Patent Document ID: 7545540
Application ID: 11155982
Patent Status: 1

Claim One:
1. A method for detecting and removing at least one dropout color from color image data in a machine independent color space comprising: generating screen values and threshold values for a neutral color screen and each saturated color screen in a plurality of saturated color screens for a chrominance-luminance space; receiving chrominance-luminance color space image pixels; comparing a value for a chrominance and a value for a hue angle for each chrominance-luminance color space pixel to the threshold values for the neutral color screen and the saturated color screens to identify whether the chrominance-luminance color space pixel corresponds to one of the neutral color and saturated color screens; interpolating an intermediate color screen in response to none of the neutral color and saturated color screens being identified as corresponding to the chrominance-luminance color space pixel, the interpolation of the intermediate color screen being computed as follows: (1−{acute over (α)})*S n +{acute over (α)}*S n+1 where {acute over (α)}=(φ−φ n )/(φ n+1 −φ n ), S n is a screen value for a first saturated color screen of a pair of saturated color screens, S n+1 is a screen value for a second saturated color screen of the pair of saturated color screens; φ is a hue angle for the intermediate color screen, φ n is a hue angle for the first saturated color screen, and φ n+1 is a hue angle for the second saturated color screen; comparing a screen value for one of the identified neutral color screen, saturated color screen, and intermediate color screen to a corresponding value for a luminance component of the corresponding chrominance-luminance color space pixel; generating a dropout pixel for each chrominance-luminance color space image pixel having a corresponding value for the luminance component of the chrominance-luminance color space pixel that is less than the screen value for the identified neutral color screen, saturated color screen, and intermediate color screen corresponding to the chrominance-luminance color space pixel; generating a black image pixel or a grayscale image pixel for each chrominance-luminance color space image pixel having a corresponding value for the luminance component of the machine independent color space pixel that is greater than the screen value for the identified neutral color screen, saturated color screen, and intermediate color screen corresponding to the chrominance-luminance color space pixel; converting the dropout pixels, black image pixels, and the grayscale image pixels generated with reference to the received chrominance-luminance color space pixels into machine dependent color space pixels; and printing the machine dependent color space pixels in the machine dependent color space with an electrostatographic printing system.