Research On Key Technology Of On-Satallite Real-Time Image Compression Equipment

As the development of digital technology, image compression becomes a separateimportant course to be researched. Satellite image compression technology differs fromnormal image compression technology, because it is more restricted on hardwarecondition,and requires further real-time characteristic. This paper mainly discusses theimage compression system based on lapped biothorgonal transform (LBT) andsimplified zero tree codec, and its realization.As we know, today the discrete wavelet transform (DWT) based imagecompression method is most widely used. The well ability of energy centralizing, themultiresolution characteristic and the zero tree construction of the transformed modulusmake the DWT based method perform well in the area of static image compression. Thecoding efficiency is higher than any other former method, and it is naturally gradationalto match multi-level requirement. However, DWT is not fit for satellite imagecompression and some portable equipment because of its high computation and highmemory requirement. Because of this, the paper brings forward the LBT based lowcomputation and low memory needed image compression method. In the method, LBTcosts only 38ï¼…computation as DWT, and the memory cost is even lower, only 1/15 ofDWT. Through the research of the characteristics of the LBT transform modulus, a typeof simplified zero tree codec is used the method, making the arithmetic fitable forsatellite image compression.Based on the LBT method, the paper discusses the realization of the satellite imagecompression experimental system, including the hardware design as well as the softwaredesign. The hardware is mainly constructed of multiple DSP and FPGA, which solvesthe high cost and low reliability of former designs based on multi FPGA. Theoptimization of the effecience of the code is emphasized in the software design.The experiment of standard test image compression indicates that, the performanceof the LBT based image compression system we designed, is already better than theJPEG2000 method in the aspect of the quality of resumed image. As our method ismuch easier to realize because of its low computation and low memory requirementcharacteristics, it bares much more practicability in the area of satellite imagecompression.