1 | initial version |
So, the answer is, it's complicated.
The big problem with the laser or radar device is pointing it at the ball. Lasers are, obviously, very narrow, and you'll need that for position. That radar gun probably won't work on golf balls, so you'd need a better one, and it is probably narrow too.
For two cameras, there are three main factors driving accuracy. All assuming you can track the ball. If you can't reliably detect and track the ball in both cameras, you're not going to be able to do it at all.
With the right choice of algorithm, you can mitigate 1 and 2 by adding more than two cameras. The noise and biases will (hopefully) cancel out as you add more cameras, giving you a more accurate result.
If you want to play with things, I have an OpenCV contrib module that I am (slowly) working on. Right now it calculates 3d position or position and velocity from a series of camera measurements. You input time, the location of the object in the image, camera matrix, distortion matrix, camera translation and rotation, and the size of the image. With a moving camera (or more than one stationary camera), it can give position or position and velocity.