Although studied for decades, effective face recognition remains difficult to accomplish on account of occlusions and pose and illumination variations. Pose variance is a particular challenge in face recognition. Effective local descriptors have been proposed for frontal face recognition. When these descriptors are directly applied to cross-pose face recognition, the performance significantly decreases. To improve the descriptor performance for cross-pose face recognition, we propose a face recognition algorithm based on multiple virtual views and alignment error. First, warps between poses are learned using the Lucas–Kanade algorithm. Based on these warps, multiple virtual profile views are generated from a single frontal face, which enables non-frontal faces to be matched using the scale-invariant feature transform (SIFT) algorithm. Furthermore, warps indicate the correspondence between patches of two faces. A two-phase alignment error is proposed to obtain accurate warps, which contain pose alignment and individual alignment. Correlations between patches are considered to calculate the alignment error of two faces. Finally, a hybrid similarity between two faces is calculated; it combines the number of matched keypoints from SIFT and the alignment error. Experimental results show that our proposed method achieves better recognition accuracy than existing algorithms, even when the pose difference angle was greater than 30°. 
Cross-pose face recognition based on multiple virtual views and alignment error