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Old 10-07-2012, 01:18 AM
 
Location: Chesterfield,Virginia
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Are square A and square B the same color?



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APOD: 2012 October 7 - The Same Color Illusion

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Old 10-07-2012, 01:48 AM
 
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Yes they are, I actually created a similar illusion on website accidentally once. The background behind the link text is a gadient. Where the red arrows are pointing too are the exact same color. If you look between the space between "Atom" and "upload file" it looks like it's gradient that goes from light to darker left to right. It's not.

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Old 10-07-2012, 07:39 AM
 
Location: God's Gift to Mankind for flying anything
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You really do not need that complex of a picture to demonstrate the illusion.

See attached pic where I cut out just a section of the picture.

On the left, they still *look* a different colour.
Then I copy and pasted each block
on an all white back ground (same border colours now)
The colours are now the same.

It is the border colour difference and the gradient in between,
that makes the human eye think it is different.

Interesting, to say the least.
Attached Thumbnails
Is A Equal To B?-colour_illusion.jpg  
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Old 10-07-2012, 02:26 PM
 
Location: Somewhere in northern Alabama
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Technically, pure grey is not a color. Greys are tints and shades. That said, that is one of the better and more persistent illusions, and it incorporates a few tricks.

The left side of the checkered board is not parallel to the right side, does not conform to orthographic or perspective projections.
The right side is slightly longer.
The front and back obey more the rules of perspective.
In addition to the shadow of the cylinder creating gradients, in perspective views we expect the objects near the horizon (more in the distance) to be lighter, and our eyes compensate for that as well, yet we view this as an orthographic view.
The two dark squares in the front right corner are also the same tint/shade as A & B
The apparent light source from the upper right makes the eyes overcompensate for the shadow on B and the "light" on A.

Cleverly done.
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Old 10-07-2012, 09:03 PM
 
Location: God's Gift to Mankind for flying anything
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Interesting theory that proves that additional stuff around the illusion enhances the effect even more, altho it does work with just a simple form.
Jut look at the two drawings I attached above.
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Old 10-07-2012, 09:32 PM
 
Location: Somewhere in northern Alabama
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Aware of that. Was puzzled why I couldn't "flip" the illusion in my mind like I normally can.
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Old 10-08-2012, 02:48 AM
 
Location: God's Gift to Mankind for flying anything
5,173 posts, read 10,492,139 times
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Quote:
Originally Posted by harry chickpea View Post
Aware of that. Was puzzled why I couldn't "flip" the illusion in my mind like I normally can.
Like when you look at the goal structure of a soccer field ?
For me the rear beams that support the front beams often flip back and forth ...
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Old 10-08-2012, 08:54 AM
 
Location: Somewhere in northern Alabama
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Yep, I think (not a soccer watcher). IIRC, the term for it is figure ground reversal.
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Old 10-08-2012, 12:37 PM
 
Location: Chesterfield,Virginia
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Like spokes on a wheel (bike or auto) seem to reverse their spin if you watch long enough.
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Old 10-08-2012, 01:49 PM
 
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Quote:
Originally Posted by MrClose View Post
Like spokes on a wheel (bike or auto) seem to reverse their spin if you watch long enough.
That has to do with the speed of the wheel and because your eye can only see so many "frames per second". Your eye captures the spokes in a position that translates into them spinning into the opposite direction. Lets say we have a wheel with one spoke and it's spinning clockwise. Suppose the first time your eye sees it at 12 and the next time it's able to see it at 11, next 10......... While the wheel is spinning clockwise what your sees is it moving counterclockwise.
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