Multi‐view 3‐D display employing a flat‐panel display with slanted pixel arrangement

Abstract— A flat‐panel display with a slanted subpixel arrangement has been developed for a multi‐view three‐dimensional (3‐D) display. A set of 3M × N subpixels (M × N subpixels for each R, G, and B color) corresponds to one of the cylindrical lenses, which constitutes a lenticular lens, to construct each 3‐D pixel of a multi‐view display that offers M × N views. Subpixels of the same color in each 3‐D pixel have different horizontal positions, and the R, G, and B subpixels are repeated in the horizontal direction. In addition, the ray‐emitting areas of the subpixels within a 3‐D pixel are continuous in the horizontal direction for each color. One of the vertical edges of each subpixel has the same horizontal position as the opposite vertical edge of another subpixel of the same color. Cross‐talk among viewing zones is theoretically zero. This structure is suitable for providing a large number of views. A liquid‐crystal panel having this slanted subpixel arrangement was fabricated to construct a mobile 3‐D display with 16 views and a 3‐D resolution of 256 × 192. A 3‐D pixel is comprised of 12 × 4 subpixels (M = 4 and N = 4). The screen size was 2.57 in.     

Improving resolution and image space in a static volumetric 3‐D display

Abstract— Improvements achieved in image resolution and volume in a volumetric display based on the two‐frequency, two‐step upconversion (TFTS) method are presented. Two digital micromirror devices (DMDs) are utilized to generate fast scanning of the image volume at high resolution. Improvements in resolution and image size over previous implementations are achieved by choosing sodium—ytterbium—fluoride for the imaging crystal instead of the conventional ytterbium—lithium—fluoride composition. Experimentally, images at 532 nm were constructed using 45 slices with each slice rendered at 1024 × 768 resolution, resulting in almost 35 million voxels. The resulting system has the potential to achieve a resolution beyond a targeted 800 million voxels without viewpoint obstruction and with expandability to three‐color imagery.     

Design conditions for attractive reality in mobile‐type 3‐D display

Abstract— An autostereoscopic 3‐D display suitable for the mobile environment is prototyped and evaluated. First, the required conditions for a 3‐D display in a mobile environment are considered, and the three major requirements are clarified: small size, viewing‐position flexibility, and application support. An application of a mobile‐type 3‐D display should be different from that of a large‐sized 3‐D display because a mobile‐type 3‐D display cannot realize the feeling of immersion while large‐sized 3‐D displays can realize it easily. From this assumption, it is considered that it is important to realize the feeling to handle a 3‐D image. Three types of 3‐D displays are developed to satisfy these requirements. They are subjectively evaluated to confirm their attractiveness. Results of the tests show that intuitive interaction can increase the reality of the 3‐D image in the sense of unity and also can improve the solidity and depth impression of the 3‐D image.     

Development of a 42‐in. 2‐D/3‐D switchable display using multi‐view technology for public‐information‐display applications

Abstract— A 42‐in. 2‐D/3‐D switchable display operating in a parallax‐barrier‐type system consisting of liquid‐crystal displays (LCDs) has been developed. The system displays 2‐D images in full resolution, without any degradation to the original 2‐D images, and 3‐D autostereoscopic images with resolutions higher than SVGA with wide viewing zones electrically controlled by the parallax‐barrier system. The system is intended for use in public‐information displays (PIDs), a booming field, and as displays for gaming, medical, and simulation applications.     

