GLOBAL METADATA EMBEDDING AND DECODING

• US 20090119573A1
• Filed: 07/25/2008
• Published: 05/07/2009
• Est. Priority Date: 04/22/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Li, Yue, Wang, Qiang, Dang, Yingnong, Wu, Jiang, Wang, Jian, Lin, Zhouchen, Zhang, Chunhui
• Granted Patent: US 8,156,153 B2
• Time in Patent Office: Days
• US Class Current: 715/209
• 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: G06F 40/171 by use of digital ink

Abstract

In accordance with embodiments of the invention, global metadata, such as a document identifier, which may be a globally unique identifier, is embedded into an embedded interactive code document by combining a first m-array and a plurality of copies of the first m-array to generate a combined m-array with encoded global metadata such that respective start positions (x_d,y_d)ⁱ of the plurality of copies of the first m-array in the combined m-array are each shifted, by respective amounts that are based on respective portions of the global metadata, relative to a start position of the first m-array in the combined m-array. Global metadata may be decoded from the combined m-array by determining the respective amounts by which the plurality of copies of the first m-array are shifted, relative to the first m-array, in the combined m-array and by combining the respective amounts to produce a decoded value of the global metadata.

Claims

1. A system that embeds global metadata into an embedded interactive code document, the system comprising:

a first m-array that contains a first repeating sequence of bits;

global metadata that specifies a document-identification information for the embedded interactive code document;

a plurality of copies of the first m-array; and

a global-meta-data-encoding module that combines the first m-array and the plurality of copies of the first m-array to generate a combined m-array with encoded global metadata such that respective start positions (x_d,y_d)ⁱ of the plurality of copies of the first m-array in the combined m-array are each shifted, by respective amounts that are based on respective portions of the global metadata, relative to a start position of the first m-array in the combined m-array.

2. The system of claim 1, wherein the first m-array is a position m-array.

3. The system of claim 2, wherein the plurality of copies of the first m-array are global-metadata m-arrays.

4. The system of claim 1, wherein the respective start positions (x_d,y_d)ⁱ of the plurality of copies of the first m-array in the combined m-array are calculated as

$x_d^i=\mathrm{mod}(\mathrm{global}$



metadata 



portion i , 2 n 2 + 1 ) , 

y d = int 

( global 



metadata 



portion i 2 n 2 + 1 ) ,

where n is an order of the first m-array and 0≦

global metadata portion_i ≦

2ⁿ−

2.

5. The system of claim 4, wherein the global metadata is a globally unique identifier.

6. A system that decodes global metadata from an embedded interactive code document, the system comprising:

a combined m-array with encoded global metadata, wherein global metadata is encoded in the combined m-array via respective start positions (x_d,y_d)ⁱ of a plurality of copies of a first m-array in the combined m-array being shifted, by an amount that is based on respective portions of the global metadata, relative to a start position of the first m-array in the combined m-array with encoded global metadata;

a global-meta-data-decoding module that decodes the global metadata from the combined m-array by determining the respective amounts by which the plurality of copies of the first m-array are shifted, relative to the first m-array, in the combined m-array and by combining the respective amounts to produce a decoded value of the global metadata.

7. The system of claim 6, wherein the first m-array is a position m-array and the plurality of copies of the first m-array are global-metadata m-arrays.

8. The system of claim 6, wherein the global-meta-data-decoding module decodes, from the combined m-array, the first m-array and each of the plurality of copies of the first m-array separately from one another.

9. The system of claim 8, wherein the global-meta-data-decoding module determines a first position (x_p,y_p) of the point P in the first m-array and respective shifted positions (x_m,y_m)ⁱ of the point P in the plurality of copies of the first m-array.

10. The system of claim 9, wherein the global-meta-data-decoding module calculates respective values for the portions of global metadata as

$\mathrm{global}$



metadata 



portion i = mod 

( y p - y m i , 2 n 2 - 1 ) ·

( 2 n 2 + 1 ) + mod ( x p - x m i , 2 n 2 + 1 ) ,

where n is an order of the first m-array.

11. The system of claim 10, wherein, for a plurality of images of the embedded interaction code document, respective values of global metadata portion_i that occur most often are selected for use as respective global metadata portion values for calculating the decoded value of the global metadata.

12. The system of claim 11, wherein the decoded value of the global metadata is calculated as

$\mathrm{decoded}$



global 



metadata = ∑

i = 0 j 

selected 



global 



metadata 



portion i ·

( 2 n - 1 ) i ,

where j is a number of dimensions in which the global metadata was encoded and n is an order of the first m-array.

13. A computer-readable medium containing computer-executable instructions for embedding global metadata into an embedded interactive code document by combining a first m-array and a plurality of copies of the first m-array to generate a combined m-array with encoded global metadata such that respective start positions (x_d,y_d)ⁱ of the plurality of copies of the first m-array in the combined m-array are each shifted, by respective amounts that are based on respective portions of the global metadata, relative to a start position of the first m-array in the combined m-array.

14. The computer-readable medium of claim 13, having further computer-executable instructions for calculating the respective start positions (x_d,y_d)ⁱ of the plurality of copies of the first m-array in the combined m-array as

$x_d^i=\mathrm{mod}(\mathrm{global}$



metadata 



portion i , 2 n 2 + 1 ) , 

y d = int ( global 



metadata 



portion i 2 n 2 + 1 ) ,

where n is an order of the first m-array and 0≦

global metadata portion_i ≦

2ⁿ−

2.

15. The computer-readable medium of claim 14, having further computer-executable instructions for decoding the global metadata from the combined m-array by determining the respective amounts by which the plurality of copies of the first m-array are shifted, relative to the first m-array, in the combined m-array and by combining the respective amounts to produce a decoded value of the global metadata.

16. The computer-readable medium of claim 15, having further computer-executable instructions for decoding, from the combined m-array, the first m-array and each of the plurality of copies of the first m-array separately from one another.

17. The computer-readable medium of claim 16, having further computer-executable instructions for determining a first position (x_p,y_p) of the point P in the first m-array and respective shifted positions (x_m,y_m)ⁱ of the point P in the plurality of copies of the first m-array.

18. The computer-readable medium of claim 17, having further computer-executable instructions for calculating respective values for the portions of global metadata as

$\mathrm{global}$



metadata 



portion i = mod 

( y p - y m i , 2 n 2 - 1 ) ·

( 2 n 2 + 1 ) + mod ( x p - x m i , 2 n 2 

+ 1 ) ,

where n is an order of the first m-array.

19. The computer-readable medium of claim 18, having further computer-executable instructions for selecting, for a plurality of images of the embedded interaction code document, respective values, which occur most often, of global metadata portion_i for use as respective global metadata portion values for calculating the decoded value of the global metadata.

20. The computer-readable medium of claim 19, having further computer-executable instructions for calculating the decoded value of the global metadata as

$\mathrm{decoded}$



global 



metadata = ∑

i = 0 j 

selected 



global 



metadata 



portion i ·

( 2 n - 1 ) i ,

where j is a number of dimensions in which the global metadata was encoded and n is an order of the first m-array.