• 비파괴검사학회지
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• 제22권5호
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• pp.545-556
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• 2002

Algebraic reconstruction technique (ART)과 multiplicative algebraic reconstruction technique (MART)이라는 토모그래피 방법을 이용하여 2상유동에서 기포의 거동을 배침투적으로 분석하였다. 먼저, 컴퓨터 합성 영상장으로 환상유통과 기포유동을 제작하여 2차원 단면의 재건을 시도하였다. 2상유동의 보다 정확한 결과들을 얻기 위하여 두가지 토모그래피 방법이 비교되었다. 그리고, 2상유동에서 기포의 거동을 3차원으로 분석하기 위하여 2개와 3개의 기포가 존재하는 3차원 합성 영상장으로부터 2차원 단면에서 보다 정확한 결과를 보인 MART 재건법에 의해서 밀도 분포 해석을 수행하였다.

• 대한두개안면성형외과학회지
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• 제19권3호
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• pp.200-204
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• 2018

Fibrous dysplasia (FD) is a rare, benign bone disease with abnormal bone maturation and fibroblastic proliferation. Optimal treatment of zone 1 craniofacial FD is radical resection and reconstruction. To achieve of structural, aesthetic, and functional goals, we use three-dimensionally designed calvarial bone graft for reconstruction of zygomatic defect after radical resection of FD. The authors used a rapid-prototyping model for simulation surgery for radical resection and immediate reconstruction. Donor site was selected from parietal bone reflect shape, contour, and size of defect. Then radical resection of lesion and immediate reconstruction was performed as planned. Outcomes were assessed using clinical photographs and computed tomography scans. Successful reconstruction after radical resection was achieved by three-dimensional calvarial bone graft without complications. After a 12-month follow-up, sufficient bone thickness and symmetric soft tissue contour was well-maintained. By considering three-dimensional configuration of zygomaticomaxillary complex, the authors achieved satisfactory structural, aesthetic and functional outcomes without complications.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1989년도 춘계학술대회
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• pp.55-59
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• 1989

A true three-dimensional cone-beam reconstruction (TTCR) algorithm for the complete sphere geometry is derived, which is applicable to the direct volume image reconstruction from 2-D cone-beam projections. The algorithm is based on the modified filtered backprojection technique which uses a set of 2-D space-invariant filters and is derived from the previously developed parallel-beam true three-dimensional reconstruction(TTR) algorithm. The proposed algorithm proved to be superior in spatial resolution compared with the parallel-beam TTR algorithm.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제23권3호
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• pp.203-210
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• 2019

We present the three-dimensional volume reconstruction model using the modified Cahn-Hilliard equation with a fractional Laplacian. From two-dimensional cross section images such as computed tomography, magnetic resonance imaging slice data, we suggest an algorithm to reconstruct three-dimensional volume surface. By using Laplacian operator with the fractional one, the dynamics is changed to the macroscopic limit of Levy process. We initialize between the two cross section with linear interpolation and then smooth and reconstruct the surface by solving modified Cahn-Hilliard equation. We perform various numerical experiments to compare with the previous research.

• Journal of information and communication convergence engineering
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• 제14권1호
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• pp.51-56
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• 2016

In this paper, we present a three-dimensional (3-D) automatic target recognition system based on optical integral imaging reconstruction. In integral imaging, elemental images of the reference and target 3-D objects are obtained through a lenslet array or a camera array. Then, reconstructed 3-D images at various reconstruction depths can be optically generated on the output plane by back-projecting these elemental images onto a display panel. 3-D automatic target recognition can be implemented using computational integral imaging reconstruction and digital nonlinear correlation filters. However, these methods require non-trivial computation time for reconstruction and recognition. Instead, we implement 3-D automatic target recognition using optical cross-correlation between the reconstructed 3-D reference and target images at the same reconstruction depth. Our method depends on an all-optical structure to realize a real-time 3-D automatic target recognition system. In addition, we use a nonlinear correlation filter to improve recognition performance. To prove our proposed method, we carry out the optical experiments and report recognition results.

