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On the Use of Microwave Holography to Detect Surface Defects of Rails and Measure the Rail Profile
Andrey Zhuravlev1, Vladimir Razevig2, Sergey Ivashov3
1Remote Sensing Laboratory, Bauman Moscow State Technical University, Moscow 105005, Russia. azhuravlev@rslab.ru.
Abstract:
The use of microwave holography for detecting rail surface defects is considered in this paper. A brief review of available sources on radar methods for detecting defects on metal surfaces and rails is given. An experimental setup consisting of a two-coordinate electromechanical scanner and a radar with stepped frequency signal in the range from 22.2 to 26.2 GHz is described, with the help of which experimental data were obtained. Fragments of R24 rails with surface defects in their heads were used as the object of study. The radar images of rail defects were obtained by the described method based on back propagation of a wavefront. It is shown that polarization properties of electromagnetic waves can be used to increase the contrast of small-scale surface defects. A method of estimating rail surface profile by radar measurements is given and applied to the experimental data. Comparison of the longitudinal rail head profiles obtained by radar and by direct contact measurements showed that the radar method gives comparable accuracy.
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