Byounghyun Yoo, Don Brutzman, in preparation.

Byounghyun Yoo, Soonhung Han, IEEE Transactions on Visualization and Computer Graphics, in review.

Abstract:

This paper introduces a displacement mapping technique which represents protruded shapes on the
surface of an object. Previous approaches for the image-based displacement mapping can represent
only shapes depressed from a polygon surface. The proposed technique can represent shapes such as
tall buildings protruding from the underlying surface. Two auxiliary surfaces that are perpendicular
to the underlying surface are added along the boundary of the polygon surface in order to represent
pixels overflowing the boundary of the polygon surface. The proposed approach can accurately represent
the silhouettes of protruded shapes. Furthermore, both smooth displacement of protruded shapes and
abrupt displacement such as perpendicular protrusion by means of adding the supplementary texture
information to the steep surface of the protruded shape can be represented. Using per-pixel instructions
on a programmable GPU, this approach can be executed in real-time. Overall, the proposed method
provides an effective solution for the representation of protruding shapes such as high-rise buildings in
an urban environment which can be used in GIS and VR applications.

Keywords: building representation, image-based rendering, motion parallax, protruded shape representation,
silhouette management, displacement mapping

Pilwon Hur, Soonhung Han, Jungsam Yang, Byounghyun Yoo, Simulation: Transactions of The Society for Modeling and Simulation International, 85(1), pp.33-44, 2009.

Abstract:

Training war fighters how to maneuver a submarine is very important, but the use of real submarines in such training is expensive and hindered by regional and temporal limitations. Modeling and simulation (M&S) can be a good alternative to costly training. However, the use of existing M&S for submarines has limitations. For instance, the commercial software and hardware need to be kept in a secure place. Depending on the location of the protected software, war fighters may travel far and take a considerable time to get to these places. Long-distance travel also means they have a limited amount of time to train on the M&S machines. Furthermore, many types of M&S have only a one-channel display system, which reduces immersiveness. Another problem is that few heterogeneous simulators can be used as an integrated system. One solution to these problems involves the use of X3D, a platform-independent and open standard graphic file format, which can be used with general-purpose PCs. The immersiveness is increased by means of a multichannel display system and a motion chair. Finally, the individual components of a simulator can be integrated with the high level architecture and run time infrastructure (HLA/RTI). We demonstrate the proposed method through experiments with an underwater vehicle simulator.

Keywords: high level architecture (HLA), modeling and simulation, motion chair, multichannel, extensible 3D (X3D) graphics

DOI: 10.1177/0037549708101180

Byounghyun Yoo, Soonhung Han, Transactions in GIS, 10(3), pp.377-394, 2006.

Abstract:

A VR (virtual reality) simulator which is used for helicopter simulations requires a virtual environment of real world urban areas. However, real urban environments are continuously changing. It is necessary to develop a modeling method that makes direct use of GIS (geographical information system) data which is updated periodically. A flight simulation needs to visualize not only buildings in the near distance but also a large number of buildings in the far distance. We propose a method for modeling urban environments from aerial images and digital maps with relatively little manual work. An image-based method is applied to the urban modeling that considers the characteristics of Korean cities. Buildings in the distance can be presented without creating a large number of polygons. The proposed method consists of a pre-processing stage that prepares the model from the GIS data and a modeling stage that creates the virtual urban environment. The virtual urban environment utilizes the height map of buildings.

DOI: 10.1111/j.1467-9671.2006.01003.x

Byounghyun Yoo, Soonhung Han, Journal of Computer Science and Technology, 21(2), pp.204-208, 2006.

Abstract:

This paper describes the real-time mapping displacement of buildings onto the polygon model of base terrain of geo-spatial information. The buildings are represented as height maps, leading to low memory requirements and not involving changes of the original geometry (i.e., no vertices are created or displaced). The displacement of buildings is mapped toward the protruding direction. The base of texture which represents the ground in topography is correctly mapped onto base polygon without any distortion. This approach can exhibit the correct occlusions between buildings and ground due to parallax and correct self-occlusion.

Keywords: aerial photograph, digital map, displacement mapping, geo-visualization, image-based rendering

DOI: 10.1007/s11390-006-0204-8