Prompting Foundation Models for Zero-Shot Ship Instance Segmentation in SAR Imagery

Fuente: arXiv
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Main Authors: Mansour, Islam, Sica, Francescopaolo, Schmitt, Michael
Format: Preprint
Published: 2026
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author Mansour, Islam
Sica, Francescopaolo
Schmitt, Michael
author_facet Mansour, Islam
Sica, Francescopaolo
Schmitt, Michael
contents Synthetic Aperture Radar (SAR) plays a critical role in maritime surveillance, yet deep learning for SAR analysis is limited by the lack of pixel-level annotations. This paper explores how general-purpose vision foundation models can enable zero-shot ship instance segmentation in SAR imagery, eliminating the need for pixel-level supervision. A YOLOv11-based detector trained on open SAR datasets localizes ships via bounding boxes, which then prompt the Segment Anything Model 2 (SAM2) to produce instance masks without any mask annotations. Unlike prior SAM-based SAR approaches that rely on fine tuning or adapters, our method demonstrates that spatial constraints from a SAR-trained detector alone can effectively regularize foundation model predictions. This design partially mitigates the optical-SAR domain gap and enables downstream applications such as vessel classification, size estimation, and wake analysis. Experiments on the SSDD benchmark achieve a mean IoU of 0.637 (89% of a fully supervised baseline) with an overall ship detection rate of 89.2%, confirming a scalable, annotation-efficient pathway toward foundation-model-driven SAR image understanding.
format Preprint
id arxiv_https___arxiv_org_abs_2604_17920
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Prompting Foundation Models for Zero-Shot Ship Instance Segmentation in SAR Imagery
Mansour, Islam
Sica, Francescopaolo
Schmitt, Michael
Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
Synthetic Aperture Radar (SAR) plays a critical role in maritime surveillance, yet deep learning for SAR analysis is limited by the lack of pixel-level annotations. This paper explores how general-purpose vision foundation models can enable zero-shot ship instance segmentation in SAR imagery, eliminating the need for pixel-level supervision. A YOLOv11-based detector trained on open SAR datasets localizes ships via bounding boxes, which then prompt the Segment Anything Model 2 (SAM2) to produce instance masks without any mask annotations. Unlike prior SAM-based SAR approaches that rely on fine tuning or adapters, our method demonstrates that spatial constraints from a SAR-trained detector alone can effectively regularize foundation model predictions. This design partially mitigates the optical-SAR domain gap and enables downstream applications such as vessel classification, size estimation, and wake analysis. Experiments on the SSDD benchmark achieve a mean IoU of 0.637 (89% of a fully supervised baseline) with an overall ship detection rate of 89.2%, confirming a scalable, annotation-efficient pathway toward foundation-model-driven SAR image understanding.
title Prompting Foundation Models for Zero-Shot Ship Instance Segmentation in SAR Imagery
topic Computer Vision and Pattern Recognition
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2604.17920