I was wondering whether anybody could advise me on a way to calculate the elevation angle from a camera to an object in an aerial photograph taken from a known elevation with no suitable reference objects.
Ultimately I would like to measure particular features within an image. I was thinking of a solution using trigonometry. Attached is a diagram illustrating the problem, as well as a sample of a picture to apply this to.
In the diagram, A represents the position of the camera. The Red triangle represents the focal view of the images. B is the centerpoint of the images. The Blue rectangles are objects I would like to measure.
To do it this way, I need to solve either angle E or F, however given that there is not tilt/angle/axis data stored within the photos EXIF metadata, I think the only way to do this would be to project the ground plane onto the image which I believe will allow me to calculate angle F. However I am unsure or unaware of whether there is software which may make this feasible?? As the goal would be for the solution to be applied to a series of photographs where the elevation angle could vary widely.
There aren't parallel lines, shadows, or objects of known size. However, topography shouldn't be an issue as the surface is flat (see image of ice).