中国科学院机构知识库网格系统: 检索

Optical design of off-axis astronomical space telescope based on freeform surfaces 会议论文 OAI收割
International Optical Design Conference 2014, IODC 2014, June 23, 2014 - June 26, 2014, Kohala Coast, HI, United states
作者: Wu H.-B.; Wang C.; Wu Y.-X.; Shi G.-W.; Zhang J.-P.

收藏 | 浏览/下载：26/0 | 提交时间：2015/04/27

Simulation test research of using the Ritchey-Common method for the detection of large flat mirror (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Frontiers of Advanced Materials and Engineering Technology, FAMET 2012, January 4, 2012 - January 5, 2012, Xiamen, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：11/0 | 提交时间：2013/03/25

In the detection of large flat mirror the Ritchey-Common test can achieve high accuracy measurement. A method which expands the compressed images due to Ritchey Angle and rotates the plane under test is presented achieve two sets of influence functions through this we can built two equations according to two different angular positions we can solve the equations by least squares method. Then through fitting the coefficients we can get the flat errors this paper describe the simulation test of the method in order to prove the feasibility and reliability of this method. (2012) Trans Tech Publications.

The design of computer-generated holograms for testing unsymmetrical optical surfaces (EI CONFERENCE) 会议论文 OAI收割
2012 International Symposium on Photonics and Optoelectronics, SOPO 2012, May 21, 2012 - May 23, 2012, Shanghai, China
作者: Zhang X.; Zhang Y.; Zhang X.; Zhang X.

收藏 | 浏览/下载：15/0 | 提交时间：2013/03/25

It is a technical difficulty to test the unsymmtrical optical surfaces in non-contact methods. But we can do it using computer-generated holograms (CGH). The principle and design of the CGH have been discussed in the paper. Take the cubic suface as an example The order separation of the CGH is analyzed theoretically and the simulation result of the order separation is given in the paper. We develop the binary process of the continuous CGH phase function and get the sample of the amplitude CGH. A CGH for testing a cubic phase plate with duty cycle 0.5 is fabricated by using e-beam lithographic techniques. In this situation the contrast of the interference fringe pattern can achieve a level of 99.4% by calculation. 2012 IEEE.

Simulation test research of using the Ritchey-Common method for the detection of large flat mirror 会议论文 OAI收割
2012
Zhu S.; Zhang X. H.

收藏 | 浏览/下载：3/0 | 提交时间：2013/03/28

The optical design of cubic phase plate testing system (EI CONFERENCE) 会议论文 OAI收割
2011 Symposium on Photonics and Optoelectronics, SOPO 2011, May 16, 2011 - May 18, 2011, Wuhan, China
作者: Zhang X.; Zhang X.; Zhang X.; Zhang Y.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Computer-generated holograms (CGH) have been widely used for years in optical testing of aspheric surfaces in combination with Fizeau interferometers. With the development of diffraction optics computer technology and micro-processing technology the accuracy of the CGH testing can achieve a hundredth of a wave and the cost is reduced greatly. CGH is capable of producing an optical wavefront with any desired shape. So it is fascinating and will have good prospects to test free-form surfaces using CGH. As the CGH can create any wavefront shape it can also be used in unsymmetrical aspherical surfaces testing. Taking the cubic surface as an example this paper gives a method to test unsymmetrical surfaces. This paper gives the design to test a cubic surface. And the separation of the diffraction orders and the binary process of the continuous CGH phase function are discussed in detail. The alignment tolerance of the test system and the CGH fabrication tolerance are analyzed. We also present an idea using a CGH and two spherical lenses as null lens to test the cubic surface when the surface deviation is great. 2011 IEEE.

Correction of the non-uniformity for multi-TDICCD mosaic camera on FPGA (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on E-Product E-Service and E-Entertainment, ICEEE2010, November 7, 2010 - November 9, 2010, Henan, China
Zhu H.; Xue X.; Ma T.; Li H.; Si G.; Guo Y.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

To solve the non-uniformity problem of multi Time Delay Integral Charge Couple Device (TDICCD) mosaic camera several common non-uniformity correction methods are discussed. Secondly a non-uniformity correction algorithm is proposed and implemented on Field-Programmable Gate Array (FPGA) platform. Firstly the correction algorithm is designed. Finally the generation and definition of non-uniformity are introduced considering the fix-point processing ability of FPGA the correction algorithm is optimized properly and implemented on FPGA. The experimental results indicate that the non-uniformity can be decreased from 8.3%to 2.0% in 1s for 3-TDICCD mosaic camera's images with the proposed correction algorithm at 96TDI stage proving that this correction algorithm is of high real-time performance good practicality and satisfies the requirements of the target system. 2010 IEEE.

Design of Wide Stop-Band and Narrow Pass-Band Filters 会议论文 OAI收割
2010
作者: Chen X.; Chen X.; Chen X.

收藏 | 浏览/下载：7/0 | 提交时间：2013/03/28

A Novel Element of Frequency Selective Surfaces for Stealth Radome 会议论文 OAI收割
2010
作者: Chen X.; Chen X.; Chen X.

收藏 | 浏览/下载：11/0 | 提交时间：2013/03/28

Research of improving the accuracy of license plate character segmentation (EI CONFERENCE) 会议论文 OAI收割
5th International Conference on Frontier of Computer Science and Technology, FCST 2010, August 18, 2010 - August 22, 2010, Changchun, China
作者: Zhu Y.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

In order to improve the accuracy of license plate character segmentation use line-shape filter to remove plate frames. Then character segmentation approach combines projection and inherent characteristics of character this paper strengthens preprocessings before segmentation. In character binarization can better solve character adhesion and fracture problem. For tilted characters only in horizontal direction use improved Bemsen method to reduce noise interference even without tilt correction this method can achieve better segmentation. Experiment results shows the accuarcy of character segmentation reaches 97%. 2010 IEEE.

1D-KBA microscope using double-periodic multilayer (EI CONFERENCE) 会议论文 OAI收割
Advances in X-Ray/EUV Optics and Components IV, August 3, 2009 - August 5, 2009, San Diego, CA, United states
作者: Wang Z.; Wang X.; Wang X.; Wang X.; Wang Z.

收藏 | 浏览/下载：9/0 | 提交时间：2013/03/25

To study the action of shock wave in CH target one-dimensional grazing incidence KBA microscope for 4.75keV energy was set up. Because of strong absorption in air 4.75keV energy microscope can just work in vacuum. Accordingly the alignment and assemblage will be very complicated and difficult. A special multilayer method using double periodic multilayer was proposed to solve this problem. This multilayer has high reflectivity not only for 4.75keV X-rays but also for 8keV X-rays at the same grazing incidence angle. It means 1D-KBA microscope has the same light trace for different working energies. Therefore we can implement the alignment and assembly of 4.75keV system by the help of 8keV X-rays. Because 8keV X-rays is very easy produced by X-ray tube and has strong transmittability in air the alignment and assemblage process became relatively easy. By now we have finished the alignment experiment at 8keV and obtained imaging results. The performance is about 2-3m resolution in 250m field of view. It is coincide with the calculation. 2009 SPIE.