Machine-readable symbology and method and apparatus for printing and reading same

• US 6,012,638 A
• Filed: 08/19/1997
• Issued: 01/11/2000
• Est. Priority Date: 11/05/1993
• Status: Expired due to Fees

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Wiklof, Christopher A., Ackley, H. Sprague
• Primary Examiner(s): Le, Thien Minh
• Application Number:
  US08/914,324
• Time in Patent Office: 875 Days
• Field of Search: 235/462.09, 235/462.08, 235/462.06, 235/462.1, 235/462.11, 235/462.01, 235/494
• US Class Current: 235/462.01
• CPC Class Codes: G06K 1/121 by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06028 using bar codes
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence

Abstract

A new bar code symbology in an exemplary embodiment employs three bars (and spaces) within nine modules, similar to Code 93. Fifty-three data characters are defined, including several special mode characters. By employing these special mode characters, together with certain routines, three symbol characters can represent two 8-bit bytes, or one 16-bit word. As a result, the symbology can efficiently encode 8-bit bytes for use in computer processing, or encode 16-bit character sets such as Unicode. Symbology encodes extended channel interpretation (ECI) numbers, provides multiple numeric compression modes, provides a structured append using a single mode character, as well as other features. Additionally, the symbology includes error correction, with a Special Features Flag character indicating use of error correction in a symbol.

Claims

1. A set of machine-readable symbols corresponding to a set of data characters, the set of symbols comprising a plurality of adjacently positioned shapes having spaces between the shapes, groups of at least three shapes and three spaces defining one of at least fifty individual data characters, wherein a plurality of the groups of shapes and spaces form a printable symbol, and wherein a predetermined group of shapes and spaces in the set of symbols indicates that at least one error correction character is present within the printable symbol, and wherein an absence of the predetermined group of shapes and spaces in the printable symbol indicates an absence of error correction characters in the printable symbol.

2. The set of machine-readable symbols of claim 1 wherein the predetermined group of shapes and spaces indicates when positioned at a first position in the printable symbol that the error correction character is present within the printable symbol, and indicates when positioned in a second position within the printable symbol that the printable symbol corresponds to a selected one of a group of printable symbols.

3. The set of machine-readable symbols of claim 1 wherein the predetermined group of shapes and spaces is positioned at a location (L+2)/2 within the printable symbol, where L is a number of data characters to be encoded in the printable symbol.

4. The set of machine-readable symbols of claim 1, further comprising at least one check character in the printable symbol, the check character being generated based on a modulo sum algorithm, and wherein an error correction algorithm generates the at least one error correction character based on a Reed-Solomon algorithm.

5. The set of machine-readable symbols of claim 1 wherein at least a first error correction character is positioned proximate to a beginning of the printable symbol, and at least a second error correction character is positioned proximate to an end of the printable symbol.

6. The set of machine-readable symbols of claim 1, further comprising a message length character having a value indicative of a number of data characters to be encoded in the printable symbol, and wherein the message length character is positioned in the printable symbol adjacent to the predetermined group of shapes and spaces.

7. The set of machine-readable symbols of claim 1 wherein one of the groups of shapes and spaces represents a byte mode data character, wherein the byte mode character indicates that subsequent groups of shapes and spaces correspond to at least one character code having 8 bits.

8. The set of machine-readable symbols of claim 1 wherein one of the groups of shapes and spaces represents a word mode data character, wherein the word mode data character indicates that subsequent groups of shapes and spaces correspond to at least one 16-bit character code.

9. A machine-readable symbology having a plurality of symbol characters, the machine-readable symbology comprising an error correction flag symbol character that indicates that at least one error correction symbol character is present within a group of symbol characters, and wherein an absence of the error correction flag in the group of symbol characters indicates an absence of error correction characters in the group of symbol characters.

10. The machine-readable symbology of claim 9 wherein the error correction flag symbol character indicates when positioned at a first position in the group of symbol characters that the error correction symbol character is present, and indicates when positioned in a second position that the group of symbol characters corresponds to a selected one of a set of printable symbols.

11. The machine-readable symbology of claim 9 wherein the error correction flag symbol character is positioned at a location proximate to a middle of the group of symbol characters.

