Spectral Unmixing Successive Variational Mode Decomposition for Robust Vital Signs Detection Using UWB Radar

The evaluation of clinical status and vital signs is a crucial component of remote medical care. Radar provides a noncontact monitoring measurement without consideration of lighting or privacy. However, the multipath effect generated by multiple people gathered in a small indoor space seriously affects the detection of vital sign information. This study presents a noncontact measurement of the vital signs based on stepped-frequency continuous wave ultrawideband (SFCW-UWB) and impulse radio ultrawideband (IR-UWB) radars. In addition, this study suggests the spectral unmixing successive variational mode decomposition (SUSVMD) algorithm since the respiratory components have a probability of mixing with the heartbeat signal’s frequency. The suggested approach extracts band-limited modes through back projection and spectral unmixing optimization. The alternate direction method of multiplication is used to address the optimization problem. The experiments are conducted under two radar measurements and three subjects. The results show that the suggested method is superior and effective.