Patent ID: 6307962
Filing Date: 2001-10-23
Classification: G06T

Abstract:
A system for producing a compressed document from a document page composed of an array of pixel signals having values representative of gray scale comprising:means for subdividing said pixel signals of said document page into a matrix of blocks;means responsive to values of the pixel signals in the blocks for segmenting the document page into one or more macroblocks, each said macroblock being composed of a group of one or more of said blocks which are adjacent to each other in said matrix;means for locating one or more regions of one or more said blocks which are adjacent to each other in said matrix and are not part of said macroblocks, and determining the prevalent value of the pixel signals of said blocks in each said region to provide background data;means for classifying each of said macroblocks as being either one of two image types by analyzing for areas within one or more blocks of the macroblock having pixel signals which transition outside a range from each of two pixel values most prevalent among the pixel signals of the macroblock which are sufficiently different from each other;means for producing a map representing the blocks in said matrix which are of a first of said two macroblock types;means for thresholding the pixel signals in the blocks represented in said map into binary representations thereof to provide a binary image;means responsive to said pixel signals in said array for obtaining data signals representing the majority and minority gray scale levels of each macroblock which are of said first type;means for generating position data specifying the locations of the macroblocks in said matrix which are of a second of said two macroblock types; andmeans for generating said compressed document from said map, said binary image, said data signals representing said levels, the pixel signals for the macroblocks of said second type, said background data, and said position data.