Peripheral vision and pattern recognition: a review - strasburger - main

Peripheral_Vision.doc
and implemented test algorithms are briefly reviewed by McKendrick (2005). Further information
can be found at the Imaging and Perimetry Society’s site (http://www.perimetry.org; for example
Thompson & Wall, 2008). Eisenbarth, MacKeben, Poggel, and Strasburger (2008) explored the
potential of double-pulse perimetry (cf. Section 3.6.3), and showed that in age-related macular
degeneration temporal thresholds are severely impaired far outside the macula, up to 20°
eccentricity.
A very different route has been taken for driving and pilot fitness assessment. An unpublished
study of ours (Strasburger, Grundler, & Burgard, 2006) demonstrated that standard perimetry
may not the best indicator for safe driving as it does not assess temporal sensitivity and
attention in the visual periphery. In the US, the Useful field of View (UFOV) test, which mixes
sensory and attentional testing, has been shown to be a good predictor of driving fitness (cf.
Ball, Owsley, Sloane, Roenker, & Bruni, 1993). In Europe, a test of peripheral temporal
sensitivity named PP in the Vienna Test System has been found particularly predictive of driving
fitness (Strasburger et al., 2006, Burgard, 2005).
3.6.6 Other functions
Many more visual functions have been studied with respect to whether and how they change
with eccentricity in the visual field. A few are listed in Table 8, together with key references for
further information.
Visual Function
Source
Perceived locus of a target Osaka (1977)
Saccadic suppression Osaka (1987)
Broca-Sulzer Effect Osaka (1982)
Suppression of vestibulo-ocular reflex Hood et al. (1984)
Suppression of melatonin Adler et al. (1992)
Table 8. Other functions studied in research on peripheral vision
4. Recognition of single characters
In the previous chapter we have reviewed visual tasks that involved unstructured or very simply
structured stimuli. Characters can be considered one step further in terms of complexity and
might thus be more representative for capturing what is special about form vision. Surprisingly,
however, it turns out that the prototypical situation of recognizing single characters at high
contrast shares many characteristics with discriminating simpler forms, and it is only at lower
contrast or with multiple characters that differences emerge. In the present chapter we look at
the recognition of individual characters. We start with characters at high contrast where we
review letter acuity and issues of recognition proper. From there we proceed to character
recognition at lower contrast, reviewing technical questions of stimulus presentation at low
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