Differential Speech Emotion Recognition for User-Aligned Accuracy

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Solution Overview

Problem

Existing emotion recognition systems rely on subjective rules or parameters set by developers or labelers, leading to inaccuracies in emotion recognition due to speaker and environmental characteristics, and fail to accurately reflect actual user impressions.

Innovation Solution

An emotion recognition system that infers differential emotions between two pieces of speech data from the same speaker, using a differential-emotion recognition model to quantify relative emotions, reducing the influence of speaker and environmental variables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rule-based method or machine learning method is used to recognize emotions from single speech data, then emotion recognition can be performed, but the recognition accuracy deviates from actual user impression due to subjectivity of developers or labelers

Engineering Contradiction:
Improveemotion recognition accuracyVSAvoidalignment with user impression
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

Instead of recognizing absolute emotions from single speech data (conventional approach), the patent inverts the approach by recognizing differential emotions between two speech data pieces. The differential-emotion recognition model calculates the difference between emotions in first speech data and second speech data, thereby eliminating subjective biases from absolute emotion labeling by developers or labelers and achieving results that better align with actual user impressions.

Inventive Principle:
Principle #13The other way round (Inversion)

2Productivity

If absolute emotion recognition is performed from single speech data, then emotion categories can be output, but speaker and environmental characteristics cause inaccuracies

Engineering Contradiction:
Improveemotion recognition outputVSAvoidemotion recognition accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent extracts and eliminates the harmful factors (speaker characteristics and environmental characteristics) by computing the differential emotion between two speech data pieces from the same speaker. By taking the difference, these confounding factors cancel out, leaving only the genuine emotion changes, thereby improving recognition accuracy while maintaining productivity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If differential emotion recognition between two speech data pieces is performed, then accuracy aligning with user impression is achieved, but system complexity increases

Engineering Contradiction:
Improveemotion recognition accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter being recognized from absolute emotion values to differential emotion values. By transforming the recognition task from estimating absolute emotion states to calculating emotion differences between two time points, the system achieves higher accuracy aligned with user impressions. The differential-emotion recognition model processes pairs of speech data and outputs emotion transitions, managing complexity through focused differential analysis rather than absolute state estimation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12499905B2Emotion recognition system and emotion recognition method
Publication Date: 2025.12.16 HITACHI LTD
  • US12499905B2 patent drawing
  • US12499905B2 patent drawing
  • US12499905B2 patent drawing

AI summary

An emotion recognition system includes an input unit configured to input first speech data and second speech data, and a processing unit configured to input the first speech data and the second speech data to a differential-emotion recognition model that infers a differential emotion between two pieces of speech data, and acquire, from the differential-emotion recognition model, differential-emotion information indicating a differential emotion between the first speech data and the second speech data.