Pulse Wave Analyzer Beat-by-Beat Segmentation
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Solution Overview
Problem
Existing pulse wave analysis methods face challenges in accurately averaging pulse wave signals due to noise interference, leading to reduced accuracy in blood pressure estimation, particularly when large disturbances occur and peak positions in pulse wave signals are difficult to detect.
Innovation Solution
A pulse wave analyzer that uses feature points from ECG signals to segment and cut off pulse wave signals on a beat-by-beat basis, employing coefficients for weighting pulse wave signal pieces to enhance averaging accuracy and reduce noise influence, while adjusting the position of new pulse wave signal pieces to maximize correlation with the reference pulse wave.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse wave signals are segmented and averaged on a beat-by-beat basis using differential peaks or double differential peaks as base points, then the accuracy of blood pressure calculation is improved, but when large disturbance is caused, these peak positions cannot be detected with high accuracy, leading to reduced measurement precision and increased waveform disturbance
Solution Approach 1:
The patent introduces an intermediary signal processing step by calculating a envelope signal from the pulse wave signal and using its peak positions as base points for segmentation. This envelope signal acts as a mediator that is less sensitive to large disturbances than the original pulse wave signal, thereby enabling reliable peak detection and accurate segmentation even under noisy conditions. The envelope signal preserves the essential timing information while filtering out harmful disturbances.
2Reliability
If pulse wave signals are averaged before differentiation to obtain a high S/N ratio, then the signal quality is improved, but the waveforms become easily affected by disturbance and the accuracy of averaging is reduced when large disturbance occurs
Solution Approach 1:
The patent applies preliminary action by first determining the base points using the envelope signal before performing the segmentation and averaging operations. This preliminary determination of accurate base points ensures that subsequent averaging is performed on correctly aligned signal segments, preventing the accumulation of errors that would otherwise occur when averaging disturbed waveforms. The preliminary envelope analysis prepares the data in an optimal state for accurate averaging.
Data Source
AI summary
In a pulse wave analyzer, an ECG signal and a pulse wave signal are detected from an object to be analyzed. A plurality of feature points are extracting from the acquired ECG signal, the feature points appearing in a waveform of the ECG signal. The acquired pulse wave signal is segmented into a plurality of pulse wave signal pieces based on times at which the feature points appear. Each of the pulse wave signal pieces is segmented every heart beat. A reference pulse wave is calculated based on the plurality of pulse wave signal pieces, by multiplying the pulse wave signal pieces by coefficients and averaging the pulse wave signal pieces multiplied by the coefficients. The reference pulse wave is used to estimate the blood pressure of the object.