Abstract: An apparatus for detecting the presence of multiple items includes a platform upon which one or more items may be placed and a detector positioned with respect to the platform to receive an image of a profile of the one or more items on the platform. The detector is configured and arranged to generate a signal corresponding to the profile. The signal indicates whether multiple items are on the platform. The detector may be, for example, a moving point detector, a linear detector, or a two-dimensional array detector. This apparatus can be used in conjunction with an inventory control device, such as an automated library check-out device, to prevent the unauthorized removal of inventory items.

Abstract: An electronic article surveillance (EAS) systems includes an asynchronous noise suppression adaptive filter which removes asynchronous interference from the signal of interest with minimum distortion of the transients emitted when a sensitized tag is interrogated. The system also includes a synchronous noise suppression filter which removes interrogation synchronous noise from the signal of interest. The resulting EAS system increases the likelihood that a sensitized tag will be detected when one is present and reduces the occurrence of false alarms.