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Media Release

26 May 2004

UniSA researchers add digital watermarks to protect copyright

Researchers at the University of South Australia have developed intelligent watermarking techniques that give owners copyright protection on images and data used in Internet and other applications.

Because of huge advances in technologies that make it difficult to control the copying and manipulation of photographs and other documents, finding intelligent ways to identify the true source of information are urgently needed, according to Professor Lakhmi Jain, Director of UniSA’s Knowledge-Based Intelligent Engineering Systems Centre.

“By embedding a digital watermark such as a logo within an original image or other documents and attaching a user key, original material can be easily identified,” Professor Jain said.

“Only the user with the correct key, similar to the right pin number, can extract the hidden watermark to reveal and use the original image or document, and verify that correct material has been sent.

“UniSA’s intelligent watermarking technology is world class research that no one else can copy. I don’t believe that anybody will be able to unlock the secret code to reveal the user key because the owner’s identity has been securely embedded using intelligent algorithms,” Professor Jain said.

The research has many practical applications and Professor Jain and his team including visiting Professor Peter Jeng-Shyang Pan from National Kaohsiung University of Applied Sciences in Taiwan, and PhD student, Feng-Hsing Wang, are ready to demonstrate that their system works.

“Digital watermarking has enormous potential for passport control. The Department of Foreign Affairs and Trade could have watermarks hidden in passports that could be extracted to find forgeries. For passport identification, images of fingerprints, the iris of an eye or even voice speech could be embedded as watermarks within passports,” Professor Pan said.

“Companies with videotapes, CDs or DVDs, for which they own the copyright, could embed their logo or some other identification in the original media. If an unauthorised person is in possession of these items, affected companies could use their identification key to demonstrate that the tapes or disks were stolen or copied illegally.

“Tenders or other important documents could have watermarks embedded before being forwarded by email, enabling receivers with access to the correct user keys to confirm that the right documents have been received,” Professor Pan said.

“The same technology could be used by art galleries to identify original artwork and detect forgeries. Original artworks could also have watermarks with web addresses embedded that give detailed information about each artwork when accessed by a mobile phone user with the correct identification key,” Professor Pan said.

If there is a problem with the quality of transmission over the Internet, which leaves images distorted, it is still possible even under the worst conditions to identify an original image, according to Feng-Hsing Wang. “With access to the correct user key, we can extract the watermark, which may also show some distortion.

“Even if people only copy and use part of a picture, we can still extract our embedded symbol from any part of the picture to prove its origin because we’ve hidden information in the whole picture,” Wang said.

“We can embed a very high capacity of information into an original image or document and, depending on the level of security required, users of our technology can have multiple keys or watermarks, with logos or other identification hidden within logos,” Professor Jain said.

“We can add three or more watermarks, each with separate user keys, for added security and for limiting access to sections of information. One large report can be watermarked to give access to the full report with one user key, while other recipients may be issued with a second class key that enables them to extract watermarks revealing only relevant sections of the report.

“The intelligent watermarking techniques that we have developed will have many valuable applications in commerce and important solutions for the problems that the world is facing,” Professor Jain said.

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