OpenIDC: Reconstructing the Evidence Chain for Lightweight Image Difference Captioning

Jiabao Du, Saihui Hou, Yuan Liu, Jiawei Wang, Yongzhen Huang


Abstract
Image Difference Captioning (IDC) has produced many task-specific models, but their gains are often entangled with isolated implementations, data processing, training protocols, and evaluation settings. As a result, the field accumulates method-level scores more easily than reusable structural evidence. This paper proposes OpenIDC, a flexible and extensible codebase that reconstructs a unified evidence chain for lightweight task-specific IDC. OpenIDC standardizes data pipelines, model interfaces, training strategies, and evaluation protocols, enabling 8 representative method families with 9 executable variants across 3 benchmarks to be reproduced, compared, decomposed, and diagnosed under consistent conditions. Beyond reproduction, OpenIDC advances IDC from final-score comparison to normalized design-space diagnosis. Based on this diagnosis, we introduce SIDFormer, a compact Spatially-guided Invariant-Difference Transformer that serves as a structural answer to lightweight IDC by organizing spatial anchoring, pseudo-change suppression, and reliable difference evidence through functional fusion. Experiments show improved reproducibility and comparability, together with competitive SIDFormer performance across the evaluated benchmarks. Code, reproduced methods, and models will be released.
Anthology ID:
2026.findings-emnlp.1209
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:
25516–25529
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1209/
DOI:
Bibkey:
Cite (ACL):
Jiabao Du, Saihui Hou, Yuan Liu, Jiawei Wang, and Yongzhen Huang. 2026. OpenIDC: Reconstructing the Evidence Chain for Lightweight Image Difference Captioning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 25516–25529, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
OpenIDC: Reconstructing the Evidence Chain for Lightweight Image Difference Captioning (Du et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1209.pdf