SOTAlign: Semi-Supervised Alignment of Unimodal Vision and Language Models via Optimal Transport

Fuente: arXiv
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Main Authors: Roschmann, Simon, Krzakala, Paul, Mazelet, Sonia, Bouniot, Quentin, Akata, Zeynep
Format: Preprint
Published: 2026
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author Roschmann, Simon
Krzakala, Paul
Mazelet, Sonia
Bouniot, Quentin
Akata, Zeynep
author_facet Roschmann, Simon
Krzakala, Paul
Mazelet, Sonia
Bouniot, Quentin
Akata, Zeynep
contents The Platonic Representation Hypothesis posits that neural networks trained on different modalities converge toward a shared statistical model of the world. Recent work exploits this convergence by aligning frozen pretrained vision and language models with lightweight alignment layers, but typically relies on contrastive losses and millions of paired samples. In this work, we ask whether meaningful alignment can be achieved with substantially less supervision. We introduce a semi-supervised setting in which pretrained unimodal encoders are aligned using a small number of image-text pairs together with large amounts of unpaired data. To address this challenge, we propose SOTAlign, a two-stage framework that first recovers a coarse shared geometry from limited paired data using a linear teacher, then refines the alignment on unpaired samples via an optimal-transport-based divergence that transfers relational structure without overconstraining the target space. Unlike existing semi-supervised methods, SOTAlign effectively leverages unpaired images and text, learning robust joint embeddings across datasets and encoder pairs, and significantly outperforming supervised and semi-supervised baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2602_23353
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle SOTAlign: Semi-Supervised Alignment of Unimodal Vision and Language Models via Optimal Transport
Roschmann, Simon
Krzakala, Paul
Mazelet, Sonia
Bouniot, Quentin
Akata, Zeynep
Machine Learning
Artificial Intelligence
The Platonic Representation Hypothesis posits that neural networks trained on different modalities converge toward a shared statistical model of the world. Recent work exploits this convergence by aligning frozen pretrained vision and language models with lightweight alignment layers, but typically relies on contrastive losses and millions of paired samples. In this work, we ask whether meaningful alignment can be achieved with substantially less supervision. We introduce a semi-supervised setting in which pretrained unimodal encoders are aligned using a small number of image-text pairs together with large amounts of unpaired data. To address this challenge, we propose SOTAlign, a two-stage framework that first recovers a coarse shared geometry from limited paired data using a linear teacher, then refines the alignment on unpaired samples via an optimal-transport-based divergence that transfers relational structure without overconstraining the target space. Unlike existing semi-supervised methods, SOTAlign effectively leverages unpaired images and text, learning robust joint embeddings across datasets and encoder pairs, and significantly outperforming supervised and semi-supervised baselines.
title SOTAlign: Semi-Supervised Alignment of Unimodal Vision and Language Models via Optimal Transport
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.23353