Measuring camera attitude

• US 6,965,397 B1
• Filed: 12/27/1999
• Issued: 11/15/2005
• Est. Priority Date: 11/22/1999
• Status: Expired due to Term

• Current Assignee: Sportsmedia Technology Corporation
• Original Assignee: Sportvision, Inc. (Sportsmedia Technology Corporation)
• Inventors: O'Brien, Terence J., Phillips, Alan C., Neubarth, Stuart K., White, Marvin S., Cavallaro, Richard H., Milnes, Kenneth A., Honey, Stanley K., Lazar, Matthew T.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Genco, Brian C.
• Application Number:
  US09/472,635
• Time in Patent Office: 2,150 Days
• Field of Search: 348/208, 348/211, 348/169, 348/208.2, 348/208.3, 396/13, 396/421, 396/52, 396/53, 352/53, 74/52.2, 333/18, 333/20, 333/21, 333/23, 333/28
• US Class Current: 348/208.2
• CPC Class Codes: H04N 5/222 Studio circuitry; Studio devices; Studio equipment cameras or camera modules comprising electronic image sensors, or control thereof H04N23/00
• CPC Class Codes: H04N 5/262 Studio circuits, e.g. for mixing, switching-over, change of character of image, other special effects ; Cameras specially adapted for the electronic generation of special effects
• CPC Class Codes: H04N 5/2723 Insertion of virtual advertisement; Replacing advertisements physical present in the scene by virtual advertisement data processing systems or methods specially adapted for marketing G06Q30/02
• CPC Class Codes: H04N 5/28 Mobile studios
• CPC Class Codes: Y10T 74/1218 Combined

Abstract

A system is disclosed for using camera attitude sensors with a camera. A camera assembly includes a tripod base, a tripod head interface mounted on the tripod base, a tripod head mounted on the tripod head interface and a camera mounted on the tripod head. The tripod head enables the camera to pan and tilt. The system also includes a first optical encoder for detecting the amount that the camera has been panned and a second optical encoder for detecting the amount that the camera has been tilted. Two inclinometers are mounted on the tripod head interface to measure attitude of the tripod head. Two gyroscopes (“gyros”) are mounted on the camera assembly. Data from the encoders, gyros and inclinometers are packaged and sent to graphics production equipment to be used for enhancing video captured by the camera.

Claims

1. A system for using attitude sensors with a camera, said camera being part of a camera assembly, said camera assembly including a fixed portion and a movable portion, said system comprising:

a first sensor coupled to said camera assembly, said first sensor measures movement of said movable portion relative to said fixed portion; and

a first inclinometer coupled to said camera assembly, said first inclinometer measures an angle of a first axis of said fixed portion of said camera assembly, said measured angle including an actual angle component attributable to a gravitational force on said first inclinometer and an error component attributable to an acceleration force on said first inclinometer;

a first gyro coupled to said camera assembly, said first gyro measures a relative angular change of said first axis, said measured relative angular change including an actual relative angular change component substantially equal to said actual angle component of said angle measured by said first inclinometer and an error component attributable to at least one of offset and drift of said first gyro;

circuitry adapted to receive said measured angle and said measured relative angular change, said circuitry combines said measured angle and said measured relative angular change to remove said error component of said measured angle and said error component of said measured relative angular change in order to determine a value of said actual relative angular change component.

2. A system according to claim 1, wherein:

said first sensor measures rotation of said movable portion about said first axis.

3. A system according to claim 2, wherein:

said first inclinometer measures a component of the movement of said first axis.

4. A system according to claim 1, wherein:

said first sensor is an optical encoder.

5. A system according to claim 1, further comprising:

a second inclinometer coupled to said camera assembly, said first inclinometer and said second inclinometer are used to measure an orientation of said camera assembly.

6. A system according to claim 5, wherein:

said first sensor is coupled to said movable portion;

said first inclinometer is coupled to said fixed portion; and

said second inclinometer is coupled to said fixed portion.

7. A system according to claim 5, wherein:

said first sensor measures panning of said camera;

said first inclinometer measures roll of said fixed portion; and

said second inclinometer measures pitch of said fixed portion.

8. A system according to claim 5, wherein:

said first sensor measures tilting of said camera;

said first inclinometer measures roll of said fixed portion; and

said second inclinometer measures pitch of said fixed portion.

9. A system according to claim 5, wherein:

data from said first sensor is combined with data from said first inclinometer and said second inclinometer in order to describe said camera'"'"'s orientation.

