Research on the Radar Image Compression of VDR Based on SPIHT

In this paper, the radar image compression of voyage data recorder (VDR) is researched. A sheet of radar image is stored in a VDR after an interval of time, so the compression algorithm for radar image may be seen as immobile image compression. The image compression process includes discrete wavelet transform (DWT), quantization and entropy coding. First, the DWT and its fast Mallat algorithm is presented. Then, the character of the image after DWT is analyzed. The set partitioning in hierarchical trees (SPIHT) coder includes the function of quantization and entropy coding, the SPIHT coder is explained in this paper briefly. At last, several wavelet functions in common use are chosen to compress the radar image, and code for it with two coding algorithms: embedded zerotree wavelet (EZW) and SPIHT. The simulation results show the SPIHT is more effective than EZW