Mimicking the oracle: an initial phase decorrelation approach for class incremental learning

Conference item

Class Incremental Learning (CIL) aims at learning a classifier in a phase-by-phase manner, in which only data of a subset of the classes are provided at each phase. Previous works mainly focus on mitigating forgetting in phases after the initial one. However, we find that improving CIL at its initial phase is also a promising direction. Specifically, we experimentally show that directly encouraging CIL Learner at the initial phase to output similar representations as the model jointly trained on all classes can greatly boost the CIL performance. Motivated by this, we study the difference between a na¨ıvely-trained initial-phase model and the oracle model. Specifically, since one major difference between these two models is the number of training classes, we investigate how such difference affects the model representations. We find that, with fewer training classes, the data representations of each class lie in a long and narrow region; with more training classes, the representations of each class scatter more uniformly. Inspired by this observation, we propose Class-wise Decorrelation (CwD) that effectively regularizes representations of each class to scatter more uniformly, thus mimicking the model jointly trained with all classes (i.e., the oracle model). Our CwD is simple to implement and easy to plug into existing methods. Extensive experiments on various benchmark datasets show that CwD consistently and significantly improves the performance of existing state-of-the-art methods by around 1% to 3%.

Authors: Shi, Y; Zhou, K; Liang, J; Jiang, Z; Feng, J

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IEEE
• Host title: Proceedings of the 31st Conference on Computer Vision and Pattern Recognition (CVPR 2022)
• Pages: 16701-16710
• Publication date: 2022-09-27
• Acceptance date: 2022-06-19
• Event title: 31st Conference on Computer Vision and Pattern Recognition (CVPR 2022)
• Event location: New Orleans, LA, USA
• Event website: https://cvpr2022.thecvf.com/
• Event start date: 2022-06-19
• Event end date: 2022-06-24
• DOI: 10.1109/CVPR52688.2022.01622
• EISSN: 2575-7075
• ISSN: 1063-6919
• EISBN: 978-1-6654-6946-3
• ISBN: 978-1-6654-6947-0
• Language: English
• Keywords: FFR