METHOD AND APPARATUS FOR DEPTH SENSING KEYSTONING

• US 20100061659A1
• Filed: 09/08/2008
• Published: 03/11/2010
• Est. Priority Date: 09/08/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Medeiros, Jason, Leiba, Aaron, Slack, Brandon Dean, Crumlin, Alex J.
• Granted Patent: US 8,538,084 B2
• Time in Patent Office: Days
• US Class Current: 382/295
• 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 the surface, using a first measurement device to measure the first distance;

measuring a second distance between the image projection system and the surface, using a second measurement device to measure the second distance;

calculating a horizontal slope of the surface with respect to a projection path of the image projection system;

creating a transform using at least the horizontal slope and the vertical slope; and

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

2. The method of claim 1, further comprising the operations of:

calculating a vertical slope of the surface with respect to the projection path of the image projection system; and

creating the transform using at least the vertical slope.

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

using the trigonometric function to calculate a second angle; and

using at least the second angle to create the transform.

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

using a trigonometric function to calculate a first angle; and

using at least the first angle to create the transform.

5. 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.

6. The method of claim 1, wherein the operation of using the first and second measurement devices further comprises using at least the first measurement device and a second measurement device located adjacent to a lens of the image projection system.

7. 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.

8. The method of claim 1, further comprising using additional depth sensors located on the image projection system wherein the additional depth sensors are oriented downwardly.

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

10. The method of claim 8, further comprising accounting for the yaw of the image projection system using the additional depth sensors.

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

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

13. A computer-implemented method for calibrating an image projection system, comprising:

capturing at least a first image and a second image using at least a camera;

determining a first set of points from the first image using at least the computer system;

determining a second set of points from the second image using at least the computer system;

creating a first transform using the computer system, the first transform mapping the first set of points to a third set of points on a third image;

creating a second transform using the computer system, the second transform mapping the second set of points to a fourth set of points on a fourth image;

creating a final transform using the computer system, using the first transform and an inverted second transform; and

applying an inverted final transform to the third image, using the computer system to apply the inverted final transform.

14. The method of claim 13, wherein the first image is an image of a projected image on a projection surface and the second image is an image of a projection surface, further wherein the first set of points includes the corners of the projected image on the projection surface and the second set of points includes the corners of the projection surface.

15. The method of claim 13, wherein the third set of points includes the corners of the raw image.

16. The method of claim 13, wherein the second set of points is substituted for the fourth set of points.

17. The method of claim 13, wherein creating the first transform further comprises using the equation (a, b)=M(X, Y), wherein (X,Y) is the first set of points, (a,b) is the second set of points and M is the first transform.

18. The method of claim 17, further comprising using the least squares method to calculate the first transform M.

19. An image processing system comprising:

a plurality of sensors operative to perform at least depth measurements;

an image processor operative to at least receive depth measurements from the plurality of sensors and to calculate image transforms; and

an image projection system operative to project at least a first image.

20. The system of claim 19, wherein the plurality of sensors are infrared sensors that are operative to perform at least depth measurements.

21. The system of claim 19, further comprising a camera, wherein the camera includes a plurality of camera pixels, each pixel being a depth sensor.