IEEE J Biomed Health Inform. 2024 May;28(5):2794-2805. doi: 10.1109/JBHI.2024.3370394. Epub 2024 May 6.
Heart rate variability (HRV) is a crucial metric that quantifies the variation between consecutive heartbeats, serving as a significant indicator of autonomic nervous system (ANS) activity. It has found widespread applications in clinical diagnosis, treatment, and prevention of cardiovascular diseases. In this study, we proposed an optical model for defocused speckle imaging, to simultaneously incorporate out-of-plane translation and rotation-induced motion for highly-sensitive non-contact seismocardiogram (SCG) measurement. Using electrocardiogram (ECG) signals as the gold standard, we evaluated the performance of photoplethysmogram (PPG) signals and speckle-based SCG signals in assessing HRV. The results indicated that the HRV parameters measured from SCG signals extracted from laser speckle videos showed higher consistency with the results obtained from the ECG signals compared to PPG signals. Additionally, we confirmed that even when clothing obstructed the measurement site, the efficacy of SCG signals extracted from the motion of laser speckle patterns persisted in assessing the HRV levels. This demonstrates the robustness of camera-based non-contact SCG in monitoring HRV, highlighting its potential as a reliable, non-contact alternative to traditional contact-PPG sensors.
心率变异性（HRV）是一个重要的指标，用于量化连续心跳之间的变化，是自主神经系统（ANS）活动的重要指标。它已广泛应用于心血管疾病的临床诊断、治疗和预防。在这项研究中，我们提出了一种用于离焦散斑成像的光学模型，以同时结合平面外平移和旋转引起的运动，实现高度敏感的非接触式心冲击图（SCG）测量。我们使用心电图（ECG）信号作为金标准，评估了光体积描记图（PPG）信号和基于散斑的 SCG 信号在评估 HRV 方面的性能。结果表明，与 PPG 信号相比，从激光散斑视频中提取的 SCG 信号测量的 HRV 参数与从 ECG 信号获得的结果更一致。此外，我们还证实，即使衣服遮挡了测量部位，从激光散斑图案的运动中提取的 SCG 信号在评估 HRV 水平方面仍然有效。这证明了基于摄像机的非接触式 SCG 在监测 HRV 方面的稳健性，突出了它作为传统接触式 PPG 传感器的可靠、非接触式替代方案的潜力。
