Method and system for rendering a synthetic aperture radar image

• US 9,709,673 B2
• Filed: 04/14/2014
• Issued: 07/18/2017
• Est. Priority Date: 04/14/2014
• Status: Active Grant

• Current Assignee: Maxar International Sweden AB (Galileo Parent, Inc.)
• Original Assignee: Saab Vricon Systems AB
• Inventors: Toss, Tomas, Dammert, Patrik, Carlbom, Per, Haglund, Leif
• Primary Examiner(s): BYTHROW, PETER M
• Application Number:
  US14/363,267
• Publication Number:
  US 20160259046A1
• Time in Patent Office: 1,191 Days
• Field of Search: 342 25 A
• CPC Class Codes: G01S 13/9027 Pattern recognition for feature extraction
• CPC Class Codes: G01S 13/9094 Theoretical aspects
• CPC Class Codes: G06T 15/00 3D [Three Dimensional] image rendering
• CPC Class Codes: G06T 15/20 Perspective computation
• CPC Class Codes: G06T 17/05 Geographic models

Abstract

The present disclosure relates to a method (100) for rendering a simulated Synthetic Aperture Radar, SAR, image. The method comprises providing (110) a digital surface model or the like comprising 3D coordinate data in a geo-referenced coordinate system, determining (120) a sub-section of the digital surface model, and obtaining (130) the simulated SAR image based on the subsection of the digital surface model, wherein substantially each point in the simulated SAR image being associated to a 3D coordinate in the geo-referenced coordinate system.

Claims

1. Method (100;

200) for rendering a simulated Synthetic Aperture Radar (SAR) image, said method comprising the steps of;

providing (110) a digital model comprising 3D coordinate data in a geo-referenced coordinate system;

determining (120) a sub-section of the digital model; and

rendering (130) the simulated SAR image based on the subsection of the digital model, wherein substantially each point in the simulated SAR image being associated to a three-dimensional (3D) coordinate in the geo-referenced coordinate system.

2. Method according to claim 1, wherein the determination (120) of the sub-section of the digital model is based on a geo-referenced coordinate data input.

3. Method according to claim 1, wherein the geo-referenced coordinate data input is continuously updated.

4. Method according to claim 1, wherein the step of obtaining (130) the simulated SAR image comprises performing transformation of the subsection of the digital model.

5. Method according to claim 1, wherein the step of obtaining (130) the simulated SAR image comprises:

simulating back-scatter in the digital model from the simulated aperture; and

obtaining the simulated SAR image based on a distribution of the simulated back-scatter.

6. Method according to claim 1, further comprising steps of:

obtaining (205) a sensor image;

matching (240) the sensor image and the simulated SAR image; and

transferring (243) for at least one of the points in the simulated SAR image the associated coordinate in the geo-referenced coordinate system to a corresponding point in the sensor image.

7. Method according to claim 6, wherein at least a subset of the 3D coordinates of the digital model are associated to an attribute and wherein the step of matching (240) the sensor image and the simulated SAR image is based on the attribute.

8. Method according to claim 6, wherein the determination (120) of the sub-section of the digital model is performed based on an estimation of a position of a sensor capturing the sensor image and an estimated vector to the ground.

9. Method according to claim 6, further comprising a step of estimating (215) the position of the sensor and the estimated vector to the ground, wherein the estimation is based on position related information from a GPS receiver and/or inertial navigation system.

10. Method according to claim 6, further comprising a step of comparing (245) the matched simulated SAR image and the SAR image to determine at least one difference value.

23. A computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising at least one executable portion configured for executing the steps of the method according to claim 1.

11. System (900;

1000) for rendering a simulated Synthetic Aperture Radar (SAR) image, said system comprising;

a digital model store (965;

1065) configured to store a digital model or the like comprising three-dimensional (3D) coordinate data in a geo-referenced coordinate system; and

a first processing element (962;

1062) configured to render the simulated SAR image based on a subsection of the digital model,

wherein substantially each point in the simulated SAR image is associated to a coordinate in the geo-referenced coordinate system.

12. System according to claim 11, further comprising a presentation unit (963;

1063) configured to present information related to the simulated SAR image.

13. A system according to claim 11, further comprising a user interface (961;

1061) configured to receive user input identifying the subsection of the digital model.

14. A system according to claim 13, wherein the user interface (1061) is configured to receive user input related to a position or track of the simulated SAR.

15. A system according to claim 14, wherein the position or track of the simulated SAR is given in the geo-referenced coordinate system.

16. A system according to claim 11, wherein the first processing element (962;

1062) is configured to simulate back-scatter in the digital model from the simulated aperture and to determine the simulated SAR image based on a distribution of the simulated back-scatter.

17. A system according to claim 11, further comprising:

a sensor (1066) arranged to obtain a SAR image;

a second processing element (1068) configured to match the sensor image and the simulated SAR image; and

a third processing element (1070) configured to transfer, for at least one of the points in the simulated SAR image, the associated coordinate in the geo-referenced coordinate system to a corresponding point in the sensor image.

18. A system according to claim 17, wherein the digital model store (1065) is arranged to store for at least a subset of the 3D coordinates of the digital model, at least one attribute associated to the corresponding 3D coordinate, and wherein the second processing element (1068) is arranged to match the sensor image and the simulated SAR image based on the attribute.

19. A system according to claim 17, further comprising a fourth processing element (1071) configured to compare the matched simulated SAR image and the SAR image and to determine at least one difference value based on the comparison.

20. Training system comprising the system (900;

1000) according to claim 11 for rendering a Synthetic Aperture Radar (SAR) image.

21. Flight simulator comprising the system (900;

1000) according to claim 11 for rendering a Synthetic Aperture Radar (SAR) image.

22. Image interpretation system comprising a training system comprising the system (900;

1000) according to claim 11 for rendering a Synthetic Aperture Radar (SAR) image.

24. A computer program product comprising at least one non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising at least one executable portion configured for operating the system according to claim 11.