Selective Visual Attention: Computational Models and Applications

2.4 Binding Theory Based on Oscillatory Synchrony

As discussed in Section 2.1.1, search for an object with different characteristics (form, colour, orientation and motion) in the visual field often involves different visual areas in the brain cortex, from the retina, LGN, V1, to dorsal and ventral pathways, up to the high level cortex areas. How to bind together these activities distributed in different areas of the HVS to represent a target or an object is a fundamental step in visual pattern recognition. This is the so-called binding problem, that is the process responsible for linking distributed activities.

From the point of view of psychophysics and psychological science, as mentioned by Treisman group's FIT and Wolfe group's GS models, feature binding occurs due to spatial attention that provides the glue for the independently registered features of an object. In these models, integrating related features is carried out in the attention or pre-attention stage. The problem is that the relationships among features must be available for further processing since there are many possible combinations for the continuous scenes input from the retina. The question is how to separate one set of features from another. For example, a boy wearing a red cap is playing with a red ball in a scene. The locations of the two targets with similar form and the colour (the boy's head with red cap and the red ball) are very close; sometimes they are even overlapped or occluded by one another, but ...