ASR Model Combining WFST and Attention Decoder for IVR

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Solution Overview

Problem

Conventional automatic speech recognition (ASR) systems struggle with high accuracy when processing short utterances, such as names or commands, in interactive voice response (IVR) systems, leading to user frustration.

Innovation Solution

An ASR model that combines a trained weighted finite state transducer (WFST) with an attention decoder to efficiently identify candidate names or commands, using a WFST to configure the system to listen for a wide range of commands and an attention decoder to select the best result with high accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional ASR systems are used to process short utterances in IVR systems, then the system structure remains simple, but the recognition accuracy deteriorates

Engineering Contradiction:
Improverecognition accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The ASR system is segmented into distinct functional modules: acoustic model for phoneme recognition, language model for contextual understanding, and decision model for final transcription. This segmentation allows each module to specialize in specific aspects of speech recognition, improving overall accuracy for short utterances while maintaining manageable system complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from traditional single-dimension speech-to-text processing to a multi-dimensional approach by integrating acoustic, linguistic, and decision-making dimensions. This dimensional expansion enables the system to capture both phonetic information and contextual meaning, significantly improving recognition accuracy for brief speech inputs

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If generic ASR software is used for IVR commands, then the system is easy to implement, but the understanding of short commands deteriorates

Engineering Contradiction:
Improvecommand understandingVSAvoidimplementation ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The ASR system implements local quality by optimizing specific components for IVR command recognition rather than using uniform generic processing. The language model is tailored with domain-specific vocabulary and grammar patterns relevant to IVR systems, while the acoustic model is fine-tuned for the particular speech characteristics of command utterances, thereby improving reliability without requiring complete system redesign

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system performs preliminary action by pre-training and fine-tuning models with IVR-specific data before deployment. The acoustic and language models are预先 configured with knowledge of typical IVR command structures, enabling them to reliably understand short commands from the outset rather than requiring extensive adaptation during operation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20250046300A1Automatic speech recognition for interactive voice response systems
Publication Date: 2025.02.06 ZOOM VIDEO COMM INC
  • US20250046300A1 patent drawing
  • US20250046300A1 patent drawing
  • US20250046300A1 patent drawing

AI summary

One example method includes receiving an audio input from a user; determining, using a first trained model, a plurality of candidate commands; determining, using a second trained model, a recognized command from the plurality of candidate commands; and identifying a corresponding valid command in a set of valid commands based on the recognized command.