Testing QoE in Different 3D HDTV Technologies

The three dimensional (3D) display technology has started flooding the consumer television market. There is a number of different systems available with different marketing strategies and different advertised advantages. The main goal of the experiment described in this paper is to compare the systems in terms of achievable Quality of Experience (QoE) in different situations. The display systems considered are the liquid crystal display using polarized light and passive lightweight glasses for the separation of the left- and right-eye images, a plasma display with time multiplexed images and active shutter glasses and a projection system with time multiplexed images and active shutter glasses. As no standardized test methodology has been defined for testing of stereoscopic systems, we develop our own approach to testing different aspects of QoE on different systems without reference using semantic differential scales. We present an analysis of scores with respect to different phenomena under study and define which of the tested aspects can really express a difference in the performance of the considered display technologies

Methods for reducing visual discomfort in stereoscopic 3D: A review

This work was supported by the EPSRC Grant EP/M01469X/1, “Geometric Evaluation of Stereoscopic Video”

Crosstalk in stereoscopic displays: A review

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

3D video quality of experience - influence of scale and crosstalk

This paper gives an overview of three recent studies by the authors on the topic of 3D video Quality of Experience (QoE). Two of studies [1,2] investigated different psychological dimension that may be needed for describing 3D video QoE and the third the visibility and annoyance of crosstalk[3]. The results shows that the video quality scale could be sufficient for evaluating S3D video experience for coding and spatial resolution reduction distortions. It was also confirmed that with a more complex mixture of degradations more than one scale should be used to capture the QoE in these cases. The study found a linear relationship between the perceived crosstalk and the amount of crosstalk

Measurement of crosstalk in stereoscopic display systems used for vision research

Studying binocular vision requires precise control over the stimuli presented to the left and right eyes. A popular technique is to segregate signals either temporally (frame interleaving), spectrally (using coloured filters) or through light polarization. None of these segregation methods achieves perfect isolation, and so a degree of ‘crosstalk’ is usually apparent in which signals intended for one eye are faintly visible to the other eye. Previous studies have reported crosstalk values mostly for consumer-grade systems. Here we measure crosstalk for eight systems, many of which are intended for use in vision research. We provide benchmark crosstalk values, report a negative crosstalk effect in some LCD-based systems, and give guidelines for dealing with crosstalk in different experimental paradigms

A Programmable Display-Layer Architecture for Virtual-Reality Applications

Two important technical objectives of virtual-reality systems are to provide compelling visuals and effective 3D user interaction. In this respect, modern virtual reality system architectures suffer from a number of short-comings. The reduction of end-to-end latency, crosstalk and judder are especially difficult challenges, each of which negatively affects visual quality or user interaction. In order to provide higher quality visuals, complex scenes consisting of large models are often used. Rendering such a complex scene is a time-consuming process resulting in high end-to-end latency, thereby hampering user interaction. Classic virtual-reality architectures can not adequately address these challenges due to their inherent design principles. In particular, the tight coupling between input devices, the rendering loop and the display system inhibits these systems from addressing all the aforementioned challenges simultaneously. In this thesis, a virtual-reality architecture design is introduced that is based on the addition of a new logical layer: the Programmable Display Layer (PDL). The governing idea is that an extra layer is inserted between the rendering system and the display. In this way, the display can be updated at a fast rate and in a custom manner independent of the other components in the architecture, including the rendering system. To generate intermediate display updates at a fast rate, the PDL performs per-pixel depth-image warping by utilizing the application data. Image warping is the process of computing a new image by transforming individual depth-pixels from a closely matching previous image to their updated locations. The PDL architecture can be used for a range of algorithms and to solve problems that are not easily solved using classic architectures. In particular, techniques to reduce crosstalk, judder and latency are examined using algorithms implemented on top of the PDL. Concerning user interaction techniques, several six-degrees-of-freedom input methods exists, of which optical tracking is a popular option. However, optical tracking methods also introduce several constraints that depend on the camera setup, such as line-of-sight requirements, the volume of the interaction space and the achieved tracking accuracy. These constraints generally cause a decline in the effectiveness of user interaction. To investigate the effectiveness of optical tracking methods, an optical tracker simulation framework has been developed, including a novel optical tracker to test this framework. In this way, different optical tracking algorithms can be simulated and quantitatively evaluated under a wide range of conditions. A common approach in virtual reality is to implement an algorithm and then to evaluate the efficacy of that algorithm by either subjective, qualitative metrics or quantitative user experiments, after which an updated version of the algorithm may be implemented and the cycle repeated. A different approach is followed here. Throughout this thesis, an attempt is made to automatically detect and quantify errors using completely objective and automated quantitative methods and to subsequently attempt to resolve these errors dynamically

Stereo Viewing and Virtual Reality Technologies in Mobile Robot Teleguide

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.” DOI: 10.1109/TRO.2009.2028765The use of 3-D stereoscopic visualization may provide a user with higher comprehension of remote environments in teleoperation when compared with 2-D viewing, in particular, a higher perception of environment depth characteristics, spatial localization, remote ambient layout, faster system learning, and decision performance. Works in the paper have demonstrated how stereo vision contributes to the improvement of the perception of some depth cues, often for abstract tasks, while it is hard to find works addressing stereoscopic visualization in mobile robot teleguide applications. This paper intends to contribute to this aspect by investigating the stereoscopic robot teleguide under different conditions, including typical navigation scenarios and the use of synthetic and real images. This paper also investigates how user performance may vary when employing different display technologies. Results from a set of test trials run on seven virtual reality systems, from laptop to large panorama and from head-mounted display to Cave automatic virtual environment (CAVE), emphasized few aspects that represent a base for further investigations as well as a guide when designing specific systems for telepresence.Peer reviewe

Phenomenal regression as a potential metric of veridical perception in virtual environments

It is known that limitations of the visual presentation and sense of presence in a virtual environment (VE) can result in deficits of spatial perception such as the documented depth compression phenomena. Investigating size and distance percepts in a VE is an active area of research, where different groups have measured the deficit by employing skill-based tasks such as walking, throwing or simply judging sizes and distances. A psychological trait called phenomenal regression (PR), first identified in the 1930s by Thouless, offers a measure that does not rely on either judgement or skill. PR describes a systematic error made by subjects when asked to match the perspective projections of two stimuli displayed at different distances. Thouless’ work found that this error is not mediated by a subject’s prior knowledge of its existence, nor can it be consciously manipulated, since it measures an individual’s innate reaction to visual stimuli. Furthermore he demonstrated that, in the real world, PR is affected by the depth cues available for viewing a scene. When applied in a VE, PR therefore potentially offers a direct measure of perceptual veracity that is independent of participants’ skill in judging size or distance. Experimental work has been conducted and a statistically significant correlation of individuals’ measured PR values (their ‘Thouless ratio’, or TR) between virtual and physical stimuli was found. A further experiment manipulated focal depth to mitigate the mismatch that occurs between accommodation and vergence cues in a VE. The resulting statistically significant effect on TR demonstrates that it is sensitive to changes in viewing conditions in a VE. Both experiments demonstrate key properties of PR that contribute to establishing it as a robust indicator of VE quality. The first property is that TR exhibits temporal stability during the period of testing and the second is that it differs between individuals. This is advantageous as it yields empirical values that can be investigated using regression analysis. This work contributes to VE domains in which it is desirable to replicate an accurate perception of space, such as training and telepresence, where PR would be a useful tool for comparing subjective experience between a VE and the real world, or between different VEs