Journal Article

·2026

X-Change: An RGB-Inspired Spectral-Aware Framework for Multitask and Explainable Change Captioning

Busra Tuzlupinar YTU , M. Fatih Amasyali YTU , Ali Can Karaca YTU

IEEE Geoscience and Remote Sensing Letters

Abstract

Remote sensing change captioning describes land surface changes between bi-temporal images. However, models trained on RGB inputs often underperform compared to multispectral (MS) counterparts due to limited spectral awareness. We present X-Change, an RGB-inspired spectral-aware framework that achieves MS-level descriptive quality while jointly performing multi-task segmentation to predict change, NDVI, and NDWI masks—indicating where and how change occurs. Unlike prior RGB-based methods, X-Change employs rule-based spectral supervision from bi-temporal Sentinel-2 data, enabling its shared encoder to internalize NDVI/NDWI-related cues for both captioning and segmentation tasks. Experiments on the MOSAIC-SEN2-CC dataset show that X-Change surpasses state-of- the-art RGB-based models and matches or slightly exceeds those trained on multispectral inputs, producing spatially consistent change and index maps. Overall, X-Change bridges the gap between RGB and MS modalities, offering an interpretable and practical framework for spectral-aware, multi-task, and explainable change captioning. The codebase will be publicly released at https://github.com/ChangeCapsInRS/X-Change.

Keywords

Closed captioning Multispectral image RGB color model Segmentation Encoder Change detection Codebase Computer science Artificial intelligence

Subject Areas

Remote-Sensing Image Classification ·Media Technology ·Physical Sciences
Geographic Information Systems Studies ·Geography, Planning and Development ·Social Sciences
Remote Sensing in Agriculture ·Ecology ·Physical Sciences

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