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Optical Illusio?s


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The squares that A and B are in are exactly the same colour. Want me to explain?

 

 

 

The visual system needs to determine the color of objects in the world. In this case the problem is to determine the gray shade of the checks on the floor. Just measuring the light coming from a surface (the luminance) is not enough: a cast shadow will dim a surface, so that a white surface in shadow may be reflecting less light than a black surface in full light. The visual system uses several tricks to determine where the shadows are and how to compensate for them, in order to determine the shade of gray "paint" that belongs to the surface.

 

 

 

The first trick is based on local contrast. In shadow or not, a check that is lighter than its neighboring checks is probably lighter than average, and vice versa. In the figure, the light check in shadow is surrounded by darker checks. Thus, even though the check is physically dark, it is light when compared to its neighbors. The dark checks outside the shadow, conversely, are surrounded by lighter checks, so they look dark by comparison.

 

 

 

A second trick is based on the fact that shadows often have soft edges, while paint boundaries (like the checks) often have sharp edges. The visual system tends to ignore gradual changes in light level, so that it can determine the color of the surfaces without being misled by shadows. In this figure, the shadow looks like a shadow, both because it is fuzzy and because the shadow casting object is visible.

 

 

 

The "paintness" of the checks is aided by the form of the "X-junctions" formed by 4 abutting checks. This type of junction is usually a signal that all the edges should be interpreted as changes in surface color rather than in terms of shadows or lighting.

 

 

 

As with many so-called illusions, this effect really demonstrates the success rather than the failure of the visual system. The visual system is not very good at being a physical light meter, but that is not its purpose. The important task is to break the image information down into meaningful components, and thereby perceive the nature of the objects in view.

johannase.jpg

Thank you to tripsis for an awesome sig!

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Holy crap, the dancer finally worked! My god that's incredible.... how you can convince your mind to think it's seeing something like that. Wow! I can't imagine her going clockwise now though.

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I saw her going clockwise for 20 seconds then started being a [bleep]. Every half of a second she kept changing direction and at one point she was going in both directions at the same time.

 

 

 

:twss: :twss: :ohnoes:

So don't let anyone tell you you're not worth the earth,

These streets are your streets, this turf is your turf,

Don't let anyone tell you that you've got to give in,

Cos you can make a difference, you can change everything,

Just let your dreams be your pilot, your imagination your fuel,

Tear up the book and write your own damn rules,

Use all that heart, hope and soul that you've got,

And the love and the rage that you feel in your gut,

And realise that the other world that you're always looking for,

Lies right here in front of us, just outside this door,

And it's up to you to go out there and paint the canvas,

After all, you were put on the earth to do this,

So shine your light so bright that all can see,

Take pride in being whoever the [bleep] you want to be.

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After about 30 seconds I could get the dancer to spin either way easily, I can even make her spin half way clock wise and then half way counter clockwise, and then keep repeating that. The trick for me is to watch her hair.

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Wow, that dancer one is strange. I can't control her though, took a while to get her spinning the other way :\.

 

 

 

And yay! I see Escher!

 

RelativityESCHER-410px.jpg

 

I studied him for my Art two years ago, mind-confusing stuff :P

 

 

 

And I can see the colour similarities on the chess one if I put my fingers around the squares surrounding B, effectively blocking them out.

rc1tzc.png

☢ CAUTION ☢ CAUTION ☢ CAUTION ☢ CAUTION ☢

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[hide=]The squares that A and B are in are exactly the same colour. Want me to explain?

 

 

 

The visual system needs to determine the color of objects in the world. In this case the problem is to determine the gray shade of the checks on the floor. Just measuring the light coming from a surface (the luminance) is not enough: a cast shadow will dim a surface, so that a white surface in shadow may be reflecting less light than a black surface in full light. The visual system uses several tricks to determine where the shadows are and how to compensate for them, in order to determine the shade of gray "paint" that belongs to the surface.

 

 

 

The first trick is based on local contrast. In shadow or not, a check that is lighter than its neighboring checks is probably lighter than average, and vice versa. In the figure, the light check in shadow is surrounded by darker checks. Thus, even though the check is physically dark, it is light when compared to its neighbors. The dark checks outside the shadow, conversely, are surrounded by lighter checks, so they look dark by comparison.

 

 

 

A second trick is based on the fact that shadows often have soft edges, while paint boundaries (like the checks) often have sharp edges. The visual system tends to ignore gradual changes in light level, so that it can determine the color of the surfaces without being misled by shadows. In this figure, the shadow looks like a shadow, both because it is fuzzy and because the shadow casting object is visible.

 

 

 

The "paintness" of the checks is aided by the form of the "X-junctions" formed by 4 abutting checks. This type of junction is usually a signal that all the edges should be interpreted as changes in surface color rather than in terms of shadows or lighting.

 

 

 

As with many so-called illusions, this effect really demonstrates the success rather than the failure of the visual system. The visual system is not very good at being a physical light meter, but that is not its purpose. The important task is to break the image information down into meaningful components, and thereby perceive the nature of the objects in view.[/hide]

 

And:

 

[hide=]772px-Same_color_illusion_proof2.png[/hide]

zBSYE.png

^ Blog.

Zh0c4.gif

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You guys are all seeing the dancer clockwise while I see her counter-clockwise most of the time. Does that count as she can move both ways?

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I just spent about 6 minutes staring at the dancer and she won't change. How the hell can you see her go anti-clockwise. She does speed up and slow down all the time though, but thats probaly just the image.

Doomy edit: I like sheep

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I like the Jesus optical Illusion but can't find it because my comp is acting up.

 

 

 

Got it, love this one :P

 

[hide=]

Stare at the 4 little dots in the middle of the image for 30/40 seconds, then look away, preferably onto a black, bright surface like a wall or ceiling... should see Jesus.

 

 

 

jesusoi.th.jpg

[/hide]
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How the hell can you see her go anti-clockwise.

 

:lol:

 

 

 

You gotta force yourself to imagine her outstretched arm is going behind, not in front of, her.

 

I just kinda look and shes going counter-clockwise lol

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