hospital.

  1. Modelling the spectral response of the Swift-XRT CCD camera: Experience learnt from in-flight calibration

    CERN Document Server

    Godet, O; Abbey, A F; Osborne, J P; Cusumano, G; Pagani, C; Capalbi, M; Perri, M; Page, K L; Burrows, D N; Campana, S; Hill, J E; Kennea, J A; Moretti, A

    2008-01-01

    (Abbreviated) We show that the XRT spectral response calibration was complicated by various energy offsets in photon counting (PC) and windowed timing (WT) modes related to the way the CCD is operated in orbit (variation in temperature during observations, contamination by optical light from the sunlit Earth and increase in charge transfer inefficiency). We describe how these effects can be corrected for in the ground processing software. We show that the low-energy response, the redistribution in spectra of absorbed sources, and the modelling of the line profile have been significantly improved since launch by introducing empirical corrections in our code when it was not possible to use a physical description. We note that the increase in CTI became noticeable in June 2006 (i.e. 14 months after launch), but the evidence of a more serious degradation in spectroscopic performance (line broadening and change in the low-energy response) due to large charge traps (i.e. faults in the Si crystal) became more signif...

  2. “嫦娥二号”卫星CCD立体相机的关键技术%Key Technologies of CE-2 CCD Stereo Camera

    Institute of Scientific and Technical Information of China (English)

    赵葆常; 唐茜; 薛彬

    2013-01-01

    文章介绍了中国两次绕月探测中 CCD 立体相机所采用的技术与创新,并与国际同类相机所获取的图像进行了比较;在此基础上详细介绍了“嫦娥二号”(CE-2)卫星CCD立体相机的综合创新集成技术--“单镜头两视角同轨立体成像、时间延迟积分图像传感器(TDICCD)推扫、速高比补偿”,并从工程目标与科学目标出发进行探测灵敏度及成像动态范围的需求分析;根据需求分析确定了总体技术方案,包括光、机、电的优化设计以及对月探测中首次采用TDICCD的技术困难与对策;特别讨论了速高比补偿的方案及实施途径,并进行了在轨试验验证。文章最后分别给出了虹湾地区成像分辨率为1.3m以及全月面分辨率为7m 的代表性图像,图像清晰、层次丰富,显示出中国在对月立体成像技术上取得了显著进步。%The paper describes the CCD-stereo camera’s novel techniques used in China’s two around-lunar reconnaissances and compares similar images of lunar terrain obtained by foreign cameras. The paper also details CCD stereo-camera’s overall scheme, i.e. synthetically integrating techniques of“same orbit stereo-imaging with two sight angles, TDICCD pushing scan and velocity/height ratio compensation”. It in-cludes the requirement analysis of the sensibility and imaging dynamical range for the sake of engineering and science goals. The overall scheme is established on the basis of the requirement analysis, including the opti-mizing designs with optics, machine and electronics and imaging capability analysis for this scheme. The scheme can fulfill the mission goals. The paper introduces the technical difficulties with time-delay-integration CCD for lunar high resolution stereo-imaging and the countermeasures employed, especially discusses the scheme and way for velocity/height ratio compensation and gives the executed validation on orbit. Finally, it shows

  3. Development of low-noise high-speed analog ASIC for X-ray CCD cameras and wide-band X-ray imaging sensors

    Science.gov (United States)

    Nakajima, Hiroshi; Hirose, Shin-nosuke; Imatani, Ritsuko; Nagino, Ryo; Anabuki, Naohisa; Hayashida, Kiyoshi; Tsunemi, Hiroshi; Doty, John P.; Ikeda, Hirokazu; Kitamura, Hisashi; Uchihori, Yukio

    2016-09-01

    We report on the development and performance evaluation of the mixed-signal Application Specific Integrated Circuit (ASIC) developed for the signal processing of onboard X-ray CCD cameras and various types of X-ray imaging sensors in astrophysics. The quick and low-noise readout is essential for the pile-up free imaging spectroscopy with a future X-ray telescope. Our goal is the readout noise of 5e- r . m . s . at the pixel rate of 1 Mpix/s that is about 10 times faster than those of the currently working detectors. We successfully developed a low-noise ASIC as the front-end electronics of the Soft X-ray Imager onboard Hitomi that was launched on February 17, 2016. However, it has two analog-to-digital converters per chain due to the limited processing speed and hence we need to correct the difference of gain to obtain the X-ray spectra. Furthermore, its input equivalent noise performance is not satisfactory (> 100 μV) at the pixel rate higher than 500 kpix/s. Then we upgrade the design of the ASIC with the fourth-order ΔΣ modulators to enhance its inherent noise-shaping performance. Its performance is measured using pseudo CCD signals with variable processing speed. Although its input equivalent noise is comparable with the conventional one, the integrated non-linearity (0.1%) improves to about the half of that of the conventional one. The radiation tolerance is also measured with regard to the total ionizing dose effect and the single event latch-up using protons and Xenon, respectively. The former experiment shows that all of the performances does not change after imposing the dose corresponding to 590 years in a low earth orbit. We also put the upper limit on the frequency of the latch-up to be once per 48 years.

  4. HiPERCAM: A high-speed, quintuple-beam CCD camera for the study of rapid variability in the Universe

    CERN Document Server

    Dhillon, V S; Bezawada, N; Black, M; Dixon, S; Gamble, T; Henry, D; Kerry, P; Littlefair, S P; Lunney, D W; Morris, T; Osborn, J; Wilson, R W

    2016-01-01

    HiPERCAM is a high-speed camera for the study of rapid variability in the Universe. The project is funded by a 3.5MEuro European Research Council Advanced Grant. HiPERCAM builds on the success of our previous instrument, ULTRACAM, with very significant improvements in performance thanks to the use of the latest technologies. HiPERCAM will use 4 dichroic beamsplitters to image simultaneously in 5 optical channels covering the u'g'r'i'z' bands. Frame rates of over 1000 per second will be achievable using an ESO CCD controller (NGC), with every frame GPS timestamped. The detectors are custom-made, frame-transfer CCDs from e2v, with 4 low-noise (2.5e-) outputs, mounted in small thermoelectrically-cooled heads operated at 180 K, resulting in virtually no dark current. The two reddest CCDs will be deep-depletion devices with anti-etaloning, providing high quantum efficiencies across the red part of the spectrum with no fringing. The instrument will also incorporate scintillation noise correction via the conjugate-p...

  5. Low Speed Wind Tunnel Facility (LSWTF)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: This facility consists of a large-scale, low-speed open-loop induction wind tunnel which has been modified to house a linear turbine cascade. A 125-hp...

  6. HiPERCAM: a high-speed quintuple-beam CCD camera for the study of rapid variability in the universe

    Science.gov (United States)

    Dhillon, Vikram S.; Marsh, Thomas R.; Bezawada, Naidu; Black, Martin; Dixon, Simon; Gamble, Trevor; Henry, David; Kerry, Paul; Littlefair, Stuart; Lunney, David W.; Morris, Timothy; Osborn, James; Wilson, Richard W.

    2016-08-01

    HiPERCAM is a high-speed camera for the study of rapid variability in the Universe. The project is funded by a ɛ3.5M European Research Council Advanced Grant. HiPERCAM builds on the success of our previous instrument, ULTRACAM, with very significant improvements in performance thanks to the use of the latest technologies. HiPERCAM will use 4 dichroic beamsplitters to image simultaneously in 5 optical channels covering the u'g'r'I'z' bands. Frame rates of over 1000 per second will be achievable using an ESO CCD controller (NGC), with every frame GPS timestamped. The detectors are custom-made, frame-transfer CCDs from e2v, with 4 low noise (2.5e-) outputs, mounted in small thermoelectrically-cooled heads operated at 180 K, resulting in virtually no dark current. The two reddest CCDs will be deep-depletion devices with anti-etaloning, providing high quantum efficiencies across the red part of the spectrum with no fringing. The instrument will also incorporate scintillation noise correction via the conjugate-plane photometry technique. The opto-mechanical chassis will make use of additive manufacturing techniques in metal to make a light-weight, rigid and temperature-invariant structure. First light is expected on the 4.2m William Herschel Telescope on La Palma in 2017 (on which the field of view will be 10' with a 0.3"/pixel scale), with subsequent use planned on the 10.4m Gran Telescopio Canarias on La Palma (on which the field of view will be 4' with a 0.11"/pixel scale) and the 3.5m New Technology Telescope in Chile.

  7. 基于OpenCV的CCD摄像机标定方法%Method of CCD Camera Calibration Based On OpenCV

    Institute of Scientific and Technical Information of China (English)

    雷铭哲; 孙少杰; 陈晋良; 陶磊; 魏坤

    2014-01-01

    计算机视觉在工业,农业,军事,交通等领域都有着广泛应用。摄像机标定是视觉系统的重要环节,也是研究的关键领域。以摄像机标定技术为研究对象,选取针孔成像模型,简述了世界坐标系、摄像机坐标系和图像坐标系及其相互间的位置关系,对标定过程进行了深入研究。特别地,为提高标定精度,充分考虑了透镜径向和切向畸变影响及其求解方法,制作了棋盘格平面标定模板,基于开放计算机视觉函数库(OpenCV)实现了摄像机标定。该标定算法能够充分发挥OpenCV函数库功能,对于图像处理与计算机视觉方面的应用设计具有实用价值。实验结果表明该方法取得了较高精度,能够满足视觉检测或其他计算机视觉系统的应用需要。%Computer vision has been widely used in industry,agriculture,military,transportation area and so on. Camera calibration is very important and also the key research field of vision system. This paper mainly researches on the method of CCD camera calibration,the pin-hole model has been introduced and applied in process of calibration. Specially,in order to improve the accuracy,both radial and tangential lens distortion have been taken into account during the implement of calibration based on OpenCV. This kind of arithmetic has practical value on the application design of image processing and computer vision,and experiment results show good precision,which can meet the application need of visual inspection or other vision systems well.

  8. The OCA CCD Camera Controller

    Science.gov (United States)

    1996-01-01

    several CCDs at the focal plane of a Schmidt telescope. These are examined in detail in the following paragraphs. Schmidt focal sphere: A typical " big ...40 50 Declination I in our case, field curvature is not seen at declinations higher than 35 degrees, so is not a real problem. A big advantage of...RAM to Accumulator 11 ANL Adata AND immediate data to Accumulator 2 12 ANIL. irecat.a AND Accumulator to direct byte 2 12 ANL direct.dAt NDimediate

  9. Design Study of An Automtic Forest Fire Monitoring System based on CCD Cameras and ArcObjects%基于CCD摄像机和ArcObjects的森林火灾自动监测系统的设计研究

    Institute of Scientific and Technical Information of China (English)

    窦长娥; 费鲜芸

    2011-01-01

    通过安装在监控地点的CCD摄像机,借助卫星遥感技术、图像处理技术以及网络通讯设施,结合ArcObjects组件开发方式,在探讨森林火灾自动监测系统总体框架的基础上,对系统数据库和核心模块功能进行分析设计,建立基于CCD摄像机和ArcObjects的森林火灾自动监测系统,解决了传统的以人工实地为主的监测方式,采用CCD摄像机视频监控,结合图像处理技术和人工智能技术,提高了视频监控系统的能力.%The system database and core module function were designed based on the discussion of the general framework of the Automatic Forest Fire Monitoring System (AFFMS) by using CCD cameras which were installed in monitoring spots, ArcObjects technologies, satellite remote sensing technology, image processing technology and network communication function. The automated monitoring system for forest fire disaster based on CCD camera and ArcObjects were set up to solve the traditional artificial field observation method. Using CCD camera video monitoring, and combining with image process technology and artificial intelligence technology, the ability of video monitoring system was enhanced.

  10. 高分辨率大面阵CCD相机高帧频设计及其非均匀性的校正%High-resolution large area CCD camera frame rate design and its non-uniformity correction

    Institute of Scientific and Technical Information of China (English)

    任航

    2013-01-01

    Using high-resolution full frame area array CCD FTF5066M as aerial image sensor of the camera, its frame rate is generally not more than 1 fps, which can not meet the high frame rate applications. Firstly, the full frame area array CCDFTF5066M drive circuit was introduced in this paper, and it was also been improved. Using CCD four output amplifiers to output at the same time, the highest frame rate reached 3.4 fps. Secondly, the timing of the CCD driver, front-end processing circuit, DC bias circuit, interface circuit of the four outputs were designed. The improved driver circuit could meet the application requirements of various aerial camera. Then the full frame area array CCDFTF5066M non-uniformity was analyzed, and a non-uniform response detection system was established. Using this system, the array CCD5066M's non-uniformity between the four quadrants and each pixel was tested separately. On the basis of CCD linear responsivity, two correction algorithm was proposed to correct the non-uniformity. At last, by correcting, the four quadrants's standard deviation of response sensitivity was reduced to the original's 1/13. Through the re-shoting of the identify rate board, it can seen that the array CCD's non-uniformity has been improved obviously.%  目前采用高分辨率全帧面阵CCD FTF5066M 作图像传感器的航拍相机帧频一般不超过1 fps,为了满足高帧频应用,文中首先介绍了全帧型面阵CCDFTF5066M的基本驱动电路,并对其进行了改进,利用CCD 4个输出放大器进行同时输出,使最高帧频达到了3.4 fps,介绍了4路输出时CCD驱动时序、前端处理电路、直流偏置电路、接口电路等的设计,改进后的驱动电路能满足多种航拍相机的应用要求。然后对全帧型面阵CCDFTF5066M的非均匀性进行了分析,并建立了一种响应非均匀性检测系统。利用该系统分别对面阵CCD5066M的4个象限之间的非均匀性和每个像元之间的非均匀

  11. Low Speed Automation, a French Initiative

    OpenAIRE

    Glaser, Sébastien; Cour, Maurice; NOUVELIERE, Lydie; LAMBERT, Alain; Nashashibi, Fawzi; Popieul, Jean-Christophe; Mourllion, Benjamin

    2012-01-01

    International audience; Nowadays, vehicle safety is constantly increasing thanks to the improvement of vehicle passive and active safety. However, on a daily usage of the car, traffic jams remains a problem. With limited space for road infrastructure, automation of the driving task on specific situation seems to be a possible solution. The French project ABV, which stands for low speed automation, tries to demonstrate the feasibility of the concept and to prove the benefits. In this article, ...

  12. The Ortega Telescope Andor CCD

    Science.gov (United States)

    Tucker, M.; Batcheldor, D.

    2012-07-01

    We present a preliminary instrument report for an Andor iKon-L 936 charge-couple device (CCD) being operated at Florida Tech's 0.8 m Ortega Telescope. This camera will replace the current Finger Lakes Instrumentation (FLI) Proline CCD. Details of the custom mount produced for this camera are presented, as is a quantitative and qualitative comparison of the new and old cameras. We find that the Andor camera has 50 times less noise than the FLI, has no significant dark current over 30 seconds, and has a smooth, regular flat field. The Andor camera will provide significantly better sensitivity for direct imaging programs and, once it can be satisfactorily tested on-sky, will become the standard imaging device on the Ortega Telescope.

  13. 基于结构光和单CCD相机的物体表面三维测量%A New Method of Automatic Measurement for 3D Surface by Using Structured Light,Single CCD Camera

    Institute of Scientific and Technical Information of China (English)

    牟元英; 徐春斌

    2001-01-01

    Non-contact automatic measurement for 3D surface is one of central tasks of computer vision.Arounding this task ,a new method of automatic measurement for 3D surface by using structured light 、single CCD camera and double orientations techniques is proposed in this paper.The stereo coordinates of 3D surface can be obtained through a sequence monocular images without determining the relative position between camera (CCD) and structured light projector.%非接触式物体表面三维自动测量是计算机视觉领域的中心任务之一,围绕这个问题,提出了一种利用结构光,单CCD相机和双定向技术实现物体表面三维自动测量的新方法。采用该方法,无需测定相机和结构光光截面之间的相对位置,在单目序列影像上就可测量出物体表面的三维坐标。

  14. Design of Hardware for CCD Video Surveillance Camera with External Synchronization Function%具有外同步功能的 CCD 视频监控摄像机硬件设计

    Institute of Scientific and Technical Information of China (English)

    国蓉; 焦旸; 高明; 杜玉军

    2014-01-01

    为了解决目标追踪中不同摄像机间识别目标的差异,在普通摄像机的基础上开发外同步功能。使用专用DSP微处理器CXD3172AR加EEPROM 的驱动方案,利用同步信号发生器和锁相环电路实现外同步功能。设计了信号处理电路,实现清晰的图像输出。实验结果表明,视频监控摄像机输出视频信号稳定,实现外同步功能,图像分辨率达752×528,输出帧率50帧/秒。%In order to solve the problem that the target identified by different cameras was discrepant during the process of tracking ,the external synchronization function is developed based on the common camera .Also ,a program is proposed ,taking CXD3172AR ,a microprocessor specially used in DSP and EEPROM as driver ,then using synchronous signal generator and phase locked loop circuit ,to achieve external synchronization .Meanwhile a signal processing circuit is designed to achieve the output of digital format . T he experimental results show that the video surveillance camera had the features of stable output signal ,external synchronization ,image resolution up to 752 × 528 and output frame rate up to 50 frames/s .

  15. 线阵近景数字测量相机的数码机背设计与实现%Design of Close-Range Measuring Linear CCD Camera Backs

    Institute of Scientific and Technical Information of China (English)

    张宝印; 陈向宁; 陈颖

    2011-01-01

    Owing to the characters of its broad visual field, high working efficiency and fast object detection, the close-range measuring digital camera has been widely used in ground photogrammetry. Kodar linear CCD KILl4403, which possesses plentiful pixels and high sensitivity, are very satisfied to as a image sensor of the close-range measuring camera. The circuit and printed circuit board of the camera back has been designed based on it, then the prototype has been made to verify the scheme. The experimental result showed that the scheme was feasible, and could provide an efficient digital camera backs for the close-range measuring camera.%线阵近景测量相机以大视场、高精度和高效率等优点,在数字近景摄影测量领域得到了广泛应用.Kodar公司KIL-14403线阵CCD作为线阵近景测量相机的图像传感器,具有像素多、灵敏度高等特点,非常适合近景数字摄影测量相机的要求.因此,针对KIL-14403线阵CCD设计了线阵近景测量相机的数码机背电子电路,完成了原理样机研制.经过实际测试,达到了预期效果,为近景摄影测量提供了一种高效的数字摄影测量相机的关键部件.

  16. Research on Tailoring Technology of Operation System of Medium-high Altitude Area Array CCD Aerial Camera%中高空面阵CCD航空相机操作系统裁剪技术研究

    Institute of Scientific and Technical Information of China (English)

    曹维国; 郑志峰; 杨海凝; 温培培; 段洁

    2015-01-01

    针对面阵CCD航空相机操作系统的实际需求,结合相机中PC104总线结构的硬件资源,对所采用的Linux系统进行实用性裁剪.采用粗粒度和细粒度相结合的裁剪方法,来增强Linux内核的抢占性,改善Linux内核的实时调度器的调度策略,以构建具有较强实施处理能力的嵌入式系统.在不同环境下,对系统的启动和任务响应性能的试验测试表明,裁剪后的系统稳定、可靠,且可达到启动时间小于5s,任务响应时间小于20ms的性能指标.%In view of the actual demand of operating system of the air plane array CCD camera, and combining with the hardware resources of the PC104 bus structure,the Linux system adopted in CCD camera is cut practically,which based on the tailoring method adopting the combination of coarse-grained and fine-grained to enhance the Linux kernel preemption.Through improving the scheduling strategy of Linux kernel scheduler,we build a embedded system with the strong implementation capacity.The system startup and task of the response performance test in different environment shows that the cut systems is stable, reliable, and can achieve the startup time less than 5s, the performance of the task response time less than 20ms.

  17. A Simple Method Based on the Application of a CCD Camera as a Sensor to Detect Low Concentrations of Barium Sulfate in Suspension

    Directory of Open Access Journals (Sweden)

    Joao Francisco Cajaiba da Silva

    2011-01-01

    Full Text Available The development of a simple, rapid and low cost method based on video image analysis and aimed at the detection of low concentrations of precipitated barium sulfate is described. The proposed system is basically composed of a webcam with a CCD sensor and a conventional dichroic lamp. For this purpose, software for processing and analyzing the digital images based on the RGB (Red, Green and Blue color system was developed. The proposed method had shown very good repeatability and linearity and also presented higher sensitivity than the standard turbidimetric method. The developed method is presented as a simple alternative for future applications in the study of precipitations of inorganic salts and also for detecting the crystallization of organic compounds.

  18. 数码航测中多拼CCD相机同步曝光方法及其实验分析%A method for synchronized exposure of multi-CCD cameras in digital phtogrammetry and its experimental analysis

    Institute of Scientific and Technical Information of China (English)

    石波; 李国玉; 王冬

    2012-01-01

    Equivalent large frame camera, composed of multiple CCD cameras and involving synchronized exposure as one of its key technologies, can form a wide field of view and play a significant role in digital programmetry. Therefore, the research on a synchronized exposure method was conducted with solid state Optronics relay as the key component in the paper, and furthermore, experiments on the performance of synchronous exposure were carried out The data were analyzed with statistical analysis method and the advantages , compared with those of the traditional electromagnetic relay methods, were verified. The experiment showed that the method could satisfy the requirements of large-scale digital photogrammetry.%多拼相机组合成等效大面阵相机,可以形成宽角视场,对于数码航测具有重要意义,其中同步曝光是其核心技术之一.本文研究了一种光耦继电器为核心部件的同步曝光方法,对同步曝光的性能进行了实验,利用统计分析的方法进行了数据分析,验证了相对于传统的电磁继电器方案的优越性,实验表明可以满足大比例尺数码航测的要求.

  19. Linear CCD attitude measurement system based on the identification of the auxiliary array CCD

    Science.gov (United States)

    Hu, Yinghui; Yuan, Feng; Li, Kai; Wang, Yan

    2015-10-01

    Object to the high precision flying target attitude measurement issues of a large space and large field of view, comparing existing measurement methods, the idea is proposed of using two array CCD to assist in identifying the three linear CCD with multi-cooperative target attitude measurement system, and to address the existing nonlinear system errors and calibration parameters and more problems with nine linear CCD spectroscopic test system of too complicated constraints among camera position caused by excessive. The mathematical model of binocular vision and three linear CCD test system are established, co-spot composition triangle utilize three red LED position light, three points' coordinates are given in advance by Cooperate Measuring Machine, the red LED in the composition of the three sides of a triangle adds three blue LED light points as an auxiliary, so that array CCD is easier to identify three red LED light points, and linear CCD camera is installed of a red filter to filter out the blue LED light points while reducing stray light. Using array CCD to measure the spot, identifying and calculating the spatial coordinates solutions of red LED light points, while utilizing linear CCD to measure three red LED spot for solving linear CCD test system, which can be drawn from 27 solution. Measured with array CCD coordinates auxiliary linear CCD has achieved spot identification, and has solved the difficult problems of multi-objective linear CCD identification. Unique combination of linear CCD imaging features, linear CCD special cylindrical lens system is developed using telecentric optical design, the energy center of the spot position in the depth range of convergence in the direction is perpendicular to the optical axis of the small changes ensuring highprecision image quality, and the entire test system improves spatial object attitude measurement speed and precision.

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

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Tong-Ding, E-mail: snuohui@126.com; Li, Bin-Kang; Yang, Shao-Hua; Guo, Ming-An; Yan, Ming

    2016-06-21

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

  1. Lunar Image Data Preprocessing and Quality Evaluation of CCD Stereo Camera on Chang'E-2%嫦娥二号CCD立体相机数据预处理与数据质量评价

    Institute of Scientific and Technical Information of China (English)

    刘建军; 任鑫; 谭旭; 李春来

    2013-01-01

    嫦娥二号是中国探月工程二期月面软着陆和巡视探测的先导星,经过为期半年多的科学探测,CCD立体相机获取了空间分辨率7 m的全月球影像数据,对于后续月球探测和月球科学研究具有非常重要的意义.本文介绍了CCD立体相机的数据获取、数据预处理、数据格式和数据质量情况,有助于月球科学家了解数据产品情况,挖掘数据中更多的科学信息,开展月球科学研究.%Chang'E-2 was launched on October 1st 2010, inaugurating the second phase of a three-step moon mission which will culminate in a soft-landing on the moon. After half a year's exploring, the globe image data of 7 m resolution had been acquired by CCD stereo camera on Chang'E-2. The image data acquiring and preprocessing, data format and quality are recommended, which are helpful for lunar scientists to understand and make use of these image data products, and to extract information for studying lunar science.

  2. CCD video camera system in the assessment of balance function Ye Shuangying%使用CCD摄像仪检测系统测定老年人体平衡能力的敏感性分析

    Institute of Scientific and Technical Information of China (English)

    叶双樱; 吴绍长; 潘君玲; 江依法; 周青

    2014-01-01

    目的 分析使用CCD摄像仪检测系统测定老年人平衡能力的敏感性,从而探讨其测定人体平衡功能的可能性. 方法 采用CCD摄像仪检测系统由CCD摄像仪.观察指标主要有:身体动摇角度(TSA)、身体动摇速度(TSS)和跌倒指数(FI).根据FI分为对照组和平衡功能障碍轻度、中度、重度组.平衡功能障碍组为丽水市第二人民医院老年科收治的脑血管意外患者42例,平均年龄(67.4±8.0)岁.对照组为健康体检志愿者42例,平均年龄(65.3±6.5)岁.所有参与者均Berg平衡量表评分,CCD摄像仪的测定TSA、TSS、FI,使用CCD摄像仪每人开眼(eo)检测3次,闭眼(ec)检测3次,取平均值. 结果 平衡功能障碍组与对照组相比,TSAeo、TSAec、TSSeo、TSSec、FIeo、FIec差异有统计学意义(P<0.01);Berg平衡量表评分差异有统计学意义(P<0.05).平衡功能障碍组中TSAeo、TSAec、TSSeo、TSSec轻度、中度、重度间均差异有统计学意义(P<0.05),重度与轻度间TSAeo、TSAec、TSSeo、TSSec有显著(P<0.01).Berg平衡量表评分重度与轻度间有差异(P<0.05). 结论 测定人体平衡功能CCD摄像仪检测系统敏感性较高,较Berg平衡量表CCD摄像仪具有更高的敏感度,值得临床推广.%Objective To probe into possibilities and sensitivity of CCD video camera system in the assessment of balance function.Methods The system is composed of a CCD video camera,a video image capture board and analysis software.Three indexes:Trunks,ayAngle (TSS Trunk Sway Speed(TSS) and fall index (FI).the normal group:FI≥I; mild group:0.7≤FI<I; moderate group:0.4≤FI<0.7; severe group:FI <0.4.Disorder of balance function group:42 patients with cerebrovascular accident,mean age of (67.4±8.0) years.Control group:42 healthy subjects,mean age of (65.3±6.5) years.All cases were measured by Berg balance scale and determinated three times by CCD video camera system with eye opening (eo) and eye closing

  3. Intensified CCD Image Sensor①

    Institute of Scientific and Technical Information of China (English)

    LIUJikun; ZHAOBaoyun

    1997-01-01

    Work has been done with extending the useful imaging and detection rage of CCD.This was accomplished through direct optical coupling and bonding of image intensifiers to the CCD.It has been shown that the useful range of a CCD may be extended two orders of magnitude using these techniques in coupling a microchannel plate image intensifier to the CCD array.All of these works were done with presently available CCD made by China

  4. Single Phase Permanent Magnet Low Speed Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Gao Lianxue

    2013-04-01

    Full Text Available In order to acquire a better cognition to the single phase permanent magnet low speed synchronous motor and validate the correctness of the motor mathematical model, the performances of the motor are tested with the single phase permanent magnet low speed synchronous motor whose type is 70TDY4, the corresponding simulations are done too. The resistance and the inductance of the single phase permanent magnet low speed synchronous motor are measured. According to the data of experiments and simulations, the static characteristics of the single phase permanent magnet low speed synchronous motor with the changes of the phase shift resistance and the phase shift capacitance are analysed, the results of experiments and simulations prove the correctness of the mathematics model.

  5. 高温物体成像时彩色CCD相机的自动调光方法%Automatic Light Adjustment Method for Color CCD Camera Used in Imaging of High-Temperature Object

    Institute of Scientific and Technical Information of China (English)

    李哲林; 夏琴香; 姜立军; 李一振; 宋阿生

    2013-01-01

    针对温度变化大的高温物体在CCD相机上成像时图像会发白或发黑,导致图像中物体特征被弱化这一问题,提出一种基于灰度均值的彩色CCD相机自动调光方法.文中首先阐述了CCD相机成像时物体热辐射对图像灰度的影响;然后分析了彩色CCD相机采集的850 ~1200℃高温物体图像的特点,建立了RGB基色图像灰度均值与积分时间的关系;最后提出一种自动调光方法,该方法通过采集一帧预测图像来计算物体所在的温度区间和最佳积分时间,根据最佳积分时间采集彩色图像,按照温度区间提取彩色图像对应的基色灰度图,并将其作为后续处理图像.实验结果表明,该调光方法对温度变化具有很好的鲁棒性,基于此方法的彩色CCD相机能采集到具有稳定灰度值的高温物体图像,有利于高温物体的几何测量和表面缺陷检测.%Due to the whitened or darkened CCD camera images of high-temperature objects with wide temperature change range, the object features in the images are weakened. In order to solve this problem, an automatic light adjustment method based on average gray value for color CCD camera is proposed. In the investigation, first, the effects of object heat radiation on the image gray during the imaging are discussed. Next, the image features of the object with the temperature of 850 ~ 1200℃ are analyzed. Then, the relationship between the average gray of RGB primary color images and the integral time is revealed. Finally, an automatic light adjustment method is constructed, which calculates the temperature zone and optimal integral time by using a prediction image frame, acquires the color image according to the optimal integral time, and extracts a proper primary gray image from the color image based on temperature zone for further usage. Experimental results show that the proposed method is robust to wide temperature change range and helps to acquire images with stable

  6. Testing fully depleted CCD

    Science.gov (United States)

    Casas, Ricard; Cardiel-Sas, Laia; Castander, Francisco J.; Jiménez, Jorge; de Vicente, Juan

    2014-08-01

    The focal plane of the PAU camera is composed of eighteen 2K x 4K CCDs. These devices, plus four spares, were provided by the Japanese company Hamamatsu Photonics K.K. with type no. S10892-04(X). These detectors are 200 μm thick fully depleted and back illuminated with an n-type silicon base. They have been built with a specific coating to be sensitive in the range from 300 to 1,100 nm. Their square pixel size is 15 μm. The read-out system consists of a Monsoon controller (NOAO) and the panVIEW software package. The deafualt CCD read-out speed is 133 kpixel/s. This is the value used in the calibration process. Before installing these devices in the camera focal plane, they were characterized using the facilities of the ICE (CSIC- IEEC) and IFAE in the UAB Campus in Bellaterra (Barcelona, Catalonia, Spain). The basic tests performed for all CCDs were to obtain the photon transfer curve (PTC), the charge transfer efficiency (CTE) using X-rays and the EPER method, linearity, read-out noise, dark current, persistence, cosmetics and quantum efficiency. The X-rays images were also used for the analysis of the charge diffusion for different substrate voltages (VSUB). Regarding the cosmetics, and in addition to white and dark pixels, some patterns were also found. The first one, which appears in all devices, is the presence of half circles in the external edges. The origin of this pattern can be related to the assembly process. A second one appears in the dark images, and shows bright arcs connecting corners along the vertical axis of the CCD. This feature appears in all CCDs exactly in the same position so our guess is that the pattern is due to electrical fields. Finally, and just in two devices, there is a spot with wavelength dependence whose origin could be the result of a defectous coating process.

  7. Proactive condition monitoring of low-speed machines

    CERN Document Server

    Stamboliska, Zhaklina; Moczko, Przemyslaw

    2015-01-01

    This book broadens readers’ understanding of proactive condition monitoring of low-speed machines in heavy industries. It focuses on why low-speed machines are different than others and how maintenance of these machines should be implemented with particular attention. The authors explain the best available monitoring techniques for various equipment and the principle of how to get proactive information from each technique. They further put forward possible strategies for application of FEM for detection of faults and technical assessment of machinery. Implementation phases are described and industrial case-studies of proactive condition monitoring are included. Proactive Condition Monitoring of Low-Speed Machines is an essential resource for engineers and technical managers across a range of industries as well as design engineers working in industrial product development. This book also: ·         Explains the practice of proactive condition monitoring and illustrates implementation phases ·   ...

  8. Image mosaic for one aerial reconnaissance CCD camera based on object straight edge nodes%利用目标直线边缘交点的某型航侦CCD相机图像拼接

    Institute of Scientific and Technical Information of China (English)

    张德新; 马广富; 邵晓巍

    2012-01-01

    针对某型航侦CCD相机图像序列之间的特殊变换关系,提出了一种基于目标直线边缘交点的图像拼接方法.该方法在将相机图像重叠区域分割为较小独立区域的基础上,首先使用Canny边缘检测算子提取各个区域中的边缘信息,并用Hough变换提取边缘中的直线边缘.其次通过提出一种依据直线极坐标参数的区域扩展和选择策略来选择包含完整目标的子图像区域,并提取该区域中目标直线边缘的交点.最终根据提取到的直线边缘交点坐标实现图像配准,且采用双线性插值法融合配准区域,实现了图像的无缝拼接.实际的飞行效果验证了该图像拼接方法的有效性.%An image mosaic method of object straight edge nodes was proposed by the unique transformation relation between the image sequences of one aerial reconnaissance CCD camera. In that scheme, overlap area of images were first segmented into smaller sub-images independently, and Canny edge detection operator was employed to extract the edge information from each single area, then straight edges from the obtained edge information were also derived by Hough transform. Moreover, a strategy of area expanding and selection was proposed to extract the straight edge nodes, and it was applied to keep the segment area containing an effective object. Finally, image registration was finished according to the obtained straight edge nodes, and seamless mosaic image could be achieved by bilinear interpolation method. The actual mosaic results are also presented to verify the effectives of the proposed image mosaic approach.

  9. 小卫星CCD相机MTF在轨测量与图像复原%On-orbit MTF estimation and restoration for CCD cameras of environment and disaster reduction small satellites (HJ 1A/1B)

    Institute of Scientific and Technical Information of China (English)

    杨贵军; 邢著荣; 黄文江; 王纪华

    2011-01-01

    Focusing on the CCD cameras of environment and disaster reduction small satellites (HJ1A/1B),an approach on the on-orbit measurement of modulation transfer function (MTF)to the imaging system was proposed. According to selecting the distinct edges among two homogeneous objects from images, the degraded images were processed with smooth filtering, curve fitting and the forward Fourier transform(FFT) of line spread function(LSF) to obtain the point spread function (PSF). After that, MTF corresponding to PSF can be obtained through FFT. Taking into account the noise of the complex constraint restoration method (CRM) without universality, the deconvolution restoration method in frequency domain was proposed, because it had the advantage that we neet not prove the parameters of sensor and atmosphere. Finally, analyzing and evaluating the restored image were carried out based on three factors: the feature value, definition and texture, respectively. The results show that the quality of HJ1A/1B image has been obviously improved, and achieved good restoration results.%基于调制传递函数的基本理论,针对环境与减灾小卫星光学相机,基于刃边法给出了一种在轨测量成像系统调制传递函数的方法.通过选取图像中均匀地物之间灰度变化明显的边缘,对有限采样点进行平滑滤波、曲线拟合和对线扩展函数(LSF)的傅里叶变换获得点扩展函数(PSF),提取调制传递函数(MTF)曲线,进而选取最优的MTF曲线.考虑到采用有约束复原方法时噪声统计、估计的复杂性和欠普适性,本方法通过频率域的去卷积进行复原处理,其优势在于不需要提供传感器、大气状况等参数.并对复原图像从统计特征、清晰度、纹理特征等3方面进行了定量分析和评价.结果表明:复原后的环境与减灾小卫星图像质量得到明显提高,收到良好的复原效果.

  10. CCD characterization and measurements automation

    Energy Technology Data Exchange (ETDEWEB)

    Kotov, I.V., E-mail: kotov@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States); Frank, J.; Kotov, A.I. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Kubanek, P. [Institute of Physics of the Academy of Sciences, Prague, CZ 18221 (Czech Republic); Image Processing Laboratory, Universidad de Valencia (Spain); O' Connor, P. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Prouza, M. [Institute of Physics of the Academy of Sciences, Prague, CZ 18221 (Czech Republic); Radeka, V.; Takacs, P. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2012-12-11

    Modern mosaic cameras have grown both in size and in number of sensors. The required volume of sensor testing and characterization has grown accordingly. For camera projects as large as the LSST, test automation becomes a necessity. A CCD testing and characterization laboratory was built and is in operation for the LSST project. Characterization of LSST study contract sensors has been performed. The characterization process and its automation are discussed, and results are presented. Our system automatically acquires images, populates a database with metadata information, and runs express analysis. This approach is illustrated on {sup 55}Fe data analysis. {sup 55}Fe data are used to measure gain, charge transfer efficiency and charge diffusion. Examples of express analysis results are presented and discussed.

  11. CCD digital radiography system

    Science.gov (United States)

    Wang, Yi; Kang, Xi; Li, Yuanjing; Cheng, Jianping; Hou, Yafei; Han, Haiwei

    2009-07-01

    Amorphous silicon flat-panel detector is the mainstream used in digital radiography (DR) system. In latest years, scintillation screen coupled with CCD DR is becoming more popular in hospital. Compared with traditional amorphous silicon DR, CCD-DR has better spatial resolution and has little radiation damage. It is inexpensive and can be operated easily. In this paper, A kind of CCD based DR system is developed. We describe the construction of the system, the system performances and experiment results.

  12. Binocular videogrammetric system for three-dimensional measurement in low-speed wind tunnel

    Science.gov (United States)

    Zhu, Ye; Gu, Yonggang; Zhai, Chao

    2014-11-01

    In order to avoid the defects of contact measurement, such as limited range, complex constructing and disability of 3-D parameter acquisition, we built a binocular videogrammetric system for measuring 3-D geometry parameters of wind tunnel test models, for instance, displacement, rotation angle and vibration, in low-speed wind tunnel. The system is based on the principles of close-range digital photogrammetry. As a non-contact system, it acquires parameters without interference in the experiments, and it has adjustable range and simple structure. It is worth mentioning that this is a Realtime measurement system, so that it can greatly compress the experiment period, furthermore, it is also able to provide some specific experiments with parameters for online adjustment. In this system, images are acquired through two industrial digital cameras and a PCI-E image acquisition card, and they are processed in a PC. The two cameras are triggered by signals come from a function signal generator, so that images of different cameras will have good temporal synchronization to ensure the accuracy of 3-D reconstruction. A two-step stereo calibration technique using planar pattern developed by Zhengyou Zhang is used to calibrate these cameras. Results of wind tunnel test indicate that the system can provide displacement accuracy better than 0.1% and rotation angle accuracy better than 0.1 degree, besides, the vibration frequency accuracy is superior to 0.1Hz in the low-frequency range.

  13. Low Speed PSP Testing in Production Wind Tunnels

    Science.gov (United States)

    Bell, James; Mehta, Rabi; Schairer, Ed; Hand, Larry; Nixon, David (Technical Monitor)

    1998-01-01

    The brightness signal from a pressure-sensitive paint varies inversely with absolute pressure. Consequently high signal-to-noise ratios are required to resolve aerodynamic pressure fields at low speeds, where the pressure variation around an object might only be a few percent of the mean pressure. This requirement is unavoidable, and implies that care must be taken to minimize noise sources present in the measurement. This paper discusses and compares the main noise sources in low speed PSP testing using the "classical" intensity-based single-luminophore technique. These are: temperature variation, model deformation, and lamp drift/paint degradation. Minimization of these error sources from the point of view of operation in production wind tunnels is discussed, with some examples from recent tests in NASA Ames facilities.

  14. Modeling violent reaction following low speed impact on confined explosives

    Science.gov (United States)

    Curtis, John Philip; Jones, Andrew; Hughes, Christopher; Reaugh, John

    2012-03-01

    To ensure the safe storage and deployment of explosives it is important to understand the mechanisms that give rise to ignition and reaction growth in low speed impacts. The High Explosive Response to Mechanical Stimulus (HERMES) material model, integrated in the Lagrangian code LSDYNA, has been developed to model the progress of the reaction after such an impact. The low speed impact characteristics of an HMX based formulation have been examined using the AWE Steven Test. Axisymmetric simulations of an HMX explosive in the AWE Steven Test have been performed. A sensitivity study included the influence of friction, mesh resolution, and confinement. By comparing the experimental and calculated results, key model parameters which determine the explosive's response in this configuration have been identified. The model qualitatively predicts the point of ignition within the vehicle. Future refinements are discussed.

  15. CCD BVI c observations of Cepheids

    Science.gov (United States)

    Berdnikov, L. N.; Kniazev, A. Yu.; Sefako, R.; Kravtsov, V. V.; Zhujko, S. V.

    2014-02-01

    In 2008-2013, we obtained 11333 CCD BVI c frames for 57 Cepheids from the General Catalogue of Variable Stars. We performed our observations with the 76-cm telescope of the South African Astronomical Observatory (SAAO, South Africa) and the 40-cm telescope of the Cerro Armazones Astronomical Observatory of the Universidad Católica del Norte (OCA, Chile) using the SBIG ST-10XME CCD camera. The tables of observations, the plots of light curves, and the current light elements are presented. Comparison of our light curves with those constructed from photoelectric observations shows that the differences between their mean magnitudes exceed 0ṃ05 in 20% of the cases. This suggests the necessity of performing CCD observations for all Cepheids.

  16. Low-speed flowfield characterization by infrared measurements of surface temperatures

    Science.gov (United States)

    Gartenberg, E.; Roberts, A. S., Jr.; Mcree, G. J.

    1989-01-01

    An experimental program was aimed at identifying areas in low speed aerodynamic research where infrared imaging systems can make significant contributions. Implementing a new technique, a long electrically heated wire was placed across a laminar jet. By measuring the temperature distribution along the wire with the IR imaging camera, the flow behavior was identified. Furthermore, using Nusselt number correlations, the velocity distribution could be deduced. The same approach was used to survey wakes behind cylinders in a wind-tunnel. This method is suited to investigate flows with position dependent velocities, e.g., boundary layers, confined flows, jets, wakes, and shear layers. It was found that the IR imaging camera cannot accurately track high gradient temperature fields. A correlation procedure was devised to account for this limitation. Other wind-tunnel experiments included tracking the development of the laminar boundary layer over a warmed flat plate by measuring the chordwise temperature distribution. This technique was applied also to the flow downstream from a rearward facing step. Finally, the IR imaging system was used to study boundary layer behavior over an airfoil at angles of attack from zero up to separation. The results were confirmed with tufts observable both visually and with the IR imaging camera.

  17. 9x15 Low Speed Wind Tunnel Improvements Update

    Science.gov (United States)

    Stephens, David

    2017-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn Research Center was built in 1969 in the return leg of the 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT). The 9x15 LSWT was designed for performance testing of VSTOL aircraft models, but with the addition of the current acoustic treatment in 1986 the tunnel been used principally for acoustic and performance testing of aircraft propulsion systems. The present document describes an anticipated acoustic upgrade to be completed in 2018.

  18. Boundary-layer predictions for small low-speed contractions

    Science.gov (United States)

    Mehta, Rabindra D.; Bell, James H.

    1989-01-01

    The present scheme for the prediction of boundary-layer development in small, low-speed wind tunnel contraction sections proceeds by calculating the wall pressure distributions, and hence the wall velocity distributions, by means of a three-dimensional potential-flow method. For the family of contractions presently treated, the assumption of a laminar boundary layer appears to be justified; the measured boundary layer momentum thicknesses at the exit of the four contractions were found to lie within 10 percent of predicted values.

  19. Evaluating intensified camera systems

    Energy Technology Data Exchange (ETDEWEB)

    S. A. Baker

    2000-07-01

    This paper describes image evaluation techniques used to standardize camera system characterizations. Key areas of performance include resolution, noise, and sensitivity. This team has developed a set of analysis tools, in the form of image processing software used to evaluate camera calibration data, to aid an experimenter in measuring a set of camera performance metrics. These performance metrics identify capabilities and limitations of the camera system, while establishing a means for comparing camera systems. Analysis software is used to evaluate digital camera images recorded with charge-coupled device (CCD) cameras. Several types of intensified camera systems are used in the high-speed imaging field. Electro-optical components are used to provide precise shuttering or optical gain for a camera system. These components including microchannel plate or proximity focused diode image intensifiers, electro-static image tubes, or electron-bombarded CCDs affect system performance. It is important to quantify camera system performance in order to qualify a system as meeting experimental requirements. The camera evaluation tool is designed to provide side-by-side camera comparison and system modeling information.

  20. Handling Qualities of Large Rotorcraft in Hover and Low Speed

    Science.gov (United States)

    Malpica, Carlos; Theodore, Colin R.; Lawrence , Ben; Blanken, Chris L.

    2015-01-01

    According to a number of system studies, large capacity advanced rotorcraft with a capability of high cruise speeds (approx.350 mph) as well as vertical and/or short take-off and landing (V/STOL) flight could alleviate anticipated air transportation capacity issues by making use of non-primary runways, taxiways, and aprons. These advanced aircraft pose a number of design challenges, as well as unknown issues in the flight control and handling qualities domains. A series of piloted simulation experiments have been conducted on the NASA Ames Research Center Vertical Motion Simulator (VMS) in recent years to systematically investigate the fundamental flight control and handling qualities issues associated with the characteristics of large rotorcraft, including tiltrotors, in hover and low-speed maneuvering.

  1. 9x15 Low Speed Wind Tunnel Acoustic Improvements

    Science.gov (United States)

    Stark, David; Stephens, David

    2016-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn Research Center was built in 1969 in the return leg of the 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT). The 8x6 SWT was completed in 1949 and acoustically treated to mitigate community noise issues in 1950. This treatment included the addition of a large muffler downstream of the 8x6 SWT test section and diffuser. The 9x15 LSWT was designed for performance testing of VSTOL aircraft models, but with the addition of the current acoustic treatment in 1986 the tunnel has been used principally for acoustic and performance testing of aircraft propulsions systems. The present document describes an anticipated acoustic upgrade to be completed in 2017.

