• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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• pp.140-147
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• 2007

As the use of robots in surgeries becomes more frequent, the registration of medical devices based on images becomes more important. This paper presents two numerical algorithms for the registration of cross-sectional medical images such as CT (Computerized Tomography) or MRI (Magnetic Resonance Imaging) by using the geometrical information from helix or line fiducials. Both registration algorithms are designed to be used for a surgical robot that works inside a cavity of human body. This paper also reports details about the fiducial pattern that includes four helices and one line. The algorithms and the fiducial pattern were tested in various computer-simulated situations, and the results showed excellent overall registration accuracy.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.714-719
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• 2004

This paper presents two numerical algorithms for registration of cross-sectional medical images such as CT (Computerized Tomography) or MRI (Magnetic Resonance Imaging) by using geometrical information from helix or line fiducials. The registration algorithms are designed to be used for a surgical robot working inside cavities of human body. A cylindrical device with a combination of line and helix fiducials were also devised and is supposed to be attached to the end-effector of surgical robot. The algorithms and the fiducial pattern were tested in various computer-simulated situations, and the results indicate excellent overall registration accuracy.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.04a
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• pp.429-432
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• 2000

일반사용자들이 쉽게 웹을 통하여 컴퓨터 그래픽스, 이미지(CT, MARI) 컴퓨터공학, 지리정보, 수치적 통계, 데이터분석 데이터를 그래픽으로 표현하고자 한다. VRML Visualization Server 구축하여 웹 기반 Visualizer 설계한다. 궁극적으로는 가시화의 실시간 표현에 있다. 모델링 기법에 있어서는 객체지향 그래픽 라이브러인 Visualization Toolkit을 이용하여 데이터의 Surface, Contour, Plane, Streamline, Probe 등을 구현하며, VRML 파일형태로 변환하여 클라이언트 웹으로 보내지게된다. 클라이언트 측 웹은 자신이 원하는 형태의 가시화 항목들을 선택하면 HTTP 에 의해 Visualization Server로 전송되어지고 Server의 ISAP는 전송되어져온 가시화항목을 가지고 가시화하여 VRML화일 형식으로 클라이언트 측으로 보내게된다.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.105-106
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• 2007

We present a fast reconstruction technique for elliptic objects, which can be applied to real-time computer tomography (CT) for simple geometric objects. It will be also shown that only 3 projections are needed to reconstruct an ellipse. A piecewise quadratic model is also proposed for more efficient Kalman filter based support estimation, which is used for the fast reconstruction technique. The performance of the piecewise quadratic model is compared with that of the existing piecewise linear model. Simulation results for the fast reconstruction are also presented.

• Korean Journal of Computational Design and Engineering
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• v.11 no.4
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• pp.265-272
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• 2006

For the design and analysis of 3D object featuring complexity and irregularity in shape, sectional digital images measured by an industrial CT scanner are employed to generate a finite element model with uniform voxels. The voxel model plays a key role in developing an integrated reverse engineering system including geometric modeling, simulation and optimization. Design examples applied to topology optimization show that the proposed approach can provide a remarkable reduction in time cost at the conceptual and detail design stages.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.827-833
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• 2023

CT(Computed Tomography) contrast agents are commonly used in general hospitals and university hospitals when taking radiographic examinations. The CT contrast medium contains a mixture of a substance called "Iodine", which absorbs radiation energy and makes it appear white in the CT image, further improving the image quality. In addition, the CT contrast agent, which moves like blood in the blood vessels, clearly differentiates it from muscle and water, so CT contrast agents are widely used in hospitals. These CT contrast agents absorb X-rays, but in order to absorb X-rays, they must have a high density or a high radiation absorption coefficient. Since the CT contrast agent is injected into the blood vessels, if the density is high, the blood vessels are strained and the patient is in shock. For this reason, it is necessary to match the density similar to that of water and always pay attention to side effects. In addition, the amount of CT contrast medium is adjusted according to the patient's body shape, and the remaining contrast medium is discarded. However, This study tried to find out the idea of recycling it as a radiation shielding material. Since the CT contrast medium has a high radiation absorption coefficient at a density similar to that of water, the amount to absorb radiation is adjusted, the amount of contrast medium and the amount of water are adjusted, and the amount of radiation absorbed is determined by mixing with water. In addition, a study was conducted to find out the result of the difference in radiation absorption in various ways by comparing the radiation quality coefficient and absorption coefficient with other substances or materials in an environmentally friendly method harmless to the human body by mixing CT contrast medium and water.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.351-361
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• 2012

The leading surgical method for correcting the misalignment of the varus and valgus in the knee joint is the high tibial osteotomy (HTO). In the opening wedge HTO (OWHTO), there is no concern about damaging the peroneal nerve on the lateral tibia of the proximal fibula. OWHTO has been the preferred choice, as the opening of the correction angle can be modulated during the operation. The correction of the varus and valgus on the coronal plane are performed adroitly. Nevertheless, there have been numerous reports of unintended changes in the medial tibial plateau and posterior slope angle (PSA). The authors have developed an HTO method using computer-assisted surgery with the aim of addressing the abovementioned problems from an engineer's perspective. CT images of the high tibia were reconstructed three-dimensionally, and a virtual osteotomy was performed on a computer. In addition, this study recommends a surgical method that does not cause changes in the PSA after OWHTO. The results of the study are expected to suggest a clear relationship between the anteromedial cortex oblique angle of each patient and the PSA, and an optimal PSA selection method for individuals.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.63-69
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• 2023

In head and neck radiation therapy, the thermoplastic immobilization mask used for fixing the patient's posture and reproducibility causes scattered rays by being in close contact with the skin. To investigate the increase in skin dose due to the scattered rays generated from the immobilization mask, we evaluated dose reduction by decreasing contact between face skin and immobilization mask in computerized radiotherapy planning system with CT scanned images. In addition, to confirm the reproducibility problem of the setup due to the decrease in the cover area of immobilizing, the difference of each setup was confirmed using DRR and CT images. As the mask area covered for immobilizing was reduced, the dose on the skin surface significantly decreased, and it was confirmed that there was no significant difference in reproducibility even if the entire face was not covered and fixed.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.11
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• pp.305-310
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• 2021

Artificial intelligence technology in the medical field initially focused on analysis and algorithm development, but it is gradually changing to web application development for service as a product. This paper describes a Urinary Stone segmentation model in abdominal CT images and an artificial intelligence web application based on it. To implement this, a model was developed using U-Net, a fully-convolutional network-based model of the end-to-end method proposed for the purpose of image segmentation in the medical imaging field. And for web service development, it was developed based on AWS cloud using a Python-based micro web framework called Flask. Finally, the result predicted by the urolithiasis segmentation model by model serving is shown as the result of performing the AI web application service. We expect that our proposed AI web application service will be utilized for screening test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3054-3059
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• 2009

Natural black diamonds of single crystal, polycrystalline, and agglomerated roughs become important for their industrial and gem stone application. We performed the conventional gemological tests of thermal diffusion, apparent density, scratch test, and magnification test as well as the advanced tests of Raman spectroscopy, X-ray diffraction test and Lang topography. We conclude that scratch test with SiC paper was the most efficient method in view point of speed and cost. Raman spectroscopy and XRD were useful for identification of diamond while Lang topography offered a good visualization method of the grain structure of polycrystalline black diamond roughs.