Grounded Multimodal In-Context Learning for Product Weight Estimation at Scale in E-commerce

Bhavuk Singhal, Arsh Keshari, Ravindra Kumar Yadav


Abstract
Accurately inferring implicit physical attributes of products, such as weight, is critical for large-scale e-commerce logistics but challenging due to sparse or unreliable textual metadata and high visual variability. We formulate weight estimation as a grounded multimodal reasoning problem and investigate whether large vision-language models (LVLMs) can infer discretized weight buckets through in-context learning (ICL) over product images and descriptions. We introduce a scalable inference framework that conditions predictions on automatically retrieved, category-specific exemplars and propose a distribution-calibrated retrieval strategy that aligns few-shot contexts with the empirical weight distribution of each product sub-category. This calibration substantially improves few-shot multimodal reasoning compared to random or embedding-based retrieval baselines. Across 14 high-variance categories, our approach significantly outperforms strong multimodal KNN baselines in both exact-match accuracy and near-bucket reliability. Deployed in production on a large e-commerce platform, our system processes millions of listings daily and reduces shipping-related revenue leakage by 22%, demonstrating that multimodal ICL can serve as a practical and cost-effective alternative to manual or hardware-based verification.
Anthology ID:
2026.acl-industry.41
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Yunyao Li, Georg Rehm, Mei Tu
Venue:
ACL
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Publisher:
Association for Computational Linguistics
Note:
Pages:
592–603
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-industry.41/
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Cite (ACL):
Bhavuk Singhal, Arsh Keshari, and Ravindra Kumar Yadav. 2026. Grounded Multimodal In-Context Learning for Product Weight Estimation at Scale in E-commerce. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026), pages 592–603, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Grounded Multimodal In-Context Learning for Product Weight Estimation at Scale in E-commerce (Singhal et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-industry.41.pdf