Optical sensor based on pseudo-random diffractive optical elements for reliable gesture reconstruction

The concept, design guidelines and reconstruction results for a universal gesture-based optical remote control with simple quasi-intuitive operation are presented. The buttonless hand-held flashlight-type device emits "structured" infrared light with a pseudo-random spatial pattern projected by a diffractive optical element (DOE). A cost-effective array of photodetectors on or near the device to be remotely controlled records the spatio-temporal intensity changes while a gesture is carried out. From the consecutive time lags between highly correlated signal segments received at each pair of photodetectors, the velocity vector is composed from which Cartesian coordinates of the trajectory of motion of the pattern are calculated and the gesture is reconstructed. Extensive simulations varying major design parameters of the DOE pattern and the receiver array were carried out. Based on simulated and typical practical gestures obtained from user tests, design parameters for a highly satisfactory reconstruction performance could be identified.