Surface defect tracing method based on cold-rolled product

The invention provides a cold-rolled product surface defect tracing method, which comprises the following units: a hot rolling unit, an acid rolling unit, a cold rolling unit, a continuous annealing unit and an on-line visual inspection machine, the on-line visual inspection machine obtains a steel surface defect image and determines the condition of the surface defect according to the steel surface defect image; relates to the technical field of metal surface detection, an on-line visual inspection machine obtains steel surface defect images and determines the condition of the surface defects according to the steel surface defect images, the method not only compares the morphology change of each defect on the surface of a cold-rolled product in different processes, but also provides reliable test data for tracing of the surface defects; meanwhile, the influence degree of the surface defects of different procedures on the surface quality of the cold-rolled sheet is evaluated, the surface defect judgment stand