Projector pen image stabilization system

• US 20050280628A1
• Filed: 05/11/2005
• Published: 12/22/2005
• Est. Priority Date: 05/12/2004
• Status: Abandoned Application

• Current Assignee: Northrop Grumman Corporation
• Original Assignee: Northrop Grumman Corporation
• Inventors: Nathanson, Harvey C., Storaska, Garrett A., Howell, Robert S., Hall, William E., Adams, Charles R.
• Application Number:
  US11/126,255
• Publication Number:
  US 20050280628A1
• Time in Patent Office: Days
• US Class Current: 345/156
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• 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 high resolution pen-sized projector for controlling the position and size of an image generated by a closed loop control system consists of four major system components including: a virtual VGA display located inside of a XGA display, a position acquisition system, a displacement compensating control system to determine correct position of the VGA display inside of the XGA display, and a dark display area of the background portion of the XGA display.

Claims

1. An image stabilization system for a portable image projector comprising:

a portable housing;

an image projector located in the housing for generating a visual image which is projected through a lens in the housing onto an external viewing medium, said image comprising a composite image including a first image located within and movable in a second image;

an image acquisition device located in the housing adjacent the lens for sensing the projected image and generating electrical signals corresponding to said first and second images;

a signal processor connected to the image acquisition device for generating a video frame signal of the projected image, said processor being operable to determine the area and boundaries of the first image and compensating for any displacement thereof from an initial position in said second image;

a memory connected to the signal processor for storing the video frame signals of a predetermined number of consecutive video frame signals of the sensed image; and

a video signal generator connected between the memory and the image projector for generating an image signal of the last video frame signal so as to reposition the first image within the second image in the event of any movement of the first image relative to the second image.

2. The system of claim 1 wherein the portable housing comprises a device adapted to be held in the hand of a user.

3. The system of claim 2 wherein the device is in the shape and size of a pocket pen.

4. The system of claim 1 wherein the first image has an image resolution less than the image resolution of the second image.

5. The system of claim 4 wherein the first image has a VGA image resolution and a second image has a XGA image resolution.

6. The system of claim 5 wherein the color of the second image is dark relative to the color of the first image.

7. The system of claim 5 wherein the color of the second image is set so as to be substantially black.

8. The system of claim 4 wherein the image projector includes a MEMS mirror chip for projecting the image on an external surface.

9. The system of claim 4 wherein the image acquisition device includes a charge coupled device (CCD) array for sensing the projected image.

10. The system of claim 4 wherein the projected size of the first image is varied by changing the image resolution or zooming the first image.

11. The system of claim 5 wherein the first image is provided with one or more elements for enabling determination of the boundaries of the first image.

12. The system of claim 11 wherein said one or more elements comprises elements selectively located on the periphery of the first image.

13. The system of claim 11 wherein said one or more elements comprise elements located in the corner regions of the first image.

14. The system of claim 11 wherein said one or more elements comprises light emitting diodes located at selected points of the first image.

15. The system of claim 14 wherein said light emitting diodes comprise infra-red diodes.

16. The system of claim 11 wherein said one or more elements comprise a target element selectively located in the first image.

17. The system of claim 16 wherein the target element is located substantially at the center of the first image.

18. A method of stabilizing a projected visual display, comprising the steps of:

sensing the projected visual display and generating electrical signals corresponding to the sensed display;

processing the sensed display by generating a video frame signal of the sensed display, determining the size, area and boundaries of at least one portion of the display and compensating for any displacement of said one portion of the display;

storing the video frame signals of a predetermined number of consecutive video frame signals; and

generating a display signal of the last video frame signal so as to reposition said one portion of the display in the event of any movement thereof.

19. The method of claim 18 wherein said at least one portion of the display comprises a first image located within a second image.

20. The method of claim 19 wherein the first image has an image resolution less than the image resolution of the second image.

21. The method of claim 20 wherein the first image has a VGA resolution and the second image has an XGA image resolution.

22. The method of claim 21 wherein the second image provides a background for the first image and is darker in color than said first image.

23. The method of claim 22 wherein the first image is geometrical in shape and includes one or more elements for determining the boundaries of the first image.

24. The method of claim 23 wherein said elements comprise light emitting elements.

25. The method of claim 24 wherein said light emitting elements comprise light emitting diodes including infra-red diodes.

26. The method of claim 18 wherein the display is generated by a portable hand-held image projector.

27. The method of claim 26 wherein the hand-held image projector is in the shape and size of a pocket pen.