METHOD AND APPARATUS FOR THREE DIMENSIONAL TOMOGRAPHIC IMAGE RECONSTRUCTION OF OBJECTS

• US 20090021423A1
• Filed: 07/19/2007
• Published: 01/22/2009
• Est. Priority Date: 07/19/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Cheng, Shirley N., Wittenberg, Peter
• Granted Patent: US 7,642,953 B2
• Time in Patent Office: Days
• US Class Current: 342/25.A
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations

Abstract

In accordance with an embodiment, a system includes a plurality of vehicles and a central node. The plurality of vehicles each have radar systems used to collect radar data about the target object. Each in the plurality of vehicles moves in a path to collect a portion of the radar data using a sampling map to coordinate collection of the radar data by the plurality of vehicles and communicates with every other vehicle to identify uncollected portions of the radar data. The central node is in communication with the plurality of vehicles, wherein the central node receives the radar data from the plurality of vehicles and creates a three dimensional image from the radar data received from the plurality of vehicles using a tomographic reconstruction process.

Claims

1. A system for creating a three dimensional image of an target object, the system comprising:

a plurality of vehicles having radar systems used to collect radar data about the target object, wherein each in the plurality of vehicles moves in a path to collect a portion of the radar data using a sampling map to coordinate collection of the radar data by the plurality of vehicles and communicates with every other vehicle in the plurality of vehicles to identify uncollected portions of the radar data; and

a central node in communication with the plurality of vehicles, wherein the central node receives the radar data from the plurality of vehicles and creates the three dimensional image from the radar data received from the plurality of vehicles using a tomographic reconstruction process.

2. The system of claim 1, wherein the central node also collects the radar data.

3. The system of claim 1, wherein a particular vehicle in the plurality of vehicles generates a token identifying when a particular portion of the radar data is collected by the particular vehicle.

4. The system of claim 3, wherein the token includes an identification of the particular portion of the radar data collected by the particular vehicle.

5. The system of claim 1 further comprising:

a processing unit comprising;

a filter in communication with a radar system associated with a selected vehicle and capable of filtering the radar data received from the radar system;

a token bank capable of receiving tokens from a communications link with other vehicle in the plurality of vehicles, wherein the tokens received from a remote observer node in a plurality of observer nodes through the communications link are stored in the token bank, wherein a token identifies a position and a location of an observer node when the observer node collects the radar data;

a sinogram unit connected to the token bank, wherein the sinogram unit generates a sinogram used to identify a plurality of samples in a sampling space needed for reconstructing the three dimensional image of the target object;

a token generation unit connected to the filter, wherein the token generation unit generates in response to receiving the radar data from the radar system; and

an optimization algorithm unit connected to the sinogram unit capable of generating control instructions using the sinogram, wherein the control instructions are used to direct movement of the selected vehicle to collect a sample in the plurality of samples.

6. The system of claim 1, wherein the target object is a moving target object and wherein the plurality of vehicles updates an origin and an orientation of the sampling map to take into account a change in location of the moving target object to form an updated sampling map that identifies a set of collected portions of the radar data needed to create the three dimensional image of the moving target object and a set of uncollected portions of the radar data still needed to create the three dimensional image of the moving target object.

7. The system of claim 4, wherein the plurality of vehicles updates the sampling map by one of changing the sampling map and receiving a cue of where the target object is located from the central node.

8. The system of claim 4, wherein the plurality of vehicles update the sampling map periodically to take into account the change in location of the moving target object.

9. The system of claim 1, wherein the sampling map is a sinogram.

10. The system of claim 1, wherein the plurality of vehicles is selected from a group comprising a plurality of unmanned aerial vehicles;

a set of unmanned aerial vehicles and a set of manned vehicles;

a set of aircraft and a set of land vehicles;

a set of aerial vehicles, a set of water vehicles, and a set of aircraft.

11. The system of claim 1 further comprising:

an additional vehicle having a radar system used to collect the radar data about the target object, wherein the additional vehicle is stationary.

