Speech Endpoint Detection Using Silent Phonemes and WFST States

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Solution Overview

Problem

Current automatic speech recognition (ASR) systems face challenges in accurately determining the endpoint of speech due to imprecision in traditional pause detection methods, leading to incorrect cessation of speech processing, and require significant bandwidth and computing resources for remote processing, raising privacy concerns and inefficiencies.

Innovation Solution

A hybrid approach using a WFST accelerator with hardware and software components on a local device for decoding speech, incorporating a WFST language model and a personalized grammar model to improve accuracy and reduce remote processing needs, along with an endpointing module to accurately detect speech endpoints by counting silent frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional pause detection methods are used to determine speech endpoint, then the system is simple to implement, but the endpoint detection precision deteriorates leading to incorrect cessation of speech processing

Engineering Contradiction:
Improveendpoint detection precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The speech processing system is segmented into local and remote components. The local device performs preliminary speech decoding and endpoint detection using a WFST accelerator and silent frame counting, while the remote server handles final recognition. This segmentation allows precise endpoint detection locally without requiring complex remote processing for every frame.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary speech decoding and endpoint detection locally before transmitting to the remote server. By counting silent frames and identifying speech endpoints in advance, the system prepares data locally, reducing the need for complex continuous remote monitoring and enabling more precise endpoint detection.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If remote processing is used for speech recognition, then the system can leverage powerful computing resources, but bandwidth consumption and computing resource usage increase

Engineering Contradiction:
Improvespeech recognition accuracyVSAvoidbandwidth and computing resource usage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system extracts and processes only the essential speech data locally using a WFST accelerator for decoding and silent frame counting for endpoint detection. By taking out and handling the preliminary processing locally, the system reduces the amount of data that needs to be transmitted and processed remotely, thereby reducing bandwidth consumption and remote computing resource usage while maintaining recognition accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The local device performs self-service speech decoding using the WFST accelerator and conducts its own endpoint detection by counting silent frames. This self-service capability reduces dependency on remote processing for every speech frame, thereby reducing bandwidth consumption and remote computing resource usage while maintaining speech recognition accuracy through local preprocessing.

Inventive Principle:
Principle #25Self-service

3Reliability

If all speech data is transmitted to remote server for processing, then the system can achieve high recognition accuracy, but privacy concerns increase and processing efficiency decreases

Engineering Contradiction:
Improvespeech recognition accuracyVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The speech processing workflow is segmented into local decoding and endpoint detection, followed by selective remote recognition. By dividing the processing tasks, the system maintains high recognition accuracy through remote server capabilities while improving processing efficiency by handling routine tasks locally and reducing data transmission requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary speech decoding and endpoint detection locally before transmitting to the remote server. This preliminary action reduces the amount of data requiring remote processing, thereby improving processing efficiency while maintaining recognition accuracy through the combined local-remote approach.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11727917B1Silent phonemes for tracking end of speech
Publication Date: 2023.08.15 AMAZON TECH INC
  • US11727917B1 patent drawing
  • US11727917B1 patent drawing
  • US11727917B1 patent drawing

AI summary

Embodiments describe a method for speech endpoint detection including receiving identification data for a first state associated with a first frame of speech data from a WFST language model, determining that the first frame of the speech data includes silence data, incrementing a silence counter associated with the first state, copying a value of the silence counter of the first state to a corresponding silence counter field in a second state associated with the first state in an active state list, and determining that the value of the silence counter for the first state is above a silence threshold. The method further includes, determining that an endpoint of the speech has occurred in response to determining that the silence counter is above the silence threshold, and outputting text data representing a plurality of words determined from the speech data that was received prior to the endpoint.