Reserch On Rapid Positioning And Identification Of Tunnel Contour

With the rapid development of high-speed railway, the ratio of tunnel line is bulging, and late disease detection is increasingly important after the construction having been completed. Tunnel section deformation detection is of the top priority of for the tunnel detection. And traditional detection methods of tunnel profile obviously does not meet the much testing needs, so rapid detection method of tunnel contour is urgent. So this thesis proposes a cross-section measurement program which installs laser rangefinder sensors with ring-direction but not equidistant in this context, combined with the already detection methods of tunnel section, it is a fast, simple and economic detection program for tunnel section detection. The main work is as follows:(1) Proposes a positioning of tunnel contour and measurement system start-stop method. tunnel contour positioning fixes mileage positioning with RFID assisted, measurement system start-stop is determined by setting electronic tag the in the entrance of tunnel、end of tunnel to correcting mileage position.(2) Studies the layout of the laser ranging sensors, proposes a method of tunnel structure surface detection using combined calibration with camera and laser distance sensor, combined calibration with camera and laser rangefinder camera sensor restores camera depth information.(3) Considering to section features of tunnel structure, proposes cubic B-spline fits the tunnel profile and surface, the tunnel section contour fitting, cubic B-spline fits straight wall type tunnel, cubic spline fits arc tunnel. Studies on the identification of tunnel section, which uses primitive recognition algorithm based on curvature difference, and proposes the second adjustment algorithm of the feature points for the arc outline. Through control points inverse for tunnel three-dimensional contour data points, three-dimensional tunnel is reconstructed by bi-cubic B-spline curves, while extracting the section data specified, as a reference section for contour deformation, avoiding the troubles caused by traditional section measurement methods whose section need to be located or labeled.This thesis gives the Joint calibration expression of CCD cameras and laser range sensors. Post-processing algorithm of measurement data are tested with standard high-speed railway tunnel section, test results show the feasibility of the algorithm, which provides a theoretical basis and experimental methods for the actual cross-section detection system.