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The Influence of Infilling Conditions on Flaw Surface Relative Displacement Induced Cracking Behavior in Hard Rock 期刊论文 OAI收割
ROCK MECHANICS AND ROCK ENGINEERING, 2019, 期号: -, 页码: 22
作者: Pan, Peng-Zhi; Miao, Shuting; Jiang, Quan; Wu, Zhenhua; Shao, Changyue

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Infilling condition Relative displacement of flaw surfaces Cracking behaviors Digital image correlation

Space optical remote sensor of the CAE thermal control index calculation method (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Advanced Design and Manufacturing Engineering, ADME 2011, September 16, 2011 - September 18, 2011, Guangzhou, China
作者: Li L.

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The thermal control indicators CAE methods of Space optical remote sensor are analyzed in the presented work. We sat up a thermal optical analysis model for space optical remote sensor. By assuming fully covered by in-orbit temperature load and using the finite element method for thermal deformation analysis we obtained the optical remote sensor surface deformation and displacement under various thermal loading. Using ZERNIKE polynomial wave was fitted to obtain ZERNIKE polynomial coefficients which were incorporated into the optical system design. Using CODE V optical calculation software heat-ray machines under elastic deformation of the system point spread function transfer function (MTF) wave front differential (WFE) etc. were calculated. Image quality changes of remote sensors are discussed in variety assumed cases such as temperature loads of quality change. By repeated iteration critical value of temperature fields meeting the design requirements are obtained for the optical system. Optical indicators were converged to the temperature field indicator then reasonable indicators of thermal control for remote sensors were obtained. For the thermal control design this method provided a reliable basis for design. (2011) Trans Tech Publications Switzerland.

Study on sub-pixel techniques for accurate image measurement of displacement (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Advanced Measurement and Test, AMT 2011, June 24, 2011 - June 26, 2011, Nanchang, China
作者: Zhang X.; Zhang X.; Zhang X.

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The high resolving power camera was often used to improve the precision of measuring system although its price is high because the accuracy of image measure was limited by the pixel resolving ability of camera. A method of one dimension gray level quadrature sub-pixel to detect edge was presented. This method was applied to measure the displacement of measuring head on 3-coordinate measuring machine. The data of test was shown that this system can distinguish displacement 0.001mm. it is higher accuracy than pixel level. So this method is convenient and fast fit to track and measure the moving object. It is obvious that this method can save the cost of hardware.

Imaging control of airborne area CCD mapping camera (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
作者: Chen X.; Chen X.; Chen X.

收藏 | 浏览/下载：19/0 | 提交时间：2013/03/25

Digital mapping camera is an important tool for modern airborne photogrammetry. Monochromic area CCD which is full frame transfer is selected as image sensor in this paper. Electronic shutter is utilized to eliminate the opening delay of mechanical shutter which will affect the precision of exterior orientation elements acquisition. The equation for calculation displacement of principal point is proposed for TDI forward image motion compensation to compensate principal point shift. Imaging pose control system is designed in order to meet the need for airborne stereo mapping. 2011 IEEE.

Effect of gimbal point displacement on optical axis pointing precision in an image seeker (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
作者: Zhang X.; Zhang X.; Zhang X.

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A concentric glass spherical dome was usually chosen as the transparent window mounted in front of the optical lens in an image seeker. However optical ray had to change its direction when propagating through the dome due to refraction unless passing through the center of the dome which demanded gimbal point coincide with the center of the dome exactly. In fact gimbal point displacement could not be eliminating due to fabrication assembly and vibration therefore the optical axis pointing error generated. In this paper the effect of gimbal point displacement on optical axis pointing precision in an image seeker was analyzed and the theoretical expression of the optical axis pointing error was derived based on geometric optics and the error dynamics was explored by numerical. Take a visible light image seeker as a case the thickness of concentric glass spherical dome was 8mm and the inner radius was 72mm and the optical axis pointing errors varying dynamically with the look angle and the gimbal point displacement were shown in graph. When the gimbal displacement was 0.11mm the maximum optical axis pointing error was 0.054mrad that is equal to the instantaneous field of view (IFOV) corresponding to the camera system whose focal length was 120mm and pixel size was 6.5m. Furthermore with the gimbal displacement increasing the optical axis pointing error increased linearly. The analyzed results provided a theoretical basis for the displacement range which had to be limited strictly in the gimbal design process. 2011 IEEE.

Gimbal displacement error analysis on an electro-optical seeker (EI CONFERENCE) 会议论文 OAI收割
Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China
作者: Zhang X.; Zhang X.; Zhang X.

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It is essential to analyze the gimbal displacement errors for a seeker due to the importance for cueing of targets and tracking for the final approach. Otherwise for a seeker electro-driven with a concentric glass dome the large errors will decrease the picking pointing and tracking precision rooted from the displacement errors existing between the rotation center of the optical system and the gimbal. And the gimbaled camera system displacement errors are never eliminated but reduced due to the geometric errors consists of geometric tolerances of gimbal structure manufacture installation and vibration coming from working environment. In this paper the gimbal displacement errors in an electro-optically stabilized platform resulting from geometric errors and environment errors were analyzed and shown in detail. The mathematical modal of the gimbal displacement errors created based on multi-body dynamics demonstrated the connection between the gimbal displacement errors and the stabilized platform. Taking a visible light image seeker as a case the diameter is 120mm and the geometric tolerances came from the values of primary design and the vibration data came from the environmental vibration test on the pitch-yaw seeker and at the same time the errors resulting from installation were considered too. Based on calculating the maximum gimbal displacement error will reach to 0.2mm for pitching angle smaller than 40 and yawing angle smaller than 60. However the critical parts have been found out according to the probability theory and the reliability analysis successfully used in the paper and finally the maximum gimbal displacement error reduced to 0.1mm which is acceptable corresponding to the picking pointing and tracking precision for an optical imaging seeker. 2010 Copyright SPIE - The International Society for Optical Engineering.

