Reconfigurable reflect-array to realize task-specific compressive sensing in screening applications

Patent metadata

Field	Value
Publication number	US-9970870-B2
Application number	US-201715451160-A
Country	US
Kind code	B2
Filing date	Mar 6, 2017
Priority date	Mar 4, 2016
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A threat detection system having a reconfigurable reflect-array and compressive sensing unit to effectively detect objects that are a threat is presented. A statistical library, having a wide range of threat and non-threat examples and capable of incorporating new examples while being used, is utilized by several optimization algorithms to calculate an optimal illumination pattern for compressive sensing detection. The reflect-array is configured to produce the optimal illumination pattern via a plurality of reflect-array elements. In this way, a plurality of data may be parallel processed, thereby increasing the detection speed and reducing cost.

First claim

What is claimed is:

1. A reflect-array based threat detection system employing compressive sensing to effectively determine whether or not an object is a threat, the system comprising:
(a) a first processor executing a first optimization algorithm using a plurality of samples to generate a plurality of optimized projections;
(b) a library operatively coupled to the first processor, wherein the plurality of optimized projections and the plurality of samples are stored in the library, wherein the library is capable of adaptively increasing an amount of samples by adding a plurality of new measurement results to improve accuracy of threat determination accuracy;
(c) a reflect-array panel emitting a synthesized radiation in a plurality of directions to scan the object, wherein the reflect-array panel comprises a first set of reflect-array elements, wherein each reflect-array element emits the plurality of optimized projections as a radiation pattern in one of the plurality of directions, wherein the synthesized radiation is a collective radiation comprising each radiation pattern emitted by each reflect-array element, wherein an illumination pattern results from the synthesized radiation reflecting off of the object;
(d) one or more detectors configured to collect a plurality of measurements of the illumination pattern; and
(e) a compressive sensing computer, operatively coupled to the one or more detectors, having a second processor configured to execute a compressive sensing optimization algorithm, herein referred to as a second optimization algorithm, wherein the second optimization algorithm processes the plurality of measurements and determines whether the object poses a threat using the plurality of optimized projections as bases of measurement.

2. The system of claim 1 , wherein the plurality of samples comprises objects that pose a threat and objects that do not pose a threat.

3. The system of claim 1 , wherein Principle Component Analysis, Fisher Linear Discriminant Method, Support Vectors Method, Information Optimal Method, or the K-nearest Neighbor Method is employed individually, or in combination, as the first optimization algorithm.

4. The system of claim 1 , wherein Principle Component Analysis, Fisher Linear Discriminant Method, Support Vectors Method, Information Optimal Method, or the K-nearest Neighbor Method is employed individually, or in combination, as the second optimization algorithm.

5. The system of claim 1 , wherein the first set of reflect-array elements comprises devices of any geometric shape having a dielectric and a conductor.

6. The system claim 1 , wherein each reflect-array element, of the first set of reflect-array elements, has a phase controlled by one or more reconfigurable devices.

7. The system of claim 6 , wherein a diode, a microelectromechanical systems device, or any phase changing device comprises each of the one or more reconfigurable devices.

8. The system of claim 6 , wherein the synthesized radiation is determined by the phase of each reflect-array element, wherein the phase is reconfigurable.

9. The system of claim 1 further comprising a lane having a second reflect-array panel emitting a lane synthesized radiation in a set of directions to scan a second object.

10. The system of claim 9 , wherein the second reflect-array panel comprises a second set of reflect-array elements each emitting the plurality of optimized projections as a radiation pattern in a direction, of the set of directions, wherein the lane synthesized radiation is a collective radiation comprising each radiation pattern emitted by each reflect-array element in the second set of reflect-array elements.

11. The system of claim 10 , wherein the second set of reflect-array elements comprises devices of any geometric shape having a dielectric and a conductor.

12. The system of claim 9 , wherein a second illumination pattern is produced when the lane synthesized radiation is reflected off of the second object.

13. The system of claim 9 , wherein the second object is the bottom of human feet.

14. The system of claim 12 , wherein a plurality of measurements of the second illumination pattern is acquired by the one or more detectors and transmitted to the compressive sensing processing computer.

15. The system of claim 14 , wherein the second processor is further configured to execute a third optimization algorithm, wherein the third optimization algorithm processes the plurality of measurements of the second illumination pattern and determines whether the second object poses a threat using the optimized projections as bases of measurement.

16. The system of claim 9 , wherein Principle Component Analysis, Fisher Linear Discriminant Method, Support Vectors Method, Information Optimal Method, or the K-nearest Neighbor Method is employed individually, or in combination, as the third optimization algorithm.

17. The system of claim 9 further comprising a plurality of lanes.

18. The system of claim 1 , wherein the reflect-array panel scans a plurality of objects at one time.

19. The system of claim 1 further comprising a two-sided reflect-array panel configured to scan an object on each side of the two-sided reflect-array panel.

20. A method for reflect-array based threat detection employing compressive sensing to effectively determine whether an object is a threat, the method comprising:
(a) generating a plurality of optimized projections, wherein the plurality optimized projections result from executing a first optimization algorithm, via a first processor, using a plurality of samples as bases of measurement, wherein a library, operatively coupled to the first processor, stores the plurality of optimized projections;
(b) emitting a synthesized radiation in a plurality of directions to scan the object via a reflect-array panel, wherein the reflect-array panel comprises a set of reflect-array elements, wherein each reflect-array element emits the plurality of optimized projections as a radiation pattern in one of the plurality of directions, wherein the synthesized radiation is a collective radiation comprising each radiation pattern emitted by each reflect-array element, wherein an illumination pattern results from the synthesized radiation reflecting off of the object;
(c) collecting a plurality of measurements of the illumination pattern via one or more detectors; and
(d) executing a second optimization algorithm, alternately referred to herein as a compressive sensing optimization algorithm, via a second processor operatively coupled to the one or more detectors,

wherein the compressive sensing optimization algorithm processes the plurality of measurements and determines whether the object poses a threat using the plurality of optimized projections as bases of measurement.

Assignees

• Univ Arizona

Inventors

• Xin Hao
• Liang Min
• Neifeld Mark A
• Harvey Tim

Classifications

• G01N2201/126

  Microprocessor processing · CPC title

• G01N22/00

  Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more (G01N3/00 - G01N17/00, G01N24/00 take precedence) · CPC title

• H03M7/3062

  Compressive sampling or sensing · CPC title

• H03M7/30

  Compression (speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N); Expansion; Suppression of unnecessary data, e.g. redundancy reduction · CPC title

• G01N2201/123

  Conversion circuit · CPC title