Adaptive Speech Equalization for Noisy Environments

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Solution Overview

Problem

Current speech enhancement systems fail to effectively improve speech intelligibility, especially in noisy environments, as they often require voicing decisions or prior knowledge of clean speech and noise levels, making them unsuitable for real-time applications.

Innovation Solution

An adaptive equalization system that automatically adjusts the spectral shape of speech signals using a digital signal processor and memory device, incorporating subband processing, signal power calculation, background noise estimation, speech intelligibility measurement, and spectral shape adjustment modules to enhance intelligibility without requiring voicing decisions or advanced noise level knowledge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If speech enhancement algorithms are used to suppress background noise, then noise reduction is improved, but speech intelligibility improvement is limited and voicing decisions become difficult in noisy environments

Engineering Contradiction:

Improvebackground noise suppressionVSAvoidvoicing decision difficulty

Core Design Contradiction:

Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

The patent extracts the speech intelligibility improvement function from traditional speech enhancement systems that rely on voicing decisions. By separating the spectral shape adjustment from noise suppression and making it independent of voicing detection, the system achieves intelligibility improvement without being constrained by difficulty in making voicing decisions in noisy environments

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system uses the noisy speech signal itself to determine spectral shape adjustments rather than requiring external knowledge of clean speech or noise levels. The spectral shape is derived directly from the input signal characteristics, enabling the system to serve itself without additional training or prior information

Inventive Principle:

Principle #25Self-service

2Reliability

If algorithms requiring voicing decisions or clean speech knowledge are used, then speech enhancement may be achieved, but real-time application suitability is reduced

Engineering Contradiction:

Improvespeech enhancement effectivenessVSAvoidreal-time application suitability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent pre-establishes target spectral shapes representing ideal speech characteristics before processing. These target shapes are used as reference templates to guide the equalization process, allowing the system to quickly compare and adjust the noisy speech signal without requiring complex real-time analysis or training

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical/complex process of voicing detection and clean speech estimation with a simpler spectral shape comparison approach. By substituting the complex decision-making system with a direct spectral matching system, real-time processing becomes feasible while maintaining enhancement effectiveness

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If traditional equalization curves are tuned for specific environments, then sound quality is improved for that environment, but adaptability to different environments is lost

Engineering Contradiction:

Improvesound quality tuningVSAvoidenvironmental adaptability

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent transforms static equalization curves into dynamic, adaptive spectral shapes. Instead of fixed equalization settings for specific environments, the system continuously adapts the spectral shape targets based on the characteristics of the input speech signal and environmental conditions, allowing the same system to optimize performance across varying environments

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the fundamental parameter from fixed equalization frequency responses to adaptive spectral shapes. By modifying the target representation from static frequency curves to dynamic spectral templates that can be adjusted based on signal characteristics, the system achieves both precise tuning and environmental adaptability

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9536536B2Adaptive equalization system

Publication Date: 2017.01.03 MALIKIE INNOVATIONS LTD

AI summary

An adaptive equalization system that adjusts the spectral shape of a speech signal based on an intelligibility measurement of the speech signal may improve the intelligibility of the output speech signal. Such an adaptive equalization system may include a speech intelligibility measurement module, a spectral shape adjustment module, and an adaptive equalization module. The speech intelligibility measurement module is configured to calculate a speech intelligibility measurement of a speech signal. The spectral shape adjustment module is configured to generate a weighted long-term speech curve based on a first predetermined long-term average speech curve, a second predetermined long-term average speech curve, and the speech intelligibility measurement. The adaptive equalization module is configured to adapt equalization coefficients for the speech signal based on the weighted long-term speech curve.