Crosstalk in stereoscopic displays

Crosstalk is an important image quality attribute of stereoscopic 3D displays. The research presented in this thesis examines the presence, mechanisms, simulation, and reduction of crosstalk for a selection of stereoscopic display technologies. High levels of crosstalk degrade the perceived quality of stereoscopic displays hence it is important to minimise crosstalk. This thesis provides new insights which are critical to a detailed understanding of crosstalk and consequently to the development of effective crosstalk reduction techniques

High-efficiency Blue Phase Liquid Crystal Displays

Blue phase liquid crystals (BPLCs) have a delicate lattice structure existing between chiral nematic and isotropic phases, with a stable temperature range of about 2 K. But due to short coherent length, these self-assembled nano-structured BPLCs have a fast response time. In the past three decades, the application of BPLC has been rather limited because of its narrow temperature range. In 2002, Kikuchi et al. developed a polymer stabilization method to extend the blue-phase temperature range to more than 60 K. This opens a new gateway for display and photonic applications. In this dissertation, I investigate the material properties of polymer-stabilized BPLCs. According the Gerber’s model, the Kerr constant of a BPLC is linearly proportional to the dielectric anisotropy of the LC host. Therefore, in the frequency domain, the relaxation of the Kerr constant follows the same trend as the dielectric relaxation of the host LC. I have carried out experiments to validate the theoretical predictions, and proposed a model called extended Cole-Cole model to describe the relaxation of the Kerr constant. On the other hand, because of the linear relationship, the Kerr constant should have the same sign as the dielectric anisotropy of the LC host; that is, a positive or negative Kerr constant results from positive (∆ε \u3e 0) or negative host LCs (∆ε \u3c 0), respectively. BPLCs with a positive Kerr constant have been studied extensively, but there has been no study on negative ∆ε polymer-stabilized BPLCs. Therefore, I have prepared a BPLC mixture using a negative ∆ε LC host and investigated its electro-optic properties. I have demonstrated that indeed the induced birefringence and Kerr constant are of negative sign. Due to the fast response time of BPLCs, color sequential display is made possible without color breakup. By removing the spatial color filters, the optical efficiency and resolution density are both tripled. With other advantages such as alignment free and wide viewing angle, polymer-stabilized BPLC is emerging as a promising candidate for next-generation displays. However, the optical efficiency of the BPLC cell is relatively low and the operating voltage is quite high using conventional in-plane-switching electrodes. I have proposed several device structures for improving the optical efficiency of transmissive BPLC cells. Significant improvement in transmittance is achieved by using enhanced protrusion electrodes, and a 100% transmittance is achievable using complementary enhanced protrusion electrode structure. For a conventional transmissive blue phase LCD, although it has superb performances indoor, when exposed to strong sunlight the displayed images could be washed out, leading to a degraded contrast ratio and readability. To overcome the sunlight readability problem, a common approach is to adaptively boost the backlight intensity, but the tradeoff is in the increased power consumption. Here, I have proposed a transflective blue phase LCD where the backlight is turned on in dark surroundings while ambient light is used to illuminate the displayed images in bright surroundings. Therefore, a good contrast ratio is preserved even for a strong ambient. I have proposed two transflective blue phase LCD structures, both of which have single cell gap, single gamma driving, reasonably wide view angle, low power consumption, and high optical efficiency. Among all the 3D technologies, integral imaging is an attractive approach due to its high efficiency and real image depth. However, the optimum observation distance should be adjusted as the displayed image depth changes. This requires a fast focal length change of an adaptive lens array. BPLC adaptive lenses are a good candidate because of their intrinsic fast response time. I have proposed several BPLC lens structures which are polarization independent and exhibit a parabolic phase profile in addition to fast response time. To meet the low power consumption requirement set by Energy Star, high optical efficiency is among the top lists of next-generation LCDs. In this dissertation, I have demonstrated some new device structures for improving the optical efficiency of a polymerstabilized BPLC transmissive display and proposed sunlight readable transflective blue-phase LCDs by utilizing ambient light to reduce the power consumption. Moreover, we have proposed several blue-phase LC adaptive lenses for high efficiency 3D displays

