Qualcomm is probably putting in a lot of effort to gather the calibration data for all of the Android devices out there. Vuforia may be the only AR library that has so much information about all of these.
Now, we would like to add an innovative extension to the marker tracking that is being done, and for that we need the field of view of the physical camera (and/or the modified FOV of the image that appears on screen, in case it is clipped when the aspect ratio of the camera is different from that on the screen).
This cannot be retrieved from the FOV property of the ARCamera, since this always stays the same. Instead, Vuforia modifies the projection matrix of the camera directly...
So my question is: is it possible for us to retrieve the mentioned FOV(s) from (an undocumented) API function?
Or can we recompute it based on the values of the projection matrix? Perhaps by computing the angle between the normals of the side-planes of the view-frustrum? (at the moment I have no idea on how to actually do that though.. but since Daniel W would probably need all of five minutes to whip up some formulas, I thought I'd ask here :-)