Structured discriminant analysis dictionary learning for pattern classification

Dictionary learning has been widely used in the field of pattern recognition. Although the existing synthesis dictionary learning methods have achieved impressive results, they need compute sparse codes using a time-consuming sparse coding procedure. As a dual viewpoint of synthesis dictionary learning, analysis dictionary learning (ADL) has attracted much attention due to its high efficiency and intuitive meaning in recent years. However, how to associate analysis dictionary atoms with class labels and learn a structured discriminant analysis dictionary, is still a challenging problem. In this paper, we propose a structured discriminant analysis dictionary learning (SDADL) method to learn a structured discriminant analysis dictionary that consists of the class-specific analysis sub-dictionaries associated with the corresponding classes. Specifically, we introduce a classification error term into SDADL model to learn an optimal linear classifier for classification. To obtain the discriminant analysis sparse codes, we introduce a discriminant analysis sparse code error term into SDADL model, which forces the samples from the same class to have similar analysis sparse codes. Moreover, we also introduce a structured discriminant term into SDADL model to improve the discrimination capability of both each class-specific analysis sub-dictionary and analysis sparse codes. An efficient iterative algorithm is also developed to solve the optimization problem of SDADL. In addition, we design a novel scheme for classification. Extensive experiments on five image datasets verify the effectiveness of SDADL for pattern classification. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The SDADL method proposes a structured discriminant analysis dictionary learning approach to improve pattern classification by associating class-specific analysis sub-dictionaries. It introduces classification error term, discriminant analysis sparse code error term, and structured discriminant term to optimize the dictionary learning process, along with designing an efficient iterative algorithm for optimization.