Flow matching for Sentinel-2 super-resolution: implementation, application, and implications

TL;DR

This paper introduces a flow matching model for Sentinel-2 super-resolution, achieving high accuracy and perceptual quality efficiently, enabling large-scale high-resolution satellite imagery generation and land cover classification.

Contribution

The work presents a novel flow matching approach for satellite image super-resolution, outperforming diffusion and GAN models in accuracy and efficiency, with practical applications in large-scale land cover mapping.

Findings

Flow matching outperforms diffusion and Real-ESRGAN in pixel accuracy.

The model generates perceptually realistic images in 20 steps with a second-order solver.

Achieved 89.11% accuracy in land cover classification for the Chesapeake Bay watershed.

Abstract

Developing robust techniques for super-resolution of satellite imagery involves navigating commonly observed trade-offs between spectral fidelity and perceptual quality. In this work, we introduce a flow matching model for 4x super-resolution of 10-m Sentinel-2 visible and near-infrared bands over the conterminous United States (CONUS) using a dataset of 120,851 10-m Sentinel-2 and 2.5-m resampled NAIP imagery pairs acquired on the same day. Our results showed that the flow matching model outperformed diffusion and Real-ESRGAN models in pixel-wise accuracy in a single sampling step using the Euler method. When evaluated with a second-order Midpoint solver, our model generated perceptually realistic super-resolved imagery in only 20 sampling steps, effectively navigating the perception-distortion trade-off at inference time without retraining. We used this model to produce a super-resolved 2.5-m 4-band CONUS imagery product derived from 2025 10-m Sentinel-2 annual composites, consisting of over 1.58 trillion pixels. We further evaluated the use of super-resolved data on a land cover classification task using semantic segmentation models. Finally, we generated a yearly 2.5-m land cover product for the Chesapeake Bay watershed for 2020-2025. An accuracy assessment against 25,000 ground truth points revealed an overall accuracy of 89.11% for the annual land cover product. We conclude that flow matching is an effective generative modeling approach for super-resolution of Sentinel-2 imagery compared to diffusion and Generative Adversarial Network-based methods, and has strong implications for expanding access to high-resolution imagery for geospatial applications that demand fine spatial detail.