• International Journal of Advanced Culture Technology
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• 제8권3호
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• pp.284-290
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• 2020

In this paper, we propose a method to generate and optimize the height map that is suitable to render a soap bubble. The height map represents the flow speed of soap bubbles. To this end, we have analyzed the flow of the soap bubble surface through experiment, derived the moving speed value for each section. Some image filters have been used for optimization that reflects the parameters of the derived height map. In addition, in order to verify the results of the study, actual data measuring the surface flow speed of soap bubbles, the speed of the initial height map, and the optimized height map speed have been compared and tested. Through this study, we reach the issue that it is possible to express the variable flow speed of soap bubbles with the optimized height map, and it will help to express various fluids.

• Journal of Korean Society of Rural Planning
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• 제19권4호
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• pp.177-189
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• 2013

3D modeling and rendering technologies are getting more attention from landscape planners and architects because the virtual reality based on 3D graphic technology could give more realistic experience to landscape simulation users and boost promotional effects. The 3D landscape simulation, however, not only requires a lot of cost and time in production, but also demands efforts to distribute to consumers due to various computing environment of them. The purpose of this study is to suggest a process for developing an interactive 3D landscape simulator with low-cost, which can support multi-platform functionality in high quality through reviewing related current software and web services. We select GIMP for 2D image texturing, SketchUpfor 3D modeling, Unity for real-time rendering, and Google Earth for terrain modeling considering price and workability and apply the developed process for Windows, Web, and Android versions to test the applicability for Sangji-ri, Gosam-myeon, Gyeonggi-do, Korea.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.651-654
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• 2005

Shadows are important elements for realistic rendering of the 3D scene. Image based methods which are techniques to generate shadows are widely used because of fast calculation time. However, this algorithm has aliasing problems. PCF is a method to solve the aliasing problem. Using PCF technique, antialiased shadow boundary can be generated. However, PCF with large filter size requires more time to calculate antialiased shadow boundary. This paper introduces an improved PCF technique which generates antialiased shadow boundary similar to that of PCF. Compared with PCF, this technique can generate antialiased shadows in less time.

• Cartoon and Animation Studies
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• 통권33호
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• pp.425-447
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• 2013

Due to the popularity of digital cameras, there are lots of studies based on ISP(Image Signal Process) and the image correction applications which can easily use for users are being developed. Specially AWB(Automatic White Balance) and Auto exposure are the most interesting fields in ISP function, and they are well used to increase the quality of image. Principles of camera and lighting in 3D program are made based on real camera and lighting. But the functions of automatic exposure and AWB Which are operated in real camera don't work in 3D program. The color correction of images need expertise, it is true that the functions of compositing program are more difficult than the general correction way of digital image. Specially in case of students who studies animation at the university, they make the animation with compositing and rendering without color correction. Thus this research proposed 3D image making process which make to increase the quality of animation, even though the layman can easily correct the color using functions of digital image correction.

• The Journal of the Korea Contents Association
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• 제11권6호
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• pp.106-115
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• 2011

In this paper, we evaluate the effectiveness of previous shading algorithms in depicting shape of 3d objects. We perform a study in which people are shown an image of one of ten 3D objects shaded with one of eight styles and asked to orient a gauge to coincide with the surface normal at many positions on the object's surface. The normal estimates are compared with each other and with ground truth data provided by a registered 3D surface model to analyze accuracy and precision. Our experiments suggest that people interpret certain shape differently depending on shading of 3d object. This paper offers substantial evidence that current computer graphics shading algorithms can effectively depict shape of 3d objects where the algorithms have the properties of lots of tone steps and uniformly distributed tone steps. This type of analysis can guide the future development of new CG shading algorithms in computer graphics for the purpose of shape perception.

• Journal of KIISE:Computer Systems and Theory
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• 제27권7호
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• pp.619-628
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• 2000

Abstract Perspective views provide a powerful depth cue and thus aid the interpretation of complicated images. The main drawback of current perspective volume rendering is the long execution time. In this paper, we present an efficient perspective volume rendering algorithm based on coherency between rays. Two sets of templates are built for the rays cast from horizontal and vertical scanlines in the intermediate image which is parallel to one of volume faces. Each sample along a ray is calculated by interpolating neighboring voxels with the pre-computed weights in the templates. We also solve the problem of uneven sampling rate due to perspective ray divergence by building more templates for the regions far away from a viewpoint. Since our algorithm operates in object-order, it can avoid redundant access to each voxel and exploit spatial data coherency by using run-length encoded volume. Experimental results show that the use of templates and the object-order processing with run-length encoded volume provide speedups, compared to the other approaches. Additionally, the image quality of our algorithm improves by solving uneven sampling rate due to perspective ray di vergence.

