In order to further improve the identification accuracy, Wang et al. A multi-class support vector machine (SVM) real-time detection system is proposed based on visual saliency. Reference aims at surface damage identification of conveyor belts. , an improved single-scale Retinex (SSR) algorithm is used for image enhancement, and the features-including the area, damage level, and squareness-are extracted by the greyscale image. More and more defect detection methods based on machine vision are proposed in non-contact detection methods. Therefore, the non-contact defect detection method has been gradually developed. However, the contact detection method would gradually reduce the detection accuracy due to contact wear. The contact detection methods usually add an extra mechanical component, embed an induction coil or a radio frequency identification device into the conveyor belt for tear detection. #RISK 7.5 INDUSTRIAL CRACK CRACK#The detection results of different sizes of mini-crack show that the laser excited thermography has high damage sensitivity (1 mm diameter mini-crack detection), high accuracy (96%), lower power consumption (15 W laser excitation), and high SNR (signal-to-noise ratio).Īt present, there are generally two methods of conveyor belt crack detection: contact detection and non-contact detection. The experimental results show that the mini-cracks with length of 50–140 mm, width of 1–10 mm, and depth of 5 mm can be successfully detected, and the detection accuracy could reach 96%. After that, the threshold segmentation and Hough transform algorithm are used to determine the size of the mini-crack. To reveal the features of mini-crack, the power function image enhancement algorithm is proposed. It could transform multiple sequential thermal images into a single thermal image according to the frame difference method, so that the infrared thermal response of the mini-crack over time could be recorded quickly. Then, an algorithm for extracting and fusing the features of mini-crack belt’s thermal images is firstly proposed by using time sequence analysis. A laser beam is applied to generate a heat wave on the belt surface, so the corresponding thermal images can be recorded by an infrared camera. In order to detect mini-cracks in a timely manner, before the occurrence of large tears, a new mini-crack detection method for conveyor belts based on laser excited thermography is proposed. The lumpy material rubbing against a belt with mini-cracks will lead to detrimental tears on the belt while the conveyor works at high speeds. For a belt conveyor, a belt with mini-cracks influences the safety of the operation of the belt conveyor devices significantly.
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