What is and what is not 360° video: conceptual definitions for the research field

Lionel Roche ^1* Ian Cunningham ² cathy rolland ³

• ¹ Université du Québec à Montréal, Montreal, Canada
• ² Edinburgh Napier University, Edinburgh, United Kingdom
• ³ Clermont Université, Aubière, France

Over the previous years, immersive technologies have been increasingly used in different fields (Suh & Prophet, 2018;Tang et al., 2022). Furthermore, Ranieri et al. (2022) underlined that interest towards the educational use of immersive technologies has grown (p. 1200). Despite this emerging craze, some technologies are not recent and do not constitute a real innovation. Indeed, virtual reality (VR) appeared more than half a century ago as Fuchs and Guitton (2011) pointed out and the term "virtual reality" has been used for more than fifteen years. Indeed, Gigante (1993) recounts Morton Heilig's (1962) design of a multi-sensorial simulator: the Sensorama. This device had all the hallmarks of a VR system, except that it was not interactive, it offered possibility to perceive wind, noise, and smells.In the last decade or so, a new technology has developed in educational settings (Roche et al., 2021): 360° video. However, Snelson and Hsu (2019) pointed out some vagueness in the naming of this technology in the current scientific literature. This definitional vagueness in part due to the novelty of this technological tool but the fact that this field of research is emerging (Snelson & Hsu, 2019), and immature (Paraskevaidis & Fokides, 2020;Reyna Zeballos, 2018).Based on the current literature, the aim of our paper is therefore to propose a circumscribed definition for 360° video so that research on this technology is clearly identified. It is under this premise that we believe it is possible to clearly delineate the boundaries of a research field focused on the uses of 360° video.In the current literature, 360° video is referred to using various terms, which creates definitional ambiguity and complicates the identification of key research findings regarding the uses of this technology. This lack of clarity makes it difficult to pinpoint and compare the main research results within this field. To address this issue, we conducted a narrative review (Baumeister & Leary, 1997) to explore and synthesize the diverse definitions and terminologies used to describe 360° video technology, with a focus on understanding the scope of this ambiguity and its implications for the research field. This type of review approach assists to critically assess how the terms have evolved, and offer a conceptual framework for understanding these terms and their conceptual variations (Grant & Booth, 2009).In conducting this review, we aimed to critically assess the different terms used for 360° video, analyze their conceptual distinctions, and examine how these terms impact the understanding and application of the technology. Rather than mapping all evidence related to 360° video uses, as is typical in a scoping review, the purpose of this narrative review was to focus specifically on how the technology has been defined and named in existing research, and to offer a synthesis of these definitions to establish greater clarity for future studies.To identify the relevant literature, we performed a comprehensive search across six key academic databases: Scopus, ERIC, ScienceDirect, Learntechlib, ProQuest, and PubMed. We conducted multiple iterations of search queries to capture the broad range of terminology used in the literature. The search was not restricted by publication date, ensuring that we captured a diverse selection of articles that contributed to the evolving discourse surrounding 360° video.The search queries included a combination of the following keywords and phrases to capture the various ways 360° video is described:• First query search: "360video OR immersive panoramic video OR panoramic video OR 360VR"• Second query search: "360video OR immersive panoramic video OR panoramic video OR 360VR OR spherical video, spherical video based virtual reality (SVVR)"• Third query search: "360video OR immersive panoramic video OR panoramic video OR 360VRWe also employed a "snowball" technique, in which we examined the citations within the included articles to identify additional relevant sources. This iterative search process continued until no new terms for 360° video emerged, signaling saturation in the terminology identified.In our review, we focused on studies that contributed to the ongoing debate about the terminology and conceptual definitions of 360° video. We included articles that presented or discussed different names and definitions for the technology, whether in academic studies, industry reports, or other relevant publications. After filtering out irrelevant sources, we identified 9 distinct terms used to refer to 360° Once relevant studies were selected, we extracted and synthesized the different definitions and descriptions provided for each of these terms. In cases where visual content (such as illustrations or diagrams) was provided, we screened these to distinguish between literature on 360° video and literature on virtual reality (VR), ensuring that the definitions applied specifically to 360° video. We then summarized the range of terminology used, highlighting the overlap and differences in how the technology is conceptualized across the literature. This research focused on