• International Journal of Air-Conditioning and Refrigeration
• /
• 제8권2호
• /
• pp.11-22
• /
• 2000

Holographic interferometric tomography can provide reconstruction of instantaneous three-dimensional gross flow fields. The technique however confronts ill-posed reconstruction problems in practical applications. Experimental data are usually limited in projection and angular scanning when a field is captured instantaneously or under the obstruction of test models and test section enclosures. An algorithm, based on a series expansion method, has been developed to improve the reconstruction under the ill-posed conditions. A three-dimensional natural convection flow around two interacting isothermal cubes is experimentally investigated. The flow can provide a challenging reconstruction problem and lend itself to accurate numerical solution for comparison. The refractive index fields at two horizontal sections of the thermal plume with and without an opaque object are reconstructed at a limited view angle of 80$\circ$. The experimental reconstructions are then compared with those from numerical calculation and thermocouple thermometry. It confirms that the technique is applicable to reconstruction of reasonably complex, three-dimensional flow fields.

• Journal of International Society for Simulation Surgery
• /
• 제1권1호
• /
• pp.19-22
• /
• 2014

As computer technology develops and this is applied to medical image field, three dimensional image reconstruction technology using computer simulation is utilized in various categories that include anatomical study and biomechanics study of human body. Especially orthopedic surgeons are able to investigate biomechanical function and be provided information for operations with this technology in terms of ligament reconstruction of knee. And this technology can be utilized in preparing preoperative planning and instructions and training. This review is about three dimensional image reconstruction technology which is utilized in ligament reconstruction of knee.

• 비파괴검사학회지
• /
• 제25권6호
• /
• pp.431-438
• /
• 2005

Bubble behaviors in a circular tube have been analyzed numerically and experimentally by a three-dimensional tomography method, Initially, a multiplicative algebraic reconstruction technique (MART) which showed better results for previous studies of numerical simulations has been performed to confirm the accuracy of the three-dimensional reconstruction for the two-phase flow using a computer-synthesized phantom, Then, bubble behaviors have been investigated experimentally by the three-dimensional MART method using real projected data captured simultaneously by a laser and three CCD cameras for three angles of view, Also, the transient reconstructions have been attempted to analyze the real-time oxygen-bubble movements in water by the interval of 1/30 second.

• 설비공학논문집
• /
• 제11권6호
• /
• pp.749-757
• /
• 1999

Holographic interferornetric tomography can provide reconstruction of instantaneous three dimensional gross flow fields. The technique however confronts ill-posed reconstruction problems in practical applications. Experimental data are usually limited in projection and angular scanning when a field is captured instantaneously or under the obstruction of test models and test section enclosures. An algorithm, based on a series expansion method, has been developed to improve the reconstruction under the ill-posed conditions. A three-dimensional natural convection flow around two interacting isothermal cubes is experimentally investigated. The flow can provide a challenging reconstruction problem and lend itself to accurate numerical solution for comparison. The refractive index fields at two horizontal sections of the thermal plume with and without an opaque object are reconstructed at a limited view angle of 80" The experimental reconstructions are then compared with those from numerical calculation and thermocouple thermometry. It confirms that the technique is applicable to reconstruction of reasonably complex, three-dimensional flow fields.elds.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.37-42
• /
• 2005

This paper presents an autonomous system for reconstruction of three-dimensional indoor environments using a mobile robot. The system is composed of a mobile robot, a three-dimensional scanning system, and a notebook computer for registration, observation planning and real-time three-dimensional data transferring. Three-dimensional scanning system obtains three-dimensional environmental data and performs filtering of dynamic objects. Then, it registers multiple three-dimensional scans into one coordinate system and performs observation planning which finds the next scanning position by using the layered hexahedral-map and topological-map. Then, the mobile robot moves to the next scanning position, and repeats all procedures until there is no scanning tree in topological-map. In concurrence with data scanning, three-dimensional data can be transferred through wireless-LAN in real-time. This system is experimented successfully by using a mobile robot named KARA.

• Applied Microscopy
• /
• 제39권4호
• /
• pp.349-354
• /
• 2009

TFT-LCD의 구조불량이 발생한 박막 트랜지스터에 대해서 집속이온빔 가공장치(Dual-beam FIB/SEM)를 이용하여 연속절편법(Serial sectioning)과 일련의 연속적인 2차원 주사전자현미경 이미지를 얻었고, IMOD 소프트웨어를 통해서 3차원 구조구현(3D reconstruction) 연구를 하였다. 3차원 구조구현 결과, Gate막과 Data막이 접합되어 있는 불량이 관찰되었다. 두 막이 접합되어서 ON/OFF 역할을 하는 Gate의 기능이 상실되었고, Data신호는 Drain을 통해서 투명전극에 전류를 공급하여 계속 빛나는 선 불량(line defect)이 발생한 것으로 판단된다. 이 논문의 결과인 집속이온빔 가공장치(Dual-Beam FIB/SEM)를 이용한 3차원 구조구현 연구와 연속절편법, 주사전자현미경 이미지작업, 이미지 프로세싱에 대한 결과는 향후 연구의 기초자료로 활용될 수 있을 것으로 판단된다.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2009년 추계학술대회논문집
• /
• pp.193-200
• /
• 2009

