METHOD OF IMAGING CODING PATTERN HAVING MERGED DATA SYMBOLS

• US 20100086171A1
• Filed: 08/11/2009
• Published: 04/08/2010
• Est. Priority Date: 10/02/2008
• Status: Abandoned Application

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Lapstun, Paul
• Application Number:
  US12/539,603
• Publication Number:
  US 20100086171A1
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 7/10772 Moved readers, e.g. pen, wand
• CPC Class Codes: G06K 7/1417 2D bar codes

Abstract

A method of decoding 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, the coding pattern comprising: a plurality of merged data symbols, each merged data symbol being represented by a plurality of data elements disposed on the surface, wherein each merged data symbol encodes a first individual data symbol from a first codeword and a second individual data symbol from a second codeword; (b) sampling a set of the merged data symbols contained in the imaged portion; and (c) decoding the sampled set of merged data symbols to obtain the first codeword encoded by a corresponding set of first individual data symbols.

Claims

1. A method of decoding 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 merged data symbols, each merged data symbol being represented by a plurality of data elements disposed on said surface, wherein each merged data symbol encodes a first individual data symbol from a first codeword and a second individual data symbol from a second codeword;

(b) sampling a set of said merged data symbols contained in said imaged portion; and

(c) decoding said sampled set of merged data symbols to obtain the first codeword encoded by a corresponding set of first individual data symbols.

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

decoding said sampled set of merged data symbols to obtain a second codeword encoded by a corresponding set of second individual data symbols.

3. The method of claim 2, further comprising the step of:

detecting at least one erroneous first individual data symbol in said first codeword; and

treating a second individual data symbol co-encoded with said erroneous first individual data symbol as an erasure.

4. The method of claim 1, wherein said first codeword is a common codeword identifying information common to an extended region of the surface.

5. The method of claim 1, wherein said common information is selected from the group consisting of:

a region identity, an encoding format, a region flag, a pattern scale identifier and a CRC.

6. The method of claim 2, wherein said second codeword is a coordinate codeword.

7. The method of claim 2, wherein each merged data symbol encodes a third individual data symbol, and said method further comprises the step of:

decoding said sampled set of merged data symbols to obtain a third codeword encoded by a corresponding set of third individual data symbols.

8. The method of claim 7, wherein said first codeword is a common codeword, said second codeword in an x-coordinate codeword, and said third codeword is a y-coordinate codeword.

9. The method of claim 1, wherein said first individual data symbols are multi-bit symbols.

10. The method of claim 1, wherein said second individual data symbols are 1-bit symbols.

11. The method of claim 1, wherein each merged data symbol is represented by said data elements using pulse position modulation (PPM).

12. The method of claim 11, wherein said data elements are macrodots, and wherein each merged data symbol is represented by m macrodots, each of said macrodots occupying a respective position from a plurality of predetermined possible positions p within said merged data symbol, the respective positions of said macrodots representing one of a plurality of possible data values, wherein m is an integer value of 1 or more, and p>

m.

13. The method of claim 1, wherein first codeword and said second codeword are encoded by different error-correcting codes.

14. The method of claim 13, wherein said different error-correcting codes are selected from the group consisting of:

Reed-Solomon codes, binary codes, simplex codes and cyclic position codes.

15. The method of claim 14, wherein said cyclic position codes use a cyclic code sequence, and wherein a w-bit subsequence of said cyclic code sequence defines said second codeword.

16. An optical reader configured for decoding a coding pattern disposed on a surface of a substrate, said coding pattern comprising:

a plurality of merged data symbols, each merged data symbol being represented by a plurality of data elements disposed on said surface, wherein each merged data symbol encodes a first individual data symbol from a first codeword and a second individual data symbol from a second codeword;

said optical reader comprising;

an image sensor for capturing an image of a portion of said coding pattern; and

a processor configured for performing the steps of;

(i) sampling a set of said merged data symbols contained in said imaged portion; and

(ii) decoding said sampled set of merged data symbols to obtain the first codeword encoded by a corresponding set of first individual data symbols.

17. The optical reader of claim 16, wherein said processor is further configured for:

decoding said set plurality of merged data symbols to obtain a second codeword encoded by a corresponding set of second individual data symbols.

18. The optical reader of claim 17, wherein said processor is further configured for:

detecting at least one erroneous first individual data symbol in said first codeword; and

treating a second individual data symbol co-encoded with said erroneous first individual data symbol as an erasure.

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

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

a plurality of merged data symbols, each merged data symbol being represented by a plurality of data elements disposed on said surface, wherein each merged data symbol encodes a first individual data symbol from a first codeword and a second individual data symbol from a second codeword;

(B) an optical reader comprising;

an image sensor for capturing an image of a portion of said coding pattern; and

a processor configured for performing the steps of;

(i) sampling a set of said merged data symbols contained in said imaged portion; and

(ii) decoding said sampled set of merged data symbols to obtain the first codeword encoded by a corresponding set of first individual data symbols;

(iii) detecting at least one erroneous first individual data symbol in said first codeword;

(iv) treating a second individual data symbol co-encoded with said erroneous first individual data symbol as an erasure; and

(v) decoding said sampled set of merged data symbols to obtain a second codeword encoded by a corresponding set of second individual data symbols including said erasure.

20. The system of claim 19, wherein said processor is further configured for:

decoding said set plurality of merged data symbols to obtain a second codeword encoded by a corresponding set of second individual data symbols.