

Akiyoshi's illusion pages - rangibaby
http://www.psy.ritsumei.ac.jp/~akitaoka/index-e.html

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WA
Considering the tricks of palette shifting [1] and stuff that old computer and
console games used to make computationally cheap animated backgrounds, does
anyone know if there were computer games that used optical illusions for
"computationally super-cheap animations"?

[1]
[http://www.effectgames.com/effect/article.psp.html/joe/Old_S...](http://www.effectgames.com/effect/article.psp.html/joe/Old_School_Color_Cycling_with_HTML5)

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bentcorner
I was thinking the same thing - my guess is that these illusions rely on
particular visual patterns and colors that don't lend themselves well to video
games.

One thing I'm interested in is getting video games to take advantage of eye
tracking and foveal vision for perf gains. I thought I saw a prototype
somewhere that did this but I can't dig it up at the moment...

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henrik_w
Really cool! Just to make sure there was nothing funny with the web page (not
that I thought so, but still), I printed the Rotating Snakes picture on paper.
Sure enough, they still appear to rotate, even on paper.

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pavel_lishin
You might be interested to learn that cats can also perceive this illusion:
[http://geekologie.com/2013/03/cat-can-see-spinning-
optical-i...](http://geekologie.com/2013/03/cat-can-see-spinning-optical-
illusion-tr.php)

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makeset
Ha! A cross-species evolutionary bug.

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JDGM
Absolutely superb. And I'm doing an optical illusions special with my students
this week too so this goldmine is perfectly timed. Thanks!

My favourite are the colour ones. I stare and stare at them trying to isolate
the bit that - for example - is actually grey but looks red, to see its "true"
colour. That level of concentration...not really ever seeing the grey, but
perhaps objects behind me in the room flying around Matilda-style.

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miahi
This is one of my oldest bookmarks. It's not only that the professor shows the
illusions, but he also shows his research and explains them.

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notthemessiah
The linked research only describes phenomenological characteristics of
illusions, so it doesn't strike me as an explanation. But it points to
research that does attempt to explain the peculiarities of what conditions
these illusions arise. For example, it seems to explain the effect of the
brightness of the background on these motion illusions :

 _First, an optimised stimulus can induce motion aftereffect on a stationary
sinusoidal grating, which provides evidence for the activity of the visual
motion mechanism. Second, perceived direction can be altered by background
luminance. The local mean luminance seems crucial. On the basis of these
findings, we propose that asymmetric responses of motion detectors to the
jittering luminance gradient are the source of this illusion. A gradient model
of motion detectors, which takes the image velocity as local temporal gradient
over local spatial gradient, can predict such asymmetric responses if we
assume imbalance in the positive and negative parts of temporal derivative
filters. The asymmetry then depends on the DC offset of the stimulus, which
explains the effect of the background luminance._

From <http://www.perceptionweb.com/abstract.cgi?id=v031085>

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zvrba
The "Autumn color swamp" doesn't "work" for me. Sometimes the background
appears to move, but most of the time, everything appears still..

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cosmotron
I believe this one works best when the page itself is moving (e.g. by
scrolling).

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instakill
This page is a headache waiting to happen.

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val_c
Tell me about it. I think they're incredible illustrations but my head's all
achey now!

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alan_cx
If you close you eyes, can you still see them????

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gknoy
Thankfully not, though the forks make it hard to close all the way.

