Image interpolation using Shearlet based iterative refinement
This work addresses image interpolation for natural images, offering an incremental improvement over existing methods.
The paper tackles image interpolation by proposing an algorithm that uses shearlet-based sparse representation and iterative refinement, achieving an average PSNR gain of 0.8 dB over cubic spline interpolation on a dataset of 200 images.
This paper proposes an image interpolation algorithm exploiting sparse representation for natural images. It involves three main steps: (a) obtaining an initial estimate of the high resolution image using linear methods like FIR filtering, (b) promoting sparsity in a selected dictionary through iterative thresholding, and (c) extracting high frequency information from the approximation to refine the initial estimate. For the sparse modeling, a shearlet dictionary is chosen to yield a multiscale directional representation. The proposed algorithm is compared to several state-of-the-art methods to assess its objective as well as subjective performance. Compared to the cubic spline interpolation method, an average PSNR gain of around 0.8 dB is observed over a dataset of 200 images.