Image super-resolution based on adaptive joint distribution modeling
This paper combines an adaptive reconstruction based approach and a learning based technique into an effective scheme for single image super-resolution. Unlike conventional schemes that adopt pre-trained dictionaries to tell the relationship between high-resolution (HR) image and the low-resolution (LR) observation, the proposed method attempts to learn the joint distribution of highly-correlated patch couples from the input image itself instead of an external dataset, so that the learnt models are specially tailored for the current patches and thus can better fit the image data of interest. To be specific, we first apply spatially adaptive gradient sparsity regularization in the reconstruction of the HR image using the contour information, and then utilize the generated HR output to guide the joint distribution learning to infer the relationship between the highly-correlated HR and LR patches. In this way, we simultaneously exploit the inter-scale correlation as well as the local and non-local correlation of the image contents. Empirical results show that the performance of the proposed method is highly competitive with state-of-the-art schemes in terms of peak signal-to-noise ratio (PSNR) and perceptual quality.