A simulated annealing restoration algorithm for restoring halftoned color-quantized images

Restoration of color-quantized images is rarely addressed in the literature especially when the images are color-quantized with halftoning. Most existing restoration algorithms are generally inadequate to deal with this problem as they were proposed for restoring noisy blurred images. In this paper, a restoration algorithm based on simulated annealing is proposed to solve the problem. This algorithm makes a good use of the available color palette and the mechanism of a halftoning process to derive useful a priori information for restoration. Simulation results show that it can improve the quality of a halftoned color-quantized image remarkably in terms of both SNR and CIELAB color difference metric. The subjective quality of the restored images can also be improved. (c) 2005 Elsevier B.V. All rights reserved.