漂移扫描相机中拖尾现象快速消除方法

对同步卫星进行观测时,由于漂移扫描CCD相机的帧转移特性,若所拍摄星空中出现亮星,则会出现贯穿星图的smear拖尾现象。通过分析smear拖尾现象的成像机理,提出一种快速smear拖尾消除方法。首先,利用多项式拟合消除背景不均匀性;然后,计算并拟合星图每列灰度平均值,通过比较拟合前后的灰度平均值判断拖尾所在列;最后,通过将拖尾像素赋拟合后的灰度平均值消除拖尾。实验结果表明,该算法不但能够有效去除拖尾,减小星图背景均值差,而且其处理时间仅为常规smear拖尾去除算法的20%,验证了算法的有效性。

Fast removal algorithm for trailing smear effect in CCD drift-scan star image

When drift-scan CCD shooting the sky where bright stars are in the filed of view, because of the frame transfer feature, the trailing smear will appear throughout the star image. A fast smear trailing elimination algorithm was proposed by analyzing the imaging mechanism. The method firstly decreased the background non-uniformity by fitting the background, then located smear trailing by calculating the mean gray value of every column in star image and comparing the mean gray values before and after fitting, finally eliminated smear trailing by setting the trailing pixel with the mean gray value after fitting. The experimental results show that the smear trailing is removed completely and the mean deviation of background is apparently reduced, moreover the consuming time of this method is only 20% of that of traditional smear elimination method, which proves the validity of the method.