Image capture device having tilt and/or perspective correction

• US 8,687,070 B2
• Filed: 12/22/2009
• Issued: 04/01/2014
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chen, Jason Hau-Ping, Slack, Brandon Dean, Simon, David I.
• Primary Examiner(s): NGUYEN, LUONG TRUNG
• Application Number:
  US12/644,800
• Publication Number:
  US 20110149094A1
• Time in Patent Office: 1,561 Days
• Field of Search: None
• US Class Current: 348/208.3
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6815 by distinguishing pan or tilt from motion

Abstract

Methods and apparatuses are disclosed to correct for tilt and/or perspective distortion in image capture devices. In some embodiments, the method may include reading an orientation measurement associated with a relative position of an image capture device with respect to an object, determining if the orientation measurement is less than a threshold, and in the event that the orientation measurement is less than the threshold, correcting an image obtained by the image capture device. In some embodiments, the apparatus may include an image sensor, a memory coupled to the image sensor, an orientation measurement device coupled to the image sensor, and a distance measurement device coupled to the image sensor, where the image data may be stored in the memory along with a measurement from the accelerometer and along with a measurement from the distance measurement device.

Claims

1. A method of compensating for image distortion comprising the acts of:

reading an orientation measurement of an image capture device during a capture of an image, the image comprising image data;

determining an orientation of one or more straight edges in the image;

determining a difference between the orientation measurement of the image capture device and the orientation of the one or more straight edges; and

correcting the image by modifying the image data if the difference is less than a threshold.

2. The method of claim 1, further comprising the act of storing the image in a memory.

3. The method of claim 2, wherein the act of correcting the image occurs prior to the act of storing the image.

4. The method of claim 3, wherein the act of correcting the image occurs on-the-fly.

5. The method of claim 2, further comprising the act of displaying the corrected image on a display prior to the act of storing the image.

6. The method of claim 1, further comprising the act of displaying a distortion indicator on a display along with the image, wherein the distortion indicator is related to the orientation measurement of the image capture device.

7. The method of claim 1, wherein the act of correcting the image includes compensating for distortion of the image along at least one of a X axis, a Y axis, or a Z axis.

8. The method of claim 7, wherein the act of determining the difference includes determining a difference between the measured orientation of the image capture device and the orientation of the one or more straight edges in at least two of the X, Y, and Z axes.

9. A non-transitory program storage device, readable by a processor and comprising instructions stored thereon to cause one or more processors to:

obtain an orientation measurement of an image capture device during an image capture operation, wherein a captured image comprises data representative of a scene;

identify one or more straight edges in the data corresponding straight edges in the scene;

determine a difference based, at least in part, on the measured orientation of the image capture device and an orientation of at least one of the one or more straight edges in the data; and

modify the data when the difference is less than a threshold value.

10. The non-transitory program storage device of claim 9, wherein the instructions to cause the one or more processors to obtain the orientation measurement of the image capture device comprise instructions to cause the one or more processors to obtain the orientation measurement of the image capture device along each of one or more axes relative to the image capture device.

11. The non-transitory program storage device of claim 10, wherein the instructions to cause the one or more processors to determine the difference comprise instructions to cause the one or more processors to determine the difference based, at least in part, on the measured orientation of the image capture device along a first axis of the axes and an orientation of at least one of the one or more straight edges in the data along the first axis.

12. The non-transitory program storage device of claim 11, wherein the instructions to cause the one or more processors to determine the difference further comprise instructions to cause the one or more processors to determine an angular difference between the measured orientation of the image capture device along the first axis and the orientation of the at least one of the one or more straight edges in the data along the first axis.

13. The non-transitory program storage device of claim 10, wherein the instructions to cause the one or more processors to modify the data comprise instructions to cause the one or more processors to modify the data so that the orientation of the at least one of the one or more straight edges in the data is aligned with the measured orientation of the image capture device.

14. The non-transitory program storage device of claim 10, wherein the instructions to cause the one or more processors to modify the data comprise instructions to cause the one or more processors to modify the data so that the orientation of the at least one of the one or more straight edges in the data is aligned near but not exactly with the measured orientation of the image capture device.

15. The non-transitory program storage device of claim 10, wherein the instructions to cause the one or more processors to determine the difference comprise instructions to cause the one or more processors to:

determine a first angular difference between an orientation of a first of the one or more straight edges in the data and the measured orientation of the image capture device along a first of the one or more axes; and

determine a second angular difference between an orientation of the first straight edge and the measured orientation of the image capture device along a second of the one or more axes.

16. The non-transitory program storage device of claim 15, wherein the instructions to cause the one or more processors to modify the data comprise instructions to cause the one or more processors to:

modify the data so that the orientation of the first straight edge is aligned with the measured orientation of the image capture device along the first axis based on, at least in part, the first angular difference; and

modify the data so that the orientation of the first straight edge is aligned with the measured orientation of the image capture device along the second axis based on, at least in part, the second angular difference.

17. The non-transitory program storage device of claim 9, further comprising instructions to cause the one or more processors to display the image and a distortion indication on a display, wherein the distortion indication is related to the measured orientation of the image capture device.

18. The non-transitory program storage device of claim 9, further comprising instructions to cause the one or more processors to store the measured orientation of the image capture device in a header region of a file in which the data is also stored.

19. The non-transitory program storage device of claim 9, wherein the instructions to cause the one or more processors to modify the data comprise instructions to cause the one or more processors to modify the data on-the-fly.