Secure spread spectrum watermarking for multimedia data

• US 6,208,735 B1
• Filed: 01/28/1999
• Issued: 03/27/2001
• Est. Priority Date: 09/10/1997
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Research Institute, Inc. (NEC Corporation)
• Inventors: Cox, Ingemar J., Kilian, Joseph J., Shamoon, Talal G.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US09/239,240
• Time in Patent Office: 789 Days
• Field of Search: 380/54, 380/55, 380/200, 380/201, 380/202, 713/150, 713/168, 713/176, 283/17, 283/73, 283/113, 283/901, 341/51, 714/205, 382/212, 382/238, 707/101
• US Class Current: 380/54
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0063 in relation to collusion attacks, e.g. collusion attack resistant
• CPC Class Codes: G06T 2201/0081 whereby both original and watermarked images are required at decoder, e.g. destination-based, non-blind, non-oblivious
• CPC Class Codes: G11B 20/00891 embedded in audio data
• CPC Class Codes: H04H 20/31 using in-band signals, e.g. subsonic or cue signal
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467

Abstract

Digital watermarking of audio, image, video or multimedia data is achieved by inserting the watermark into the perceptually significant components of a decomposition of the data in a manner so as to be visually imperceptible. In a preferred method, a frequency spectral image of the data, preferably a Fourier transform of the data, is obtained. A watermark is inserted into perceptually significant components of the frequency spectral image. The resultant watermarked spectral image is subjected to an inverse transform to produce watermarked data. The watermark is extracted from watermarked data by first comparing the watermarked data with the original data to obtain an extracted watermark. Then, the original watermark, original data and the extracted watermark are compared to generate a watermark which is analyzed for authenticity of the watermark.

Claims

1. A method of inserting a watermark into data comprising the steps of:

obtaining a decomposition of data to be watermarked where said data to be watermarked is a representation of humanly perceivable material;

modifying the data to be watermarked by subjecting the data to at least one of distortion and tampering;

obtaining a decomposition of the modified data;

comparing the components of the decomposition of data to be watermarked with the components of the decomposition of the modified data; and

inserting a watermark into the data to be watermarked based upon said comparing.

2. A method of inserting a watermark into data as set forth in claim 1, where said inserting a watermark sequentially inserts a plurality of watermarks into perceptually significant components of the decomposition of data.

3. A method for extracting a watermark from data containing a watermark comprising the steps of:

obtaining a decomposition of data containing a watermark;

providing a decomposition of data to be watermarked which data to be watermarked is a representation of humanly perceivable material;

extracting a possible watermark as the difference between said decomposition of data containing a watermark and said decomposition of data to be watermarked at predetermined perceptually significant components of the decomposition of data to be watermarked; and

analyzing said extracted possible watermark to determine the presence of said watermark in said data containing a watermark.

4. A method extracting a watermark from data containing a watermark as set forth in claim 3, where said analyzing comprises measuring the similarity of the watermark (W) with the extracted possible watermark (W*).

5. A method of extracting a watermark from data containing a watermark as set forth in claim 4, where said similarity is measured according to the equation $\mathrm{sim}\left(W,W^{*}\right)=\frac{W^{*}·}{}$

WW*·

W*.

6. A method of inserting a watermark into data comprising the steps of:

providing a medium containing data;

obtaining a decomposition of the data to be watermarked;

modifying the data to be watermarked by subjecting the data to at least one of distortion and tampering;

obtaining a decomposition of the modified data;

comparing the components of the decomposition of data to be watermarked with the components of the decomposition of the modified data; and

inserting a watermark into the data to be watermarked based upon said comparing.

7. A method of inserting a watermark into data as set forth in claim 6, where said inserting a watermark sequentially inserts a plurality of watermarks into perceptually significant components of the decomposition of data.

8. A method for extracting a watermark from data containing a watermark comprising the steps of:

providing medium containing data including a watermark and data to be watermarked;

obtaining a decomposition of data including a watermark;

providing a decomposition of data to be watermarked;

extracting a possible watermark as the difference between said decomposition of data including a watermark and said decomposition of data to be watermarked at predetermined perceptually significant components of the decomposition of data to be watermarked; and

analyzing said extracted possible watermark to determine the presence of said watermark in said data containing a watermark.

9. A method of extracting a watermark from data containing a watermark as set forth in claim 8, where said analyzing comprises measuring the similarity of the watermark (W) with the extracted possible watermark (W*).

10. A method of extracting a watermark from data containing a watermark as set forth in claim 9, where said similarity is measured according to the equation $\mathrm{sim}\left(W,W^{*}\right)=\frac{W^{*}·}{}$

WW*·

W*.