Physiological Measurement System Automatic Wavelength Adjustment
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Solution Overview
Problem
Existing physiological measurement systems face challenges in maintaining accurate readings due to variations in tissue thickness, emitter intensity, and detector sensitivity, particularly when signal quality is insufficient to support the use of a full set of wavelengths.
Innovation Solution
A physiological measurement system that automatically adjusts the number of wavelengths used based on sensor signal quality, performing calibration processes to determine if the signal quality is sufficient to support the full set of wavelengths, and switching to a reduced number of wavelengths if necessary, such as using only 660 nm and 905 nm for SpO2 readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a full set of wavelengths is used for physiological measurement, then measurement precision is improved, but device complexity increases and reliability decreases when signal quality is insufficient
Solution Approach 1:
The system dynamically adjusts the number of wavelengths used in measurement based on real-time signal quality assessment. During calibration, the system tests signal quality at each wavelength and automatically selects the optimal subset (2, 4, or 8 wavelengths) to maintain measurement accuracy while adapting to varying signal conditions, thereby resolving the contradiction between precision and complexity
Solution Approach 2:
The system changes the parameter of wavelength count based on signal quality metrics. By evaluating signal quality during calibration and adjusting the number of active wavelengths accordingly, the system maintains measurement precision when signal quality is high while reducing complexity when signal quality degrades, effectively resolving the technical contradiction
2Measurement precision
If a full set of wavelengths is used for physiological measurement, then measurement precision is improved, but reliability deteriorates when signal quality is insufficient
Solution Approach 1:
The system incorporates feedback mechanisms that continuously monitor signal quality during calibration and operation. Based on this feedback, the system automatically adjusts the number of wavelengths used, ensuring reliable measurements by preventing the use of insufficient quality signals, thus resolving the contradiction between precision and reliability
Solution Approach 2:
The system performs preliminary calibration and signal quality assessment before actual measurement. By evaluating signal quality in advance and selecting the appropriate wavelength subset during calibration, the system ensures that only reliable measurement configurations are used, resolving the contradiction between achieving precision and maintaining reliability
3Adaptability or versatility
If automatic wavelength adjustment is implemented, then adaptability is improved, but device complexity increases
Solution Approach 1:
The system segments the wavelength set into different subsets (2, 4, or 8 wavelengths) based on signal quality. By dividing the full wavelength set into manageable segments and selecting appropriate segments during calibration, the system achieves adaptability to different signal conditions while keeping the complexity of individual segments manageable, thus resolving the contradiction between adaptability and device complexity
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
The system ensures reliable and accurate physiological measurements by dynamically adjusting the number of wavelengths based on signal quality, thereby maintaining measurement accuracy even in conditions where the full set of wavelengths cannot be used.
Implementation Method 1
the sensor has light emitting diodes (LEDs) that transmit optical radiation of red and infrared wavelengths into a tissue site
Implementation Method 2
The theoretical basis of this technique is the Beer-Lambert law, which states that the concentration ci of an absorbent in solution can be determined by the intensity of light transmitted through the solution
Implementation Method 3
a detector that responds to the intensity of the optical radiation after absorption (e.g., by transmission or transreflectance) by pulsatile arterial blood flowing within the tissue site
Data Source
AI summary
Disclosed herein is a physiological measurement system that can automatically adjust the number of wavelengths used based on the quality of a sensor signal that is reflective of an optical radiation detected at a sensor after tissue attenuation. The signal quality is examined to determine if it is sufficient to support the use of a full set of wavelengths. If it is determined to be insufficient to support the full set, a reduced number of wavelengths is used.