Structured light laser scanning. Application to the inspection of railway components

摘要

A laser scanner device is used to obtain a 3D digital representation of an object. The method uses a laser with a refractive element in order to generate a laser light plane. The intersection of the light plane with the object delineates a cross section of it; the image of that curve is acquired by a digital camera, stored and processed by a program developed by the authors. The displacement of the light plane with respect to the object allows obtaining several cross sections of its surface which are combined to produce the 3D representation. The laser scanning system uses two sensors to record parts that would remain otherwise hidden when using a single sensor. Calibration of the sensors is described for a single frame of reference, as well as the algorithms to correct for geometric distortion and obtain the laser line representing the profile of the object studied. This paper presents an experimental system of inspection of geometrical defects to assess the main components involved in the running of trains: rails and wheels. This system may be suitable for operation either in the workshop or on the railways.