Frederick A. A. Kingdom

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There is considerable interest in how humans estimate the number of objects in a scene in the context of an extensive literature on how we estimate the density (i.e., spacing) of objects. Here, we show that our sense of number and our sense of density are intertwined. Presented with two patches, observers found it more difficult to spot differences in(More)
In natural scenes, chromatic variations, and the luminance variations that are aligned with them, mainly arise from surfaces such as flowers or painted objects. Pure or near-pure luminance variations, on the other hand, mainly arise from inhomogeneous illumination such as shadows or shading. Here, I provide evidence that knowledge of these color–luminance(More)
OBJECTIVE This article investigates the prevalence and attributes of patients with open-angle glaucoma who exhibit improvement of visual field loss in a clinical setting. DESIGN We conducted a retrospective chart review of patients in a clinical glaucoma practice. PARTICIPANTS We identified 719 glaucoma patients with at least 5 SITA strategy visual(More)
Discriminating material changes from illumination changes is a key function of early vision. Luminance cues are ambiguous in this regard, but can be disambiguated by co-incident changes in colour and texture. Thus, colour and texture are likely to be given greater prominence than luminance for object segmentation, and better segmentation should in turn(More)
Mach bands are the illusory dark and bright bars seen at the foot and knee of a luminance trapezoid. First demonstrated by Ernst Mach in the latter part of the 19th century, Mach bands are a test bed not only for models of brightness illusions but of spatial vision in general. Up until 50 years ago the dominant explanation of Mach Bands was that they were(More)
Subjects matched the brightness of test patches located within a larger surround, where the surround was made to appear either different in reflectance from neighboring regions, or of the same reflectance but viewed beneath a transparent film. In both conditions the luminance and spatial extent of the immediate surround was equivalent, thus controlling for(More)
White’s effect is a phenomenon in which grey bars replacing segments of the white phase of a square-wave grating appear darker than those replacing segments of the black phase. The direction of the brightness difference is consistent with brightness assimilation rather than with brightness contrast. We present data from two experiments which measure the(More)
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