Bowen Wang, Liangzhi Li, Manisha Verma, Yuta Nakashima, Ryo Kawasaki, Hajime Nagahara
Few-shot learning (FSL) approaches are usually based on an assumption that the pre-trained knowledge can be obtained from base (seen) categories and can be well transferred to novel (unseen) categories. However, there is no guarantee, especially for the latter part. This issue leads to the unknown nature of the inference process in most FSL methods, which hampers its application in some risk-sensitive areas. In this paper, we reveal a new way to perform FSL for image classification, using visual representations from the backbone model and weights generated by a newly-emerged explainable classifier. The weighted representations only include a minimum number of distinguishable features and the visualized weights can serve as an informative hint for the FSL process. Finally, a discriminator will compare the representations of each pair of the images in the support set and the query set. Pairs with the highest scores will decide the classification results. Experimental results prove that the proposed method can achieve both good accuracy and satisfactory explainability on three mainstream datasets.
| Task | Dataset | Metric | Value | Model |
|---|---|---|---|---|
| Image Classification | CIFAR-FS 5-way (1-shot) | Accuracy | 68.34 | MTUNet+WRN |
| Image Classification | CIFAR-FS 5-way (1-shot) | Accuracy | 66.31 | MTUNet+ResNet-18 |
| Image Classification | Mini-Imagenet 5-way (5-shot) | Accuracy | 71.93 | MTUNet+WRN |
| Image Classification | Mini-Imagenet 5-way (5-shot) | Accuracy | 70.22 | MTUNet+ResNet-18 |
| Image Classification | Mini-Imagenet 5-way (1-shot) | Accuracy | 56.12 | MTUNet+WRN |
| Image Classification | Mini-Imagenet 5-way (1-shot) | Accuracy | 55.03 | MTUNet+ResNet-18 |
| Image Classification | Tiered ImageNet 5-way (1-shot) | Accuracy | 62.42 | MTUNet+WRN |
| Image Classification | Tiered ImageNet 5-way (1-shot) | Accuracy | 61.27 | MTUNet+ResNet-18 |
| Image Classification | Tiered ImageNet 5-way (5-shot) | Accuracy | 80.05 | MTUNet+WRN |
| Image Classification | Tiered ImageNet 5-way (5-shot) | Accuracy | 77.82 | MTUNet+ResNet-18 |
| Image Classification | CIFAR-FS 5-way (5-shot) | Accuracy | 82.93 | MTUNet+WRN |
| Image Classification | CIFAR-FS 5-way (5-shot) | Accuracy | 80.16 | MTUNet+ResNet-18 |
| Few-Shot Image Classification | CIFAR-FS 5-way (1-shot) | Accuracy | 68.34 | MTUNet+WRN |
| Few-Shot Image Classification | CIFAR-FS 5-way (1-shot) | Accuracy | 66.31 | MTUNet+ResNet-18 |
| Few-Shot Image Classification | Mini-Imagenet 5-way (5-shot) | Accuracy | 71.93 | MTUNet+WRN |
| Few-Shot Image Classification | Mini-Imagenet 5-way (5-shot) | Accuracy | 70.22 | MTUNet+ResNet-18 |
| Few-Shot Image Classification | Mini-Imagenet 5-way (1-shot) | Accuracy | 56.12 | MTUNet+WRN |
| Few-Shot Image Classification | Mini-Imagenet 5-way (1-shot) | Accuracy | 55.03 | MTUNet+ResNet-18 |
| Few-Shot Image Classification | Tiered ImageNet 5-way (1-shot) | Accuracy | 62.42 | MTUNet+WRN |
| Few-Shot Image Classification | Tiered ImageNet 5-way (1-shot) | Accuracy | 61.27 | MTUNet+ResNet-18 |
| Few-Shot Image Classification | Tiered ImageNet 5-way (5-shot) | Accuracy | 80.05 | MTUNet+WRN |
| Few-Shot Image Classification | Tiered ImageNet 5-way (5-shot) | Accuracy | 77.82 | MTUNet+ResNet-18 |
| Few-Shot Image Classification | CIFAR-FS 5-way (5-shot) | Accuracy | 82.93 | MTUNet+WRN |
| Few-Shot Image Classification | CIFAR-FS 5-way (5-shot) | Accuracy | 80.16 | MTUNet+ResNet-18 |