Color enhancement for graphic images

Abstract

A color enhancement system may enhance color components in an image. In one embodiment, the color enhancement system suppresses banding by combining an input color value with an enhanced colored value. In another embodiment, local variation in saturation values around a pixel may be used to determine a modification of an input saturation value for color enhancement. As still another embodiment, flickering between frames may be suppressed by combining a histogram that counts the number of times a given pixel value occurs in a particular image with a historical histogram that keeps track of an average of how often given values have occurred in previous frames.

1 . A method comprising:
 suppressing color banding by combining an original saturation value with a color enhanced value.   
   
   
       2 . The method of  claim 1  including using a weighted average of said original and color enhanced values. 
   
   
       3 . The method of  claim 1  including measuring the variation between a pixel and its neighbors to develop a measure of saturation enhancement. 
   
   
       4 . The method of  claim 3  including recording in a histogram counts of saturation values encountered within an image. 
   
   
       5 . The method of  claim 4  including changing the count based on the variation between a saturation value of a given pixel and the saturation values of its neighbors. 
   
   
       6 . The method of  claim 5  including combining a historical histogram with a histogram for a current image to develop a histogram to modify an input saturation. 
   
   
       7 . A method comprising:
 adjusting the saturation of an image based on the variation in saturation values between pixels in the image and the neighbors of those pixels.   
   
   
       8 . The method of  claim 7  including using a histogram to keep track of the number of occurrences of saturation values of pixels within an image. 
   
   
       9 . The method of  claim 8  including changing the count based on the local variation between a given pixel and its neighbors. 
   
   
       10 . The method of  claim 9  including using a modified histogram based on the changed count and a historical histogram taken over previous images and blending the historical and modified histograms. 
   
   
       11 . The method of  claim 10  including using a weighted average of the historical and modified histograms to form a blended histogram. 
   
   
       12 . The method of  claim 11  including using the blended histogram to modify the saturation values of input pixels. 
   
   
       13 . A method comprising:
 developing a current histogram of the occurrence of color values of pixels in an image;   maintaining a historical histogram that stores the color values of previously analyzed images; and   blending the historical and current histograms.   
   
   
       14 . The method of  claim 13  wherein developing a histogram includes developing a histogram of color values that are saturation values. 
   
   
       15 . The method of  claim 13  including using a weighted average to blend said current histogram and said historical histogram to form a blended histogram. 
   
   
       16 . The method of  claim 15  including storing the blended histogram as the new historical histogram. 
   
   
       17 . An apparatus comprising:
 a unit to generate an enhanced saturation value for a plurality of pixels; and   a banding suppression device coupled to said unit and to receive an input saturation value to combine the input saturation value with the enhanced saturation value to create an output saturation value.   
   
   
       18 . The apparatus of  claim 17 , said device to generate a weighted average of the input saturation value and the color enhanced saturation value. 
   
   
       19 . The apparatus of  claim 17  including a device to measure local saturation variance between a pixel and its neighbors. 
   
   
       20 . The apparatus of  claim 19 , said unit to develop a histogram of saturation values encountered within an image. 
   
   
       21 . The apparatus of  claim 20 , said unit to develop a histogram to change the histogram count based on the variation between a given pixel and the saturation values of its neighbors. 
   
   
       22 . The apparatus of  claim 21 , said unit to develop a histogram to combine an historical histogram with a histogram for a current image to develop a histogram to modify an input saturation. 
   
   
       23 . The apparatus of  claim 17  wherein device is a processor. 
   
   
       24 . The apparatus of  claim 23  wherein said device is a graphics processor. 
   
   
       25 . The apparatus of  claim 24 , said graphics processor to adjust the saturation of an image based on the variation in saturation values between pixels in the image and the neighbors of those pixels. 
   
   
       26 . The apparatus of  claim 24 , said graphics processor to develop a current histogram of the occurrence of color values of pixels in an image, to maintain an historical histogram that stores the color values of previously analyzed images, and to blend the historical and current histograms.