Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T1/00—General purpose image data processing
  • G06T1/0021—Image watermarking
  • G06T1/005—Robust watermarking, e.g. average attack or collusion attack resistant
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
  • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
  • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
  • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
  • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
  • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
  • H04N1/32154—Transform domain methods
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/32—Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
  • H04N1/32101—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
  • H04N1/32144—Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
  • H04N1/32149—Methods relating to embedding, encoding, decoding, detection or retrieval operations
  • H04N1/3232—Robust embedding or watermarking
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
  • H04N19/46—Embedding additional information in the video signal during the compression process
  • H04N19/467—Embedding additional information in the video signal during the compression process characterised by the embedded information being invisible, e.g. watermarking
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
  • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
  • H04N21/238—Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams
  • H04N21/2389—Multiplex stream processing, e.g. multiplex stream encrypting
  • H04N21/23892—Multiplex stream processing, e.g. multiplex stream encrypting involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
  • H04N21/80—Generation or processing of content or additional data by content creator independently of the distribution process; Content per se
  • H04N21/83—Generation or processing of protective or descriptive data associated with content; Content structuring
  • H04N21/835—Generation of protective data, e.g. certificates
  • H04N21/8358—Generation of protective data, e.g. certificates involving watermark
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2201/00—General purpose image data processing
  • G06T2201/005—Image watermarking
  • G06T2201/0065—Extraction of an embedded watermark; Reliable detection
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2201/00—General purpose image data processing
  • G06T2201/005—Image watermarking
  • G06T2201/0083—Image watermarking whereby only watermarked image required at decoder, e.g. source-based, blind, oblivious

