Integrating Live Video for Immersive Environments

projection display, is a room-sized, five-screen system that can display both computer graphics and video images. Several Cabins connected via a broadband network form the Cabinet system. Cabinet includes video avatars—a key new technology for sharing virtual worlds. Using video avatars, we have experimentally evaluated the ability to express positional information between distant users. I mmersive projection technology (IPT) has become a popular virtual reality display system. 1 Many projection-based displays such as the Cave Automatic Virtual Environment (CAVE) and C2 are currently used at various research institutes worldwide. 2-5 This kind of display can provide a wide field of view and high-resolution stereo images to multiple persons. In 1997, the Intelligent Modeling Laboratory (IML) at the University of Tokyo developed Cabin (Computer Augmented Booth for Image Navigation) as an extended immersive projection display system. 6 Cabin is a room-sized, five-screen display for both computer graphics images and video images. In 1997, we extended this IPT to a networked environment by connecting Cabin to other immersive projection displays, such as CoCabin research project, called Cabinet, aims to share distant virtual 3D spaces based on computer graphics images and video images by using networked immersive projection displays. Overview of Cabin We designed Cabin's physical structure and features to facilitate display of both computer graphics and video images, as follows. Five-screen configuration Cabin has five stereo screens—one at the front and one each on the left, right, ceiling, and floor. Figure 1 shows the external appearance, and Figure 2 shows the structure of Cabin. The display space is 2.5m × 2.5m × 2.5m. Its raised frame lets all screens be rear-projected. A magnetic sensor (Polhemus Ultratrak Pro) tracks the position and orientation of the viewer's head, and 3D images from the user's viewpoint are projected onto the five screens using Electrohome Marquee 8500 stereo projectors. Because of the five-screen configuration, Cabin provides stereo images with an extremely wide field of view (FOV). Consequently, it effectively synthesizes a life-sized immersive VR world. Tempered glass screen To construct the five-screen configuration, we first had to address several problems. The floor screen must support the viewers' weight. In the case of CAVE, which has no ceiling screen, the floor screen image can be front-projected from the ceiling. However, with Cabin, since both the ceiling and floor screens are rear-projected, the floor structure must support users standing on the rear-projected screen. Also, the interface design between …