中国开放科研知识云: 检索

Analysis of power spectral density as a performance metric for TMT M3 会议论文
7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, AOMATT 2014, April 26, 2014 - April 29, 2014, Harbin, China
Yang F.; An Q.-C.; Wang F.-G.; Liu X.-Y.

收藏 | 浏览/下载：14/0 | 提交时间：2015/04/27

A novel Design measuring Method based on linearly polarized laser interference 会议论文
5th International Symposium on Photoelectronic Detection and Imaging, ISPDI 2013, June 25, 2013 - June 27, 2013, Beijing, China, June 25, 2013 - June 27, 2013
Cao Y.; Ai H.; Zhao N.

收藏 | 浏览/下载：8/0 | 提交时间：2014/05/15

Data processing method of multi-position strap-down north seeking system based on SVD (EI CONFERENCE) 会议论文
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
Shen C.-W.; Liu C.; Yu S.-B.; Wang Z.-Q.; Li J.-R.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

With the aim to fit the sin wave curve of a multi-position strap-down north seeking system and to calculate the real north angle accurately the principles of the system and the algorithm of singular value decomposition(SVD) are introduced. The factors influencing the measuring precision are also analyzed. Then the algorithm is adopted to fit curves. Experimental results indicate that the singular value decomposition is very precise for its error sum is 1.1102V and the squared error is 2.8mV. Moreover for phase angle measurement measured six times in same direction the squared error is 24 (1). The method based on SVD can satisfy the system precision requirements of curve-fitting north seeking systems. 2011 IEEE.

The Research of real time auto-recognition of the moire fringe (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Wang M.-J.; Wu Z.-G.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

Measuring the movement of raster by the method of moire fringe has the advantage of high sensitivity high resolution and non-contacted measurement. The characteristic of moire fringe is that the image is white alternate with black the angle of the stripes is uniform the width of the stripes is uniform the terminators of the stripes aren't clear. A fast method that can figure out the width and angle of the moire fringe precisely is put forward in this paper. It calculates the angle the stripes firstly. According to the principle of the minimum mean squared error (MMSE) the closer a series of data is the smaller the value of the MMSE will be. The method is described as follows: It takes the image's center as the origin 180 beelines pass through the origin with the same angle interval. it calculates the value of the minimum mean squared error of the 180 beelines and find out the least one among those then the angle of the moire fringe comes out primarily. In order to improving the calculating precision of moire fringe 60 equal angles are divided in the neighborhood of the angle then a precise angle of moire fringe is calculated according to the principle of the MMSE. After getting out the angle of the moire fringe we begin to calculate the width of moire fringe. A line vertical with the moire fringe is drawn and we can get the width of the moire fringe by the vertical line. In order to get over the influence of the noise an effective area with the shape of diamond is selected in the image. The data of area is accumulated and projected according to the direction of moire fringe and a sine curve come out. The width of moire fringe can be obtained by getting the position of the first wave crest the position of the last wave crest and the number of wave crest. Experiments prove that the precision of the method put forward in this paper is enhanced in comparison with the traditional frequency method the precision of width calculation achieves to 99.6% according to the evaluation indicators of width detection error. The computing speed is boosted largely compared with traditional method and it can achieve with 15 ms that satisfying the demand of real time. 2011 SPIE.

Research on the laboratory radiometric calibration of the thermal imager (EI CONFERENCE) 会议论文
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
Lu Z.; Sun Q.; Wang J.; Lu Z.; Liu Y.

收藏 | 浏览/下载：17/0 | 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.

Research on automatic Hartmann test of membrane mirror (EI CONFERENCE) 会议论文
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
Zhong X.; Jin G.; Liu C.; Zhang P.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

Electrostatic membrane mirror is ultra-lightweight and easy to acquire a large diameter comparing with traditional optical elements so its development and usage is the trend of future large mirrors. In order to research the control method of the static stretching membrane mirror the surface configuration must be tested. However membrane mirror's shape is always changed by variable voltages on the electrodes and the optical properties of membrane materials using in our experiment are poor so it is difficult to test membrane mirror by interferometer and null compensator method. To solve this problem an automatic optical test procedure for membrane mirror is designed based on Hartmann screen method. The optical path includes point light source CCD camera splitter and diffuse transmittance screen. The spots' positions on the diffuse transmittance screen are pictured by CCD camera connected with computer and image segmentation and centroid solving is auto processed. The CCD camera's lens distortion is measured and fixing coefficients are given to eliminate the spots' positions recording error caused by lens distortion. To process the low sampling Hartmann test results Zernike polynomial fitting method is applied to smooth the wave front. So low frequency error of the membrane mirror can be measured then. Errors affecting the test accuracy are also analyzed in this paper. The method proposed in this paper provides a reference for surface shape detection in membrane mirror research. 2010 Copyright SPIE - The International Society for Optical Engineering.