2023

Towards Stable Test-Time Adaptation in Dynamic Wild World

Niu, Shuaicheng, Wu, Jiaxiang, Zhang, Yifan et al.

Understand

Test-time adaptation (TTA) has shown to be effective at tackling distribution shifts between training and testing data by adapting a given model on test samples.

  • However, the online model updating of TTA may be unstable and this is often a key obstacle preventing existing TTA methods from being deployed in the real world.
  • Specifically, TTA may fail to improve or even harm the model performance when test data have: 1) mixed distribution shifts, 2) small batch sizes, and 3) online imbalanced label distribution shifts, which are quite common in practice.
  • In this paper, we investigate the unstable reasons and find that the batch norm layer is a crucial factor hindering TTA stability.

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