10. A system according to claim 5, wherein:

data from said first sensor is combined with data from said first inclinometer and said second inclinometer, said combined data is used to transform a location in a first coordinate system to a position in a second coordinate system.

11. A system according to claim 5, further comprising:

a second sensor coupled to said camera assembly, said first sensor measures movement of said movable portion about said first axis and said second sensor measures movement of said movable portion about a second axis, said second inclinometer measures movement of said second axis.

12. A system according to claim 1, further comprising:

one or more processors, said one or more processors receive data from said first inclinometer, said first gyro, and said first sensor, said one or more processors programmed to determine attitude parameters describing an orientation of said camera based on said data from said first inclinometer, said first gyro, and said first sensor.

13. A system according to claim 12, wherein:

said one or more processors use said attitude parameters to transform a location in a first coordinate system to a position in a second coordinate system.

14. A system according to claim 1, wherein:

said fixed portion includes a tripod and a tripod head interface;

said movable portion includes at least a portion of a tripod head and said camera;

said first sensor is coupled to said tripod head;

said first gyro is coupled to said tripod head interface; and

said first inclinometer is coupled to said tripod head interface.

15. A system according to claim 1, further comprising:

sensor electronics located with said camera assembly and in communication with said first sensor and said first inclinometer, said sensor electronics reads data from said first sensor, said first gyro, and said first inclinometer and packages said data for transmission to a processor.

16. A system according to claim 15, wherein:

said sensor electronics encodes said packaged data for transmission in an audio signal to a first location, said processor being located at said first location.

17. A system according to claim 1, further comprising:

a second inclinometer coupled to said camera assembly, said second inclinometer measures an angle of a second axis of said fixed portion of said camera assembly, said first inclinometer is mounted in a first plane, said second inclinometer is mounted in a second plane, said first plane being orthogonal to said second plane;

a second sensor coupled to said movable portion, said first sensor and said second sensor are optical encoders, said first sensor measures rotation of said movable portion about said first axis, said second sensor measures rotation of said movable portion about said second axis, said first and second inclinometers measure movement of said first axis and said second axis;

a processor programmed to combine data from said first inclinometer, said second inclinometer, said first gryo, said first sensor and said second sensor in order to describe an orientation of said camera, said processor is in communication with said first inclinometer, said second inclinometer, said first gryo, said first sensor and said second sensor.

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

a second gyro in communication with said processor, said processor combines data from said first gyro and said second gyro with data from said first inclinometer, said second inclinometer, said first sensor and said second sensor.

19. A system according to claim 1, wherein:

said first inclinometer is coupled with said fixed portion of said camera assembly.

26. A system according to claim 1, wherein:

said circuitry determines a value of said actual relative angular change component by determining a value of said actual angle component, said actual angle component being substantially equal to said actual relative angular change component.

27. A system according to claim 1, wherein:

said gyro is a fiber optic gyro.

28. A system according to claim 1, wherein said circuitry comprises:

a first summer, said first summer subtracts said measured relative angular change of said first axis from said measured angle of said first axis, said subtracting resulting in a value equal to a difference between said error component attributable to an acceleration force on said first inclinometer and said error component attributable to at least one of offset and drift of said first gyro;

a filter, said filter filters said value resulting from said subtraction to remove said error component attribute to an acceleration force on said first inclinometer, said filtering resulting in a value equal to an inverse of said error component attributable to at least one of offset and drift of said first gyro; and

a second summer, said second summer adds said measured relative angular change of said first axis to said value resulting from said filtering, said adding resulting in said value of said actual relative angular change component.

20. A method for using attitude sensors with a camera, said camera being part of a camera assembly, said camera assembly including a fixed portion and a movable portion, said method comprising:

sensing data from a first sensor, said first sensor measures movement of said movable portion relative to said fixed portion;

sensing data from a first inclinometer, said first inclinometer measures an angle of a first axis of said camera assembly, said measured angle including an actual angle component attributable to a gravitational force on said first inclinometer and an error component attributable to an acceleration force on said first inclinometer;

sensing data from a first gyro, said first gyro measures a relative angular change of said first axis, said measured relative angular change including an actual relative angular change component substantially equal to said actual angle component of said angle measured by said first inclinometer and an error component attributable to at least one of offset and drift of said first gyro; and

combining said data from said first sensor, said data from said first inclinometer, and said data from said first gyro, said combining includes combining said measured angle and said measured relative angular change to remove said error component of said measured angle and said error component of said measured relative angular change in order to determine a value of said actual relative angular change component.

