Programming archery auto scoring software

Hi i'm looking for someone either to create an archery auto scoring software or advice me on how to do it, i want it to use a camera to take photos to compare together and then by addentifying the difference in it finding the distance away from the centre of the image to calculate the score of the arrow, i would then like it to put the result into a score sheet.
I have two apps on my iphone to score arrows but would like an sutomatic scoring system that i can set up and leave to score. i can provide further details for example size of targets, distances, other archery related information you would need.