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Optičke iluzije 
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Post Optičke iluzije
naišla na jedan sajt sa predobrim iluzijama ... npr.

The squares marked A and B are the same shade of gray, yet they appear different. Read inside this article to get proof and explanation why this illusion occurred.

Image

Proof:

By joining the squares marked A and B with two vertical stripes of the same shade of gray, it becomes apparent that both squares are the same.

Image

Explanation:

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.



... fascinatno. :hm

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01 Jul 2009, 00:50
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Post Re: Optičke iluzije
Indeed fascinating.

Opticke iluzije pokazuju koliko je ona nakupina zivcanih stanica koju nosimo u glavi zapravo sofisticiran uredjaj :D

Btw, care to share your link with us? :P

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01 Jul 2009, 01:04
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Post Re: Optičke iluzije
Tu ih ima par zgodnih:
http://www.skytopia.com/project/illusion/illusion.html

A ovo je jednostavno cool :cool
http://www.metacafe.com/watch/1295033/a ... on_solved/

Sve je nađeno preko Stumblea. Stumble rulz :inlove

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01 Jul 2009, 10:46
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Post Re: Optičke iluzije
evo još jedna odlična ...

If you look at the spinning girl’s silhouette below, you will think it is spinning clockwise, probably. When you check her shadow below, momentarily the spinning direction changes in your mind, and now the girl is spinning counter-clockwise. It can be quite hard at the beginning to notice switch of the spinning direction, but eventually you’ll manage. I posted more simple illusion of this kind while ago, and you can see it here. Now, be honest - how long did it take you to see it spin in both directions? Not as easy as the hidden tiger, ayeh? I lost the link to the original artist, but best I could come up with is the place I found it on.


Image


evo i linka odakle to ;)
http://www.moillusions.com/2007/06/spin ... usion.html


gledam to i prvi put mi ide na desno, pogledam na gore i najednom ide na ljevo i gledam wtf. :D

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01 Jul 2009, 11:36
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Post Re: Optičke iluzije
Dosta je očito u kojem smjeru se cura vrti...

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01 Jul 2009, 23:31
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Post Re: Optičke iluzije
dude, ide u oba smjera fyi.

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01 Jul 2009, 23:41
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Post Re: Optičke iluzije
34 framea, taman za jednu revoluciju...

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01 Jul 2009, 23:49
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Post Re: Optičke iluzije
:hm da ... ali poanta je da "vidiš" da u jednom trenu ide i u drugom smjeru.

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02 Jul 2009, 10:10
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Post Re: Optičke iluzije
Pa mogu "vidjeti", ali onda imam osjećaj da je cura neprirodno nagnuta, i da će jadna past :p

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02 Jul 2009, 12:26
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Post Re: Optičke iluzije
najbolja iluzija ... ikad!

Image


You see embedded spirals, right, of green, pinkish-orange, and blue? Incredibly, the green and the blue spirals are the same color. I loaded the image in Photoshop and examined the two spirals. In the two squares displayed below, the one on the left is colored using the same color from the blue spiral, and on the right using the green spiral.

Image


Like I said, incredible! For pedantry sake, the RGB colors in both spirals are 0, 255, 150. So they are mostly green with a solid splash of blue.

The reason they look different colors is because our brain judges the color of an object by comparing it to surrounding colors. In this case, the stripes are not continuous as they appear at first glance. The orange stripes don’t go through the "blue" spiral, and the magenta ones don’t go through the "green" one.
Here’s a zoom to make this more clear:

Image


See? The orange stripes go through the "green" spiral but not the "blue" one. So without us even knowing it, our brains compare that spiral to the orange stripes, forcing it to think the spiral is green. The magenta stripes make the other part of the spiral look blue, even though they are exactly the same color. If you still don’t believe me, concentrate on the edges of the colored spirals. Where the green hits the magenta it looks bluer to me, and where the blue hits the orange it looks greener. Amazing.

The overall pattern is a spiral shape because our brain likes to fill in missing bits to a pattern. Even though the stripes are not the same color all the way around the spiral , the overlapping spirals makes our brain think they are. The very fact that you have to examine the picture closely to figure out any of this at all shows just how easily we can be fooled.

This is why I tell people over and over again: you cannot trust what you see even with your own eyes. Your eyes are not cameras faithfully taking pictures of absolute truth of all that surrounds you. They have filters, and your brain has to interpret the jangled mess it gets fed. Colors are not what they appear, shapes are not what they appear (that zoomed image above is square, believe it or not), objects are not what they appear.

So the next time someone swears they saw Jesus, or a UFO, or a ghost, show them this picture. What you see in life is absolutely and provably not what you get.

http://blogs.discovermagazine.com/badas ... the-green/

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25 Jul 2009, 21:17
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Post Re: Optičke iluzije
http://www.neatorama.com/2009/08/11/fou ... d-circles/

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19 Aug 2009, 09:39
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Post Re: Optičke iluzije
http://discovermagazine.com/photos/09-w ... illusions/

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19 Jun 2010, 13:32
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