L1-L1 norms for face super-resolution with mixed Gaussian-impulse noise

In real world surveillance application, the captured faces are often low resolution (LR) and corrupted by mixed Gaussian-impulse noise during the acquisition and transmission processes. In this paper, we propose an effective patch-based face super-resolution method to reconstruct a high resolution (HR) face image given an LR observation that is corrupted by mixed Gaussian-impulse noise. To represent the corrupted image patches, a sparse regularization combined with an l\ data fitting term is proposed. In the proposed model, both the patch reconstruction term and the regularization term are in the l\ norm form. As a result, the model is called norms. In addition, since image pixels have nonnegative intensities, we further add a nonnegative constraint to the patch representation model. Experimental results demonstrate that the proposed norms based method can achieve superior face super-resolution performance over several state-of-the-art approaches based on the objective results in terms of P-SNR, as well as the visual perceptual quality.