HalDec-Bench: Benchmarking Hallucination Detector in Image Captioning

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Saito, Kuniaki, Shinoda, Risa, Tanaka, Shohei, Hirasawa, Tosho, Okura, Fumio, Ushiku, Yoshitaka
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914416213098496
author Saito, Kuniaki
Shinoda, Risa
Tanaka, Shohei
Hirasawa, Tosho
Okura, Fumio
Ushiku, Yoshitaka
author_facet Saito, Kuniaki
Shinoda, Risa
Tanaka, Shohei
Hirasawa, Tosho
Okura, Fumio
Ushiku, Yoshitaka
contents Hallucination detection in captions (HalDec) assesses a vision-language model's ability to correctly align image content with text by identifying errors in captions that misrepresent the image. Beyond evaluation, effective hallucination detection is also essential for curating high-quality image-caption pairs used to train VLMs. However, the generalizability of VLMs as hallucination detectors across different captioning models and hallucination types remains unclear due to the lack of a comprehensive benchmark. In this work, we introduce HalDec-Bench, a benchmark designed to evaluate hallucination detectors in a principled and interpretable manner. HalDec-Bench contains captions generated by diverse VLMs together with human annotations indicating the presence of hallucinations, detailed hallucination-type categories, and segment-level labels. The benchmark provides tasks with a wide range of difficulty levels and reveals performance differences across models that are not visible in existing multimodal reasoning or alignment benchmarks. Our analysis further uncovers two key findings. First, detectors tend to recognize sentences appearing at the beginning of a response as correct, regardless of their actual correctness. Second, our experiments suggest that dataset noise can be substantially reduced by using strong VLMs as filters while employing recent VLMs as caption generators. Our project page is available at https://dahlian00.github.io/HalDec-Bench-Page/.
format Preprint
id arxiv_https___arxiv_org_abs_2603_15253
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle HalDec-Bench: Benchmarking Hallucination Detector in Image Captioning
Saito, Kuniaki
Shinoda, Risa
Tanaka, Shohei
Hirasawa, Tosho
Okura, Fumio
Ushiku, Yoshitaka
Computer Vision and Pattern Recognition
Hallucination detection in captions (HalDec) assesses a vision-language model's ability to correctly align image content with text by identifying errors in captions that misrepresent the image. Beyond evaluation, effective hallucination detection is also essential for curating high-quality image-caption pairs used to train VLMs. However, the generalizability of VLMs as hallucination detectors across different captioning models and hallucination types remains unclear due to the lack of a comprehensive benchmark. In this work, we introduce HalDec-Bench, a benchmark designed to evaluate hallucination detectors in a principled and interpretable manner. HalDec-Bench contains captions generated by diverse VLMs together with human annotations indicating the presence of hallucinations, detailed hallucination-type categories, and segment-level labels. The benchmark provides tasks with a wide range of difficulty levels and reveals performance differences across models that are not visible in existing multimodal reasoning or alignment benchmarks. Our analysis further uncovers two key findings. First, detectors tend to recognize sentences appearing at the beginning of a response as correct, regardless of their actual correctness. Second, our experiments suggest that dataset noise can be substantially reduced by using strong VLMs as filters while employing recent VLMs as caption generators. Our project page is available at https://dahlian00.github.io/HalDec-Bench-Page/.
title HalDec-Bench: Benchmarking Hallucination Detector in Image Captioning
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.15253