Research on the the device of non-angular vibration for opto-electronic platform (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Smart Structures and Materials in Manufacturing and Testing, April 26, 2010 - April 29, 2010, Dalian, China
An Y.; Song C.-P.; Kuang R.-J.; Jin G.

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The opto-electronic platform is the main equipment for aviation reconnaissance. It is a surveillance system with the function of search recognition orientation and tracking by opto- electronic instruments. It is made up of opto-electronic instruments which are used to get high quality image and stabilization tracking system to control stabilization and gesture of platform for exact tracking. The opto-electronic platform purpose is to achieve high quality image. Besides the impact of optic system the image quality of the system is influenced greatly in the vibration environment. The research worked by Zhao peng which demonstrated the affection caused by angular vibration was worse than which caused by line vibration and what was multiplied direct ratio with plane altitude. So it is necessary to design a new device which could be used widely and has good angular vibration isolation effect. According to the theory of parallelogram the non-angular vibration device had been designed with spatial links and the theory of non-angular vibration was analyzed. The three-dimensional model was set with UG the analysis was done by ADAMS/vibration software. The acceleration and displacement response of the device in each direction was calculated by inspiriting it with sine wave of the acceleration in three directions and the stiffness and damp were studied. All the work prove the design principle of the device is reasonable and the device is adopted to keep the platform motion moving horizontally at the meantime the device is good at isolating vibration in all directions. 2010 SPIE.

The movement estimation of target and background by fourier phase spectrum difference (EI CONFERENCE) 会议论文 OAI收割
2010 6th International Conference on Wireless Communications, Networking and Mobile Computing, WiCOM 2010, September 23, 2010 - September 25, 2010, Chengdu, China
作者: Zhang X.; Zhang X.; Zhang X.; Wang J.; Zhang S.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

An algorithm for estimating displacement of the moving target and background by shift theory of Fourier transform is presented. According to the relation between the change and the Fourier transform of image sequence the method employs the displacement value of the moving target and background by the difference of Fourier phase spectrum. The algorithm estimates the movements from the whole field of the image with excellent global property. This paper provides the calculus and experiments of the algorithm which show the accuracy of 1 pixel. 2010 IEEE.

Method of improving the accuracy of image motion measurement for panoramic aerial cameras (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, April 26, 2010 - April 29, 2010, Dalian, China
作者: Jia P.

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To improve the accuracy of image motion measurement for panoramic aerial cameras the paper proposed a method of real-time image motion measurement based on 2D spatial correlation. An auxiliary area CCD is positioned paralleled to the main linear TDI CCD in the focal plane of the camera. For every frame of the image sequence taken by the auxiliary CCD a prediction on the displacement of the current image in the flight direction is made based on the forward image motion velocity. The current and the reference images are combined together for 2D-correlation which products an image motion vector. By decomposing the vector both the forward and pendulum-swing image motions can be determined. The demanding computational requirements for the real-time 2D-correlation are covered by a joint transform optical correlator. Simulation test results show that the accuracy is improved and the measurement error is within 0.2 pixels for input images with SNR=1 dB. 2010 Copyright SPIE - The International Society for Optical Engineering.

Far-field focusing of laser beam based on digital image processing techniques (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China
作者: Zhao S.; Tian Y.-Z.; Liu L.-S.; Guo J.; Zhang H.-Y.

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In order to lead the laser beam transmit in the atmosphere convergently an experiment of laser focus at the distance of 450m and 300m has been operated in the outdoor place. The actual manipulations are as follows: Firstly the laser was collimated by a beam expander then the near-parallel laser beam was transmitted with a Galileo telescope system and the distance between the concave lens and the convex lens can be tuned through a precise displacement platform so the focus of the system changed due to the tiny displacement of the concave lens. Secondly the average power of the laser spot can be measured using power meter the power is 47.67mW and the standard deviation is 0.67mW while the focal length is 450m. Thirdly the energy distribution was found through the laser beam analyzer. The spot images were saved using the beam analyzer then the saved image can be processed with Matlab software afterwards. The function named EDGE and Sobel operator was used in the pre-processing of the saved image then method of median filter was used in the course of image de-noising and 53H filter was adopted in the signal analysis. The diameter of laser spot was obtained by the method above the diameter is 5.56mm and the standard deviation is 0.24mm. The spot center excursion is 0.56mm it is 10.43% of the total diameter of the laser spot. At last the key factors of the energy dissipation in the focusing system can be summarized as follows: restriction of the diffraction limit attenuation in the atmosphere geometrical aberration of optical system and the diffraction limit and the geometrical aberration are significant in the three factors above so we can reduce the impact of the both factors during the design of optical system. The reliable referenced data of the system design can be acquired through the primary experiment research. 2010 SPIE.