Calibration of an interactive desktop system

• US 6,005,547 A
• Filed: 09/13/1996
• Issued: 12/21/1999
• Est. Priority Date: 10/14/1995
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Fraser, Quentin Stafford, Bentley, Richard M., Newman, William M.
• Primary Examiner(s): Luu, Matthew
• Assistant Examiner(s): PIZIALI, JEFFREY J
• Application Number:
  US08/713,490
• Time in Patent Office: 1,194 Days
• Field of Search: 345/1, 345/113-115, 345/156-158, 345/173-178, 395/333, 358/93, 358/471, 358/464, 358/475, 350/208.1, 350/222.1, 364/552, 382/8, 382/22, 382/48
• US Class Current: 345/156
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06K 7/143 Glyph-codes
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration

Abstract

An interactive desktop system comprising a work surface, a display device such as a projector for displaying images in a first area on the work surface, a camera for capturing images in a second area on the work surface, and an image processor, coupled to the display device and to the camera, said image processor being suitably programmed (a) for causing the display of barcodes on the work surface, (b) for causing the capture of said barcodes and, in dependence on the captured information, (c) for determining the position of said second area relative to said first area. The barcodes are displayed in a horizontal then vertical orientation, with an image capture in each display orientation being performed by the camera. This enables the camera'"'"'s field of view within the displayed image to be determined. In an alternative embodiment, glyph codes may be used instead of barcodes.

Claims

1. An interactive desktop system comprising:

a work surface;

means for displaying images in a first area on the work surface;

means for capturing images in a second area on the work surface; and

calibration means, coupled to the displaying and capturing means, said calibration means for calibrating said second area with said first area, said calibration means comprising;

means for causing the display of coded information on the work surface;

means for causing the capture of said coded information; and

means for determining the position of said second area relative to said first area based on said captured coded information.

2. The system according to claim 1 wherein the second area overlaps with the first area.

3. The system according to claim 1 wherein the second area lies entirely within the first area.

4. The system according to claim 1 wherein the means for causing the display of coded information comprises means for causing the display of the coded information in a first orientation, and then in a second orientation.

5. The system according to claim 4 wherein the means for causing the capture of said coded information comprises means for causing capture of said coded information after said information is displayed in said first orientation and after said information is displayed in said second orientation.

6. The system according to claim 4 wherein in the first orientation, the coded information is displayed extending horizontally, and in the second orientation the coded information is displayed extending vertically.

7. The system according to claim 6 wherein the means for causing the capture of said coded information comprises means for causing capture of said coded information after said information is displayed in said first orientation and after said information is displayed in said second orientation.

8. The system according to claim 7 wherein the coded information comprises glyph codes.

9. The system according to claim 7 wherein the coded information comprises a barcode.

10. The system according to claim 9 wherein the barcode comprises a series of bars, arranged in a plurality of groups.

11. The system according to claim 10 wherein the displaying means comprises a projector and the capturing means comprises a camera.

12. For an interactive desktop system comprising a displaying means and a capturing means, a method for calibrating said interactive desktop system to find a field of view for said capturing means comprising the steps of:

a) displaying an all white frame using said displaying means;

b) capturing said all white frame using said capturing means;

c) displaying first coded information on a first calibration frame using said displaying means, said first coded information having a vertical orientation;

d) capturing said first coded information in said first calibration frame using said capturing means;

e) displaying second coded information on a second calibration frame using said displaying means, said second coded information having a horizontal orientation;

f) capturing said second coded information in said second calibration frame using said capturing means;

g) determining said field of view by performing the substeps of;

g1) finding horizontal edges of said first coded information using said captured all white frame and said captured first calibration frame;

g2) finding vertical edges of said second coded information using said captured all white frame and said captured second calibration frame;

g3) finding corners of said field of view for said capturing means based on said horizontal edges and said vertical edges.

13. The method as recited in claim 12 wherein said first coded information and said second coded information are bar codes.

14. The method as recited in claim 12 wherein the displaying means comprises a projector and the capturing means comprises a camera.