• International Journal of Contents
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• 제5권4호
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• pp.30-34
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• 2009

Many studies have been done on the integral imaging pickup whose objective is to get efficiently elemental images from a lens array with respect to three-dimensional (3D) objects. In the integral imaging pickup process, it is necessary to render an elemental image from each elemental lens in a lens array for 3D objects, and then to combine them into one total image. The multiple viewpoint rendering (MVR) is one of various methods for integral imaging pickup. This method, however, has the computing and rendering time problem for obtaining element images from a lot of elemental lens. In order to solve the problems, in this paper, we propose a parallel MVR (PMVR) method to generate elemental images in a parallel through distribution of elemental lenses into multiple threads simultaneously. As a result, the computation time of integral imaging using PMVR is reduced significantly rather than a sequential approach and then we showed that the PMVR is very useful.

• Journal of Korean Neurosurgical Society
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• 제51권2호
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• pp.120-123
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• 2012

Objective : Percutaneous vertebroplasty (PVP) is usually carried out under three-dimensional (2D) fluoroscopic guidance. However, operative complications or bone cement distribution might be difficult to assess on the basis of only 2D radiographic projection images. We evaluated the feasibility of performing an intraoperative and postoperative examination in patients undergoing PVP by using three-dimensional (3D) reconstructive C-arm. Methods : Standard PVP procedures were performed on 14 consecutive patients by using a Siremobil Iso-$C^{3D}$ and a multidetector computed tomography machine. Post-processing of acquired volumetric datasets included multiplanar reconstruction (MPR) and surface shaded display (SSD). We analyzed intraoperative and immediate postoperative evaluation of the needle trajectory and bone cement distribution. Results : The male : female ratio was 2 : 12; mean age of patients, 70 (range, 77-54) years; and mean T score, -3.4. The mean operation time was 52.14 min, but the time required to perform and post-process the rotational acquisitions was 7.76 min. The detection of bone cement distribution and leakage after PVP by using MPR and SSD was possible in all patients. However, detection of the safe trajectory for needle insertion was not possible. Conclusion : 3D rotational image acquisition can enable intra- or post-procedural assessment of vertebroplasty procedures for the detection of bone cement distribution and leakage. However, it is difficult to assess the safe trajectory for needle insertion.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.113-120
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• 2004

Grouting works in fractured rocks have been performed to reinforce the underground and/or to block ground water flow at the foundation site of dam, bridge and so on. For the efficient grouting design, a prior knowledge of the fracture pattern of underground area to be grouted in very important. For the practical use, aperture sizes of open fractures that will be filled up with grouting materials will be kind of valuable information. Thus, the main purpose of this study is to develop a new technique (so called "GenFT") enable to form a three dimensional image of fracture aperture density distribution from Televiewer data. For this, the study is to focus on dealing with (1) estimating aperture size of each fracture automatically from Televiewer time image, (2) mapping extension of fracture planes on a given section, (3) evaluating aperture density distribution on the section by using both aperture size and fracture face mapping result of each fracture, (4) developing an algorithm that can transfer the previous results to any arbitrary(vertical and/or horizontal) section around the borehole. Since 3D imaging means "a strategy used to form an image of arbitrarily subdivided 2D sections with aperture density distribution", it will help avoid ambiguities of fracture pattern interpretation and hence will be of practical use not only for the design and assessment of grouting works but also for various engineering works. Examples of fields experiments are illustrated. It would seem that this technique might lead to reflecting future trend in underground survey.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 1999년도 제2회 학술발표회
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• pp.21-36
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• 1999

전기비저항 탐사는 국내에서 가장 성공적으로 적용되고 있는 물리탐사 기술의 하나로서 최근에는 토목 건설분야의 지반조사 등에서의 역할이 증대되고 있다. 이와 같은 역할의 증대에 따라 더욱 정확한 해석기법의 등장이 요구되었으며, 특히 국내의 경우 매우 복잡한 지질구조와 험난한 지형여건을 고려할 수 있는 해석기술이 요구되고 있다 이러한 맥락에서 최근에 3차원 전기비저항 탐사자료의 역산기술이 개발되었다. 개발된 3차원 전기비저항 역산법은 유한요소법을 이용한 3차원 전기비저항 모델링 알고리듬을 근간으로 함으로써 국내와 같이 험난한 지형 및 복잡한 지질구조에 대하여 정확한 지하구조의 3차원 영상을 제공할 수 있으며, 특히 ACB법 (Active Constraint Balancing method)의 채용으로 지하구조에 대한 분해능의 향상을 기대할 수 있게 되었다. 개발된 3차원 영상화 기술을 토대로 토목${\cdot}$건설분야의 지반조사에 3차원 전기비저항 탐사가 동원되고 있으며, 지반조사 대상지역에 있어서 중요한 지하구조에 대한 정보인 기반암 심도, 연약대 및 파쇄대 발달상황, 지하공동의 분포 등을 제공할 수 있었다.

