Psychophysics of Natural Images

Tom Troscianko

(Bristol)

The paradox of vision science is that it appears easy to learn much about very simple image viewing situations, or else little about the perception of more complex scenes. Since we are interested in the perception of natural images, we are adapting normal psychophysical methods to study such scenes. We show that there is an optimisation to the properties of natural scene statistics - in particular, such optimisation applies iw we consider a task which needs a particular visual subsystem. To this end, we have been studying the properties of fruit and leaves eaten by primates in an African rainforest and finding clear evidence for optimality of coding of such stimuli. We have also used a simple approach to deal with more complex, dynamic, stimulus sequences in which the task is to predict whether violent human behaviour will occur. It may be that the primitives for such tasks can also be defined as simple, low-level operators. There may therefore be a "middle way" through the paradox: make the images complex, but keep the models simple.
Tuesday 10th December 2002, 14:00
Robert Recorde Room
Department of Computer Science