Through the wall human heart beat detection using single channel CW radar

Area of Science:

• Microwave Engineering
• Biomedical Engineering
• Signal Processing

Background:

• Single-channel continuous wave (CW) radar offers a simple, cost-effective solution for target detection but lacks range and angular information.
• Through-the-wall life sign detection is crucial for applications like search and rescue, with existing research often relying on complex multi-channel radar systems.
• Current methods for through-the-wall vital signs monitoring face challenges in accuracy and concurrent subject detection.

Purpose of the Study:

• To propose and validate a novel through-the-wall vital signs detection system using a single-channel 24-GHz CW radar.
• To demonstrate the capability of extracting heart rate from single and concurrent subjects through various barriers.
• To leverage the Maximal Overlap Discrete Wavelet Transform (MODWT) for enhanced signal processing and heartbeat waveform isolation.

Main Methods:

• Utilized a single-channel 24-GHz CW radar system for non-invasive vital signs detection.
• Applied the Maximal Overlap Discrete Wavelet Transform (MODWT) to process radar signals and extract heartbeat information.
• Conducted experiments with multiple subjects at varying distances (20-100 cm) through wood and brick walls, comparing results with Biopac ECG data.

Main Results:

• Achieved an average heart rate extraction accuracy of 95.27% for single subjects at distances up to 100 cm through different barriers.
• Successfully isolated independent heartbeat waveforms for two concurrent subjects with 97.04% accuracy at a 40 cm distance.
• The MODWT method outperformed the direct Fast Fourier Transform (FFT) method for single-subject detection beyond 40 cm.

Conclusions:

• The proposed single-channel CW radar system, enhanced with MODWT, provides an accurate and simplified approach for through-the-wall vital signs monitoring.
• This technology demonstrates significant potential for real-time detection of individuals in disaster scenarios, security surveillance, and patient monitoring.
• The ability to detect concurrent heartbeats without range or angular estimation offers a unique advantage for practical through-the-wall applications.