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浏览/检索结果: 共18条，第1-10条 帮助

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Instrument performance and simulation verification of the polar detector 期刊论文  iSwitch采集
Nuclear instruments & methods in physics research section a-accelerators spectrometers detectors and associated equipment, 2017, 卷号: 872, 页码: 28-40
作者:  Kole, M.;  Li, Z. H.;  Produit, N.;  Tymieniecka, T.;  Zhang, J.
收藏  |  浏览/下载：59/0  |  提交时间：2019/04/23
Instrument performance and simulation verification of the POLAR detector 期刊论文  OAI收割
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 2017, 卷号: 872, 页码: 28-40
作者:  Zhang, J;  Kole, M;  Li ZH(李正恒);  Zhang J(张娟);  Bao TW(鲍天威)
  |  收藏  |  浏览/下载：62/0  |  提交时间：2019/08/27
Line-feature-based calibration method of structured light plane parameters for robot hand-eye system 期刊论文  OAI收割
OPTICAL ENGINEERING, 2013, 卷号: 52, 期号: 3
作者:  Qi, Yuhan;  Jing, Fengshui;  Tan, Min
收藏  |  浏览/下载：42/0  |  提交时间：2015/08/12
Design of the real-time autofocusing system for collimator with long focus length and large aperture (EI CONFERENCE) 会议论文  OAI收割
2011 International Academic Conference on Numbers, Intelligence, Manufacturing Technology and Machinery Automation, MAMT 2011, December 24, 2011 - December 25, 2011, Wuhan, China
作者:  Zhang X.;  Zhang X.;  Zhang X.
收藏  |  浏览/下载：42/0  |  提交时间：2013/03/25
Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment  the large aperture collimator's accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However  the process of adjusting the collimator is extremely complicated due to the collimator's large aperture and long focal length. So it is difficult to ensure the measurement's quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above  this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror  semiconductor lasers as light source and CCD sensor as receiver. The system is smaller  lighter  and more convenient when using. The computer simulation shows that the autofocusing system's resolution could reach the accuracy of 40m. If we use the relevant algorithms to execute the sub-pixel scanning  the resolution could reach the accuracy of 10m. It shows that the system could satisfy the required testing precision of testing large aperture optical device.  
The vegetation cover dynamics (1982-2006) in different erosion regions of the Yellow River Basin, China SCI/SSCI论文  OAI收割
2012
作者:  Yang L.;  Gao Y.
收藏  |  浏览/下载：17/0  |  提交时间：2012/09/04
Performance test of steel tube enclosed thermistors in air temperature measurements (EI CONFERENCE) 会议论文  OAI收割
3rd International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2011, January 6, 2011 - January 7, 2011, Shanghai, China
作者:  Yang H.;  Yan F.;  Yan F.;  Peng J.
收藏  |  浏览/下载：32/0  |  提交时间：2013/03/25
The performances of two steel tube enclosed precision thermistors are tested in a well controlled air environment to determine if the thermistors have enough accuracy for 0.01C levels of air temperature gradient measurement. Three Fluke's 5641 and three 5610 thermistors were tested for 24 hours in Fluke's 7008 calibration bath in the first step. In the second step  the performances of these two thermistors in steady state and transient state air temperature environments were tested for 8 hours separately. The results illustrate that  two of the 5641s were airproofed in a temperature well controlled tube  when steel tube enclosed precision thermistors are used in air temperature measurement  there are unstable departures from each other with a maximum 8.8 mC in constant air medium and 27 mC in temperature changing air medium. The transient-time errors are too large to show the true amounts of temperature changes for air temperature measurement. 2011 IEEE.  
A small thickness measurement system based on PSD and FPGA (EI CONFERENCE) 会议论文  OAI收割
3rd International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2011, January 6, 2011 - January 7, 2011, Shanghai, China
作者:  Guo J.;  Guo J.;  He X.
收藏  |  浏览/下载：30/0  |  提交时间：2013/03/25
Considering that the requirement of industrial manufacture  An AT89S51 singlechip works as the core processor of the system. By two laser triangulation  a small thickness measurement system based on PSD and FPGA is presented. It takes S3931 PSD of one dimension as position detection device  A FPGA produces logic control signals for the whole system  the small displacement is converted to differential voltages  which is made by Hamamatsu in Japan  and after amplification and A/D transformation  8-bit parallel data is send to singlechip from FPGA by external interrupts  and the final calculation results output to the LCD display module. After digital micro meter calibration  we get the small thickness. Experiments show that the detection accuracy of the system is not less than 10um.  
