Communications and Signal Processing Seminar
Learning to detect an oddball target
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What policy should you employ if you were to locate an oddball target among many (two or more) distracters? You do not know the statistics of the observations that a 'view' of the oddball produces. Nor do you know the statistics of the observations arising from a view of a distracter. The objective is to minimise the search time, subject to keeping the probability of false detection low. Clearly, the common statistics of the distracter-generated observations should be compared, recognised as similar, and further recognised as different from those generated by the oddball target. But where should you look next, when should you stop, and when you stop, what should you decide as the oddball location?
When the observations are points of a Poisson process (as in firings of neurons), and when the probability of false detection is driven down to zero, we will discuss the best growth rate of the expected search time. We will also identify an asymptotically optimal search policy that achieves the best growth rate. Finally, we will apply our results to a particular visual search experiment studied recently by neuroscientists and will highlight how prior information affects search performance.
Rajesh Sundaresan is a Professor in the Department of Electrical Communication Engineering and an Associate Faculty in the Robert Bosch Centre for Cyber-Physical Systems at the Indian Institute of Science. His interests are in communication, computation, and control over networks. He was an associate editor of the IEEE Transactions on Information Theory for the period 2012-2015. He received the B.Tech. degree in electronics and communication from the Indian Institute of Technology Madras, the M.A. and Ph.D. degrees in electrical engineering from Princeton University in 1996 and 1999, respectively. From 1999 to 2005, he worked at Qualcomm Inc. on the design of communication algorithms for wireless modems. Since 2005, he has been with the Indian Institute of Science with brief visiting positions at Qualcomm (2007), Coordinated Sciences Laboratory of the University of Illinois at Urbana-Champaign (2012-13), and the Toulouse Mathematics Institute (2015).