Adaptive Noise Filter Coefficient Reduction

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Solution Overview

Problem

Existing speech processing systems face high computational and memory costs, along with poor adaptation to sampling rates, when reducing noise signals using techniques like spectral subtraction and neural networks.

Innovation Solution

An adaptive filter system with two stages, using a learning rule to continuously reduce coefficient values, implemented with a FIR filter and a second filter for sustained noise reduction, significantly reduces computational and memory requirements while allowing for efficient adaptation to different sampling rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If spectral subtraction is used to reduce noise signals, then noise reduction is achieved, but computational cost and memory requirement increase significantly

Engineering Contradiction:
Improvenoise signalsVSAvoidcomputational cost
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts only the essential information needed for noise reduction by using a simplified filter model that processes only the most relevant signal components. Instead of processing the complete spectral representation, the system uses a reduced-order model that captures the fundamental noise characteristics, thereby lowering computational requirements while maintaining effective noise suppression.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simplified filter structure with fewer coefficients that can be quickly updated and discarded. The filter uses a reduced number of parameters that are easier and faster to compute, replacing the complex spectral subtraction method with a more efficient algorithm that achieves comparable noise reduction with lower computational cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If spectral subtraction is used to reduce noise signals, then noise reduction is achieved, but memory requirement increases significantly

Engineering Contradiction:
Improvenoise signalsVSAvoidmemory requirement
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential information needed for noise reduction by using a simplified filter model that processes only the most relevant signal components. Instead of processing the complete spectral representation, the system uses a reduced-order model that captures the fundamental noise characteristics, thereby lowering computational requirements while maintaining effective noise suppression.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If spectral subtraction parameters are adapted, then noise reduction is improved, but adaptation to other sampling rates becomes difficult

Engineering Contradiction:
Improvenoise signalsVSAvoidadaptation to sampling rates
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent designs a filter model that is universally applicable across different sampling rates. The simplified filter structure uses normalized coefficients and a general form that can be adapted to various sampling frequencies without requiring complete parameter reconfiguration. This universal design allows the same filter architecture to function effectively at different sampling rates, improving adaptability while maintaining noise reduction performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Object-affected harmful factors

If complex filtering techniques are used to reduce noise, then noise reduction is achieved, but processing time increases

Engineering Contradiction:
Improvenoise signalsVSAvoidprocessing time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent extracts only the essential information needed for noise reduction by using a simplified filter model that processes only the most relevant signal components. Instead of processing the complete spectral representation, the system uses a reduced-order model that captures the fundamental noise characteristics, thereby lowering computational requirements while maintaining effective noise suppression.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simplified filter structure with fewer coefficients that can be quickly updated and discarded. The filter uses a reduced number of parameters that are easier and faster to compute, replacing the complex spectral subtraction method with a more efficient algorithm that achieves comparable noise reduction with lower computational cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS7822602B2Adaptive reduction of noise signals and background signals in a speech-processing system
Publication Date: 2010.10.26 ENTROPIC COMM INC
  • US7822602B2 patent drawing
  • US7822602B2 patent drawing
  • US7822602B2 patent drawing

AI summary

An audio input signal is filtered using an adaptive filter to generate a prediction output signal with reduced noise, wherein the filter is implemented using a plurality of coefficients to generate a plurality of prediction errors and to generate an error from the plurality of prediction errors, wherein the absolute values of the coefficients are continuously reduced by a plurality of reduction parameters.