12. The machine-readable symbology of claim 9, further comprising at least one check symbol character in the group of symbol characters, the check character being generated based on an algorithm differing from an error correction algorithm that generates the at least one error correction symbol character.

13. The machine-readable symbology of claim 9, further comprising a message length symbol character in the group of symbol characters, wherein the message length symbol character has a value indicative of a number of data characters to be encoded in the group of symbol characters.

14. The machine-readable symbology of claim 9 wherein the error correction flag symbol character includes a plurality of adjacently positioned bars having spaces between the bars, wherein the bars have one of at least two widths.

15. The machine-readable symbology of claim 9 wherein the error correction flag symbol character includes a plurality of adjacently positioned bars having spaces between the bars, wherein the spaces have at least one of two widths.

16. The machine-readable symbology of claim 9 wherein the error correction flag symbol character includes a plurality of adjacently positioned bars having spaces between the bars, wherein the bars have one of at least two heights.

17. A machine-readable symbology having a plurality of symbol characters, wherein a group of symbol characters form a printable symbol, the machine-readable symbology comprising a Special Features Flag symbol character that indicates use of error correction when positioned at a first location within the printable symbol, and that indicates a second function when positioned at a second location within the printable symbol.

18. The machine-readable symbology of claim 17 wherein the Special Features Flag symbol character indicates when positioned at the first position that error correction symbol characters are present within the group of symbol characters, and indicates when positioned in the second position that the group of symbol characters corresponds to a selected one of a set of printable symbols.

19. The machine-readable symbology of claim 17 wherein the first location is proximate to a middle of the group of symbol characters.

20. The machine-readable symbology of claim 17 wherein the Special Features Flag symbol character positioned at the second location corresponds to a selected one of a set of printable symbols, and wherein a group of symbol characters includes a selected symbol character identifying the group of symbol characters with the set of printable symbols.

21. A method of converting data characters to machine-readable symbols, each symbol having a pattern of dark shapes and light spaces between the shapes, the method comprising:

determining a plurality of character codes corresponding to a plurality of data characters, respectively;

converting the plurality of character codes to a plurality of symbol values;

computing error correction values based at least some of the plurality of symbol values; and

printing a plurality of symbol characters, wherein the plurality of symbols correspond to the plurality of symbol values, to the error correction values, and to a Special Features Flag symbol character indicating that the plurality of symbol characters includes at least one symbol character corresponding to at least one error correction value.

22. The method of claim 21 wherein printing includes printing a plurality of symbol characters selected from a symbology having three shapes and nine modules per symbol character.

23. The method of claim 21 wherein printing includes printing the Special Features Flag symbol character at a first position in the plurality of symbol characters to indicate a first mode wherein the plurality of symbol characters includes at least one symbol character corresponding to at least one error correction value, and printing the Special Features Flag symbol character in a second position in the plurality of symbol characters to indicate a second mode.

24. The method of claim 21 wherein printing includes printing the Special Features Flag symbol character proximate to a middle of the plurality of symbol characters.

25. The method of claim 21 wherein printing includes printing a message length symbol character in the plurality of symbol characters.

26. The method of claim 21, further comprising:

selecting a first number of digits;

converting the first number of digits to a second number of symbol values, the second number being less than the first number;

printing the second number of symbol characters corresponding to the second number of symbol values; and

printing an additional symbol character, wherein the additional symbol character indicates that at least the second number of symbol characters correspond to digits.

27. The method of claim 21, further comprising:

selecting a number corresponding to preselected data interpretable by a computer;

converting the number to at least one selected symbol value;

printing at least one selected symbol character corresponding to the at least one selected symbol value; and

printing an additional symbol, wherein the additional symbol indicates that the at least one selected symbol corresponds to one of a plurality of predetermined numbers.

28. The method of claim 21, further comprising printing an additional symbol character, wherein the additional symbol character indicates that the plurality of symbol characters correspond to a selected position within a structured set of symbols.

29. The method of claim 21 wherein printing includes printing sever al symbols selected from a standard bar code symbology.

