Suppression of ringing artifacts with an adaptive shrinkage algorithm

A non-iterative wavelet-based algorithm was proposed to reduce the ringing artifacts associated with a lossy compressed image. The proposed algorithm is based on the fact that increases in magnitude of the quantized wavelet coefficients lead to decreases in visual smoothness. Thus a shrinkage algorithm is applied to maintain visual smoothness. The proposed algorithm is, however, adaptive in nature, in which the amount of shrinkage depends on edge strength, region activity and compression ratio. Experimental results have confirmed that the adaptive algorithm could suppress the ringing artifacts and improve visual smoothness, especially around edges where ringing is severe.