  2. DepAstroCCD an original astrometric tool

    Directory of Open Access Journals (Sweden)

    Stojanović I.

    2006-01-01

    Full Text Available A complex software for preparation and treatment of astro photographic plates and double-star observations recorded with CCD cameras is developed. The preparation interface contains a catalogue base for the choice of observation objects and an interface for bringing into accordance the telescope and CCD camera performance with the assumptions of the postprocessor interface. The processing is based on the original development of image gradient removing software and classical FFT method and autocorrelation. The software has been tested on several theoretical and real images of double stars.

  3. Fast PSP measurements of wall-pressure fluctuation in low-speed flows: improvements using proper orthogonal decomposition

    Science.gov (United States)

    Peng, Di; Wang, Shaofei; Liu, Yingzheng

    2016-04-01

    Fast pressure-sensitive paint (PSP) is very useful in flow diagnostics due to its fast response and high spatial resolution, but its applications in low-speed flows are usually challenging due to limitations of paint's pressure sensitivity and the capability of high-speed imagers. The poor signal-to-noise ratio in low-speed cases makes it very difficult to extract useful information from the PSP data. In this study, unsteady PSP measurements were made on a flat plate behind a cylinder in a low-speed wind tunnel (flow speed from 10 to 17 m/s). Pressure fluctuations (Δ P) on the plate caused by vortex-plate interaction were recorded continuously by fast PSP (using a high-speed camera) and a microphone array. Power spectrum of pressure fluctuations and phase-averaged Δ P obtained from PSP and microphone were compared, showing good agreement in general. Proper orthogonal decomposition (POD) was used to reduce noise in PSP data and extract the dominant pressure features. The PSP results reconstructed from selected POD modes were then compared to the pressure data obtained simultaneously with microphone sensors. Based on the comparison of both instantaneous Δ P and root-mean-square of Δ P, it was confirmed that POD analysis could effectively remove noise while preserving the instantaneous pressure information with good fidelity, especially for flows with strong periodicity. This technique extends the application range of fast PSP and can be a powerful tool for fundamental fluid mechanics research at low speed.

  4. Low-speed impact cratering in loose granular media

    Science.gov (United States)

    Durian, Douglas

    2005-03-01

    In this talk I shall describe the penetration of projectiles dropped into noncohesive granular media, and how the results vary with the properties of both the projectile and the medium. In contrast to wide assumption, the penetration depth and crater diameter represent two distinct length scales. The diameter scales as the 1/4 power of projectile energy, but curiously the depth is not a simple function of either the projectile energy or momentum at impact. Rather, it scales as the 1/2 power of density, the 2/3 power of projectile diameter, and the 1/3 power of total drop distance. This same result also holds for cylinders with a variety of tips, and so is not an accident of projectile shape. It is crucial to understand the penetration depth because it is directly related to the mechanics of impact, namely the average stopping force acting between projectile and medium. In addition to this discussion, I shall also present new data on the dynamics of impact. All experiments were constructed and carried out at UCLA by undergraduate physics majors: Jun Uehara, Katie Newhall, Chris Santore, and Mike Ambroso.[1] J.S. Uehara, M.A. Ambroso, R.P. Ojha, and D.J. Durian, ``Low-Speed Impact Craters in Loose Granular Media,'' Phys. Rev. Lett. 90, 194301 (2003).[2] K.A. Newhall and D.J. Durian, ``Projectile-shape dependence of impact craters in loose granular media,'' Phys. Rev. E 68, 06030R (2003).[3] M.A. Ambroso, C.R. Santore, A.R. Abate, and D.J. Durian, ``Penetration depth for shallow impact cratering,'' cond-mat/0411231 (2004).

  5. Measurements of 42 Wide CPM Pairs with a CCD

    Science.gov (United States)

    Harshaw, Richard

    2015-11-01

    This paper addresses the use of a Skyris 618C color CCD camera as a means of obtaining data for analysis in the measurement of wide common proper motion stars. The equipment setup is described and data collection procedure outlined. Results of the measures of 42 CPM stars are presented, showing the Skyris is a reliable device for the measurement of double stars.

  6. Low Speed Motion Optimization of Space Manipulator Based on Gradient Projection Method

    Directory of Open Access Journals (Sweden)

    Peng Junjie

    2015-01-01

    Full Text Available Low-speed crawling phenomenon may occur when space manipulators run at a low speed, which may bring big problem for manipulation work. A kind of low-speed optimization algorithm based on gradient projection method is pro-posed in this paper. The designing of continuous balanced proportional factor can effectively reduce the quantitative differences between the homogeneous solution and the special solution, avoiding the joint velocities oscillations. The low-speed crawling problem can be effectively improved by appropriate increase of joint velocities. And the effectiveness and correctness of the optimization algorithm are confirmed by the simulation.

  7. Stroboscope Based Synchronization of Full Frame CCD Sensors

    Directory of Open Access Journals (Sweden)

    Liang Shen

    2017-04-01

    Full Text Available The key obstacle to the use of consumer cameras in computer vision and computer graphics applications is the lack of synchronization hardware. We present a stroboscope based synchronization approach for the charge-coupled device (CCD consumer cameras. The synchronization is realized by first aligning the frames from different video sequences based on the smear dots of the stroboscope, and then matching the sequences using a hidden Markov model. Compared with current synchronized capture equipment, the proposed approach greatly reduces the cost by using inexpensive CCD cameras and one stroboscope. The results show that our method could reach a high accuracy much better than the frame-level synchronization of traditional software methods.

  8. Characterization of the Series 1000 Camera System

    Energy Technology Data Exchange (ETDEWEB)

    Kimbrough, J; Moody, J; Bell, P; Landen, O

    2004-04-07

    The National Ignition Facility requires a compact network addressable scientific grade CCD camera for use in diagnostics ranging from streak cameras to gated x-ray imaging cameras. Due to the limited space inside the diagnostic, an analog and digital input/output option in the camera controller permits control of both the camera and the diagnostic by a single Ethernet link. The system consists of a Spectral Instruments Series 1000 camera, a PC104+ controller, and power supply. The 4k by 4k CCD camera has a dynamic range of 70 dB with less than 14 electron read noise at a 1MHz readout rate. The PC104+ controller includes 16 analog inputs, 4 analog outputs and 16 digital input/output lines for interfacing to diagnostic instrumentation. A description of the system and performance characterization is reported.

  9. Accurate measurement of streamwise vortices in low speed aerodynamic flows

    Science.gov (United States)

    Waldman, Rye M.; Kudo, Jun; Breuer, Kenneth S.

    2010-11-01

    Low Reynolds number experiments with flapping animals (such as bats and small birds) are of current interest in understanding biological flight mechanics, and due to their application to Micro Air Vehicles (MAVs) which operate in a similar parameter space. Previous PIV wake measurements have described the structures left by bats and birds, and provided insight to the time history of their aerodynamic force generation; however, these studies have faced difficulty drawing quantitative conclusions due to significant experimental challenges associated with the highly three-dimensional and unsteady nature of the flows, and the low wake velocities associated with lifting bodies that only weigh a few grams. This requires the high-speed resolution of small flow features in a large field of view using limited laser energy and finite camera resolution. Cross-stream measurements are further complicated by the high out-of-plane flow which requires thick laser sheets and short interframe times. To quantify and address these challenges we present data from a model study on the wake behind a fixed wing at conditions comparable to those found in biological flight. We present a detailed analysis of the PIV wake measurements, discuss the criteria necessary for accurate measurements, and present a new dual-plane PIV configuration to resolve these issues.

  10. Experimental Research on the SizeMeasurement of the High Temperature ForgingBased on Multicolor CCD Technology

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    In order to determine the size measurement accuracy of the high temperature forging's multicolor CCD image by using computerprograms, this paper obtained the high temperature forging's CCD image by multicolor CCD camera and its fact size by thevernier caliper on the forging field, and then measured the size of the high temperature forging from its CCD image, compared thesize from the CCD image and the size from the vernier caliper, the result shows that the measurement accuracy satisfied theindustrial production.

  11. A CCD Spectrometer for One Dollar

    Science.gov (United States)

    Beaver, J.; Robert, D.

    2011-09-01

    We describe preliminary tests on a very low-cost system for obtaining stellar spectra for instructional use in an introductory astronomy laboratory. CCD imaging with small telescopes is now commonplace and relatively inexpensive. Giving students direct experience taking stellar spectra, however, is much more difficult, and the equipment can easily be out of reach for smaller institutions, especially if one wants to give the experience to large numbers of students. We have performed preliminary tests on an extremely low-cost (about $1.00) objective grating that can be coupled with an existing CCD camera or commercial digital single-lens reflex (DSLR) camera and a small telescope typical of introductory astronomy labs. With this equipment we believe it is possible for introductory astronomy students to take stellar spectra that are of high enough quality to distinguish between many MK spectral classes, or to determine standard B and V magnitudes. We present observational tests of this objective grating used on an 8" Schmidt-Cassegrain with a low-end, consumer DSLR camera. Some low-cost strategies for reducing the raw data are compared, with an eye toward projects ranging from individual undergraduate research projects to use by many students in a non-majors introductory astronomy lab. Toward this end we compare various trade offs between complexity of the observing and data reduction processes and the usefulness of the final results. We also describe some undergraduate astronomy education projects that this system could potentially be used for. Some of these projects could involve data-sharing collaborations between students at different institutions.

  12. Intelligent Camera for Surface Defect Inspection

    Institute of Scientific and Technical Information of China (English)

    CHENG Wan-sheng; ZHAO Jie; WANG Ke-cheng

    2007-01-01

    An intelligent camera for surface defect inspection is presented which can pre-process the surface image of a rolled strip and pick defective areas out at a spead of 1600 meters per minute. The camera is made up of a high speed line CCD, a 60Mb/s CCD digitizer with correlated double sampling function, and a field programmable gate array(FPGA), which can quickly distinguish defective areas using a perceptron embedded in FPGA thus the data to be further processed would dramatically be reduced. Some experiments show that the camera can meet high producing speed, and reduce cost and complexity of automation surface inspection systems.

  13. Performance Improvement of Servo Machine Low Speed Operation Using RBFN Disturbance Observer

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2004-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The typical speed estimation scheme in most servo system for low speed operation is sensitive to the variation of machine parameters, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Networks (RBFN) is applied. The effectiveness of the proposed inertia estimation method is verified by experiments. It is concluded that the speed control performance in the low speed region is improved with the proposed...

  14. Thermal management for CCD peformance of one space telescope

    Science.gov (United States)

    Yang, Wengang; Wang, Yinghao; Feng, Liangjie; Wang, Chenjie; Ren, Guorui; Wang, Wei; Li, Chuang; Gao, Wei; Fan, Xuewu

    2012-10-01

    A space telescope containing two CCD cameras is being built for scientific observation. The CCD detectors need to operate at a temperature below -65°C in order to avoid unacceptable dark current. This cooling is achieved through detailed thermal design which minimizes the parasitic load to 2K×4K array with 13.5 micron pixels and cools this detector with a combination of thermo electric cooler(TEC). This paper will describe detailed thermal design necessary to maintain the CCD at its cold operating temperature while providing the means to reject the heat generated by the TECs. It will focus on optimized techniques developed to manage parasitic loads including material selection, surface finishes and thermal insulation. The paper will also address analytical techniques developed to characterize TEC performance. Finally, analysis results have been shown the temperature of key parts.

  15. A quantitative striping removal algorithm for HY- 1 CCD data

    Institute of Scientific and Technical Information of China (English)

    孙凌; 唐军武; 张杰

    2002-01-01

    -- Striping is a common phenomenon in remote sensing imagery acquired by most spaceborne and airborne multispectral sensors. In contrast to the destriping of the images of optoelectronic mechanical scanners, fewer work has been done for push-broom CCD images. Based on the characteristics of HY-1 push-broom multispectral CCD camera and its prelaunch radiometric calibration results, the striping features are analyzed and a quantitative striping removal algorithm is proposed. The algorithm is to obtain the inter-detector equalization curves to reflect the differences between detectors by statistic analysis of the satellite imagery data set, and image stripes arising from the nonuniformity of the detectors of the CCD array can be removed using the estimated equalization curves. The preliminary results show that this method can effectively remove the stripes and preserve the radiometric accuracy of the raw data at the same time.

  16. Method for eliminating artifacts in CCD imagers

    Science.gov (United States)

    Turko, B. T.; Yates, G. J.

    1990-06-01

    An electronic method for eliminating artifacts in a video camera employing a charge coupled device (CCD) as an image sensor is presented. The method comprises the step of initializing the camera prior to normal readout. The method includes a first dump cycle period for transferring radiation generated charge into the horizontal register. This occurs while the decaying image on the phosphor being imaged is being integrated in the photosites, and a second dump cycle period, occurring after the phosphor image has decayed, for rapidly dumping unwanted smear charge which has been generated in the vertical registers. Image charge is then transferred from the photosites and to the vertical registers and readout in conventional fashion. The inventive method allows the video camera to be used in environments having high ionizing radiation content, and to capture images of events of very short duration and occurring either within or outside the normal visual wavelength spectrum. Resultant images are free from ghost, smear, and smear phenomena caused by insufficient opacity of the registers, and are also free from random damage caused by ionization charges which exceed the charge limit capacity of the photosites.

  17. Robust and Stable Disturbance Observer of Servo System for Low-Speed Operation

    DEFF Research Database (Denmark)

    Lee, Kyo Beum; Blaabjerg, Frede

    2007-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low-speed operation is sensitive to the variation of machine parameter, especially the moment of inertia. To esti......A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low-speed operation is sensitive to the variation of machine parameter, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable...

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

    Science.gov (United States)

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

    2015-12-01

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

  19. CCD Astrophotography High-Quality Imaging from the Suburbs

    CERN Document Server

    Stuart, Adam

    2006-01-01

    This is a reference book for amateur astronomers who have become interested in CCD imaging. Those glorious astronomical images found in astronomy magazines might seem out of reach to newcomers to CCD imaging, but this is not the case. Great pictures are attainable with modest equipment. Adam Stuart’s many beautiful images, reproduced in this book, attest to the quality of – initially – a beginner’s efforts. Chilled-chip astronomical CCD-cameras and software are also wonderful tools for cutting through seemingly impenetrable light-pollution. CCD Astrophotography from the Suburbs describes one man’s successful approach to the problem of getting high-quality astronomical images under some of the most light-polluted conditions. Here is a complete and thoroughly tested program that will help every CCD-beginner to work towards digital imaging of the highest quality. It is equally useful to astronomers who have perfect observing conditions, as to those who have to observe from light-polluted city skies.

  20. Scientific CCD characterisation at Universidad Complutense LICA Laboratory

    Science.gov (United States)

    Tulloch, S.; Gil de Paz, A.; Gallego, J.; Zamorano, J.; Tapia, Carlos

    2012-07-01

    A CCD test-bench has been built at the Universidad Complutensés LICA laboratory. It is initially intended for commissioning of the MEGARA1 (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) instrument but can be considered as a general purpose scientific CCD test-bench. The test-bench uses an incandescent broad-band light source in combination with a monochromator and two filter wheels to provide programmable narrow-band illumination across the visible band. Light from the monochromator can be directed to an integrating sphere for flat-field measurements or sent via a small aperture directly onto the CCD under test for high accuracy diode-mode quantum efficiency measurements. Point spread function measurements can also be performed by interposing additional optics between sphere and the CCD under test. The whole system is under LabView control via a clickable GUI. Automated measurement scans of quantum efficiency can be performed requiring only that the user replace the CCD under test with a calibrated photodiode after each measurement run. A 20cm diameter cryostat with a 10cm window and Brooks Polycold PCC closed-cycle cooler also form part of the test-bench. This cryostat is large enough to accommodate almost all scientific CCD formats has initially been used to house an E2V CCD230 in order to fully prove the test-bench functionality. This device is read-out using an Astronomical Research Camera controller connected to the UKATC's UCAM data acquisition system.

  1. Mars Science Laboratory Engineering Cameras

    Science.gov (United States)

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

    2012-01-01

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

  2. A Bridge Deflection Monitoring System Based on CCD

    Directory of Open Access Journals (Sweden)

    Baohua Shan

    2016-01-01

    Full Text Available For long-term monitoring of the midspan deflection of Songjiazhuang cloverleaf junction on 309 national roads in Zibo city, this paper proposes Zhang’s calibration-based DIC deflection monitoring method. CCD cameras are used to track the change of targets’ position, Zhang’s calibration algorithm is introduced to acquire the intrinsic and extrinsic parameters of CCD cameras, and the DIC method is combined with Zhang’s calibration algorithm to measure bridge deflection. The comparative test between Zhang’s calibration and scale calibration is conducted in lab, and experimental results indicate that the proposed method has higher precision. According to the deflection monitoring scheme, the deflection monitoring software for Songjiazhuang cloverleaf junction is developed by MATLAB, and a 4-channel CCD deflection monitoring system for Songjiazhuang cloverleaf junction is integrated in this paper. This deflection monitoring system includes functions such as image preview, simultaneous collection, camera calibration, deflection display, and data storage. In situ deflection curves show a consistent trend; this suggests that the proposed method is reliable and is suitable for the long-term monitoring of bridge deflection.

  3. Parallel optical coherence tomography using a CCD camera

    Institute of Scientific and Technical Information of China (English)

    Junle Qu(屈军乐); Ravi S.Jonnal; Donald T. Miller

    2004-01-01

    Parallel optical coherence tomography is demonstrated using a 12-bit scientific-grade charge-coupled device array.A superluminescent diode in combination with a free-space Michelson interferometer was employed to achieve 10-μm axial resolution and 1.1-μm transverse resolution on a 902×575 μm2 field of view.We imaged a test mirror and bovine retinal tissue using a four-step phase shift method.

  4. Neutron counting with cameras

    Energy Technology Data Exchange (ETDEWEB)

    Van Esch, Patrick; Crisanti, Marta; Mutti, Paolo [Institut Laue Langevin, Grenoble (France)

    2015-07-01

    A research project is presented in which we aim at counting individual neutrons with CCD-like cameras. We explore theoretically a technique that allows us to use imaging detectors as counting detectors at lower counting rates, and transits smoothly to continuous imaging at higher counting rates. As such, the hope is to combine the good background rejection properties of standard neutron counting detectors with the absence of dead time of integrating neutron imaging cameras as well as their very good spatial resolution. Compared to Xray detection, the essence of thermal neutron detection is the nuclear conversion reaction. The released energies involved are of the order of a few MeV, while X-ray detection releases energies of the order of the photon energy, which is in the 10 KeV range. Thanks to advances in camera technology which have resulted in increased quantum efficiency, lower noise, as well as increased frame rate up to 100 fps for CMOS-type cameras, this more than 100-fold higher available detection energy implies that the individual neutron detection light signal can be significantly above the noise level, as such allowing for discrimination and individual counting, which is hard to achieve with X-rays. The time scale of CMOS-type cameras doesn't allow one to consider time-of-flight measurements, but kinetic experiments in the 10 ms range are possible. The theory is next confronted to the first experimental results. (authors)

  5. The Dark Energy Camera

    CERN Document Server

    Flaugher, B; Honscheid, K; Abbott, T M C; Alvarez, O; Angstadt, R; Annis, J T; Antonik, M; Ballester, O; Beaufore, L; Bernstein, G M; Bernstein, R A; Bigelow, B; Bonati, M; Boprie, D; Brooks, D; Buckley-Geer, E J; Campa, J; Cardiel-Sas, L; Castander, F J; Castilla, J; Cease, H; Cela-Ruiz, J M; Chappa, S; Chi, E; Cooper, C; da Costa, L N; Dede, E; Derylo, G; DePoy, D L; de Vicente, J; Doel, P; Drlica-Wagner, A; Eiting, J; Elliott, A E; Emes, J; Estrada, J; Neto, A Fausti; Finley, D A; Flores, R; Frieman, J; Gerdes, D; Gladders, M D; Gregory, B; Gutierrez, G R; Hao, J; Holland, S E; Holm, S; Huffman, D; Jackson, C; James, D J; Jonas, M; Karcher, A; Karliner, I; Kent, S; Kessler, R; Kozlovsky, M; Kron, R G; Kubik, D; Kuehn, K; Kuhlmann, S; Kuk, K; Lahav, O; Lathrop, A; Lee, J; Levi, M E; Lewis, P; Li, T S; Mandrichenko, I; Marshall, J L; Martinez, G; Merritt, K W; Miquel, R; Munoz, F; Neilsen, E H; Nichol, R C; Nord, B; Ogando, R; Olsen, J; Palio, N; Patton, K; Peoples, J; Plazas, A A; Rauch, J; Reil, K; Rheault, J -P; Roe, N A; Rogers, H; Roodman, A; Sanchez, E; Scarpine, V; Schindler, R H; Schmidt, R; Schmitt, R; Schubnell, M; Schultz, K; Schurter, P; Scott, L; Serrano, S; Shaw, T M; Smith, R C; Soares-Santos, M; Stefanik, A; Stuermer, W; Suchyta, E; Sypniewski, A; Tarle, G; Thaler, J; Tighe, R; Tran, C; Tucker, D; Walker, A R; Wang, G; Watson, M; Weaverdyck, C; Wester, W; Woods, R; Yanny, B

    2015-01-01

    The Dark Energy Camera is a new imager with a 2.2-degree diameter field of view mounted at the prime focus of the Victor M. Blanco 4-meter telescope on Cerro Tololo near La Serena, Chile. The camera was designed and constructed by the Dark Energy Survey Collaboration, and meets or exceeds the stringent requirements designed for the wide-field and supernova surveys for which the collaboration uses it. The camera consists of a five element optical corrector, seven filters, a shutter with a 60 cm aperture, and a CCD focal plane of 250 micron thick fully-depleted CCDs cooled inside a vacuum Dewar. The 570 Mpixel focal plane comprises 62 2kx4k CCDs for imaging and 12 2kx2k CCDs for guiding and focus. The CCDs have 15 microns x15 microns pixels with a plate scale of 0.263 arc sec per pixel. A hexapod system provides state-of-the-art focus and alignment capability. The camera is read out in 20 seconds with 6-9 electrons readout noise. This paper provides a technical description of the camera's engineering, construct...

  6. The Dark Energy Camera

    Energy Technology Data Exchange (ETDEWEB)

    Flaugher, B. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States). et al.

    2015-04-11

    The Dark Energy Camera is a new imager with a 2.2-degree diameter field of view mounted at the prime focus of the Victor M. Blanco 4-meter telescope on Cerro Tololo near La Serena, Chile. The camera was designed and constructed by the Dark Energy Survey Collaboration, and meets or exceeds the stringent requirements designed for the wide-field and supernova surveys for which the collaboration uses it. The camera consists of a five element optical corrector, seven filters, a shutter with a 60 cm aperture, and a CCD focal plane of 250-μm thick fully depleted CCDs cooled inside a vacuum Dewar. The 570 Mpixel focal plane comprises 62 2k x 4k CCDs for imaging and 12 2k x 2k CCDs for guiding and focus. The CCDs have 15μm x 15μm pixels with a plate scale of 0.263" per pixel. A hexapod system provides state-of-the-art focus and alignment capability. The camera is read out in 20 seconds with 6-9 electrons readout noise. This paper provides a technical description of the camera's engineering, construction, installation, and current status.

  7. Formation and evolution of a hairpin vortex induced by subharmonic sinuous low-speed streaks

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Dong, Gang; Lu, Ziheng, E-mail: dgvehicle@yahoo.com [State Key Laboratory of Transient Physics, Nanjing University of Science and Technology, Nanjing, 210094, Jiangsu Province, People’s Republic of China (China)

    2014-10-01

    In this paper, a process of the formation and evolution of hairpin vortices, which originated from the interaction between the spanwise-aligned low-speed streaks with a subharmonic sinuous (SS) oscillation mode, is studied using a direct numerical simulation method in a small periodic local region of an incompressible plane channel flow. The initial artificial perturbations are used to excite the SS-mode oscillation of two spanwise-aligned low-speed streaks in such a flow. A new mechanism of formation and decay of the hairpin vortices is proposed in which the shear layer induced by the spanwise collision and merging between the low-speed streaks is emphasized. Our results show that the streamwise vortices can be induced by the SS-mode streaks and then developed into an X-like pattern at the initial stage due to the mutual induction effect. The X-like vortices further enhance the spanwise oscillation and lift-up of the two streaks that thus lead to the spanwise collision and merging of the low-speed streaks and produce a low-speed region in high-speed fluid. The strong shear layer between the high- and low-speed fluids gives rise to the spanwise vorticity that connects the X-like streamwise vortices and forms the Λ-like vortex. Once the low-speed region entirely enters the high-speed fluid, the shear layer shows the ring shape and results in the transition from a Λ-like vortex to Ω-like one. After that, the viscous diffusion of the low-speed region in the high-speed fluid leads to the decay of the Ω-like vortex; the collision and merging of the low-speed streaks simultaneously reoccur upstream and give birth to a secondary Λ-like vortex, which exhibits behavior that is nearly similar with that of the primary one. Although the hairpin vortex packet is not observed in the present plane channel flow, the regeneration of the hairpin vortex suggests that this type of vortical structure plays an important role in the wall-bounded flow. (paper)

  8. Optimization of precision localization microscopy using CMOS camera technology

    Science.gov (United States)

    Fullerton, Stephanie; Bennett, Keith; Toda, Eiji; Takahashi, Teruo

    2012-02-01

    Light microscopy imaging is being transformed by the application of computational methods that permit the detection of spatial features below the optical diffraction limit. Successful localization microscopy (STORM, dSTORM, PALM, PhILM, etc.) relies on the precise position detection of fluorescence emitted by single molecules using highly sensitive cameras with rapid acquisition speeds. Electron multiplying CCD (EM-CCD) cameras are the current standard detector for these applications. Here, we challenge the notion that EM-CCD cameras are the best choice for precision localization microscopy and demonstrate, through simulated and experimental data, that certain CMOS detector technology achieves better localization precision of single molecule fluorophores. It is well-established that localization precision is limited by system noise. Our findings show that the two overlooked noise sources relevant for precision localization microscopy are the shot noise of the background light in the sample and the excess noise from electron multiplication in EM-CCD cameras. At low light conditions (CCD cameras are the preferred detector. However, in practical applications, optical background noise is significant, creating conditions where CMOS performs better than EM-CCD. Furthermore, the excess noise of EM-CCD is equivalent to reducing the information content of each photon detected which, in localization microscopy, reduces the precision of the localization. Thus, new CMOS technology with 100fps, super resolution precision localization microscopy.

  9. Waveless ships in the low speed limit: Results for multi-cornered hulls

    CERN Document Server

    Trinh, Philippe H

    2015-01-01

    In the low-speed limit, a blunt ship modeled as two-dimensional semi-infinite body with a single corner can never be made waveless. This was the conclusion of the previous part of our work in Trinh et al. (2011), which focused on the Dagan & Tulin (1972) model of ship waves in the low speed limit. In this accompanying paper, we continue our investigations with the study of more general, piecewise-linear, or multi-cornered ships. The low-speed or low-Froude limit, coupled with techniques in exponential asymptotics allows us to derive explicit formulae relating the geometry of the hull to the form of the waves. Configurations with closely spaced corners present a non-trivial extension of the theory, and we present the general methodology for their study. Lastly, numerical computations of the nonlinear ship-wave problem are presented in order to confirm the analytical predictions.

  10. A Very Low-Speed Sensorless Induction Motor Drive with Online Stator Resistance identification scheme

    Directory of Open Access Journals (Sweden)

    M. Zaky

    2008-03-01

    Full Text Available Recently, speed sensorless control of induction motor drives received great attention to avoid the different problems associated with direct speed sensors. However, low speed operation with robustness against parameter variations remains an area of research for sensorless systems. Stator resistance is of greatest importance for good operation of speed sensorless systems in low speed region. In this paper, a sliding mode current observer for an induction motor is presented. An estimation algorithm based on this observer in conjunction with Popov's hyper-stability theory is proposed to calculate the speed and stator resistance independently. The proposed speed observer with parallel stator resistance identification is firstly verified by simulation. Experimental results are included as well to demonstrate the good performance of the proposed observer and estimation algorithms at low speed.

  11. CCD data reductions at ESO

    Science.gov (United States)

    Grosbol, Preben

    The image-processing and data-reduction functions of the IHAP and MIDAS software packages developed at ESO for CCD astronomy are briefly reviewed. IHAP and MIDAS perform the same basic operations on HP 1000 and VAX computers, respectively, and MIDAS is currently being modified to run in the UNIX operating system as well as in VAX VMS. Consideration is given to the special properties of CCD data, the removal of gross errors (due to bad pixels and cosmic-ray events), photometric correction for dark current and sensitivity variations, digital filtering and Fourier transforms, detection and classification algorithms for direct imaging, surface photometry of extended objects, function fitting, and image deconvolution.

  12. Low-speed Aerodynamic Investigations of a Hybrid Wing Body Configuration

    Science.gov (United States)

    Vicroy, Dan D.; Gatlin, Gregory M.; Jenkins, Luther N.; Murphy, Patrick C.; Carter, Melissa B.

    2014-01-01

    Two low-speed static wind tunnel tests and a water tunnel static and dynamic forced-motion test have been conducted on a hybrid wing-body (HWB) twinjet configuration. These tests, in addition to computational fluid dynamics (CFD) analysis, have provided a comprehensive dataset of the low-speed aerodynamic characteristics of this nonproprietary configuration. In addition to force and moment measurements, the tests included surface pressures, flow visualization, and off-body particle image velocimetry measurements. This paper will summarize the results of these tests and highlight the data that is available for code comparison or additional analysis.

  13. PAU camera: detectors characterization

    Science.gov (United States)

    Casas, Ricard; Ballester, Otger; Cardiel-Sas, Laia; Castilla, Javier; Jiménez, Jorge; Maiorino, Marino; Pío, Cristóbal; Sevilla, Ignacio; de Vicente, Juan

    2012-07-01

    The PAU Camera (PAUCam) [1,2] is a wide field camera that will be mounted at the corrected prime focus of the William Herschel Telescope (Observatorio del Roque de los Muchachos, Canary Islands, Spain) in the next months. The focal plane of PAUCam is composed by a mosaic of 18 CCD detectors of 2,048 x 4,176 pixels each one with a pixel size of 15 microns, manufactured by Hamamatsu Photonics K. K. This mosaic covers a field of view (FoV) of 60 arcmin (minutes of arc), 40 of them are unvignetted. The behaviour of these 18 devices, plus four spares, and their electronic response should be characterized and optimized for the use in PAUCam. This job is being carried out in the laboratories of the ICE/IFAE and the CIEMAT. The electronic optimization of the CCD detectors is being carried out by means of an OG (Output Gate) scan and maximizing it CTE (Charge Transfer Efficiency) while the read-out noise is minimized. The device characterization itself is obtained with different tests. The photon transfer curve (PTC) that allows to obtain the electronic gain, the linearity vs. light stimulus, the full-well capacity and the cosmetic defects. The read-out noise, the dark current, the stability vs. temperature and the light remanence.

  14. Inspection of calandria front area of Wolsung NPP using technique of mapping thermal infrared image into CCD image

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Kim, Chang Hoi; Seo, Yong Chil; Choi, Young Soo; Kim, Seung Ho [Advance Robotics Teams, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2002-11-15

    This paper describes the enhanced inspection performance of a thermal infrared camera for monitoring abnormal conditions of calandria reactor area of Wolsung nuclear power plant. Thermal infrared camera have poor image qualities compared to commercial CCD cameras, as in contrast, brightness, and resolution. To compensate the poor image quality problems associated with the thermal infrared camera, the technique of mapping thermal infrared image into real ccd image is proposed. The mobile robot KAEROT/m2, loaded with sensor head system at the mast, is entered to monitor leakage of heavy water and thermal abnormality of the calandria reactor area in overhaul period. The sensor head system is composed of thermal infrared camera and ccd camera in parallel. When thermal abnormality on observation points and areas of calandria reactor area is occurred, unusual hot image taken from thermal infrared camera is superimposed on real CCD image. In this inspection experiment, more accurate positions of thermal abnormalities on calandria reactor area can be estimated by using technique of mapping thermal infrared image into CCD image, which include characters arranged in MPOQ order.

  15. Electronic cameras for low-light microscopy.

    Science.gov (United States)

    Rasnik, Ivan; French, Todd; Jacobson, Ken; Berland, Keith

    2013-01-01

    This chapter introduces to electronic cameras, discusses the various parameters considered for evaluating their performance, and describes some of the key features of different camera formats. The chapter also presents the basic understanding of functioning of the electronic cameras and how these properties can be exploited to optimize image quality under low-light conditions. Although there are many types of cameras available for microscopy, the most reliable type is the charge-coupled device (CCD) camera, which remains preferred for high-performance systems. If time resolution and frame rate are of no concern, slow-scan CCDs certainly offer the best available performance, both in terms of the signal-to-noise ratio and their spatial resolution. Slow-scan cameras are thus the first choice for experiments using fixed specimens such as measurements using immune fluorescence and fluorescence in situ hybridization. However, if video rate imaging is required, one need not evaluate slow-scan CCD cameras. A very basic video CCD may suffice if samples are heavily labeled or are not perturbed by high intensity illumination. When video rate imaging is required for very dim specimens, the electron multiplying CCD camera is probably the most appropriate at this technological stage. Intensified CCDs provide a unique tool for applications in which high-speed gating is required. The variable integration time video cameras are very attractive options if one needs to acquire images at video rate acquisition, as well as with longer integration times for less bright samples. This flexibility can facilitate many diverse applications with highly varied light levels.

  16. 40 CFR 205.54-1 - Low speed sound emission test procedures.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Low speed sound emission test procedures. 205.54-1 Section 205.54-1 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... example, temperature, humidity, and barometric pressure). (ii) Proper signal levels, terminat-ing...

  17. Experimental Testing of a Generic Submarine Model in the DSTO Low Speed Wind Tunnel. Phase 2

    Science.gov (United States)

    2014-03-01

    Defence Science and Technology Organisation Technical Report DSTO-TR-1622, 2004. [3] Barlow, J. B., Rae , W. H. and Pope, A., Low-Speed Wind Tunnel...kW (900 hp) electric motor driving a 3.96 m diameter eight bladed fan, with a maximum rotational speed 750 RPM, manually controlled. Cooling 40 °C

  18. Film thickness of mechanically worked lubricating grease at very low speeds

    NARCIS (Netherlands)

    Cen, H.; Lugt, Pieter Martin; Morales-Espejel, G.E.

    2014-01-01

    Several different types of commercially available greases, aged in a roll stability tester, have been tested in a ball-on-disc machine where the film thickness was measured using the interferometry method. The grease film thickness at very low speed is thicker than the base oil film thickness due to

  19. Evaluation of spray drift using low speed wind tunnel measurements and dispersion modeling

    Science.gov (United States)

    The objective of this work was to evaluate the EPA’s proposed Test Plan for the validation testing of pesticide spray drift reduction technologies (DRTs) for row and field crops, focusing on the evaluation of ground application systems using the low-speed wind tunnel protocols and processing the dat...

  20. Low speed hybrid generalized predictive control of a gasoline-propelled car.

    Science.gov (United States)

    Romero, M; de Madrid, A P; Mañoso, C; Milanés, V

    2015-07-01

    Low-speed driving in traffic jams causes significant pollution and wasted time for commuters. Additionally, from the passengers׳ standpoint, this is an uncomfortable, stressful and tedious scene that is suitable to be automated. The highly nonlinear dynamics of car engines at low-speed turn its automation in a complex problem that still remains as unsolved. Considering the hybrid nature of the vehicle longitudinal control at low-speed, constantly switching between throttle and brake pedal actions, hybrid control is a good candidate to solve this problem. This work presents the analytical formulation of a hybrid predictive controller for automated low-speed driving. It takes advantage of valuable characteristics supplied by predictive control strategies both for compensating un-modeled dynamics and for keeping passengers security and comfort analytically by means of the treatment of constraints. The proposed controller was implemented in a gas-propelled vehicle to experimentally validate the adopted solution. To this end, different scenarios were analyzed varying road layouts and vehicle speeds within a private test track. The production vehicle is a commercial Citroën C3 Pluriel which has been modified to automatically act over its throttle and brake pedals.

  1. Adaptive compressive sensing camera

    Science.gov (United States)

    Hsu, Charles; Hsu, Ming K.; Cha, Jae; Iwamura, Tomo; Landa, Joseph; Nguyen, Charles; Szu, Harold

    2013-05-01

    We have embedded Adaptive Compressive Sensing (ACS) algorithm on Charge-Coupled-Device (CCD) camera based on the simplest concept that each pixel is a charge bucket, and the charges comes from Einstein photoelectric conversion effect. Applying the manufactory design principle, we only allow altering each working component at a minimum one step. We then simulated what would be such a camera can do for real world persistent surveillance taking into account of diurnal, all weather, and seasonal variations. The data storage has saved immensely, and the order of magnitude of saving is inversely proportional to target angular speed. We did design two new components of CCD camera. Due to the matured CMOS (Complementary metal-oxide-semiconductor) technology, the on-chip Sample and Hold (SAH) circuitry can be designed for a dual Photon Detector (PD) analog circuitry for changedetection that predicts skipping or going forward at a sufficient sampling frame rate. For an admitted frame, there is a purely random sparse matrix [Φ] which is implemented at each bucket pixel level the charge transport bias voltage toward its neighborhood buckets or not, and if not, it goes to the ground drainage. Since the snapshot image is not a video, we could not apply the usual MPEG video compression and Hoffman entropy codec as well as powerful WaveNet Wrapper on sensor level. We shall compare (i) Pre-Processing FFT and a threshold of significant Fourier mode components and inverse FFT to check PSNR; (ii) Post-Processing image recovery will be selectively done by CDT&D adaptive version of linear programming at L1 minimization and L2 similarity. For (ii) we need to determine in new frames selection by SAH circuitry (i) the degree of information (d.o.i) K(t) dictates the purely random linear sparse combination of measurement data a la [Φ]M,N M(t) = K(t) Log N(t).

  2. ccdAB system and the encoding toxin protein-CcdB%ccdAB系统及其编码的毒素蛋白CcdB

    Institute of Scientific and Technical Information of China (English)

    贾卉; 井申荣

    2009-01-01

    ccdAB系统(control of cell division or death system)是目前已知的一种毒素-抗毒素系统(toxin-antitoxin system,TA系统),存在于致病性大肠杆菌F质粒及染色体骨架上,由ccdA和ccdB两个基因组成.质粒上的ccdAB系统编码一种毒素蛋白CcdB,在缺乏抗毒素的情况下,CcdB使细胞内促旋酶中毒,从而干扰DNA的合成,杀伤宿主细胞.本文对ccdAB系统的结构和功能,以及所编码CcdB的作用机制进行了综述.

  3. CCD Photometry of bright stars using objective wire mesh

    Energy Technology Data Exchange (ETDEWEB)

    Kamiński, Krzysztof; Zgórz, Marika [Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286 Poznań (Poland); Schwarzenberg-Czerny, Aleksander, E-mail: chrisk@amu.edu.pl [Copernicus Astronomical Centre, ul. Bartycka 18, PL 00-716 Warsaw (Poland)

    2014-06-01

    Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on β Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag per two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.

  4. Non-linear backstepping control of five-phase IM drive at low speed conditions-experimental implementation.

    Science.gov (United States)

    Echeikh, Hamdi; Trabelsi, Ramzi; Iqbal, Atif; Bianchi, Nicola; Mimouni, Mohamed Fouizi

    2016-11-01

    In this paper non-linear backstepping control (BSC) is employed for high performance five-phase induction motor drive for low speed operation. The traditional control approaches such as direct torque control and indirect rotor field oriented control introduces stability problem at low speed. The proposed BSC is shown to offer stable operation in the sense of Lyapunov and high dynamics at low speed. Experimental results are provided to present the proprieties of the proposed approach at low speed in terms of stability, torque ripple, desired control performance, achievable dynamics and complexity of implementation etc. Copyright © 2016. Published by Elsevier Ltd.

  5. CCD Readout Electronics for the Subaru Prime Focus Spectrograph

    CERN Document Server

    Hope, Stephen C; Loomis, Craig P; Fitzgerald, Roger E; Peacock, Grant O

    2014-01-01

    We present details of the design for the CCD readout electronics for the Subaru Telescope Prime Focus Spectrograph (PFS). The spectrograph is comprised of four identical spectrograph modules, each collecting roughly 600 spectra. The spectrograph modules provide simultaneous wavelength coverage over the entire band from 380 nm to 1260 nm through the use of three separate optical channels: blue, red, and near infrared (NIR). A camera in each channel images the multi-object spectra onto a 4k x 4k, 15 um pixel, detector format. The two visible cameras use a pair of Hamamatsu 2k x 4k CCDs with readout provided by custom electronics, while the NIR camera uses a single Teledyne HgCdTe 4k x 4k detector and ASIC Sidecar to read the device. The CCD readout system is a custom design comprised of three electrical subsystems: the Back End Electronics (BEE), the Front End Electronics (FEE), and a Pre-amplifier. The BEE is an off-the-shelf PC104 computer, with an auxiliary Xilinx FPGA module. The computer serves as the main...

  6. Longitudinal Acceleration Tracking Control of Low Speed Heavy-Duty Vehicles

    Institute of Scientific and Technical Information of China (English)

    WANG Yuejian; BIN Yang; LI Keqiang

    2008-01-01

    This paper presents a model matching control (MMC) method based on the sliding mode control(SMC) method for longitudinal acceleration tracking control in a vehicular stop-and-go cruise control system.The nonlinearity of the vehicle acceleration response at low speeds was analyzed to develop a transfer function model of the vehicle longitudinal dynamics using the least-mean-square system identification technique.This transfer function was then used to design the MMC controller,including an SMC feedback compensator.The system combines the advantages of the two control methods with robust control and rapid response.Simulations show that the controller enhances the rapid trackability to the vehicle acceleration and improves the system's robustness at low speeds compared with conventional PID MMC controllers.

  7. SOME CHARACTERISTICS OF LOW-SPEED STREAKS UNDER SHEARED AIR-WATER INTERFACES

    Institute of Scientific and Technical Information of China (English)

    王双峰; 贾复

    2001-01-01

    The characteristics of low-speed fluid streaks occurring under sheared air-water interfaces were examined by means of hydrogen bubble visualization tech nique. A critical shear condition under which the streaky structure first appears was determined to be uT ≈ 0.19 cm/s. The mean spanwise streak spacing increases with distance from the water surface owing to merging and bursting processes, and a lin ear relationship describing variation of non-dimensional spacing λ+- versus y+ was found essentially independent of shear stress on the interface. Values ofλ+, however,are remarkably smaller than their counterparts in the near-wall region of turbulent boundary layers. Though low-speed streaks occur randomly in time and space, the streak spacing exhibits a lognormal probability distribution behavior. A tentative explanation concerning the formation of streaky structure is suggested, and the fact that λ+ takes rather smaller values than that in wall turbulence is briefly discussed.

  8. A learning-based autonomous driver: emulate human driver's intelligence in low-speed car following

    Science.gov (United States)

    Wei, Junqing; Dolan, John M.; Litkouhi, Bakhtiar

    2010-04-01

    In this paper, an offline learning mechanism based on the genetic algorithm is proposed for autonomous vehicles to emulate human driver behaviors. The autonomous driving ability is implemented based on a Prediction- and Cost function-Based algorithm (PCB). PCB is designed to emulate a human driver's decision process, which is modeled as traffic scenario prediction and evaluation. This paper focuses on using a learning algorithm to optimize PCB with very limited training data, so that PCB can have the ability to predict and evaluate traffic scenarios similarly to human drivers. 80 seconds of human driving data was collected in low-speed (car-following scenarios. In the low-speed car-following tests, PCB was able to perform more human-like carfollowing after learning. A more general 120 kilometer-long simulation showed that PCB performs robustly even in scenarios that are not part of the training set.

  9. The Effects of Fuels and Lubricants on Low- Speed Pre- Ignition in Gasoline SI Engines

    Institute of Scientific and Technical Information of China (English)

    Eric LIU

    2012-01-01

    With the onset of downsized and highly- boosted engines, engine designers are encountering a new combustion phenomenon, called low - speed pre - ignition (LSPI) or superknock, which occurs when the engine operates under a low - speed, high - load conditions. LSPI events cause large spikes in cylinder pressure that can easily exceed the design limits of the engine. Therefore, it is important for the automotive industry to understand how LSPI events occur and develop a so- lution that can either eliminate it or detect and mitigate its effects. This paper summarizes the existing work that has been conducted on the subject of LSPI. Much of presented hypothesizes that physical and chemical interactions and accumulation of fuels and lubricants in crevice volume affect the frequency of LPSl events. Therefore, it may be possible to formulate fuels and mitigate or eliminate the occurrence of LPSI. the research work the piston top land lubricants that can

  10. Computer simulations and experimental study on crash box of automobile in low speed collision

    Science.gov (United States)

    Liu, Yanjie; Ding, Lin; Yan, Shengyuan; Yang, Yongsheng

    2008-11-01

    Based on the problems of energy-absorbing components in the automobile low speed collision process, according to crash box frontal crash test in low speed as the example, the simulation analysis of crash box impact process was carried out by Hyper Mesh and LS-DYNA. Each parameter on the influence modeling was analyzed by mathematics analytical solution and test comparison, which guaranteed that the model was accurate. Combination of experiment and simulation result had determined the weakness part of crash box structure crashworthiness aspect, and improvement method of crash box crashworthiness was discussed. Through numerical simulation of the impact process of automobile crash box, the obtained analysis result was used to optimize the design of crash box. It was helpful to improve the vehicles structure and decrease the collision accident loss at most. And it was also provided a useful method for the further research on the automobile collision.

  11. Unstable phenomena of low speed compressible natural convection with open boundaries by multi-GPU implementation

    Science.gov (United States)

    Wang, Wei-Hsiang; Fu, Wu-Shung; Tsubokura, Makoto

    2016-11-01

    Unstable phenomena of low speed compressible natural convection are investigated numerically. Geometry contains parallel square plates or single heated plate with open boundaries is taken into consideration. Numerical methods of the Roe scheme, preconditioning and dual time stepping matching the DP-LUR method are used for low speed compressible flow. The absorbing boundary condition and modified LODI method is adopted to solve open boundary problems. High performance parallel computation is achieved by multi-GPU implementation with CUDA platform. The effects of natural convection by isothermal plates facing upwards in air is then carried out by the methods mentioned above Unstable behaviors appeared upon certain Rayleigh number with characteristic length respect to the width of plates or height between plates.

