Color image correction based on characteristics of a highlights or other predetermined image portion
First Claim
1. A color image processing apparatus comprising:
- detecting means for detecting a pixel of a predetermined luminance from a color image signal consisting of a luminance signal and color difference signals;
correction amount operating means for calculating correction amounts to the color difference signals of each of pixels constituting an image from the color difference signals of the pixels of a predetermined luminance; and
correcting means for correcting the color difference signals of each of the pixels constituting the image in accordance with said correction amounts.
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Abstract
A color image processing apparatus comprises: a circuit to provide a color image signal consisting of a luminance signal and two color difference signals; a converter to convert the two color difference signals into the hue signal and saturation signal; a compressing circuit to independently compress the dynamic ranges of one of or both of the luminance signal and the saturation signal and to output; a memory to store the hue signal and the output of the compressing circuit; and a color printer to reproduce the color image on the basis of the hue signal, saturation signal, and luminance signal stored in the memory. The compressing circuit performs the compression on the basis of a frequency distribution of the input signal levels. With this apparatus, the color balance can be automatically adjusted by use of correction ROMs of a small memory capacity.
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Citations
25 Claims
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1. A color image processing apparatus comprising:
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detecting means for detecting a pixel of a predetermined luminance from a color image signal consisting of a luminance signal and color difference signals; correction amount operating means for calculating correction amounts to the color difference signals of each of pixels constituting an image from the color difference signals of the pixels of a predetermined luminance; and correcting means for correcting the color difference signals of each of the pixels constituting the image in accordance with said correction amounts. - View Dependent Claims (2, 3, 4)
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5. A color image processing apparatus comprising:
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detecting means for detecting a plurality of pixels of a high saturation from a color image signal consisting of a luminance signal and color difference signals; operating means for calculating the average value of the color difference signals of said plurality of high luminance pixels; and correcting means for correcting the color difference signals of each of the pixels constituting the image using said average value as a maximum correction amount. - View Dependent Claims (6, 7)
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8. A color image processing apparatus comprising:
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means for providing a color image signal consisting of a luminance signal and color difference signals; detecting means for detecting the color difference signals of a pixel of a high luminance from the color image signal; a conversion table of correction amounts for correcting the color difference signals of each of the pixels constituting the image of said color image signal; and correcting means for subtracting the correction amounts from said conversion table from the color difference signals of each component pixel of the image, wherein the luminance signal and color difference signals of the pixel to be corrected and the color difference signals of one or a plurality of pixels are input to said conversion table. - View Dependent Claims (9, 10, 11)
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12. A color image processing method comprising the steps of:
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detecting a highlight point in a color image; detecting a color component of the detected highlight point; supplying a luminance component of the color image other than that of the highlight point; and correcting a color component other than that of the highlight point in accordance with the luminance component and the detected color component. - View Dependent Claims (13, 14, 15, 16)
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17. A digital color image processing apparatus comprising:
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highlight point detecting means for detecting a highlight point in a color image; highlight point color component detecting means for detecting a color component of the detected highlight point; luminance signal supplying means for supplying a luminance component of the color image other than that of the highlight point; and correcting means for correcting a color component other than that of the highlight point in accordance with the luminance component and the detected color component. - View Dependent Claims (18, 19, 20, 21)
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22. A digital color image forming method comprising the steps of:
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detecting a highlight point in a digital color image data; detecting a color component of the detected highlight point; correcting a digital color component of the digital color image data in accordance with the detected color component of the detected highlight point; and forming a printed color image in accordance with the corrected digital color image data. - View Dependent Claims (23, 24, 25)
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Specification