Source-Free Domain Adaptation for Millimeter Wave Radar Based Human Activity Recognition

Human activity recognition based on millimeter-wave radar is dedicated to monitor people’s daily activities and detect specific dangerous actions. Although existing methods achieve some improvement, they rarely consider the challenges of domain difference, such as ages and environments. To address this challenge, we propose a source-free domain adaptation method for millimeter wave radar based human activity recognition, which achieves knowledge transfer from the source domain to the target domain. Firstly, we propose balanced clustering to obtain cluster centers of source domain as the prior-knowledge through the pre-trained model. Then, in order to perform domain adaptation, the model is fine-tuned by the integration of domain adaptation and self-supervision of the target domain. Experiment results on several transfer tasks show that our proposed method is effective in human activity recognition and outperforms some other advanced transfer learning methods.