Bede Liu, a digital signal processing pioneer, died on 7 Might. He was 91.
Liu was extensively considered one of many founders of contemporary digital signal processing, a area that applies mathematical algorithms to research, modify, and transmit alerts together with sound, pictures, and video.
The IEEE Life Fellow taught electrical engineering at Princeton for greater than 50 years. From 1994 to 1997, he chaired the college’s electrical and computer engineering department.
Liu’s analysis aided the transition from analog to digital processing of sound, pictures, and video. His work helped set up lots of the mathematical and engineering strategies that underpin trendy communications, multimedia programs, and consumer electronics.
Though little recognized exterior engineering circles, his work is embedded in applied sciences utilized by billions of individuals. The low-power digital sign processors that make cellphone calls, streaming video, and Web communications potential will be traced to analysis he carried out within the Seventies and ‘80s.
Liu acquired the 2018 IEEE Jack S. Kilby Signal Processing Medal for “sustained contributions to the evaluation and the event of low-complexity realizations of digital sign processing algorithms.”
“We stream music and video. We take photographs with our telephones, and we ship them round. We don’t even give it some thought,” IEEE Life Fellow H. Vincent Poor stated in an obituary for Liu. “But it surely’s all due to the sign processing, image processing, and video processing that’s been developed over time, in addition to different applied sciences which have grown up beside it and enabled it, like semiconductors. The event of those processing advances was precisely what Bede was a significant a part of.” Poor is a professor {of electrical} and computer engineering at Princeton.
An impactful scholar and instructor
Liu was born in Shanghai in 1934. Throughout his childhood, his household relocated to Taiwan amid the upheaval of the Chinese Civil War. His father, Henry Liu Sr., was {an electrical} engineer.
Liu earned his bachelor’s diploma in electrical engineering in 1954 from the National Taiwan University, in Taipei. After graduating, he and his household moved to the United States. Liu and his father attended the Polytechnic Institute of Brooklyn (now the New York University Tandon School of Engineering) collectively. They earned their grasp’s levels in electrical engineering in 1956. Liu continued his research on the faculty, incomes a doctoral diploma in electrical engineering 4 years later.
In 1959 he was awarded a Bell Labs fellowship and labored on the firm’s Murray Hill, N.J., location till he joined Princeton in 1962.
“Liu was a extremely impactful scholar and instructor—at all times considering forward of future wants and altering applied sciences,” stated IEEE Life Fellow Peter J. Ramadge, a Princeton professor emeritus of engineering.
Cellphones make use of a substantial quantity of digital sign processing, Liu as soon as famous. Most of the area’s advances, he added, concerned making subtle processing sensible on units with restricted computing energy—which is the problem that confronted generations of engineers designing transportable electronics.
Liu’s analysis contributions helped form each the idea and observe of digital sign processing. With Abe Peled, a former graduate scholar, he authored the 1976 textbook Digital Signal Processing: Theory, Design, and Implementation, which is a regular reference for engineers. Revealed earlier than digital sign processing had totally emerged as a definite self-discipline, it helped outline the topic for practitioners and college students all over the world.
Liu additionally revealed 250 technical papers and was granted 12 U.S. patents. His papers can be found to learn on the IEEE Xplore Digital Library.
The primary patent granted to him and Peled was in 1976 for a {hardware} design that processed bits in parallel, slightly than in sequence. The innovation drastically elevated computing effectivity for knowledge together with sound and communication alerts.
Peled says Liu “demonstrated an openness to new concepts and a willingness to problem the orthodoxy of the EE division at the moment—which leaned closely towards extra theoretical data idea.”
A mentor to well-known engineers
Liu’s affect prolonged past his personal analysis. He suggested 53 doctoral college students, lots of whom went on to distinguished careers in academia and trade, together with management positions at Google and IBM. One former scholar, pc scientist Robert Kahn, helped create the structure of the trendy Web. Kahn, an IEEE Life Fellow, acquired the 2024 IEEE Medal of Honor.
“His former college students had been very profitable,” Poor stated of Liu, “and I believe that’s a testomony to his ability as a mentor.”
“Liu was a extremely impactful scholar and instructor—at all times considering forward of future wants and altering applied sciences.”—Peter J. Ramadge
Along with a number of Ph.D. college students, Liu developed strategies of filtering and compressing digital alerts to mitigate errors and dramatically cut back the computation wanted for sign processing.
As digital sign processing moved from laboratories into business merchandise, the impression of Liu’s concepts unfold throughout industries. His analysis helped spawn the event of lower-cost and lower-power electronics and contributed to advances in cell communications, multimedia expertise, industrial automation, and biomedical imaging.
A concentrate on media integrity and copyrights
Within the 2000s, Liu turned his consideration to media integrity and copyright points.
“With the rising accessibility of digital media supply materials, the safety of possession and the prevention of unauthorized alteration has grow to be an vital concern,” he wrote in his 2002 e book, Multimedia Data Hiding. The e book, which he co-wrote together with his former doctoral scholar IEEE Fellow Min Wu, mentioned the idea, strategies, purposes, and safety of digital watermarking—hidden alerts that would determine a real copy of a track, picture or video to stop unauthorized distribution or tampering.
A Princeton group that included Liu, Wu, and one other of his doctoral college students uncovered severe vulnerabilities in watermarking applied sciences being thought-about by an trade consortium. They discovered that the standardization efforts had been immature and wouldn’t shield towards digital piracy.
“Now almost each copy of a Hollywood movie given to a critic or theater carries a novel digital forensic watermark to stop unauthorized redistribution,” stated Wu.
A drive locally
Liu, an lively IEEE volunteer, served on the IEEE Board of Directors in 1984 and 1985. He was the 1982 president of the IEEE Circuits and Systems Society.
He was a member of the U.S. National Academy of Engineering, an academician of China’s Academia Sinica, and a international member of the Chinese Academy of Sciences.
Exterior the classroom, he was acknowledged for his humility, humor, enthusiasm, and generosity. When considering of Liu, IEEE Life Fellow Kenneth Steiglitz says, cheer is the primary phrase that involves thoughts.
Liu was “at all times prepared with a optimistic comment, a fast smile or, perhaps, some tips about the precise approach to cook dinner a duck,” says Steiglitz, professor emeritus of pc science at Princeton.
Liu inspired his college students to tackle formidable, unconventional tasks, and he impressed college students and colleagues together with his adventurous spirit.
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