Perceived Depth Control in Stereoscopic Cinematography

Despite the recent explosion of interest in the stereoscopic 3D (S3D) technology, the ultimate prevailing of the S3D medium is still significantly hindered by adverse effects regarding the S3D viewing discomfort. This thesis attempts to improve the S3D viewing experience by investigating perceived depth control methods in stereoscopic cinematography on desktop 3D displays. The main contributions of this work are: (1) A new method was developed to carry out human factors studies on identifying the practical limits of the 3D Comfort Zone on a given 3D display. Our results suggest that it is necessary for cinematographers to identify the specific limits of 3D Comfort Zone on the target 3D display as different 3D systems have different ranges for the 3D Comfort Zone. (2) A new dynamic depth mapping approach was proposed to improve the depth perception in stereoscopic cinematography. The results of a human-based experiment confirmed its advantages in controlling the perceived depth in viewing 3D motion pictures over the existing depth mapping methods. (3) The practicability of employing the Depth of Field (DoF) blur technique in S3D was also investigated. Our results indicate that applying the DoF blur simulation on stereoscopic content may not improve the S3D viewing experience without the real time information about what the viewer is looking at. Finally, a basic guideline for stereoscopic cinematography was introduced to summarise the new findings of this thesis alongside several well-known key factors in 3D cinematography. It is our assumption that this guideline will be of particular interest not only to 3D filmmaking but also to 3D gaming, sports broadcasting, and TV production

Head Tracked Multi User Autostereoscopic 3D Display Investigations

The research covered in this thesis encompasses a consideration of 3D television requirements and a survey of stereoscopic and autostereoscopic methods. This confirms that although there is a lot of activity in this area, very little of this work could be considered suitable for television. The principle of operation, design of the components of the optical system and evaluation of two EU-funded (MUTED & HELIUM3D projects) glasses-free (autostereoscopic) displays is described. Four iterations of the display were built in MUTED, with the results of the first used in designing the second, third and fourth versions. The first three versions of the display use two-49 element arrays, one for the left eye and one for the right. A pattern of spots is projected onto the back of the arrays and these are converted into a series of collimated beams that form exit pupils after passing through the LCD. An exit pupil is a region in the viewing field where either a left or a right image is seen across the complete area of the screen; the positions of these are controlled by a multi-user head tracker. A laser projector was used in the first two versions and, although this projector operated on holographic principles in order to obtain the spot pattern required to produce the exit pupils, it should be noted that images seen by the viewers are not produced holographically so the overall display cannot be described as holographic. In the third version, the laser projector is replaced with a conventional LCOS projector to address the stability and brightness issues discovered in the second version. In 2009, true 120Hz displays became available; this led to the development of a fourth version of the MUTED display that uses 120Hz projector and LCD to overcome the problems of projector instability, produces full-resolution images and simplifies the display hardware. HELIUM3D: A multi-user autostereoscopic display based on laser scanning is also described in this thesis. This display also operates by providing head-tracked exit pupils. It incorporates a red, green and blue (RGB) laser illumination source that illuminates a light engine. Light directions are controlled by a spatial light modulator and are directed to the users’ eyes via a front screen assembly incorporating a novel Gabor superlens. In this work is described that covered the development of demonstrators that showed the principle of temporal multiplexing and a version of the final display that had limited functionality; the reason for this was the delivery of components required for a display with full functionality

Panoramic, large-screen, 3-D flight display system design

The report documents and summarizes the results of the required evaluations specified in the SOW and the design specifications for the selected display system hardware. Also included are the proposed development plan and schedule as well as the estimated rough order of magnitude (ROM) cost to design, fabricate, and demonstrate a flyable prototype research flight display system. The thrust of the effort was development of a complete understanding of the user/system requirements for a panoramic, collimated, 3-D flyable avionic display system and the translation of the requirements into an acceptable system design for fabrication and demonstration of a prototype display in the early 1997 time frame. Eleven display system design concepts were presented to NASA LaRC during the program, one of which was down-selected to a preferred display system concept. A set of preliminary display requirements was formulated. The state of the art in image source technology, 3-D methods, collimation methods, and interaction methods for a panoramic, 3-D flight display system were reviewed in depth and evaluated. Display technology improvements and risk reductions associated with maturity of the technologies for the preferred display system design concept were identified

