This paper presents details of a system that allows for an evolutionary introduction of depth perception into the existing 2D digital TV framework. The work is part of the European Information Society Technologies (IST) project “Advanced Three-Dimensional Television System Technologies” (ATTEST), an activity, where industries, research centers and universities have joined forces to design a backwards-compatible, flexible and modular broadcast 3D-TV system. At the very heart of the described new concept is the generation and distribution of a novel data representation format, which consists of monoscopic color video and associated perpixel depth information. From these data, one or more “virtual” views of a real-world scene can be synthesized in real-time at the receiver side (i. e. a 3D-TV set-top box) by means of so-called depth-image-based rendering (DIBR) techniques. This publication will provide: (1) a detailed description of the fundamentals of this new approach on 3D-TV; (2) a comparison with the classical approach of “stereoscopic” video; (3) a short introduction to DIBR techniques in general; (4) the development of a specific DIBR algorithm that can be used for the efficient generation of high-quality “virtual” stereoscopic views; (5) a number of implementation details that are specific to the current state of the development; (6) research on the backwards-compatible compression and transmission of 3D imagery using state-of-the-art MPEG (Moving Pictures Expert Group) tools.

Depth-image-based rendering (DIBR), compression, and transmission for a new approach on 3D-TV

Visual discomfort has been the subject of considerable research in relation to stereoscopic and autostereoscopic displays. In this paper, the importance of various causes and aspects of visual discomfort is clarified. When disparity values do not surpass a limit of 1°, which still provides sufficient range to allow satisfactory depth perception in stereoscopic television, classical determinants such as excessive binocular parallax and accommodation-vergence conflict appear to be of minor importance. Visual discomfort, however, may still occur within this limit and we believe the following factors to be the most pertinent in contributing to this: (1) temporally changing demand of accommodation-vergence linkage, e.g., by fast motion in depth; (2) three-dimensional artifacts resulting from insufficient depth information in the incoming data signal yielding spatial and temporal inconsistencies; and (3) unnatural blur. In order to ad- equately characterize and understand visual discomfort, multiple types of measurements, both objective and subjective, are required. © 2009 Society for Imaging Science and Technology. DOI: 10.2352/J.ImagingSci.Technol.2009.53.3.030201

Visual Discomfort and Visual Fatigue of Stereoscopic Displays: A Review

Foreword. Series Editor's Foreword. Preface. 1. Liquid crystal physics.* Introduction.* Thermodynamics and statistic physics.* Orientational order.* Elastic properties of liquid crystals.* Response of liquid crystals to electro-magnetic fields.* Anchoring effects of nematic liquid crystal at surfaces. 2. Propagation of light in anisotropic optical medium.* Electromagnetic wave.* Polarization.* Propagation of light in uniform anisotropic optical media.* Propagation of light in cholesteric liquid crystals. 3. Optical modeling methods.* Jones matrix method.* Mueller matrix method.* Berreman 4x4 method. 4. Effects of Electric field on Liquid Crystals.* Dielectric interaction.* Flexoelectric Effect.* Ferroelectricity in liquid crystals. 5. Freedericksz transition.* Calculus of variation.* The Fredeericksz transition: statics.* The Freedericksz transition: dynamics. 6. Liquid Crystal Materials.* Introduction.* Refractive indices.* Dielectric constants.* Rotational Viscosity.* Elastic constant.* Figure-of-merits.* Refractive index matching between liquid crystals and polymers. 7. Modeling of liquid crystal director configuration.* Electric energy of liquid crystals.* Modeling electric field.* Simulation of liquid crystal director configuration. 8. Transmissive liquid crystal display.* Introduction.* Twisted nematic cells.* In plane switching (IPS) mode.* Vertical alignment (VA) mode.* Multi-domain Vertical Alignment (MVA) Cells.* Optically compensated bend (OCB) cell. 9. Reflective and Trasreflective display.* Introduction.* Reflective liquid crystal displays.* Transflector.* Classification of Transflective LCDs.* Dual-cell-gap Transflective LCDs.* Single-cell-gap Transflective LCDs.* Performance of transflective LCDs. 10. Liquid crystal display matrices, drive schemes and bistable displays.* Segmented displays.* Passive matrix displays and drive scheme.* Active Matrix Displays.* Bistable ferroelectric liquid crystal displays and drive scheme.* Bistable nematic displays.* Bistable cholesteric reflective display. 11. Liquid crystal/polymer composites. * Introduction.* Phase separation.* Scattering properties of liquid crystal/polymer composites.* Polymer dispersed liquid crystals.* Polymer stabilization liquid crystals.* Displays from liquid crystal/polymer composites. 12. Tunable liquid crystal photonic devices. * Introduction.* Laser beam steering.* Variable Optical Attenuators.* Tunable-Focus Lens.* Polarization-Independent LC Devices. Index.

Fundamentals of Liquid Crystal Devices

Visual comfort of binocular and 3D displays

A depth-image-based rendering system for generating stereoscopic images is proposed. One important aspect of the proposed system is that the depth maps are pre-processed using an asymmetric filter to smoothen the sharp changes in depth at object boundaries. In addition to ameliorating the effects of blocky artifacts and other distortions contained in the depth maps, the smoothing reduces or completely removes newly exposed (disocclusion) areas where potential artifacts can arise from image warping which is needed to generate images from new viewpoints. The asymmetric nature of the filter reduces the amount of geometric distortion that might be perceived otherwise. We present some results to show that the proposed system provides an improvement in image quality of stereoscopic virtual views while maintaining reasonably good depth quality.