• Journal of the Institute of Convergence Signal Processing
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• 제4권3호
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• pp.27-33
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• 2003

The image-based 3D modeling is the technique of generating a 3D graphic model from images acquired using cameras. It is being researched as an alternative technique for the expensive 3D scanner. In this paper, we propose the image-based, 3D modeling system using calibrated stereo cameras. The proposed algorithm for rendering, 3D model consists of three steps, camera calibration, 3D reconstruction, and 3D registration step. In the camera calibration step, we estimate the camera matrix for the image aquisition camera. In the 3D reconstruction step, we calculate 3D coordinates using triangulation from corresponding points of the stereo image. In the 3D registration step, we estimate the transformation matrix that transforms individually reconstructed 3D coordinates to the reference coordinate to render the single 3D model. As shown the result, we generated relatively accurate 3D model.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.1188-1193
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• 2006

본 논문에서는 동적 객체의 3 차원 정보를 표현하는 깊이 영상의 노이즈 필터링 방법을 제안한다. 실제 객체의 동적인 3 차원 정보는 적외선 깊이 센서가 장착된 깊이 비디오 카메라를 이용하여 실시간으로 획득되며, 일련의 깊이 영상, 즉 깊이 비디오(depth video)로 표현될 수 있다. 하지만 측정환경의 조명조건, 객체의 반사속성, 카메라의 시스템 오차 등으로 인해 깊이 영상에는 고주파 성분의 노이즈가 발생하게 된다. 이를 효과적으로 제거하기 위해 깊이 영상기반의 모델링 기법(depth image-based modeling)을 이용한 3 차원 메쉬 모델링을 수행한다. 생성된 3 차원 메쉬 모델은 깊이 영상의 노이즈로 인해 경계 영역과 형상 내부 영역에 심각한 형상 오차를 가진다. 경계 영역의 오차를 제거하기 위해 깊이 영상으로부터 경계 영역을 추출하고, 가까운 순서로 정렬한 후 angular deviation 을 이용하여 불필요하게 중복된 점들을 제거한다. 그리고 나서 2 차원 가우시안 스무딩 기법을 적용하여 부드러운 경계영역을 생성한다. 형상 내부에 대해서는 경계영역에 제약조건을 주고 3 차원 가우시안 스무딩 기법을 적용하여 전체적으로 부드러운 형상을 생성한다. 최종적으로 스무딩된 3 차원 메쉬모델을 렌더링할 때, 깊이 버퍼에 있는 정규화된 깊이 값들을 추출하여 원래 깊이 영상과 동일한 깊이 영역을 가지도록 저장함으로서 전역적으로 연속적이면서 부드러운 깊이 영상을 생성할 수 있다. 제안된 방법에 의해 노이즈가 제거된 깊이 영상을 이용하여 고품질의 영상기반 렌더링이나 깊이 비디오 기반의 햅틱 렌더링에 적용할 수 있다.

• Journal of Korea Game Society
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• 제7권2호
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• pp.21-32
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• 2007

It is significant to simulate scattering of light within media for realistic image synthesis; however, this requires costly computation. This paper introduces a practical image-space approximation technique for interactive subsurface scattering. We use a general two-pass approach, which creates transmitted irradiance samples onto shadow maps and computes illumination using the shadow maps. We estimate single scattering efficiently using a method similar to common shadow mapping with adaptive deterministic sampling. A hierarchical technique is applied to evaluate multiple scattering, based on a diffusion theory. We further accelerate rendering speed by tabulating complex functions and utilizing level of detail. We demonstrate that our technique produces high-quality images of animated scenes with blurred shadow at hundreds frames per second on graphics hardware. It can be integrated into existing interactive systems easily.

• Journal of Korea Society of Industrial Information Systems
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• 제13권1호
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• pp.11-21
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• 2008

Recently, it has shown an increased interest in 3D stereoscopic contents due to the development of the digital image media. Therefore, many techniques in 3D stereoscopic image generation have being researched and developed. However, it is difficult to generate high immersion and natural 3D stereoscopic contents, because the lack of 3D geometric information imposes restrictions in 2D image. In addition, control of the camera interval and rendering of the both eyes must be repetitively accomplished for the stereo effect being high. Therefore, we propose integrated editing system for 3D stereoscopic contents production using a variety of images. Then we generate 3D model from projective geometric information in single 2D image using image-based modeling method. And we offer real-time interactive 3D stereoscopic preview function for determining high immersion 3D stereo view. And then we generate intuitively 3D stereoscopic contents of high-quality through a stereoscopic LCD monitor and a polarizing filter glasses.