Calculate diagonal field of view

Hi all,

Can someone help me out with calculating the camera's diagonal field of view.

I have the vertical (obviously ) and horizontal already but I need the diagonal one.

I am using the default camera so no access to sensor size or focal length.

-Pieter

 

Check out the

.fieldOfView

property on the

Camera

object.

Field of view in this particular Unity3D camera context refers to half the angle between your eye and the top and bottom of the frame, i.e., the vertical angle of view.

Lateral angle of your frame is dependent on screen aspect, and that is given by the expression

(float)Screen.width / Screen.height

. That will give you the lateral angular field of view, given the vertical angle.

The pythagorean theorem should therefore be able to give you the diagonal angle, based on vertical and lateral fields of view.

 

Thanks for your reply and apologies for not replying sooner - just got back behind the computer.

I believe it is not as simple as you describe and I already gave that a try before posting my question - it is not giving me correct results. I should have been more clear on that.

Calculating the horizontal field of view is done as stated here https://forum.unity.com/threads/how-to-calculate-horizontal-field-of-view.16114/

I have some code that converts diagonal to vertical.

I need something similar for diagonal fov - still messin with it

 

The diagonal can be calclated using pythagorean theorem, but you have to apply it to the linear sizes of the screen (not FOVs) and then get back to an angle. These are the conceptual steps:

Vertical FOV -> screen height -> screen width -> diagonal -> Diagonal FOV​

In code:

Code (CSharp):

1. float radAngle = cam.fieldOfView * Mathf.Deg2Rad;
2. float vTan = Mathf.Tan(radAngle / 2f);
3. float hTan = vTan * cam.aspect;
4. float dTan = Mathf.Sqrt(hTan * hTan + vTan * vTan);
5. float radDFOV = 2f * Mathf.Atan(dTan);
6. diagonalFOV = Mathf.Rad2Deg * radDFOV;