Improved Automatic Colorization by Optimal Pre-colorization

Automatic line-drawings colorization of anime characters is a challenging problem in computer graphics. The previous fully automatic colorization method suffers from colorization accuracy and costs colorization artists to validate and correct colorization errors. We propose to improve the colorization accuracy by introducing “pre-colorization” step into our production pipeline that requests user to manually colorize partial regions in line-drawings before doing automatic colorization. The pre-colorized regions work as clues to colorize the other regions and improve the colorization accuracy. We found an optimal region to be pre-colorized to obtain the best automatic colorization performance.