Color balance algorithm with Zone system in color image correction

A particular and unwanted color dominates an image is referred to as color cast. In this paper, we describe a global color balance algorithm with Zone system to remove the color cast from the digital color images. The Zone system is a photographic technique which is based on previsualization for determining optimal film exposure and development. It is divided the full tonal levels into eleven zones ranging from zone 0 (pure black) to zone X (pure white), with zone V representing subjective middle gray which is corresponding to 18% reflectance. Therefore, we firstly transferred RGB to YCbCr color space. Next, according to the principle of the Zone system, we detected the color cast by comparing the averages of histograms of Cb and Cr components with zone V. The zone V was regarded as reference range to calculate the all of pixels value in YCbCr and then the adjusted parameters of RGB will be obtained. Experimental results exhibit the proposed algorithm can correct the color from the color cast. Finally, the proposed method was compared with other color balance algorithm in subjective and objective evaluations.