math - Calculate angle of view from 2D image -

math - Calculate angle of view from 2D image -

i want calculate angle of view (or field of view) photograph, without knowing camera, utilize info in 3d environment.

i have utilize trigonometry solve (most using arctan), i'm not proficient plenty in math ... can please help?

please have @ example.

i assume angle between line center-left , center-right 90° in reality.

i know distances (in pixels) of point c vanishing points vp-left , vp-right.

furthermore height of image angle of view in 3d environment.

thanks!

math trigonometry