Research On The Three-dimensional Measurement System Of Small Field Fringe Projection Phase Matching

High precision three-dimensional measurement is one of the main research directions on industrial measurement field.It plays an important role in industrial manufacture and automatic detection.People pay more and more attention to the high-precision three-dimensional measurement of small objects.In this paper,for the three-dimensional measurement of small objects,by combining the fringe projection phase matching technology with binocular stereo vision technology,a small field fringe projection phase matching three-dimensional measurement system is designed.According to the requirements of the subject,the measuring system can measure small hemispheres,and calculate its height and radius through the analysis of three-dimensional point cloud data.The main contents of this paper are as follows:1.A set of "dual camera projector" small field fringe projection phase matching three-dimensional measurement system is designed.According to the requirements of field size and measurement speed accuracy,choose the required camera,projector and other reasonably devices.At the same time,the computer software is designed.2.Combined with the characteristics of phase extraction of fringe image,a stereo matching method based on the mixed constraint of polar constraint and fringe order is proposed,and a window template is designed.The initial matching point is determined by phase information and template matching,and use the initial matching point and the nearby point to get the subpixel matching.3.Do the research on the algorithms of point cloud data.The point cloud data is sampled by voxel grid method,and the noise point cloud is removed by multi filter algorithm.By analyzing the features of the point cloud data of the small hemisphere and comparing different segmentation and recognition algorithms,an improved RANSAC algorithm is proposed to extract the features of the hemispheres height and radius.In this paper,a small field of view 3D measurement system is built,which can obtain the 3D point cloud data of the measured object and calculate the height and radius parameters.The experiments show that the standard deviation of single measurement is no more than 5 ? m for the hemisphere with a radius of 5 mm.