Abstract

Forty years ago this year, Campbell & Robson outlined the hugely influential idea of 'spatial frequency channels' in visual information processing. In part 1 of this talk I consider why that 1968 Journal of Physiology paper was of special significance, and give a brief sketch of some of the later developments. In part 2, I describe our own recent work on a model of visual coding of simple spatial features that draws some of those ideas together and gives some functional insight into what 'channels' do for us in early vision.  The model is expressed in the framework of scale-space theory, using Gaussian-derivative spatial filters to represent the 'channels'.  It makes a very specific proposal, supported by psychophysical data, about the nonlinear organization of the channels that is needed to encode unambiguously the location and blur of edges in an image. Each channel has two stages that resemble simple and complex cells, respectively, in the visual cortex.

Related Research Paper

Georgeson, M. A., May, K. A., Freeman, T. C. A., & Hesse, G. S. (2007). From filters to features: Scale–space analysis of edge and blur coding in human vision. Journal of Vision, 7(13):7, 1-21

Professor Mark Georgeson

Mark Georgeson studied Mathematics and Experimental Psychology at Cambridge University (B.A. 1970), then worked on a variety of topics in spatial vision at Sussex University (D.Phil. 1975). He took up a lectureship at the University of Bristol (1976), moved on to Aston University (Birmingham, UK) as Reader in Vision Sciences (1991), then to Birmingham University as Professor of Psychology (1995). In 2001, he moved back to Aston as Professor of Vision Sciences. He has published more than 70 papers on research topics in human vision, especially on spatio-temporal filtering operations and coding processes in spatial vision, motion perception and binocular vision. He is co-author (with Bruce & Green) of the widely used textbook Visual Perception: Physiology, Psychology & Ecology (1996, 2003). He has held research grants from UK research councils (EPSRC, BBSRC), the Wolfson Foundation and the Wellcome Trust. He was chairman of the UK Applied Vision Association (2005-2008) and is active on the editorial boards of Perception (1998- ), Journal of Vision (2003- ), Vision Research (2000-2008) and is an Associate Editor of Ophthalmic & Physiological Optics (2007- ). When not writing Matlab programs, he enjoys jazz and coffee, old movies, the political writings of Noam Chomsky, and watching Italians play football.

Books from Professor Mark Georgeson