Maybe I should mention that the effect seemed either very diminished or absent entirely when I kept my head still and just shifted my gaze around the aforementioned circle. —Dan
On May 26, 2017, at 12:37 PM, Allan Wechsler <acwacw@gmail.com> wrote:
I can see what Dan is talking about. That image is complicated, though. It's very hard to say what aspect is eliciting the effect. For me the effect is pronounced at first, and then diminishes. It would be good to come up with more abstract images that also elicit the effect.
On Fri, May 26, 2017 at 3:19 PM, Adam P. Goucher <apgoucher@gmx.com> wrote:
Can reproduce Dan's illusion; unfortunately, cannot remember the sixties ... APG
Sent: Friday, May 26, 2017 at 5:21 PM From: "Fred Lunnon" <fred.lunnon@gmail.com> To: math-fun <math-fun@mailman.xmission.com> Subject: Re: [math-fun] Koosh illusion
Couldn't reproduce Dan's illusion. But I _can_ remember the sixties ... WFL
On 5/26/17, Dan Asimov <dasimov@earthlink.net> wrote:
I was looking at this photo of a Koosh ball:
https://en.wikipedia.org/wiki/Koosh_ball#/media/File:KOOSH.png <https://en.wikipedia.org/wiki/Koosh_ball#/media/File:KOOSH.png>
from about a foot away from my 27" computer screen.
Closing one eye, I moved my head in a very small circle while remaining a foot away: just a little to the right, then above, then to the left, then below (rinse, lather, repeat) of dead center on the Koosh ball — and while doing so, have my gaze cycle around a circle on the screen centered at the center of the ball's image. (The screen circle is roughly the nearest screen point to my head at a given moment.)
The result: a persuasive illusion that the image is changing slightly due to parallax, that is, depending on the varying positions of the eye as it moves in a circle.
Question: Is this a known illusion? Does it generalize beyond Koosh balls?
—Dan _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun