Semantically Aware Optimal Transport for Dense Label Transfer

Preeti, Kiran Ravish, Ankita Kushwaha, Pawan Kumar


Abstract
Vision foundation models produce features that generalize across visual domains without fine-tuning, yet naively transferring labels through these feature spaces fails under large distribution shifts.We propose SAOT (**S**emantically **A**ware **O**ptimal **T**ransport), which learns a transport cost within a fused unbalanced optimal transport formulation for dense label transfer from frozen vision transformer features to new domains.SAOT combines a learnable appearance metric with semantic class-prototype priors, unbalanced transport for partial matching under distribution shift, and a block-sparse solver for tractable inference.We pair this with a two-stage decoder: an MLP trained on SAOT pseudo-labels, then refined via EMA-teacher self-training with class-balanced sampling.On GTA5Cityscapes with frozen DINOv2 ViT-L/14 features, SAOT+Decoder reaches 25.7% mIoU, a **3.8×** improvement over nearest-neighbor transfer (6.7%), without any backbone adaptation.Per-class results show large gains on spatially coherent classes (road 90.3%, car 76.2%, building 71.5%), demonstrating that learned semantic transport costs capture domain-invariant structure even under severe synthetic-to-real shifts. On VOC trainval with frozen ViT-B/16 features, the full pipeline reaches 47.5% mIoU, indicating that the approach extends beyond synthetic-to-real adaptation.
Anthology ID:
2026.alvr-main.3
Volume:
Proceedings of the 4th Workshop on Advances in Language and Vision Research (ALVR)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Qianqi Yan, Syrielle Montariol, Yue Fan, Jing Gu, Jiayi Pan, Manling Li, Parisa Kordjamshidi, Alane Suhr, Xin Eric Wang
Venues:
ALVR | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
18–45
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.alvr-main.3/
DOI:
Bibkey:
Cite (ACL):
Preeti, Kiran Ravish, Ankita Kushwaha, and Pawan Kumar. 2026. Semantically Aware Optimal Transport for Dense Label Transfer. In Proceedings of the 4th Workshop on Advances in Language and Vision Research (ALVR), pages 18–45, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Semantically Aware Optimal Transport for Dense Label Transfer (Preeti et al., ALVR 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.alvr-main.3.pdf