ULTRASONIC CAMERA TRACKING SYSTEM AND ASSOCIATED METHODS

• US 20080095401A1
• Filed: 10/15/2007
• Published: 04/24/2008
• Est. Priority Date: 10/19/2006
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Polycom Incorporated (HP Inc.)
• Inventors: Feng, Jinwei, Nimri, Alain, Chu, Peter, Saleh, Youssef
• Granted Patent: US 8,249,298 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G01S 3/808 using transducers spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 5/22 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/28 takes precedence
• CPC Class Codes: H04N 7/15 Conference systems

Abstract

A camera tracking system includes a controllable camera, an array of microphones, and a controller. The microphones are positioned adjacent the controllable camera and are at least responsive to ultrasound emitted from a source. The microphones may additionally be capable of responding to sound in the audible spectrum. The controller receives ultrasound signals communicated from the microphones in response to ultrasound emitted from the source and processes the ultrasound signals to determine an at least approximate location of the source. Then, the controller sends one or more command signals to the controllable camera to direct at least approximately at the determined location of the source. The camera tracking system tracks the source as it moves and continues to emit ultrasound. The source can be an emitter pack having one or more ultrasonic transducers that produce tones that sweep form about 24-kHz to about 40-kHz.

Claims

1. A camera tracking apparatus, comprising:

a controllable camera;

a plurality of receivers being at least responsive to ultrasound emitted from a source; and

a controller communicatively coupled to the controllable camera and the receivers, the controller configured to;

receive ultrasound signals communicated from the receivers in response to ultrasound emitted from the source,

process the ultrasound signals to determine an at least approximate location of the source, and

control the controllable camera to direct at least approximately at the determined location of the source.

2. The apparatus of claim 1, wherein to control the controllable camera, the controller commands the controllable camera to tilt at least approximately to the determined location of the source.

3. The apparatus of claim 1, wherein to control the controllable camera, the controller commands the controllable camera to pan at least approximately to the determined location of the source.

4. The apparatus of claim 1, wherein to control the controllable camera, the controller commands the controllable camera to zoom at least approximately to the determined location of the source.

5. The apparatus of claim 1, wherein each of the receivers comprise a microphone having a substantially flat frequency response within a range of about 24-kHz to about 40-kHz.

6. The apparatus of claim 5, wherein the ultrasound emitted from the source comprises a tone sweeping in a range between about 24-kHz to about 40-kHz.

7. The apparatus of claim 5, wherein each of the microphones further comprises a frequency response within an audible range.

8. The apparatus of claim 1, further comprising a portable emitter as the source emitting the ultrasound, the emitter having one or more ultrasonic transducers.

9. The apparatus of claim 1, wherein to process the ultrasound signals to determine the at least approximate location of the source, the controller is configured to:

down sample the ultrasound signals,

filter the down sampled signals to substantial impulses, and

zero portions of the filtered signals to remove portions of the ultrasound signals caused by reflection.

10. The apparatus of claim 1, wherein at least two of the receivers are positioned along an axis intended to be substantially horizontally arranged with respect to the source, and wherein to process the ultrasound signals to determine the at least approximate location of the source, the controller is configured to:

calculate an approximate horizontal location of the source using phase differences in the ultrasound signals between the at least two receivers, and

determine a pan variable for the controllable camera based on the approximate horizontal location.

11. The apparatus of claim 1, wherein at least two of the receivers are positioned along an axis intended to be substantially vertically arranged with respect to the source, and wherein to process the ultrasound signals to determine the at least approximate location of the source, the controller is configured to:

calculate an approximate vertical location of the source using phase differences in the ultrasound signals between the at least two receivers, and

determine a tilt variable for the controllable camera based on the approximate vertical location.

12. The apparatus of claim 1, wherein at least two of the receivers are positioned along an axis, and wherein to process the ultrasound signals to determine the at least approximate location of the source, the controller is configured to:

calculate an approximate distance location of the source using curvature of a wave front of the ultrasound signals received at the at least two receivers, and

determine a zoom variable for the controllable camera based on the approximate distance location.

13. The apparatus of claim 1, further comprising memory storing a plurality of variables for candidate locations, the controller communicatively coupled to the memory and using the variables to process the ultrasound signals and determine the at least approximate location of the source.

14. A camera tracking method, comprising:

receiving ultrasound with a plurality of separate channels, the ultrasound emitted from a source;

determining an at least approximate location of the source by processing the ultrasound received with the separate channels; and

controlling a camera to at least approximately direct at the determined location of the source.

15. The method of claim 14, wherein receiving ultrasound with the plurality of separate channels comprise responding to ultrasound in a range of about 20-kHz to about 40-kHz at each of the separate channels.

16. The method of claim 14, wherein processing the ultrasound received with the separate channels comprises:

down-sampling signals of the ultrasound at each of the separate channels;

filtering the down sampled signals to substantial impulses; and

zeroing portions of the filtered signals to remove portions of the signals caused by reflection.

17. The method of claim 14, wherein determining the at least approximate location of the source comprises calculating a pan variable for the camera based on phase differences in ultrasound signals received by at least two of the separate channels arranged horizontally with respect to the source.

18. The method of claim 14, wherein determining the at least approximate location of the source comprises calculating a tilt variable for the camera based on phase differences in ultrasound signals received by at least two of the separate channels arranged vertically with respect to the source.

19. The method of claim 14, wherein determining the at least approximate location of the source comprises calculating a zoom variable for the camera based on curvature of a wave front of ultrasound signals received by at least two of the separate channels arranged along an axis.

20. A program storage device, readable by a programmable control device, comprising instructions stored on the program storage device for causing the programmable control device to perform a method according to claim 14.

21. A camera tracking system, comprising:

an emitter unit having at least one ultrasonic transducers emitting ultrasound;

a moveable camera;

a plurality of microphones positioned adjacent the camera and being capable of at least responding to ultrasound emitted by the at least one ultrasonic transducer; and

a control unit communicatively coupled to the moveable camera and the microphones, the control unit receiving ultrasound signals communicated from the microphones in response to ultrasound detected from the at least one ultrasonic transducer, the control unit processing the ultrasound signals to determine an at least approximate location of the at least one ultrasonic transducer and controlling the moveable camera to direct at least approximately at the determined location.

22. A camera tracking apparatus, comprising:

means for receiving ultrasound emitted from a source;

means for determining an at least approximate location of the source from the received ultrasound; and

means for controlling a camera to direct at least approximately at the determined location of the source.

23. The apparatus of claim 22, wherein the means for receiving ultrasound emitted from the source comprises means for receiving the ultrasound at a plurality of separate channels, at least two of the separate channels arranged along a first axis, and at least two of the separate channels arranged along a second axis substantially orthogonal to the first axis.

24. The apparatus of claim 22, wherein the means for determining the at least approximate location of the source from the received ultrasound comprises means for determining the at least approximate location based at least in part on phase differences in ultrasound received at a plurality of separate channels.

25. The apparatus of claim 22, wherein the means for controlling the camera to direct at least approximately at the determined location of the sources comprises means for panning, tilting, and zooming the camera to the determined location.