• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.23-26
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• 2019

본 논문에서는 X-Ray 영상에서 용접한 부분의 기공이나 균열 등의 결함 영역을 추출하는 새로운 방법을 제안한다. 제안된 방법은 세라믹 X-Ray 영상에서 비등방성 확산 필터를 적용하여 영상의 잡음을 제거하고, 수직 및 수평 히스토그램을 각각 적용하여 용접 영역을 추출한 후, 최소 자승법을 적용하여 배경 밝기를 제거하고, 사다리꼴 형태의 Fuzzy Stretching기법을 적용하여 명암 값을 강조하여 결함 영역과 그 외의 영역간의 명암 대비를 강조한다. 그리고 Fuzzy C_Means 알고리즘을 적용하여 결함 영역을 세분화한 후, Fuzzy C_Means을 적용하여 생성된 클러스터들의 중심 명암 값을 이용하여 ${\alpha}_-cut$을 설정한 후에 임계구간을 구하고 영상을 이진화하여 최종적으로 결함 영역을 추출한다. 제안된 방법의 결함 추출 성능을 확인하기 위하여 세라믹 X-Ray 영상을 대상으로 실험한 결과, 기존의 방법보다 결함 영역이 정확히 추출되는 것을 확인할 수 있었다.

• Journal of the Korean Society of Radiology
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• v.84 no.6
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• pp.1414-1420
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• 2023

In adults, spinal ependymomas are usually found in intramedullary locations. However, intradural extramedullary spinal ependymomas are rare. Additionally, spinal ependymomas usually show iso to hypointensity on T1-weighted images without hemorrhage. Herein, we present a rare case of a 43-year-old female with a pathologically confirmed intradural extramedullary ependymoma that showed hyperintensity on T1-weighted imaging accompanied by hemorrhage.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.160-163
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• 2002

본 연구는 의료영상 중에 가장 많이 사용하는 의료 영상인 MR영상 중에서 머리 부위의 질병인 뇌종양에 대한 진단을 돕기 위한 연구이다. 뇌 MR영상의 T2강조 영상을 살펴보면, 종양 영역은 명암이 밝게 나타나고 종양 영역의 주변은 어둡게 나타나는 특성을 볼 수 있다. 따라서 제안된 방법은 뇌종양 특성인 명암의 밝기 정보를 기반으로 비정상 영역 내에서 명암 정보가 유사한 영역끼리 그룹화하고 그 중에 가장 밝은 영역을 종양 후보 영역으로 추출한 후 각 후보 영역들 중에서 MBR이 가장 큰 것을 종양으로 검출한다.

• The KIPS Transactions:PartB
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• v.13B no.2 s.105
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• pp.77-82
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• 2006

Digital halftoning is the technique to obtain a bilevel-toned image from continuous-toned image. Among halftoning methods, the error diffusion method gives better subjective quality than other halftoning ones. But it also makes edges of objects blurred. To overcome the defect, we proposes the modified error diffusion to enhance the edges using the property that human vision perceives the local average luminance and doesn't perceive a little variation of the spatial variation. The proposed method computes a spatialactivity, which is the difference between a pixel luminance and the average of its $3{\times}3$ neighborhood pixels' Iuminance weighted according to the spatial positioning. The system also usesof edge enhancement (IEE), which is computed from the normalized spatial activitymultiplied by the average luminance. The IEE is added to the quantizer's input pixel and feeds into the halftoning quantizer. The quantizer produces the halftone image having the enhanced edge. The computer experimental results show that the proposed method produces clearer bilevel-toned images than conventional methodsand the edge of objects is preserved well. Also the performance of the preposed method is improved, compared with that of the conventional method by measuring the edge correlation and the local average accordance at some ranges of viewing distance.

• Investigative Magnetic Resonance Imaging
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• v.17 no.1
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• pp.1-7
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• 2013

Purpose : The purpose of this study is to correlate the imaging findings and the clinical findings in patients with transient splenial lesions (TSL). Materials and Methods: Total of 7 patients (M: F = 4: 3; age range 11 - 38 years, mean age 25.5 years) were studied between November 2006 and April 2011. The MRI findings and clinical findings in all patients were retrospectively reviewed. The location, MR signal intensity, restricted diffusion, enhancement pattern and reversibility from the follow up images were reviewed. Clinical features were reviewed with respect to the presented symptoms, signs, treatment and outcome. Results: The lesions were located in the splenium of corpus callosum in all patients. All lesions showed high signal intensity on diffusion weighted imaging (DWI), and six patients showed restricted diffusion on the apparent diffusion coefficient (ADC) map. ADC map was not available in one patient. All lesions (n = 7) showed high signal intensity on the T2 weighted image (T2WI). Five of the patients (71.4%) with follow up images (range 7 - 34 days) showed complete resolution of focal high signal intensity on DWI, with recovery of ADC values as well as T2WI. After contrast media administration, none of the lesions showed any enhancements. All lesions with various etiologies including TB medication were developed in younger age patients and showed reversibility after the acceptable period of minimum 7 days with conservative treatment. Conclusion: All TSL showed nonspecific imaging findings, including restricted diffusion on DWI and ADC map on the initial images. However, reversibility of the lesions and the young age preference can be a characteristic finding of TSL with acceptable period of minimum 7 days. In addition, to keep it in mind that various etiologies including TB medication may cause TSL, is important for radiologists as well as clinicians.