Recently, there have been efforts to construct hybrids among the existing methodologies for multiphase flow such as VOF, Level Set, and Front Tracking with the intention of facilitating simulations of general three-dimensional problems. As one of the hybrid method, we have developed the Level Contour Reconstruction Method (LCRM) for general three-dimensional multiphase flows including phase change. The main idea was focused on simplicity and a robust algorithm especially for the three-dimensional case. It combines characteristics of both Front Tracking and Level Set methods. While retaining an explicitly tracked interface using interfacial elements, the calculation of a vector distance function plays a crucial role in the periodic reconstruction of the interface elements in the LCRM method to maintain excellent mass conservation and interface fidelity. In addition, compact curvature formulation is incorporated for the calculation of the surface tension force thereby reducing parasitic currents to a negligible level.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제47권3호
• /
• pp.233-236
• /
• 2021

A mandibular continuity defect can be repaired using either a prosthetic device or autogenous bone. A titanium reconstruction plate can be used with a localized or vascularized flap over the defect of the mandible. Unfortunately, the plate may fail due to plate exposure, screw loosening, fracture, or infection, and will need to be removed. Plate exposure though the skin or mucosa is one of the main reasons for failure. In the present work, the authors introduced a lingually positioned reconstruction plate fabricated via three-dimensional printed bending support. This custom reconstruction plate can avoid plate re-exposure as well as reduce surgical errors and operation time.

• Journal of International Society for Simulation Surgery
• /
• 제1권2호
• /
• pp.99-102
• /
• 2014

The skull defect can be made after the trauma, oncologic problems or neurosurgery. The skull reconstruction has been the challenging issue in craniofacial fields for a long time. So far the skull reconstruction with autogenous bone would be the standard. Although the autogenous bone would be the ideal one for skull reconstruction, donor site morbidity would be the inevitable problem in many cases. Meanwhile various types of allogenic and alloplastic materials have been also used. However, skull reconstruction with many alloplastic material have produced no less complications including infection, exposure, and delayed wound healing. Because the 3D printing technique evolved so fast that 3D printed titanium implant were possible recently. The aim of this trial is to try to restore the original skull anatomy as possible using the 3D printed titanium implant, based on the mirrored three dimensional CT images based on the computer simulation. Preoperative computed tomography (CT) data were processed for the patient and a rapid prototyping (RP) model was produced. At the same time, the uninjured side was mirrored and superimposed onto the traumatized side, to create a mirror-image of the RP model. And we fabricated Titanium implant to reconstruct three-dimensional orbital structure in advance, using the 3D printer. This prefabricated Titanium-implant was then inserted onto the defected skull and fixed. Three dimensional printing technique of titanium material based on the computer simulation turned out to be very successful in this patient. Individualized approach for each patient could be an ideal way to manage the traumatic patients in near future.

• 제어로봇시스템학회논문지
• /
• 제8권1호
• /
• pp.21-27
• /
• 2002

Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. A number of visual or optical technologies have been successfully applied to measure three-dimensional surfaces. However, those conventional visual or optical methods have inherent shortcomings such as occlusion and variant surface reflection. X-ray vision system can be a good solution to these conventional problems, since we can extract the volume information including both the surface geometry and the inner structure of any objects. In the x-ray system, the surface condition of an object, whether it is lambertian or specular, does not affect the inherent characteristics of its x-ray images. In this paper, we propose a three-dimensional x-ray imaging method to reconstruct a three dimensional structure of an object out of two dimensional x-ray image sets. To achieve this by the proposed method, two or more x-ray images projected from different views are needed. Once these images are acquired, the simultaneous algebraic reconstruction technique(SART) is usually utilized. Since the existing SART algorithms have several shortcomings such as low performance in convergence and different convergence within the reconstruction volume of interest, an advanced SART algorithm named as USART(uniform SART) is proposed to avoid such shortcomings and improve the reconstruction performance. Because, each voxel within the volume is equally weighted to update instantaneous value of its internal density, it can achieve uniform convergence property of the reconstructed volume. The algorithm is simulated on various shapes of objects such as a pyramid, a hemisphere and a BGA model. Based on simulation results the performance of the proposed method is compared with that of the conventional SART method.