Multiple wavelength microwave-enhanced infrared thermography
First Claim
1. A method for detecting whether an object is buried beneath a target surface area of the ground, comprising:
- 1) in a first cycle;
a) capturing a first infrared image of the target surface area indicative of a first initial temperature distribution thereon;
b) directing a microwave signal of a first frequency at the target surface area and capturing a second infrared image of the target surface area indicative of a first heated temperature distribution thereon; and
c) subtracting the first infrared image from the second infrared image to form a first temperature rise image;
2) in a second cycle;
a) directing a microwave signal of a second frequency at the target surface area and capturing a third infrared image of the target surface area indicative of a second heated temperature distribution thereon, the second frequency differing from the first frequency by an amount effective to yield an acceptably high signal to noise ratio in a difference image to be calculated as part of the method; and
b) subtracting a fourth infrared image from the third infrared image to form a second temperature rise image, the fourth infrared image being indicative of a second initial temperature distribution of the target surface area at the beginning of the second cycle; and
3) subtracting the first temperature rise image from the second temperature rise image to obtain the difference image for processing to identify characteristics indicative of the presence of a buried object.
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Accused Products
Abstract
A microwave-enhanced infrared thermography technique for detecting buried objects exploits varying phase shifts experienced by different-frequency microwave signals reflected from objects back toward the surface, the phase shifts resulting in different interference patterns and therefore different temperature distribution patterns near the surface. Respective infrared images of an area are captured prior to microwave heating, after a first heating with a first frequency, and after heating with a second frequency different from the first. Pairs of the images are subtracted to form temperature rise images showing patterns of temperature rise in the two cycles, and the temperature rise images are subtracted to form a difference image which is analyzed to identify characteristics indicating the presence of buried objects.
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Citations
6 Claims
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1. A method for detecting whether an object is buried beneath a target surface area of the ground, comprising:
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1) in a first cycle;
a) capturing a first infrared image of the target surface area indicative of a first initial temperature distribution thereon;
b) directing a microwave signal of a first frequency at the target surface area and capturing a second infrared image of the target surface area indicative of a first heated temperature distribution thereon; and
c) subtracting the first infrared image from the second infrared image to form a first temperature rise image;
2) in a second cycle;
a) directing a microwave signal of a second frequency at the target surface area and capturing a third infrared image of the target surface area indicative of a second heated temperature distribution thereon, the second frequency differing from the first frequency by an amount effective to yield an acceptably high signal to noise ratio in a difference image to be calculated as part of the method; and
b) subtracting a fourth infrared image from the third infrared image to form a second temperature rise image, the fourth infrared image being indicative of a second initial temperature distribution of the target surface area at the beginning of the second cycle; and
3) subtracting the first temperature rise image from the second temperature rise image to obtain the difference image for processing to identify characteristics indicative of the presence of a buried object. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification