Non-Destructive Testing of Rebars in Concrete

Ground penetrating radar (GPR) technology is widely used in the detection and positioning of rebars in concrete, and the distribution of rebars is the key to the quality of structures. At present, the positioning of rebars by GPR depends on the hyperbola fitting after threshold segmentation of B-SCAN. In the case of complex B-SCAN, the existing methods have poor positioning effect on the apex of the hyperbola. At the same time, it cannot meet the requirements for real-time positioning of rebars at the scene.This paper proposes a CUDS-based (Column Up and Down Scan) location method for the vertex of the hyperbola formed by the reabr. By detecting the ROI at the top of the hyperbola formed by the rebar, the symmetry axis of the hyperbola is restricted to corresponding to the wave interval for the vertex of A-SCAN. Then use CUDS to realize the precise positioning of the vertex position of the hyperbola. In order to be able to apply on the mobile terminal with poor computing resources, the lightweight processing of pruning and knowledge distillation is performed on the ROI detection model. This paper combines the detection method of rebar and deploys it on the mobile terminal. In the actual detection of the physical model, the positioning accuracy of the rebar reaches 1.6mm, which is higher than the existing method C3, which verifies the effectiveness of the results of this paper.