Perceptual grouping in haptic search: The influence of proximity, similarity, and good continuation.

2012 ◽  
Vol 38 (4) ◽  
pp. 817-821 ◽  
Author(s):  
Krista E. Overvliet ◽  
Ralf Th. Krampe ◽  
Johan Wagemans
Keyword(s):  
Perceptual Grouping ◽  
Good Continuation ◽  
Haptic Search

scholarly journals DESIGN OF ORIENTATION ASSESSMENT FUNCTIONS FOR GESTALT-GROUPING UTILIZING LABELED SAMPLE-DATA

2019 ◽  
Vol XLII-2/W16 ◽  
pp. 169-173
Author(s):  
E. Michaelsen ◽  
J. Meidow
Keyword(s):  
Perceptual Grouping ◽  
Recognition Task ◽  
Mixture Distribution ◽  
Human Perception ◽  
Ground Truth ◽  
Original Form ◽  
Land Use Classification ◽  
Good Continuation ◽  
Data Set ◽  
Gestalt Grouping

<p><strong>Abstract.</strong> Psychological evidence is given that perceptual grouping is an important help for various visual tasks. Object recognition and land use classification from remotely sensed imagery is an example. In machine vision, such a grouping process can be implemented by coding Gestalt laws such as proximity, symmetry, or good continuation. Since geometric relations are rarely fulfilled exactly, soft membership functions are utilized called Gestalt assessments. Hierarchical grouping is possible on increasing scales. Such an approach to hierarchical Gestalt grouping is modified in this paper. In its original form, the approach uses rather heuristic default assessment functions, which are a possible choice as long as no labeled example data are given. The assessment functions can be parameterized so as to improve the perceptual grouping, guiding it by the Gestalten salient to human perception. To this end, we use orientation statistics from the publicly available data set given for the ICCV symmetry recognition competition 2017. Also, with a particular recognition task at hand, labeled example data can serve as the desired foreground. Here we use the ground-truth layer for buildings of the Vaihingen benchmark of the ISPRS. A mixture distribution containing two von Mises-distributions and the uniform component for the clutter in the background is fitted using expectation maximization.</p>

Neural Dynamics for Preattentive Perceptual Grouping: Linking Gestalt Laws and Cortical Synchronisation

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 45-45
Author(s):  
W A Fellenz
Keyword(s):  
Phase Space ◽  
Perceptual Grouping ◽  
Cortical Neurons ◽  
Object Representation ◽  
Neural Dynamics ◽  
Good Continuation ◽  
Relaxation Phase ◽  
Detection Stage ◽  
Gestalt Laws ◽  
Visual Cortical

As revealed by the Gestalt school in the first half of the century, visual perception is governed by certain simple rules which group parts into wholes in accordance to ‘laws’ like grouping by proximity, similarity, closure, symmetry, and good continuation. Although these principles can be investigated by experiment, their underlying neural computation is largely unknown. It has been speculated that synchronisations of visual cortical neurons may serve as the carrier for the observed perceptual grouping phenomenon. We present a neural network for preattentive perceptual grouping derived from neurophysiological and psychophysical findings, incorporating a relaxation phase labeling and diffusion process. The network groups visual features into perceptual entities by (de)synchronising parametric phase labels of simple neural oscillators using a constraint satisfaction mechanism. The local constraints between features, which model the Gestaltist grouping principles of proximity and good continuation, act horizontally in and vertically between feature dimensions to allow for the emergent segregation of globally salient contours in phase space, suppressing false responses generated from the edge detection stage. By applying the grouping mechanism to various contour types ranging from dotted lines to intensity edges we show that the phase-based object representation is able to account for various perceptual phenomena like the closing of small contour gaps and the perception of illusory contours. Based solely on edge responses and local interactions thereupon, the neural dynamics allows the emergent formation of globally distinguishable objects in phase space, which can be extracted by an attentional mechanism tracking the spatially modulated phase information.

Convex Grouping Impedes Detection of Stereoscopic Depth

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 242-242
Author(s):  
Z Liu
Keyword(s):  
Perceptual Grouping ◽  
Image Plane ◽  
Stereoscopic Depth ◽  
Relative Depth ◽  
Objective Method ◽  
Good Continuation ◽  
Depth Discrimination ◽  
Ground Segmentation ◽  
Planar Regions ◽  
Oval Shape

