360 degree viewable floating autostereoscopic display using integral photography and multiple semitransparent mirrors

Omnidirectional mid-air image system using micro-mirror array plates

We proposed and implemented an omnidirectional mid-air image optical system that suppresses stray light and transmitted light. When micro-mirror array plates (MMAP) are integrated with view control films and rotated these optical elements at high speed, stray and transmitted light are effectively suppressed. This enables the visibility of omnidirectional mid-air image. We evaluated the effects of the view control film and high-speed rotation on the luminance and resolution of mid-air images, respectively. Our system facilitates the simultaneous viewing of mid-air images by multiple users, expanding the accessibility of mid-air image content to a large audience.

Omnidirectional 3D autostereoscopic aerial display with continuous parallax

We present anl omnidirectional 3D autostereoscopic aerial display with continuous parallax. Integral photography (IP) combined with polyhedron-shaped aerial imaging plates (AIPs) is utilized to achieve an extended view angle of 3D aerial images. With optical theoretical analysis and an aerial in situ rotation design, a 3D aerial display with an enlarged viewing angle is realized. In particular, the proposed 3D aerial display can realize any assigned angle within 360 deg. We also optimize the aerial display with artifact image removal and floating image brightness analysis. Experiments are performed to prove the 3D aerial display with full-motion parallax, continuous viewpoints, and multiplayer interaction. The proposed system is an attractive prospect of non-contact interaction and multi-person collaboration.

Compact in-line floating display system using a dihedral corner reflector array

We propose a compact type floating display system using a dihedral corner reflector array. Conventional floating displays using the dihedral corner reflector array usually have a folded configuration which makes the system bulky. The proposed technique achieves the compact in-line configuration using a pair of decentered lenses. The decentered lenses make the effective incident angle to the dihedral corner reflector array be tilted while maintaining the display panel and the dihedral corner reflector array in parallel. The ghost images are also refracted largely by the decentered lenses, being separated from the desired floating images. The proposed technique is verified by optical experiments.

Annular sector elemental image array generation method for tabletop integral imaging 3D display with smooth motion parallax

One of the important features of tabletop 3D displays is the annular viewing area above the display system. In this paper, we propose an annular sector elemental image array (ASEIA) generation method for the tabletop integral imaging 3D display to form the annular viewing zone with smooth motion parallax. The effective pixels of the elemental images are distributed as annular sector, and they are mapped from the perspective images captured by the ring-shaped camera array. Correspondingly, the viewing sub-zones can be formed with an annular sector configuration and can be seamlessly stitched by using the time division scheme. Compared with the previous approach with rectangular elemental image array (EIA) distribution, the number of viewing sub-zones is decreased from 360 to 10 for the same effect of smooth motion parallax. Meanwhile, rendering efficiency is improved. The experimental results show that the proposed method is feasible to produce 360-degree continuous viewpoints in an annular viewing zone.

Roadmap on 3D integral imaging: sensing, processing, and display

This Roadmap article on three-dimensional integral imaging provides an overview of some of the research activities in the field of integral imaging. The article discusses various aspects of the field including sensing of 3D scenes, processing of captured information, and 3D display and visualization of information. The paper consists of a series of 15 sections from the experts presenting various aspects of the field on sensing, processing, displays, augmented reality, microscopy, object recognition, and other applications. Each section represents the vision of its author to describe the progress, potential, vision, and challenging issues in this field.

Time-multiplexed light field display with 120-degree wide viewing angle

The light field display can provide vivid and natural 3D performance, which can find many applications, such as relics research and exhibition. However, current light field displays are constrained by the viewing angle, which cannot meet the expectations. With three groups directional backlights and a fast-switching LCD panel, a time-multiplexed light field display with a 120-degree wide viewing angle is demonstrated. Up to 192 views are constructed within the viewing range to ensure the right geometric occlusion and smooth parallax motion. Clear 3D images can be perceived at the entire range of viewing angle. Additionally, the designed holographic functional screen is used to recompose the light distribution and the compound aspheric lens array is optimized to balance the aberrations and improve the 3D display quality. Experimental results verify that the proposed light field display has the capability to present realistic 3D images of historical relics in 120-degree wide viewing angle.

