A Time-Delay Calibration Method for Profile Estimation of Two-Layered Rough Surfaces

Abstract

For detection of a two-layered rough surface structure through ground-penetrating radar, the estimation of the profile of each layered rough surface is an important problem to be solved. In modeling and calculating the scattering of two-layered rough surfaces, we found that the profile of the upper rough surface can be observed directly through the figure of the echo from the upper surface. However, the echo of the lower rough surface has a quite different shape from its surface profile, because of the influence of the scattering of the upper rough surface. This is disadvantageous to the estimation and imaging of the profile of the lower rough surface. To solve this problem, a time-delay calibration method is proposed in this paper to be applied to the profile estimation of the lower rough surface in the case of two-layered rough interface detection. By introducing a smooth surface, the expression of time delay is derived to eliminate the influence of the scattering of the upper surface. Applying the derived expression of time delay to the echo data from the lower rough surface, the echo outline of the lower rough surface can be corrected to reflect the surface's profile shape. The calibrated B-scan echo shape shows good agreement with the profile of the lower rough surface. With this method, we can get the profile shape of the lower rough surface quickly and simply by calibrating the echo data directly. This method can be used for fast microwave imaging of two-layered rough surface and for eliminating the interference of scattering from rough surface on the echoes of nearby targets. The purpose of this paper is to solve the problem we have found in our previous work. The work of this paper is an extension of the previous work. INDEX TERMSProfile estimation, time-delay calibration, two-layered rough surface scattering, ground-penetrating radar, echo shape.

Microwave-Based Subsurface Characterization through a Combined Finite Element and Variable Exponent Spaces Technique

“…These classes of approaches, although more computationally expensive, are particularly advantageous when certain geometric configurations and specific soils are present in the domain. In addition, several radar-like techniques [ 37 , 38 , 39 , 40 ] have been recently proposed in this research area to allow soil profiling, so that retrieved soil configuration can be accurately integrated into the electromagnetic model as a priori information [ 41 ]. Finally, hybrid solutions combining analytical and numerical models have also been proposed [ 11 ].…”

Analysis of Imaging Internal Defects in Living Trees on Irregular Contours of Tree Trunks Using Ground-Penetrating Radar

“…Estimating the rough surface contour can eliminate clutter interference from the target, allowing more accurate target identification and imaging. Scattering from rough surfaces with laminar structures has been calculated using the method of Finite Difference Time Domain (FDTD) [19,20]. It was found that the shape of the echo of the upper surface was always the same as the contour of the rough surface, regardless of the change in roughness.…”