Watermark encoding method exploiting biases inherent in original signal

• US 6,381,341 B1
• Filed: 11/17/1999
• Issued: 04/30/2002
• Est. Priority Date: 05/16/1996
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B.
• Primary Examiner(s): Couso, Jose L.
• Application Number:
  US09/441,820
• Time in Patent Office: 895 Days
• Field of Search: 382/100, 382/232, 382/250, 382/284, 382/274, 395/135, 358/454, 358/448, 358/450, 358/142, 358/124, 380/4, 380/23, 380/25, 380/54, 283/6, 283/93, 283/94, 348/475, 235/494
• US Class Current: 382/100
• 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 2201/0064 for copy protection or copy management, e.g. CGMS, copy only once, one-time copy
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06V 30/40 Document-oriented image-based pattern recognition
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: H04N 1/00005 relating to image data
• CPC Class Codes: H04N 1/00037 Detecting, i.e. determining the occurrence of a predetermined state H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00079 remotely
• CPC Class Codes: H04N 1/32122 in a separate device, e.g. in a memory or on a display separate from image data
• CPC Class Codes: H04N 1/32149 Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 1/32288 Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
• CPC Class Codes: H04N 1/32352 Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• 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
• CPC Class Codes: H04N 2201/3205 of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3207 of an address
• CPC Class Codes: H04N 2201/3225 : of data relating to an image, a page or a document
• CPC Class Codes: H04N 2201/3226 : of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• 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
• CPC Class Codes: H04N 2201/3271 : Printing or stamping
• CPC Class Codes: H04N 2201/3274 : Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 2201/3284 : for error correction

Abstract

Source materials to be watermarked already have variations in their characteristics that may tend to aid the watermark encoding. Where such favorable variations exist, relatively less watermark energy can be applied.

Claims

1. A method of processing a sampled data signal to steganographically encode plural-bit auxiliary data therein, the method including changing plural signal characteristics of the sampled data signal to embed the plural-bit auxiliary data therein, characterized by:

analyzing biases already existing in the signal characteristics of the sampled data signal to determine whether such biases tend toward values associated with the plural-bit auxiliary data values, and

if so, changing the signal characteristics relatively less to encode the auxiliary data into the sampled data signal, said changes being non-zero in value.

2. The method of claim 1 in which the sampled data signal represents visual information.

3. The method of claim 1 in which the signal characteristics comprise sample values.

4. The method of claim 3 which includes:

analyzing biases already existing at plural locations in the sampled data to determine whether such biases aid in the encoding; and

if so, changing the sampled data at such locations relatively less to encode the auxiliary data, and

if not, changing the sampled data at such locations relatively more to encode the auxiliary data.

5. The method of claim 4 in which said locations comprise plural adjoining samples rather than single samples.

6. The method of claim 1 in which the plural-bit auxiliary data includes device control data operative to trigger a response in a consumer appliance, such as enabling or disabling certain operations, depending on the particular plural-bit auxiliary data.

7. A storage medium having a processed data signal produced by the method of claim 1 thereon, the plural-bit auxiliary data encoded therein serving to trigger some operation in a consumer appliance, such as enabling or disabling certain operations, depending on the particular plural-bit auxiliary data.

8. A storage medium having stored thereon a processed data signal produced by the method of claim 1.

9. The method of claim 1 in which the sampled data signal represents audio information.

10. The method of claim 9 in which the signal characteristics comprise sample values.

11. The method of claim 10 which includes:

analyzing biases already existing at plural locations in the sampled data to determine whether such biases aid in the decoding; and

if so, changing the sampled data at such locations relatively less to encode the auxiliary data; and

if not, changing the sampled data at such locations relatively more to encode the auxiliary data.

12. The method of claim 11 in which said locations comprise plural adjoining samples rather than single samples.

13. The method of claim 9 in which the plural-bit auxiliary data includes device control data operative to trigger a response in a consumer appliance, such as enabling or disabling certain operations, depending on the particular plural-bit auxiliary data.

14. A storage medium having a processed data signal produced by the method of claim 9 thereon, the plural-bit auxiliary data encoded therein serving to trigger some operation in a consumer appliance, such as enabling or disabling certain operations, depending on the particular plural-bit auxiliary data.

