Ellipse-inscribed line-element migration, ELM: a nonparametric object-periphery reconstruction method with multi-static GPR

A synthetic aperture method for multi-static GPR was proposed: it enables a nonparametric reconstruction of upper surface periphery in the vertical section of buried objects by migrating line-elements. The line-elements are estimated by the following reflection principle. Let's assume two TX/RX antennas with different TX/RX distances: in this paper, one pair was assumed to be a monostatic antenna system, and the other, a bistatic antenna system. Then, the RX antenna of the two TX/RX antenna pairs can receive EM waves having reflected at “identical” object surface segments because each of the two TX/RX antenna pairs geometrically satisfy a mirror reflection condition at the object surface segments. Then, the surface segments shall be on a circle and an ellipse that satisfy a time-of-flight to primary wavefronts in two B-scan reflection images by monostatic and bi-static. Therefore, by exploring the minimal distance point between a circle and an ellipse, object surface segments can be estimated. The potential for practical use was confirmed through a field test using a flat plate, a roof-shaped plate and a pipe.