[CamperBob2]

The card-shuffling machine is an obvious vulnerability.

But I'm provisionally calling BS on the "X-ray table." Based on (admittedly limited) experience with X-ray imaging, I don't believe that X-rays can read ink on playing cards. It would have to be a backscatter machine, which is even less discriminatory than a transmissive machine. Would need to see some evidence that this is possible.

If nothing else, the sheer size and bulk of such a machine renders the concept incredible. If I could build something like that, I wouldn't use it to cheat at cards, I'd sell it to the TSA!

[sigmar]

Couldn't the cards have x-ray opaque ink (like with bismuth trioxide)?

[CamperBob2]

That could be a good point, I suppose. Iron-based ink could have a similar effect. I'll have to see if there's a deck of cards around here to X-ray.

[BertoldVdb]

We tried this long ago at a university, the cards we had were entirely invisible to the x-ray.

I think the 'x-ray' table in the article works with IR cameras and illuminators under the table, and tablecloth that is slightly IR transparent.