Bi-level Facsimile Compression with Unconstrained Tilings

A technique for bi-level facsimile compression is presented that extends to two-dimensional e sequences the traditional notion of run length coding. The algorithm is relatively efficient and asy to implement and exploits two-dimensional neighboring pixel redundancies, unlike that of s many existing systems employing entropy coding on raster scanned images, A bi-level image is patially predicted and then partitioned into rectangles of arbitrary dimensions that cover either s only white pixels or mixtures of black and white pixels. An entropy coded index is used to pecify the quantized length and width values of each rectangle from top to bottom and left to " a right in the image so that the decoder can deduce the rectangle locations using a "water-filling lgorithm. The rectangles containing some black pixels are encoded using entropy coding.