	US 12,259,227 B2
	Method for monitoring large deformation of tunnel surrounding rock based on automatic target tracking and ranging system
Lubo Meng, Chengdu (CN); Junqi Fan, Chengdu (CN); Guosong Sun, Chengdu (CN); Fuli Kong, Chengdu (CN); Tianbin Li, Chengdu (CN); Xiaoyan Shi, Chengdu (CN); Wei Zhou, Chengdu (CN); Enlai Liu, Chengdu (CN); and Xing Zhu, Chengdu (CN)
Assigned to Chengdu University of Technology, Chengdu (CN)
Filed by Chengdu University of Technology, Chengdu (CN)
Filed on Feb. 7, 2022, as Appl. No. 17/666,297.
Claims priority of application No. 202110169574.1 (CN), filed on Feb. 7, 2021.
Prior Publication US 2022/0252387 A1, Aug. 11, 2022
Int. Cl. G01C 3/08 (2006.01); E21F 17/00 (2006.01); G01B 11/16 (2006.01); G06T 7/73 (2017.01); H04N 23/695 (2023.01)

CPC G01B 11/16 (2013.01) [E21F 17/00 (2013.01); G06T 7/73 (2017.01); H04N 23/695 (2023.01); G06T 2207/20084 (2013.01); G06T 2207/30181 (2013.01)]

9 Claims

1. A method for monitoring large deformation of a surrounding rock of a tunnel based on an automatic targeting and ranging system, wherein the automatic targeting and ranging system comprises a left camera module, a left laser ranging module, a plurality of left wall targets, a right camera module, a right laser ranging module, a plurality of right wall targets and a vault target; the left camera module and the left laser ranging module are bound on a left side wall of a cross section of the tunnel and are rotatable counterclockwise synchronously on the cross section of the tunnel; the plurality of left wall targets are spaced apart on a left wall of the cross section of the tunnel; the right camera module and the right laser ranging module are bound on a right side wall of the cross section of the tunnel and are rotatable synchronously clockwise on the cross section of the tunnel; the plurality of right wall targets are spaced apart on a right wall of the cross section of the tunnel; and the vault target is provided at a vault position of the cross section of the tunnel;

the method for monitoring the large deformation of the surrounding rock of the tunnel comprises an automatic targeting and ranging stage and a tunnel deformation calculation stage;

wherein for each target of the plurality of left wall targets, the plurality of right wall targets and the vault target, the automatic targeting and ranging stage comprises the following steps:

rotating a camera module and a laser ranging module corresponding to a target from a horizontal position, wherein the camera module is the right camera module corresponding to the plurality of left wall targets or the vault target, and the laser ranging module is the right laser ranging module corresponding to the plurality of left wall targets or the vault target; alternatively, the camera module is the left camera module corresponding to the plurality of right wall targets or the vault target, and the laser ranging module is the left laser ranging module corresponding to the plurality of right wall targets or the vault target;

when the camera module and the laser ranging module are rotated to an initial target alignment angle corresponding to the target, acquiring, by the camera module, a target monitoring image comprising a target image, wherein the initial target alignment angle refers to a rotation angle of rotating the laser ranging module from the horizontal position to allow the laser ranging module to be aligned with the target when the target is arranged;

determining a center image position of the target in the target monitoring image;

adjusting rotation angles of the camera module and the laser ranging module according to the center image position, to allow the laser ranging module to be aligned with the target;

calculating a current target alignment angle according to the initial target alignment angle and adjusted rotation angles; and

acquiring, by the laser ranging module, a current distance value from the laser ranging module to the target;

wherein the tunnel deformation calculation stage comprises: calculating a deformation offset of each target of the plurality of left wall targets, the plurality of right wall targets and the vault target according to the current target alignment angle, the current distance value, the initial target alignment angle and an initial distance value corresponding to the target, wherein the initial distance value refers to a distance value from the laser ranging module to the target first acquired by the laser ranging module in an alignment attitude when the target is arranged;

wherein the step of calculating the deformation offset of each target of the plurality of left wall targets, the plurality of right wall targets and the vault target according to the current target alignment angle, the current distance value, the initial target alignment angle and the initial distance value corresponding to the target comprises:

calculating the deformation offset FF′ of each target as follows:

wherein, d₀denotes the initial distance value corresponding to the target; θ₀denotes the initial target alignment angle corresponding to the target; d_v,0denotes an initial distance value corresponding to the vault target; θ_v,0denotes an initial target alignment angle corresponding to the vault target; d_τ denotes the current distance value corresponding to the target; θ_τ denotes the current target alignment angle corresponding to the target; d_v,τ denotes a current distance value corresponding to the vault target; and θ_v,τ denotes a current target alignment angle corresponding to the vault target.