Modeling and Analysis of a Humanoid Robot Active Stereo Vision Platform

Humanoid robot is not only expected to walk stably, but also is required to perform manipulation tasks autonomously in our work and living environment. This paper discusses the visual perception and the object manipulation based on visual servoing of a humanoid robot, an active robot vision model is built, and then the 3D location principle, the calibration method and precision of this model are analyzed. This active robot vision system with two DOF enlarges its visual field and the stereo is the most simple camera configuration for 3D position information.

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Neural-network-based 3-D localization and inverse kinematics for target grasping of a humanoid robot by an active stereo vision system

The 2012 International Joint Conference on Neural Networks (IJCNN) ◽

10.1109/ijcnn.2012.6252400 ◽

2012 ◽

Cited By ~ 5

Author(s):

Chih-Lyang Hwang ◽

June-Yun Huang

Keyword(s):

Neural Network ◽

Stereo Vision ◽

Inverse Kinematics ◽

Humanoid Robot ◽

Vision System ◽

Stereo Vision System ◽

Active Stereo

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Flexible method for accurate calibration of large-scale vision metrology system based on virtual 3-D targets and laser tracker

International Journal of Advanced Robotic Systems ◽

10.1177/1729881419893516 ◽

2019 ◽

Vol 16 (6) ◽

pp. 172988141989351

Author(s):

Xi Zhang ◽

Yuanzhi Xu ◽

Haichao Li ◽

Lijing Zhu ◽

Xin Wang ◽

...

Keyword(s):

High Precision ◽

Stereo Vision ◽

Large Scale ◽

Vision System ◽

Calibration Method ◽

Field Of View ◽

Large Field ◽

Laser Tracker ◽

Calibration Target ◽

Pose Tracking

For the purpose of obtaining high-precision in stereo vision calibration, a large-size precise calibration target, which can cover more than half of the field of view is vital. However, large-scale calibration targets are very difficult to fabricate. Based on the idea of error tracing, a high-precision calibration method for vision system with large field of view by constructing a virtual 3-D calibration target with a laser tracker was proposed in this article. A virtual 3-D calibration target that covers the whole measurement space can be established flexibly and the measurement precision of the vision system can be traceable to the laser tracker. First, virtual 3-D targets by calculating rigid body transformation with unit quaternion method were constructed. Then, the high-order distortion camera model was taken into consideration. Besides, the calibration parameters were solved with Levenberg–Marquardt optimization algorithm. In the experiment, a binocular stereo vision system with the field of view of 4 × 3 × 2 m3 was built for verifying the validity and precision of the proposed calibration method. It is measured that the accuracy with the proposed method can be greatly improved comparing with traditional plane calibration method. The method can be widely used in industrial applications, such as in the field of calibrating large-scale vision-based coordinate metrology, and six-degrees of freedom pose tracking system for dimensional measurement of workpiece, as well as robotics geometrical accuracy detection and compensation.

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Experiments on mobile robot stereo vision system calibration under hardware imperfection

MATEC Web of Conferences ◽

10.1051/matecconf/201816103020 ◽

2018 ◽

Vol 161 ◽

pp. 03020 ◽

Cited By ~ 1

Author(s):

Ramil Safin ◽

Roman Lavrenov ◽

Subir Kumar Saha ◽

Evgeni Magid

Keyword(s):

Mobile Robot ◽

Stereo Vision ◽

Experimental Approach ◽

Vision System ◽

Robot Vision ◽

System Calibration ◽

Stereo Vision System ◽

Calibration Methods ◽

Vertical Level ◽

Grid Based

Calibration is essential for any robot vision system for achieving high accuracy in deriving objects metric information. One of typical requirements for a stereo vison system in order to obtain better calibration results is to guarantee that both cameras keep the same vertical level. However, cameras may be displaced due to severe conditions of a robot operating or some other circumstances. This paper presents our experimental approach to the problem of a mobile robot stereo vision system calibration under a hardware imperfection. In our experiments, we used crawler-type mobile robot «Servosila Engineer». Stereo system cameras of the robot were displaced relative to each other, causing loss of surrounding environment information. We implemented and verified checkerboard and circle grid based calibration methods. The two methods comparison demonstrated that a circle grid based calibration should be preferred over a classical checkerboard calibration approach.

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