US Patent 7355529 Binary image compression apparatus and method

A binary image compression apparatus and method. The apparatus to compress a binary image includes a symbol extraction unit to extract symbols from a binary image, a symbol dictionary including a plurality of representative symbols registered therein and to register one or more of the extracted symbols when the one or more extracted symbols do not match the registered representative symbols, a symbol matching unit to perform a matching operation of the extracted symbols with the representative symbols using a plurality of thresholds to determine an index of the extracted symbols, and an encoding unit to compress symbols registered in the symbol dictionary and corresponding indexes, to compress indexes of the symbols extracted from the binary image and position information of each of the extracted symbols, and to generate a final bitstream from the compressed symbols, indexes, and position information.