• Journal of Magnetics
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• 제21권4호
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• pp.603-615
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• 2016

In this study, in order to determine the validity and accuracy of MR imaging of 3D gradient dual echo 2-point DIXON technique for measuring abdominal adipose tissue volume and distribution, the measurements obtained by CT were set as a reference for comparison and their correlations were evaluated. CT and MRI scans were performed on each subject (17 healthy male volunteers who were fully informed about this study) to measure abdominal adipose tissue volume. Two skilled investigators individually observed the images acquired by CT and MRI in an independent environment, and directly separated the total volume using region-based thresholding segmentation method, and based on this, the total adipose tissue volume, subcutaneous adipose tissue volume and visceral adipose tissue volume were respectively measured. The correlation of the adipose tissue volume measurements with respect to the observer was examined using the Spearman test and the inter-observer agreement was evaluated using the intra-class correlation test. The correlation of the adipose tissue volume measurements by CT and MRI imaging methods was examined by simple regression analysis. In addition, using the Bland-Altman plot, the degree of agreement between the two imaging methods was evaluated. All of the statistical analysis results showed highly statistically significant correlation (p<0.05) respectively from the results of each adipose tissue volume measurements. In conclusion, MR abdominal adipose volumetry using the technique of 3D gradient dual echo 2-point DIXON showed a very high level of concordance even when compared with the adipose tissue measuring method using CT as reference.

• 한국콘텐츠학회논문지
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• 제12권6호
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• pp.1-8
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• 2012

대부분 집적영상 기법에서는 사각형 렌즈 어레이가 사용되고 있으며, 이로 인해 집적된 빛의 분포는 사각격자 형태로 기록된다. 그러나 육각형 렌즈 어레이를 사용하면, 사각형 렌즈 어레이보다 더 높은 밀도의 빛의 분포와 이상적인 원형 렌즈에 가깝게 이미지를 기록 또는 재생 할 수 있다[4]. 육각형 렌즈 어레이 요소영상을 병렬 처리 기법을 사용하여 생성하기 위해서는 요소영상을 구성하는 각 화소에 대하여 그 화소가 속할 육각형 렌즈를 결정해야하고, 이 과정은 화면에 출력되는 모든 화소에 대하여 진행 되며 많은 계산량이 요구된다. 본 논문에서는 3D 볼륨 데이터를 사용하여 육각형 렌즈 어레이에 대한 요소영상을 생성하기 위해 OpenCL를 사용한 병렬 처리 기법을 제안한다. 제안 된 방법을 위한 실험에는 Male [$128{\times}256{\times}256$화소] 볼륨데이터를 사용하였으며, 실험 결과 $20{\times}20$개의 육각형 렌즈 어레이에 대해 요소영상을 초당 20~60장 생성할 수 있었다.

• 한국CDE학회논문집
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• 제15권4호
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• pp.297-305
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• 2010

Medical image acquisition techniques such as CT and MRI have disadvantages in that the numerous time and efforts are needed. Furthermore, a great amount of radiation exposure is an inherent proberty of the CT imaging technique, a number of side-effects are expected from such method. To improve such conventional methods, a number of novel methods that can obtain 3D medical images from a few X-ray images, such as algebraic reconstruction technique (ART), have been developed. Such methods deform a generic model of the internal body part and fit them into the X-ray images to obtain the 3D model; the initial shape, therefore, affects the entire fitting process in a great deal. From this fact, we propose a novel method that can generate a 3D vertebraic generic model based on the statistical database of CT scans in this study. Moreover, we also discuss a method to generate patient-tailored generic model using the facts obtained from the statistical analysis. To do so, the mesh topologies of CT-scanned 3D vertebra models are modified to be identical to each other, and the database is constructed based on them. Furthermore, from the results of a statistical analysis on the database, the tendency of shape distribution is characterized, and the modeling parameters are extracted. By using these modeling parameters for generating the patient-tailored generic model, the computational speed and accuracy of ART can greatly be improved. Furthermore, although this study only includes an application to the C1 (Atlas) vertebra, the entire framework of our method can be applied to other body parts generally. Therefore, it is expected that the proposed method can benefit the various medical imaging applications.

