Research On Technology Of The Tree Dimensional Targets Based On Binocular Vision

Traditional portable light pen has a light weight,good portability,forming a flexible,simple operation,moderate precision,measurement is not affected by measured surface differences,etc,however,is not suitable for automatic measurement.This paper presents a three-dimensional targets,it based on the traditional portable light pen with three cameras identify measuring surface,realized in the condition of several appearance of workpiece is measured.In the process of measurement,the target is not only can hold measurement,and can be used to drive the three-dimensional targets for automatic measuring machine hand,fast accurate workpiece to be measured for 3 d point coordinates,realize the automation of industrial measurement site online and flexibility.Therefore,in this paper,the measurement of three-dimensional targets key technology,has important theoretical significance and practical value in engineering.In this paper,the main work includes:1 Based on principle and composition of measuring system of three-dimensional target in this paper,a solid target structure of regular tetrahedron was designed;the four sides of target are determined as the measuring surface.Analyzed different algorithms of image matching based on the principle of parallel light binocular distance measurement,compared the different characteristics of the back light reflex landmark and LED point light,and finally choose the marking point types for three-dimensional target is reflection code landmark,and coding principle is given.2Through image preprocessing and connected domain method of three-dimensional target,rectangular or diamond images with the geometry shape is obtained from target surface.By comparing the geometry of the rules of rectangle or rhombus image sizes,choose the three-dimensional targets of measured surface.By defining the roundness method fully extracts the target face image projection ellipse in the landmark,using grey qualitative method to obtain the center of the landmark image coordinates.Center coordinates and using the landmark rules target surface area of the image,to extract the target face image coding region landmark,and presents a coding method for decoding.3 According to the principle of central projection,this paper set up the ideal camera model,derivation corresponding relationship between two-dimensional space coordinates of the images and the corresponding three-dimensional coordinates,increased camera radial distortion and tangential distortion model,modify the camera ideal model to get the camera real imaging model.And using MATLAB software on the calibration of binocular camera.4 This paper designed the coordinate's measurement procedure of coding points based on parallel light binocular vision center,set up the experiment measuring platform of the three-dimensional target.This experiment measured the distance between encoding landmark center of different locations of three-dimensional targets and the camera,through 36 differences of the distance between different position of three-dimensional targets and cameras,analysis and calculation of the system ranging distance is of 20 + /-0.0147 mm.At the same time sub millimeter level at the ranging precision of this system is also concluded,which satisfied the designing requirements.