YARD: Y-Architecture Register Decoding for Efficient Hallucination Mitigation in Large Vision-Language Models

Ting Chen, Geng Li, Guohao Chen, Yu Hu, Guan Huang, Mai Chen, Langsheng Lei, Yongyong Lin


Abstract
Contrastive decoding (CD) seeks to mitigate hallucinations in Large Vision-Language Models (LVLMs) by contrasting the output distributions of a standard model and a visually degraded model. However, existing training-free CD methods suffer from sub-optimal degraded branches: completely dropping visual tokens is too extreme and induces language hallucinations, while corrupting input images offers coarse control over visual evidence and suffers from high inference latency due to requiring two full forward passes. To address these dilemmas, we propose YARD, a training-free Y-Architecture Register Decoding framework. Motivated by the observation that reliable text-to-vision grounding predominantly emerges in the middle decoder layers, YARD constructs the degraded branch internally by sharing shallow-layer computations and branching exactly at this critical stage. For the degraded branch, YARD replaces patch-level visual tokens with register tokens, which preserve global image semantics but lack fine-grained local evidence. This image-aware yet locally under-grounded design provides a faithful contrastive signal without extreme modality mismatch, while the Y-architecture strictly avoids a costly second forward pass. Extensive experiments on generative and discriminative hallucination benchmarks demonstrate that YARD consistently achieves state-of-the-art hallucination mitigation across multiple LVLMs, alongside a significant reduction in inference latency.
Anthology ID:
2026.emnlp-main.298
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
6864–6885
Language:
URL:
https://aclanthology.org/2026.emnlp-main.298/
DOI:
Bibkey:
Cite (ACL):
Ting Chen, Geng Li, Guohao Chen, Yu Hu, Guan Huang, Mai Chen, Langsheng Lei, and Yongyong Lin. 2026. YARD: Y-Architecture Register Decoding for Efficient Hallucination Mitigation in Large Vision-Language Models. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 6864–6885, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
YARD: Y-Architecture Register Decoding for Efficient Hallucination Mitigation in Large Vision-Language Models (Chen et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.298.pdf