The HALCON operator, vector_to_pose, determines the 3D spatial relationship between the camera and world coordinate systems when given at least 4 known points or fiducials. It can be used for both hand-eye calibration as well as to determine the 3D pose of a known object in camera coordinates.
To perform hand-eye calibration using vector_to_pose, you need to move the robot to at least 4 known positions. The HALCON operator will then determine the pose of the robot base in camera coordinates. This is a very common technique to perform hand-eye calibration, and it can be applied to scara as well as articulated robots.
Another application of the operator is to determine the 3D pose of known objects. “Known” means that there must be at least 4 unique features that you can easily locate, e.g. with shape-based matching. The row and column positions in the image combined with the known coordinates of these features relative to the object will determine the object’s pose in camera coordinates.
In order for the operator to work reliably and produce accurate results, the camera must be calibrated, i.e. its intrinsic parameters like focal length etc. must be known. You can determine these parameters with HALCON’s 3D camera calibration.
Suggested HDevelop examples:
calibrate_hand_eye_scara_stationary_cam_approx.hdev
pose_of_known_3d_object.hdev
You can download HALCON for free, and request an evaluation license if you are not already using HALCON.