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Brightness referenced color image correcting apparatus

  • US 5,278,641 A
  • Filed: 03/05/1991
  • Issued: 01/11/1994
  • Est. Priority Date: 05/14/1990
  • Status: Expired due to Fees
First Claim
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1. A color image processing apparatus comprising:

  • signal converting means for converting a color image signal into a first signal, influenced easily by brightness of an original image, and second and third signals, the second and third signals being influenced less easily by brightness of the original image,brightness estimating means including means for dividing a signal plane, defined by coordinate axes corresponding to the second and third signals, into a plurality of local regions, means for processing the first signal for each of the local region, to obtain a histogram about brightness for each of the local regions, means for comparing a level of the first signal appearing at a highest frequency in the histogram with a predetermined standard value to generate brightness information, and means for averaging the brightness information of each of the blocks using the highest frequency as a weight to obtain final brightness information; and

    brightness correcting means for correcting the color image signal in accordance with the final brightness information.

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