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MM-OVSeg:Multimodal Optical-SAR Fusion for Open-Vocabulary Segmentation in Remote Sensing

arXiv cs.CV / 3/19/2026

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Key Points

  • MM-OVSeg is introduced as a multimodal Optical-SAR fusion framework designed for resilient open-vocabulary segmentation in remote sensing, capable of operating under cloudy or haze-contaminated conditions.
  • The method features a cross-modal unification process to align representations across sensors and a dual-encoder fusion module that integrates hierarchical features from multiple vision foundation models for text-aligned segmentation.
  • Extensive experiments show improved robustness and generalization across diverse cloud conditions, addressing the cross-modal domain gap and dense prediction challenges of current vision-language models.
  • The framework leverages optical imagery for rich spectral semantics while exploiting SAR's cloud-penetrating structural cues, and the authors release the source dataset and code.

Abstract

Open-vocabulary segmentation enables pixel-level recognition from an open set of textual categories, allowing generalization beyond fixed classes. Despite great potential in remote sensing, progress in this area remains largely limited to clear-sky optical data and struggles under cloudy or haze-contaminated conditions. We present MM-OVSeg, a multimodal Optical-SAR fusion framework for resilient open-vocabulary segmentation under adverse weather conditions. MM-OVSeg leverages the complementary strengths of the two modalities--optical imagery provides rich spectral semantics, while synthetic aperture radar (SAR) offers cloud-penetrating structural cues. To address the cross-modal domain gap and the limited dense prediction capability of current vision-language models, we propose two key designs: a cross-modal unification process for multi-sensor representation alignment, and a dual-encoder fusion module that integrates hierarchical features from multiple vision foundation models for text-aligned multimodal segmentation. Extensive experiments demonstrate that MM-OVSeg achieves superior robustness and generalization across diverse cloud conditions. The source dataset and code are available here.