Uncertainty-Gated Large-Small Model Collaboration for Grounded Multimodal Scene Understanding under Ambiguity

Authors

  • Eric Tam Department of Computer Science, Faculty of Science and Engineering, Hong Kong Chu Hai College, Hong Kong, Hong Kong SAR, China Author
  • Lok-Yin Wong Department of Data Science and Artificial Intelligence, Faculty of Computer and Mathematical Sciences, Hong Kong Polytechnic University, Hong Kong, Hong Kong SAR, China Author

DOI:

https://doi.org/10.66238/f04ent19

Keywords:

Multimodal Scene Understanding, Large Vision-Language Models, Uncertainty Estimation, Model Collaboration, Grounded Visual Reasoning

Abstract

Multimodal scene understanding requires intelligent systems to simultaneously interpret visual environments and comprehend natural language instructions. While contemporary large vision-language models demonstrate remarkable capabilities in complex visual reasoning and grounding, their immense computational requirements prohibit deployment in real-time or resource-constrained scenarios. Conversely, small lightweight models operate efficiently but frequently fail when confronted with highly ambiguous scenes, such as those featuring dense occlusion, semantic overlap, or intricate multi-object spatial relationships. This paper presents a novel uncertainty-gated collaborative framework that dynamically routes inference tasks between a computationally efficient small model and a highly capable large model. The proposed system employs a rigorous uncertainty quantification mechanism within the small model to evaluate epistemic and aleatoric ambiguity in real time. When the calculated uncertainty exceeds a dynamically optimized threshold, the system halts local processing and delegates the complex grounding task to the large model. This approach ensures that routine unambiguous scenes are processed locally with minimal latency, while complex ambiguous scenarios receive the necessary computational resources for accurate resolution. Extensive theoretical analysis and simulated deployment experiments demonstrate that the proposed uncertainty-gated collaboration achieves grounding accuracy commensurate with exclusively utilizing a large model, while reducing overall computational overhead by an average of sixty percent. The findings provide a critical pathway for the sustainable deployment of advanced multimodal artificial intelligence in autonomous systems, robotics, and interactive computational environments.

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Published

2026-10-07