中国开放科研知识云: 检索

Pre-process technique study of a high performance remote image sensor structural Finite Element Analysis (EI CONFERENCE) 会议论文
2010 2nd International Conference on Computer Engineering and Technology, ICCET 2010, April 16, 2010 - April 18, 2010, Chengdu, China
Li H.-X.; Ding Y.-L.; Zhang L.; Xu Y.-S.

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High precision structural Finite Element Analysis (FEA) results are required in the development of a remote image sensor. HperMesh and MSC. Nastran are employed in the image sensor structural FEA. This paper discusses some technical issues about the Finite Element (FE) modeling of the image sensor. In order to obtain authentic analysis results the part-to-whole handling schema i.e. handling method and research work is implemented in a small part of the model firstly and a revised method is used in the whole structural in succession has been proposed. Some emphasis is mainly put on the FE handling of bolted joint bearing and inter-element connection. The interface handling methods such as CBEAM plus partial MPC bolted joint model hybrid element bearing model and RBE3 beam-to-solid connection have been produced and successfully implemented in the image sensor structural FEA. 2010 IEEE.

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

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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.

A local feature based simplification method for animated mesh sequence (EI CONFERENCE) 会议论文
2010 2nd International Conference on Computer Engineering and Technology, ICCET 2010, April 16, 2010 - April 18, 2010, Chengdu, China
Zhang S.; Zhao J.; Wang B.

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Although animated meshes are frequently used in numerous domains only few works have been proposed until now for simplifying such data. In this paper we propose a new method for generating progressive animated models based on local feature analysis and deformation area preservation. We propose the use of solid angle and height value for a non-hyperbolic vertex to define the local feature parameter. This local factor is embedded to the vertex quadric error matrix when calculating the edge collapse cost. In order to preserve the areas with large deformation we add deformation degree weight to the aggregated quadric errors when computing the unified edge contraction sequence. Finally a mesh optimization process is proposed to further reduce the geometric distortion for each frame. Our approach is fast easy to implement and as a result good quality dynamic approximations with well-preserved fine details can be generated at any given frame. 2010 IEEE.

Infrared signature measurement of targets accounting for atmospheric attenuation (EI CONFERENCE) 会议论文
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Yang C.-Y.; Cao L.-H.; Zhang J.-P.; Lu M.

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Infrared radiation signature measurement of targets is one of important ways for target signature acquirement and target recognition. When measuring the infrared signature of a target in the atmosphere molecules and aerosol particles in the atmosphere would attenuate the infrared radiation from the target and at the same time the air path radiation would be added to the target radiation. Therefore in order to obtain the intrinsic infrared radiation of the target it is necessary to perform atmospheric correction in the process of target radiation inversion. A model for target radiation measurement and inversion was established and precision analysis on the model was given. A longwave infrared camera was used to perform infrared signature measurement experiment on an ISDC extended-area blackbody. Based on atmospheric parameters the atmospheric transmittance and the air path radiation between the blackbody target and the camera were calculated by using the MODTRAN software for use in atmospheric correction in the target radiation inversion process. The experimental results showed that radiation inversion precisions were about 7.3%9.3%. Additionally inversion precision will improve as target temperature rises. 2010 IEEE.

Analysis of measuring errors for the visible light phase-shifting point diffraction interferometer (EI CONFERENCE) 会议论文
2010 OSA-IEEE-COS Advances in Optoelectronics and Micro/Nano-Optics, AOM 2010, December 3, 2010 - December 6, 2010, Guangzhou, China
Zhang Y.; Jin C.; Lu Z.

收藏 | 浏览/下载：10/0 | 提交时间：2013/03/25

In order to improve the measuring accuracy of the visible light phase-shifting point diffraction interferometer (PS/PDI) for the extreme ultraviolet lithography (EUVL) aspheric mirrors the main measuring errors will be discussed in this paper. At first the elementary configuration and measuring principle of the visible light phase-shifting point diffraction interferometer are introduced briefly then the different errors which are possible to affect the measuring result are summed up the errors include PZT phase-shifting error detector nonlinearity error detector quantization error wavelength instability error and intensity instability error of the laser source vibration error air refractivity instability error and so on. Through detailed analysis and simulation the magnitude of these errors can be obtained. By analysing the reasons which cause these errors and the relationship between these errors and interferometer configuration parameters some methods are put forward to avoid or restrain these errors accordingly.

Optimal design of strap-down inertial navigation support under random loads (EI CONFERENCE) 会议论文
2010 IEEE International Conference on Information and Automation, ICIA 2010, June 20, 2010 - June 23, 2010, Harbin, Heilongjiang, China
Hao X.; Li M.; Jia H.; Xuan M.

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In order to realize miniaturization and light weight of the strap-down inertial navigation system and then to make sure that it works well under random loads optimal design is applied to the strap-down inertial navigation support with the methods of topology optimization and size optimization. Firstly based on the installation requirement of devices and connection requirement of the support and the carrier the initial structure of the support is designed. Topology optimization with FEA software ANSYS is adopted on the initial structure to get the basic one. Then 5 critical sizes are chosen as design variables and the support structure is optimized by means of size optimization to reach light weight with satisfying the requirement of dynamic stiffness. Finally random vibration analysis is applied to the initial structure. In the mean time random vibration test is carried out to qualify the analysis method. After the qualification a random vibration analysis is applied to the optimized support structure to get the rms of displacement response and acceleration response of the support to validate whether the optimized structure is appropriate. The results indicate that the dynamic stiffness of the optimized support structure satisfies the design requirements and its weight is lighter 49.38% than that of the initial one. This research can be a reference to the structure design of supports under random loads and the result has been applied to the development and manufacture of a prototype aerocraft. 2010 IEEE.

