Using reference objects to improve vision-based bearing measurements

Robots perceiving its environment using cameras usually need a good representation of how the camera is aligned to the body and how the camera is rotated relative to the ground. This is especially important for bearing-based distance measurement. In this paper we show how to use reference objects to improve vision-based distance measurements to objects of unknown size. Several methods for different kinds of reference objects are introduced. These are objects of known size (like a ball), objects extending over the horizon (like goals and beacons), and objects with known shape on the ground (like field lines). We give a detailed description how to determine the rotation of the robot’s camera relative to the ground, provide an error-estimation for all methods and describe the experiments we performed on an Aibo robot.

Authors

• Heinrich Mellmann
• Matthias Jüngel
• Michael Spranger

Keywords

• Cameras
• Robots
• Robot vision systems
• Distance measurement
• Joints
• Robot sensing systems
• Robot kinematics
• Reference Object
• Distancing Measures
• Field Lines
• Over The Horizon
• Proprioceptive
• Image Object
• Methods In Order
• Object Classification
• Optical Axis
• Imaging Center
• Distance Calculation
• Tilt Angle
• Cervical Vertebrae
• Camera Position
• Roll Angle
• Effect Of Rotation
• Angle Error
• Humanoid Robot
• Joint Data
• Kinematic Chain
• Camera Orientation
• Ball Position
• Camera Height
• Ball Size
• Object Distance
• RoboCup
• Aibo
• mobile robots
• robotic vision
• camera matrix
• reference objects