Magnetic imager and method
First Claim
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1. A method for detecting a plurality of objects (16a,b) that are spaced apart laterally, the objects being concealed in a matrix (14a,b) comprising:
- applying a bipolar background magnetic field from outside said matrix above a surface thereof across said plurality of objects to immerse said objects therein, said field being applied periodically with static intervals, with each of said objects being effective to locally perturb said applied background field said bipolar background field has a half wavelength substantially equal to the lateral spacing between said objects; and
measuring said perturbations of said background field spatially across said plurality of objects during said static intervals to detect distribution of said perturbations for detecting and locating each of said objects;
at least one of said field applying step and measuring step being varied to distinguish said objects.
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Abstract
A magnetic imager 10 includes a generator 18 for practicing a method of applying a background magnetic field over a concealed object, with the object being effective to locally perturb the background field. The imager 10 also includes a sensor 20 for measuring perturbations of the background field to detect the object. In one embodiment, the background field is applied quasi-statically. And, the magnitude or rate of change of the perturbations may be measured for determining location, size, and/or condition of the object.
52 Citations
18 Claims
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1. A method for detecting a plurality of objects (16a,b) that are spaced apart laterally, the objects being concealed in a matrix (14a,b) comprising:
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applying a bipolar background magnetic field from outside said matrix above a surface thereof across said plurality of objects to immerse said objects therein, said field being applied periodically with static intervals, with each of said objects being effective to locally perturb said applied background field said bipolar background field has a half wavelength substantially equal to the lateral spacing between said objects; and measuring said perturbations of said background field spatially across said plurality of objects during said static intervals to detect distribution of said perturbations for detecting and locating each of said objects; at least one of said field applying step and measuring step being varied to distinguish said objects. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification