The Ouchi Illusion DEMOs
* If you do not see the figure, you need a Java plug-in.
The Ouchi illusion
If you loosely gaze at the central disk, it appears to float apart.
Either your eye movement or the physical figure movement can cause the same effect.
Therefore, to have a more constant effect, print this picture file
on a paper and sway it slowly back and forth in a diagonal direction.
Adjust the length and the width to make more square checkers, to see how the difference
of rectangle orientation is essential. Increasing the gap helps segmentation for squares.
Spatial tuning of the illusion
First, adjust "rect. lenghth" and "rect. width" so that you see maximum
illusory motion in this figure. Then, change the disk size ("radius") to
about a half size. Does the rectangle size remain optimal? Or do you need
to make smaller rectangles to have a nice effect?
The effect of random shifting
First, adjust "bar width" to make thin black bars. I hope the illusion
does not change a lot. Then, increase "rnd shift" to randomly shift each bar.
Isn't the illusory motion weakend or abolished?
You can also test that introducing a small gap does not have a serious effect.
This reduction of illusion is closely related to the decrease of
the amplitude of the Fourier fundamental components.
Ashida (2002). Vision Research, 42, 1413-
Ashida, Kitaoka, & Sakurai (2002, ECVP).
Ashida, Kitaoka, & Sakurai, submitted to Perception.
- I have seen this page with Opera 7.2/Mozilla Firebird 0.7/IE6 on Windows,
IE5.2 on Mac OS X, and Mozilla 1.1/Mozilla Firebird 0.7 on Linux. But I
do not know how others will do.
- The gap between the image and the control area depends on the browser.
- The scroll bars do not work properly with Safari on MacOS X (seems OK with
- You cannot save the figure on your machine, which is due to the restriction
of the Java applet (otherwise I would be able to put weird files in your
machine!). Use screen capture utilities if you do need to keep the figure.
- Any suggestion? Please mail me. (but I may not have a skill or time to
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