Low-Rank Few-Shot Adaptation of Vision-Language Models
Maxime Zanella, Ismail Ben Ayed
TL;DR
This paper tackles the challenge of few-shot adaptation for Vision-Language Models by exploring Parameter-Efficient Fine-Tuning through Low-Rank Adaptation (LoRA). It introduces CLIP-LoRA, which applies low-rank updates to both vision and language encoders, using a fixed set of hyper-parameters across 11 datasets. Through extensive ablations, the authors show that LoRA-based fine-tuning can surpass state-of-the-art prompt- and adapter-based methods while reducing training time and memory overhead. The findings suggest that LoRA provides a strong, scalable baseline for fair comparison and progress in the rapidly evolving area of few-shot VLMs, and they offer guidance on where to place LoRA modules and how to choose ranks. Overall, this work highlights LoRA as a practical, competitive alternative for efficient cross-modal fine-tuning with minimal dataset-specific tuning.
Abstract
Recent progress in the few-shot adaptation of Vision-Language Models (VLMs) has further pushed their generalization capabilities, at the expense of just a few labeled samples within the target downstream task. However, this promising, already quite abundant few-shot literature has focused principally on prompt learning and, to a lesser extent, on adapters, overlooking the recent advances in Parameter-Efficient Fine-Tuning (PEFT). Furthermore, existing few-shot learning methods for VLMs often rely on heavy training procedures and/or carefully chosen, task-specific hyper-parameters, which might impede their applicability. In response, we introduce Low-Rank Adaptation (LoRA) in few-shot learning for VLMs, and show its potential on 11 datasets, in comparison to current state-of-the-art prompt- and adapter-based approaches. Surprisingly, our simple CLIP-LoRA method exhibits substantial improvements, while reducing the training times and keeping the same hyper-parameters in all the target tasks, i.e., across all the datasets and numbers of shots. Certainly, our surprising results do not dismiss the potential of prompt-learning and adapter-based research. However, we believe that our strong baseline could be used to evaluate progress in these emergent subjects in few-shot VLMs.
