System and method for tracking

• US 8,854,594 B2
• Filed: 08/31/2010
• Issued: 10/07/2014
• Est. Priority Date: 08/31/2010
• Status: Active Grant

• Current Assignee: CAST Group of Companies, Inc.
• Original Assignee: CAST Group of Companies, Inc.
• Inventors: Densham, Gilray, Eichel, Justin
• Primary Examiner(s): Vaughn, Jr., William C
• Assistant Examiner(s): PEREZ FUENTES, LUIS M
• Application Number:
  US12/872,956
• Publication Number:
  US 20120050535A1
• Time in Patent Office: 1,498 Days
• Field of Search: 340/870, 342/451, 348143-169, 382/114, 482/1
• US Class Current: 349/159
• CPC Class Codes: G01S 3/7864 T.V. type tracking systems
• CPC Class Codes: G01S 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49
• CPC Class Codes: H04N 5/2224 related to virtual studio applications
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

Systems and methods are provided for tracking at least position and angular orientation. The system comprises a computing device in communication with at least two cameras, wherein each of the cameras are able to capture images of one or more light sources attached to an object. A receiver is in communication with the computing device, wherein the receiver is able to receive at least angular orientation data associated with the object. The computing device determines the object'"'"'s position by comparing images of the light sources and generates an output comprising the position and angular orientation of the object.

Claims

1. A system for tracking one or more objects, the system comprising:

a tracking engine comprising a motion captor configured to receive a series of images of one or more light sources attached to an object of the one or more objects, the series of images captured by at least two or more cameras, an object identifier for identifying the object, and a state machine calculator for computing a current state of the object;

a receiver in communication with the tracking engine and configured to receive at least angular orientation data and another object ID associated with the object;

the tracking engine configured at least to;

analyze the series of images to determine which of the one or more light sources strobe;

characterize a light source that strobes as a tracking light source and to ignore a light source that does not strobe when further analyzing the series of images;

determine a position of the tracking light source by determining a pixel location of the tracking light source in the series of images and applying triangulation to the series of images;

determine if at least one of a previous position and a previous heading of the object, at least one of which is associated with a known object ID, can be compared with the position and, if not, detect a strobe pattern of the tracking light source from the series of images;

after determining that the detected strobe pattern matches a known strobe pattern associated with the known object ID, associate the known object ID with the position of the tracking light source; and

generate an output of the current state of the object comprising the position, the angular orientation data, and the known object ID of the object when the known object ID and the other object ID match.

2. The system of claim 1 further comprising the at least two cameras, which are in communication with the tracking engine.

3. The system of claim 1 wherein each of the one or more light sources comprise an infrared light emitting diode and the cameras are sensitive to infrared light.

4. The system of claim 1 wherein the receiver is also able to receive inertial acceleration data associated with the object.

5. The system of claim 1 wherein the angular orientation data comprises roll, pitch, and yaw and the position comprises X, Y, and Z coordinates.

6. The system of claim 1 wherein the angular orientation data is configured to be measured by one or more gyroscopes attached to the object.

7. The system of claim 4 wherein the inertial acceleration data is configured to be measured by one or more accelerometers attached to the object.

8. The system of claim 1 wherein, when at least one of the previous position and the previous heading of the object can be compared with the position:

the receiver configured to also receive inertial acceleration data associated with the object;

the tracking engine configured to determine an acceleration of the tracking light source by comparing the series of images; and

,

after determining that the acceleration determined from the series of images is approximately equal to the received inertial acceleration data, the tracking engine associating the known object ID with the position.

9. The system of claim 1 wherein at least one of the previous position and the previous heading of the object can be compared with the position when the tracking engine determines that the previous position is within an expected vicinity of the position of the tracking light source, and if so, associating the known object ID with the position.

10. The system of claim 1 wherein, after associating the tracking light source'"'"'s position with the known object ID, the tracking engine is configured to determine if a subsequent position of the tracking light source in subsequent images is within an expected vicinity of the tracking light source'"'"'s position, and if so, associating the known object ID with the subsequent position.

11. The system of claim 1 wherein the tracking engine is configured to only compare the images of the one or more light sources that have the known strobe pattern.

12. The system of claim 1 further comprising a transmitter, wherein the transmitter is configured to send a beacon mode selection to control when the one or more lights are displayed and when the angular orientation data is received.

13. The system of claim 1, wherein the state machine calculator uses a Kalman filter or an extended Kalman filter to generate the output comprising the position and the angular orientation of the object.

14. The system of claim 4 wherein, after the tracking engine detecting that only one of the cameras is able to detect the tracking light source, or none of the cameras are able to detect the tracking light source:

the tracking engine configured to identify a last known position of the object as determined from the series of images; and

the tracking engine configured to determine a new position of the object by combining the inertial acceleration data with the last known position.

15. The system of claim 1 further comprising a tracking apparatus configured to be in communication with the receiver, the tracking apparatus comprising:

the one or more light sources able to be tracked by at least two cameras for determining position;

an inertial measurement unit able to measure at least roll, pitch and yaw;

a wireless radio for transmitting at least measurements obtained from the inertial measurement unit and an associated object ID, the associated object ID being the other object ID received by the receiver; and

,

a processor for controlling the one or more light sources to operate according to a strobe pattern to also communicate the associated object ID.

16. The system of claim 15 wherein the one or more light sources comprise one or more infrared light emitting diodes.

17. The system of claim 15 wherein the inertial measurement unit is able to measure acceleration along the X, Y and Z axes.

18. The system of claim 15 wherein the tracking apparatus further comprises a battery for powering the tracking apparatus.

