Wearable Optical Motion Artifact Correction
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Solution Overview
Problem
Existing methods for determining physiological effort during exercise, such as heart rate monitoring, are unreliable due to motion artifacts caused by the instability of sensors against the skin, leading to erroneous measurements.
Innovation Solution
A wearable apparatus with an optically sensitive detector mounted to create a detector-air interface, isolating the optical measurement from the skin and allowing only motion information to be detected, which is then used to improve the reliability of heart rate determination and physiological activity measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optically sensitive detector is placed directly against the skin to detect blood pulse, then the blood pulse detection sensitivity is improved, but motion artifacts increase and measurement reliability deteriorates
Solution Approach 1:
The patent segments the detection function into two separate detectors: one detector (first optically sensitive detector) is placed against the skin to detect blood pulse information, while another detector (second optically sensitive detector) is positioned away from the skin to detect only motion artifacts. This segmentation allows the system to separately measure and subsequently remove motion artifacts from the blood pulse signal, resolving the contradiction between detection sensitivity and measurement reliability.
Solution Approach 2:
The patent extracts the motion artifact component from the overall optical signal by using a detector positioned away from the skin surface. This second detector specifically captures motion-induced optical path changes without blood pulse contamination. The extracted motion artifact information is then used to correct the blood pulse signal, thereby improving measurement reliability while preserving detection sensitivity.
2Reliability
If the sensor is stabilized against the skin to reduce motion artifacts, then measurement reliability improves, but the detector cannot isolate motion information for correction
Solution Approach 1:
The patent introduces an intermediary detection system consisting of two optically sensitive detectors positioned at different locations. The second detector acts as an intermediary that specifically measures motion artifacts without being affected by blood pulse variations. This intermediary measurement enables the system to capture and utilize motion information for signal correction, thereby maintaining both reliability and information availability.
3Reliability
If additional sensors and processing are added to correct motion artifacts, then measurement reliability improves, but device complexity increases
Solution Approach 1:
The patent combines the blood pulse detection and motion artifact detection functions into a single integrated apparatus with two optically sensitive detectors that share common optical components and processing circuitry. This merging approach allows the system to achieve improved measurement reliability through motion artifact correction while minimizing the increase in device complexity by reusing hardware resources and integrating processing functions.
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 solution effectively reduces the impact of motion artifacts on heart rate determination, providing more accurate physiological effort measurements by isolating blood pulse information and using motion data to correct for measurement errors.
Implementation Method 1
an optically sensitive detector mounted to a wearable item and configured to detect optical signals reflected from the skin of the person
Data Source
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AI summary
There is provided a wearable item (202) configured to be placed at least partially against a skin (210) of a person (100); and an optically sensitive detector (204) mounted to the wearable item (202) and configured to detect optical signals (206) reflected from the skin (210) of the person (100), wherein the detected optical signals (206) represent a relative motion between the wearable item (202) and theskin (210) of the person (100) and wherein the optically sensitive detector (204) is mounted to the wearable item (202) such that there is a predetermined space between the optically sensitive detector (204) and the skin (210) of the person (100).