Sony United Kingdom Limited

Daniel Warren Tapson

Jason Charles Pelly

Stephen Mark Keating

Daniel Luke Hooper

Jonathan James Stone

Mark Julian Russell

Andrew Robert Taylor

Clive Henry Gillard

Michael John Williams

Andrew Collins

Morgan William Amos David

Ian McLean

Emmanuel Alves-Moreira

The bitstream includes digital codes representing an information signal. At least one digital code is selected. The code occupies a part of the bitstream which is to contain at least one watermark code which represents a watermark perceptible in the information signal. The selected digital code(s) are removed from the said part of the bitstream. The watermark code(s) are put in the said part of the bitstream in place of the selected code(s). The number of bits of the selected code(s) removed from the said part of the bitstream is greater than or equal to the number of bits of the said watermark code(s) put in the said part. The removed selected code(s) are appended to an end of the bitstream and/or placed in watermark user data fields created in the bitstream.

Modifying bitstreams

An encoding data processing apparatus generates a video material item marked copy by embedding a payload data word into the video material item. The video material item includes plural video frames. A code word generator generates a water mark code word from the payload data word and reads data representing the water mark code word into a shuffle data store. A shuffle processor generates pseudo randomly at least one address within an address space of the shuffle data store for each video frame and reads data representing part or parts of the water mark code word out from the data store at locations identified by the pseudo randomly generated address. A data embedding processor receives the video material item and embeds the data representing the part or parts of the water mark code word read out from the shuffle data store for each frame into a corresponding frame of the video material item.

Encoding and detecting apparatus

A water marking system generates a water marked image frame for conveying a payload data word by combining at least one image frame with a two-dimensional water mark pattern. The water mark pattern includes plural regions each associated with one of symbols of the payload data word. Each region includes a two dimensional water mark block selected from a predetermined set of possible water mark blocks to represent the value of the payload data symbol associated with that region. A detecting data processing apparatus detects the payload data from a received water marked image frame, which has been encoded by utilizing a block match prior probability calculator operable to correlate each region of the water marked image frame with each of the water mark blocks from the set of water marked blocks) to form for each region a set of probability surfaces.

Data processing apparatus and method

A data processing apparatus is operable to identify one of a plurality of code words present in a watermarked version of a material item. The marked version is formed by combining each of a plurality of parts of a code word with one of a plurality of units from which the material item is comprised. The apparatus comprises a recovery processor operable to recover at least one part of the code word from a corresponding unit of the marked material item, and a correlator. The correlator is operable to generate for the marked material unit, a dependent correlation value for the part of the code word recovered from the material unit and the corresponding part of at least one of the re-generated code words from the set. A detector is operable to determine whether at least one of the code words is present in the marked material item from the dependent correlation value for the part of the code word exceeding a predetermined threshold. The data processor may detect the presence of the code word with improved probability, in particular when parts of the material have been corrupted.

A method of detecting a version of input data content, there being a plurality of different versions of said data content, in which:

Data content identification

An apparatus including a transformer for transforming transform domain data into time domain data and a combiner for receiving material and combining said time domain data with said material to form data embedded material. Hence, the material is not subject any transformation at all.

Embedding data in material

An encoding data processing apparatus is arranged to generate a marked copy of an item of material by introducing at least one code word into a copy of the material item, the code word being arranged to identify a payload data word. The encoding apparatus comprises an encryption circuit operable to receive a payload encryption key and to receive the payload data word, and to encrypt the payload data word using the payload encryption key. A pseudo random number generator receives the encrypted payload data and a finger print key and generates the code word having a plurality of code word coefficients using the encrypted payload as a seed for the pseudo random number generator and the finger print key. A combiner combines the code word with the material to form the marked copy of the material item. The encoding apparatus may form part of a media terminal for marking material items with the code words, when the material items are to be reproduced. A more secure system for reproducing watermarked material can be formed using the encoding apparatus in which the payload data is encrypted and used as a seed for the pseudo random number generator with the finger print key to generate the code word coefficients. The code word is thereby generated from a finger print key and an encrypted seed, which provides an improved level of security against an attack aimed at compromising correction detection of a code word in a mark material item.

An encoding data processing apparatus is arranged to generate a marked copy of an image by introducing a code word into a copy of the image. The apparatus comprises a code word generator operable to generate the code word. The encoding apparatus includes an image perception analyser and a strength adapter. The image perception analyser is operable to receive the image and to generate weighting factors. A combiner is operable to combine the weighted code word with the image. The image perception analyser includes a contrast masking engine, a smoothness compensation engine and a compensation combiner. The weighting factor has an effect of reducing the code word coefficients for image parts having lower relative contrast measures. A compensation combiner is operable to combine the compensation factors with the weighting factor. The likelihood of a code word being perceivable when the code word is combined with an image is reduced.

