Using assorted color spaces and pixel window sizes for colorization of grayscale images

Abstract

There is no exact solution for colorization of grayscale images. In the initial work done [23], color traits transfer techniques to color grayscale images are proposed. The main focus of the techniques [23] is to minimise the human efforts needed in manually coloring the grayscale images. The human interaction is needed only to find a reference color image, then the job of transferring color traits from reference color image to grayscale image is done by proposed techniques. Here the techniques of color traits transfer to grayscale images are revisited with various color spaces as well as different sizes of pixel window. For the experimentation seven different color spaces are considered like RGB, Kekre's LUV, XYZ, YIQ, YUV, YCbCr and newly proposed YCbCg. The pixel window sizes used are total twelve ranging from window with size 1x2 to 4x2. So in all 84 different versions of color traits transfer to grayscale algorithms are tested over five different images for deciding the color space and pixel window size giving best quality of coloring. The experimental results gives that the YCbCr color space gives better coloring, and the pixel window of size 3x3 suits the best in all color spaces.