  12. Sensorless Characteristics of Hybrid PM Machines at Zero and Low Speed

    DEFF Research Database (Denmark)

    Matzen, Torben N.; Rasmussen, Peter Omand

    2009-01-01

    for analysing the suitability for sensorless control at zero and low speed. The method can be used to evaluate a particular machine design so the self-sensing characteristics for sensorless control of machine can be found. The characteristics can be obtained from finite element simulation data or experimental......Sensorless methods for zero and low speed operation in drives with hybrid PM machines make use of the machine saliency to determine the rotor position in an indirect fashion. When integrating the position measurement in the electrical power supply to the machine, i.e. make the machine self......-sensing, the sensorless obtained position can be affected by the actual operation conditions of the machine e.g. the stator currents. This may deteriorate the machine self-sensing suitability using injection methods. In this paper an analysis method based on accurate knowledge of the machine flux linkages is proposed...

  13. Low speed axial compressor stall margin improvement by unsteady plasma actuation

    Science.gov (United States)

    Li, Gang; Xu, Yanji; Yang, Lingyuan; Du, Wei; Zhu, Junqiang; Nie, Chaoqun

    2014-04-01

    This research investigates the use of single dielectric barrier discharge (SDBD) actuators for energizing the tip leakage flow to suppress rotating stall inception and extend the stable operating range of a low speed axial compressor with a single rotor. The jet induced by the plasma actuator adds momentum to the flow in the tip region and has a significant impact on the tip-gap flow. Experiments are carried out on a low speed axial compressor with a single rotor. The static pressure is measured at both the rotor inlet and outlet. The flow coefficient and pressure rise coefficient are calculated. Then the characteristic line is acquired to show the overall performance of the compressor. With unsteady plasma actuation of 18kV and 60W the compressor stability range improvement is realized at rotor speed of 1500 r/min — 2400 r/min.

  14. Application of Dual-blade Stator to Low-speed Ratio Performance Improvement of Torque Converters

    Institute of Scientific and Technical Information of China (English)

    WU Guangqiang; WANG Lijun

    2016-01-01

    With application of the lock-up clutch in the torque converter (TC), fuel economy is not much determined by its high-speed ratio transmission efficiency. As a benefit, more researches are focused on its low-speed ratio performance so as to improve vehicle gradeability and launching acceleration performance. According to the results of computational fluid dynamics (CFD) analysis, hydrodynamic loss inside the stator cascade accounts for 42% of the total energy loss at stalling speed ratio. It is found that upstream flow with large impingement angle results in boundary layer separation at the leading edge, which aggregates hydrodynamic loss and decreases circular flow rate dramatically at low-speed ratio. In this paper, a dual-blade stator is proposed to suppress the boundary layer separation, which is parameterized by using the non-uniform rational B spline (NURBS) method. The mean camber line and blade profile curve are expressed by a three control points quadratic open NURBS and a cubic closed one respectively. The key design parameters included the slot width and suction side shape of the primary blade are analyzed. The most effective slot width is found to be between 4% and 8% chord length, and the boundary layer separation can be suppressed completely by decreasing distribution of momentum moment at the primary blade and adding it to the leading edge of the secondary blade. As a result, circular flow rate and impeller torque capacity is increased by 17.9% and 9.6% respectively at stalling speed ratio, meanwhile, low-speed ratio efficiency is also improved. Maximum efficiency at high-speed ratio decreases by 0.5%, which can be ignored as the work of lock-up clutch. This research focuses on using the dual-blade stator to optimize low-speed ratio performance of the TC, which is benefit to vehicle power performance.

  15. Application of dual-blade stator to low-speed ratio performance improvement of torque converters

    Science.gov (United States)

    Wu, Guangqiang; Wang, Lijun

    2016-03-01

    With application of the lock-up clutch in the torque converter (TC), fuel economy is not much determined by its high-speed ratio transmission efficiency. As a benefit, more researches are focused on its low-speed ratio performance so as to improve vehicle gradeability and launching acceleration performance. According to the results of computational fluid dynamics (CFD) analysis, hydrodynamic loss inside the stator cascade accounts for 42% of the total energy loss at stalling speed ratio. It is found that upstream flow with large impingement angle results in boundary layer separation at the leading edge, which aggregates hydrodynamic loss and decreases circular flow rate dramatically at low-speed ratio. In this paper, a dual-blade stator is proposed to suppress the boundary layer separation, which is parameterized by using the non-uniform rational B spline (NURBS) method. The mean camber line and blade profile curve are expressed by a three control points quadratic open NURBS and a cubic closed one respectively. The key design parameters included the slot width and suction side shape of the primary blade are analyzed. The most effective slot width is found to be between 4% and 8% chord length, and the boundary layer separation can be suppressed completely by decreasing distribution of momentum moment at the primary blade and adding it to the leading edge of the secondary blade. As a result, circular flow rate and impeller torque capacity is increased by 17.9% and 9.6% respectively at stalling speed ratio, meanwhile, low-speed ratio efficiency is also improved. Maximum efficiency at high-speed ratio decreases by 0.5%, which can be ignored as the work of lock-up clutch. This research focuses on using the dual-blade stator to optimize low-speed ratio performance of the TC, which is benefit to vehicle power performance.

  16. Investigation of Load and Pressure Distribution onWing with Wake Rollup for Low Speed Aircraft

    OpenAIRE

    Laith W. Ismail

    2008-01-01

    The presented work shows a preliminary analytic method for estimation of load and pressure distributions on low speed wings with flow separation and wake rollup phenomenas. A higher order vortex panel method is coupled with the numerical lifting line theory by means of iterative procedure including models of separation and wake rollup. The computer programs are written in FORTRAN which are stable and efficient. The capability of the present method is investigated through a number of test case...

  17. A Study of Slipper and Rail Wear Interaction at Low Speed

    Science.gov (United States)

    2014-06-19

    taking care of the boys, a house and a dog and for not getting discouraged. I pray that they will learn as I have how important it is to ensure Yahovah...wear, delamination wear, seizure wear, melt wear, severe oxidational wear and adhesive wear. Adhesive wear comprised of three zones: low speed...model is experiencing seizure or melt wear, then something is wrong with the model. Lim and Ashby also published on their wear map the normalized wear

  18. Temperature change in pig rib bone during implant site preparation by low-speed drilling

    Directory of Open Access Journals (Sweden)

    Sun-Jong Kim

    2010-10-01

    Full Text Available OBJECTIVES: The purpose of this study was to evaluate the temperature change during low-speed drilling using infrared thermography. MATERIAL AND METHODS: Pig ribs were used to provide cortical bone of a similar quality to human mandible. Heat production by three implant drill systems (two conventional drilling systems and one low-speed drilling system was evaluated by measuring the bone temperature using infrared thermography. Each system had two different bur sizes. The drill systems used were twist drill (2.0 mm/2.5 mm, which establishes the direction of the implant, and finally a 3.0 mm-pilot drill. Thermal images were recorded using the IRI1001 system (Infrared Integrated Systems Ltd.. Baseline temperature was 31±1ºC. Measurements were repeated 10 times, and a static load of 10 kg was applied while drilling. Data were analyzed using descriptive statistics. Statistical analysis was conducted with two-way ANOVA. RESULTS AND CONCLUSIONS: Mean values (n=10 drill sequences for maximum recorded temperature (Max TºC, change in temperature (ΔTºC from baseline were as follows. The changes in temperature (ΔTºC were 1.57ºC and 2.46ºC for the lowest and the highest values, respectively. Drilling at 50 rpm without irrigation did not produce overheating. There was no significant difference in heat production between the 3 implant drill systems (p>0.05. No implant drill system produced heat exceeding 47ºC, which is the critical temperature for bone necrosis during low-speed drilling. Low-speed drilling without irrigation could be used during implant site preparation.

  19. Reconstruction of Low Speed Rear-End collisions - Technical Means of Assessing Cervical Spine Injuries

    Directory of Open Access Journals (Sweden)

    Martin Hitzemann

    2003-01-01

    Full Text Available In recent years, an increasing number of cervical spine injuries sustained by vehicle occupants in collisions at comparatively low speeds have been reported to insurance companies and in civil litigation. The reported injuries occur in both rear-end and side impact collisions. The paper describes how a detailed assessment of such cases requires interdisciplinary teamwork involving technical, biomechanical and medical experts.

  20. Hysteresis zone or locus - Aerodynamic of bulbous based bodies at low speeds

    Science.gov (United States)

    Covert, E. E.

    1979-01-01

    Experimental data are presented which seem to suggest that a well-defined hysteresis locus on bulbous based bodies at low speeds does not exist. Instead, if the experiment is repeated several times, the entire hysteresis region seems to fill with data rather than trace out a specific hysteresis locus. Data obtained on an oscillating model even at low reduced frequencies may be well defined but when applied to arbitrary motion lead to less accurate results than desired.

  1. Research on the low speed stability control technology of fly-cutting machine for KDP crystals

    Science.gov (United States)

    Chen, Dongsheng; Ji, Fang; Chen, Hua

    2014-08-01

    In the paper, The problem about stability in low speed of the air bearing stage driven by a linear motor was investigated to satisfy the ultra-precision fly-cutting of KDP crystals. First of all, the modal of the servo system with the permanent magnet synchronous linear motor was analyzed. In the system of the low speed linear motor driver, the main interferences came from cutting force f Load , the friction of chain and cable f n , the ripple thrust f ripp , and motor friction f fric . Secondly, the factors about low speed stability were analyzed: the key to improve the system's stability is to control the interference forces; Another important issue is to develop an advanced control strategy. Thirdly, some optimization experiments about low speed stability were developed as follows: the influence of feedback element, the influence of Power converter, speed optimization of damping feed-forward control, speed optimization of Spindle vibration, speed optimization based on disturbance observer. Finally the experimental results: the lowest speed of the stage can reach 0.2 mm/min; the error of the speed is less than 0.06mm/min when running between 1mm/min and 10 mm/min. The cutting experiment of KDP with the size of 330mm × 330mm × 10mm, was proceeded on the Fly-cutting machine by the feeding velocity of 1mm/min. The results about the surface roughness show that the value of Rq is 3.3nm and the value of Ra is 2.6nm.

  2. Gravitationally defined velocities for a low speed hot-wire calibration

    Science.gov (United States)

    Haw, R. C.; Ali, S. K.; Foss, J. F.

    1987-01-01

    A technique to provide the reference velocity for a low speed hot-wire calibration is described. A pivoted arm falls under the action of gravity and the resulting velocity field can be used to define the transfer function coefficients in a modified Collis and Williams (1959) relationship. In nominal agreement with a published result, a deviation from this relationship for a film Reynolds number such that Re exp n of less than about 0.24 is observed.

  3. Very-low speed control of PMSM based on EKF estimation with closed loop optimized parameters.

    Science.gov (United States)

    Xu, Dong; Zhang, Shaoguang; Liu, Jingmeng

    2013-11-01

    When calculating the speed from the position of permanent magnet synchronous motor (PMSM), the accuracy and real-time are limited by the precision of the sensor. This problem causes crawling and jitter at very-low speed. Using the angle from the position sensor, an extended Kalman filter (EKF) designed in dq-coordinate is presented to solve this problem. The usage of position sensor simplifies the model and improves the accuracy of speed estimation. Specially, a closed loop optimal (CLO) method is devised to overcome the difficulty to adjust the parameters of the EKF. The EKF is the feedback link of speed control, CLO method is derived from the perspective of the speed step response to optimize the measurement covariance matrix and the system covariance matrix of EKF. Simulation and experimental results, comparing the low-speed performance of the EKF and sensor feedback methods, prove the effectiveness of the method to adjust the parameters of EKF and the advantages in eliminating the low speed jitter.

  4. Acoustic emission-based condition monitoring methods: Review and application for low speed slew bearing

    Science.gov (United States)

    Caesarendra, Wahyu; Kosasih, Buyung; Tieu, Anh Kiet; Zhu, Hongtao; Moodie, Craig A. S.; Zhu, Qiang

    2016-05-01

    This paper presents an acoustic emission-based method for the condition monitoring of low speed reversible slew bearings. Several acoustic emission (AE) hit parameters as the monitoring parameters for the detection of impending failure of slew bearings are reviewed first. The review focuses on: (1) the application of AE in typical rolling element bearings running at different speed classifications, i.e. high speed (>600 rpm), low speed (10-600 rpm) and very low speed (<10 rpm); (2) the commonly used AE hit parameters in rolling element bearings and (3) AE signal processing, feature extraction and pattern recognition methods. In the experiment, impending failure of the slew bearing was detected by the AE hit parameters after the new bearing had run continuously for approximately 15 months. The slew bearing was then dismantled and the evidence of the early defect was analysed. Based on the result, we propose a feature extraction method of the AE waveform signal using the largest Lyapunov exponent (LLE) algorithm and demonstrate that the LLE feature can detect the sign of failure earlier than the AE hit parameters with improved prediction of the progressive trend of the defect.

  5. Subpixel translation of MEMS measured by discrete fourier transform analysis of CCD images

    NARCIS (Netherlands)

    Yamahata, C.; Sarajlic, Edin; Stranczl, M.; Krijnen, Gijsbertus J.M.; Gijs, M.A.M.

    2011-01-01

    We present a straightforward method for measuring in-plane linear displacements of microelectromechanical systems (MEMS) with subnanometer resolution. The technique is based on Fourier transform analysis of a video recorded with a Charge-Coupled Device (CCD) camera attached to an optical microscope

  6. Subpixel translation of MEMS measured by discrete fourier transform analysis of CCD images

    NARCIS (Netherlands)

    Yamahata, C.; Sarajlic, E.; Stranczl, M.; Krijnen, G.J.M.; Gijs, M.A.M.

    2011-01-01

    We present a straightforward method for measuring in-plane linear displacements of microelectromechanical systems (MEMS) with subnanometer resolution. The technique is based on Fourier transform analysis of a video recorded with a Charge-Coupled Device (CCD) camera attached to an optical microscope

  7. Medición de coeficientes de extinción en CASLEO y características del CCD ROPER-2048B del telescopio JS

    Science.gov (United States)

    Fernández-Lajús, E.; Gamen, R.; Sánchez, M.; Scalia, M. C.; Baume, G. L.

    2016-08-01

    From observations made with the ``Jorge Sahade'' telescope of the Complejo Astronomico El Leoncito, the UBVRI-band extinction coeficients were measured, and some parameters and characteristics of the direct-image CCD camera ROPER 2048B were determined.

  8. Disturbance observer that uses radial basis function networks for the low speed control of a servo motor

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Bae, C.H.; Blaabjerg, Frede

    2005-01-01

    A scheme to estimate the moment of inertia in a servo motor drive system at very low speed is proposed. The typical speed estimation scheme used in most servo systems operated at low speed is highly sensitive to variations in the moment of inertia. An observer that uses a radial basis function ne...

  9. The ratio between CcdA and CcdB modulates the transcriptional repression of the ccd poison-antidote system.

    Science.gov (United States)

    Afif, H; Allali, N; Couturier, M; Van Melderen, L

    2001-07-01

    The ccd operon of the F plasmid encodes CcdB, a toxin targeting the essential gyrase of Escherichia coli, and CcdA, the unstable antidote that interacts with CcdB to neutralize its toxicity. Although work from our group and others has established that CcdA and CcdB are required for transcriptional repression of the operon, the underlying mechanism remains unclear. The results presented here indicate that, although CcdA is the DNA-binding element of the CcdA-CcdB complex, the stoichiometry of the two proteins determines whether or not the complex binds to the ccd operator-promoter region. Using electrophoretic mobility shift assays, we show that a (CcdA)2-(CcdB)2 complex binds DNA. The addition of extra CcdB to that protein-DNA complex completely abolishes DNA retardation. Based on these results, we propose a model in which the ratio between CcdA and CcdB regulates the repression state of the ccd operon. When the level of CcdA is superior or equal to that of CcdB, repression results. In contrast, derepression occurs when CcdB is in excess of CcdA. By ensuring an antidote-toxin ratio greater than one, this mechanism could prevent the harmful effect of CcdB in plasmid-containing bacteria.

  10. CCD based beam loss monitor for ion accelerators

    Science.gov (United States)

    Belousov, A.; Mustafin, E.; Ensinger, W.

    2014-04-01

    Beam loss monitoring is an important aspect of proper accelerator functioning. There is a variety of existing solutions, but each has its own disadvantages, e.g. unsuitable dynamic range or time resolution, high cost, or short lifetime. Therefore, new options are looked for. This paper shows a method of application of a charge-coupled device (CCD) video camera as a beam loss monitor (BLM) for ion beam accelerators. The system was tested with a 500 MeV/u N+7 ion beam interacting with an aluminum target. The algorithms of camera signal processing with LabView based code and beam loss measurement are explained. Limits of applicability of this monitor system are discussed.

  11. Illumination box and camera system

    Science.gov (United States)

    Haas, Jeffrey S.; Kelly, Fredrick R.; Bushman, John F.; Wiefel, Michael H.; Jensen, Wayne A.; Klunder, Gregory L.

    2002-01-01

    A hand portable, field-deployable thin-layer chromatography (TLC) unit and a hand portable, battery-operated unit for development, illumination, and data acquisition of the TLC plates contain many miniaturized features that permit a large number of samples to be processed efficiently. The TLC unit includes a solvent tank, a holder for TLC plates, and a variety of tool chambers for storing TLC plates, solvent, and pipettes. After processing in the TLC unit, a TLC plate is positioned in a collapsible illumination box, where the box and a CCD camera are optically aligned for optimal pixel resolution of the CCD images of the TLC plate. The TLC system includes an improved development chamber for chemical development of TLC plates that prevents solvent overflow.

  12. Optical and dark characterization of the PLATO CCD at ESA

    Science.gov (United States)

    Verhoeve, Peter; Prod'homme, Thibaut; Oosterbroek, Tim; Duvet, Ludovic; Beaufort, Thierry; Blommaert, Sander; Butler, Bart; Heijnen, Jerko; Lemmel, Frederic; van der Luijt, Cornelis; Smit, Hans; Visser, Ivo

    2016-07-01

    PLATO - PLAnetary Transits and Oscillations of stars - is the third medium-class mission (M3) to be selected in the European Space Agency (ESA) Science and Robotic Exploration Cosmic Vision programme. It is due for launch in 2025 with the main objective to find and study terrestrial planets in the habitable zone around solar-like stars. The payload consists of >20 cameras; with each camera comprising 4 Charge-Coupled Devices (CCDs), a large number of flight model devices procured by ESA shall ultimately be integrated on the spacecraft. The CCD270 - specially designed and manufactured by e2v for the PLATO mission - is a large format (8 cm x 8 cm) back-illuminated device operating at 4 MHz pixel rate and coming in two variants: full frame and frame transfer. In order to de-risk the PLATO CCD procurement and aid the mission definition process, ESA's Payload Technology Validation section is currently validating the PLATO CCD270. This validation consists in demonstrating that the device achieves its specified electrooptical performance in the relevant environment: operated at 4 MHz, at cold and before and after proton irradiation. As part of this validation, CCD270 devices have been characterized in the dark as well as optically with respect to performance parameters directly relevant for the photometric application of the CCDs. Dark tests comprise the measurement of gain sensitivity to bias voltages, charge injection tests, and measurement of hot and variable pixels after irradiation. In addition, the results of measurements of Quantum Efficiency for a range of angles of incidence, intra- pixel response (non-)uniformity, and response to spot illumination, before and after proton irradiation. In particular, the effect of radiation induced degradation of the charge transfer efficiency on the measured charge in a star-like spot has been studied as a function of signal level and of position on the pixel grid, Also, the effect of various levels of background light on the

  13. Evaluation of a scientific CMOS camera for astronomical observations

    Institute of Scientific and Technical Information of China (English)

    Peng Qiu; Yong-Na Mao; Xiao-Meng Lu; E Xiang; Xiao-Jun Jiang

    2013-01-01

    We evaluate the performance of the first generation scientific CMOS (sCMOS) camera used for astronomical observations.The sCMOS camera was attached to a 25 cm telescope at Xinglong Observatory,in order to estimate its photometric capabilities.We further compared the capabilities of the sCMOS camera with that of full-frame and electron multiplying CCD cameras in laboratory tests and observations.The results indicate the sCMOS camera is capable of performing photometry of bright sources,especially when high spatial resolution or temporal resolution is desired.

  14. Coaxial fundus camera for opthalmology

    Science.gov (United States)

    de Matos, Luciana; Castro, Guilherme; Castro Neto, Jarbas C.

    2015-09-01

    A Fundus Camera for ophthalmology is a high definition device which needs to meet low light illumination of the human retina, high resolution in the retina and reflection free image1. Those constraints make its optical design very sophisticated, but the most difficult to comply with is the reflection free illumination and the final alignment due to the high number of non coaxial optical components in the system. Reflection of the illumination, both in the objective and at the cornea, mask image quality, and a poor alignment make the sophisticated optical design useless. In this work we developed a totally axial optical system for a non-midriatic Fundus Camera. The illumination is performed by a LED ring, coaxial with the optical system and composed of IR of visible LEDs. The illumination ring is projected by the objective lens in the cornea. The Objective, LED illuminator, CCD lens are coaxial making the final alignment easily to perform. The CCD + capture lens module is a CCTV camera with autofocus and Zoom built in, added to a 175 mm focal length doublet corrected for infinity, making the system easily operated and very compact.

  15. Measurement of spatial object's exterior attitude based on linear CCD

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It is difficult to realize real-time measurement of exterior attitude by the traditional systems based on the area image sensor which have conflict between speed and accuracy.The subsystem for three-dimensional (3D) coordinate rcconstruction of point target (S3DCRPT) which is composed of three one-dimensional (1D) cameras based on linear charge-coupled device (CCD) can determine the distant light spots' spatial position. The attitude angle of the measured object is determined by the spatial solution while the coordinate reconstruction is separately carried on by the S3DCRPT with some point cooperation targets (PCTs) on the measured object. A new optical system is designed to solve the interference problem with one-to-one relationship between the PCTs and the S3DCRPT optical subsystems,which improves the measurement accuracy and saves space. The mathematical model of the attitude measurement is established,and partial and global calibrations are realized for the multi-camera attitude measurement system.The test results show the feasibility of the exterior attitude measurement based on linear CCD.

  16. LUBRICATION FILM FORMATION MECHANISM OF SLIPPER PAIRS IN LOW SPEED HIGH TORQUE HYDRAULIC MOTORS

    Institute of Scientific and Technical Information of China (English)

    LI Yong; SHI Guanglin; CHEN Zhaoneng

    2007-01-01

    Pressure-flow analytical formulas of lubrication film of slipper pairs on camshaft connecting rod type low speed high torque (LSHT) hydraulic motors are put forward. The bottom surface of slipper pairs is rectangle, and the effect of squeeze flow and pressure differential flow is considered. The dynamic process of lubrication film formation through squeezing is numerically studied by computer simulation. Effects of supply pressure, initial lubrication film thickness, velocity damping coefficient, loading impact and gravity, etc are studied. Advantages of novel slipper pairs with large oil cavity area are pointed out.

  17. Minimum-Voltage Vector Injection Method for Sensorless Control of PMSM for Low-Speed Operations

    DEFF Research Database (Denmark)

    Xie, Ge; Lu, Kaiyuan; Kumar, Dwivedi Sanjeet

    2016-01-01

    In this paper, a simple signal injection method is proposed for sensorless control of PMSM at low speed, which ideally requires one voltage vector only for position estimation. The proposed method is easy to implement resulting in low computation burden. No filters are needed for extracting...... may also be further developed to inject two opposite voltage vectors to reduce the effects of inverter voltage error on the position estimation accuracy. The effectiveness of the proposed method is demonstrated by comparing with other sensorless control method. Theoretical analysis and experimental...

  18. PIV Measurements in the 14 x 22 Low Speed Tunnel: Recommendations for Future Testing

    Science.gov (United States)

    Watson, Ralph D.; Jenkins, Luther N.; Yao, Chung-Sheng; McGinley, Catherine B.; Paschal, Keith B.; Neuhart, Dan H.

    2003-01-01

    During the period from February 4 to March 21, 2003 stereo digital particle imaging velocimetry measurements were made on a generic high lift model, the Trap Wing, as part of the High Lift Flow Physics Experiment. These measurements were the first PIV measurements made in the NASA, Langley Research Center 14 x 22 Foot Low Speed Tunnel, and several problems were encountered and solved in the acquisition of the data. It is the purpose of this paper to document the solutions to these problems and to make recommendations for further improvements to the tunnel/setup in order to facilitate future measurements of this type.

  19. Status of The General Atomics Low Speed Urban Maglev Technology Development Program

    Energy Technology Data Exchange (ETDEWEB)

    Gurol, S; Baldi, R; Bever, D; Post, R

    2004-06-16

    This paper presents the status of General Atomics Urban Maglev Program. The development provides an innovative approach for low speed transportation suitable for very challenging urban environments. Permanent magnets arranged in a 'Halbach' array configuration produce a relatively stiff magnetic suspension operating with an air gap of 25 mm. The project has progressed from design and prototype hardware testing, to the construction of a 120-meter full-scale test track, located in San Diego, California. Dynamic testing of the levitation, propulsion and guidance systems is being performed.

  20. The Acoustic Environment of the NASA Glenn 9- by 15-foot Low-Speed Wind Tunnel

    Science.gov (United States)

    Stephens, David B.

    2015-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel is an acoustic testing facility with a long history of aircraft propulsion noise research. Due to interest in renovating the facility to support future testing of advanced quiet engine designs, a study was conducted to document the background noise level in the facility and investigate the sources of contaminating noise. The anechoic quality of the facility was also investigated using an interrupted noise method. The present report discusses these aspects of the noise environment in this facility.

  1. CCD research. [design, fabrication, and applications

    Science.gov (United States)

    Gassaway, J. D.

    1976-01-01

    The fundamental problems encountered in designing, fabricating, and applying CCD's are reviewed. Investigations are described and results and conclusions are given for the following: (1) the development of design analyses employing computer aided techniques and their application to the design of a grapped structure; (2) the role of CCD's in applications to electronic functions, in particular, signal processing; (3) extending the CCD to silicon films on sapphire (SOS); and (4) all aluminum transfer structure with low noise input-output circuits. Related work on CCD imaging devices is summarized.

  2. Tower Camera

    Data.gov (United States)

    Oak Ridge National Laboratory — The tower camera in Barrow provides hourly images of ground surrounding the tower. These images may be used to determine fractional snow cover as winter arrives, for...

  3. Cardiac cameras.

    Science.gov (United States)

    Travin, Mark I

    2011-05-01

    Cardiac imaging with radiotracers plays an important role in patient evaluation, and the development of suitable imaging instruments has been crucial. While initially performed with the rectilinear scanner that slowly transmitted, in a row-by-row fashion, cardiac count distributions onto various printing media, the Anger scintillation camera allowed electronic determination of tracer energies and of the distribution of radioactive counts in 2D space. Increased sophistication of cardiac cameras and development of powerful computers to analyze, display, and quantify data has been essential to making radionuclide cardiac imaging a key component of the cardiac work-up. Newer processing algorithms and solid state cameras, fundamentally different from the Anger camera, show promise to provide higher counting efficiency and resolution, leading to better image quality, more patient comfort and potentially lower radiation exposure. While the focus has been on myocardial perfusion imaging with single-photon emission computed tomography, increased use of positron emission tomography is broadening the field to include molecular imaging of the myocardium and of the coronary vasculature. Further advances may require integrating cardiac nuclear cameras with other imaging devices, ie, hybrid imaging cameras. The goal is to image the heart and its physiological processes as accurately as possible, to prevent and cure disease processes.

  4. CCD Photometry of M15

    Science.gov (United States)

    Ruelas, A.; Sánchez, L. J.; Herrera, G.; Nigoche-Netro, A.

    2011-10-01

    We present CCD observations of the galactic globular cluster M15, in the B and V filters. The cluster was reasonably covered, except in its northern region where our observations present a gap. We obtained a Hertszprung-Russell (HR) diagram for each region observed, and later we produced a combined HR diagram containing more than 3000 stars. We generate a clean Colour Magnitude Diagram (CMD) and a Super Fiducial Line (SFL). Application of several methods and isochrone fitting leads us to obtain values for the metallicity [Fe/H]_{M15} ˜ -2.16±0.10, the reddening E(B-V)_{M15} ˜ 0.11±0.03, and a distance modulus of [(m-M)_0]_{M15}˜ 15.03.

  5. Design and development of guide vane cascade for a low speed number Francis turbine

    Institute of Scientific and Technical Information of China (English)

    Biraj Singh THAPA; Chirag TRIVEDI; Ole Gunnar DAHLHAUG

    2016-01-01

    Guide vane cascade of a low speed number Francis turbine is developed for the experimental investigations. The test setup is able to produce similar velocity distributions at the runner inlet as that of a reference prototype turbine. Standard analytical methods are used to design the reference turbine. Periodic walls of flow channel between guide vanes are identified as the starting profile for the boundary of the cascade. Two alternative designs with three guide vanes and two guide vanes, without runner, are studied. A new approach, for the hydraulic design and optimization of the cascade test setup layout, is proposed and investigated in details. CFD based optimization methods are used to define the final layout of the test setup. The optimum design is developed as a test setup and experimental validation is done with PIV methods. The optimized design of cascade with one guide vane between two flow channels is found to produce similar flow conditions to that in the runner inlet of a low speed number Francis turbine.

  6. Loss reduction in axial-flow compressors through low-speed model testing

    Science.gov (United States)

    Wisler, D. C.

    1984-01-01

    A systematic procedure for reducing losses in axial-flow compressors is presented. In this procedure, a large, low-speed, aerodynamic model of a high-speed core compressor is designed and fabricated based on aerodynamic similarity principles. This model is then tested at low speed where high-loss regions associated with three-dimensional endwall boundary layers flow separation, leakage, and secondary flows can be located, detailed measurements made, and loss mechanisms determined with much greater accuracy and much lower cost and risk than is possible in small, high-speed compressors. Design modifications are made by using custom-tailored airfoils and vector diagrams, airfoil endbends, and modified wall geometries in the high-loss regions. The design improvements resulting in reduced loss or increased stall margin are then scaled to high speed. This paper describes the procedure and presents experimental results to show that in some cases endwall loss has been reduced by as much as 10 percent, flow separation has been reduced or eliminated, and stall margin has been substantially improved by using these techniques.

  7. EXPERIMENTAL INVESTIGATION OF ROTATING STALL FOR A LOW-SPEED CENTRIFUGAL COMPRESSOR

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiaocheng; GUO Qiang; DU Zhaohui; CHEN Hua; ZHAO Yan

    2008-01-01

    Unsteady flows and rotating stall of a low-speed centrifugal compressor are investigated by measuring vaneless diffuser wall static pressure fluctuation and internal flow fields at different small flow fluxes. During the experiment, firstly the real time static pressure fluctuations on the vaneless diffuser shroud at different circumferential and radial position were acquired by high-frequency dynamic pressure transducers. Discrete Fourier transformation analysis and cross-correlation analysis were applied to the experimental results to ascertain the rotating stall beginning operation conditions and stall cells numbers and rotating speed. Secondly, the vaneless diffuser inlet flow angle distribution along diffuser width direction was acquired by single hotwire, which was compared with SENOO's analysis results. At last, the internal flow fields of the centrifugal compressor were investigated with a particle image velocimetry (PIV) system at different small flow fluxes. The flow field development of vaneless diffuser and blade flow passage are given at rotating stall conditions. The experiments enrich the understanding of rotating stall flow phenomenon of the low-speed centrifugal compressor and provide full experiment data for designing high performance centrifugal compressor.

  8. Electromyography responses of pediatric and young adult volunteers in low-speed frontal impacts.

    Science.gov (United States)

    Mathews, Emily A; Balasubramanian, Sriram; Seacrist, Thomas; Maltese, Matthew R; Sterner, Robert; Arbogast, Kristy B

    2013-10-01

    No electromyography (EMG) responses data exist of children exposed to dynamic impacts similar to automotive crashes, thereby, limiting active musculature representation in computational occupant biomechanics models. This study measured the surface EMG responses of three neck, one torso and one lower extremity muscles during low-speed frontal impact sled tests (average maximum acceleration: 3.8g; rise time: 58.2ms) performed on seated, restrained pediatric (n=11, 8-14years) and young adult (n=9, 18-30years) male subjects. The timing and magnitude of the EMG responses were compared between the two age groups. Two normalization techniques were separately implemented and evaluated: maximum voluntary EMG (MVE) and neck cross-sectional area (CSA). The MVE-normalized EMG data indicated a positive correlation with age in the rectus femoris for EMG latency; there was no correlation with age for peak EMG amplitudes for the evaluated muscles. The cervical paraspinous exhibited shorter latencies compared with the other muscles (2-143ms). Overall, the erector spinae and rectus femoris peak amplitudes were relatively small. Neck CSA-normalized peak EMG amplitudes negatively correlated with age for the cervical paraspinous and sternocleidomastoid. These data can be useful to incorporate active musculature in computational models, though it may not need to be age-specific in low-speed loading environments.

  9. Loss reduction in axial-flow compressors through low-speed model testing

    Science.gov (United States)

    Wisler, D. C.

    1984-01-01

    A systematic procedure for reducing losses in axial-flow compressors is presented. In this procedure, a large, low-speed, aerodynamic model of a high-speed core compressor is designed and fabricated based on aerodynamic similarity principles. This model is then tested at low speed where high-loss regions associated with three-dimensional endwall boundary layers flow separation, leakage, and secondary flows can be located, detailed measurements made, and loss mechanisms determined with much greater accuracy and much lower cost and risk than is possible in small, high-speed compressors. Design modifications are made by using custom-tailored airfoils and vector diagrams, airfoil endbends, and modified wall geometries in the high-loss regions. The design improvements resulting in reduced loss or increased stall margin are then scaled to high speed. This paper describes the procedure and presents experimental results to show that in some cases endwall loss has been reduced by as much as 10 percent, flow separation has been reduced or eliminated, and stall margin has been substantially improved by using these techniques.

  10. Characteristics and Performance of the CCD Photometric System at Lulin Observatory

    Institute of Scientific and Technical Information of China (English)

    Daisuke Kinoshita; Chin-Wei Chen; Hung-Chin Lin; Zhong-Yi Lin; Kui-Yun Huang; Yung-Shin Chang; Wen-Ping Chen

    2005-01-01

    The Lulin One-meter Telescope at Lulin Observatory in Taiwan started open-use observations in J anuary 2003. In order to evaluate the performance of the CCD photometric system, the characteristics and quality of the site, we obtained data of photometric standards as well as calibration data from February to November 2004. We report here the results of our analysis including the gain,readout noise, dark current and linearity of the CCD camera, and transformation coefficients, total throughputs, night sky brightnesses and limiting magnitudes for UBVRI bands.

  11. Design of high speed camera based on CMOS technology

    Science.gov (United States)

    Park, Sei-Hun; An, Jun-Sick; Oh, Tae-Seok; Kim, Il-Hwan

    2007-12-01

    The capacity of a high speed camera in taking high speed images has been evaluated using CMOS image sensors. There are 2 types of image sensors, namely, CCD and CMOS sensors. CMOS sensor consumes less power than CCD sensor and can take images more rapidly. High speed camera with built-in CMOS sensor is widely used in vehicle crash tests and airbag controls, golf training aids, and in bullet direction measurement in the military. The High Speed Camera System made in this study has the following components: CMOS image sensor that can take about 500 frames per second at a resolution of 1280*1024; FPGA and DDR2 memory that control the image sensor and save images; Camera Link Module that transmits saved data to PC; and RS-422 communication function that enables control of the camera from a PC.

  12. Robust and Stable Disturbance Observer of Servo System for Low Speed Operation Using the Radial Basis Function Network

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2005-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low speed operation is sensitive to the variation of machine parameter, especially the moment of inertia. To esti......A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low speed operation is sensitive to the variation of machine parameter, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable...

  13. Robotic CCD microscope for enhanced crystal recognition

    Science.gov (United States)

    Segelke, Brent W.; Toppani, Dominique

    2007-11-06

    A robotic CCD microscope and procedures to automate crystal recognition. The robotic CCD microscope and procedures enables more accurate crystal recognition, leading to fewer false negative and fewer false positives, and enable detection of smaller crystals compared to other methods available today.

  14. Status Of Sofradir IR-CCD Detectors

    Science.gov (United States)

    Tribolet, Philippe; Radisson, Patrick

    1988-05-01

    The topics of this paper deal with the IR-CCD detectors manufactured by SOFRADIR the new French joint venture. Description of the IRCCD technology and the advantages of this approach are given. In conclusion, some IR-CCD typical results are given.

  15. Unmanned Ground Vehicle Perception Using Thermal Infrared Cameras

    Science.gov (United States)

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

    2011-01-01

    TIR cameras can be used for day/night Unmanned Ground Vehicle (UGV) autonomous navigation when stealth is required. The quality of uncooled TIR cameras has significantly improved over the last decade, making them a viable option at low speed Limiting factors for stereo ranging with uncooled LWIR cameras are image blur and low texture scenes TIR perception capabilities JPL has explored includes: (1) single and dual band TIR terrain classification (2) obstacle detection (pedestrian, vehicle, tree trunks, ditches, and water) (3) perception thru obscurants

  16. Generation of atmospheric boundary layer in the IIUM low speed wind tunnel

    Science.gov (United States)

    Za'aba, Khalid Aldin Bin; Asrar, Waqar; Dheeb, Mohamad Al

    2017-03-01

    The purpose of this paper is to describe an attempt made to simulate the atmospheric boundary layer (ABL) in the Low Speed Wind Tunnel (LSWT) at IIUM. This was performed through modifications of the inlet and surface conditions of the test section. Devices such as spires, fences and surface roughness were used. The ASCE 7-10 standard was used as a reference to validate the results between the wind tunnel data and the full-scale ABL flow characteristics. The velocity profile and turbulence intensity were measured using a one-dimensional hotwire (CTA) probe. The data obtained show good agreement with ASCE 7-10 velocity profiles for exposures B and C while using a scale of 1:488 to match the wind tunnel data. The turbulence intensity profiles do not show a good agreement.

  17. Discrete unified gas kinetic scheme for all Knudsen number flows: low-speed isothermal case.

    Science.gov (United States)

    Guo, Zhaoli; Xu, Kun; Wang, Ruijie

    2013-09-01

    Based on the Boltzmann-BGK (Bhatnagar-Gross-Krook) equation, in this paper a discrete unified gas kinetic scheme (DUGKS) is developed for low-speed isothermal flows. The DUGKS is a finite-volume scheme with the discretization of particle velocity space. After the introduction of two auxiliary distribution functions with the inclusion of collision effect, the DUGKS becomes a fully explicit scheme for the update of distribution function. Furthermore, the scheme is an asymptotic preserving method, where the time step is only determined by the Courant-Friedricks-Lewy condition in the continuum limit. Numerical results demonstrate that accurate solutions in both continuum and rarefied flow regimes can be obtained from the current DUGKS. The comparison between the DUGKS and the well-defined lattice Boltzmann equation method (D2Q9) is presented as well.

  18. Heat transfer effects on the stability of low speed plane Couette-Poiseuille flow

    Energy Technology Data Exchange (ETDEWEB)

    Oezgen, Serkan [Middle East Technical University, Department of Aerospace Engineering, Ankara (Turkey); Dursunkaya, Zafer [Middle East Technical University, Department of Mechanical Engineering, Ankara (Turkey); Ebrinc, Ali A. [FORD Otosan, Kocaeli (Turkey)

    2007-10-15

    The stability problem of low-speed plane Couette-Poiseuille flow of air under heat transfer effects is solved numerically using the linear stability theory. Stability equations obtained from two-dimensional equations of motion and their boundary conditions result in an eigenvalue problem that is solved using an efficient shoot-search technique. Variable fluid properties are accounted for both in the basic flow and the perturbation (stability) equations. A parametric study is performed in order to assess the roles of moving wall velocity and heat transfer. It is found that the moving wall velocity and the location of the critical layers play decisive roles in the instability mechanism. The flow becomes unconditionally stable whenever the moving wall velocity exceeds half of the maximum velocity in the channel. With wall heating and Mach number effects included, the flow is stabilized. (orig.)

  19. 9- by 15-Foot Low Speed Wind Tunnel Acoustic Improvements Expanded Overview

    Science.gov (United States)

    Stephens, David

    2016-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn Research Center was built in 1969 in the return leg of the 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT). The 8x6 SWT was completed in 1949 and acoustically treated to mitigate community noise issues in 1950. This treatment included the addition of a large muffler downstream of the 8x6 SWT test section and diffuser. The 9x15 LSWT was designed for performance testing of V/STOL aircraft models, but with the addition of the current acoustic treatment in 1986 the tunnel been used principally for acoustic and performance testing of aircraft propulsion systems. The present document describes an anticipated acoustic upgrade to be completed in 2017.

  20. Development of Delta Wing Aerodynamics Research in Universiti Teknologi Malaysia Low Speed Wind Tunnel

    Directory of Open Access Journals (Sweden)

    Shabudin Mat

    2014-07-01

    Full Text Available This paper presents wind tunnel experiment on two delta wing configurations which are differentiated by their leading edge profiles: sharp and round-edged wings. The experiments were performed as a part of the delta wing aerodynamics research development in Universiti Teknologi Malaysia, low speed tunnel (UTM-LST. Steady load balance and flow visualization tests were conducted at Reynolds numbers of 0.5, 1, and 1.5 × 106, respectively. The flow measurement at low Reynolds number was also performed at as low as speed of 5 m/s. During the experiments, laser with smoke flow visualizations test was performed on both wings. The study has identified interesting features of the interrelationship between the conventional leading edge primary vortex and the occurrence and development of the vortex breakdown above the delta wings. The results conclude the vortex characteristics are largely dependent on the Reynolds number, angle of attack, and leading-edge radii of the wing.

  1. Numerical Simulation of a Complete Low-Speed Wind Tunnel Circuit

    Science.gov (United States)

    Nayani, Sudheer N.; Sellers, William L., III; Tinetti, Ana F.; Brynildsen, Scott E.; Walker, Eric L.

    2016-01-01

    A numerical simulation of the complete circuit of the NASA Langley 14 x 22-ft low-speed wind tunnel is described. Inside the circuit, all turning vanes are modeled as well as the five flow control vanes downstream of the 1st corner. The fan drive system is modeled using an actuator disk for the fan blades coupled with the fan nacelle. All the surfaces are modeled as viscous walls except the turning vanes, which were modeled as inviscid surfaces. NASA Langley's TetrUSS unstructured grid software was used for grid generation and flow simulation. Two turbulence models were employed in the present study, namely, the one-equation Spalart-Allmaras model and the shear stress transport (SST) model of Menter. The paper shows the flow characteristics in the circuit and compares the results with experimental data where available.

  2. The application of the SAUNA CFD system to high and low speed vehicles

    Science.gov (United States)

    May, Nicholas E.; Peace, Andrew J.; Shaw, Jonathon A.

    1994-04-01

    The SAUNA grid generation and flow simulation system is applied to a variety of vehicles flows. The basic features and problems associated with predicting high speed external flows are discussed and contrasted with those associated with typical internal flows. Particular attention is paid in the discussion to turbulence modelling requirements. General descriptions of the grid generation philosophy adopted within the SAUNA system (structured, unstructured, hybrid) and the flow solution methodology are given. It is explained how the compressible flow algorithm may be modified to enable efficient calculation of low speed flows, thus extending the range of application of the SAUNA system to include conventional ground and sea vehicles. The grid generation capabilities of SAUNA are illustrated by showing examples of grids generated around configurations of a complete aircraft, a submarine and an automobile. The flow simulations are evaluated by comparison with experiment for several external high speed flows and a lower speed internal flow.

  3. High-resolution methods for incompressible and low-speed flows

    CERN Document Server

    Drikakis, Dimitris

    2006-01-01

    This book covers the basic techniques for simulating incompressible and low-speed flows with high fidelity in conjunction with high-resolution methods. This includes techniques for steady and unsteady flows with high-order time integration and multigrid methods, as well as specific issues associated with interfacial and turbulent flows. The book is addressed to a broad readership, including engineers and scientists concerned with the development or application of computational methods for fluid flow problems in: Mechanical, Aerospace, Civil and Chemical Engineering, Biological Flows, Atmospheric and Oceanographic Applications as well as other Environmental disciplines. It can be used for teaching postgraduate courses on Computational Fluid Dynamics and Numerical Methods in Engineering and Applied Mathematics, and can also be used as a complementary textbook in undergraduate CFD courses.

  4. Impact characteristics of a vehicle population in low speed front to rear collisions.

    Science.gov (United States)

    Nishimura, Naoya; Simms, Ciaran K; Wood, Denis P

    2015-06-01

    Rear impact collisions are mostly low severity, but carry a very high societal cost due to reported symptoms of whiplash and related soft tissue injuries. Given the difficulty in physiological measurement of damage in whiplash patients, there is a significant need to assess rear impact severity on the basis of vehicle damage. This paper presents fundamental impact equations on the basis of an equivalent single vehicle to rigid barrier collision in order to predict relationships between impact speed, maximum dynamic crush, mean and peak acceleration, time to common velocity and vehicle stiffness. These are then applied in regression analysis of published staged low speed rear impact tests. The equivalent mean and peak accelerations are linear functions of the collision closing speed, while the time to common velocity is independent of the collision closing speed. Furthermore, the time to common velocity can be used as a surrogate measure of the normalized vehicle stiffness, which provides opportunity for future accident reconstruction.

  5. Aeroacoustic response of coaxial wall-mounted Helmholtz resonators in a low-speed wind tunnel.

    Science.gov (United States)

    Slaton, William V; Nishikawa, Asami

    2015-01-01

    The aeroacoustic response of coaxial wall-mounted Helmholtz resonators with different neck geometries in a low-speed wind tunnel has been investigated. Experimental test results of this system reveal a strong aeroacoustic response over a Strouhal number range of 0.25 to 0.1 for both increasing and decreasing the flow rate in the wind tunnel. Aeroacoustic response in the low-amplitude range O(10(-3)) < Vac/Vflow < O(10(-1)) has been successfully modeled by describing-function analysis. This analysis, coupled with a turbulent flow velocity distribution model, gives reasonable values for the location in the flow of the undulating stream velocity that drives vortex shedding at the resonator mouth. Having an estimate for the stream velocity that drives the flow-excited resonance is crucial when employing the describing-function analysis to predict aeroacoustic response of resonators.

