Image deblocking by transcoding DCT blocks to wavelet subbands

In this paper, we show how the DCT blocks can be transcoded to wavelet subbands for image deblocking in the wavelet domain. The approach is based on the transcoding of DCT blocks to wavelet coefficient subbands directly in the transform domain. The transcoding uses filtering (wavelet analysis) along with re-sampling (down) operation in the block DCT space. To perform transcoding, linear filtering is used in the block DCT domain. In this technique, filtering is performed on the three adjacent blocks. The complexity is reduced by performing sampling rate change and filtering operations in a single combined step. The proposed approach achieves the quality as same as the spatial domain technique at a reduced computational cost.