Maximum-likelihood parameter estimation for image ringing-artifact removal

At low bit rates, image compression codecs based on overlapping transforms introduce spurious oscillations known as ringing artifacts in the vicinity of major edges. Unlike previous works, we present a maximum-likelihood appr oach to the ringing-artifact removal problem. Our approach employs a parame ter-estimation method based on the k-means algorithm with the number of clu sters determined by a cluster-separation measure. The proposed algorithm an d its simplified approximation are applied to JPEG2000 compressed images. O ur results show effective and efficient removal of ringing artifacts.