Definitions

• This invention relates to a method and system for embedding information bits in a host signal.
• the embedding may be performed to determine origin of any perfect or imperfect copies of the composite (host plus message) signal, or to use the host signal as a cover for secret or covert communications, over a channel which is primarily meant for transmitting the host signal only.
• Data hiding or steganography is the art of hiding a message signal in a host signal, without any perceptual distortion of the host signal.
• the composite (host plus message) signal is also referred to as stego-signal.
• steganography is often confused with the relatively well-known cryptography, the two are but loosely related.
• Cryptography is about hiding the contents of a message.
• Steganography is about concealing the very fact that a message is hidden.
• Steganography may be considered as communication through subliminal channels, or secret communication.
• Multimedia content providers would be able to communicate with the compliant multimedia players (or Tenderers) through the subliminal, steganographic channel. This communication may control or restrict access of multimedia content, and carry out e-commerce for pay-per-use implementations.
• a typical application of data hiding for multimedia content delivery may involve the content providers supplying the raw multimedia data (say a full length movie) along with some hidden agents or control data .
• the job of the distributors would be to package the content in some suitable format (such as, MPEG) understandable by the player, for distribution of the multimedia through DVDs/CDs or live digital broadcasts, or by hosting web sites for downloads or streaming.
• the compliant multimedia players will typically be connected to the Internet.
• the content provider looses all control over how the multimedia is used/abused the moment it is acquired by another party.
• the key idea behind data hiding is to re-establish control whenever the content is used.
• the content provider by hiding an agent in his raw data, hopes to control access to his/her multimedia content. This can be done with the cooperation of the players, and an established protocol for communication between the content providers and the compliant multimedia players.
• Data hiding can be broadly classified into two categories depending on whether the original content is needed for extraction of the hidden bits: (1) non- oblivious methods need the original content for extracting the hidden bits; and (2) on the other hand, oblivious detection methods extract the hidden bits without any knowledge of the original.
• sequence of bits to be embedded viz. B
• bit sequence is converted to a signature sequence.
• signature sequence is embedded in the cover content by an embedding function to obtain the stego- content.
• data hiding methods can be classified into two categories, depending on the type of embedding and detecting operators.
• the first category includes methods where the embedding function adds the signature sequence linearly to stego-content, and the detector detects from the stego-content via correlative processing (these methods are referred to as Type I methods in data hiding literature).
• the second category the embedding function and the detector are non-linear, typically employing quantizers (these methods are referred to as Type II methods in data hiding literature).
• One of the important characteristics of the non-linear methods is their ability to suppress the noise due to the original content (or self-noise), even though the original content is not available at the receiver.
• the present invention provides a unique data hiding technique that substantially reduces the effect that noise, distortion or corruption of the host signal have on the detected signal so as to greatly enhance the integrity of steganography techniques employing oblivious detection of the hidden data.
• the crux of the invention is a class of methods referred to as Type III methods of which Types I and II are just special cases. An optimal choice of parameters for the proposed Type III methods depending on the engineering constraints, can substantially improve the performance of data hiding.
• a method for embedding a message signal in a host signal comprising the steps of: (a) embedding the message signal into the host signal, thereby producing a stego signal; and (b) detecting an estimate of the message signal from the stego signal; provided that the detecting step (b) is not an exact inverse of the embedding step (a), and the host signal cannot be exactly extracted from the stego signal.
• the embedding step (a) produces a value b, in the stego signal from a value a l in the host signal, and wherein the embedding step (a) comprises limiting
• the embedding step (a) employs a continuous periodic function to produce the stego signal
• the detecting step (b) employs a continuous periodic function to produce the estimated message signal.
• the continuous periodic function is a triangular function f(x) having a period ⁇ , wherein:
• the embedding step (a) produces a value b t in the stego signal from a value a l in the host signal and a value s, in the message signal, such that the embedding step (a):
• (ii) employs a continuous periodic function having a period ⁇
• ⁇ r, rem(—) ;
• the method of the present invention is particularly useful when the stego signal is corrupted or distorted prior to detecting step (b).
• a value b l in the stego signal is modified after the embedding step (a) to yield a value c ; in the corrupted or distorted stego signal, such that the detecting step (b):
• the embedding step (a) preferably (i) imposes a limit — on a magnitude
• This method comprising the step of: grouping the K information bits together to represent one of 2 L symbols, wherein each of the 2 L symbol is mapped to a basis vector or its negative of a 2 i_1 x 2 Z_I orthogonal transform matrix.
• the orthogonal transform matrix is obtained from a cyclic all-pass filter and its circular shifts.
• the cyclic all-pass filter is preferably obtained from a key.
• Fig. 1 is a block diagram of the data embedding, channel and detection operation according to the present invention
• Fig. 2 is a graph depicting a periodic triangular function employed by the detector D of Fig. 1;
• Fig. 3(a) is a graph demonstrating that the distortion introduced during the embedding the S in A (to obtain B ) of Fig. 1 in accordance with Type II will be
• Fig. 3(b) is a graph depicting the distribution of the distortion introduced in accordance with the method of the present invention.
• Fig. 3(c) is a graph depicting the distribution of the limiting noise t i
• the present invention is a method for efficient secure communication over subliminal channels provided by multimedia host signals like audio, ( images and video transmitted over any channel.
• the host signal may be transmitted over the Internet or distributed in storage mediums by other means or even transmitted over analog channels, such as, that used for analog television or radio broadcasts.
• the host signal is expected to undergo some distortion before it reaches one or many end points where it may be stored or rendered.
• the host signal may be any form of naturally occurring signals, such as, audio, image or video or artificially synthesized versions of them.
• the host signal may further be represented in some transform domain.
• the choice of the transform may depend on the nature of the application. For example, if the host signal is an image and is not expected to be re-scaled, resized or rotated, any unitary transform may be used. On the other hand, if the image is likely to undergo rotation, scaling and/or translation, a Rotation- Scale-Translation invariant transform may be used. If the image is cropped, data embedding may be performed in many blocks of the image, so that the hidden bits can be extracted even if one such block survives.
• the host signal can be coefficients of a one-to-one transform or a many-to-one transform.
• b N E(a N ,s N ) subject to the constraint that d(A,B) ⁇ P where d(A,B) is some distance measure of signals A and B , and P is the maximum permitted distortion of the host signal.
• the distance measure is the mean square error:
• FIGURE 1 The block diagram of data embedding, the channel and detection operation is shown in FIGURE 1.
• Type II methods Unlike Type I methods, the above two equations show that for Type II methods E and D are exact inverses. Additionally, unlike Type I methods, it is not possible to obtain A exactly, given B and S .
• the detector D where
• the choice of the parameter ⁇ is dictated by the distortion constraint P and the energy of the channel noise Z .
• ⁇ is a parameter, the choice of which is dictated by the distortion constraint P and the energy of the channel noise Z .
• sign (x) equals +1 if the quantity 'x' is positive and sign (x) equals -1 if the quantity 'x' is negative.
• a 2 will be ⁇ — .
• the distribution of the distortion introduced is
• the distribution of the limiting noise t j is shown in FIG. 3 c, and the average energy of the limiting noise is given by
• ⁇ From the values of ⁇ and signal energy P , ⁇ can be obtained by solving ⁇ 2 QA - 2 ⁇ ) ⁇ r 12 ⁇
• the mapping M:I ⁇ S in the preferred embodiment takes the following form.
• the bit sequence I of K bits is grouped into K/L L-bit symbols. Each L-bit symbol will be mapped to one of in
• K 8192, 6144, 4096, 2560, 1536, 896, 512, 288, and 160 bits respectively.
• L bits corresponding to each symbol are assumed to represent a decimal number between 1 and 2 L ⁇ X . This number is used as the index of the basis vector to be chosen.
• the random seed (or key) is used to generate uniformly distributed random sequence
• the — - 1 random numbers define the phase of the discrete Fourier
• DFT discrete Fourier transform
• the cyclic all-pass filter H is obtained by inverse Discrete Fourier Transform as
• Each segment of length Q of the signature sequence S of length N carries information pertaining to one symbol between 0 and 2Q-1.
• DFT Discrete Fourier Transform
• IDFT Inverse DFT
• I e is the estimate of the hidden bit sequence I.

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• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Computer Security & Cryptography (AREA)
• Editing Of Facsimile Originals (AREA)

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• 2001
  • 2001-08-02 EP EP01956130A patent/EP1317809A4/de not_active Withdrawn
  • 2001-08-02 AU AU2001278163A patent/AU2001278163A1/en not_active Abandoned
  • 2001-08-02 WO PCT/US2001/024468 patent/WO2002013436A1/en active Application Filing
  • 2001-08-02 JP JP2002518669A patent/JP2004506379A/ja active Pending

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