核心概念
This paper proposes an open-set self-learning (OSSL) framework that dynamically adapts to changing data distributions, in contrast to existing methods that learn static and fixed decision boundaries.
要約
The paper addresses the limitations of existing open-set recognition (OSR) methods, which learn static and fixed decision boundaries using known class samples to reject unknown classes. This is insufficient for dynamic and open scenarios where unknown classes can emerge at any position in the feature space. Additionally, existing methods simply reject unknown class samples during testing without effectively utilizing them.
To address these issues, the paper proposes a "dynamic against dynamic" idea, where an open-set self-learning (OSSL) framework is developed. OSSL starts with a well-trained closed-set classifier and then self-trains with available test samples to adapt to changing data distributions.
The key components of OSSL are:
- A well-trained closed-set classifier as the starting point, which provides reliable pseudo-labeling of test data.
- A novel self-matching module that adaptively updates the classifier. It consists of:
- A classifier part that updates the model using known-label samples.
- An adversarial matching part that aligns the known-class distribution between labeled and unlabeled samples.
- A detection part that identifies unknown samples in the unlabeled set.
These components work collaboratively to enhance the model's discriminability and adapt it to the changing open-set world.
The paper also introduces two enhancement strategies:
- Injecting a small amount of ground-truth data from the training set to improve the reliability of model inference.
- Marginal logit loss for unknown classes to encourage uniformly distributed logits.
Extensive experiments on standard and cross-dataset benchmarks demonstrate that OSSL establishes new performance milestones, significantly outperforming existing OSR methods.
統計
The training set Dtr contains Ntr samples with known class labels from Ctr = {1, 2, ..., K} classes.
The test set Dte contains Nte samples with known class labels from Ctr and unknown class labels from Cte = {1, 2, ..., K, K+1}.
引用
"To face the challenge from the universal unknown classes in dynamic and open scenario, we propose the dynamic against dynamic idea and develop an open-set self-learning (OSSL) framework, which starts with a well-trained closed-set classifier as its starting point, and then self-trains with the available tested yet commonly deprecated samples for the model adaptation during testing."