Controllable Forgetting Mechanism for Few-Shot Class-Incremental Learning

TL;DR

This paper presents a controllable forgetting mechanism for few-shot class-incremental learning that balances adapting to new classes with retaining previous knowledge, especially effective in ultra-low-shot scenarios.

Contribution

It introduces a Novel Class Detection rule and new metrics to control and quantify the trade-off between novel and base class performance in FSCIL.

Findings

Up to 30% improvement in novel class accuracy on CIFAR100.

Maintains a low base class forgetting rate of 2%.

Effective in ultra-low-shot (1-shot) scenarios.

Abstract

Class-incremental learning in the context of limited personal labeled samples (few-shot) is critical for numerous real-world applications, such as smart home devices. A key challenge in these scenarios is balancing the trade-off between adapting to new, personalized classes and maintaining the performance of the model on the original, base classes. Fine-tuning the model on novel classes often leads to the phenomenon of catastrophic forgetting, where the accuracy of base classes declines unpredictably and significantly. In this paper, we propose a simple yet effective mechanism to address this challenge by controlling the trade-off between novel and base class accuracy. We specifically target the ultra-low-shot scenario, where only a single example is available per novel class. Our approach introduces a Novel Class Detection (NCD) rule, which adjusts the degree of forgetting a priori while simultaneously enhancing performance on novel classes. We demonstrate the versatility of our solution by applying it to state-of-the-art Few-Shot Class-Incremental Learning (FSCIL) methods, showing consistent improvements across different settings. To better quantify the trade-off between novel and base class performance, we introduce new metrics: NCR@2FOR and NCR@5FOR. Our approach achieves up to a 30% improvement in novel class accuracy on the CIFAR100 dataset (1-shot, 1 novel class) while maintaining a controlled base class forgetting rate of 2%.