title: Computer vision based method and system for online measurement of geometric parameters of train wheel sets.
abstract: Train wheel sets must be periodically inspected for possible or actual premature failures and it is very significant to record the wear history for the full life of utilization of wheel sets. This means that an online measuring system could be of great benefit to overall process control. An online non-contact method for measuring a wheel set's geometric parameters based on the opto-electronic measuring technique is presented in this paper. A charge coupled device (CCD) camera with a selected optical lens and a frame grabber was used to capture the image of the light profile of the wheel set illuminated by a linear laser. The analogue signals of the image were transformed into corresponding digital grey level values. The 'mapping function method' is used to transform an image pixel coordinate to a space coordinate. The images of wheel sets were captured when the train passed through the measuring system. The rim inside thickness and flange thickness were measured and analyzed. The spatial resolution of the whole image capturing system is about 0.33 mm. Theoretic and experimental results show that the online measurement system based on computer vision can meet wheel set measurement requirements.
authors.affiliation: Department of Physics, Zhengzhou University of Light Industry, Zhengzhou, 450002, China. zhifengzhang76@gmail.com
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Zhang
authors.forename: Zhan
authors.initials: Z
authors.lastname: Gao
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Liu
authors.forename: Feng-Chun
authors.initials: FC
authors.lastname: Jiang
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Yang
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Ren
authors.forename: Hong-Jun
authors.initials: HJ
authors.lastname: Yang
authors.forename: Kun
authors.initials: K
authors.lastname: Yang
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Zhang
mesh_terms: D001185:Artificial Intelligence; D002138:Calibration; D019544:Equipment Failure Analysis / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D009862:Online Systems; D010781:Photography / Q000295:instrumentation; D014186:Transportation / Q000295:instrumentation*