A touch system is described having a method of determining touch of one or more objects on a touch surface of a touch-sensitive apparatus, wherein the method operates in a time sequence of frames, each frame comprising the steps of: for a current frame, processing an output signal of the touch sensitive apparatus to generate one or more touch traces, each touch trace having one or more characteristics; and outputting a confirmed touch signal for each touch trace having a touch trace matching at least one of said one or more characteristics in a first number of frames preceding the current frame, wherein the first number of frames is determined in dependence on said one or more characteristics.