Heartbeat-Referenced Monitoring Device for PPG Pulse Estimation
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Solution Overview
Problem
Existing methods for estimating the fundamental frequency of pulse rate are prone to accuracy decreases due to body movement, leading to incorrect identification of peak frequencies.
Innovation Solution
A monitoring device and physiological signal processing device that utilize a heartbeat signal to correlate and compare with photoplethysmogram signals, estimating the fundamental frequency of pulse rate by identifying the peak frequency closest to the heart rate frequency, thereby reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency component analysis is performed on photoplethysmogram signal to estimate fundamental frequency of pulse rate, then pulse rate estimation can be obtained, but estimation accuracy decreases when body movement noise is present
Solution Approach 1:
The patent introduces a heartbeat signal as an intermediary reference to mediate the estimation of pulse rate fundamental frequency. By using the heartbeat signal's fundamental frequency as a reference point, the system can identify and select the corresponding peak frequency in the photoplethysmogram signal's frequency spectrum, even when noise is present. This intermediary approach allows accurate frequency estimation without being directly affected by body movement noise in the photoplethysmogram signal.
2Measurement precision
If multiple peak frequencies appear in photoplethysmogram signal due to noise, then frequency identification becomes complex, but simple peak detection is insufficient for accurate estimation
Solution Approach 1:
The patent implements a feedback mechanism where the fundamental frequency of the heartbeat signal serves as a reference to guide the selection of peak frequencies from the photoplethysmogram signal. The system compares the heartbeat fundamental frequency with the detected peak frequencies and selectively identifies the matching peak as the fundamental frequency of pulse rate. This feedback-based approach simplifies the complexity of multiple peak identification by providing a clear selection criterion based on physiological correlation between heartbeat and pulse.
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 method effectively prevents decreases in estimation accuracy by accurately identifying the fundamental frequency of pulse rate, even in the presence of noise from body movement, enhancing the reliability of pulse rate calculations.
Implementation Method 1
a first photoplethysmogram signal acquired by irradiating a body of a subject with a first light having a first wavelength
Data Source
AI summary
A monitoring device includes a receiving unit, a processing unit, and an information providing unit. The receiving unit is configured to receive a first photoplethysmogram signal acquired by irradiating a body of a subject with a first light having a first wavelength, and a heartbeat signal corresponding to a heartbeat of the subject. The processing unit is configured to calculate a fundamental frequency of heart rate corresponding to a heart rate of the subject based on the heartbeat signal, and estimate a fundamental frequency of pulse rate of the subject by comparing the fundamental frequency of heart rate with a frequency component of the first photoplethysmogram signal. The information providing unit is configured to provide information acquired based on the fundamental frequency of pulse rate.