黑白文档图像的高倍压缩

DOCUMENT BINARY IMAGE EFFECTIVE LOSSLESS COMPRESSION

黑白文档图像不同于常规的文本文件和图像文件，使用常规的压缩算法难以取得较高的压缩倍数．文中分析了常规文档的特性及使用常规算法的优缺点；并针对其特殊性，提出了一种无失真压缩算法，大大提高了压缩倍数，它采用文中提出的分块编码和游程编码的混合编码方法．实验证明，该方法的压缩比字典序压缩（ＡＲＪ，ＰＫＺＩＰ，ＬＺＷ等）约提高０．５～１．２，比常规游程编码提高约０．３～０．８．

Document binary image is different from text file and general image file. It's very difficult to reach high compress ratios using general compressing algorithms. In this paper, the characteristic of document is analyzed and a lossless mixed coding algorithm is proposed, which uses the block coding and run length coding (RLC). Experiments prove it can increase higher compress ratios by 0.5 to 1.2 compared with dictionary based coding (ARJ, LZW, PKZIP etc.) and by 0.3 to 0.8 compared with general RLC.