Optic-flow and egocentric-direction strategies in walking: Central vs peripheral visual field
| Autor: | Lei Hao, John C. Hicks, Kathleen A. Turano, Dylan Yu |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Adult
Offset (computer science) Computer science media_common.quotation_subject Allocentric Motion Perception Vision Disorders Optical flow Walking Vision impairment Goal-directed walking Memory Memory-guided walking Perception Humans Computer vision Motion perception Spatial representation Aged media_common Mobility Communication Landmark Landmarks business.industry Optic flow Vision Tests Middle Aged Sensory Systems Visual field Ophthalmology Visual field loss Head Movements Peripheral vision Peripheral visual field loss Artificial intelligence Visual Fields business Goals Photic Stimulation Psychomotor Performance |
| Zdroj: | Vision Research. 45:3117-3132 |
| ISSN: | 0042-6989 |
| DOI: | 10.1016/j.visres.2005.06.017 |
| Popis: | The impact of a central or peripheral visual field loss on the vision strategy used to guide walking was determined by measuring walking paths of visually impaired participants. An immersive virtual environment was used to dissociate the expected paths of the optic-flow and egocentric-direction strategies by offsetting the walker's point of view from the actual direction of walking. Environments consisted of a goal within a forest, the goal alone, or the forest alone following a brief presentation of the goal. The first two environments allowed an evaluation of the visual information used in a goal-directed task whereas the third environment investigated the information used in a memory-guided task. Participants had either a central (CFL) or peripheral visual field loss (PFL) or were fully sighted (FS). Results showed that, for the goal-directed task, the CFL group was less influenced by optic flow than was an age-matched FS group. Optic flow decreased heading error by only 1.3 degrees (16%) in the CFL group compared to 3.6 degrees (42%) in the FS group. The PFL group showed an optic-flow influence (2.4 degrees or 26%) comparable to an older, age-matched FS group (2.9 degrees or 31%). For the memory-guided task, all but the PFL group had heading errors comparable to those obtained in the goal-alone scene, demonstrating the ability to use an egocentric-direction strategy with a stored representation of either the goal's position or an offset relative to a landmark instead of a visible goal. The paths of the PFL group veered significantly from the predicted paths of both the optic-flow and egocentric-direction strategies. The findings of this study suggest that central vision is important for using optic flow to guide walking, whereas peripheral vision is important for establishing and/or updating an accurate representation of spatial structure for navigation. |
| Databáze: | OpenAIRE |
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