Locality-preserving K-SVD based joint dictionary and classifier learning for object recognition

This paper concerns the development of locality-preserving methods for object recognition. The major purpose is consideration of both descriptor-level locality and image-level locality throughout the recognition process. Two dual-layer locality-preserving methods are developed, in which locality-constrained linear coding (LLC) is used to represent an image. In the learning phase, the discriminative locality-preserving K-SVD (DLP-KSVD) in which the label information is incorporated into the locality-preserving term is proposed. In addition to using class labels to learn a linear classifier, the label-consistent LP-KSVD (LCLP-KSVD) is proposed to enhance the discriminability of the learned dictionary. In LCLP-KSVD, the objective function includes a label-consistent term that penalizes sparse codes from different classes. For testing, additional information about the locality of query samples is obtained by treating the locality-preserving matrix as a feature. The recognition results that were obtained in experiments with the Caltech101 database indicate that the proposed method outperforms existing sparse coding based approaches.