Noise Suppression Device Using Representative Power Spectrum

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Solution Overview

Problem

Conventional noise suppression devices require complex calculations and process large amounts of information, leading to underestimation of voice components and degradation in voice quality due to averaging of spectral components.

Innovation Solution

A noise suppression device that selects the power spectrum with the larger value in each group as the representative spectrum for noise suppression calculations, reducing information processing and preventing voice component underestimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional noise suppression devices average multiple power spectrum components to reduce information processing, then the amount of information to be processed is reduced, but voice components are underestimated and voice quality degrades

Engineering Contradiction:
Improveinformation processing efficiencyVSAvoidvoice quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent creates a representative power spectrum that copies the characteristics of the strongest spectral component in each frequency band. Instead of averaging all components, it selects and replicates the most significant voice component, preserving voice quality while reducing the information processing burden by working with a single representative spectrum per band.

Inventive Principle:
Principle #26Copying

2Measurement precision

If conventional noise suppression devices perform complex calculations for each power spectrum component, then noise suppression accuracy is improved, but the amount of information to be processed increases

Engineering Contradiction:
Improvenoise suppression accuracyVSAvoidinformation volume
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the frequency spectrum into multiple bands and processes each band independently by selecting only the strongest power spectrum component. This segmentation approach maintains noise suppression accuracy within each band while dramatically reducing the total information volume by eliminating redundant processing of weaker components across the entire spectrum.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If conventional noise suppression devices average spectral components to simplify processing, then device complexity is reduced, but voice components are suppressed and voice quality degrades

Engineering Contradiction:
Improvecalculation complexityVSAvoidvoice quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by treating different frequency bands differently - selecting the strongest component in each band based on its local characteristics rather than applying a uniform averaging operation across all frequencies. This preserves the unique properties of voice components in each band, maintaining voice quality while simplifying the overall device complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2546831B1Noise suppression device
Publication Date: 2020.01.15 MITSUBISHI ELECTRIC CORP
  • EP2546831B1 patent drawingFigure 1
  • EP2546831B1 patent drawingFigure 2
  • EP2546831B1 patent drawingFigure 3(a)~3(c)

AI summary

A band separating unit 5 carries out a band division of a plurality of power spectra into which an input signal is converted by a time-to-frequency converting unit 2 to combine power spectra into each subband, and a band representative component generating unit 6 defines a power spectrum having a maximum among the plurality of power spectra within each subband as a representative power spectrum. A noise suppression amount generating unit 7 calculates an amount of noise suppression for each subband by using the representative power spectrum and a noise spectrum, and a noise suppressing unit 9 suppresses the amplitudes of the power spectra according to the amount of noise suppression.