Calculating line of sight angles from a photograph.

Question

I have 2 photographs of the same side of a textured sphere taken from slightly different angles. How can I determine the angle between each photographers line of sight?

Answer 1

I am assuming that there is a [distant] light source somewhere, so that there is a lit portion, and a shaded portion, to the sphere. If so, the boundary between the two portions defines the plane [through the center of the sphere, if the light source is distant enough] perpendicular to the direction towards the light source. Understanding that would be the first step towards solving your puzzle.

Answer 2

If you took the shots from the same point; you need to use trig. You are at point "alpha". The distance to the first picture/point is side "c". To the 2nd picture/point is side "b". "a" is the distance between the 2 picture/points.

You want "alpha". Since there's no given angle; there's formulas.

"alpha"=acos((b^2+c^2-a^2)/(2bc))

"alpha" is located across from side "a"; "beta" opposite side "b"; "gamma" opposite side "c"

Note: acos=what is "alpha" the cos of?