3‐D crosstalk and luminance uniformity from angular luminance profiles of multiview autostereoscopic 3‐D displays

Abstract— Autostereoscopic 3‐D display technologies enable a more immersive media experience by adding real depth to the visual content. However, the method used for the creation of a sensation of depth or stereo illusion contains several display design and content‐related issues that need to be carefully considered to maintain sufficient image quality. Conventionally, methods used for 3‐D image‐quality evaluations have been based on subjective testing. Optical measurements, in addition to subjective testing, can be used as an efficient tool for 3‐D display characterization. Objective characterization methods for autostereoscopic displays have been developed. How parameters affecting stereo image quality can be defined and measured, and how their effect on the stereo image quality can be evaluated have been investigated. Developed characterization methods are based on empirically gathered data. In this paper, previously presented methodology for two‐view displays is extended to cover autostereoscopic multiview displays. A distinction between displays where the change in content occurs in clear steps when the user moves in front of the display, and displays where the apparent movement of the objects is more continuous as a function of the head movement is made. Definitions for 3‐D luminance and luminance uniformity, which are equally important, as well as 3‐D crosstalk, which is the dominant factor in the evaluations of the perceived 3‐D image quality, is focused upon.     

Optical characterization of autostereoscopic 3‐D displays

Abstract— Display‐measurement methods different from conventional 2‐D display measurements are needed for verifying the optical characteristics of autostereoscopic (3‐D) displays and for comparing different 3‐D display technologies. Industry is lacking standardized measurement methods, and the reported results can not always be compared. The selected set of characteristics discussed in this paper and partly defining the quality of the 3‐D experience are crosstalk, viewing freedom, and optimum viewing distance. Also, more conventional display characteristics such as luminance are discussed, since the definitions for these characteristics in 3‐D mode usually differ from those used for the 2D displays. We have investigated how these chosen 3‐D display characteristics can be objectively measured from transmissive two‐view and multiview 3‐D displays. The scope of this article is to generally define those basic characteristics as well as the different measurement methods. Most of the 3‐D characteristics can be derived from the luminance and colors versus the viewing angle. Either a conoscopic or a goniometric measurement system can be used, as long as the angular and stray‐light properties are suitable and known. The characteristics and methods are currently discussed in the display‐quality standardization forums.     

Hybrid MEMS optical scanner for volumetric 3‐D displays

Abstract— A fabrication technique and characteristics of high‐power‐handling microelectromechanical systems (MEMS) optical scanners for laser 3‐D volumetric‐image display application is reported. The MEMS scanner is designed to control the reflection of high‐power YAG‐laser beam by using the optomechanical combination of a dielectric‐film‐coated mirror cube and an electrostatic‐MEMS‐scanner platform. These hybrid‐type MEMS optical scanners have a stroke of about 20° at resonant frequencies of 600 Hz when a 45‐V pulse voltage is applied.     

Dual‐lenticular‐lens‐based 2‐D/3‐D convertible autostereoscopic display

Abstract— A 2‐D/3‐D convertible display using two lenticular lenses has been developed. It shows 2‐D pictures in full resolution and 3‐D autostereoscopic pictures in half resolution by moving one lens relative to the other. The lens assembly consists of thin metal frames, two lenticular lenses, and two shape‐memory‐alloy (SMA) wires used as actuators. While this assembly is applicable to flat‐panel displays of any kind, its simple structure and low power consumption make it best suited to mobile terminals, such as PDAs and mobile phones. Here, we describe its structure and present evaluation results.     

MUTED: Multi‐user 3‐D display

Abstract— Research described in this paper encompasses the design and building of glasses‐free (autostereoscopic) displays that utilize a direct‐view liquid‐crystal display whose backlight is provided by a projector and novel steering optics. This is controlled by the output of a multi‐user head‐position tracker. As the displays employ spatial multiplexing on a liquid‐crystal‐display screen, they are inherently 2‐D/3‐D switchable with 2‐D being achieved by simply displaying the same image in the left and right channels. Two prototypes are described in this paper; one incorporating a holographic projector and the other a conventional LCOS projector. The LCOS projector version addresses the limitations of brightness, cross‐talk, banding in the images, and laser stability that occur in the holographic projector version. The future development is considered and a comparison between the prototypes and with other 3‐D displays is given.     