Encoding apparatus and method

A material distribution apparatus, comprising a material server including a data introduction processor operable to introduce data into material to be distributed with the effect that the introduced data is at least difficult to perceive in the material, and a material impairment processor operable to introduce a reversible impairment into the material. A communications network distributes the impaired material to at least one client processor which includes an impairment reversing processor operable to reverse the impairment of the material to produce client restored material.

Material distribution apparatus

A method includes generating, for a signal sample, first and second gaussian likelihood functions describing a likelihood of a watermark codeword coefficient value embedded into the signal sample being, respectively, positive and negative. The first gaussian likelihood function has a mean defined by a sum of a local mean value and a watermark strength value and a standard deviation defined by a local standard deviation. The second gaussian likelihood function has a mean defined by a difference between the local mean value and the watermark strength value and the standard deviation defined by the local standard deviation. The method also includes detecting a watermark in an image signal based on a probability of watermark codeword coefficients added to the signal sample being one of positive or negative, the probability being calculated from the first gaussian likelihood function and the second gaussian likelihood function.

A data processing apparatus includes a registration processor that divides a frame of a water marked image into a plurality of image blocks. For each of the image blocks, an observed probability of possible distortion vectors representing shifts of the image block with respect to positions of the block in the original version of the image is estimated. For each of the image blocks, forward and backward probability distribution estimates of possible distortion vectors within the image block are generated recursively from the respective observed probability of distortion vectors for the image block and forward and backward probability distribution estimates determined respectively from previous and subsequent image blocks for a predetermined path through the blocks. For each image block, the forward and backward probability distribution estimates and the observed probability of distortion vector are combined to form a most likely distortion vector estimate.

According to the present invention there is provided an encoding data processing apparatus for generating a marked copy of an item of material by introducing code words into a copy of the material item. The code words are arranged to identify a data word from a set of data words having at least two fields. The apparatus comprises a code word generator operable to generate at least two code words having a plurality of code word coefficients, each of the code words being independently generated from a different code word seed, and an encoding processor operable to combine the code word coefficients with the material item. One of the code words is selected from a first set in dependence upon a value of a first of the data fields and one of the code words is selected from a second set in dependence upon a value of a second of the data fields. The values of the first data field are associated with the first set of code words and values of the second data field are associated with the second set of code words, the second set of code words being selected in dependence upon the value of the first data field. By arranging for a value of a second or subsequent data field to be selected in dependence upon a value of the first or a previous data field, then a detecting complexity for unambiguously identifying the data word can be substantially reduced.

A watermarking system comprises an encoding data processor operable to generate at least one marked version of an original item of material by introducing one of a predetermined set of code words into a copy of the original material item. The encoding data processor is arranged to form other code words of the set by cyclically shifting a first code word. The system includes a detecting data processor operable to identify the code word in the marked material item. The detecting data processor is operable to recover the code word from the marked material item and to form a Fourier transform of the recovered code word and a Fourier transform of the first code word of the set. The data detecting processor forms correlation samples by forming an inverse transform of a combination of the recovered and the first code word. Each of the correlation value samples provides the correlation value for one of the set of code words. A computationally efficient way of calculating the correlation for each code word in the set is thereby provided. As a result a time taken to detect a code word present in a marked material item is improved. The watermarking system finds particular application in identifying a point of distribution of pirate copies of video material generated by capturing the watermarked image, using, for example, a camcorder in a cinema.

A recording system for applying access control processing to input data content and for recording access-controlled data content on a computer readable storage medium. The recording system includes an encryption apparatus for encrypting portions of the input data content and an access control memory device which securely stores information from which a private key of a public key/private key pair associated with a data content recording user or user group is derivable. The encryption apparatus and the access control memory device co-operate to provide access control data including content recorder access control data and default access control data. The default content access control data provides the same level of access to the input data content as the level of access available to the data content recording user/user group. A recorder is provided for recording the encrypted input data content and the content access control data on the computer readable storage medium.

Access control for digital content

A system for watermarking and distributing material includes a data processing apparatus, which operates as a watermark encoder. The data processing apparatus is operable to process an original material item to form a reduced-bandwidth-version of the material item, marked with a code word from a predetermined set of code words. The data processing apparatus is operable to form an impaired version of the material item from which a marked representation of the original material item can be formed. The impaired version is formed by subtracting the reduced-bandwidth-version of the material item from a copy of the original material item. As such, the impaired version can be mass distributed, but a representation of the original material item cannot be formed without the reduced-bandwidth-version of the material item. By watermarking the reduced-bandwidth-versions, a representation of the material item, formed by combining one of the marked reduced-bandwidth-versions with the impaired material item, can be uniquely identified. However, only a low bandwidth part of the material item need be watermark encoded, which is more easily distributable to individual recipients than watermarked copies of the original material item.

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Basingstoke, United Kingdom

Daniel Warren Tapson