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

    Science.gov (United States)

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

    2015-01-01

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

  7. Development of a fast readout system of an X-ray CCD

    CERN Document Server

    Awaki, H; Koyama, K; Tomida, H; Tsuru, T

    1999-01-01

    In the course of developing a fast readout system of an X-ray CCD camera with low noise using HPK-CCD, we have succeeded in making a clock generator to read data from a CCD with the speed of 2 Mpixel/s. This generator is fabricated from commercially available products in order to simplify the manufacturing procedure. To determine the noise of the system, we are evaluating the noise from each part which conceivably contributes. It is known that the readout noise depends on the clock speed. Thus, to begin with, we measured the dependency of the system noise from the ADC in the data acquisition system on its clock speed.

  8. 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.

  9. Scintillating track image camera-SCITIC

    CERN Document Server

    Sato, Akira; Ieiri, Masaharu; Iwata, Soma; Kadowaki, Tetsuhito; Kurosawa, Maki; Nagae, Tomohumi; Nakai, Kozi

    2004-01-01

    A new type of track detector, scintillating track image camera (SCITIC) has been developed. Scintillating track images of particles in a scintillator are focused by an optical lens system on a photocathode on image intesifier tube (IIT). The image signals are amplified by an IIT-cascade and stored by a CCD camera. The performance of the detector has been tested with cosmic-ray muons and with pion- and proton-beams from the KEK 12-GeV proton synchrotron. Data of the test experiments have shown promising features of SCITIC as a triggerable track detector with a variety of possibilities. 7 Refs.

  10. High-performance digital color video camera

    Science.gov (United States)

    Parulski, Kenneth A.; D'Luna, Lionel J.; Benamati, Brian L.; Shelley, Paul R.

    1992-01-01

    Typical one-chip color cameras use analog video processing circuits. An improved digital camera architecture has been developed using a dual-slope A/D conversion technique and two full-custom CMOS digital video processing integrated circuits, the color filter array (CFA) processor and the RGB postprocessor. The system used a 768 X 484 active element interline transfer CCD with a new field-staggered 3G color filter pattern and a lenslet overlay, which doubles the sensitivity of the camera. The industrial-quality digital camera design offers improved image quality, reliability, manufacturability, while meeting aggressive size, power, and cost constraints. The CFA processor digital VLSI chip includes color filter interpolation processing, an optical black clamp, defect correction, white balance, and gain control. The RGB postprocessor digital integrated circuit includes a color correction matrix, gamma correction, 2D edge enhancement, and circuits to control the black balance, lens aperture, and focus.

  11. Is Flat fielding Safe for Precision CCD Astronomy?

    Science.gov (United States)

    Baumer, Michael; Davis, Christopher P.; Roodman, Aaron

    2017-08-01

    The ambitious goals of precision cosmology with wide-field optical surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST) demand precision CCD astronomy as their foundation. This in turn requires an understanding of previously uncharacterized sources of systematic error in CCD sensors, many of which manifest themselves as static effective variations in pixel area. Such variation renders a critical assumption behind the traditional procedure of flat fielding—that a sensor’s pixels comprise a uniform grid—invalid. In this work, we present a method to infer a curl-free model of a sensor’s underlying pixel grid from flat-field images, incorporating the superposition of all electrostatic sensor effects—both known and unknown—present in flat-field data. We use these pixel grid models to estimate the overall impact of sensor systematics on photometry, astrometry, and PSF shape measurements in a representative sensor from the Dark Energy Camera (DECam) and a prototype LSST sensor. Applying the method to DECam data recovers known significant sensor effects for which corrections are currently being developed within DES. For an LSST prototype CCD with pixel-response non-uniformity (PRNU) of 0.4%, we find the impact of “improper” flat fielding on these observables is negligible in nominal .7″ seeing conditions. These errors scale linearly with the PRNU, so for future LSST production sensors, which may have larger PRNU, our method provides a way to assess whether pixel-level calibration beyond flat fielding will be required.

  12. The second US Naval Observatory CCD Astrograph Catalog (UCAC2)

    CERN Document Server

    Zacharias, N; Zacharias, M I; Wycoff, G L; Hall, D M; Monet, D G; Rafferty, T J

    2004-01-01

    The second USNO CCD Astrograph Catalog, UCAC2 was released in July 2003. Positions and proper motions for 48,330,571 sources (mostly stars) are available on 3 CDs, supplemented with 2MASS photometry for 99.5% of the sources. The catalog covers the sky area from -90 to +40 degrees declination, going up to +52 in some areas; this completely supersedes the UCAC1 released in 2001. Current epoch positions are obtained from observations with the USNO 8-inch Twin Astrograph equipped with a 4k CCD camera. The precision of the positions are 15 to 70 mas, depending on magnitude, with estimated systematic errors of 10 mas or below. Proper motions are derived by utilizing over 140 ground-and space-based catalogs, including Hipparcos/Tycho, the AC2000.2, as well as yet unpublished re-measures of the AGK2 plates and scans from the NPM and SPM plates. Proper motion errors are about 1 to 3 mas/yr for stars to 12th magnitude, and about 4 to 7 mas/yr for fainter stars to 16th magnitude. The observational data, astrometric redu...

  13. Study of the post-derailment safety measures on low-speed derailment tests

    Science.gov (United States)

    Guo, Lirong; Wang, Kaiyun; Lin, Jianhui; Zhang, Bing; Chen, Zaigang; Song, Xinwu; Du, Gaofeng

    2016-07-01

    Prevention of train from derailment is the most important issue for the railway system. Keeping derailed vehicle close to the track centreline is beneficial to minimise the severe consequences associated with derailments. In this paper, the post-derailment safety measures are studied based on low-speed derailment tests. Post-derailment devices can prevent deviation of the train from the rail by catching the rail, and they are mounted under the axle box. Considering the different structures of vehicles, both trailer and motor vehicles are equipped with the safety device and then separately used in low-speed derailment tests. In derailment tests, two kinds of track, namely the CRTS-I slab ballastless track and the CRTS-II bi-block sleeper ballastless track, are adopted to investigate the effect of the track types on the derailment. In addition, the derailment speed and the weight of the derailed vehicle are also taken into account in derailment tests. The test results indicate that the post-derailment movement of the vehicle includes running and bounce. Reducing the derailment speed and increasing the weight of the head of the train are helpful to reduce the possibility for derailments. For the CRTS-I slab ballastless track, the safety device can prevent trailer vehicles from deviating from the track centreline. The gearbox plays an important role in controlling the lateral displacement of motor vehicle after a derailment while the safety device contributes less to keep derailed motor vehicles on the track centreline. The lateral distance between the safety device and rails should be larger than 181.5 mm for protecting the fasteners system. And for the CRTS-II bi-block sleeper ballastless track, it helps to decrease the post-derailment distance due to the longitudinal impacts with sleepers. It can also restrict the lateral movement of derailed vehicle due to the high shoulders. The results suggest that, CRTS-II bi-block sleeper ballastless track should be widely used

  14. Chebyshev collocation spectral lattice Boltzmann method for simulation of low-speed flows.

    Science.gov (United States)

    Hejranfar, Kazem; Hajihassanpour, Mahya

    2015-01-01

    In this study, the Chebyshev collocation spectral lattice Boltzmann method (CCSLBM) is developed and assessed for the computation of low-speed flows. Both steady and unsteady flows are considered here. The discrete Boltzmann equation with the Bhatnagar-Gross-Krook approximation based on the pressure distribution function is considered and the space discretization is performed by the Chebyshev collocation spectral method to achieve a highly accurate flow solver. To provide accurate unsteady solutions, the time integration of the temporal term in the lattice Boltzmann equation is made by the fourth-order Runge-Kutta scheme. To achieve numerical stability and accuracy, physical boundary conditions based on the spectral solution of the governing equations implemented on the boundaries are used. An iterative procedure is applied to provide consistent initial conditions for the distribution function and the pressure field for the simulation of unsteady flows. The main advantage of using the CCSLBM over other high-order accurate lattice Boltzmann method (LBM)-based flow solvers is the decay of the error at exponential rather than at polynomial rates. Note also that the CCSLBM applied does not need any numerical dissipation or filtering for the solution to be stable, leading to highly accurate solutions. Three two-dimensional (2D) test cases are simulated herein that are a regularized cavity, the Taylor vortex problem, and doubly periodic shear layers. The results obtained for these test cases are thoroughly compared with the analytical and available numerical results and show excellent agreement. The computational efficiency of the proposed solution methodology based on the CCSLBM is also examined by comparison with those of the standard streaming-collision (classical) LBM and two finite-difference LBM solvers. The study indicates that the CCSLBM provides more accurate and efficient solutions than these LBM solvers in terms of CPU and memory usage and an exponential

  15. e2v CCD and CMOS sensors and systems designed for astronomical applications

    Science.gov (United States)

    Jorden, Paul; Jerram, Paul; Jordan, Douglas; Pratlong, Jérôme; Robbins, Mark

    2016-08-01

    e2v continues to evolve its product range of sensors and systems, with CCD and CMOS sensors. We describe recent developments of high performance image sensors and precision system components. Several low noise backthinned CMOS sensors have been developed for scientific applications. CCDs have become larger whilst retaining very low noise and high quantum efficiency. Examples of sensors and sub-systems are presented including the recently completed 1.2 GigaPixel J-PAS cryogenic camera.

  16. Investigation of Load and Pressure Distribution onWing with Wake Rollup for Low Speed Aircraft

    Directory of Open Access Journals (Sweden)

    Laith W. Ismail

    2008-01-01

    Full Text Available The presented work shows a preliminary analytic method for estimation of load and pressure distributions on low speed wings with flow separation and wake rollup phenomena’s. A higher order vortex panel method is coupled with the numerical lifting line theory by means of iterative procedure including models of separation and wake rollup. The computer programs are written in FORTRAN which are stable and efficient. The capability of the present method is investigated through a number of test cases with different types of wing sections (NACA 0012 and GA(W-1 for different aspect ratios and angles of attack, the results include the lift and drag curves, lift and pressure distributions along the wing span taking into the consideration the effect of the angles of attack and the aspect ratios on the wake rollup. The pressure distribution on the wings shows that there is a region of constant pressure on the upper surface of the wings near the trailing edge in the middle of the wing, also there is a region of flow separation on the upper surface of the wings. A good agreement is found between the presented work results and other from previous researches. These results show that the presented method is able to capture much of flow over wings feature like separation and wake rollup.

  17. Numerical Simulation of Combustion and Extinction of a Solid Cylinder in Low-Speed Cross Flow

    Science.gov (United States)

    Tien, J. S.; Yang, Chin Tien

    1998-01-01

    The combustion and extinction behavior of a diffusion flame around a solid fuel cylinder (PMMA) in low-speed forced flow in zero gravity was studied numerically using a quasi-steady gas phase model. This model includes two-dimensional continuity, full Navier Stokes' momentum, energy, and species equations with a one-step overall chemical reaction and second-order finite-rate Arrhenius kinetics. Surface radiation and Arrhenius pyrolysis kinetics are included on the solid fuel surface description and a parameter Phi, representing the percentage of gas-phase conductive heat flux going into the solid, is introduced into the interfacial energy balance boundary condition to complete the description for the quasi-steady gas-phase system. The model was solved numerically using a body-fitted coordinate transformation and the SIMPLE algorithm. The effects of varying freestream velocity and Phi were studied. These parameters have a significant effect on the flame structure and extinction limits. Two flame modes were identified: envelope flame and wake flame. Two kinds of flammability limits were found: quenching at low-flow speeds due to radiative loss and blow-off at high flow speeds due to insufficient gas residence time. A flammability map was constructed showing the existence of maximum Phi above which the solid is not flammable at any freestream velocity.

  18. Small Propeller and Rotor Testing Capabilities of the NASA Langley Low Speed Aeroacoustic Wind Tunnel

    Science.gov (United States)

    Zawodny, Nikolas S.; Haskin, Henry H.

    2017-01-01

    The Low Speed Aeroacoustic Wind Tunnel (LSAWT) at NASA Langley Research Center has recently undergone a configuration change. This change incorporates an inlet nozzle extension meant to serve the dual purposes of achieving lower free-stream velocities as well as a larger core flow region. The LSAWT, part of the NASA Langley Jet Noise Laboratory, had historically been utilized to simulate realistic forward flight conditions of commercial and military aircraft engines in an anechoic environment. The facility was modified starting in 2016 in order to expand its capabilities for the aerodynamic and acoustic testing of small propeller and unmanned aircraft system (UAS) rotor configurations. This paper describes the modifications made to the facility, its current aerodynamic and acoustic capabilities, the propeller and UAS rotor-vehicle configurations to be tested, and some preliminary predictions and experimental data for isolated propeller and UAS rotor con figurations, respectively. Isolated propeller simulations have been performed spanning a range of advance ratios to identify the theoretical propeller operational limits of the LSAWT. Performance and acoustic measurements of an isolated UAS rotor in hover conditions are found to compare favorably with previously measured data in an anechoic chamber and blade element-based acoustic predictions.

  19. Vortex/Body Interaction and Sound Generation in Low-Speed Flow

    Science.gov (United States)

    Kao, Hsiao C.

    1998-01-01

    The problem of sound generation by vortices interacting with an arbitrary body in a low-speed flow has been investigated by the method of matched asymptotic expansions. For the purpose of this report, it is convenient to divide the problem into three parts. In the first part the mechanism of the vortex/body interaction, which is essentially the inner solution in the inner region, is examined. The trajectories for a system of vortices rotating about their centroid are found to undergo enormous changes after interaction; from this, some interesting properties emerged. In the second part, the problem is formulated, the outer solution is found, matching is implemented, and solutions for acoustic pressure are obtained. In the third part, Fourier integrals are evaluated and predicated results presented. An examination of these results reveals the following: (a) the background noise can be either augmented or attenuated by a body after interaction, (b) sound generated by vortex/body interaction obeys a scaling factor, (C) sound intensity can be reduced substantially by positioning the vortex system in the "favorable" side of the body instead of the "unfavorable" side, and (d) acoustic radiation from vortex/bluff-body interaction is less than that from vortex/airfoil interaction under most circumstances.

  20. Low-speed aerodynamic characteristics of a powered NASP-like configuration in ground effect

    Science.gov (United States)

    Gatlin, Gregory M.

    1989-01-01

    Results are presented on the low-speed aerodynamic characteristics of a simplified NASP (for National Aerospace Plane Program)-like configuration, obtained in the NASA-Langley 14-by-22-foot subsonic tunnel. The model consisted of a triangular wedge forebody, a rectangular midsection housing the propulsion simulation system, and a rectangular wedge aftbody; it also included a delta wing, exhaust flow deflectors, and aftbody fences. Flow visualization was obtained by injecting water into the engine simulator inlets and using a laser light sheet to illuminate the resulting exhaust flow. It was found that power-on ground effects for NASP-like configuration can be substantial; these effects can be reduced by increasing the angle-of-attack to the value of the aftbody ramp angle. Power-on lift losses in ground effect increased with increasing thrust, but could be reduced by the addition of a delta wing to the configuration. Power-on lift losses also increased with use of aftbody fences.

  1. Analysis of Low Speed Stall Aerodynamics of a Swept Wing with Laminar Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  2. Analysis of Low-Speed Stall Aerodynamics of a Swept Wing with Laminar-Flow Glove

    Science.gov (United States)

    Bui, Trong T.

    2014-01-01

    Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) analysis was conducted to study the low-speed stall aerodynamics of a GIII aircraft's swept wing modified with a laminar-flow wing glove. The stall aerodynamics of the gloved wing were analyzed and compared with the unmodified wing for the flight speed of 120 knots and altitude of 2300 ft above mean sea level (MSL). The Star-CCM+ polyhedral unstructured CFD code was first validated for wing stall predictions using the wing-body geometry from the First American Institute of Aeronautics and Astronautics (AIAA) CFD High-Lift Prediction Workshop. It was found that the Star-CCM+ CFD code can produce results that are within the scattering of other CFD codes considered at the workshop. In particular, the Star-CCM+ CFD code was able to predict wing stall for the AIAA wing-body geometry to within 1 degree of angle of attack as compared to benchmark wind-tunnel test data. Current results show that the addition of the laminar-flow wing glove causes the gloved wing to stall much earlier than the unmodified wing. Furthermore, the gloved wing has a different stall characteristic than the clean wing, with no sharp lift drop-off at stall for the gloved wing.

  3. Optimizing Low Speed VoIP Network for Rural Next Generation Network (R-NGN

    Directory of Open Access Journals (Sweden)

    Yoanes Bandung

    2007-11-01

    Full Text Available In this research, we propose an optimization method based-on E-Model for designing an efficient low speed VoIP network for Rural Next Generation Network (R-NGN. We are choosing 128 kbps and 256 kbps bandwidth as the typical community link to be used in the designing of R-NGN infrastructure. The method is based on selection of some VoIP network parameters such as voice coder, communication protocol, packet loss level, network utilization and resource allocation. We draw analytic approach for achieving rating value (R of E-model that represent level of quality of service. In this approach, we focus on delay and packet loss calculation to find the rating value. We state the rating value = 70 as minimum level of quality of service for each call, equivalent to 3.6 of Mean Opinion Score (MOS. In our experiments, either G.723.1 5.3 kbps or G.729 is chosen for maximizing the number of VoIP calls, it depends on link utilization and level of packet loss.

  4. Experimental Research on an Active Sting Damper in a Low Speed Acoustic Wind Tunnel

    Directory of Open Access Journals (Sweden)

    Jinjin Chen

    2014-01-01

    Full Text Available Wind tunnels usually use long cantilever stings to support aerodynamic models in order to reduce support system flow interference on experimental data. However, such support systems are a potential source of vibration problems which limit the test envelope and affect data quality due to the inherently low structural damping of the systems. When exposed to tunnel flow, turbulence and model flow separation excite resonant Eigenmodes of a sting structure causing large vibrations due to low damping. This paper details the development and experimental evaluation of an active damping system using piezoelectric devices with balance signal feedback both in a lab and a low speed acoustic wind tunnel and presents the control algorithm verification tests with a simple cantilever beam. It is shown that the active damper, controlled separately by both PID and BP neural network, has effectively attenuated the vibration. For sting mode only, 95% reduction of displacement response under exciter stimulation and 98% energy elimination of sting mode frequency have been achieved.

  5. Testing of Lightweight Fuel Cell Vehicles System at Low Speeds with Energy Efficiency Analysis

    Science.gov (United States)

    Mustaffa, Muhammad Rizuwan B.; Mohamed, Wan Ahmad Najmi B. Wan

    2013-12-01

    A fuel cell vehicle power train mini test bench was developed which consists of a 1 kW open cathode hydrogen fuel cell, electric motor, wheel, gearing system, DC/DC converter and vehicle control system (VCS). Energy efficiency identification and energy flow evaluation is a useful tool in identifying a detail performance of each component and sub-systems in a fuel cell vehicle system configuration. Three artificial traction loads was simulated at 30 kg, 40 kg and 50 kg force on a single wheel drive configuration. The wheel speed range reported here covers from idle to 16 km/h (low speed range) as a preliminary input in the research work frame. The test result shows that the system efficiency is 84.5 percent when the energy flow is considered from the fuel cell to the wheel and 279 watts of electrical power was produced by the fuel cell during that time. Dynamic system responses was also identified as the load increases beyond the motor traction capabilities where the losses at the converter and motor controller increased significantly as it tries to meet the motor traction power demands. This work is currently being further expanded within the work frame of developing a road-worthy fuel cell vehicle.

  6. Experiment about Drag Reduction of Bionic Non-smooth Surface in Low Speed Wind Tunnel

    Institute of Scientific and Technical Information of China (English)

    Tian Li-mei; Ren Lu-quan; Han Zhi-wu; Zhang Shi-cun

    2005-01-01

    The body surface of some organisms has non-smooth structure, which is related to drag reduction in moving fluid. To imitate these structures, models with a non-smooth surface were made. In order to find a relationship be tween drag reduction and the non-smooth surface, an orthogonal design test was employed in a low speed wind tunnel. Six factors likely to influence drag reduction were considered, and each factor tested at three levels. The six factors were the configuration, diameter/bottom width, height/depth, distribution, the arrangement of the rough structures on the experimental model and the wind speed. It was shown that the non-smooth surface causes drag reduction and the distribution of non-smooth structures on the model, and wind speed, are the predominant factors affecting drag reduction. Using analysis of variance, the optimal combination and levels were obtained, which were a wind speed of 44 m/s, distribution of the non-smooth structure on the tail of the experimental model, the configuration of riblets, diameter/bottom width of 1 mm, height/depth of 0.5 mm, arranged in a rhombic formation. At the optimal combination mentioned above, the 99% confidence interval for drag reduction was 11.13 % to 22.30%.

  7. Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

    Science.gov (United States)

    Kottapalli, Sesi B. R.

    2010-01-01

    Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

  8. Economics of industrial cogeneration with a residual-oil-fired low-speed diesel

    Energy Technology Data Exchange (ETDEWEB)

    Santini, D.J.; Belak, F.J.; Bernard, M.J.; Stodolsky, F.; Suchy, K.W.

    1984-01-01

    The only residual-oil-fired low speed diesel cogeneration facility in the US has been in operation for a year at the Hoffman-LaRoche Vitamin C plant in Belvidere, NJ. Operating data for this grid-connected 23 MW facility are used to construct a generic evaluation of the economic desirability of such systems for industrial electric/thermal applications and industrial-thermal/commercial-electrical applications made possible by recent US legislation (PURPA). The post 1980 changes in relative electrical and residual oil prices are shown to have made oil fired on-site generation more attractive. The likely 1985-2005 movements of electricity and residual oil prices are discussed, along with risks of error in projections. The system is evaluated as a whole and on an incremental basis. Incremental analysis includes (1) the economics of steam and hot water use given the diesel and (2) the economics of system generation given industrial electric, steam and hot water loads. The sensitivity of the economics of the system to the full range of US electricity and residual oil prices is estimated. The effect of variation in system loads is examined. The economic desirability of the system is often great but is also highly variable geographically, largely as a function of local evaded electricity charges.

  9. Oscillatory Behavior of an Arc Airfoil in Low-Speed Airflow

    Science.gov (United States)

    Molki, Majid; Sattari, Negin

    2011-11-01

    A computational investigation is conducted to study the oscillatory behavior of an arc airfoil situated in low-speed airflow. The present work is relevant to situations where the conventional rigid airfoils do not apply, such as the flight of bats. The outcome of this study is also beneficial in the design of micro air vehicles with flexible wings. The computations are performed using a deforming mesh to accommodate the airfoil oscillations. An unsteady, spatially second-order algorithm is employed to capture the time-variations of the lift and drag coefficients. A key feature of the present work is the flow response to airfoil oscillations. Fast Fourier Transform was applied to various parameters of the flow. For certain values of angle of attack for the non-oscillating airfoil, the flow has a dominant frequency and a well-defined vortex shedding. For other values of angle of attack, the flow around the non-oscillating airfoil contains many frequencies and has complex vortical structures. However, the oscillating airfoil in all cases makes the flow field periodic with well-defined patterns of vortex shedding. In this work, the flux of vorticity from the airfoil surface into the airflow is computed and compared with the pressure gradient along the surface of the airfoil. Effects of oscillations on magnitude and behavior of aerodynamic forces are also studied.

  10. Measurement and analysis of radiated sound from a low speed fan with a large tip gap.

    Science.gov (United States)

    Bilka, M J; Anthoine, J; Schram, C

    2014-05-01

    The wake flow field and radiated sound from a low speed axial fan is studied experimentally. The fan geometry uses controlled diffusion blades and is designed with a low aspect ratio (0.9). The fan is installed with a large tip gap, approximately 10% of the blade span. The radiated sound field is analyzed using a known trailing edge noise formulation. First, the model is compared to an experiment of a single airfoil in a wind tunnel to assess the predictive capabilities. Second, measurements of the fan are made at two different blade loading conditions. Hot wire measurements are made in the near wake of the fan to assess the extent of the tip leakage flow for each condition. The radiated sound fields are compared with the trailing edge noise theory. Use is made of the wake measurements as an input to a surface pressure model. When the fan is operated with the optimal blade loading, the influence of the tip leakage flow is found to be of secondary acoustic impact. When the fan is operated at a high loading condition for the blades, a more significant leakage flow develops and is found to be responsible for the dominant radiated sound.

  11. Sub-harmonic broadband humps and tip noise in low-speed ring fans.

    Science.gov (United States)

    Moreau, Stéphane; Sanjose, Marlène

    2016-01-01

    A joint experimental and numerical study has been achieved on a low-speed axial ring fan in clean inflow. Experimental evidence shows large periodic broadband humps at lower frequencies than the blade passing frequencies and harmonics even at design conditions. These sub-harmonic humps are also found to be sensitive to the fan process and consequently to its tip geometry. Softer fans yield more intense humps more shifted to lower frequencies with respect to the fan harmonics. Unsteady turbulent flow simulations of this ring fan mounted on a test plenum have been achieved by four different methods that have been validated by comparing with overall performances and detailed hot-wire velocity measurements in the wake. Noise predictions are either obtained directly or are obtained through Ffowcs Williams and Hawkings' analogy, and compared with narrowband and third-octave power spectra. All unsteady simulations correctly capture the low flow rates, the coherent vortex dynamics in the tip clearance and consequently the noise radiation dominated by the tip noise in the low- to mid-frequency range. Yet, only the scale-adaptive simulation and the lattice Boltzmann method simulations which can describe most of the turbulent structures accurately provide the proper spectral shape and levels, and consequently the overall sound power level.

  12. The Response of a Low Speed Compressor on Rotating Inlet Distortion

    Institute of Scientific and Technical Information of China (English)

    Chaoqun NIE; Jingxuan ZHANG; Zhiting TONG; Hongwu ZHANG

    2006-01-01

    In multi-spool engines,the downstream compressor experiences a rotating inlet distortion if rotating stall occurs in upstream compressor,which may induce the instability of the whole compressor.In this paper,the compressor dynamic behavior is the major focus.The experiment was carried out on a single-stage low-speed axial-flow compressor.A rotating distortion generator equipped with different distortion sector(s) was designed to produce different rotating inlet distortion clockwise or counterclockwise with up to 100% of the compressor design speed.The distortion sector can be installed single or in some combination such as four sectors together.Three types of distortion sector/combination are used in the research work,which are single 30 degree sector,four 30 degree sectors and single 120 degree sector.It is found that the total pressure loss caused by rotating sector(s) increases when the distortion speed rises.For co-rotating distortions,all the three types of inlet distortion exhibited a peak in stall margin degradation when the distortion speed corresponded to roughly 50% of rotor speed.The two-dimensional numerical simulations of the compressor flow field clearly show the propagation of the disturbances trigged by the distortion sector(s).

  13. Risk Factors Associated with Injury and Mortality from Paediatric Low Speed Vehicle Incidents: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Anne Paul Anthikkat

    2013-01-01

    Full Text Available Objective. This study reviews modifiable risk factors associated with fatal and nonfatal injury from low-speed vehicle runover (LSVRO incidents involving children aged 0–15 years. Data Sources. Electronic searches for child pedestrian and driveway injuries from the peer-reviewed literature and transport-related websites from 1955 to 2012. Study Selection. 41 studies met the study inclusion criteria. Data Extraction. A systematic narrative summary was conducted that included study design, methodology, risk factors, and other study variables. Results. The most commonly reported risk factors for LSVRO incidents included age under 5 years, male gender, and reversing vehicles. The majority of reported incidents involved residential driveways, but several studies identified other traffic and nontraffic locations. Low socioeconomic status and rental accommodation were also associated with LSVRO injury. Vehicles were most commonly driven by a family member, predominantly a parent. Conclusion. There are a number of modifiable vehicular, environmental, and behavioural factors associated with LSVRO injuries in young children that have been identified in the literature to date. Strategies relating to vehicle design (devices for increased rearward visibility and crash avoidance systems, housing design (physical separation of driveway and play areas, and behaviour (driver behaviour, supervision of young children are discussed.

  14. Impact force of a low speed water droplet colliding on a solid surface

    Science.gov (United States)

    Li, Jingyin; Zhang, Bin; Guo, Penghua; Lv, Qian

    2014-12-01

    The impact forces of the low-speed water droplet colliding on a light and tiny aluminum plate were measured by using a highly sensitive piezoelectric force transducer. The one-degree freedom vibration model was employed to analyze the oscillation of the measured force signals, and the plate vibration was confirmed as the cause through elaborately designed experiments. The force data were obtained by using the low-pass Finite Impulse Response filter and was verified to be reliable. The effects of impact velocity and diameter of droplets on the impact force evolutions and peak forces were investigated. The results revealed that the impact process of a liquid droplet is quite different from that of a solid ball in the frequency spectrum and in the power function of the peak force. The droplet impact is closer to a plastic impact, while the other behaves more nearly an elastic impact. The influence of droplet size on erosion is dependent on the impact time duration, which increases with droplet diameter. On the other hand, the impact pressure is the main cause of the material erosion when impact velocity is taken as the influence factor.

  15. Comparison of Wind Power Converter Reliability with Low-Speed and Medium-Speed Permanent-Magnet Synchronous Generators

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Franke, Toke

    2015-01-01

    of the low-speed (direct-drive) and medium-speed (one-stage) permanent-magnet synchronous generators are both promising solutions. This paper will assess and compare the reliability metrics for the machine-side converter for those two configurations. First, a translation from the mission profile......, according to the lifetime power cycles, the lifespan can be calculated when operating in various wind classes. It is concluded that, although the low-speed permanent-magnet synchronous generator is able to eliminate the gearbox, the lifespan of its machine-side converter is lower than the one-stage medium...

  16. Measurements of the tip-gap turbulent flow structure in a low-speed compressor cascade

    Science.gov (United States)

    Tang, Genglin

    This dissertation presents results from a thorough study of the tip-gap turbulent flow structure in a low-speed linear compressor cascade wind tunnel at Virginia Tech that includes a moving belt system to simulate the relative motion between the tip and the casing. The endwall pressure measurements and the surface oil flow visualizations were made on a stationary endwall to obtain the flow features and to determine the measurement profiles of interest. A custom-made miniature 3-orthogonal-velocity-component fiber-optic laser-Doppler velocimetry (LDV) system was used to measure all three components of velocity within a 50 mum spherical measurement volume within the gap between the endwall and the blade tip, mainly for the stationary wall with 1.65% and 3.30% tip gaps as well as some initial experiments for the moving wall. Since all of the vorticity in a flow originates from the surfaces under the action of strong pressure gradient, it was very important to measure the nearest-wall flow on the endwall and around the blade tip. The surface skin friction velocity was measured by using viscous sublayer velocity profiles, which verified the presence of an intense lateral shear layer that was observed from surface oil flow visualizations. All second- and third-order turbulence quantities were measured to provide detailed data for any parallel CFD efforts. The most complete data sets were acquired for 1.65% and 3.30% tip gap/chord ratios in a low-speed linear compressor cascade. This study found that tip gap flows are complex pressure-driven, unsteady three-dimensional turbulent flows. The crossflow velocity normal to the blade chord is nearly uniform in the and tip-gap and changes substantially from the pressure to suction side. The crossflow velocity relies on the local tip pressure loading that is different from the mid-span pressure loading because of tip leakage vortex influence. The tip gap flow is highly skewed three-dimensional flow throughout the full gap

  17. Effect of passive flow-control devices on turbulent low-speed base flow

    Science.gov (United States)

    Heidari-Miandoab, Farid

    Some configurations of blunt trailing-edge airfoils are known to have a lower pressure drag compared to sharp trailing-edge airfoils. However, this advantage in addition to the structural advantage of a thick trailing-edge airfoil is offset by its high base drag. At subsonic velocities, this is attributed to the low-pressure base flow dominated by a Karman vortex street. In the limiting case, the steady separated flow over a rearward-facing step is attained if the periodically shed vortices from a blunt trailing-edge are suppressed by the addition of a base spiltter-plate. Experimental studies in the Old Dominion University Low-Speed Closed-Circuit Wind Tunnel were conducted to examine the effect of several passive flow-control devices such as Wheeler doublets and wishbone vortex generators, longitudinal surface grooves, base cavities, and serrations on the characteristics of two- and three-dimensional base flows. Flow over flat-plate airfoil and rearward-facing step models was studied in the turbulent incompressible subsonic flow regime. Models with trailing-edge and step-sweep angles of 0, 30, and 45 degrees with respect to the crossflow direction were considered. Constant-temperature hot-wire anemometry, infrared surface thermography, and pitot-static probes were used to conduct flow measurements. The parameters measured included vortex shedding frequency, convective heat-transfer rates, base pressure, and flow reattachment distance. Surveys of mean velocity profiles in the wake were also conducted. Results have shown that most of the flow control devices tested increased the base pressure of the 2-D and 3-D flat-plate airfoils. Use of longitudinal surface grooves resulted in shorter flow reattachment distances and higher convective heat transfer rates downstream of the 2-D rearward-facing steps.

  18. Low-Speed Fingerprint Image Capture System User`s Guide, June 1, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Whitus, B.R.; Goddard, J.S.; Jatko, W.B.; Manges, W.W.; Treece, D.A.

    1993-06-01

    The Low-Speed Fingerprint Image Capture System (LS-FICS) uses a Sun workstation controlling a Lenzar ElectroOptics Opacity 1000 imaging system to digitize fingerprint card images to support the Federal Bureau of Investigation`s (FBI`s) Automated Fingerprint Identification System (AFIS) program. The system also supports the operations performed by the Oak Ridge National Laboratory- (ORNL-) developed Image Transmission Network (ITN) prototype card scanning system. The input to the system is a single FBI fingerprint card of the agreed-upon standard format and a user-specified identification number. The output is a file formatted to be compatible with the National Institute of Standards and Technology (NIST) draft standard for fingerprint data exchange dated June 10, 1992. These NIST compatible files contain the required print and text images. The LS-FICS is designed to provide the FBI with the capability of scanning fingerprint cards into a digital format. The FBI will replicate the system to generate a data base of test images. The Host Workstation contains the image data paths and the compression algorithm. A local area network interface, disk storage, and tape drive are used for the image storage and retrieval, and the Lenzar Opacity 1000 scanner is used to acquire the image. The scanner is capable of resolving 500 pixels/in. in both x and y directions. The print images are maintained in full 8-bit gray scale and compressed with an FBI-approved wavelet-based compression algorithm. The text fields are downsampled to 250 pixels/in. and 2-bit gray scale. The text images are then compressed using a lossless Huffman coding scheme. The text fields retrieved from the output files are easily interpreted when displayed on the screen. Detailed procedures are provided for system calibration and operation. Software tools are provided to verify proper system operation.

  19. Laboratory Scale Prototype of a Low-Speed Electrodynamic Levitation System Based on a Halbach Magnet Array

    Science.gov (United States)

    Iniguez, J.; Raposo, V.

    2009-01-01

    In this paper we analyse the behaviour of a small-scale model of a magnetic levitation system based on the Inductrack concept. Drag and lift forces acting on our prototype, moving above a continuous copper track, are studied analytically following a simple low-speed approach. The experimental results are in good agreement with the theoretical…

  20. Development of an efficient soymilk cream production method by papain digestion, heat treatment, and low-speed centrifugation.

    Science.gov (United States)

    Abe, Naoki; Wu, Chang-Yu; Kim, Yoon-Kyung; Fujii, Tomoyuki; Abe, Keietsu

    2015-01-01

    We developed the simple method of soymilk cream production from the high-fat soymilk, which was prepared by papain digestion and heat treatment. As a result of the treatment, high-fat soymilk was aggregated and it became possible to separate soymilk cream as the surface fraction by low-speed centrifugation (6000 × g, 10 min).

  1. Improvement of low speed induction generator performances and reducing the power of excitation and voltage control system

    Energy Technology Data Exchange (ETDEWEB)

    Budisan, N. [Politechnica Univ. of Timisoara (Romania); Hentea, T.; Mahil, S. [Purdue Univ. Calumet, Hammond, IN (United States); Madescu, G. [Romanian Academy, Timisoara (Romania)

    1996-12-31

    In this paper we present the results of our investigations concerning the utilization of induction generators at very low speed. It is shown that, by proper design, it is possible to obtain high efficiency and high power factor values. The optimized induction generators require lower reactive power resulting in lower size and price of the excitation control system. 4 refs., 2 figs.

  2. Superresolved phase-shifting Gabor holography by CCD shift

    Science.gov (United States)

    Micó, V.; Granero, L.; Zalevsky, Z.; García, J.

    2009-12-01

    Holography in the Gabor regime is restricted to weak diffraction assumptions. Otherwise, diffraction prevents an accurate recovery of the object's complex wavefront. We have recently proposed a modified Gabor-like setup to extend Gabor's concept to any sample provided that it be non-diffusive. However, the resolution of the final image becomes limited as a consequence of the additional elements considered in the proposed setup. In this paper we present an experimental approach to overcome such a limitation in which the former configuration is used while the CCD camera is shifted to different off-axis positions in order to generate a synthetic aperture. Thus, once the whole image set is recorded and digitally processed for each camera position, we merge the resulting band-pass images into one image by assembling a synthetic aperture. Finally, a superresolved image is recovered by Fourier transformation of the information contained in the generated synthetic aperture. Experimental results validate our concepts for a gain in resolution of close to 2.

  3. The IEEE-1394 Digital Camera Application in the Taiwan Light Source

    CERN Document Server

    Kuo, Changhor; Wang, Min-Huey

    2005-01-01

    The CCD camera with digital interface has been adopted for the diagnostics purpose recently. The long distance transmission with digital interface eliminates image distortion. Without frame grabber in the computer that is also another benefit. These applications include screen monitor and optical transition radiation monitor image for injection study, synchrotron radiation monitor of the booster synchrotron and storage ring. An intensified gated CCD camera is also applied for transient profile study. Wider dynamic range and the flexibility of the newly camera provide various functional enhancements for the diagnostics purpose. The effort and achievement will be summary in this report.

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

    Science.gov (United States)

    Fossum, Eric R.

    1993-01-01

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

  5. Diseño, construcción y uso de una cámara CCD para observaciones astronómicas

    OpenAIRE

    Roca Molina, Felipe

    2014-01-01

    En este proyecto se presenta la construcción de una cámara CCD (dispositivo de carga acoplada) para su uso posterior en aplicaciones astronómicas siguiendo y adaptando las indicaciones del texto The CCD Camera Cookbook (Berry et al., 1994). Se explica el funcionamiento de una cámara CCD a nivel sencillo particularizada para el chip TC211 de la casa Texas Instuments. Se ha diseñado y construido las placas necesarias y se ha realizado un amplio estudio del funcionamiento de la...

  6. Distortion of the pixel grid in HST WFC3/UVIS and ACS/WFC CCD detectors and its astrometric correction

    Science.gov (United States)

    Kozhurina-Platais, Vera; Mackenty, John; Golimovski, David; Sirianni, Marco; Borncamp, David; Anderson, Jay; Grogin, Norman

    2016-07-01

    The geometric distortion of the CCD detectors used in the Hubble Space TelescopeWide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) instruments is characterized by both large and fine-scale distortions. The large-scale distortion, due to the complexity of the HST optical assembly, can be modeled by a high-order polynomial. The majority of fine-distortion is inherent to the CCD detectors themselves, which manifests itself as fine-scale, correlated systematic offsets in the residuals from the best-fit polynomial solution. Such systematic offsets across the CCD chip introduce astrometric errors at the level of about 0.1 pix (up to 1.5 μm within the 15 μm pixels). These fine-scale and low-amplitude distortions apparently arise from the spatial irregularities in the pixel grid. For the WFC3/UVIS CCD chips, there is a clear pattern of periodic skew in the lithographic-mask stencil imprinted onto the detector. Similar irregularities in the pixel grid of ACS/WFC CCD chips are even more pronounced by the narrow (68×2048 pixel) lithographic-mask stencil. To remove these distortions, a 2-D correction in the form of a look-up table has been developed using HST images of very dense stellar fields. The post-correction of fine-scale astrometric errors can be removed down to the level of 0.01 pix (0.15 μm) or better.

  7. Experimental studies on the effect of Reynolds and Weber numbers on the impact forces of low-speed droplets colliding with a solid surface

    Science.gov (United States)

    Zhang, Bin; Li, Jingyin; Guo, Penghua; Lv, Qian

    2017-09-01

    The impact force of low-speed droplets colliding with a solid surface was recorded with an experimental setup involving a highly sensitive piezoelectric force transducer and a high-speed camera recording the droplet shape. Water, ethanol, pure glycerin and aqueous glycerin solutions were used. Experimental results showed that dimensionless force is independent of the Weber number in the experimental range of 68-858 but varies with the Reynolds number. The impact is categorized into three types of processes according to the data on dimensionless peak force against the Reynolds number. The first type is a viscosity-dominated one, in which the Reynolds number ranges between 2.9 and 20. In the second type, transition process, the Reynolds number is in the range of 20-230. In the inertia-dominated type, the Reynolds number is larger than 230. In the viscosity-dominated impact, dimensionless peak force decreases rapidly with increasing Reynolds number, and the effect of viscosity could not be ignored. In the inertia-dominated impact, dimensionless peak force remains constant with varying the Reynolds number, that is, impact force is directly proportional to the product of liquid density, velocity squared and diameter squared but is unaffected by the changes in viscosity and surface tension. Furthermore, the deformation of droplet shape due to oscillation affects the impact force; a small horizontal-to-vertical ratio results in small impact force and vice versa.

  8. Nonlinear Time-Domain Strip Theory Formulation for Low-Speed Manoeuvering and Station-Keeping

    Directory of Open Access Journals (Sweden)

    Thor I. Fossen

    2004-10-01

    Full Text Available This paper presents a computer effective nonlinear time-domain strip theory formulation for dynamic positioning (DP and low-speed manoeuvring. Strip theory or 2D potential theory, where the ship is divided in 20 to 30 cross sections, can be used to compute the potential coefficients (added mass and potential damping and the exciting wave loads (Froude-Krylov and diffraction forces. Commercially available programs are ShipX (VERES by Marintek (Fathi, 2004 and SEAWAY by Amarcon (Journée & Adegeest, 2003, for instance. The proposed method can easily be extended to utilize other strip theory formulations or 3-D potential programs like WAMIT (2004. The frequency dependent potential damping, which in classic theory results in a convolution integral not suited for real-time simulation, is compactly represented by using the state-space formulation of Kristiansen & Egeland (2003. The separation of the vessel model into a low-frequency model (represented by zerofrequency added mass and damping and a wave-frequency model (represented by motion transfer functions or RAOs, which is commonly used for simulation, is hence made superfluous. Transformations of motions and coefficients between different coordinate systems and origins, i.e. data frame, hydrodynamic frame, body frame, inertial frame etc., are put into the rigid framework of Fossen (1994, 2002. The kinematic equations of motion are formulated in a compact nonlinear vector representation and the classical kinematic assumption that the Euler angles are small is removed. This is important for computation of accurate control forces at higher roll and pitch angles. The hydrodynamic forces in the steadily translating hydrodynamic reference frame (equilibrium axes are, however, assumed tobe linear. Recipes for computation of retardation functions are presented and frequency dependent viscous damping is included. Emphasis is placed on numerical computations and representation of the data from VERES and

  9. Large output-power, low-speed permanent magnet synchronous motor designs for ship propulsion drive

    Energy Technology Data Exchange (ETDEWEB)

    Rosu, M.

    2001-07-01

    Over the last decade, serious development has taken place in electric motor technology, and its impact is being felt in the shipbuilding community. This development has brought about a new generation of compact, high efficiency electrical machines. High performance, lightweight permanent magnet motors and generators have been developed for a wide range of applications including vehicle propulsion, power generation, pump and compressor drives. These machines combine the advances in magnetic materials and electronic design to provide shipbuilders new options for weight, energy and cost reduction. Permanent magnet machines were built in many different configurations and power classes, ranging from a few hundred watts to multi-megawatts for ship propulsion. Permanent magnet motors and generators for marine use were constructed and tested, all of these machines providing the same outstanding torque and power density. The basic electromagnetic, thermal and mechanical design approaches were established and tested in small prototype machines, the development of larger machines constituting the engineering later in the design process. The goal of this research work is to find an optimum solution in terms of design and suitability of a low-speed and high-power permanent magnet motor for ship propulsion drive. In this work, the study-case analyses are limited to the electromagnetic part of the motor. Two types of radial flux permanent magnet synchronous motors are designed and optimised to meet the propulsion requirements. The first motor has the permanent magnets mounted on the surface of the rotor while the second motor has the permanent magnets mounted on the rotor surface and covered by laminated pole shoes. In their construction, high-energy NdFeB permanent magnets were chosen. These magnetic materials provide a sufficient airgap magnetic flux density with a low volume of material. Moreover, the NdFeB permanent magnets are endowed with high coercivity. As an immediate

  10. All Sky Camera instrument for night sky monitoring

    CERN Document Server

    Mandat, Dusan; Hrabovsky, Miroslav; Schovanek, Petr; Palatka, Miroslav; Travnicek, Petr; Prouza, Michael; Ebr, Jan

    2014-01-01

    The All Sky Camera (ASC) was developed as an universal device for a monitoring of the night sky quality and night sky background measurement. ASC system consists of an astronomical CCD camera, a fish eye lens, a control computer and associated electronics. The measurement is carried out during astronomical twilight. The analysis results are the cloud fraction (the percentage of the sky covered by clouds), night sky brightness (in mag/arcsec2) and light background in the field of view of the camera. The analysis of the cloud fraction is based on the astrometry (comparison to catalogue positions) of the observed stars.

