Deep Wide-Activated Residual Network Based Joint Blocking and Color Bleeding Artifacts Reduction for 4:2:0 JPEG-Compressed Images

Blocking and color bleeding are two well-known artifacts for 4:2:0 JPEG-compressed images. Blocking mainly results from the block-level quantization of the luma component, while color bleeding is mainly caused by the subsampling and quantization of chroma components. Restoring luma can reduce blocking distortion, but with little influence on color bleeding. On the contrary, color bleeding can be removed via chroma components restoration. This letter proposes a deep wide-activated residual network for reducing blocking and color bleeding artifacts simultaneously, in which the luma and chroma components are jointly restored. Chroma components usually suffer from more severe distortion than the luma component due to subsampling and coarse quantization. Thus, we use the luma component to guide the restoration of chroma components. Moreover, we reduce blocking and color bleeding artifacts in low-resolution space via pixel shuffle-based decimation and assembling, which allows to obtain high restoration speed. Experimental results show that the proposed approach achieves state-of-the-art performance on joint blocking and color bleeding artifacts reduction.