TOUCH DETERMINATION WITH INTERACTION COMPENSATION

摘要

A device implements a data processing method for an optical FTIR-based touch system. The touch system defines detection lines across a surface portion of a panel by propagating light inside the panel from a plurality of incoupling points to a plurality of outcoupling points, such that each location on the surface portion is illuminated by incident light rays. At least one light detector is coupled to the outcoupling points to generate an output signal. The device obtains (50) signal values for the detection lines from the output signal and processes (52) the signal values to at least partly compensate for variations in the apparent interaction among the subset of detection lines that interact with an object on the surface portion. The device uses compensation data which is obtained to at least partly represent the variations that are caused by differences in incident power distribution among the subset of detection lines, the incident power distribution being a distribution of power among the incident light rays on the respective detection line with respect to a normal direction of the surface portion.