## 1 Introduction  
Several recent publications have demonstrated the use of inside-out multi-view capture to generate photorealistic 360 deg scenes for virtual reality (VR). In particular, such capture setups can be used to effectively recreate the captured scene in all directions, even as users move their head within a viewing volume of several tens of centimeters [1, 2]. Additionally, various authors have shown how photographs taken from multiple different viewpoints can be used to accurately recover complex view-dependent effects such as specular highlights, in order to replicate the way light interacts with reflective and semi-transparent objects in real life [1, 3, 4, 5, 6]. In this way, such methods aim to make scenes rendered from photographs more realistic. However, these approaches also have drawbacks: most notably, they often generate visual inaccuracies such as flickering or ghosting artifacts (visual data from one object appearing on top of the surrounding objects during blending due to errors in the geometry), and may thus be distracting or disturbing for immersed viewers [1]. With this in mind, we believe that it is important to investigate how immersed viewers effectively respond to effects such as the display of view-dependent highlights and the presence of distracting visual artifacts, and in particular how this may impact their appreciation of the scene's realism. Few existing user studies have examined this question. Additionally, because the input photographs are captured around a given viewpoint, the accuracy of the rendered views diminishes the more users move away from the viewpoint. Consequently, several approaches make the scene fade out beyond a fixed range of head motion [1; 7]. However, it seems reasonable to assume that making the scene disappear in this way may cause users to feel like they are not actually there, visiting the recreated place, as the scene is thereby likely to feel intangible, fleeting, ephemeral. Therefore, we hypothesize that such limited viewing volumes are likely to cause a significant decrease in what is often referred to in the literature as the sense of presence [8; 9; 10] or place illusion [9]--that is, the sensation of being in a real place, of \"being there\" [8; 9; 10]. If this is indeed the case, it may thus be preferable instead to remove this fade effect, in spite of the decrease in visual accuracy as one moves away from the center. Similarly, few existing studies seem to address this question of how having to restrict the viewing volume (due to the virtual environment being created from photographs centered around a given viewpoint) may potentially impact users' sense of presence. Therefore, in this paper we propose a user-centered evaluation of virtual reality environments created from inside-out multi-view capture systems. Specifically, we lead a user study to evaluate two hypotheses. First, we test the assumption that immersive environments capable of replicating view-dependent highlights are likely to be perceived by users as being more visually realistic than standard alternatives that blur out these highlights, despite the likely creation of visual artifacts. Second, we test the hypothesis that making the scene fade out beyond a small distance (several tens of centimeters) away from the central viewpoint is likely to cause a significant decrease in users' sense of presence. We believe that both of these questions are important, as they may provide valuable insight on how the size of the capture volume and the choice of a rendering method may make the immersive experience seem more realistic and provide a stronger sense of being transported in the recreated location. Consequently, we make the following contributions in this paper:  
* We provide an overview of the challenges and opportunities linked to capturing and rendering real-world scenes using multi-view setups. We notably discuss how we applied this analysis to recreate a museum gallery in VR (see Figure 1 for an illustration of the results) using a custom outward-facing multi-camera rig.