Inhalt des Dokuments
Preprint 20-2014
Image interpolation using Shearlet based iterative refinement
Author(s) :
Haricharan Lakshman
,
Wang-Q Lim
,
Heiko Schwarz
,
Detlev Marpe
,
Gitta Kutyniok
,
Thomas Wiegand
Preprint series of the Institute of Mathematics, Technische Universität Berlin
Preprint 20-2014
MSC 2000
- 65T60 Wavelets
-
41A05 Interpolation
Abstract :
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.
Keywords :
Interpolation, Sparse representation, Shearlets