Imlaymed: a freeware software for the GPR imaging of stratified soils

In some cases, soils exhibit a layered structure clearly identified even at the depth scales investigated by Ground Penetrating Radar (GPR) surveys. However, not many methods and computational tools are available that systematically address imaging in layered soils. Imlaymed (Imaging in Layered Media) is a Python graphical user interface (GUI) freeware software specifically designed to tackle this problem. The code assumes either a two layered soil or a cavity embedded within a homogeneous soil. In the latter case, the cavity is locally interpreted as a three-layered medium. The interfaces between adjacent layers are assumed smooth—which is geologically reasonable—although not necessarily planar. However, the non-flatness of the layers precludes the possibility of obtaining an analytical solution. Consequently, Imlaymed addresses the focusing and time–depth conversion issues as an imaging problem rather than an inverse scattering problem. The method explicitly accounts for the presence of two distinct propagation velocities within the soil, which results in geometric distortions, including dilation and compression effects on both the targets and the distances among them. Imlaymed aims to mitigate these distortions. The current release represents an initial version of the software, to be progressively updated and extended. Future developments are expected to introduce additional capabilities—e.g. time-reverse migration—and to enhance the existing features, e.g. through the incorporation of AI techniques and the optional use of parallel computing. In particular, Imlaymed will aid to generation of slices directly in the spatial domain instead of the common slices built up in time domain.

The methodology underlying the code is based on our previous results [1-6]. The implementation of this code has improved both the computational efficiency and the ease of use of the algorithms. Notwithstanding, the user of Imlaymed is supposed to have some non-too-basic background experience in GPR prospecting.

Imlaymed is distributed under AUL/ANCL License (Academic Use License/Academic Non-Commercial License).

Acknowledgements

This work has been implemented within the activities of the Research Project “Georadar e avanzamento delle investigazioni: un’applicazione economica alla sicurezza stradale”, financed by University of Calabria.

References

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• Persico et al. “A posteriori insertion of information for focusing and time–depth conversion of ground-penetrating radar data”, Geophysical Prospecting, open access, https://doi.org/10.1111/1365-2478.13369, 2023.
• Persico et al., ­GPR mapping of cavity in complex scenarios with a combined time-depth conversion, Sensors, MDPI, Sensors 2024, 24(10), 3238; https://doi.org/10.3390/s24103238, 2024.
• Persico et al., An innovative time-depth conversion for the management of buried scenarios with strong discontinuities, Journal of Applied Geophysics vol. 227, 105435, DOI 10.1016/j.jappgeo.2024.105435, 2024.
• Yang et al., Accounting for the Different Propagation Velocities for the Focusing and Time–Depth Conversion in a Layered Medium, Applied Sciences 14(24):11812, 2024.
• Persico et al., Retrieving the propagation velocity of the electromagnetic waves in a two-layered medium through the diffraction curves, Near Surface Geophysics, 1–13. https://doi.org/10.1002/nsg.70028, 2025.