A flipping-free 3D integral imaging display using a twice-imaging lens array

Integral imaging is a promising 3D visualization technique for reconstructing 3D medical scenes to enhance medical analysis and diagnosis. However, the use of lens arrays inevitably introduces flipped images beyond the field of view, which cannot reproduce the correct parallax relation. To avoid the flipping effect in optical reconstruction, a twice-imaging lens array based integral display is presented. The proposed lens arrangement, which consists of a light-controlling lens array, a field lens array and an imaging lens array, allows the light rays from each elemental image only pass through its corresponding lens unit. The lens arrangement is optimized with geometrical optics method, and the proposed display system is experimentally demonstrated. A full-parallax 3D medical scene showing continuous viewpoint information without flipping is reconstructed in 45° field of view.

Radially arranged dihedral corner reflector array for wide viewing angle of floating image without virtual image

We proposed a new type of dihedral corner reflector array (DCRA) called "radially arranged DCRA". Our radially arranged DCRA could display a floating, three-dimensional image with a wide viewing angle without producing virtual images because dihedral corner reflectors were radially arranged for the designed paths of rays. In this research, we designed a reflector array pattern and evaluated the viewing angle of the floating image displayed by our radially arranged DCRA. During evaluation, we measured the reflection ratio of the radially arranged DCRA and demonstrated a floating image. Compared with a conventional DCRA, our radially arranged DCRA could expand the viewing angle from ± 30° to ± 90° without producing virtual images.

Virtual image determination for mirrored surfaces

An object viewed via reflection from a mirrored surface is often perceived by the observer to be located behind the mirror's surface. The image of this object behind the mirror is known as its virtual image. Conventional methods for determining the location and shape of a virtual image for non-planar mirrors are complex and impractical unless both the observer and object are near the optical axis. We have developed a technique designed to be simple and practical for determining the location of a virtual image in a non-planar mirror far from the optical axis. Results using this technique were compared with known results from geometric optics for an object point on the optical axis of a parabola and for an object point imaged off the optical axis of a spherical mirror. These results were also in agreement with experimental measurements for a hemispherical mirror viewed at large angles with respect to its optical axis. This technique has applications for display devices or imaging tools utilizing curved, mirrored surfaces.

Determination of point of incidence for the case of reflection or refraction at spherical surface knowing two points lying on the ray

The paper is focused on the problem of determination of the point of incidence of a light ray for the case of reflection or refraction at the spherical optical surface, assuming that two fixed points in space that the sought light ray should go through are given. The requirement is that one of these points lies on the incident ray and the other point on the reflected/refracted ray. Although at first glance it seems to be a simple problem, it will be shown that it has no simple analytical solution. The basic idea of the solution is given, and it is shown that the problem leads to a nonlinear equation in one variable. The roots of the resulting nonlinear equation can be found by numerical methods of mathematical optimization. The proposed methods were implemented in MATLAB, and the proper function of these algorithms was verified on several examples.

No-reference stereoscopic image-quality metric accounting for left and right similarity map and spatial structure degradation

Blind quality assessment of 3D images is used to confront more real challenges than 2D images. In this Letter, we develop a no-reference stereoscopic image quality assessment (SIQA) model based on the proposed left and right (LR)-similarity map and structural degradation. In the proposed method, local binary pattern features are extracted from the cyclopean image that are effective for describing the distortion of 3D images. More importantly, we first propose the LR-similarity map that can indicate the stereopair quality and demonstrate that the use of LR-similarity information results in a consistent improvement in the performance. The massive experimental results on the LIVE 3D and IRCCyN IQA databases demonstrate that the designed model is strongly correlated to subjective quality evaluations and competitive to the state-of-the-art SIQA algorithms.

