• KIPS Transactions on Software and Data Engineering
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• v.6 no.12
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• pp.581-586
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• 2017

This paper proposes a GPU based water surface animation and rendering technique for interactive applications such as games. On the water surface, a lot of physical phenomenon occurs including reflection and refraction depending on the viewing direction. When we represent the water surface, not only showing them in real time, but also make them adjusted automatically. In our implementation, we are able to capture the reflection and refraction through render-to-texture technique and then modify the texture coordinates for applying separate DU/DV map. Also, we make the amount of ratio between reflection and refraction change automatically based on Fresnel formula. All proposed method are implemented using OpenGL 3D graphics API.

• Korean Journal of Computational Design and Engineering
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• v.8 no.2
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• pp.65-74
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• 2003

For virtual reality, virtual manufacturing system, or simulation based design, we need to visualize very large and complex 3D models which are comprising of very large number of polygons. To overcome the limited hardware performance and to attain smooth realtime visualization, there have been many researches about algorithms which reduce the number of polygons to be processed by graphics hardware. One of these algorithms, occlusion culling is a method of rejecting the objects which are not visible because they are occluded by other objects, and then passing only the visible objects to graphics hardware. Existing occlusion culling algorithms have some shortcomings such as the required long preprocessing time, the limitation of occluder shape, or the need for special hardware implementation. In this study, an efficient occlusion culling algorithm is proposed. The proposed algorithm reads and analyzes Z-buffer of graphics hardware using Microsoft DirectX, and then determines each object's visibility. This proposed algorithm can speed up visualization by reading Z-buffer using DirectX which can access hardware directly compared to OpenGL, by reading only the region to which each object is projected instead of reading the whole Z-Buffer, and the proposed algorithm can perform more exact visibility test by using simplified model instead of using bounding box. For evaluation, the proposed algorithm was applied to very large polygonal models. And smooth realtime visualization was attained.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.229-232
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• 2009

In this paper, we propose a new programmable shader architecture based on an effective ALU operation. Today's mobile devices need the programmable shader processor for a three-dimensional(3D) graphics. The programmable shader processors require a lager ALU than a fixed pipeline ALU used previously. The proposed ALU architecture is able to execute two different arithmetic operations at the same time. Two instructions which need exclusive ALU operations are inserted into instruction decoders in parallel. Experimental results show the number of instruction cycles can be substantially reduced up to 40%.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.171-176
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• 2013

X-ray cross-sectional image-based inspection technique is one of the most useful methods to inspect the brazing joints of heat exchanger. Through X-ray cross-sectional image acquisition, image processing, and defect inspection, the defects of brazing joints can be detected. This paper presents a method to judge the type of detected defects automatically, and to display them three-dimensionally. The defect type is classified as unconnected defect, void, and so on, based on location, size, and shape information of defect. Three-dimensional display which is realized using OpenGL (Open Graphics Library) will be helpful to understand the overall situation including location, size, shape of the defects in a test object.

• Journal of Broadcast Engineering
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• v.27 no.3
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• pp.341-350
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• 2022

In this paper, we propose a deep learning based on-device augmented reality (AR) system in which multiple input images are used to implement the correct occlusion in a real environment. The proposed system is composed of three technical steps; camera pose estimation, depth estimation, and object augmentation. Each step employs various mobile frameworks to optimize the processing on the on-device environment. Firstly, in the camera pose estimation stage, the massive computation involved in feature extraction is parallelized using OpenCL which is the GPU parallelization framework. Next, in depth estimation, monocular and multiple image-based depth image inference is accelerated using the mobile deep learning framework, i.e. TensorFlow Lite. Finally, object augmentation and occlusion handling are performed on the OpenGL ES mobile graphics framework. The proposed augmented reality system is implemented as an application in the Android environment. We evaluate the performance of the proposed system in terms of augmentation accuracy and the processing time in the mobile as well as PC environments.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.954-959
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• 2006

