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The touchscreen uses diffuse illumination in which a layer of material on the front of the screen is used to reflect infrared light.
There are six optical motion-capture and motion-tracking cameras and 16 infrared illuminators - with a total of more than 1,000 infrared LEDs - located behind the screen.
The cameras are unable to see through the diffuse layer, and when people touch the front of the screen, the infrared light reflected back shows the computer system where the screen is being touched.
Photo: University of Groningen