一种CCD星图星点快速定位算法

大尺寸CCD星图快速处理是制约天基光学观测器件性能的关键因素之一,在星敏感器、空间监视载荷等研制中具有重要意义.通过对CCD星图图像特点的分析,提出了以最大概率实现背景噪声滤除的星图预处理准则;在此基础上,提出了通过两次投影检测实现星点位置测量的算法.与传统方法相比,该算法实现简单,节约了计算量和存储量.对分辨率为2048×2048的CCD实拍星图的实验研究表明了该算法的有效性. 

Algorithm for CCD Star Image Rapid Locating

Rapid processing of large scale CCD star image is a key technique for new type of star sensor as well as space surveillance sensor. The foreground of CCD star image is differ form the background distinctly. Majority pixels of the image belong of the background. The typical histogram of CCD star image has a two-peak values structure. Base on those analyses, a strategy for star image's pretreatment was presented. The background and noise of the image is removed by a window transform of the pixel gray, all pixel whose gray value below the threshold will be set as a black pixel, the gray of which will be set as zero videlicet. The threshold is determined through the numeric statement of the background pixels by an iterative algorithm. Then a new algorithm for star point locating was presented by a two-step projection checking method. The horizon domains of the star points can be determined through the vertical projection checking of the image at first, then the horizon domain of each star point can be determined through the horizon projection in the horizon domains of the star points. The precise position of the star points is calculated using centroid method at last. The new algorithm is simpler and has smaller consumption of computing and memory than tradition connected domain methods. Experiments on real star images with size of 2048 x 2048 indicated the validity of the algorithm.