High-precision Micro-surface Measurement And Reconstruction Base On Laser Scanning

With the rapid development of science and technology and production process,micro-miniaturization technology has become the frontier field of many disciplines after many years of research and development,and has a broad application prospect in precision machinery,electronics,optics and other fields.Because of the increasing use of micro-machinery,The accurate detection of geometric dimensions and defects of micro parts is the key to ensure the quality of micro products.It is of great significance to study the measurement technology of tiny objects.It is precisely because of the small size of the small parts and its surface is not suitable for contact and other characteristics,the high-precision detection technology has more difficult.In this paper,the single line laser scanning technique based on laser triangulation is analyzed,and the related techniques are studied deeply.The development of the measuring system is completed and the high-precision 3d reconstruction of the measured surface is realized.Based on the principle of laser triangulation and Combined with a single laser source,the mathematical model of the 3d measurement system was established to detect and reconstruct the 3d shape of the micro-surface.In the process of measuring system mathematical model is established in this paper,in order to improve the measure accuracy,in this paper,the factors that affect measuring accuracy were analyzed,The advantages and disadvantages of oblique incidence and vertical incidence are analyzed,analyzes the system structure of the different influence on measurement accuracy,and study the internal camera parameters and light plane equation parameters calibration accuracy and depth of field lens factors influence on the measured results,optimize the structure of system,provide theoretical support to improve accuracy of measurement system.In the process of camera internal parameter calibration,Tsai camera calibration method was combined.First,we solved the camera's main point coordinates according to the method of feature point movement with Halcon calibration plate.Then,solve other camera's internal parameters with Tsai's two-step method.Proposed a simple and feasible scheme for the calibration of the structure parameters of the laser scanning system.Structural parameters of the measuring system are calibrated step by step to achieve the purpose of calibrating the plane equation of light.As we know laser stripe center position precision directly affect the measurement result,in order to improve the measurement efficiency and stripe center positioning accuracy,analyzed the stripe data and the separated image background,The two-dimensional fringe image is converted into one-dimensional data.Gaussian convolution summation method is used to determine the stripe center.Matlab simulation shows that gaussian noise with variance less than 0.4 is added,the positioning accuracy of RMS is less than 0.2 pixel,can meet the needs of the measurement.After the measurement of 5mm standard block,the system distance positioning accuracy can reach 40?m,X,Y direction positioning accuracy is better than 25?m,The measuring system has high precisionThrough multiple scans of objects,We were able to get multiple sets of three-dimensional point cloud data.Invalid points are removed by filtering method.Multiple sets of data are converted to the same coordinate system,point cloud data splicing and other operations are realized by data fusion,completed high-precision three-dimensional reconstruction of the surface.