I am working on a small project wherein I am estimating the distance to an object of a known size, both physical and pixel dimensions.
So far I have used a triangle similarity approach and I have measured the distance down to a few millimeters in deviation from the actual distance. With that approach, I calculated a focal length of my camera using the specific pixel height of the object at a known distance. However, that was before I tilted the camera.
What approach can I take now that the camera is tilted?