Image processor with error diffusion modulated threshold matrix
June 18, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesApparatus and method for generating a dispersed dot half tone picture from a continuous tone picture Shaded picture signal processing system and method Method of reproducing a picture having improved resolution Method and apparatus for the representation of gray scale values in facsimile transmission Method of processing medium tone picture Pattern recognition system Conversion of multilevel digital data to binary data Patent #: 4562486 InventorsApplicationNo. 716759 filed on 06/18/1991US Classes:382/275, Artifact removal or suppression (e.g., distortion correction)358/3.03, Error diffusion in gray level or halftone generation358/463, Noise elimination358/466, Variable thresholding technique382/252Error diffusion or dispersionExaminersPrimary: Mancuso, JosephAttorney, Agent or FirmInternational ClassG06K 009/38AbstractAn image processor performs error diffusion by thresholding an incoming gray pixel to black or white, comparing the difference between the black or white print value and the incoming pixel gray level and superimposing the difference on the next pixel gray level. The threshold value is read out from a threshold matrix which has been modulated with a pattern which is complementary to the known artifact pattern of the error diffusion process. Typically, the threshold matrix has sparce threshold values along one of its diagonals, the direction of the diagonal being perpendicular to the prevailing direction of artifacts generated by the error diffusion algorithm.Other References
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