June 2006
Volume 6, Issue 6
Free
Vision Sciences Society Annual Meeting Abstract  |   June 2006
Is obstacle avoidance controlled by perceived distance or time-to-contact?
Author Affiliations
  • Hugo Bruggeman
    Dept. of Cognitive & Linguistic Sciences, Brown University
  • Daniel B. Rothman
    Dept. of Cognitive & Linguistic Sciences, Brown University
  • William H. Warren
    Dept. of Cognitive & Linguistic Sciences, Brown University
Journal of Vision June 2006, Vol.6, 136. doi:10.1167/6.6.136
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Hugo Bruggeman, Daniel B. Rothman, William H. Warren; Is obstacle avoidance controlled by perceived distance or time-to-contact?. Journal of Vision 2006;6(6):136. doi: 10.1167/6.6.136.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Question: Do steering adjustments depend on the perceived distance or time-to-contact with an obstacle? Our locomotor dynamics model (Fajen & Warren, JEP:HPP, 2003) currently assumes distance as an input variable but could alternatively use time-to-contact, specified by the relative rate of optical expansion. To dissociate these hypotheses we independently vary physical walking speed and the visual gain in a virtual environment. The manipulations produce similar optical speeds but only the physical walking speed affects the inertial properties of the body.

Design: The experiment is performed in an ambulatory virtual environment (10m x10m) with a head-mounted display (60° H x 40° V) and a sonic/inertial tracking system (50–70ms latency). Participants are instructed to walk at three speeds (2/3, 1 or 3/2 of preferred walking speed). These are partially crossed with three visual gains (2/3, 1, 3/2), such that the optical motion in the display is slower, matched, or faster than the actual walking speed. Participants walk to a stationary goal (6m straight ahead) around an obstacle whose position varies across trials (initial distance of 3 or 5m, 3° to the left or right of the straight path).

Results: Using distance as the control variable, the model predicts that the agent will turn later as speed increases, whereas using time-to-contact it predicts the reverse. The dependence of steering behavior on the body's inertial properties can also be assessed. Model predictions are evaluated against the human data to empirically determine whether human obstacle avoidance is controlled by distance or time-to-contact.

Bruggeman, H. Rothman, D. B. Warren, W. H. (2006). Is obstacle avoidance controlled by perceived distance or time-to-contact? [Abstract]. Journal of Vision, 6(6):136, 136a, http://journalofvision.org/6/6/136/, doi:10.1167/6.6.136. [CrossRef]
Footnotes
 NIH EY10923
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×