| 摘要 |
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. The present invention provides a facility for generating watermark code words having a hierarchy of values. By providing watermark code words having first and second parts, a data word with first and second fields can be uniquely identified. The first and second fields can be assigned to different associated parameters such as for example address parameters. The first field could therefore identify the country of distribution of the material, whereas the second field could identify a particular distribution outlet within the country. A watermarking system can be formed, which 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.
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