> Bear in mind you only get to record cards that are shown, so it could potentially take many games to record the full deck, and that's assuming the deck stays

> Bear in mind you only get to record cards that are shown, so it could potentially take many games to record the full deck, and that's assuming the deck stays consistent. Depending on what game you are playing, you don't need to mark anywhere near the full deck. In hold'em, you can get a definite edge if you manage to mark two aces. The primary problem is optics. All optical devices are limited by the quantization of light. No matter how good your camera technology, if there are not enough photons bouncing off a target, you cannot see it accurately. Modern cameras (and even your eyes!) are much closer to the hard limits placed by physics than most people think. In the case of a side of a card in not very well lit indoors, I don't think you can discern enough detail without either a large lens or a long exposure, both of which could be hard to pull off inside a casino. Even painted on markings, they need a bright IR light to pull this off at a close distance. Similarly, your camera would need a bright light source.