EquiME: Equitable Micro-Expression Dataset for Cross-Demographic Emotion Recognition

Instances of the generated micro-expressions by EquiME. The prompt is designed based on the respective facial action units (FACS) for each type of emotion.

Intro Image
Introductory Illustration of EquiME
EquiME Model Architecture
Pipeline for Synthetic ME Dataset Generation

Abstract

Micro-expression (ME) recognition is a challenging task due to the subtle and transient nature of these facial movements. Existing real-world ME datasets are limited in scale, diversity, and emotional breadth, hindering the development of robust recognition models. In this work, we introduce EquiME, a large-scale synthetic dataset for micro-expression analysis, generated using the image-to-video model. By leveraging a structured causal modeling approach, we employ Facial Action Units (AUs) as intermediate representations that drive the generation of realistic ME sequences. Our dataset achieves significant demographic diversity (55.6% women, 44.4% men; representation across six racial groups) while simultaneously capturing five distinct emotion categories—a balance rarely achieved in real-world data collection where recruiting diverse participants capable of expressing all target emotions remains challenging. Experimental results show that training on EquiME, followed by cross-validation evaluation, it shows consistency of performance across different model architectures. This paper presents a streamlined pipeline for generating synthetic micro-expression datasets, designed to be accessible to users without a computer science background.

Dataset Comparison

Comparison between existing real human ME datasets, MiE-X (synthetic dataset), and EquiME (ours)
Characteristics Real Human ME Datasets MiE-X Dataset EquiME (Ours)
Data Format Video Sequences
(Spontaneous or Elicited)
Static Images
(Apex & Onset frames)
Video Sequences
(Temporal Data)
Dataset Scale
Subjects 20-40 5,000 15,000
Samples 100-300 45,000 75,000 (15,000 × 5 class)
Emotion Classes 3-7 Classes
(Often imbalanced)
3 Classes 5 Classes
• Happiness
• Sadness
• Surprise
• Disgust
• Anger
• Fear
• Contempt (some datasets)
• Positive
• Negative
• Surprise
• Happiness
• Sadness
• Surprise
• Disgust
• Anger
Technical Specifications
Resolution Varies (often 640×480 or higher) 128 x 128 pixels 256 × 256 pixels
Customization No No Yes
Data Collection Lab environment
(Controlled conditions)
Synthetic Synthetic
Note: EquiME offers comprehensive temporal information similar to real datasets but with much larger scale and balanced emotion distribution

3-Class Classification Results

Performance comparison on EquiME dataset (3-class)
Model Accuracy F1-Score Mean Confidence
ST-CNN 0.630 0.49 0.6031
ResNet3D 0.481 0.61 0.597
Simple3DCNN 0.489 0.63 0.679
MobileNet-Hybrid 0.538 0.63 0.627

5-Class Classification Results

Performance comparison on EquiME dataset (5-class)
Model Accuracy F1-Score Mean Confidence
ResNet3D 0.420 0.36 0.563
MobileNet-Hybrid 0.470 0.45 0.3591

BibTeX


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