An automatic extraction method for the transverse diameter of a subway circular shield tunnel

Abstract

The patent of the present invention belongs to the field of deformation detection of tunnel structures, and is a method for automatically extracting the section diameter of the point cloud of the three-dimensional laser scanning of the shield tunnel. ;2) Use the tunnel point cloud to generate a grayscale image of the inner wall of the tunnel; 3) Identify the positions of the waist seams on both sides of the ring piece by ring; 4) Automatically extract the points 0.813m below the waist seams on both sides as the reference for diameter extraction;5 ) Calculating the transverse diameter of the ring piece ring by ring according to the reference point of diameter extraction; 6) Automatically detecting the quality of diameter extraction ring by ring, and manually intervening and correcting the diameter of poor quality to correct the position of the reference point. The advantages of the present invention are: by automatically extracting the reference point for diameter calculation used in the traditional total station measurement in the point cloud, the extraction accuracy of the section diameter is improved, and the problem of the low precision of the ellipse fitting extraction algorithm commonly used in the prior art is solved Problems can be better integrated with the measurement results of the total station.

Description

technical field [0001] The patent of the invention belongs to the field of deformation detection of tunnel structures, and is an automatic extraction method of cross-section diameter for three-dimensional laser scanning point clouds of subway shield tunnels. Background technique [0002] After the subway shield tunnel is completed, due to the impact of trains and external forces, the tunnel often deforms. In order to understand the amount of deformation, it is necessary to measure the subway tunnel regularly. At present, the commonly used measurement method is: pre-arrange the diameter measurement reference point at the chord length of 0.813m below the waist seam on both sides of a ring in the tunnel, and then use the total station to measure the prism-free coordinates of the diameter measurement reference point, and calculate the two The distance between the side reference points, as a measurement of the tunnel ring diameter. [0003] As the scale of underground rail trans...

AI Technical Summary

Problems solved by technology

However, for tunnel point cloud processing and extraction of tunnel diameter, there is no effective method. At present, the commonly used technical method is to slice and extract the point cloud of a certain ring, fit each ring point cloud to an ellipse, and extract the long axis of the ellipse as Current disc diameter measurement

However, it has been found through practical application that due to the difference in measurement methods and technical means, the segment diameter obtained by using the point cloud ellipse fitting method has a large gap compared with the diameter measurement results of the traditional total station, the data is difficult to integrate, and the external coincidence accuracy cannot be achieved. ensure

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