Superresolution Alignment with Innocence Assumption: Towards a Fair Quality Measurement for Blind Deconvolution

Abstract : Quantitative measurements of restoration quality in blind deconvolution are complicated by the necessity to compensate for opposite shifts of reconstructed image and point-spread function. Alignment procedures mentioned for this purpose in the literature are sometimes not exactly enough specified; alignment-free approaches sometimes do not take into account the full variability of possible shifts. We investigate by experiments on a simple test case the errors induced by interpolation-based alignment procedures. We propose a new method for MSE/PSNR measurement of image pairs involving non-integer displacements that is based on a superresolution approach. We introduce an innocence assumption in order to keep deviations that can be explained by shifted sampling grids out of the error measurement. In our test case, the new measurement procedure reduces the variations in MSE/PSNR measurements substantially, creating the hope that it can be used for valid comparisons of blind deconvolution methods.