25-4 DCT符号化における係数打切りの影響とその妨害除去フィルタの検討 An Artifact Reduction Technique for the case of DCT Coefficient truncation

In very low bitrate image coding, DCT coeffcients tend to be quantized so coarcely that in effect most of them are truncated. The resulting artifacts are investigated from the view point of aliasing and anti-aliasing filters are proposed. Simulation results show that they lead to subjectively pleasing reconstructed images.