Ringing artifact reduction in the wavelet-based denoising

Wavelet is a well-known noise reduction tool for its several nice properties. Since the wavelet domain is a kind of transform domain, thresholding in it can cause problems at the neighborhood of discontinuous points, seen as a ringing artifact in a 2D image. In a low-bit rate network and a heavy error-prone environment, it is a serious problem for an end-user. We propose an efficient ringing reduction algorithm based on the standard wavelet decomposition. Since its structure is the reverse of the wavelet denoising method, our algorithm has advantages regarding computational load and memory efficiency over other ringing reduction filters. Experimental results show that the proposed algorithm dramatically reduces ringing along edges.