Image analysis – Histogram processing – For setting a threshold
Patent
1992-01-14
1993-07-06
Couso, Jose L.
Image analysis
Histogram processing
For setting a threshold
382 27, 358456, G06K 936
Patent
active
052260941
ABSTRACT:
A method of image conversion takes an original print ready image at a first resolution scaling and orientation, and simulates printing that image by creating a representation of a page at the particular resolution, scaling and orientation. The image is then periodically sampled through the page with an aperture that corresponds to the desired output. Because the resolution, scaling and/or orientation of the "print" and "scan" are distinct, the aperture "sees" areas which may correspond to more than a single pixel on the original image, and thereby may derive a signal that is gray, i.e., the aperture may see an area that is neither completely black or white, and the image data derived will be considered gray. The gray image data, which may be definable at several bits per pixel, is then made print-ready by reducing the number of bits defining each pixel to a valid output state (0, 1 for a typical binary printer, 0, 1, 2, 3 for a quaternary printer, etc.). The reduction step is accomplished through error diffusion methods that maintain the local area gray density level. In color applications, each of the bitmaps representing a color separation, be it 2, 3, 4 or any other number, is treated independently with the same method.
REFERENCES:
patent: 4238768 (1980-12-01), Mitsuya et al.
patent: 4633503 (1986-12-01), Hinman
patent: 4651287 (1987-03-01), Tsao
patent: 4654721 (1987-03-01), Goertzel et al.
patent: 4668995 (1987-05-01), Chen et al.
patent: 4742553 (1988-05-01), Irwin
patent: 4783838 (1988-11-01), Matsunawa
patent: 4811239 (1989-03-01), Tsao
patent: 4943934 (1990-07-01), Hosoda et al.
patent: 4962542 (1990-10-01), Klees
patent: 4969202 (1990-11-01), Groezinger
"A Fast Algorithm for General Raster Rotation"; Graphics Interface '86, A. Paeth; p. 77; (1986).
Floyd et al., "An Adaptive Algorithm for Spatial Greyscale", Proc. of the S.I.D. 17/2, 75-77 (1976).
Costello Mark
Couso Jose L.
Xerox Corporation
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