• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2005년도 추계학술대회 논문집
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• pp.1-5
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• 2005

The digital HPTV velocity field measurement consists of four steps: recording, numerical reconstruction, particle extraction and velocity extraction. In the velocity extraction process, we improved PTV algorithm to extract the displacement of particle each placed in 3D space. Because a digital recording device was used, some factors such as a spatial resolution, numerical aperture, and particle concentration can affect the performance of the digital HPTV. Especially, a particle concentration ($C_{o}$) affected tile reconstruction efficiency in numerical reconstruction and particle extraction process. In this paper, the reconstruction efficiency was analyzed experimentally with different particle concentration. Optimal reconstruction efficiency was shown in the range of $C_{o}$=$13\∼15$ particles/$mm^{3}$.

• 대한기계학회논문집B
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• 제30권10호
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• pp.929-934
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• 2006

The digital HPTV(holographic particle tracking velocimetry) velocity field measurement system consists of four steps: recording, numerical reconstruction, particle extraction and velocity extraction. In the velocity extraction process, we improved the two frame PTV algorithm to extract 3-D displacement information of each particle located in 3D space. Because a digital CCD camera was used, some factors such as spatial resolution, numerical aperture, and particle concentration influenced on the performance of the developed digital HPTV. Especially, the particle concentration $(C_o)$ affected the reconstruction efficiency and recovery ratio in the numerical reconstruction and particle extraction procedure. In this paper, the effect of particle concentration reconstruction efficiency and recovery ratio were analyzed experimentally. Optimal particle concentration was found to be in the range of $C_o=11{\sim}17\;particles/mm^3$.

• ETRI Journal
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• 제27권2호
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• pp.235-238
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• 2005

A new mesh reconstruction scheme for approximating a surface from a set of unorganized 3D points is proposed. The proposed method, called a shrink-wrapped boundary face (SWBF) algorithm, produces the final surface by iteratively shrinking the initial mesh generated from the definition of the boundary faces. SWBF surmounts the genus-0 spherical topology restriction of previous shrink-wrapping-based mesh generation techniques and can be applied to any type of surface topology. Furthermore, SWBF is significantly faster than a related algorithm of Jeong and others, as SWBF requires only a local nearest-point-search in the shrinking process. Our experiments show that SWBF is very robust and efficient for surface reconstruction from an unorganized point cloud.

• 한국광학회지
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• 제17권4호
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• pp.335-341
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• 2006

마이켈슨 간섭계 시스템에 두 개의 Convex Lens를 추가함으로서 평면파 참조광을 유지 시키며, 물체에 조사되는 물체광의 조사면적을 증대시킬 수 있는 변형된 마이켈슨 간섭계를 제작하였다. 변형된 마이켈슨 간섭계를 반사형 디지털 홀로그래피 현미경 시스템(Digital Holography Microscope System)에 적용한 결과 두 개의 Convex Lens를 추가하지 않은 고전 마이켈슨 간섭계를 사용한 디지털 홀로그래피 현미경 시스템 보다 넓은 영역에 대해 물체를 기록 할 수 있으며 또한 보다 넓은 영역을 재생 할 수가 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.3121-3142
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• 2017

We present a method for 3D shape reconstruction of inextensible deformable surfaces from a single image. The key of our approach is to represent the surface as a 3D triangulated mesh and formulate the reconstruction problem as a sequence of Linear Programming (LP) problems. The LP problem consists of data constraints which are 3D-to-2D keypoint correspondences and shape constraints which are designed to retain original lengths of mesh edges. We use a closed-form method to generate an initial structure, then refine this structure by solving the LP problem iteratively. Compared with previous methods, ours neither involves smoothness constraints nor temporal consistency, which enables us to recover shapes of surfaces with various deformations from a single image. The robustness and accuracy of our approach are evaluated quantitatively on synthetic data and qualitatively on real data.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.83-86
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• 2005

This paper presents a method for point-based 3D building reconstruction using LiDAR data and digital map. The proposed method consists of three processes: extraction of building roof points, identification of roof types, and 3D building reconstruction. After extracting points inside the polygon of building, the ground surface, wall and tree points among the extracted points are removed through the filtering process. The filtered points are then fitted into the flat plane using ODR(Orthogonal Distance Regression). If the fitting error is within the predefined threshold, the surface is classified as a flat roof. Otherwise, the surface is fitted and classified into a gable or arch roof through RMSE analysis. Based on the roof types identified in automated fashion, the 3D building reconstruction is performed. Experimental results showed that the proposed method classified successfully three different types of roof and that the fusion of LiDAR data and digital map could be a feasible method of modelling 3D building reconstruction.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.1257-1264
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• 2009

