Study On The System Of Visual Identification In Postal Sorting Line

Package delivery holds a large proportion in the express company’s business. Inorder to improve the automation level of postal sorting, in this paper, we design apackage sorting system based on3d laser scanner. This system consists of detectdevice,3d laser scanner, industrial robots, computer and control units. The systemuses the point cloud processing technique to obtain the geometrical information andspatial position of target object. This paper focuses on the algorithm of organizatingpoint cloud, removing the discrete points, initial registration based on the curvatureand ICP registration based on kdtree. After two times of registration, we canaccurately calculate the transformational relations between the two machinecoordinate system of3d scanner, making the position and size calculated online meetthe required of precision, which improves the sorting speed. This system puts thebarcode scanning techniques,3d scanner technology and robot technology togethereffectively, which improves the automation level of sorting line, reduces the spaceusage of sorting line and avoids the damage to the express mail. It is the first time for3d laser scanner to be used in postal sorting line. So the research on the system isinnovative and exploring.In order to improve the automation level of sorting line, we choose theinformation of the package’s pace geometry information as the research object. Themain research works of this thesis are carried out as follows:Firstly, according to the actual working environment of the sorting line, wedesign the structure of the system to collect points cloud. The main problem is tocalculate the coordinate transformation between the3d laser scanner’s machinecoordinate system, the coordinate transformation between the machine coordinatesystem of3d laser scanner and manipulator, and position of the complete model.Secondly, in order to make the two point sets collected joining together into acomplete model, we need to research the point cloud’s pretreatment algorithm. Thispaper’s main research works are the algorithms of establishing point’s neighborhoods,denoising, calculating points’ geometric features, the initial registration based on thecurvature, and ICP registration based on kdtree.Then, we calculate the target’s posture and geometry size by a algorithm ofminimum enclosing rectangle. Regular grid method is used to calculate the target’scenter of gravity.Finally, applied C++and MATLAB, a system of postal sorting line based on3dlaser scanner is designed and developed. Also the system was proved to be effective. The system can improve the degree of automation, which can reduce themanpower cost, and improve the efficiency of sorting.