Parameter estimation in regularized reconstruction of BDCT compressed images for reducing blocking artifacts
Javier Mateos, Aggelos K. Katsaggelos, Rafael Molina · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1996
High compression ratios for both still images and sequences of images are usually achieved by discarding information represented by block discrete cosine transform (BDCT) coefficients which is considered unimportant. This compression procedure yields images that exhibit annoying block artifacts. In this paper we examine the reconstruction of BDCT compressed images which results in the removal of the blocking artifact. The method we propose for the reconstruction of such images, is based on a hierarchical Bayesian approach. With such an approach image and degradation models are required. In addition, unknown hyperparameters, usually the noise and image variances, have to be estimated in advanced or simultaneously with the reconstructed image. We show how to introduce knowledge about these parameters into the reconstruction procedure. The proposed algorithm is tested experimentally.