30. A method of decoding a bar code label formed on a surface, the method comprising:

imaging the bar code label to produce a signal representative of each of a plurality of symbol characters therefrom;

analyzing the signal to identify the symbol characters; and

converting each symbol character into a corresponding symbol value, wherein a predetermined one of the plurality of symbol values indicates that at least one error correction symbol character is present within the plurality of symbol characters, and wherein an absence of the predetermined one of the plurality of symbol values indicates that no error correction symbol characters are present within the plurality of symbol characters.

31. The method of claim 30 wherein converting first determines whether check characters in the plurality of symbol characters check, and if not, then employing the error correction characters.

32. The method of claim 30 wherein converting includes first determining whether the predetermined one of the plurality of symbol values is proximate to a middle of the plurality of symbol characters before determining that at least one error correction symbol character is present within the plurality of symbol characters.

33. A printer apparatus for printing machine-readable symbols comprising:

a processor that converts a plurality of character codes to a plurality of symbol values, wherein the plurality of character codes correspond to a plurality of data characters, respectively, wherein a predetermined one of the plurality of character codes indicates that at least one error correction symbol character is to be positioned within a printable symbol, and wherein an absence of the predetermined one of the plurality of character codes indicates an absence of error correction symbol characters in the printable symbol; and

a printer mechanism coupled to the processor that prints a plurality of symbol characters as the printable symbol, wherein the plurality of symbol characters correspond to the plurality of symbol values, respectively.

34. A reader apparatus for reading machine-readable symbols comprising:

an optical receiver that receives light reflected from a plurality of symbols and produces a signal representing the plurality of symbol characters; and

a processor coupled to the optical receiver that receives the signal and converts the plurality of symbol characters to a plurality of symbol values, wherein a predetermined one of the plurality of symbol values indicates that at least one error correction symbol character is located within the plurality of symbols, and wherein an absence of the predetermined one of the plurality of symbol values indicates an absence of error correction symbol characters within the plurality of symbols.

35. A set of bar code symbols corresponding to a set of data characters, the set of bar code symbols comprising a plurality of adjacently positioned bars having spaces between the bars, wherein a plurality of groups of bars and spaces form a non-stacked printable symbol, and wherein at least two groups of bars and spaces in the printable symbol are error correction characters.

36. The set of bar code symbols of claim 35, further comprising a predetermined group of bars and spaces that indicate that the at least two groups of bars and spaces are present within the printable symbol.

37. The set of bar code symbols of claim 36 wherein the predetermined group of bars and spaces is positioned at a location (L+2)/2 within the printable symbol, where L is a number of data characters to be encoded in the printable symbol.

38. The set of bar code symbols of claim 35 wherein at least a first error correction character is positioned proximate to a beginning of the printable symbol, and at least a second error correction character is positioned proximate to an end of the printable symbol.

39. The set of bar code symbols of claim 35 wherein one of the groups of bars and spaces represents a error correction level indicator character, wherein the error correction level indicator character indicates a level of error correction employed in the groups of bars and spaces in the printable symbols.

40. A set of machine-readable symbols corresponding to a set of data characters, the set of machine-readable symbols comprising a plurality of adjacently positioned shapes having spaces between the shapes, wherein a plurality of groups of shapes and spaces form a printable symbol and wherein at least first and second groups of shapes and spaces in the printable symbol are first and second error correction characters, and wherein the first and second groups of shapes and spaces are positioned nonadjacently within the printable symbol, and wherein the first and second groups are positioned at opposite ends of the printable symbol.

41. The set of machine-readable symbols of claim 40, wherein the set of machine-readable symbols includes start and stop characters positioned at opposing ends of the printable symbol, and wherein the first and second error correction characters are positioned proximate to the start and stop characters, respectively.

42. The set of machine-readable symbols of claim 40, further comprising a predetermined group of shapes and spaces that indicate that the printable symbol includes the first and second error correction characters.

43. A set of machine-readable symbols corresponding to a set of data characters, the set of machine-readable symbols comprising a plurality of adjacently-positioned shapes having spaces between the shapes, wherein a plurality of groups of shapes and spaces form a printable symbol and wherein at least first and second groups of shapes and spaces in the printable symbol are first and second error correction characters, and wherein the first and second groups of shapes and spaces are positioned in the printable symbol with at least some of the plurality of groups of shapes and spaces positioned therebetween.