Continual Learning with Pretrained Backbones by Tuning in the Input Space
This addresses the problem of adapting deep learning models to non-stationary environments for real-world supervised learning tasks, but it is incremental as it builds on existing fine-tuning and continual learning methods.
The paper tackles catastrophic forgetting in continual learning by fine-tuning only the classification head and input transformation parameters, preserving pre-trained backbone knowledge. Experiments on four image classification tasks show the approach achieves a good trade-off between plasticity and stability with modest computational effort.
The intrinsic difficulty in adapting deep learning models to non-stationary environments limits the applicability of neural networks to real-world tasks. This issue is critical in practical supervised learning settings, such as the ones in which a pre-trained model computes projections toward a latent space where different task predictors are sequentially learned over time. As a matter of fact, incrementally fine-tuning the whole model to better adapt to new tasks usually results in catastrophic forgetting, with decreasing performance over the past experiences and losing valuable knowledge from the pre-training stage. In this paper, we propose a novel strategy to make the fine-tuning procedure more effective, by avoiding to update the pre-trained part of the network and learning not only the usual classification head, but also a set of newly-introduced learnable parameters that are responsible for transforming the input data. This process allows the network to effectively leverage the pre-training knowledge and find a good trade-off between plasticity and stability with modest computational efforts, thus especially suitable for on-the-edge settings. Our experiments on four image classification problems in a continual learning setting confirm the quality of the proposed approach when compared to several fine-tuning procedures and to popular continual learning methods.