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Proceedings Paper

Collision judgment when viewing minified images through a HMD visual field expander
Author(s): Gang Luo; Lee Lichtenstein; Eli Peli
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Paper Abstract

Purpose: Patients with tunnel vision have great difficulties in mobility. We have developed an augmented vision head mounted device, which can provide patients 5x expanded field by superimposing minified edge images of a wider field captured by a miniature video camera over the natural view seen through the display. In the minified display, objects appear closer to the heading direction than they really are. This might cause users to overestimate collision risks, and therefore to perform unnecessary obstacle-avoidance maneuvers. A study was conducted in a virtual environment to test the impact of minified view on collision judgment. Methods: Simulated scenes were presented to subjects as if they were walking in a shopping mall corridor. Subjects reported whether they would make any contact with stationary obstacles that appeared at variable distances from their walking path. Perceived safe passing distance (PSPD) was calculated by finding the transition point from reports of yes to no. Decision uncertainty was quantified by the sharpness of the transition. Collision envelope (CE) size was calculated by summing up PSPD for left and right sides. Ten normally sighted subjects were tested (1) when not using the device and with one eye patched, and (2) when the see-through view of device was blocked and only minified images were visible. Results: The use of the 5x minification device caused only an 18% increase of CE (13cm, p=0.048). Significant impact of the device on judgment uncertainty was not found (p=0.089). Conclusion: Minification had only a small impact on collision judgment. This supports the use of such a minifying device as an effective field expander for patients with tunnel vision.

Paper Details

Date Published: 6 March 2007
PDF: 8 pages
Proc. SPIE 6426, Ophthalmic Technologies XVII, 64261Z (6 March 2007); doi: 10.1117/12.723955
Show Author Affiliations
Gang Luo, Harvard Medical School (United States)
Lee Lichtenstein, Harvard Medical School (United States)
Eli Peli, Harvard Medical School (United States)

Published in SPIE Proceedings Vol. 6426:
Ophthalmic Technologies XVII
Bruce E. Stuck; Fabrice Manns; Per G. Söderberg; Michael Belkin M.D.; Arthur Ho, Editor(s)

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