Prototyping and optical evaluation of 9‐in. OCB time‐division‐multiplexing 18‐view 3‐D display

Abstract— An integral imaging time‐division‐multiplexing 18‐view 3‐D display based on the one‐dimensional integral‐imaging (1‐D‐II) technique using a 9‐in. OCB‐LCD, lenticular sheet, and active shutter has been developed. By simulating a lens shape and a shutter structure and analyzing the light‐beam profile of the increasing‐parallax‐number region to find the best conditions, depth range, and viewing angle were an enhanced and a brighter and flicker‐less 3‐D image with smooth motion parallax was obtained.     

Invited Paper: Depth reproducibility of multiview depth‐fused 3‐D display

Abstract— A multi‐view depth‐fused 3‐D (DFD) display that provides smooth motion parallax for wide viewing angles is proposed. A conventional DFD display consists of a stack of two transparent emitting screens. It can produce motion parallax for small changes in observation angle, but its viewing zone is rather narrow due to the split images it provides in inclined views. On the other hand, even though multi‐view 3‐D displays have a wide viewing angle, motion parallax in them is discrete, depending on the number of views they show. By applying a stacked structure to multi‐view 3‐D displays, a wide‐viewing‐angle 3‐D display with smooth motion parallax was fabricated. Experimental results confirmed the viewing‐zone connection of DFD displays while the calculated results show the feasibility of stacked multi‐view displays.     

2‐D/3‐D switchable displays

Abstract— In this paper, the design of a lenticular‐based 2‐D/3‐D display for mobile applications is described. This display combines look‐around capability with good 3‐D resolution. In order to allow high‐resolution datagraphic applications, a concept based on actively switched lenses has been developed. A very noticeable problem for such displays is the occurrence of dark bands. Despite slanting the lenticular and defocusing the lens, banding becomes unacceptable when the display is viewed from an angle. As a solution, fractional viewing systems to reduce the banding intensity by almost two orders of magnitude is introduced. The resulting 3‐D display can be viewed from any horizontal direction without banding.     

The construction and performance of a multiviewer 3‐D television display

Abstract— The De Montfort University (DMU) autostereoscopic 3‐D display, intended for television applications, is described. It provides freedom of viewer movement over a typical “living room” sized area, with no restrictions on viewer's head positions. The display is capable of supplying 3‐D images to multiple viewers who do not need to wear special glasses. It operates by producing regions (exit pupils) in the viewing field where either a left or a right image is perceived. The positions of the exit pupils are steered to the viewers' eyes by the use of head tracking. Design issues that became apparent during the construction of a first prototype, and the findings from tests on it, are described. In addition, the current status of a more advanced prototype is reported.     

True 3‐D scanned voxel displays using single or multiple light sources

Abstract— Conventional stereoscopic displays require viewers to unnaturally keep eye accommodation fixed at one focal distance while they dynamically change vergence to view objects at different distances. This forced decoupling of reflexively linked processes fatigues eyes, causes discomfort, compromises image quality, and may lead to pathologies in developing visual systems. Volumetric displays can overcome this conflict, but only for small objects placed within a limited range of viewing distances and accommodation levels, and cannot render occlusion cues correctly. Our multi‐planar True 3‐D displays generate accommodation cues that match vergence and stereoscopic retinal disparity demands and can display images and objects at viewing distances throughout the full range of human accommodation (from 6.25 cm to infinity), better mimicking natural vision and minimizing eye fatigue.     

Static‐volumetric display using rotational‐slicing approach for rendering 3‐D images

Abstract— This work is related to static volumetric crystals which scintillate light when two laser beams are intersected within the crystal. The geometry in this crystal is optimized for linear slices. Most volumetric displays are based on rotational surfaces, which generate the images, while the projected images are sliced in a rotational sweep mode. To date, the majority of 3‐D graphic engines based on static‐volume displays have not been fully developed. To use an advanced 3‐D graphic engine designed for a swept‐volume display (SVD) with a static‐volume display, the display must emulate the operation of a SVD based on a rotational‐slicing approach. The CSpace® 3‐D display has the capability to render 3‐D images using the rotational‐slicing approach. This paper presents the development of a rotational‐slicing approach designed to emulate the operation of a SVD within the image volume of a static‐volume display. The display software has been modified to divide the 3‐D image into 46 slices, each passing through the image center and rotated at a fixed angle from the previous slice. Reconstructed 3‐D images were demonstrated using a rotational‐slicing approach. Suggestions are provided for future implementations that could aid in the elimination of elongations and distortions, which occur within specified slices.     