  11. Robust CCD photoelectric autocollimator for outdoor use

    Institute of Scientific and Technical Information of China (English)

    Min Gao; Zuoren Dong; Zhenglan Bian; Qing Ye; Zujie Fang; Ronghui Qu

    2011-01-01

    A robust charge-coupled device (CCD) photoelectric autocollimator for outdoor use is designed and demonstrated. The influence of outdoor conditions on the signal-to-noise ratio (SNR) and imaging quality of the measuring system is experimentally analyzed. The pulse width modulation technology is applied to the automatic feedback control of the actively regulated illuminating light source of the measuring system to maximize SNR while avoiding image saturation. A Fourier phase shift method for subpixel estimation is adopted to achieve high-accuracy measurement in the presence of noises. Experimental results indicate that the technologies proposed here largely improve the measuring stability, dynamic range, and accuracy of the CCD photoelectric autocollimator used outdoors.%@@ A robust charge-coupled device(CCD)photoelectric autocollimator for outdoor use is designed and demonstrated.The influence of outdoor conditions on the signal-to-noise ratio(SNR)and imaging quality of the measuring system is experimentally analyzed.The pulse width modulation technology is applied to the automatic feedback control of the actively regulated illuminating light source of the measuring system to maximize SNR while avoiding image saturation.A Fourier phase shift method for subpixel estimation is adopted to achieve high-accuracy measurement in the presence of noises.Experimental results indicate that the technologies proposed here largely improve the measuring stability,dynamic range,and accuracy of the CCD photoelectric autocollimator used outdoors.

  12. Vision Sensors and Cameras

    Science.gov (United States)

    Hoefflinger, Bernd

    Silicon charge-coupled-device (CCD) imagers have been and are a specialty market ruled by a few companies for decades. Based on CMOS technologies, active-pixel sensors (APS) began to appear in 1990 at the 1 μm technology node. These pixels allow random access, global shutters, and they are compatible with focal-plane imaging systems combining sensing and first-level image processing. The progress towards smaller features and towards ultra-low leakage currents has provided reduced dark currents and μm-size pixels. All chips offer Mega-pixel resolution, and many have very high sensitivities equivalent to ASA 12.800. As a result, HDTV video cameras will become a commodity. Because charge-integration sensors suffer from a limited dynamic range, significant processing effort is spent on multiple exposure and piece-wise analog-digital conversion to reach ranges >10,000:1. The fundamental alternative is log-converting pixels with an eye-like response. This offers a range of almost a million to 1, constant contrast sensitivity and constant colors, important features in professional, technical and medical applications. 3D retino-morphic stacking of sensing and processing on top of each other is being revisited with sub-100 nm CMOS circuits and with TSV technology. With sensor outputs directly on top of neurons, neural focal-plane processing will regain momentum, and new levels of intelligent vision will be achieved. The industry push towards thinned wafers and TSV enables backside-illuminated and other pixels with a 100% fill-factor. 3D vision, which relies on stereo or on time-of-flight, high-speed circuitry, will also benefit from scaled-down CMOS technologies both because of their size as well as their higher speed.

  13. Overview of Low-Speed Aerodynamic Tests on a 5.75% Scale Blended-Wing-Body Twin Jet Configuration

    Science.gov (United States)

    Vicroy, Dan D.; Dickey, Eric; Princen, Norman; Beyar, Michael D.

    2016-01-01

    The NASA Environmentally Responsible Aviation (ERA) Project sponsored a series of computational and experimental investigations of the propulsion and airframe integration issues associated with Hybrid-Wing-Body (HWB) or Blended-Wing-Body (BWB) configurations. NASA collaborated with Boeing Research and Technology (BR&T) to conduct this research on a new twin-engine Boeing BWB transport configuration. The experimental investigations involved a series of wind tunnel tests with a 5.75-percent scale model conducted in two low-speed wind tunnels. This testing focused on the basic aerodynamics of the configuration and selection of the leading edge Krueger slat position for takeoff and landing. This paper reviews the results and analysis of these low-speed wind tunnel tests.

  14. Statistical predictions for the dynamics of a low-speed system: Newtonian versus special-relativistic mechanics.

    Directory of Open Access Journals (Sweden)

    Shiuan-Ni Liang

    Full Text Available The newtonian and special-relativistic statistical predictions for the mean, standard deviation and probability density function of the position and momentum are compared for the periodically-delta-kicked particle at low speed. Contrary to expectation, we find that the statistical predictions, which are calculated from the same parameters and initial gaussian ensemble of trajectories, do not always agree if the initial ensemble is sufficiently well-localized in phase space. Moreover, the breakdown of agreement is very fast if the trajectories in the ensemble are chaotic, but very slow if the trajectories in the ensemble are non-chaotic. The breakdown of agreement implies that special-relativistic mechanics must be used, instead of the standard practice of using newtonian mechanics, to correctly calculate the statistical predictions for the dynamics of a low-speed system.

  15. Statistical predictions for the dynamics of a low-speed system: Newtonian versus special-relativistic mechanics.

    Science.gov (United States)

    Liang, Shiuan-Ni; Lan, Boon Leong

    2012-01-01

    The newtonian and special-relativistic statistical predictions for the mean, standard deviation and probability density function of the position and momentum are compared for the periodically-delta-kicked particle at low speed. Contrary to expectation, we find that the statistical predictions, which are calculated from the same parameters and initial gaussian ensemble of trajectories, do not always agree if the initial ensemble is sufficiently well-localized in phase space. Moreover, the breakdown of agreement is very fast if the trajectories in the ensemble are chaotic, but very slow if the trajectories in the ensemble are non-chaotic. The breakdown of agreement implies that special-relativistic mechanics must be used, instead of the standard practice of using newtonian mechanics, to correctly calculate the statistical predictions for the dynamics of a low-speed system.

  16. Low-Speed Control of Heavy-Load Transfer Robot with Long Telescopic Boom Based on Stribeck Friction Model

    Directory of Open Access Journals (Sweden)

    Bo You

    2012-01-01

    Full Text Available The severe low-speed creep phenomenon occurs in the telescopic boom system of a heavy-load transfer robot with a long telescopic boom as a result of nonlinear friction. In order to improve control precision and operation performance at low speeds, we built a three-loop control nonlinear model of an AC servo motor with Stribeck friction disturbance. Traditional proportional-integral-derivative controller (PID and fuzzy PID controls were, respectively, adopted in the position loop, and the control performance was simulated. The results showed that a system with fuzzy PID control eliminates “flat top” position tracking and “dead zone” speed tracking, which are generated by traditional PID, and thereby decreases the effect of friction on the performance of the servo system. This elimination also improved the tracking accuracy and robustness of the system.

  17. Concurrent Flame Growth, Spread and Extinction over Composite Fabric Samples in Low Speed Purely Forced Flow in Microgravity

    Science.gov (United States)

    Zhao, Xiaoyang; T'ien, James S.; Ferkul, Paul V.; Olson, Sandra L.

    2015-01-01

    As a part of the NASA BASS and BASS-II experimental projects aboard the International Space Station, flame growth, spread and extinction over a composite cotton-fiberglass fabric blend (referred to as the SIBAL fabric) were studied in low-speed concurrent forced flows. The tests were conducted in a small flow duct within the Microgravity Science Glovebox. The fuel samples measured 1.2 and 2.2 cm wide and 10 cm long. Ambient oxygen was varied from 21% down to 16% and flow speed from 40 cm/s down to 1 cm/s. A small flame resulted at low flow, enabling us to observe the entire history of flame development including ignition, flame growth, steady spread (in some cases) and decay at the end of the sample. In addition, by decreasing flow velocity during some of the tests, low-speed flame quenching extinction limits were found as a function of oxygen percentage. The quenching speeds were found to be between 1 and 5 cm/s with higher speed in lower oxygen atmosphere. The shape of the quenching boundary supports the prediction by earlier theoretical models. These long duration microgravity experiments provide a rare opportunity for solid fuel combustion since microgravity time in ground-based facilities is generally not sufficient. This is the first time that a low-speed quenching boundary in concurrent spread is determined in a clean and unambiguous manner.

  18. STEADY STATE PERFORMANCES ANALYSIS OF MODERN MARINE TWO-STROKE LOW SPEED DIESEL ENGINE USING MLP NEURAL NETWORK MODEL

    Directory of Open Access Journals (Sweden)

    Ozren Bukovac

    2016-01-01

    Full Text Available Compared to the other marine engines for ship propulsion, turbocharged two-stroke low speed diesel engines have advantages due to their high efficiency and reliability. Modern low speed ”intelligent” marine diesel engines have a flexibility in its operation due to the variable fuel injection strategy and management of the exhaust valve drive. This paper carried out verified zerodimensional numerical simulations which have been used for MLP (Multilayer Perceptron neural network predictions of marine two-stroke low speed diesel engine steady state performances. The developed MLP neural network was used for marine engine optimized operation control. The paper presents an example of achieving lowest specific fuel consumption and for minimization of the cylinder process highest temperature for reducing NOx emission. Also, the developed neural network was used to achieve optimal exhaust gases heat flow for utilization. The obtained data maps give insight into the optimal working areas of simulated marine diesel engine, depending on the selected start of the fuel injection (SOI and the time of the exhaust valve opening (EVO.

  19. Fully depleted back-illuminated p-channel CCD development

    Energy Technology Data Exchange (ETDEWEB)

    Bebek, Chris J.; Bercovitz, John H.; Groom, Donald E.; Holland, Stephen E.; Kadel, Richard W.; Karcher, Armin; Kolbe, William F.; Oluseyi, Hakeem M.; Palaio, Nicholas P.; Prasad, Val; Turko, Bojan T.; Wang, Guobin

    2003-07-08

    An overview of CCD development efforts at Lawrence Berkeley National Laboratory is presented. Operation of fully-depleted, back-illuminated CCD's fabricated on high resistivity silicon is described, along with results on the use of such CCD's at ground-based observatories. Radiation damage and point-spread function measurements are described, as well as discussion of CCD fabrication technologies.

  20. Puesta en marcha de un microdensitómetro automático basado en CCD

    Science.gov (United States)

    Calderón, J. H.; Bustos Fierro, I. H.

    We present the commisioning of a CCD-based microdensitometer intended to perform astrometric measurements of photographic plates. The work done consisted in the installation of a CCD camera, the modification of the motion system, the construction of a new illumination device, the adaptation of the electronics, and the development of software. The instrument is intended to be used for the astrometric measurement mainly of plates of the Astrographic Catalog and Carte du Ciel collections from Córdoba Observatory. In this phase of the project we counted with the collaboration of the Instituto Provincial de Enseñanza Media No 59, 25 de Mayo, Cruz Alta (Province of Córdoba). The origin and importance of such collaboration is commented.

  1. The Zwicky Transient Facility Camera

    Science.gov (United States)

    Dekany, Richard; Smith, Roger M.; Belicki, Justin; Delacroix, Alexandre; Duggan, Gina; Feeney, Michael; Hale, David; Kaye, Stephen; Milburn, Jennifer; Murphy, Patrick; Porter, Michael; Reiley, Daniel J.; Riddle, Reed L.; Rodriguez, Hector; Bellm, Eric C.

    2016-08-01

    The Zwicky Transient Facility Camera (ZTFC) is a key element of the ZTF Observing System, the integrated system of optoelectromechanical instrumentation tasked to acquire the wide-field, high-cadence time-domain astronomical data at the heart of the Zwicky Transient Facility. The ZTFC consists of a compact cryostat with large vacuum window protecting a mosaic of 16 large, wafer-scale science CCDs and 4 smaller guide/focus CCDs, a sophisticated vacuum interface board which carries data as electrical signals out of the cryostat, an electromechanical window frame for securing externally inserted optical filter selections, and associated cryo-thermal/vacuum system support elements. The ZTFC provides an instantaneous 47 deg2 field of view, limited by primary mirror vignetting in its Schmidt telescope prime focus configuration. We report here on the design and performance of the ZTF CCD camera cryostat and report results from extensive Joule-Thompson cryocooler tests that may be of broad interest to the instrumentation community.

  2. M2-F1 in flight during low-speed car tow

    Science.gov (United States)

    1963-01-01

    The M2-F1 shown in flight during a low-speed car tow runs across the lakebed. Such tests allowed about two minutes to test the vehicle's handling in flight. NASA Flight Research Center (later redesignated the Dryden Flight Research Center) personnel conducted as many as 8 to 14 ground-tow flights in a single day either to test the vehicle in preparation for air tows or to train pilots to fly the vehicle before they undertook air tows. The wingless, lifting body aircraft design was initially concieved as a means of landing an aircraft horizontally after atmospheric reentry. The absence of wings would make the extreme heat of re-entry less damaging to the vehicle. In 1962, Dryden management approved a program to build a lightweight, unpowered lifting body as a prototype to flight test the wingless concept. It would look like a 'flying bathtub,' and was designated the M2-F1, the 'M' referring to 'manned' and 'F' referring to 'flight' version. It featured a plywood shell placed over a tubular steel frame crafted at Dryden. Construction was completed in 1963. The first flight tests of the M2-F1 were over Rogers Dry Lake at the end of a tow rope attached to a hopped-up Pontiac convertible driven at speeds up to about 120 mph. This vehicle needed to be able to tow the M2-F1 on the Rogers Dry Lakebed adjacent to NASA's Flight Research Center (FRC) at a minimum speed of 100 miles per hour. To do that, it had to handle the 400-pound pull of the M2-F1. Walter 'Whitey' Whiteside, who was a retired Air Force maintenance officer working in the FRC's Flight Operations Division, was a dirt-bike rider and hot-rodder. Together with Boyden 'Bud' Bearce in the Procurement and Supply Branch of the FRC, Whitey acquired a Pontiac Catalina convertible with the largest engine available. He took the car to Bill Straup's renowned hot-rod shop near Long Beach for modification. With a special gearbox and racing slicks, the Pontiac could tow the 1,000-pound M2-F1 110 miles per hour in 30

  3. Camera for QUasars in EArly uNiverse (CQUEAN)

    CERN Document Server

    Park, Won-Kee; Im, Myungshin; Choi, Changsu; Jeon, Yiseul; Chang, Seunghyuk; Jeong, Hyeonju; Lim, Juhee; Kim, Eunbin

    2012-01-01

    We describe the overall characteristics and the performance of an optical CCD camera system, Camera for QUasars in EArly uNiverse (CQUEAN), which is being used at the 2.1 m Otto Struve Telescope of the McDonald Observatory since 2010 August. CQUEAN was developed for follow-up imaging observations of red sources such as high redshift quasar candidates (z >= 5), Gamma Ray Bursts, brown dwarfs, and young stellar objects. For efficient observations of the red objects, CQUEAN has a science camera with a deep depletion CCD chip which boasts a higher quantum efficiency at 0.7 - 1.1 um than conventional CCD chips. The camera was developed in a short time scale (~ one year), and has been working reliably. By employing an auto-guiding system and a focal reducer to enhance the field of view on the classical Cassegrain focus, we achieve a stable guiding in 20 minute exposures, an imaging quality with FWHM >= 0.6" over the whole field (4.8' * 4.8'), and a limiting magnitude of z = 23.4 AB mag at 5-sigma with one hour tota...

  4. Flat-Field Calibration of CCD Detector for Long TraceProfilers

    Energy Technology Data Exchange (ETDEWEB)

    Kirschman, Jonathan L.; Domning, Edward E.; Franck, Keith D.; Irick, Steve C.; MacDowell, Alastair A.; McKinney, Wayne R.; Morrison,Gregory Y.; Smith, Brian V.; Warwick, Tony; Yashchuk, Valeriy V.

    2007-07-31

    The next generation of synchrotrons and free electron lasersrequires x-ray optical systems with extremely high-performance,generally, of diffraction limited quality. Fabrication and use of suchoptics requires highly accurate metrology. In the present paper, wediscuss a way to improve the performance of the Long Trace Profiler(LTP), a slope measuring instrument widely used at synchrotron facilitiesto characterize x-ray optics at high-spatial-wavelengths fromapproximately 2 mm to 1 m. One of the major sources of LTP systematicerror is the detector. For optimal functionality, the detector has topossess the smallest possible pixel size/spacing, a fast method ofshuttering, and minimal non-uniformity of pixel-to-pixel photoresponse.While the first two requirements are determined by choice of detector,the non-uniformity of photoresponse of typical detectors such as CCDcameras is around 2-3 percent. We describe a flat-field calibration setupspecially developed for calibration of CCD camera photo-response and darkcurrent with an accuracy of better than 0.5 percent. Such accuracy isadequate for use of a camera as a detector for an LTP with performance of~;0.1 microradian (rms). We also present the design details of thecalibration system and results of calibration of a DALSA CCD camera usedfor upgrading our LTP-II instrument at the ALS Optical MetrologyLaboratory.

  5. Improving the resolution in phase-shifting Gabor holography by CCD shift

    Science.gov (United States)

    Granero, L.; Micó, V.; Zalevsky, Z.; García, J.; Javidi, B.

    2015-05-01

    Holography dates back to the year when Dennis Gabor reported on a method to avoid spherical aberration and to improve image quality in electron microscopy. Gabor's two-step holographic method was pioneer but suffered from three major drawbacks: the reconstructed image is affected by coherent noise, the twin image problem of holography that also affects the final image quality, and a restricted sample range (weak diffraction assumption) for preserving the holographic behavior of the method. Nowadays, most of those drawbacks have been overcome and new capabilities have been added due to the replacement of the classical recording media (photographic plate) by digital sensors (CCD and CMOS cameras). But in the Gabor' regime, holography is restricted to weak diffraction assumptions because otherwise, diffraction prevents an accurate recovery of the object's complex wavefront. In this contribution, we present an experimental approach to overcome such limitation and improve final image resolution. We use the phase-shifting Gabor configuration while the CCD camera is shifted to different off-axis positions in order to capture a bigger portion of the diffracted wavefront. Thus, once the whole image set is recorded and digitally processed for each camera's position, we merge the resulting band-pass images into one image by assembling a synthetic aperture. Finally, a superresolved image is recovered by Fourier transformation of the information contained in the generated synthetic aperture. Experimental results are provided using a USAF resolution test target and validating our concepts for a gain in resolution of close to 2.

  6. Radiation events in astronomical CCD images

    OpenAIRE

    Smith, A. R.; McDonald, R. J.; Hurley, D. L.; Holland, S. E.; Groom, D. E.; Brown, W E; Gilmore, D. K.; Stover, R.J.; Wei, M.

    2001-01-01

    The remarkable sensitivity of depleted silicon to ionizing radiation is a nuisance to astronomers. "Cosmic rays" degrade images because of struck pixels, leading to modified observing strategies and the development of algorithms to remove the unwanted artifacts. In the new-generation CCD's with thick sensitive regions, cosmic-ray muons make recognizable straight tracks and there is enhanced sensitivity to ambient gamma radiation via Compton-scattered electrons ("worms"). Beta emitters i...

  7. CCD Photometry of Asteroid (147) Protogeneia

    Institute of Scientific and Technical Information of China (English)

    Xi-Liang Zhang; Xiao-Bin Wang; Li-Yun Zhang

    2006-01-01

    We measured the light-curve of the asteroid (147) Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of (147) at this apparition are 7.852 hours and 0.25 mag, respectively. The value of a/b for (147), from a preliminary estimation, is not less than 1.26:1.

  8. PSF and MTF Measurement Methods for Thick CCD Sensor Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, P.Z.; Kotov, I.; Frank, J.; O' Connor, P.; Radeka, V.; Lawrence, D.M.

    2010-06-30

    Knowledge of the point spread function (PSF) of the sensors to be used in the Large Synoptic Survey Telescope (LSST) camera is essential for optimal extraction of subtle galaxy shape distortions caused by gravitational weak lensing. We have developed a number of techniques for measuring the PSF of candidate CCD sensors to be used in the LSST camera, each with its own strengths and weaknesses. The two main optical PSF measurement techniques that we use are the direct Virtual Knife Edge (VKE) scan as developed by Karcher, et al. and the indirect interference fringe method after Andersen and Sorensen that measures the modulation transfer function (MTF) directly. The PSF is derived from the MTF by Fourier transform. Other non-optical PSF measurement techniques that we employ include {sup 55}Fe x-ray cluster image size measurements and statistical distribution analysis, and cosmic ray muon track size measurements, but are not addressed here. The VKE technique utilizes a diffraction-limited spot produced by a Point-Projection Microscope (PPM) that is scanned across the sensor with sub-pixel resolution. This technique closely simulates the actual operating condition of the sensor in the telescope with the source spot size having an f/number close to the actual telescope design value. The interference fringe method uses a simple equal-optical-path Michelson-type interferometer with a single-mode fiber source that produces interference fringes with 100% contrast over a wide spatial frequency range sufficient to measure the MTF of the sensor directly. The merits of each measurement technique and results from the various measurement techniques on prototype LSST sensors are presented and compared.

  9. Behavior of skin color under varying illumination seen by different cameras at different color spaces

    Science.gov (United States)

    Martinkauppi, J. Birgitta; Soriano, Maricor N.; Laaksonen, Mika V.

    2001-04-01

    The appearance of skin colors in the images depends among other things, on the camera, the calibration of the camera, and the illumination under which the image was taken. In this study, we investigate how the skin colors appear in the chromaticity coordinates of different color spaces like HSV/HSL, normalized rgb, YES and TSL. For this purpose, we have taken images of faces under 16 different illumination/camera calibration conditions using simulated illuminants (Horizon, A, fluorescent TL84 and daylight) with different RGB cameras (1CCD web cameras and a 3CCD camera). In the making of this series of 16 images, first the selected camera was calibrated to one of the four light sources and an image was taken. After that the light source was changed to the other light sources and at each time the person was imaged. The process was repeated to the other two light sources. The same procedure was done for all four light sources and for each camera. The skin regions were extracted from these images and this skin data was then converted to different color spaces. We inspected how the chromaticities of different skin color groups in these color spaces overlap in images taken in all 16 different cases and only in those cases in which the selected camera was calibrated to the current illuminant. These investigations were also made between different cameras. In addition to this, we examined the overlapping of all skin chromaticities from the different skin color groups between cameras.

  10. A comparison of CsI:Tl and GOS in a scintillator-CCD detector for nuclear medicine imaging

    Science.gov (United States)

    Bugby, S. L.; Jambi, L. K.; Lees, J. E.

    2016-09-01

    A number of portable gamma cameras for medical imaging use scintillator-CCD based detectors. This paper compares the performance of a scintillator-CCD based portable gamma camera with either a columnar CsI:Tl or a pixelated GOS scintillator installed. The CsI:Tl scintillator has a sensitivity of 40% at 140.5 keV compared to 54% with the GOS scintillator. The intrinsic spatial resolution of the pixelated GOS detector was 1.09 mm, over 4 times poorer than for CsI:Tl. Count rate capability was also found to be significantly lower when the GOS scintillator was used. The uniformity was comparable for both scintillators.

  11. High speed single charge coupled device Cranz-Schardin camera

    Science.gov (United States)

    Deblock, Y.; Ducloux, O.; Derbesse, L.; Merlen, A.; Pernod, P.

    2007-03-01

    This article describes an ultrahigh speed visualization system based on a miniaturization of the Cranz-Schardin principle. It uses a set of high power light emitting diodes (LEDs) (Golden Dragon) as the light source and a highly sensitive charge coupled device (CCD) camera for reception. Each LED is fired in sequence and images the refraction index variation between two relay lenses, on a partial region of a CCD image sensor. The originality of this system consists in achieving several images on a single CCD during a frame time. The number of images is 4. The time interval between successive firings determines the speed of the imaging system. This time lies from 100nsto10μs. The light pulse duration lies from 100nsto10μs. The principle and the optical and electronic parts of such a system are described. As an example, some images of acoustic waves propagating in water are presented.

  12. Upgrade of ESO's FIERA CCD Controller and PULPO Subsystem

    Science.gov (United States)

    Reyes-Moreno, J.; Geimer, C.; Balestra, A.; Haddad, N.

    An overview of FIERA is presented with emphasis on its recent upgrade to PCI. The PCI board hosts two DSPs, one for real time control of the camera and another for on-the-fly processing of the incoming video data. In addition, the board is able to make DMA transfers, to synchronize to other boards alike, to be synchronized by a TIM bus and to control PULPO via RS232. The design is based on the IOP480 chip from PLX, for which we have developed a device driver for both Solaris and Linux. One computer is able to host more than one board and therefore can control an array of FIERA detector electronics. PULPO is a multifunctional subsystem widely used at ESO for the housekeeping of CCD cryostat heads and for shutter control. The upgrade of PULPO is based on an embedded PC running Linux. The upgraded PULPO is able to handle 29 temperature sensors, control 8 heaters and one shutter, read out one vacuum sensor and log any combination of parameters.

  13. Asteroid detection using a single multi-wavelength CCD scan

    Science.gov (United States)

    Melton, Jonathan

    2016-09-01

    Asteroid detection is a topic of great interest due to the possibility of diverting possibly dangerous asteroids or mining potentially lucrative ones. Currently, asteroid detection is generally performed by taking multiple images of the same patch of sky separated by 10-15 minutes, then subtracting the images to find movement. However, this is time consuming because of the need to revisit the same area multiple times per night. This paper describes an algorithm that can detect asteroids using a single CCD camera scan, thus cutting down on the time and cost of an asteroid survey. The algorithm is based on the fact that some telescopes scan the sky at multiple wavelengths with a small time separation between the wavelength components. As a result, an object moving with sufficient speed will appear in different places in different wavelength components of the same image. Using image processing techniques we detect the centroids of points of light in the first component and compare these positions to the centroids in the other components using a nearest neighbor algorithm. The algorithm was used on a test set of 49 images obtained from the Sloan telescope in New Mexico and found 100% of known asteroids with only 3 false positives. This algorithm has the advantage of decreasing the amount of time required to perform an asteroid scan, thus allowing more sky to be scanned in the same amount of time or freeing a telescope for other pursuits.

  14. Remote operation over low speed, high latency links; Operacao remota confiavel usando circuitos de baixa velocidade e alta latencia

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Marcelo D.; Nunes, Ildemar P. [Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil)

    2004-07-01

    Remote Control and monitoring of a compressor station with more than 3000 tags can be a hard task to accomplish over a low speed satellite link. This paper presents Datasync, an application specially developed to provide acceptable performance levels over a VSAT link. One of its main features is to enable the establishment of communication dead bands. The dead bands can be altered while the application is running (no restart is needed), so that the operator is able to increase a specific tag's dead band immediately after detecting that it is reporting too many exceptions, which would cause an increase on the traffic and response times. (author)

  15. Impact of PLL Parameters Variation on the Pulsating Voltage Injection Technique Based PMSM Position Estimation at Low Speeds

    Directory of Open Access Journals (Sweden)

    Olfa Bel Hadj Brahim Kechiche

    2014-06-01

    Full Text Available This study highlights the impact of an universal Phase Locked Loop (PLL parameters variation on PMSM position estimation at low speeds. Indeed, the PLL parameters variation impact on the PMSM rotor position estimation performance and robustness cannot be neglected anymore. For this purpose, the study presents the theory and simulation results of a demodulation scheme applied to Sensorless PMSM control based on the Pulsating Voltage Injection (PVI technique. Comprehensive simulations, carried out under MATLAB/SIMULINK®, are discussed according to the variation of the PLL proportional and integral parameters.

  16. Steady and Unsteady Casingwall Flow Phenomena in a Single-Stage Low-Speed Compressor at Part-Load Conditions

    Directory of Open Access Journals (Sweden)

    H. Saathoff

    2003-01-01

    Full Text Available This article describes an investigation of the casingwall flow phenomena in a single-stage, axial-flow, low-speed compressor at part-load conditions, utilizing an oil-flow technique to visualize the boundary layer development and highfrequency sensors to measure ensemble-averaged velocity and flow-angle distributions as well as unsteady total pressure distributions. Representative results are shown and discussed. The results enable different sources of endwall blockage to be identified and changes with flow rate to be determined.

  17. Error Reduction in Portable, Low-Speed Weigh-In-Motion (Sub-0.1 Percent Error)

    Energy Technology Data Exchange (ETDEWEB)

    Abercrombie, Robert K [ORNL; Hively, Lee M [ORNL; Scudiere, Matthew B [ORNL; Sheldon, Frederick T [ORNL

    2008-01-01

    We present breakthrough findings based on significant modifications to the Weigh-in-Motion (WIM) Gen II approach, so-called the modified Gen II. The revisions enable slow speed weight measurements at least as precise as in ground static scales, which are certified to 0.1% error. Concomitant software and hardware revisions reflect a philosophical and practical change that enables an order of magnitude improvement in low-speed weighing precision. This error reduction breakthrough is presented within the context of the complete host of commercial and governmental application rationale including the flexibility to extend information and communication technology for future needs.

  18. VIRUS-P: camera design and performance

    Science.gov (United States)

    Tufts, Joseph R.; MacQueen, Phillip J.; Smith, Michael P.; Segura, Pedro R.; Hill, Gary J.; Edmonston, Robert D.

    2008-07-01

    We present the design and performance of the prototype Visible Integral-field Replicable Unit Spectrograph (VIRUS-P) camera. Commissioned in 2007, VIRUS-P is the prototype for 150+ identical fiber-fed integral field spectrographs for the Hobby-Eberly Telescope Dark Energy Experiment. With minimal complexity, the gimbal mounted, double-Schmidt design achieves high on-sky throughput, image quality, contrast, and stability with novel optics, coatings, baffling, and minimization of obscuration. The system corrector working for both the collimator and f / 1.33 vacuum Schmidt camera serves as the cryostat window while a 49 mm square aspheric field flattener sets the central obscuration. The mount, electronics, and cooling of the 2k × 2k, Fairchild Imaging CCD3041-BI fit in the field-flattener footprint. Ultra-black knife edge baffles at the corrector, spider, and adjustable mirror, and a detector mask, match the optical footprints at each location and help maximize the 94% contrast between 245 spectra. An optimally stiff and light symmetric four vane stainless steel spider supports the CCD which is thermally isolated with an equally stiff Ultem-1000 structure. The detector/field flattener spacing is maintained to 1 μm for all camera orientations and repeatably reassembled to 12 μm. Invar rods in tension hold the camera focus to +/-4 μm over a -5-25 °C temperature range. Delivering a read noise of 4.2 e- RMS, sCTE of 1-10-5 , and pCTE of 1-10-6 at 100 kpix/s, the McDonald V2 controller also helps to achieve a 38 hr hold time with 3 L of LN2 while maintaining the detector temperature setpoint to 150 μK (5σ RMS).

  19. ACS after SM4: On-orbit Verification of the HST Advanced Camera for Surveys Repair

    Science.gov (United States)

    Golimowski, David A.; Cheng, E. S.; Loose, M.; Sirianni, M.; Lupie, O. L.; Smith, L. J.; Arslanian, S.; Boyce, K. R.; Chapman, G.; Chiaberge, M.; Desjardins, T.; Dye, D.; Ellis, T.; Grogin, N. A.; Lim, P.; Lucas, R. A.; Maybhate, A.; Mil, K. J.; Mutchler, M.; Ricardo, R.; Scott, B.; Serrano, B.; Suchkov, A.; Waczynski, A.; Welty, A. D.; Wheeler, T.; Wilson, E.

    2010-01-01

    The newly replaced CCD electronics box (CEB-R) of the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) features a programmable SIDECAR ASIC manufactured by Teledyne. The CEB-R not only restores the functionality of the ACS Wide Field Camera (WFC), but it allows optimization of the WFC's imaging performance via on-orbit adjustment of CCD bias and clock voltages and serial-data transmission timing. We describe the strategy, preparation, execution, and results of the ACS Optimization Campaign, an unprecedented on-orbit extension of ground-based integration and testing that was conducted during the HST Servicing Mission Observatory Verification period.

  20. Acute duodenal Crohn's disease successfully managed with low-speed elemental diet infusion via nasogastric tube: A case report

    Institute of Scientific and Technical Information of China (English)

    Takayuki Yamamoto; Maki Nakahigashi; Satoru Umegae; Tatsushi Kitagawa; Koichi Matsumoto

    2006-01-01

    Duodenal Crohn's disease is rare, and patients without obstruction are treated medically. We herein report one case whose duodenal Crohn's disease was successfully managed with low-speed elemental diet infusion through a nasogastric tube. A 28-year-old female developed acute duodenal Crohn's disease. Upper GI radiologic and endoscopic examinations showed a stricture in the duodenal bulb. Using the duodenal biopsy specimens,mucosal cytokine levels were measured; interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α levels were remarkably elevated. For initial 2 wk, powdered mesalazine was orally given but it was not effective. For the next 2 wk, she was treated with low-speed elemental diet therapy using a commercially available ElentalTM,which was infused continuously through a nasogastric tube using an infusion pump. The tip of the nasogastric tube was placed at an immediate oral side of the pylorus.The infusion speed was 10 mL/h (usual speed, 100 mL/h).After the 2-wk treatment, her symptoms were very much improved, and endoscopically, the duodenal stricture and inflammation improved. The duodenal mucosal cytokine levels remarkably decreased compared with those before the treatment. Although our experience was limited, lowspeed elemental diet infusion through a nasogastric tube may be a useful treatment for acute duodenal Crohn's disease.

  1. NASA low-speed centrifugal compressor for 3-D viscous code assessment and fundamental flow physics research

    Science.gov (United States)

    Hathaway, M. D.; Wood, J. R.; Wasserbauer, C. A.

    1991-01-01

    A low speed centrifugal compressor facility recently built by the NASA Lewis Research Center is described. The purpose of this facility is to obtain detailed flow field measurements for computational fluid dynamic code assessment and flow physics modeling in support of Army and NASA efforts to advance small gas turbine engine technology. The facility is heavily instrumented with pressure and temperature probes, both in the stationary and rotating frames of reference, and has provisions for flow visualization and laser velocimetry. The facility will accommodate rotational speeds to 2400 rpm and is rated at pressures to 1.25 atm. The initial compressor stage being tested is geometrically and dynamically representative of modern high-performance centrifugal compressor stages with the exception of Mach number levels. Preliminary experimental investigations of inlet and exit flow uniformly and measurement repeatability are presented. These results demonstrate the high quality of the data which may be expected from this facility. The significance of synergism between computational fluid dynamic analysis and experimentation throughout the development of the low speed centrifugal compressor facility is demonstrated.

  2. Low-speed Impact Simulations into Regolith in Support of Asteroid Sampling Mechanism Design I.: Comparison with 1-g Experiments

    CERN Document Server

    Schwartz, Stephen R; Richardson, Derek C; Yano, Hajime

    2014-01-01

    This study is carried out in the framework of sample-return missions to asteroids that use a low-speed projectile as the primary component of its sampling mechanism (e.g., JAXA's Hayabusa and Hayabusa2 missions). We perform numerical simulations of such impacts into granular materials using different projectile shapes under Earth's gravity. We then compare the amounts of ejected mass obtained in our simulations against what was found in experiments that used similar setups, which allows us to validate our numerical approach. For the targets, we consider 2 different monodisperse grain-diameter sizes: 5 mm and 3 mm. The impact speed of the projectile is 11 m s$^{-1}$ directed downward, perpendicular to the surface of the targets. Using an implementation of the soft-sphere discrete element method (SSDEM) in the $N$-Body gravity tree code PKDGRAV, previously validated in the context of low-speed impacts into sintered glass bead agglomerates, we find a noticeable dependence of the amount of ejected mass on the pro...

  3. Coronal Heating and Acceleration of the High/Low-Speed Solar Wind by Fast/Slow MHD Shock Trains

    CERN Document Server

    Suzuki, T K

    2004-01-01

    We investigate coronal heating and acceleration of the high- and low-speed solar wind in the open field region by dissipation of fast and slow magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized \\Alfven (fast MHD) waves and acoustic (slow MHD) waves travelling upwardly along with a magnetic field line eventually form fast switch-on shock trains and hydrodynamical shock trains (N-waves) respectively to heat and accelerate the plasma. We determine one dimensional structure of the corona from the bottom of the transition region (TR) to 1AU under the steady-state condition by solving evolutionary equations for the shock amplitudes simultaneously with the momentum and proton/electron energy equations. Our model reproduces the overall trend of the high-speed wind from the polar holes and the low-speed wind from the mid- to low-latitude streamer except the observed hot corona in the streamer. The heating from the slow waves is effective in the low corona to increase the density there, and plays ...

  4. Ghost Images in Schmidt CCD Photometry

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The wide field of the Schmidt telescope implies a greater chance of the field containing bright objects, and the presence of a corrector lens produces a certain type of ghost images. We summarize and confirm the features of such ghost images in Schmidt CCD photometry. The ghost images could be star-like under special observational conditions. The zenith distance of the telescope, among other factors, is found to correlate with different patterns of the ghost images. Some relevant issues are discussed and possible applications of our results are suggested.

  5. New CCD Photometry Study of RV UMa

    CERN Document Server

    Tasselli, D

    2015-01-01

    All available CCD observation of RV UMa have been analyzed to obtain an accurate mathematical description of the ligh variation. We discuss in this paper a new study of variable star RV UMa, a short period RRab star, in orther to determine through the light curve and the physical parameters, the presence of "Blazhko effect". The Star were observed for a total of 839 sessions shooting, and exhibits light curve modulation with the shortest modulation Period=0.468002 ever observed. The result detect small but definite modification in temperature and mean radius of the star itself. All results are compared with previously published literature values and discussed.

  6. Radiation Dose-Rate Extraction from the Camera Image of Quince 2 Robot System using Optical Character Recognition

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    In the case of the Japanese Quince 2 robot system, 7 CCD/CMOS cameras were used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. The Quince 2 robot measured radiation in the unit 2 reactor building refueling floor of the Fukushima nuclear power plant. The CCD camera with wide field-of-view (fisheye) lens reads indicator of the dosimeter loaded on the Quince 2 robot, which was sent to carry out investigating the unit 2 reactor building refueling floor situation. The camera image with gamma ray dose-rate information is transmitted to the remote control site via VDSL communication line. At the remote control site, the radiation information in the unit 2 reactor building refueling floor can be perceived by monitoring the camera image. To make up the radiation profile in the surveyed refueling floor, the gamma ray dose-rate information in the image should be converted to numerical value. In this paper, we extract the gamma ray dose-rate value in the unit 2 reactor building refueling floor using optical character recognition method

  7. Performance Investigation of Low-Speed Electric Vehicles%低速电动汽车的性能研究

    Institute of Scientific and Technical Information of China (English)

    吴正斌; 胡坚耀; 李程宇

    2015-01-01

    电动汽车是解决能源危机和环境污染的有效方法,但就目前情况来看,电动汽车大规模使用仍需时日。尽管如此,低速电动汽车目前已在中国低端电动汽车市场取得了成功。文章探讨了低速电动汽车的行驶特性、动态性能、电池性能和能量效率。通过底盘测功机实验测试与室外道路实验,分析了低速电动汽车的负载特性和过载特性,研究不同电池对低速电动车性价比的影响。虽然目前锂离子电池比铅酸电池成本更高,但实际应用中,锂离子电池效率更高、全寿命行驶距离更长。直流驱动电机有优秀的过载能力,但电机系统的低效率限制了低速电动汽车的整车能量效率。因此,开发低成本、高效率的电池及电机驱动系统是提高低速电动车性价比的有效途径。%Electric vehicle is an effective solution to the fossil fuel energy resource crisis and environmental pollution, but there is a wide gap between current market conditions and the anticipated products. However, low-speed electric vehicles have been commercially successful in the low-end performance electric vehicle market in China. In this paper, the ride characteristics, dynamic performance, battery performance, and power efficiency of a low-speed electric vehicle were examined. The vehicle characteristics were measured through dynamometer and road tests. The overload performance was also tested under the drive power more than 4 times the rated value. The effects of different batteries on the cost performance of low-speed electric vehicles were also analysed. Although the lithium-ion polymer battery is currently more costly than the lead-acid battery, the increased efifciency of this battery provides a more economical full-cycle lifetime driving distance for practical applications. The low power efifciency of the DC drive motor and its control system limit the general power efifciency of the low-speed

  8. Design and evaluation of a high-performance charge coupled device camera for astronomical imaging

    Science.gov (United States)

    Shang, Yuanyuan; Zhang, Jie; Guan, Yong; Zhang, Weigong; Pan, Wei; Liu, Hui

    2009-10-01

    The Space Solar Telescope (SST) is the first Chinese space astronomy mission. This paper introduces the design of a high-performance 2K × 2K charge coupled device (CCD) camera that is an important payload in the Space Solar Telescope. The camera is composed of an analogue system and a digital embedded system. The analogue system is first discussed in detail, including the power and bias voltage supply circuit, power protection unit, CCD clock driver circuit, 16 bit A/D converter and low-noise amplifier circuit. The digital embedded system integrated with an NIOS II soft-core processor serves as the control and data acquisition system of the camera. In addition, research on evaluation methods for CCDs was carried out to evaluate the performance of the TH7899 CCD camera in relation to the requirements of the SST project. We present the evaluation results, including readout noise, linearity, quantum efficiency, dark current, full-well capacity, charge transfer efficiency and gain. The results show that this high-performance CCD camera can satisfy the specifications of the SST project.

  9. Monitoring performance of the cameras under the high dose-rate gamma ray environments.

    Science.gov (United States)

    Cho, Jai Wan; Choi, Young Soo; Jeong, Kyung Min

    2014-05-01

    CCD/CMOS cameras, loaded on a robot system, are generally used as the eye of the robot and monitoring unit. A major problem that arises when dealing with images provided by CCD/CMOS cameras under severe accident situations of a nuclear power plant is the presence of speckles owing to the high dose-rate gamma irradiation fields. To use a CCD/CMOS camera as a monitoring unit in a high radiation area, the legibility of the camera image in such intense gamma-radiation fields should therefore be defined. In this paper, the authors describe the monitoring index as a figure of merit of the camera's legibleness under a high dose-rate gamma ray irradiation environment. From a low dose-rate (10 Gy h) to a high dose-rate (200 Gy h) level, the legible performances of the cameras owing to the speckles are evaluated. The numbers of speckles generated by gamma ray irradiation in the camera image are calculated by an image processing technique. The legibility of the sensor indicator (thermo/hygrometer) owing to the number of speckles is also presented.

  10. Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection.

    Science.gov (United States)

    Chai, Kil-Byoung; Bellan, Paul M

    2013-12-01

    An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 10(6) frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs.

  11. Interconnected network of cameras

    Science.gov (United States)

    Hosseini Kamal, Mahdad; Afshari, Hossein; Leblebici, Yusuf; Schmid, Alexandre; Vandergheynst, Pierre

    2013-02-01

    The real-time development of multi-camera systems is a great challenge. Synchronization and large data rates of the cameras adds to the complexity of these systems as well. The complexity of such system also increases as the number of their incorporating cameras increases. The customary approach to implementation of such system is a central type, where all the raw stream from the camera are first stored then processed for their target application. An alternative approach is to embed smart cameras to these systems instead of ordinary cameras with limited or no processing capability. Smart cameras with intra and inter camera processing capability and programmability at the software and hardware level will offer the right platform for distributed and parallel processing for multi- camera systems real-time application development. Inter camera processing requires the interconnection of smart cameras in a network arrangement. A novel hardware emulating platform is introduced for demonstrating the concept of the interconnected network of cameras. A methodology is demonstrated for the interconnection network of camera construction and analysis. A sample application is developed and demonstrated.

  12. Dynamic Mapping of Rice Growth Parameters Using HJ-1 CCD Time Series Data

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2016-11-01

    Full Text Available The high temporal resolution (4-day charge-coupled device (CCD cameras onboard small environment and disaster monitoring and forecasting satellites (HJ-1A/B with 30 m spatial resolution and large swath (700 km have substantially increased the availability of regional clear sky optical remote sensing data. For the application of dynamic mapping of rice growth parameters, leaf area index (LAI and aboveground biomass (AGB were considered as plant growth indicators. The HJ-1 CCD-derived vegetation indices (VIs showed robust relationships with rice growth parameters. Cumulative VIs showed strong performance for the estimation of total dry AGB. The cross-validation coefficient of determination ( R C V 2 was increased by using two machine learning methods, i.e., a back propagation neural network (BPNN and a support vector machine (SVM compared with traditional regression equations of LAI retrieval. The LAI inversion accuracy was further improved by dividing the rice growth period into before and after heading stages. This study demonstrated that continuous rice growth monitoring over time and space at field level can be implemented effectively with HJ-1 CCD 10-day composite data using a combination of proper VIs and regression models.

  13. Autofocus method for scanning remote sensing cameras.

    Science.gov (United States)

    Lv, Hengyi; Han, Chengshan; Xue, Xucheng; Hu, Changhong; Yao, Cheng

    2015-07-10

    Autofocus methods are conventionally based on capturing the same scene from a series of positions of the focal plane. As a result, it has been difficult to apply this technique to scanning remote sensing cameras where the scenes change continuously. In order to realize autofocus in scanning remote sensing cameras, a novel autofocus method is investigated in this paper. Instead of introducing additional mechanisms or optics, the overlapped pixels of the adjacent CCD sensors on the focal plane are employed. Two images, corresponding to the same scene on the ground, can be captured at different times. Further, one step of focusing is done during the time interval, so that the two images can be obtained at different focal plane positions. Subsequently, the direction of the next step of focusing is calculated based on the two images. The analysis shows that the method investigated operates without restriction of the time consumption of the algorithm and realizes a total projection for general focus measures and algorithms from digital still cameras to scanning remote sensing cameras. The experiment results show that the proposed method is applicable to the entire focus measure family, and the error ratio is, on average, no more than 0.2% and drops to 0% by reliability improvement, which is lower than that of prevalent approaches (12%). The proposed method is demonstrated to be effective and has potential in other scanning imaging applications.

  14. Gene silencing of CCD7 and CCD8 in Phelipanche aegyptiaca by tobacco rattle virus system retarded the parasite development on the host.

    Science.gov (United States)

    Aly, Radi; Dubey, Neeraj Kumar; Yahyaa, Mosaab; Abu-Nassar, Jackline; Ibdah, Mwafaq

    2014-01-01

    Strigolactones are phytohormones that stimulate seed germination of parasitic plants including Phelipanche aegyptiaca. Strigolactones are derived from carotenoids via a pathway involving the carotenoid cleavage dioxygenases CCD7 and CCD8. We report here identification of PaCCD7 and PaCCD8 orthologous genes from P. aegyptiaca. Expression analysis of PaCCD7 and PaCCD8 genes showed significant variation in their transcript levels in seeds and tubercles of P. aegyptiaca at different developmental stages. These two parasitic PaCCD7 and PaCCD8 genes were silenced in P. aegyptiaca using a trans-silencing approach in Nicotiana benthamiana. The transient knock-down of PaCCD7 and PaCCD8 inhibited tubercle development and the infestation process in host plants. Our results suggest an important role of the strigolactone associated genes (PaCCD7 and PaCCD8) in the parasite life cycle.

  15. 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.)

  16. 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.)

