An ideal head-mounted display (HMD) is a device that provides a visual experience indistinguishable from that given by the naked eye. Such an HMD must display images with spatial resolution surpassing that of the human visual system. However, excessively high spatial resolution is resource-wasting and inefficient. To optimize this balance, we evaluated the spatial resolution characteristics of the human visual system in the peripheral visual area. Our experiment was performed based on a head-centered coordinate system, acknowledging that users can move their eyes freely within the HMD housing fixed on the user’s head. We measured threshold eccentricities where low-pass filtered noise patterns could be distinguished from intact noise patterns, manipulating cut-off spatial frequencies between one to eight cycles per degree. The results revealed clear asymmetries between the temporal and nasal, as well as between the upper and lower visual fields. In the temporal and lower fields, lower cut-off spatial frequencies resulted in higher eccentricity thresholds. Notably, the smaller impact of spatial frequencies in the nasal and upper visual fields is likely due to visual obstruction by facial structures, such as the nose. Our results can serve as a standard for pixel arrangement design in an ideal HMD.

This article discusses the depth range which automultiscopic 3D (A3D) displays should reproduce for ensuring an adequate perceptual quality of substantially deep scenes. These displays usually need sufficient depth reconstruction capabilities covering the whole scene depth, but due to the inherent hardware restriction of these displays this is often difficult, particularly for showing deep scenes. Previous studies have addressed this limitation by introducing depth compression that contracts the scene depth into a smaller depth range by modifying the scene geometry, assuming that the scenes were represented as CG data. The previous results showed that reconstructing only a physical depth of 1 m is needed to show scenes with much deeper depth and without large perceptual quality degradation. However, reconstructing a depth of 1 m is still challenging for actual A3D displays. In this study, focusing on a personal viewing situation, we introduce a dynamic depth compression that combines viewpoint tracking with the previous approach and examines the extent to which scene depths can be compressed while keeping the original perceptual quality. Taking into account the viewer's viewpoint movements, which were considered a cause of unnaturalness in the previous approach, we performed an experiment with an A3D display simulator and found that a depth of just 10 cm was sufficient for showing deep scenes without inducing a feeling of unnaturalness. Next, we investigated whether the simulation results were valid even on a real A3D display and found that the dynamic approach induced better perceptual quality than the static one even on the real A3D display and that it had a depth enhancing effect without any hardware updates. These results suggest that providing a physical depth of 10 cm on personalized A3D displays is general enough for showing any deeper 3D scenes with appealing subjective quality.

This paper describes how the screen size of 3D displays affect the subjective impressions of 3D-visualized content. The key requirement for 3D displays is the presentation of depth cues comprising binocular disparities and/or motion parallax; however, the development of displays and production of content that include these cues leads to an increase in costs. Given the variety of screen sizes, it is expected that 3D characteristics are experienced differently by viewers depending on the screen size. We asked 48 participants to evaluate the 3D experience when using three different-sized stereoscopic displays (11.5, 55, and 200 inches) with head trackers. The participants were asked to score presented stimuli on 20 opposite-term pairs based on the semantic differential method after viewing each of six stimuli. Using factor analysis, we extracted three principal factors: power , related to strong three-dimensionality, real, etc.; visibility , related to stable, natural, etc.; and space , related to agile, open, etc., which had proportions of variances of 0.317, 0.277, and 0.251, respectively; their cumulation was 0.844. We confirmed that the three different-sized displays did not produce the same subjective impressions of the 3D characteristics. In particular, on the small-sized display, we found larger effects on power and space impressions from motion parallax (η 2 = 0.133 and 0.161, respectively) than for the other two sizes. We found degradation of the visibility impressions from binocular disparities, which might be caused by artifacts from stereoscopy. The effects of 3D viewing on subjective impression depends on the display size, and small-sized displays offer the largest benefits by adding 3D characteristics to 2D visualization.

Perception of color varies markedly between individuals because of differential expression of photopigments in retinal cones. However, it has been difficult to quantify the individual cognitive variation in colored scene and to predict its complex impacts on the behaviors. We developed a method for quantifying and visualizing information loss and gain resulting from individual differences in spectral sensitivity based on visual salience. We first modeled the visual salience for color-deficient observers, and found that the predicted losses and gains in local image salience derived from normal and color-blind models were correlated with the subjective judgment of image saliency in psychophysical experiments, i.e., saliency loss predicted reduced image preference in color-deficient observers. Moreover,saliency-guided image manipulations sufficiently compensated for individual differences in saliency. This visual saliency approach allows for quantification of information extracted from complex visual scenes and can be used as an image compensation to enhance visual accessibility by color-deficient individuals.