Dictionary learning (DL) has now become an important feature learning technique that owns state-of-the-art recognition performance. Due to sparse characteristic of data in real-world applications, DL uses a set of learned dictionary bases to represent the linear decomposition of a data point. Fisher discrimination DL (FDDL) is a representative supervised DL method, which constructs a structured dictionary whose atoms correspond to the class labels. Recent years have witnessed a growing interest in multi-view (more than two views) feature learning techniques. Although some multi-view (or multi-modal) DL methods have been presented, there still exists much room for improvement. How to enhance the total discriminability of dictionaries and reduce their redundancy is a crucial research topic. To boost the performance of multi-view DL technique, we propose an uncorrelated multi-view discrimination DL (UMDDL) approach for recognition. By making dictionary atoms correspond to the class labels such that the obtained reconstruction error is discriminative, UMDDL aims to jointly learn multiple dictionaries with totally favorable discriminative power. Furthermore, we design the uncorrelated constraint for multi-view DL, so as to reduce the redundancy among dictionaries learned from different views. Experiments on several public datasets demonstrate the effectiveness of the proposed approach.

Sparse representation has been a very active research area in recent years. Similarity analysis is an attractive research topic in the field of pattern recognition. In this paper, we take advantage of sparse representation in similarity analysis, and propose a novel unsupervised feature extraction approach, named similarity preserving analysis based on sparse representation (SPASR). SPASR projects samples from a high-dimensional space into a low-dimensional subspace, where the sparse reconstructive similarity relations among samples and the similarities of original samples and sparsely reconstructed samples are preserved. Experiments on the AR face database and COIL-20 object database demonstrate that the proposed SPASR approach outperforms several representative unsupervised subspace learning methods.

The key of color face recognition technique is how to effectively utilize the complementary information between color components and remove their redundancy. Present color face recognition methods generally reduce the correlations between color components in the image pixel level, and then extract the discriminant features from the uncorrelated color face images. In this paper, we propose a novel color face recognition approach based on the holistic orthogonal analysis (HOA) of discriminant transforms of color images. HOA can reduce the correlation of color information in the feature level. It in turn achieves the discriminant transforms of red, green and blue color images by using the Fisher criterion, and simultaneously makes the achieved transforms mutually orthogonal. Experimental results on the AR and FRGC-2 public color face image databases demonstrate that the proposed approach acquires better recognition performance than several representative color face recognition methods.