As the research efforts and development processes behind light field visualization technologies advance, potential novel use cases emerge. These contexts of light field display utilization fundamentally depend on the distance of observation, due to the sheer technological nature of such glasses-free 3D systems. Yet, at the time of this paper, the number of works in the scientific literature that address viewing distance is rather limited, focusing solely on 3D visual experience based on angular density. Thus far, the personal preference of observers regarding viewing distance has not been considered by studies. Furthermore, the upcoming standardization efforts also necessitate research on the topic in order to coherently unify the methodologies of subjective tests. In this paper, we investigate the perceptually-supported and the subjectively-preferred viewing distance of light field visualization. We carried out a series of tests on multiple projection-based light field displays to study these distances, with the separate involvement of experts and regular test participants.
Light field visualization is an emerging 3D technology that does not rely on viewing devices, such as special glasses. Without the need for such additional devices, multiple users may simultaneously enjoy the glasses-free 3D experience from a virtually infinite number of viewing positions, as the motion parallax is continuous and smooth. Although this immensely valuable property of light field displays does enable a great deal of viewing freedom, the proper perception of the visualized content still depends on the position of the observer. Position in this context determines the distance and the angle of the observer, with respect to the screen of the display. The validity of the latter is relatively straightforward to assess: if the observer is viewing the screen from inside the angle set by the field of view of the display, then the content shall be seen from its perceptually correct angle. However, the fundamental issue with the underinvestigated topic of viewing distance is that light field visualization may lose its 3D nature if viewed from a far-away position. This is due to the fact that in such a case, a single point of the screen may emit identical rays of light towards the two pupils of the observer. Therefore, the deficiency of disparity, the lack of distinct rays may lead to a 2D visual experience, nullifying the core scientific contribution of this technology. Of course, moving sideways in front of a horizontal-only-parallax display may, in fact, induce a 3D experience via the natural sense of parallax, but it should be applicable regardless of movement. Needless to say, in a multitude of professional environments, the users of such displays are not expected to be highly mobile during the work-related utilization of the technology. However, at the time of this paper, merely a few publications of the scientific literature address the topic of viewing distance, and standardization efforts are still in a rather early phase. Summa summarum, light field displays need clear guidelines with regard to viewing distance, which may benefit both the manufacturers and the users. Such guiding principles may make development and production more cost-efficient and user-oriented, and may contribute to the increased efficiency of usage-focused display design. In this paper, we provide a series of recommendations on the viewing distance of light field displays. The displays are separately analyzed within the context of their own use cases, taking into account the key performance indicators of both the apparatus and the visualized content, the various environmental conditions, as well as the relevant use-case-scenario-specific necessities and the professional requirements. The investigated use cases include medical imaging, telepresence, resource exploration, prototype review, training and education, gaming, digital signage, cinematography, cultural heritage exhibition, air traffic control and driver assistance systems.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.