Intelligent system for non-destructive evaluation of historic walls using Ground-Penetrating Radar

This paper presents a novel system for application in evaluation of ashlar masonry walls inspected with Ground Penetrating Radar (GPR). The system includes the following processing of the GPR signal: elimination of the background from the backscattered signals; depth resolution enhancing; automatic gain control for visualization; and automatic generation of B-Scans (radargrams) of the internal state of the wall. Inhomogeneities in the structure of the wall are detected from the B-Scans. Several experiments were made on scale models of historic ashlar masonry walls. Controlled loads with different weights were applied on the walls, and the corresponding B-Scans were obtained. It is demonstrated the capability of the system for the detection of nook and crack flaws, and for characterizing the deformations of the walls under different steps of weight loads.