• Journal of Biomedical Engineering Research
• /
• v.12 no.2
• /
• pp.79-88
• /
• 1991

Semi-transparent volume rendering technique can provide 3-D visualization well by voxel level Processing and alleviate segmentation arf, ifacts compared wish the surface rendering technique. In this Paper, we consider several new schemes which can improve she Perform ance of volume rendering. A directional interpolation method is proposed to reduce the artifact due to the anisotrophic resolution in X-ray CT data. The computation time for rendering is shortened by using the depth information of the 3-D object. And also, we reduce the quantization artifacts in the rendering by introducing the opacity-dependent sampling interval to sampling in ray-tracing.

• Korean Journal of Computational Design and Engineering
• /
• v.13 no.6
• /
• pp.469-477
• /
• 2008

Physically-based rendering is an image synthesis technique based on simulation of physical interactions between light and surface materials. Since generated images are highly photorealistic, physically-based rendering has become an indispensable tool in advanced design visualization for manufacturing and architecture as well as in film VFX and animations. Especially, BRDF (bidirectional reflectance distribution function) is critical in realistic visualization of materials since it models how an incoming light is reflected on the surface in terms of intensity and outgoing angles. In this paper, we introduce techniques to represent BRDF as B-spline volumes and to utilize them in physically-based rendering. We show that B-spline volume BRDF (BVB) representation is suitable for measured BRDFs due to its compact size without quality loss in rendering. Moreover, various CAGD techniques can be applied to B-spline volume BRDFs for further controls such as refinement and blending.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.8 no.1
• /
• pp.55-64
• /
• 2012

The advantage of direct volume rendering is to visualize structures of interest in the volumetric data. However it is still difficult to simultaneously show interior and exterior structures. Recently, cone beam computed tomography(CBCT) has been used for dental diagnosis. Despite of its usefulness, there is a limitation in the detection of interior structures such as pulp and inferior alveolar nerve canal. In this paper, we propose an efficient volume rendering model for visualizing important interior as well as exterior structures of dental CBCT. It is based on the concept of illustrative volume rendering and enhances boundary and silhouette of structures. Moreover, we present a new method that assigns a different color to structures in the rear so as to distinguish the front ones from the rear ones. This proposed rendering model has been implemented on graphics hardware, so that we can achieve interactive performance. In addition, we can render teeth, pulp and canal without cumbersome segmentation step.

• Journal of Advanced Navigation Technology
• /
• v.15 no.4
• /
• pp.616-625
• /
• 2011

There are two representative geometry rendering methods. One is Geometry Clipmaps, another is ROAM 2.0. We propose an extended Geometry Clipmaps algorithm which does not focus on CPU operation but the GPU for faster and wider visibility area. The extended algorithm presents mesh configuration method of each level by LOD, how to configurate Mesh network between levels, mesh block method for rendering optimization using VFC, and image mapping method to get high resolution up to 1 m.

• Korean Journal of Computational Design and Engineering
• /
• v.19 no.3
• /
• pp.294-304
• /
• 2014

This paper presents a real-time rendering algorithm of large-scale geometric data using GLSL (OpenGL shading language). It details the VAO (vertex array object) and VBO(vertex buffer object) to be used for up-loading the large-scale point clouds and polygon meshes to a graphic video memory, and describes the shader program composed by a vertex shader and a fragment shader, which manipulates those large-scale data to be rendered by GPU. In addition, we explain the global rendering procedure that creates and runs the shader program with the VAO and VBO. Finally, a rendering performance will be measured with application examples, from which it will be demonstrated that the proposed algorithm enables a real-time rendering of large amount of geometric data, almost impossible to carry out by previous techniques.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.04a
• /
• pp.191-194
• /
• 2012

Rendering maps is an essential feature of the user interface component of a location based service (LBS) system. However, a developer may not too much worry about implementing the rendering maps part of his or her system because there are quite a few publicly available libraries that provide all kinds of functions of manipulating maps. Google Maps, Yahoo Map, Naver Map, Daum Map, and so on are example sites that provide those libraries. Rendering drawings is to indoor LBS as rendering maps is to LBS. However, there is no such thing as Google Maps that provides libraries for rendering drawings. This paper introduces a few web services and a library that is useful in developing user interfaces of indoor LBS systems.

