Embedded interaction code recognition

• US 20060242622A1
• Filed: 04/22/2005
• Published: 10/26/2006
• Est. Priority Date: 04/22/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Wang, Qiang, Dang, Yingnong, Wu, Jiang, Wang, Jian, Chen, Liyong
• Granted Patent: US 7,599,560 B2
• Time in Patent Office: Days
• US Class Current: 717/106
• 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: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1456 determining the orientation of the optical code with respect to the reader and correcting therefore

Abstract

In accordance with embodiments of the invention, embedded interaction code (EIC) symbols are recognized. EIC dots are generated based on effective EIC symbols, which have been generated by processing an image containing the EIC symbols, by obtaining graylevels of selected positions of the EIC-symbols. Rotated EIC dots are generated based on the EIC dots by determining which grid cells correspond to the EIC symbols and by determining which direction is a correct orientation of the EIC symbols. A homography matrix is updated with orientation information based on the EIC dots. EIC bits are extracted from the rotated EIC dots based on graylevels of selected positions of the rotated EIC dots.

Claims

1. A system that recognizes embedded interaction code (EIC) symbols, the system comprising:

an EIC-dot-detection module that takes effective EIC symbols, which have been generated by processing an image containing the EIC symbols, as input and produces EIC dots as output by obtaining graylevels of selected positions of the EIC symbols;

an EIC-symbol-orientation-determination module that takes the EIC dots as input and produces rotated EIC dots as output by determining which grid cells correspond to the EIC symbols and by determining which direction is a correct orientation of the EIC symbols; and

an EIC-bit-extraction module that takes the rotated EIC dots as input and produces EIC bits as output based on graylevels of selected positions of the rotated EIC dots.

2. The system of claim 1, wherein the EIC-dot-detection module detects black dots from the obtained graylevels of selected positions of the EIC symbols.

3. The system of claim 2, wherein the EIC-bit-extraction module extracts EIC bits from the rotated EIC dots based on positions of black dots in the rotated EIC dots.

4. The system of claim 3, wherein the EIC-bit-extraction module extracts EIC bits based on whether a predetermined number of neighboring dots of a black dot in the rotated EIC dots are valid.

5. The system of claim 1, wherein the EIC-symbol-orientation-determination module generates an updated homography matrix with orientation information that transforms a coordinate system of a section of an EIC symbol array encompassing the image to a coordinate system of the image.

6. The system of claim 1, wherein the EIC-bit-extraction module produces as output respective confidence values that correspond to the EIC bits.

7. The system of claim 1, wherein the EIC-symbol-orientation-determination module determines which grid cells correspond to the EIC symbols and which direction is a correct orientation of the EIC symbols by determining how many black dots appear at orientation-dot positions in the EIC dots.

8. A computer-readable medium containing computer-executable instructions for recognizing embedded interaction code (EIC) symbols by performing steps comprising:

generating EIC dots based on effective EIC symbols, which have been generated by processing an image containing the EIC symbols, by obtaining graylevels of selected positions of the EIC-symbols;

generating rotated EIC dots based on the EIC dots by determining which grid cells correspond to the EIC symbols and by determining which direction is a correct orientation of the EIC symbols;

updating a homography matrix with orientation information based on the EIC dots; and

extracting EIC bits from the rotated EIC dots based on graylevels of selected positions of the rotated EIC dots.

9. The computer-readable medium of claim 8, containing further computer-executable instructions for detecting black dots from the obtained graylevels of selected positions of the EIC symbols.

10. The computer-readable medium of claim 9, containing further computer-executable instructions for extracting EIC bits from the rotated EIC dots based on positions of black dots in the rotated EIC dots.

11. The computer-readable medium of claim 8, containing further computer-executable instructions for extracting EIC bits based on whether a predetermined number of neighboring dots of a black dot in the rotated EIC dots are valid.

12. The computer-readable medium of claim 8, wherein the updated homography matrix transforms a coordinate system of a section of an EIC symbol array encompassing the image to a coordinate system of the image.

13. The computer-readable medium of claim 8, containing further computer-executable instructions for generating respective confidence values that correspond to the EIC bits.

14. The computer-readable medium of claim 8, containing further computer-executable instructions for determining which grid cells correspond to the EIC symbols and which direction is a correct orientation of the EIC symbols by determining how many black dots appear at orientation-dot positions in the EIC dots.

15. A system for recognizing embedded interaction code (EIC) symbols, the system comprising:

means for generating EIC dots based on effective EIC symbols, which have been generated by processing an image containing the EIC symbols, by obtaining graylevels of selected positions of the EIC-symbols;

means for generating rotated EIC dots by determining which grid cells correspond to the EIC symbols and by determining which direction is a correct orientation of the EIC symbols;

means for updating a homography matrix with orientation information based on the EIC dots; and

means for extracting EIC bits from the rotated EIC dots based on graylevels of selected positions of the rotated EIC dots.

16. The system of claim 15, further comprising means for detecting black dots from the obtained graylevels of selected positions of the EIC symbols.

17. The system of claim 15, further comprising means for extracting EIC bits from the rotated EIC dots based on positions of black dots in the rotated EIC dots.

18. The system of claim 15, further comprising means for extracting EIC bits based on whether a predetermined number of neighboring dots of a black dot in the rotated EIC dots are valid.

19. The system of claim 15, further comprising means for generating respective confidence values that correspond to the EIC bits.

20. The system of claim 15, further comprising means for determining which grid cells correspond to the EIC symbols and which direction is a correct orientation of the EIC symbols by determining how many black dots appear at orientation-dot positions in the EIC dots.