Browsing by Author "Kim, Jaedong"

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    Real-time Content Projection onto a Tunnel from a Moving Subway Train
    (The Eurographics Association, 2021) Kim, Jaedong; Eom, Haegwang; Kim, Jihwan; Kim, Younghui; Noh, Junyong; Lee, Sung-Hee and Zollmann, Stefanie and Okabe, Makoto and Wünsche, Burkhard
    In this study, we present the first actual working system that can project content onto a tunnel wall from a moving subway train so that passengers can enjoy the display of digital content through a train window. To effectively estimate the position of the train in a tunnel, we propose counting sleepers, which are installed at regular interval along the railway, using a distance sensor. The tunnel profile is constructed using pointclouds captured by a depth camera installed next to the projector. The tunnel profile is used to identify projectable sections that will not contain too much interference by possible occluders. The tunnel profile is also used to retrieve the depth at a specific location so that a properly warped content can be projected for viewing by passengers through the window when the train is moving at runtime. Here, we show that the proposed system can operate on an actual train.
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    Real‐Time Human Shadow Removal in a Front Projection System
    (© 2019 The Eurographics Association and John Wiley & Sons Ltd., 2019) Kim, Jaedong; Seo, Hyunggoog; Cha, Seunghoon; Noh, Junyong; Chen, Min and Benes, Bedrich
    When a person is located between a display and an operating projector, a shadow is cast on the display. The shadow on the display may eliminate important visual information and therefore adversely affect the viewing experiences. There have been various attempts to remove the human shadow cast on a projection display by using multiple projectors. While previous approaches successfully removed the shadow region when a person moderately moves around or stands stationary in front of the display, there is still an afterimage effect due to the lack of consideration of the limb motion of the person. We propose a new real‐time approach to removing the shadow cast by a person who dynamically interacts with the display, making limb motions in a front projection system. The proposed method utilizes a human skeleton obtained from a depth camera to track the posture of the person which changes over time. A model that consists of spheres and conical frustums is constructed based on the skeleton information in order to represent volumetric information of the person being tracked. Our method precisely estimates the shadow region by projecting the volumetric model onto the display. In addition, employment of intensity masks that are built based on a distance field helps suppress the afterimage of the shadow that appears when the person moves abruptly. It also helps blend the projected overlapping images from different projectors and show one smoothly combined display. The experiment results verify that our approach removes the shadow of a person effectively in a front projection environment and is fast enough to achieve real‐time performance.