Research On 3D Shape Measurement Of Honeycomb Structure Based On Machine Vision

The honeycomb structure has been paid much attention in the field of aviation because of its advantages of light weight,high strength,high bending rigidity and strength.However,it is hard and inefficient to gain exact intersection by the traditional CMM(Coordinate Measuring Machine)which needs a lot of manual interaction due to the special structure of the honeycomb.3D digital point cloud measurement technology developed in recent years is also not good for the shape of honeycomb structure measurement.Therefore,the three-dimensional shape measurement technology of honeycomb structure,which is based on stereo vision technology,digital image processing technology and related computer vision theory,is studied in this paper.The main research contents and innovative points are summarized as follow:1.Honeycomb grid image preprocessing technology is studied.A straight line segment detection(LSD)is proposed to obtain single honeycomb mesh boundary information by calculating the pixel area and the evaluation of the linear region of rectangular bounding box angle to determine whether the target line,so as to realize the extraction of single line edge of the grid.2.Completing the establishment of the topological relationship of grid area based on the growth method of grid.Grid nodes achieve the establishment of topological relationship based on the topology relation of grid area.Finally,the precise intersection of the grid intersection is achieved by template method.3.A stereo vision measurement system is built.The matching of the grid intersection points in the stereo image is achieved by using principle of epipolar geometry.Finally,according to the matching image coordinates and camera calibration results,the 3D reconstruction of honeycomb structure is completed,and the validity of the method is verified by objects experiments.