Multi-Channel Deep Networks for Block-Based Image Compressive Sensing
This work addresses image quality degradation in multimedia applications due to blocking artifacts in CS, offering a novel solution that improves reconstruction for varying sampling rates, though it is incremental as it builds on existing deep network approaches.
The paper tackles the problem of blocking artifacts in block-based image compressive sensing (CS) by developing a multichannel deep network that exploits inter-block correlation, resulting in performance that significantly exceeds state-of-the-art methods with large margins in objective metrics and visual quality.
Incorporating deep neural networks in image compressive sensing (CS) receives intensive attentions in multimedia technology and applications recently. As deep network approaches learn the inverse mapping directly from the CS measurements, the reconstruction speed is significantly faster than the conventional CS algorithms. However, for existing network based approaches, a CS sampling procedure has to map a separate network model. This may potentially degrade the performance of image CS with block-wise sampling because of blocking artifacts, especially when multiple sampling rates are assigned to different blocks within an image. In this paper, we develop a multichannel deep network for block-based image CS by exploiting inter-block correlation with performance significantly exceeding the current state-of-the-art methods. The significant performance improvement is attributed to block-wise approximation but full image removal of blocking artifacts. Specifically, with our multichannel structure, the image blocks with a variety of sampling rates can be reconstructed in a single model. The initially reconstructed blocks are then capable of being reassembled into a full image to improve the recovered images by unrolling a hand-designed block based CS recovery algorithm. Experimental results demonstrate that the proposed method outperforms the state-of-the-art CS methods by a large margin in terms of objective metrics and subjective visual image quality. Our source codes are available at https://github.com/siwangzhou/DeepBCS.