New thoughts for onboard compression of satellite images
Compression has become a must for efficient storing and transmission of data acquired by satellites with increasing resolution and swath. However, for compression of raw data satellite images, impact of striping noise is inevitable. Variances of Digital Number (DN) values introduced by striping noise will surely impair continuity and smoothness of satellite image and reduce the efficiency of onboard compression. In this paper, using Beijing-1 small satellite images, origin and characteristics of striping noise caused by double channel linear CCD and its impacts on the compression process are analyzed. Then, based on properties of striping noise, an improved method for compression of raw data satellite images is proposed. The new compression method is applied to Beijing-1 small satellite raw data images and yields significant boost in compression performance. Ideas of the proposed algorithm can be easily realized with circuit modification and no adaptation is needed for post processing of the compressed images.