Method and apparatus for depth sensing keystoning

• US 8,538,084 B2
• Filed: 09/08/2008
• Issued: 09/17/2013
• Est. Priority Date: 09/08/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Slack, Brandon Dean, Leiba, Aaron, Crumlin, Alex J., Medeiros, Jason
• Primary Examiner(s): Liew, Alex
• Application Number:
  US12/206,554
• Publication Number:
  US 20100061659A1
• Time in Patent Office: 1,835 Days
• Field of Search: 382/106, 382/154
• US Class Current: 382/106
• CPC Class Codes: G06V 10/245 by locating a pattern; Special marks for positioning

Abstract

A method for depth sensing keystoning. The method of depth sensing keystoning may include an optical system and electrical devices. The method of depth sensing keystoning may correct for image distortion using depth measurements.

Claims

1. A computer-implemented method for correcting image distortion in an image projected on a surface comprising the operations of:

measuring a first distance between an image projection system and a surface using a first measurement device;

measuring a second distance between the image projection system and the surface using a second measurement device spatially separated from the first measurement device;

calculating a first slope of the surface with respect to a projection path of the image projection system, the first slope corresponding to a first angular offset of the surface with respect to the image projection system;

calculating a second slope of the surface with respect to the projection path of the image projection system, the second slope corresponding to a second angular offset of the surface with respect to the image projection system;

creating a transform using at least the first slope and the second slope; and

applying the transform to a first image, thereby creating a second image.

2. The method of claim 1, wherein the operation of creating the transform using the second slope further comprises:

using a trigonometric function to calculate a second angle; and

using at least the second angle to create the transform.

3. The method of claim 1, wherein the operation of creating the transform using the first slope further comprises:

using a trigonometric function to calculate a first angle; and

using at least the first angle to create the transform.

4. The method of claim 1, wherein the operation of using the first measurement device to measure the first distance further comprises using a depth sensor.

5. The method of claim 1, wherein the first measurement device is located on a first side and adjacent to a lens of the image projection system and the second measurement device is located on a second side and adjacent to the lens of the image projection system.

6. The method of claim 1, further comprising using an accelerometer located on the image projection system to compensate for at least a yaw of the image projection system.

7. The method of claim 4, further comprising using additional depth sensors located on the image projection system wherein the additional depth sensors are oriented downwardly.

8. The method of claim 7, further comprising accounting for a pitch of the image projection system using the additional depth sensors.

9. The method of claim 7, further comprising accounting for the yaw of the image projection system using the additional depth sensors.

10. The method of claim 1, further comprising measuring a plurality of distances using a camera where each pixel is a depth sensor.

11. The method of claim 1, further comprising using at least one infrared sensor to output and detect selected infrared signals.

12. A non-transitory computer readable medium, readable by a computer processor and having instructions stored thereon for causing one or more processors to:

obtain a measure of a first distance between an image projection system and a surface using a first measurement device;

obtain a measure of a second distance between the image projection system and the surface using a second measurement device that is spatially separated from the first measurement device;

calculate a first slope of the surface with respect to a projection path of the image projection system, the first slope corresponding to a first angular offset of the surface with respect to the image projection system;

calculate a second slope of the surface with respect to the projection path of the image projection system, the second slope corresponding to a second angular offset of the surface with respect to the image projection system;

create a transform based, at least in part, on the first and second slopes; and

apply the transform to a first image to create a second image.

13. The non-transitory computer readable medium of claim 12, wherein the instructions to create a transform comprise instructions to cause the one or more processors to:

use a trigonometric function to calculate a first angle of the first slope; and

use at least the first angle to create the transform.

14. The non-transitory computer readable medium of claim 12, wherein the instructions to create a transform comprise instructions to cause the one or more processors to:

use a trigonometric function to calculate a second angle of the second slope; and

use at least the second angle to create the transform.

15. The non-transitory computer readable medium of claim 12, wherein the instructions to obtain a measure of a first distance comprise instructions to use a depth sensor.

16. The non-transitory computer readable medium of claim 15, further comprising instructions to cause the one or more processors to use additional depth sensors to create the transform, wherein the additional depth sensors are located on the image projection system in a downward orientation.