A comparison of 3D MWT Reconstruction Models for UAV-based GPR

Ground Penetrating Radar (GPR) [1-2] is a well-established geophysical technique for high-resolution subsurface investigations and is increasingly integrated with UAV platforms to enable rapid, flexible, and non-invasive surveys [3]. This contribution presents a comparative analysis of two three-dimensional microwave tomography (MWT) approaches for processing UAV-GPR multimonostatic data. The approaches differ for the adopted scattering model: the Interface Reflection Point 3D (IRP3D) model [4-5] and the Equivalent Permittivity 3D (EP3D) model, previously proposed for 2D imaging in [6]. The approaches are compared in terms of spatial resolution by inverting full-wave simulated data referred to a point like scatterer and the effect of data spacing as well as the irregular distribution is examined. Experimental data collected in laboratory-controlled conditions are considered to validate the expected performance. Furthermore, results referred to on field data acquired at the Altopiano di Verteglia (Avellino, Italy), are provided. The reconstruction capabilities are quantitatively assessed through image-based metrics, including image contrast and entropy, highlighting strengths and limitations of each approach. The results provide insights into the suitability of advanced 3D MWT algorithms for UAV-supported GPR surveys and contribute to the development of robust processing workflows for drone-based subsurface imaging.

[1] D. J. Daniels, Ground Penetrating Radar. Hoboken, NJ: Wiley, 2005.

[2] R. Persico, Introduction to Ground Penetrating Radar: Inverse Scattering and Data Processing. Hoboken, NJ: Wiley, 2014.

[3] C. Noviello, G. Gennarelli, G. Esposito, G. Ludeno, G. Fasano, L. Capozzoli, F. Soldovieri, I. Catapano, “An Overview on Down-Looking UAV-Based GPR Systems,” in Remote Sensing, 2022, 14(14):3245. https://doi.org/10.3390/rs14143245.

[4] G. Gennarelli, C. Noviello, G. Ludeno, G. Esposito, F. Soldovieri and I. Catapano, "Three-Dimensional Ray-Based Tomographic Approach for Contactless GPR Imaging," in IEEE Transactions on Geoscience and Remote Sensing, vol. 61, pp. 1-14, 2023, Art no. 2000614, doi: 10.1109/TGRS.2023.3250740.

[5] G. Esposito, G. Gennarelli, F. Soldovieri and I. Catapano, "Effective 3-D Contactless GPR Imaging: Experimental Validation," in IEEE Geoscience and Remote Sensing Letters, vol. 21, pp. 1-5, 2024, Art no. 3509005, doi: 10.1109/LGRS.2024.3451729.

[6] G. Ludeno, L. Capozzoli, E. Rizzo, F. Soldovieri, I. Catapano, “A Microwave Tomography Strategy for Underwater Imaging via Ground Penetrating Radar,” in Remote Sensing, 2018, 10, 1410. https://doi.org/10.3390/rs10091410.