Automobile scanning system
First Claim
1. An apparatus for imaging an organic object contained within a metal enclosure, comprising:
- an x-ray source for producing an x-ray beam passing through said metal enclosure;
a first beam filter for creating a low-energy x-ray spectrum;
said first beam filter comprising an atomic element having a high k-edge energy;
a second beam filter for creating a high-energy x-ray spectrum;
a filter exchanger for alternately positioning said first beam filter and said second beam filter within said x-ray beam;
an x-ray detector for measuring an intensity of said x-ray beam exiting said metal enclosure;
a computer for converting a digitally represented signal into a steel suppressed digital image of said metal enclosure, the computer being programmed to;
calibrate the digitally represented signal to correct for multiple thicknesses of iron in the metal enclosure;
calibrate the digitally represented signal to correct for organic materials in the metal enclosure;
and further wherein the steel suppressed digital image is calculated by logarithmic subtraction;
whereby the image of said organic object is isolated from the interference of said metal enclosure.
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Accused Products
Abstract
A dual energy x-ray imaging system searches a moving automobile for concealed objects. Dual energy operation is achieved by operating an x-ray source at a constant potential of 100 KV to 150 KV, and alternately switching between two beam filters. The first filter is an atomic element having a high k-edge energy, such as platinum, gold, mercury, thallium, lead, bismuth, and thorium, thereby providing a low-energy spectrum. The second filter provides a high-energy spectrum through beam hardening. The low and high energy beams passing through the automobile are received by an x-ray detector. These detected signals are processed by a digital computer to create a steel suppressed image through logarithmic subtraction. The intensity of the x-ray beam is adjusted as the reciprocal of the measured automobile speed, thereby achieving a consistent radiation level regardless of the automobile motion. Accordingly, this invention provides images of organic objects concealed within moving automobiles without the detritus effects of overlying steel and automobile movement.
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Citations
16 Claims
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1. An apparatus for imaging an organic object contained within a metal enclosure, comprising:
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an x-ray source for producing an x-ray beam passing through said metal enclosure; a first beam filter for creating a low-energy x-ray spectrum;
said first beam filter comprising an atomic element having a high k-edge energy;a second beam filter for creating a high-energy x-ray spectrum; a filter exchanger for alternately positioning said first beam filter and said second beam filter within said x-ray beam; an x-ray detector for measuring an intensity of said x-ray beam exiting said metal enclosure; a computer for converting a digitally represented signal into a steel suppressed digital image of said metal enclosure, the computer being programmed to; calibrate the digitally represented signal to correct for multiple thicknesses of iron in the metal enclosure; calibrate the digitally represented signal to correct for organic materials in the metal enclosure; and further wherein the steel suppressed digital image is calculated by logarithmic subtraction; whereby the image of said organic object is isolated from the interference of said metal enclosure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus for searching an automobile for security threats, comprising:
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x-ray generating means for penetrating said automobile with x-ray radiation; switching filter means for changing said x-ray radiation between a low-energy spectrum and a high-energy spectrum, wherein said low-energy spectrum is substantially determined by the k-edge energy of a high atomic number element; x-ray detector means for converting the x-ray radiation that penetrates said automobile into a digitally represented signal; a computer for converting said digitally represented signal into a steel suppressed digital image of said automobile, the computer being programmed to; calibrate the digitally represented signal to correct for multiple thicknesses of iron in the automobile; calibrate the digitally represented signal to correct for organic materials in the automobile; and calculate the steel suppressed digital image by logarithmic subtraction. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification