Time Course of Perceptual Grouping by Color

2003 ◽  
Vol 14 (1) ◽  
pp. 26-30 ◽  
Author(s):  
Melissa F. Schulz ◽  
Thomas Sanocki
Keyword(s):  
Depth Perception ◽  
Visual Processing ◽  
Perceptual Grouping ◽  
Retinal Image ◽  
Time Course ◽  
Amodal Completion ◽  
Stereoscopic Depth ◽  
Short Exposure ◽  
Surface Color ◽  
Color Similarity

Does perceptual grouping operate early or late in visual processing? One position is that the elements in perceptual layouts are grouped early in vision, by properties of the retinal image, before perceptual constancies have been determined. A second position is that perceptual grouping operates on a postconstancy representation, one that is available only after stereoscopic depth perception, lightness constancy, and amodal completion have occurred. The present experiments indicate that grouping can operate on both a precon-stancy representation and a postconstancy representation. Perceptual grouping was based on retinal color similarity at short exposure durations and based on surface color similarity at long durations. These results permit an integration of the preconstancy and postconstancy positions with regard to grouping by color.

Perceptual Grouping: It's Later Than You Think

2002 ◽  
Vol 11 (3) ◽  
pp. 101-106 ◽  
Author(s):  
Stephen E. Palmer
Keyword(s):  
Depth Perception ◽  
Perceptual Grouping ◽  
Retinal Image ◽  
Conscious Perception ◽  
Two Dimensional ◽  
Unanswered Question ◽  
Standard View ◽  
Dimensional Image ◽  
Two Dimensional Image ◽  
Binocular Depth

Recent research on perceptual grouping is described with particular emphasis on the level at which grouping factors operate. Contrary to the standard view of grouping as an early, two-dimensional, image-based process, experimental results show that it is strongly influenced by binocular depth perception, lightness constancy, amodal completion, and illusory figures. Such findings imply that at least some grouping processes operate at the level of conscious perception rather than the retinal image. Whether classical grouping processes also operate at an early, preconstancy level is an important, but currently unanswered question.

scholarly journals Response bias in grouping

2004 ◽  
Vol 14 (27) ◽  
pp. 45-48
Author(s):  
Sergio Cesare Masin
Keyword(s):  
Response Bias ◽  
Perceptual Grouping ◽  
Surface Color ◽  
Empirical Results ◽  
Color Similarity

Surface color similarity may cause the perceptual grouping of uniform achromatic surfaces on an achromatic background both when the background is homogeneous and when the background contains achromatic context surfaces. Empirical results reported here show that the grouping response due to the similarity in color of test surfaces is also affected by context surfaces. It is proposed that this response bias results from interference of the grouping response caused by the similarity in color of test surfaces with an implicit grouping response caused by the similarity in color between context surfaces and test surfaces.

scholarly journals The Rapid Extraction of Gist—Early Neural Correlates of High-level Visual Processing

2012 ◽  
Vol 24 (2) ◽  
pp. 521-529 ◽  
Author(s):  
Frank Oppermann ◽  
Uwe Hassler ◽  
Jörg D. Jescheniak ◽  
Thomas Gruber
Keyword(s):  
Visual Processing ◽  
Time Course ◽  
Occipital Cortex ◽  
Stimulus Onset ◽  
Gamma Band ◽  
Oscillatory Activity ◽  
Rapid Extraction ◽  
The Right ◽  
High Level ◽  
Individual Objects

The human cognitive system is highly efficient in extracting information from our visual environment. This efficiency is based on acquired knowledge that guides our attention toward relevant events and promotes the recognition of individual objects as they appear in visual scenes. The experience-based representation of such knowledge contains not only information about the individual objects but also about relations between them, such as the typical context in which individual objects co-occur. The present EEG study aimed at exploring the availability of such relational knowledge in the time course of visual scene processing, using oscillatory evoked gamma-band responses as a neural correlate for a currently activated cortical stimulus representation. Participants decided whether two simultaneously presented objects were conceptually coherent (e.g., mouse–cheese) or not (e.g., crown–mushroom). We obtained increased evoked gamma-band responses for coherent scenes compared with incoherent scenes beginning as early as 70 msec after stimulus onset within a distributed cortical network, including the right temporal, the right frontal, and the bilateral occipital cortex. This finding provides empirical evidence for the functional importance of evoked oscillatory activity in high-level vision beyond the visual cortex and, thus, gives new insights into the functional relevance of neuronal interactions. It also indicates the very early availability of experience-based knowledge that might be regarded as a fundamental mechanism for the rapid extraction of the gist of a scene.