State of the art 3D technologies and MVV end to end system design

L’oggetto del presente lavoro di tesi è costituito dall’analisi e dalla recensione di tutte le tecnologie 3D: esistenti e in via di sviluppo per ambienti domestici; tenendo come punto di riferimento le tecnologie multiview video (MVV). Tutte le sezioni della catena dalla fase di cattura a quella di riproduzione sono analizzate. Lo scopo è di progettare una possibile architettura satellitare per un futuro sistema MVV televisivo, nell’ambito di due possibili scenari, broadcast o interattivo. L’analisi coprirà considerazioni tecniche, ma anche limitazioni commerciali

Méthodes pour l'évaluation et la prédiction de la Qualité d'expérience, la préférence et l'inconfort visuel dans les applications multimédia. Focus sur la TV 3D stéréoscopique

Multimedia technology is aiming to improve people's viewing experience, seeking for better immersiveness and naturalness. The development of HDTV, 3DTV, and Ultra HDTV are recent illustrative examples of this trend. The Quality of Experience (QoE) in multimedia encompass multiple perceptual dimensions. For instance, in 3DTV, three primary dimensions have been identified in literature: image quality, depth quality and visual comfort. In this thesis, focusing on the 3DTV, two basic questions about QoE are studied. One is "how to subjectively assess QoE taking care of its multidimensional aspect?". The other is dedicated to one particular dimension, i.e., "what would induce visual discomfort and how to predict it?". In the first part, the challenges of the subjective assessment on QoE are introduced, and a possible solution called "Paired Comparison" is analyzed. To overcome drawbacks of Paired Comparison method, a new formalism based on a set of optimized paired comparison designs is proposed and evaluated by different subjective experiments. The test results verified efficiency and robustness of this new formalism. An application is the described focusing on the evaluation of the influence factor on 3D QoE. In the second part, the influence of 3D motion on visual discomfort is studied. An objective visual discomfort model is proposed. The model showed high correlation with the subjective data obtained through various experimental conditions. Finally, a physiological study on the relationship between visual discomfort and eye blinking rate is presented.La technologie multimédia vise à améliorer l'expérience visuelle des spectateurs, notamment sur le plan de l'immersion. Les développements récents de la TV HD, TV 3D, et TV Ultra HD s'inscrivent dans cette logique. La qualité d'expérience (QoE) multimédia implique plusieurs dimensions perceptuelles. Dans le cas particulier de la TV 3D stéréoscopique, trois dimensions primaires ont été identifiées dans la littérature: qualité d'image, qualité de la profondeur et confort visuel. Dans cette thèse, deux questions fondamentales sur la QoE sont étudiés. L'une a pour objet "comment évaluer subjectivement le caractère multidimensionnel de la QoE". L'autre s'intéresse à une dimension particuliére de QoE, "la mesure de l'inconfort et sa prédiction?". Dans la première partie, les difficultés de l'évaluation subjective de la QoE sont introduites, les mérites de méthodes de type "Comparaison par paire" (Paired Comparison en anglais) sont analysés. Compte tenu des inconvénients de la méthode de Comparaison par paires, un nouveau formalisme basé sur un ensemble de comparaisons par paires optimisées, est proposé. Celui-ci est évalué au travers de différentes expériences subjectives. Les résultats des tests confirment l'efficacité et la robustesse de ce formalisme. Un exemple d'application dans le cas de l'étude de l'évaluation des facteurs influençant la QoE est ensuite présenté. Dans la seconde partie, l'influence du mouvement tri-dimensionnel (3D) sur l'inconfort visuel est étudié. Un modèle objectif de l'inconfort visuel est proposé. Pour évaluer ce modèle, une expérience subjective de comparaison par paires a été conduite. Ce modèle de prédiction conduit à des corrélations élevées avec les données subjectives. Enfin, une étude sur des mesures physiologiques tentant de relier inconfort visuel et fréquence de clignements des yeux présentée

Une méthode pour l'évaluation de la qualité des images 3D stéréoscopiques.

