The Scintillating Grid

2017 ◽  
Author(s):  
Bernd Lingelbach
Keyword(s):  
Visual Perception ◽  
Receptive Fields ◽  
European Conference ◽  
Low Pass ◽  
Hermann Grid Illusion

The scintillating grid was first presented at the European Conference on Visual Perception in Tübingen in 1995. At the time, the prevailing explanation of the Hermann grid illusion was in terms of the arrangement of the receptive fields on the retina. The minor modification of having a grey instead of a white grid with white dots at the intersections produced a strikingly new and powerful illusion. Instead of the white dots, dark black dots are seen to “blink” and appear even darker in intensity than the black printer’s ink of the square. They then disappear again to reappear immediately somewhere else. The dark diagonals that appear from time to time fitted more to low-pass filtering. The study of low-pass filtered Hermann grids led to the discovery of the scintillating grid and several variants. To this day this illusion still has not been fully explained.

scholarly journals A method for presenting biomedical images based on a model of receptive fields of human visual perception

2021 ◽  
Vol 2091 (1) ◽  
pp. 012027
Author(s):  
V E Antsiperov ◽  
V A Kershner
Keyword(s):  
Image Processing ◽  
Visual Perception ◽  
Bayesian Learning ◽  
Signal To Noise Ratio ◽  
Receptive Fields ◽  
New Method ◽  
Human Visual Perception ◽  
Signal To Noise ◽  
Biomedical Images ◽  
Local Characteristics

Abstract The paper is devoted to the development of a new method for presenting biomedical images based on local characteristics of the intensity of their shape. The proposed method of image processing is focused on images that have low indicators of the intensity of the recorded radiation, resolution, contrast and signal-to-noise ratio. The method is based on the principles of machine (Bayesian) learning and on samples of random photo reports. This paper presents the results of the method and its connection with modern approaches in the field of image processing.

The Hermann Grid Illusion: A Tool for Studying Human Perceptive Field Organization

Perception ◽  
1994 ◽  
Vol 23 (6) ◽  
pp. 691-708 ◽  
Author(s):  
Lothar Spillmann
Keyword(s):  
Receptive Field ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Retinal Eccentricity ◽  
Cortical Cells ◽  
Perceptive Field ◽  
Neurophysiological Mechanisms ◽  
Field Organization ◽  
Hermann Grid Illusion ◽  
Retinal Receptive Fields

Psychophysical research on the Hermann grid illusion is reviewed and possible neurophysiological mechanisms are discussed. The illusion is most plausibly explained by lateral inhibition within the concentric receptive fields of retinal and/or geniculate ganglion cells, with contributions by the binocular orientation-specific cortical cells. Results may be summarized as follows: (a) For a strong Hermann grid illusion to be seen bar width must be matched to the mean size of receptive-field centers at any given retinal eccentricity. (b) With the use of this rationale, the diameter of foveal perceptive-field centers (the psychophysical correlate of receptive-field centers) has been found to be in the order of 4–5 min arc and that of total fields (centers plus surrounds) 18 min arc. These small diameters explain why the illusion tends to be absent in foveal vision. (c) With increasing distance from the fovea, perceptive-field centers increase to 1.7 deg at 15 deg eccentricity and then to 3.4 deg at 60 deg eccentricity. This doubling in diameter agrees with the change in size of retinal receptive-field centers in the monkey. (d) The Hermann grid illusion is diminished with dark adaptation. This finding is consistent with the reduction of the center—surround antagonism in retinal receptive fields. (e) The illusion is also weakened when the grid is presented diagonally, which suggests a contribution by the orientation-sensitive cells in the lateral geniculate nucleus and visual cortex. (f) Strong induction effects, similar to the bright and dark spots in the Hermann grid illusion, may be elicited by grids made of various shades of grey; and by grids varying only in chroma or hue. Not accounted for are: the illusory spots occurring in an outline grid ie with hollow squares, and the absence of an illusion when extra bars are added to the grid. Alternative explanations are discussed for the spurious lines connecting the illusory spots along the diagonals and the fuzzy dark bands traversing the rhombi in modified Hermann grids.

Global Factors in the Hermann Grid Illusion

Perception ◽  
1984 ◽  
Vol 13 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Jeremy M Wolfe
Keyword(s):  
Receptive Fields ◽  
Illusion Magnitude ◽  
Local Model ◽  
Hermann Grid Illusion

Most explanations of the Hermann grid illusion are local in nature. For example, in Baumgartner's model the effect is generated by the response of cells having concentric on—off or off—on receptive fields. Such models predict that the magnitude of the illusion at a given intersection should be the same whether that intersection is viewed in isolation or in conjunction with other intersections in a grid. Two experiments are reported. The first demonstrates that illusion magnitude grows with the number of intersections. The second shows that this growth is seen when the intersections are arranged in an orderly grid but not when they are placed irregularly. These results suggest that a purely local model for the Hermann grid illusion is not a complete explanation. Global factors must be involved.

scholarly journals The neon fruit illusion: a fresh recipe for colour science demonstrations

2018 ◽  
Author(s):  
Joshua Harvey ◽  
Takuma Morimoto ◽  
Manuel Spitschan
Keyword(s):  
Visual Perception ◽  
Fruits And Vegetables ◽  
Visual Illusion ◽  
Low Cost ◽  
European Conference ◽  
The Public ◽  
Lighting Conditions ◽  
Science Demonstration

At this year's European Conference on Visual Perception we debuted a novel colour science demonstration---and visual illusion---for the Un mare di illusioni exhibition. Under carefully curated lighting conditions, cycling through different illuminant spectra, certain fruits and vegetables appear to glow and dim in an unchanging environment. Encouraged by the positive reactions it received, and the numerous and specific questions from conference delegates, we here describe what this illusion is, why we believe it may work, and how this particular low-cost setup may be assembled and demonstrated for the amazement of your friends, students, and members of the public.

The Curved Grid Non-Illusions

2017 ◽  
Author(s):  
János Geier ◽  
Mariann Hudák
Keyword(s):  
Statistical Analysis ◽  
Retinal Ganglion Cells ◽  
Line Width ◽  
Ganglion Cells ◽  
Receptive Fields ◽  
Retinal Ganglion ◽  
Illusory Effect ◽  
Grid Line ◽  
Wide Range ◽  
Hermann Grid Illusion

The generally accepted explanation of the Hermann grid illusion is Baumgartner’s hypothesis that the illusory effect is generated by the response of retinal ganglion cells with concentric ON-OFF or OFF-ON receptive fields. To challenge this explanation, some simple distortions to the grid lines were introduced that make the illusion disappear totally, while all preconditions of Baumgartner’s hypothesis remained unchanged. Psychophysical experiments in which the distortion tolerance was measured showed the level of distortion at which the illusion disappears at a given type of distortion for a given subject. Statistical analysis shows that the distortion tolerance is independent of grid-line width within a wide range and of the type of distortion, except when one side of each line remains straight. The conclusion is the main cause of the Hermann grid illusion is the straightness of the edges of the grid lines. Similar results have been obtained in the scintillating grid.

European Conference on Visual Perception

2006 ◽  
Vol 31 (4) ◽  
pp. 368-369
Author(s):  
◽  
Yuri Shelepin
Keyword(s):  
Visual Perception ◽  
European Conference
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