“…However, conventional methods for finding tunnel defects, such as visual inspection and acoustic inspection, have low detection efficiencies and high result error. Given the quick advancement of deep learning technologies in the detection of targets, such as damage detection and localization of bridge deck pavement [ 2 ], crack detection in concrete bridges [ 3 , 4 ], steel surface flaw detection [ 5 , 6 ], and wheel defect detection [ 7 ] across a variety of disciplines in society, science, and engineering, deep learning-based tunnel flaw detection has recently gained the attention of both domestic and international academics. For example, Sjölander et al [ 8 ] summarized the research on the application of optical detection technology and autonomous evaluation methods based on machine learning technology in tunnel lining inspection, as well as the research on digital cameras, laser scanning, fiber optic sensors, and other methods; they also proposed issues with traditional tunnel inspection methods, such as their low efficiency.…”