Multimodal Reranking for Knowledge-Intensive Visual Question Answering
Haoyang Wen, Honglei Zhuang, Hamed Zamani, Alexander Hauptmann, Michael Bendersky
TL;DR
The paper tackles KI-VQA by augmenting a standard retrieval-and-generation pipeline with a multi-modal reranker that enables cross-item interaction between the question and knowledge candidates. By leveraging a Wikipedia-based image-text dataset and a vision-language Transformer framework, the approach refines candidate relevance before answer reasoning, guided by distant supervision. Experimental results on OK-VQA and A-OKVQA show consistent improvements over retrieval-only baselines and reveal a training-testing discrepancy: noisier training data can improve robustness when test-time candidates are noisy. The work highlights an upper-bound potential via oracle ranking and points to future directions in memory-efficient multi-modal reasoning and broader applicability to vision-language tasks.
Abstract
Knowledge-intensive visual question answering requires models to effectively use external knowledge to help answer visual questions. A typical pipeline includes a knowledge retriever and an answer generator. However, a retriever that utilizes local information, such as an image patch, may not provide reliable question-candidate relevance scores. Besides, the two-tower architecture also limits the relevance score modeling of a retriever to select top candidates for answer generator reasoning. In this paper, we introduce an additional module, a multi-modal reranker, to improve the ranking quality of knowledge candidates for answer generation. Our reranking module takes multi-modal information from both candidates and questions and performs cross-item interaction for better relevance score modeling. Experiments on OK-VQA and A-OKVQA show that multi-modal reranker from distant supervision provides consistent improvements. We also find a training-testing discrepancy with reranking in answer generation, where performance improves if training knowledge candidates are similar to or noisier than those used in testing.
