Colorization-based coding by focusing on characteristics of colorization bases

Colorization is a method that adds color components to a grayscale image using only a few representative pixels provided by the user. A novel approach to image compression called colorization-based coding has recently been proposed. It automatically extracts representative pixels from an original color image at an encoder and restores a full color image by using colorization at a decoder. However, previous studies on colorization-based coding extract redundant representative pixels and do not extract the pixels required for suppressing coding error. This paper focuses on the colorization basis that restricts the decoded color components. From this viewpoint, we propose a new colorization-based coding method. Experimental results revealed that our method can drastically suppress the information amount (number of representative pixels) compared conventional colorization based-coding while objective quality is maintained.