Hand-eye calibration description

  • Hand-eye calibration

    It refers to the process of calculating the transformation relationship between the robot coordinate system and the camera coordinate system by collecting the calibration object pose and robot pose captured by the camera. Using the calculated transformation matrix, the target point in the camera coordinate system can be converted to the robot coordinate system, thereby realizing the 3D vision-guided operation. The accuracy of hand-eye calibration is crucial and will directly affect the accuracy and stability of the system.

  • Camera installation

    Installation method

    Description

    Illustration

    Eye in hand (EIH)

    The camera is installed at the end of the robot and is relatively fixed to the flange coordinate system. The camera moves with the end of the robot.

    alt

    Eye to hand (ETH)

    The camera is installed in a fixed position, and its relative position to the robot base coordinate system remains unchanged.

    alt

  • Point pair data

    A pair of pose information of the same feature point in the camera and robot coordinate systems.

Hand-eye calibration tutorial

Please refer to the corresponding hand-eye calibration tutorial according to the actual situation.

Scene

Tutorial

Hand-eye calibration in the eye-to-hand (ETH) scenario

Eyes outside the hand - three-axis robot

Eyes outside the hand - Four-axis robot

Eyes outside the hand - Six-axis robot

Hand-eye calibration in the eye-in-hand (EIH) scenario

Eye in hand - Three-axis robot

Eyes in Hand - Four-axis Robot

Eye in hand - Six-axis robot

When to recalibrate hand-eye

Hand-eye calibration needs to be recalibrated when the following situations occur.

  • Replace the camera or robot.

  • In the eye-to-hand scenario, the camera position changes relative to the robot base coordinate system.

  • In the eye-in-hand scenario, the camera position changes relative to the robot flange coordinate system.