Design And Application Of 3D Imaging Detection System For Cryogenic Insulation Cylinder

With the development of computer vision technology,three dimensional detection imaging technology has been widely used due to its advantages of non-contact and non-destructive.According to the research tendency of the vision coordinate measurement technology and three-dimensional detection technology,in this thesis a three dimensional imaging detection system is designed for cryogenic insulated cylinders,which are base on the research background of low-temperature insulation cylinder detection project in a city and take the appearance defect detection of cryogenic insulation cylinder as the research object.In addition to that,the method of three dimensional imaging detection be come out for the appearance of cryogenic insulation cylinder.The main research contents as below:Firstly,the three-dimensional detection system is calibrated.Aiming at the existing problems of scanning machine structure,the single line and line structured light is calibrated by using checkerboard pattern,binocular calibration using concentric circles,the calibration accuracy is improved.Secondly,the Hessian matrix method is used to extract the line structured light stripe center.In the algorithm,Canny operator boundary segmentation and sine function triangle fitting algorithm are added.Canny operator boundary segmentation makes the Hessian matrix only convolution operation for the segmentation region,which speed up the extraction.Trigonometric function fitting method,the problem that the structure light of large size low temperature insulation cylinder is no longer in line with the normal distribution and the light stripe is broken due to the surface reflection or the edge curvature is too large.Lastly,a new algorithm be presented by combining RANSAC(Random Sampling Consistency Algorithm)and cylindrical fitting algorithm,which solves the influence of noise and precision or the image splicing occurs when splicing is not accurate or the problem of dislocation.Finally the three-dimensional imaging detection of cryogenic insulated cylinders be realized.In this thesis,a three dimensional imaging detection system is designed for cryogenic insulated cylinders,which improve the detection efficiency and present a favorable prospect of development.