Beyond Backscatter: InSAR coherence from detected SAR images
Summary
A deep learning framework is proposed for coherence regression directly from detected Synthetic Aperture Radar (SAR) images, eliminating the need for accurate coregistration. This Residual U-Net model, trained on 12-day Sentinel-1 Single-Look Complex (SLC) pairs, learns the relationship between backscatter magnitudes and coherence. The framework demonstrates strong generalization across diverse datasets, including different temporal baselines (0, 6, 12, and 36 days), geographic locations (e.g., San Francisco Bay, Atacama Desert), polarizations (VV to VH), and even operative frequencies (Sentinel-1 C-band to ALOS L-band). It consistently outperforms existing intensity-based methods, achieving an RMSE of 0.108 on a 12-day Sentinel-1 test over the San Francisco Bay area. The method also successfully adapts to globally available analysis-ready Sentinel-1 Ground Range Detected (GRD) products from Google Earth Engine, enabling large-scale applications in change monitoring and mapping.
Key takeaway
For Machine Learning Engineers developing SAR applications, if you require interferometric coherence maps but want to avoid computationally intensive SLC coregistration, this deep learning framework offers a viable alternative. You can utilize detected SAR products, including Google Earth Engine GRD data, to generate high-resolution coherence, significantly accelerating large-scale change monitoring and mapping tasks. Consider fine-tuning for specific sensor or frequency domains to optimize performance.
Key insights
Deep learning can accurately regress InSAR coherence from detected SAR images, bypassing complex coregistration.
Principles
- Coherence estimation can bypass subpixel coregistration.
- Paired backscatter observations contain coherence cues.
- Deep learning models generalize across SAR acquisition conditions.
Method
A Residual U-Net is trained on coregistered SLC coherence maps, using detected backscatter pairs as input, then fine-tuned for GRD products with spatial multilooking and radiometric normalization.
In practice
- Use detected SAR for rapid coherence screening.
- Apply to Google Earth Engine GRD for large-scale monitoring.
- Extend coherence-based analysis to non-nominal SAR data.
Topics
- InSAR Coherence Estimation
- Deep Learning
- SAR Image Analysis
- Sentinel-1 GRD
- Google Earth Engine
- Residual U-Net
Best for: Computer Vision Engineer, AI Scientist, Machine Learning Engineer, Research Scientist
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Editorial summary, takeaway, and curation by AIssential. Original article published by cs.CV updates on arXiv.org.