Research On High Precision Wheel And Rail 3D Reconstruction Method Based On Multi-Sensor

The non-contact detection technology based on computer vision has developed rapidly in recent years,especially the high-precision three-dimensional reconstruction method based on structured light.Because of its non-contact,fast speed,high precision and strong security,it has been widely used in the industrial field.The three-dimensional reconstruction of the wheel rail contact area under the operation state is conducive to reveal the relationship between the wheel and rail contact attitude and the disease.It has important application value for monitoring the train operation state and ensuring the safe operation of the railway It has important application value for monitoring the train operation state and ensuring the safe operation of the railway Due to the complex space of the lower part of the train bogie and the large distance between wheel sets,the deployment,calibration and data processing of multi-sensor are very difficult.Therefore,high-precision wheel and rail three-dimensional reconstruction is a very challenging task.This paper studies the high-precision wheel and rail 3D reconstruction method in complex deployment space,analyzes the wheel and rail structure through a large number of investigations,and proposes a wheel and rail 3D reconstruction method based on multisensor line surface structured light mixing.The optical connection area of the wheel track is reconstructed by the method of reconstructing the optical contact area of the wheel track.In this paper,the global multi-sensor calibration method of non overlapping field of view and the line structured light 3D reconstruction technology are deeply studied and practiced,and a line surface structured light hybrid wheel and rail 3D reconstruction system in complex deployment space is designed and implemented.(1)Aiming at the problem that there is no overlapping field of view between multiple groups of sensors in global system calibration and it is difficult to use binocular camera calibration method,a flexible and stable combined large-scale target is designed,and a camera calibration method based on this target is proposed.In this method,only one calibration plate image is taken by binocular camera,and the pose relationship of non overlapping field camera can be calculated.At the same time,a nonlinear pose optimization method based on LM algorithm is proposed.The experimental results show that this method can achieve camera calibration without overlapping field of view,the re projection error is less than 0.5 pixel,and the measurement error is less than 0.6 mm.(2)Aiming at the problem that the fringe center of line structured light cannot be extracted accurately and quickly,a fringe center extraction algorithm based on improved skeleton gray center method is proposed.Firstly,the fringe image is filtered and denoised,and then the ROI region is segmented by binarization.For the ROI region,the thinning algorithm is used to roughly extract the fringe center.After deburring and redundant points,the least square method is used to fit the straight line,and the adaptive width gray center of gravity method is used to extract the sub-pixel center point in the normal direction.The experimental results show that the accuracy of this method is improved by10% and the running time is reduced by 17% compared with the skeleton gray center method.(3)Aiming at the problem of wheel and rail 3D reconstruction,a wheel and rail 3D reconstruction method based on multi-sensor line surface structured light mixing is proposed,and a wheel and rail 3D reconstruction system is designed and built.This paper puts forward the equipment layout and selection of the system,and designs the software and hardware modules of the system.Gray phase shift coding is used to reconstruct the wheel and rail contact area based on surface structured light;The axle reconstruction is realized by multi line structured light.Aiming at the difficulty that multiple single line structured light planes cannot be parallel,this paper proposes a parallel light plane determination method based on standard parts,and realizes the correction of line structured light plane through projection transformation.The experimental results of wheel and rail reconstruction on the 1:1 wheel and rail test-bed in the laboratory verify the effectiveness of this method.