压缩过的图像是无法直接进行数字化处理的,如JPEG、GIF等格式的文件,此时首先要对图像文件解压缩,这就要涉及到一些比较复杂的压缩算法。-compressed image can t directly process digital operation.such as jpeg,gif format.firstly ,it need decompress ,which is deal with complex compression algrithm.