Research on Locating Tunnel-Lining Defects Using Fast Synthetic Aperture Focusing Imaging Based on GPR

Abstract

This paper proposes a method based on image processing algorithms for ground penetrating radar (GPR) to locate hidden defects in tunnel linings. Firstly, the fast synthetic aperture focusing imaging (Fast-SAFI) algorithm is used to accurately identify the morphology of tunnel-lining defects. Secondly, an iterative algorithm is used to determine the connected regions on the binary image, exclude background noise interference, and locate the centroid and vertices of the correct target connected regions to achieve the positioning of the depth of tunnel-lining defects. To verify the feasibility of the proposed positioning algorithm, a verification experiment was conducted on the experimental wall of the China Academy of Railway Sciences. The experimental results show that the proposed positioning algorithm is reliable and rapid for identifying and locating the morphology and depth of tunnel-lining defects.