JPEG-matched MRC compression of compound documents
Mixed raster content (MRC) is an ITU document compression standard (T.44) specifying both a model for multilayer representation of a compound document, and a set of allowable standardized coders for the individual layers. The model requires decomposition of a document into two image layers and a binary mask layer, but the standard does not recommend any procedure for this task. For best compression results, the decomposition method should be optimized for the layer encoders. In this paper, a high performance MRC compound document codec is presented, where the layer decomposition scheme is matched to the JPEG encoder with arithmetic coding for the foreground and background image layers. JBIG is used to code the mask layer. Integrated noise removal routines enable handling of scanned documents along with electronic ones. Resolution scalable decoding features are also implemented. The page segmenter yields a segmentation mask, which serves to separate text and other features.