Audio encoding to convey auxiliary information, and media embodying same

• US 8,355,514 B2
• Filed: 10/26/2007
• Issued: 01/15/2013
• Est. Priority Date: 11/18/1993
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey B.
• Primary Examiner(s): Paul, Disler
• Application Number:
  US11/925,261
• Publication Number:
  US 20080131083A1
• Time in Patent Office: 1,908 Days
• Field of Search: 381/73.1, 381/124, 380/252, 380/254, 380275-276, 382/232
• US Class Current: 381/73.1
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06Q 20/1235 with control of digital rights management [DRM]
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/40145 Biometric identity checks
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 1/0057 Compression invariant watermarking
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G07C 9/253 visually
• CPC Class Codes: G07D 7/0032 using holograms
• CPC Class Codes: G07D 7/004 using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: G07F 17/16 for devices exhibiting advertisements, announcements, pictures or the like
• CPC Class Codes: G07F 17/26 for printing, stamping, franking, typing or teleprinting apparatus ticket printing or the like apparatus G07F17/42
• CPC Class Codes: G07F 7/08 by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/086 by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: G07F 7/1016 Devices or methods for securing the PIN and other transaction-data, e.g. by encryption arrangements for secret communication, see H04L9/00
• CPC Class Codes: G07F 7/12 Card verification
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G11B 20/00007 Time or data compression or expansion audio compression based on psychoacoustics G10L19/00; data processing for reproducing audio data at different playback speeds G10L21/04; video compression H04N19/00; data compression per se H03M7/30
• 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 20/00094 : involving measures which result in a restriction to authorised record carriers
• CPC Class Codes: G11B 20/00115 : wherein the record carrier stores a unique medium identifier
• CPC Class Codes: G11B 20/00166 : involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
• CPC Class Codes: G11B 20/00181 : using a content identifier, e.g. an international standard recording code [ISRC] or a digital object identifier [DOI]
• CPC Class Codes: G11B 20/0021 : involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00884 : involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: G11B 20/00891 : embedded in audio data
• CPC Class Codes: G11B 20/10037 : A/D conversion, D/A conversion, sampling, slicing and digital quantisation or adjusting parameters thereof
• CPC Class Codes: G11B 20/10527 : Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/00014 : the compressed signal being an audio signal
• CPC Class Codes: G11B 2020/10546 : specifically adapted for audio data
• CPC Class Codes: G11B 2020/10555 : wherein the frequency, the amplitude, or other characteristics of the audio signal is taken into account
• CPC Class Codes: H04B 1/665 : using psychoacoustic properties of the ear, e.g. masking effect
• 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 1/32144 : embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32149 : Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32203 : Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 : involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32251 : in multilevel data, e.g. greyscale or continuous tone data
• 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 2005/91321 : the copy protection signal being a copy protection control signal, e.g. a record inhibit signal
• CPC Class Codes: H04N 2005/91335 : the copy protection signal being a watermark
• CPC Class Codes: H04N 2005/91342 : the copy protection signal being an authentication signal
• CPC Class Codes: H04N 2005/9135 : by superimposing the spectrally spread copy protection signal onto the video signal
• 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 2201/3226 : 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 2201/328 : Processing of the additional information
• CPC Class Codes: H04N 5/89 : using holographic recording H04N5/91 takes precedence
• CPC Class Codes: H04N 5/90 : on discs or drums
• CPC Class Codes: H04N 5/913 : for scrambling ; for copy protection
• CPC Class Codes: H04N 9/8042 : involving data reduction
• CPC Class Codes: H04N 9/8047 : using transform coding
• CPC Class Codes: H04N 9/8205 : involving the multiplexing of an additional signal and the colour video signal
• CPC Class Codes: Y10S 283/901 : Concealed data

Abstract

Methods of processing audio to convey auxiliary information hidden therein are provided. Various arrangements are disclosed. One alters data representing audio to include a sequence of bits of auxiliary information. The altering is based on a carrier signal and corresponding to the sequence of bits, and is based on a perceptibility threshold that varies within the data representing audio. Other arrangements are provided as well.

Claims

1. A method of embedding data in an audio signal, comprising:

providing a message comprising message bits;

associating carrier signals with the message bits;

modulating the carrier signals according to values of the associated message bits, wherein the modulating changes a property of the carrier signal to correspond with a desired value of the associated message bit;

adjusting the modulated carrier signals as a function of a perceptibility threshold computed from the audio signal where the carrier signals are to be embedded; and

combining the adjusted carrier signals with the audio signal.

2. The method of claim 1, wherein the message bits comprise a set of fixed bits used to calibrate a detector for extraction of other message bits.

5. The method of claim 1, wherein the modulating comprises changing the polarity of the carrier signals.

6. The method of claim 1, wherein the adjusting comprises scaling the carrier signal amplitude based on the perceptibility threshold computed from the audio signal.

3. The method of claim h wherein the carrier signals comprise noise sequences.

4. The method of claim 3, wherein the noise signals are generated by a sequence generator seeded by a key.

7. A method of detecting data embedded in an audio signal, the method comprising:

applying a carrier signal to the audio signal to produce an output signal including peaks corresponding to embedding locations of the carrier signal, wherein the peaks comprise positive and negative peaks;

analyzing, using a processor, the output signal to perform a registration of the embedding locations in the output signal; and

determining message values from the peaks at the embedding locations in the output signal.

8. The method of claim 7, wherein the applying comprises correlating a carrier signal with portions of the audio signal.

9. The method of claim 8, wherein the correlating comprises applying a matched filter.

10. The method of claim 7, further comprising weighting portions of the audio signal based on statistics of the audio signal.

11. The method of claim 7, wherein the analyzing comprises identifying a pattern of peaks.

12. The method of claim 7, wherein certain of the peaks are used to calibrate detection of other of the peaks.

13. The method of claim 7, wherein there are a plurality of different carrier signals, and wherein the plurality of different carrier signals are applied to the audio signal to produce the output signal.

14. The method of claim 7, wherein the applying a carrier signal to the audio signal comprises computing statistical features of the audio signal to produce the output signal.

15. The method of claim 14, wherein the statistical features comprise time averaged power of the audio signal.

16. The method of claim 7, further comprising filtering the audio signal using a model representing an effect of compressing the audio signal.

17. The method of claim 16, wherein the filtering weights the audio signal according to expected errors introduced by the compressing of the audio signal.

18. An apparatus, comprising:

one or more processors configured to;

receive a message comprising message bits;

associate carrier signals with the message bits;

modulate the carrier signals according to values of the associated message bits, wherein the modulating changes a property of the carrier signal to correspond with a desired value of the associated message bit;

adjust the modulated carrier signals as a function of a perceptibility threshold computed from the audio signal where the carrier signals are to be embedded; and

combine the adjusted carrier signals with the audio signal.

19. The apparatus of claim 18, wherein the message bits comprise a set of fixed bits used to calibrate a detector for extraction of other message bits.

20. The apparatus of claim 18, wherein the modulated carrier signals are adjusted by scaling the carrier signal amplitude based on the perceptibility threshold computed from the audio signal.