Contactless Monitoring Of Human Vitals: A Study With Simultaneous Measurements Using FMCW Radar And Thermal Camera.

Area of Science:

• Biomedical Engineering
• Signal Processing
• Medical Imaging

Background:

• Contactless monitoring of vital signs like heart rate (HR) and breath rate (BR) is crucial for patient comfort and continuous observation.
• Existing methods may face limitations due to movement artifacts or environmental changes.
• Integrating multiple sensing modalities can potentially overcome individual sensor weaknesses.

Purpose of the Study:

• To develop and validate a contactless system for simultaneous HR and BR monitoring.
• To evaluate the performance of Frequency Modulated Continuous Wave (FMCW) radar and thermal imaging for vital sign detection.
• To introduce a Signal Quality Metric (SQM) for assessing measurement quality and enabling sensor fusion.

Main Methods:

• Utilized FMCW radar to capture body movement signals, applying Non-negative Matrix Factorization (NMF) and Wavelet analysis for HR/BR estimation.
• Employed thermal imaging to track nostril and forehead regions for BR and HR estimation.
• Conducted experiments with 50 subjects, validating results against pulse oximetry and visual camera-based abdominal movement analysis.

Main Results:

• Both radar and thermal imaging provided simultaneous HR and BR measurements.
• Identified signal degradation factors for radar (Random Body Movements) and thermal imaging (temperature fluctuations, sweating, occlusion).
• Developed an SQM to quantify measurement quality, demonstrating its utility for sensor fusion.

Conclusions:

• Combining FMCW radar and thermal camera offers a robust approach to contactless vital sign monitoring.
• The SQM-based sensor fusion strategy enhances system reliability, especially in challenging conditions.
• This integrated system holds significant clinical relevance for continuous and comfortable patient monitoring.