Research On Reconstruction And Mosaic Algorithms For Large-range Surface Measurement With White Light Interference

With the development of ultra-precision machining technology,the requirement of surface contour detection is getting higher and higher.When measuring the contour of precise components such as micro-electromechanical system and micro-lens array,not only the measurement accuracy is required,but also the measurement range is large.Vertical scanning white light interferometry can meet the requirement of high precision profile measurement,but the measurement range of this method is small.Aiming at the problem that the measurement range of white light interferometric scanning method is insufficient,this paper mainly carries out the following research work:1.The influence of noise,sampling step and coherence length on the reconstruction algorithm of three-dimensional surface topography is studied.For the problem of error in Stoilov reconstruction algorithm,an improved reconstruction algorithm is proposed.The method compensates the modulation of white light interference signal and realizes the correction of interference signal.The simulation results show that the improved algorithm can effectively improve the reconstruction accuracy of surface topography.2.Aiming at the splicing problem of large-scale measurement of surface topography,the principle of local feature invariance is studied,and the scale space theory is applied to extract feature points of surface topography.The principle of feature point detection and location is analyzed,and the algorithm of feature point matching and three-dimensional data fusion is studied.The simulation test and mosaic experiment results show that the three-dimensional surface topography mosaic algorithm can effectively realize the mosaic of surface topography.3.Based on the development environment of Visual Studio 2013,a three-dimensional surface topography mosaic software system is designed.The system uses modular design to realize the functions of image acquisition,surface reconstruction,data mosaic,motion control,data analysis and evaluation in the process of three-dimensional surface topography mosaic.4.The surface topography stitching experiment was carried out by using the self-developed three-dimensional surface topography stitching software system.The experimental results show that the horizontal stitching accuracy of the three-dimensional surface topography reaches 0.85 um and the longitudinal stitching accuracy reaches 0.005 um.