Ambiguous motion perception occurs when an extended one-dimensional (1-D) object such as a luminance border, a line or a grating, moving behind an aperture is viewed. This ambiguity is due to the uncertainty of the veridical velocity of the moving 1-D object whose apparent velocity may vary with the change in the shape of the aperture in view. This interesting phenomenon has come to be known as the aperture problem. / In this research project, human motion perception was studied psychophysically where the geometry, number of stimulus apertures and number of moving 1-D grating components with different orientations were varied. Monocular and dichoptic viewing conditions were used to study human binocular motion processing as well. In all cases, multi-stable subjective motion percepts were observed. Specifically, when a moving 1-D stimulus was viewed behind a rectangular aperture, a unique, global, coherent motion percept or a illusory "barber pole motion" percept could be seen. An unexpected compound illusory barber pole motion percept was observed in addition to the perceived coherent motion when a cross-shaped aperture was used. The coherent motion percept and the illusory barber pole motion percepts were seen to alternate chaotically over time, with different amounts of coherent motion and component motion seen as the physical parameters of the stimuli were varied. / Multi-stable motion percepts which required binocular integration of local motion information were also observed. For example, during binocular fusion of two dichoptically viewed moving orthogonal 1-D gratings, observers could see a coherently moving unitary 2-D plaid. In addition, global coherent motion percepts also occurred with stimulation of non-overlapping visual fields stimulated separately in the two eyes. These results suggested the presence of two mechanisms, one cooperative and one competitive, operating interactively in the human visual motion channel. Furthermore, the results also support the notion that human coherent motion perception is mediately by close coupling between several putative visual channels. / Source: Dissertation Abstracts International, Volume: 52-04, Section: B, page: 2346. / Major Professor: Mark A. Berkley. / Thesis (Ph.D.)--The Florida State University, 1991.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_76392 |
| Contributors | Ho, Wing-Lun Alan., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 139 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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