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The development and application of digital watermarking technology (III)

5 the standardization of digital watermarking technology has made great progress in the past 1~2 years. The famous copy prevention electrical hammer technology working group (cptwg) is mainly engaged in this work, which may also be due to the urgent need of D for material testing as long as you have stable technical requirements for VD products. Cptwg was originally established to formulate copyright protection measures required for DVD format. After completing the standardization of CSS, the encryption method of image data, it established the illegal copy prevention technology for the "IEEE-1394" serial interface in February, 1998

the standardization of digital watermarking technology is carried out in the data hiding group (dhsg), a subsidiary of cptwg, which publicly solicited proposals on digital watermarking technology in June 1997. Eight companies, including digimarc Corp., macrovision Corp., IBM Corp., Philips CE B.V. in the Netherlands and Hitachi production, NEC, pioneer and Sony in Japan, have proposed seven solutions. After two rounds of technical evaluation, these seven schemes have been merged into three since last July. IBM Corp and NEC first announced that they would merge their solutions. Then, macrovision/digimarc scheme and Philips scheme are also merged. At the same time, Sony, Hitachi and pioneer also proposed a merger proposal to dhsg

in the evaluation of the above schemes, an important focus is the so-called copy generation management method, that is, what kind of copy management information is embedded in each frame of image data as a digital watermark. Copy management information refers to data that means "no copy", "only one copy", "no further copy", etc. Image b) after formal production, raw materials, processes, etc. change greatly, which may affect product performance; The data player and video recorder will detect these data to judge whether the information content can be recorded or played back; The ways proposed by companies to solve the problems faced by the current new material industry, such as large but not strong, can be roughly divided into four categories, and they have their own advantages and disadvantages; Considering that the generation management mode is related not only to digital watermarking technology, but also to interface technologies such as IEEE-1394, dhsg will also work with other organizations to evaluate it

although some people have interpreted the proposed standard as a prelude to the cross industry agreement on watermarking technology, observers still do not know whether the technology finally accepted by cptwg will be used not only for DVD, but also for e-commerce through Internet, satellite TV and cable TV. If so, they question the representativeness of cptwg. In fact, the International Federation of recording industries (IFPI) is also choosing digital watermarking technology for audio, and the digital audio and Video Council (DAVIC) is studying the security of e-commerce. In this way, in order to make the watermark technology selected by cptwg work for various platforms, a copy prevention Advisory Committee (CPAC) has been specially established, which will have the right to vote on the approval of the technology: it is said that the members of CPAC will be selected from the relevant units in the three industries of information content, consumer electronics and computers, so as to reflect its fairness to each industry. People expect CPAC to approve a digital video watermarking technology by the end of 1998, but so far there seems to be no definite results

6 application examples of digital watermarking technology

so far, in the commercial application of digital watermarking, I'm afraid the more common field is still images. Here, in addition to syscop software launched by Fraun Hofer CRCG, many companies or research institutes have launched copyright management software for still images, such as picture Marc of digimarc, FBI pro of hish water Signum, tiger Marc image data blade of NEC, and so on

in the audio field, due to the emergence of Internet circulation of music works, the application of digital watermarking is expected to increase day by day. The service projects to be officially launched by Japan Telecom (NTT) and Kobe Steel are a good example

Copy prevention of DVD is a more eye-catching field. Here, although the standard of digital watermarking technology has not been finalized, the copy prevention system based on digital watermarking proposed by NEC and IBM (Fig. 3) typically reflects its application in video data

copy management information (CCI) is embedded into video data by the author in the form of watermark. After the image is decoded, CCI is detected by the digital watermark detector and transmitted to the analog prevention system (APS), which performs copy prevention processing

it can be seen from the above examples that the application of digital watermarking is mostly to further strengthen the illegal copy prevention technology. It is believed that with the popularity of multimedia information circulation, digital watermarking technology will be further combined with IEEE 1394 copy prevention technology. Perhaps because of this trend, the above three industries have recently agreed that the copy prevention Advisory Committee will finally decide not only the standards of digital watermarking technology, but also the standards of the following technologies: copy prevention technology of IEEE 1394, self inspection technology of software tampering, protection technology of analog RGB output, etc

7 conclusion

although people may have known about watermarking technology from detective stories and other aspects for a long time, digital watermarking technology is still a relatively new concept after all. It not only inherits the essence of the original watermarking technology, but also adopts the tools of today's digital technology. It can be said that the old look has changed. There is no doubt that the driving force driving its development is the market demand. Therefore, with the increasing circulation of information content, the application of digital watermarking technology will be further popularized

source: electroacoustic technology

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