Camera system control for correcting bore-sight offset

• US 9,420,187 B2
• Filed: 12/13/2013
• Issued: 08/16/2016
• Est. Priority Date: 11/29/2013
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Avigilon Corporation (Motorola Solutions, Inc.)
• Inventors: Neufeld, Peter Wai, Afrooze, Sina
• Primary Examiner(s): HSU, AMY R
• Application Number:
  US14/106,538
• Publication Number:
  US 20150156422A1
• Time in Patent Office: 977 Days
• US Class Current: 1/1
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/66 Remote control of cameras or camera parts, e.g. by remote control devices
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/695 Control of camera direction for changing a field of view, e.g. pan, tilt or based on tracking of objects

Abstract

A camera system is provided that provides a smooth and centered zoom, even at high levels of magnification. The camera system corrects for misalignment between the optical axis of a lens and center of an image sensor. As a result of the misalignment, the center of an image will move during a zoom movement. The current camera system corrects for the misalignment as the zoom movement occurs. The correction is matched to the speed of the zoom in order to provide a fluid zoom movement.

Claims

1. A method of controlling a camera system to perform a zoom movement comprising:

receiving zoom information for performing a zoom movement;

determining zoom speed information of the camera system; and

moving, using one or more pieces of computer hardware, a displayed field of view of the camera system at a positioning speed based on the determined zoom speed information to correct for a bore-sight offset of the camera system as the zoom movement is performed.

2. The method of claim 1, wherein the zoom speed information provides an indication of a rate of change in lens magnification for zoom positions between a completely zoomed-out position and a completely zoomed-in position.

3. The method of claim 2, wherein the positioning speed is determined to move the displayed field of view a required amount to correct for the bore-sight offset while the zoom movement is performed.

4. The method of claim 2, wherein the zoom movement is performed by moving optical elements of a lens of the camera system.

5. The method of claim 1, wherein the position of the displayed field of view of the camera system is adjusted using at least one positioning motor.

6. The method of claim 5, wherein the at least one positioning motor comprises at least a pan motor and a tilt motor.

7. The method of claim 1, wherein the position of the displayed field of view is adjusted to compensate for the bore-sight offset resulting from a zoom movement amount determined from the zoom information.

8. The method of claim 1, further comprising:

adjusting the positioning speed at which the displayed field of view of the camera system is moved as the zoom movement is performed.

9. The method of claim 8, wherein the positioning speed is adjusted to match a current speed of the zoom movement based on the zoom speed information.

10. The method of claim 9, wherein the zoom speed information provides a plurality of linear segments approximating a non-linear relationship between zoom position and zoom speed.

11. The method of claim 10, wherein adjusting the positioning speed comprises:

determining that a current zoom position is associated with a next linear segment of the zoom speed information;

calculating a bore-sighting speed based on the zoom speed of the next linear segment and the bore-sight offset of the camera system; and

adjusting the positioning speed to equal the bore-sighting speed to correct for the bore-sight offset.

12. The method of claim 11, wherein the zoom speed information is provided as a lookup table allowing a zoom speed to be looked up based on a zoom position.

13. The method of claim 9, wherein the zoom speed information provides a non-linear relationship between zoom position and zoom speed.

14. The method of claim 1, wherein receiving zoom information comprises receiving an indication of a desired final zoom position.

15. The method of claim 1, wherein receiving zoom information comprises receiving an indication of a zoom motor speed to apply.

16. The method of claim 1, wherein the displayed field of view comprises a region of interest in a larger field of view captured by the camera system.

17. The method of claim 16, wherein moving the displayed field of view comprises translating the region of interest within the larger field of view captured by the camera system.

18. The method of claim 1, wherein the positioning speed is adjusted to match a current bore-sighting speed to correct for the bore-sight offset.

19. A camera system comprising:

a lens;

an image sensor; and

a processor for executing instructions stored in memory, the instructions when executed by the processor configuring the camera system to perform the following;

receive zoom information for performing a zoom movement;

determine zoom speed information of the camera system; and

move a displayed field of view of the camera system at a positioning speed based on the determined zoom speed information to correct for a bore-sight offset of the camera system as the zoom movement is performed.

20. The camera system of claim 19, wherein the zoom speed information provides an indication of a rate of change in magnification of the lens for zoom positions between a completely zoomed-out position and a completely zoomed-in position.

21. The camera system of claim 20, wherein the positioning speed is determined to move the displayed field of view a required amount to correct for the bore-sight offset while the zoom movement is performed.

22. The camera system of claim 20, wherein the zoom movement is performed by moving optical elements of the lens.

23. The camera system of claim 19, wherein the position of the displayed field of view of the camera system is adjusted using at least one positioning motor.

24. The camera system of claim 23, wherein the at least one positioning motor comprises at least a pan motor and a tilt motor.

25. The camera system of claim 19, wherein the position of the displayed field of view is adjusted to compensate for the bore-sight offset resulting from a zoom movement amount determined from the zoom information.

26. The camera system of claim 19, wherein the instructions when executed by the processor configure the camera system to adjust the positioning speed at which the displayed field of view of the camera system is moved as the zoom movement is performed.

27. The camera system of claim 26, wherein the positioning speed is adjusted to match a current speed of the zoom movement based on the zoom speed information.

28. The camera system of claim 27, wherein the zoom speed information provides a plurality of linear segments approximating a non-linear relationship between zoom position and zoom speed.

29. The camera system of claim 28, wherein to adjust the positioning speed comprises the following:

determine that a current zoom position is associated with a next linear segment of the zoom speed information;

calculate a bore-sighting speed based on the zoom speed of the next linear segment and the bore-sight offset of the camera system; and

adjust the positioning speed to equal the bore-sighting speed to correct for the bore-sight offset.

30. The camera system of claim 29, wherein the zoom speed information is provided as a lookup table allowing a zoom speed to be looked up based on a zoom position.

31. The camera system of claim 27, wherein the zoom speed information provides a non-linear relationship between zoom position and zoom speed.

32. The camera system of claim 19, wherein to receive zoom information comprises to receive an indication of a desired final zoom position.

33. The camera system of claim 19, wherein to receive zoom information comprises to receive an indication of a zoom motor speed to apply.

34. The camera system of claim 19, wherein the displayed field of view comprises a region of interest in a larger field of view captured by the camera system.

35. The camera system of claim 34, wherein to move the displayed field of view comprises to translate the region of interest within the larger field of view captured by the camera system.

36. The camera system of claim 19, wherein the positioning speed is adjusted to match a current bore-sighting speed to correct for the bore-sight offset.