基于计算机视觉的水火弯板线位移测量系统

详细介绍了研制开发的基于计算机视觉的水火弯板线位移测量系统的主要组成与工作原理 ,该系统的成功应用 ,对研究水火弯板成形加工规律、实现水火弯板的机械化及自动化提供了支持

The Linear Deformation Measuring System of Line Heating in Shipbuilding Based on Computer Vision

Line heating is a main processing method of shell plate with two-direction curvatures in shipbuild-ing.As an important parameter of shell plate forming theory,the linear deformation is difficult to measure accurately.As a new and non-contact measuring method,computer vision measurement could be used to solve this problem.The linear deformation measuring system of line heating in ship-building based on computer vision is presented in this paper,including its main compositions and its working principle.It consists of a gas pressure gun for marking point on the plate and vision-measur-ing device.The vision-measuring device is composed of two CCD(charge coupled device)cameras,two lenses,an image acquisition card,a calibration target block,and a bracket.It works on triangu-lation principle.First,the calibration of binocular stereo cameras should be done.Using the Redial Alignment Constraint method published by Tsai,the exterior and interior orientation can be deter-mined.They are the rotation matrix(for exterior parameters)and camera constant,principle point,lens distortion coefficients scale factors(for interior parameters).For this purpose,a target object for calibration is used,where there are30circle deep holes on the same plane.Comparing the circle cen-ter points with the ellipse center point on image plate,the relation between the object point and image point can be established.Second,by means of acquiring the two images before and after the line heat-ing process,extracting the center feature of marking point through image processing,and matching the center points of marking circle,the system can get the3D coordinate(x,y,z)of the marking points.Then the distance between two points can be calculated.This system has been used success-fully in measuring the linear deformation for the research on line heating shell plate in shipbuilding.It provides a useful measuring method for linear deformation of line heating,and will be helpful for re-search and automation of line heating of ship shell plate processing.