Neural Network Acoustic Model Side Task Prediction

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Solution Overview

Problem

Conventional automatic speech recognition (ASR) systems lack robustness when processing utterances in noisy environments, as they are typically trained to recognize specific noise patterns and fail to perform well in different acoustic interference conditions.

Innovation Solution

Neural network acoustic models are trained using source-separation-style training, which involves producing side task outputs to isolate speech and interference components of an audio signal, and updating parameters with a weighted composite of loss functions to enhance recognition accuracy in noisy conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional ASR systems are trained to recognize specific noise patterns, then recognition accuracy for those specific patterns improves, but robustness in different acoustic interference conditions deteriorates

Engineering Contradiction:
Improverecognition accuracyVSAvoidrobustness in different acoustic conditions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The audio signal is segmented into separate speech and interference components through side task prediction outputs. The neural network produces distinct predictions for speech signals and interference signals, allowing the system to process each component separately rather than treating the mixed signal as a whole, thereby improving robustness across different acoustic conditions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The neural network acoustic model is designed to perform multiple functions simultaneously: it processes the mixed audio signal for speech recognition while also producing side task outputs that predict separate speech and interference components. This multi-functional approach enables the system to adapt to various acoustic interference conditions without requiring separate models for each noise type

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

2Measurement precision

If neural network acoustic models use standard training methods, then training simplicity is maintained, but recognition accuracy in noisy environments deteriorates

Engineering Contradiction:
Improverecognition accuracy in noisy conditionsVSAvoidtraining complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The training process merges the main speech recognition task with side task prediction objectives into a unified training framework. The neural network is trained simultaneously on the primary acoustic model output and side task outputs (speech and interference predictions), combining multiple learning objectives into a single training process that improves noisy environment performance without requiring separate training procedures

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The training process incorporates feedback through loss functions that evaluate the difference between predicted outputs (main acoustic model and side task predictions) and target outputs. This feedback mechanism guides parameter updates to minimize errors in both speech recognition and interference separation, thereby improving accuracy in noisy conditions through iterative optimization

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS10147442B1Robust neural network acoustic model with side task prediction of reference signals
Publication Date: 2018.12.04 AMAZON TECH INC
  • US10147442B1 patent drawing
  • US10147442B1 patent drawing
  • US10147442B1 patent drawing

AI summary

A neural network acoustic model is trained to be robust and produce accurate output when used to process speech signals having acoustic interference. The neural network acoustic model can be trained using a source-separation process by which, in addition to producing the main acoustic model output for a given input, the neural network generates predictions of the separate speech and interference portions of the input. The parameters of the neural network can be adjusted to jointly optimize all three outputs (e.g., the main acoustic model output, the speech signal prediction, and the interference signal prediction), rather than only optimizing the main acoustic model output. Once trained, output layers for the speech and interference signal predictions can be removed from the neural network or otherwise disabled.