Edge enhancement for subband coded images

Subband coding is a well-established technique. Coding algorithms, however, rarely try to exploit residual similarities between subbands in order to get both coding gain and improvement in visual appearance. In this work we propose a simple postprocessing technique for edge enhancement and ringing-artifact reduction in subband-coded images. The proposed technique employs morphological filtering for preliminary image simplification and uses a novel dual-window nonlinear operator for subsequent edge enhancement. Visual appearance and numerical results confirm the validity of the approach. A simple coding scheme, designed to test the efficiency of the approach, gives good results.