Colorization of Gray Images Based on Histogram Mapping and Image Layers
We propose a fast algorithm named HisT for colorizing gray images by transferring colors from a source, color image to a destination, gray image. Instead of choosing RGB color space, we process images in lαβ color space, which minimizes correlation between channels. As gray image varies only along luminance, colors based on the luminance histograms of the two images are transferred as follows. In the first step, we match luminance histogram scales between images, and transfer the mean of chromatic information from the source to the target, where we get the transition image. Secondly, we split the color image and transition image into layers, and impose improved color transfer equations onto each pixel in the transition image, which is used for color transfer between corresponding layers from color image to transition image. The experimental results prove that the HisT algorithm proposed herein is a fast algorithm with little human interactivity.