SuperFront: From Low-resolution to High-resolution Frontal Face Synthesis

Even the most impressive achievement in frontal face synthesis is challenged by large poses and low-quality data given one single side-view face. We propose a synthesizer called SuperFront GAN (SF-GAN) to accept one or more low-resolution (LR) faces at the input to then output a high-resolution (HR) frontal face with various poses and such to preserve identity information. SF-GAN includes intra-class and inter-class constraints, which allow it to learn an identity-preserving representation from multiple LR faces in an improved, comprehensive manner. We adopt an orthogonal loss as the intra-class constraint that diversifies the learned feature-space per subject. Hence, each sample is made to complement the others to its max ability. Additionally, a triplet loss is used as the inter-class constraint: it improves the discriminative power of the new representation, which, hence, maintains the identity information. Furthermore, we integrate a super-resolution (SR) side-view module as part of the SF-GAN to help preserve the finer details of HR side-views. This helps the model reconstruct the high-frequency parts of the face (i.e. periocular region, nose, and mouth regions). Quantitative and qualitative results demonstrate the superiority of SF-GAN. SF-GAN holds promise as a pre-processing step to normalize and align faces before passing to CV system for processing.