ColloquiaAlon Fishbach, Johns Hopkins University - March 13

[Margery Ishmael]

CS TALK ANNOUNCEMENT

Date:  Wednesday, March 13
Time:	2:30 p.m.
Place: Ryerson 251

Speaker: Alon Fishbach, Johns Hopkins University, School of Medicine

Title: "On the importance of auditory edges to biological & artificial 
auditory systems"

Abstract: One of the important challenges faced by any sensory system is 
the segmentation of a complex mixture of stimuli into distinct entities 
that correspond to different objects and events in the real world. 
Heuristically, it is reasonable for any sensory system to consider 
discontinuities in the input as possible boundaries between adjacent 
objects or events. The primary segmentation of visual scenes is often 
presumed to be based on edges, which in biological systems are detected by 
neurons that are sensitive to moving oriented edges.

In contrast with our relatively good understanding of primary visual scene 
analysis, the way in which the auditory system decomposes complex auditory 
scenes is substantially less clear. Can the auditory system utilize 
auditory "edges" or discontinuities in similar ways to those used by the 
visual system? Can artificial systems use auditory edges for the analysis 
of complex auditory scenes? In my talk I will present modeling work and a 
variety of psychophysical and physiological evidence that support the 
hypothesis that biological as well as artificial systems can successfully 
utilize auditory edges for the segmentation of auditory scenes.

A novel method for the classification of auditory neurons to edge-sensitive 
vs. level-sensitive neurons will be described and the application of this 
classification for the prediction of neural responses to speech stimuli 
will be discussed.

In addition, I will present a neural model for the detection of amplitude 
and frequency edges; its underlying principles are similar to those of 
classical visual edge detection models. The model reproduces many 
physiological and psycho acoustical phenomena, the later mainly related to 
auditory scene analysis. Moreover, by characterizing primary auditory 
cortical (AI) units using the model parameters instead of the 
response-related parameters we are able to uncover topographical order. 
These results suggest a possible ordered organization of a rotateable 
auditory edge detector in the mammalian AI.

Finally, the applicability of auditory edges for the artificial 
segmentation of complex auditory scenes will be discussed.

Bio: Alon Fishbach is a Post Doctoral Fellow at the Department of 
Biomedical Engineering, Johns Hopkins University.  He received his PhD in 
Computer Science at Tel Aviv University in 2000.

Host: Yali Amit

*The talk will be followed by refreshments in Ryerson 255*
Persons with disabilities who may need assistance should call 773.834.8977


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Margery Ishmael
Secretary to the Chairman, Department of Computer Science
The University of Chicago
1100 E. 58th Street, Chicago, IL. 60637-1581
tel. 773.834.8977  fax. 773.702.8487
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