Time of flight backscatter imaging system
First Claim
1. An X-ray imaging apparatus for determining a surface profile of an object under inspection and positioned at a distance from said apparatus, comprising:
- an X-ray source for producing a scanning beam of X-rays directed toward said object;
a detector assembly adapted to provide a signal representative of an intensity of X-rays backscattered from said object; and
processing circuitry adapted to determine a time difference between when the X-ray source is switched on and when the backscattered X-rays arrive at the detector assembly and adapted to output data representative of the surface profile of the object under inspection, wherein said processing circuitry comprises a comparator capacitor adapted to be charged by a current source when said X-ray source is turned on, a switch that disconnects said comparator capacitor from the current source when a voltage of the comparator capacitor equals or exceeds a reference voltage, an analog to digital converter to generate a digital value representative of said voltage, and circuitry to determine said time difference from said digital value.
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Accused Products
Abstract
The present application discloses an X-ray imaging apparatus for determining a surface profile of an object under inspection that is positioned at a distance from the apparatus. The X-ray imaging system has an X-ray source for producing a scanning beam of X-rays directed toward the object, a detector assembly for providing a signal representative of an intensity of X-rays backscattered from the object, and processing circuitry to determine a time difference between when the X-ray source is switched on and when the backscattered X-rays arrive at the detector assembly. The processing circuitry is adapted to output data representative of the surface profile of the object under inspection.
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Citations
20 Claims
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1. An X-ray imaging apparatus for determining a surface profile of an object under inspection and positioned at a distance from said apparatus, comprising:
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an X-ray source for producing a scanning beam of X-rays directed toward said object; a detector assembly adapted to provide a signal representative of an intensity of X-rays backscattered from said object; and processing circuitry adapted to determine a time difference between when the X-ray source is switched on and when the backscattered X-rays arrive at the detector assembly and adapted to output data representative of the surface profile of the object under inspection, wherein said processing circuitry comprises a comparator capacitor adapted to be charged by a current source when said X-ray source is turned on, a switch that disconnects said comparator capacitor from the current source when a voltage of the comparator capacitor equals or exceeds a reference voltage, an analog to digital converter to generate a digital value representative of said voltage, and circuitry to determine said time difference from said digital value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An X-ray imaging apparatus for determining the presence and location of a threat beneath an exterior surface of an object under inspection, comprising:
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an X-ray source for producing a scanning pencil beam of X-rays directed toward said object; a detector assembly adapted to provide a first signal representative of an intensity of the X-rays backscattered from said exterior surface of the object under inspection and a second signal representative of an intensity of the X-rays backscattered from said threat beneath the exterior surface of the object under inspection; and processing circuitry adapted to determine a first time difference between when the X-ray source is switched on and when the X-rays backscattered from the exterior surface of the object under inspection arrive at the detector assembly and a second time difference between when the X-ray source is switched on and when the X-rays backscattered from the threat beneath the exterior surface of the object under inspection arrive at the detector assembly and adapted to output data representative of a surface profile of the object under inspection based upon at least one of said first time difference or second time difference, wherein said processing circuitry comprises a comparator capacitor adapted to be charged by a current source when said X-ray source is turned on, a switch that disconnects said comparator capacitor from the current source when a voltage of the comparator capacitor equals or exceeds a reference voltage, an analog to digital converter to generate a digital value representative of said voltage, and circuitry to determine said first or second time difference from said digital value. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for determining a surface profile of an object under inspection, said method comprising the steps of:
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positioning an object under inspection at a distance from an X-ray imaging apparatus, wherein said X-ray imaging apparatus comprises an X-ray source and a detector array; operating said X-ray source to produce a scanning pencil beam of X-rays directed toward said object; detecting a signal representative of an intensity of the X-rays backscattered from said object, using said detector array; determining a time difference between when the X-ray source is switched on and when the backscattered signal is detected using processing circuitry, wherein said processing circuitry comprises a comparator capacitor adapted to be charged by a current source when said X-ray source is turned on, a switch that disconnects said comparator capacitor from the current source when a voltage of the comparator capacitor equals or exceeds a reference voltage, an analog to digital converter to generate a digital value representative of said voltage, and circuitry to determine said time difference from said digital value; and outputting data representative of the surface profile of the object under inspection. - View Dependent Claims (18, 19, 20)
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Specification