Constructing multilayer locality-constrained matrix regression framework for noise robust face super-resolution

Representation learning methods have attracted considerable attention for learning-based face super -resolution in recent years. Conventional methods perform local models learning on low-resolution (LR) manifold and face reconstruction on high-resolution (HR) manifold respectively, leading to unsatisfactory reconstruction performance when the acquired LR face images are severely degraded (e.g., noisy, blurred). To tackle this issue, this paper proposes an efficient multilayer locality-constrained matrix regression (MLCMR) framework to learn the representation of the input LR patch and meanwhile preserve the manifold of the original HR space. Particularly, MLCMR uses nuclear norm regularization to capture the structural characteristic of the representation residual and applies an adaptive neighborhood selection scheme to find the HR patches that are compatible with its neighbors. Also, MLCMR iteratively applies the manifold structure of the desired HR space to induce the representation weights learning in the LR space, aims at reducing the inconsistency gap between different manifolds. Experimental results on widely used FEI database and real-world faces have demonstrated that compared with several state-of-the-art face super-resolution approaches, our proposed approach has the capability of obtaining better results both in objective metrics and visual quality. (c) 2020 Elsevier Ltd. All rights reserved.