3D Fast Measurement System Based On Line-Laser Rotation Scanning

People's surrounding world is three-dimensional,and three-dimensional detection technology has been applied to many scenes,such as defect detection,mold manufacturing,medical diagnosis,cultural relic reconstruction and so on.Three dimensional detection methods based on optics include coded structured light method,binocular ranging method,phase method,time-of-flight method,laser scanning method and so on.Laser triangulation is widely used because of its low cost,high speed and high precision.Although there are many researches on laser triangulation,there are still some problems to be solved.At present,the laser triangulation measurement system needs to put the scanning device or the measured object on the translation slide rail,and control the relative movement of the object and the scanning device to obtain the three-dimensional information of the object.The problems of this method are:(1)the equipment is bulky and needs large movement space;(2)large mechanical jitter error will beintroduced in the process of linear slip;(3)the moving device is inconvenient which leads to slow measurement speed.In view of the above defects,this paper proposes the scanning mode of line laser rotating around the axis,which has faster detection speed,simpler mechanical control and more stable and reliable results than the traditional translation mode.In this paper,the theoretical model of linear laser rotary scanning measurement is deduced,and the software and hardware system is built to solve some engineering problems in the measurement process.Finally,the experiment proves that the method can achieve good results in scanning the overall contour of the object.The specific work of this paper is as follows:(1)The principle of line laser 3D measurement is studied,including camera imaging model,camera and datum calibration method,laser triangulation method and so on.On the basis of these methods,this paper puts forward a measurement method of laser fast scanning,puts forward the oblique incidence laser rotary scanning model and the calibration method of the model system parameters,makes a theoretical derivation of the proposed model and calibration method,and gives the calculation formula.(2)Based on the measurement model of oblique incidence laser rotary scanning,a set of three-dimensional detection system is built,and the hardware system and software algorithm module are introduced in detail.The scanning speed of the system based on this paper is 376.99 times faster than that of the traditional translation scanning system;when the working distance between the camera and the laser is 500mm and the horizontal distance between them is 300mm,the sensitivity of the system can reach 238 ?m;in addition,the repetition error of the system is 0.048mm and the average height measurement error is 0.13mm.(3)A complete system algorithm flow is proposed,involving image processing and 3D reconstruction.Image processing includes noise reduction and filtering,laser stripe region extraction and laser stripe center point extraction.In the part of 3D reconstruction,the Delaunay based triangular mesh generation method and Poisson equation surface reconstruction method are introduced,and the reconstruction results of the two methods are compared.