| 摘要 |
The present invention relates to a portal monitoring system that uses distributed sensing to detect metallic objects passing through the portal. The system comprises a length of fibre optic (102) comprising an optical fibre (106) mechanically coupled to a material (108) whose physical characteristics vary dependent on the applied magnetic field. The fibre optic (102) is arranged in the vicinity of a portal (200) and a fibre optic interrogator (104) is adapted to provide distributed sensing on the optical fibre to provide measurement data from a plurality of contiguous portions of said optical fibre at each of a plurality of times. A data analyser processes the measurement data to detect signals characteristic of a disturbance in the magnetic field along the optical fibre. The system of the present invention is able to monitor multiple people passing though a portal at the same time and provide an indication of the location of metallic objects within the portal. |
