Title
The Hitchhiker's Guide to Prior-Shift Adaptation
Abstract
In many computer vision classification tasks, class priors at test time often differ from priors on the training set. In the case of such prior shift, classifiers must be adapted correspondingly to maintain close to optimal performance. This paper analyzes methods for adaptation of probabilistic classifiers to new priors and for estimating new priors on an unlabeled test set. We propose a novel method to address a known issue of prior estimation methods based on confusion matrices, where inconsistent estimates of decision probabilities and confusion matrices lead to negative values in the estimated priors. Experiments on fine-grained image classification datasets provide insight into the best practice of prior shift estimation and classifier adaptation, and show that the proposed method achieves state-of-the-art results in prior adaptation. Applying the best practice to two tasks with naturally imbalanced priors, learning from webcrawled images and plant species classification, increased the recognition accuracy by 1.1% and 3.4% respectively.
Year
DOI
Venue
2022
10.1109/WACV51458.2022.00209
2022 IEEE WINTER CONFERENCE ON APPLICATIONS OF COMPUTER VISION (WACV 2022)
DocType
ISSN
Citations 
Conference
2472-6737
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Tomas Sipka100.34
Milan Sulc200.68
Jiri Matas328314.03