基于自适应比特分配的SAR复图像频域压缩算法

研究合成孔径雷达(SAR)复图像数据的虚实部压缩算法,针对SAR复图像数据的统计特性,提出一种自适应比特分配的改进算法。首先在频域对SAR复图像数据进行自适应加权预处理,然后由香农率失真定理结合拉格朗日乘子法,推导了基于方差的块自适应虚实部最优比特分配公式,给出了整个压缩算法的流程图。根据流程图进行了多次压缩实验,并分析了算法的压缩性能。最后将改进算法与传统算法进行比较,验证了改进算法具有更优的幅度保持和相位保持的特点。

SAR Complex Image Compression Algorithm in Frequency Domain Based on Auto-bit Allocation

In this paper, SAR complex image compression algorithm in frequency domain is studied and an improved algorithm based on auto-bit allocation is proposed according to the statistical property of SAR complex image data. The improved algorithm adopts an adaptively weighed method in frequency domain. The formula of bit allocation between real and imaginary parts is deduced based on Shannon Rate-Distortion Theory and the Lagrange multiplier. A flow chart shows the procession of the whole compression algorithm. The algorithm performance is analyzed after the SAR complex image compression experiments. Finally, the improved algorithm is compared with the traditional algorithm. The performance of the improved algorithm is proved to be better in terms of the reservation of amplitude and phase information.