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Satch
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 Posted: Thu Jul 14, 2005 11:37 am Post subject: Optical illusions |
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I was interested where morphing was actually coming from. We all know it from the Terminator movies and it was a popular effect used in many videos. It seems that one of the first drawings came from the dutch artist M.C. Esher. He was also a master in creating optical illusion drawings.
Here is one of the coolest optical illusions I found on the internet. Just focus on the cross and after a while all the circles but one dissapear.
Does anyone know the scientific explanation for this?
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Last edited by Satch on Thu Jul 14, 2005 3:09 pm; edited 1 time in total |
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bennie
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| Posted: Thu Jul 14, 2005 11:56 am Post subject: |
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Nice one Satch !!! 
Did not know this one. You are right the circles do disappear after getting green .. !
Most of the time the explanaitions do not add much though.
You know this very, very simple one (posted this one earlier in Gen. Discussions)
They are so simple ..yet you cannot see what is wrong .
The simple drawings:
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MartinaWarren
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Joined: 22 Dec 2004
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| Posted: Thu Jul 14, 2005 12:28 pm Post subject: Re: Optcal illusions |
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| Satch wrote: | I was interested where morphing was actually coming from. We all know it from the Terminator movies and it was a popular effect used in many videos. It seems that one of the first drawings came from the dutch artist M.C. Esher. He was also a master in creating optical illusion drawings.
Here is one of the coolest optical illusions I found on the internet. Just focus on the cross and after a while all the circles but one dissapear.
Does anyone know the scientific explanation for this?
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Wow when i look at that, and stare at the cross. I only then see when moving dot, and it turns color to green 
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marcus
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| Posted: Thu Jul 14, 2005 2:47 pm Post subject: |
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I am getting some new contact lenses this weekend. A couple of weeks ago they tested me on a machine to check if I had any eye defects. The test involved focusing on a dot in the center of the screen. Small lights flashed around the dot and you had to press a button once for each light you saw.
They showed me a chart at the end of the test which showed that I had correctly got all of the dots except the one in the blind spot which I was not supposed to see. From memory it looks like the circles in the optical illusion are just in the peripheral vision area, which means if you are staring at the dot you can only just see them to start with. My guess is they disappear as your attention focuses to your central vision area.
I kept blinking so the circles never really disappeared for me. Funny they didn't go green for me either  |
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sexyman
Rank: Mr. Fabulous
Joined: 19 Jun 2005
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| Posted: Fri Jul 15, 2005 2:05 am Post subject: Re: Optcal illusions |
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| MartinaWarren wrote: | | Wow when i look at that, and stare at the cross. I only then see when moving dot, and it turns color to green |
me too |
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Satch
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| Posted: Fri Jul 15, 2005 2:08 am Post subject: Re: Optcal illusions |
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| sexyman wrote: | | MartinaWarren wrote: | | Wow when i look at that, and stare at the cross. I only then see when moving dot, and it turns color to green |
me too |
Just look longer and stare at the cross. After a while there's only 1 green circle left!
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sexyman
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| Posted: Fri Jul 15, 2005 2:10 am Post subject: Re: Optcal illusions |
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| Satch wrote: | | sexyman wrote: | | MartinaWarren wrote: | | Wow when i look at that, and stare at the cross. I only then see when moving dot, and it turns color to green |
me too |
Just look longer and stare at the cross. After a while there's only 1 green circle left! |
for about how long? |
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Satch
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| Posted: Fri Jul 15, 2005 2:15 am Post subject: Re: Optcal illusions |
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| sexyman wrote: | | Satch wrote: | | sexyman wrote: | | MartinaWarren wrote: | | Wow when i look at that, and stare at the cross. I only then see when moving dot, and it turns color to green |
me too |
Just look longer and stare at the cross. After a while there's only 1 green circle left! |
for about how long? |
20-30 seconds 
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sexyman
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| Posted: Fri Jul 15, 2005 2:25 am Post subject: Re: Optcal illusions |
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| Satch wrote: | | sexyman wrote: | | Satch wrote: | | sexyman wrote: | | MartinaWarren wrote: | | Wow when i look at that, and stare at the cross. I only then see when moving dot, and it turns color to green |
me too |
Just look longer and stare at the cross. After a while there's only 1 green circle left! |
for about how long? |
20-30 seconds |
 you're right they all dissapeared martina, try it again for at least 30 seconds. it's pretty cool |
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MartinaWarren
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| Posted: Fri Jul 15, 2005 2:31 am Post subject: |
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hurts my eyes
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sexyman
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| Posted: Fri Jul 15, 2005 2:35 am Post subject: |
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| MartinaWarren wrote: | | hurts my eyes |
 i kinda loss concentration for a second when i noticed that they disappeared and they came right back |
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marcus
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| Posted: Fri Jul 15, 2005 2:31 pm Post subject: |
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| sexyman wrote: | | i kinda loss concentration for a second when i noticed that they disappeared and they came right back |
I keep doing the same thing.
