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Flip Phillips, James T Todd; Local and global coherence in two and three dimensional textures. Journal of Vision 2003;3(9):610. doi: 10.1167/3.9.610.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose— What can the perception of scale and coherence of texture features tell us about the nature of our visual representation of shape? A trivial gedankenexperiment shows that the scale of features in 2- & 3-D textures has a direct effect on the ability of an observer to make ‘same/different’ judgments. Fields of uniformly distributed, high spatial frequency features are more difficult to match than their lower frequency cousins. However, in cases where the distribution of point features is not uniform, ‘meta-features’ may cohere in the form of clusters or linear structures that alter the scale at which matching is possible.
What is the nature of this scale/structure relationship?
Methods— In a series of experiments, fields of uniformly distributed noise were presented in a same/different matching task. Spatial frequency of the noise varied in concert with different structuring and de-structuring operations. These included introduction of linear and area structures through filtering and the modification of phase information.
Results— Spatial frequency thresholds for the noise-only discrimination tasks were on the range of 1.5–2.5 degrees of visual angle. Linear structuring of the noise yielded performance consistent with the scale of the introduced structuring. Disturbing the phase in the structured noise again degraded performance consistent with the unstructured conditions.
Conclusions— Our results show that structuring the point features of uniform noise creates emergent features that are more readily used as ‘landmarks’ for a matching task. At least part of the structuring takes place in the texture's phase-space because disturbing phase degrades performance back to unstructured levels.
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