Combination-Chord Measurement of Rail Corrugation Using Triple-Line Structured-Light Vision: Rectification and Optimization

Abstract

Combination-chord model (CCM), specially designed to broaden the range of rail corrugation measurement, still faces two troubles including the measuring point deviation and the inverse filter parameters optimization. In this paper, a triple-line structured-light vision (SLV) based CCM is introduced to address these issues. Two solutions respectively for rectification of the measuring points deviation and optimization of the inverse filter parameters are presented. The former, based on the horizontal spacing constraint, detects the exact measuring point from a true rail profile which is reconstructed and rectified by the triple-line SLV. The latter, based on the minimum cumulative recovery error, defines the optimized numbers of frequency sampling and filter order, together with a splicing wavelength. Employing these optimized parameters, our CCM yields the overall amplitude-frequency response being nearly one whether for longwave corrugation or for shortwave corrugation. Both of the proposed solutions aim at enhancing the ordinary CCM in terms of the validity for rail corrugation measurement. Experimental assessments verify the availability and repeatability of our scheme.