Abstract: A magnetic screening system uses directional gradiometers with high resolution and accuracy to measure magnetic field signatures of target objects (e.g., gun, knife, cell phone, keys) in a volume of interest. The measured signatures can be compared to signatures of known objects stored in a local database. Various mathematical processes may be used to identify or classify target object signatures. A magnetic screening system network according to embodiments of the present invention includes gradiometers, gradiometer processors, screening computers, and a management computer. The gradiometers sense target objects in a subject volume and the gradiometer processors process data obtained from the gradiometers. The screening computers process data output of the gradiometer processors and maintain local databases of signatures associated with known target objects.

Abstract: A magnetic screening system uses directional gradiometers with high resolution and accuracy to measure magnetic field signatures of target objects (e.g., gun, knife, cell phone, keys) in a volume of interest. The measured signatures can be compared to signatures of known objects stored in a local database. Various mathematical processes may be used to identify or classify target object signatures. In a network of magnetic screening systems, the magnetic screening systems can transmit signatures to a central signature database, and a management computer can share the central signature database with all of the magnetic screening systems on the network. The magnetic screening system can operate in multiple modes, such as a tracking mode, measurement mode, calibration mode, and self-test mode. Calibration may be performed in a substantially continuous manner to allow calibration parameters to be adjusted during system operation (e.g.