Explain hand–eye calibration and its purpose.

• A. Determines the rigid transform between the camera frame and the robot end-effector or base frame so captured images can be mapped to robot coordinates.
• B. Aligns the robot's mechanical axes with the floor.
• C. Calibrates the robot's gripper grip strength.
• D. Set the robot's home position.

Answer: (A)

Hand–eye calibration is about figuring out the exact spatial relationship between a camera and the robot’s hand (end-effector) or base, so that measurements from the camera can be expressed in the robot’s coordinate system. The result is a rigid transform that includes both rotation and translation between the camera frame and the robot frame. With this transform, any feature the camera sees—such as the position of an object in the image—can be converted into real-world robot coordinates. That makes it possible to plan precise pick-and-place, alignment, or manipulation tasks based on visual data. In practice, this involves collecting synchronized observations of known robot motions and solving for the transform that links the two reference frames (often formulated in a mathematical AX = XB form). The other options describe unrelated things like leveling with the floor, gripping force, or home positioning, which do not enable mapping image data to robot coordinates.