Estimating Caster Using a Digital Camera

That is exactly how, in principle, caster is always measured in a shop. I would use turn plates (two pieces of plywood with some grease or a plastic bag between them), I would turn 20 degrees each way rather than full lock, and I use a digital protractor or a camber gauge to measure the camber, but that is in essence exactly how caster is measured. Race shops all over the country do that all the time. Astounding precision in the measurement technique isn't required, because as long as you do it the same way for all the measurements the errors tend to cancel out. For years I measured camber on my race cars with a level and a tape measure and a little math.

Brian