中国科学院机构知识库网格系统: 检索

Self-adaptive echo signal processing method for pulse radar ranging system 会议论文 OAI收割
2016 IEEE Information Technology, Networking, Electronic and Automation Control Conference, ITNEC 2016, Chongqing, China, May 20-22, 2016
作者: Gao J(高洁); Du JS(杜劲松); Bi X(毕欣)

收藏 | 浏览/下载：45/0 | 提交时间：2016/11/01

time-of-flight Pulse radar characteristic values Parabola fitting the least-squares method

A sub-pixel extraction method for the center of the circular structure from spot array calibration target (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Information Technology for Manufacturing Systems, ITMS 2012, September 8, 2012 - September 9, 2012, Qingdao, China
作者: Liu Y.; Zhang T.; Yang H.; Gao X.; Liu Y.

收藏 | 浏览/下载：75/0 | 提交时间：2013/03/25

The imaging measurement system must be calibrated before application. In calibration procedure sub-pixel center extraction is the crucial step for the final accuracy. In this paper a new sub-pixel extraction method is proposed. Edge detection at pixel level is obtained using LOG operator then sub-pixel edge detection is realized using the Facet model. Finally the least squares ellipse fitting is operated on the sub-pixel edge to determine the sub-pixel center. Experiment on a series of simulated images indicates that this algorithm is able to realize the center location accuracy of 0.01-0.02 pixel and meets the requirement of sub-pixel level. (2012) Trans Tech Publications Switzerland.

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：16/0 | 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.

Image registration based on Mexican-hat wavelets and pseudo-Zernike moments (EI CONFERENCE) 会议论文 OAI收割
2012 World Automation Congress, WAC 2012, June 24, 2012 - June 28, 2012, Puerto Vallarta, Mexico
作者: Liu Y.; Liu Y.; Liu Y.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

Image registration is a key technique in pattern recognition and image processing and it is widely used in many application areas such as computer vision remote sensing image fusion and object tracking. A method for image registration combining Mexican-hat wavelets and pseudo-Zernike moments is proposed. Firstly feature points are extracted using scale-interaction Mexican-hat wavelets in the reference image and sensed image respectively. Then pseudo-Zernike moments are used to match them and classical RANSAC used to eliminate the wrong matches. And then the well match points are used to estimate the best affine transform parameters by least squares minimization. At last the sensed image is transformed and resampled to accomplish the image registration. The experiments indicate that the proposed algorithm extracts feature points and matches them exactly and eliminates wrong matched points effectively and achieves nice registration results. 2012 TSI Press.

Application of trend extrapolation method to spectrum analysis of microtremor signal (EI CONFERENCE) 会议论文 OAI收割
2nd World Congress on Computer Science and Information Engineering, CSIE 2011, June 17, 2011 - June 19, 2011, Changchun, China
Zhou X.; Guo T.; Jiao J.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

The trend extrapolation method is applied to spectrum analysis of microtremor signal in order to increase the spectral estimation accuracy. First establish an appropriate extrapolation model based on the existing data series and then fit correlation functions other than existing data by derivative least squares method finally perform spectrum analysis using extrapolated correlation functions. Numerical simulations and the experimental results show that good results are achieved no matter correlation functions change slow or rapid and the extrapolation error is not more than 2.3%. 2012 Springer-Verlag Berlin Heidelberg.

Research on image restoration of Roll-Swing imaging seeker (EI CONFERENCE) 会议论文 OAI收割
3rd IEEE International Conference on Advanced Computer Control, ICACC 2011, January 18, 2011 - January 20, 2011, Harbin, China
作者: Zhang H.; Zhang H.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

To achieve a correct image receiving for Roll-Swing imaging seeker the mechanism and imaging process is analyzed. The causes of image rotation are discussed. The influence of the frame encoders' precision on imaging de-rotation quality is analyzed. The Roll-Swing imaging seeker is designed for high-speed aerocraft thus the received images are greatly degraded due to atmospheric turbulence. A new method of image restoration is proposed for turbulence-degraded images in this paper. The method is to get point spread function (PSF) based on the estimation of optical transfer function (OTF) according to the optical system design simulation. Finally to obtain the restored image constrained least squares filtering is used with the known PSF. The experiment results indicate that the new restoration method has a favorable effect to satisfy requirement of the automatic target recognition. 2011 IEEE.

