Dip Optical Illusions

8/4/2019 Dip Optical Illusions

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Can you see dark blotches on the white 'junctions' inbetween the corners of these black squares?


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Which semicircle isbrighter - the left orthe right half?


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One of the most famous optical

illusions, reproduced in colour!


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What line is longer;from a to b, or from b to c?

Amazingly, they're both the same length. This is perhaps the most extreme example of I have found that distortsperception of length.


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Also created by Akiyoshi, the lines in this picture below are completely parallelwould you believe?


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This amazing illusion to the right was created by Akiyoshi Kitaoka. It alreadylooks quite 'wavy', but try slowly moving the mouse cursor up and down thecenter of the image - and focus on the cursor. You should see the picture

'waving' in an incredible way.
http://www.ritsumei.ac.jp/~akitaoka/index-e.htmlhttp://www.ritsumei.ac.jp/~akitaoka/index-e.html


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At first, there doesn't seem anything unusual about this picture. I mean, it's just a bunch of diagonallines and a slightly distorted square in the middle - right? Wrong.

Believe it or not, the 4 lines that make up the square are actually perfectly straight. In fact it /is/ aperfect square. For proof of this, the animation will swap between the two frames so you can see the

square remains the same. Also check by loading the pic into your favourite art package.


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Rotating dot whirlpoolWow! Try staring at this for more than 5 seconds

without going crazy. Then try following it round! =)Curves constantly die out and then re-evolve as

part of another curve.


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Is the following object physicallypossible?


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Which line connects to line C? A or B?


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Look at the grouping of stairs below. How can they keep climbing?


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Is this knot pairing of trianglesphysically possible?


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Despite their appearance, the top lines on each ofthese trapezoids is the exact same size!


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Can you figure out what this is apicture of?


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Answer:Cows Head


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?????


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The gear wheels should appear to SLOWLY rotate. The one on the left side of the screenshould turn clockwise and the one on the right side of the screen should turn counter-

clockwise.


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The green is identical throughout this illusion.


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Drawing appears oblique but all thesmall squares have same size


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Robots Appear to Dance


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Impossible Construction


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???????


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Cubes Appear to be Deformed


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The image appears to movebackward and forward


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Look at the two circles below. Would you believe they are the same color?


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Does this scene look real to you?It is painting.


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In this classic optical illusion picture, palm trees appear to turn into camels.
http://www.eyetricks.com/3202.htm


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These three identical cars appear to be three different sizes.Would you believe that they are all the same size? Try measuring them to make sure.


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This image makes it appear that the VW Beetles are being pulled inward


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Does this lucky clover appear to bein motion?


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How is this Lego creation possible? These types of illusions can be created in real life -it's all about the angle.

In this optical illusion if you follow the movement of the rotating pink dot with your eyes


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In this optical illusion, if you follow the movement of the rotating pink dot with your eyes,the dots will remain only one color, pink. However, if you stare at the black + in thecenter, the moving dot will turn green.Keep concentrating on the black + in the center of the picture. After a short period, all thepink dots will slowly disappear and you will only see a single green dot moving in a circle.


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The following are common tests used to detect color blindness.Can you read the numbers hidden in each square?You should see 58 (upper left), 18 (upper right), E (lower left) and 17 (lower right).If you cannot see any of the above numbers/letters, you may suffer from color blindness.


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Mach Band Effect

The what? The Machband describes an effect where the human mind subconsciouslyincreases the contrast between two surfaces with different luminance. It can be seen onthe index page of this website.

The luminance of the squares above increases in a stepwise fashion. However although

the luminance within each block is constant the apparent lightness of each strip seemsto vary across its length. Close to the left edge of the strip it appears lighter than at the

centre, and close to the right edge of the strip it appears darker than at the centre. Thevisual system is exaggerating the difference in luminance (contrast) at each edge inorder top detect it. Try holding a pencil over an edge in this image and see how theapparent difference in lightness of two adjacent strips changes. They become muchharder to tell apart. The edge detection is working to enhance object separation.

Mach banding is caused by lateral inhibition of the receptors in the eye. As receptorsreceive light they draw light-sensitive chemical compounds from adjacent regions, thusinhibiting the response of receptors in those regions. Receptors directly on the lighter

side of the boundary can pull in unused chemicals from the darker side, and thusproduce a stronger response. Receptors on the on the darker side of the boundary,however, produce a weaker effect because of that same migration.


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Mach bands are an optical illusion named after Ernst Mach consisting of an image of two widebands, one light and one dark, separated by a narrow strip with a light-to-dark gradient. Humansperceive two narrow bands of different brightness on either side of the gradient that are notpresent in the original image. The effect is like that of a spatial high-boost filter

The illusion is usually supposed to be caused by lateral inhibition of the receptors in the eye.According to lateral inhibition, given that the gradient is horizontally oriented, the brain

interprets the image as a collection of vertical lines. Every stripe has a value but the braincalculates the contrast of a stripe in relation to neighbor stripes. Stripes at the edges of thegradient have less lateral inhibition than the stripes in the uniform area so they appear as ifthey are brighter or darker than their real value.
http://en.wikipedia.org/wiki/Optical_illusionhttp://en.wikipedia.org/wiki/Ernst_Machhttp://en.wikipedia.org/wiki/Unsharp_maskinghttp://en.wikipedia.org/wiki/Lateral_inhibitionhttp://en.wikipedia.org/wiki/Contrasthttp://en.wikipedia.org/wiki/Contrasthttp://en.wikipedia.org/wiki/Lateral_inhibitionhttp://en.wikipedia.org/wiki/Unsharp_maskinghttp://en.wikipedia.org/wiki/Unsharp_maskinghttp://en.wikipedia.org/wiki/Unsharp_maskinghttp://en.wikipedia.org/wiki/Ernst_Machhttp://en.wikipedia.org/wiki/Optical_illusion


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Match Bands

Illusory Mach Bands result when gradientsfrom darker to lighter shades are created.The thin light and dark bands are illusory.

Below the effect is doubled


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Match Bands

Mach Bands also occur with a relatedcircular effect.

Notice the the slight glow that extends.Addition a second gradient enhances the

effect and almost seems to produce anentire glowing area..

Addition of a third gradient produces an even stronger effect.

Now the glow is striking and the centeryellow seems much brighter that the yellow

in each corner. Also, there is a difuse butstrong subjective contour effect


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Match Bands

Move closer to and further from the screenwhile looking at the center of the figure.There is a change in apparent brightness.This effect is covered in more detail in thesection on Dynamic Luminance.

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