Test-time adaptation via self-training with future information

Test-time adaptation (TTA) aims to address potential differences in data distribution between the training and testing phases by modifying a pretrained model based on each specific test sample. This process is especially crucial for deep learning models, as they often encounter frequent changes in the testing environment. Currently, popular TTA methods rely primarily on pseudo-labels (PLs) as supervision signals and fine-tune the model through backpropagation. Consequently, the success of the model's adaptation depends directly on the quality of the PLs. High-quality PLs can enhance the model's performance, whereas low-quality ones may lead to poor adaptation results. Intuitively, if the PLs predicted by the model for a given sample remain consistent in both the current and future states, it suggests a higher confidence in that prediction. Using such consistent PLs as supervision signals can greatly benefit long-term adaptation. Nevertheless, this approach may induce overconfidence in the model's predictions. To counter this, we introduce a regularization term that penalizes overly confident predictions. Our proposed method is highly versatile and can be seamlessly integrated with various TTA strategies, making it immensely practical. We investigate different TTA methods on three widely used datasets (CIFAR10C, CIFAR100C, and ImageNetC) with different scenarios and show that our method achieves competitive or state-of-the-art accuracies on all of them.