RP-SAM2: Refining Point Prompts for Stable Surgical Instrument Segmentation

Fuente: arXiv
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Main Authors: Zhaksylyk, Nuren, Almakky, Ibrahim, Paranjape, Jay, Vedula, S. Swaroop, Sikder, Shameema, Patel, Vishal M., Yaqub, Mohammad
Format: Preprint
Published: 2025
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author Zhaksylyk, Nuren
Almakky, Ibrahim
Paranjape, Jay
Vedula, S. Swaroop
Sikder, Shameema
Patel, Vishal M.
Yaqub, Mohammad
author_facet Zhaksylyk, Nuren
Almakky, Ibrahim
Paranjape, Jay
Vedula, S. Swaroop
Sikder, Shameema
Patel, Vishal M.
Yaqub, Mohammad
contents Accurate surgical instrument segmentation is essential in cataract surgery for tasks such as skill assessment and workflow optimization. However, limited annotated data makes it difficult to develop fully automatic models. Prompt-based methods like SAM2 offer flexibility yet remain highly sensitive to the point prompt placement, often leading to inconsistent segmentations. We address this issue by introducing RP-SAM2, which incorporates a novel shift block and a compound loss function to stabilize point prompts. Our approach reduces annotator reliance on precise point positioning while maintaining robust segmentation capabilities. Experiments on the Cataract1k dataset demonstrate that RP-SAM2 improves segmentation accuracy, with a 2% mDSC gain, a 21.36% reduction in mHD95, and decreased variance across random single-point prompt results compared to SAM2. Additionally, on the CaDIS dataset, pseudo masks generated by RP-SAM2 for fine-tuning SAM2's mask decoder outperformed those generated by SAM2. These results highlight RP-SAM2 as a practical, stable and reliable solution for semi-automatic instrument segmentation in data-constrained medical settings. The code is available at https://github.com/BioMedIA-MBZUAI/RP-SAM2.
format Preprint
id arxiv_https___arxiv_org_abs_2504_07117
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle RP-SAM2: Refining Point Prompts for Stable Surgical Instrument Segmentation
Zhaksylyk, Nuren
Almakky, Ibrahim
Paranjape, Jay
Vedula, S. Swaroop
Sikder, Shameema
Patel, Vishal M.
Yaqub, Mohammad
Tissues and Organs
Artificial Intelligence
Accurate surgical instrument segmentation is essential in cataract surgery for tasks such as skill assessment and workflow optimization. However, limited annotated data makes it difficult to develop fully automatic models. Prompt-based methods like SAM2 offer flexibility yet remain highly sensitive to the point prompt placement, often leading to inconsistent segmentations. We address this issue by introducing RP-SAM2, which incorporates a novel shift block and a compound loss function to stabilize point prompts. Our approach reduces annotator reliance on precise point positioning while maintaining robust segmentation capabilities. Experiments on the Cataract1k dataset demonstrate that RP-SAM2 improves segmentation accuracy, with a 2% mDSC gain, a 21.36% reduction in mHD95, and decreased variance across random single-point prompt results compared to SAM2. Additionally, on the CaDIS dataset, pseudo masks generated by RP-SAM2 for fine-tuning SAM2's mask decoder outperformed those generated by SAM2. These results highlight RP-SAM2 as a practical, stable and reliable solution for semi-automatic instrument segmentation in data-constrained medical settings. The code is available at https://github.com/BioMedIA-MBZUAI/RP-SAM2.
title RP-SAM2: Refining Point Prompts for Stable Surgical Instrument Segmentation
topic Tissues and Organs
Artificial Intelligence
url https://arxiv.org/abs/2504.07117