Automatic correction of keystone distortion and other unwanted artifacts in projected images

• US 9,667,932 B2
• Filed: 04/27/2011
• Issued: 05/30/2017
• Est. Priority Date: 02/03/2011
• Status: Active Grant

• Current Assignee: Videa, L.L.C.
• Original Assignee: Videa, L.L.C.
• Inventors: Posa, John G., Schwab, Barry H.
• Primary Examiner(s): Craddock, Robert
• Application Number:
  US13/095,569
• Publication Number:
  US 20120200588A1
• Time in Patent Office: 2,225 Days
• Field of Search: 345589
• CPC Class Codes: G09G 2320/06 Adjustment of display parameters
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20
• CPC Class Codes: H04N 9/3185 Geometric adjustment, e.g. keystone or convergence optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/3194 including sensor feedback

Abstract

A system for manual or automatic correction of geometric or video image distortions introduced by projection onto obliquely angled or imperfect surfaces. Sensors may be disposed at the projector itself, at the projected image surface, or in a portable remote-control unit. Corrections may be applied as part of an original set-up process, or dynamically as the configuration changes. Image-stabilization techniques are utilized where applicable, as is the use of test patterns and the incorporation of “helper” signals into the video image. Tactile-sensing capabilities provide an interactive environment, and various packaging configurations for projection units and sensor provisions are disclosed.

Claims

1. Projected image correction apparatus, comprising:

a device including a display processor and a projector operative to project an image defining a display area onto a surface;

a sensor operative to view the projected image on the surface;

a display buffer storing a raw image to be seen by a viewer;

a projection buffer storing a version of the raw image to be projected onto the surface;

a sensor buffer storing an image of the projected image as viewed by the sensor; and

wherein the display processor is operative to compare the image stored in the sensor buffer to the image stored in the display buffer and adjust the image stored in the projection buffer so that the projected image seen by the sensor corresponds to the image stored in the display buffer;

wherein the sensor is operative to view an area of the surface which is larger than the display area of the projected image and store an image of the larger area in the sensor buffer; and

wherein, in comparing the image stored in the sensor buffer to the image stored in the display buffer, the display processor is operative to determine if the projected image has shifted and intentionally shift the image in the projection buffer to correct for defects in the projected image including motion artifacts caused by movement of the device.

2. The apparatus of claim 1, wherein:

the device is a video projector; and

the projector is operative to project a video image onto the surface.

3. The apparatus of claim 1, wherein the device is a portable computer.

4. The apparatus of claim 1, wherein the device is a smart phone.

5. The apparatus of claim 1, wherein the device is a camcorder.

6. The apparatus of claim 1, wherein the sensor is a two-dimensional image sensor.

7. The apparatus of claim 1, wherein the sensor is disposed in the device.

8. The apparatus of claim 1, wherein:

the sensor is disposed in a hand-held remote unit operative to control certain functions of the device; and

the hand-held remote unit communicates the information to the device through a wireless connection.

9. The apparatus of claim 1, wherein the correction occurs in conjunction with an initial projection.

10. The apparatus of claim 1, wherein the correction occurs in response to a user input.

11. The apparatus of claim 1, wherein the correction automatically occurs on an occasional or continuous basis.

12. The apparatus of claim 1, wherein the display generator is further operative to generate a test pattern to be viewed by the sensor for correction purposes.

13. The apparatus of claim 1, wherein the device includes a detachable or roll-out display screen providing the surface.

14. The apparatus of claim 1, further including:

a display screen providing the surface; and

wherein;

the display screen includes corner or edge indicia to assist the sensor in determining the periphery thereof.

15. The apparatus of claim 1, wherein the display processor is operative to perform one or more of the following adjustments to the image stored in the projection buffer:

flipping,

stretching,

luminance or color curve adjustment,

color replacement,

pixel interpolation, and

rotation.

16. The apparatus of claim 1, further including:

gesture recognition apparatus operative to recognize a gesture made by a finger, hand or other body part overlying the projected image in the view of the sensor; and

control the device or projected image in response to the recognized gesture.

17. The apparatus of claim 1, wherein:

the projected image has x and y coordinates associated therewith; and

gesture recognition apparatus operative to determine the coordinates of a finger, hand or other body part overlying the projected image in the view of the sensor; and

apparatus operative to compare the position or movement thereof a finger, hand or other body part overlying the projected image to corresponding coordinates associated with the projected image to control the device or the projected image.

18. The apparatus of claim 1, wherein:

the projected image has x and y coordinates associated therewith;

the sensor includes an infrared imaging capability operative to detect a finger, hand or other body part overlying the projected image; and

gesture recognition apparatus operative to determine the coordinates of the finger, hand or other body part detected by the sensor; and

apparatus operative to compare the position or movement thereof a finger, hand or other body part overlying the projected image to corresponding coordinates associated with the projected image to control the device or the projected image.

19. The apparatus of claim 1, wherein:

the projected image has x and y coordinates associated therewith;

further including a tactile sensor operative to generate a wireless signal if a point of the surface is touched by a user;

a wireless receiver operative to receive the wireless signal; and

apparatus operative to receive the image viewed by the sensor, determine the coordinates of the point touched by the user in response to receipt of the wireless signal, and compare the coordinates to the coordinates of the projected image to select a region of the projected image associated with the point.

20. The apparatus of claim 19, wherein:

the wireless signal is an optical signal; and

the sensor is operative to detect the optical signal.

21. The apparatus of claim 19, wherein:

the wireless signal is an infrared signal; and

the sensor is operative to detect the infrared signal.

22. The apparatus of claim 19, wherein:

the wireless signal is an RF signal.

23. The apparatus of claim 1, wherein, in an event the display processor is unable to compensate for the motion, the projection buffer is selectively turned off or a frame rate is reduced to facilitate movement compensation.