Method and system for image centering during zooming

1. A method of centering an object in the field of view of a camera during zooming, the method comprising:

setting a camera zoom to a first magnification factor to configure the camera to have a first field of view;

positioning the camera to have an object in a first position in the first field of view;

capturing a first image with the camera at the first magnification factor;

setting the camera zoom to a second magnification factor to configure the camera to have a second field of view with the second magnification factor being greater than the first magnification factor;

capturing a second image with the camera at the second magnification factor;

digitally altering a portion of the first image to create a third image with a magnification factor equivalent to the second magnification factor;

comparing the third image with the second image to determine an offset of the object from the first position of the object to the position of the object in the third image; and

adjusting the camera to be centered to an optical center of the camera during zooming based on the determined offset.

2. A method as recited in claim 1 wherein positioning the camera to have an object in a first position in the first field of view comprises positioning the camera to center the object in the first field of view.

3. A method as recited in claim 1 further comprising:

capturing a fourth image with the camera at a third magnification factor;

digitally altering a portion of the first image to create a fifth image with a magnification factor equivalent to the third magnification factor,

comparing the fifth image with the fourth image to determine an offset of the object from the first position of the object to the position of the object in the fourth image; and

adjusting the camera to be centered to an optical center of the camera during zooming based on the determined offsets.

4. A method as recited in claim 3 wherein adjusting the camera comprises interpolating the offset based on the magnification factor and the determined offsets.

5. A method as recited in claim 1 wherein comparing the third image with the second image comprises choosing a block from the third image containing at least a portion of the object and comparing it to blocks from the second image to determine a block with a minimal block distance.

6. A method as recited in claim 1 wherein adjusting the camera comprises adjusting the position of the camera.

7. A method as recited in claim 1 wherein adjusting the camera comprises adjusting the position of the image sensor of the camera.

8. A system for centering an object in the field of view of a camera comprising:

a camera having a lens with a variable zoom; a lens controller connected to the lens to vary the zoom of the lens; an image sensor, the lens being positioned to provide light rays to the image sensor; an input for receiving an instruction to change the zoom of the lens; a position controller for moving the camera; and

a processor in communication with the camera to provide signals to the camera and to receive images captured by the camera, the processor being adapted to:

provide a signal to the lens controller to set the lens zoom to a first magnification factor to configure the lens to have a first field of view;

provide a signal to the position controller to position the camera to have an object in a first position in the first field of view;

provide a signal to the camera to capture a first image with the camera at the first magnification factor;

provide a signal to set the camera zoom to a second magnification factor to configure the camera to have a second field of view with the second magnification factor being greater than the first magnification factor;

provide a signal to the camera to capture a second image with the camera at the second magnification factor;

receive the first image from the camera;

digitally alter a portion of the first image to create a third image with a magnification factor equivalent to the second magnification factor;

receive the second image;

compare the third image with the second image to determine an offset of the object from the first position of the object to the position of the object in the third image; and

provide a signal to the position controller to adjust the camera to be centered to an optical center of the camera during zooming based on the offset.

9. A system as recited in claim 8 wherein the processor is adapted to generate a signal to the position controller to position the camera to center the object in the first field of view.

10. A system as recited in claim 8 wherein the processor is adapted to:

generate a signal to the camera to capture a fourth image at a third magnification factor;

digitally alter a portion of the first image to create a fifth image with a magnification factor equivalent to the third magnification factor;

receive the fourth image;

compare the fifth image with the fourth image to determine an offset of the object from the first position of the object to the position of the object in the fourth image; and

provide a signal to the position controller to adjust the camera to be centered to an optical center of the camera during zooming based on the determined offsets.

11. A system as recited in claim 10 wherein the processor is adapted to provide a signal to the position controller to adjust the camera position based on interpolating the offset based on the magnification factor and the determined offsets.

12. A non-transitory computer readable medium comprising instructions configured to cause a processor to:

set a camera zoom to a first magnification factor to configure the camera to have a first field of view;

position the camera to have an object in a first position in the first field of view;

capture a first image with the camera at the first magnification factor;

set the camera zoom to a second magnification factor to configure the camera to have a second field of view with the second magnification factor being greater than the first magnification factor;

capture a second image with the camera at the second magnification factor;

digitally alter a portion of the first image to create a third image with a magnification factor equivalent to the second magnification factor;

compare the third image with the second image to determine an offset of the object from the first position of the object to the position of the object in the third image; and

adjust the camera to be centered to an optical center of the camera during zooming based on the determined offset.

13. A non-transitory computer readable medium as recited in claim 12 wherein positioning the camera to have an object in a first position in the first field of view comprises causing the processor to position the camera to center the object in the first field of view.

14. A non-transitory computer readable medium as recited in claim 12 further comprising instructions configured to cause the processor to:

capture a fourth image with the camera at a third magnification factor;

digitally alter a portion of the first image to create a fifth image with a magnification factor equivalent to the third magnification factor;

compare the fifth image with the fourth image to determine an offset of the object from the first position of the object to the position of the object in the fourth image; and

adjust the camera to be centered to an optical center of the camera during zooming based on the determined offsets.

15. A non-transitory computer readable medium as recited in claim 12 wherein adjusting the camera comprises causing the processor to interpolate the offset based on the magnification factor and the determined offsets.

16. A non-transitory computer readable medium as recited in claim 12 wherein comparing the third image with the second image comprises causing the processor to choose a block from the third image containing at least a portion of the object and compare it to blocks from the second image to determine a block that has a minimal block distance.

17. A non-transitory computer readable medium as recited in claim 12 wherein adjusting the camera comprises causing the processor to adjust the position of the camera.

18. The method as recited in claim 1 wherein:

the digitally altered portion of the first image is a central portion; and

comparing the third image with the second image to determine the offset comprises comparing a central portion of the third image with a central portion of the second image.

19. The system as recited in claim 8 wherein the processor is further adapted to:

digitally alter a central portion of the first image to create the third image; and

compare a central portion of the third image with a central portion of the second image to determine the offset of the object from the first position of the object to the position of the object in the third image.

20. A non-transitory computer readable medium as recited in claim 12 wherein:

the digitally altered portion of the first image is a central portion; and

comparing the third image with the second image to determine the offset comprises comparing a central portion of the third image with a central portion of the second image.