We found that 30 % of non-stereoanomalous observers, aged 19 to 25 years old, did not use disparity in making depth judgments in 3D-graphic environments. However, several questionnaires indicate that the use of disparity can be learned unconsciously, suggesting that poor stereopsis can be improved by appropriate training procedures.

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We investigated the individual differences in the use of binocular disparity and proposed a method for improving stereopsis in observers who do not perceive depth from disparity in 3D-graphic environments. In Experiment 1, non-stereoanomalous observers, aged 19-25 years, were asked to roughly evaluate the depth of 3D-graphcial stimuli containing binocular disparity and shading. The results of Experiment 1 showed 30% of the observers were pseudo-stereoanomaly who perceived depth only from shading. In Experiment 2, 60% of the pseudo-stereoanomalous observers were able to use disparity when they had to assess the depth concretely. In Experiment 3, all of the observers who participated in Experiment 2 learned to use the disparity information when retasked with roughly estimating again. These results suggest that quite a few people have difficulty in experiencing rich depth perception in current 3D-graphic environments. However, appropriate training procedures would improve their use of disparity information over the long term.

We find that pseudo-stereoanomalous observers, who did not use disparity information for depth judgments in 3D-graphics environments although they were not stereoanomalous, tended to be younger (21.4%, 17-24 years old) than young-middle age (11.4%, 25-39 years old). Approximately 80% of older (50-83 years old) were also pseudo-stereoanomalous observers.Author Keywords depth perception; stereopsis; aging; 3D-graphics environments; binocular disparity; pictorial depth cue. Objective and BackgroundRecently, 3D-graphics environments, such as movie theaters, home televisions, and video games, are rapidly gaining in popularity, and people of all ages have a lot of chances to view 3D contents. Although binocular disparity plays an important role in the perception of depth, it is well known that there are large individual differences in the availability of binocular disparity. For example, many elderly adults have defective stereopsis because of degraded performance of senescent cerebral or retinal cells [1]. In addition, over 10% of observers, who do not have any physically visual disabilities, perceive virtually no depth depending on the disparity information [2]-[3], i.e. they are stereoanomalous observers.More interestingly, quite a few people cannot fully process information from binocular disparity in a specific 3D-graphic environment even though they can discriminate small levels of disparity (e.g., 4′) in a simple stereoscopic test. Fujisaki et al. [4] examined the individual differences in use of disparity information in the prevailing 3D-graphics environments that were expected to give observers rich depth perception through a combination of binocular disparity and monocular pictorial cues [5]. Using simple 3D-graphic stimuli containing binocular disparity and shading, one of the most effective pictorial depth cues [6]- [7], Fujisaki et al. demonstrated that 30% of young observers, aged 19 to 25 years, relied only on information from shading, rather than from disparity, to perceive the depth of the 3D stimuli even though they were not stereoanomalous. We call them pseudo-stereoanomalous observers.Given that the individual ability of depth perception is dependent on age [1], it is likely that the ratio of the pseudo-stereoanomalous observers varies with age. In this study, we investigated the relationship between age and the rate of pseudo-stereoanomalous observers. 151 individuals with ages ranging from 17 to 85 years observed a simple 3D-graphic stimuli containing binocular disparity and shading as depth cues, which was used in Fujisaki et al. [4], and evaluated the subjective depth of the 3D stimulus. Results Experimental methods Apparatus and StimuliFull-HD (i.e., WUXGA 1920 × 1200) 24-inch stereoscopic liquidcrystal displays with 60 Hz refresh rate (True3Di SDM-240, Redrover) remained stationary at 930 mm from the observer (approximately three times the height of the screen, which is standard viewing distance for high resolution television). Before the experiment, the stereoscopic vision of all ob...

Some stereoblind observers do not perceive depth of 3D stimuli that depends on binocular disparity. These individuals, who have no disabilities, comprise over 5% of the general population. In addition, 17–30% of nonstereoblind young and young–middle people do not use disparity information in certain 3D environments, a phenomenon known as pseudo‐stereoblindness. This study aimed to investigate the relationship between aging and the proportion of pseudo‐stereoblindness in the general population. In an experiment, 134 nonstereoblind participants, ranging in age from 17 to 83 years, judged subjective depth of 3D stimuli containing binocular disparity and pictorial depth cues. Results showed that the proportion of pseudo‐stereoblindness among young (17–24 years old) and young–middle aged observers (25–39 years old) was 29%, in both cases. However, the proportion of pseudo‐stereoblind observers increased in older populations: 65% and 82% in the middle (40–54 years old) and senior (55–83 years old) age groups, respectively. These results suggest that a number of people, especially in elderly populations, have trouble perceiving depth from binocular disparity in 3D graphic contents despite their essential ability to use disparity information.