Wierd. On this monitor they do go green. On the other one it was more light yellow. |
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Satch
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| Posted: Fri Jul 15, 2005 2:50 pm Post subject: |
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I found an explanation on the internet:
There is something called the “negative retinal afterimage”. It becomes visible when one given hue stays on the same retinal position for several seconds (usually we would move our eyes typically 3 times per second, so this is not disadvantage in normal viewing). The afterimage builds up as that retinal location adapts to this special hue, and when looking at a neutral background the complementary colour is seen.
This is a good thing, normally, because it helps “colour constancy”, that is we see colours somewhat independent of the ambient illumination (compare the bluish glacier noon sun with a reddish tint in the evening living room by the fireside).
Ok, so the afterimage is “burnt in”, that is that retinal location is adapted. Now the magenta patch is suddenly switched to grey. Because of the adaptation, the complementary colour is now seen, which would be green for magenta, or light grey for a dark grey.
The retinal afterimage typically fades away rapidly (over a few seconds under normal conditions). But here this fade-out does not reduce the perception of the afterimage, because a new one is uncovered right after at the next location.
In addition, a Gestalt effect, here the “phi phenomenon” comes into play: the afterimage from the successive retinal locations is integrated and perceived as one single moving object, namely the green disk.
In summary, the following factors make this illusion rather compelling:
it is rather easy to steadily fixate the centre
most of the time the retinal locations are re-adapted and the afterimage is uncovered only briefly
a Gestalt effect leads to the perception of a flying green disk.
SourceJeremy L Hinton (2005-05-22, personal communication, jeremy dot hinton at bigfoot dot com)
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Satch
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| Posted: Fri Jul 15, 2005 2:53 pm Post subject: |
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This one is also cool! Do you see the black dots!? They are not really there
I found a great collection on http://www.michaelbach.de/ot/
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MartinaWarren
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| Posted: Sat Jul 16, 2005 2:37 pm Post subject: |
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I dont see black dots. Im no good at these 
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sexyman
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| Posted: Sat Jul 16, 2005 3:11 pm Post subject: |
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| Satch wrote: |
This one is also cool! Do you see the black dots!? They are not really there
I found a great collection on http://www.michaelbach.de/ot/ |
i think i might see a few gray dots if i don't focus on them |
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Satch
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| Posted: Sun Jul 17, 2005 3:10 am Post subject: |
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| MartinaWarren wrote: | | I dont see black dots. Im no good at these |
They are not exactly black, but kinda gray and a bit undefinable. They show up when you focus on a crosspoint. Although you won't see anything at that spot, but the surrounding crosspoint aren't as white as they would need to be.
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someoneoutthere
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| Posted: Mon Jul 18, 2005 10:24 am Post subject: |
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Same thing with words and colours. For example:
Green
Blue
Yellow
Or something like this.... I saw this in an e-mail.... I thought I was crazy after I read it
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Satch
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| Posted: Tue Jul 19, 2005 2:14 pm Post subject: |
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Does this add count as an optical illusion?
Now read line 1, 3, 5. 
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bennie
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| Posted: Tue Jul 19, 2005 4:20 pm Post subject: |
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| Satch wrote: | Does this add count as an optical illusion?
Now read line 1, 3, 5. |
Lol Satch odd lines only ....like the last word too |
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MartinaWarren
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| Posted: Tue Jul 19, 2005 4:29 pm Post subject: |
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Hey, That funny Satch
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sexyman
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| Posted: Tue Jul 26, 2005 6:41 pm Post subject: |
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are they spinning? 
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bennie
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| Posted: Tue Jul 26, 2005 11:23 pm Post subject: |
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Yes 
I just type what I see |
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MartinaWarren
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| Posted: Wed Jul 27, 2005 2:03 am Post subject: |
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wow, yep its spinning, but not sure if its down to the drinks tonight or not
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Satch
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| Posted: Wed Jul 27, 2005 3:23 am Post subject: |
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Scary!
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MartinaWarren
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| Posted: Wed Jul 27, 2005 3:24 am Post subject: |
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| Satch wrote: | | Scary! |
Yeah it is, it only spins slowly though. But makes you feel sick if you had a few too many while watching it
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sexyman
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| Posted: Wed Jul 27, 2005 12:40 pm Post subject: |
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| MartinaWarren wrote: | wow, yep its spinning, but not sure if its down to the drinks tonight or not
Yeah it is, it only spins slowly though. But makes you feel sick if you had a few too many while watching it |
lol i think i'm feeling sick from this and i've had nothing to drink
some of them spin clockwise and others move counter clockwise |
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marcus
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| Posted: Thu Jul 28, 2005 3:03 pm Post subject: |
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| sexyman wrote: | | some of them spin clockwise and others move counter clockwise |
Yeah thats what I see too ... wonder how that works ??  |
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Satch
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| Posted: Thu Jul 28, 2005 3:32 pm Post subject: |
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This one is also cool!
Look at the black dot and move your head backward and forward.
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marcus
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| Posted: Thu Jul 28, 2005 3:51 pm Post subject: |
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| Wow that one is really cool It works even better if i move the laptop back and forth |
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