Abstract: An apparatus for detecting a moving ferromagnetic target object in a protected area comprises a first magnetic sensor adapted to measure a magnetic field within a first localised volume of space defined by a first zone of sensitivity of the first magnetic sensor and to produce a corresponding first measurement signal, and a second magnetic sensor adapted to measure a magnetic field within a second localised volume of space defined by a second zone of sensitivity of the second magnetic sensor and to produce a corresponding second measurement signal. The two magnetic sensors are separated spatially by a baseline such that the overlap between the two zones of sensitivity defines both a protected zone and a non-protected zone.

Abstract: An apparatus for detecting a moving ferromagnetic target object in a protected area comprises a first magnetic sensor adapted to measure a magnetic field within a first localised volume of space defined by a first zone of sensitivity of the first magnetic sensor and to produce a corresponding first measurement signal, and a second magnetic sensor adapted to measure a magnetic field within a second localised volume of space defined by a second zone of sensitivity of the second magnetic sensor and to produce a corresponding second measurement signal.The two magnetic sensors are separated spatially by a baseline such that the overlap between the two zones of sensitivity defines both a protected zone and a non-protected zone.

Abstract: A method for determining the elapsed time after discharge of a firearm is disclosed. The method utilizes the change in induced magnetization of a firearm to obtain a value for initial magnetization after discharge of the firearm. This value can then be compared with a magnetic base calibration obtainable through further testing of the magnetization over a period of time. By comparison between the initial magnetization and the base calibration, the time of discharge of the firearm can be estimated. The invention also includes apparatus for use in measuring the magnetization of a firearm, and a kit for implementation of the disclosed method.

Abstract: Apparatus (10) for establishing the positions of metal objects in a mixed input stream of both metal and non-metal objects, the apparatus comprising a differential metal-detecting coil (14A) having a first coil portion wound in a first sense and a second coil portion of generally similar shape and size to the first, wound in a second sense opposite to the first sense, and conveying means (11) for moving objects with respect to, and past, the differential metal-detecting coil in a plane and in a direction with unit vector â, characterised in that the second coil portion is displaced from the first coil portion by a displacement B having a component in the plane in a direction with unit vector {circumflex over (b)}, wherein 0<cos?1 â·{circumflex over (b)}<?/2, and in that the apparatus further comprises analysing means for analysing the form of the output voltage of the coil as a function of time to establish the position of said metal objects in a direction ? in the plane, where ? is defined by â·?=0.