Part I: Card Game Cheating · Collusion & Electronic Cheating at Card Games · #2.31
Infrared Marked Cards with Contact Lenses
How it works
Playing cards are marked on the backs with invisible infrared ink that is completely invisible to the naked eye and standard cameras (which have IR-cut filters). The cheater wears special contact lenses or glasses with infrared band-pass filters that make the markings glow clearly, allowing them to read card values without any visible indication of cheating. The lenses carry a filter that makes the ink visible and they can pass for slightly tinted contact lenses that appears as a slightly tinted contact lens but is hard to detect in normal conditions. The system emits no electronic signals, making it completely invisible to RF detectors.
Where it appears
Poker, blackjack, baccarat, any card game
On the record
Infrared marked cards have been used in gambling fraud for decades. In 2013, a court in Grasse sentenced Stefano Ampollini to two years in prison for using infrared contact lenses and marked cards at stud poker in a Cannes casino; he and an accomplice took €70,000 on one visit and he won €21,000 on another. PubMed has published research on detecting invisible ink markings using image processing techniques.
Detection & preventionADVISORY
The paid halfHow a monitoring room catches infrared marked cards with contact lenses, and what stops it recurring, written for the desk, not the reader.
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Published as a detection reference for surveillance, compliance and gaming-operations professionals. Thresholds and tuning are set by the property. Nothing here is instruction: the method is described so it can be recognised.