• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.670-673
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• 2003

Fabrication of three dimensional microstructures by laser-assisted chemical vapor deposition of material is investigated. To fabricate microstructures, a thin layer of deposit in desired patterns is first written using laser direct writing technique and on top of this layer a second layer is deposited to provide the third dimension normal to the surface. By depositing many layers. a three dimensional microstructure is fabricated. Optimum deposition conditions for direct writing of initial and subsequent layers with good surface quality and profile uniformity are determined. Using an arson ion laser and ethylene as the light source and reaction gas, respectively, fabrication of three-dimensional carbon microstructures is demonstrated.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2605-2608
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• 2003

This paper presents design and implementation methods of the real-time three dimensional tracking system of the gazing point. The proposed method is based on three dimensional data processing of eye images in the 3D world coordinates. The system hardware consists of two conventional CCD cameras for acquisition of stereoscopic image and computer for processing. And in this paper, the advantages of the proposed algorithm and test results ate described.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.188-198
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• 2021

Digital data was collected using modern three-dimensional digital technology. Current content-specific technologies were investigated through domestic and foreign cases so that three-dimensional digital technology could be applied to the utilization of various contents. First, the use of three-dimensional digital technology of architectural cultural assets has been changing from the restoration of cultural assets. Second, some of the contents produced were found to be underutilized. Third, the type of content has been changing in experience and exhibition, but the online approach was small. Fourth, digital restoration using domestic IT technology has been used as a technology to restore overseas cultural heritage. The fifth analysis of the relationship between the content types and 3D digital technologies shows the use of currently limited technologies. This study analyzed the status of digital architecture and the application of three-dimensional digital technologies to lay the foundation for the active development and utilization of content. Subsequent studies on various layers and digital technologies will be needed to revitalize digital architectural cultural assets in the future.

• Journal of Korean Dental Science
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• v.15 no.1
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• pp.19-30
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• 2022

Purpose: The purpose of the study was to assess the validity of three-dimensional (3D) facial scan taken with facial scanner and digital photo wrapping on the cone-beam computed tomography (CBCT). Materials and Methods: Twenty-five patients had their CBCT scan, two-dimensional (2D) standardized frontal photographs and 3D facial scan obtained on the same day. The facial scans were taken with a facial scanner in an upright position. The 2D standardized frontal photographs were taken at a fixed distance from patients using a camera fixed to a cephalometric apparatus. The 2D integrated facial models were created using digital photo wrapping of frontal photographs on the corresponding CBCT images. The 3D integrated facial models were created using the integration process of 3D facial scans on the CBCT images. On the integrated facial models, sixteen soft tissue landmarks were identified, and the vertical, horizontal, oblique and angular distances between soft tissue landmarks were compared among the 2D facial models and 3D facial models, and CBCT images. Result: The results showed no significant differences of linear and angular measurements among CBCT images, 2D and 3D facial models except for Se-Sn vertical linear measurement which showed significant difference for the 3D facial models. The Bland-Altman plots showed that all measurements were within the limit of agreement. For 3D facial model, all Bland-Altman plots showed that systematic bias was less than 2.0 mm and 2.0° except for Se-Sn linear vertical measurement. For 2D facial model, the Bland-Altman plots of 6 out of 11 of the angular measurements showed systematic bias of more than 2.0°. Conclusion: The facial scan taken with facial scanner showed a clinically acceptable performance. The digital 2D photo wrapping has limitations in clinical use compared to 3D facial scans.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.46-49
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• 2005

In this paper, a novel 2D/3D convertible display system based on integral imaging is proposed. Combining two liquid crystal display panels with integral imaging, it is possible to convert the display between two-dimensional mode and three-dimensional mode without mechanical movement. The proposed method is proven by preliminary experiments.

• Korean Journal of Radiology
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• v.22 no.5
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• pp.782-791
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• 2021

Objective: To evaluate the signal intensity of the periosteum using ultrashort echo time pulse sequence with three-dimensional cone trajectory (3D UTE) with or without fat suppression (FS) to distinguish from artifacts in porcine tibias. Materials and Methods: The periosteum and overlying soft tissue of three porcine lower legs were partially peeled away from the tibial cortex. Another porcine tibia was prepared as three segments: with an intact periosteum outer and inner layer, with an intact periosteum inner layer, and without periosteum. Axial T1 weighted sequence (T1 WI) and 3D UTE (FS) were performed. Another porcine tibia without periosteum was prepared and subjected to 3D UTE (FS) and T1 WI twice, with positional changes. Two radiologists analyzed images to reach a consensus. Results: The three periosteal tissues that were partially peeled away from the cortex showed a high signal in 3D UTE (FS) and low signal on T1 WI. 3D UTE (FS) showed a high signal around the cortical surface with an intact outer and inner periosteum, and subtle high signals, mainly around the upper cortical surfaces with the inner layer of the periosteum and without periosteum. T1 WI showed no signal around the cortical surfaces, regardless of the periosteum state. The porcine tibia without periosteum showed changes in the high signal area around the cortical surface as the position changed in 3D UTE (FS). No signal was detected around the cortical surface in T1 WI, regardless of the position change. Conclusion: The periosteum showed a high signal in 3D UTE and 3D UTE FS that overlapped with artifacts around the cortical bone.

• Journal of Information Display
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• v.13 no.2
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• pp.55-59
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• 2012

In this paper, a concept of an integrated elastomer substrate for a three-dimensional (3D) liquid crystal display based on the integral-imaging method is presented. The elemental lens array and columnar spacers were integrated into one of the two substrates, an elastomer substrate, through an imprinting process. The integrated elastomer substrate was capable of maintaining the uniform liquid crystal (LC) cell gap and promoting homeotropic LC alignment without any surface treatment. The monolithic approach reported herein will provide a key component for 3D displays with enhanced portability through a more than 40% weight reduction compared with the conventional integral-imaging method.

• The korean journal of orthodontics
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• v.47 no.6
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• pp.394-400
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• 2017

Assessing the condition of the alveolar bone before and after orthodontic treatment is important. Recently, cone-beam computed tomography has been widely accepted as a useful tool for orthodontic treatment. Moreover, using a three-dimensional (3D) structural analysis software enables gathering detailed information and quantifying data. The aim of this study was to introduce various quantitative analyses performed before and after orthodontic treatment by using a 3D structural analysis software for evaluating the morphological condition of the alveolar bone of a patient with gingival recession around the canines.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.714-717
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• 2008

In this paper, we propose a three-dimensional (3D) integral imaging system using an elastic lens array instead of conventional rigid lens array. The lens array is made of polydimethylsiloxane (PDMS) that is optically transparent and flexible material. We can stretch the PDMS lens array to be expanded into a certain extent, and control the lens pitch of the system easily. That flexible design enables a fine 3D integral imaging display.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.11
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• pp.827-833
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• 2009

The present study numerically investigates three-dimensional laminar flow past a rotating circular cylinder placed in a uniform stream. For the purpose of a careful analysis of the modification of flow by the effect of the rotation on the flow, numerical simulations are performed at a various range of rotational coefficients ($0{\leq}{\alpha}{\leq}2.5$) at one Reynolds number of 300. As ${\alpha}$ increases, flow becomes stabilized and finally a steady state beyond the critical rotational coefficient. The 3D (three dimensional) wake mode of the stationary cylinder defined at this Reynolds number has been disorganized according to ${\alpha}$, which were observed by the visualization of 3D vortical structures. The variation of the Strouhal number is very weak when the wake pattern is changed according to the rotational coefficient. As ${\alpha}$ increases, the lift increases, whereas the drag decreases.