A Flexible and Effective Colorization System

This paper presents a flexible and effective colorization system that carries out colorization by performing two stages of chrominance determination for pixels in a gray-scale image, including scribble region expansion and chrominance blending. The region corresponding to each scribble color is determined by expanding the scribbles in parallel associated with the edge map of the given image. Usually a few pixels remain unassigned to a color region after this stage. For those pixels we define and compute the transportation distance between each pixel and each scribble color. Then the reciprocals of the distances are used as weights to assign each of those pixels a weighted sum of the scribble colors. To promote practicability and effectiveness of the system several modules are provided that make the system more user-friendly and enhance the colorization results. The experimental results show that the proposed system is not only flexible and easy to use, but it also provides natural and satisfactory colorization results.