Image Resolution Up-Conversion via Maximum a Posteriori Interpolator Sequence Estimation and Viterbi Algorithm

A new method of image resolution up-conversion based on maximum a posteriori sequence estimation is proposed. At each missing pixel of the high resolution (HR) image we consider an ensemble of candidate interpolation methods (interpolator). The interpolators are interpreted as states of a finite-state machine (FSM). Accordingly, the up-scaling problem is converted to the problem of estimating the optimal sequence of interpolators corresponding to the sequence of missing HR pixel positions. We derive a parameter-free probabilistic model for this FSM to solve the estimation problem using trellis diagrams and Viterbi algorithm. The experimental results prove that the proposed algorithm results sharper HR images and higher peak signal-to-noise ratios (PSNR) comparing to many algorithms in this domain.