A method to pan-sharpen SAR amplitude data via electromagnetic reflectance similarities

ABSTRACT

For a long time, the idea of fusing synthetic radar imagery (SAR) and higher-resolution panchromatic imagery, with the aim of increasing the spatial resolution of radar imagery, has been conceived as impossible. The challenge is due to the different natures of microwave radiation and visible radiation, where the former is the spectrum of SAR imagery, and the latter is of panchromatic imagery. Average reflection amplitude, which constitutes pixel values on both panchromatic and SAR imagery, is taken as a common framework around which this study proposes a method that enables the translation of an array on a panchromatic spectrum into an array of C-band microwave spectrum in order to achieve a higher spatial resolution. In this regard, open-access Worldview-2 and Worldview-3 panchromatic and Sentinel-1 (amplitude-only) images are used. The outputs are qualified using spatial correlation coefficient (SCC), net histogram curve, and R² difference, and Erreur relative globale adimensionnelle de synthese (ERGAS) as full-reference image quality assessment methods in various scenarios. The results are tenable enough to consider this method for ordinary earth observation and monitoring objectives.

KEYWORDS:

• SAR
• spatial resolution
• panchromatic
• pan sharpening

Acknowledgements

The authors are grateful to the European Space Agency and Maxar Technologies for providing free and open access to the Sentinel-1 and Worldview-2 datasets.

Moreover, the authors express their deep sense of gratitude to the journal’s editorial department and the anonymous reviewers.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data Availability statement

Data and algorithms that support the findings of this study are openly available in: ‘Sudoku pan-sharpening method’ at: http://dx.doi.org/10.17632/ps98d5j7s2.1

The satellite images as well as the proposed computer program (Ipython Jupyter file) that are used for this study are included in the repository. This helps enthusiasts remake and validate the research scenario.

Notes

1. Top-left coordinates: 1279342.51422, 6134367.19054 - Bottom-right coordinates: 1282745.0551, 6132070.6082 - EPSG: 3857/WGS 1984 – Pseudo Mercator.

2. Top-left coordinates: 1315146.9410, 6162699.9133 - Bottom-right coordinates: 1318719.9975, 6165111.3258 EPSG: 3857/WGS 1984 – Pseudo Mercator.

3. Copyright: Satellite Imagery © Maxar Technologies 2020–21 Provided by European Space Imaging

4. Copyright: Copernicus Sentinel data 2020–21, processed by ESA.

5. The satellite images as well as the proposed computer program (Ipython Jupyter file) that are used for this study are included in the provided repository. This helps enthusiasts scrutinize the code and remake and validate the research as they prefer.

Additional information

Funding

This research was entirely done without any funding from no external source. The authors did not receive support from any organization for the submitted work.