Embedding supplemental data in an encoded signal, such as audio / video watermarks

• US 6,157,330 A
• Filed: 01/26/1998
• Issued: 12/05/2000
• Est. Priority Date: 01/27/1997
• Status: Expired due to Term

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Nuijten, Petrus A. C. M., Bruekers, Alphons A. M. L., Oomen, Arnoldus W. J., Depovere, Geert F. G.
• Primary Examiner(s): WAMSLEY, PATRICK G
• Application Number:
  US09/013,540
• Time in Patent Office: 1,044 Days
• Field of Search: 380/54, 380/51, 380/59, 380/4, 380/5, 380/203, 341/143, 382/238, 382/100, 700/39, 283/113, 326/8, 399/366
• US Class Current: 341/143
• CPC Class Codes: G06T 1/0035 Output size adaptive watermarking
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00891 embedded in audio data
• CPC Class Codes: G11B 2020/00065 Sigma-delta audio encoding
• CPC Class Codes: H04N 19/00 Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• 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

Method of embedding watermarks in a signal encoded by an encoder having a feedback loop, for example, a sigma-delta modulator (21,22,23). A digital watermark pattern (w) is embedded in the signal (z) by modifying selected samples (for example, replacing every 100th bit) of the encoded signal (y) by samples of the watermark pattern. The circuit (24) for modifying the samples is located inside the loop of the encoder. The effect of watermarking is thus compensated in subsequent encoding steps and the signal-to-noise ratio is only slightly affected.

Claims

1. A method of embedding supplemental data in an encoded signal, comprising the steps of:

combining an input signal with a modified signal to produce a combined signal;

encoding the combined signal in accordance with a given encoding process to produce an encoded signal; and

modifying the encoded signal to represent the supplemental data to produce the modified signal.

2. The method of claim 1, wherein the encoding includes unity bit encoding.

3. The method of claim 2, wherein the encoding includes sigma-delta modulation.

4. The method of claim 1, wherein the step of modifying the encoded signal includes the replacement of selected samples of the encoded signal by samples of the supplemental data.

5. The method of claim 2, wherein the step of modifying the encoded signal includes the inversion of selected samples of the unity bit encoded signal, the embedded data being represented by the number of sample periods between successive inverted samples.

19. An encoded signal produced by the process of claim 1.

21. A storage medium having stored thereon a signal produced by the process of claim 1.

6. A method of extracting supplemental data from a received encoded signal in which selected predetermined samples are replaced by samples of the supplemental data, and including the step of selecting the samples in response to a predetermined selection signal.

7. The method of claim 6, wherein the selection signal is retrieved by detecting a synchronization pattern included in the supplemental data.

8. A method of extracting supplemental data from a received encoded signal, comprising the steps of:

encoding the original signal in accordance with a given encoding process including the step of feeding back the received encoded signal to control the encoding; and

comparing the encoded original signal and the received encoded signal, the difference between the signals representing the supplemental data.

9. The method of claim 8, wherein the supplemental data is represented by the number of sample periods between successive inverted samples, and further comprising the step of counting the number of sample periods between inverted samples to extract the supplemental data.

10. An arrangement for embedding supplemental data in an encoded signal, comprising:

means for combining an input signal with a modified signal to produce a combined signal;

an encoder for encoding the combined signal to produce an encoded signal;

means for modifying selected samples of the encoded signal to represent the supplemental data to produce the modified signal; and

a feedback loop connected to feed the modified encoded signal back to the combining means.

11. The arrangement of claim 10, wherein the encoder includes a unity bit encoder.

12. The arrangement of claim 11, wherein the encoder includes a sigma-delta modulator.

13. The arrangement of claim 10, wherein the means for modifying the encoded signal includes a multiplexer for replacing selected samples of the encoded signal by samples of the supplemental data.

14. The method of claim 11, wherein the means for modifying the encoded signal include an inverter for inverting selected samples of the unity bit encoded signal, the embedded data being represented by the number of sample periods between successive inverted samples.

15. An arrangement for extracting supplemental data from a received encoded signal in which selected predetermined samples are replaced by samples of the supplemental data, comprising:

register means for selecting the samples in response to a predetermined selection signal.

16. The arrangement of claim 15, further comprising means for detecting a synchronization pattern included in the supplemental data and means for generating the selection signal in response to the detection.

17. An arrangement for extracting supplemental data from a received encoded signal, comprising:

encoder means for encoding the original signal without the supplemental data and using the received encoded signal containing the supplemental data to control the encoding; and

means for comparing the encoded original signal with the received encoded signal, the difference between the signals representing the supplemental data.

18. The arrangement of claim 17, wherein the supplemental data is represented by the number of sample periods between successive inverted samples, and further comprising a counter for counting the number of sample periods between inverted samples to extract the supplemental data.

20. An encoded signal with embedded supplemental data, in which selected bits of the encoded signal have been inverted to represent the supplemental data with the number of bit periods between successive inverted bits representing the embedded data.

22. A method of embedding supplemental data in an signal, comprising the steps of:

encoding the signal in accordance with a given encoding process including feeding back the encoded signal to control the encoding; and

modifying the signal to represent the supplemental data after encoding the signal and before feeding back the encoded signal to control the encoding.

23. A method of embedding supplemental data in a signal, comprising the steps of:

unity bit encoding the signal in accordance with a given unity bit encoding process including feeding back the encoded signal to control the encoding; and

modifying the signal to represent the supplemental data before feeding back the signal to control the encoding.

24. A method of embedding unity bit supplemental data in a signal, comprising the steps of:

encoding the signal in accordance with a given encoding process including feeding back the encoded signal to control the encoding; and

combining unitary bit supplemental data into the signal before feeding the signal back to control the encoding.

25. A method of embedding supplemental data in a signal, comprising the steps of:

encoding the signal in accordance with a given encoding process;

combining supplemental data into the signal;

continuously feeding the combined and encoded signal containing the supplemental data back to the encoding process to control the encoding.