The “Mosaic Stage” in Amodal Completion as Characterized by Magnetoencephalography Responses

2006 ◽  
Vol 18 (8) ◽  
pp. 1394-1405 ◽  
Author(s):  
Gijs Plomp ◽  
Lichan Liu ◽  
Cees van Leeuwen ◽  
Andreas A. Ioannides
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Early Stage ◽  
Amodal Completion ◽  
Peak Latency ◽  
Per Se

We investigated the process of amodal completion in a same-different experiment in which test pairs were preceded by sequences of two figures. The first of these could be congruent to a global or local completion of an occluded part in the second figure, or a mosaic interpretation of it. We recorded and analyzed the magnetoencephalogram for the second figures. Compared to control conditions, in which unrelated primes were shown, occlusion and mosaic primes reduced the peak latency and amplitude of neural activity evoked by the occlusion patterns. Compared to occlusion primes, mosaic ones reduced the latency but increased the amplitude of evoked neural activity. Processes relating to a mosaic interpretation of the occlusion pattern, therefore, can dominate in an early stage of visual processing. The results did not provide evidence for the presence of a functional “mosaic stage” in completion per se, but characterize the mosaic interpretation as a qualitatively special one that can rapidly emerge in visual processing when context favors it.

Thematic object pairs produce stronger and faster perceptual grouping than taxonomic pairs

2021 ◽  
Author(s):  
Joseph Nah ◽  
Joy Geng
Keyword(s):  
Visual Processing ◽  
Perceptual Grouping ◽  
Semantic Information ◽  
Semantic Knowledge ◽  
Perceptual Unit ◽  
Critical Difference ◽  
Common Event ◽  
Taxonomic Relationships ◽  
Different Types ◽  
Fundamental Units

While objects are fundamental units of vision that convey meaning, how different types of semantic knowledge affect perception is not fully understood. In contrast, the concept literature divides semantic information into taxonomic and thematic types. Taxonomic relationships reflect categorization by similarities (e.g., dog – wolf); thematic groups are based on complementary relationships shared within a common event (e.g., swimsuit – goggles; pool). A critical difference between these two information types is that thematic relationships are learned from the experienced co-occurrence of objects whereas taxonomic relationships are learned abstractly. In two studies, we test the hypothesis that visual processing of thematically related objects is more rapid because they serve as mutual visual primes and form a perceptual unit. The results demonstrate that learned co-occurrence not only shapes semantic knowledge, but also affects low level visual processing, revealing a link between how information is acquired (e.g., experienced vs. unobserved) and how it modulates perception.

Influence of sonic noise on human stereoscopic depth perception

AIHAJ ◽  
1979 ◽  
Vol 40 (5) ◽  
pp. 427-435 ◽  
Author(s):  
EDWARD R. HERMANN ◽  
CAROLYN S. HESSE ◽  
E. ROBINSON HOYLE ◽  
ANNE C. LEOPOLD ◽  
JOHN J. STANDARD
Keyword(s):  
Depth Perception ◽  
Stereoscopic Depth

scholarly journals Defining the Units of Competition: Influences of Perceptual Organization on Competitive Interactions in Human Visual Cortex

2010 ◽  
Vol 22 (11) ◽  
pp. 2417-2426 ◽  
Author(s):  
Stephanie A. McMains ◽  
Sabine Kastner
Keyword(s):  
Visual Cortex ◽  
Perceptual Organization ◽  
Visual Processing ◽  
Perceptual Grouping ◽  
Neural Representation ◽  
Competitive Interactions ◽  
Illusory Figure ◽  
Processing Stream ◽  
Neural Processes ◽  
Early Visual Cortex

Multiple stimuli that are present simultaneously in the visual field compete for neural representation. At the same time, however, multiple stimuli in cluttered scenes also undergo perceptual organization according to certain rules originally defined by the Gestalt psychologists such as similarity or proximity, thereby segmenting scenes into candidate objects. How can these two seemingly orthogonal neural processes that occur early in the visual processing stream be reconciled? One possibility is that competition occurs among perceptual groups rather than at the level of elements within a group. We probed this idea using fMRI by assessing competitive interactions across visual cortex in displays containing varying degrees of perceptual organization or perceptual grouping (Grp). In strong Grp displays, elements were arranged such that either an illusory figure or a group of collinear elements were present, whereas in weak Grp displays the same elements were arranged randomly. Competitive interactions among stimuli were overcome throughout early visual cortex and V4, when elements were grouped regardless of Grp type. Our findings suggest that context-dependent grouping mechanisms and competitive interactions are linked to provide a bottom–up bias toward candidate objects in cluttered scenes.

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