Abstract: Authentication apparatus (1, 100) and methods which authenticate an item (4, 110) responsive to the detection that a portion of the item has one or more predetermined characteristics, the said predetermined characteristics comprising either or both the thickness of the said portion of the item, and the thickness of one or more layers within the said portion of the item, determined by optically-based thickness measuring apparatus (6, 102-108). The item may be a product and the portion of the item may be a sheet of packaging material. The item may be a security document and the portion of the item may be a sheet of security document substrate.

Abstract: Authentication apparatus (1, 100) and methods which authenticate an item (4, 110) responsive to the detection that a portion of the item has one or more predetermined characteristics, the said predetermined characteristics comprising either or both the thickness of the said portion of the item, and the thickness of one or more layers within the said portion of the item, determined by optically-based thickness measuring apparatus (6, 102-108). The item may be a product and the portion of the item may be a sheet of packaging material. The item may be a security document and the portion of the item may be a sheet of security document substrate.

Abstract: Authentication apparatus (1, 100) and methods which authenticate an item (4, 110) responsive to the detection that a portion of the item has one or more predetermined characteristics, the said predetermined characteristics comprising either or both the thickness of the said portion of the item, and the thickness of one or more layers within the said portion of the item, determined by optically-based thickness measuring apparatus (6, 102-108). The item may be a product and the portion of the item may be a sheet of packaging material. The item may be a security document and the portion of the item may be a sheet of security document substrate.

Abstract: An optical monitoring system includes a sensor network including a plurality of optical sensors. The optical switch module is disposed on a first side of a pressure barrier, coupled to the sensor network, and operable to select various subsets of the optical sensors responsive to a control signal. The sensor interrogation unit is disposed on a second side of the pressure barrier and operable to generate the control signal and receive an optical signal from a particular subset of the sensor elements selected by the optical switch module. The optical penetrator is coupled to the interrogation unit and the optical switch module and operable to communicate the optical signal through the pressure barrier. The inductive control unit is operable to inductively communicate the control signal and a power signal to the optical switch module through the pressure barrier.

Abstract: Authentication apparatus (1, 100) and methods which authenticate an item (4, 110) responsive to the detection that a portion of the item has one or more predetermined characteristics, the said predetermined characteristics comprising either or both the thickness of the said portion of the item, and the thickness of one or more layers within the said portion of the item, determined by optically-based thickness measuring apparatus (6, 102-108). The item may be a product and the portion of the item may be a sheet of packaging material. The item may be a security document and the portion of the item may be a sheet of security document substrate.