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Research on infrared dim-point target detection and tracking under sea-sky-line complex background (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者:  
Dong Y.-X.;  Zhang H.-B.;  Li Y.;  Li Y.;  Li Y.
收藏  |  浏览/下载:112/0  |  提交时间:2013/03/25
Target detection and tracking technology in infrared image is an important part of modern military defense system. Infrared dim-point targets detection and recognition under complex background is a difficulty and important strategic value and challenging research topic. The main objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and missiles. Due to the characteristics of wide field of view of vigilance system  the target is usually under the sea clutter. Detection and recognition of the target will be taken great difficulties.There are some traditional point target detection algorithms  such as adaptive background prediction detecting method. When background has dispersion-decreasing structure  the traditional target detection algorithms would be more useful. But when the background has large gray gradient  such as sea-sky-line  sea waves etc.The bigger false-alarm rate will be taken in these local area.It could not obtain satisfactory results. Because dim-point target itself does not have obvious geometry or texture feature  in our opinion  from the perspective of mathematics  the detection of dim-point targets in image is about singular function analysis.And from the perspective image processing analysis  the judgment of isolated singularity in the image is key problem. The foregoing points for dim-point targets detection  its essence is a separation of target and background of different singularity characteristics.The image from infrared sensor usually accompanied by different kinds of noise. These external noises could be caused by the complicated background or from the sensor itself. The noise might affect target detection and tracking. Therefore  the purpose of the image preprocessing is to reduce the effects from noise  also to raise the SNR of image  and to increase the contrast of target and background. According to the low sea-skimming infrared flying small target characteristics  the median filter is used to eliminate noise  improve signal-to-noise ratio  then the multi-point multi-storey vertical Sobel algorithm will be used to detect the sea-sky-line  so that we can segment sea and sky in the image. Finally using centroid tracking method to capture and trace target. This method has been successfully used to trace target under the sea-sky complex background. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
A digital image processing system based on DSP (EI CONFERENCE) 会议论文  OAI收割
2nd International Conference on Information Engineering and Computer Science, ICIECS 2010, December 25, 2010 - December 26, 2010, Wuhan, China
作者:  
收藏  |  浏览/下载:10/0  |  提交时间:2013/03/25
Application of precision harmonic gear drive in focusing mechanism of space camera (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
作者:  
Zhang X.;  Zhang X.;  Zhang X.
收藏  |  浏览/下载:27/0  |  提交时间:2013/03/25
A kind of precision harmonic gear drive in the focusing mechanism of space camera is studied  which adopt external meshing complex wave transmission mode. Wave generator is combined with an elliptic cam and a flexible bearing around it. Flexspline is a structure of single wave with the same teeth. The output shaft is supported by a single cross-roller bearing. Ball screws connected the output shaft translate the rotational motion to the linear motion  and drive the focusing mirror repeated moving along the linear guide. The output rigid wheel is connected with absolute encoder to detect displacement of focusing movement. It has the characteristics of big transmission ratio  high precision  compact structure  high efficiency and smooth running etc. According to the practical application of this harmonic gear drive in the space camera  the location relationship between the displacement of focusing structure and the focal plane movement is derived  and the system error is analyzed  its accuracy is tested with the open-loop control method. Experimental results show that transmission ratio of the instrument is 1:70  repeated positional accuracy is 2m  which meet the requirements for use. 2010 SPIE.  
Directional multiscale edge detection using the contourlet transform (EI CONFERENCE) 会议论文  OAI收割
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
作者:  
Jin L.-X.;  Han S.-L.;  Zhang R.-F.
收藏  |  浏览/下载:36/0  |  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.  
Research on the support structure of the primary mirror of large-aperture telescope (EI CONFERENCE) 会议论文  OAI收割
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Large Mirrors and Telescopes, July 8, 2007 - July 12, 2007, Chengdu, China
Yang W.; Jingxu Z.
