Dual Sparse Constrained Cascade Regression for Robust Face Alignment.

Localizing facial landmarks is a fundamental step in facial image analysis. However, the problem continues to be challenging due to the large variability in expression, illumination, pose, and the existence of occlusions in real-world face images. In this paper, we present a dual sparse constrained cascade regression model for robust face alignment. Instead of using the least-squares method during the training process of regressors, sparse constraint is introduced to select robust features and compress the size of the model. Moreover, sparse shape constraint is incorporated between each cascade regression, and the explicit shape constraints are able to suppress the ambiguity in local features. To improve the model's adaptation to large pose variation, face pose is estimated by five fiducial landmarks located by deep convolutional neuron network, which is used to adaptively design the cascade regression model. To the best of our best knowledge, this is the first attempt to fuse explicit shape constraint (sparse shape constraint) and implicit context information (sparse feature selection) for robust face alignment in the framework of cascade regression. Extensive experiments on nine challenging wild data sets demonstrate the advantages of the proposed method over the state-of-the-art methods.