Meta OOD Learning for Continuously Adaptive OOD Detection
Xinheng Wu Jie Lu Zhen Fang Guangquan Zhang
Out-of-distribution (OOD) detection is crucial to modern deep learning
applications by identifying and alerting about the OOD samples that should not
be tested or used for making predictions. Current OOD detection methods have
made significant progress when in-distribution (ID) and OOD samples are drawn
from static distributions. However, this can be unrealistic when applied to
real-world systems which often undergo continuous variations and shifts in ID
and OOD distributions over time. Therefore, for an effective application in
real-world systems, the development of OOD detection methods that can adapt to
these dynamic and evolving distributions is essential. In this paper, we
propose a novel and more realistic setting called continuously adaptive
out-of-distribution (CAOOD) detection which targets on developing an OOD
detection model that enables dynamic and quick adaptation to a new arriving
distribution, with insufficient ID samples during deployment time. To address
CAOOD, we develop meta OOD learning (MOL) by designing a learning-to-adapt
diagram such that a good initialized OOD detection model is learned during the
training process. In the testing process, MOL ensures OOD detection performance
over shifting distributions by quickly adapting to new distributions with a few
adaptations. Extensive experiments on several OOD benchmarks endorse the
effectiveness of our method in preserving both ID classification accuracy and
OOD detection performance on continuously shifting distributions.