压缩包的内容包括：1.有关JPEG和DPCM算法的文章；2.实现其算法的压缩程序3.有关图像压缩方面的资料。读者请注意：

<1>这里讨论的是灰度图像的压缩不涉及彩色图像。

<2>实现压缩时，输入的图像数据采用一种自定义的格式（com 格式），前四个字节记录图像的宽度和高度，之后就是逐

行的图像数据，图像的开头和结尾没有任何标记。这种格式的图像数据是从BMP图像中得到的。

<3>这里没有JPEG算法的解压程序，压缩后的数据存成标准的JPEG文件格式，任何视图软件都可以打开。DPCM方法中的解

压缩程序将数据仍然存成com格式，可以将其转成PGM格式观看，压缩包中由com转为PGM格式的程序。

<4>所有的C程序均是在Linux（Rethat7.3)下完成。-Compressed package includes: 1. The JPEG and DPCM algorithm article　2. To achieve its compression algorithm procedure 3. The image compression information. Readers please note:

<1> discussed here is the gray image compression does not involve color images.

<2> to achieve compression, the input image data using a custom format (com format), record the first four bytes of the image width and height, and then is gradually

　 Line of image data, image mark the beginning and no end. This format of image data is obtained from the BMP image.

<3> There are no procedures for JPEG decompression algorithm, compressed data stored as a standard JPEG file format, you can open in any view. DPCM method of solution

　 Compressed program data is still stored as com format, you can watch it turn into a PGM format, compressed in the com format to PGM program.

<4> All the C programs are in Linux (Rethat7.3) to complete.