Patent ID: 6567559
Filing Date: 2003-05-20
Classification: G06T,H04N

Abstract:
A data processing method for compressing data representing a composite page comprising of solid, text and image areas to a specified compression ratio, comprising the steps of:dividing the uncompressed page is divided into equal size non-overlapping blocks before compression; classifying each block as TEXT, SATURATED TEXT, IMAGE or SOLID as follows: blocks with absolute central moments less than a predetermined alpha solid threshold are classified as SOLID, blocks with a per pixel absolute reconstruction error less than a predetermined error threshold and with a difference between a foreground value and a background value greater than or equal to a predetermined foreground/background threshold are classified as TEXT; TEXT blocks where the foreground color is 0 and the background color is at the maximum gray level are further classified as SATURATED TEXT, and all other blocks are classified as IMAGE; compressing the classified block with a compression algorithm best suited for that particular block's characteristics; and decompressing said compressed data in real time.