Pulse Measurement Device with Motion-Adaptive Peak Detection
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Solution Overview
Problem
Existing pulse measurement devices struggle to accurately measure pulse rate during physical activity due to body motions interfering with signal detection, leading to erroneous peak detection and incorrect pulse rate calculations.
Innovation Solution
A pulse measurement device that includes a body motion level determination unit and a peak detection module, which adjusts the peak searching range based on the subject's body motion level, ensuring accurate pulse rate measurement by narrowing the search range during increased motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed peak searching range is used in Fourier-transformed spectrum analysis, then the device complexity is low and operation is simple, but measurement precision deteriorates when body motion frequency components exceed pulse wave frequency components
Solution Approach 1:
The patent applies dynamics by making the peak searching range variable rather than fixed. The peak detection unit dynamically adjusts the upper and lower limit frequencies of the searching range based on the detected body motion frequency, allowing the system to adapt to different motion conditions and maintain measurement accuracy during physical activity.
Solution Approach 2:
The patent changes the parameter of the peak searching range (specifically the frequency limits) based on the body motion frequency. By setting the upper limit to a value lower than the body motion frequency and adjusting the searching range accordingly, the system excludes motion-related frequency components from the peak detection, thereby improving measurement precision.
2Measurement precision
If the peak searching range is narrowed to exclude body motion frequencies, then measurement precision improves during exercise, but the device must determine body motion level adding system complexity
Solution Approach 1:
The patent segments the frequency spectrum into different ranges based on body motion frequency. By dividing the frequency domain and setting appropriate upper and lower limits for the peak searching range, the system isolates the pulse wave frequency components from body motion frequency components, enabling accurate pulse detection even during exercise.
Solution Approach 2:
The patent introduces body motion frequency detection as an intermediary step. The body motion frequency is detected first, and this information serves as a basis for determining the appropriate peak searching range. This intermediary measurement allows the system to adaptively adjust the detection parameters and maintain accuracy under varying motion conditions.
3Adaptability or versatility
If a wide peak searching range is used to capture all possible pulse frequencies, then adaptability is high, but erroneous peak detection increases when body motion frequencies are present
Solution Approach 1:
The patent applies dynamics by making the peak searching range variable rather than fixed. The peak detection unit dynamically adjusts the upper and lower limit frequencies of the searching range based on the detected body motion frequency, allowing the system to adapt to different motion conditions and maintain measurement accuracy during physical activity.
Solution Approach 2:
The patent changes the parameter of the peak searching range (specifically the frequency limits) based on the body motion frequency. By setting the upper limit to a value lower than the body motion frequency and adjusting the searching range accordingly, the system excludes motion-related frequency components from the peak detection, thereby improving measurement precision.
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 effectively reduces erroneous pulse rate detection caused by body motion noise, allowing for precise measurement of pulse rate even during physical activity by dynamically adjusting the peak searching range.
Implementation Method 1
a pulse wave detection signal generating unit that generates a pulse wave detection signal based on a detection signal output from the light sensor
Data Source
AI summary
It is possible to measure a pulse rate correctly, when a body moves. A frequency analysis unit 13 generates a pulse wave frequency signal by converting pulse wave detection signals detected by a light sensor 20 into a frequency domain signal from time domain signals. A body motion level determination unit 14 determines a body motion level of a subject based on acceleration detection signals output by an accelerometer 21. A peak detection unit 15 detects a peak of spectrum intensity in the pulse wave frequency signal within a peak searching range, which varies depending on the determined body motion level. A pulse calculation processing unit 16 generates pulse information based on a frequency position of the peak detected by the peak detection unit 15.