Image upscaling using multiple dictionaries of natural image patches

Abstract

We propose a new high-quality up-scaling technique that extends the existing example based super-resolution (SR) framework. Our approach is based on the fundamental idea that a low-resolution (LR) image could be generated from any of the multiple possible high-resolution (HR) images. Therefore it would be more natural to use multiple predictors of HR patch from LR patch instead of single one. In this work we build a generic framework to estimate an HR image from LR one using an adaptive prior (select the predictor locally) based on the local statistics of LR images. We use natural image patch prior as the HR image statistics. We partition the natural images into documents and group them to discover the inherent topics using probabilistic Latent Semantic Analysis (pLSA) and also learn the dual dictionaries of HR and LR image patch pairs for each of the topics using sparse dictionary learning technique. Then for test image we infer locally which topic it corresponds to and then we use the corresponding learned dual dictionary to generate HR image. Experimental results show the effectiveness of our method over existing state-of-art methods. © 2013 Springer-Verlag.