Despite an increased need for three-dimensional (3-D) functionality in curved displays, comparisons pertinent to human factors between curved and flat panel 3-D displays have rarely been tested. This study compared stereoscopic 3-D viewing experiences induced by a curved display with those of a flat panel display by evaluating subjective and objective measures. Twenty-four participants took part in the experiments and viewed 3-D content with two different displays (flat and curved 3-D display) within a counterbalanced and within-subject design. For the 30-min viewing condition, a paired t-test showed significantly reduced P300 amplitudes, which were caused by engagement rather than cognitive fatigue, in the curved 3-D viewing condition compared to the flat 3-D viewing condition at P3 and P4. No significant differences in P300 amplitudes were observed for 60-min viewing. Subjective ratings of realness and engagement were also significantly higher in the curved 3-D viewing condition than in the flat 3-D viewing condition for 30-min viewing. Our findings support that curved 3-D displays can be effective for enhancing engagement among viewers based on specific viewing times and environments.
As advanced display technology has been developed, much attention has been given to flexible panels. On top of that, with the momentum of the 3D era, stereoscopic 3D technique has been combined with the curved displays. However, despite the increased needs for 3D function in the curved displays, comparisons between curved and flat panel displays with 3D views have rarely been tested. Most of the previous studies have investigated their basic ergonomic aspects such as viewing posture and distance with only 2D views. It has generally been known that curved displays are more effective in enhancing involvement in specific content stories because field of views and distance from the eyes of viewers to both edges of the screen are more natural in curved displays than in flat panel ones. For flat panel displays, ocular torsions may occur when viewers try to move their eyes from the center to the edges of the screen to continuously capture rapidly moving 3D objects. This is due in part to differences in viewing distances from the center of the screen to eyes of viewers and from the edges of the screen to the eyes. Thus, this study compared S3D viewing experiences induced by a curved display with those of a flat panel display by evaluating significant subjective and objective measures.
To avoid the vergence-accommodation mismatch and provide a strong sense of presence to users, we applied a prism array-based display when presenting three-dimensional (3-D) objects. Emotional pictures were used as visual stimuli to increase the signal-to-noise ratios of steady-state visually evoked potentials (SSVEPs) because involuntarily motivated selective attention by affective mechanisms can enhance SSVEP amplitudes, thus producing increased interaction efficiency. Ten male and nine female participants voluntarily participated in our experiments. Participants were asked to control objects under three viewing conditions: two-dimension (2-D), stereoscopic 3-D, and prism. The participants performed each condition in a counter-balanced order. One-way repeated measures analysis of variance showed significant increases in the positive predictive values in the prism condition compared to the 2-D and 3-D conditions. Participants’ subjective ratings of realness and engagement were also significantly greater in the prism condition than in the 2-D and 3-D conditions, while the ratings for visual fatigue were significantly reduced in the prism condition than in the 3-D condition. The proposed methods are expected to enhance the sense of reality in 3-D space without causing critical visual fatigue. In addition, people who are especially susceptible to stereoscopic 3-D may be able to use the affective brain–computer interface.
3D objects with depth information can provide many benefits to users in education, surgery, and interactions. In particular, many studies have been done to enhance sense of reality in 3D interaction. Viewing and controlling stereoscopic 3D objects with crossed or uncrossed disparities, however, can cause visual fatigue due to the vergenceaccommodation conflict generally accepted in 3D research fields. In order to avoid the vergence-accommodation mismatch and provide a strong sense of presence to users, we apply a prism array-based display to presenting 3D objects. Emotional pictures were used as visual stimuli in control panels to increase information transfer rate and reduce false positives in controlling 3D objects. Involuntarily motivated selective attention by affective mechanism can enhance steady-state visually evoked potential (SSVEP) amplitude and lead to increased interaction efficiency. More attentional resources are allocated to affective pictures with high valence and arousal levels than to normal visual stimuli such as white-and-black oscillating squares and checkerboards. Among representative BCI control components (i.e., eventrelated potentials (ERP), event-related (de)synchronization (ERD/ERS), and SSVEP), SSVEP-based BCI was chosen in the following reasons. It shows high information transfer rates and takes a few minutes for users to control BCI system while few electrodes are required for obtaining reliable brainwave signals enough to capture users’ intention. The proposed BCI methods are expected to enhance sense of reality in 3D space without causing critical visual fatigue to occur. In addition, people who are very susceptible to (auto) stereoscopic 3D may be able to use the affective BCI.
