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. 2009 Jun 1;18(3):365-378.
doi: 10.1142/S0218213009000184.

DEVELOPMENT AND EVALUATION OF VISION MULTIPLEXING DEVICES FOR VISION IMPAIRMENTS

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Free PMC article

DEVELOPMENT AND EVALUATION OF VISION MULTIPLEXING DEVICES FOR VISION IMPAIRMENTS

Eli Peli et al. Int J Artif Intell Tools. .
Free PMC article

Abstract

We have proposed a novel concept of vision multiplexing for the visually impaired - superimposing contour images over their natural view of a scene or over original images presented on a TV screen. We have implemented the concept using an optical see-through head mounted display to provide either visual field expansion to patients with peripheral field loss or vision enhancement to patients with central vision loss. We have also implemented the concept in a video player with dynamic magnification for patients with central vision loss. Results of initial testing in the lab and on the street are promising.

Figures

Fig. 1
Fig. 1
Simulation of the appearance of spatial vision multiplexing. (a) A street-crossing scene as it might appear to a patient with tunnel vision using the augmented vision system that provides an expanded VF. The woman’s head is seen in full resolution through the display as well as in the superimposed minified contour image. The contour (edge-image) provides a wide field of view enabling detection of the pedestrian (on the left) crossing in the other direction (a potential collision that would not be visible without the display). (b) Illustration of the effect of enhancement by superimposing 1:1 scaled edge images of the scene over the natural view, an application that may be beneficial for patients with central vision loss.
Fig. 2
Fig. 2
The current generation of augmented vision HMD field expander for patients with tunnel vision. The wide-angle image captured by the video camera is processed by the controller to provide edge contour images of the scene. The edge images are displayed on the see-through display providing an expanded view. Once an object is detected from the minified edge images, it can be examined with full resolution and color through the transparent display.
Figure 3
Figure 3
The visual search task. Targets were presented outside subjects’ visual fields. The minified target contour (edge) images seen in the HMD field expander provided cues for both the direction and eccentricity of targets. Auditory direction cues were provided by buzzers around the screen.
Fig. 4
Fig. 4
(a) Visual search time of the three subjects in the larger area search. Auditory cues and contour (edge-image) cues from the HMD field expander significantly reduced search time for all subjects. (b) Mean directness of the 9 subjects in the smaller area search. In both studies, directness with either auditory or contour cues was better than without cues.
Fig. 4
Fig. 4
(a) Visual search time of the three subjects in the larger area search. Auditory cues and contour (edge-image) cues from the HMD field expander significantly reduced search time for all subjects. (b) Mean directness of the 9 subjects in the smaller area search. In both studies, directness with either auditory or contour cues was better than without cues.
Fig. 5
Fig. 5
An augmented vision HMD device increased the PSPD only on the camera side, but had no effect on the display side. A PSPD asymmetry appeared in both with- and without-device conditions.
Fig. 6
Fig. 6
Median ratings for various aspects of night vision device performance based on experiences during the indoor and outdoor assessments (1= Very Poor; 2= Poor; 3= Fair; 4=Good; 5= Very Good). The first prototype of the augmented vision HMD field expander (LV-3) was highly rated (score of = 4) for comfort and weight. The comparison opaque HMD night vision device (M-V) was highly rated for ease of use and image quality. Error bars represent inter-quartile range.
Fig. 7
Fig. 7
An illustration of consistent registration performance across a wide range of distances for the on-axis HMD system. Five identical white bar targets were placed at 3, 4, 5, 6, and 7 feet from the HMD system. The registration was purposely shifted down to provide a simultaneously clear view of the real objects and their virtual edge images. This picture was captured with a digital camera aimed through the HMD. Five identical gauges depicted next to the white bars show that the registration was consistent from 3′ to 7′. Note, however, that the edges are dimmer than the white target in this implementation.
Fig. 8
Fig. 8
(a) A full frame of a video. (b) A portion of the image enlarged around the center of the frame. (c) The player holding the ball may be the most relevant portion of the scene. (d) Image of another frame is enlarged around the ball player with the edge image of the full frame superimposed.

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