Domain-Specific Block Selection and Paired-View Pseudo-Labeling for Online Test-Time Adaptation

Test-time adaptation (TTA) aims to adapt a pre-trained model to a new test domain without access to source data after deployment. Existing approaches typically rely on self-training with pseudo-labels since ground-truth cannot be obtained from test data. Although the quality of pseudo labels is important for stable and accurate long-term adaptation it has not been previously addressed. In this work we propose DPLOT a simple yet effective TTA framework that consists of two components: (1) domain-specific block selection and (2) pseudo-label generation using paired-view images. Specifically we select blocks that involve domain-specific feature extraction and train these blocks by entropy minimization. After blocks are adjusted for current test domain we generate pseudo-labels by averaging given test images and corresponding flipped counterparts. By simply using flip augmentation we prevent a decrease in the quality of the pseudo-labels which can be caused by the domain gap resulting from strong augmentation. Our experimental results demonstrate that DPLOT outperforms previous TTA methods in CIFAR10-C CIFAR100-C and ImageNet-C benchmarks reducing error by up to 5.4% 9.1% and 2.9% respectively. Also we provide an extensive analysis to demonstrate effectiveness of our framework. Code is available at https://github.com/gist-ailab/domain-specific-block-selection-and-paired-view-pseudo-labeling-for-online-TTA.