Oxygen Saturation Measurement Using Motion Artifact Filtering
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Solution Overview
Problem
Conventional non-invasive oxygen saturation measurement methods face challenges in accurately measuring oxygen saturation in mobile environments due to noise from external light sources and motion artifacts, leading to degraded accuracy and unreliable peak and valley detection.
Innovation Solution
An oxygen saturation measuring apparatus and method that includes a sensor to detect motion, a light emitter to emit light of different wavelengths, and a processor to filter frequency components corresponding to motion, allowing for the detection of pulse frequency and separation of signal components to determine oxygen saturation, even in noisy environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-invasive light absorption method is used to measure oxygen saturation, then patient comfort and real-time measurement are improved, but measurement precision deteriorates due to external light noise and motion artifacts
Solution Approach 1:
The patent converts the harmful motion artifacts and external light interference into useful information by using a motion sensor to detect motion states. The system then uses this motion information to selectively filter or correct the light absorption signals, transforming the previously harmful motion-induced noise into a basis for signal correction and improving measurement accuracy during movement.
Solution Approach 2:
The patent introduces a motion sensor as an intermediary device that detects motion artifacts separately. This intermediary sensor provides motion state information that is used to process and correct the optical measurement signals, acting as a mediator between the physical motion and the optical measurement system to improve accuracy without compromising patient comfort.
2Productivity
If peak and valley detection method is used in pulse wave signal, then oxygen saturation can be calculated, but measurement precision deteriorates when signal to noise ratio is low due to external light and motion interference
Solution Approach 1:
The patent transforms the harmful effect of motion artifacts on peak-valley detection into a beneficial process by using motion sensor data to identify and correct signal distortions. The system uses the detected motion patterns to adjust the peak and valley detection algorithm, converting previously harmful noise into information that improves detection accuracy during real-time calculation.
Solution Approach 2:
The patent dynamically changes the detection parameters of the peak and valley detection algorithm based on the detected motion state. When motion is detected, the system adjusts detection thresholds, time windows, or filtering parameters to accommodate the altered signal characteristics, maintaining accurate oxygen saturation calculation despite varying signal quality conditions.
3Ease of operation
If reflection type sensor is used on body surface like wrist watch, then ease of operation is improved, but measurement precision deteriorates due to poor contact state and low signal to noise ratio during motion
Solution Approach 1:
The patent uses a motion sensor as an intermediary to compensate for the poor contact state inherent in reflection-type sensors. By detecting motion artifacts separately, the system can distinguish between signal changes caused by motion and those caused by blood flow, maintaining accurate measurements even when physical contact between sensor and skin is inconsistent during movement.
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 more accurate and robust measurement of oxygen saturation in mobile environments by filtering out motion artifacts and external noise, improving the accuracy of pulse frequency detection and oxygen saturation determination.
Implementation Method 1
a non-invasive method of measuring light absorption when hemoglobin in blood is combined with oxygen and light absorption when hemoglobin is not combined with oxygen
Implementation Method 2
converting light that is not absorbed into the sample into an electrical signal
Implementation Method 3
a sensor configured to detect motion of the oxygen saturation measuring apparatus
Implementation Method 4
a processor configured to filter a frequency component corresponding to the detected motion in the signal
Data Source
AI summary
An oxygen saturation measuring apparatus is provided. The oxygen saturation measuring apparatus includes a sensor configured to detect motion of the oxygen saturation measuring apparatus, a light emitter comprising light emitting circuitry configured to emit light to a target subject, a light receiver comprising light receiving circuitry configured to receive one or more of light reflected by the target subject or light transmitted through the target subject to generate a signal, and a processor configured to filter a frequency component corresponding to the detected motion in the signal, to detect a pulse frequency from the filtered signal, and to determine oxygen saturation of the target subject using the filtered signal and the detected pulse frequency.