Millimeter wave imaging method and system to detect concealed objects

• US 8,712,093 B2
• Filed: 07/02/2012
• Issued: 04/29/2014
• 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): ANSARI, TAHMINA N
• Application Number:
  US13/540,340
• Publication Number:
  US 20120288137A1
• Time in Patent Office: 666 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 for millimeter wave energy radiating therefrom using a system having a reflective surface configured to oscillate, said oscillating reflective surface arranged to sequentially reflect the millimeter wave energy radiating from the imaging zone to an array of pixels through an optical lens;

correlating movement of the oscillating reflective surface to coordinates in the imaging zone to determine the millimeter wave energy at specific coordinates of the imaging zone;

receiving the reflected millimeter wave energy at the array of pixels;

calculating values for a grid of cells, the value of each cell representing the reflected millimeter wave energy received at one pixel of the array of pixels;

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

identifying contrast cells from the grid of cells, the contrast cells having values of the reflected millimeter wave energy with a predetermined difference between adjacent cells;

forming a discrete image of the contrast cells;

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

generating a real-time composite image so that the specific coordinates of the video image of the imaging zone are overlaid with corresponding cells in the discrete image of the contrast cells; and

displaying said composite image.

2. The method of claim 1, wherein said receiving the reflected millimeter wave energy comprises receiving the reflected millimeter wave energy using a multi-channel radiometer.

3. The method of claim 1, wherein said scanning for millimeter wave energy comprises scanning for millimeter wave energy between 80 and 100 GHz.

4. An imaging apparatus, comprising:

a video imaging system configured to obtain a video image of an imaging zone;

a scanner having a reflecting surface and an optical lens;

a multi-channel radiometer comprising an array of pixels and coupled with the scanner;

a processor coupled with the video imaging system, the scanner, and the multi-channel radiometer; and

a monitor coupled with the processor;

said scanner reflective surface configured to oscillate, said oscillating reflective surface arranged to sequentially reflect received millimeter wave energy radiating from a portion of the imaging zone to the array of pixels of said multi-channel radiometer through the optical lens,

said processor configured to;

correlate movement of the reflective surface in the scanner to coordinates in the imaging zone so as to determine the millimeter wave energy at specific coordinates of the imaging zone;

calculate values for a grid of cells, the value of each cell representing millimeter wave energy received by one pixel of the array of pixels in the multi-channel radiometer;

identify contrast cells from the grid of cells, the contrast cells identified as adjacent cells having values of the millimeter wave energy with a predetermined difference;

form a discrete image of the identified contrast cells;

synchronize the discrete image of contrast cells with the video image of the imaging zone;

generate a composite image of the video image overlaid with the discrete image of contrast cells such that the specific coordinates of the video image of the imaging zone are overlaid with corresponding cells in the discrete image of the contrast cells; and

display the composite image on said monitor.

5. The apparatus of claim 4, wherein the composite image is a real-time composite image.

6. The apparatus of claim 4, wherein the multi-channel radiometer comprises a radio frequency (RF) board electrically coupled to each pixel of the array of pixels.

7. The apparatus of claim 6, wherein the multi-channel radiometer further comprises a plurality of low noise amplifiers each associated with a respective pixel.

8. The apparatus of claim 6, wherein the multi-channel radiometer further comprises a plurality of RF switches each coupled between an antennae and a receiver of the respective pixel.

9. The apparatus of claim 4, wherein the millimeter wave energy is between 80 and 100 GHz.