As the use of virtual and augmented reality applications becomes more common, the need to fully understand how observers perceive spatial relationships grows more critical. One of the key requirements in engineering a...
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3d shape and scene layout are often misperceived when viewing stereoscopic displays. For example, viewing from the wrong distance alters an object's perceived size and shape. It is crucial to understand the causes...
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ISBN:
(纸本)9781595939814
3d shape and scene layout are often misperceived when viewing stereoscopic displays. For example, viewing from the wrong distance alters an object's perceived size and shape. It is crucial to understand the causes of such misperceptions so one can determine the best approaches for minimizing them. The standard model of misperception is geometric. The retinal images are calculated by projecting from the stereo images to the viewer's eyes. Rays are back-projected from corresponding retinal-image points into space and the ray intersections are determined. The intersections yield the coordinates of the predicted percept. We develop the mathematics of this model. In many cases its predictions are close to what viewers perceive. There are three important cases, however, in which the model fails: 1) when the viewer's head is rotated about a vertical axis relative to the stereo display (yaw rotation);2) when the head is rotated about a forward axis (roll rotation);3) when there is a mismatch between the camera convergence and the way in which the stereo images are displayed. In these cases, most rays from corresponding retinal-image points do not intersect, so the standard model cannot provide an estimate for the 3d percept. Nonetheless, viewers in these situations have coherent 3d percepts, so the visual system must use another method to estimate 3d structure. We show that the non-intersecting rays generate vertical disparities in the retinal images that do not arise otherwise. Findings in vision science show that such disparities are crucial signals in the visual system's interpretation of stereo images. We show that a model that incorporates vertical disparities predicts the percepts associated with improper viewing of stereoscopic displays. Improving the model of misperceptions will aid the design and presentation of 3d displays.
In order to better understand how scene motion is perceived in immersive virtual environments and to provide guidelines for designing more useable systems, we measured sensitivity to scene motion for different phases ...
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ISBN:
(纸本)9781595939814
In order to better understand how scene motion is perceived in immersive virtual environments and to provide guidelines for designing more useable systems, we measured sensitivity to scene motion for different phases of quasi-sinusoidal head yaw motions. We measured and compared scene-velocity thresholds for nine subjects across three conditions: visible With head rotation (W) where the scene is presented during the center part of sinusoidal head yaws and the scene moves in the same direction the head is rotating, visible Against head rotation (A) where the scene is presented during the center part of sinusoidal head yaws and the scene moves in the opposite direction the head is rotating, and visible at the Edge of head rotation (E) where the scene is presented at the extreme of sinusoidal head yaws and the scene moves during the time that head direction changes. The W condition had a significantly higher threshold (decreased sensitivity) than both the E and A conditions. The median threshold for the W condition was 2.1 times the A condition and 1.5 times the E condition. We did not find a significant difference between the E and A conditions, although there was a trend for the A thresholds to be less than the E thresholds. An Equivalence Test showed the A and E thresholds to be statistically equivalent. Our results suggest the phase of user's head yaw should be taken into account when inserting additional scene motion into immersive virtual environments if one does not want users to perceive that motion. In particular, there is much more latitude for artificially and imperceptibly rotating a scene, as in Razzaque's redirecting walking technique, in the same direction of head yaw than against the direction of yaw. The implications for maximum end-to-end latency in a head-mounted display is that users are less likely to notice latency when beginning a head yaw (when the scene moves with the head) than when slowing down a head yaw (when the scene moves against the hea
The proceedings contain 45 papers from the 1st symposium on applied perception in graphics and visualization, APGV 2004. The topics discussed include: recalibration of rotational locomotion in immersive virtual enviro...
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ISBN:
(纸本)1581139144
The proceedings contain 45 papers from the 1st symposium on applied perception in graphics and visualization, APGV 2004. The topics discussed include: recalibration of rotational locomotion in immersive virtual environments;distance perception in real and virtual environments;vision realistic rendering: simulation of the scanned foveal image from wavefront data on human subjects;enhancing perceived depth in images via artistic matting;selective rendering of task related scenes;effective color coding of menu design for movie genres;observations of visual and audio coaching methods in a virtual laparoscopic training environment;selective rendering of task related sceness and causes of depth perception errors.
This poster reviews the psychophysics literature on threshold contrast and incorporates the results into a technique for measuring display visibility. This work is validated, and subsequently studied in the context of...
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ISBN:
(纸本)9781595936707
This poster reviews the psychophysics literature on threshold contrast and incorporates the results into a technique for measuring display visibility. This work is validated, and subsequently studied in the context of air traffic control displays.
Uncertainty constitutes a major obstacle to effective decision making. This work presents perceptual and cognitive principles from Tufte, Chambers and Bertin as well as results from user experiments for the theoretica...
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An experiment to determine factors that influence the perceived sex of virtual characters was conducted. Four different model types were used: highly realistic male and female models, an androgynous character, and a p...
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