touch_operation_3Absolute tracking more than one event can be facilitated introducing additional sensors into the system. This can be seen in the Figure below where two additional sensors are added in the lower two corners and the Active-barrier® illumination is extended along the upper side of the panel.

touch_operation_4This four sensor system can easily resolve the two touch of the previous example and can be extended to track a minimum of four and in most cases up to six, touches with absolute accuracy. A sophisticated algorithm can uniquely determine the absolute position of multiple objects despite occlusion or object coalescence in some of the views.