利用小波变换将图象分解成一组多分辨率子图象,提出了一种改进的编码方案---利用子图象的灰度统计分布特性和人眼视觉特性的分配比特数；采用双金字塔数据结构对图象数据进行编码，充分利用子图象的相似性，进一步减少了数据量。10幅奶牛图象的平均压缩比达到26.2，平均信噪比为30.6dB具有较好的图象恢复质量.

wavelet transform is adopted to decompose an image into a group of multiresolution sub-images.An improved coding scheme is developed which have considered the gray distribution properties of sub-image and human being's vision.image data have been reduced farther by using dual-pyramid data structure for sub-image coding.which have great similarity with each other.The mean compression rate and signal-to-noise ratio for 10 cow's image is 26.2 and 30.6.respectively.The reconstructural quality of image is high.