21. A method according to claim 20, wherein said step of combining includes:

creating one or more transformation matrices using said data from said first sensor, said data from said first gyro, and said data from said first inclinometer.

22. A method according to claim 20, further comprising the step of:

selecting a location in a scene;

converting said location to a position in a video image from said camera, said step of converting is based on said step of combining; and

adding a graphic to said video image from said camera at said position.

23. A method according to claim 20, wherein:

said first sensor measures rotation of said movable portion about said first axis;

said first gyro measures a component of the orientation of said first axis; and

said first inclinometer measures a component of the orientation of said first axis.

24. A method according to claim 20, further comprising the step of:

adding said data from said first sensor, said data from said first gyro, and said data from said first inclinometer to an audio signal for transmission to a first location, a first processor is located at said first location, said first processor performs said step of combining.

25. A method according to claim 20, further comprising

sensing data from a second gyro;

sensing data from a second sensor; and

sensing data from a second inclinometer;

wherein said step of combining includes combining said data from said first sensor, said data from said first gyro, said data from said first inclinometer, said data from said second sensor, said data from said second gryo, and said data from said second inclinometer.

29. A method according to claim 20, wherein said step of combining comprises:

subtracting said measured relative angular change of said first axis from said measured angle of said first axis, said subtracting resulting in a value equal to a difference between said error component attributable to an acceleration force on said first inclinometer and said error component attributable to at least one of offset and drift of said first gyro;

filtering said value resulting from said subtraction to remove said error component attribute to an acceleration force on said first inclinometer, said filtering resulting in a value equal to an inverse of said error component attributable to at least one of offset and drift of said first gyro; and

adding said measured relative angular change of said first axis to said value resulting from said filtering, said adding resulting in said value of said actual relative angular change component.

30. A method according to claim 20, wherein:

said first inclinometer measures attitude information of at least a portion of said fixed portion of said camera assembly.

31. A system for using attitude sensors with a camera, said camera being part of a camera assembly, said camera assembly including a fixed portion and a moveable portion, said system comprising:

a first sensor coupled to said camera assembly, said first sensor measures movement of said movable portion with respect to said fixed portion along a first axis;

a first gyro coupled to said camera assembly, said first gyro measures a relative angular change of said first axis, said measured relative angular change of said first axis including an actual relative angular change component and an error component attributable to at least one of offset and drift of said first gyro;

a first inclinometer coupled to said camera assembly, said first inclinometer measures an angle of said first axis, said measured angle of said first axis including an actual angle component attributable to a gravitational force on said first inclinometer and an error component attributable to an acceleration force on said first inclinometer;

a second sensor coupled to said camera assembly, said second sensor measures movement of said movable portion with respect to said fixed portion along a second axis;

a second inclinometer coupled to said camera assembly, said second inclinometer measures an angle of said second axis, said measured angle of said second axis including an actual angle component attributable to a gravitational force on said second inclinometer and an error component attributable to an acceleration force on said second inclinometer;

a second gyro coupled to said camera assembly, said second gyro measures a relative angular change of said second axis, said measured relative angular change of said second axis including an actual relative angular change component and an error component attributable to at least one of offset and drift of said second gyro; and

circuitry adapted to receive said measured angle of said first axis, said measured relative angular change of said first axis, said measured angle of said second axis, and said measured relative angular change of said second axis, said circuitry combines said measured angle of said first axis and said measured relative angular change of said first axis to remove said error component of said measured angle of said first axis and said error component of said measured relative angular change of said first axis in order to determine a value of said actual relative angular change component for said first axis, said circuitry combines said measured angle of said second axis and said measured relative angular change of said second axis to remove said error component of said measured angle of said second axis and said error component of said measured relative angular change of said second axis in order to determine a value of said actual relative angular change component for said second axis.

32. A system according to claim 31, further comprising:

one or more processors receiving and combining data from said first gyro, said second gyro, said first inclinometer, said second inclinometer, said first sensor and said second sensor;

said one or more processors use said combined data to add a graphic to a video image from said camera at a first position in said video image, said graphic corresponds to a three dimensional location within a field of view of said camera, said three dimensional location corresponds to said first position in said video image.

33. A system according to claim 32, further comprising:

an audio signal generator in communication with and receiving sensor data from said first gyro, said second gyro, said first inclinometer, said second inclinometer, said first sensor and said second sensor, said audio signal generator creates a compatible audio signal which includes said sensor data, said audio signal generator communicates said compatible audio signal to said camera for transmission in said camera audio signal; and

a data extractor receiving said camera audio signal and extracting said sensor data, said data extractor in communication with said one or more processors.