Facial point localization via neural networks in a cascade regression framework

摘要

Facial point detection gains an increasing importance in computer vision as it plays a vital role in several applications such as facial expression recognition and human behavior analysis. In this work, we propose an approach to locate 49 facial points via neural networks in a cascade regression fashion. The localization process starts by detecting the face, followed by a face cropping refinement task and lastly arriving at the facial point location through five cascades of regressors. In particular, we perform a guided initialization using holistic features extracted from the entire face patch. Then, the points location is refined in the next four cascades using local features extracted from patches enclosing the prior estimates of the points. The generalization capability was improved by performing feature selection at each cascade. By evaluating our approach on samples gathered from four challenging databases, we achieved a location average error for each point ranging between 0.72 % and 1.57 % of the face width. The proposed approach was further evaluated according to the 300-w challenge, where we achieved competitive results to those obtained by state-of-the-art approaches and commercial software packages. Moreover, our approach showed better generalization capability. Finally, we validated the proposed enhancements by studying the impact of several factors on the point localization accuracy.