Ultrasonic-based system for detection of metallic security threats containers on cargo

Patent metadata

Field	Value
Publication number	US-10477785-B2
Application number	US-201515509480-A
Country	US
Kind code	B2
Filing date	Oct 21, 2015
Priority date	Oct 21, 2014
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Proactively identifying and interdicting transport of commodities associated with illicit nuclear materials and nuclear weapons shielded by high Z-number materials, such as lead, can help ensure effective nuclear nonproliferation. In an embodiment, a method for imaging an object on a surface includes exciting a surface with ultrasonic excitation from an ultrasonic transmitter having an ultrasonic transducer in contact with the surface. The method further includes imaging, at a processor, a two-dimensional representation of the object acoustically coupled to the surface based on the ultrasonic reflections received at an ultrasonic receiver via a receiving transducer in contact with the surface. This method can complement existing x-ray screening systems to increase the odds of detecting radiological materials.

First claim

What is claimed is:

1. A method for imaging an object on a surface, the method comprising:
exciting a surface with ultrasonic excitation from an ultrasonic transmitter having an ultrasonic transducer in contact with the surface;
moving (i) the surface relative to the ultrasonic transmitter and an ultrasonic receiver or (ii) the ultrasonic transmitter and the ultrasonic receiver relative to the surface; and
imaging, at a processor, a two-dimensional representation of the object acoustically coupled to the surface based on ultrasonic reflections received at the ultrasonic receiver in contact with the surface.

2. The method of claim 1 , wherein the ultrasonic transmitter is an array of ultrasonic transmitters spanning a substantial length of the surface, and wherein the ultrasonic receiver is an array of ultrasonic receivers spanning the substantial length of the surface.

3. The method of claim 1 , further comprising filtering, at the processor, plane waves from the ultrasonic reflections based on (i) time elapsed since exciting the surface and (ii) the size of the surface, the filtering reducing effects of multipath reflections.

4. The method of claim 1 , wherein the surface is an internal surface of a container.

5. The method of claim 1 , wherein exciting the surface with ultrasonic excitation includes exciting the surface sequentially with a range of frequencies, the range of frequencies based on a thickness of the surface and a material of the surface.

6. The method of claim 5 , wherein the surface is associated with an identifier, and further comprising:
based on the identifier, loading representations of a thickness of the surface and a material of the surface; and
automatically determining the range of frequencies based on the loaded representations.

7. The method of claim 1 , wherein the imaging includes calculating displacement of a wave resulting from the transmitted ultrasonic excitation in the frequency domain by performing a Fourier transform of an observation of the ultrasonic reflections the ultrasonic excitation in the time domain.

8. The method of claim 1 , wherein the ultrasonic reflections are received at a plurality of ultrasonic receivers, the plurality of ultrasonic receiver corresponding with the ultrasonic transmitter.

9. The method of claim 1 , further comprising exciting the surface by emitting ultrasonic excitations orthogonal to the surface at a point of contact of a transducer of the ultrasonic transmitter.

10. A system for imaging objects on a surface, the system comprising:
an ultrasonic transmitter having an ultrasonic transducer in contact with a surface configured to excite the surface with ultrasonic excitation;
an ultrasonic receiver in contact with the surface configured to receive ultrasonic reflections of the ultrasonic excitation;
a motion module configured to move (i) the surface or the ultrasonic transmitter and the ultrasonic receiver such that the surface moves relative to the ultrasonic transmitter and the ultrasonic receiver or (ii) the ultrasonic transmitter and the ultrasonic receiver such that the ultrasonic transmitter and the ultrasonic receiver move relative to the surface;
a processor; and
a memory with computer code instructions stored therein, the memory operatively coupled to said processor such that the computer code instructions configure the processor to implement an imaging module configured to image a two-dimensional representation of the object acoustically coupled to the surface based on the received ultrasonic reflections.

11. The system of claim 10 , wherein the ultrasonic transmitter is an array of ultrasonic transmitters spanning a substantial length of the surface, wherein the ultrasonic receiver is an array of ultrasonic receivers spanning the substantial length of the surface.

12. The system of claim 10 , further comprising wherein the processor is further configured to filter plane waves from the ultrasonic reflections based on (i) time elapsed since exciting the surface and (ii) the size of the surface, the filtering reducing effects of multipath reflections.

13. The system of claim 10 , wherein the surface is an internal surface of a container.

14. The system of claim 10 , wherein the ultrasonic transmitter is further configured to excite the surface with ultrasonic excitation by exciting the surface sequentially with a range of frequencies, the range of frequencies being based on a thickness of the surface and a material of the surface.

15. The system of claim 14 , wherein the surface is associated with an identifier, and the processor is further configured to:
based on the identifier, load representations of a thickness of the surface and a material of the surface; and
automatically determine the range of frequencies based on the loaded representations.

16. The system of claim 10 , wherein the processor is further configured to image by calculating displacement of the wave resulting from the transmitted ultrasonic excitation in the frequency domain by performing a Fourier transform of an observation of the ultrasonic reflections of the ultrasonic excitation in the time domain.

17. The system of claim 10 , wherein the ultrasonic receiver includes a plurality of ultrasonic receivers corresponding with the ultrasonic transmitter.

18. The system of claim 10 , wherein the ultrasonic transmitter is further configured to excite the surface by emitting ultrasonic excitations orthogonal to the surface at a point of contact of a transducer of the ultrasonic transmitter.

Assignees

• Univ Northeastern

Inventors

• Martinez-Lorenzo Jose A
• Lopez Yuri Alvarez

Classifications

• G01N2291/2698

  Other discrete objects, e.g. bricks · CPC title

• G01N2291/0427

  Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever · CPC title

• A01G25/16

  Control of watering · CPC title

• A01G9/247

  Watering arrangements · CPC title

• G01N29/0654 Primary

  Imaging · CPC title