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Young Lim Lee, Geoffrey Bingham; Large Perspective Changes (>45°) Allow Metric Shape Perception Used to Recognize Quantitatively Different Objects. Journal of Vision 2010;10(7):1002. doi: 10.1167/10.7.1002.
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© ARVO (1962-2015); The Authors (2016-present)
Background. Previous object recognition studies have shown that observers could not recognize objects using quantitative (metric) properties. The finding of a relative inability to detect the metric differences is consistent with numerous previous perception studies in which observers are unable to perceive metric 3D shape accurately. However, Bingham & Lind (2008) found large perspective changes (≧45°) allowed accurate metric shape perception. We now investigated whether such information can yield the ability to detect quantitative properties and use them to recognize objects.
Methods. 10 Ss participated in a small rotation (20°) condition and 10 Ss participated in a large rotation (70°) condition. 24 octagonal objects were used. There were 4 qualitatively different objects and each object had 5 quantitatively different variations. Every observer performed three sessions in the same order, namely 2D quantitative difference, 3D quantitative difference and 3D qualitative difference tasks. Observers viewed computer generated displays of objects with stereo and structure-from-motion information and performed a same-different task. Judgments were to be as accurate and quick as possible.
Results. When information from large perspective changes was available, the ability to recognize quantitatively different objects was comparable to that for qualitatively different objects both in respect to accuracy of judgments and reaction times.
Conclusions. The two visual systems theory suggests that the ventral system which is responsible for object recognition deals with and requires only qualitative properties. In contrast, our results showed that metric properties also can be used to recognize objects if information from large perspective changes was available. Thus, we challenged the idea that the ventral system only uses qualitative properties to perform object recognition. We suggested that use of metric shape perception is not determined by anatomically distinct visual systems, but instead it is a function of information.
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