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Rank: Super Veteran Joined: 23 Dec 2004 Posts: 2368

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?

Rank: Super Veteran Joined: 23 Dec 2004 Posts: 2043

Nice one Satch !!! Cool

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:

Official Model Joined: 22 Dec 2004 Posts: 5031

Rank: Super Veteran Joined: 25 Dec 2004 Posts: 1915

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 Confused

Rank: Mr. Fabulous Joined: 19 Jun 2005 Posts: 372

Rank: Super Veteran Joined: 23 Dec 2004 Posts: 2368

Rank: Mr. Fabulous Joined: 19 Jun 2005 Posts: 372

Rank: Super Veteran Joined: 23 Dec 2004 Posts: 2368

Rank: Mr. Fabulous Joined: 19 Jun 2005 Posts: 372

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hurts my eyes Confused

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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)

Rank: Super Veteran Joined: 23 Dec 2004 Posts: 2368

This one is also cool! Do you see the black dots!? They are not really there Confused

I found a great collection on http://www.michaelbach.de/ot/

Official Model Joined: 22 Dec 2004 Posts: 5031

I dont see black dots. Im no good at these Rolling Eyes

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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 Shocked