Light field displays offer glasses-free 3D visualization, which means that multiple individuals may observe the same content simultaneously from a virtually infinite number of perspectives without the need of viewing devices. The practical utilization of such visualization systems include various passive and active use cases. In the case of the latter, users often engage with the utilized system via human–computer interaction. Beyond conventional controls and interfaces, it is also possible to use advanced solutions such as motion tracking, which may seem seamless and highly convenient when paired with glasses-free 3D visualization. However, such solutions may not necessarily outperform conventional controls, and their true potentials may fundamentally depend on the use case in which they are deployed. In this paper, we provide a review on the 3D interaction of light field displays. Our work takes into consideration the different requirements posed by passive and active use cases, discusses the numerous challenges, limitations and potentials, and proposes research initiatives that could progress the investigated field of science.

The past decades have shown a steady rise in the pixel resolution of digital visualization technologies. New TVs and computer displays available on the consumer market are commonly UHD/4K, and 8K recently started appearing in the commercial world. The added value of such higher resolution is not only indicated by the purported level of visual performance, but also by the labels that emphasize the devices’ properties, especially the resolution. However, the genuinely perceived difference between two resolutions, such as HD and UHD, may not have the same effect on user experience as the labels attached to the devices or sequences themselves. In this paper we present four subjective studies in which we investigated the influence of the labeling effect in the context of HD and UHD video. Subjects were shown pairs of either HD or UHD video sequences and had to determine whether there was a difference in quality between the sequences. Two of the subjective tests involved labels in these paired comparisons, indicating to the subject which sequence was which, while the other two tests excluded these labels. For both test sets with and without labels, one test used a 3-point comparison scale for the subjective assessment of visual quality, while the other used a more fine-grained 7-point scale. Our findings show that the sole inclusion of quality labels can strongly impact subjective rating behavior and the overall opinion on UHD quality; also, visual differences between HD and UHD video were rarely noticeable by the subjects.

With the upcoming emergence of the IEEE P3333.1.4 standard, the first ever standardization document on the subjective quality assessment of light field visualization, we are approaching a major milestone of light field Quality of Experience (QoE). The research efforts leading up to this point have answered the fundamental questions regarding perceptual thresholds and personal preference, and best practices regarding research methodologies have been formed. However, in order to introduce successful and efficient light field systems and services, research questions beyond perceptual thresholds and personal preference must be addressed, along with the associated methodologies. In this paper, we propose a comprehensive set of novel research questions and methodologies regarding light field QoE. Our work also provides a detailed discussion of related factors, particularly those that extend to test participants and thus may affect the results of subjective studies.

At the time of this paper, high dynamic range (HDR) visualization has already emerged in both the industry and the commercial sector, with HDR displays already present on the consumer market and the technology marching towards the goal of becoming the de facto format of multimedia. HDR is thus often looked at and praised as the next logical step in the evolution of audiovisual entertainment. However, there is no such thing as a single, universal HDR standard, and the competing market projects a future with even more diversity in format specifications, display capabilities and content characteristics. As the competitors attempt to surpass each other and obtain a bigger share of the global market, they inevitably bombard the potential customers and users with brief but effective labels that reflect excellence and superior quality. In this paper, the cognitive effect of such labels is investigated. As home video entertainment is possibly the most numerous instance of the future usage of this visualization technology, video streaming is particularly addressed. Since real-time video transmission services are bound to suffer playback interruptions upon insufficient data rates and uncompensated drops in the available bandwidth, stalling events experienced in conventional multimedia streaming shall apply to HDR video as well. The paper presents four separate experiments, studying how the cognitive bias caused by the labeling effect influences the perception of HDR quality aspects and stalling events, and how the cognitive load varies for stalling detection thresholds between conventional and HDR visualization.