19. The system of claim 15 wherein the tracking apparatus further comprises a memory for storing one or more beacon modes, the one or more beacon modes determining at least one of:

which one or more types of measurements obtained from the inertial measurement unit are to be transmitted;

a time period that the one or more light sources is active; and

a time period that measurements obtained from the inertial measurement unit are transmitted to the computing device.

20. The system of claim 15 wherein the tracking apparatus is able to be attached to an object and further comprises a belt, wherein the belt is able to be wrapped around the object.

21. The system of claim 1 wherein the tracking engine is implemented by a computing device.

22. The system of claim 1 wherein the tracking engine is implemented by multiple computing devices.

23. A method performed by a computing system for tracking one or more objects, the method comprising:

receiving a series of images of one or more light sources attached to an object of the one or more objects, the series of images captured by at least two or more cameras;

analyzing the series of images to determine which of the one or more light sources strobe;

characterizing a light source that strobes as a tracking light source and ignoring a light source that does not strobe when further analyzing the series of images;

determining a position of the tracking light source by determining a pixel location of the tracking light source in the series of images and applying triangulation to the series of images;

determining if at least one of a previous position and a previous heading of the object, at least one of which is associated with a known object ID, can be compared with the position and, if not, detecting a strobe pattern of the tracking light source from the series of images;

after determining that the detected strobe pattern matches a known strobe pattern associated with the known object ID, associating the known object ID with the position of the tracking light source;

receiving at least angular orientation data and another object ID associated with the object; and

,

generating an output combining the position, the angular orientation, and the known object ID of the object when the known object ID and the other object ID match.

24. The method of claim 23 where the images are of a single light source attached to the object.

25. The method of claim 23 wherein each of the one or more light sources comprise an infrared light emitting diode and the computing system receives the images from the at least two cameras, which are sensitive to infrared light.

26. The method of claim 23 further comprising receiving inertial acceleration data associated with the object.

27. The method of claim 23 wherein the angular orientation data comprises roll, pitch, and yaw and the position comprises X, Y, and Z coordinates.

28. The method of claim 23 wherein the angular orientation data is measured by one or more gyroscopes attached to the object.

29. The method of claim 26 wherein the inertial acceleration data is measured by one or more accelerometers attached to the object.

30. The method of claim 23 wherein, when at least one of the previous position and the previous heading of the object can be compared with the position:

receiving inertial acceleration data associated with the object;

determining an acceleration and a position of the tracking light source by comparing the series of images; and

,

after determining that the acceleration determined from the series of images is approximately equal to the received inertial acceleration data, associating the known object ID with the position.

31. The method of claim 23 wherein at least one of the previous position and the previous heading of the object can be compared with the position when the previous position is within an expected vicinity of the position of the tracking light source, and if so, associating the known object ID with the position.

32. The method of claim 23 wherein, after associating the tracking light source'"'"'s position with the known object ID, determining if a subsequent position of the tracking light source in subsequent images is within an expected vicinity of the tracking light source'"'"'s position, and if so, associating the known object ID with the subsequent position.

33. The method of claim 23 wherein only images of the one or more light sources that have the known strobe pattern are compared to determine the position.

34. The method of claim 23 further comprising sending a beacon mode selection via a transmitter to control when the one or more lights are displayed and when the angular orientation data is received.

35. The method of claim 23 further comprising using a Kalman filter or an extended Kalman filter to generate the output comprising the position and the angular orientation of the object.

36. The method of claim 26 wherein, after detecting that only one of the cameras is able to detect the tracking light source, or none of the cameras are able to detect the tracking light source:

identifying a last known position of the object as determined from the series of images; and

determining a new position of the object by combining the inertial acceleration data with the last known position.

37. The method of claim 23 wherein a tracking apparatus is in communication with the computing system, and the method further comprising:

the tracking apparatus activating the one or more light sources, the one or more light sources able to be tracked by the at least two cameras for determining position;

the tracking apparatus measuring at least roll, pitch and yaw on the same object using an inertial measurement unit attached to the object;

the tracking apparatus wirelessly transmitting the measurements from the inertial measurement unit and an associated object ID to the computing device, the associated object ID being the other object ID received by the computing system; and

,

the tracking apparatus controlling the one or more light sources to operate according to a strobe pattern to also communicate the associated object ID.

38. The method of claim 37 wherein the one or more light sources comprises one or more infrared light emitting diodes.

39. The method of claim 37 wherein the inertial measurement unit is able to measure acceleration along the X, Y and Z axes.

40. The method of claim 37 further comprising activating one or more beacon modes, the one or more beacon modes determining at least one of:

which one or more types of measurements obtained from the inertial measurement unit are to be transmitted;

a time period that the one or more light sources are active; and

a time period that measurements obtained from the inertial measurement unit are transmitted to the computing system.

41. A non-transitory computer readable medium comprising processor executable instructions for tracking one or more objects, the processor executable instructions comprising:

receiving a series of images of one or more light sources attached to an object of the one or more objects, the series of images captured by at least two or more cameras;

analyzing the series of images to determine which of the one or more light sources strobe;

characterizing a light source that strobes as a tracking light source and ignoring a light source that does not strobe when further analyzing the series of images;

determining a position of the tracking light source by determining a pixel location of the tracking light source in the series of images and applying triangulation to the series of images;

determining if at least one of a previous position and a previous heading of the object, at least one of which is associated with a known object ID, can be compared with the position and, if not, detecting a strobe pattern of the tracking light source from the series of images;

after determining that the detected strobe pattern matches a known strobe pattern associated with the known object ID, associating the known object ID with the position of the tracking light source;

receiving at least angular orientation data and another object ID associated with the object; and

,

generating an output combining the position, the angular orientation, and the known object ID of the object when the known object ID and the other object ID match.