Block adaptive subband coding with optimized AMBTC
K.W. Chan, K.L. Chan · 2002
A block adaptive SBC is combined with an adaptive AMBTC for near perfect reconstruction. The input images are decomposed into 4 subbands and are individually coded by AMBTC. The AMBTC will adapt to the signal variance and switch the output from 1 to 4 levels dynamically. Its performance is further optimized by Dynamic Range Tuning (DRT) and Central Aggregate Optimization (CAO). To avoid costly high precision coder, the lowest frequency band is further split into a coded subband and a residue one. All bands are coded by the same coder. Bit allocation is furnished by the dynamic adaptability of AMBTC, and a bit-reduction scheme derived from signal statistics of respective subbands. This 5-band coding system eliminates the blockiness and the jagged edge artifact completely. The simulation result also leads the closest one by a great margin.>