Color space appearance model video processor

摘要

A method of color processing determines whether a pixel color is within at least one range of predetermined colors corresponding to a viewer expected color. If so, the method altering the pixel color to better approximate the viewer expected color. For detection of skin tones determining whether the pixel color is within a range of predetermined colors includes discounting an illuminant of the pixel color. The viewer expected colors are preferably skin tone, grass green and sky blue. The saturation level of grass green and sky blue are enhanced and that of skin tones are suppressed. The saturation s is limited based upon lightness J and hue h to convert to an allowable RGB color format range.

主权项

1. A color processing apparatus comprising:
an input for receiving color pixel information of a video consisting of plural frames of a rectangular two dimensional array of pixels in a first color format; a color space converter receiving the color pixel information for each pixel and converting the color pixel information from the first color format to a Jhs format consisting of lightness J, hue h and saturation s for each pixel; a color processor having an input receiving color pixel information converted into the Jhs format including
a memory color block comparing a lightness J and a hue h color pixel information for each pixel with at least one range of predetermined colors corresponding to a viewer expected color and determining whether the pixel color of the pixel is within the at least one range of predetermined colors corresponding to a viewer expected color,a gain controlled amplifier having an input receiving the saturation s of each pixel, an output and a gain control input, the gain controller amplifier amplifying a signal at the input an amount corresponding to a signal at the gain input, anda gain calculation unit connected to the memory color block and the gain controlled amplifier operable to control the gain of the gain controlled amplifier corresponding to the determination whether the pixel color of the pixel is within the at least one range of predetermined colors corresponding to a viewer expected color of the memory color block.