Scaling techniques for printing bar code symbols

• US 6,726,104 B2
• Filed: 12/10/2001
• Issued: 04/27/2004
• Est. Priority Date: 12/18/2000
• Status: Expired due to Fees

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Schuessler, Anne, Schuessler, Frederick
• Primary Examiner(s): Le, Thien M.
• Assistant Examiner(s): Le, Uyen-Chau N.
• Application Number:
  US10/013,991
• Publication Number:
  US 20020113125A1
• Time in Patent Office: 869 Days
• Field of Search: 235/462.01, 235/462.02, 235/462.08, 235/462.09, 235/462.16, 235/494, 235/460, 235/462.1
• US Class Current: 235/462.09
• CPC Class Codes: G06K 1/121 by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26

Abstract

A method of producing a digital image of a machine readable optical code symbol having areas of different spectral characteristics and which is printable on differing printers having differing dot pitches. A desired nominal unit dimension is selected for each area of the optical code symbol; a resulting nominal unit dimension for each area is defined as a function of the dot pitch of a target printer; and a vector representation of the optical code symbol is provided using the resulting nominal unit dimension.

Claims

1. A method for producing a digital image of a machine readable optical code symbol having areas of different spectral characteristics and which is printable on differing printers having differing dot pitches, comprising the steps of:

selecting a desired nominal unit dimension for each area of the optical code symbol;

defining a resulting nominal unit dimension for each area as a function of the dot pitch of a target printer; and

providing a vector representation of the optical code symbol using the resulting nominal unit dimension.

2. The method according to claim 1, wherein the optical code symbol is a bar code having bars and spaces of varying widths.

3. The method according to claim 2, wherein the bar code is an n,k bar code and wherein the nominal unit dimension is a module width.

4. The method according to claim 3, wherein the n,k bar code is an 11,3 bar code wherein the bars and spaces are from 1 to 4 modules in length.

5. The method according to claim 1, wherein the code symbol is a two-dimensional code symbol.

6. The method according to claim 5, wherein the two-dimensional code symbol is an n,k bar code and wherein the nominal unit dimension is at least one of the X dimension and the Y dimension.

7. The method according to claim 6, wherein the bar code is PDF417.

8. The method according to claim 1, further comprising the steps of:

selecting a desired nominal starting position for each successive area of the optical code symbol;

defining a resulting nominal starting position for each successive area as a function of the dot pitch of a target printer; and

providing a vector representation of the optical code symbol using the resulting nominal unit dimension and the resulting nominal starting positions.

9. A method for producing a digital image of a machine readable optical code symbol having areas of different spectral characteristics and which is printable on differing printers having differing dot pitches, comprising the steps of:

selecting a desired nominal starting position for each successive area of the optical code symbol;

defining a resulting nominal starting position for each successive area as a function of the dot pitch of a target printer; and

providing a vector representation of the optical code symbol using the resulting nominal starting positions.

10. The method according to claim 9, wherein the optical code symbol is a bar code having bars and spaces of varying widths.

11. The method according to claim 10, wherein the bar code is an n,k bar code and wherein the nominal unit dimension is a module width.

12. The method according to claim 11, wherein the n,k bar code is an 11,3 bar code wherein the bars and spaces are from 1 to 4 modules in length.

13. The method according to claim 9, wherein the code symbol is a two-dimensional code symbol.

14. The method according to claim 13, wherein the two-dimensional code symbol is an n,k bar code and wherein the nominal unit dimension is at least one of the X dimension and the Y dimension.

15. The method according to claim 14, wherein the bar code is PDF417.

16. A method for representing a digital image of a machine readable optical code symbol comprising at least one graphical element selected from a set of graphical elements, the symbol having a specified unit width in a first dimension, and which is printable on differing printers having differing dot pitches, comprising the steps of:

adjusting the specified unit width to fit an exact number of printed dots on a target printer;

providing a vector representation of each graphical element in the set using multiples of the adjusted unit width; and

specifying the symbol as a series of references to the vector representations that correspond to the least one graphical element that defines the symbol.

17. The method of claim 16, wherein the step of adjusting comprises adjusting the specified unit width to a nearest smaller number of dots.

