Method of imaging a coding pattern having fragments of common data distributed in each tag

• US 7,905,405 B2
• Filed: 02/05/2008
• Issued: 03/15/2011
• Est. Priority Date: 02/08/2007
• Status: Expired due to Fees

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, Lapstun, Paul
• Primary Examiner(s): Frech; Karl D.
• Application Number:
  US12/025,760
• Publication Number:
  US 20080191019A1
• Time in Patent Office: 1,134 Days
• Field of Search: 235/454, 235/487, 235/462.08, 235/462.09, 235/462.1
• US Class Current: 235/454
• 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 fragments of common data contained in the imaged portion; and (c) assembling the decoded fragments to determine the common data. The imaged portion has a diameter of at least one tag diameter and less than two tag diameters.

Claims

1. A method of imaging a coding pattern disposed on a surface of a substrate, said method comprising the steps of:

(a) operatively positioning an optical reader relative to said surface and capturing an image of a portion of said coding pattern, said coding pattern comprising;

a plurality of target elements defining a target grid, said target grid comprising a plurality of cells, wherein neighboring cells share target elements;

a plurality of data elements contained in each cell; and

a plurality of tags, each tag being defined by a plurality of contiguous cells, each tag comprising respective local tag data encoded by a respective set of said data elements, each tag comprising common data encoded by a respective set of said data elements, said common data being defined as data common to a plurality of contiguous tags, wherein each cell comprises a fragment of said common data;

(b) sampling and decoding each fragment of common data contained in said imaged portion; and

(c) assembling said decoded fragments to determine said common data, wherein said portion has a diameter of at least one tag diameter and less than two tag diameters.

2. The method of claim 1, wherein said common data is region identity data uniquely identifying a region of said surface.

3. The method of claim 1, wherein said common data uniquely identifies said substrate.

4. The method of claim 1, wherein said data elements are macrodots.

5. The method 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 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.

7. The method of claim 1, 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 method 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 method of claim 7, wherein said common data is encoded as one or more common codewords, each common codeword being comprised of a set of said Reed-Solomon symbols.

10. The method of claim 7, wherein each symbol group comprises a fragment of at least one of said one or more common codewords, and contiguous symbol groups are arranged such that any tag-sized portion of said coding pattern is guaranteed to contain said one or more common codewords irrespective of whether a whole tag is contained in said portion.

11. The method of claim 1, further comprising the step of:

sampling and decoding said local tag data.

12. 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 target elements defining a target grid, said target grid comprising a plurality of cells, wherein neighboring cells share target elements;

a plurality of data elements contained in each cell; and

a plurality of tags, each tag being defined by a plurality of contiguous cells, each tag comprising respective local tag data encoded by a respective set of said data elements, each tag comprising common data encoded by a respective set of said data elements, said common data being defined as data common to a plurality of contiguous tags,

(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 each fragment of common data visible in said field-of-view; and

(ii) assembling said decoded fragments to determine said common data.

13. The system of claim 12, wherein said common data is region identity data uniquely identifying a region of said surface.

14. The system of claim 12, wherein said common data uniquely identifies said substrate.

15. The system of claim 12, wherein said data elements are macrodots.

16. The system of claim 12, 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.

17. The system of claim 16, 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.

18. The system of claim 16, wherein said common data is encoded as one or more common codewords, each common codeword being comprised of a set of said Reed-Solomon symbols.

19. The system of claim 18, wherein each symbol group comprises a fragment of at least one of said one or more common codewords, and contiguous symbol groups are arranged such that any tag-sized portion of said coding pattern is guaranteed to contain said one or more common codewords irrespective of whether a whole tag is contained in said portion.

20. The system of claim 12, wherein said reader is an optically imaging pen having a nib.