Stereoscopic image generation based on depth images for 3D TV

This paper discusses the origins, characteristics and effects of image distortions in stereoscopic video systems. The geometry of stereoscopic camera and display systems is presented first. This is followed by the analysis and diagrammatic presentation of various image distortions such as depth plane curvature, depth non-linearity, depth and size magnification, shearing distortion and keystone distortion. The variation of system parameters is also analyzed with the help of plots of image geometry to show their effects on image distortions. The converged (toed-in) and parallel camera configurations are compared and the amount of vertical parallax induced by lens distortion and keystone distortion are discussed. The range of acceptable vertical parallax and the convergence/accommodation limitations on depth range are also discussed. It is shown that a number of these distortions can be eliminated by the appropriate choice of camera and display systems parameters. There are some image distortions, however, which cannot be avoided due to the nature of human vision and limitations of current stereoscopic video display techniques.

/pdf/image-distortions-in-stereoscopic-video-systems-2w340944ca.pdf

Image distortions in stereoscopic video systems

Crosstalk is a critical factor determining the image quality of stereoscopic displays. Also known as ghosting or leakage, high levels of crosstalk can make stereoscopic images hard to fuse and lack fidelity; hence it is important to achieve low levels of crosstalk in the development of high-quality stereoscopic displays. In the wider academic literature, the terms crosstalk, ghosting and leakage are often used interchangeably but it would be helpful to have unambiguous descriptive and mathematical definitions of these terms. The paper reviews a wide range of mechanisms by which crosstalk occurs in various stereoscopic displays, including: time-sequential on PDPs and CRTs (phosphor afterglow, shutter timing, shutter efficiency), MicroPol LCDs (polarization quality, viewing angle), time-sequential on LCDs (pixel response rate, update method, shutter timing & efficiency), autostereoscopic (inter-zone crosstalk), polarised projection (quality of polarisers and screens), anaglyph (spectral quality of glasses and displays). Crosstalk reduction and crosstalk cancellation are also discussed along with methods of measuring and characterising crosstalk.

/pdf/understanding-crosstalk-in-stereoscopic-displays-1hsetlftda.pdf

Understanding Crosstalk in Stereoscopic Displays

Crosstalk, also known as ghosting or leakage, is a primary factor in determining the image quality of stereoscopic three dimensional (3D) displays. In a stereoscopic display, a separate perspective view is presented to each of the observer's two eyes in order to experience a 3D image with depth sensation. When crosstalk is present in a stereoscopic display, each eye will see a combination of the image intended for that eye, and some of the image intended for the other eye-making the image look doubled or ghosted. High levels of crosstalk can make stereoscopic images hard to fuse and lack fidelity, so it is important to achieve low levels of crosstalk in the development of high-quality stereoscopic displays. Descriptive and mathematical definitions of these terms are formalized and summarized. The mechanisms by which crosstalk occurs in different stereoscopic display technologies are also reviewed, including micropol 3D liquid crystal displays (LCDs), autostereoscopic (lenticular and parallax barrier), polarized projection, anaglyph, and time-sequential 3D on LCDs, plasma display panels and cathode ray tubes. Crosstalk reduction and crosstalk cancellation are also discussed along with methods of measuring and simulating crosstalk.

https://www.spiedigitallibrary.org/journals/Journal-of-Electronic-Imaging/volume-21/issue-4/040902/Crosstalk-in-stereoscopic-displays-a-review/10.1117/1.JEI.21.4.040902.pdf

Crosstalk in stereoscopic displays: A review

Crosstalk is a critical factor determining the image quality of stereoscopic displays. Also known as ghosting or leakage, high levels of crosstalk can make stereoscopic images hard to fuse and lack fidelity; hence it is important to achieve low levels of crosstalk in the development of high-quality stereoscopic displays. In the wider academic literature, the terms crosstalk, ghosting and leakage are often used interchangeably and unfortunately very few publications actually provide a descriptive or mathematical definition of these terms. Additionally the definitions that are available are sometimes contradictory. This paper reviews how the terms crosstalk, ghosting and associated terms (system crosstalk, viewer crosstalk, gray-to-gray crosstalk, leakage, extinction and extinction ratio, and 3D contrast) are defined and used in the stereoscopic literature. Both descriptive definitions and mathematical definitions are considered.

http://cmst.curtin.edu.au/wp-content/uploads/sites/4/2016/05/2011-14-woods-crosstalk_and_ghosting.pdf

How are Crosstalk and Ghosting defined in the Stereoscopic Literature

A common artefact of time-sequential stereoscopic video displays is the presence of some image ghosting or crosstalk between the two eye views. In general this happens because of imperfect shuttering of the Liquid Crystal Shutter (LCS) glasses used, and the afterglow of one image into another due to phosphor persistence. This paper describes a project that has measured and quantified these sources of image ghosting and developed a mathematical model of stereoscopic image ghosting. The primary parameters which have been measured for use in the model are: the spectral response of the red, green and blue phosphors for a wide range of monitors, the phosphor decay rate of same, and the transmission response of a wide range of LCS glasses. The model compares reasonably well with perceived image ghosting. This paper aims to provide the reader with an improved understanding of the mechanisms of stereoscopic image ghosting and to provide guidance in reducing image ghosting in time-sequential stereoscopic displays.

Andrew J. Woods

Papers

Image distortions in stereoscopic video systems

Understanding Crosstalk in Stereoscopic Displays

Crosstalk in stereoscopic displays: A review

How are Crosstalk and Ghosting defined in the Stereoscopic Literature

Characterizing sources of ghosting in time-sequential stereoscopic video displays