Cochrea Modeling Retrospective

Richard F. Lyon
Google

Monday, October 8, 2007 at 1:00PM

54-134 Engineering IV Building
Refreshments Served

Abstract: There is a long history of cochlea modeling that people need to be aware of, to help design, optimize, and evaluate neuromorphic hearing systems. In particular, it's important to understand: the notions of time-frequency and time-scale separation and the classes of filters that these notions imply; the large-scale AGC and "essential" nonlinearities that compress the wide dynamic range of sound into a small representation range; the indirect relationship of transfer functions to tuning curves; the relative properties of cascade and parallel filterbanks; the need for higher-order poles to get realistic transfer functions; why zeros are needed to keep the delay realistic; and why and how to capture temporal structure for subsequent processing. We review these topics and some early contributions to this field.

Biography: Dick Lyon is a research scientist at Google, where he is returning to his roots in biomorphic hearing systems, a field that he helped develop 30 years ago. His recent foray into digital cameras and sensors, as chief scientist for Foveon, provided some distance and perspective on this field. Stints at JPL, Bell Labs, Stanford Telecomm, Xerox, Schlumberger, Apple, and Caltech provided the varied background for these explorations. Dick invented the optical mouse while at Xerox. His other pioneering work include: designing early Global Positioning System test transmitters, inventing the first single-chip ethernet device, early work on static CMOS memory, and designing most efficient large CMOS address decoder. His cochlear model is used as the basis of much auditory research today, and he invented optical and integrated-circuit techniques that allow digital cameras to be denser and more accurate. He was elected IEEE Fellow in 2003 "for contributions to VLSI signal processing, models of hearing, handwriting recognition, and electronic color photography", and was awarded the "Progress Medal" of the Royal Photographic Society, along with Carver Mead and Richard Merrill, for the development of the Foveon X3 sensor. Dick is one of the persons featured in George Gilder's book The Silicon Eye.