• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.815-816
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• 2008

In this paper, we evaluate depth image preprocessing for 3D data service based on DIBR over T-DMB. We evaluate two preprocessing methods of depth images. These are gaussian smoothing and adaptive smoothing. The results show that adaptive smoothing is more suitable for images with sharp transition of depth.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.685-687
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• 2005

본 논문에서는 깊이 영상기반 3차원 물체(depth image-based 3-D object)의 고속 렌더링 기법을 제안한다. 제안하는 알고리즘은 그래픽 가속기가 지원하는 shader programming 기법을 이용하여 하드웨어 가속을 직접 이용하도록 설계되었다. 또한, 기존의 영상 기반 렌더링의 한계를 극복하여 조명 효과를 표현할 수 있으며 렌더링시 각 화소당 Splat 크기를 하드웨어에서 직접 조절하여 고속 렌더링이 가능하다. 모의 실험결과, 소프트웨어 렌더링 또는 OpenGL 기반의 렌더링에 비해 괄목할 만한 렌더링 속도의 향상이 이루어졌다.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.679-691
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• 2002

Volume visualization is an important subarea of scientific visualization, and is concerned with techniques that are effectively used in generating meaningful and visual information from abstract and complex volume datasets, defined in three- or higher-dimensional space. It has been increasingly important in various fields including meteorology, medical science, and computational fluid dynamics, and so on. On the other hand, virtual reality is a research field focusing on various techniques that aid gaining experiences in virtual worlds with visual, auditory and tactile senses. In this paper, we have developed a visualization system for CAVE, an immersive 3D virtual environment system, which generates stereoscopic images from huge human volume datasets in real-time using an improved volume visualization technique. In order to complement the 3D texture-mapping based volume rendering methods, that easily slow down as data sizes increase, our system utilizes an image-based rendering technique to guarantee real-time performance. The system has been designed to offer a variety of user interface functionality for effective visualization. In this article, we present detailed description on our real-time stereoscopic visualization system, and show how the Visible Korean Human dataset is effectively visualized on CAVE.

• Cartoon and Animation Studies
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• s.40
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• pp.157-176
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• 2015

This research describes render pass synthetic techniques required to use for the effectiveness of them in 3D animation synthetic technology. As the render pass is divided by property and synthesized after rendering, elaborate, rapid synthesis can be achieved. In particular, occlusion pass creates a screen as if it had a soft, light shading, expressing a sense of depth and boundary softness. It is converted into 2D image through a process of pass rendering of animation projects created in 3D space, then completed in synthetic software. Namely, 3D animation realizes the completeness of work originally planned through compositing, a synthetic process in the last half. To complete in-depth image, a scene manufactured in 3D software can be sent as a synthetic program by rendering the scene by layer and property. As recently the occlusion pass can express depth notwithstanding conducting GI rendering of 3D graphic outputs, it is an important synthetic map not omitted in the post-production process. Nonetheless, for the importance of it, currently the occlusion pass leaves much to be desired for research support and books summarizing and analyzing the characteristics of properties, and the principles and usages of them. Hence, this research was aimed to summarize the principles and usages of occlusion map, and analyze differences in the results of synthesis. Furthermore, it also summarized a process designating renderers and the map utilizing the properties, and synthetic software usages. For the future, it is hoped that effective and diverse latter expression techniques will be studied beyond the limitation of graphic expression based on trends diversifying technique development.

• Proceedings of the KSRS Conference
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• v.1
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• pp.417-420
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• 2006

In these days, mobile application dealing with information contents on mobile or handheld devices such as mobile communicator, PDA or WAP device face the most important industrial needs. The motivation of this study is the design and implementation of mobile application using high resolution satellite imagery, large-sized image data set. Although major advantages of mobile devices are portability and mobility to users, limited system resources such as small-sized memory, slow CPU, low power and small screen size are the main obstacles to developers who should handle a large volume of geo-based 3D model. Related to this, the previous works have been concentrated on GIS-based location awareness services on mobile; however, the mobile 3D terrain model, which aims at this study, with the source data of DEM (Digital Elevation Model) and high resolution satellite imagery is not considered yet, in the other mobile systems. The main functions of 3D graphic processing or pixel pipeline in this prototype are implemented with OpenGL|ES (Embedded System) standard API (Application Programming Interface) released by Khronos group. In the developing stage, experiments to investigate optimal operation environment and good performance are carried out: TIN-based vertex generation with regular elevation data, image tiling, and image-vertex texturing, text processing of Unicode type and ASCII type.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.1
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• pp.13-22
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• 2000

