Structural compression for document analysis

In this paper we describe a structural compression technique to be used for document text image storage and retrieval. The primary objective is to provide an eecient representation, storage, transmission and display. A secondary objective is to provide an encoding which allows access to speciied regions within the image and facilitates traditional document processing operations without requiring complete decoding. We describe an algorithm which symbolically decomposes a document image and structurally orders the error bitmap based on a probabilistic model. The resultant symbol and error representations lend themseleves to reasonably high compression ratios and are structured so as to allow operations directly on the compressed image. The compression scheme is implemented and compared to traditional compression methods.