Class preserving projections and data augmentation for appearance-based face recognition

Computer Vision and Biometrics benefit from the recent advances in Pattern Recognition and Artificial Intelligence, which tends to make model-based face recognition more efficient. Also, deep learning combined with data augmentation tends to enrich the training sets used for learning tasks. Nevertheless, face recognition still is challenging, especially because of imaging issues that occur in practice, such as changes in lighting, appearance, head posture and facial expression. In order to increase the reliability of face recognition, we propose a novel supervised appearance-based face recognition method which creates a low-dimensional orthogonal subspace that enforces the face class separability. The proposed approach uses data augmentation to mitigate the problem of training sample scarcity. Unlike most face recognition approaches, the proposed approach is capable of handling efficiently grayscale and color face images, as well as low and high-resolution face images. Moreover, proposed supervised method presents better class structure preservation than typical unsupervised approaches, and also provides better data preservation than typical supervised approaches as it obtains an orthogonal discriminating subspace that is not affected by the singularity problem that is common in such cases. Furthermore, a soft margins Support Vector Machine classifier is learnt in the low-dimensional subspace and tends to be robust to noise and outliers commonly found in practical face recognition. To validate the proposed method, an extensive set of face identification experiments was conducted on three challenging public face databases, comparing the proposed method with methods representative of the state-of-the-art. The proposed method tends to present higher recognition rates in all databases. In addition, the experiments suggest that data augmentation also plays an essential role in the appearance-based face recognition, and that the CIELAB color space (L*a*b) is generally more efficient than RGB for face recognition as it attenuates lighting variations.