We present a method that enhances the rendering speed of z-buffer algorithm using temporal coherence between two contiguous frames on fixed viewing conditions. Conventional z-buffer algorithm stores depth value for each pixel on a view plane while rendering some polygons, then it determines the visibility of the remaining polygons based on the stored depth values. If we can get color and depth information for some polygons without rendering, it is possible to generate an image by rendering only the remaining ones. In case of high frame rate, we can find the fact that sets of static polygons of the two contiguous frames are almost the same. This temporal coherence enables us to get the color and depth information of static polygons efficiently. Our algorithm stores color and depth information of static polygons and reuses it for generating the next frame. This method can be easily implemented since it does not require complex data structure and modification for conventional z-buffer algorithm. Also it is adequate for hardware implementation.

• Journal of Korea Multimedia Society
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• v.15 no.6
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• pp.711-721
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• 2012

The objective of this study is to propose an efficient 3D reconstruction method for developing a stereo-vision-based haptics system which can replace "robotic eyes" and "robotic touch." The haptic rendering for 3D images requires to capture depth information and edge information of stereo images. This paper proposes the 3D reconstruction methods using LoG(Laplacian of Gaussian) algorithm and DoG(Difference of Gaussian) algorithm for edge detection in addition to the basic 3D depth extraction method for better haptic rendering. Also, some experiments are performed for evaluating the CPU time and the error rates of those methods. The experimental results lead us to conclude that the DoG method is more efficient for haptic rendering. This paper may contribute to investigate the effective methods for 3D image reconstruction such as in improving the performance of mobile patrol robots.

• Journal of Korea Multimedia Society
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• v.18 no.8
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• pp.960-967
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• 2015

In this paper, we propose a user interface technique based on embedded sensors applying to apps in smart phone. Especially, we implement avata generation application using image filtering technique for photo image in smart phone. In the application, The embedded sensors are used as intuitive user interface to adjust the image filtering effect for making user satisfied effect in real time after the system produced the image filtering effect for avatar. This technique provides not a simple typed method of parameter values adjustment but a new intuitively emotional adjustment method in image filtering applications. The proposed technique can use sound values from embedded mike sensor for adjusting key values of sketch filter effect if the smart phone user produces sound. Similiarly the proposed technique can use coordinate values from embedded acceleration sensor for adjusting masking values of oil painting filter effect and use brightness values from embedded light sensor for adjusting masking values of sharp filter effect. Finally, we implement image filtering application and evaluate efficiency and effectiveness for the proposed technique.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.181.5-181
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• 2001

This paper presents the method of 3D reconstruction of the depth information from the endoscopic stereo scopic images. After camera modeling to find camera parameters, we performed feature-point based stereo matching to find depth information. Acquired some depth information is finally 3D reconstructed using the NURBS(Non Uniform Rational B-Spline) algorithm. The final result image is helpful for the understanding of depth information visually.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.167-170
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• 2000

인터넷 기술의 발전과 더불어 가상현실을 표현하기 위한 컴퓨터 그래픽스 파일 포맷(format) 기술(specification) 표준화가 진행중이다. 가상현실에서 시각효과의 영향이 가장 크기 때문에, 실시간에 가장 사실적인 영상을 제공하는 여러 가지 기술들이 개발되어 왔다. 본 논문에서는 현실감을 높이면서 빠른 시간에 렌더링 영상을 제공하는 방법들 중 하나인 영상기반 렌더링 방법에 대한 노드를 설계하여 VRML 확장 노드로 제안하고자 한다.