• 한국음향학회지
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• 제28권8호
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• pp.723-731
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• 2009

본 논문에서는 3차원 라우드스피커 어레이를 이용하여 다수의 청취자에게 동일하게 실감 있는 음장을 제공하기 위한 음장 재현 알고리즘을 제안한다. 제안된 알고리즘은 제어하고자 하는 3차원 공간 영역을 정의하고, 정의된 영역에서 원음장과 라우드스피커 어레이를 이용하여 재현되는 음장간의 자승오차가 최소가 되도록 라우드스피커 구동신호를 제어하는데 기초한다. 제안된 알고리즘의 성능을 검증하기 위하여 40개의 라우드스피커를 이용한 구형 3차원 어레이를 구성하였으며, 이를 이용한 실험결과와 고찰결과를 제시한다.

• Journal of Mechanical Science and Technology
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• 제17권11호
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• pp.1665-1673
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• 2003

We propose an image-based three-dimensional shape determination system. The shape, and thus the three-dimensional coordinate information of the 3-D object, is determined solely from captured images of the 3-D object from a prescribed set of viewpoints. The approach is based on the shape-from-silhouette (SFS) technique, and the efficacy of the SFS method is tested using a sample data set. The extracted three-dimensional shape is modeled with polygons generated by a new iterative triangulation algorithm, and the polygon model can be exported to commercial software. The proposed system may be used to visualize the 3-D object efficiently, or to quickly generate initial CAD data for reverse engineering purposes, including three dimensional design applications such as 3-D animation and 3-D games.

• Journal of information and communication convergence engineering
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• 제19권2호
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• pp.102-107
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• 2021

In this paper, we propose a new three-dimensional (3D) photon-counting integral imaging reconstruction method using a merging reconstruction process and maximum likelihood estimation (MLE). The conventional 3D photon-counting reconstruction method extracts photons from elemental images using a Poisson random process and estimates the scene using statistical methods such as MLE. However, it can reduce the photon levels because of an average overlapping calculation. Thus, it may not visualize 3D objects in severely low light environments. In addition, it may not generate high-quality reconstructed 3D images when the number of elemental images is insufficient. To solve these problems, we propose a new 3D photon-counting merging reconstruction method using MLE. It can visualize 3D objects without photon-level loss through a proposed overlapping calculation during the reconstruction process. We confirmed the image quality of our proposed method by performing optical experiments.

• Journal of International Society for Simulation Surgery
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• 제2권2호
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• pp.90-93
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• 2015

The fibula free flap has now become the most reliable and frequently used option for mandible reconstruction. Recently, three dimensional images and printing technologies are applied to mandibular reconstruction. We introduce our recent experience of mandibular reconstruction using three dimensionally planned fibula free flap in a patient with gunshot injury. The defect was virtually reconstructed with three-dimensional image. Because bone fragments are dislocated from original position, relocation was necessary. Fragments are virtually relocated to original position using mirror image of unaffected right side of the mandible. A medical rapid prototyping (MRP) model and cutting guide was made with 3D printer. Titanium reconstruction plate was adapted to the MRP model manually. 7 cm-sized fibula bone flap was designed on left lower leg. After dissection, proximal and distal margin of fibula flap was osteotomized by using three dimensional cutting guide. Segmentation was also done as planned. The fibula bone flap was attached to the inner side of the prebent reconstruction plate and fixed with screws. Postoperative evaluation was done by comparison between preoperative planning and surgical outcome. Although dislocated condyle is still not in ideal position, we can see that reconstruction was done as planned.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.63.3-63
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• 2001

Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. In this paper, we propose a three dimensional volume reconstruction method, which is an iterative method and as uniform and simulated algebraic reconstruction technique (USART). In this method, two or more x-ray images projected from different views are needed, and also the geometry of the imaging system need to be a priori identified well. That is to say, the relative locations between the x-ray source, imaging plane and the object should be determined exactly by calibration. To achieve this, we propose a series of coordinate calibration methods of the x-ray imaging system using grid pattern images. Some experimental results of these calibrations is presented and discussed in detail ...