Electrical Engineering and Computer Science

Prof. Andy Yagle Retires After a 32-Year Career in Signal and Image Processing

Andy Yagle 1986
Andy Yagle

Prof. Andy Yagle will retire in May after 32 years at the University of Michigan distinguished by his dedication to teaching as well as contributions to research in the area of signal and image processing. A nearly lifelong Ann Arbor resident, Andy is as Maize and Blue as they come.

He was born in the university hospital and raised by Michigan alumni parents. His father was a Michigan engineering faculty member and his mother was a nurse at U-M Hospital. He himself holds two U-M degrees (a bachelor’s in engineering science and electrical engineering in 1977 and 1978, respectively), and both of his brothers also are Michigan alums. Aside from his years of grad school at MIT, Andy’s whole life has been spent on campus, and his professional life was here in the EECS Department..

Even though he had a great time in Boston, he kept his Ann Arbor residency. "I didn’t know I was going to come back," he said, "but I’m an Ann Arborite until proven otherwise."

When Andy started teaching in 1985 after receiving his PhD from MIT, his father was a faculty member in the Department of Naval and Marine Engineering. Their careers overlapped by nine years, when Prof. Raymond Yagle retired in 1994.

“When I first came here, we got each other’s mail by mistake,” Andy says.

Andy considers his Dad and two faculty he worked with as a teaching assistant (TA) at MIT to be major influences on his career. The TA job is where Andy learned many of his tricks for good teaching.

"Make it fun to come to class, show them what this stuff is for, crack a lot of jokes,” he says. “I was pretty good at teaching and did a lot of it – that’s why it took me so long to graduate.”

Andy’s research in signal processing focused on problems in inverse scattering, iterative algorithms in medical imaging, fast algorithms for digital signal processing, sparse imaging, and phase retrieval. He formulated a "layer stripping approach" in 1988, which became central to the theory of inverse problems. His research, because it was theoretical, was applicable to a wide range of fields, including geophysics, acoustics, cardiology, and magnetic resonance imaging (MRI).

One of his research projects was to analyze strategies for detecting and classifying landmines, including ground-penetrating radar, statistical detection, and blind deconvolution algorithms. This was a DARPA-funded Multi-University Research Initiative (MURI) focused on sequential adaptive multi-modality target detection and classification.

His research earned him an NSF Presidential Young Investigator Award and an Office of Naval Research Young Investigator Award. He later received the College of Engineering (CoE) Class of 1938E Award for outstanding contributions to research as well as teaching.

He graduated 24 doctoral students throughout his career.

Andy received a number of other awards specifically focused on teaching, including a CoE Teaching Excellence Award, and an Eta Kappa Nu Professor of the Year award, which is voted on by the students themselves. It is no surprise that Andy consistently received extremely high scores for his undergraduate teaching.

Engineering Signals and Systems Yagle Ulaby

In recent years, he turned his attention to co-authoring the textbook, Engineering Signals and Systems, with Prof. Fawwaz Ulaby. Although it has only been in print since 2013, it has already been adopted by nearly 40 universities, including Cornell, Illinois, and Texas. The book, written for an introductory signals and sytems course, focuses on applications for signal processing, whereas existing textbooks mainly focused on the math alone.

“Students don’t want to learn math,” he says. “They want to learn what this stuff is for.”

The book is in its second edition after the addition of two chapters, new concepts threaded throughout the book, and additional problem sets.

His lifelong dedication to the education of students was recognized by the College of Engineering Service Excellence Award in 2013. In his role as Chief Program Advisor for the EE program, he wrote an extensive handbook for use by both the students and the advisors. He also devised a system for faculty to avoid midterm conflicts. He provided valuable input on the CoE Curriculum Committee, the EE curriculum committee, and the CoE Admissions Committee, and served as ABET coordinator for the EE program for two different reviews.

Many students have praised the personal mentorship they received from Andy, especially those who needed a boost to make it through the program. In the words of his colleague, Prof. Stéphane Lafortune, "Andy's contributions to service, and to service-related teaching activities, have made Michigan a better place for our undergraduate students. We should all be grateful to him for that."

Fawwaz Ulaby has fond recollections of his time working with Andy on their textbook, and as colleagues throughout their long careers:

Of the many academic colleagues I have worked with over the years, none are as steeped in their mathematics, precise and insightful in their subject-matter presentations, and simultaneously humble and kind as my dear friend Andy Yagle. Andy and I wrote a textbook together entitled Engineering Signals and Systems, which took only a little over a year to write, thanks to Andy’s clear vision and unwavering focus. Working with Andy has led to more than a partnership: I regard Andy as my younger brother and a true friend.

Retirement doesn’t signal the end of Andy’s efforts. His textbook with Ulaby “never stops” – he maintains a solutions and examples companion website for the book, and will continue to update it going forward. In addition, he and Ulaby plan to write a second textbook, this time on image processing.

Andy’s career spanned a time in which signal processing has expanded to tackle new challenges such as big data, machine learning, and self-driving cars. He's seen significant changes since his years as an undergraduate student when he was using punch cards. Throughout it all, he has kept his focus on making his material as applicable to the real world and as relatable to his students as he could.

Andy chose to major in electrical engineering because he wanted to do more than just math, which he loved. And that's what he's seen in his students. “Most students don’t want to be mathematicians, they want to be engineers,” he says. “You teach for the students, not for yourself.”

Posted April 27, 2017