Directional view method for a time-sequential autostereoscopic display with full resolution

A time-sequential autostereoscopic three-dimensional (3D) display using a set of cylindrical optical elements (COEs) as the backlight steering is proposed. The operation principle of the system and its detailed design are described. In our system, the COEs control the direction of the backlight for the proposed system of the user's right and left views. Additionally, the displayed images can be observed under ambient lighting by implementing the high density light-emitting diode (LED) arrays. Compared to the first-generation array display, the image resolution is greatly improved by the addition of the time multiplexing technique. A prototype system using a set of COEs, LED arrays, two linear Fresnel lenses, and an elliptical diffuser is constructed. Here, the directional backlight beams are synchronized with the right and left images alternately displayed on the liquid crystal display (LCD) screen, and two convergent viewing zones are formed alternately in front of the user's eyes; then 3D images are perceived because of persistence of the vision of human eye. The experimental results show that the proposed method is a potential technology for 3D applications such as 3D television.

Optimizing visual comfort for stereoscopic 3D display based on color-plus-depth signals

Visual comfort is a long-facing problem in stereoscopic 3D (S3D) display. In this paper, targeting to produce S3D content based on color-plus-depth signals, a general framework for depth mapping to optimize visual comfort for S3D display is proposed. The main motivation of this work is to remap the depth range of color-plus-depth signals to a new depth range that is suitable to comfortable S3D display. Towards this end, we first remap the depth range globally based on the adjusted zero disparity plane, and then present a two-stage global and local depth optimization solution to solve the visual comfort problem. The remapped depth map is used to generate the S3D output. We demonstrate the power of our approach on perceptually uncomfortable and comfortable stereoscopic images.

Floating autostereoscopic 3D display with multidimensional images for telesurgical visualization

PURPOSE

We propose a combined floating autostereoscopic three-dimensional (3D) display approach for telesurgical visualization, which could reproduce live surgical scene in a realistic and intuitive manner.

METHODS

A polyhedron-shaped 3D display device is developed for spatially floating autostereoscopic 3D image. Integral videography (IV) technique is adopted to generate real-time 3D images. Combined two-dimensional (2D) and 3D displays are presented floatingly around the center of the display device through reflection of semitransparent mirrors. Intra-operative surgery information is fused and updated in the 3D display, so that telesurgical visualization could be enhanced remotely.

RESULTS

The experimental results showed that our approach can achieve a combined floating autostereoscopic display that presents 2D and 3D fusion images. The glasses-free IV 3D display has full parallax and can be observed by multiple persons from surrounding areas at the same time. Furthermore, real-time surgical scene could be presented and updated in a realistic and intuitive visualization platform. It is shown that the proposed method is feasible for facilitating telesurgical visualization.

CONCLUSION

The proposed floating autostereoscopic display device presents surgical information in an efficient form, so as to enhance operative cooperation and efficiency during operation. Combined presentation of imaging information is promising for medical applications.

Simulating binocular vision for no-reference 3D visual quality measurement

Perceptual quality measurement of three-dimensional (3D) visual signals has become a fundamental challenge in 3D imaging fields. This paper proposes a novel no-reference (NR) 3D visual quality measurement (VQM) metric that uses simulations of the primary visual cortex (V1) of binocular vision. As the major technical contribution of this study, perceptual properties of simple and complex cells are considered for NR 3D-VQM. More specifically, the metric simulates the receptive fields of simple cells (one class of V1 neurons) using Gaussian derivative functions, and the receptive fields of complex cells (the other class of V1 neurons) using disparity energy responses and binocular rivalry responses. Subsequently, various quality-aware features are extracted from the primary visual cortex; these will change in the presence of distortions. Finally, those features are mapped to the subjective quality score of the distorted 3D visual signal by using support vector regression (SVR). Experiments on two publicly available 3D databases confirm the effectiveness of our proposed metric, compared to the relevant full-reference (FR) and NR metrics.