Image stabilization method and apparatus

• US 8,159,541 B2
• Filed: 03/24/2008
• Issued: 04/17/2012
• Est. Priority Date: 04/16/2007
• Status: Active Grant

• Current Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Original Assignee: STMicroelectronics Limited (STMicroelectronics NV)
• Inventors: McLeod, Stuart
• Primary Examiner(s): VU, NGOC YEN T
• Application Number:
  US12/053,744
• Publication Number:
  US 20080252736A1
• Time in Patent Office: 1,485 Days
• Field of Search: 348/208.2, 348/208.7
• US Class Current: 348/208.2
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof

Abstract

An image stabilization apparatus includes accelerometers, a proximity sensor and a processor. Each accelerometer determines acceleration along an axis of a plane parallel to a focal plane of an image capture device. The accelerometers output respective acceleration data to the processor. The proximity sensor obtains a measurement of the distance between the focal plane of the image capture device and an object plane. The proximity sensor outputs distance data to the processor. The processor processes the distance data and the acceleration data to produce correction data to correct image data captured during motion of the image capture device.

Claims

1. An image stabilization apparatus comprising:

a plurality of accelerometers to determine acceleration along axes of a plane parallel to a focal plane of an image capture device, with at least two of the axes inclined with respect to each other, and each accelerometer to output respective acceleration data;

an infra-red (IR) proximity sensor to measure a distance between the focal plane of the image capture device and an object plane corresponding to image data to be captured by the image capture device, and to output distance data; and

a processor to process the respective acceleration data from said plurality of accelerometers and the distance data from said (IR) proximity sensor to generate correction data to correct the image data captured during motion of the image capture device, with the correction data being used to

compensate for a calculated offset between a desired and an actual center of a focal point of the image capture device, and

determine an angular motion of the image capture device to reduce an effect of rotation on a gravity vector in the respective acceleration data.

2. The image stabilization apparatus according to claim 1 wherein at least one of said plurality of accelerometers comprises a linear accelerometer.

3. The image stabilization apparatus according to claim 1 wherein at least one of said plurality of accelerometers comprises a microelectromechanical systems (MEMS) accelerometer.

4. The image stabilization apparatus according to claim 1 wherein said plurality of accelerometers is arranged in an L-shaped configuration.

5. The image stabilization apparatus according to claim 1 wherein said plurality of accelerometers is arranged in a T-shaped configuration.

6. The image stabilization apparatus according to claim 5 wherein the T-shaped configuration has a common axis between two accelerometers of said plurality of accelerometers;

and said image capture device is at a mid-point with respect to the common axis.

7. The image stabilization apparatus according to claim 6 wherein said processor calculates a vector difference between the respective acceleration data received from the two accelerometers along the common axis.

8. The image stabilization apparatus according to claim 7 wherein said processor calculates linear displacement data corresponding to linear displacement of said image capture device associated with the vector difference in acceleration.

9. The image stabilization apparatus according to claim 8 wherein said processor uses the linear displacement data when producing the correction data.

10. The image stabilization apparatus according to claim 1 wherein said processor samples said plurality of accelerometers and said proximity sensor at a frequency >

40 Hz.

11. The image stabilization apparatus according to claim 1 further comprising an image coprocessor to apply the correction data to the captured image data.

12. The image stabilization apparatus according to claim 1 further comprising a displacement device to displace the image capture device based on the acceleration data.

13. An imaging system comprising:

an image capture device to capture image data, and having a focal plane associated therewith;

an image sensor stack comprising a focus unit to focus the image data onto said image capture device; and

an image stabilization apparatus to stabilize the captured image data during motion of said image capture device, said image stabilization apparatus comprising

a plurality of accelerometers to determine acceleration along axes of a plane parallel to the focal plane of said image capture device, and each accelerometer to output respective acceleration data,

a proximity sensor comprising an output from said focus unit to measure a distance between the focal plane of said image capture device and an object plane corresponding to the captured image data, and to output distance data, and

a processor to process the respective acceleration data from said plurality of accelerometers and the distance data from said proximity sensor to generate correction data, with the correction data being used to

move said image sensor stack to compensate for a calculated offset between a desired and an actual center of the focal point of said image capture device, and

determine an angular motion of said image capture device to reduce an effect of rotation on a gravity vector in the respective acceleration data.

14. The imaging system according to claim 13 wherein at least one of said plurality of accelerometers is on said image capture device.

15. The imaging system according to claim 13 further comprising a mechanical correction device;

and wherein said processor controls said mechanical correction device based on the correction data.

16. The imaging system according to claim 15 wherein said image capture device comprises a lens:

and wherein said mechanical correction device moves said lens based on the correction data.

17. The imaging system according to claim 13 further comprising a coprocessor to receive the correction data from said processor, with said coprocessor to apply the correction data to the captured image data.

18. The imaging system according to claim 13 wherein at least one of said plurality of accelerometers comprises a linear accelerometer.

19. The imaging system according to claim 13 wherein said plurality of accelerometers is arranged in an L-shaped configuration.

20. The imaging system according to claim 13 wherein said plurality of accelerometers is arranged in a T-shaped configuration.

21. The imaging system according to claim 13 wherein said image capture device and said image stabilization apparatus are configured so that the imaging system is at least one of a digital still camera, a digital video camera, a web-cam, a mobile telephone and a personal digital assistant.

22. A method for stabilizing an image captured by an image capture device using an image stabilization apparatus, the image stabilization apparatus comprising a plurality of accelerometers, an infra-red (IR) proximity sensor and a processor, the method comprising:

generating respective acceleration data via the plurality of accelerometers along axes of a plane parallel to a focal plane of the image capture device, with at least two of the axes inclined with respect to each other;

generating distance data via the (IR) proximity sensor between the focal plane of the image capture device and an object plane corresponding to image data captured by the image capture device; and

generating correction data via the processor to correct the captured image data captured during motion of the image capture device based on processing the respective acceleration data from the plurality of accelerometers and the distance data from the (IR) proximity sensor, with the correction data being used to

compensate for a calculated offset between a desired and an actual center of a focal point of the image capture device, and

determine an angular motion of the image capture device to reduce an effect of rotation on a gravity vector in the respective acceleration data.

23. The method according to claim 22 wherein at least one of the plurality of accelerometers comprises a linear accelerometer.

24. The method according to claim 23 wherein the plurality of accelerometers is arranged in an L-shaped configuration.

25. The method according to claim 23 wherein the plurality of accelerometers is arranged in a T-shaped configuration.

26. The method according to claim 25 wherein the T-shaped configuration has a common axis between two accelerometers of the plurality of accelerometers;

and the image capture device is at a mid-point with respect to the common axis; and

wherein

the processor calculates a vector difference between the respective acceleration data received from the two accelerometers along the common axis.

27. The method according to claim 26 wherein the processor calculates linear displacement data corresponding to linear displacement of the image capture device associated with the vector difference in acceleration.