When two image regions are separated by an occluder, the strength of their perceptual grouping behind the occluder depends in part on the possible smoothness of the hidden contour completions (ie, Gestalt ‘good continuation’). We consider if grouping strength also depends on whether the contour completion is convex or concave. We hypothesised that the stronger the grouping between two such regions, the harder it is to resolve their relative stereoscopic depth; and employed accordingly an objective method of relative depth discrimination. The stimulus was in stereo. A horizontal bar in the centre of the image occluded two pairs of planar regions parallel with the image plane. One pair assumed a convex (oval) shape behind the occluder, the other pair a concave (hourglass) shape. The regions in one pair had a slight depth difference. The task was to detect which pair was not coplanar. The convex grouping impeded detection of stereoscopic relative depth (73% vs 86%, F1,10=8.66, p < 0.02). This held even when the convex completion boundaries were less smooth than the concave ones, a result opposite to predictions by Gestalt ‘good continuation’. In a control experiment, the stimulus was viewed with the ‘occluder’ in the background, so grouping was no longer possible. No difference between the two pairs was found. Our results suggest that convexity, known to play a role in figure/ground segmentation, is also significant in perceptual grouping, and can even win out over ‘good continuation’. We also propose an objective method of depth discrimination to study perceptual grouping in general.

scholarly journals Developing the Leuven Embedded Figures Test (L-EFT): testing the stimulus features that influence embedding

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2862 ◽  
Author(s):  
Lee de-Wit ◽  
Hanne Huygelier ◽  
Ruth Van der Hallen ◽  
Rebecca Chamberlain ◽  
Johan Wagemans
Keyword(s):  
Individual Differences ◽  
Perceptual Grouping ◽  
Response Times ◽  
Autism Spectrum ◽  
Good Continuation ◽  
Embedded Figures Test ◽  
Lower Accuracy ◽  
Embedded Figures ◽  
Perceptual Style ◽  
Stimulus Features

BackgroundThe Embedded Figures Test (EFT, developed by Witkin and colleagues (1971)) has been used extensively in research on individual differences, particularly in the study of autism spectrum disorder. The EFT was originally conceptualized as a measure of field (in)dependence, but in recent years performance on the EFT has been interpreted as a measure of local versus global perceptual style. Although many have used the EFT to measure perceptual style, relatively few have focused on understanding the stimulus features that cause a shape to become embedded. The primary aim of this work was to investigate the relation between the strength of embedding and perceptual grouping on a group level.MethodNew embedded figure stimuli (both targets and contexts) were developed in which stimulus features that may influence perceptual grouping were explicitly manipulated. The symmetry, closure and complexity of the target shape were manipulated as well as its good continuation by varying the number of lines from the target that continued into the context. We evaluated the effect of these four stimulus features on target detection in a new embedded figures task (Leuven Embedded Figures Test, L-EFT) in a group of undergraduate psychology students. The results were then replicated in a second experiment using a slightly different version of the task.ResultsStimulus features that influence perceptual grouping, especially good continuation and symmetry, clearly affected performance (lower accuracy, slower response times) on the L-EFT. Closure did not yield results in line with our predictions.DiscussionThese results show that some stimulus features, which are known to affect perceptual grouping, also influence how effectively a stimulus becomes embedded in different contexts. Whether these results imply that the EFT measures individual differences in perceptual grouping ability must be further investigated.

scholarly journals The contribution of shape features and demographic variables to disembedding abilities

2021 ◽  
Author(s):  
Elisa Morgana Cappello ◽  
Giada Lettieri ◽  
Andrea P. Malizia ◽  
Sonia d'Arcangelo ◽  
Giacomo Handjaras ◽  
...  
Keyword(s):  
Educational Attainment ◽  
Perceptual Grouping ◽  
Individual Characteristics ◽  
Shape Features ◽  
Good Continuation ◽  
Highly Educated ◽  
Independence Dimension ◽  
Object Shapes ◽  
Stimulus Features

Humans typically perceive visual patterns in a global manner, and are remarkably capable of extracting object shapes based on properties such as proximity, closure, symmetry, and good continuation. Notwithstanding people’s attitude toward perceptual grouping, the research highlighted differences in disembedding performance across individuals, summarized by the field dependence/independence dimension. Previous studies revealed that age and educational attainment explain part of this variability, whereas the role of sex is still highly debated. Also, which stimulus features primarily influence inter-individual variations in perceptual grouping has to be fully determined.Building upon these premises, we assessed the role of age, level of education and sex on performance at the Leuven-Embedded Figure Test - a proxy of disembedding abilities - in a sample of 391 cisgender individuals. We also investigated whether stimulus symmetry, closure, complexity, and continuation relate to task accuracy as a function of personal characteristics.Overall, target asymmetry and continuation with the embedding context increase task difficulty, whereas target complexity demonstrates a U-shaped relationship with disembedding performance. Further, results unveil sex differences that have not been reported so far in adults and support the association between age, educational attainment, and disembedding abilities. Male individuals also benefit more from target symmetry and closure and are better at recognizing shapes when the embedding context is challenging. Lastly, highly educated adults better recognize asymmetrical and open targets, as well as shapes embedded in complex contexts. Taken together, our findings show how shape features relate to individual characteristics in explaining field independence.

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