Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1995-11-07
1998-12-29
Coles, Edward L.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
395108, 358456, 358458, 358518, 358534, 358536, G06F 1500, H04N 140, G03F 308
Patent
active
058548823
ABSTRACT:
Halftone correction systems are provided for producing dot overlap corrected halftone images at a digital printer. In the first embodiment, a system is provided for halftone correction on a black-and-white digital printer. The system first calibrates the black-and-white digital printer with seven test patterns to provide halftone correction information. Multi-level digital image signals representing a continuous-tone image are then received and stored. The system next halftones these multi-level digital image signals to provide an overlap corrected halftone image responsive to the halftone correction information at the digital printer. Halftoning is performed using an overlap corrected ordered dithering screen, which was generated based upon the correction of the partial overlap of adjacent dots in an uncorrected ordered dithering screen. In the second embodiment, a system is provided for producing dot overlap corrected color halftone images on a digital color printer. The system first calibrates the digital color printer with a set of color test patterns to provide halftone correction information. Next, multi-level digital color image signals representing a continuous-tone color image are received and stored. The system then halftones the multi-level digital color image signals to provide an overlap corrected color halftone image responsive to the halftone correction information at the digital color printer. The system may halftone the continuous-tone color image by either color error diffusion or ordered dithering techniques. In the third embodiment, a system is provided for dot overlap correction of halftone images at a digital printer which is coupled to multiple computers in a network.
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Measurement of Printer Parameters for Model-based halftoning, T.N. Pappas, C.K. Dong and D.L. Neuhoff, Journal of electronic Imaging, vol. 2 (3), pp. 193-204, Jul. 1993.
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Coles Edward L.
Lukacher K.
Lukacher M.
The University of Rochester
Wallerson Mark
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