CLIPArTT: Adaptation of CLIP to New Domains at Test Time

Gustavo A Vargas Hakim, David Osowiechi, Mehrdad Noori, Milad Cheraghalikhani, Ali Bahri, Moslem Yazdanpanah, Ismail Ben Ayed, Christian Desrosiers; Proceedings of the Winter Conference on Applications of Computer Vision (WACV), 2025, pp. 7092-7101

Pre-trained vision-language models (VLMs) exemplified by CLIP demonstrate remarkable adaptability across zero-shot classification tasks without additional training. However their performance diminishes in the presence of domain shifts. In this study we introduce CLIP Adaptation duRing Test-Time (CLIPArTT) a fully test-time adaptation (TTA) approach for CLIP which involves automatic text prompts construction during inference for their use as text supervision. Our method employs a unique minimally invasive text prompt tuning process wherein multiple predicted classes are aggregated into a single new text prompt used as pseudo label to re-classify inputs in a transductive manner. Additionally we pioneer the standardization of TTA benchmarks (e.g. TENT) in the realm of VLMs. Our findings demonstrate that without requiring additional transformations nor new trainable modules CLIPArTT enhances performance dynamically across non-corrupted datasets such as CIFAR-100 corrupted datasets like CIFAR-100-C and ImageNet-C alongside synthetic datasets such as VisDA-C. This research underscores the potential for improving VLMs' adaptability through novel test-time strategies offering insights for robust performance across varied datasets and environments. The code can be found at: https://github.com/dosowiechi/CLIPArTT.git