US 12,306,421 B2
Electro-hydraulic varifocal lens-based method for tracking three-dimensional trajectory of object by using mobile robot
Shaorong Xie, Shanghai (CN); Hengyu Li, Shanghai (CN); Jingyi Liu, Shanghai (CN); Yueying Wang, Shanghai (CN); Shuang Han, Shanghai (CN); and Jun Luo, Shanghai (CN)
Assigned to SHANGHAI UNIVERSITY, Shanghai (CN)
Filed by SHANGHAI UNIVERSITY, Shanghai (CN)
Filed on Aug. 30, 2022, as Appl. No. 17/899,264.
Claims priority of application No. 202111006409.0 (CN), filed on Aug. 30, 2021.
Prior Publication US 2023/0063939 A1, Mar. 2, 2023
Int. Cl. G02B 3/14 (2006.01); G05D 1/00 (2006.01)
CPC G02B 3/14 (2013.01) [G05D 1/0246 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An electro-hydraulic varifocal lens-based method for tracking a three-dimensional (3D) trajectory of an object by using a mobile robot, comprising:
step 1, calibrating and modeling an electro-hydraulic varifocal lens, selecting a to-be-tracked moving object using an object tracking algorithm, and obtaining an object tracking box;
step 2, carrying out autofocusing on the tracked object using the electro-hydraulic varifocal lens, and recording a focusing control current after the autofocusing is completed, a size of the object tracking box, center point coordinates after undistortion, and four angular point coordinates, and calculating spatial coordinates of the object under a camera coordinate system;
step 3, generating a mask of the moving object with the four angular point coordinates of the object tracking box, and calculating, by a Visual Simultaneous Localization and Mapping (V-SLAM) system, a transformation matrix of the camera coordinate system on the mobile robot with respect to a world coordinate system;
step 4, transforming the spatial coordinates of the moving object under the camera coordinate system to the world coordinate system and recording corresponding world coordinates, calculating a movement velocity and direction of the object in combination with world coordinates of the object at a previous moment, and updating a movement velocity and direction of the mobile robot; and
step 5, repeating steps 2 to 4 to continuously track the 3D trajectory of the object.