Grid illusion

Hermann grid illusion
Hermann grid illusion
The Scintillating grid illusion
The Scintillating grid illusion

A grid illusion is any kind of grid that deceives a person's vision. The two most common types of grid illusions are the Hermann grid illusion and the scintillating grid illusion.

The Hermann grid illusion is an optical illusion reported by Ludimar Hermann in 1870. The illusion is characterized by "ghostlike" grey blobs perceived at the intersections of a white (or light-colored) grid on a black background. The grey blobs disappear when looking directly at an intersection.

The scintillating grid illusion is an optical illusion, discovered by E. Lingelbach in 1994, that is usually considered a variation of the Hermann grid illusion. It is constructed by superimposing white discs on the intersections of orthogonal gray bars on a black background. Dark dots seem to appear and disappear rapidly at random intersections, hence the label "scintillating". When a person keeps his or her eyes directly on a single intersection, the dark dot does not appear. The dark dots disappear if one is too close to or too far from the image.
(Wikipedia)


 

Hermann grid illusion

The Hermann grid illusion is created with a grid of black squares upon a white background. "Ghostlike" gray figures are perceived at the intersections of the white lines. These figures disappear when one looks directly at an intersection. (New World Encyclopedia)

Hermann grid illusion

Hermann grid illusion

Hermann grid illusion: Dark blobs appear at the intersections.

Hermann grid illusion

Hermann grid illusion: Illusion of gray dots at the intersections

Hermann grid illusion: Illusion of gray dots at the intersections.


 

Hermann grid illusion

Hermann grid illusion

Hermann grid illusion: Optical illusion caused by lateral inhibition.

Hermann grid illusion

Hermann grid illusion

Hermann grid illusion
The grey disks are only seen at alley crossings, but not T-junctions.

 

 

Blurred Hermann grid (Bergen illusion)

Bergen illusion

Blurred Hermann grid produced - In 1985, JR Bergen found that if you blur the Hermann grid, you’ll notice a scintillation effect, where black spots appear and disappear at the crossing of the light alleys.

Blurred Hermann grid (Bergen illusion)

Bergen illusion

White spots appear to flash at the crossings of dark alleys.


 

Differences between the scintillating and Hermann grid illusions

. The difference between the Hermann grid illusion and the scintillating illusion is that scintillating illusions have dots already in place at the intersection, whereas there are no dots already in place at the intersections of Hermann grid illusions. Since they are so similar, the two names are commonly used interchangeably. But the scintillating illusion does not occur with an isolated intersection, as in the case of the Hermann grid; observations suggest that a minimum of 3 × 3 evenly spaced intersections with superimposed discs are required to produce the effect. This requirement suggests the participation of global processes of the kind proposed for the linking and grouping of features in an image, in addition to local processes.

 


The Scintillating grid illusion

The Scintillating grid illusion is created with a grid of black squares upon a white gray bars with white discs inserted at each intersection. When viewers moves their eyes around the image, black dots seem to appear and disappear. The illusion is enhanced by eye movement, and decreased by moving too close or too far away from the image. (New World Encyclopedia)

The Scintillating grid illusion

The Scintillating grid illusion

The Scintillating grid illusion

The Scintillating grid illusion


 

A white scintillating grid illusion.

white scintillating grid illusion

White dots seem to appear and disappear at intersections.

The Scintillating grid illusion

The Scintillating grid illusion


 


 

The scintillating grid illusion in a cloth pattern

The scintillating grid illusion in a cloth pattern

Illusory black spots appear to scintillate in the circles at the crosses of the grating.

Hermann and Scintillating Grid illusion in groups of image thumbnails

Hermann Grid illusion in a page of image thumbnails   Scintillating Grid illusion in a page of image thumbnails

Left: A page of image thumbnails creates the Hermann Grid illusion.
Right: Reducing the bright areas at the corners creates the Scintillating Grid illusion.


 

12 Dots Grid Puzzle

12 Dots Grid Puzzle

12 Dots Grid Puzzle

12 Dots Grid Puzzle: Can you spot all 12 dots at first glance?
According to psychology professor Akiyoshi Kitaoka who posted on Facebook on September 10, 2016, this is a type of Ninio's extinction illusion. The twelve black dots cannot be seen at once by most people. (Unfortunately, I can see all 12 dots at once and therefore don't know what all the fuss was about.)

12 Dots Grid Puzzle

12 Dots Grid Puzzle

Try as you might, I bet you can't see any of the 12 dots in this April First Illusion picture!