Retrieval of 3D-position of a passive object using infrared LEDs and photodiodes

A sensor using infrared emitter/receiver pairs to determine the position of a passive object is presented. An array with a small number of infrared emitter/receiver pairs is proposed as the sensing part to acquire information on the object position. The emitters illuminate the object and the intensity of the light reflected by the object is measured by the receivers. The emitter/receiver pair positions are fixed in a 2D-plane. A model of the light reflections from IR-emitters to IR-receivers is used to determine the position of a ball using a Nelder-Mead simplex algorithm. Laboratory experiments show good agreement between actual and retrieved positions when tracking a ball. The ball has been successfully replaced by a human hand, and a "3D non-touch screen" with a human hand as "pointing device" is shown possible.