A 3D nonlinear postprocessing algorithm is proposed in this paper for reducing coding artifacts produced by block based motion compensated transform coding. In the proposed algorithm, a separable 3D filtering structure is used: a space-variant FIR-Median Hybrid filtering is used in spatial domain, followed by a motion compensated nonlinear filtering in temporal domain. By using this structure, the coding artifacts in the reconstructed image sequence can be effectively reduced without blurring edges or moving objects in the image sequence. The simulation results showed that significant improvement in the picture quality of low bit-rate coded video sequences can be obtained by using the proposed algorithm.
"Adaptive spatial-temporal postprocessing for low-bit-rate coded image sequence", Proc. SPIE 2182, Image and Video Processing II, (23 March 1994); doi: 10.1117/12.171058; https://doi.org/10.1117/12.171058