Computer Graphics and Visualization Lab
Department of Computer Science at Purdue University

Study of Shape Perception Using Volumetric 3D Images

We have conducted two psychophysical experiments that compare shape perception between a volumetric 3D display and an LCD display. Our 3D display is a device that renders a 3D image by displaying, in rapid succession, radial slices through the scene on a rotating screen. The image is contained in a glass globe and can be viewed from virtually any direction.
Experiment 1
In one experiment objects with varying complexity were used as stimuli. On each trial an object or a distorted version is shown at an arbitrary orientation. The subject’s task is to decide whether the object is distorted or not, under several viewing conditions (monocular/binocular, with/without motion parallax, and near/far). The subject’s performance is measured by the detectability d', a conventional dependent variable in signal detection experiments. Highest d’ values were measured for the 3D display when the subject is allowed to walk around the display.

Experiment setup. The lights were dimmed during the actual experiment.

Objects used as stimuli.

Photographs of the 3D images used as stimuli.
Experiment 2
In a second experiment we tested the perception of 3D surfaces that have been rendered by a set of lines drawn on the surface. Each surface is rendered as a family of curves which are in the simplest case the intersections with a family of parallel planes. On each trial, a surface or its “distorted” version is shown in this way, in an arbitrary orientation on an LCD screen or in a volumetric 3D display. The subject’s task is to decide whether two sequentially presented surfaces are identical or not. The work investigates the question whether a surface rendered with planar and geodesic curves is easier to recognize than one where the curves are not planar or not geodesic. Our results show that the effect of the type of the contour is very similar in both monoscopic and stereoscopic viewing, but with a substantially higher performance in the stereoscopic case.

Experimental setup.

Sample Gaussians used as stimuli.

Photographs of 3D images used as stimuli.

projects/perception.txt · Last modified: 2008/09/15 21:28 by rosenpa
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