Research On Measurement Methods For Large-scale Flat Parts

Vision measurement technology has been developed rapidly and widely used in recent years.It has gradually become an important part of the modern industrial production.Monocular vision measurement technology has been widely studied because of its simple structure,low cost,easy to implement and so on.On the basis of analyzing and studying the existing monocular vision measurement technology,the large size planar parts measuring system was designed and a measuring method for large size planar parts was proposed in this paper.Firstly,the intrinsic parameters and extrinsic parameters were obtained by camera calibration with distortion model.Secondly,upper and lower edge points distinguishing method based on direction angle difference was proposed by analyzing the imaging features of large size planar parts,and a method to obtain the complete upper edge was proposed.Finally,upper edges were converted to the measurement plane by the method of similar triangle,and the physical size of the measured object was solved by using the intrinsic and extrinsic parameters of the camera.Experiments were performed in order to verify the feasibility and accuracy of this method,results showed that the absolute accuracy of the lmm-10mm thickness,500mm long,500mm wide parts and 1mm thickness,1100mm long,300mm wide part in the range of 1200mm×800mm was up to 0.08mm,the relative accuracy of above parts was up to 0.05%.It can satisfy the measurement precision requirements of planar parts processing.