Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1983-06-30
1985-10-08
Britton, Howard W.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358260, 358 96, H04N 712
Patent
active
045463859
ABSTRACT:
Graphic images are generally considered to be those images comprised of text and/or drawings. Data compression of graphics images is desired whenever a fast image transmission speed is desired in a limited band width channel. It is also used for storage of a large number of images in a limited capacity storage system. A high compression ratio is achieved by thresholding the graphics image to a bilevel black-white image at one bit per pixel and then employing a second data compression on the black-white image. At low resolution, bilevel images have poor quality at edges and a quality improvement is needed. The data compression apparatus and method disclosed separates the graphics image into at least first and second bit planes identifies edge pixels from the first bit plane indicating a black/white change, locates the edge pixels and generates at least a single bit for each edge pixel indicating whether the edge pixel has a maximum intensity value such as black or white or an intermediate gray intensity value. Intermediate values are not allowed except at edge pixels which enhances both quality and compressibility of the resulting graphics image.
REFERENCES:
patent: 3670096 (1972-06-01), Candy et al.
patent: 4006298 (1977-02-01), Fowler et al.
patent: 4115816 (1978-09-01), Moe et al.
patent: 4117470 (1978-09-01), Elliott
patent: 4210936 (1980-07-01), Cinque
patent: 4229768 (1980-10-01), Kurahayashi et al.
patent: 4259694 (1981-03-01), Liao
patent: 4266299 (1981-05-01), Chai et al.
patent: 4280144 (1981-07-01), Bacon
patent: 4339774 (1982-07-01), Temple
IBM Technical Disclosure Bulletin by J. L. Mitchell, "Vertical Reference Coding for Digital Gray-Level Images", vol. 22, No. 7, Dec. 1979, pp. 2980-2985.
"Bit-Plane Encoding of Continuous-Tone Pictures", by D. R. Spencer et al., Proceedings of the Symposium of Computer Processing in Communications, Apr. 8, 1969, vol. 19, Microwave Research Institute Symposia Series.
"Data Filter and Compression Apparatus and Method", Ser. No. 429,658, Filed 9/30/82 by W. B. Pennebaker et al.
Britton Howard W.
Clark George E.
Dowd Thomas P.
International Business Machines - Corporation
Kostak Victor R.
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