Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1990-09-04
1993-04-20
Shaw, Dale M.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358 75, 358 80, 340703, G06F 1520, H04N 146, G09G 128
Patent
active
052049485
ABSTRACT:
In the present invention saturation is averaged for each pixel block of a predetermined size and a maximum saturation value is obtained for each of a predetermined number of block sizes. A sum total of maximum mean saturation values is obtained, basic chromaticity corresponding to the sum total is determined, and saturation values are each corrected by a hue of the corresponding pixel. X and Y correlation coefficient coordinates of the pixel positions having greater saturation values than a reference saturation value are obtained for each color, and a slanted striped pattern factor is determined corresponding to the correlation coefficient. The width of a striped pattern is detected for each color, the sum of the saturation values within the pattern width, a standard deviation of the pixel positions weighted by the saturation values and the number of pixels within the pattern width are multiplied, and a border striped pattern is determined corresponding to the multiplied value. The width of the striped pattern is similarly detected. A center striped pattern factor is determined corresponding to a value obtained by dividing the product of the sum of saturation values and the deviation of saturation by the standard deviation of pixel positions. Evaluated values of these color reproduction errors are multiplied by predetermined coefficients, respectively, and the sum total is obtained and is compared with a reference value to determine the quality of a color image signal.
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Advantest Corporation
Shaw Dale M.
Tung Kee M.
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