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	Binary systems at and beyond the short-period limit of WUMa systems 会议论文 OAI收割 Workshop on Observing Techniques, Instrumentation and Science for Metre-Class Telescopes, Stara Lesna, SLOVAKIA, 2013-09-23 作者: Qian SB(钱声帮); Jiang LQ(江林巧); Zhu LY(朱俐颖); Zejda, M; Mikulasek, Z 收藏 \| 浏览/下载：27/0 \| 提交时间：2016/04/08 Stars: binaries : close Stars: binaries : eclipsing Stars: low-mass
	A hybrid median filter for enhancing dim small point targets and its fast implementation (EI CONFERENCE) 会议论文 OAI收割 2011 International Conference on Multimedia and Signal Processing, CMSP 2011, May 14, 2011 - May 15, 2011, Guilin, Guangxi, China Yang Q. 收藏 \| 浏览/下载：17/0 \| 提交时间：2013/03/25 Weak stars and middle altitude orbit satellites or high altitude orbit satellites are presented as dim point targets in images of astronomical observation. They have low intensity and occupy few pixels in image. In most situations the background of sky is always ununiform and there exists pulse noises. Thus results in targets submerging in background noises and low signal noise ratio (SNR). Median filter is an effective method for removing pulse noise. But it can blur image after modifying gray of non-noise pixels when image has low SNR. A hybrid median filter algorithm is proposed to process low SNR dim point targets image. The newly proposed method can suppress the pulse noises also can increase target $SNR$ and does not add extra fake targets. The time complexity of median filter is O(N2)(N is the widow size) and is difficult to implement in hardware. For quasi real time application a fast implementation of our hybrid median filter is proposed to reduce the time complexity to O(N). Experimental results show that the newly proposed algorithm is superior to ordinary median filter and fast median filter by comparing visual effect and performance. 2011 IEEE.
	An improved two-dimensional entropy method for star trail tracing in deep sky (EI CONFERENCE) 会议论文 OAI收割 ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China 作者: Wang Y.-J.; Yao Z.-J. 收藏 \| 浏览/下载：15/0 \| 提交时间：2013/03/25 The trace of star trail is an important component of deep sky detection. The stars are low contrast targets and their self-rotation will make their brightness change in cycle. Above all the trail trace is vulnerable to the block and disturbance of other stars. Traditional one-dimensional maximum entropy thresholding algorithm is vulnerable to the noise and the calculation of two-dimensional entropy methods is too large and takes too much time. This paper proposes an improved two-dimensional entropy threshold algorithm. We use recursion iteration method to eliminate the redundancy calculation and reduce the size of two-dimensional histogram based on the deep sky stars characteristic such as low contrast fuzziness and the centralized histogram. We also combine our algorithm with the space trail trace model to forecast the star trace. Experiments results show when the star are blocked or they turn dark the method still can well extrapolate the star trace. Our method improves the capability of trailing the ebb and small star and increases the precision of tracing. It is also robust to the noise so there is a good application foreground for the method.
	A deep-space trail forecast method based on the enlargement of field of view (EI CONFERENCE) 会议论文 OAI收割 16th International Conference on Artificial Reality and Telexistence - Workshops, ICAT 2006, November 29, 2006 - December 1, 2006, Hangzhou, China Han Q.; Yao Z.; Zhu M. 收藏 \| 浏览/下载：14/0 \| 提交时间：2013/03/25 During the procedure of target tracing lots of stars will cross the field of view. These stars will disturb the procedure and the precision of system will be degraded. At the same time because the optical surveillance system is limited by environment the targets are often covered by clouds. The above situations will seriously degrade the system's robustness and once the target is disappeared the traditional system can't track the target again. Traditional forecast methods merely use coder information so the precision is low. In order to upgrade the precision we combine the coder information and the missdistance to forecast the next frame target position. The method is based on field range enlargement. Proved by practical experiments this method can effectively improve the robustness of the target tracking system. 2006 IEEE.
	CMOS APS imaging system application in star tracker (EI CONFERENCE) 会议论文 OAI收割 Advanced Materials and Devices for Sensing and Imaging II, November 8, 2004 - November 10, 2004, Beijing, China 作者: Li J.; Liu Y.; Liu Y.; Liu Y.; Liu J. 收藏 \| 浏览/下载：52/0 \| 提交时间：2013/03/25 Small satellites are capable of performing space explore missions that require accurate attitude determination and control. However low weight size power and cost requirements limit the types of attitude sensor of small craft such as CCD are not practical for small satellites. CMOS APS is a good substitute for attitude sensors of small craft. Some of the technical advantages of CMOS APS are no blooming single power low power consumption small size and little support circuitry direct digital output simple to system design in particular radiation-hard characteristic compare with CCD. This paper discusses the application probability of CMOS APS in star tracker for small satellites further more a prototype ground-based star camera based on STAR250 CMOS image sensor has been built. In order to extract stars positions coordinates subpixel accuracy centroiding algorithm has been developed and tested on some ground-based images. Moreover the camera system star sensitivity and noise model are analyzed and the system accuracy is been evaluated. Experimental results indicate that a star camera based on CMOS APS is a viable practical attitude sensor appropriate for space small satellites.