Leveraging Model Soups to Classify Intangible Cultural Heritage Images from the Mekong Delta
Organizations: College of Information and Communication Technology, Can Tho University · School of Graduate, Can Tho University
Abstract
The classification of Intangible Cultural Heritage (ICH) images in the Mekong Delta poses unique challenges due to limited annotated data, high visual similarity among classes, and domain heterogeneity. In such low-resource settings, conventional deep learning models often suffer from high variance or overfit to spurious correlations, leading to poor generalization. To address these limitations, we propose a robust framework that integrates the hybrid CoAtNet architecture with model soups, a lightweight weight-space ensembling technique that averages checkpoints from a single training trajectory without increasing inference cost. CoAtNet captures both local and global patterns through stage-wise fusion of convolution and self-attention. We apply two ensembling strategies - greedy and uniform soup - to selectively combine diverse checkpoints into a final model. Beyond performance improvements, we analyze the ensembling effect through the lens of bias-variance decomposition. Our findings show that model soups reduces variance by stabilizing predictions across diverse model snapshots, while introducing minimal additional bias. Furthermore, using cross-entropy-based distance metrics and Multidimensional Scaling (MDS), we show that model soups selects geometrically diverse checkpoints, unlike Soft Voting, which blends redundant models centered in output space. Evaluated on the ICH-17 dataset (7,406 images across 17 classes), our approach achieves state-of-the-art results with 72.36% top-1 accuracy and 69.28% macro F1-score, outperforming strong baselines including ResNet-50, DenseNet-121, and ViT. These results underscore that diversity-aware checkpoint averaging provides a principled and efficient way to reduce variance and enhance generalization in culturally rich, data-scarce classification tasks.
Figures & tables
| No. | Category | # Images |
| 1 | Đờn ca Tài tử Nam Bộ Art of Don ca Tai tu music and song in southern Viet Nam | 513 |
| 2 | Nghệ thuật Chầm riêng chà pây của người Khmer Khmer Cham rieng cha pay art | 185 |
| 3 | Nghề dệt chiếu Mat weaving | 642 |
| 4 | Lễ hội cúng biển Mỹ Long My Long Sea worship festival | 398 |
| 5 | Nghệ thuật sân khấu Dù Kê của người Khmer Du Ke (or Lakhon Bassac) Theater Arts of the Khmer people | 404 |
| 6 | Lễ hội Ok Om Bok của người Khmer Khmer Ok Om Bok festival | 465 |
| Class | Train | Validation | Test | Total |
| 1 | 420 | 41 | 52 | 513 |
| 2 | 151 | 15 | 19 | 185 |
| 3 | 525 | 52 | 65 | 642 |
| 4 | 326 | 32 | 40 | 398 |
| 5 | 330 | 33 | 41 | 404 |
| 6 | 380 | 38 | 47 | 465 |
| Model | # Params (M) |
| ResNet-50 | 23.54 |
| DenseNet-121 | 6.97 |
| ViT | 85.81 |
| CoAtNet-0 | 26.68 |
| CoAtNet-2 | 72.86 |
| Model | Accuracy | Precision | Recall | F1 |
| ResNet-50 | 65.55 | 64.72 | 62.33 | 62.80 |
| DenseNet-121 | 64.35 | 60.33 | 60.33 | 60.02 |
| ViT | 70.09 | 68.79 | 66.99 | 67.41 |
| Do et al. [ 5 ] | 65.32 ∗ | – | – | – |
| Tran et al. [ 12 ] | 66.76 ∗ | – | – | – |
| CoAtNet-0 | 70.63 | 67.66 | 66.17 | 65.98 |
| Class | Accuracy | Precision | Recall | F1 | ||||
| best | soups | best | soups | best | soups | best | soups | |
| 1 | 88.46 | 88.46 | 80.70 | 85.19 | 88.46 | 88.46 | 84.40 | 86.79 |
| 2 | 47.37 | 47.37 | 75.00 | 69.23 | 47.37 | 47.37 | 58.06 | 56.25 |
| 3 | 93.85 | 92.31 | 95.31 | 95.24 | 93.85 | 92.31 | 94.57 | 93.75 |
| 4 | 22.50 | 25.00 | 28.12 | 33.33 | 22.50 | 25.00 | 25.00 | 28.57 |
| 5 | 65.85 | 65.85 | 64.29 | 71.05 | 65.85 | 65.85 | 65.06 | 68.35 |
| Aspect | Soft Voting | Model Soups |
| Inference Cost | High (all models active) | Low (single averaged model) |
| Memory Footprint | Scales with number of models | Constant (single model) |
| Deployment Simplicity | Requires parallel model storage | Simple (one model checkpoint) |
| Bias Reduction | Limited | Slight increase (depends on soup strategy) |
| Variance Reduction | Moderate (correlated models) | High (diverse checkpoint averaging) |
| Model | Accuracy | Precision | Recall | F1 |
| CoAtNet-0 | 49.13 | 46.36 | 45.31 | 44.85 |
| CoAtNet-2 | 51.27 | 48.87 | 48.21 | 47.81 |
| CoAtNet-2 + uniform | ||||
| CoAtNet-2 + greedy |
Image Classification
Image classification assigns semantic labels to images, enabling recognition of objects, scenes, conditions, and fine-grained categories.
See all 386 papers