Label propagation with structured graph learning for semi-supervised dimension reduction

Abstract

Graph learning has been demonstrated as one of the most effective methods for semi-supervised dimension reduction, as it can achieve label propagation between labeled and unlabeled samples to improve the feature projection performance. However, most existing methods perform this important label propagation process on the graph with sub-optimal structure, which will reduce the quality of the learned labels and thus affect the subsequent dimension reduction. To alleviate this problem, in this paper, we propose an effective Label Propagation with Structured Graph Learning (LPSGL) method for semi-supervised dimension reduction. In our model, label propagation, semi-supervised structured graph learning and dimension reduction are simultaneously performed in a unified learning framework. We propose a semi-supervised structured graph learning method to characterize the intrinsic semantic relations of samples more accurately. Further, we assign different importance scores for the given and learned labeled samples to differentiate their effects on learning the feature projection matrix. In our method, the semantic information can be propagated more effectively from labeled samples to the unlabeled samples on the learned structured graph. And a more discriminative feature projection matrix can be learned to perform the dimension reduction. An iterative optimization with the proved convergence is proposed to solve the formulated learning framework. Experiments demonstrate the state-of-the-art performance of the proposed method. The source codes and testing datasets are available at https://github.com/FWang-sdnu/LPSGL-code.