Group Self-Paced Learning With a Time-Varying Regularizer for Unsupervised Change Detection

Abstract

Unsupervised change detection based on supervised or semisupervised classifiers has achieved strong adaptability and robustness to obtain satisfactory change detection results. However, these methods suffer from an issue that it is hard to collect reliable training samples in an unsupervised manner. In this article, a group self-paced learning (GSPL) framework is proposed to mine the reliable training samples. In the proposed method, each sample is assigned a weight to indicate its reliability. The proposed scheme is able to learn the weighted samples and update the weights iteratively in a self-paced manner to identify the reliable training samples. In the phase of updating weights, a grouping strategy is designed to avoid selecting training samples from homogeneous regions. Furthermore, a novel time-varying self-paced regularizer is proposed to automatically determine the learning scheme of self-paced learning. Finally, three classifiers, including SoftMax, backpropagation neural network, and support vector machine, are investigated under this proposed framework. Experiments on five change detection data sets demonstrate that the proposed framework can significantly outperform those state-of-art methods for change detection in terms of accuracy and robustness.