Physiological Signal Feature Extraction Using Template Pulse Matching
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Solution Overview
Problem
Photoplethysmography signals are susceptible to external noise interference, particularly motion and ambient light, which affects the accuracy of blood pressure measurement, especially when the sensor is not properly attached to the earlobe, leading to scattered light and noise reception.
Innovation Solution
A physiological signal feature extraction method and device that filters and processes signals by determining correlated pulses, creating a template pulse through averaging, and performing match comparisons to extract features from well-shaped pulses, thereby improving signal analysis accuracy and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sensor is not properly attached to the earlobe, then the device is easier to wear, but light scatters and noise is received, reducing measurement accuracy
Solution Approach 1:
The patent applies preliminary action by performing template pulse creation and waveform matching before final measurement analysis. The system pre-establishes a reference template from initial pulses and uses it to identify and filter abnormal waveforms in subsequent measurements, ensuring accurate measurements even when wearing conditions vary
Solution Approach 2:
The patent uses template pulse matching as an intermediary mechanism between raw signal acquisition and final measurement. The template serves as a reference standard that mediates the comparison process, allowing the system to distinguish between acceptable variations in wearing conditions and actual abnormal waveforms that need filtering
2Device complexity
If traditional signal processing is used without waveform screening, then the processing is simpler, but abnormal waveforms and noise reduce signal analysis accuracy
Solution Approach 1:
The patent applies segmentation by dividing the signal processing into distinct stages: initial pulse acquisition, template creation, waveform-by-waveform matching comparison, and selective filtering. This segmented approach systematically identifies and removes abnormal waveforms while preserving valid data, improving accuracy without overwhelming complexity
Solution Approach 2:
The patent implements partial action by applying template matching and filtering only to specific pulses that deviate from the established template, rather than processing every single pulse equally. This selective approach focuses computational resources on identifying and removing abnormal waveforms while maintaining efficiency
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 enhances the accuracy of blood pressure measurement by filtering out abnormal waveforms and noise, ensuring that only well-shaped pulses are used for analysis, resulting in more reliable physiological signal extraction and improved signal-to-noise ratio.
Implementation Method 1
The light-emitting diodes emit light, and the photodiodes receive light signals passing through vessels
Data Source
AI summary
A physiological signal feature extraction method includes receiving a physiological signal, determining in a situation that a second pulse in a plurality of pulses of the physiological signal being correlated to a first pulse in the plurality of pulses, selecting the second pulse as one of a plurality of reference pulses in a reference waveform sequence after the second pulse is determined as correlated to the first pulse, averaging the plurality of reference pulses into a template pulse, performing match comparison on the plurality of pulses by the template pulse one by one, and extracting a plurality of features from each of the plurality of pulses that matches the template pulse.