Pipeline Three-dimensional Vision Measurement And Structural Feature Parameter Recognition Based On Laser Pointer Imaging Points

As an extension of ground construction,urban underground construction provides a new way to solve the rational allocation of land resources,optimize the overall layout of cities and rationalize urban construction.Using robot in the underground pipeline can effectively eliminate the hidden danger of safety,less the incidence of accidents.Among them,the tracking problem of pipeline detection robot is very important,but the insufficient three-dimensional data inside the pipeline and the imperfection of the reconstruction method make the robot cannot make reasonable pre-judgment in the pipeline,and the accuracy and efficiency of the detection are low.In order to provide reliable motion navigation information for the robot in the pipeline and realize the construction of the pipeline environment map information,it is necessary to measure the three-dimensional spatial point cloud data of the inner wall of the pipeline,and then extract the effective structural parameter information inside the pipeline by the algorithm by the obtained data.Therefore,in view of the above two aspects,the research ideas of this paper are put forward,the main research contents are as follows:(a)Aiming at the special environment of gas pipeline,a three-dimensional measuring device of pipeline based on laser Pen Imaging point is designed and implemented,which can realize the measurement and acquisition of three-dimensional coordinates of inner surface point of pipeline.(b)According to the designed measuring device,a preliminary algorithm of three-dimensional vision measurement is proposed.Moreover,through camera calibration and structural parameter calibration experiments,the three-dimensional world coordinates of the target point are measured.Compared with the real value,the possible causes of the error are found.To further improve the algorithm,we designed the optimization algorithm of three-dimensional vision measurement.Through the experiment and the programming design of the algorithm,the three-dimensional coordinates of the target points which are closer to the real value are obtained,and the accuracy of the improved three-dimensional vision measurement algorithm is verified.(c)According to the measuring device and the optimization algorithm of three-dimensional vision measurement,the three-dimensional spatial point cloud data of the inner wall of the pipeline in front of the robot motion is determined,and the coordinate system conversion algorithm is designed to solve the optimal rotational translation matrix between the robot coordinate system and the pipeline coordinate system.(d)The types of gas pipelines divided into different geometrical structures,and according to the structural characteristic models of each pipeline,the surface equation of pipelines are established,and the corresponding structural feature parameter recognition algorithms are designed respectively based on the structural parameters that need to be identified in the pipeline equation.The algorithm is programmed and the experimental results of two types of pipeline structural feature parameters are obtained,and then the structural characteristic parameters of the pipeline are identified.In this paper,a complete solution of pipeline robot from obtaining three-dimensional point data from inner surface of pipeline to identification and reconstruction of pipeline structure parameters is put forward systematically.It is eager to know the structure parameters and direction of the front pipeline in advance when the robot is working,and provides the conditions for constructing the map of underground pipe network with detailed parameters.