Speaker Classification Using Neural Network MFCC Extraction

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Solution Overview

Problem

Current automated speaker recognition systems face challenges in accurately identifying and verifying speakers from audio data, particularly in noisy environments and with limited audio duration, leading to suboptimal performance in classification and verification tasks.

Innovation Solution

The implementation of a speaker classification system that extracts voiced speech frames using short-term energy and spectral centroid thresholds, computes mel-frequency cepstral coefficients, and employs a trained multi-class neural network for feature extraction and classification, with speaker-level mean-variance normalization and dynamic regularization to improve recognition scores and verification accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional speaker recognition methods are used, then the system can process audio data, but the classification accuracy and verification performance are suboptimal, especially in noisy environments and with limited audio duration

Engineering Contradiction:
Improvespeaker classification accuracyVSAvoidverification accuracy in noisy environments
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transforms the audio signal from the time domain to the frequency domain using Short-Time Fourier Transform (STFT), and further processes it through Mel-filterbank and Discrete Cosine Transform (DCT) to extract Mel-frequency cepstral coefficients (MFCCs). This series of parameter transformations converts raw audio waveforms into compact spectral feature representations that are more robust to noise and better suited for speaker classification, directly resolving the contradiction between processing capability and classification accuracy.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If more audio data is used for speaker verification, then verification accuracy improves, but the system cannot effectively identify speakers from short audio durations

Engineering Contradiction:
Improvespeaker verification accuracyVSAvoidminimum audio duration for identification
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent extracts only the most discriminative features from the audio signal by computing MFCCs and their temporal derivatives (deltas and double deltas). This extraction process isolates the essential speaker-specific characteristics from the raw audio, enabling accurate speaker identification even from short audio segments of just 1 second, while still achieving high verification accuracy with 5 seconds of data.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The transformation of audio signals into MFCC feature space concentrates speaker-specific information into a compact representation. This parameter transformation allows the system to achieve effective speaker identification from very short audio durations by focusing on the most relevant spectral-temporal features rather than requiring long audio samples.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If complex feature extraction and normalization processes are applied, then recognition scores and verification accuracy improve, but the computational complexity increases

Engineering Contradiction:
Improverecognition score accuracyVSAvoidcomputational processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies speaker-level mean-variance normalization to the MFCC features before they are fed into the neural network classifier. This preliminary normalization step standardizes the feature distribution for each speaker, improving the convergence and accuracy of the recognition model. By performing this normalization upfront, the system achieves better recognition scores without requiring overly complex real-time processing during classification.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10755718B2System and method for neural network based speaker classification
Publication Date: 2020.08.25 GENESYS CLOUD SERVICES INC
  • US10755718B2 patent drawing
  • US10755718B2 patent drawing
  • US10755718B2 patent drawing

AI summary

A method for classifying speakers includes: receiving, by a speaker recognition system including a processor and memory, input audio including speech from a speaker; extracting, by the speaker recognition system, a plurality of speech frames containing voiced speech from the input audio; computing, by the speaker recognition system, a plurality of features for each of the speech frames of the input audio; computing, by the speaker recognition system, a plurality of recognition scores for the plurality of features; computing, by the speaker recognition system, a speaker classification result in accordance with the recognition scores; and outputting, by the speaker recognition system, the speaker classification result.