Dans le contexte d'un intérêt grandissant pour les systèmes stéréoscopiques, mais sans méthodes reproductible pour estimer leur qualité, notre travail propose une contribution à la meilleure compréhension des mécanismes de perception et de jugement humains relatifs au concept multi-dimensionnel de qualité d'image stéréoscopique. Dans cette optique, notre démarche s'est basée sur un certain nombre d'outils : nous avons proposé un cadre adapté afin de structurer le processus d'analyse de la qualité des images stéréoscopiques, nous avons implémenté dans notre laboratoire un système expérimental afin de conduire plusieurs tests, nous avons crée trois bases de données d'images stéréoscopiques contenant des configurations précises et enfin nous avons conduit plusieurs expériences basées sur ces collections d'images. La grande quantité d'information obtenue par l'intermédiaire de ces expérimentations a été utilisée afin de construire un premier modèle mathématique permettant d'expliquer la perception globale de la qualité de la stéréoscopie en fonction des paramètres physiques des images étudiée.In a context of ever-growing interest in stereoscopic systems, but where no standardized algorithmic methods of stereoscopic quality assessment exist, our work stands as a step forward in the understanding of the human perception and judgment mechanisms related to the multidimensional concept of stereoscopic image quality. We used a series of tools in order to perform in-depth investigations in this direction: we proposed an adapted framework to structure the process of stereoscopic quality assessment, we implemented a stereoscopic system in our laboratory for performing various tests, we created three stereoscopic datasets with precise structures, and we performed several experimental studies using these datasets. The numerous experimental data obtained were used in order to propose a first mathematical framework for explaining the overall percept of stereoscopic quality in function of the physical parameters of the stereoscopic images under study.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Widening the view angle of auto-multiscopic display, denoising low brightness light field data and 3D reconstruction with delicate details

This doctoral thesis will present the results of my work into widening the viewing angle of the auto-multiscopic display, denoising light filed data the enhancement of captured light filed data captured in low light circumstance, and the attempts on reconstructing the subject surface with delicate details from microscopy image sets. The automultiscopic displays carefully control the distribution of emitted light over space, direction (angle) and time so that even a static image displayed can encode parallax across viewing directions (light field). This allows simultaneous observation by multiple viewers, each perceiving 3D from their own (correct) perspective. Currently, the illusion can only be effectively maintained over a narrow range of viewing angles. We propose and analyze a simple solution to widen the range of viewing angles for automultiscopic displays that use parallax barriers. We insert a refractive medium, with a high refractive index, between the display and parallax barriers. The inserted medium warps the exitant lightfield in a way that increases the potential viewing angle. We analyze the consequences of this warp and build a prototype with a 93% increase in the effective viewing angle. Additionally, we developed an integral images synthesis method that can address the refraction introduced by the inserted medium efficiently without the use of ray tracing. Capturing light field image with a short exposure time is preferable for eliminating the motion blur but it also leads to low brightness in a low light environment, which results in a low signal noise ratio. Most light field denoising methods apply regular 2D image denoising method to the sub-aperture images of a 4D light field directly, but it is not suitable for focused light field data whose sub-aperture image resolution is too low to be applied regular denoising methods. Therefore, we propose a deep learning denoising method based on micro lens images of focused light field to denoise the depth map and the original micro lens image set simultaneously, and achieved high quality total focused images from the low focused light field data. In areas like digital museum, remote researching, 3D reconstruction with delicate details of subjects is desired and technology like 3D reconstruction based on macro photography has been used successfully for various purposes. We intend to push it further by using microscope rather than macro lens, which is supposed to be able to capture the microscopy level details of the subject. We design and implement a scanning method which is able to capture microscopy image set from a curve surface based on robotic arm, and the 3D reconstruction method suitable for the microscopy image set