Method for processing color-image signals from a three-color original and for forming output color image having black, white and either red or blue
First Claim
1. A color-image processing and image forming method for processing three color-image signals obtained by scanning a color original, including a red-image signal representing an intensity of red color of a pixel, a green-image signal representing an intensity of green color of a pixel, and a blue-image signal representing an intensity of blue color of a pixel, the color-image processing method comprising the steps of:
- a) selecting either red or blue as a designated color;
b) determining a color of the pixel as red, when red is selected as said designated color in the step a), if a value of said red-image signal is greater than a sum of a value of said green-image signal and a predetermined red correction value;
c) determining a color of the pixel as blue, when blue is selected as said designated color in the step a), if a value of said blue-image signal is greater than a sum of a value of said red-image signal and a predetermined blue correction value;
d) determining a color of the pixel as black when the color of the pixel has not been determined in the step b) or the step c); and
e) forming an output image in accordance with determination results obtained in the steps b), c) and d), wherein the output image has black, white and the designated color.
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Abstract
A color-image processing method is provided in which a two-color image can be formed in accordance with three color-image signals obtained by scanning a color original without having a color shear. A designated color is selected. A pixel is determined as the designated color by comparing the color-image signal with a sum of another color-image signal and a correction value. The pixel is determined as black when the color of the pixel has not been determined as the designated color. The pixel is determined as white by comparing intensity of the three color-image signal with predetermined threshold values. A color of a focus pixel is corrected by comparing linear patterns of colors of four consecutively arranged pixels including the focus pixel with a plurality of reference color patterns.
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Citations
15 Claims
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1. A color-image processing and image forming method for processing three color-image signals obtained by scanning a color original, including a red-image signal representing an intensity of red color of a pixel, a green-image signal representing an intensity of green color of a pixel, and a blue-image signal representing an intensity of blue color of a pixel, the color-image processing method comprising the steps of:
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a) selecting either red or blue as a designated color; b) determining a color of the pixel as red, when red is selected as said designated color in the step a), if a value of said red-image signal is greater than a sum of a value of said green-image signal and a predetermined red correction value; c) determining a color of the pixel as blue, when blue is selected as said designated color in the step a), if a value of said blue-image signal is greater than a sum of a value of said red-image signal and a predetermined blue correction value; d) determining a color of the pixel as black when the color of the pixel has not been determined in the step b) or the step c); and e) forming an output image in accordance with determination results obtained in the steps b), c) and d), wherein the output image has black, white and the designated color. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification