Warpage Measurements of Metal Plate Based on Machine Vision

Aiming at the warping problem caused by the temperature difference between the upper and lower surfaces of the metal plate during heat treatment, a metal warping detection system based on machine vision is designed. The system extracts the feature information of calibration plate in the image as the dimension reference of metal warping detection. Then, the ROI(Region of Interest) of metal warping is selected for Blob analysis to obtain the metal warping area. The height of the minimum circumscribed rectangle is calculated as the maximum warping height of the metal, and the position of the metal when the maximum warping occurs is displayed, the height divided by the width of the minimum circumscribed rectangle is the warpage of the metal plate. The experimental results show that the system can detect the metal warping and display the position in real time, and has the advantages of fast operation speed and small error. The measurement accuracy can reach 0.1mm. It can provide data basis for the research and analysis of the cause of metal warping.