Channel-Compensated Features for Speaker Recognition

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Solution Overview

Problem

Conventional speaker recognition systems face challenges in accurately identifying speakers due to channel variability, noise interference, and equipment differences between enrollment and testing, leading to verification/identification errors.

Innovation Solution

A system using progressive neural networks that apply direct deep neural networks (DNNs) to raw audio signals, incorporating an acoustic channel simulator and a second CNN for speaker-aware features, to generate channel-compensated low-level features robust against noise and equipment variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional speaker recognition systems use universal background models with channel compensation techniques, then speaker recognition capability is provided, but channel variability and noise interference corrupt the signal and reduce recognition accuracy

Engineering Contradiction:
Improvespeaker recognition accuracyVSAvoidchannel variability and noise interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system segments the feature extraction process into two distinct pathways: a first CNN processes degraded speech signals to extract channel-robust features, while a second CNN processes clean speech signals to extract speaker-specific features. This segmentation allows the system to separately handle channel compensation and speaker recognition tasks, preventing channel variability from corrupting the speaker identification process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism by using the first CNN as a channel compensation module that processes degraded speech signals and generates channel-robust features. These features serve as an intermediary representation that has been cleansed of channel effects before being combined with speaker-specific features from the second CNN, thereby mediating the harmful effects of noise and channel variability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the system processes degraded speech signals through a first CNN to extract channel-robust features, then channel mismatch is reduced, but device complexity increases

Engineering Contradiction:
Improverobustness to channel variabilityVSAvoidsystem architecture complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system extracts and isolates the channel compensation function into a separate first CNN module that processes only degraded speech signals. This extraction allows the channel robustness processing to be handled independently from the speaker recognition module, making the overall system architecture more modular and manageable despite the increased complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The first CNN is designed as a universal channel compensation module that can process any degraded speech signal regardless of the specific channel conditions or noise type. This multi-functionality allows a single module to handle various channel variabilities (different phones, microphones, environments) without requiring separate processing paths for each condition, thereby managing complexity through generalization.

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

3Measurement precision

If a second CNN is added for speaker-aware features, then speaker recognition accuracy is improved, but computational cost increases

Engineering Contradiction:
Improvespeaker identification accuracyVSAvoidcomputational energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The second CNN is designed to process only clean speech signals and focus exclusively on extracting speaker-specific features, rather than handling both channel and speaker variations. This localization of function allows the second CNN to be optimized for speaker recognition specifically, improving accuracy while keeping computational requirements focused and manageable.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system performs preliminary channel compensation through the first CNN before the second CNN processes the speech signal for speaker recognition. This preliminary action removes channel variability and noise interference in advance, so the second CNN receives pre-processed, cleaner input that requires less computational effort to extract accurate speaker features, thereby reducing the overall computational burden.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3516652B1Channel-compensated low-level features for speaker recognition
Publication Date: 2022.09.07 PINDROP SECURITY INC
  • EP3516652B1 patent drawingFigure 1
  • EP3516652B1 patent drawingFigure 2A
  • EP3516652B1 patent drawingFigure 2B

AI summary

A system for generating channel-compensated features of a speech signal includes a channel noise simulator that degrades the speech signal, a feed forward convolutional neural network (CNN) that generates channel-compensated features of the degraded speech signal, and a loss function that computes a difference between the channel-compensated features and handcrafted features for the same raw speech signal. Each loss result may be used to update connection weights of the CNN until a predetermined threshold loss is satisfied, and the CNN may be used as a front-end for a deep neural network (DNN) for speaker recognition/verification. The DNN may include convolutional layers, a bottleneck features layer, multiple fully-connected layers and an output layer. The bottleneck features may be used to update connection weights of the convolutional layers, and dropout may be applied to the convolutional layers.