the development of the first cameras capable of capturing panoramic films, marking the starting point for studies on the applications of this technology. In the 2010s, consumer models of omnidirectional cameras emerged, such as the Sony Bloggie (2010), the Ricoh (2013), or the Kodak SP360 (2014). As a result, the name 360° video became more readily available to the public.However, in scientific literature during the same period, the term "spherical video" was also commonly used. For example, Ozkeskin and Tunc (2010) underlined that "spherical videos have the advantage of reflecting the environment as it is" (p. 64). For Yusof et al. (2019), spherical video constitutes a new generation of video that assures bigger acceptance or "immersiveness" compared to traditional video and for Fokides and Kefallinou (2020) this technology "surpass one of the fundamental limitations of regular videos, that of the single point of view, given that they are recorded using cameras able to capture images from a whole sphere. When viewing such videos, the users can freely select, at any given time, which part of the scene to view" (p. 429).In line with spherical videos, it is also possible to identify in the literature the existence of spherical The last name we have identified in the literature is immersive video. In their study for improving decision-making in basketball, Panchuk et al. (2018) used immersive video and stated that it "maintains some of the benefits of VR but is not as resource intensive" (p. 2) because they are based on real images. Rosendahl and Wagner (2023), in line with Roche et al.(2021b), underlined the necessary terminological separation of both technologies of 360° video and VR. For Wohl (2017), 360° video are video recordings in which a view in every direction is recorded at the same time by using a specific camera with a fish-eye lens. Furthermore, Snelson and Hsu (2020) highlights that "ambisonics may also be included for a full sphere surround sound experience" (p. 404). In comparison with VR, this aspect is a specificity of 360° video.Fuchs and Guitton (2011) defined VR as "…a scientific and technical domain that uses computer science (i) and behavioural interfaces (ii) to simulate in a virtual world (iii) the behaviour of 3D entities, which interact in real time (iv) with each other and with one or more users in pseudo-natural immersion (v) via sensorimotor channels" (p. 8). They underlined that VR offer "the possibility of creating computer-generated images in real time and enabling a real-time interaction between the user and the virtual world" (p.6). The purpose of VR is to represent and model human action and a real environment to allow actions and sensory-motor feedback in a virtual world. This is not the case with 360° video.With VR, each person can perceive and act in a virtual world, sometimes with specific devices like head mounted display or haptic gloves. VR is characterized by "the illusion of participation in a synthetic environment rather than external observation of such an environment" (Gigante, 1993, p. 3).VR can be defined based on three main dimensions: (i) computer-generated, (ii) three-dimensional, and (iii) interactive (Bryson, 1996). For Wohlgenannt et al. (2020), VR is based on three main properties: presence (i.e., feeling of being physically somewhere other than where one actually is), interactivity (i.e., users can manipulate their virtual environment in real time), and immersion (i.e., characterized by different dimensions like cognitive immersion, emotional immersion, sensorymotoric immersion and spatial immersion). Unlike VR, 360° video is not interactive, she doesn't offer the possibility to interact with the environment or objects in the video. Furthermore, Lee et al. (2022) pointed out that 360° video "does not allow the viewer to walk in a VR environment" (p. 310), the spectator "is not able to move through the space in which the scene was filmed" (Vosmeer & Schouten, 2014, p. 144). This is because this technology offers only 3 degrees of freedom (DoF) and VR 6 DoF (Griffin et al., 2021). With 360° videos the user can freely choose his viewing angle in a 360° angle around the camera but it's not possible to move in the filmed scene (Table 1). Finally, if some studies (Araiza-Alba et al., 2021;Rosendahl & Wagner, 2023) have been able to underline that 360° videos can be viewed with low (on desktop) or high immersive devices (HMD), the use of VR headset can maintain trouble about the definition of this technology. However, it is reductive to consider that 360° video would be immersive and would generate a feeling of presence only if they are viewed with an HMD. Indeed, some studies have shown that viewing on a desktop could also generate a feeling of presence and immersion (Roche et al., 2021a). Furthermore, the adjective "immersive" does not constitute a technical characteristic of the audiovisual material but refers to the potential experience that a user may have in a viewing situation. While some studies aim to characterize these user experiences in a variety of situations, we feel it would be more coherent and prudent not to declare videos to be immersive a priori.We hope that our contribution will help stabilize a unified definition of 360° video and improve the organization of the research field related to this technology, thereby enabling a clearer identification of all research findings in this area.