Managing level of detail through head-tracked peripheral degradation

Proceedings of the ACM symposium on Virtual reality software and technology - VRST '97 (1997), pp. 59-63, doi: 10.1145/261135.261148
Experiments
Tasks
Findings

How does a high-detail central area inset in in peripherally degraded displays affect search performance?

Variables and Constants

Independent Variables
Constants

The authors used the Flight Helmet in a monoscopic, biocular mode. Maximum frame rate was 30.

System Info

Displays
None
Input Hardware
  • virtual research flight helmet - the flight helmet mounts two color lcd displays on the user’s head, each with vertical field of view of 58.4 degrees, and a horizontal fgv of 75.3 degrees, each lcd contains an array of 208 x 139 color triads.
  • polhemus isotrak ii tracker - for head tracking
  • mouse - 3 buttons, shaped like a pistol grip.
Software
None

Assuming the hardware is extremely similar in previous studies, here are the specifications for the machine runnig hte display: The HMD was powered by a Silicon Graphics Onyx Reality Engine II. Computer: Silicon Graphics Reality Engine 2 (Onyx) Processor: 184MHz RAM: 512 MB Cache: 4MB Drive: 4GB hard disk Graphics: Reality Engine 2

Participant Info

Eight graduate students participated in the experiment. All reported normal vision, none wore eyeglasses.

Total # Age Range Gender Balance
8 -

During each trial, subjects would search through five randomly located, identically sized objects for a target object. Most objects were textured with identical images of a smiling human face. The single, target object was textured with the same face, with the mouth closed. The participant would press a button, and the target object would either move or disappear. The participant would indicate whether the target was there or not.

Interaction and Environment

Interface

There was no other interaction besides visual scanning of the area. The participant responded by pressing one of two buttons.

The virtual experimental environment consisted of a floor, indicated by a grid of white lines on black. The background above the floor was also black.

Dimensionality Scale Density Visual Realism
3D Small Low Low
Metrics

  • time - search time when the target was present
  • accuracy - accuracy in having the target into their view, when the target was present
  1. There was a significant inverse effect of horizontal level of detail inset extent on time for a visual search task.

    Wider horizontal level-of-detail insets lead to shorter search times for target finding tasks.

    Specificity: Somewhat specific
    This applied to comparing 10 degrees with 30 or 40 degrees.

  2. There was a significant inverse effect of vertical level of detail inset extent on time for a visual search task.

    Taller vertical level-of-detail insets lead to shorter search times for target finding tasks.

    Specificity: Somewhat specific
    This applied to comparing 10 degrees with 30 or 40 degrees.