[visionlist] geometrically ambiguous images
Raymond van Ee
r.vanee at phys.uu.nl
Tue Feb 14 09:42:50 GMT 2006
Although there are stimuli that evoke tristable perception, to my knowledge there are no true 3D geometrical illusions that are tristable.
Perhaps you are interested in a JOV paper (http://journalofvision.org/2/9/2/) where you can find a (limited) historical overview on a geometrical illusion in binocular 3D surface perception (dating back to forgotten work of Wheatstone). The described "slant rivalry" is an unique geometrical illusion in that it only exists because of our ability to have binocular vision (unlike e.g. for the Necker cube which can be experienced monocularly). In fact the perceived slant in "slant rivalry" ought to be infinitely unstable as the brain can come up with any combination of weighting factors to process the described depth signals. Yet, observers have apparently two (bi-) limited sets from which they draw their weighting factors.
Well, I hope this is of interest to you. If you wish to receive more info, don't hesitate to let me know. I am interested in your work on the "analogy for certain cases in philosophy" and its mutation into a philosophical "-ism", especially for infinite-(in)stability that converges to bi-stable streams.
All the very best with your research into this fascinating issue,
Raymond van Ee
Assoc. Prof. Physics, Utrecht University
>I wonder if you may be able to help me with a brief query. I am a PhD
>student in the History and Philosophy of Science Department at Cambridge
>University. I have recently become interested in the Necker Cube as it
>provides an interesting analogy for certain cases in philosophy. I am
>trying to find out two things with respect to the Necker Cube:
>(1) are there any geometrical images which are TRIPLY ambiguous in the way
>that the Necker Cube is doubly ambiguous, where the transitions between
>ambiguities are obvious, regular, and spontaneous (i.e. not dependent upon
>(2) is there a name (or names) for the CLASS of geometrically ambiguous
>images which includes Necker Cubes as well as some other nameless
>geometrically ambiguous forms I have encountered in the past? If there is
>such a term for this class, I would be interested in finding it out as I
>may be able to mutate it into a philosophical "-ism" which would express
>the sort of position I am developing in my thesis.
>Thanks for taking the time to read this. I hope you might be able to help!
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