• 전자공학회논문지S
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• 제36S권1호
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• pp.104-114
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• 1999

본 논문에서능 2차원 칼라 동영상으로부터 3차원 개인 얼굴 모델을 자동 생성하는 효율적인 방법을 다루었다. 복잡한 배경이 포함된 영상에서 얼굴 영역을 안정적으로 추출하기 위하여 피부 색상 분포에 근거한 색상 움직임 추출 방법을 이용하였다. 검출된 얼굴 영역 내에서 색상 정보과 경계선 정보를 활용하여, MPEG-4의 SNHC(Synthetic-Natural Hybrid Coding) 에서 제안하고 있는 개개인의 얼굴 특성을 표현하는 31개의 얼굴 특징점 파라메타(Facial Description Rarameter: FDP)를 자동 추출하였다. 추출된 2차원 얼굴 특징점을 1038개의 삼각형 메쉬로 이루어진 3차원 일반 얼굴 모델(Generic model)에 적용시켜 변형함으로써 개개인의 얼굴에 해당하는 모델을 자동 생성하였다. 제안하는 알고리듬은 컬러 동영상에서 배경의 복잡성, 얼굴 크기 등에 상관없이 정면상에 가까운 경우 안정적인 특징점을 추출하였으며, 펜티엄 PC에서 약 2초 이내에 개개인의 얼굴 모습에 유사한 얼굴 모델을 생성할 수 있었다.

• 전자공학회논문지SC
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• 제45권2호
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• pp.1-7
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• 2008

본 논문에서는 원격 센싱이나 보안에 사용할 수 있는 밀리미터파 수동 이미징 센서를 제작하였다. 영상의 밝기 온도는 $3^{\circ}$의 분해능으로 안테나에서 측정된다. 제작한 센서는 PC에서 제어되며 pan/tilter 장치를 통해 빠른 성능을 얻는다. Pan/tilter 장치는 래스터 스캔을 통해서 2-D 영상을 스캔할 수 있다. 상하좌우로 기계적인 스캔에 의해서 $20{\times}20$ 픽셀의 영상은 400초 이내로 얻어진다. 영상은 측정 후 바로 표시되며 후처리를 위해 저장된다.

• 동의생리병리학회지
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• 제17권6호
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• pp.1493-1499
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• 2003

This study was examined for effects of acupuncture of Chok-Samni(ST36) on the facial thermography in health subjects, The volunteers who participating in this study had taken rest for 15 mins in room temperature (19-21 ℃) before the examination and informed them what to prohibit smoking, drinking and administration of drug for the previous day, The thermography of face was taken using Digital Infrared Thermographic Imaging (D.I.T.I. : Dorex, DTI-16UT1, U.S.A.) by time interval of 35 minutes at 15 min before and 20 min after acupuncture stimulation. Thermal temperature of Yangbaek(GB14), Myon-koryo(ST3) and Chichang(ST4) was measured and compared, The results showed that acupuncture of Chok-Samni(ST36) decreased the Absolute difference of temperature between Myon-koryo(ST3) and Chichang(ST4) (p<0,05, Data were represented mean±S,E.M.(n=33)), But, acupuncture of Chok-Samni(ST36) particularly decreased the absolute difference of temperature between Yangbaek(GB14) and Chichang(ST4) and particularly decreased the absolute difference of temperature between Vangbaek(GB14) and Myon-koryo(ST3) (p<0,05, Data were represented mean±S,E.M.(n=33)). Also, it was observed that acupuncture of Chok-Samni(ST36) decreased variety of the color tone of thermographic contour line and decreased thermal distribution. The results showed that acupuncture of Chok-5amni(ST36) significantly decreased the absolute difference of temperature of partial facial surface. Hereafter, study about if acupuncture of Chok-Samni(ST36) significantly decrease the absolute difference of temperature of all the areas of facial surface is requested. Also, continued study of effects of acupuncture of other meridian on the facial thermography is requested.