Supervised Fine-tuning in turn Improves Visual Foundation Models
Xiaohu Jiang, Yixiao Ge, Yuying Ge, Dachuan Shi, Chun Yuan, Ying Shan
TL;DR
This work proposes ViSFT, a two-stage supervised fine-tuning approach to enhance vision foundation models after image-text pretraining. By first training in-domain task heads with a frozen backbone and then updating the backbone with LoRA while keeping heads fixed, ViSFT transfers fine-grained knowledge into a lightweight parameter budget. Across OCR, GOI, zero-shot and few-shot classification, image-text retrieval, and VQA, ViSFT yields consistent out-of-domain gains on EVA-ViT backbones exceeding $4.4$B parameters, using a modest computational setup. The study demonstrates the value of targeted, stage-wise fine-tuning for unlocking hidden, fine-grained information in vision transformers to improve generalization without large-scale region-level data.
Abstract
Image-text training like CLIP has dominated the pretraining of vision foundation models in recent years. Subsequent efforts have been made to introduce region-level visual learning into CLIP's pretraining but face scalability challenges due to the lack of large-scale region-level datasets. Drawing inspiration from supervised fine-tuning (SFT) in natural language processing such as instruction tuning, we explore the potential of fine-grained SFT in enhancing the generation of vision foundation models after their pretraining. Thus a two-stage method ViSFT (Vision SFT) is proposed to unleash the fine-grained knowledge of vision foundation models. In ViSFT, the vision foundation model is enhanced by performing visual joint learning on some in-domain tasks and then tested on out-of-domain benchmarks. With updating using ViSFT on 8 V100 GPUs in less than 2 days, a vision transformer with over 4.4B parameters shows improvements across various out-of-domain benchmarks including vision and vision-linguistic scenarios.