12. The system of claim 1, wherein radar systems for the plurality of vehicles are coherent radar systems.

13. An apparatus, comprising:

a coordinated network centric data collection system having a plurality of nodes moving in a coordinated formation to collect radar data about a target object in which different nodes in the plurality of nodes collect different portions of the radar data using a sampling map that identifies the different portions of the radar data needed to create a three dimensional image of the target object; and

a central node receives the different portions of the radar data collected by the plurality of nodes, constructs the three dimensional image of the target object from the different portion of the radar data.

14. The apparatus of claim 13, wherein the target object is identified using the three dimensional image of the target object.

15. The apparatus of claim 13, wherein each node in the coordinated network centric data collection system stores and updates a copy of the sampling map.

16. The apparatus of claim 13, wherein the sampling map is a sinogram and wherein the central node constructs the three dimensional image of the target object using a tomographic reconstruction process.

17. The apparatus of claim 16, wherein the different nodes collect the radar data in a form of three dimensional projections.

18. The apparatus of claim 13, wherein the central node uses a tomographic reconstruction process to construct the three dimensional image from three dimensional projections collected by the plurality of nodes.

19. The apparatus of claim 13, wherein the target object is a moving target object and wherein the coordinated network centric data collection system updates the sampling map to take into account a change in location of the moving target object to form an updated sampling map that identifies a set of collected portions of the radar data needed to create the three dimensional image of the moving target object and a set of uncollected portions of the radar data still needed to create the three dimensional image of the moving target object.

20. A processing unit for processing data collected by a selected observer node in a plurality of observer nodes, the processing unit comprising:

a filter in communication with a radar system associated with the selected observer node and capable of filtering radar data received from the radar system;

a token bank capable of receiving tokens from a communications link with other observer nodes in the plurality of observer nodes, wherein the tokens received from a remote observer node in the plurality of observer nodes through the communications link are stored in the token bank and wherein a token identifies a position and a location of an observer node when the observer node collects the radar data;

a sampling unit connected to the token bank, wherein the sampling unit generates a map used to identify a plurality of samples in a sampling space needed for reconstructing a three dimensional image of a target object;

a token generation unit connected to the filter, wherein the token generation unit generates a new token in response to receiving the radar data for a sample from the radar system; and

an optimization algorithm unit connected to the sampling unit in which the optimization algorithm unit is capable of generating control instructions using the map, wherein the control instructions are used to direct movement of the observer node to collect the sample in the plurality of samples.

21. A method for creating a three dimensional image of a target object, the method comprising:

coordinating movement of a plurality of vehicles to collect a selected amount of radar data needed to create the three dimensional image of the target object, wherein the plurality of vehicles have radar systems for collecting the radar data about the target object;

collecting the selected amount of the radar data from the plurality of vehicles; and

combining the selected amount of the radar data received from the plurality of vehicles to create the three dimensional image of the target object.

22. The method of claim 21, wherein the combining step comprises:

combining the selected amount of the radar data received from the plurality of vehicles using a tomographic reconstruction process to create the three dimensional image of the target object

23. The method of claim 21, wherein the collecting step comprises;

projecting a plurality of beams onto the target object from coherent radar systems located on the plurality of vehicles; and

collecting by each vehicle the radar data in response to projecting the plurality of beams.

24. The method of claim 23, wherein the plurality of beams projected onto the target object are projected sequentially or in a coordinated manner.

25. The method of claim 21, wherein the collecting step further comprises:

projecting a beam onto the target object from a radar system located on the central node.

26. The method of claim 21, wherein the collecting step comprises:

projecting a beam onto the target object from a radar system located on the central node; and

collecting by each vehicle the radar data in response to projecting the beam.

27. The method of claim 21, wherein the processing step comprises:

receiving the radar data from the plurality of vehicles at a central node to form received data; and

combining the received data at the central node using tomographic process to create the three dimensional image of the target object.

28. The method of claim 21, wherein the coordinating step comprises:

maintaining a sinogram identifying a set of collected portions of the radar data and a set of uncollected portions of the radar data; and

generating instructions to coordinate movement of the plurality of vehicles to collect the set of uncollected portions of the radar data.

29. The method of claim 21, wherein the target object is a moving target object and wherein the coordinating step further comprises:

updating a map to take into account changes in a location of the target object.

30. The method of claim 21, wherein the three dimensional image has a resolution sufficient to identify the target object.