Method of estimating position of writing nib relative to an optical sensor

• US 7,649,523 B2
• Filed: 07/19/2006
• Issued: 01/19/2010
• Est. Priority Date: 02/24/2000
• Status: Expired due to Fees

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, Lapstun, Paul, King, Tobin Allen
• Primary Examiner(s): Shalwala; Bipin
• Assistant Examiner(s): KOVALICK, VINCENT E
• Application Number:
  US11/488,832
• Publication Number:
  US 20060284859A1
• Time in Patent Office: 1,280 Days
• Field of Search: 345/166, 345/173, 345/178, 345/179, 178/18.01, 178/18.03, 178/18.09, 382/181
• US Class Current: 345/166
• CPC Class Codes: B41J 13/106 for the sheet output section
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B42C 19/02 starting with single sheets
• CPC Class Codes: B42C 9/0006 by applying adhesive to a stack of sheets
• CPC Class Codes: B42C 9/0081 applying adhesive to individual sheets for binding them together by fusing, welding B42C9/0093
• CPC Class Codes: B42P 2261/04 Producing books by printing sheets in following order, e.g. for ordering via the Internet
• CPC Class Codes: B65H 29/34 from supports slid from under the articles
• CPC Class Codes: B65H 37/04 for securing together articles or webs, e.g. by adhesive, stitching or stapling adhering replacement to expiring web during change of web roll B65H19/18
• 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: G06F 40/169 Annotation, e.g. comment data or footnotes
• CPC Class Codes: G06Q 10/10 Office automation; Time management
• CPC Class Codes: G06Q 20/085 involving remote charge determination or related payment systems
• CPC Class Codes: G06Q 20/10 specially adapted for electronic funds transfer [EFT] systems; specially adapted for home banking systems
• CPC Class Codes: G06Q 20/40 Authorisation, e.g. identification of payer or payee, verification of customer or shop credentials; Review and approval of payers, e.g. check credit lines or negative lists
• CPC Class Codes: G06Q 30/0241 Advertisements
• CPC Class Codes: G06Q 40/00 Finance; Insurance; Tax strategies; Processing of corporate or income taxes
• CPC Class Codes: G06V 10/19 by sensing codes defining pattern positions
• CPC Class Codes: G06V 10/225 based on a marking or identifier characterising the area
• CPC Class Codes: G06V 30/1423 the instrument generating sequences of position coordinates corresponding to handwriting preprocessing or recognising digital ink G06V30/32
• CPC Class Codes: H04L 65/4015 where at least one of the additional parallel sessions is real time or time sensitive, e.g. white board sharing, collaboration or spawning of a subconference
• CPC Class Codes: H04L 67/131 : Protocols for games, networked simulations or virtual reality
• CPC Class Codes: H04L 67/52 : specially adapted for the location of the user terminal
• CPC Class Codes: H04W 4/02 : Services making use of location information

Abstract

A method of estimating a position of a point on a writing implement relative to an optical sensor mounted on the writing implement is provided. The method comprises the steps of: (a) placing the point in contact with a coded surface; (b) capturing, using the sensor, at least two images of the coded surface at different rotations of the writing implement relative to the surface; (c) determining, from a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image; and (d) estimating, from the estimated rotations and viewing distances, the position of the point relative to the optical sensor.

Claims

1. A method of estimating a position of a point on a writing implement relative to an optical sensor mounted on the writing implement, said method comprising the steps of:

placing the point in contact with a coded surface;

capturing, using the sensor, at least two images of the coded surface at different rotations of the writing implement relative to the surface;

determining, from a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image; and

estimating, from the estimated rotations and viewing distances, the position of the point relative to the optical sensor.

2. The method of claim 1, comprising the steps of:

generating a line for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least two lines generated; and

estimating, from at least one point of intersection of the lines, the position of the point relative to the sensor.

3. The method of claim 1, wherein the coded surface comprises coded data identifying the surface and/or a plurality of locations on the surface.

4. The method of claim 3, wherein the coded data is defined by a plurality of printed tags, each tag containing coded data identifying the surface and its own location on the surface.

