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5.6 Effects of orientation and learning
5.7 Form fields
5.8 Profile recognition
5.9 Dynamic effects
5 .l0 Discussion
References
6. MODELLING OF VISION. 1: A HISTORICAL SURVEY
Having discussed the experimentally evaluated threshold performance of human
vision in considerable depth it is time to consider how to predict human visual
performance. Now, as was seen in Chapter 2, the human visual system is very
complex. Hence at first sight it seems unlikely that any simple modelling will
allow predictions of performance over other than a very restricted range of
conditions. This complexity has not deterred many researchers from attempting
to provide reliable modelling of at least some facets of vision. Such modelling
has, until recently, inevitably had to be to a large extent empirical, since it is
only recently that some of the physical parameters associated with the eye (such
as eye movements and the optical spread function of the refraction optics) have
been successfully determined. This chapter is devoted to a historical survey of
the progressive development of empirical and semi-empirical models of parts of
the spectrum of visual performance and a short description of the more
complete of these models which are in common use today.
6.1 Simple laws governing limited regions of visual performance
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