Method and device of skin tone optimization in a color gamut mapping system

摘要

In a method of skin tone optimization in a color gamut mapping system, an image signal is first transformed from a predetermined color domain to an HSV color domain for generating an HSV image signal. Next, a skin tone optimization is performed on the HSV image signal for generating an adjusted saturation gain. Then, a color enhancement is performed on the HSV image signal according to the adjusted saturation gain and a color shift signal so as to generate a color enhancement signal. Finally, the color enhancement signal is transformed from the HSV color domain to the predetermined color domain.

主权项

1. A method of skin tone optimization in a color gamut mapping system, which is implemented in an image processor for performing the steps of:
(A) transforming an image signal from a predetermined color domain to an HSV (Hue, Saturation, Value) color domain for generating an HSV image signal; (B) performing a skin tone optimization on the HSV image signal for generating an adjusted saturation gain, wherein step (B) comprises the steps of: (B1) receiving the HSV image signal, color boundaries, saturation boundaries, and brightness boundaries to generate a hue smooth factor, a saturation smooth factor, and a brightness smooth factor; (B2) generating a gain adjusting factor by performing a mean operation according to the hue smooth factor, the saturation smooth factor, and the brightness smooth factor; and (B3) performing a weight adjustment on a saturation gain and a skin tone gain according to the gain adjusting factor; (C) performing a color enhancement on the HSV image signal according to the adjusted saturation gain and a color shift signal so as to generate a color enhancement signal; and (D) transforming the color enhancement signal from the HSV color domain to the predetermined color domain.