15. A storage medium having stored thereon a processed data signal produced by the method of claim 9.

20. The method of claim 1 wherein the signal characteristics are changed by varying a gain value applied to an auxiliary signal embedded into the sampled data signal such that the gain value is dependent on the auxiliary data to be embedded in the sampled data signal.

21. The method of claim 20 wherein the auxiliary signal is embedded into the sampled data signal by adding the auxiliary signal to the sampled data signal.

22. The method of claim 21 wherein the auxiliary signal and the sampled data signal are added in a perceptual domain of the sampled data signal.

23. A computer readable medium on which is stored software for performing the method of claim 1.

24. An auxiliary data decoder for decoding the auxiliary data embedded into sampled data signals according to the method of claim 1.

16. A method of processing a sampled data signal to steganographically encode auxiliary data therein, each sample having a value, the method including changing plural sample values to thereby bias same, characterized by:

analyzing biases already existing in the signal to determine whether such biases naturally tend toward signal characteristics associated with the plural-bit auxiliary data being encoded, and

where such natural biases are found, changing the sample values relatively less than would otherwise be the case.

25. The method of claim 16 wherein the sample values are changed by varying a gain value applied to an auxiliary signal embedded into the sampled data signal such that the gain value is dependent on the auxiliary data to be embedded in the sampled data signal.

26. The method of claim 25 wherein the auxiliary signal is embedded into the sampled data signal by adding the auxiliary signal to the sampled data signal.

27. The method of claim 26 wherein the auxiliary signal and the sampled data signal are added in a perceptual domain of the sampled data signal.

28. A computer readable medium on which is stored software for performing the method of claim 16.

29. An auxiliary data decoder for decoding the auxiliary data embedded into sampled data signals according to the method of claim 16.

17. A method of processing an input data signal representing audio or imagery so as to yield a desired output data signal having auxiliary data encoded therein, the auxiliary data being encoded by adding a low-amplitude signal to the input data signal, the method being characterized by assessing attributes of the input data signal and, where such attributes tend to mimic attributes of the desired output data signal that correspond to encoded auxiliary data values, adding relatively less of said low-amplitude signal thereto.

18. The method of claim 17 that includes, where such attributes tend to be contrary to attributes of the desired output signal, adding relatively more of said low-amplitude signal thereto.

19. The method of claim 17 in which the input and output data signals comprise samples, and said attributes comprise relative biases of samples relative to neighboring samples.

30. A decoder for decoding auxiliary data that has been embedded into an input signal representing audio or imagery, where the auxiliary data has been embedded by processing the input data signal so as to yield a desired output data signal having auxiliary data encoded therein, the auxiliary data being encoded by adding a low-amplitude signal to the input data signal, including assessing attributes of the input data signal and, where such attributes tend to mimic attributes of the desired output data signal that correspond to encoded auxiliary data values, adding relatively less of said low-amplitude signal thereto.

31. The decoder of claim 30 wherein the amount of the low-amplitude signal added to the input signal is controlled by applying a gain to the low-amplitude signal that is a function of the input signal and the auxiliary data encoded into the input signal.

32. A method of embedding an auxiliary message into an original media signal to create an embedded media signal in which the auxiliary message is substantially imperceptible, the method comprising:

providing auxiliary message data for embedding into the original media signal, where the auxiliary message data includes two or more message elements, each of the message elements corresponding to characteristics of the embedded media signal;

adjusting characteristics of the original media signal to embed the message elements, including evaluating a characteristic of the original media signal to determine whether the characteristic is already biased toward the characteristic corresponding to a message element in the embedded media signal, changing the characteristics of the original media signal by lesser or greater amounts depending on whether the characteristics are already biased toward or away from the characteristics of the embedded media signal.

33. The method of claim 32 wherein the characteristics are adjusted by varying a gain value.

34. The method of claim 33 wherein the gain value is a function of the original media signal and auxiliary data to be encoded.

35. The method of claim 34 wherein the gain value is applied to an auxiliary signal and added to the media signal in a perceptual domain of the media signal to create the embedded media signal.

36. A computer readable medium on which is stored software for performing the method of claim 32.

37. A auxiliary data decoder for decoding data embedded into media signals according to the method of claim 32.