Millimeter wave imaging method and system to detect concealed objects

• US 8,213,672 B2
• Filed: 08/08/2007
• Issued: 07/03/2012
• Est. Priority Date: 08/08/2007
• Status: Expired due to Fees

• Current Assignee: Microsemi Corporation (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corporation (Microchip Technology Incorporated)
• Inventors: Daly, Robert, Barrantes, Ernesto
• Primary Examiner(s): Mehta, Bhavesh
• Assistant Examiner(s): ANSARI, TAHMINA N
• Application Number:
  US11/835,886
• Publication Number:
  US 20090041292A1
• Time in Patent Office: 1,791 Days
• Field of Search: None
• US Class Current: 382/100
• CPC Class Codes: G01V 8/005 operating with millimetre waves, e.g. measuring the black losey radiation
• CPC Class Codes: H01Q 21/064 using horn or slot aerials slotted waveguides arrays H01Q21/005

Abstract

The invention provides for an expandable multi channel radiometer imaging method and system. The imaging system includes a scanner for reflecting millimeter wave energy emanating from a pre-determined scene. The millimeter wave energy is focused to a focal plane array using an optical lens and a multi channel radiometer receives the millimeter wave energy. The focal plane array is formed by a plurality of pixels that each includes a single low noise amplifier. The number of pixels of the focal plane array is expendable to increase the resolution of a millimeter wave image. A virtual grid of cells is formed representing different values of millimeter wave energy within the imaging zone. Algorithms calculate differences of millimeter wave energy between cells of said virtual grid to display a composite image to identify concealed objects on an individual.

Claims

1. A method of detecting concealed objects on an individual, the method comprising:

scanning an imaging zone of a scene for millimeter wave energy with a scanning apparatus, wherein the scanning apparatus having a reflective concave surface constrained to oscillate in a vertical plane to reflect millimeter wave energy of the imaging zone sequentially;

correlating movement of the reflective concave surface to x-y coordinates in the imaging zone to determine the millimeter wave energy at a specific x-y coordinate of the imaging zone;

focusing the millimeter wave energy using an optical lens;

receiving the millimeter wave energy using a multi channel radiometer;

calculating values for a grid of cells representing the millimeter wave energy received by the multi channel radiometer;

analyzing differences between the values of the millimeter wave energy between the cells of the grid using algorithms;

identifying contrast cells from the grid of cells wherein the contrast cells having values of the millimeter wave energy with a preselected difference between adjacent cells;

forming a discrete image of the contrast cells;

synchronizing the discrete image of the contrast cells with a video image of the imaging zone;

forming a real-time composite image so that the imaging zone is overlaid with the discrete image of the contrast cells; and

displaying the composite image.

2. The method of claim 1, wherein the multi channel radiometer is adaptable for electrically coupling a preselected number of radio frequency (“

RF”

) boards having a plurality of pixels.

3. The method of claim 2 further comprising providing each pixel of the plurality of pixels with a single low noise amplifier.

4. The method of claim 1 further comprising receiving millimeter wave energy between 80 and 100 GHz.

5. The method of claim 1 further comprising scanning the millimeter wave energy at four frames per second.

6. The method of claim 3 further comprising providing each pixel of the plurality of pixels with an RF switch coupled between an antennae and a receiver.

7. The method of claim 1, wherein the multi channel radiometer has sixteen channels.

8. The method of claim 1, wherein the multi channel radiometer has thirty-two channels.

9. The method of claim 1 further comprising synchronizing the discrete image of contrast cells with the video image of the imaging zone to within a preselected tolerance of fifty milliseconds at four frames per second.

10. An expandable multi channel radiometer imaging system for detecting concealed objects on an individual, the system comprising:

a scanning apparatus for scanning an imaging zone of a scene for millimeter wave energy, wherein the scanning apparatus having a reflective concave surface constrained to oscillate in a vertical plane to reflect millimeter wave energy of the imaging zone sequentially;

correlating movement of the reflective concave surface to x-y coordinates in the imaging zone to determine the millimeter wave energy at a specific x-y coordinate of the imaging zone;

an optical lens adaptable for focusing the millimeter wave energy;

a multi channel radiometer having a receiver for receiving the millimeter wave energy;

a means for calculating values for a grid of cells representing millimeter wave energy received by the multi channel radiometer;

means for analyzing differences between the values of the millimeter wave energy between the cells of the grid using algorithms;

means for recognizing and identifying contrast cells from the grid of cells, wherein the contrast cells having values of the millimeter wave energy with a preselected difference between adjacent cells;

means for forming a discrete image of contrast cells;

means for synchronizing the discrete image of contrast cells with a video image of the imaging zone;

means for forming a real-time composite image so that the imaging zone is overlaid with the discrete image of contrast cells; and

means for displaying the composite image.

11. The multi channel radiometer of claim 10 further comprising electrically coupling a preselected number of RF boards, wherein the RF boards further comprise a plurality of pixels.

12. The pixels of claim 11 wherein each pixel of the plurality of pixels having a single low noise amplifier.

13. The millimeter wave energy of claim 10 wherein the millimeter wave energy is between 80 and 100 GHz.

14. The scanning apparatus of claim 10 wherein the millimeter wave energy is scanned at four frames per second.

15. The pixels of claim 12 wherein each pixel of the plurality of pixels having an RF switch coupled between an antennae and a receiver.

16. The multi channel radiometer of claim 10 wherein the multi channel radiometer comprises sixteen channels.

17. The multi channel radiometer of claim 10 wherein the multi channel radiometer comprises thirty-two channels.

18. The means for synchronization of claim 10 wherein the synchronization of the discrete image of contrast cells with the video image of the imaging zone is to within a preselected tolerance of fifty milliseconds at four frames per second.

19. The system of claim 10 further comprising providing a central processing unit for synchronization the discrete image of contrast cells with the video image of the imaging zone.

20. A method of detecting concealed objects on an individual, the method comprising:

a reflective concave surface constrained to oscillate in a vertical plane to reflect millimeter wave energy of an imaging zone sequentially;

correlating movement of the reflective concave surface to specific x-y coordinates in the imaging zone;

receiving the millimeter wave energy;

calculating values for a grid of cells representing the millimeter wave energy;

analyzing differences between the values of the millimeter wave energy between the cells of the grid; and

identifying contrast cells from the grid of cells, wherein the contrast cells having values of the millimeter wave energy with a preselected difference between adjacent cells.