LLM-Driven Completeness and Consistency Evaluation for Cultural Heritage Data Augmentation in Cross-Modal Retrieval
Jian Zhang, Junyi Guo, Junyi Yuan, Huanda Lu, Yanlin Zhou, Fangyu Wu, Qiufeng Wang, Dongming Lu
TL;DR
The paper tackles the problem of incomplete and potentially hallucinated textual descriptions in cultural heritage cross-modal retrieval. It introduces C^3, an LLM-driven augmentation framework that enforces completeness via bidirectional coverage and consistency via a Markov decision process-guided Chain-of-Thought sequence, followed by contrastive learning with augmented captions. Key contributions include a formal completeness score S_complete, a CoT-based augmentation pipeline (C1–C4) with MD P supervision, and strong retrieval improvements on CulTi and TimeTravel, as well as competitive zero-shot results on MSCOCO and Flickr30K. The work demonstrates that grounding augmented descriptions in visual evidence and controlling reasoning steps can substantially reduce hallucinations while boosting multimodal alignment, with implications for digital preservation and museum analytics.
Abstract
Cross-modal retrieval is essential for interpreting cultural heritage data, but its effectiveness is often limited by incomplete or inconsistent textual descriptions, caused by historical data loss and the high cost of expert annotation. While large language models (LLMs) offer a promising solution by enriching textual descriptions, their outputs frequently suffer from hallucinations or miss visually grounded details. To address these challenges, we propose $C^3$, a data augmentation framework that enhances cross-modal retrieval performance by improving the completeness and consistency of LLM-generated descriptions. $C^3$ introduces a completeness evaluation module to assess semantic coverage using both visual cues and language-model outputs. Furthermore, to mitigate factual inconsistencies, we formulate a Markov Decision Process to supervise Chain-of-Thought reasoning, guiding consistency evaluation through adaptive query control. Experiments on the cultural heritage datasets CulTi and TimeTravel, as well as on general benchmarks MSCOCO and Flickr30K, demonstrate that $C^3$ achieves state-of-the-art performance in both fine-tuned and zero-shot settings.
