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Margin Calibration for Long-Tailed Visual Recognition
Proceedings of The 14th Asian Conference on Machine
Learning, PMLR 189:1101-1116, 2023.
Abstract
Long-tailed visual recognition tasks pose great
challenges for neural networks on how to handle the
imbalanced predictions between head (common) and
tail (rare) classes, i.e., models tend to classify
tail classes as head classes. While existing
research focused on data resampling and loss
function engineering, in this paper, we take a
different perspective: the classification
margins. We study the relationship between the
margins and logits and empirically observe that the
uncalibrated margins and logits are positively
correlated. We propose a simple yet effective MARgin
Calibration approach (MARC) to calibrate the margins
to obtain better logits. We validate MARC through
extensive experiments on common long-tailed
benchmarks including CIFAR-LT, ImageNet-LT,
Places-LT, and iNaturalist-LT. Experimental results
demonstrate that our MARC achieves favorable results
on these benchmarks. In addition, MARC is extremely
easy to implement with just three lines of code. We
hope this simple approach will motivate people to
rethink the uncalibrated margins and logits in
long-tailed visual recognition.