关键词: 彩色图像, 灰度变换, 彩色空间, 亮度/色度

Abstract: Gray level transform will enhance contrast of color image if the technique straightly applies to R，G and B components，but color distortion will be introduced.MSRCR based on Retinex theory can improve visual effect of color image and not produce color distortion.However MSRCR must specify control parameters，namely its adaptivity is not well.And worse disadvantage of MSRCR is huge computation due to convolution，so processing time is much long.A novel adaptive color image enhancement algorithm is proposed.Original RGB image and the image with implementing gray level transform are all converted to nonlinear luminance/chroma color space.Consequently chroma component of the former and luminance component of the latter are recomposed，so the original color is preserved.This algorithm fully inherits advantages of gray level transform，such as extending effective gray levels，advancing whole contrast，improving image detail，and simple computation complexity，and parameters adaptability.So this algorithm can be applied to adaptive real time color image processing.

Key words: color image, gray level transform, color space, luminance/chroma