Pulse Wave Signal Processor Characteristic Point Alignment
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Solution Overview
Problem
Existing methods for estimating blood vessel stiffness and blood pressure from pulse wave signals often lose necessary information due to incorrect arithmetical averaging, which can result from incorrect base points in sectioned signals.
Innovation Solution
A pulse wave signal processor that includes a signal acquirer, a first filter for attenuating high-frequency components, a second filter for attenuating lower-frequency components, a characteristic-point extractor, a signal separator for partitioning signals into sections with coincident characteristic points, and an averaging calculator for correctly averaging these sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If arithmetical averaging is performed on partitioned pulse wave signal sections, then noise reduction is achieved, but the wave profile becomes broad and necessary information is lost
Solution Approach 1:
The patent applies preliminary action by extracting characteristic points (peak points, inflection points, etc.) from each pulse wave section before performing arithmetical averaging. This ensures that critical waveform features are identified and preserved in advance, allowing the averaging process to maintain these characteristic points at their correct temporal positions rather than allowing them to shift or broaden incorrectly.
Solution Approach 2:
The patent changes the parameter of base point alignment from arbitrary or fixed positioning to characteristic point-based positioning. By using extracted characteristic points as the reference for aligning sections during averaging, the method transforms the averaging process into one that preserves physiologically significant waveform features while still achieving noise reduction through the averaging of multiple aligned sections.
2Productivity
If sections are partitioned with incorrect base points, then processing can be performed, but arithmetical averaging is incorrect and estimation accuracy deteriorates
Solution Approach 1:
The patent implements feedback by using extracted characteristic points from each section to determine the correct alignment position for arithmetical averaging. The characteristic points serve as feedback signals that guide the base point selection, ensuring that sections are aligned based on their actual waveform features rather than arbitrary positions, thereby maintaining both processing efficiency and estimation accuracy.
Solution Approach 2:
The patent replaces the mechanical approach of fixed or arbitrary base point positioning with a signal-processing approach based on characteristic point extraction. Instead of mechanically aligning sections at predetermined positions, the system uses automated detection of waveform characteristics (peaks, inflection points) to dynamically determine alignment positions, substituting manual/mechanical alignment with intelligent signal-based alignment.
Data Source
AI summary
In a pulse wave signal processor, a first filter attenuates a frequency component in an acquired pulse wave signal or in a differentiated pulse wave signal, and the attenuated frequency component is more than or equal to a first frequency. A second filter attenuates a frequency component in the acquired pulse wave signal, and the attenuated frequency component is less than the first frequency and more than or equal to a second frequency. A characteristic-point extractor extracts a characteristic point that exists in each single pulse of the pulse wave signal filtered by the second filter, and a signal separator partitioning the pulse wave signal or the differentiated signal filtered by the first filter into sections such that each section includes one of the extracted characteristic points. The partitioned sections are overlapped such that the characteristic points are coincident with each other, and arithmetically averaged.