Vision Language Model Helps Private Information De-Identification in Vision Data

Tiejin Chen, Pingzhi Li, Kaixiong Zhou, Tianlong Chen, Hua Wei


Abstract
Visual Language Models (VLMs) have gained significant popularity due to their remarkable ability. While various methods exist to enhance privacy in text-based applications, privacy risks associated with visual inputs remain largely overlooked such as Protected Health Information (PHI) in medical images. To tackle this problem, two key tasks: accurately localizing sensitive text and processing it to ensure privacy protection should be performed. To address this issue, we introduce VisShield (Vision Privacy Shield), an end-to-end framework designed to enhance the privacy awareness of VLMs. Our framework consists of two key components: a specialized instruction-tuning dataset OPTIC (Optical Privacy Text Instruction Collection) and a tailored training methodology. The dataset provides diverse privacy-oriented prompts that guide VLMs to perform targeted Optical Character Recognition (OCR) for precise localization of sensitive text, while the training strategy ensures effective adaptation of VLMs to privacy-preserving tasks. Specifically, our approach ensures that VLMs recognize privacy-sensitive text and output precise bounding boxes for detected entities, allowing for effective masking of sensitive information. Extensive experiments demonstrate that our framework significantly outperforms existing approaches in handling private information, paving the way for privacy-preserving applications in vision-language models.
Anthology ID:
2025.findings-acl.236
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venues:
Findings | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4558–4572
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URL:
https://preview.aclanthology.org/ingestion-acl-25/2025.findings-acl.236/
DOI:
Bibkey:
Cite (ACL):
Tiejin Chen, Pingzhi Li, Kaixiong Zhou, Tianlong Chen, and Hua Wei. 2025. Vision Language Model Helps Private Information De-Identification in Vision Data. In Findings of the Association for Computational Linguistics: ACL 2025, pages 4558–4572, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Vision Language Model Helps Private Information De-Identification in Vision Data (Chen et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/ingestion-acl-25/2025.findings-acl.236.pdf