Apparatus and Method for Ferromagnetic Object Detector

摘要

An apparatus is provided for compensating for the effect of a moving door on a nearby ferromagnetic object detector. The ferromagnetic object detector is of a type to produce a main sensor signal indicative of the presence of a ferromagnetic object in the vicinity of the ferromagnetic object detector. Furthermore, the door is arranged relative to the ferromagnetic object detector such that movement of the door is liable to introduce an undesirable interference signal into the main sensor signal. The apparatus comprises an input (3) for receiving the main sensor signal and a door sensor signal that is responsive to an opening angle of the door. The apparatus also comprises an interference signal estimator (4) for estimating a door-related interference signal in dependence upon the door sensor signal and a model of interference for the door. The apparatus also comprises an interference signal canceller (6) for at least partially removing the estimated door-related interference signal from the main sensor signal to produce a compensated sensor signal. The apparatus also comprises an output (5) for outputting the compensated sensor signal.