Lightweight Deep Residue Learning for Joint Color Image Demosaicking and Denoising

Color demosaicking and image denoising each plays an important role in digital cameras. Conventional model-based methods often fail around the areas of strong textures and produce disturbing visual artifacts such as aliasing and zippering. Recently developed deep learning based methods were capable of obtaining images of better qualities though at the price of high computational cost, which make them not suitable for real-time applications. In this paper, we propose a lightweight convolutional neural network for joint demosaicking and denoising (JDD) problem with the following salient features. First, the densely connected network is trained in an end-to-end manner to learn the mapping from the noisy low-resolution space (CFA image) to the clean high-resolution space (color image). Second, the concept of deep residue learning and aggregated residual transformations are extended from image denoising and classification to JDD supporting more efficient training. Third, the design of our end-to-end network architecture is inspired by a rigorous analysis of JDD using sparsity models. Experimental results conducted for both demosaicking-only and JDD tasks have shown that the proposed method performs much better than existing state-of-the-art methods (i.e., higher visual quality, smaller training set and lower computational cost).