문화유산 디지털 복원에 기반한 영상콘텐츠의 경우 현재 박물관, 미술관, 특별전시 등을 중심으로 활발하게 제작되고 있다. 그러나 아직까지 프로덕션에 관한 구체적인 가이드라인이 존재하지 않으며 파이프라인 역시 체계적이지 못해 프로덕션 과정에서 비효율적인 시간과 비용이 발생하는 것이 사실이다. 디지털 복원 기반의 영상콘텐츠는 영화, 혹은 다큐멘터리 프로덕션과도 흡사해 보이지만 용도의 특수성을 감안해 프로덕션의 독자적인 파이프라인을 수립하는 것이 중요하다. 카이스트 문화기술센터 디지털 해리티지 그룹은 국립중앙박물관과 함께 이란의 유적지인 페르세폴리스, 경주의 석굴암, 국립 문화재청과 함께 베트남의 고도 후에를 디지털 복원하고 이를 시각적으로 구현한 영상콘텐츠를 제작하였다. 디지털 헤리티지 그룹의 사례연구를 통해 효과적인 프로덕션을 목표로 가정한 파이프라인 모델을 소개한다.

• Journal of Information Processing Systems
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• 제14권6호
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• pp.1445-1456
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• 2018

Environment perception and three-dimensional (3D) reconstruction tasks are used to provide unmanned ground vehicle (UGV) with driving awareness interfaces. The speed of obstacle segmentation and surrounding terrain reconstruction crucially influences decision making in UGVs. To increase the processing speed of environment information analysis, we develop a CPU-GPU hybrid system of automatic environment perception and 3D terrain reconstruction based on the integration of multiple sensors. The system consists of three functional modules, namely, multi-sensor data collection and pre-processing, environment perception, and 3D reconstruction. To integrate individual datasets collected from different sensors, the pre-processing function registers the sensed LiDAR (light detection and ranging) point clouds, video sequences, and motion information into a global terrain model after filtering redundant and noise data according to the redundancy removal principle. In the environment perception module, the registered discrete points are clustered into ground surface and individual objects by using a ground segmentation method and a connected component labeling algorithm. The estimated ground surface and non-ground objects indicate the terrain to be traversed and obstacles in the environment, thus creating driving awareness. The 3D reconstruction module calibrates the projection matrix between the mounted LiDAR and cameras to map the local point clouds onto the captured video images. Texture meshes and color particle models are used to reconstruct the ground surface and objects of the 3D terrain model, respectively. To accelerate the proposed system, we apply the GPU parallel computation method to implement the applied computer graphics and image processing algorithms in parallel.

• International Journal of Advanced Culture Technology
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• 제12권1호
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• pp.123-127
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• 2024

In the early 20th century, Walter Benjamin analyzed the changes in the value of traditional art forms under the industrial era and the changes in the aesthetic attitude of the masses. A century later, in the contemporary multi-art world, the traditional medium of shelf painting is once again experiencing a similar situation as the last century. Emerging technology display modes such as digital virtual reality and digital immersive experience can achieve digital reproduction of paintings on shelves and reach a certain level of performance, which once again shocks the public's aesthetic perception. This paper attempts to illustrate the outstanding characteristics of the new art form after digital reconstruction by exploring the transformation and sublimation of digital technology to shelf painting. We predict that art research on future reality and augmented reality according to the artificial intelligence era will be conducted in depth in the future.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.177-178
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• 2006

Digital holographic particle tracking velocimetry (HPTV) is developed by single high-speed camera and single continuous laser with long coherent length. This system can directly capture 4000 hologram fringe images for 1 second through a camera computer memory. The 3D particle location is made of the reconstruction by using a computer hologram algorithm. This system can successfully be applied to instantaneous 3D velocity measurement in the water flow inside a micro-tube. The average of 100 instantaneous velocity vectors is obtained by reconstruction and tracking with the time of evolution of recorded fringes images. In the near future, we will apply this technique to measure 3D flow information inside various micro structures.