The effect of noise on the estimation of rebar radius by inversion of GPR scan data
Ground Penetrating Radar (GPR) is largely used nowadays in civil engineering applications as an effective technique of structural monitoring. This paper describes a method using radargram acquired by the GPR for estimating the radius of a steel rebar buried in a concrete massif, which is assumed to be homogeneous and isotopic. Considering the forward problem under B-scan procedure, a closed form mathematical formula was derived for the hyperbola trace appearing as the diffraction pattern provided by a circular steel bar. This equation relates the observed hyperbola parameters in the obtained radargram to the characteristics of the object and those of the host medium where the object is buried. The inverse problem was solved in two steps. Using the extracted raw data in terms of the hyperbola characteristics and Hough transform, the coordinates of the peak hyperbola are identified. Then the wave speed, the rebar radius as well as the coordinates of the rebar centre are estimated by a curve fitting procedur...