This idea would be for a high-speed coin sorter augmented by a digital camera and high-speed image processing aparatus. Coins would be dumped into a hopper and sorted in the usual fashion, but the camera would photograph each coin as it went through (preferably both sides, using mirrors). In addition to examining the photographs to add a certain level of counterfeit-detection ability, the unit could also examine things like dates or designs to determine if a coin was collectable.

If practical, it would be desirable to have the image analysis done real time. If this did not prove to be practical, depending upon the lag time involved, it might be possible to use queueing chutes to keep the last few dozen or hundred coins of any particular denomination separate from the rest; even if the machine couldn't pop out a rare mis-struck quarter in real time, it could flag the user that the coin was somewhere in the queueing chute.

I don't know exactly what current imaging technologies allow, but it would seem like this idea might be feasible. The biggest problem I can see is that if such devices became at all common the number of rare coins in circulation could plumet (perhaps this belongs in Public: Evil?)
-- supercat, Dec 04 2004

Dime weights http://www.sammler....roosevelt_dimes.htm
[bungston, Dec 04 2004]

This method could find the really rare coins, but would miss the less rare silver versions of currently used coins. It occurs to me, though, that you could do the same thing witha careful scale and sort the coins out by weight. An even faster way to do the same thing would be to weigh entire rolls. A roll of prosaic modern dimes should weigh a certain amount. Deviation from this amount would suggest that there might be a silver dime in there, and the roll should be set aside for closer analysis. Probably this would wind up netting a boatload of canadian dimes, though.
-- bungston, Dec 04 2004


I didn’t have the patience to become a *real* coin collector, but I learned a bit about it. Since I don’t spend change directly, it accumulates and I bring it to a counting / sorting machine. There is a percentage charge for this which I’m happy to pay so I don’t have to count / wrap them myself. The thought that I may be dumping higher than face-value coins ‘down the drain’ does bother me a little, so I would use this. +

As for it being evil, I disagree. If this machine sat next to a typical machine and charged more for the service, it would be used far less, and mostly by pseudo-collectors such as myself.

I’m not sure if imaging technology is advanced enough for this application, but another + for counterfeit detection anyhow. There’s a minted coin out there that’s a working slug for a US quarter.
-- Shz, Dec 05 2004


I believe modern 'slug' coins were designed to weigh almost exactly the same amount as their silver counterparts, since many coin-accepting machines were designed to accept the former. Image analysis should make it easy to identify the silver ones, though, since I think they had different date ranges from the 'slug' ones. There may have been some years in which multiple types of coins were used, but even if so, pulling out all coins from that year for hand-inspection would not seem excessive.
-- supercat, Dec 05 2004


I am sure you are right about the slugs. Perhaps this could be done using electrical conductivity. Older pure copperand silver (and gold! Gold!) coins would me more conductive that current alloys.

This would not work for more recent vintages. I understand that conductivity is used in current coin op machines. One of the problems with the sacajawea dollar is that it had to have the same conductivity as the metal used in the Anthony dollar, but be gold.
-- bungston, Nov 25 2005



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