Research On The Method Of Defect Detection Of Steel Plate Surface Based On Moiré Projection

Defect detection plays a vital role in industrial quality control,and the quality of steel plates,an essential raw material for industrial production,has a direct impact on industrial development,so it is important to control their surface quality.In this context,this paper designs a non-contact measurement method to detect defects on steel plates,which can detect defects on the surface of the plate and determine the size and location of the defects.The application of this method to the inspection of defects on the surface of steel plates reduces labor costs and greatly improves the efficiency and quality of the inspection.A CCD camera and a digital projector are adopted to capture the defused images of the steel plate surface defects,the elimination of phase errors by polynomial methods and rotational correction is an important step in the preprocessing.To obtain the 3D shape of the object,The Fourier transform profilometry（FTP）is applied;The ideal filter and Hanning bandpass filter are designed to obtain the phase map.By Comparison,the Hanning window is selected,followed by the acquisition of the principal phase of an image;the phase true phase map is obtained by the branch-cut method.The 3D reconstruction of the object surface is completed by obtaining ?φ,and then the defects and location information of the object surface are detected by image segmentation.Finally,an Experimental platform of a defect detection system based on moiré projection is built,which can detect defects on the surface of steel plates.The experiments show that the method can detect defects with a minimum size of0.3mm and a depth of 0.2mm,and has good stability.