De-ringing using morphological filters for waveletbased compressed image

JPEG2000 Standard is a new generation image compression technique, enabling encoding images at low bit-rates with acceptable quality. Since JPEG2000 is based on wavelet transforms, the reconstructed image will contain perceivable ringing artifacts in medium and low bit-rate regimes of lossy compression. This work utilizes a quad-tree partitioning scheme for post-processing the reconstructed image in a spatially varying manner and presents a voting strategy to determine a set of morphological filters to be used for reducing the ringing artifacts. Simulation results demonstrate that the proposed technique enhances reconstructed image quality compared to unprocessed JPEG2000 output at an equivalent bit-rate accounting for the side-information overhead, in terms of both PSNR and Visible Ringing Measure (VRM).