BINOCULAR STEREO VISION MEASUREMENT RESEARCH FOR SUPERPLASTICFREE BULGING

It is a significant foundation of superplastic free bulging analytic theory to accurately measure the surface profile and the deformation of each point on surface.Based on an important feature of the profile of the free bulging part which can be depicted as axisymmetric rotating surface,in this study,the measurement of the surface was translated into that of the feature points on the part surface,and the three-dimensional coordinates of these points were measured by the binocular stereo vision system for the first time.Then,through curve fitting,contour surface and geometric parameters were determined,and the strain were characterized through analyzing coordinates change of the feature points and distance change between two adjacent points.The setup and the measuring method of the vision system were introduced,as well as several key steps,such as system model,calibration method,elimination of influence of high temperature,and image processing.The methods were proposed for measuring geometric parameters and deformation of bulging part,and the related experiments were performed.