1. A device comprising: a controller; a memory coupled to the controller; and an input interface arranged to received at least two event signals, wherein the controller is arranged to determine an estimated value of at least one of the at least two event signals using a transform function and at least the other of the at least two event signals, and to determine a deviation between the estimated event signal and the at leat one event signal, and to determine whether an artifact is present in the at least one event signal in accordance with the deviation.