5. The method of claim 1, wherein each rotation is defined by at least one of a pitch, roll or yaw component.

6. A writing implement comprising:

a body;

a point at one end of the body for contacting a coded surface;

an optical sensor mounted on the body for capturing images of the coded surface; and

a processor configured for;

determining, from a perspective distortion of the coded surface in at least two images captured at different rotations, an estimated rotation and viewing distance for each image; and

estimating, from the estimated rotations and viewing distances, the position of the point relative to the optical sensor.

7. The writing implement of claim 6, wherein the processor is configured for:

generating a line for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least two lines generated; and

estimating, from at least one point of intersection, the position of the point relative to the sensor.

8. The writing implement of claim 7, wherein the optical sensor is detachably mounted on the body.

9. A method of estimating a position of a point on a writing implement relative to an optical sensor mounted on the writing implement and a curvature of the writing implement at the point, the method comprising the steps of:

placing the point in contact with a coded surface;

capturing, using the sensor, at least three images of the coded surface at different rotations of the writing implement relative to the surface;

determining, from a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image; and

estimating, from the estimated rotations and viewing distances, the position of the point relative to the optical sensor and the curvature of the writing implement at the point.

10. The method of claim 9, comprising the steps of:

generating a line for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least three lines generated; and

estimating, from at least two points of intersection, the position of the point relative to the sensor and the curvature of the writing implement at the point.

11. The method of claim 10, wherein the coded surface comprises coded data identifying the surface and/or a plurality of locations on the surface.

12. The method of claim 11, wherein the coded data is defined by a plurality of printed tags, each tag containing coded data identifying the surface and its own location on the surface.

13. The method of claim 9, wherein each rotation is defined by at least one of a pitch, roll or yaw component.

14. A writing implement comprising:

a body;

a point at one end of the body for contacting a coded surface;

an optical sensor mounted on the body for capturing images of the coded surface; and

a processor configured for;

determining, from a perspective distortion of the coded surface in at least three images captured at different rotations, an estimated rotation and viewing distance for each image; and

estimating, from the estimated rotations and viewing distances, the position of the point relative to the optical sensor and the curvature of the writing implement at the point.

15. The writing implement of claim 14, wherein the processor is configured for:

generating a line for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least three lines generated; and

estimating, from at least two points of intersection, the position of the point relative to the sensor and the curvature of the writing implement at the point.

16. The writing implement of claim 14, wherein the optical sensor is detachably mounted on the body.

17. A method of estimating a convex shape of at least part of an object, said method comprising the steps of:

attaching an optical sensor to the object;

placing the object in contact with a coded surface;

capturing, using the sensor, at least three images of the coded surface at different rotations of the object relative to the surface;

determining, from a perspective distortion of the coded surface in each image, an estimated rotation and viewing distance for each image; and

estimating, from the estimated rotations and viewing distances, the convex shape of at least part of the object.

18. The method of claim 17, comprising the steps of:

generating a line for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least three lines generated; and

estimating, from at least two points of intersection, the convex shape of at least part of the object.

19. The method of claim 17, comprising the steps of:

generating a halfspace for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least three halfspaces generated; and

estimating, from the intersection of the halfspaces, the convex shape of at least part of the object.

20. The method of claim 17, wherein the coded surface comprises coded data identifying the surface and/or a plurality of locations on the surface.

21. The method of claim 20, wherein the coded data is defined by a plurality of printed tags, each tag containing coded data identifying the surface and its own location on the surface.

22. The method of claim 17, wherein each rotation is defined by at least one of a pitch, roll or yaw component.

23. A device for estimating a convex shape of at least part of an object, said device comprising:

means for attaching the device to the object;

an optical sensor for capturing images of a coded surface in contact with the object; and

a processor configured for;

determining, from a perspective distortion of the coded surface in at least three images captured at different rotations, an estimated rotation and viewing distance for each image; and

estimating, from the estimated rotations and viewing distances, the convex shape of at least part of the object.

24. The device of claim 23, wherein the processor is configured for:

generating a line for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least three lines generated; and

estimating, from at least two points of intersection, the convex shape of at least part of the object.

25. The device of claim 23, wherein the processor is configured for:

generating a halfspace for each rotation using a corresponding estimated rotation and viewing distance;

intersecting the at least three halfspaces generated; and

estimating, from the intersection of the halfspaces, the convex shape of at least part of the object.