I'm looking to find the proper formulas and/or Matlab code to localize a point within a circle given 2 points on the circumference. The points will be acquired by an image panel that rotates about a fixed axis. The hitch is that I am using flat image panels that are tangent to the circle at their center. I would like to measure the offset of a small spherical object from the center of the panel at 2 different positions on the circumference, extend a vector normal to the image panel from where that object appears on the images, and locate the point where the two vectors intersect (the position of the object within the circle). How can I go about doing this? Your help is much appreciated!