US Patent 8130097 Card and chip detection system for a gaming table

A card and detection system comprises a group of light sensors located under and covered over by a table felt. The light sensors are directed vertically upward to detect changes in light intensity on the top surfaces of the sensors through the felt. This allows flexibility of placement of the sensors and avoids daily maintenance issues. The sensors read through fabric to detect when objects such as chips or cards are placed on top of the felt. With this system, the procedure of detecting chips or cards is imperceptible to the customers or dealers.