The Johns Hopkins Gazette: January 3, 2000
January 3, 2000
VOL. 29, NO. 16


Transformation Tool Helps Move Images

Process saves battery power in laptops, digital cameras and hand-held computers

By Phil Sneiderman

Johns Hopkins Gazette Online Edition

To send images and video from one place to another, computers now rely on compression--a method of squeezing large amounts of digital information into smaller packets that can be moved swiftly along an electronic highway. Before compression can take place effectively, the data collected from the sensors of a digital camera or a scanner must first undergo a mathematical transformation.

A Johns Hopkins University engineer has invented a new digital transformation method that promises to speed up the transmission of digital multimedia while using far less power. The increased speed could make it easier to conduct high-quality video-conferencing in real time, the inventor says. At the same time, the reduced demand for power will make it more economical to process images on battery-operated devices, including laptops, hand-held computers and digital cameras, the researcher suggests.

The mathematical breakthrough, called the BinDCT, allows a computer to transform and restore digital data at least three times faster than the method that is now used commonly throughout the world. This "mathematical transform" was developed by Trac D. Tran, an assistant professor in the Whiting School's Department of Electrical and Computer Engineering. Tran unveiled his invention at the 33rd Annual Conference on Information and Science Systems, held recently in Baltimore, and at the 1999 International Conference on Image Processing in Kobe, Japan. He has prepared follow-up articles for electrical engineering journals and has also applied for a U.S. patent covering the new transform.

Trac Tran

Tran says the BinDCT could significantly improve the data processing capability in compact electronic devices that rely on small chips and limited power supplies. This would allow low-cost digital cameras, palm-size computers and perhaps even cellular phones to keep up with the multimedia communication rate, he says. Tran's breakthrough involves a change in the mathematical process used to prepare images before they are compressed and transmitted. The current method involves multiplication and thus requires a lot of computational horsepower. The BinDCT, however, requires no multiplication at all. It uses only binary shift and addition operations, so the process can be completed with a much smaller, hence less-power-hungry chip.

"This transform is fast and binary-friendly. The microchip can be very small with low power consumption. Most importantly, it maintains the same level of image quality," Tran says. "We think it would be ideal for wireless communication devices, palmtops and anything else that does not have the extensive computational power that you would normally find in a high-end workstation."

During breaks from his high-tech computing research, Tran devotes time to an unrelated Web page project that pays tribute to the literature and culture of his homeland, Vietnam. In 1986, he and his younger brother left Vietnam as refugees. The two teenagers first lived with relatives in San Jose, Calif. After attending Andrew Hill High School in San Jose for two years, Tran gained admission to MIT, where he received his bachelor's and master's degrees in electrical engineering in 1993 and 1994, respectively. Tran earned his doctorate in the same field from the University of Wisconsin-Madison, just before he joined the Johns Hopkins faculty in July 1998.

Although Tran is now a U.S. citizen, he maintains close ties to his native land by presenting Vietnamese literature, history, music and artwork on his Web site, located at The site is well-known among Vietnamese immigrants in the United States and is often visited by Web surfers in Vietnam itself. "This Web site currently presents only a humble sample of 4,000 years of Vietnamese civilization. I envision the site to become a complete online interactive encyclopedia in the future with rich multimedia contents that can serve as a great research, educational, as well as entertainment tool," he says. "Besides, there is a new generation here that has not been exposed to Vietnamese culture and literature. The project is still in its infancy. I just wish I had more time."