Research on preprocessing method based on cylindrical image restoration of steel pipe

Machine vision is more and more widely used in industrial inspection. In order to improve the industrial production of steel pipes, machine vision is used to replace manual inspection of steel pipe surface defects. Because the surface of the steel pipe is cylindrical, there are different degrees of deformation and information loss in the edge parts on both sides of the image when capturing the steel pipe surface image. Aiming at the deformation and distortion problems of the edge of the steel pipe image, a mathematical model is established and calculated. According to the principle of cylindrical projection, this paper deduces the expression of cylindrical orthographic projection, and puts forward a restoration algorithm of cylindrical back projection, which realizes the cylindrical expansion of steel pipe image, and solves the problems of defect shape distortion caused by the deformation of the edges on both sides of the image and the difficulty of defect detection. The results show that this method is effective and lays a foundation for steel pipe detection.