Structure-From-Motion cylinder
| K. Hol, A. Koene & R. van Ee (2003). Attention-biased multi-stable surface perception in three-dimensional structure-from-motion. Journal of Vision, 3, 486-498. |  |
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SFM stimuli have traditionally been taken to evoke bistable percepts, say percepts of a horizontal transparent cylinder spinning either clockwise or counterclockwise when viewed from the top. We noticed that subjects can also perceive two transparent half-cylinders either convex or (to a lesser extent) concave spinning one in front of the other. We first noticed these, to our knowledge unreported, four variations of the percept evoked by the traditional cylinder SFM stimulus at a local conference. We thank Prof.Dr. A.H. Wertheim and Prof.Dr. J.J. Koenderink, who were in the audience, for bringing the different percepts to our attention. After their comment, almost all observers in the audience were able to see at least the transparent cylinders and the two-fronts percepts, and some of them were able to perceive also the two-backs percept. The two novel percepts can be easily seen by color-coding the dot patterns (motion directions). We thank Pieter Schiphorst, our compuer wizard, for creating the html-file. |