• Journal of Digital Convergence
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• v.11 no.1
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• pp.361-368
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• 2013

The purpose of this study is to know the clinical usefulness of optimal b-values by quantitative, qualitative evaluation of DW-MRI for lesions of benignity and malignity of female pelvis. The b-values used in DWI were 600, 800, 1000, 1200, 1400($s/mm^2$). Mean SNR and CNR of myoma in b-value 800 were the highest result as $84.6{\pm}4.57$(p=0.024) and $50.13{\pm}5.47$(p=0.028), Mean SNR and CNR of cervical cancer were the highest result as $12.0{\pm}2.04$(p=0.047) and $10.6{\pm}1.24$(p=0.001), Mean ADC value in myoma and cervical cancer in b-value 800 were $1.19{\times}10^{-3}mm^2/s$(p=0.008), $0.96{\times}10^{-3}mm^2/s$(p=0.027). As a qualitative analysis, the delineation and conspicuity were the highest result as $4.02{\pm}0.18$(p=0.028), $4.39{\pm}0.25$(p=0.015) on b-value 800. DW-MRI is an important method, and the optimal b values is 800 $s/mm^2$ for differentiation between benign and malignant lesions of female pelvis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.485-487
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• 2015

본 논문에서는 애견의 안구 영상을 분석하여 백내장을 추출하는 방법을 제안한다. 제안된 방법은 애견의 영상에서 안구 영역을 선택한 후, 양선형 보간법을 적용하여 선택된 안구 영역을 확대한 후, 퍼지 스트레칭 기법을 적용하여 명암 대비를 강조한다. 강조된 영상에서 이진화 기법과 침식, 팽창기법을 적용하여 잡음 영역을 제거한다. 잡음이 제거된 안구 영역에 8 방향 윤곽선 추적 기법을 적용하여 백내장을 추출한다. 추출된 백내장 부분을 애견의 평균적인 백내장의 크기와 비교 분석하여 백내장 가능성을 도출한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.87-89
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• 2013

본 논문에서는 Ends-In Search Stretching 기법을 적용하여 명암 대비를 강조하고, 명암 대비가 강조된 영상에서 삼각형 타입의 소속 함수를 이용한 퍼지 이진화 기법을 적용한 후, 그 다음 임의의 패턴 입력에 대해서도 효과적으로 특징을 분류하는 개선된 ART2 알고리즘을 이용하여 결함 영역을 검출한다. 제안된 방법을 세라믹 소재 영상을 대상으로 실험한 결과, 기존의 방법보다 효율적으로 결함이 검출되는 것을 확인하였다.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.72-76
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• 2011

Solitary fibrous tumor (SFT) is a rare neoplasm, which is usually presented as a pleural based mass, but can also occur in unusual locations based on its mesenchymal origin. However, the radiologic features of SFT occurred in the ischiorectal fossa have been rarely reported. In this case, we describe the MRI findings in a case of a SFT involving the ischiorectal fossa of a 36-year-old man. The tumor appeared as homogeneous iso-signal intensity relative to the adjacent muscle on T1 weighted images, a mixed high signal intensity on the T2 weighted images, and heterogeneous enhancement following the administration of the contrast material.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.243-251
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• 2004

This study was to quantitative analysis compare to dynamic characteristic change of the regional cerebral blood volume (rCBV) after development of cerebral fat embolism in cats using perfusion MR Imaging. Forty-four adult rats were used. Triolein (n = 15), oleic acid (n = 9) and linoleic acid (n = 11) were injected into the internal carotid artery using microcatheter through the transfemoral approach. Polyvinyl alcohol (Ivalon) (n = 9) was injected as a control group. Perfusion MR images were obtained at 30 minutes and 2 hours after embolization, based on T2 and diffusion-weighted images. The data was time-to-signal intensity curve and ΔR$_2$＊ curve were obtained continuously with the aid of home-maid image proc in.leased significantly at 2 hours compared with those of 30 minutes (P＜0.005). In conclusion, cerebral blood flow decreased in cerebral fat embolism immediately after embolization and recovered remarkably in time course. It is thought that clinically informations to dynamic characteristic change of the cerebral hemodynamics to the early finding in cerebral infarction by DWI and PWI