Heart Sound Frequency Normalization for Sensor Attenuation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Healthcare systems capturing heart sounds often experience attenuation due to improper placement of sound sensors, leading to inconsistent and inaccurate representations of heart sounds, particularly affecting different frequencies of heart sounds differently.

Innovation Solution

A system and method for processing heart sounds with frequency-dependent normalization, which involves comparing a captured heart sound with a control to determine attenuation and modifying the sound accordingly to normalize it, using spectral analysis and inverse spectral analysis to produce accurate time-domain representations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sound sensors are placed on the subject to capture heart sounds, then heart sounds can be captured electronically, but attenuation occurs due to improper placement leading to inconsistent and inaccurate representations

Engineering Contradiction:
Improveaccuracy of heart sound representationVSAvoidconsistency of heart sound capture
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the captured heart sound signal through frequency-dependent normalization. The system determines attenuation characteristics across different frequency bands and applies compensatory gain adjustments to restore the original spectral balance. This transforms the degraded signal parameters back to their expected values, resolving the accuracy and consistency issues caused by sensor placement attenuation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical solution of perfect sensor placement with a signal processing solution. Instead of relying on precise physical positioning of the sound sensor, the system uses spectral analysis and frequency-dependent normalization algorithms to compensate for attenuation effects. This substitution of mechanical precision with computational correction resolves the reliability and accuracy contradictions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If frequency-dependent normalization is applied to compensate for attenuation, then accurate representation is achieved, but processing complexity increases

Engineering Contradiction:
Improveaccuracy of heart sound representationVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the heart sound signal into different frequency bands for independent analysis and normalization. By dividing the spectral content into manageable segments (frequency bins), the system can apply targeted attenuation compensation to each segment. This segmentation approach manages processing complexity by breaking down the complex normalization task into simpler, frequency-specific operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs self-service by automatically determining its own attenuation characteristics through spectral analysis of the captured signal. The algorithm identifies the attenuation profile from the signal itself and applies appropriate normalization without requiring external calibration or manual intervention. This self-service approach reduces operational complexity while maintaining high accuracy.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3831306B1Heart sound normalization
Publication Date: 2025.08.06 ANALOG DEVICES INC
  • EP3831306B1 patent drawingFigure 1
  • EP3831306B1 patent drawingFigure 2(a)~2(b)
  • EP3831306B1 patent drawingFigure 3~4

AI summary

There is disclosed herein examples of systems and methods of processing captured heart sounds with frequency-dependent normalization. Based on an amount of attenuation of a first heart sound, a second heart sound can be normalized by modifying portions of the second heart sound by amounts determined based on frequencies of the portions. Accordingly, the systems and methods disclosed herein can result in different amounts of modification of different portions of the second heart sound based on the different frequencies of the portions.