Method of imaging coding pattern comprising tags with divided x and y coordinate data

• US 8,107,732 B2
• Filed: 02/05/2008
• Issued: 01/31/2012
• Est. Priority Date: 02/08/2007
• Status: Expired due to Fees

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Lapstun, Paul, Silverbrook, Kia
• Primary Examiner(s): Desire, Gregory M
• Application Number:
  US12/025,764
• Publication Number:
  US 20080193045A1
• Time in Patent Office: 1,456 Days
• Field of Search: 382/181, 382/321, 235/375, 235/462.09, 235/462.01
• US Class Current: 382/188
• CPC Class Codes: G06F 2203/0337 Status LEDs integrated in the mouse to provide visual feedback to the user about the status of the input device, the PC, or the user
• CPC Class Codes: G06F 2203/0384 Wireless input, i.e. hardware and software details of wireless interface arrangements for pointing devices
• CPC Class Codes: G06F 3/0321 by optically sensing the absolute position with respect to a regularly patterned surface forming a passive digitiser, e.g. pen optically detecting position indicative tags printed on a paper sheet constructional details of pen-shaped pointing devices G06F3/03545, G06F3/03542, G06F3/037
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06K 19/06 characterised by the kind of the digital marking, e.g. shape, nature, code
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06T 7/32 using correlation-based methods

Abstract

A method of imaging a coding pattern disposed on a surface of a substrate. The method comprises the steps of: (a) operatively positioning an optical reader relative to the surface and capturing an image of a portion of the coding pattern; (b) sampling and decoding x-coordinate data and y-coordinate data contained in the imaged portion; and (c) determining a position of the pen. The imaged portion has a diameter of at least one tag diameter and less than two tag diameters. The x-coordinate data and y-coordinate are each replicated in the tag.

Claims

1. A system for imaging a coding pattern disposed on a surface of a substrate, said system comprising:

(A) said substrate, wherein said coding pattern comprises;

a plurality of contiguous tags, each tag comprising x-coordinate data and y-coordinate data, wherein a y-axis is nominally defined as north-south and an x-axis is nominally defined as east-west; and

a plurality of data elements contained in each tag, said x-coordinate data being represented by a respective set of data elements and said y-coordinate data being represented by a respective set of data elements, wherein;

said x-coordinate data has two replications within a respective tag, a first replication in a western half of said tag and a second replication in an eastern half of said tag; and

said y-coordinate data has two replications within a respective tag, a first replication in a northern half of said tag and a second replication in a southern half of said tag; and

(B) an optical reader comprising;

an image sensor for capturing an image of a portion of said coding pattern, said image sensor having a field-of-view of at least one tag diameter and less than two tag diameters; and

a processor configured for performing the steps of;

(i) sampling and decoding x-coordinate data and y-coordinate data within said captured image; and

(ii) determining a position of said pen.

2. The system of claim 1, wherein each tag is square.

3. The system of claim 1, wherein said coding pattern comprises:

a plurality of target elements defining a target grid, said target grid comprising a plurality of cells, wherein neighboring cells share target elements and wherein each tag is defined by a plurality of contiguous cells.

4. The system of claim 3, wherein each tag is square and comprises M² contiguous square cells, wherein M is an integer having a value of at least 2.

5. The system of claim 4, wherein a portion of data is represented by a macrodot occupying one of a plurality of possible positions within a cell, each position representing one of a plurality of possible data values.

6. The system of claim 5, wherein a n-bit portion of data is represented by a macrodot occupying one of 2ⁿ possible positions within a cell, each position representing one of 2ⁿ possible data values, wherein n is an integer.

7. The system of claim 3, wherein each cell defines a symbol group, each symbol group comprising a plurality of Reed-Solomon symbols encoded by a plurality of said data elements.

8. The system of claim 7, wherein each symbol comprises two halves, each half comprising 2 bits of data represented by a macrodot occupying one of 4 possible positions within said half.

9. The system of claim 1, wherein said x-coordinate data is encoded as an x-coordinate codeword comprised of a respective set of Reed-Solomon symbols, and said y-coordinate data is encoded as a y-coordinate codeword comprised of a respective set of Reed-Solomon symbols.

10. The system of claim 1, wherein said reader is an optically imaging pen having a nib.