Syn-Omni: Structured Specialization and Progressive Collaboration for Omnimodal Embeddings

Youngtaek Oh, Qiyu Wu, Hiromi Wakaki, Junmo Kim, Yuki Mitsufuji


Abstract
Omnimodal embeddings naturally involve both shared representations and modality-specific features across heterogeneous inputs. However, existing omnimodal embedding methods often rely on a single shared parameter space over mixed-modality data, limiting structural separation between universal and modality-specific representations. To address this, we propose Syn-Omni, a unified framework for structured omnimodal adaptation with modality specialization and controlled cross-modal collaboration. Specifically, we introduce Orthogonal Modality-Expert LoRA (OME-LoRA), which decomposes adaptation into a shared LoRA path for universal semantics and modality-expert LoRA paths for modality-aware specialization. Furthermore, Progressive Synergy Routing (PSR) enables experts to first establish modality-specific priors, then gradually interact with other modality-experts for cross-modal synergy. Evaluated across 81 diverse tasks spanning image, video, audio, and audiovisual modalities, Syn-Omni consistently outperforms omnimodal baselines, demonstrating the effectiveness of structured specialization and cross-modal progressive collaboration.
Anthology ID:
2026.findings-emnlp.1178
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:
24889–24915
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1178/
DOI:
Bibkey:
Cite (ACL):
Youngtaek Oh, Qiyu Wu, Hiromi Wakaki, Junmo Kim, and Yuki Mitsufuji. 2026. Syn-Omni: Structured Specialization and Progressive Collaboration for Omnimodal Embeddings. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 24889–24915, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Syn-Omni: Structured Specialization and Progressive Collaboration for Omnimodal Embeddings (Oh et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1178.pdf