Untitled Document

Fu Ming Sun, Inventor

Digital watermark technology

By Veronica Li

Veronica Li

Veronica Li

Fu Ming Sun was inspired by a friend who was doing research on Internet watermarking.

Watermarked image with hidden data looks similar to the original.

Fu Ming Sun, a 26-year-old inventor, created digital watermark technology.

It is a breakthrough in the history of watermark technology.

He is currently a part-time doctoral student of electrical and electronic engineering at Hong Kong University of Science of Technology.

He was also one of the 14 finalists of the 2001 Young Inventors Awards, which was organized by The Far Eastern Economic Review and Hewlett-Packard Asia Pacific.

"I believed it would be innovative to add digitalization into watermark technology since no one had ever successfully invented it, so I decided to try,"said Mr. Fu.

Watermark technology is the process of adding a hidden signal into a medium. A medium can convey two signals to users, a visible one and a hidden one. The hidden signal, which is normally invisible, provides additional information.

Bank notes are an example of application of this technology. The bank note is the medium which conveys a visible image to indicate monetary value for exchange between users. Its hidden image is stored in the bank note for examining the bank note's authenticity against counterfeits.

Digital watermark technology simply adds the invisible signal into digital media, such as images from the Internet.

Halftone imaging is a printing technique widely used in a laser printer. Halftone indicates a black and white image. It looks like the original grey scale image.

When one uses watermark technology in a halftone image, binary data such as ownership identity, a time stamp, a serial number or a visual logo can be hidden in the printed media for authentication and security.

The equipment needed to perform this technology is simply a computer, a printer and a scanner.

"We just need to add a program into the chip of a printer so that it can perform the required printing effect. It is not expensive and is actually easy to work with,"said Mr. Fu.

A company can employ watermark technology to store secret information in a printed document, such as a staff photo with 30,000 bits of data.

The photo should first be stored in 30,000 points. Data are then inserted into the photo by computer. The data can be made transparent in the photo with a process called error compensation.
The photo which contains watermarked data will look very similar to the original one. Although there will be a difference between two photos, one cannot see it with the naked eye.

Watermark technology can be used for copyright, authentication and data hiding. Different digital watermark techniques are used for different purposes.

For authentication, Mr. Fu suggested the application of watermark technology in making passports.
"Photos on passports are for verification. However, once the photo is scrubbed out, it can be used by another person as a sham passport," he said.

By applying digital watermark technology, data like the passport holder's name and identity card number may be inserted into the photo.

If someone removes the original photo and replaces it with another, he will not be successful because of the hidden data.

"When the photo is checked and it is discovered that no personal information is inserted into the photo, the authorities will conclude there must be something wrong with the passport," he explained.

Digital watermark technology can thus avoid replacing fake photo or modifications of data in passports.

Another potential application of digital watermark technology is in bank cheques for security.
Every cheque has a different serial number. The serial number is directly printed on the cheque, which is easy for people to imitate.

With the help of digital watermark technology, a bank logo and an additional serial number can be stored in the cheques.

It is not necessary to put a bank logo on a cheque. Inserting important data into the logo, however, can decrease the ease of duplication.

Asked whether digital watermark technology can replace the current watermark technology for bank notes, Mr. Fu gave a definite answer.

"It is impossible. No method is perfect.

"This technology is better if used together with other methods, such as encryption, for better security," he said.

To encrypt the data, it is firstly codified before inserting into the photo. A bunch of numbers will appear if someone tries to take out the hidden data. Decryption is needed if someone wants to read the information. This provides a double protection.

In addition to using watermark technology for verifying purposes, it also applies in printing greeting cards.

"A boy can present a card with a digital watermark to his girlfriend to show his love. He needs to prepare two cards. When the two cards combine, it portrays a full picture, like a boy kissing a girl," said Mr. Fu.

Any innovative technology will encounter some problems. The watermark technology is no exception.

Mr. Fu's major concern is the maintenance of the visual quality of the picture when adding data into it.

"There is a tradeoff between data capacity and the visual quality of the photos. If we want to add large amounts of data into the photo, its data may affect the quality of the photo.

"This is an issue which I need to work on more now," he said.

Another concern is the problem of security.

According to Mr. Fu, it is crucial to restrict the details of secret information to data owner and data receiver only.

"In this way, it can provide protection from tamper detection," he said.

Since digital watermark technology is a minor topic, Mr. Fu encountered dilemmas during his research.

"The most difficult part is having few people to share my research experience. Not many people have tried to work on this subject before.

"Sometimes I wondered if I would be able to finish it all by myself. I had once thought of giving up," he recalled.

Fortunately, his passions on this project exceeded his worries.

His invention of the digital watermark technology succeeded when the university supported it.
In June 2000, Mr. Fu was chosen to represent the university by presenting the technology in an international conference.

