Copyright is held by the author/owner. CSCW ’08, November 8-12, 2008, San Diego, California, USA t-Room: Remote Collaboration Apparatus Enhancing Spatio-Temporal Experiences Keiji Hirata, Katsuhiko Kaji, Yasunori Harada, Naomi Yamashita, Shigemi Aoyagi NTT Communication Science Laboratories 2-4, Hikaridai, Seika-cho, "Keihanna Science City", Kyoto 619-0237, Japan {hirata,hara,aoyagi}@brl.ntt.co.jp, {kaji,naomi}@cslab.kecl.ntt.co.jp ABSTRACT In this paper, we describe the overall design of the remote collaboration apparatus t-Room and present three applications: playback of a recorded scene using a hand controller, an elevator effect at scene change, and remote golf lessons. These applications are realized by the high controllability and flexibility of the t-Room system, and they can provide the user with a novel type of spatio- temporal experience. Author Keywords Presence Disparity, Surrounding Back Screen, Video- Mediated Communication. ACM Classification Keywords H5.2 [Information interfaces and presentation]: User Interfaces. - Prototyping. INTRODUCTION We are developing the video collaboration system t-Room using shared video screens [2,8]. Our aim is to help users overcome spatial and temporal barriers in collaborative communication and, furthermore, use t-Room as a medium for content production. Systems employing a shared video screen method include VideoDraw [7], ClearBoard [3], Agora [4], and VideoArms [6]. However, these systems merely project a part of a scene or perspective in a room to the screens of the other rooms, so the reciprocity of perspective [1] does not hold (i.e., the presence-disparity problem occurs [6]). To resolve this problem, t-Room encloses a user space with surrounding large LCD displays showing life-sized images. The enclosed space is shared with other enclosed spaces by overlapping it onto them. Moreover, with this setup, t- Room can preserve the spatial relationships existing between moving people and objects (i.e., spatial cues). In addition, by introducing recording and playback capabilities of the activities that occur within the entire space, t-Room allows asynchronous communication to overcome temporal barriers, in the manner of e-mail, blogs, telephone answering machines, and video submission sites [5]. In the asynchronous communication, a referencing (e.g., quotations in e-mail and citations in blogs) realized by the recording and playback capabilities plays a significant role for facilitating interactivity across time. So, we expect that the combination of surrounding shared video screens and the recording and playback capabilities may lead to a novel type of spatio-temporal experience that can be used, for example, in content production with non-verbal skills. T-ROOM ARCHITECTURE Figure 1 illustrates our method for reproducing face-to-face interaction among persons A, B, and C; we duplicate a space and project remote users’ images to surrounding back screens [2]. For each room, we alternatively arrange three screens and three cameras to surround a user, who stands just in front of a screen. The preprocessing denoted by --- and ++ in the figure is needed. The function of --- is to extract only the light from real objects in front of the opposite screen and to cancel the light from the screen (visual echo canceller). That of ++ is to overlap or superimpose more than two images captured in Rooms 1 Figure 1: Duplicating space and projecting images to surrounding back screen A’s Room 2 Person B C’s image Recording & Playback Room 3 B’s image Room 1 Video Camera Screen + Person A Person C + +