Cost-efficient Active Learning for Referring Image Segmentation and Grounding

Junbeom Hong, Seonghoon Yu, Hyung Rok Jung, Sundong Kim, Jeany Son


Abstract
Collecting natural-language referring expressions along with region annotations, such as masks or boxes, is a major bottleneck in visual grounding (VG), as annotators must write descriptions that distinguish target regions from visually similar ones. We tackle this by formulating active learning (AL) for VG under the realistic setting where only raw images are available without accompanying text. Since ground-truth text is unavailable, sample selection must estimate which images contain ambiguous regions that would require discriminative referring expressions. To address this, we generate auxiliary region-text pairs using foundation models, and introduce Referred Region Ambiguity, a new acquisition function that measures whether the model’s confidence collapses onto a single region or disperses across multiple candidates. It allows our method to prioritize images with strong cross-region competition, which are more informative due to their visual ambiguity. We also design a referring-expression annotation interface that helps annotators quickly focus on writing discriminative language with a few clicks. Experiments on RIS and REC benchmarks show that our AL framework consistently outperforms several AL baselines, while a user study shows up to 1.6× faster description labeling of ours.
Anthology ID:
2026.findings-emnlp.1635
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
34765–34788
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1635/
DOI:
10.18653/2026.findings-emnlp.1635
Bibkey:
Cite (ACL):
Junbeom Hong, Seonghoon Yu, Hyung Rok Jung, Sundong Kim, and Jeany Son. 2026. Cost-efficient Active Learning for Referring Image Segmentation and Grounding. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 34765–34788, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Cost-efficient Active Learning for Referring Image Segmentation and Grounding (Hong et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1635.pdf