Adaptive Filtering for Pulse Signal Correction

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Solution Overview

Problem

Existing methods for determining physiological parameters, such as blood pressure, often suffer from measurement errors due to the influence of reflected pulse pressure waves, which are not effectively compensated for by rigid filtering techniques.

Innovation Solution

The method involves generating a corrected pulse measurement signal through adaptive filtering with a dynamically adapting filter characteristic, specifically breaking down the recorded signal into heartbeat sections and using adaptive low-pass filtering to compensate for the reflected component, allowing for precise correction based on prevailing physiological conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rigid filtering techniques are used to remove reflected pulse pressure waves, then the filtering process is simple and stable, but measurement precision deteriorates due to inability to effectively compensate for reflected components

Engineering Contradiction:
Improvemeasurement precisionVSAvoidfiltering complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from rigid, static filtering to adaptive filtering where filter characteristics dynamically adjust based on signal conditions. The filtering process continuously adapts its parameters to match the prevailing physiological conditions and signal characteristics, enabling effective compensation of reflected pulse pressure waves while maintaining measurement precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying filter characteristics (such as cutoff frequencies, filter orders, or other parameters) based on the analyzed signal properties. The filtering parameters are not fixed but are adjusted according to the detected signal conditions, allowing the system to optimally compensate for reflected components under varying physiological states.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If adaptive filtering with dynamically adapting filter characteristic is used, then measurement precision improves by effectively compensating for reflected components, but device complexity increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidfiltering complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by implementing a self-adjusting filtering system that automatically adapts its characteristics based on the input signal properties. The filtering algorithm monitors the signal conditions and autonomously modifies its parameters without external intervention, enabling the system to maintain optimal performance across varying physiological conditions while compensating for reflected pulse pressure waves.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If signal processing is performed for each heartbeat section, then measurement precision improves through precise localized correction, but processing time increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies segmentation by dividing the continuous pulse pressure signal into discrete heartbeat sections or beats. Each segment is independently processed through adaptive filtering to remove reflected components, allowing precise localized correction tailored to each cardiac cycle's specific characteristics while enabling parallel or sequential processing efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic action by applying the adaptive filtering process repeatedly at regular intervals corresponding to each heartbeat. This periodic processing approach allows the system to maintain continuous monitoring and correction of reflected components while synchronizing computational efforts with the natural rhythm of the cardiac cycle, optimizing processing efficiency.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3071098B1Method and device for determining at least one physiological parameter using a corrected pulse measurement signal
Publication Date: 2017.09.27 KUCHLER GERT
  • EP3071098B1 patent drawingFigure 1
  • EP3071098B1 patent drawingFigure 2
  • EP3071098B1 patent drawingFigure 3

AI summary

The method is used to determine at least one physiological parameter (P) of a patient (2). A pulse measurement signal (PM) of a pulse pressure wave, which propagates within the blood vessels starting from the heart, is detected at a pulse measurement point (15). A corrected pulse measurement signal (PK) is generated from the detected pulse measurement signal (PM) by means of signal processing. The at least one physiological parameter (P) is determined with the aid of the corrected pulse measurement signal (PK). To generate the corrected pulse measurement signal (PK), the detected pulse measurement signal (PM) is subjected to adaptive filtering using a dynamically adjusting filter characteristic in order to compensate for the influence of a reflected proportion of the pulse pressure wave.