Microsoft Lifecam Angle

We are trying to use a Microsoft LifeCam HD-3000 on our robot. However, in order to perform some of the functions we want on it, we need to know the angle of camera.

A comment in the 2015 Vision Retro Sample given in the wpilib plugin states that the angle for what we want (HD3000 640x480) is 60 degrees, which we were going to use.

However, I have read the Technical Data Sheet for this camera and have come to some interesting conclusions. The data sheet states that the camera is a 1280x720 camera, and that it has a 68.5 degree diagonal angle(I assumed that the comment on the retro sample was referring to a diagonal angle as well, but it didn’t specify). To make the ratio work, I first calculated what the angle would be if horizontal view was cropped and the height remained the same, which would be a 55.97 degree diagonal axis. I then calculated the diagonal angle if they just cropped a 640x480 from the middle of the image, which would come to 37.31 degrees.

I am unsure if I am bad at math (definite possibility) or whether the angle given in the comment was inaccurate, but we need to be sure the angle is correct to code the camera properly. What diagonal angle are you using in your code?

It might simply be the difference between a diagonal angle of view vs a horizontal angle of view.
e.g., although this example is only an approximation

See also “Measuring a camera’s field of view” in