Influence of spatial temperature distribution on high accuracy interferometric metrology (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
Gu Y.; Miao E.; Yan F.; Zhang J.; Yang H.

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We calculate the influence of temperature change on the refractive index of air establish a model of air temperature distribution and analyze the effect of different temperature distribution on the high accuracy interferometric metrology. First a revised Edlen formula is employed to acquire the relation between temperature and refractive index of air followed by introducing the fixed temperature gradient distribution among the spatial grid within the optical cavity between the reference flat and the test flat of the Fizeau interferometer accompanied by a temperature change random function within each grid. Finally all the rays through the air layer with different incident angles are traced by Matlab program in order to obtain the final output position angle and OPD for each ray. The influence of different temperature distribution and the length of the optical cavity in on the testing accuracy can be analyzed through the RMS value that results from repeatable rays tracing. As a result the horizontal distribution (vertical to optical axis) has a large effect on the testing accuracy. Thus to realize the high accuracy figure metrology the horizontal distribution of temperature must be rigorously controlled as well as to shorten the length of the optical cavity to a large extent. The results from our simulation are of great significant for the accuracy analysis of interferometric testing and the research of manufacturing a interferometer. 2010 Copyright SPIE - The International Society for Optical Engineering.

Design and analysis of power system of micro-electromechanical actuator (EI CONFERENCE) 会议论文
2010 2nd International Conference on Industrial Mechatronics and Automation, ICIMA 2010, May 30, 2010 - May 31, 2010, Wuhan, China
Han X.; Liu B.; Zhang J.; Jia H.; Ge W.

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In order to apply the electromechanical actuator to tactical mini-missiles maximum rotational speed of output shafts is greater than 250/s. Test results basically correspond to the requirement of technical indexes. It is proved that this analysis and design method is congruent with the design of micro-electromechanical actuators this paper researches on the key technology such as load-bearing ability the system bandwidth can reach 25.3Hz on the condition of no load and 23.4Hz on the condition of load thus the method is feasible. 2010 IEEE. rapidity and miniaturization of the micro-electromechanical actuator power system based on the ball screw. First according to specific technical indexes the power electromechanical time constant and the size of the motors are screened originally through theoretical analysis. Finally based on the characteristics of ball screw transmission load locus of the micro-electromechanical actuator dynamic system is theoretically analyzed and the optimum speed ratio is determined through parameter optimization. The results of the double closed loop controlled test on the principle prototype show: the system can operate normally with 2.5N.m hinge moment

Electromagnetic radiation test of power driver module in optical tracking system and electromagnetic compatibility (EI CONFERENCE) 会议论文
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Ge X.; Guo L.; Meng F.; Sun S.; Yu H.

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In order to solve the conductive ring module's interference problems measured the electromagnetic radiation of Power drive module and used test results analysis the electromagnetic compatibility of the conductive ring identified and implemented appropriate EMC (electromagnetic compatibility) measures. When optical tracking system working test equipment can not be fixed. Therefore from the electromagnetic radiation theory the paper analyzed the electromagnetic radiation of the power drive module. From it determine the EMC pre-compliance test method for electromagnetic radiation of power drive module. Based on Test results calculate the interference voltage of wire in Conductive ring and then determine the corresponding EMC method. The results show that when The power drive module Radiate Electromagnetic waves wires would coupled common mode interference voltage its frequency is 3MHz amplitude is about 10V it would interfered the operation of sensor. By reducing the area of ground loops used shielded cables final rule out the interference. 2010 IEEE.

Directional multiscale edge detection using the contourlet transform (EI CONFERENCE) 会议论文
2010 IEEE International Conference on Advanced Computer Control, ICACC 2010, March 27, 2010 - March 29, 2010, 445 Hoes Lane - P.O.Box 1331, Piscataway, NJ 08855-1331, United States
Ma S.-F.; Zheng G.-F.; Jin L.-X.; Han S.-L.; Zhang R.-F.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

Wavelet multiresolution analysis allows us to detect edges at different scales also to obtain other important aspects of the extracted edges. However due to the usual two-dimensional tensor product wavelet transform is not optimal for representing images. The main problem in edge detection using wavelet transform is that it can only capture point-singularities and the extracted edges are not continuous. In order to solve that problem we propose a new image edge detection method based on the contourlet transform. The directional multiresolution representation Contourlet takes advantages of the intrinsic geometrical structure of images and is appropriate for the analysis of the image edges. Using the modulus maxima detection an image edge detection method based on contourlet transform is proposed. To suppress the image noise effect on edge detection the scale multiplication in contourlet domain is also proposed. Through real images experiments the proposed edge detection method's performance for the extracted edges is analyzed and compared with other two edge detection methods. The experiment result proves that the proposed edge detection method improves over wavelet-based techniques and Canny detector and also works well for noisy images. 2010 IEEE.

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