Adaptive filter for reducing coding artefacts - uses dual transformation coding with threshold zeroing coeffts. followed by decoding and subtraction

摘要

Samples of the decoded binary signal are fed to a high pass circuit (1). The high-pass decoded signal is fed to an encoder (2) which carries out a transformation coding with it, by which the block structure and the transformation is the same as that of coding the decoded binary signal. A threshold circuit (3) sets each transformation coefficient of a block to zero where it is greater than the half-quantisation step used for this block in the coding of the decoded binary signal. A decoder (4) after the thresholder decodes the signal. The output data from this decoder are fed to a subtractor (5) also receiving the decoded binary signal. ADVANTAGE - No reduction of information content.