I have a camera mounted at some [x,y,z] looking at a figure on the

z=0 plane. Is there a way to derive the perspective transformation

matrix without knowing any of the angles that the camera is mounted at?

I can put a square (or anything else) of known dimensions on the z=0

plane to use for this calibration.

Any hints would be welcome. Everything that I have ever studied shows

how to create a perspective view but I have not been able to figure

out how to "reverse engineer" the problem.

Thanks a lot,

Tom....