Camera servo Tracking The camera is mounted on 1 or 2 servos for horizontal and/or vertical movement. The camera module will move the servos to keep the detected object in the center of the screen.

Wall-e will follow a ball with its head because the camera is moved by the servos. Watch this video for an example:

Camera servo Tracking Relative Will move the specified servos into a position relative to the object detected. This is good when your camera is stationary and not moving. Rather than moving the camera, it moves servos. This is good if you have a gun or something to aim at an object. Here is a video of a robot arm moving to point at the detected object

Here is another using the eyes of a robot head

Thanks for a very complete answer. I have watched the 1st and 3rd video many times. It was the addition of the 2nd video that cleared it up for me. Thanks again for your patience.

I can't wait until we get this working. We will post a video.