Improved Variational Mode Decomposition for Contactless Heartbeat Monitoring

In this letter, an improved variational mode decomposition (VMD) algorithm is presented for wireless signal-based heartbeat monitoring. The improved VMD algorithm restricts the central frequencies of the intrinsic mode functions (IMFs) within a coarse-scale frequency range to denoise reflected signals and extract heartbeat signals precisely. Experimental results demonstrate that the proposed VMD algorithm has achieved an accuracy of 90.72% for heartbeat frequency estimation, while the accuracy of the baseline VMD is only 82.47%. Furthermore, it is observed that the improved VMD relies on little prior knowledge and needs little manually judgment, promising for real-world applications.