Multispectral Optical Finger Sensing for Artery Signal Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wearable devices struggle with accurately measuring physiological parameters due to the arbitrary nature of PPG signal acquisition, which combines signals from both superficial and major arteries, leading to inaccurate results, and traditional DOT systems are too power-consuming and complex for real-time hemodynamic imaging.
Innovation Solution
A wearable optical device using multi-wavelength PPG sensors with dual sensing modes and a neural network-based DOT system for real-time image reconstruction, capable of isolating signals from major arteries and superficial vessels, providing dynamic and static measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional PPG is used to measure blood volume changes, then the measurement can be obtained, but the signal combines contributions from both major arteries and superficial vessels leading to inaccurate results
Solution Approach 1:
The patent segments the PPG signal into distinct components by separating the signal from the major artery from the signal from superficial vessels. This is achieved by acquiring signals at multiple locations (fingertip and lower phalanx) and using signal processing to decompose the composite signal into arterial and superficial vessel contributions, allowing independent analysis of each component.
Solution Approach 2:
The patent introduces an intermediary signal processing system that acts as a mediator between the raw PPG signals and the final physiological measurements. This intermediary system uses algorithms to estimate and subtract the contribution of superficial vessels from the total signal, thereby isolating the major artery signal for accurate blood volume change measurement.
2Measurement precision
If Diffuse Optical Tomography (DOT) is used to isolate major arteries, then accurate imaging can be achieved, but the system requires significant power and has high complexity making it unsuitable for wearable devices
Solution Approach 1:
The patent extracts the essential functionality of DOT (isolating major artery signals) while removing the complex and power-intensive components. Instead of using full DOT with lasers, fiber optic cables, and CCD cameras, the invention extracts only the signal separation capability using simplified PPG sensors and computational algorithms, achieving the same physiological insight with minimal hardware complexity.
Solution Approach 2:
The patent replaces the complex mechanical/optical system of traditional DOT (lasers, fiber optics, cameras) with an electronic and computational approach. The system uses standard PPG LEDs and photodetectors combined with signal processing algorithms to achieve the same goal of isolating major artery signals, substituting heavy mechanical infrastructure with lightweight electronic processing.
3Ease of operation
If wrist-worn devices are used to obtain biosignals, then comfortable wear during daily activities is achieved, but the wrist area has deeper arteries and denser tissue reducing measurement accuracy
Solution Approach 1:
The patent segments the measurement approach by using multiple sensor locations on the finger (fingertip and lower phalanx) rather than relying on a single wrist location. This segmentation allows the system to capture signals from different tissue depths and vascular structures, compensating for the limitations of single-point measurements in dense tissue by aggregating information from multiple locations.
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
Enables accurate, real-time measurement of physiological parameters such as heart rate, blood oxygenation, and hemoglobin concentration by isolating major vessel locations, overcoming the limitations of existing technologies in accuracy and power consumption.
Implementation Method 1
A plurality of light sources disposed circumferentially about the inner surface and configured to direct light towards the appendage
Implementation Method 2
A plurality of detectors disposed circumferentially about the inner surface, each detector configured to receive light from the appendage, the light being reflected from and/or transmitted through the appendage
Implementation Method 3
multi-wavelength photoplethysmography (PPG) sensors to obtain biosignals
Implementation Method 4
the light being reflected from and/or transmitted through the appendage
Data Source
AI summary
Wearable optical devices, methods and systems for obtain dynamic and static physiological parameters from a subject are disclosed. Example devices can be worn around an appendage, such as a finger, and utilize PPG sensors to obtain signals from the appendage. The PPG sensors are positioned to acquire signals suitable to reconstruct an image of the inner appendage using, for example, diffuse optical tomography, to provide additional information. The devices, methods, and systems can obtain dynamic and static physiological parameters and accurate images in real-time.