I am trying to write a program that can show the worth of a coin in an image.
I have already took care of finding radius of coins in pixel. But I am stuck here: if the image has been taken from a distance of
h millimeters with angle of $90$ degrees, and lets say a coin in the image has radius of
p pixels, how can I calculate the diameter of the coin ($d = p * 2$) in
I just want to know the possible mathematical approach to solve this, the coding should be ok to do. Sorry if this question may not be related here.