Method for fusing overhead imagery with automatic vessel reporting systems

• US 8,411,969 B1
• Filed: 08/06/2010
• Issued: 04/02/2013
• Est. Priority Date: 08/06/2010
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Joslin, Erin, Buck, Heidi, Hobbs, Stephen, Fu, Jerry, Waller, Matthew
• Primary Examiner(s): Lu, Tom Y
• Assistant Examiner(s): CONWAY, THOMAS A
• Application Number:
  US12/851,738
• Time in Patent Office: 970 Days
• Field of Search: None
• US Class Current: 382/224
• CPC Class Codes: G06V 20/13 Satellite images

Abstract

Systems and methods for processing satellite imagery include a satellite, a processor, a database of vessel position data and a computer readable storage medium. The methods process satellite imagery by fusing the imagery with information from the database to automatically identify ships. The methods include the steps of defining an Area of Interest (AOI) and Time of Interest (TOI) for the image and enlarging the AOI according to a time window that brackets the TOI and an assumed vessel maximum speed. Vessel position data from the database for all vessels within the enlarged AOI and the time window is accessed, and fused to imagery position data using Chi-Squared probability analysis. If the analysis meets predetermined probability threshold criteria, the vessel position is assigned to the satellite image to identify the vessel. Otherwise, the operator is alerted that imaged vessels do not correlate to vessel reporting data, or vice versa.

Claims

1. A method for identifying a vessel in a satellite image, said vessel having imagery position data in said image, said method comprising the steps of:

A) defining an Area of Interest (AOI) and a Time of Interest (TOI) for said satellite image;

B) defining a predetermined time window around said TOI;

C) enlarging said AOI according to said predetermined time window and an assumed maximum speed for said vessel;

D) retrieving vessel position data from a database for all vessels within said enlarged AOI;

E) comparing said vessel position data from said step D) to said imagery position data from said step A); and

,

F) assigning an identity to said imaged vessel when said step E) meets a predetermined probability threshold.

2. The method of claim 1 wherein said step E) further comprises the step of:

G1) filtering said satellite image from said step A) to remove said imaged vessels that are actually man-made objects and land masses, said step G1) occurring before said step E).

3. The method of claim 1 wherein said step E) further comprises the step of:

G2) updating said imagery position data to account for vessel wakes, said step G2) occurring before said step E).

4. The method of claim 1 wherein said step F) is accomplished using a Chi-Squared probability analysis.

5. The method of claim 1 wherein said step D) further comprises the step of:

consolidating said vessel position data that pertains to the same unique vessel.

6. The method of claim 5, wherein said step D) is accomplished by retrieving at least one position data point within said time window prior to said TOI and one position data point after said TOI.

7. The method of claim 6, wherein said step D) is accomplished by retrieving at least one position data point prior to said TOI and one position data point after said TOI.

8. The method of claim 1 wherein said database used in said step D) is the Automatic Identification System (AIS).

9. The method of claim 8 further comprising the step of:

H) alerting an operator if at least one said vessel does not have an assigned identity resulting from said step F).

10. The method of claim 8 further comprising the step of:

I) alerting an operator if said vessel position data is not assigned to one said vessel after completion of said step F).

11. A system for processing satellite imagery, comprising:

a satellite for generating satellite images

a processor connected to said satellite;

a data remote from said processor; and

,

a computer readable storage medium installed on said processor, said medium storing instructions that, when executed by said processor, cause said processor to perform a method for processing said overhead images from said satellite to automatically identify ships, said method comprising the steps of;

A) defining an Area of Interest (AOI) and a Time of Interest (TOI) for said satellite image, said satellite image having at least one imaged vessel, each said vessel having imagery position data;

B) defining a predetermined time window around said TOI;

C) enlarging said AOI according to said predetermined time window and an assumed maximum speed for said vessel;

D) retrieving vessel position data from a database for all vessels within said enlarged AOI;

E) fusing said vessel position data from said step C) to imagery position data from said step A); and

,

F) assigning an identity to said vessel when said step E) meets a predetermined probability threshold.

12. The system of claim 11 wherein said database used in said remote database is the Automatic Identification System (AIS).

13. The system of claim 11 wherein said instructions further comprise the step of:

G1) filtering said satellite image from said step A) to remove said imaged vessels that are actually man-made objects and land masses, said step G1 occurring before said step E).

14. The system of claim 11 wherein said instructions further comprise the step of:

G2) updating said imagery position data to account for vessel wakes, said step G2) occurring before said step E).

15. The system of claim 11 wherein said step F) of said instructions is accomplished using a Chi-Squared probability analysis.

16. The system of claim 11 wherein said instructions further comprise the step of:

H) alerting an operator if at least one of said vessels does not have assigned AIS reporting data.

17. The system of claim 11 wherein said instructions further comprise the step of:

I) alerting an operator if said vessel position data is not assigned to at least one said vessel after completion of said step F).

18. The system of claim 11 wherein said step D) of said instructions further comprises the step of:

D1) consolidating vessel position data that pertains to the same unique vessel.

19. The system of claim 18, wherein said step D1) of said instructions is accomplished by retrieving at least one position data point within said time window.

20. The system of claim 19, wherein said step D1) of said instructions is accomplished by retrieving at least one position data point prior to said TOI and one position data point after said TOI.