Three-dimensional Measurement Of Small Curved Surfaces Based On Line Structured Light

In the field of m easurement,the trad itional measurement method has some problems,such as the need to contact with the measured object,the complex surface is difficult to be measured accurately,the measurement process is affected by human factors and the use of empirical formula,which leads to the measurement work cannot meet the requirements of high accuracy.The measurement technology which based on the optical,digital im age and computer vision can quickly and accurately obtain the three-dimensional information of objects.Therefore,this research h as important theoretical significance and practical value.Line structured light 3D m easurement is a three-d imensional measurement technique based on vertical incidence lase r triangulation,which is one of the m ain methods to obtain the 3D data of the m easured object.With the rapid speed,high precision and non-contact etc.T o deeply research the key technology of 3D surface measurement based on digital image processing and machine vision by the method of combining theoretical analysis with experimental research.Contents of this paper are mainly consisted of the following five aspects:(1)This paper introdu ces the bac kground and significan ce of 3D surface measurement based on line structured light.Re search status of structured light 3D measurement algorithm and equ ipment at home and abroad,this paper gives the overall research content and the chapter arrangement.(2)Built the structure of this measuring system,which is com posed by a line laser,an industrial camera,a translational experiment platform and a compute.In the measuring system,the line structured light vertically projecting onto the surface of the measured object.The position relationship between camera and the line structured light is relatively fixed.The surface of the measured object is scanned by the constant moving experimental platform,to reconstruct the 3D model of the measured object by analyzing and processing the deformation image of the measured object(3)In order to improve the calibration accuracy of system parameters and obtain the parameters of the measuring system,studying the geometry model of cameras and methods.to calibrate cameras.The calibration method of initial parameters with two iterations based on HALCON is pos ed,the calibration process is sim ple and easy to realize,and the calibration pr ecision is higher than the original calibration method.The parameters of the laser plane position and the moving direction of the experiment platform are obtained according to the in trinsic and extrinsic parameters of camera.Provide the basis for the subsequent three-dimensional measurement.(4)In order to im prove the extraction speed of the light stripe im age.A comprehensive analysis of the existing methods for the extraction of the center points of the f ringe image.The exis ting Steger algorithm is f urther improved through combining with the image processing technology and Gauss kernel function,and Put forward a faster light stripe center extraction algorithm.(5).In order to verify the validity of the 3D measurement system,three kinds of objects which have different surface complexity are selected to carry out comparative experiments.In addition,to display the measurement results directly,the surface of 3 kinds of measured obj ects is reconstructed.The different factors that af fect the measurement are analyzed.