On single image scale-up using sparse-representations

  • Authors:
  • Roman Zeyde;Michael Elad;Matan Protter

  • Affiliations:
  • The Computer Science Department, Technion, Israel Institute of Technology, Haifa, Israel;The Computer Science Department, Technion, Israel Institute of Technology, Haifa, Israel;The Computer Science Department, Technion, Israel Institute of Technology, Haifa, Israel

  • Venue:
  • Proceedings of the 7th international conference on Curves and Surfaces
  • Year:
  • 2010

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Abstract

This paper deals with the single image scale-up problem using sparse-representation modeling. The goal is to recover an original image from its blurred and down-scaled noisy version. Since this problem is highly ill-posed, a prior is needed in order to regularize it. The literature offers various ways to address this problem, ranging from simple linear space-invariant interpolation schemes (e.g., bicubic interpolation), to spatially-adaptive and non-linear filters of various sorts. We embark from a recently-proposed successful algorithm by Yang et. al. [1,2], and similarly assume a local Sparse-Land model on image patches, serving as regularization. Several important modifications to the above-mentioned solution are introduced, and are shown to lead to improved results. These modifications include a major simplification of the overall process both in terms of the computational complexity and the algorithm architecture, using a different training approach for the dictionary-pair, and introducing the ability to operate without a training-set by boot-strapping the scale-up task from the given low-resolution image. We demonstrate the results on true images, showing both visual and PSNR improvements.