Exploiting the Asymmetric Uncertainty Structure of Pre-trained VLMs on the Unit Hypersphere

Fuente: arXiv
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Auteurs principaux: Ju, Li, Andersson, Max, Fredriksson, Stina, Glöckner, Edward, Hellander, Andreas, Vats, Ekta, Singh, Prashant
Format: Preprint
Publié: 2025
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author Ju, Li
Andersson, Max
Fredriksson, Stina
Glöckner, Edward
Hellander, Andreas
Vats, Ekta
Singh, Prashant
author_facet Ju, Li
Andersson, Max
Fredriksson, Stina
Glöckner, Edward
Hellander, Andreas
Vats, Ekta
Singh, Prashant
contents Vision-language models (VLMs) as foundation models have significantly enhanced performance across a wide range of visual and textual tasks, without requiring large-scale training from scratch for downstream tasks. However, these deterministic VLMs fail to capture the inherent ambiguity and uncertainty in natural language and visual data. Recent probabilistic post-hoc adaptation methods address this by mapping deterministic embeddings onto probability distributions; however, existing approaches do not account for the asymmetric uncertainty structure of the modalities, and the constraint that meaningful deterministic embeddings reside on a unit hypersphere, potentially leading to suboptimal performance. In this paper, we address the asymmetric uncertainty structure inherent in textual and visual data, and propose AsymVLM to build probabilistic embeddings from pre-trained VLMs on the unit hypersphere, enabling uncertainty quantification. We validate the effectiveness of the probabilistic embeddings on established benchmarks, and present comprehensive ablation studies demonstrating the inherent nature of asymmetry in the uncertainty structure of textual and visual data.
format Preprint
id arxiv_https___arxiv_org_abs_2505_11029
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exploiting the Asymmetric Uncertainty Structure of Pre-trained VLMs on the Unit Hypersphere
Ju, Li
Andersson, Max
Fredriksson, Stina
Glöckner, Edward
Hellander, Andreas
Vats, Ekta
Singh, Prashant
Machine Learning
Vision-language models (VLMs) as foundation models have significantly enhanced performance across a wide range of visual and textual tasks, without requiring large-scale training from scratch for downstream tasks. However, these deterministic VLMs fail to capture the inherent ambiguity and uncertainty in natural language and visual data. Recent probabilistic post-hoc adaptation methods address this by mapping deterministic embeddings onto probability distributions; however, existing approaches do not account for the asymmetric uncertainty structure of the modalities, and the constraint that meaningful deterministic embeddings reside on a unit hypersphere, potentially leading to suboptimal performance. In this paper, we address the asymmetric uncertainty structure inherent in textual and visual data, and propose AsymVLM to build probabilistic embeddings from pre-trained VLMs on the unit hypersphere, enabling uncertainty quantification. We validate the effectiveness of the probabilistic embeddings on established benchmarks, and present comprehensive ablation studies demonstrating the inherent nature of asymmetry in the uncertainty structure of textual and visual data.
title Exploiting the Asymmetric Uncertainty Structure of Pre-trained VLMs on the Unit Hypersphere
topic Machine Learning
url https://arxiv.org/abs/2505.11029