Accuracy analysis and optimization design of constant-diameter cam (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
Yuan G.-Q.; Ding Y.-L.; Hui S.-W.; Liu Z.-H.; Li Y.-W.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

A constant-diameter cam gets its name because the centers of the rollers are a constant distance apart. This paper presents an Accuracy analysis and optimization design method for constant-diameter cam mechanism. Factors affecting the accuracy of cam are studied in the paper. The influences of the roller radial runout cam machining error and the base circle radius on accuracy are analyzed. Then a method to guarantee the cam diameter constant and remove return stroke error is studied using least-squares method. The analysis results indicate that the focusing accuracy can reach 4.4m and the return stroke error can reach 4.8m the functioning of institutions is stable and reliable. 2011 IEEE.

Design of aspherical surfaces for panoramic imagers using multipopulations genetic algorithm (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Jin C.-S.; Wang L.-P.; Liang Z.-Z.

收藏 | 浏览/下载：30/0 | 提交时间：2013/03/25

A design method of aspherical surface for panoramic imaging system with two mirrors using multi-populations genetic algorithms is proposed. Astigmatism induced by mirrors may significantly compromise image resolution. To solve this problem we induced algebraic expression of astigmatism in panoramic imager based on generalized Coddington equation and theory of geometric optics. Then we propose an optimization process for mirror profile design to eliminate astigmatism and provide purposely-designed projection formula with aid of MPGA. A series of polynomial expressions of aspherical surfaces are obtained and procedures of the design are presented. In order to facilitate ray tracing and aberration calculation even asphere surface model is obtained by using of hybrid schemes combining MPGA and damped least squares. Finally a prototype of the catadioptric panoramic imager has been developed and panoramic ring image is obtained. 2009 SPIE.

Configuring an electrostatic membrane reflector with potentials exerted on distributed electrodes (EI CONFERENCE) 会议论文 OAI收割
2009 IEEE International Conference on Mechatronics and Automation, ICMA 2009, August 9, 2009 - August 12, 2009, Changchun, China
作者: Zhang P.; Shi G.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Electrostatic membrane reflector (EMR) is very promised for optical quality application with the merits of utra-lightweight and flexible. Configuring a circular membrane reflector with electrostatic potentials exerted on distributed electrodes can approximatively produce a parabolic shape. A 300mm EMR (made from polyimide) stretched by distributed electrodes below is designed and the number of concentric electrodes needed for membrane shape forming is analysed. First based on an analytical solution of Poisson's equation determine the membrane control matrix by finding influence functions of 3 concentric electrodes and 6 control points on membrane surface in order to compute the needed voltages exerted on the distributed electrodes by the method of least-squares fitting. Then the final shape solved by finite element analysis with ANSYS is contrasted with the paraboloid and deviates greatly when the central displacement of membrane is beyond 2.5mm but in this range increasing the number of electrodes and control points will get a better shape. The corresponding errors are analyzed and the control method is concluded. Only using the integrated method of analytical computation numerical analysis and experiment the membrane shape of certain central displacement can be exactly predicted and controlled. 2009 IEEE.

Test of an off-axis asphere by subaperture stitching interferometry (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Zheng L.-G.; Zhang X.-J.

收藏 | 浏览/下载：54/0 | 提交时间：2013/03/25

A new method combined subaperture stitching with interferometry(SSI) is introduced. It can test large and off-axis aspheric surfaces without the aid of other null optics. In this paper the basic principle and theory of the technique are analyzed. The synthetical optimization stitching model and effective stitching algorithm are established based on homogeneous coordinates transformation and simultaneous least-squares method. The software of SSI is devised and the prototype for testing of large aspheres by SSI is designed and developed. An off-axis asphere with the aperture of 376mm188mm is tested by this method. For comparison and validation and the difference of PV and RMS error between them is 0.047 e and 0.006 e the asphere is also tested by null compensation.The synthesized surface profile is consistent to that ofthe entire surface from null test respectively. So it provides another quantitative measurement for testing large aspheric surfaces and off-axis aspheres besides null-compensation. 2009 SPIE.