Sharp Kabushiki Kaisha Corporation

Sharp Laboratories of America, Inc

Makoto Otsu

William Ho Chang

Yasushi Adachi

Toshihiro Kanata

A method for color misregistration detection. Input image data is buffered and transferred to vector space. An examination window for a current pixel is established and foreground and background pixels within that window are selected. The current pixel is examined to determine if it is in an edge of a scanned object. If the current pixel is in an edge, it is deemed to have color misregistration. For pixels that have been deemed to have color misregistration, a correction value is determined and then adjusted prior to being applied to the pixel value.

Least squares method for color misregistration detection and correction in image data

A method for color misregistration detection. Input image data is buffered and transferred to vector space. An examination window for a current pixel is established and foreground and background pixels within that window are selected. The current pixel is examined to determine if it is in an edge of a scanned object. If the current pixel is in an edge, it is analyzed for color misregistration. The analysis includes an application of Stokes' theorem. If the results of the application of Stokes' theorem indicate that the color misregistration is above a threshold, the pixel is identified as having color misregistration.

Vector method for color misregistration detection in image data

An image processing apparatus includes: a parameter computing means which computes the maximum density value, the summation of density differences, the average density and the maximum density difference for each pixel in a mask containing a target pixel; and a color determination counting circuit which makes appropriate, selective threshold comparisons based on the computed result from the parameter computing circuit to determine an area in a mask as being chromatic, achromatic or 'the other' area.

Image processing apparatus

The present invention is an image processing apparatus comprising: dividing means for dividing an image signal obtained by scanning an original document into predetermined local blocks and output a predetermined including a target pixel; a binary coding processing section which converts the image signal in the predetermined block into binary code information; means for calculating each area (dimension) of the binary values; means for calculating number of times that the binary values are changed; a threshold processing section for performing threshold processing by properly and selectively using a threshold of the maximum density difference in the predetermined area, each area (dimension) value after binary coding and number of counts as a parameter; and a judgement processing section for judging the image signal in the predetermined area.

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Vancouver, WA, United States of America

Makoto Otsu