Fast multi-resolution colorization of high-resolution gray images

Colorization could be used to increase the visual appeal of old black and white photos and movies. By means of colorization using optimization, one can add colors automatically to a monochrome image or movie after annotating the image with a few color scribbles, based on a simple premise-neighboring pixels in space that have similar intensities should have similar colors. However, the previous method may fail to deal with high-resolution gray images well because of its quite large size of computation. In this paper, the authors utilize features of the image colorization as an optimization problem to overcome this limitation. An image pyramid model with the edge detection is presented to reduce the computation size for the colorization. As a result, the new method can colorize high-resolution gray images to advantage in computing speed and visual effects.