Research On System Detection Of Wheel Tread Defects

With the development of the railway, defect inspection of rails becomes more and more important to ensure the safety. The problem that how to measure the fault of the tread profile is concerned all along and perpetual studied and improved. That is because the irregularities of tread profile are the key factor of influencing the safety, stabilization and economy of running.The paper is composed of a hardware part and a software part.The first part mainly designs the hardware frame of the system using for reference universal the model of machine vision system. It aims at the system precision's demand and chooses the right components and computers each component' parameters.The second part is mainly about image processing. According to the surface defect image's traits and using digital image processing it calibrates the distorted images and abstracts the defects from the tread images. The key steps include pretreatment, tread location determination, edge detection, edge link, defect orientation. Under-mentioned arithmetic has a great influence on inspecting and analyzing defects exactly.1. In order to avoid the disturbance of the wheel, tread region is oriented by using vertical edge detection. The operation can intensify rail's borderline and cut it down by projection.2. The edge of the defect is abnormity. In order to abstract the defect with high precision, canny method is applied to carry on edge detection.3. Improved edge growing arithmetic is advanced to link discontinuous edge, which increases connectedness.4. According to the calibration stencil-plate, we get the size of one pixel; then after Zhang Zhengyou image calibration, we get the tread defect's real size.