18. The method of claim 16, wherein the optical code symbol is a bar code and the graphical elements comprise bars and spaces.

19. The method of claim 18, wherein the graphical elements have respective widths along the first dimension that are integral multiples of a module width.

20. The method of claim 19, wherein the set of graphical elements comprises bars 1, 2, 3, and 4 modules wide and spaces 1, 2, 3, and 4 modules wide.

21. The method of claim 16, wherein each vector representation starting at a relative drawing point, wherein after the respective graphical element is drawn, the relative drawing point is repositioned on a unit width boundary.

22. The method of claim 21, wherein the vector representation shifts at least one edge of the graphical element by a specified number of dots in the first dimension in accordance with an ink-spread compensation parameter.

23. The method of claim 16, wherein the step of adjusting comprises the step of:

determining a printer dot pitch in the first dimension;

dividing the specified unit width by the dot pitch to determine a number of printed dots needed to fill the unit width;

truncating the number of printed dots to an integral number of dots; and

multiplying the truncated number by the dot pitch to determine the adjusted unit width.

24. The method of claim 16, further comprising the step of restricting the adjusted unit width to within at least one of a minimum and maximum unit width.

25. The method of claim 16, further comprising the steps of:

detecting if a scale of the image has been changed from a default scale; and

overriding the changed scale if a scale-lock setting is on.

26. The method of claim 25, further comprising the step of permitting scaling of the image within predefined limits if the scale-lock setting is off.

27. A computer image file representing an image of a machine readable optical code symbol comprising at least one graphical element selected from a set of graphical elements, the symbol having a specified unit width in a first dimension and being printable on differing printers having differing dot pitches, the image file comprising instructions which can be processed by a raster image processor to generate a rasterized version of the symbol, the instructions comprising:

a first portion comprising instructions to adjust the specified unit width to fit an exact number of printed dots on a target printer;

a second portion comprising vector representations of each graphical element in the set using multiples of the adjusted unit width; and

a third portion comprising a series of references to the vector representations, the references corresponding to the graphical elements that define the symbol.

28. The image file of claim 27, wherein the first portion contains instructions to adjust the specified unit width to a nearest smaller number of dots.

29. The image file of claim 27, wherein the optical code symbol is a bar code and the graphical elements comprise bars and spaces.

30. The image file of claim 29, wherein the graphical elements have respective widths along the first dimension that are integral multiples of a module width.

31. The image file of claim 30, wherein the second portion defines vector representations of bars 1, 2, 3, and 4 modules wide and spaces 1, 2, 3, and 4 modules wide.

32. The image file of claim 27, wherein each vector representation starts at a relative drawing point and, wherein after the respective graphical element is drawn, the relative drawing point is repositioned on a unit width boundary.

33. The image file of claim 32, wherein each vector representation is configured to shift at least one edge of the graphical element by a specified number of dots in the first dimension in accordance with an ink-spread compensation parameter.

34. The image file of claim 27, wherein the a first portion contains instructions to:

determine a printer dot pitch in the first dimension;

divide the specified unit width by the dot pitch to determine a number of printed dots needed to fill the unit width;

truncate the number of printed dots to an integral number of dots; and

multiply the truncated number by the dot pitch to determine the adjusted unit width.

35. The image file of claim 27, wherein the first portion further contains instructions to restrict the adjusted unit width to within at least one of a minimum and maximum unit width.

36. The image file of claim 27, the instructions further comprising:

a fourth portion containing instructions to detect if a scale of the image has been changed from a default scale and override the changed scale if a scale-lock setting is on.

37. The image file of claim 36, wherein the fourth portion further comprises instructions to permit scaling of the image within predefined limits if the scale-lock setting is off.

38. The image file of claim 27, wherein the instructions are in PostScript format.

39. An electronic document having the image file of claim 27 embedded therein.

40. The image file of claim 27, further comprising at least one of:

a parameter specifying an amount of unprinted border area to leave adjacent to the symbol when printed;

a parameter indicating whether the image file can be rescaled after being embedded in an electronic document;

a parameter indicating an amount of print gain adjustment to be applied to compensate for ink spread;

a parameter indicating whether to print human-readable text corresponding to data encoded by the symbol; and

a parameter indicating a height at which the graphical elements should be printed.