Abstract: An image processing apparatus is operable to embed data into an image. The apparatus comprises a combining processor operable to introduce the data into a transform domain representation providing a plurality of sub-bands divided by spatial frequency components, and, in combination with a transform processor, to combine the data with the image in one of a transform domain form, the transform processor generating a transform domain form of the image, the data being combined with the image by the combining processor in the transform domain, and the transform processor generating a spatial domain representation of the combined image and data, or a spatial domain form of the image, the transform processor generating a spatial domain representation of the transform domain data, the data being combined with the image by the combining processor in the spatial domain.

Abstract: Material is represented by transform coefficients represented by digital numbers. A method of perceptibly watermarking the material comprises the steps of: changing representations of the said numbers according to an invertible algorithm without changing the number of bits in the said numbers; and encoding the changed n bit numbers to effect compression encoding of the material.

Abstract: A method of embedding data in material comprises the steps of: embedding data in original material to produce data embedded material; removing the watermark from the data embedded material to produce recovered material; comparing the original and recovered material to determine the differences and locations of differences therebetween; and storing the said locations and corrections which correct the said differences. A method of removing the data embedded in the material, comprises the steps of: removing the data from the material to produce recovered material; deriving the said corrections and locations from the said store; and using the corrections to correct the recovered material at the said locations.

Abstract: The present invention controls copying of an information signal, comprises the steps of prior to recording and/or transmission, applying to the information signal a substantially imperceptible modification representing copy control data including a password securely encoded according to a predetermined algorithm; upon reproduction for copying by a user, deriving (S1, S3) the copy control data from the modified information signal; comparing (S8, S9, S11, S13, S15) the derived securely encoded password with a reference password securely encoded according to a predetermined algorithm; and enabling (S5) copying of the information signal if the securely encoded password derived from the information signal and the securely encoded reference password have a predetermined relationship, otherwise disabling copying (S7). The reference password is sent to the user via a channel, which is separate from a channel used to send the information signal to the user.

Abstract: An apparatus for detecting and recovering data embedded in information material, the data having been embedded in the material in a transform domain representation by arranging for the data to modulate a predetermined data sequence to form modulated data and combining the modulated data with the material. The apparatus includes a transform processor operable to transform the material into the transform domain representation, and a correlation processor operable to correlate transform domain data symbols bearing the modulated data with a reproduced version of the predetermined data sequence to form a correlation output signal and to recover the embedded data from the correlation output signal. The correlation processor is operable to repeat the correlation for transform domain data symbols and data symbols of the predetermined data sequence for each of a plurality of start positions in the transform domain.

Abstract: A spatial domain using image produced by a source is combined with watermark data Ri to produce a spatial domain watermarked image. The watermarked image is produced by an embedder according to equation: Ci?=Ci+?. Ri, where Ci and Ci? are wavelet transform coefficients of the image, and ? is a scaling factor. ? is chosen so that the watermark is imperceptible in the image and to resist removal of the watermark by unauthorized processing. It is desirable that a has the smallest value which achieves that. If ? is too big the watermark is perceptible in the image. If ? is too small the mark may not survive processing of the image.

Abstract: A system for facilitating copyright protection of material includes an apparatus for detecting the presence or absence of a block of data, which may have been embedded repeatedly a predetermined number of times in the material. The presence or absence of the data block is detected from data representative of versions of the data block recovered from the material. The apparatus comprises an accumulator operable to combine the value of the bit at each corresponding position within each recovered version of the data block to generate for each bit an accumulated score. A detection processor is operable to compare the value of the accumulated scores for the bits of the block with at least one threshold, and from the comparison determine a total number of detected bits of the data block. The detection processor declares the data block as being present or absent in dependence upon the total number of detected bits.

Abstract: 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.

Abstract: 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.

Abstract: An encoding apparatus operable to encode video data representing successive images, each image comprising a plurality of pixels, comprises a differential encoder arranged to encode each image as one or more predetermined image regions, each image region being encoded as a reference value and at least one differential pixel value, the differential pixel value(s) being derived in dependence on the reference value and/or other differential pixel value(s) in accordance with an order of encoding dependency; in which, for each image region, the differential encoder is operable in a first encoding mode for a first subset of the images to encode the image region using a first order of encoding dependency and in a second encoding mode for a second, different, subset of the images to encode the image region using a second, different, order of encoding dependency, and in which the first and second subsets of images are arranged with respect to one another so that, from image to image, each image region is encoded in acc

Abstract: A method of controlling copying of an information signal, comprises the steps of:

Abstract: 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 processor comprises a code word generator operable to form the code word by generating a plurality of code word coefficients, and an encoder operable to combine the code word coefficients with the material item, and an adaptation processor. The adaptation processor is operable to adapt the strength of the code word coefficients or the material item samples in accordance with a relative sensitivity of the material item samples to carry the code word coefficients. The strength of the watermark is therefore adapted in accordance with the sensitivity of the material item to carry watermark code word coefficients. As a result there is a reduced likelihood of an attacker identifying parts of the material item to which the watermark code word has been added.

Abstract: 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 code words are generated from a pseudo-random number generator initialised with a seed value. The seed value is used to identify the marked material item, from the code word produced from the seed value. The watermarking system also includes a detecting data processor operable to identify a particular marked copy of the material item by recovering a code word from the marked material item and correlating all code words in the set of code words with the recovered code word. The detecting data processing apparatus also includes a registration processor operable to associate samples of the original material item with corresponding samples of the marked material item to which corresponding code word coefficients may have been added.

Abstract: 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. A detecting data processing apparatus is operable to identify at least one of a plurality of code words present in a marked version of a material item. The detecting apparatus comprises a registration processor operable to compare the samples of the marked material item with a copy of the original material item samples. If a sample of the marked material item and the original material item differ by a comparison threshold, the registration processor replaces the compared sample of the marked material item with the corresponding sample from the original material item.

Abstract: 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 apparatus comprises a code word generator operable to provide the code word having a plurality of code word coefficients, and an encoding processor operable to combine the code word coefficients with the material. Each of the plurality of code words of the set is uniquely associated with a data word having first and second fields. Each of a set of values of the first field is represented as a first part of the code word having a first plurality of coefficients, and the second field is represented as a second part of the code word having a second plurality of coefficients.

Abstract: 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.

Abstract: A method of transferring information signals representing still images, video audio and/or other data comprises sending, the information signals to a recipient apparatus or “viewer” 10 from a server 2 via a network 12. Data indicative of whether or not further data is to be embedded in the information signals is also sent either with the signals or separately. The further data is embedded in the information signals at the viewer 10 in dependence upon the indicative data. The further data is perceptible in the information signals as to degrade them.

Abstract: A signal processor has an input for receiving an information signal representing material, for example video or audio material. The signal processor is arranged to apply to the material a modification defined by a predetermined algorithm. The modification is perceptible in the material so as to impair the material, the perceptibility of the impairment varying in a predetermined manner in the material.

Abstract: 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.

Abstract: A system for facilitating copyright protection of material includes an apparatus for detecting the presence or absence of a block of data, which may have been embedded repeatedly a predetermined number of times in the material. The presence or absence of the data block is detected from data representative of versions of the data block recovered from the material. The apparatus comprises an accumulator operable to combine the value of the bit at each corresponding position within each recovered version of the data block to generate for each bit an accumulated score. A detection processor is operable to compare the value of the accumulated scores for the bits of the block with at least one threshold, and from the comparison determine a total number of detected bits of the data block. The detection processor declares the data block as being present or absent in dependence upon the total number of detected bits.