Wavelet- and Cosine-Transform-Based Super-Resolution Algorithm (WCT-SRA) for Radar-Based Multi-Person Vital Sign Monitoring

This study focuses on enhancing the frequency resolution to improve the multi-person vital sign detection using a short time window. The proposed wavelet- and cosine-transform-based super-resolution algorithm (WCT-SRA) significantly improves the frequency resolution by estimating the amplitude, frequency, and initial phase of a signal using a cosine-transform-based method. Moreover, wavelet decomposition makes the decomposition process for each subject’s component more efficient. Experimental results with two actuators demonstrate that the WCT-SRA can distinguish closely spaced vibration frequencies of two metal plates and enable frequency resolutions of 0.1 Hz, 0.05 Hz, and 0.01 Hz with time windows of only 5s, 10s, and 20s, respectively. Moreover, by adjusting the initial distances of subjects from the radar, the vital signs of four individuals were simultaneously determined during a 20-s time window.