Virtual Reality simulation enables immersive 3D experience of a Virtual Environment. A simulation-based VE can be used to map real world phenomena into virtual experience. This research studies on the use of Newton's physics law to demonstrate the effects of forces upon object's falling movement, and their effects towards other fallible objects. A reconfigurable simulation enables users to reconfigure the parameters of the objects involved in the simulation, so that they can see different effects from the different configurations, such as force magnitude and distance between objects. This concept is suitable for a classroom learning of physics law. Preliminary implementation is done on a PC with a joystick for 4DOF movement. The graphics is implemented by SGI OpenGL Performer. A middleware called NAVERLib that consists of Performer's modules for easy XML-based configuration is used for management of visualization, network and devices connection, and where the engine of this domino simulation is attached.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.4
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• pp.181-187
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• 2001

본 논문에서는 3D 텍스쳐 매핑 하드웨어(texture mapping hardware)하에서 OpenGL를 이용하여 빠른 추출(classification) 및 음영처리(shading)를 가능하게 하는 직접 볼륨 렌더링(direct volume rendering) 방법을 제안한다. 추출과정을 위해 lookup table을 통해서 볼륨 데이터의 밀도값(density)으로부터 불투명도(opacity)값을 얻어내고, 법선 벡터 블렌딩(normal blending)방법을 제안하여 볼륨 크기에 상관없이 최종 이미지에서만 음영 처리 연산을 수행한다. 본 논문에서 제시된 볼륨 렌더링의 전과정이 그래픽스 하드웨어(graphics hardware)에서 이뤄지면, 음영처리 연산의 복잡도 감소로 인하여 상호 대화적인 볼륨 렌더링이 가능하다.

• Electronics and Telecommunications Trends
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• v.21 no.1 s.97
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• pp.35-43
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• 2006

X 서버는 개발된 지 20년 동안 그리 큰 변경이 이루어지지 않았다. 하지만, 그래픽 하드웨어는 사양은 3D 그래픽 고성능으로 변화되었다. X 서버는 2D 그래픽을 처리하기위한 그래픽 시스템으로 설계되었다. 3D 그래픽 처리를 위해서 OpenGL 라이브러리를X 서버와 연동하는 작업을 해왔지만 구조적으로 3D 그래픽 드로잉을 처리하는 것은 X서버이기 때문에 성능에 한계를 드러내게 되었다. 마이크로소프트사 DirectX 구조처럼직접 그래픽 하드웨어를 제어해서 3D 그래픽 처리를 구현하고 있으며 리눅스 진영은X 서버와 공존하면서 3D 그래픽 처리를 향상시키기 위한 연구를 진행하고 있다. 본 고에서는 리눅스 진영에서 현재 진행중인 향상된 3D 그래픽 처리에 대한 기술 동향을 설명한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1888-1896
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• 2002

This study presents a new type of CNC interpolator that is capable of generating cutter paths for ball-end milling of NURBS surfaces. The proposed surface interpolator comprises real-time algorithms for cutter contact (CC) path scheduling and CC path interpolator. Especially in this study, a new interpolator module to regulate cutting forces is developed. This propose algorithm utilizes variable-feedrate commands along the CC path according to the curvature of machined surfaces during the interpolation process. Additionally, it proposes an OpenGL graphic library for computer graphics and animation of interpolated tool-position display. The proposed interpolator is evaluated and compared with the existing method based on constant feedrates through computer simulations.

• 한국전산유체공학회:학술대회논문집
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• 1999.11a
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• pp.145-151
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• 1999

An Interactive grid generation program(KGRID) with graphical user interface(GUI) has been improved. KGRID works on the UNLX environment and GUI has been implemented with OSF/Motif and X Toolkit and the graphics language is Open GL for visualization of the 3D objects. It supports more convenient user environment to generate 2D and 3D multi-block structured grid systems. It provides various useful field grid generation methods, which are the algebraic methods, the elliptic partial differential equations method and the predictor-corrector method. It also supports 3D surface grid generation with NURBS(Non-Uniform Rational B-Spline) and various stretching functions to control grid points distribution on curves and surfaces. And some menus are added to perform flexible management, for the objects. We generated surface and field grid system about full aircraft configuration using KGRID. The performance and stability of the KGRID is verified through the generation of the grid system about a complex shape.