Radar imaging system and method using gradient magnitude second moment spatial variance detection

• US 20100283668A1
• Filed: 10/18/2007
• Published: 11/11/2010
• Est. Priority Date: 10/26/2006
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Bruyere, Donald, Treece, John, Ashcraft, Ivan
• Granted Patent: US 8,054,217 B2
• Time in Patent Office: Days
• US Class Current: 342/25A
• CPC Class Codes: G01S 13/9004 SAR image acquisition techniques
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence

Abstract

A detection system and method. The inventive system includes an arrangement for receiving a frame of image data; an arrangement for performing a rate of change of variance calculation with respect to at least one pixel in said frame of image data; and an arrangement for comparing said calculated rate of change of variance with a predetermined threshold to provide output data. In the illustrative embodiment, the frame of image data includes a range/Doppler matrix of N down range samples and M cross range samples. In this embodiment, the arrangement for performing a rate of change of variance calculation includes an arrangement for calculating a rate of change of variance over an N×M window within the range/Doppler matrix. The arrangement for performing a rate of change of variance calculation includes an arrangement for identifying a change in a standard deviation of a small, localized sampling of cells. In accordance with the invention, the arrangement for performing a rate of change of variance calculation outputs a rate of change of variance pixel map.

Claims

1. A detection system comprising:

means for receiving a frame of image data;

means for performing a rate of change of variance calculation with respect to at least one pixel in said frame of image data; and

means for comparing said calculated rate of change of variance with a predetermined threshold to provide output data.

2. The invention of claim 1 wherein said frame of image data includes a range/Doppler matrix.

3. The invention of claim 2 wherein said range/Doppler matrix includes N down range samples and M cross range samples.

4. The invention of claim 2 wherein said means for performing a rate of change of variance calculation includes means for calculating a rate of change of variance over an N×

M window within said range/Doppler matrix.

5. The invention of claim 4 wherein said means for performing a rate of change of variance calculation outputs a rate of change of variance pixel map.

6. The invention of claim 1 wherein said means for performing a rate of change of variance calculation includes means for identifying a change in a standard deviation of a small, localized sampling of cells.

7. A radar system comprising:

a radar antenna;

a transmitter;

a receiver;

circulator means for coupling said transmitter and receiver to said antenna;

an image processor coupled to said receiver; and

a detection processor coupled to said image processor, said detection processor having;

software for receiving a frame of image data;

software for performing a rate of change of variance calculation with respect to at least one pixel in said frame of image data; and

software for comparing said calculated rate of change of variance with a predetermined threshold to provide output data.

8. The invention of claim 7 wherein said frame of image data includes a range/Doppler matrix.

9. The invention of claim 8 wherein said range/Doppler matrix includes N down range samples and M cross range samples.

10. The invention of claim 8 wherein said software for performing a rate of change of variance calculation includes software for calculating a rate of change of variance over an N×

M window within said range/Doppler matrix.

11. The invention of claim 10 wherein said software for performing a rate of change of variance calculation outputs a rate of change of variance pixel map.

12. The invention of claim 7 wherein said software for performing a rate of change of variance calculation includes software for identifying a change in a standard deviation of a small, localized sampling of cells.

13. The invention of claim 7 further including a track processor.

14. A detection method comprising the steps of:

receiving a frame of image data;

performing a rate of change of variance calculation with respect to at least one pixel in said frame of image data; and

comparing said calculated rate of change of variance with a predetermined threshold to provide output data.