  17. Vacuum Camera Cooler

    Science.gov (United States)

    Laugen, Geoffrey A.

    2011-01-01

    Acquiring cheap, moving video was impossible in a vacuum environment, due to camera overheating. This overheating is brought on by the lack of cooling media in vacuum. A water-jacketed camera cooler enclosure machined and assembled from copper plate and tube has been developed. The camera cooler (see figure) is cup-shaped and cooled by circulating water or nitrogen gas through copper tubing. The camera, a store-bought "spy type," is not designed to work in a vacuum. With some modifications the unit can be thermally connected when mounted in the cup portion of the camera cooler. The thermal conductivity is provided by copper tape between parts of the camera and the cooled enclosure. During initial testing of the demonstration unit, the camera cooler kept the CPU (central processing unit) of this video camera at operating temperature. This development allowed video recording of an in-progress test, within a vacuum environment.

  18. Constrained space camera assembly

    Science.gov (United States)

    Heckendorn, Frank M.; Anderson, Erin K.; Robinson, Casandra W.; Haynes, Harriet B.

    1999-01-01

    A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras.

  19. Novel CCD image processor for Z-plane architecture

    Science.gov (United States)

    Kemeny, S. E.; Eid, E.-S.; Fossum, E. R.

    1989-09-01

    The use of charge-coupled device (CCD) circuits in Z-plane architectures for focal-plane image processing is discussed. The low-power, compact layout nature of CCDs makes them attractive for Z-plane application. Three application areas are addressed: non-uniformity compensation using CCD MDAC circuits, neighborhood image processing functions implemented with CCD circuits, and the use of CCDs for buffering multiple image frames. Such buffering enables spatial-temporal image transformation for lossless compression.

  20. 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...

  1. Digital Pinhole Camera

    Science.gov (United States)

    Lancor, Rachael; Lancor, Brian

    2014-01-01

    In this article we describe how the classic pinhole camera demonstration can be adapted for use with digital cameras. Students can easily explore the effects of the size of the pinhole and its distance from the sensor on exposure time, magnification, and image quality. Instructions for constructing a digital pinhole camera and our method for…

  2. ROSA: a high cadence, synchronized multi-camera solar imaging system

    CERN Document Server

    Jess, D B; Christian, D J; Keenan, F P; Ryans, R S I; Crockett, P J

    2009-01-01

    Rapid Oscillations in the Solar Atmosphere (ROSA) is a synchronized, six camera high cadence solar imaging instrument developed by Queen's University Belfast. The system is available on the Dunn Solar Telescope at the National Solar Observatory in Sunspot, New Mexico, USA as a common-user instrument. Consisting of six 1k x 1k Peltier-cooled frame-transfer CCD cameras with very low noise (0.02-15 e/s/pixel), each ROSA camera is capable of full-chip readout speeds in excess of 30 Hz, or 200 Hz when the CCD is windowed. Combining multiple cameras and fast readout rates, ROSA will accumulate approximately 12 TB of data per 8 hours observing. Following successful commissioning during August 2008, ROSA will allow multi-wavelength studies of the solar atmosphere at high temporal resolution.

  3. Auto-Guiding System for CQUEAN (Camera for QUasars in EArly uNiverse)

    CERN Document Server

    Kim, Eunbin; Jeong, Hyenju; Kim, Jinyoung; Kuehne, John; Kim, Dong Han; Kim, Han Geun; Odons, Peter S; Chang, Seunghyuk; Im, Myungshin; Pak, Soojong

    2011-01-01

    To perform imaging observation of optically red objects such as high redshift quasars and brown dwarfs, the Center for the Exploration of the Origin of the Universe (CEOU) recently developed an optical CCD camera, Camera for QUasars in EArly uNiverse(CQUEAN), which is sensitive at 0.7-1.1 um. To enable observations with long exposures, we developed an auto-guiding system for CQUEAN. This system consist of an off-axis mirror, a baffle, a CCD camera, a motor and a differential decelerator. To increase the number of available guiding stars, we designed a rotating mechanism for the off-axis guiding camera. The guiding field can be scammed along the 10 acrmin ring offset from the optical axis of the telescope. Combined with the auto-guiding software of the McDonald Observatory, we confirmed that a stable image can be obtained with an exposure time as long as 1200 seconds.

  4. Development of low-noise CCD drive electronics for the world space observatory ultraviolet spectrograph subsystem

    Science.gov (United States)

    Salter, Mike; Clapp, Matthew; King, James; Morse, Tom; Mihalcea, Ionut; Waltham, Nick; Hayes-Thakore, Chris

    2016-07-01

    World Space Observatory Ultraviolet (WSO-UV) is a major Russian-led international collaboration to develop a large space-borne 1.7 m Ritchey-Chrétien telescope and instrumentation to study the universe at ultraviolet wavelengths between 115 nm and 320 nm, exceeding the current capabilities of ground-based instruments. The WSO Ultraviolet Spectrograph subsystem (WUVS) is led by the Institute of Astronomy of the Russian Academy of Sciences and consists of two high resolution spectrographs covering the Far-UV range of 115-176 nm and the Near-UV range of 174-310 nm, and a long-slit spectrograph covering the wavelength range of 115-305 nm. The custom-designed CCD sensors and cryostat assemblies are being provided by e2v technologies (UK). STFC RAL Space is providing the Camera Electronics Boxes (CEBs) which house the CCD drive electronics for each of the three WUVS channels. This paper presents the results of the detailed characterisation of the WUVS CCD drive electronics. The electronics include a novel high-performance video channel design that utilises Digital Correlated Double Sampling (DCDS) to enable low-noise readout of the CCD at a range of pixel frequencies, including a baseline requirement of less than 3 electrons rms readout noise for the combined CCD and electronics system at a readout rate of 50 kpixels/s. These results illustrate the performance of this new video architecture as part of a wider electronics sub-system that is designed for use in the space environment. In addition to the DCDS video channels, the CEB provides all the bias voltages and clocking waveforms required to operate the CCD and the system is fully programmable via a primary and redundant SpaceWire interface. The development of the CEB electronics design has undergone critical design review and the results presented were obtained using the engineering-grade electronics box. A variety of parameters and tests are included ranging from general system metrics, such as the power and mass

  5. A cost-effective 100-Gb/s transmitter with low-speed optoelectronic devices and high spectral efficiency

    Institute of Scientific and Technical Information of China (English)

    Junming Gao; Qingjiang Chang; Tao Wang; Yikai Su

    2008-01-01

    A 100-Gb/s high-speed optical transmitter is proposed and experimentally demonstrated. Based on frequency-quadrupling technique, two sub-channels with a fixed 50-GHz spacing are obtained from one laser source. Using return-to-zero differential quadrature phase-shift keying (RZ-DQPSK) modulation format and polarization multiplexing (PolMux), only low-speed electronic devices of 12.5 GHz are needed for the 100-Gb/s transmitter. This eliminates the need of ultrahigh-speed optoelectronic devices and thus greatly reduces the cost. The experimental results show that this transmitter can achieve good performance in dispersion tolerance of a 25-km single mode fiber (SMF).

  6. The design and analysis of simple low speed flap systems with the aid of linearized theory computer programs

    Science.gov (United States)

    Carlson, Harry W.

    1985-01-01

    The purpose here is to show how two linearized theory computer programs in combination may be used for the design of low speed wing flap systems capable of high levels of aerodynamic efficiency. A fundamental premise of the study is that high levels of aerodynamic performance for flap systems can be achieved only if the flow about the wing remains predominantly attached. Based on this premise, a wing design program is used to provide idealized attached flow camber surfaces from which candidate flap systems may be derived, and, in a following step, a wing evaluation program is used to provide estimates of the aerodynamic performance of the candidate systems. Design strategies and techniques that may be employed are illustrated through a series of examples. Applicability of the numerical methods to the analysis of a representative flap system (although not a system designed by the process described here) is demonstrated in a comparison with experimental data.

  7. A simulation study of the low-speed characteristics of a light twin with an engine-out

    Science.gov (United States)

    Stewart, E. C.; Moul, T. M.; Brown, P. W.

    1983-01-01

    Potential safety advantages provided by the two engines on a light twin aircraft are not realized in practice as evidenced by recent engine-failure accident statistics. These statistics showed twice the fatality rate from engine failure for twins as for single-engine aircraft. The statistics showed also that one-half of the fatal engine-out accidents involved a stall. An improvement of the low-speed engine-out characteristics is, therefore, needed. An investigation of the engine-out characteristics of light twin-engine aircraft is currently being conducted as part of the comprehensive stall/spin program for general aviation aircraft. The present study is concerned with the first phase of this program. The primary objective of this study is to advance the understanding of the basic flight dynamics and piloting problems for an engine-out condition. An all-digital computer system was used in the conducted simulation study.

  8. Development of the Seeding System Used for Laser Velocimeter Surveys of the NASA Low-Speed Centrifugal Compressor Flow Field

    Science.gov (United States)

    Wasserbauer, C. A.; Hathaway, M. D.

    1994-01-01

    Consideration is given to an atomizer-based system for distributing high-volume rates of polystyrene latex (PSL) seed material developed to support laser velocimeter investigations of the NASA Low-Speed Compressor flow field. Complete evaporation of the liquid carrier before the flow entering the compressor was of primary concern for the seeder system design. It is argued that the seed nozzle should incorporate a needle valve that can mechanically dislodge accumulated PSL seed material when the nozzle is turned off. Water is less expensive as the liquid carrier and should be used whenever adequate residence times are available to ensure complete evaporation. PSL agglomerates over time and needs to be mixed or blended before use. Arrangement of the spray nozzles needs to be adjustable to provide maximum seeding at the laser probe volume.

  9. Fractional-Order Generalized Predictive Control: Application for Low-Speed Control of Gasoline-Propelled Cars

    Directory of Open Access Journals (Sweden)

    M. Romero

    2013-01-01

    Full Text Available There is an increasing interest in using fractional calculus applied to control theory generalizing classical control strategies as the PID controller and developing new ones with the intention of taking advantage of characteristics supplied by this mathematical tool for the controller definition. In this work, the fractional generalization of the successful and spread control strategy known as model predictive control is applied to drive autonomously a gasoline-propelled vehicle at low speeds. The vehicle is a Citroën C3 Pluriel that was modified to act over the throttle and brake pedals. Its highly nonlinear dynamics are an excellent test bed for applying beneficial characteristics of fractional predictive formulation to compensate unmodeled dynamics and external disturbances.

  10. A low-speed wind tunnel study of vortex interaction control techniques on a chine-forebody/delta-wing configuration

    Science.gov (United States)

    Rao, Dhanvada M.; Bhat, M. K.

    1992-01-01

    A low speed wind tunnel evaluation was conducted of passive and active techniques proposed as a means to impede the interaction of forebody chine and delta wing vortices, when such interaction leads to undesirable aerodynamic characteristics particularly in the post stall regime. The passive method was based on physically disconnecting the chine/wing junction; the active technique employed deflection of inboard leading edge flaps. In either case, the intent was to forcibly shed the chine vortices before they encountered the downwash of wing vortices. Flow visualizations, wing pressures, and six component force/moment measurements confirmed the benefits of forced vortex de-coupling at post stall angles of attack and in sideslip, viz., alleviation of post stall zero beta asymmetry, lateral instability and twin tail buffet, with insignificant loss of maximum lift.

  11. Integrated Condition Monitoring and Prognosis Method for Incipient Defect Detection and Remaining Life Prediction of Low Speed Slew Bearings

    Directory of Open Access Journals (Sweden)

    Wahyu Caesarendra

    2017-04-01

    Full Text Available This paper presents an application of multivariate state estimation technique (MSET, sequential probability ratio test (SPRT and kernel regression for low speed slew bearing condition monitoring and prognosis. The method is applied in two steps. Step (1 is the detection of the incipient slew bearing defect. In this step, combined MSET and SPRT is used with circular-domain kurtosis, time-domain kurtosis, wavelet decomposition (WD kurtosis, empirical mode decomposition (EMD kurtosis and the largest Lyapunov exponent (LLE feature. Step (2 is the prediction of the selected features’ trends and the estimation of the remaining useful life (RUL of the slew bearing. In this step, kernel regression is used with time-domain kurtosis, WD kurtosis and the LLE feature. The application of the method is demonstrated with laboratory slew bearing acceleration data.

  12. Laser Anemometer Measurements of the Three-Dimensional Rotor Flow Field in the NASA Low-Speed Centrifugal Compressor

    Science.gov (United States)

    Hathaway, Michael D.; Chriss, Randall M.; Strazisar, Anthony J.; Wood, Jerry R.

    1995-01-01

    A laser anemometer system was used to provide detailed surveys of the three-dimensional velocity field within the NASA low-speed centrifugal impeller operating with a vaneless diffuser. Both laser anemometer and aerodynamic performance data were acquired at the design flow rate and at a lower flow rate. Floor path coordinates, detailed blade geometry, and pneumatic probe survey results are presented in tabular form. The laser anemometer data are presented in the form of pitchwise distributions of axial, radial, and relative tangential velocity on blade-to-blade stream surfaces at 5-percent-of-span increments, starting at 95-percent-of-span from the hub. The laser anemometer data are also presented as contour and wire-frame plots of throughflow velocity and vector plots of secondary velocities at all measurement stations through the impeller.

  13. Sensitivity Analysis of Heavy Fuel Oil Spray and Combustion under Low-Speed Marine Engine-Like Conditions

    Directory of Open Access Journals (Sweden)

    Lei Zhou

    2017-08-01

    Full Text Available On account of their high power, thermal efficiency, good reliability, safety, and durability, low-speed two-stroke marine diesel engines are used as the main drive devices for large fuel and cargo ships. Most marine engines use heavy fuel oil (HFO as the primary fuel, however, the physical and chemical characteristics of HFO are not clear because of its complex thermophysical properties. The present study was conducted to investigate the effects of fuel properties on the spray and combustion characteristics under two-stroke marine engine-like conditions via a sensitivity analysis. The sensitivity analysis of fuel properties for non-reacting and reacting simulations are conducted by comparing two fuels having different physical properties, such as fuel density, dynamic viscosity, critical temperature, and surface tension. The performances of the fuels are comprehensively studied under different ambient pressures, ambient temperatures, fuel temperatures, and swirl flow conditions. From the results of non-reacting simulations of HFO and diesel fuel properties in a constant volume combustion chamber, it can be found that the increase of the ambient pressure promotes fuel evaporation, resulting in a reduction in the steady liquid penetration of both diesel and HFO; however, the difference in the vapor penetrations of HFO and diesel reduces. Increasing the swirl flow significantly influences the atomization of both HFO and diesel, especially the liquid distribution of diesel. It is also found that the ambient temperature and fuel temperature have the negative effects on Sauter mean diameter (SMD distribution. For low-speed marine engines, the combustion performance of HFO is not sensitive to activation energy in a certain range of activation energy. At higher engine speed, the difference in the effects of different activation energies on the in-cylinder pressure increases. The swirl flow in the cylinder can significantly promote fuel evaporation and

  14. A charge coupled device camera with electron decelerator for intermediate voltage electron microscopy.

    Science.gov (United States)

    Downing, Kenneth H; Mooney, Paul E

    2008-04-01

    Electron microscopists are increasingly turning to intermediate voltage electron microscopes (IVEMs) operating at 300-400 kV for a wide range of studies. They are also increasingly taking advantage of slow-scan charge coupled device (CCD) cameras, which have become widely used on electron microscopes. Under some conditions, CCDs provide an improvement in data quality over photographic film, as well as the many advantages of direct digital readout. However, CCD performance is seriously degraded on IVEMs compared to the more conventional 100 kV microscopes. In order to increase the efficiency and quality of data recording on IVEMs, we have developed a CCD camera system in which the electrons are decelerated to below 100 kV before impacting the camera, resulting in greatly improved performance in both signal quality and resolution compared to other CCDs used in electron microscopy. These improvements will allow high-quality image and diffraction data to be collected directly with the CCD, enabling improvements in data collection for applications including high-resolution electron crystallography, single particle reconstruction of protein structures, tomographic studies of cell ultrastructure, and remote microscope operation. This approach will enable us to use even larger format CCD chips that are being developed with smaller pixels.

  15. Programmable Clock Waveform Generation for CCD Readout

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, J. de; Castilla, J.; Martinez, G.; Marin, J.

    2006-07-01

    Charge transfer efficiency in CCDs is closely related to the clock waveform. In this paper, an experimental framework to explore different FPGA based clock waveform generator designs is described. Two alternative design approaches for controlling the rise/fall edge times and pulse width of the CCD clock signal have been implemented: level-control and time-control. Both approaches provide similar characteristics regarding the edge linearity and noise. Nevertheless, dissimilarities have been found with respect to the area and frequency range of application. Thus, while the time-control approach consumes less area, the level control approach provides a wider range of clock frequencies since it does not suffer capacitor discharge effect. (Author) 8 refs.

  16. EUV astronomical spectroscopy with CCD detectors

    Science.gov (United States)

    Stern, R. A.; Catura, R. C.; Blouke, M. M.; Winzenread, M.

    1986-01-01

    The applicability of CCD detectors to astronomical extreme ultraviolet (EUV) spectroscopy (100-1250 A) is discussed. The advantages of CCDs in this spectral region include internal electron yield, the potential for very high quantum efficiency (about 50-90 percent), and broad wavelength response. Visible light suppression is achieved by a combination of low grating scattering, greater than unity electron yield in the EUV, and various filter techniques. For the current generation of CCDs, detection of only a few EUV photons will rapidly overwhelm the read noise; thus, for all practical S/N ratios used in astronomical spectroscopy, read noise will be negligible compared to the poisson statistics of the detected photons. A model based on experimental data for the quantum efficiency and electron yield of CCDs in the EUV is discussed.

  17. Resolved CCD Photometry of Pluto and Charon

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.H.; Waddell, P.; Christian, C.A.

    1988-04-01

    Highly resolved CCD images of Pluto and Charon near maximum separation are measured with point spread function fitting techniques to determine independent magnitudes and an accurate separation for Pluto and Charon. A measured separation of 0.923 + or - 0.005 arcsec at a position angle of 173.3 + or - 0.3 deg on June 18, 1987 UT produced a value of 19558.0 + or - 153.0 km for the radius of Charon's orbit. An apparent B magnitude of 14.877 + or - 0.009 and (B-I) color of 1.770 + or - 0.015 are determined for Pluto, while Charon is fainter with B = 18.826 + or - 0.011 and slightly bluer with (B-I) = 1.632 + or - 0.018. 18 references.

  18. New CCD photometry of asteroid (1028) Lydina

    Institute of Scientific and Technical Information of China (English)

    Yi-Bo Wang; Xiao-Bin Wang

    2012-01-01

    New CCD photometric observations for asteroid (1028) Lydina,carried out with the 1-m and 2.4-m telescopes at Yunnan Observatory from 2011 December 19 to 2012 February 3,are presented.Using the new light curves,the rotation period of 11.680±0.001 hours is derived with the Phase Dispersion Minimization (PDM) method.In addition,using the Amplitude-Aspect method,the elementary results of the pole orientation of asteroid (1028) Lydina are obtained:λp= 111°+4°-4°,βp= 31°+4°-5°.Meanwhile,the axial ratios of the tri-axial ellipsoid are estimated:a/b = 1.77+0.10-0.08and b/c = 1.17+0.07-0.09.

  19. Is Low Speed Electric Vehicle a Disruptive Innovation?%低速电动汽车是破坏性创新吗

    Institute of Scientific and Technical Information of China (English)

    张长令; 王丽萍

    2013-01-01

    Low speed electric vehicle is a special economic phenomenon in China Low speed electric vehicle develops rapidly since 2005. Currently, the development of low speed electric vehicle industry in China has entered the key stage of industrialization. Because of the characteristics of disruptive product, low speed electric vehicle is usually attributed to disruptive innovation pointing to traditional automobile. Based on disruptive innovation theory, connecting with current situation of low speed electric vehicle industry in China, this paper analyzes the challenges on disruptive innovation theory brought by low speed electric vehicle industry. The analysis indicated that low speed electric vehicle is not a disruptive product to traditional automobile.%低速电动汽车是中国特有的经济现象.中国低速电动汽车产业自2005年以来开始快速发展,目前已进入产业化的关键阶段.由于具有破坏性产品的特点,低速电动汽车往往被归结为针对传统汽车的破坏性创新.本文在破坏性创新理论的基础上,结合低速中国电动汽车产业发展的特点,深入分析了低速电动汽车产业发展对破坏性创新理论带来的挑战.分析表明,低速电动汽车并非传统汽车的破坏性产品.

  20. Measurement of 3D Displacement fields using 3D Laser and CCD Camera

    OpenAIRE

    Rahel, Rahel; Mahmud, Mussa; Michael, Roy; Fontaine, Jean François

    2013-01-01

    International audience; Many applications dealing with the mechanical behavior of materials require the measurement of displacement fields or deformation fields. For this type of measurement, optical methods have become unavoidable due to their non-intrusive approach, their high spatial resolution, their high sensitivity, the large size of their examinated field, and the increasing power of the computers that now allow the processing of huge quantities of data. In this context we have develop...

  1. On Relativistic Disk Spectroscopy in Compact Objects with X-ray CCD Cameras

    CERN Document Server

    Miller, J M; Bautz, M W; Bhattacharyya, S; Burrows, D N; Cackett, E M; Fabian, A C; Freyberg, M J; Haberl, F; Kennea, J; Nowak, M A; Reis, R C; Strohmayer, T E; Tsujimoto, M

    2010-01-01

    X-ray charge-coupled devices (CCDs) are the workhorse detectors of modern X-ray astronomy. Typically covering the 0.3-10.0 keV energy range, CCDs are able to detect photoelectric absorption edges and K shell lines from most abundant metals. New CCDs also offer resolutions of 30-50 (E/dE), which is sufficient to detect lines in hot plasmas and to resolve many lines shaped by dynamical processes in accretion flows. The spectral capabilities of X-ray CCDs have been particularly important in detecting relativistic emission lines from the inner disks around accreting neutron stars and black holes. One drawback of X-ray CCDs is that spectra can be distorted by photon "pile-up", wherein two or more photons may be registered as a single event during one frame time. We have conducted a large number of simulations using a statistical model of photon pile-up to assess its impacts on relativistic disk line and continuum spectra from stellar-mass black holes and neutron stars. The simulations cover the range of current X-...

  2. Design and test of optoelectronic system of alignment control based on CCD camera

    Science.gov (United States)

    Anisimov, A. G.; Gorbachyov, A. A.; Krasnyashchikh, A. V.; Pantushin, A. N.; Timofeev, A. N.

    2008-10-01

    In this work, design, implementation and test of a system intended for positioning of the elements of turbine units relative to the line of shaft with high precision, are discussed. A procedure of the conversion of coordinates from the instrument system into the system connected with the practical position of the axis of turbine has been devised. It is shown that optoelectronic systems of aligment built by autoreflexive scheme can be used for high precision measurements.

  3. Fast measurement of temporal noise of digital camera's photosensors

    Science.gov (United States)

    Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Rostislav S.; Starikov, Sergey N.

    2015-10-01

    Currently photo- and videocameras are widespread parts of both scientific experimental setups and consumer applications. They are used in optics, radiophysics, astrophotography, chemistry, and other various fields of science and technology such as control systems and video-surveillance monitoring. One of the main information limitations of photoand videocameras are noises of photosensor pixels. Camera's photosensor noise can be divided into random and pattern components. Temporal noise includes random noise component while spatial noise includes pattern noise component. Spatial part usually several times lower in magnitude than temporal. At first approximation spatial noises might be neglected. Earlier we proposed modification of the automatic segmentation of non-uniform targets (ASNT) method for measurement of temporal noise of photo- and videocameras. Only two frames are sufficient for noise measurement with the modified method. In result, proposed ASNT modification should allow fast and accurate measurement of temporal noise. In this paper, we estimated light and dark temporal noises of four cameras of different types using the modified ASNT method with only several frames. These cameras are: consumer photocamera Canon EOS 400D (CMOS, 10.1 MP, 12 bit ADC), scientific camera MegaPlus II ES11000 (CCD, 10.7 MP, 12 bit ADC), industrial camera PixeLink PLB781F (CMOS, 6.6 MP, 10 bit ADC) and video-surveillance camera Watec LCL-902C (CCD, 0.47 MP, external 8 bit ADC). Experimental dependencies of temporal noise on signal value are in good agreement with fitted curves based on a Poisson distribution excluding areas near saturation. We measured elapsed time for processing of shots used for temporal noise estimation. The results demonstrate the possibility of fast obtaining of dependency of camera full temporal noise on signal value with the proposed ASNT modification.

  4. Development and validation of a CCD-laser aerosol detective system for measuring the ambient aerosol phase function

    Directory of Open Access Journals (Sweden)

    Y. Bian

    2017-06-01

    Full Text Available Aerosol phase function represents the angular scattering property of aerosols, which is crucial for understanding the climate effects of aerosols that have been identified as one of the largest uncertainties in the evaluation of radiative forcing. So far, there is a lack of instruments with which to measure the aerosol phase function directly and accurately in laboratory studies and in situ measurements. A portable instrument with high angular range and resolution has been developed for the measurement of the phase function of ambient aerosols in this study. The charge-coupled device-laser aerosol detective system (CCD-LADS measures the aerosol phase function both across a relatively wide angular range of 10–170° and at a high resolution of 0.1°. The system includes a continuous laser, two charge-coupled device cameras and the corresponding fisheye lenses. The CCD-LADS was validated by both a laboratory study and a field measurement. The comparison between the aerosol phase function retrieved from CCD-LADS and Mie-scattering model shows good agreement. Compared with the TSI polar nephelometer, CCD-LADS has the advantages of wider detection range and better stability.

  5. World's fastest and most sensitive astronomical camera

    Science.gov (United States)

    2009-06-01

    The next generation of instruments for ground-based telescopes took a leap forward with the development of a new ultra-fast camera that can take 1500 finely exposed images per second even when observing extremely faint objects. The first 240x240 pixel images with the world's fastest high precision faint light camera were obtained through a collaborative effort between ESO and three French laboratories from the French Centre National de la Recherche Scientifique/Institut National des Sciences de l'Univers (CNRS/INSU). Cameras such as this are key components of the next generation of adaptive optics instruments of Europe's ground-based astronomy flagship facility, the ESO Very Large Telescope (VLT). ESO PR Photo 22a/09 The CCD220 detector ESO PR Photo 22b/09 The OCam camera ESO PR Video 22a/09 OCam images "The performance of this breakthrough camera is without an equivalent anywhere in the world. The camera will enable great leaps forward in many areas of the study of the Universe," says Norbert Hubin, head of the Adaptive Optics department at ESO. OCam will be part of the second-generation VLT instrument SPHERE. To be installed in 2011, SPHERE will take images of giant exoplanets orbiting nearby stars. A fast camera such as this is needed as an essential component for the modern adaptive optics instruments used on the largest ground-based telescopes. Telescopes on the ground suffer from the blurring effect induced by atmospheric turbulence. This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it blurs the finest details of the images. Adaptive optics techniques overcome this major drawback, so that ground-based telescopes can produce images that are as sharp as if taken from space. Adaptive optics is based on real-time corrections computed from images obtained by a special camera working at very high speeds. Nowadays, this means many hundreds of times each second. The new generation instruments require these

  6. Control and protection of outdoor embedded camera for astronomy

    Science.gov (United States)

    Rigaud, F.; Jegouzo, I.; Gaudemard, J.; Vaubaillon, J.

    2012-09-01

    The purpose of CABERNET- Podet-Met (CAmera BEtter Resolution NETwork, Pole sur la Dynamique de l'Environnement Terrestre - Meteor) project is the automated observation, by triangulation with three cameras, of meteor showers to perform a calculation of meteoroids trajectory and velocity. The scientific goal is to search the parent body, comet or asteroid, for each observed meteor. To install outdoor cameras in order to perform astronomy measurements for several years with high reliability requires a very specific design for the box. For these cameras, this contribution shows how we fulfilled the various functions of their boxes, such as cooling of the CCD, heating to melt snow and ice, the protecting against moisture, lightning and Solar light. We present the principal and secondary functions, the product breakdown structure, the technical solutions evaluation grid of criteria, the adopted technology products and their implementation in multifunction subsets for miniaturization purpose. To manage this project, we aim to get the lowest manpower and development time for every part. In appendix, we present the measurements the image quality evolution during the CCD cooling, and some pictures of the prototype.

  7. 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.

  8. Microchannel plate streak camera

    Science.gov (United States)

    Wang, Ching L.

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  9. 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.

  10. Low-speed impact simulations into regolith in support of asteroid sampling mechanism design I: Comparison with 1-g experiments

    Science.gov (United States)

    Schwartz, Stephen R.; Michel, Patrick; Richardson, Derek C.; Yano, Hajime

    2014-11-01

    This study is carried out in the framework of sample-return missions to asteroids that use a low-speed projectile as the primary component of its sampling mechanism (e.g., JAXA's Hayabusa and Hayabusa2 missions). We perform numerical simulations of such impacts into granular materials using different projectile shapes under Earth's gravity. We then compare the amounts of ejected mass obtained in our simulations against what was found in experiments that used similar setups, which allows us to validate our numerical approach. We then investigate the sensitivity of various parameters involved in the contacts between grains on the amount of mass that is ejected. For the targets, we consider 2 different monodisperse grain-diameter sizes: 5 mm and 3 mm. The impact speed of the projectile is 11 m s-1, and is directed downward, perpendicular to the surface of the targets. Using an implementation of the soft-sphere discrete element method (SSDEM) in the N-body gravity tree code pkdgrav, previously validated in the context of low-speed impacts into sintered glass bead agglomerates, we find a noticeable dependence of the amount of ejected mass on the projectile shape. As found in experiments, in the case of the larger target grain size (5 mm), a conically shaped projectile ejects a greater amount of mass than do projectiles of other shapes, including disks and spheres. We then find that numerically the results are sensitive to the normal coefficient of restitution of the grains, especially for impacts into targets comprising smaller grains (3 mm). We also find that static friction plays a more important role for impacts into targets comprising the larger grains. As a preliminary demonstration, one of these considered setups is simulated in a microgravity environment. As expected, a reduction in gravity increases both the amount of ejected mass and the timescale of the impact process. A dedicated quantitative study in microgravity is the subject of future work. We also plan

  11. Camera simulation engine enables efficient system optimization for super-resolution imaging

    Science.gov (United States)

    Fullerton, Stephanie; Bennett, Keith; Toda, Eiji; Takahashi, Teruo

    2012-02-01

    Quantitative fluorescent imaging requires optimization of the complete optical system, from the sample to the detector. Such considerations are especially true for precision localization microscopy such as PALM and (d)STORM where the precision of the result is limited by the noise in both the optical and detection systems. Here, we present a Camera Simulation Engine (CSE) that allows comparison of imaging results from CCD, CMOS and EM-CCD cameras under various sample conditions and can accurately validate the quality of precision localization algorithms and camera performance. To achieve these results, the CSE incorporates the following parameters: 1) Sample conditions including optical intensity, wavelength, optical signal shot noise, and optical background shot noise; 2) Camera specifications including QE, pixel size, dark current, read noise, EM-CCD excess noise; 3) Camera operating conditions such as exposure, binning and gain. A key feature of the CSE is that, from a single image (either real or simulated "ideal") we generate a stack of statistically realistic images. We have used the CSE to validate experimental data showing that certain current scientific CMOS technology outperforms EM-CCD in most super-resolution scenarios. Our results support using the CSE to efficiently and methodically select cameras for quantitative imaging applications. Furthermore, the CSE can be used to robustly compare and evaluate new algorithms for data analysis and image reconstruction. These uses of the CSE are particularly relevant to super-resolution precision localization microscopy and provide a faster, simpler and more cost effective means of system optimization, especially camera selection.

  12. Development of an n-channel CCD, CCD-NeXT1, for Soft X-ray Imager onboard the NeXT satellite

    Energy Technology Data Exchange (ETDEWEB)

    Takagi, Shin-ichiro [Hamamatsu Photonics K.K., 1126-1, Ichino-cho, Hamamatsu 435-8558 (Japan); Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: s-takagi@ssd.hpk.co.jp; Tsuru, Takeshi Go [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: tsuru@cr.scphys.kyoto-u.ac.jp; Inui, Tatsuya; Matsumoto, Hironori; Koyama, Katsuji [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Ozawa, Hideki; Tohiguchi, Masakuni; Matsuura, Daisuke; Miyata, Emi; Tsunemi, Hiroshi [Department of Earth and Space Science, Graduate School of Science, Osaka University, Machikaneyama-cho, Toyonaka-shi, Osaka 560-0043 (Japan); Miyaguchi, Kazuhisa; Maeda, Kentaro; Kohno, Hirohiko [Hamamatsu Photonics K.K., 1126-1, Ichino-cho, Hamamatsu 435-8558 (Japan)

    2007-11-21

    NeXT (New X-ray Telescope) is the next Japanese X-ray astronomical satellite mission after the Suzaku satellite. NeXT aims to perform wide band imaging spectroscopy. Due to the successful development of a multilayer coated mirror, called a supermirror, NeXT can focus X-rays in the energy range from 0.1 up to 80 keV. To cover this wide energy range, we are in the process of developing a hybrid X-ray camera, Wideband X-ray Imager (WXI) as a focal plane detector of the supermirror. The WXI consists of X-ray CCDs (SXI) and CdTe pixelized detectors (HXI), which cover the lower and higher X-ray energy bands of 0.1-80 keV, respectively. The X-ray CCDs of the SXI are stacked above the CdTe pixelized detectors of the HXI. The X-ray CCDs of the SXI detect soft X-rays below {approx}10keV and allow hard X-rays pass into the CdTe detectors of the HXI without loss. Thus, we have been developing a 'back-supportless CCD' with a thick depletion layer, a thinned silicon wafer, and a back-supportless structure. In this paper, we report the development and performances of an evaluation model of CCD for the SXI, 'CCD-NeXT1'. We successfully fabricated two types of CCD-NeXT1, unthinned CCDs with 625-{mu}m thick wafer and 150-{mu}m thick thinned CCDs. By omitting the polishing process when making the thinned CCDs, we confirmed that the polishing process does not impact the X-ray performance. In addition, we did not find significant differences in the X-ray performance between the two types of CCDs. The energy resolution and readout noise are {approx}140eV (FWHM) at 5.9 keV and {approx}5 electrons (RMS), respectively. The estimated thickness of the depletion layer is {approx}80{mu}m. The performances almost satisfy the requirements of the baseline plan of the SXI.

  13. LSST Camera Optics Design

    Energy Technology Data Exchange (ETDEWEB)

    Riot, V J; Olivier, S; Bauman, B; Pratuch, S; Seppala, L; Gilmore, D; Ku, J; Nordby, M; Foss, M; Antilogus, P; Morgado, N

    2012-05-24

    The Large Synoptic Survey Telescope (LSST) uses a novel, three-mirror, telescope design feeding a camera system that includes a set of broad-band filters and three refractive corrector lenses to produce a flat field at the focal plane with a wide field of view. Optical design of the camera lenses and filters is integrated in with the optical design of telescope mirrors to optimize performance. We discuss the rationale for the LSST camera optics design, describe the methodology for fabricating, coating, mounting and testing the lenses and filters, and present the results of detailed analyses demonstrating that the camera optics will meet their performance goals.

  14. Ringfield lithographic camera

    Science.gov (United States)

    Sweatt, William C.

    1998-01-01

    A projection lithography camera is presented with a wide ringfield optimized so as to make efficient use of extreme ultraviolet radiation from a large area radiation source (e.g., D.sub.source .apprxeq.0.5 mm). The camera comprises four aspheric mirrors optically arranged on a common axis of symmetry with an increased etendue for the camera system. The camera includes an aperture stop that is accessible through a plurality of partial aperture stops to synthesize the theoretical aperture stop. Radiation from a mask is focused to form a reduced image on a wafer, relative to the mask, by reflection from the four aspheric mirrors.

  15. Radiation events in astronomical CCD images

    Science.gov (United States)

    Smith, Alan R.; McDonald, Richard J.; Hurley, D. C.; Holland, Steven E.; Groom, Donald E.; Brown, William E.; Gilmore, David K.; Stover, Richard J.; Wei, Mingzhi

    2002-04-01

    The remarkable sensitivity of depleted silicon to ionizing radiation is a nuisance to astronomers. 'Cosmic rays' degrade images because of struck pixels, leading to modified observing strategies and the development of algorithms to remove the unwanted artifacts. In the new-generation CCD's with thick sensitive regions, cosmic-ray muons make recognizable straight tracks and there is enhanced sensitivity to ambient gamma radiation via Compton-scattered electrons ('worms'). Beta emitters inside the dewar, for example high-potassium glasses such as BK7 , also produce worm-like tracks. The cosmic-ray muon rate is irreducible and increases with altitude. The gamma rays are mostly by- products of 40K decay and the U and Th decay chains; these elements commonly appear as traces in concrete and other materials. The Compton recoil event rate can be reduced significantly by the choice of materials in the environment and dewar and by careful shielding. Telescope domes appear to have significantly lower rates than basement laboratories and Coude spectrograph rooms. Radiation sources inside the dewar can be eliminated by judicious choice of materials. Cosmogenic activation during high-altitude fights does not appear to be a problem. Our conclusion are supported by tests at the Lawrence Berkeley National Laboratory low-level counting facilities in Berkeley and at Oroville, California (180 m underground).

  16. Super CCD SR是什么

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    我最近看到富士公司新上市的数字相机FinePix S3 Pro的像素为:617万S像素,617万R像素,共1234万像素。请问:什么是S像素,什么是R像素?为什么富士的相机的像素标明S和R像素.而其它品牌的数字相机没有这样标明.富士相机的Super CCD SR传感器与其他品牌数字相机的CCD传感器相比,有什么特点?为什么总像素1234万像素;而有效像素却只有610万像素?另外。数字相机用的CMOS传感器与CCD传感器有什么异同?

  17. Experimental investigation about the effect of non-axisymmetric wake impact on a low speed axial compressor

    Science.gov (United States)

    Liu, Jianyong; Lu, Yajun; Li, Zhiping

    2010-05-01

    Non-axisymmetric wake impact experiments were carried out after the best exciting frequency for a low speed axial compressor had been found by axisymmetric wake impact experiments. When the number and circumferential distribution of inlet guide vanes (IGV) are logical the wakes of non-axisymmetric IGVs can exert beneficial unsteady exciting effect on their downstream rotor flow fields and improve the compressor’s performance. In the present paper, four non-axisymmetric wake impact plans were found working better than the axisymmetric wake impact plan. Compared with the base plan, the best non-axisymmetric plan increased the compressor’s peak efficiency, and the total pressure rise by 1.1 and 2%, and enhanced the stall margin by 4.4%. The main reason why non-axisymmetric plans worked better than the axisymmetric plan was explained as the change of the unsteady exciting signal arising from IGV wakes. Besides the high-frequency components, the non-axisymmetric plan generated a beneficial low-frequency square-wave exciting signal and other secondary frequency components. Compared with the axisymmetric plan, multi-frequency exciting wakes arising from the non-axisymmetric plans are easier to get coupling relation with complex vortices such as clearance vortices, passage vortices and shedding vortices.

  18. Algorithmic localisation of noise sources in the tip region of a low-speed axial flow fan

    Science.gov (United States)

    Tóth, Bence; Vad, János

    2017-04-01

    An objective and algorithmised methodology is proposed to analyse beamform data obtained for axial fans. Its application is demonstrated in a case study regarding the tip region of a low-speed cooling fan. First, beamforming is carried out in a co-rotating frame of reference. Then, a distribution of source strength is extracted along the circumference of the rotor at the blade tip radius in each analysed third-octave band. The circumferential distributions are expanded into Fourier series, which allows for filtering out the effects of perturbations, on the basis of an objective criterion. The remaining Fourier components are then considered as base sources to determine the blade-passage-periodic flow mechanisms responsible for the broadband noise. Based on their frequency and angular location, the base sources are grouped together. This is done using the fuzzy c-means clustering method to allow the overlap of the source mechanisms. The number of clusters is determined in a validity analysis. Finally, the obtained clusters are assigned to source mechanisms based on the literature. Thus, turbulent boundary layer - trailing edge interaction noise, tip leakage flow noise, and double leakage flow noise are identified.

  19. Analytical and Numerical Deflection Study on the Structure of 10 kW Low Speed Permanent Magnet Generator

    Directory of Open Access Journals (Sweden)

    Hilman Syaeful Alam

    2012-12-01

    Full Text Available Analytical and numerical studies of the deflection in the structure of 10 kW low speed permanent magnet generator (PMG have been discussed in this paper. This study is intended to prevent failure of the structure when the prototype is made. Numerical analysis was performed with the finite-element method (FEM. Flux density, weight and temperature of the components are the required input parameters. Deflection observed were the movements of the two main rotor components, namely the rim and shaft, where the maximum deflection allowed at the air gap between rotor and stator should be between 10% to 20% of the air gap clearance or 0.1000 mm to 0.2000 mm. Base on the analysis, total deflection of the analytic calculation was 0.0553 mm, and numerical simulation was 0.0314 mm. Both values were in the acceptable level because it was still below the maximum allowed deflection. These results indicate that the structure of a permanent magnet generator (rim and shaft can be used safely.

  20. Modeling spatial trajectories in dynamics testing using basis splines: application to tracking human volunteers in low-speed frontal impacts.

    Science.gov (United States)

    Samuels, Marina A; Reed, Matthew P; Arbogast, Kristy B; Seacrist, Thomas

    2016-01-01

    Designing motor vehicle safety systems requires knowledge of whole body kinematics during dynamic loading for occupants of varying size and age, often obtained from sled tests with postmortem human subjects and human volunteers. Recently, we reported pediatric and adult responses in low-speed (<4 g) automotive-like impacts, noting reductions in maximum excursion with increasing age. Since the time-based trajectory shape is also relevant for restraint design, this study quantified the time-series trajectories using basis splines and developed a statistical model for predicting trajectories as a function of body dimension or age. Previously collected trajectories of the head, spine, and pelvis were modeled using cubic basis splines with eight control points. A principal component analysis was conducted on the control points and related to erect seated height using a linear regression model. The resulting statistical model quantified how trajectories became shorter and flatter with increasing body size, corresponding to the validation data-set. Trajectories were then predicted for erect seated heights corresponding to pediatric and adult anthropomorphic test devices (ATDs), thus generating performance criteria for the ATDs based on human response. This statistical model can be used to predict trajectories for a subject of specified anthropometry and utilized in subject-specific computational models of occupant response.

  1. The Role of Tip Leakage Flow in Triggering Rotating Stall of a Low Speed Compressor under Inlet Distortion

    Institute of Scientific and Technical Information of China (English)

    Jingxuan Zhang; Feng Lin; Jingyi Chen; Chaoqun Nie

    2009-01-01

    The stall behavior in a single-stage low-speed axial compressor under rotating inlet distortion (RID) is investi-gated in the first half of this paper. The tests demonstrate that the tip leakage flow (TLF) plays an important rolein triggering rotating stall. The tracking of the spike-like disturbances caused by the spillage of TLV indicates that most of such spike-like disturbances will be smeared by non-distorted sector and the growth of the spike-like dis-turbances actually relate closely to how and how often the path of the propagating disturbances come across the path of the rotating distorted sector. In the second half of this paper, micro air injections are applied to test the ef-fect behavior of TLF on stall inception. Contrasts to without micro air injections, the spike-like disturbances are much fewer, so the possibilities that spike-like disturbances may trigger rotating stall are fewer too. As a result, the compressor gets a lower mass flow rate at stall for both co-rotating inlet distortion and counter-rotating inlet distortion.

  2. Analysis of a Split-Plot Experimental Design Applied to a Low-Speed Wind Tunnel Investigation

    Science.gov (United States)

    Erickson, Gary E.

    2013-01-01

    A procedure to analyze a split-plot experimental design featuring two input factors, two levels of randomization, and two error structures in a low-speed wind tunnel investigation of a small-scale model of a fighter airplane configuration is described in this report. Standard commercially-available statistical software was used to analyze the test results obtained in a randomization-restricted environment often encountered in wind tunnel testing. The input factors were differential horizontal stabilizer incidence and the angle of attack. The response variables were the aerodynamic coefficients of lift, drag, and pitching moment. Using split-plot terminology, the whole plot, or difficult-to-change, factor was the differential horizontal stabilizer incidence, and the subplot, or easy-to-change, factor was the angle of attack. The whole plot and subplot factors were both tested at three levels. Degrees of freedom for the whole plot error were provided by replication in the form of three blocks, or replicates, which were intended to simulate three consecutive days of wind tunnel facility operation. The analysis was conducted in three stages, which yielded the estimated mean squares, multiple regression function coefficients, and corresponding tests of significance for all individual terms at the whole plot and subplot levels for the three aerodynamic response variables. The estimated regression functions included main effects and two-factor interaction for the lift coefficient, main effects, two-factor interaction, and quadratic effects for the drag coefficient, and only main effects for the pitching moment coefficient.

  3. Low speed maneuvering flight of the rose-breasted cockatoo (Eolophus roseicapillus). II. Inertial and aerodynamic reorientation.

    Science.gov (United States)

    Hedrick, T L; Usherwood, J R; Biewener, A A

    2007-06-01

    The reconfigurable, flapping wings of birds allow for both inertial and aerodynamic modes of reorientation. We found evidence that both these modes play important roles in the low speed turning flight of the rose-breasted cockatoo Eolophus roseicapillus. Using three-dimensional kinematics recorded from six cockatoos making a 90 degrees turn in a flight corridor, we developed predictions of inertial and aerodynamic reorientation from estimates of wing moments of inertia and flapping arcs, and a blade-element aerodynamic model. The blade-element model successfully predicted weight support (predicted was 88+/-17% of observed, N=6) and centripetal force (predicted was 79+/-29% of observed, N=6) for the maneuvering cockatoos and provided a reasonable estimate of mechanical power. The estimated torque from the model was a significant predictor of roll acceleration (r(2)=0.55, Pflight dynamics (approximately -0.45), were required to bring our estimates of reorientation due to aerodynamic torque back into conjunction with the measured changes in orientation. Our estimates of inertial reorientation were statistically significant predictors of the measured reorientation within wingbeats (r(2) from 0.2 to 0.37, Pflight muscles: the pectoralis, supracoracoideus, biceps brachii and extensor metacarpi radialis (r(2) from 0.27 to 0.45, Pflight maneuvers rely on production of asymmetries throughout the flight apparatus rather than in a specific set of control or turning muscles.

