Image Compression Algorithm Based on Decreasing Bits Coding

In this paper, a new image compression algorithm based on decreasing bits coding, a conception of compression cell, and compression operator about a number of consecutive Z are put forward. The basic idea is as follows. First, wavelet coefficients, with adaptive threshold to determine the relationship are divided into three situations. They are positive P greater than or equal to the threshold, a negative N greater than or equal to the threshold, and Z less than the threshold. Then, it encodes in accordance with the order of character encoding, decreasing bits coding, binary bits encoding. Experiments have showed that the compression algorithm based on decreasing bits coding proposed by the article had a substantial reduction in the encoding length when having the same recovery quality with EZW. And the main scanning saved 35.82% coding bits on average when restored completely, especially in the high compression ratio. The compression effects became more prominent.