Heart Rate Detection Using Frequency Domain Analysis
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Solution Overview
Problem
Heart rate detection accuracy is compromised during motion due to interference signals from changes in the light propagation path between the skin and measurement devices, leading to inaccurate heart rate data.
Innovation Solution
A method and apparatus that acquire time-domain heart rate detection data, extract feature points, and transform data to the frequency domain as needed to filter out interference signals, improving accuracy by collecting statistics on feature data to calculate heart rate effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photoplethysmograph (PPG) is used for heart rate measurement, then heart rate detection is enabled, but measurement accuracy deteriorates during motion due to interference signals
Solution Approach 1:
The patent transforms the heart rate detection problem from the time domain to the frequency domain using Fast Fourier Transform (FFT). By analyzing the frequency spectrum of the PPG signal, the system can identify and isolate the heart rate frequency component from motion-induced interference frequencies, thereby maintaining measurement accuracy during physical activity.
Solution Approach 2:
The patent changes the analysis parameter from time-domain amplitude to frequency-domain spectral components. By examining the frequency spectrum rather than the raw time-domain signal, the system can distinguish between physiological signals (heart rate) and artifacts (motion interference) based on their characteristic frequencies, thus improving measurement precision during motion.
2Adaptability or versatility
If motion occurs during heart rate detection, then detection capability is maintained, but accuracy deteriorates due to light propagation path changes
Solution Approach 1:
The patent converts the harmful motion-induced light propagation changes into useful information by analyzing their frequency characteristics. Motion artifacts produce specific frequency patterns that can be identified and separated from the heart rate signal in the frequency domain, allowing the system to maintain accurate heart rate detection even during vigorous activity.
Solution Approach 2:
By transitioning from time-domain to frequency-domain analysis, the patent enables the system to adapt to motion conditions. The frequency representation reveals distinct patterns for heart rate versus motion artifacts, allowing accurate heart rate extraction regardless of motion intensity or type.
3Device complexity
If time-domain analysis is used for heart rate detection, then processing is simpler, but accuracy deteriorates under strong interference signals
Solution Approach 1:
The patent introduces frequency-domain analysis as an enhanced processing dimension that activates under specific conditions (strong interference). While this increases computational complexity compared to simple time-domain peak detection, it provides superior accuracy when motion artifacts are present, with the system intelligently selecting the appropriate analysis method based on signal quality.
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 solution enhances heart rate detection accuracy by distinguishing between weak and strong interference signals, using time-domain or frequency-domain analysis to isolate and correct heart rate data, resulting in more reliable heart rate calculations.
Implementation Method 1
since heart rate measurement is mostly commonly based on photoplethysmograph (PPG)
Data Source
AI summary
A heart rate detection method includes: acquiring a plurality of time-domain heart rate detection data; if the time-domain heart rate detection data includes a weak interference signal, extracting a first feature point from the time-domain heart rate detection data, and collecting statistics on feature data of the first feature point to determine time-domain heart rate detection data used in calculating heart rate; if the time-domain heart rate detection data includes a strong interference signal, transforming the time-domain heart rate detection data to a frequency domain to obtain a plurality of frequency-domain heart rate detection data, extracting a second feature point from the frequency-domain heart rate detection data, and collecting statistics on feature data of the second feature point to determine frequency-domain heart rate detection data used in calculating heart rate; and calculating the heart rate based on the time-domain or the frequency-domain heart rate detection data.