Method for inserting binary messages in a digital image

• US 20030048924A1
• Filed: 09/04/2002
• Published: 03/13/2003
• Est. Priority Date: 09/04/2001
• Status: Active Grant

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Petitjean, Guillaume
• Granted Patent: US 7,295,678 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/3224 in edge regions
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes

Abstract

A method and a system for inserting at least one binary code in a digital image, including converting the code into a modification of contours of objects in the image.

Claims

1. A method for inserting at least one binary code in a digital image comprising converting the code into a deformation of contours of objects in the image.

2. The method of claim 1, including the steps of:

detecting contours of objects in an original image;

isolating the contours from the rest of the image;

calculating Fourier descriptors of the contours;

modifying the Fourier descriptors of these contours according to the binary code to be inserted in the image; and

rebuilding the image while taking the new contours into account.

3. The method of claim 2, wherein the Fourier descriptors corresponding to the respective centers of gravity of the contours are not modified.

4. The method of claim 2, wherein the Fourier descriptors corresponding to the respective scale factors of the contours are not modified.

5. The method of claim 2, wherein only the modules of the Fourier descriptors are modified.

6. The method of claim 2, including, for each contour which is desired to be modified, the steps of:

selecting a pair of Fourier descriptors; and

modifying these descriptors so that their difference is respectively greater or smaller than a predetermined threshold according to whether the stored bit is 1 or 0.

7. The method of claim 6, wherein said threshold is set according to a compromise between the visibility of the modifications on the image and the sensitivity of the code insertion to image manipulations.

8. The method of claim 1, applied to the insertion of an element for identifying or authenticating the considered image.

9. The method of claim 1, applied to the insertion, in the image, of shooting characteristics of this image.

10. A method for extracting at least one binary code inserted in a digital image by implementing the method of claim 1, comprising applying, to the contours of an image, an extraction algorithm depending on the algorithm used to insert the code.

11. A digital image processing system intended to insert a binary code in an image, including means for implementing the method of claim 1.