Purchase this article with an account.
R.L. Woods, J.C. Shieh, L. Bobrow, A. Vora, J. Barabas, R.B. Goldstein, E. Peli; Perceived Collision With an Obstacle in a Virtual Environment . Invest. Ophthalmol. Vis. Sci. 2003;44(13):4321.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: When you traverse a real or a virtual environment, you make decisions about potential collisions with obstacles. Collision avoidance is based on some internal perception of a safe passing distance, that might be based on physical characteristics. Methods: Twenty normally-sighted subjects walked on a treadmill at their own pace while viewing a computer-simulated scene projected on a large screen. The subject walked on a pre-determined zig-zag path down a long corridor that had shop fronts for walls. Obstacles were square pillars wrapped with a picture of an adult (70cm wide) or a child (30cm wide), that appeared for one second, either 5m or 15m from the subject and with various passing distances (offsets). Yes-no responses about the potential for a collision were analyzed using a signal detection approach based on the distance between the subject’s center and the obstacle perimeter (collision envelope). Various physical measures of subjects were made (e.g. width, stride length). Results: Subject performance was more efficient at 5m than at 15m. The collision envelope was larger for 15m (62±23cm) than at 5m (41±19cm) obstacles. Many subjects had difficulty accurately determining collisions with 15m obstacles directly in their path. When provided with heading information, task performance improved substantially at 15m. The collision envelope was not predicted by obstacle size or by any subject physical measure. However, when some subjects wore "wings" to extend their width (±37cm), their collision envelopes became larger (36 v 67cm). Conclusions: Previous collision studies have tended to consider their subjects as points moving through the environment. While that approach can answer some questions about behavior, the perception of your size and a safe passing distance, the collision envelope, is an important characteristic that is expected to govern behavior. Since we could not predict the collision envelope from physical characteristics, some cognitive factor appears to determine the collision envelope.
This PDF is available to Subscribers Only