FeCAM: Exploiting the Heterogeneity of Class Distributions in Exemplar-Free Continual Learning

Fuente: arXiv
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Hauptverfasser: Goswami, Dipam, Liu, Yuyang, Twardowski, Bartłomiej, van de Weijer, Joost
Format: Preprint
Veröffentlicht: 2023
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author Goswami, Dipam
Liu, Yuyang
Twardowski, Bartłomiej
van de Weijer, Joost
author_facet Goswami, Dipam
Liu, Yuyang
Twardowski, Bartłomiej
van de Weijer, Joost
contents Exemplar-free class-incremental learning (CIL) poses several challenges since it prohibits the rehearsal of data from previous tasks and thus suffers from catastrophic forgetting. Recent approaches to incrementally learning the classifier by freezing the feature extractor after the first task have gained much attention. In this paper, we explore prototypical networks for CIL, which generate new class prototypes using the frozen feature extractor and classify the features based on the Euclidean distance to the prototypes. In an analysis of the feature distributions of classes, we show that classification based on Euclidean metrics is successful for jointly trained features. However, when learning from non-stationary data, we observe that the Euclidean metric is suboptimal and that feature distributions are heterogeneous. To address this challenge, we revisit the anisotropic Mahalanobis distance for CIL. In addition, we empirically show that modeling the feature covariance relations is better than previous attempts at sampling features from normal distributions and training a linear classifier. Unlike existing methods, our approach generalizes to both many- and few-shot CIL settings, as well as to domain-incremental settings. Interestingly, without updating the backbone network, our method obtains state-of-the-art results on several standard continual learning benchmarks. Code is available at https://github.com/dipamgoswami/FeCAM.
format Preprint
id arxiv_https___arxiv_org_abs_2309_14062
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle FeCAM: Exploiting the Heterogeneity of Class Distributions in Exemplar-Free Continual Learning
Goswami, Dipam
Liu, Yuyang
Twardowski, Bartłomiej
van de Weijer, Joost
Computer Vision and Pattern Recognition
Machine Learning
Exemplar-free class-incremental learning (CIL) poses several challenges since it prohibits the rehearsal of data from previous tasks and thus suffers from catastrophic forgetting. Recent approaches to incrementally learning the classifier by freezing the feature extractor after the first task have gained much attention. In this paper, we explore prototypical networks for CIL, which generate new class prototypes using the frozen feature extractor and classify the features based on the Euclidean distance to the prototypes. In an analysis of the feature distributions of classes, we show that classification based on Euclidean metrics is successful for jointly trained features. However, when learning from non-stationary data, we observe that the Euclidean metric is suboptimal and that feature distributions are heterogeneous. To address this challenge, we revisit the anisotropic Mahalanobis distance for CIL. In addition, we empirically show that modeling the feature covariance relations is better than previous attempts at sampling features from normal distributions and training a linear classifier. Unlike existing methods, our approach generalizes to both many- and few-shot CIL settings, as well as to domain-incremental settings. Interestingly, without updating the backbone network, our method obtains state-of-the-art results on several standard continual learning benchmarks. Code is available at https://github.com/dipamgoswami/FeCAM.
title FeCAM: Exploiting the Heterogeneity of Class Distributions in Exemplar-Free Continual Learning
topic Computer Vision and Pattern Recognition
Machine Learning
url https://arxiv.org/abs/2309.14062