I have piles upon piles of gears that I have collected to make gearboxes from.
When it comes time to make a gearbox, I get to have the fun of sorting thru
all the gears to nonally find sets that mesh, but sets that result in the 
ratio I'm targeting. 
The idea for a team project (I'm not the only one with this issue!)came up, 
to create software to classify gears, 
3 of us set up raspberry pis and assembled setups to image gears.
The processing is done by opencv, it was a great introductory for me to it.
opencv is something I'v always wanted to play with anyhow.
Lots of ideas went back and forth as the project progresssed, some ideas worked
better than others, some silly ideas worked well, some great ideas flopped, 
so it goes!. 
The resulting software is only part of the origional target. This software will
count the teeth, the remainder of the idea was to have the software measure the 
gear and classify its pitch and pressure angles.
Its just a counter and *mostly* works ok. I myself ran about 300+ gears thru
it and am satisifed with the results. I noticed that some of my hand counts
were wrong in the process! 8]
I have also run sprockets and encoder wheels thru it, as they are quite gear-like...

The source code is on github:
   https://github.com/ruenahcmohr/gearcounter