Noninvasive Optical Physiological Measurement with Motion Artifact Correction
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Solution Overview
Problem
Current noninvasive optical systems for measuring physiological properties in tissue, such as oxygenation and heart rate, are limited by motion and orientation artifacts, requiring subjects to remain still or follow specific movements, making real-time monitoring in everyday conditions challenging, especially for distinguishing between venous and arterial blood parameters.
Innovation Solution
A system combining an optical sensor with a mechanical sensor, utilizing light emitters that emit multiple wavelengths and an accelerometer to differentiate between venous and arterial blood parameters by leveraging the distinct responses of venous and arterial vascular systems to motion and orientation changes, allowing for the evaluation of venous blood properties during regular activities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noninvasive optical systems are used to measure physiological properties in tissue, then oxygenation and heart rate can be evaluated, but motion and orientation artifacts degrade measurement quality
Solution Approach 1:
The patent introduces a mechanical sensor (accelerometer) as an intermediary device that detects motion and orientation changes. This sensor acts as a mediator between the optical measurement system and the motion artifacts, providing data that is used to identify and correct artifact-contaminated measurements, thereby improving overall measurement quality without requiring the subject to remain still
Solution Approach 2:
The system implements feedback by continuously monitoring motion parameters with the accelerometer and using this information to adjust or correct the optical measurements in real-time. The processor uses the mechanical sensor data to identify when motion artifacts are present and applies corrections to maintain measurement accuracy during movement
2Measurement precision
If subjects are required to remain still during evaluation, then measurement quality improves, but real-time monitoring during everyday activities becomes impossible
Solution Approach 1:
The patent transitions from a static measurement approach (requiring subjects to remain still) to a dynamic approach that adapts to movement. By incorporating motion sensors and using algorithms that can distinguish between physiological signals and motion artifacts, the system maintains measurement quality while allowing subjects to move naturally, enabling real-time monitoring during everyday activities
3Measurement precision
If mechanical sensors are used to detect motion, then motion artifacts can be identified, but the system complexity increases
Solution Approach 1:
The patent combines the optical sensor system with a mechanical motion sensor (accelerometer) into an integrated measurement device. By merging these different sensing modalities, the system leverages the strengths of each sensor type - the optical sensor for physiological measurements and the mechanical sensor for motion detection - while sharing processing resources and data fusion algorithms, thereby managing complexity through integration rather than separate systems
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 monitoring of venous and arterial blood properties without the need for subjects to remain still, providing reliable measurements of oxygenation and heart rate variability even during movement and changes in position, enhancing the precision and convenience of physiological property assessment.
Implementation Method 1
a light emitter (46.1-46.3) capable of emitting light of at least two different wavelengths
Data Source
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AI summary
Embodiments of the present invention comprise systems and methods for noninvasive measurements of physiological properties of tissue. The system comprises a light emitter, an optical detector, a mechanical sensor and a processor. The light emitter is capable of emitting light of at least two different wavelengths and comprises at least one light source. The processor is capable of evaluating physiological properties of the tissues from measurements of the optical and the mechanical sensor. More precisely, the processor is capable of evaluating physiological properties of venous blood by using data measured by the mechanical sensor and the optical detector. For example, the oxygenation of venous blood can be measured. Furthermore, the systems can optionally comprise a light emitter which emits three wavelengths and/or the light emitter and the optical detector are arranged in reflection geometry and are located at a distance of at most 10 mm from each other.