The basic (read as "affordable") machine that just about every poker room uses does not have a camera that can read the cards. That would be cost prohibitive. These machines also do not shuffle the cards, they sort them. The computer randomly creates a list from 1 to 52 (this top number is programmable to accommodate decks of varying sizes). For example 4, 32, 41, 9, etc. In this example, when the deck goes into the machine it will take the 4th card and make it the 1st card, then the 32nd card and make it the 2nd card, then the 41st card and make it the 3rd card, etc. until all 52 cards are sorted into the new random order. That's why it takes so long for the machine to finish the "shuffle". If it were just performing 3 riffles, 1 stripe, 1 riffle, and then 1 cut, as dealers do when they hand shuffle, it would be much speedier.

Their more expensive models do have cameras and do scan each card before sorting them (either randomly or in a set order). This type machine is usually found at house games, like 3 Card Poker or Caribbean Stud. Since the house would not have any patrons, and not make any money, if they fixed the decks in their favor, even just a tiny bit, the random shuffle is what they use. They'd be stupid to do otherwise.

When poker players call for a new set-up, the old decks are re-ordered and re-used. The staff will often times use the more expensive machines at empty tables to do this for them. They hit a button telling the machine to sort the cards in order, ranks then suits, and it gets done perfectly in a matter of seconds.