Distortions in the perceived image characteristics for three different camera arrangements of parallel, converging, and
diverging are different according to each focal length, focus distance, field of view angle, color, magnification, and
camera aligning direction. The distortions in perceived image for the parallel and converging arrangements have been
researched commercially available stereoscopic TV based on high speed LCD, shutter glasses, and mobile devices.
However, the distortion in the perceived image for diverging arrangement is not well known. This paper discusses the
distortion in perceived image characteristics of diverging type stereo camera according to the magnification determining
the enlargement and reduction of a camera image, and they are compared with those of other camera arrangements such
as parallel and converging types. Also, the distortion induces the image closer to the viewers for the diverging type while
away for the converging. The inducement is more prominent as the camera distance between two component cameras of
the stereo camera for the diverging type. Furthermore, the effect of diverging angle on disparity will be considered that
the inter-camera distance can be made as small as possible.
With an advent of autostereoscopic display technique and increased needs for smart phones, there has been a significant
growth in mobile TV markets. The rapid growth in technical, economical, and social aspects has encouraged 3D TV
manufacturers to apply 3D rendering technology to mobile devices so that people have more opportunities to come into
contact with many 3D content anytime and anywhere. Even if the mobile 3D technology leads to the current market
growth, there is an important thing to consider for consistent development and growth in the display market. To put it
briefly, human factors linked to mobile 3D viewing should be taken into consideration before developing mobile 3D
technology. Many studies have investigated whether mobile 3D viewing causes undesirable biomedical effects such as
motion sickness and visual fatigue, but few have examined main factors adversely affecting human health. Viewing
distance is considered one of the main factors to establish optimized viewing environments from a viewer's point of
view. Thus, in an effort to determine human-friendly viewing environments, this study aims to investigate the effect of
viewing distance on human visual system when exposing to mobile 3D environments. Recording and analyzing
brainwaves before and after watching mobile 3D content, we explore how viewing distance affects viewing experience
from physiological and psychological perspectives. Results obtained in this study are expected to provide viewing
guidelines for viewers, help ensure viewers against undesirable 3D effects, and lead to make gradual progress towards a
human-friendly mobile 3D viewing.
Digital holography technology has been considered a powerful method for reconstructing real objects and displaying
completed 3D information. Although many studies on holographic displays have been conducted, research on interaction
methods for holographic displays is still in an early stage. For developing an appropriate interaction method for digital
holograms, a two-way interaction which is able to provide natural interaction between humans and holograms should be
considered. However, digital holography technology is not yet fully developed to make holograms capable of naturally
responding to human behaviors. Thus, the purpose of this study was to propose an alternative interaction method capable
of applying it to interacting with holograms in the future. In order to propose an intuitive interaction method based on
computer-generated objects, we utilized a depth camera, Kinect, which provides depth information per pixel. In doing so,
humans and environment surrounding them were captured by the depth camera. The captured depth images were
simulated on a virtual space and computer graphic objects were generated on the same virtual space. Detailed location
information of humans was continuously extracted to provide a natural interaction with the generated objects. In order to
easily identify whether two objects were overlapped or not, bounding volumes were generated around both humans and
objects, respectively. The local information of the bounding volumes was correlated with one another, which made it
possible for humans to control the computer-generated objects. Then, we confirmed a result of interaction through
computer generated holograms. As a result, we obtained extreme reduction of computation time accuracy within 80%
through bounding volume.
Brain Computer Interface (BCI) studies have been done to help people manipulate electronic devices in a 2D space but
less has been done for a vigorous 3D environment. The purpose of this study was to investigate the possibility of
applying Steady State Visual Evoked Potentials (SSVEPs) to a 3D LCD display. Eight subjects (4 females) ranging in
age between 20 to 26 years old participated in the experiment. They performed simple navigation tasks on a simple 2D
space and virtual environment with/without 3D flickers generated by a Flim-Type Patterned Retarder (FPR). The
experiments were conducted in a counterbalanced order. The results showed that 3D stimuli enhanced BCI performance,
but no significant effects were found due to the small number of subjects. Visual fatigue that might be evoked by 3D
stimuli was negligible in this study. The proposed SSVEP BCI combined with 3D flickers can allow people to control
home appliances and other equipment such as wheelchairs, prosthetics, and orthotics without encountering dangerous
situations that may happen when using BCIs in real world. 3D stimuli-based SSVEP BCI would motivate people to use
3D displays and vitalize the 3D related industry due to its entertainment value and high performance.