  4. Impact coefficient and reliability of mid-span continuous beam bridge under action of extra heavy vehicle with low speed

    Institute of Scientific and Technical Information of China (English)

    刘波; 王有志; 胡朋; 袁泉

    2015-01-01

    To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.

  5. Coupling Analysis of Low-Speed Multiphase Flow and High-Frequency Electromagnetic Field in a Complex Pipeline Structure

    Directory of Open Access Journals (Sweden)

    Xiaokai Huo

    2014-01-01

    Full Text Available Accurate estimation of water content in an oil-water mixture is a key technology in oil exploration and production. Based on the principles of the microwave transmission line (MTL, the logging probe is an important water content measuring apparatus. However, the effects of mixed fluid flow on the measurement of electromagnetic field parameters are rarely considered. This study presents the coupling model for low-speed multiphase flow and high-frequency electromagnetic field in a complex pipeline structure. We derived the S-parameter equations for the stratified oil/water flow model. The corresponding relationship between the S-parameters and water holdup is established. Evident coupling effects of the fluid flow and the electromagnetic field are confirmed by comparing the calculated S-parameters for both stratified and homogeneous flow patterns. In addition, a multiple-solution problem is analyzed for the inversion of dielectric constant from the S-parameters. The most sensitive phase angle range is determined to improve the detection of variation in the dielectric constant. Suggestions are proposed based on the influence of the oil/water layer on measurement sensitivity to optimize the geometric parameters of a device structure. The method proposed elucidates how accuracy and sensitivity can be improved in water holdup measurements under high water content conditions.

  6. An Efficient Image Compressor for Charge Coupled Devices Camera

    Directory of Open Access Journals (Sweden)

    Jin Li

    2014-01-01

    Full Text Available Recently, the discrete wavelet transforms- (DWT- based compressor, such as JPEG2000 and CCSDS-IDC, is widely seen as the state of the art compression scheme for charge coupled devices (CCD camera. However, CCD images project on the DWT basis to produce a large number of large amplitude high-frequency coefficients because these images have a large number of complex texture and contour information, which are disadvantage for the later coding. In this paper, we proposed a low-complexity posttransform coupled with compressing sensing (PT-CS compression approach for remote sensing image. First, the DWT is applied to the remote sensing image. Then, a pair base posttransform is applied to the DWT coefficients. The pair base are DCT base and Hadamard base, which can be used on the high and low bit-rate, respectively. The best posttransform is selected by the lp-norm-based approach. The posttransform is considered as the sparse representation stage of CS. The posttransform coefficients are resampled by sensing measurement matrix. Experimental results on on-board CCD camera images show that the proposed approach significantly outperforms the CCSDS-IDC-based coder, and its performance is comparable to that of the JPEG2000 at low bit rate and it does not have the high excessive implementation complexity of JPEG2000.

  7. Test Data Report, Low-Speed Wind Tunnel Drag Test of a 2/5 Scale Lockheed AH-56 Cheyenne Door-Hinge Hub

    Science.gov (United States)

    2016-07-01

    SPECIAL REPORT RDMR-AD-16-03 TEST DATA REPORT, LOW-SPEED WIND TUNNEL DRAG TEST OF A 2/5 SCALE LOCKHEED AH-56 CHEYENNE DOOR-HINGE HUB Robert D...TYPE AND DATES COVERED Final 4. TITLE AND SUBTITLE Test Data Report, Low-Speed Wind Tunnel Drag Test of a 2/5 Scale Lockheed AH-56 Cheyenne...Research, Development and Engineering Center (AMRDEC) conducted a drag test of a non-rotating 2/5 scale Lockheed AH-56 Cheyenne main rotor hub in

  8. Subaru Prime Focus Camera -- Suprime-Cam --

    CERN Document Server

    Miyazaki, S; Sekiguchi, M; Okamura, S; Doi, M; Furusawa, H; Hamabe, M; Imi, K; Kimura, M; Nakata, F; Okada, N; Ouchi, M; Shimasaku, K; Yagi, M; Yasuda, N; Miyazaki, Satoshi; Komiyama, Yutaka; Sekiguchi, Maki; Okamura, Sadanori; Doi, Mamoru; Furusawa, Hisanori; Hamabe, Masaru; Imi, Katsumi; Kimura, Masahiki; Nakata, Fumiaki; Okada, Norio; Ouchi, Masami; Shimasaku, Kazuhiro; Yagi, Masafumi; Yasuda, Naoki

    2002-01-01

    We have built an 80 mega pixels (10240 X 8192) mosaic CCD camera, called Suprime-Cam, for the wide field prime focus of the 8.2 m Subaru telescope. Suprime-Cam covers a field of view 34 arcmin X 27 arcmin, a unique facility among the the 8 - 10 m class telescopes, with a resolution of 0.202 arcsec per pixel. The focal plane consists of ten high-resistivity 2kX4k CCDs developed by MIT Lincoln Laboratory and these are cooled by a large stirling cycle cooler. The CCD readout electronics are developed originally by our group (M-Front & Messia-III) and the system is designed scalable that allows multiple read-out of tens of CCDs. It takes 50 seconds to readout entire arrays. We have designed a filter exchange mechanism of jukebox type that can holds up to ten large filters (205 X 170 X 15 mm^3). The wide field corrector is basically a three-lens Wynne-type but has a new type of atmospheric dispersion corrector. The corrector provides flat focal plane and un-vignetted field of view of 30 arcmin in diameter. Ach...

  9. Upgrade of the SOFIA target acquisition and tracking cameras

    Science.gov (United States)

    Wolf, Jürgen; Wiedemann, Manuel; Pfüller, Enrico; Lachenmann, Michael; Hall, Helen J.; Röser, Hans-Peter

    2014-07-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) uses three visible range CCD cameras with different optics for target acquisition and tracking. The Wide Field Imager (WFI with 68mm f/2.0 optics) and the Fine Field Imager (FFI with 254mm f/2.8 optics) are mounted on the telescope front ring and are therefore exposed to stratospheric conditions in flight. The Focal Plane Imager (FPI) receives visible light from the 2.5m Cassegrain/Nasmyth telescope via a dichroic tertiary mirror and is mounted inside the pressurized aircraft cabin at typically +20°C. An upgrade of these three imagers is currently in progress. The new FPI was integrated in February 2013 and is operating as SOFIA's main tracking camera since then. The new FFI and WFI are planned to be integrated in summer of 2015. Andor iXonEM+ DU- 888 cameras will be used in all three imagers to significantly increase the sensitivity compared to the previous CCD sensors. This will allow for tracking on fainter stars, e.g. the new FPI can track on a 16mag star with an integration time of 2 sec. While the FPI uses a commercial off the shelf camera, the cameras for FFI and WFI are extensively modified to withstand the harsh stratospheric environment. The two front ring imagers will also receive new optics to improve the image quality and to provide a stable focus position throughout the temperature range that SOFIA operates in. In this paper we will report on the results of the new FPI and the status of the FFI/WFI upgrade work. This includes the selection and design of the new optics and the design and testing of a prototype camera for the stratosphere. We will also report on preparations to make the new FPI available for scientific measurements.

  10. Camera as Cultural Critique

    DEFF Research Database (Denmark)

    Suhr, Christian

    2015-01-01

    What does the use of cameras entail for the production of cultural critique in anthropology? Visual anthropological analysis and cultural critique starts at the very moment a camera is brought into the field or existing visual images are engaged. The framing, distances, and interactions between...... to establish analysis as a continued, iterative movement of transcultural dialogue and critique....

  11. Camera Operator and Videographer

    Science.gov (United States)

    Moore, Pam

    2007-01-01

    Television, video, and motion picture camera operators produce images that tell a story, inform or entertain an audience, or record an event. They use various cameras to shoot a wide range of material, including television series, news and sporting events, music videos, motion pictures, documentaries, and training sessions. Those who film or…

  12. Log-converting processor element for CCD linear imaging arrays.

    Science.gov (United States)

    Chang, S H; Boyd, J T

    1983-11-15

    A photosensor element suitable for incorporation into charge-coupled device (CCD) imaging arrays in which the charge injected into the CCD is proportional to the logarithm of incident light intensity is presented. The photosensor element consists of a photodiode directly coupled to a two-stage MOSFET common source amplifier. This element occupies an area of 25 x 100 microm and is arranged so that it could be incorporated into a linear CCD imaging array having a period of 25 microm. A logarithmic response is measured over a 68.6-dB range of incident light intensity with a sensitivity of 55 mV/decade of light intensity.

  13. A new, accurate and easy to implement camera and video projector model.

    Science.gov (United States)

    Hoppe, Harald; Däuber, Sascha; Kübler, Carsten; Raczkowsky, Jörg; Wörn, Heinz

    2002-01-01

    In 2000, the Institute for Process Control and Robotics/Universität Karlsruhe (TH) has developed a prototype system for projector based augmented reality consisting of a state-of-the-art PC, two CCD cameras and a video projector which is used for registration and projection of surgical planning data. Tracking, registration as well as projection require an accurate calibration process for cameras and video projectors. We have developed a new, flexible, plain and easy to implement model, which can both be used for calibration of cameras and video projectors.

  14. Three-dimensional temperature field measurement of flame using a single light field camera.

    Science.gov (United States)

    Sun, Jun; Xu, Chuanlong; Zhang, Biao; Hossain, Md Moinul; Wang, Shimin; Qi, Hong; Tan, Heping

    2016-01-25

    Compared with conventional camera, the light field camera takes the advantage of being capable of recording the direction and intensity information of each ray projected onto the CCD (charge couple device) sensor simultaneously. In this paper, a novel method is proposed for reconstructing three-dimensional (3-D) temperature field of a flame based on a single light field camera. A radiative imaging of a single light field camera is also modeled for the flame. In this model, the principal ray represents the beam projected onto the pixel of the CCD sensor. The radiation direction of the ray from the flame outside the camera is obtained according to thin lens equation based on geometrical optics. The intensities of the principal rays recorded by the pixels on the CCD sensor are mathematically modeled based on radiative transfer equation. The temperature distribution of the flame is then reconstructed by solving the mathematical model through the use of least square QR-factorization algorithm (LSQR). The numerical simulations and experiments are carried out to investigate the validity of the proposed method. The results presented in this study show that the proposed method is capable of reconstructing the 3-D temperature field of a flame.

  15. 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....

  16. Dry imaging cameras

    Directory of Open Access Journals (Sweden)

    I K Indrajit

    2011-01-01

    Full Text Available Dry imaging cameras are important hard copy devices in radiology. Using dry imaging camera, multiformat images of digital modalities in radiology are created from a sealed unit of unexposed films. The functioning of a modern dry camera, involves a blend of concurrent processes, in areas of diverse sciences like computers, mechanics, thermal, optics, electricity and radiography. Broadly, hard copy devices are classified as laser and non laser based technology. When compared with the working knowledge and technical awareness of different modalities in radiology, the understanding of a dry imaging camera is often superficial and neglected. To fill this void, this article outlines the key features of a modern dry camera and its important issues that impact radiology workflow.

  17. Enzymatic study on AtCCD4 and AtCCD7 and their potential to form acyclic regulatory metabolites

    KAUST Repository

    Bruno, Mark

    2016-09-29

    The Arabidopsis carotenoid cleavage dioxygenase 4 (AtCCD4) is a negative regulator of the carotenoid content of seeds and has recently been suggested as a candidate for the generation of retrograde signals that are thought to derive from the cleavage of poly-cis-configured carotene desaturation intermediates. In this work, we investigated the activity of AtCCD4 in vitro and used dynamic modeling to determine its substrate preference. Our results document strict regional specificity for cleavage at the C9–C10 double bond in carotenoids and apocarotenoids, with preference for carotenoid substrates and an obstructing effect on hydroxyl functions, and demonstrate the specificity for all-trans-configured carotenes and xanthophylls. AtCCD4 cleaved substrates with at least one ionone ring and did not convert acyclic carotene desaturation intermediates, independent of their isomeric states. These results do not support a direct involvement of AtCCD4 in generating the supposed regulatory metabolites. In contrast, the strigolactone biosynthetic enzyme AtCCD7 converted 9-cis-configured acyclic carotenes, such as 9-cis-ζ-carotene, 9\\'-cis-neurosporene, and 9-cis-lycopene, yielding 9-cis-configured products and indicating that AtCCD7, rather than AtCCD4, is the candidate for forming acyclic retrograde signals.

  18. A New Serial-direction Trail Effect in CCD Images of the Lunar-based Ultraviolet Telescope

    Science.gov (United States)

    Wu, C.; Deng, J. S.; Guyonnet, A.; Antilogus, P.; Cao, L.; Cai, H. B.; Meng, X. M.; Han, X. H.; Qiu, Y. L.; Wang, J.; Wang, S.; Wei, J. Y.; Xin, L. P.; Li, G. W.

    2016-10-01

    Unexpected trails have been seen subsequent to relative bright sources in astronomical images taken with the CCD camera of the Lunar-based Ultraviolet Telescope (LUT) since its first light on the Moon’s surface. The trails can only be found in the serial-direction of CCD readout, differing themselves from image trails of radiation-damaged space-borne CCDs, which usually appear in the parallel-readout direction. After analyzing the same trail defects following warm pixels (WPs) in dark frames, we found that the relative intensity profile of the LUT CCD trails can be expressed as an exponential function of the distance i (in number of pixels) of the trailing pixel to the original source (or WP), i.e., {\\mathtt{\\exp }}(α {\\mathtt{i}}+β ). The parameters α and β seem to be independent of the CCD temperature, intensity of the source (or WP), and its position in the CCD frame. The main trail characteristics show evolution occurring at an increase rate of ˜(7.3 ± 3.6) × 10-4 in the first two operation years. The trails affect the consistency of the profiles of different brightness sources, which make smaller aperture photometry have larger extra systematic error. The astrometric uncertainty caused by the trails is too small to be acceptable based on LUT requirements for astrometry accuracy. Based on the empirical profile model, a correction method has been developed for LUT images that works well for restoring the fluxes of astronomical sources that are lost in trailing pixels.

  19. Prediction, postdiction, and perceptual length contraction: a Bayesian low-speed prior captures the cutaneous rabbit and related illusions

    Directory of Open Access Journals (Sweden)

    Daniel eGoldreich

    2013-05-01

    Full Text Available Illusions provide a window into the brain’s perceptual strategies. In certain illusions, an ostensibly task-irrelevant variable influences perception. For example, in touch as in audition and vision, the perceived distance between successive punctate stimuli reflects not only the actual distance but curiously the inter-stimulus time. Stimuli presented at different positions in rapid succession are drawn perceptually towards one another. This effect manifests in several illusions, among them the startling cutaneous rabbit, in which taps delivered to as few as two skin positions appear to hop progressively from one position to the next, landing in the process on intervening areas that were never stimulated. Here we provide an accessible step-by-step exposition of a Bayesian perceptual model that replicates the rabbit and related illusions. The Bayesian observer optimally joins uncertain estimates of spatial location with the expectation that stimuli tend to move slowly. We speculate that this expectation – a Bayesian prior – represents the statistics of naturally occurring stimuli, learned by humans through sensory experience. In its simplest form, the model contains a single free parameter, tau: a time constant for space perception. We show that the Bayesian observer incorporates both pre- and post-dictive inference. Directed spatial attention affects the prediction-postdiction balance, shifting the model’s percept towards the attended location, as observed experimentally in humans. Applying the model to the perception of multi-tap sequences, we show that the low-speed prior fits perception better than an alternative, low-acceleration prior. We discuss the applicability of our model to related tactile, visual, and auditory illusions. To facilitate future model-driven experimental studies, we present a convenient freeware computer program that implements the Bayesian observer; we invite investigators to use this program to create their own

  20. Riding performance on a conventional bicycle and a pedelec in low speed exercises : objective and subjective evaluation of middle-aged and older persons.

    NARCIS (Netherlands)

    Kovácsová, M. Winter, J.C.F. de Schwab, A.L. Christoph, M. Twisk, D.A.M. & Hagenzieker, M.P.

    2016-01-01

    This study investigated cycling performance of middle-aged (30–45 years old; n = 30) versus older (65+ years; n = 31) participants during low-speed tasks for which stabilization skills are known to be important. Additionally, participants’ self-ratings of their cycling skills and performance were as

  1. 78 FR 16358 - Safety Advisory 2013-02; Low-Speed, Wheel-Climb Derailments of Passenger Equipment With “Stiff...

    Science.gov (United States)

    2013-03-14

    ... the full range of component tolerances (e.g., spring heights) and maintenance limits (e.g., wheel wear... determined. Additionally, FRA understands that softer springs, which may be selected to provide better wheel... Federal Railroad Administration Safety Advisory 2013-02; Low-Speed, Wheel-Climb Derailments of...

  2. Atmospheric correction of CBERS CCD images with MODIS data

    Institute of Scientific and Technical Information of China (English)

    LI; Junsheng; ZHANG; Bing; CHEN; Zhengchao; SHEN; Qian

    2006-01-01

    China Brazil Earth Resource Satellite (CBERS) CCD images have much potential for inland water environmental monitoring. However, their atmospheric accuracy correction can affect their quantitative applications. This paper contains an atmospheric correction algorithm for CBERS CCD images with MODIS data from the same day, the use of which improves the atmospheric correction algorithm of ocean color remote sensing developed by Gordon (1993, 1994) and makes it applicable to inland waters. The improved algorithm retrieves atmospheric parameters from MODIS data and uses them to perform the atmospheric correction of CBERS CCD images. Experimental results show that the atmospheric correction algorithm of CBERS CCD images assisted by MODIS data is reliable. Furthermore, MODIS data can be freely obtained on a daily basis, making the algorithm developed in this paper useful for environmental monitoring of inland waters.

  3. Correlation and image compression for limited-bandwidth CCD.

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Douglas G.

    2005-07-01

    As radars move to Unmanned Aerial Vehicles with limited-bandwidth data downlinks, the amount of data stored and transmitted with each image becomes more significant. This document gives the results of a study to determine the effect of lossy compression in the image magnitude and phase on Coherent Change Detection (CCD). We examine 44 lossy compression types, plus lossless zlib compression, and test each compression method with over 600 CCD image pairs. We also derive theoretical predictions for the correlation for most of these compression schemes, which compare favorably with the experimental results. We recommend image transmission formats for limited-bandwidth programs having various requirements for CCD, including programs which cannot allow performance degradation and those which have stricter bandwidth requirements at the expense of CCD performance.

  4. Micrometer and CCD measurements of double stars (Series 51

    Directory of Open Access Journals (Sweden)

    Popović G.M.

    1998-01-01

    Full Text Available 36 micrometric measurements of 20 double or multiple systems carried out with the Zeiss 65/1055 cm Refractor of Belgrade Observatory are communicated. Also 35 CCD measurements of 15 double or multiple systems are included.

  5. Target Image Matching Algorithm Based on Binocular CCD Ranging

    Directory of Open Access Journals (Sweden)

    Dongming Li

    2014-01-01

    Full Text Available This paper proposed target image in a subpixel level matching algorithm for binocular CCD ranging, which is based on the principle of binocular CCD ranging. In the paper, firstly, we introduced the ranging principle of the binocular ranging system and deduced a binocular parallax formula. Secondly, we deduced the algorithm which was named improved cross-correlation matching algorithm and cubic surface fitting algorithm for target images matched, and it could achieve a subpixel level matching for binocular CCD ranging images. Lastly, through experiment we have analyzed and verified the actual CCD ranging images, then analyzed the errors of the experimental results and corrected the formula of calculating system errors. Experimental results showed that the actual measurement accuracy of a target within 3 km was higher than 0.52%, which meet the accuracy requirements of the high precision binocular ranging.

  6. Experiments on the use of CCD's to detect photoelectron images

    Science.gov (United States)

    Choisser, J. P.

    1975-01-01

    Image tube design and processing requirements for building an ICCD are discussed. Work is under way at EVC for building an ICCD using the Fairchild CCD 201 (100 x 100) array, and progress will be reported. Demountable tests have been made, exposing parts of a CCD 201 to 15 kilovolt electrons over five radiation levels from approximately 10 to 1 million rads. Other tubes built by EVC over the last few years which successfully use semiconductors to detect photoelectrons will be described briefly.

  7. Collection and processing data for high quality CCD images.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2007-03-01

    Coherent Change Detection (CCD) with Synthetic Aperture Radar (SAR) images is a technique whereby very subtle temporal changes can be discerned in a target scene. However, optimal performance requires carefully matching data collection geometries and adjusting the processing to compensate for imprecision in the collection geometries. Tolerances in the precision of the data collection are discussed, and anecdotal advice is presented for optimum CCD performance. Processing considerations are also discussed.

  8. Research of aerial camera focal pane micro-displacement measurement system based on Michelson interferometer

    Science.gov (United States)

    Wang, Shu-juan; Zhao, Yu-liang; Li, Shu-jun

    2014-09-01

    The aerial camera focal plane in the correct position is critical to the imaging quality. In order to adjust the aerial camera focal plane displacement caused in the process of maintenance, a new micro-displacement measuring system of aerial camera focal plane in view of the Michelson interferometer has been designed in this paper, which is based on the phase modulation principle, and uses the interference effect to realize the focal plane of the micro-displacement measurement. The system takes He-Ne laser as the light source, uses the Michelson interference mechanism to produce interference fringes, changes with the motion of the aerial camera focal plane interference fringes periodically, and records the periodicity of the change of the interference fringes to obtain the aerial camera plane displacement; Taking linear CCD and its driving system as the interference fringes picking up tool, relying on the frequency conversion and differentiating system, the system determines the moving direction of the focal plane. After data collecting, filtering, amplifying, threshold comparing, counting, CCD video signals of the interference fringes are sent into the computer processed automatically, and output the focal plane micro displacement results. As a result, the focal plane micro displacement can be measured automatically by this system. This system uses linear CCD as the interference fringes picking up tool, greatly improving the counting accuracy and eliminated the artificial counting error almost, improving the measurement accuracy of the system. The results of the experiments demonstrate that: the aerial camera focal plane displacement measurement accuracy is 0.2nm. While tests in the laboratory and flight show that aerial camera focal plane positioning is accurate and can satisfy the requirement of the aerial camera imaging.

  9. Development of photoelectric balanced car based on the linear CCD sensor

    Directory of Open Access Journals (Sweden)

    Wang Feng

    2016-01-01

    Full Text Available The smart car is designed based on Freescale’s MC9S12XS128 and a linear CCD camera. The linear CCD collects the road information and sends it to MCU through the operational amplifier. The PID control algorithm, the proportional–integral–derivative control algorithm, is adopted synthetically to control the smart car. First, the smart car’s inclination and angular velocity are detect through the accelerometers and gyro sensors, then the PD control algorithm, the proportional–derivative control algorithm, is employed to make the smart car have the ability of two-wheeled self-balancing. Second, the speed of wheel obtained by the encoder is fed back to the MCU by way of pulse signal, then the PI control algorithm, the proportional–integral control algorithm, is employed to make the speed of smart car reach the set point in the shortest possible time and stabilize at the set point. Finally, the PD control algorithm is used to regulate the smart car’s turning angle to make the smart car respond quickly while the smart car is passing the curve path. The smart car can realize the self-balancing control of two wheels and track automatically the black and while lines to march.

  10. First observations from a CCD all-sky spectrograph at Barentsburg (Spitsbergen

    Directory of Open Access Journals (Sweden)

    S. A. Chernouss

    2008-05-01

    Full Text Available A digital CCD all-sky spectrograph was made by the Polar Geophysical Institute (PGI to support IPY activity in auroral research. The device was tested at the Barentsburg observatory of PGI during the winter season of 2005–2006. The spectrograph is based on a cooled CCD and a transmission grating. The main features of this spectrograph are: a wide field of view (~180°, a wide spectral range (380–740 nm, a spectral resolution of 0.6 nm, a background level of about 100 R at 1-min exposure time. Several thousand spectra of nightglow and aurora were recorded during the observation season. It was possible to register both the strong auroral emissions, as well as weak ones. Spectra of aurora, including nitrogen and oxygen molecular and atomic emissions, as well as OH emissions of the nightglow are shown. A comparison has been conducted of auroral spectra obtained by the film all-sky spectral camera C-180-S at Spitsbergen during IGY, with spectra obtained at Barentsburg during the last winter season. The relationship between the red (630.0 nm and green (557.7 nm auroral emissions shows that the green emission is dominant near the minimum of the solar cycle activity (2005–2006. The opposite situation is observed during 1958–1959, with a maximum solar cycle activity.

  11. A new method of CCD dark current correction via extracting the dark information from scientific images

    CERN Document Server

    Ma, Bin; Hu, Yi; Liu, Qiang; Wang, Lifan; Wei, Peng

    2014-01-01

    We have developed a new method to correct dark current at relatively high temperatures for Charge-Coupled Device (CCD) images when dark frames cannot be obtained on the telescope. For images taken with the Antarctic Survey Telescopes (AST3) in 2012, due to the low cooling efficiency, the median CCD temperature was -46$^\\circ$C, resulting in a high dark current level of about 3$e^-$/pix/sec, even comparable to the sky brightness (10$e^-$/pix/sec). If not corrected, the nonuniformity of the dark current could even overweight the photon noise of the sky background. However, dark frames could not be obtained during the observing season because the camera was operated in frame-transfer mode without a shutter, and the telescope was unattended in winter. Here we present an alternative, but simple and effective method to derive the dark current frame from the scientific images. Then we can scale this dark frame to the temperature at which the scientific images were taken, and apply the dark frame corrections to the s...

  12. VizieR Online Data Catalog: CCD UBV photometry of close visual doubles (Nakos+ 1997)

    Science.gov (United States)

    Nakos, T.; Sinachopoulos, D.; van Dessel, E.

    1996-11-01

    We present V magnitudes, (B-V) and (U-B) colours of close visual double star components, and their differences as well as separations and position angles of 40 visual double stars. The common properties of the members of this sample are the small angular separation ρ, which is less than 7", and the common spectral type of the primaries, which are of G-type. The observations made with the Bessel U, B and V filters, while the astrometry was performed in the V filter only. For the observations, the CCD camera attached to the Cassegrain focus of the 90 cm Dutch telescope, at La Silla, Chile, had been used. From the analysis of the data we concluded that from the sample of the fourty double stars observed seven proved to be physical pairs, while the rest must have common origin components. (3 data files).

  13. Soft X-ray response of a CCD with a grating spectrometer

    CERN Document Server

    Shouho, M; Katayama, H; Kohmura, T; Tsunemi, H; Kitamoto, S; Hayashida, K; Miyata, E; Hashimotodani, K; Yoshita, K; Koyama, K; Ricker, G; Bautz, M W; Foster, R; Kissel, S

    1999-01-01

    We calibrate the X-ray imaging spectrometers, which are CCD cameras installed on the ASTRO-E satellite, by using dispersed continuous soft X-rays from a grating spectrometer. We obtained the signal-pulse height and energy-resolution as a function of X-ray energies continuously. However, the wings of the line spread function of the grating distorts the center of the signal-pulse height derived by a simple analysis. An estimation of this distortion is presented. We also describe two methods of extracting the pure signal-pulse-height distribution from the data using the spectrometer. A brief description of the low-energy tail is presented.

  14. White light interferometer with color CCD for 3D-surface profiling of microsystems

    Science.gov (United States)

    Upputuri, Paul K.; Pramanik, Manojit; Nandigana, Krishna M.; Kothiyal, Mahendra P.

    2015-03-01

    White light interferometry (WLI) is a state-of-the-art technique for high resolution full-filed 3-D surface profiling of Microsystems. However, the WLI is rather slow, because the number of frames to be recorded and evaluated is large compared to the single wavelength phase shifting interferometry. In this paper, we combine white light interferometer with a single-chip color CCD camera which makes the measurement faster, simpler, and cost-effective. The red-bluegreen (RGB) color interferogram stored in a computer is then decomposed into its individual components and corresponding phase maps for red, green, and blue components are calculated independently. The usefulness of the technique is demonstrated on reflective micro-scale-samples.

  15. Photon counting imaging and centroiding with an electron-bombarded CCD using single molecule localisation software

    Science.gov (United States)

    Hirvonen, Liisa M.; Barber, Matthew J.; Suhling, Klaus

    2016-06-01

    Photon event centroiding in photon counting imaging and single-molecule localisation in super-resolution fluorescence microscopy share many traits. Although photon event centroiding has traditionally been performed with simple single-iteration algorithms, we recently reported that iterative fitting algorithms originally developed for single-molecule localisation fluorescence microscopy work very well when applied to centroiding photon events imaged with an MCP-intensified CMOS camera. Here, we have applied these algorithms for centroiding of photon events from an electron-bombarded CCD (EBCCD). We find that centroiding algorithms based on iterative fitting of the photon events yield excellent results and allow fitting of overlapping photon events, a feature not reported before and an important aspect to facilitate an increased count rate and shorter acquisition times.

  16. Imaging the Moon II: Webcam CCD observations & analysis (a two week lab for non-majors)

    CERN Document Server

    Sato, Takashi

    2013-01-01

    Presented is a successful two week lab involving real sky observations of the Moon in which students make telescopic observations and analyze their own images. Originally developed around the 35 mm film camera as a common household object adapted for astronomical work, the lab transitioned to use the webcam as film photography evolved into an obscure specialty technology and increasing numbers of students had little familiarity with it. The printed circuit board with the CCD is harvested from a retail webcam and affixed to a tube to mount on a telescope in place of an eyepiece. Image frames are compiled to form a lunar mosaic and crater sizes are measured. Students also work through the logistical steps of telescope time assignment and scheduling, keeping to schedule and working with uncertainties of weather, in ways paralleling research observations. Because there is no need for a campus observatory, this lab can be replicated at a wide variety of institutions.

  17. Do Speed Cameras Reduce Collisions?

    OpenAIRE

    Skubic, Jeffrey; Johnson, Steven B.; Salvino, Chris; Vanhoy, Steven; Hu, Chengcheng

    2013-01-01

    We investigated the effects of speed cameras along a 26 mile segment in metropolitan Phoenix, Arizona. Motor vehicle collisions were retrospectively identified according to three time periods – before cameras were placed, while cameras were in place and after cameras were removed. A 14 mile segment in the same area without cameras was used for control purposes. Five cofounding variables were eliminated. In this study, the placement or removal of interstate highway speed cameras did not indepe...

  18. Do speed cameras reduce collisions?

    Science.gov (United States)

    Skubic, Jeffrey; Johnson, Steven B; Salvino, Chris; Vanhoy, Steven; Hu, Chengcheng

    2013-01-01

    We investigated the effects of speed cameras along a 26 mile segment in metropolitan Phoenix, Arizona. Motor vehicle collisions were retrospectively identified according to three time periods - before cameras were placed, while cameras were in place and after cameras were removed. A 14 mile segment in the same area without cameras was used for control purposes. Five cofounding variables were eliminated. In this study, the placement or removal of interstate highway speed cameras did not independently affect the incidence of motor vehicle collisions.

  19. TARGETLESS CAMERA CALIBRATION

    Directory of Open Access Journals (Sweden)

    L. Barazzetti

    2012-09-01

    Full Text Available In photogrammetry a camera is considered calibrated if its interior orientation parameters are known. These encompass the principal distance, the principal point position and some Additional Parameters used to model possible systematic errors. The current state of the art for automated camera calibration relies on the use of coded targets to accurately determine the image correspondences. This paper presents a new methodology for the efficient and rigorous photogrammetric calibration of digital cameras which does not require any longer the use of targets. A set of images depicting a scene with a good texture are sufficient for the extraction of natural corresponding image points. These are automatically matched with feature-based approaches and robust estimation techniques. The successive photogrammetric bundle adjustment retrieves the unknown camera parameters and their theoretical accuracies. Examples, considerations and comparisons with real data and different case studies are illustrated to show the potentialities of the proposed methodology.

  20. TOUCHSCREEN USING WEB CAMERA

    Directory of Open Access Journals (Sweden)

    Kuntal B. Adak

    2015-10-01

    Full Text Available In this paper we present a web camera based touchscreen system which uses a simple technique to detect and locate finger. We have used a camera and regular screen to achieve our goal. By capturing the video and calculating position of finger on the screen, we can determine the touch position and do some function on that location. Our method is very easy and simple to implement. Even our system requirement is less expensive compare to other techniques.

  1. The Circular Camera Movement

    DEFF Research Database (Denmark)

    Hansen, Lennard Højbjerg

    2014-01-01

    It has been an accepted precept in film theory that specific stylistic features do not express specific content. Nevertheless, it is possible to find many examples in the history of film in which stylistic features do express specific content: for instance, the circular camera movement is used...... such as the circular camera movement. Keywords: embodied perception, embodied style, explicit narration, interpretation, style pattern, television style...

  2. Segment Based Camera Calibration

    Institute of Scientific and Technical Information of China (English)

    马颂德; 魏国庆; 等

    1993-01-01

    The basic idea of calibrating a camera system in previous approaches is to determine camera parmeters by using a set of known 3D points as calibration reference.In this paper,we present a method of camera calibration in whih camera parameters are determined by a set of 3D lines.A set of constraints is derived on camea parameters in terms of perspective line mapping.Form these constraints,the same perspective transformation matrix as that for point mapping can be computed linearly.The minimum number of calibration lines is 6.This result generalizes that of Liu,Huang and Faugeras[12] for camera location determination in which at least 8 line correspondences are required for linear computation of camera location.Since line segments in an image can be located easily and more accurately than points,the use of lines as calibration reference tends to ease the computation in inage preprocessing and to improve calibration accuracy.Experimental results on the calibration along with stereo reconstruction are reported.

  3. Meteor Film Recording with Digital Film Cameras with large CMOS Sensors

    Science.gov (United States)

    Slansky, P. C.

    2016-12-01

    In this article the author combines his professional know-how about cameras for film and television production with his amateur astronomy activities. Professional digital film cameras with high sensitivity are still quite rare in astronomy. One reason for this may be their costs of up to 20 000 and more (camera body only). In the interim, however,consumer photo cameras with film mode and very high sensitivity have come to the market for about 2 000 EUR. In addition, ultra-high sensitive professional film cameras, that are very interesting for meteor observation, have been introduced to the market. The particular benefits of digital film cameras with large CMOS sensors, including photo cameras with film recording function, for meteor recording are presented by three examples: a 2014 Camelopardalid, shot with a Canon EOS C 300, an exploding 2014 Aurigid, shot with a Sony alpha7S, and the 2016 Perseids, shot with a Canon ME20F-SH. All three cameras use large CMOS sensors; "large" meaning Super-35 mm, the classic 35 mm film format (24x13.5 mm, similar to APS-C size), or full format (36x24 mm), the classic 135 photo camera format. Comparisons are made to the widely used cameras with small CCD sensors, such as Mintron or Watec; "small" meaning 12" (6.4x4.8 mm) or less. Additionally, special photographic image processing of meteor film recordings is discussed.

  4. An Advanced Atmospheric Dispersion Corrector: The Magellan Visible AO Camera

    OpenAIRE

    Kopon, Derek; Close, Laird M.; Gasho, Victor

    2010-01-01

    In addition to the BLINC/MIRAC IR science instruments, the Magellan adaptive secondary AO system will have an EEV CCD47 that can be used both for visible AO science and as a wide-field acquisition camera. The effects of atmospheric dispersion on the elongation of the diffraction limited Magellan adaptive optics system point spread function (PSF) are significant in the near IR. This elongation becomes particularly egregious at visible wavelengths, culminating in a PSF that is 2000\\{mu}m long i...

  5. High-speed multicolor photometry with CMOS cameras

    CERN Document Server

    Pokhvala, S M; Reshetnyk, V M

    2012-01-01

    We present the results of testing the commercial digital camera Nikon D90 with a CMOS sensor for high-speed photometry with a small telescope Celestron 11" on Peak Terskol. CMOS sensor allows to perform photometry in 3 filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR color system of CMOS sensors is close to the Johnson BVR system. The results of testing show that we can measure the stars up to V $\\simeq$ 14 with the precision of 0.01 mag. Stars up to magnitude V $\\sim$ 10 can shoot at 24 frames per second in the video mode.

  6. SIMULTANEOUS RECORDING OF FRINGE PATTERNS WITH ONE CAMERA

    Institute of Scientific and Technical Information of China (English)

    SU Fei; DAI Fulong; CHIAN Kerm Sin; YI Sung

    2004-01-01

    A novel method to separate and simultaneously record the Moiré interferometry fringe patterns of three deformation fields with only one CCD camera is developed; details of its operation principle, key points and error analysis are presented. With this technique, the deformation in U, V and W fields can be measured simultaneously, so dynamic test with comprehensive information can be performed. The advantage of this technique over other similar techniques lies in its simplicity, easy implementation and low cost. An application of this technique is given to show its feasibility. Technical problems that may be caused with this technique are also analyzed.

  7. Real-time auto-focusing technique using centroid method for space camera

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A real-time auto-focusing system with auto-collimation method is introduced, which is used in autodetecting the focus of the space camera with long focus. Auto-focusing is the key technique to ensure high quality in space imaging. It can measure and compensate the defocus caused by the change of temperature and air pressure etc. in space. To solve the problem of auto-focusing with auto-collimation method of the camera whose axis is perpendicular to the ground, it is designed that two small caliber pentagonal prisms are placed in the area of aperture suitable to the camera's relative aperture based on the theory of auto-focusing with auto-collimation, which can replace the big caliber plane reflector used in other cameras. Using the characteristic of pentagonal prism refracting light vertically, the target slit is imaged in CCD through the two-separated lens. It transforms the detecting of the axial defocusing quantity to the landscape orientation measurement of the faculae's position in the direction of CCD pixels. The defocusing quantity is obtained by measuring the opposite position of the two faculae on the CCD. The Centroid method is adopted to measure the position of the auto-collimation faculae. The arithmetic error is analyzed especially, and the causation is given. Experiments show that this real-time auto-focusing system using centroid method is reliable and the focusing precision can reach ±0.01 mm.

  8. Uncooled radiometric camera performance

    Science.gov (United States)

    Meyer, Bill; Hoelter, T.

    1998-07-01

    Thermal imaging equipment utilizing microbolometer detectors operating at room temperature has found widespread acceptance in both military and commercial applications. Uncooled camera products are becoming effective solutions to applications currently using traditional, photonic infrared sensors. The reduced power consumption and decreased mechanical complexity offered by uncooled cameras have realized highly reliable, low-cost, hand-held instruments. Initially these instruments displayed only relative temperature differences which limited their usefulness in applications such as Thermography. Radiometrically calibrated microbolometer instruments are now available. The ExplorIR Thermography camera leverages the technology developed for Raytheon Systems Company's first production microbolometer imaging camera, the Sentinel. The ExplorIR camera has a demonstrated temperature measurement accuracy of 4 degrees Celsius or 4% of the measured value (whichever is greater) over scene temperatures ranges of minus 20 degrees Celsius to 300 degrees Celsius (minus 20 degrees Celsius to 900 degrees Celsius for extended range models) and camera environmental temperatures of minus 10 degrees Celsius to 40 degrees Celsius. Direct temperature measurement with high resolution video imaging creates some unique challenges when using uncooled detectors. A temperature controlled, field-of-view limiting aperture (cold shield) is not typically included in the small volume dewars used for uncooled detector packages. The lack of a field-of-view shield allows a significant amount of extraneous radiation from the dewar walls and lens body to affect the sensor operation. In addition, the transmission of the Germanium lens elements is a function of ambient temperature. The ExplorIR camera design compensates for these environmental effects while maintaining the accuracy and dynamic range required by today's predictive maintenance and condition monitoring markets.

  9. Development of SED Camera for Quasars in Early Universe (SQUEAN)

    CERN Document Server

    Kim, Sanghyuk; Lee, Hye-In; Park, Woojin; Ji, Tae-Geun; Hyun, Minhee; Choi, Changsu; Im, Myungshin; Pak, Soojong

    2016-01-01

    We describe the characteristics and performance of a camera system, Spectral energy distribution Camera for Quasars in Early Universe (SQUEAN). It was developed to measure SEDs of high redshift quasar candidates (z $\\gtrsim$ 5) and other targets, e.g., young stellar objects, supernovae, and gamma-ray bursts, and to trace the time variability of SEDs of objects such as active galactic nuclei (AGNs). SQUEAN consists of an on-axis focal plane camera module, an auto-guiding system, and mechanical supporting structures. The science camera module is composed of a focal reducer, a customizable filter wheel, and a CCD camera on the focal plane. The filter wheel uses filter cartridges that can house filters with different shapes and sizes, enabling the filter wheel to hold twenty filters of 50 mm $\\times$ 50 mm size, ten filters of 86 mm $\\times$ 86 mm size, or many other combinations. The initial filter mask was applied to calibrate the filter wheel with high accuracy and we verified that the filter position is repea...

  10. Development of SED Camera for Quasars in Early Universe (SQUEAN)

    Science.gov (United States)

    Kim, Sanghyuk; Jeon, Yiseul; Lee, Hye-In; Park, Woojin; Ji, Tae-Geun; Hyun, Minhee; Choi, Changsu; Im, Myungshin; Pak, Soojong

    2016-11-01

    We describe the characteristics and performance of a camera system, Spectral energy distribution Camera for Quasars in Early Universe (SQUEAN). It was developed to measure SEDs of high-redshift quasar candidates (z ≳ 5) and other targets, e.g., young stellar objects, supernovae, and gamma-ray bursts, and to trace the time variability of SEDs of objects such as active galactic nuclei (AGNs). SQUEAN consists of an on-axis focal plane camera module, an autoguiding system, and mechanical supporting structures. The science camera module is composed of a focal reducer, a customizable filter wheel, and a CCD camera on the focal plane. The filter wheel uses filter cartridges that can house filters with different shapes and sizes, enabling the filter wheel to hold 20 filters of 50 mm × 50 mm size, 10 filters of 86 mm × 86 mm size, or many other combinations. The initial filter mask was applied to calibrate the filter wheel with high accuracy, and we verified that the filter position is repeatable at much less than one pixel accuracy. We installed and tested 50 nm medium bandwidth filters of 600–1050 nm and other filters at the commissioning observation in 2015 February. We found that SQUEAN can reach limiting magnitudes of 23.3–25.3 AB mag at 5σ in a one-hour total integration time.

  11. A highly reliable and budget-friendly Peltier-cooled camera for biological fluorescence imaging microscopy.

    Science.gov (United States)

    Jolling, Koen; Vandeven, Martin; Van den Eynden, Jimmy; Ameloot, Marcel; Van Kerkhove, Emmy

    2007-12-01

    The SAC8.5, a low-cost Peltier-cooled black and white 8-bit CCD camera for astronomy, was evaluated for its use in imaging microscopy. Two camera-microscope configurations were used: an epifluorescence microscope (Nikon Eclipse TE2000-U) and a bottom port laser scanning confocal microscope system (Zeiss LSCM 510 META). Main advantages of the CCD camera over the currently used photomultiplier detection in the scanning setup are fast image capturing, stable background, an improved signal-to-noise ratio and good linearity. Based on DAPI-labelled Chinese Hamster Ovarian cells, the signal-to-noise ratio was estimated to be 4 times higher with respect to the currently used confocal photomultiplier detector. A linear relationship between the fluorescence signal and the FITC-inulin concentrations ranging from 0.05 to 1.8 mg mL(-1) could be established. With the SAC8.5 CCD camera and using DAPI, calcein-AM and propidium iodide we could also distinguish between viable, apoptotic and necrotic cells: exposure to CdCl(2) caused necrosis in A6 cells. Additional examples include the observation of wire-like mitochondrial networks in Mito Tracker Green-loaded Madin-Darby canine kidney cells. Furthermore, it is straightforward to interface the SAC8.5 with automated shutters to prevent rapid fluorophore photobleaching via easy to use astrovideo software. In this study, we demonstrate that the SAC8.5 black and white CCD camera is an easy-to-implement and cost-conscious addition to quantitative fluorescence microfluorimetry on living tissues and is suitable for teaching laboratories.

  12. CAOS-CMOS camera.

    Science.gov (United States)

    Riza, Nabeel A; La Torre, Juan Pablo; Amin, M Junaid

    2016-06-13

    Proposed and experimentally demonstrated is the CAOS-CMOS camera design that combines the coded access optical sensor (CAOS) imager platform with the CMOS multi-pixel optical sensor. The unique CAOS-CMOS camera engages the classic CMOS sensor light staring mode with the time-frequency-space agile pixel CAOS imager mode within one programmable optical unit to realize a high dynamic range imager for extreme light contrast conditions. The experimentally demonstrated CAOS-CMOS camera is built using a digital micromirror device, a silicon point-photo-detector with a variable gain amplifier, and a silicon CMOS sensor with a maximum rated 51.3 dB dynamic range. White light imaging of three different brightness simultaneously viewed targets, that is not possible by the CMOS sensor, is achieved by the CAOS-CMOS camera demonstrating an 82.06 dB dynamic range. Applications for the camera include industrial machine vision, welding, laser analysis, automotive, night vision, surveillance and multispectral military systems.

  13. Applicability of linearized-theory attached-flow methods to design and analysis of flap systems at low speeds for thin swept wings with sharp leading edges

    Science.gov (United States)

    Carlson, Harry W.; Darden, Christine M.

    1987-01-01

    Low-speed experimental force and data on a series of thin swept wings with sharp leading edges and leading and trailing-edge flaps are compared with predictions made using a linearized-theory method which includes estimates of vortex forces. These comparisons were made to assess the effectiveness of linearized-theory methods for use in the design and analysis of flap systems in subsonic flow. Results demonstrate that linearized-theory, attached-flow methods (with approximate representation of vortex forces) can form the basis of a rational system for flap design and analysis. Even attached-flow methods that do not take vortex forces into account can be used for the selection of optimized flap-system geometry, but design-point performance levels tend to be underestimated unless vortex forces are included. Illustrative examples of the use of these methods in the design of efficient low-speed flap systems are included.

