Using the Effect of Reflected-Light Polarization for Remote Detection of Rail Defects

A new method is proposed for contactless optical diagnostics of railroad bed, which makes it possible to reveal local defects of rails (waves, cracks, etc.) and can provide the immediacy of railway line inspection using the remotely-piloted flying vehicles and other types of aircrafts. The fault-detection method consists in recording the light reflected from the rail's top surface (which becomes partially polarized in this case) using a photodetector equipped with a polarization filter. For description of polarized light, the Stokes vector is chosen because with its help it is easier to analyze the light beam transmission through optical systems. It is shown that the subsequent algorithmic processing of the obtained images makes it possible to enhance the defect contrast in comparison with the contrast during the typical video recording. A series of experiments for checking the possibility of defect visualization directly on railway tracks were carried out, which confirmed the method efficiency. The method is new, so it is necessary to perform additional investigations for determination of optimal parameters ofpolarization survey taking into account the diversity of defects occurred.

References

[1] Bazulin E.G. SAFT imaging of flaws in the rail base blade with consideration of multiple reflections of an ultrasonic pulse from the boundaries of a test object. Russ. J. Nondestr. Test., 2010, no. 2, pp. 125-136. doi 10.1134/S1061830910020075.

[2] Podgornaya L.N. Razrabotka i issledovanie sistemy diagnostiki rel’sovogo puti na mikromekhanicheskikh chuvstvitel’nykh elementakh [Development and study of a system for the diagnosis of a rail track based on micromechanical sensor elements]. Avtoreferat diss. kand. tekhn. nauk [Cand. tehn. sci. diss. abstr.]. St. Petersburg. 15 p.

[3] Boronakhin A.M., Gupalov V.I., Mochalov A.V. Sposob inertsial’nykh izmereniy nerovnostey rel’sovogo puti [The method of inertial measurements of rail track irregularities]. Patent RF, no. 2242391, 2002.

[4] Khodorkovskiy Ya.I., Anuchin O.N., Gusinskiy V.Z., Emel’yantsev G.I. Sposob i ustroystvo kontrolya sostoyaniya rel’sovoy kolei [Method and equipment for monitoring rail tracks]. Inventor’s Certificate RF, no. 2123445, 1998.

[5] Olhoeft G.R., Selig E.T. Ground penetrating radar evaluation of railway track substructure conditions. Proc. SPIE, 2002, vol. 4758, p. 48.

[6] Eyre-Walker R.E.A., Earp G.K. Application of aerial photography to obtain ideal data for condition based risk management of rail networks. Proc. 4th IET Int. Conf. on Railway Condition Monitoring, Derby, UK, 2008.

[7] Vorob’ev E.V. Tekhnicheskaya ekspluatatsiya zheleznykh dorog i bezopasnost’ dvizheniya [Technical operation of railways and traffic safety]. Moscow, Marshrut Publ., 2005. 531 p.

[8] Sokolov A.V. Opticheskie svoystva metallov [Optical properties of metals]. Moscow, GIFML Publ., 1961. 464 p.

[9] Ivashov S.I., Razevig V.V., Levin B.A., Bugaev A.S., Vorob’ev V.B., Nedorchuk B.L. Sposob opticheskogo opredeleniya nerovnostey i defektov rel’sovogo puti [An optical method for determining irregularities and defects of a rail track]. Decision to grant Patent RF, no. 2012103268, 2013.

[10] Landsberg G.S. Optika [Optics]. Moscow, Fizmatlit Publ., 1976. 926 p.

[11] Shurcliff W.A. Polarized Light. Cambridge, Harvard Univ. Press, 1962. (Russ. ed.: Sherkliff U. Polyarizovannyy svet. Moscow, Mir Publ., 1965. 264 p.).

[12] Cremer F., Jong W., Schutte K. Infrared polarization measurements and modeling applied to surface-laid antipersonnel landmines. Opt. Eng. 2002, vol. 41, no. 5, pp. 1021-1032. doi: 10.1117/1.1467362.