Method and apparatus for compressing and decompressing images of documents

摘要

A method and apparatus for compressing images having a binary extractor, a binary compressor and a JPEG compressor. The binary extractor produces a binary image representing an estimate of the binary information in the original image. The binary image is compressed by the binary compressor. The binary image is also subtracted from the original image to produce a difference image representing the continuous-tone information in the original image. The difference image is then compressed using the JPEG compressor. In this manner, the present invention compresses a document image without having to perform segmentation on the image.