"Three years of hard work are being recognized now,” said Mr. Fu with a satisfied smile.

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Veronica Li	Veronica Li

Fu Ming Sun was inspired by a friend who was doing research on Internet watermarking.	Watermarked image with hidden data looks similar to the original.
Fu Ming Sun, a 26-year-old inventor, created digital watermark technology. It is a breakthrough in the history of watermark technology. He is currently a part-time doctoral student of electrical and electronic engineering at Hong Kong University of Science of Technology. He was also one of the 14 finalists of the 2001 Young Inventors Awards, which was organized by The Far Eastern Economic Review and Hewlett-Packard Asia Pacific. "I believed it would be innovative to add digitalization into watermark technology since no one had ever successfully invented it, so I decided to try,"said Mr. Fu. Watermark technology is the process of adding a hidden signal into a medium. A medium can convey two signals to users, a visible one and a hidden one. The hidden signal, which is normally invisible, provides additional information. Bank notes are an example of application of this technology. The bank note is the medium which conveys a visible image to indicate monetary value for exchange between users. Its hidden image is stored in the bank note for examining the bank note's authenticity against counterfeits. Digital watermark technology simply adds the invisible signal into digital media, such as images from the Internet. Halftone imaging is a printing technique widely used in a laser printer. Halftone indicates a black and white image. It looks like the original grey scale image. When one uses watermark technology in a halftone image, binary data such as ownership identity, a time stamp, a serial number or a visual logo can be hidden in the printed media for authentication and security. The equipment needed to perform this technology is simply a computer, a printer and a scanner. "We just need to add a program into the chip of a printer so that it can perform the required printing effect. It is not expensive and is actually easy to work with,"said Mr. Fu. A company can employ watermark technology to store secret information in a printed document, such as a staff photo with 30,000 bits of data. The photo should first be stored in 30,000 points. Data are then inserted into the photo by computer. The data can be made transparent in the photo with a process called error compensation. The photo which contains watermarked data will look very similar to the original one. Although there will be a difference between two photos, one cannot see it with the naked eye. Watermark technology can be used for copyright, authentication and data hiding. Different digital watermark techniques are used for different purposes. For authentication, Mr. Fu suggested the application of watermark technology in making passports. "Photos on passports are for verification. However, once the photo is scrubbed out, it can be used by another person as a sham passport," he said. By applying digital watermark technology, data like the passport holder's name and identity card number may be inserted into the photo. If someone removes the original photo and replaces it with another, he will not be successful because of the hidden data. "When the photo is checked and it is discovered that no personal information is inserted into the photo, the authorities will conclude there must be something wrong with the passport," he explained. Digital watermark technology can thus avoid replacing fake photo or modifications of data in passports. Another potential application of digital watermark technology is in bank cheques for security. Every cheque has a different serial number. The serial number is directly printed on the cheque, which is easy for people to imitate. With the help of digital watermark technology, a bank logo and an additional serial number can be stored in the cheques. It is not necessary to put a bank logo on a cheque. Inserting important data into the logo, however, can decrease the ease of duplication. Asked whether digital watermark technology can replace the current watermark technology for bank notes, Mr. Fu gave a definite answer. "It is impossible. No method is perfect. "This technology is better if used together with other methods, such as encryption, for better security," he said. To encrypt the data, it is firstly codified before inserting into the photo. A bunch of numbers will appear if someone tries to take out the hidden data. Decryption is needed if someone wants to read the information. This provides a double protection. In addition to using watermark technology for verifying purposes, it also applies in printing greeting cards. "A boy can present a card with a digital watermark to his girlfriend to show his love. He needs to prepare two cards. When the two cards combine, it portrays a full picture, like a boy kissing a girl," said Mr. Fu. Any innovative technology will encounter some problems. The watermark technology is no exception. Mr. Fu's major concern is the maintenance of the visual quality of the picture when adding data into it. "There is a tradeoff between data capacity and the visual quality of the photos. If we want to add large amounts of data into the photo, its data may affect the quality of the photo. "This is an issue which I need to work on more now," he said. Another concern is the problem of security. According to Mr. Fu, it is crucial to restrict the details of secret information to data owner and data receiver only. "In this way, it can provide protection from tamper detection," he said. Since digital watermark technology is a minor topic, Mr. Fu encountered dilemmas during his research. "The most difficult part is having few people to share my research experience. Not many people have tried to work on this subject before. "Sometimes I wondered if I would be able to finish it all by myself. I had once thought of giving up," he recalled. Fortunately, his passions on this project exceeded his worries. His invention of the digital watermark technology succeeded when the university supported it. In June 2000, Mr. Fu was chosen to represent the university by presenting the technology in an international conference. "Three years of hard work are being recognized now,” said Mr. Fu with a satisfied smile.