Research On Vision Measurement Of The Thermal And Large-size Forging Based On Laser Scanning And Data Registration

With the rapid development of modern industrial technology,the production of large-size forging has become increasingly important.The size of large-size forging,is an important indicator timely detected in forging production.for a long time,the dimensions measured by the method of artificial visual in the forging process of high temperature forging resulted forging size generally is more than the specified value a larger margin (forgings average loss amount of 15%).The purpose of this research is the use of binocular stereo vision technology to build non-contact vision measurement system of large-size forgings thermal.Considerd the thermal characteristics,using the word line of green laser scanner motor way construct characteristics point in the surface of measured forging to solve the problem of stereo vision matching.Considerd the huge axial size characteristics,using the data splicing method to solve the problem of address the multi-station multi-stage data on the unitary coordinates.After the analysis of various camera calibration method,based on the use of Zhang plane calibration method,from a single camera calibration extended to three-dimensional vision system calibration,realized this high accuracy calibration of the vision measurement system in the matlab.In image processing,using the digital filter technology to elimination of the impact of light interference;using the median filtering technology to effectively eliminate the impact of random noise impact;using the sub-linear gray transformation to effectively improve the image quality;using the distortion of the amendment to eliminate the cause of the distortion of the image error;using canny edge detection to extract the edge of the left or right end line;using fixed thresholding, morphological erosion,thinning processing to extract the features central skeleton of cross-section beam;using adaptive thresholding,center extraction based on recursive binary image connected domain to extract splice signs point;used polar correction technology to eliminate the two image parallax of vertical direction.produced activity splicing block;and used svd decomposition to splice data between the measurement sites.After the in-depth theoretical study , constructed the thermal and large forgings vision measurement system based on laser scanning and data registration,Writed the measurement software,and achieved cylinder-type hot forging physical measurements in two measurements sites.