超塑性自由胀形实验中准确测量胀形件轮廓曲面以及曲面上各点的变形是建立超塑性自由胀形解析理论的重要基础. 本工作依据自由胀形件轮廓为轴对称旋转曲面这一重要特征, 将曲面测量问题转化为曲面上特征点的测量, 采用双目立体视觉系统测量特征点的三维坐标, 并进行曲线拟合以确定其轮廓曲面, 计算几何参数, 通过分析轮廓曲面上特征点位置变化以及两相邻特征点之间间距的变化来测量应变. 介绍了双目立体视觉系统的组成和测量方法, 以及系统模型、标定方法、消除高温影响和图像处理等关键环节, 给出了胀形件几何参数和变形测量的方法, 进行了测量实验.

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.