Embedding Data in Images

• US 20090136082A1
• Filed: 11/27/2007
• Published: 05/28/2009
• Est. Priority Date: 11/27/2007
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Zandifar, Ali, Liu, Che-Bin, Xiao, Jing
• Granted Patent: US 8,009,862 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0021 Image watermarking

Abstract

Disclosed are embodiments of systems and methods for embedding and/or extracting data from images. In embodiments, an image may be segmented into regions, and characters or other image groups within a segmented region may be determined to be embedding sites. A data vector may be embedded into a set of corresponding ordered embedding sites by representing each data element as different intensity values assigned to the pixels within one portion of an embedding site relative to the pixels in another portion of the embedding site. In embodiments, embedded data may be extracted from an image by extracting and decoding a set of bit values from a set of identified and ordered embedding sites.

Claims

1. A method for embedding data into an image, the method comprising:

identifying a set of ordered embedding sites in the image wherein an embedding site comprises a plurality of pixels;

encoding the data into a vector comprising a set of ordered values wherein each unique value from the set of ordered values correlates to a unique embed pattern comprising a unique intensity difference between a first region of pixels and a second region of pixels;

associating the set of ordered values with at least some of the ordered embedding sites from the set of ordered embedding sites; and

embedding the data into the image by;

for an ordered value in the set of ordered values, applying its correlated unique embed pattern to its associated embedding site from the set of ordered embedding sites.

2. The method of claim 1 wherein the step of identifying a set of ordered embedding sites in the image comprises:

segmenting the image into regions;

identifying a plurality of connected components comprising pixels from one of the regions;

identifying a plurality of embedding sites within the plurality of connected components; and

assigning an order to the plurality of embedding sites.

3. The method of claim 2 wherein the step of identifying a plurality of embedding sites within the plurality of connected components comprises:

selecting a plurality of candidate embedding sites from the plurality of connected components wherein a candidate embedding site comprises at least one connected component; and

selecting an embedding site based upon at least one characteristic of a candidate embedding site from the plurality of candidate embedding sites wherein the at least one characteristic applies to the size, shape, or position of a bounding box of the candidate embedding site.

4. The method of claim 3 wherein assigning an order to the plurality of embedding sites comprises using the positions of embedding sites within the plurality of embedding sites to assign an order.

5. The method of claim 4 wherein using the positions of embedding sites within the plurality of embedding sites to assign an order comprises:

ordering a plurality of groups of embedding sites by performing a first direction sweep on the image; and

performing a second direction sweep on at least one group of embedding sites within the plurality of groups to order a set of embedding sites within the group.

6. The method of claim 5 wherein the step of ordering a plurality of groups of embedding sites comprises:

ordering a first plurality of groups of embedding sites by performing a first direction sweep on the image;

rotating the image by a first angle of rotation;

ordering a second plurality of groups of embedding sites by performing the first direction sweep on the rotated image; and

determining which of the first and the second plurality of groups has a greater number of groups of embedding sites and selecting that plurality of groups of embedding sites as the plurality of groups of embedding sites.

7. The method of claim 1 wherein encoding the data into a vector comprises:

including an indicator prefix with the data; and

bit-encoding the indicator prefix and the data into the vector.

8. The method of claim 7 further comprising the step of encoding the vector using an error-correcting code.

9. The method of claim 1 wherein embedding the data into the image further comprises dilating pixels in the region of the associated embedding site that corresponds to the region of the unique embed pattern that has a greater intensity value.

10. A computer readable medium having instructions for performing the method of claim 1.

11. A method for embedding a data value into an embedding site comprising pixels from an image, the method comprising:

segmenting the image into regions;

identifying a plurality of connected components comprising pixels from one of the regions;

identifying a plurality of candidate embedding sites within the plurality of connected components wherein a candidate embedding site comprises at least one connected component;

selecting the embedding site from the plurality of candidate embedding sites based upon at least one characteristic of a candidate embedding site from the plurality of candidate embedding sites; and

associating the data value with the embedding site wherein the data value correlates to a unique embed pattern comprising a unique intensity difference between pixels from a first region of the embedding site and pixels from a second region of the embedding site.

12. The method of claim 11 wherein the at least one characteristic applies to a bounding box of the candidate embedding site.

13. The method of claim 12 wherein selecting the embedding site from the plurality of candidate embedding sites based upon at least one characteristic of a candidate embedding site comprises:

responsive to the bounding box having a width that exceeds a first threshold, and a height that exceeds a second threshold, selecting the embedding site.

14. The method of claim 12 wherein selecting the embedding site from the plurality of candidate embedding sites based upon at least one characteristic of a candidate embedding site comprises:

defining a first value that is greater than zero and less than one; and

responsive to the bounding box having a width less than its height multiplied by the first value, not selecting the embedding site.

15. The method of claim 12 wherein selecting the embedding site based upon at least one characteristic of a candidate embedding site comprises:

defining a second value that is greater than zero and less than one; and

responsive to the bounding box having a height less than its width multiplied by the second value, not selecting the embedding site.

16. The method of claim 12 wherein selecting the embedding site based upon at least one characteristic of a candidate embedding site comprises:

responsive to corner of the bounding box intersecting a different bounding box of a different embedding site, not selecting the embedding site and the different embedding site.

17. A computer readable medium having instructions for performing the method of claim 11.

18. A system for embedding a data vector into an image comprising pixels, the system comprising:

an encoder, coupled to receive data, that encodes the data into a data vector; and

a message embedder, coupled to receive the image and the data vector, that embeds the data vector into the image, the message embedder comprising;

an embed pattern embedder, coupled to receive an ordered set of embedding sites, that embeds data into the image by encoding the data vector into a set of ordered values wherein each unique value from the set of ordered values correlates to a unique embed pattern comprising a unique intensity difference between a first region of pixels and a second region of pixels.

19. The system of claim 18 wherein encoding the data into a data vector comprises:

including an indicator prefix with the data; and

bit-encoding the indicator prefix and the data into the data vector.

20. The system of claim 18 wherein the message embedder further comprises:

an embedding site selector, coupled to receive the image, that identifies a set of embedding sites in the image wherein an embedding site comprises a plurality of pixels; and

an embedding site ordering processor, coupled to receive the set of embedding sites, that orders the set of embedding sites.

21. The system of claim 20 wherein identifying a set of embedding sites in the image comprises:

segmenting the image into regions;

identifying a plurality of connected components comprising pixels from one of the regions;

identifying a plurality of candidate embedding sites within the plurality of connected components wherein a candidate embedding site comprises at least one connected component; and

identifying an embedding site from the plurality of candidate embedding sites based upon at least one characteristic of a candidate embedding site from the plurality of candidate embedding sites.

22. The system of claim 20 wherein ordering the set of embedding sites comprises using the positions of embedding sites within the plurality of embedding sites to assign an order.