Adaptive Voice Activity Detection Threshold Adjustment

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Solution Overview

Problem

Conventional voice activity detection (VAD) algorithms are not adaptive to background noise variations, leading to inaccurate judgments and wastage of bandwidth.

Innovation Solution

A VAD device and method that includes a background analyzing unit to identify noise features, a VAD threshold adjusting unit to calculate a bias for the VAD threshold based on noise variation parameters, and a VAD judging unit to modify the threshold for accurate noise judgment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed VAD threshold is used based on long-term background noise average, then the algorithm is simple to implement, but it cannot adapt to background noise variations leading to inaccurate judgment

Engineering Contradiction:
Improveadaptability to background noise variationVSAvoidalgorithm complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the VAD threshold adjustable and adaptive to changing background noise conditions. The threshold is no longer fixed but dynamically modified based on short-term noise analysis, allowing the system to adapt to noise variations while maintaining reasonable complexity through structured adjustment mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the threshold parameter based on background noise characteristics. By analyzing short-term noise energy and comparing it with long-term averages, the system modifies the VAD threshold parameter to match current noise conditions, thereby improving adaptability without requiring complete redesign of the algorithm.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the VAD threshold is adjusted to be adaptive to background noise, then judgment accuracy improves, but the algorithm complexity increases

Engineering Contradiction:
Improvevoice activity judgment accuracyVSAvoidthreshold adjustment mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by pre-calculating and storing long-term background noise averages before actual voice activity detection. This preparation allows the adaptive threshold mechanism to work more efficiently during real-time operation, as the baseline noise level is already established, reducing the computational burden during critical detection phases.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring short-term noise energy and using this information to adjust the VAD threshold. The system feeds back the noise analysis results to modify the threshold, creating a closed-loop adaptive mechanism that improves judgment accuracy while managing complexity through iterative refinement.

Inventive Principle:
Principle #23Feedback

3Loss of energy

If background noise is not accurately distinguished from voice signals, then bandwidth is wasted by encoding noise frames, but increasing VAD stringency may cause false negative detections

Engineering Contradiction:
Improvetransmission bandwidth usageVSAvoidvoice signal detection reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the decision parameter (VAD threshold) based on background noise characteristics. By adjusting the threshold according to short-term noise analysis, the system can dynamically adapt its sensitivity, allowing it to be more lenient in high-noise conditions to avoid false negatives while being more stringent in low-noise conditions to save bandwidth.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8275609B2Voice activity detection
Publication Date: 2012.09.25 DOLBY INTERNATIONAL AB
  • US8275609B2 patent drawing
  • US8275609B2 patent drawing
  • US8275609B2 patent drawing

AI summary

A voice activity detection (VAD) device and method provide for a VAD threshold that is adaptive to background noise variation.