Speech Recognition Field Identification via Frequency-Based Language Model

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Solution Overview

Problem

Existing speech recognition technologies face challenges in accurately identifying the field of input speech when it is unknown, leading to increased processing loads due to the need for multiple language models and manual classification of speech files.

Innovation Solution

A speech recognition apparatus and method that generates an identification language model by selecting phrases with high appearance frequency on a field-by-field basis, allowing for automatic field determination and reduced processing load by using a single identification language model for initial recognition, followed by customization of the language model for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple language models are prepared to handle unknown field speech, then the ability to recognize speech from unknown fields is improved, but the processing load increases excessively

Engineering Contradiction:
Improveability to recognize speech from unknown fieldsVSAvoidprocessing load
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the language model selection process into two stages: first using a general-purpose language model for initial recognition, then selectively switching to field-specific language models only when needed. This segmentation allows the system to handle unknown field speech without continuously operating multiple specialized models, thus reducing processing load while maintaining adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic language model selection based on field identification results. The system transitions from a static configuration of multiple fixed language models to a dynamic approach where the appropriate language model is selected and switched based on real-time field detection, optimizing processing resources according to actual speech content.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If multiple language models are used to improve recognition accuracy for specific fields, then recognition accuracy for known fields is improved, but the complexity of the system increases

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

Solution Approach 1:

The patent employs a universal general-purpose language model that can handle all fields as its primary function, while field-specific language models serve as supplementary specialized functions. This multi-functionality approach allows the system to maintain high recognition accuracy for known fields through specialization while avoiding the complexity of requiring separate dedicated models for every possible field.

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

Solution Approach 2:

The patent performs preliminary field identification using a general-purpose language model before engaging field-specific language models. This preliminary action filters out the need for multiple specialized models in most cases, reducing system complexity while preserving the ability to achieve high accuracy when field-specific recognition is required.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If manual classification of speech files by field is performed in advance, then the organization of speech data is improved, but the time and labor required increase

Engineering Contradiction:
Improveorganization of speech dataVSAvoidtime and labor for classification
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent implements automatic field identification where the speech recognition system itself performs the classification function by detecting the field from the speech content in real-time. This self-service approach eliminates the need for manual pre-classification of speech files, significantly reducing time and labor requirements while maintaining effective organization of speech data by field.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS9142211B2Speech recognition apparatus, speech recognition method, and computer-readable recording medium
Publication Date: 2015.09.22 NEC CORP
  • US9142211B2 patent drawing
  • US9142211B2 patent drawing
  • US9142211B2 patent drawing

AI summary

A speech recognition apparatus 20 includes: an identification language model creation unit 21 that selects, from learning texts 27 for various fields for generating language models 26 for the fields, a phrase that includes a word whose appearance frequency satisfies a set condition on a field-by-field basis, and generates an identification language model 25 for identifying the field of speech using the selected phrases; a speech recognition unit 22 that executes speech recognition on the speech using the identification language model 25, and outputs text data and word confidences as a recognition result; and a field determination unit 23 that specifies a field that includes the most words whose confidences are greater than or equal to a set value based on the text data, the word confidences, and the words in the learning texts for the fields, and determines that the specified field is the field of the speech.