Open-Set Knowledge-Based Visual Question Answering with Inference Paths

TL;DR

This paper introduces GATHER, a novel retriever-ranker framework for open-set knowledge-based visual question answering that provides explicit reasoning paths and handles questions beyond preset answer corpora.

Contribution

It proposes a new graph-based retrieval and ranking method that enables explainable reasoning paths in open-set KB-VQA, overcoming classification limitations.

Findings

Achieves open-set question answering with explicit reasoning paths.

Outperforms existing models on real-world KB-VQA tasks.

Provides a new dataset, ConceptVQA, with annotated reasoning paths.

Abstract

Given an image and an associated textual question, the purpose of Knowledge-Based Visual Question Answering (KB-VQA) is to provide a correct answer to the question with the aid of external knowledge bases. Prior KB-VQA models are usually formulated as a retriever-classifier framework, where a pre-trained retriever extracts textual or visual information from knowledge graphs and then makes a prediction among the candidates. Despite promising progress, there are two drawbacks with existing models. Firstly, modeling question-answering as multi-class classification limits the answer space to a preset corpus and lacks the ability of flexible reasoning. Secondly, the classifier merely consider "what is the answer" without "how to get the answer", which cannot ground the answer to explicit reasoning paths. In this paper, we confront the challenge of \emph{explainable open-set} KB-VQA, where the system is required to answer questions with entities at wild and retain an explainable reasoning path. To resolve the aforementioned issues, we propose a new retriever-ranker paradigm of KB-VQA, Graph pATH rankER (GATHER for brevity). Specifically, it contains graph constructing, pruning, and path-level ranking, which not only retrieves accurate answers but also provides inference paths that explain the reasoning process. To comprehensively evaluate our model, we reformulate the benchmark dataset OK-VQA with manually corrected entity-level annotations and release it as ConceptVQA. Extensive experiments on real-world questions demonstrate that our framework is not only able to perform open-set question answering across the whole knowledge base but provide explicit reasoning path.