Research on radiometric calibration of interline transfer CCD camera based on TDI working mode (EI CONFERENCE) 会议论文  OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者:  Liu J.-G.;  Wu X.-X.
收藏  |  浏览/下载：24/0  |  提交时间：2013/03/25
Interline transfer CCD camera can be designed to work in time delay and integration mode similar to TDI CCD to obtain higher responsivity and spatial resolution under poor illumination condition. However it was found that outputs of some pixels were much lower than others' as interline transfer CCD camera work in TDI mode in laboratory radiometric calibration experiments. As a result photo response non-uniformity(PRNU) and signal noise ratio(SNR) of the system turned for the worse. This phenomenon's mechanism was analyzed and improved PRNU and SNR algorithms of interline transfer CCD camera were advanced to solve this problem. In this way TDI stage was used as a variant in PRNU and SNR algorithms and system performance was improved observably with few influences on use. In validation experiments the improved algorithms was applied in radiometric calibration of a camera with KAI-0340s as detector. Results of validation experiments proved that the improved algorithms could effectively improve SNR and lower PRNU of the system. At the same time characteristic of the system could be reflected better. As working in 16 TDI stages  PRUN was reduced from 2.25% to 0.82% and SNR was improved about 2%. 2010 Copyright SPIE - The International Society for Optical Engineering.  
Research on the laboratory radiometric calibration of the thermal imager (EI CONFERENCE) 会议论文  OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者:  Wang J.;  Liu Y.;  Liu Y.;  Liu Y.;  Sun Q.
收藏  |  浏览/下载：26/0  |  提交时间：2013/03/25
The radiometric calibration of the thermal imager was investigated to build the relationship between the input radiance and the digital output to realize the temperature measurement. The radiometric calibration was implemented in the State Key Laboratory of Applied Optics. A standard black body source was served as radiation source. The response of the thermal imager to the input radiance was tested for different gains. The experimental results show that the average grey level of the output imaging is linear dependence of the input radiance. Because the radiance in the receiving wave range of the thermal imager is linear with the black body's temperature based on Planck's law of radiation  the average grey level of the output image is also linear with the black body's temperature after fitting a curve to the experiment data points. Then the relationship of the response and the gain was studied when the black body's temperature kept constant. The preliminary analysis of calibration data shows that the response of the thermal imager is linear and the average grey value of the image is directly proportion to the gain. According to the experimental results  the reference gains and the dynamic range of temperature measurement were obtained. Finally  the uncertainty influencing the calibration results was analyzed  the analysis shows the maximal uncertainty is 5.2%  which can meet the calibration requirement less than 10%. 2010 Copyright SPIE - The International Society for Optical Engineering.  
High accuracy star image locating and imaging calibration for star sensor technology (EI CONFERENCE) 会议论文  OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
作者:  Wang Y.;  Wang Y.;  Wang Y.;  Wang Y.;  Wang Y.
收藏  |  浏览/下载：21/0  |  提交时间：2013/03/25
Today aircraft attitude measurement technology plays an important role in an aircraft system because it can provide orientation for aircraft in action. Lately star sensor technology used in aircraft attitude measurement has become more and more popular because of its high accuracy  light weight  without attitude accumulation errors and other advantages. There are three main steps for star sensor to measure aircraft attitude  star image locating  star identification and attitude tracking. The latter two steps are based on the accuracy of star image locating. So it's critical to make efforts to advance the accuracy of star image locating. Some imaging errors  such as spherical aberration or coma aberration  also have negative effect on the accuracy of star image locating  of which the effect is necessarily reduced as well. At the beginning of this article  the structure of star sensor hardware is introduced. Secondly three methods for star image locating are described specifically  which are traditional centroid method  Gauss quadric fitting method and improved Gauss quadric fitting method. Subsequently an imaging calibration method is described for the purpose of reducing the effect of imaging errors. Finally the experiment shows that the accuracy of the star sensor is 2-arc-second. 2010 SPIE.