收藏  |  浏览/下载:29/0  |  提交时间:2013/03/25
Large-aperture telescope can be used in surveying battlefield  researching landform  searching object  real-time monitoring  imaging  detecting and identifying spatial targets and so on. A large-aperture telescope for achieving high resolution power is designed to monitor spatial target and image in real time. Real-time monitoring plays an important role in military conflicts. The orbit parameter of object  quantity  geometrical shape parameter and so on can be obtained by detect spatial target. With the development of optical technology  people require larger aperture in optics-electronic (OE) system. By increasing optical aperture  the ability of collecting light and resolution power in the system can be enhanced. But the support structure of the primary mirror of large-aperture telescope will be a very difficult problem. With the increase of primary mirror aperture  the weight of the primary mirror will become larger than before. The root mean square (rms) of the primary mirror is affected by many factors  such as deadweight  deformation of heat  environment and so on. Due to the primary mirror of telescope is an important component of telescope system. By reducing the weight of primary mirror  precision of the system is ensured. During the designing phase  one can consider the supporting project of the primary mirror synthetically and analyze it roundly according to technical requirement of optical system and the effect factors. The final structural design can be reasonable. In an astronomical telescope  the surface of reflector is an important part for collecting dark radiation of celestial bodies. Its surface shape will have an effect on collecting efficiency of telescope radiant energy directly. So the rms must be very high. Optical system of large aperture  small wavelength and small focus can receive maximal light intensity. For ground-based optical astronomical telescope  the design proposed in the paper can satisfy the requirement of the possible minimum atmosphere seeing at astronomical observatory site and exert the use efficiency of the telescope adequately. So the accuracy of the traditional surface of reflector can assure that 90% of all the light energy can be focused on within the angle diameter range of the minimum atmosphere seeing  then 100% of light energy should be focused on the angle diameter range of minimum atmosphere seeing. Because the rms of mirror is very high  precise surface machining and accurate the support of mirror are very important tasks during designing and manufacturing the telescope. In the paper  various support techniques of a large-aperture telescope primary mirror are discussed and a 3.5 meter telescope system at the Starfire Optical Range (SOR) overviewed simply  which was operated by the Directed Energy Directorate of the Air Force Research Laboratory  Kirtland AFB  NM  USA from the ground-based O-E system for the observations of spatial target. We also analyze Theoretical elastic deformation of the Steward Observatory 2.3 meter mirror is analyzed.  
Research on the affect of differential-images technique to the resolution of infrared spatial camera (EI CONFERENCE) 会议论文  OAI收割
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, July 8, 2007 - July 12, 2007, Chengdu, China
Jin G.; An Y.; Qi Y.; Hu F.
收藏  |  浏览/下载:18/0  |  提交时间:2013/03/25
The optical system of infrared spatial camera adopts bigger relative aperture and bigger pixel size on focal plane element. These make the system have bulky volume and low resolution. The potential of the optical systems can not be exerted adequately. So  one method for improving resolution of infrared spatial camera based on multi-frame difference-images is introduced in the dissertation. The method uses more than one detectors to acquire several difference images  and then reconstructs a new high-resolution image from these images through the relationship of pixel grey value. The technique of difference-images that uses more than two detectors is researched  and it can improve the resolution 2.5 times in theory. The relationship of pixel grey value between low-resolution difference-images and high-resolution image is found by analyzing the energy of CCD sampling  a general relationship between the enhanced times of the resolution of the detected figure with differential method and the least count of CCD that will be used to detect figure is given. Based on the research of theory  the implementation process of utilizing difference-images technique to improve the resolution of the figure was simulated used Matlab software by taking a personality image as the object  and the software can output the result as an image. The result gotten from the works we have finished proves that the technique is available in high-resolution image reconstruction. The resolution of infrared spatial camera can be improved evidently when holding the size of optical structure or using big size detector by applying for difference image technique. So the technique has a high value in optical remote fields.  
Studies of the defect structure for Mn2+ in KTaO3 crystal from the calculation of EPR zero-field splitting 期刊论文  OAI收割
Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 2007, 卷号: 67, 期号: 3-4, 页码: 694-696
W. C. Zheng
收藏  |  浏览/下载:13/0  |  提交时间:2012/04/13
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