Building a Coin Sorter

A while back I had the idea of building a device that would optically sort coins. I've always been fascinated by the gravity-fed machines that sort different sizes of coins into bins. I want to take it further. I would like to be able to sort my coins by date into different tubes not only by size, but also color, year, and maybe quality.

The first step for this, is to build a test rig that can hold a camera and different coins:

Once the computer+camera can make a repeatable good decision, I'll build a system to move the coins into different storage containers, but for now I'll settle for detecting different coins.