  14. 中低速磁悬浮列车控制及网络系统%Medium-low Speed Maglev Train Control and Network System

    Institute of Scientific and Technical Information of China (English)

    粟爱军; 袁文烨; 许义景; 李一叶; 何文惠

    2012-01-01

    介绍了中低速磁悬浮列车控制及网络系统的设计思路与系统组成,从网络控制系统总线、拓扑、功能等角度对网络控制系统进行了阐述,通过车辆逻辑控制模块、列车线的分析,对中低速磁悬浮列车硬线继电控制系统进行了说明.%Design and configuration of network control system for medium-low speed maglev train were presented. Network control system was described from system bus, topology, and functions, etc. With analysis of logical vehicle control module and train line, medium-low speed maglev train hard-wire relay control system was indicated.

  15. TY5KM型接触网作业车低速走行系统%Low Speed Running System of Type TY5KM Catenary Work Vehicle

    Institute of Scientific and Technical Information of China (English)

    臧坤

    2015-01-01

    This paper mainly introduces the main structure, the technical parameters and the main characteristic of the low-speed system of the model TY5KM catenary working car. On the basic of the original power transmission system, the model TY5KM catenary wording car increase a line construction work the low-speed system, the walking speed can stepless speed regulation in 0~10 km/h, implemented the two-way low–speed running, it also on the operation platform and the driv-er’s cab control the low-speed system manipulation. The low-speed system can switch with the main power transmission, adopt pneumatic control oil pump, the motor clutch and when a failure hand control on-off control.%介绍了TY5KM型接触网作业车低速走行系统的主要结构、主要技术参数及主要特点。 TY5KM接触网作业车在原有动力传动系统的基础上加设一套施工作业低速走行系统。走行速度在0~10 km/h范围内无级调速,实现了作业车双向的低速走行,亦可实现在作业车平台上及司机室内控制低速走行操纵。低速走行与主动力传动能够可靠的切换,采用气动操纵油泵、马达离合及故障时手动操纵控制离合。

  16. Lens coupled scintillating screen-CCD X-ray area detector with a high detective quantum efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Andreas (Detector Group, Experiments Division, European Synchrotron Radiation Facility, B.P. 220, 38043 Grenoble (France))

    1994-09-01

    An X-ray area detector consisting essentially of a scintillating screen, a fast objective and a cooled 1242x1152 slow scan CCD camera is described. A detective quantum efficiency (DQE) of >0.3 for a planar field of view of arnothing110 mm and photon energies between 10 and 20 keV is obtainable at integrated intensity levels above 10[sup 8] eV/mm[sup 2]/readout without any image intensification. At lower intensities the readout noise of the CCD camera (8 e[sup -]/pixel) deteriorates the DQE. The spatial resolution of the detector is 100 [mu]m (FWHM) and the dynamic range 10[sup 4]. The design easily allows the exchange of screens in order to optimize the detector at other photon energies. The performance of the detector will be discussed in terms of DQE, dynamic range, spatial resolution, spatial distortion and uniformity of response. The detector will be initially used for small angle scattering and diffraction experiments as part of the Microfocus Beamline at the European Synchrotron Radiation Facility (ESRF). ((orig.))

  17. HIGH SPEED CAMERA

    Science.gov (United States)

    Rogers, B.T. Jr.; Davis, W.C.

    1957-12-17

    This patent relates to high speed cameras having resolution times of less than one-tenth microseconds suitable for filming distinct sequences of a very fast event such as an explosion. This camera consists of a rotating mirror with reflecting surfaces on both sides, a narrow mirror acting as a slit in a focal plane shutter, various other mirror and lens systems as well as an innage recording surface. The combination of the rotating mirrors and the slit mirror causes discrete, narrow, separate pictures to fall upon the film plane, thereby forming a moving image increment of the photographed event. Placing a reflecting surface on each side of the rotating mirror cancels the image velocity that one side of the rotating mirror would impart, so as a camera having this short a resolution time is thereby possible.

  18. Noise analysis for CCD-based ultraviolet and visible spectrophotometry.

    Science.gov (United States)

    Davenport, John J; Hodgkinson, Jane; Saffell, John R; Tatam, Ralph P

    2015-09-20

    We present the results of a detailed analysis of the noise behavior of two CCD spectrometers in common use, an AvaSpec-3648 CCD UV spectrometer and an Ocean Optics S2000 Vis spectrometer. Light sources used include a deuterium UV/Vis lamp and UV and visible LEDs. Common noise phenomena include source fluctuation noise, photoresponse nonuniformity, dark current noise, fixed pattern noise, and read noise. These were identified and characterized by varying light source, spectrometer settings, or temperature. A number of noise-limiting techniques are proposed, demonstrating a best-case spectroscopic noise equivalent absorbance of 3.5×10(-4)  AU for the AvaSpec-3648 and 5.6×10(-4)  AU for the Ocean Optics S2000 over a 30 s integration period. These techniques can be used on other CCD spectrometers to optimize performance.

  19. Status of the Dark Energy Survey Camera (DECam) Project

    Energy Technology Data Exchange (ETDEWEB)

    Flaugher, Brenna L.; Abbott, Timothy M.C.; Angstadt, Robert; Annis, Jim; Antonik, Michelle, L.; Bailey, Jim; Ballester, Otger.; Bernstein, Joseph P.; Bernstein, Rebbeca; Bonati, Marco; Bremer, Gale; /Fermilab /Cerro-Tololo InterAmerican Obs. /ANL /Texas A-M /Michigan U. /Illinois U., Urbana /Ohio State U. /University Coll. London /LBNL /SLAC /IFAE

    2012-06-29

    The Dark Energy Survey Collaboration has completed construction of the Dark Energy Camera (DECam), a 3 square degree, 570 Megapixel CCD camera which will be mounted on the Blanco 4-meter telescope at CTIO. DECam will be used to perform the 5000 sq. deg. Dark Energy Survey with 30% of the telescope time over a 5 year period. During the remainder of the time, and after the survey, DECam will be available as a community instrument. All components of DECam have been shipped to Chile and post-shipping checkout finished in Jan. 2012. Installation is in progress. A summary of lessons learned and an update of the performance of DECam and the status of the DECam installation and commissioning will be presented.

  20. Radiation imaging with a new scintillator and a CMOS camera

    Science.gov (United States)

    Kurosawa, S.; Shoji, Y.; Pejchal, J.; Yokota, Y.; Yoshikawa, A.

    2014-07-01

    A new imaging system consisting of a high-sensitivity complementary metal-oxide semiconductor (CMOS) sensor, a microscope and a new scintillator, Ce-doped Gd3(Al,Ga)5O12 (Ce:GAGG) grown by the Czochralski process, has been developed. The noise, the dark current and the sensitivity of the CMOS camera (ORCA-Flash4.0, Hamamatsu) was revised and compared to a conventional CMOS, whose sensitivity is at the same level as that of a charge coupled device (CCD) camera. Without the scintillator, this system had a good position resolution of 2.1 ± 0.4 μm and we succeeded in obtaining the alpha-ray images using 1-mm thick Ce:GAGG crystal. This system can be applied for example to high energy X-ray beam profile monitor, etc.

  1. CCD sensors in synchrotron X-ray detectors

    Science.gov (United States)

    Strauss, M. G.; Naday, I.; Sherman, I. S.; Kraimer, M. R.; Westbrook, E. M.; Zaluzec, N. J.

    1988-04-01

    The intense photon flux from advanced synchrotron light sources, such as the 7-GeV synchrotron being designed at Argonne, require integrating-type detectors. Charge-coupled devices (CCDs) are well suited as synchrotron X-ray detectors. When irradiated indirectly via a phosphor followed by reducing optics, diffraction patterns of 100 cm 2 can be imaged on a 2 cm 2 CCD. With a conversion efficiency of ˜ 1 CCD electron/X-ray photon, a peak saturation capacity of > 10 6 X-rays can be obtained. A programmable CCD controller operating at a clock frequency of 20 MHz has been developed. The readout rate is 5 × 10 6 pixels/s and the shift rate in the parallel registers is 10 6 lines/s. The test detector was evaluated in two experiments. In protein crystallography diffraction patterns have been obtained from a lysozyme crystal using a conventional rotating anode X-ray generator. Based on these results we expect to obtain at a synchrotron diffraction images at a rate of ˜ 1 frame/s or a complete 3-dimensional data set from a single crystal in ˜ 2 min. In electron energy-loss spectroscopy (EELS), the CCD was used in a parallel detection mode which is similar to the mode array detectors are used in dispersive EXAFS. With a beam current corresponding to 3 × 10 9 electron/s on the detector, a series of 64 spectra were recorded on the CCD in a continuous sequence without interruption due to readout. The frame-to-frame pixel signal fluctuations had σ = 0.4% from which DQE = 0.4 was obtained, where the detector conversion efficiency was 2.6 CCD electrons/X-ray photon. These multiple frame series also showed the time-resolved modulation of the electron microscope optics by stray magnetic fields.

  2. Automatic Camera Control

    DEFF Research Database (Denmark)

    Burelli, Paolo; Preuss, Mike

    2014-01-01

    Automatically generating computer animations is a challenging and complex problem with applications in games and film production. In this paper, we investigate howto translate a shot list for a virtual scene into a series of virtual camera configurations — i.e automatically controlling the virtual...... camera. We approach this problem by modelling it as a dynamic multi-objective optimisation problem and show how this metaphor allows a much richer expressiveness than a classical single objective approach. Finally, we showcase the application of a multi-objective evolutionary algorithm to generate a shot...

  3. Technology validation of the PLATO CCD at ESA

    Science.gov (United States)

    Prod'homme, Thibaut; Verhoeve, Peter; Beaufort, Thierry; Duvet, Ludovic; Lemmel, Frederic; Smit, Hans; Blommaert, Sander; Oosterbroek, Tim; van der Luijt, Cornelis; Visser, Ivo; Heijnen, Jerko; Butler, Bart

    2016-07-01

    PLATO { PLAnetary Transits and Oscillations of stars { is the third medium-class mission to be selected in the European Space Agency (ESA) Science and Robotic Exploration Cosmic Vision programme. Due for launch in 2025, the payload makes use of a large format (8 cm x 8 cm) Charge-Coupled Devices (CCDs) the e2v CCD270 operated at 4 MHz. The manufacture of such large device in large quantity constitutes an unprecedented effort. To de-risk the PLATO CCD procurement and aid the mission definition process, ESA's Payload Technology Validation team is characterizing the electro-optical performance of a number of PLATO devices before and after proton irradiation.

  4. ESA's CCD test bench for the PLATO mission

    Science.gov (United States)

    Beaufort, Thierry; Duvet, Ludovic; Bloemmaert, Sander; Lemmel, Frederic; Prod'homme, Thibaut; Verhoeve, Peter; Smit, Hans; Butler, Bart; van der Luijt, Cornelis; Heijnen, Jerko; Visser, Ivo

    2016-08-01

    PLATO { PLAnetary Transits and Oscillations of stars { is the third medium-class mission to be selected in the European Space Agency (ESA) Science and Robotic Exploration Cosmic Vision programme. Due for launch in 2025, the payload makes use of a large format (8 cm x 8 cm) Charge-Coupled Devices (CCDs), the e2v CCD270 operated at 4 MHz and at -70 C. To de-risk the PLATO CCD qualification programme initiated in 2014 and support the mission definition process, ESA's Payload Technology Validation section from the Future Missions Office has developed a dedicated test bench.

  5. The determination of the intrinsic and extrinsic parameters of virtual camera based on OpenGL

    Science.gov (United States)

    Li, Suqi; Zhang, Guangjun; Wei, Zhenzhong

    2006-11-01

    OpenGL is the international standard of 3D image. The 3D image generation by OpenGL is similar to the shoot by camera. This paper focuses on the application of OpenGL to computer vision, the OpenGL 3D image is regarded as virtual camera image. Firstly, the imaging mechanism of OpenGL has been analyzed in view of perspective projection transformation of computer vision camera. Then, the relationship between intrinsic and extrinsic parameters of camera and function parameters in OpenGL has been analysed, the transformation formulas have been deduced. Thereout the computer vision simulation has been realized. According to the comparison between the actual CCD camera images and virtual camera images(the parameters of actual camera are the same as virtual camera's) and the experiment results of stereo vision 3D reconstruction simulation, the effectiveness of the method with which the intrinsic and extrinsic parameters of virtual camera based on OpenGL are determined has been verified.

  6. The research on calibration methods of dual-CCD laser three-dimensional human face scanning system

    Science.gov (United States)

    Wang, Jinjiang; Chang, Tianyu; Ge, Baozhen; Tian, Qingguo; Yang, Fengting; Shi, Shendong

    2013-09-01

    In this paper, on the basis of considering the performance advantages of two-step method, we combines the stereo matching of binocular stereo vision with active laser scanning to calibrate the system. Above all, we select a reference camera coordinate system as the world coordinate system and unity the coordinates of two CCD cameras. And then obtain the new perspective projection matrix (PPM) of each camera after the epipolar rectification. By those, the corresponding epipolar equation of two cameras can be defined. So by utilizing the trigonometric parallax method, we can measure the space point position after distortion correction and achieve stereo matching calibration between two image points. Experiments verify that this method can improve accuracy and system stability is guaranteed. The stereo matching calibration has a simple process with low-cost, and simplifies regular maintenance work. It can acquire 3D coordinates only by planar checkerboard calibration without the need of designing specific standard target or using electronic theodolite. It is found that during the experiment two-step calibration error and lens distortion lead to the stratification of point cloud data. The proposed calibration method which combining active line laser scanning and binocular stereo vision has the both advantages of them. It has more flexible applicability. Theory analysis and experiment shows the method is reasonable.

  7. LSST camera readout chip ASPIC: test tools

    Science.gov (United States)

    Antilogus, P.; Bailly, Ph; Jeglot, J.; Juramy, C.; Lebbolo, H.; Martin, D.; Moniez, M.; Tocut, V.; Wicek, F.

    2012-02-01

    The LSST camera will have more than 3000 video-processing channels. The readout of this large focal plane requires a very compact readout chain. The correlated ''Double Sampling technique'', which is generally used for the signal readout of CCDs, is also adopted for this application and implemented with the so called ''Dual Slope integrator'' method. We have designed and implemented an ASIC for LSST: the Analog Signal Processing asIC (ASPIC). The goal is to amplify the signal close to the output, in order to maximize signal to noise ratio, and to send differential outputs to the digitization. Others requirements are that each chip should process the output of half a CCD, that is 8 channels and should operate at 173 K. A specific Back End board has been designed especially for lab test purposes. It manages the clock signals, digitizes the analog differentials outputs of ASPIC and stores data into a memory. It contains 8 ADCs (18 bits), 512 kwords memory and an USB interface. An FPGA manages all signals from/to all components on board and generates the timing sequence for ASPIC. Its firmware is written in Verilog and VHDL languages. Internals registers permit to define various tests parameters of the ASPIC. A Labview GUI allows to load or update these registers and to check a proper operation. Several series of tests, including linearity, noise and crosstalk, have been performed over the past year to characterize the ASPIC at room and cold temperature. At present, the ASPIC, Back-End board and CCD detectors are being integrated to perform a characterization of the whole readout chain.

  8. Communities, Cameras, and Conservation

    Science.gov (United States)

    Patterson, Barbara

    2012-01-01

    Communities, Cameras, and Conservation (CCC) is the most exciting and valuable program the author has seen in her 30 years of teaching field science courses. In this citizen science project, students and community volunteers collect data on mountain lions ("Puma concolor") at four natural areas and public parks along the Front Range of Colorado.…

  9. Make a Pinhole Camera

    Science.gov (United States)

    Fisher, Diane K.; Novati, Alexander

    2009-01-01

    On Earth, using ordinary visible light, one can create a single image of light recorded over time. Of course a movie or video is light recorded over time, but it is a series of instantaneous snapshots, rather than light and time both recorded on the same medium. A pinhole camera, which is simple to make out of ordinary materials and using ordinary…

  10. Underwater camera with depth measurement

    Science.gov (United States)

    Wang, Wei-Chih; Lin, Keng-Ren; Tsui, Chi L.; Schipf, David; Leang, Jonathan

    2016-04-01

    The objective of this study is to develop an RGB-D (video + depth) camera that provides three-dimensional image data for use in the haptic feedback of a robotic underwater ordnance recovery system. Two camera systems were developed and studied. The first depth camera relies on structured light (as used by the Microsoft Kinect), where the displacement of an object is determined by variations of the geometry of a projected pattern. The other camera system is based on a Time of Flight (ToF) depth camera. The results of the structural light camera system shows that the camera system requires a stronger light source with a similar operating wavelength and bandwidth to achieve a desirable working distance in water. This approach might not be robust enough for our proposed underwater RGB-D camera system, as it will require a complete re-design of the light source component. The ToF camera system instead, allows an arbitrary placement of light source and camera. The intensity output of the broadband LED light source in the ToF camera system can be increased by putting them into an array configuration and the LEDs can be modulated comfortably with any waveform and frequencies required by the ToF camera. In this paper, both camera were evaluated and experiments were conducted to demonstrate the versatility of the ToF camera.

  11. Evaluation of the photoelectric performance parameters measurement for electron multiplying CCD

    Science.gov (United States)

    Fang, Jie; Zhang, Wenwen; Gao, Jin; Li, Chaowei; Chen, Qian; Gu, Guohua

    2016-10-01

    The measurement of the electron multiplying CCD(EMCCD) photoelectric performance parameters plays an important role in the development of the chip and imaging system. Measurement uncertainty is an important index to evaluate the quality of the measurement results. A measurement platform for EMCCD photoelectric performance parameters is set up. An EMCCD camera's photoelectric performance parameters are measured based on photon transfer technique and the uncertainty of the measurement results is analyzed. Based on the method of GUM, the influences of the integrating sphere light source stability, EMCCD camera electronics system stability, installation posture, stray light in dark environment, camera's digital resolution and measurement sampling on the measurement results are analyzed. Based on the theoretical model of different photoelectric performance parameters, the uncertainty sources are discussed. The combined standard uncertainty is determined by the type A uncertainty and the type B uncertainty. The uncertainty evaluation model is established for the measurement of EMCCD photoelectric performance parameters, including convert gain, readout noise, full well, signal to noise ratio and multiplication gain. The uncertainty of the measurement results is calculated by using the established model. At last, we get the following results: relative standard uncertainty of the convert gain is 0.637% (k = 1), relative standard uncertainty of the readout noise is 0.653% (k = 1), relative standard uncertainty of the full well is 2.384% (k = 1), relative standard uncertainty of the signal to noise ratio is 2.301% (k = 1) and relative standard uncertainty of the multiplication gain is 1.259% (k = 1). The above uncertainty results show that the measurement results of this paper are accurate and reliable.

  12. 3D digital image correlation using single color camera pseudo-stereo system

    Science.gov (United States)

    Li, Junrui; Dan, Xizuo; Xu, Wan; Wang, Yonghong; Yang, Guobiao; Yang, Lianxiang

    2017-10-01

    Three dimensional digital image correlation (3D-DIC) has been widely used by industry to measure the 3D contour and whole-field displacement/strain. In this paper, a novel single color camera 3D-DIC setup, using a reflection-based pseudo-stereo system, is proposed. Compared to the conventional single camera pseudo-stereo system, which splits the CCD sensor into two halves to capture the stereo views, the proposed system achieves both views using the whole CCD chip and without reducing the spatial resolution. In addition, similarly to the conventional 3D-DIC system, the center of the two views stands in the center of the CCD chip, which minimizes the image distortion relative to the conventional pseudo-stereo system. The two overlapped views in the CCD are separated by the color domain, and the standard 3D-DIC algorithm can be utilized directly to perform the evaluation. The system's principle and experimental setup are described in detail, and multiple tests are performed to validate the system.

  13. Validation of spectral sky radiance derived from all-sky camera images – a case study

    Directory of Open Access Journals (Sweden)

    K. Tohsing

    2014-01-01

    Full Text Available Spectral sky radiance (380–760 nm is derived from measurements with a Hemispherical Sky Imager (HSI system. The HSI consists of a commercial compact CCD (charge coupled device camera equipped with a fish-eye lens and provides hemispherical sky images in three reference bands such as red, green and blue. To obtain the spectral sky radiance from these images non-linear regression functions for various sky conditions have been derived. The camera-based spectral sky radiance was validated by spectral sky radiance measured with a CCD spectroradiometer. The spectral sky radiance for complete distribution over the hemisphere between both instruments deviates by less than 20% at 500 nm for all sky conditions and for zenith angles less than 80°. The reconstructed spectra of the wavelength 380 nm to 760 nm between both instruments at various directions deviate by less then 20% for all sky conditions.

  14. Validation of spectral sky radiance derived from all-sky camera images – a case study

    Directory of Open Access Journals (Sweden)

    K. Tohsing

    2014-07-01

    Full Text Available Spectral sky radiance (380–760 nm is derived from measurements with a hemispherical sky imager (HSI system. The HSI consists of a commercial compact CCD (charge coupled device camera equipped with a fish-eye lens and provides hemispherical sky images in three reference bands such as red, green and blue. To obtain the spectral sky radiance from these images, non-linear regression functions for various sky conditions have been derived. The camera-based spectral sky radiance was validated using spectral sky radiance measured with a CCD spectroradiometer. The spectral sky radiance for complete distribution over the hemisphere between both instruments deviates by less than 20% at 500 nm for all sky conditions and for zenith angles less than 80°. The reconstructed spectra of the wavelengths 380–760 nm between both instruments at various directions deviate by less than 20% for all sky conditions.

  15. Development of an n-channel CCD, CCD-NeXT1, for Soft X-ray Imager onboard the NeXT satellite

    CERN Document Server

    Takagi, Shin-ichiro; Inui, Tatsuya; Matsumoto, Hironori; Koyama, Katsuji; Ozawa, Hideki; Tohiguchi, Masakuni; Matsuura, Daisuke; Miyata, Emi; Tsunemi, Hiroshi; Miyaguchi, Kazuhisa; Maeda, Kentaro; Kohno, Hirohiko

    2007-01-01

    NeXT (New X-ray Telescope) is the next Japanese X-ray astronomical satellite mission after the Suzaku satellite. NeXT aims to perform wide band imaging spectroscopy. Due to the successful development of a multilayer coated mirror, called a supermirror, NeXT can focus X-rays in the energy range from 0.1 keV up to 80 keV. To cover this wide energy range, we are in the process of developing a hybrid X-ray camera, Wideband X-ray Imager (WXI) as a focal plane detector of the supermirror. The WXI consists of X-ray CCDs (SXI) and CdTe pixelized detectors (HXI), which cover the lower and higher X-ray energy bands of 0.1-80 keV, respectively. The X-ray CCDs of the SXI are stacked above the CdTe pixelized detectors of the HXI. The X-ray CCDs of the SXI detect soft X-rays below $\\sim$ 10 keV and allow hard X-rays pass into the CdTe detectors of the HXI without loss. Thus, we have been developing a "back-supportless CCD" with a thick depletion layer, a thinned silicon wafer, and a back-supportless structure. In this pape...

  16. The PAU Camera

    Science.gov (United States)

    Casas, R.; Ballester, O.; Cardiel-Sas, L.; Carretero, J.; Castander, F. J.; Castilla, J.; Crocce, M.; de Vicente, J.; Delfino, M.; Fernández, E.; Fosalba, P.; García-Bellido, J.; Gaztañaga, E.; Grañena, F.; Jiménez, J.; Madrid, F.; Maiorino, M.; Martí, P.; Miquel, R.; Neissner, C.; Ponce, R.; Sánchez, E.; Serrano, S.; Sevilla, I.; Tonello, N.; Troyano, I.

    2011-11-01

    The PAU Camera (PAUCam) is a wide-field camera designed to be mounted at the William Herschel Telescope (WHT) prime focus, located at the Observatorio del Roque de los Muchachos in the island of La Palma (Canary Islands).Its primary function is to carry out a cosmological survey, the PAU Survey, covering an area of several hundred square degrees of sky. Its purpose is to determine positions and distances using photometric redshift techniques. To achieve accurate photo-z's, PAUCam will be equipped with 40 narrow-band filters covering the range from 450 to850 nm, and six broad-band filters, those of the SDSS system plus the Y band. To fully cover the focal plane delivered by the telescope optics, 18 CCDs 2k x 4k are needed. The pixels are square of 15 μ m size. The optical characteristics of the prime focus corrector deliver a field-of-view where eight of these CCDs will have an illumination of more than 95% covering a field of 40 arc minutes. The rest of the CCDs will occupy the vignetted region extending the field diameter to one degree. Two of the CCDs will be devoted to auto-guiding.This camera have some innovative features. Firstly, both the broad-band and the narrow-band filters will be placed in mobile trays, hosting 16 such filters at most. Those are located inside the cryostat at few millimeters in front of the CCDs when observing. Secondly, a pressurized liquid nitrogen tank outside the camera will feed a boiler inside the cryostat with a controlled massflow. The read-out electronics will use the Monsoon architecture, originally developed by NOAO, modified and manufactured by our team in the frame of the DECam project (the camera used in the DES Survey).PAUCam will also be available to the astronomical community of the WHT.

  17. Image Sensors Enhance Camera Technologies

    Science.gov (United States)

    2010-01-01

    In the 1990s, a Jet Propulsion Laboratory team led by Eric Fossum researched ways of improving complementary metal-oxide semiconductor (CMOS) image sensors in order to miniaturize cameras on spacecraft while maintaining scientific image quality. Fossum s team founded a company to commercialize the resulting CMOS active pixel sensor. Now called the Aptina Imaging Corporation, based in San Jose, California, the company has shipped over 1 billion sensors for use in applications such as digital cameras, camera phones, Web cameras, and automotive cameras. Today, one of every three cell phone cameras on the planet feature Aptina s sensor technology.

  18. MISR radiometric camera-by-camera Cloud Mask V004

    Data.gov (United States)

    National Aeronautics and Space Administration — This file contains the Radiometric camera-by-camera Cloud Mask dataset. It is used to determine whether a scene is classified as clear or cloudy. A new parameter has...

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

    Science.gov (United States)

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

    2017-06-01

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

  20. Pixel Stability in HST Advanced Camera for Surveys Images

    Science.gov (United States)

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

    2017-06-01

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

  1. Absolute calibration of a charge-coupled device camera with twin beams

    Energy Technology Data Exchange (ETDEWEB)

    Meda, A.; Ruo-Berchera, I., E-mail: i.ruoberchera@inrim.it; Degiovanni, I. P.; Brida, G.; Rastello, M. L.; Genovese, M. [Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino (Italy)

    2014-09-08

    We report on the absolute calibration of a Charge-Coupled Device (CCD) camera by exploiting quantum correlation. This method exploits a certain number of spatial pairwise quantum correlated modes produced by spontaneous parametric-down-conversion. We develop a measurement model accounting for all the uncertainty contributions, and we reach the relative uncertainty of 0.3% in low photon flux regime. This represents a significant step forward for the characterization of (scientific) CCDs used in mesoscopic light regime.

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

    Science.gov (United States)

    Kimble, Randy

    2008-01-01

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

  3. Slew Maneuver Control for Spacecraft Equipped with Star Camera and Reaction Wheels

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    2005-01-01

    A configuration consisting of a star camera, four reaction wheels and magnetorquers for momentum unloading has become standard for many spacecraft missions. This popularity has motivated numerous agencies and private companies to initiate work on the design of an imbedded attitude control system...... realized on an integrated circuit. This paper provides an easily implementable control algorithm for this type of configuration. The paper considers two issues: slew maneuver with a feature of avoiding direct exposure of the camera's CCD chip to the Sun %, three-axis attitude control and optimal control...

  4. Positioning of Screw Holes Group Based on Digital Camera and Digital Control Drilling

    Institute of Scientific and Technical Information of China (English)

    FENG Wenhao; LI Jiansong; YAN Li; SU Guozhong; YUAN Xiuxiao; ZHONG Shengzhang; JI Huiming

    2004-01-01

    Positioning of screw holes is an important production procedure for steel construction connecting with bolts. In this paper, a new production method is presented, in which the digital camera is used for taking pictures of screw holes and other techniques are advanced. This paper also indicates that the pixels of CCD chip in photogrammetry should be chosen as all geometric units in an image, such as interior elements and all kinds of distortions. The measure can also simplify the camera calibration for determining the size of non-square pixel.

  5. LLiST - a new star tracker camera for tip-tilt correction at IOTA

    CERN Document Server

    Schuller, P A; Lydon, D; McGonagle, W H; Pedretti, E; Reich, R K; Schloerb, F P; Traub, W A

    2004-01-01

    The tip-tilt correction system at the Infrared Optical Telescope Array (IOTA) has been upgraded with a new star tracker camera. The camera features a backside-illuminated CCD chip offering doubled overall quantum efficiency and a four times higher system gain compared to the previous system. Tests carried out to characterize the new system showed a higher system gain with a lower read-out noise electron level. Shorter read-out cycle times now allow to compensate tip-tilt fluctuations so that their error imposed on visibility measurements becomes comparable to, and even smaller than, that of higher-order aberrations.

  6. General Attitude Control Algorithm for Spacecraft Equipped with Star Camera and Reaction Wheels

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    A configuration consisting of a star camera, four reaction wheels and magnetorquers for momentum unloading has become standard for many spacecraft missions. This popularity has motivated numerous agencies and private companies to initiate work on the design of an imbedded attitude control system...... realized on an integrated circuit. This paper considers two issues: slew maneuver with a feature of avoiding direct exposure of the camera's CCD chip to the Sun %, three-axis attitude control and optimal control torque distribution in a reaction wheel assembly. The attitude controller is synthesized...

  7. The LSST Camera 500 watt -130 degC Mixed Refrigerant Cooling System

    Energy Technology Data Exchange (ETDEWEB)

    Bowden, Gordon B.; Langton, Brian J.; /SLAC; Little, William A.; /MMR-Technologies, Mountain View, CA; Powers, Jacob R; Schindler, Rafe H.; /SLAC; Spektor, Sam; /MMR-Technologies, Mountain View, CA

    2014-05-28

    The LSST Camera has a higher cryogenic heat load than previous CCD telescope cameras due to its large size (634 mm diameter focal plane, 3.2 Giga pixels) and its close coupled front-end electronics operating at low temperature inside the cryostat. Various refrigeration technologies are considered for this telescope/camera environment. MMR-Technology’s Mixed Refrigerant technology was chosen. A collaboration with that company was started in 2009. The system, based on a cluster of Joule-Thomson refrigerators running a special blend of mixed refrigerants is described. Both the advantages and problems of applying this technology to telescope camera refrigeration are discussed. Test results from a prototype refrigerator running in a realistic telescope configuration are reported. Current and future stages of the development program are described. (auth)

  8. Overview of the ARGOS X-ray framing camera for Laser MegaJoule

    Energy Technology Data Exchange (ETDEWEB)

    Trosseille, C., E-mail: clement.trosseille@cea.fr; Aubert, D.; Auger, L.; Bazzoli, S.; Brunel, P.; Burillo, M.; Chollet, C.; Jasmin, S.; Maruenda, P.; Moreau, I.; Oudot, G.; Raimbourg, J.; Soullié, G.; Stemmler, P.; Zuber, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Beck, T. [CEA, DEN, CADARACHE, F-13108 St Paul lez Durance (France); Gazave, J. [CEA, DAM, CESTA, F-33116 Le Barp (France)

    2014-11-15

    Commissariat à l’Énergie Atomique et aux Énergies Alternatives has developed the ARGOS X-ray framing camera to perform two-dimensional, high-timing resolution imaging of an imploding target on the French high-power laser facility Laser MegaJoule. The main features of this camera are: a microchannel plate gated X-ray detector, a spring-loaded CCD camera that maintains proximity focus in any orientation, and electronics packages that provide remotely-selectable high-voltages to modify the exposure-time of the camera. These components are integrated into an “air-box” that protects them from the harsh environmental conditions. A miniaturized X-ray generator is also part of the device for in situ self-testing purposes.

  9. Combining HJ CCD, GF-1 WFV and MODIS Data to Generate Daily High Spatial Resolution Synthetic Data for Environmental Process Monitoring.

    Science.gov (United States)

    Wu, Mingquan; Huang, Wenjiang; Niu, Zheng; Wang, Changyao

    2015-08-20

    The limitations of satellite data acquisition mean that there is a lack of satellite data with high spatial and temporal resolutions for environmental process monitoring. In this study, we address this problem by applying the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) and the Spatial and Temporal Data Fusion Approach (STDFA) to combine Huanjing satellite charge coupled device (HJ CCD), Gaofen satellite no. 1 wide field of view camera (GF-1 WFV) and Moderate Resolution Imaging Spectroradiometer (MODIS) data to generate daily high spatial resolution synthetic data for land surface process monitoring. Actual HJ CCD and GF-1 WFV data were used to evaluate the precision of the synthetic images using the correlation analysis method. Our method was tested and validated for two study areas in Xinjiang Province, China. The results show that both the ESTARFM and STDFA can be applied to combine HJ CCD and MODIS reflectance data, and GF-1 WFV and MODIS reflectance data, to generate synthetic HJ CCD data and synthetic GF-1 WFV data that closely match actual data with correlation coefficients (r) greater than 0.8989 and 0.8643, respectively. Synthetic red- and near infrared (NIR)-band data generated by ESTARFM are more suitable for the calculation of Normalized Different Vegetation Index (NDVI) than the data generated by STDFA.

  10. Vision system for driving control using camera mounted on an automatic vehicle. Jiritsu sokosha no camera ni yoru shikaku system

    Energy Technology Data Exchange (ETDEWEB)

    Nishimori, K.; Ishihara, K.; Tokutaka, H.; Kishida, S.; Fujimura, K. (Tottori University, Tottori (Japan). Faculty of Engineering); Okada, M. (Mazda Corp., Hiroshima (Japan)); Hirakawa, S. (Fujitsu Corp., Tokyo (Japan))

    1993-11-30

    The present report explains a vision system, in which a CCD camera, used for the model vehicle automatically traveling by fuzzy control, is used as a vision sensor. The vision system is composed of input image processing module, situation recognition/analysis module to three-dimensionally recover the road, route-selecting navigation module to avoid the obstacle and vehicle control module. The CCD camera is used as a vision sensor to make the model vehicle automatically travel by fuzzy control with the above modules. In the present research, the traveling is controlled by treating the position and configuration of objective in image as a fuzzy inferential variable. Based on the above method, the traveling simulation gave the following knowledge: even with the image information only from the vision system, the application of fuzzy control facilitates the traveling. If the objective is clearly known, the control is judged able to be made even from vague image which does not necessitate the exact locative information. 4 refs., 11 figs.

  11. MTF online compensation in space optical remote sensing camera

    Science.gov (United States)

    Qu, Youshan; Zhai, Bo; Han, Yameng; Zhou, Jiang

    2015-02-01

    An ordinary space optical remote sensing camera is an optical diffraction-limited system and a low-pass filter from the theory of Fourier Optics, and all the digital imaging sensors, whether the CCD or CMOS, are low-pass filters as well. Therefore, when the optical image with abundant high-frequency components passes through an optical imaging system, the profuse middle-frequency information is attenuated and the rich high-frequency information is lost, which will blur the remote sensing image. In order to overcome this shortcoming of the space optical remote sensing camera, an online compensating approach of the Modulation Transfer Function in the space cameras is designed. The designed method was realized by a hardware analog circuit placed before the A/D converter, which was composed of adjustable low-pass filters with a calculated value of quality factor Q. Through the adjustment of the quality factor Q of the filters, the MTF of the processed image is compensated. The experiment results display that the realized compensating circuit in a space optical camera is capable of improving the MTF of an optical remote sensing imaging system 30% higher than that of no compensation. This quantized principle can efficiently instruct the MTF compensating circuit design in practice.

  12. Volumetric particle image velocimetry with a single plenoptic camera

    Science.gov (United States)

    Fahringer, Timothy W.; Lynch, Kyle P.; Thurow, Brian S.

    2015-11-01

    A novel three-dimensional (3D), three-component (3C) particle image velocimetry (PIV) technique based on volume illumination and light field imaging with a single plenoptic camera is described. A plenoptic camera uses a densely packed microlens array mounted near a high resolution image sensor to sample the spatial and angular distribution of light collected by the camera. The multiplicative algebraic reconstruction technique (MART) computed tomography algorithm is used to reconstruct a volumetric intensity field from individual snapshots and a cross-correlation algorithm is used to estimate the velocity field from a pair of reconstructed particle volumes. This work provides an introduction to the basic concepts of light field imaging with a plenoptic camera and describes the unique implementation of MART in the context of plenoptic image data for 3D/3C PIV measurements. Simulations of a plenoptic camera using geometric optics are used to generate synthetic plenoptic particle images, which are subsequently used to estimate the quality of particle volume reconstructions at various particle number densities. 3D reconstructions using this method produce reconstructed particles that are elongated by a factor of approximately 4 along the optical axis of the camera. A simulated 3D Gaussian vortex is used to test the capability of single camera plenoptic PIV to produce a 3D/3C vector field, where it was found that lateral displacements could be measured to approximately 0.2 voxel accuracy in the lateral direction and 1 voxel in the depth direction over a 300× 200× 200 voxel volume. The feasibility of the technique is demonstrated experimentally using a home-built plenoptic camera based on a 16-megapixel interline CCD camera and a 289× 193 array of microlenses and a pulsed Nd:YAG laser. 3D/3C measurements were performed in the wake of a low Reynolds number circular cylinder and compared with measurements made using a conventional 2D/2C PIV system. Overall, single camera

  13. Accuracy Potential and Applications of MIDAS Aerial Oblique Camera System

    Science.gov (United States)

    Madani, M.

    2012-07-01

    Airborne oblique cameras such as Fairchild T-3A were initially used for military reconnaissance in 30s. A modern professional digital oblique camera such as MIDAS (Multi-camera Integrated Digital Acquisition System) is used to generate lifelike three dimensional to the users for visualizations, GIS applications, architectural modeling, city modeling, games, simulators, etc. Oblique imagery provide the best vantage for accessing and reviewing changes to the local government tax base, property valuation assessment, buying & selling of residential/commercial for better decisions in a more timely manner. Oblique imagery is also used for infrastructure monitoring making sure safe operations of transportation, utilities, and facilities. Sanborn Mapping Company acquired one MIDAS from TrackAir in 2011. This system consists of four tilted (45 degrees) cameras and one vertical camera connected to a dedicated data acquisition computer system. The 5 digital cameras are based on the Canon EOS 1DS Mark3 with Zeiss lenses. The CCD size is 5,616 by 3,744 (21 MPixels) with the pixel size of 6.4 microns. Multiple flights using different camera configurations (nadir/oblique (28 mm/50 mm) and (50 mm/50 mm)) were flown over downtown Colorado Springs, Colorado. Boresight fights for 28 mm nadir camera were flown at 600 m and 1,200 m and for 50 mm nadir camera at 750 m and 1500 m. Cameras were calibrated by using a 3D cage and multiple convergent images utilizing Australis model. In this paper, the MIDAS system is described, a number of real data sets collected during the aforementioned flights are presented together with their associated flight configurations, data processing workflow, system calibration and quality control workflows are highlighted and the achievable accuracy is presented in some detail. This study revealed that the expected accuracy of about 1 to 1.5 GSD (Ground Sample Distance) for planimetry and about 2 to 2.5 GSD for vertical can be achieved. Remaining systematic

  14. Image Mosaicking Approach for a Double-Camera System in the GaoFen2 Optical Remote Sensing Satellite Based on the Big Virtual Camera.

    Science.gov (United States)

    Cheng, Yufeng; Jin, Shuying; Wang, Mi; Zhu, Ying; Dong, Zhipeng

    2017-06-20

    The linear array push broom imaging mode is widely used for high resolution optical satellites (HROS). Using double-cameras attached by a high-rigidity support along with push broom imaging is one method to enlarge the field of view while ensuring high resolution. High accuracy image mosaicking is the key factor of the geometrical quality of complete stitched satellite imagery. This paper proposes a high accuracy image mosaicking approach based on the big virtual camera (BVC) in the double-camera system on the GaoFen2 optical remote sensing satellite (GF2). A big virtual camera can be built according to the rigorous imaging model of a single camera; then, each single image strip obtained by each TDI-CCD detector can be re-projected to the virtual detector of the big virtual camera coordinate system using forward-projection and backward-projection to obtain the corresponding single virtual image. After an on-orbit calibration and relative orientation, the complete final virtual image can be obtained by stitching the single virtual images together based on their coordinate information on the big virtual detector image plane. The paper subtly uses the concept of the big virtual camera to obtain a stitched image and the corresponding high accuracy rational function model (RFM) for concurrent post processing. Experiments verified that the proposed method can achieve seamless mosaicking while maintaining the geometric accuracy.

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

    Science.gov (United States)

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

    2015-04-01

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

  16. Combustion pinhole camera system

    Science.gov (United States)

    Witte, Arvel B.

    1984-02-21

    A pinhole camera system utilizing a sealed optical-purge assembly which provides optical access into a coal combustor or other energy conversion reactors. The camera system basically consists of a focused-purge pinhole optical port assembly, a conventional TV vidicon receiver, an external, variable density light filter which is coupled electronically to the vidicon automatic gain control (agc). The key component of this system is the focused-purge pinhole optical port assembly which utilizes a purging inert gas to keep debris from entering the port and a lens arrangement which transfers the pinhole to the outside of the port assembly. One additional feature of the port assembly is that it is not flush with the interior of the combustor.

  17. Evaluation of the hybrid III and Q-series pediatric ATD upper neck loads as compared to pediatric volunteers in low-speed frontal crashes.

    Science.gov (United States)

    Seacrist, Thomas; Mathews, Emily A; Balasubramanian, Sriram; Maltese, Matthew R; Arbogast, Kristy B

    2013-11-01

    Debate exists in the automotive community regarding the validity of the pediatric ATD neck response and corresponding neck loads. Previous research has shown that the pediatric ATDs exhibit hyper-flexion and chin-to-chest contact resulting in overestimations of neck loads and neck injury criteria. Our previous work comparing the kinematics of the Hybrid III and Q-series 6 and 10-year-old ATDs to pediatric volunteers in low-speed frontal sled tests revealed decreased ATD cervical and thoracic spine excursions. These kinematic differences may contribute to the overestimation of upper neck loads by the ATD. The current study compared upper neck loads of the Hybrid III and Q-series 6 and 10-year-old ATDs against size-matched male pediatric volunteers in low-speed frontal sled tests. A 3-D near-infrared target tracking system quantified the position of markers on the ATD and pediatric volunteers (head top, nasion, bilateral external auditory meatus). Shear force (F x ), axial force (F z ), bending moment (M y ), and head angular acceleration ([Formula: see text]) were calculated about the upper neck using standard equations of motion. In general, the ATDs underestimated axial force and overestimated bending moment compared to the human volunteers. The Hybrid III 6, Q6, and Q10 exhibited reduced head angular acceleration and modest increases in upper neck shear compared to the pediatric volunteers. The reduction in axial force and bending moment has important implications for neck injury predictions as both are used when calculating N ij . These analyses provide insight into the biofidelity of the pediatric ATD upper neck loads in low-speed crash environments.

  18. 中低速磁浮道岔组装测量技术研究%Measurement Technology Research on Assembling of Middle-low Speed Maglev Turnout

    Institute of Scientific and Technical Information of China (English)

    郑莹

    2016-01-01

    Combined with the assembly measurement for the domestic first middle-low maglev transit operation line and the measurement requirements of high precision dimension and shape in the middle-low speed maglev turnout,this paper put forward the methods of basic measuring and positioning,turnout beam measurement positioning and F rail measurement po-sitioning.The operation results showed that the use of instrument measuring tools such as high precision total station instru-ment,straightedge and steel wire string,successfully completed the assembling and measuring of middle-low speed maglev turnout,and could meet the measurement requirements of high precision dimension and shape in the middle-low speed ma-glev turnout.%结合国内首条中低速磁浮交通运营线道岔的组装测量以及中低速磁浮道岔高精度尺寸和形位的测量要求,提出了中低速磁浮道岔基础测量定位、道岔梁测量定位及 F 轨测量定位测量方法,运用结果表明利用高精度全站仪及直尺、钢丝弦线等仪器量具,成功完成了中低速磁浮道岔的组装测量,满足了中低速磁浮道岔高精度尺寸和形位的测量要求。

  19. 大型低风速风电场运行分析%An Analysis of Large Low-speed Wind Farm Operation

    Institute of Scientific and Technical Information of China (English)

    张小雷; 高崇伦; 吴爱国

    2013-01-01

      近年来,风能资源丰富的区域受到资源和规模等因素的限制,人们悄然把目光转向更为广阔的低风速区域。安徽来安低风速风电场是全国首个低风速风电场。本文介绍了来安风电场的基本情况,从海拔高度对发电量的影响、森林(粗糙度)对发电量的影响、风切变和湍流强度对功率曲线的影响等四个方面分析风电场的运行情况,总结了低风速风电场运行的特点和部分规律,为以后风电场建设提供参考。%In recent years, the development of wind areas with rich wind resource gradually is limited by the resources and the scale of wind farm. People turned to explore broad low-speed wind area.The low-speed wind farm of Lai'an is the frst one in China.The paper introduced the main situation of the Lai'an wind farm. According to comparison of the impact of altitude and forest(roughness) for power generation, the impact of wind shear and turbulence intensity for the power curve, this paper analyzed the operating conditions of the wind farm and summed up the characteristics and regularities of low-speed wind farm operation. It aims to provide reference for the future construction of the wind farm.

  20. Pulsed Doppler Radar for Low Speed Target Detection%脉冲多普勒雷达低速目标检测技术

    Institute of Scientific and Technical Information of China (English)

    郭玲红; 李亚立

    2012-01-01

    The principles of pulsed doppler radar for target detection and the characteristics of low speed target detection are analysed. The leakages of emission signal, local oscillator signal, frequency multiply signal of synchronizing pulse and crystal oscillator output are the reasons that effecting of pulsed doppler radar on the low speed target detection. So isolation' s raising, wideband signal reception and emission signal frequency offset are the solution measures to realize low speed target detection effectively. Experimental study proved the validity of analysis and measures.%通过对脉冲多普勒雷达目标检测原理和低速目标检测特点的分析,确定了来自于雷达系统中的发射信号泄露、本振信号泄露、同步脉冲及DDS信号倍频分量泄露、晶振信号倍频分量泄露等是影响脉冲多普勒雷达对于低速目标检测的主要因素,依托现有硬件水平,通过提高系统的收发隔离度、采用宽带接收和发射频率预偏移等技术措施,保证泄漏信号远小于回波信号,从而有效地实现了对低速目标的检测,并通过实验验证了设计的正确性和措施的有效性。