Removal of blocking artifacts of DCT transform by classified space-frequency filtering
Image compression techniques based on block discrete cosine transform (BDCT) are widely used today. However, visually annoying blocking artifacts appear when the compression ratio is high. We propose an iterative method to remove these artifacts using block classification and space-frequency filtering. The new method is better than POCS (projections onto convex sets) and regularization methods in visual appearance as well as objective error measures.