Guided iterative back-projection scheme for single-image super-resolution

The iterative back-projection (IBP) technique is an effective approach to single-image super-resolution (SR) reconstruction. However, the conventional IBP-based SR method suffers from a jaggy and ringing effect around the edges, as the up-sampling process and the back-projection of the reconstructed image are isotropic. In this paper, we present an improved IBP approach, namely guided iterative back-projection (GIBP), which employs an effective edge-guided interpolation method for up-sampling, and either a joint bilateral filter or a guided filter is used to constrain the projection of the error coefficients so as to suppress the noise and the ringing artifacts (i.e. the halo effect). To up-scale an image with an arbitrary ratio, we also propose an edge-persevering bilinear up-scaling interpolation method in cooperation with GIBP. Experimental results validate that the proposed algorithm can significantly improve SR reconstruction accuracy, while suppressing the main artifacts, such as the ringing and jaggy effects, and the noise created in the traditional IBP methods.