The3D Measurement And Limit Detection For The Train Body Based On Line Laser

Railway vehicles limit of detection refers to the maximum dynamic envelope ofvehicle in normal state. The traditional detection method using a variety of test equipmentand tooling, limit template, and so on. When it’s detection, the train gets through the limitgate slowly and the workers observe the gap between all parts of the vehicle and limitdoor artificially. Then workers judge the processing quality of vehicle body qualitatively.As the rapid development of digital circuit, computer technology, and opticalinstrument which is represented by laser device and CCD cameras, the3D laser visionmeasuring has been more and more used in quality test of products, industrial on-linedetection, reversal design, digitalization of cultural relics, human body shape measurement,biomedical and other fields. The space size automatic measurement technology based onlaser3D vision has advantages like multi-point measurement, real-time display,contactless and automation, etc.In order to make the vehicle inspection more accurate and automated, in this paperwe studied some key technologies of the measurement based on3D line laser vision andcarried out feasibility experiment in simulated environment. The key technologies includelaser visual model for3D measurements, laser stripe center extraction, camera calibration,laser plane calibration, etc. Also we set up the experimental platform and carried outsimulation experiment.In the simulation experiment, we use high precision vertical motion platform to drivelaser generators and high resolution CCD cameras for translation, simulating the relativemovement between the train body and detection gantry. In this experiment method,multiple laser generators are used to project laser lines from different directions on theobject and multiple CCD cameras capture the laser line images correspondingly, and the3D points are reconstructed by triangulation method. The laser generators and cameras areall fixed on two lift tables, and as the lift tables go down the object section will be scannedcompletely.After calibration, the measurement system was tested, including precision test andfunction test. The experiment results are presented to illustrate technology research andimplementation processes are effective and feasible in this paper. The measurementsystem works stable, precisely and the experiment results are satisfied.