YOLO V5s-based Deep Learning Approach for Concrete Cracks Detection

School of Software, Jiangxi Normal University, Nanchang 330027, China

^* Corresponding author. Email: yzhen_zane@163.com

Abstract

Complex environmental conditions can lead to a variety of cracks in concrete engineering structures, and if these cracks are not promptly investigated and repaired, it is likely to lead to serious engineering accidents. Most of the traditional crack detection method is by manual exclusion, which overly relies on the knowledge and experience of inspectors, and different inspectors have different definitions of crack detection standards, so it lacks a certain objectivity in quantitative analysis, and the efficiency of manual detection will gradually decrease as the workload rises. In recent years, deep learning networks have made many developments in the field of computer vision by their strong feature extraction ability and autonomous learning capability. The main objective of this paper is to detect crack information in crack images using YOLO V5s-based deep learning algorithm. Considering the complexity of the crack image background, the author adopted the threshold segmentation method based on the Otsu maximum inter-class variance to achieve the purpose of removing the background noise from crack images by constructing a connected domain for grayscale change points so as to fuse the noise points with the background. After that, the author used the YOLO V5s model to train and test the 3500 manually labeled crack images, and adopted the K-Means method to calculate the optimal initial anchor box size and pass it to the model for training, so as to improve the model’s detection of cracks. The evaluation index of the model after these two optimization methods was 84.37% for average precision (AP), 76.01% for average recall (AR), and 79.97% for average F1-score.