Learning Deformable Hourglass Networks (DHGN) for Unconstrained Face Alignment

In this paper, we propose a deformable hourglass networks (DHGN) approach to investigate the problem of face alignment, especially in such challenging cases when faces undergo large variations including severe poses, diverse expressions and partial occlusions in unconstrained environments. Unlike conventional feature extractions which cannot explicitly exploit irregular geometric structures for facial shapes, our DHGN learns a deformable mask to reduce the variances of facial deformation and extract attentional facial regions for robust feature representation. To achieve this, we carefully design a differential module, dubbed the deformable transformer, which typically incorporates with a regression sub-net to predict a set of offsets and a masking operator to filter the semantic facial parts for feature representation learning. To further reinforce the alignment performance, we integrate our designed modules in the paradigm of stacked hourglass networks and jointly optimize the network parameters in an end-to-end manner. Extensive experimental results demonstrate very compelling performance in comparisons to most state-of-the-art methods.