• The Journal of the Korea Contents Association
• /
• v.10 no.8
• /
• pp.119-129
• /
• 2010

Recently, development of mobile service and increased demand for mobile device make mobile environment noticeable in computer graphics. Especially demand for 3D graphic services in mobile devices is steadily increased. However up to the present non-photorealistic rendering is mainly studied in desktop platform. In the result, existing research were designed for desktop computers and are not well-suited for mobile devices. Thus, there is a growing needs for processing techniques that provide the ability to render 3D non-photorealistic graphics through mobile devices. In this paper, we discuss processing techniques for non-photorealistic rendering that are especially cartoon shading and rendering in mobile devices. Through the result of this research, it is expected that silhouette edge rendering for mobile display environment and preprocessing file technique for shading. The efficiency of 3D mobile graphic service like 3D model in cartoon style is increased by using proposed preprocessing file and rendering pipeline. Our work can provide mobile cartoon rendering results and various mobile contents to users.

• The Journal of the Korea Contents Association
• /
• v.6 no.8
• /
• pp.175-183
• /
• 2006

In computer graphics, according as the rapid development of hardware can realize high-resolution image on the monitor, the more natural and accurate rendering skill is needed gradually, and the studies about high-level rendering algorithm are processing. There are two types in rendering skill. The one is photo-realistic rendering to realize accurate image like photos and the other is real-time rendering to realize rapid real-time render. This paper includes caustics expression about lights and materials of several photo-realistic rendering skills. First this paper analyzes how caustics is used and expressed in movies, and further realizes caustics effect using real renderer. This paper examines objective criterion and capability of plug-in through the objective experiment of renderer. Also this paper analyzes using environment on variables for caustics effect realization. The experimental results can be applied to many rendering works as useful data, and can be used as data to understand characteristic and capability.

• Journal of IKEEE
• /
• v.23 no.4
• /
• pp.1366-1372
• /
• 2019

In this paper, we designed a revised neural network to remove the Monte Carlo Rendering noise contained in the ray tracing graphics. The Monte Carlo Rendering is the best way to enhance the graphic's realism, but because of the need to calculate more than thousands of light effects per pixel, rendering processing time has increased rapidly, causing a major problem with real-time processing. To improve this problem, the number of light used in pixels is reduced, where rendering noise occurs and various studies have been conducted to eliminate this noise. In this paper, a deep learning is used to remove rendering noise, especially by separating the rendering image into diffuse and specular light, so that the structure of the dual neural network is designed. As a result, the dual neural network improved by an average of 0.58 db for 64 test images based on PSNR, and 99.22% less light compared to reference image, enabling real-time race-tracing rendering.

• Journal of Korea Game Society
• /
• v.7 no.1
• /
• pp.43-52
• /
• 2007

This article describes a new contribution culling method for fast rendering of complex huge urban scenes. A view frustum culling technique is used for fast rendering of complex scenes. To support the levels-of-detail, we subdivide the image regions and construct a weighted quadtree. Only visible objects at the current camera position contributes the current quadtree and the weight is assigned to each object in the quadtree. The weight is proportional to the image area of the projected object, so large buildings in the far distance are less likely to be culled out than small buildings in the near distance. The rendering time is nearly constant not depending on the number of visible objects. The proposed method has applied to a new metropolitan region which is currently under development. Experimental results showed that the rendering quality of the proposed method is barely distinguishable from the rendering quality of the original method, while the proposed method reduces the number of polygons by about 9%. Experimental results showed that the proposed rendering method is appropriate for real-time rendering applications of complex huge scenes.