High‐resolution autostereoscopic 3‐D projection display with a space‐dividing iris‐plane shutter

Abstract— A high‐resolution autostereoscopic 3‐D projection display with a polarization‐control space dividing the iris‐plane liquid‐crystal shutter is proposed. The polarization‐control iris‐plane shutter can control the direction of stereo images without reducing the image quality of the microdis‐play. This autostereoscopic 3‐D projection display is 2‐D/3‐D switchable and has a high resolution and high luminance. In addition, it has no cross‐talk between the left and right viewing zones, a simple structure, and the capability to show multi‐view images.     

3‐D mobile display based on dual‐directional light guides with a fast‐switching liquid‐crystal panel

Abstract— An autostereoscopic display based on dual‐directional light guides with a fast‐switching liquid‐crystal panel was designed and fabricated to provide better 3‐D perception with image qualities comparable to that of 2‐D displays. With two identical micro‐grooved light guides, each with a light‐controlled ability in one direction, two restricted viewing cones are formed to project pairs of parallax images to the viewer's respective eyes sequentially. Crosstalk of less than 10% located within ±8°–±30° and an LC response time of 7.1 msec for a 1.8‐in. LCD panel can yield acceptable 3‐D perceptions at viewing distance of 5.6–23 cm. Moreover, 2‐D/3‐D compatibility is provided in this module.     

2‐D/3‐D displays based on switchable lenticulars

Abstract— An attractive concept for 3‐D displays is the one based on LCDs equipped with lenticular lenses. This enables autostereoscopic multiview 3‐D displays without a loss in brightness. A general issue in multiview 3‐D displays is their relatively low spatial resolution because the pixels are divided among the different views. To overcome this problem, we have developed switchable displays, using liquid‐crystal (LC) filled switchable lenticulars. In this way, it is possible to have a high‐brightness 3‐D display capable of fully exploiting the native 2‐D resolution of the underlying LCD. The feasibility of LC‐filled switchable lenticulars was shown in several applications. For applications in which it is advantageous to be able to display 3‐D and 2‐D content simultaneously, a 42‐in. locally switchable prototype having a matrix electrode structure was developed. These displays were realized using cylindrically shaped lenticular lenses in contact with LC. An alternative for these are lenticulars based on gradient‐index (GRIN) LC lenses. Preliminary results for such switchable GRIN lenses are presented as well.     

Bare finger 3D air‐touch system with embedded multiwavelength optical sensor arrays for mobile 3D displays

A camera‐free 3D air‐touch system was proposed. Hovering, air swiping, and 3D gestures for further interaction with the floated 3D images on the mobile display were demonstrated. By embedding multiwavelength optical sensors into the display pixels and adding angular‐scanning illuminators with multiwavelength on the edge of the display, the flat panel can sense images reflected by a bare finger from different heights. In addition, three axis (x, y, z) information of the reflected image of the fingertip can be calculated. Finally, the proposed 3D air‐touch system was successfully demonstrated on a 4‐inch mobile 3D display.     

High‐visibility 2‐D/3‐D LCD with HDDP arrangement and its optical characterization methods

Abstract— A 3.1‐in.‐diagonal 2‐D/3‐D LCD with a novel pixel arrangement, called horizontally double‐density pixels (HDDP), for high‐quality 3‐D images has been developed. 3‐D visibility has been improved by broadening the qualified stereoscopic viewing space (QSVS) where high‐quality 3‐D images can be seen. In order to evaluate the QSVS, optical characterization methods, based on the ergonomics for stereoscopy, such as 3‐D crosstalk, interocular luminance difference and 3‐D moiré have been proposed. The implementation results show that these methods can correctly evaluate high‐visibility autostereoscopic displays.