Production and Calibration of a Lambertian Surface Based on Barium Sulfate (BaSO₄) for the Calibration of Multispectral Cameras

Abstract

Drones, or unmanned aerial vehicles (UAVs), are increasingly utilized across diverse fields such as agriculture, environmental analysis, and engineering due to their ability to capture high-quality multispectral imagery. To ensure the accuracy of these images, radiometric calibration of onboard multispectral cameras is essential. This study aimed to develop and calibrate a low-cost Lambertian surface using barium sulfate (BaSO₄) for radiometric calibration of UAV-mounted multispectral cameras. A stainless steel mold was designed to compact BaSO₄, and the resulting surface was calibrated using an ASD FieldSpec HandHeld UV/NIR spectroradiometer and a Spectralon plate as the reference standard. Results showed a strong correlation (Pearson’s r = 0.9988) between the BaSO₄ surface and the Spectralon plate, confirming that the BaSO₄-based surface is a cost-effective alternative for producing diffuse Lambertian surfaces with performance comparable to the standard.

Keywords

UAV / Multispectral / Surface / Diffuse

Acknowledgements

To my colleague Gabriela Zanchetta, a PhD student in the Postgraduate Course in Cartographic Sciences at UNESP —Presidente Prudente, for her support and guidance in using the ASD FieldSpec HandHeld UV/NIR spectroradiometer and Spectralon plate. To Fábio Larini, owner of the company WD Tron, for his support in the project. To the Brazilian Center for UAVs for Aerolifting—NUBRAVA, for his support of the project.

Author Contributions

Conceptualization and Writing, D.C.G.; Methodology and Supervision, A.R.E.; Software, F.S.Y.W.; Review, H.d.S.F., E.L.P.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data supporting the findings of this study are available from upon reasonable request.

Funding

This research received no external funding.

Competing Interest Statement

The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this article.

AI Usage Statement

During the preparation of this work, the authors used ChatGPT-4 to improve readability and language. After using this tool/service, the authors reviewed and edited the content as necessary and assume full responsibility for the content of the publication.

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