In this paper, we propose an improved color-gamut method for liquid crystal displays (LCD) with multi-phosphor white light emitting diodes (MPW LED) and a modified rich color image processing approach with skin protection. The color saturation is always used to broaden the color-gamut. By increasing the color saturation, the expanded color-gamut can be observed in the CIE 1931 color space. The human skin color is typically memorized by color information. In order to increase the color saturation, the traditional rich color method makes skin color appear unnatural, so a modified rich color method with human skin color protection is proposed. The skin color protection generates normalized chrominance and illumination features. The skin chrominance model uses the normalized color-information of the skin as a classifier in a real-time skin pixel detection system. Several geometric patterns are used to tune the skin chrominance model with the principal components in color space to give the system a better detection performance. Consequently, the skin region information is used to tune the enhancement parameter in the modified rich color image processing approach. In comparison, the proposed approach yields a better image quality than the traditional one. In mobile display systems, due to the limitation of bandwidth and memory capacity, determining how to realize the functions of a wide color-gamut improvement method with skin protection on mobile display platform is very important. Ultimately, we have implemented our proposed method in the FPGA and displayed the image on the ARM platform.