COLORIZATION MATRIX CONSTRUCTION WITH HIGH COMPRESSION EFFICIENCY FOR COLORIZATION-BASED CODING USING OPTIMIZATION

In colorization-based coding, a chrominance component is reconstructed by applying a colorization matrix to a vector which contains a few color information. The conventional method formulated the colorization-based coding problem into an optimization problem. Since this approach obtains the optimal color information with respect to a given colorization matrix in the sense that it minimizes the reconstruction error, the compression efficiency depends on the colorization matrix. In this paper, we propose a colorization matrix construction with high compression efficiency for the colorization-based coding using optimization. To improve the ability to reconstruct the chrominance component, we construct our proposed colorization matrix based on a luminance-chrominance correlation in a local area. Furthermore, we embed an edge-preserving smoothing filtering process into the colorization matrix to reduce artifacts. The experimental results show that our method achieves better reconstruction of the chrominance component and higher compression efficiency compared with the conventional method.