Abstract: Much redundant information between document pages exists in the document image information system. The research on the compression method based on the pagcpage statistical features is significant. Set Redundancy Compression(SRC) is such a technique. It reduced the total entropy of the whole image set through utilizing the image page's similarity. Compression based on template differential(CTD) is an improved SRC. The similar image set was constructed by the template. "hhe coding performance was improved by adding the template image to the Min-Max Differential (MMI))coding/decoding model. It was proved theoretically that CTD's coding performance is higher than MMD's. It was demonstrated by experiments that both the CTD and MMI)are benefit to increase the compression ratio of image set, furthermore, and ChD is better than MMD.

Key words: Document image information system, Set redundancy, Image compression, Template differential