Research On Multi Parameter Measurement Technology Of Crack Plane Based On Computer Vision

Crack is an important index to measure the structural health of structures.The traditional method of obtaining crack parameters has some disadvantages,such as high measurement cost,low efficiency,poor accuracy and so on.This paper develops a crack measurement technology based on double identification,which converts the crack measurement into the measurement of identification,and obtains the change of crack parameters by measuring the relative displacement of identification.Based on computer vision technology,a high-precision crack parameter measurement technology is constructed.This technology collects images from smart phones,cameras and other devices,establishes a coordinate system,calculates the relative coordinates,and obtains the measurement data of crack parameters based on the constant cross ratio.The main research results of this paper are as follows:(1)Taking the two-dimensional code as the identification,a positioning point detection algorithm based on the two-dimensional code is proposed.The algorithm uses the location pattern of two-dimensional code to locate multiple location points on the crack plane,and establishes the order of location points,so as to provide basic calculation parameters for the quantification of crack parameters.(2)An improved vanishing point detection algorithm based on Hough transform is proposed to detect the vanishing points on the identification plane.Through the image features of two-dimensional code,the algorithm first extracts and groups the lines,then optimizes and merges the lines,and finally calculates the vanishing points.(3)Define crack parameters and A crack parameter measurement algorithm based on cross ratio is proposed.For plane cracks,use the vanishing point and locating point to establish the cross ratio calculation scheme in the identification plane to realize the calculation of crack parameters.For non plane cracks,a point projection method based on double images is proposed.All points outside the plane should be on the plane,and then calculated according to the plane crack method.(4)An indoor test platform is built to simulate various changes of cracks.Through the simulation test,the stability and accuracy of the algorithm in different scenarios are verified,and the periodic changes of cracks are effectively obtained through field application.