Image and Video Compression Artifact Reduction at Low Bit Rates Using Local Cosine Transform in Conjunction with Significance Map Coding

In this study, we present an image and video compression method, which is efficient at low bit rates and includes local cosine transform (LCT) and significance map coding. Low bit rate image or video coding causes distortion and artifacts such as blocking effect, which is induced by block-based discrete cosine transform (DCT). On the other hand, another block-based method, LCT, which implements DCT, decreases blocking artifact, because it folds contiguous blocks before applying DCT. Significance map coding (SMC) achieves better image/video quality and decreases artifacts when compared to the conventional DCT coding approach. We apply SMC in conjunction with LCT for further improvement as shown by the experiments.