Voice Activity Detection Using Multi-Feature Voting

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Solution Overview

Problem

Conventional methods for voice activity detection in voice-controlled devices are either complex and costly or sacrifice accuracy to keep costs low, making them inefficient for reliable human voice detection.

Innovation Solution

A system that extracts multiple features from audio signals using algorithms like zero-crossing detection, periodicity detection, energy ratio calculation, and envelope-to-floor determination, comparing these features to predefined criteria to generate an aggregate value for determining the presence of a human voice, thereby improving accuracy and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex algorithms are used for voice detection, then detection accuracy is improved, but device cost and implementation complexity increase

Engineering Contradiction:
Improvevoice detection accuracyVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The voice detection system segments the audio signal processing into distinct feature extraction modules (zero-crossing detection, periodicity detection, energy ratio calculation, envelope-to-floor determination) and combines their outputs through voting. This segmentation allows each module to be simple and inexpensive while collectively achieving high detection accuracy, resolving the contradiction between accuracy and complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple simple detection algorithms into a unified voice activity detection system where each algorithm processes the audio signal independently and contributes to a final vote. This combining approach achieves accuracy comparable to complex algorithms while maintaining low implementation cost, as the individual algorithms are computationally inexpensive but their collective decision is robust.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If simple algorithms are used for voice detection, then device cost is reduced, but detection accuracy deteriorates

Engineering Contradiction:
Improvealgorithm simplicityVSAvoidvoice detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines multiple simple algorithms (zero-crossing detection, periodicity detection, energy ratio calculation, envelope-to-floor determination) that individually have low computational complexity. By merging their outputs through a voting mechanism, the system achieves high detection accuracy without requiring any single complex algorithm, thus maintaining low device cost while improving accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system divides the detection task into separate simple modules, each performing a basic operation on the audio signal. This segmentation allows the use of simple algorithms throughout while achieving high overall accuracy through the collective strength of multiple simple detectors, avoiding the need for expensive complex algorithms.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If multiple feature extraction algorithms are applied to audio signals, then voice detection accuracy is improved, but processing time and computational cost increase

Engineering Contradiction:
Improvevoice detection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the audio signal into frames and applies different simple feature extraction algorithms to each frame independently. This segmentation allows parallel processing and reduces the computational burden on any single algorithm, thereby reducing overall processing time while maintaining high accuracy through the combination of multiple features.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies multiple feature extraction algorithms that may be slightly excessive for the task, but each algorithm is simple and fast. The voting mechanism then filters out redundant information. This partial/excessive action approach ensures high accuracy through multiple perspectives while keeping processing time low because each individual algorithm is computationally inexpensive.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11823706B1Voice activity detection in audio signal
Publication Date: 2023.11.21 META PLATFORMS INC
  • US11823706B1 patent drawing
  • US11823706B1 patent drawing
  • US11823706B1 patent drawing

AI summary

A method of detecting human voice activity includes determining a presence of human voice in a frame of audio signal using a plurality of features extracted from the frame of audio signal. The extracted features can include a number of zero-crossings, a periodicity metric, an energy ratio between a low frequency band and a high frequency band, and an envelope-to-floor ratio (EFR) in the frame of audio signal. Each of the features is associated with predefined criteria indicative of a presence of human voice, and based on comparisons of the features to the respective predefined criteria, the voice activity detector determines whether the frame of audio signal includes a human voice.