Stacked attention hourglass network based robust facial landmark detection

Deep learning based facial landmark detection (FLD) has made rapid progress. However, the accuracy and robustness of FLD algorithms are degraded heavily when the face is subject to diverse expressions, posture deflection, partial occlusion and other uncertain circumstances. To learn more discriminative representations and reduce the negative effect caused by outliers, a stacked attention hourglass network (SAHN) is proposed for FLD, where new attention mechanism is introduced. Basically, in the design of SAHN, a spatial attention residual (SAR) unit is constructed such that relevant areas of facial landmarks are specially emphasized and essential features of different scales can be well extracted, and a channel attention branch (CAB) is introduced to better guide the next-level hourglass network for feature extraction. Due to the introduction of SAR and CAB, only two hourglass networks are stacked as the proposed SAHN with fewer parameters, which is different from traditional SHNs stacked by four hourglass networks. Furthermore, a variable robustness (VR) loss function is introduced for the training of SAHN. The robustness of the proposed model for FLD is guaranteed with the help of the VR loss by adaptively adjusting a continuous parameter. Extensive experimental results on three public datasets including 300W, WFLW and COFW confirm that our method is superior to some previous ones.(c) 2022 Elsevier Ltd. All rights reserved.