Topic
Foveal
About: Foveal is a research topic. Over the lifetime, 2652 publications have been published within this topic receiving 94120 citations.
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TL;DR: The results suggest that statistical spatio-temporal stimulus regularities are effectively integrated by human visual cortex over a range of spatial and temporal positions, thereby systematically affecting perception.
33 citations
TL;DR: It is concluded that integration of parametric visual form information occurs across saccades, but that it relies on a quickly decaying and maskable visual memory.
33 citations
Journal Article•
TL;DR: Changes in temporal tuning (both psychophysical and electroretinographic) were found only within visual field scotomas, whereas changes of the log sensitivity parameter were found also in the relatively preserved foveas of this group of patients with early stage RP.
Abstract: PURPOSE. The relation between early changes in the photopic flicker electroretinogram (ERG) and photopic psychophysical changes in retinitis pigmentosa (RP) is poorly understood. Here, abnormalities in foveal and extrafoveal temporal contrast sensitivity functions (TCSFs) were studied in a group of carefully selected patients with RP who had relatively preserved macular function. The psychophysical results were compared with changes in the timing of the multifocal ERG. METHODS. Subjects were patients with RP who had acuity $20/32 and no visual field defects within 6° from the fovea. Maxwellian-view and direct-view optical systems were used to obtain foveal and extrafoveal TCSFs under a range of test conditions, including high retinal illuminances that yielded temporal contrast sensitivity independent of mean retinal illuminance. TCSFs were described using log sensitivity and corner frequency parameters. RESULTS. Foveal TCSFs in these patients showed overall reductions in sensitivity but no frequencydependent defects. Also, no macular defects were found in the timing of the multifocal ERG. TCSFs from extrafoveal locations in moderate field defects, obtained at retinal illuminances that were sufficient to render flicker sensitivity independent of effective mean luminance, showed reductions in overall sensitivity as well as changes in temporal tuning. The multifocal ERGs from these extrafoveal locations showed signs of temporal slowing. CONCLUSIONS. Changes in temporal tuning (both psychophysical and electroretinographic) were found only within visual field scotomas, whereas changes of the log sensitivity parameter were found also in the relatively preserved foveas of this group of patients with early stage RP. (Invest Ophthalmol Vis Sci. 1999;40:2932‐2944)
33 citations
TL;DR: The finding that these suprathreshold compound stimuli are discriminated on the basis of the local spatial features, and not on differences in their phase spectra as previously thought, allows a reinterpretation of the importance of phase coding in normal vision and of the selective loss of these discriminations that have been previously reported for peripheral vision and in amblyopia.
33 citations
30 Aug 1992
TL;DR: An active vision system for saccadic camera gaze shifts and explorative scene analysis as a new integral approach to image understanding based on a hypercolumnar representation that is able to perform visual search and reproduce findings in the human visual system.
Abstract: Proposes an active vision system for saccadic camera gaze shifts and explorative scene analysis as a new integral approach to image understanding. The model consists of two sensory subsystems: preattentive peripheral feature detection and high resolution foveal image identification based on a hypercolumnar representation. Visual objects are non-explicitly stored in two sparsely coded associative memories separating fixation locations for identities of foveal views. An egocentric interest map integrates bottom-up and top-down information sources and decides when to generate a camera movement. A selective masking of preattentive processes supports a cooperation with cognitive object recognition. The system is easily extendible, copes with occlusions and distortions and can be driven in different modes for exploration tasks. This model is able to perform visual search and reproduce findings in the human visual system. >
33 citations