Self-motion perception from expanding and contracting optical flows overlapped with binocular disparity

Abstract

Expanding and contracting patterns were presented on different disparity planes to investigate the role of stereo depth in vection. Experiment 1 tested the effect of stereo depth on inducing vection with expanding and contracting flows on different disparity planes. Subjects reported whether they felt forward or backward self-motion. The results clearly showed the dominance of the background flow in determining one's self-motion direction. Experiment 2 tested the effect of stereo depth on a vection direction using two expanding flows. The center of each expansion was displaced to either horizontal side. The subjects judged in which direction they were going when they felt vection. The results demonstrated that the subjects felt their heading biased toward the direction of the center of the farther expansion while feeling vection. The heading perception from the expanding flow was determined only by the background flow, not by 2-D integration of the retinal motion. The result demonstrates the importance of background flow produced by stereo depth in determining one's self-motion from an expanding/contracting motion.

Future challenges for vection research: definitions, functional significance, measures, and neural bases

“…Failures of imagination (rather than perception) could explain why it was not uncommon for subjects in such experiments to display left–right reversed heading judgments when they did not experience any vection during simulated translation (or display up–down reversed heading judgments during simulated landing – Palmisano and Gillam, 2005) 8 . Thus, Ito and Shibata (2005, p. 401) recently called for “detailed research comparing vection directions and perceived heading conducted with the same kind of stimuli.” In fact, there are already findings which suggest that performance on this sort of heading task does depend on whether the stimulus conditions are favorable for vection induction or not. For example, Grigo and Lappe (1998) reported that the accuracy of their subjects’ heading judgments changed markedly as the optic flow duration decreased from 3.2 s to only 0.4 s (Note: the latter duration would be too brief to induce any visual illusion of self-motion in a physically stationary observer).…”

Inhibition of vection by red

“…The red target was perceived as nearer and also misperceived as smaller than the green target (Gentilucci, Benuzzi, Bartolani, & Gangitano, 2001). Depth is a mediating factor of vection strength, and the farthest stimulus dominates vection direction (e.g., Ito & Shibata, 2005). It is possible that red targets (red dots) were perceived as nearer than the green targets; thus, vection was attenuated more in red dot conditions than in green ones.…”

“…This phenomenon is called vection (Fischer & Kornmuller, 1930). Several stimulus attributes are known to af-f f fect the subjective strength or direction of vection, such as depth (e.g., Ito & Shibata, 2005), visual area (e.g., Brandt, Dichgans, & Koenig, 1973), motion direction (e.g., Seno & Sato, 2009), and attention (e.g., Kitazaki & Sato, 2003). To date, color is one of the stimulus attributes in vection induction that has rarely been tested.…”

Compelling Self-Motion Through Virtual Environments Without Actual Self-Motion – Using Self-Motion Illusions ('Vection') to Improve VR User Experience

“…Already in 1975 demonstrated that the perceived self-rotation velocity (which is often used as a measure of the strength of circular vection) increases not only with the angular velocity of the visual stimulus as one might expect, but also linearly increases with the perceived distance of the moving stimulus. However, later research demonstrated that not only the absolute perceived distance, but in particular the relative depth structure and figure-ground (or object-background) separation seems critical, in that the stimulus that is perceived to be further away typically determines the occurrence, direction, and strength of vection Ito & Shibata, 2005;Nakamura, 2008;Nakamura & Shimojo, 1999;Ohmi & Howard, 1988;Ohmi et al, 1987). Several of these studies used perceptually bistable displays and demonstrated that not only physical stimulus parameters themselves, but in particular how the stimulus is perceived and interpreted at any moment in time can modulate or even determine self-motion perception.…”