[Mr. Lim]

Originally Posted by Lil' Lavery

So you're assuming that as your distance from the target changes, so will its height in your camera's field of vision at a predictable rate? I'd recheck that assumption if I were you. If you're only moving in the axis orthogonal to the goal, this would be true. But does it hold true once you introduce the second (or third) axes of motion?

This is true, and we did it last year with EdgeWalker.

If the camera is kept at a fixed height, and a fixed angle, and you are directly in front of the goal, you've essentially limited your movement to the axis orthogonal to the goal. If you move left and right (perpendicular axis) the shape of the goal becomes trapezoidal, but if you use the centre of the bounding box of the trapezoid as your reference, you can compensate for the additional axis of movement.

The trick is finding a camera height and angle where there is enough change in the goal's height to give you meaningful information - AND where you can keep the goal in the field of view at every spot on the field you want to shoot from.