Method and system for creating and using barcodes
Methods for efficiently retrieving information from an image of a symbol are described. Symbols are described that contain detection patterns that facilitate the determination of location, alignment, size and orientation of the symbol in an image. Detection patterns are described that possess geometric shapes susceptible to efficient decoding using probabilistic detection algorithms. Detection patterns are described that are provided in colors, shapes and sizes different from the color, shape and sizes of modules carrying information in the symbol. Methods are described for identifying the location and size of detection patterns in images of the symbol and for locating modules in the symbol to facilitate extraction of information carried by the modules.
1. A method, comprising:
generating a two-dimensional (2D) barcode comprising a plurality of square modules that collectively encode data;
substantially centering or centering at least one circular finder pattern at a reference point within the 2D barcode; and
locating at least one circular alignment pattern within the 2D barcode according to a geometric relationship with the at least one circular finder pattern.
2. The method of claim 1 , further comprising locating at least one position detection pattern within the 2D barcode.
3. The method of claim 2 , wherein the generating includes forming the at least one position detection pattern to be distinguishable from the plurality of square modules by color.
4. The method of claim 2 , wherein the locating the at least one position detection pattern comprises locating a circular position detection pattern.
5. The method of claim 1 , wherein the generating includes forming the at least one circular alignment pattern including determining a size of the at least one circular alignment pattern as a function of a size of the at least one circular finder pattern.
6. The method of claim 1 , further comprising locating at least one orientation pattern within the 2D barcode.
7. The method of claim 6 , wherein the generating includes forming the at least one orientation pattern to be distinguishable from the plurality of square modules by color.
8. The method of claim 6 , wherein the locating the at least one orientation pattern comprises locating a circular orientation pattern.
9. The method of claim 1 , wherein the generating includes forming the at least one circular finder pattern to be distinguishable by a color from the plurality of square modules.
10. The method of claim 1 , wherein the locating includes locating the at least one circular alignment pattern at a location within the 2D barcode determined as a function of a radius of the at least one circular finder pattern.
11. The method of claim 1 , wherein the locating comprises locating the at least one circular alignment pattern based on a center of at least one module of the plurality of square modules lying along a line connecting a center of the at least one circular finder pattern and a center of the at least one circular alignment pattern.
12. The method of claim 11 , further comprising locating the center of the at least one module along the line at a distance from the center of the at least one circular finder pattern that is a defined fraction of a distance between the center of the at least one circular finder pattern and the center of the at least circular alignment pattern.
13. A system, comprising:
a barcode generator configured to:
arrange a plurality of square modules into a two-dimensional (2D) barcode to encode data;
locate at least one circular finder pattern at a reference point within the 2D barcode; and
locate at least one circular alignment pattern within the 2D barcode based on a defined geometric relationship with the at least one circular finder pattern.
14. The system of claim 13 , wherein the barcode generator is further configured to locate at least one position detection pattern within the 2D barcode.
15. The system of claim 14 , wherein the barcode generator is further configured to generate the at least one position detection pattern to have a different color than the plurality of square modules.
16. The system of claim 14 , wherein the barcode generator is further configured to form the at least one position detection pattern to be circular.
17. The system of claim 13 , wherein the barcode generator is further configured to determine a size for the at least one circular alignment pattern as a function of a size of the at least one circular finder pattern.
18. The system of claim 13 , wherein the barcode generator is further configured to locate at least one orientation pattern within the 2D barcode.
19. The system of claim 18 , wherein the barcode generator is further configured to generate the at least one circular orientation pattern to have a different color than the plurality of square modules.
20. The system of claim 18 , wherein the barcode generator is further configured to form the at least one orientation pattern to be circular.
21. The system of claim 13 , wherein the barcode generator is further configured to generate the at least one circular finder pattern to have a different color than the plurality of square modules.
22. The system of claim 13 , wherein the barcode generator is further configured to determine a location for the at least one circular alignment pattern as a function of a radius of the at least one circular finder pattern.
23. The system of claim 13 , wherein a center of at least one module of the plurality of square modules is located on a line connecting a center of the at least one circular finder pattern and a center of the at least one circular alignment pattern.
24. The system of claim 23 , wherein the center of the at least one module is located on the line at a distance from the center of the at least one circular finder pattern that is a defined fraction of a distance between the center of the at least one circular finder pattern and the center of the at least one circular alignment pattern.
25. The computer-readable medium of claim 23 , the operations further including locating the center of the at least one module along the line at a distance from the center of the at least one circular finder pattern that is a defined fraction of a distance between the center of the at least one circular finder pattern and the center of the at least one circular alignment pattern.
26. A computer-readable storage medium having stored thereon computer-executable components that, in response to execution, cause a computing system including a processor to perform operations, including:
creating a two-dimensional (2D) barcode comprising a plurality of square modules that collectively encode data;
substantially centering or centering at least one circular finder pattern at a reference point within the 2D barcode; and
locating at least one circular alignment pattern within the 2D barcode according to a geometric relationship with the at least one circular finder pattern.
27. The computer-readable medium of claim 26 , the operations further including locating at least one position detection pattern within the 2D barcode.
28. The computer-readable medium of claim 27 , the operations further including forming the at least one position detection pattern to be distinguishable from the plurality of square modules by color.
29. The computer-readable medium of claim 27 , the operations further including forming the at least one position detection pattern to be circular.
30. The computer-readable medium of claim 26 , the operations further including sizing the at least one circular alignment pattern as a function of a size of the at least one circular finder pattern.
31. The computer-readable medium of claim 26 , the operations further including locating at least one orientation pattern within the 2D barcode.
32. The computer-readable medium of claim 31 , the operations further including forming the at least one orientation pattern to be distinguishable from the plurality of square modules by color.
33. The computer-readable medium of claim 31 , the operations further including forming the at least one orientation pattern to be circular.
34. The computer-readable medium of claim 26 , the operations further including forming the at least one circular finder pattern to be distinguishable by color from the plurality of square modules.
35. The computer-readable medium of claim 26 , the operations further including selecting a location for the at least one circular alignment pattern as a function of a radius of the at least one circular finder pattern.
36. The computer-readable medium of claim 26 , the operations further including locating the at least one circular alignment pattern including determining a center of at least one module of the plurality of square modules lying along a line connecting a center of the at least one circular finder pattern and a center of the at least one circular alignment pattern.
37. An apparatus, comprising:
means for generating a two-dimensional (2D) barcode comprising a plurality of square modules that collectively encode data;
means for locating at least one circular finder pattern within the 2D barcode; and
means for locating at least one circular alignment pattern within the 2D barcode based on a geometric relationship with the at least one circular finder pattern.