COMPENSATING ANGULAR MISALIGNMENT IN OPTICAL IMAGE STABILIZATION (OIS) SYSTEMS

• US 20160088214A1
• Filed: 09/10/2015
• Published: 03/24/2016
• Est. Priority Date: 09/23/2014
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Karttunen, Juha Jorma Sakari, Tikkanen, Jussi Petteri
• Granted Patent: US 10,038,850 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/685 performed by mechanical compensation

Abstract

Systems and methods for compensating angular misalignment in Optical Image Stabilization (OIS) systems are described. In some embodiments, a method may include measuring an angle representing a misalignment between an actuator and an electronic component within a camera; and compensating for the misalignment using a rotation matrix, wherein the rotation matrix is calculated based upon the angle. In other embodiments, a camera may include an image sensor coupled to a Printed Circuit Board (PCB); an OIS actuator coupled to the PCB and optically coupled to the image sensor, where the OIS actuator is physically misaligned with respect to the image sensor; and a controller coupled to the PCB, the controller configured to: measure an angle representing the misalignment; and compensate for the misalignment using a rotation matrix at the time of an image capture, where the rotation matrix is calculated based upon the angle.

Claims

1. A method, comprising:

measuring an angle representing a misalignment between an actuator and an electronic component within a camera; and

compensating for the misalignment using a rotation matrix, wherein the rotation matrix is calculated based upon the angle.

2. The method of claim 1, wherein the electronic component is a gyroscope.

3. The method of claim 1, wherein the electronic component is an image sensor optically coupled to the actuator.

4. The method of claim 3, wherein the actuator comprises at least one of:

an Optical Image Stabilization (OIS) actuator or an Auto-Focus (AF) actuator.

5. The method of claim 3, wherein compensating for the misalignment comprises, in connection with an Optical Image Stabilization (OIS) operation, applying the rotation matrix to correct a lens target position at the time of an image capture.

6. The method of claim 1, wherein measuring the angle further comprises:

moving the actuator to a first position along a given axis;

capturing a first image;

moving the actuator to a second position along the given axis;

capturing a second image; and

comparing the second image with the first image.

7. The method of claim 4, wherein comparing the second image with the first image further comprises:

determining a first distance between a pixel in the first image and a corresponding pixel in the second image along the given axis;

determining a second distance between the pixel and the corresponding pixel in a direction perpendicular to the given axis; and

calculating the angle based upon the first and second distances.

8. The method of claim 7, wherein the angle is given by θ

, the first distance is given by d₁, the second distance is given by d₂, and calculating the angle comprises calculating;

9. The method of claim 8, wherein the rotation matrix (R) is given by:

10. A camera comprising:

an image sensor coupled to a Printed Circuit Board (PCB);

an Optical Image Stabilization (OIS) actuator coupled to the PCB and optically coupled to the image sensor, wherein the OIS actuator is physically misaligned with respect to the image sensor; and

a controller coupled to the PCB, the controller configured to;

measure an angle representing the misalignment; and

compensate for the misalignment using a rotation matrix at the time of an image capture, wherein the rotation matrix is calculated based upon the angle.

11. The camera of claim 10, wherein to compensate for the misalignment, the controller is further configured to, in connection with an Optical Image Stabilization (OIS) operation, apply the rotation matrix to correct a lens target position calculated by the controller.

12. The camera of claim 10, wherein to measure the angle representing the misalignment, the controller is further configured to:

move the OIS actuator to a first position along an axis;

capture a first image;

move the OIS actuator to a second position along the axis;

capture a second image; and

compare the second image with the first image.

13. The camera of claim 12, wherein to compare the second image with the first image, the controller is further configured to:

determine a first distance between a pixel in the first image and a corresponding pixel in the second image along the axis;

determine a second distance between the pixel and the corresponding pixel in a direction perpendicular to the axis; and

calculate the angle based upon the first and second distances.

14. The camera of claim 13, wherein the angle is given by θ

, the first distance is given by d₁, the second distance is given by d₂, and the controller is configured to calculate;

15. The camera of claim 14, wherein the rotation matrix (R) is given by:

16. A memory device having program instructions stored thereon that, upon execution by a processor within a camera, cause the camera to:

apply a rotation matrix to a lens target position calculated by an Optical Image Stabilization (OIS) controller as part of an OIS operation to result in a corrected lens target position;

provide the corrected lens target position to an OIS actuator coupled to lens; and

obtain an image from an image sensor optically coupled to the lens, wherein the corrected lens target position compensates for an angular misalignment between an OIS actuator and a gyroscope.

17. The memory device of claim 16, wherein the program instructions, upon execution by the processor, further cause the camera to, prior to obtaining the image:

move the OIS actuator to a first position along an axis;

capture a first image;

move the OIS actuator to a second position along the axis;

capture a second image; and

compare the second image with the first image.

18. The memory device of claim 17, wherein to compare the second image with the first image, the program instructions, upon execution by the processor, further cause the camera to:

determine a first distance between a pixel in the first image and a corresponding pixel in the second image along the axis;

determine a second distance between the pixel and the corresponding pixel in a direction perpendicular to the axis; and

calculate the angle based upon the first and second distances.

19. The memory device of claim 18, wherein the angle is given by θ

, the first distance is given by d₁, the second distance is given by d₂, and the controller is configured to calculate;

20. The memory device of claim 19, wherein the rotation matrix (R) is given by: