Camera-Based Dual-Wavelength Defocused Speckle Imaging for Multi-Point Seismocardiographic Motion Measurement

Area of Science:

• Biomedical Optics
• Cardiovascular Physiology
• Medical Imaging

Background:

• Continuous cardiac monitoring is vital for managing cardiovascular diseases like heart failure and coronary artery disease.
• Current monitoring methods can be burdensome on healthcare systems.
• Contactless monitoring offers a promising alternative for patient care.

Purpose of the Study:

• To introduce a novel contactless method for multi-point cardiac motion monitoring using dual-wavelength defocused speckle imaging (DW-DSI).
• To demonstrate the feasibility of estimating blood pressure (BP) using multi-point seismocardiography (MP-SCG) signals.
• To evaluate the performance of DW-DSI based MP-SCG for BP estimation.

Main Methods:

• Development of a prototype DW-DSI system for contactless MP-SCG signal acquisition from atrial and ventricular regions.
• Utilizing the time delay between atrial and ventricular motion signals for BP estimation.
• Experimentation with 19 subjects under ice water stimulation, comparing MP-SCG derived BP with ECG-PPG derived pulse arrival time.

Main Results:

• BP estimation using MP-SCG time delay features showed comparable performance to ECG-PPG derived pulse arrival time.
• The best BP estimation performance was achieved using correlation features (time delay, heart rate) from MP-SCG with an artificial neural network.
• Mean absolute errors for systolic, diastolic, and mean BP were 6.954, 5.368, and 5.415 mmHg, respectively, with correlation coefficients ranging from 0.517 to 0.639.

Conclusions:

• The camera-based DW-DSI system is effective for measuring MP-SCG signals.
• The study demonstrates the feasibility of contactless, continuous blood pressure monitoring using MP-SCG.
• This technology holds potential for non-invasive cardiovascular health assessment and management.