Automatic detection method of shield tail gap without reference object by machine vision

Abstract

The invention discloses a method for automatic detection of shield tail gaps without a machine vision reference object, comprising: directing a CCD camera toward the center of the segment and centering it, setting the range of the CCD camera; using the CCD camera to take initialization pictures to initialize The center coordinates of the picture are the origin to establish a CCD coordinate system, and obtain the left line pixel L and right line pixel R of the segment in the initialization picture; calculate the shield tail gap d of the initialization segment 初 :D 初 = d m ‑(2R‑Y)h / Y, where d m is the shield tail gap value obtained by manual measurement during initialization calibration, h is the thickness of the segment, Y=L+R is the pixel value of the segment width; during the shield tunneling process, the segment image is captured in real time by the CCD camera to obtain the segment The left line pixel L and the right line pixel R in the image are substituted into the formula (1) to calculate the shield tail gap d: d=d 初 +(R-L)h / Y(1). The invention solves the technical problem that the shield tail gap is detected by the moving segments without effective reference boundary information (no stable relative reference point) on the inner wall of the shield tail in the field of view.

Description

technical field [0001] The invention relates to the technical field of shield construction quality and safety monitoring, in particular to an automatic detection method for shield tail gaps without reference objects by machine vision. Background technique [0002] During the tunnel construction process, the distance between the outer circle of the segment circumferential surface in contact with the shield jack shoe plate and the inner wall of the shield shell is called the shield tail clearance. During the excavation process of the shield, the values ​​of the shield tail clearance are closely related to the changes of the tunnel design axis (DTA), the deflection correction measures of the shield, the gravity deformation of the shield tail shell and the formed segment, and other factors. [0003] Shield construction must strictly monitor the change of shield tail clearance. The correct shield tail gap data can reflect the forming axis position of the assembled segment, and p...

AI Technical Summary

Problems solved by technology

However, manual measurement of the shield tail gap is time-consuming and laborious, and the measurement accuracy is unstable

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