Non-contact Cardiovascular Assessment via Multi-Camera Array
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Solution Overview
Problem
Traditional cardiac monitoring methods, such as electrocardiography (ECG) and contact photoplethysmography (PPG), are susceptible to motion artifacts and discomfort, limiting their suitability for long-term or repeated monitoring, especially in environments with head motion.
Innovation Solution
A non-contact imaging method using a multi-camera array captures synchronized images of a subject's face and neck, extracting Red, Green, and Blue components, and applying independent component analysis to identify cardiac signals, which are then filtered and upscaled to improve signal-to-noise ratio and reduce motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact photoplethysmography (PPG) sensors are used to monitor cardiovascular performance, then measurement of blood flow and pulse rate is achieved, but the sensor obstructs physical activity and causes discomfort for prolonged monitoring
Solution Approach 1:
The patent replaces contact-based mechanical PPG sensors with a non-contact optical imaging system using cameras and light sources. This substitution eliminates the need for physical attachment to the subject's body, thereby removing obstructions to physical activity and discomfort associated with prolonged wear, while maintaining the capability to measure cardiovascular parameters through optical detection of blood volume changes
2Duration of action of stationary object
If contact PPG sensors are used to measure pulse rate, then continuous monitoring is achieved, but motion sensitivity corrupts the collected signal when the sensor-skin interface is disturbed
Solution Approach 1:
The patent replaces contact-based PPG sensing with non-contact optical imaging that captures blood volume changes through reflected light from the skin surface. This eliminates the sensor-skin interface that is susceptible to motion artifacts, allowing continuous monitoring without signal corruption during movement or changes in subject position
Solution Approach 2:
The patent introduces multiple light sources and cameras as intermediaries to detect cardiovascular signals. The light sources illuminate the skin and the cameras capture reflected light, serving as a non-contact intermediary measurement system that avoids direct physical contact and its associated motion sensitivity problems
3Measurement precision
If ECG electrodes are affixed to the skin surface to measure cardiac activity, then accurate electrical potential measurement is achieved, but it requires time and resources for electrode application and causes potential discomfort to the subject
Solution Approach 1:
The patent replaces ECG electrode-based electrical measurement with non-contact optical imaging that detects cardiovascular activity through light reflection from the skin. This eliminates the need for electrode application, saving time and resources, while avoiding skin discomfort or sensitivity issues, though it measures different physiological parameters (optical blood volume changes vs. electrical potentials)
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate and robust non-contact cardiac assessment with reduced measurement errors, comparable to traditional contact methods, even during head motion, by increasing the dimensionality of the imager channel space and improving data quality.
Implementation Method 1
Reflection mode is most common for imaging photoplethysmography (iPPG) applications where the photoplethysmogram is derived as a net intensity, over a region of interest, observed from reflected light that is captured by an imager
Implementation Method 2
spectral components of the captured images are extracted
Data Source
AI summary
A method is provided for non-contact cardiac assessment of a subject. Images of the subject are captured from at least two synchronized independent imaging devices spaced equidistant from the subject and positioned such that each imaging device captures an image of the subject different from other imaging devices. Spectral components of the captured images are extracted. The extracted spectral components are analyzed. A signal corresponding to cardiac information is identified in the extracted spectral components. The identified signal corresponding to the cardiac information is extracted from the extracted spectral components.