Tricking Open-World Object Recognition Models: Uncertainty in Out-of-Distribution Detection

Wout Teillers, Matias Valdenegro-Toro


Abstract
Object recognition models are well studied on benchmark datasets, typically focusing on performance in retrieving objects that exist in images. However, in real-life scenarios there is no prior knowledge of an object’s existence, and current research fails to assess model performance in these situations. This research aims to shed light on this problem by testing three Open-World models, YOLO-World, Grounding Dino and GPT-4o, on the LVIS, Open Images, and JUS datasets. We design an experiment where models are confronted with impossible prompts by instructing them to retrieve non-existing objects. This allows us to observe the models’ uncertainty performance. Overall, GPT-4o performed poorest with regard to object recognition and uncertainty estimation. GPT-4o showed to be highly overconfident. In contrast, YOLO-World and Grounding Dino are slightly underconfident, but they are superior in their uncertainty calibration in comparison to GPT-4o. However, all three models occasionally assign high confident predictions to non-existing objects. Showing that improvement can still be made to the uncertainty estimation of these models when confronted with impossible prompts.
Anthology ID:
2026.knowfm-1.12
Volume:
Proceedings of the 4th Workshop on Towards Knowledgeable Foundation Models (KnowFM 2026)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Canyu Chen, Yuji Zhang, Zoey Sha Li, Zihan Wang, Qineng Wang, Jinyan Su, Priyanka Kargupta, Sara Vera Marjanović, Jeff Z. Pan, Mohit Bansal, Isabelle Augenstein, Jiawei Han, Heng Ji, Manling Li
Venues:
KnowFM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
147–164
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.knowfm-1.12/
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Bibkey:
Cite (ACL):
Wout Teillers and Matias Valdenegro-Toro. 2026. Tricking Open-World Object Recognition Models: Uncertainty in Out-of-Distribution Detection. In Proceedings of the 4th Workshop on Towards Knowledgeable Foundation Models (KnowFM 2026), pages 147–164, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Tricking Open-World Object Recognition Models: Uncertainty in Out-of-Distribution Detection (Teillers & Valdenegro-Toro, KnowFM 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.knowfm-1.12.pdf