Visual Fact Checker: Enabling High-Fidelity Detailed Caption Generation
Authors: Yunhao Ge, Xiaohui Zeng, Jacob Samuel Huffman, Tsung-Yi Lin, Ming-Yu Liu, Yin Cui

Existing automatic captioning methods for visual content face challenges such as lack of detail content hallucination and poor instruction following. In this work we propose VisualFactChecker (VFC) a flexible training-free pipeline that generates high-fidelity and detailed captions for both 2D images and 3D objects. VFC consists of three steps: 1) proposal where image-to-text captioning models propose multiple initial captions; 2) verification where a large language model (LLM) utilizes tools such as object detection and VQA models to fact-check proposed captions; 3) captioning where an LLM generates the final caption by summarizing caption proposals and the fact check verification results. In this step VFC can flexibly generate captions in various styles following complex instructions. We conduct comprehensive captioning evaluations using four metrics: 1) CLIP-Score for image-text similarity; 2) CLIP-Image-Score for measuring the image-image similarity between the original and the reconstructed image generated by a text-to-image model using the caption. 3) human study on Amazon Mechanical Turk; 4) GPT-4V for fine-grained evaluation. Evaluation results show that VFC outperforms state-of-the-art open-sourced captioning methods for 2D images on the COCO dataset and 3D assets on the Objaverse dataset. Our study demonstrates that by combining open-source models into a pipeline we can attain captioning capability comparable to proprietary models such as GPT-4V despite being over 10x smaller in model size.