The College of Engineering -- University of Wisconsin-MadisonAnnual Report 1998
ENGINEERINGSOLUTIONS
ELECTRICAL AND COMPUTER ENGINEERING

Big Letterssistant Professor Damon Tull is no stranger to cameras--both in front of them as a child actor in the 1970s and now as a researcher behind the scenes developing new technologies for the next generation of digital video applications. In the near future, digital television, enhanced cable and wireless services will provide unprecedented access to video data in digital format. "This impending reality will impact the way we teach, learn, communicate and do business," Tull says. Tull's research focuses on developing new image and video processing tools (algorithms and systems) that extend the capabilities of imaging systems by incorporating more processing power at the point at which images are acquired. Tull views images as a collection of objects that can be individually compressed, enhanced and Multimedia Tull cataloged. While compressing, segmenting and enhancing an image scene is done almost effortlessly by the human visual system, deriving approaches to perform these tasks by computer presents a difficult challenge. Knowledge of the human visual system and digital camera technology is combined to obtain meaningful solutions to these problems. Ultimately, efficient algorithms can be implemented in cameras to facilitate the transmission of video over the Internet and wireless networks, and improve image quality in medical, video conferencing and photography applications.

Smaller, taller micromachines show commercial promise


Strong market potential may exist for the microactuators and micromotors under development in Professor Henry Guckel's applied microelectronics laboratory. Using a technique involving deep X-ray lithography, these new devices can be produced with much greater structural heights than are currently achievable with more traditional methods. According to Guckel, the increased height allows miniaturized machines to store greater amounts of energy and produce larger forces, leading to increased functionality. In addition, the structures may be built of a variety of metals allowing the devices to be driven by magnetic forces.

Applications for these microactuators include controlling the movement of magnetic recording heads to expand the amount of information stored on a computer hard disk. The lab's actuators are able to position such a head to an accuracy of less than one-tenth of a micron--a factor of 10 improvement over current hard-drive controllers. Other applications include fiber optic switches, heads for ink-jet printers, and micro-pumps to move small amounts of fluids. Guckel's lab is working in conjunction with industry to bring these devices to market within a few years.

Making music more harmonious


Associate Professor William Sethares is finding ways to make music more harmonious. He is making a wide variety of sounds work better for both conventional and unusual musical scales. The improvement is based on the idea that the tonal quality of a sound influences listeners' perceptions of the consonance (or smoothness) and dissonance (or roughness) of notes of any two pitches (referred to as musical intervals). Sethares has developed technical definitions of "consonance" and "dissonance" that let him sculpt sounds and intervals that precisely control the amount of consonance and dissonance in musical passages.

Sethares groups sample tones into stored digital versions, creates maps of the digital tones, and programs a computer to gently adjust the partials' frequency. "You're manipulating the sound at the level of the partials in such a way as to make this dissonance as small as possible," he explains. And the changes in the harmonic structure are so subtle as to barely change the note's normal character, he says.

Sethares has also written software to "reverse engineer" tones: Instead of adjusting the partials to match a predetermined scale, it can analyze a tone and generate the most consonant-possible scale. Examples of this and other techniques appear on a compact disk that accompanies a book--titled "Tuning, Timbre, Spectrum, Scale," Springer-Verlag, 1998.

Willis J. Tompkins, Chair


Willis J. Tompkins
2134 Engineering Centers Building
1550 Engineering Drive
Madison, WI 53706

Tel: 608/262-3840
Fax: 608/262-1267
E-mail: tompkins@engr.wisc.edu
www.engr.wisc.edu/ece



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1998 Annual Report Contents