Patent ID: 7474446
Filing Date: 2009-01-06
Classification: H04N

Abstract:
1. A color reduction processing apparatus, comprising: an image data acquisition unit configured to acquire RGB color image data defined by RGB color values; a conversion processing unit configured to convert the RGB color image data to HLS color image data defined by HLS color values; and a color reduction processing unit configured to convert the HLS color image data to print image data that comprises a first color, a second color, and a non-printing color based on specific parameters; a parameter setting unit configured to set a hue range Hs for the second color, wherein the color reduction processing unit converts the HLS color image data to print image data based on the hue range Hs setting; and wherein the first color is black, and the color reduction processing unit comprises: a hue ratio calculation unit configured to calculate a hue ratio Hr based on the equation: a lightness ratio calculation unit configured to calculate a lightness ratio Lr between the lightness of the target pixel Lp and the lightness of the second color L a saturation ratio calculation unit configured to calculate a saturation ratio Sr between the saturation of the target pixel Sp and the saturation of the second color S a second color data calculation unit configured to calculate a second color ratio R a first color data calculation unit configured to calculate a first color ratio Rk based on the equation: