Camera system control for correcting bore-sight offset

• US 9,584,731 B2
• Filed: 07/22/2016
• Issued: 02/28/2017
• 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:
  US15/217,484
• Publication Number:
  US 20160330382A1
• Time in Patent Office: 221 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 system comprising:

a control system configured to issue commands;

a camera system in communication with and physically separated from the control system, the camera system including;

a) a lens including optical elements;

b) an image sensor configured to capture images storable within the system; and

c) camera control apparatus configured to;

i. receive a zoom command from the control system to perform a zoom movement within the camera system;

ii. determine zoom speed information of the camera system; and

iii. 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 in accordance with the zoom command.

2. The system of claim 1, 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.

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

4. The system of claim 2, wherein optical elements of the lens are configured to perform the zoom movement.

5. The system of claim 1, wherein the camera system further includes at least one positioning motor configured to effect adjustment of the position of the displayed field of view of the camera system.

6. The system of claim 5, wherein each zoom position is associated with a positioning motor offset required to correct for the bore-sight offset at the zoom position.

7. The system of claim 5, wherein the at least one positioning motor includes at least a pan motor and a tilt motor.

8. The system of claim 7, wherein the displayed field of view includes a region of interest in a larger field of view captured by the camera system, and wherein the displayed field of view of the camera is adjustable using a combination of the at least one positioning motor and translation of the region of interest within the larger field of view captured by the camera system.

9. The system 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 command.

10. The system of claim 1, wherein the camera control apparatus is further configured to adjust the positioning speed at which the displayed field of view of the camera system is moved as the zoom movement is performed.

11. The system of claim 10, wherein the positioning speed is adjustable to match a current speed of the zoom movement based on the zoom speed information.

12. The system of claim 11, wherein the zoom speed information provides a plurality of linear segments approximating a non-linear relationship between zoom position and zoom speed.

13. The system of claim 11, wherein the zoom speed information provides a non-linear relationship between zoom position and zoom speed.

14. The system of claim 11, wherein each of the linear segments is associated with a corresponding positioning correction required to correct the bore-sight offset.

15. The system of claim 11, wherein the zoom speed information is represented as a closed form equation.

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

17. The system of claim 1, wherein the camera system is in a location remote from the control system.

18. The system of claim 1, wherein the camera control apparatus is a processor.

19. A memory having stored thereon instructions for execution by a processor comprising part of a camera system, wherein the camera system also comprises a lens and an image sensor and wherein the instructions when executed by the processor cause the camera system to perform the following:

receive zoom information for performing a zoom movement;

determining 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 memory of claim 19, wherein the zoom movement is performed by moving optical elements of a lens of the camera system.

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

22. The memory of claim 21, wherein each zoom position is associated with a positioning motor offset required to correct for the bore-sight offset at the zoom position.

23. The memory of claim 21, wherein the at least one positioning motor comprises at least a pan motor and a tilt motor.

24. The memory of claim 23, wherein the displayed field of view comprises a region of interest in a larger field of view captured by the camera system, and wherein the displayed field of view of the camera is adjusted using a combination of the at least one positioning motor and translation of the region of interest within the larger field of view captured by the camera system.

25. The memory 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.

26. The memory of claim 25, wherein the positioning speed is adjusted to match a current speed of the zoom movement based on the zoom speed information.

27. The memory of claim 26, wherein the zoom speed information provides a plurality of linear segments approximating a non-linear relationship between zoom position and zoom speed.

28. The memory of claim 27, wherein to adjust the positioning speed comprises the following:

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.

29. The memory of claim 28, wherein to determine that the current zoom position is associated with the next linear segment comprises to determine that the current zoom position has crossed a position threshold indicating that the zoom speed should be approximated by the next linear segment.

30. The memory of claim 26, wherein each of the linear segments is associated with a corresponding positioning correction required to correct the bore-sight offset.

31. The memory of claim 26, wherein the zoom speed information is represented as a closed form equation.