• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.91-98
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• 2009

Recent digital camera development tendency shows the higher ISO extension which enables a user to take a picture in deemed lighting condition without using a flash or another equipment. Also noise reduction function has been developed to adjust the higher ISO extension. But using the high ISO causes a lot of noises so that proper noise reduction function should be adjusted. So the manufacturers introduce the advanced noise reduction function with higher ISOs as the digital camera performance development. On the other hands, the defect of noise reduction is not widely open such as remaining noise in high ISOs and decreasing resolution. Therefore, in this research we verify and experiment the decrease of resolution by using noise reduction function on a digital camera. Moreover we analyze the results how much the noise reduction function effects to the image resolution. And we present the results as practical numerical values.

• Journal of the Korea Society of Computer and Information
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• v.17 no.7
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• pp.53-65
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• 2012

Existing method of creating Stereoscopy image, creates viewpoint image from the left and right by shooting one object with 2 lens in certain distance. However, in case of 3-D TV using Stereoscopy camera, the necessity to transmit 2 viewpoint images from the left and right simultaneously, increases the amount of bandwidth. Various and more effective alternatives are under discussion. Among the alternatives, DIBR(Depth Image Based Rendering) creates viewpoint images from the left and right using one image and its Depth information, thus decreasing the amount of transmitted bandwidth. For this reason, there have been various studies on Algorithm to create DIBR Image in existing Static Scene. In this paper, I would like to suggest Gaussian Hole-filling solution, which utilizes reverse-depth image to fill the hole naturally, while minimizing distortion of background. In addition, we have analyzed the effectiveness of each Algorithm by comparing and calculating its functions.

• Korean Journal of Remote Sensing
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• v.19 no.6
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• pp.431-445
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• 2003

In this paper, we experimentally investigated the precision of 3D positioning using 4S-Van images in photograrmmetric perspective. The 3D calibration target was built over building facade outside and was captured separately by two CCD cameras installed in 4S-Van. After then, we determined the interior orientation parameter for each CCD camera through self-calibration technique. With the interior orientation parameter computed, the bundle adjustment was performed to obtain the exterior orientation parameters simultaneously for two CCD cameras using calibration target image and object coordinates. The reverse lens distortion coefficients were computed and acquired by least squares method so as to introduce lens distortion into epipolar line. It was shown that the reverse lens distortion coefficients could transform image coordinates into lens distorted image coordinates within about 0.5 pixel. The proposed semi-automatic matching scheme incorporated with lens distorted epipolar line was implemented with scene images captured by 4S-Van in moving. The experimental results showed that the precision of 3D positioning from 4S-Van images in photograrmmetric perspective is within 2cm in the range of 20m from the camera.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.93-96
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• 2010

This study evaluates usefulness of the developed assistant device by taking projection of patellofemoral joint in emergency patients who were doubt posterior cruciate ligament injury in knee joint. The subjects of experiment were patients who visited Eul-Ji University Hospital due to knee injury from January 2006 to December 2006. Seventeen patients, who took the Knee post stress view, Knee merchant view, Knee Seo's view to use assistant device and Knee MRI. To make assistant device of $170{\times}50{\times}70\;cm$, we evaluated its usefulness by measuring posterior dislocation of tibia. Seo's view is more accurate to make judgment of posterior cruciate ligament injury than original knee post stress view. Interval difference of posterior dislocation of original knee post stress view is $6.17{\pm}3.04$ and Seo's view is $8.74{\pm}4.47$. The results show injury of patellofemoral joint, vertical fracture of patella and posterior cruciate ligament injury by taking a projection using Seo's view. Therefore, it is useful to take projection earlier than talometer and MRI in emergency patients who were doubt posterior cruciate ligament injury in knee joint.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.108-115
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• 2003

Purpose : To evaluate the effect of the gradient switching noise on the ECD source localization with the EEG data recorded during the MRI scan. Materials and Methods : We have fabricated a spherical EEG phantom that emulates a human head on which multiple electrodes are attached. Inside the phantom, electric current dipole(ECD) sources are located to evaluate the source localization error. The EEG phantom was placed in the center of the whole-body 3.0 Tesla MRI magnet, and a sinusoidal current was fed to the ECD sources. With an MRI-compatible EEG measurement system, we recorded the multi channel electric potential signals during gradient echo single-shot EPI scans. To evaluate the effect of the gradient switching noise on the ECD source localization, we controlled the gradient noise level by changing the FOV of the EPI scan. With the measured potential signals, we have performed the ECD source localization. Results : The source localization error depends on the gradient switching noise level and the ECD source position. The gradient switching noise has much bigger negative effects on the source localization than the Gaussian noise. We have found that the ECD source localization works reasonably when the gradient switching noise power is smaller than $10\%$ of the EEG signal power. Conclusion : We think that the results of the present study can be used as a guideline to determine the degree of gradient switching noise suppression in EEG when the EEG data are to be used to enhance the performance of fMRI.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.483-489
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• 2015

In this paper, we propose monocular visual simultaneous localization and mapping (SLAM) in the large-scale environment. The proposed method continuously computes the current 6-DoF camera pose and 3D landmarks position from video input. The proposed method successfully builds consistent maps from challenging outdoor sequences using a monocular camera as the only sensor. By using a binary descriptor and metric-topological mapping, the system demonstrates real-time performance on a large-scale outdoor dataset without utilizing GPUs or reducing input image size. The effectiveness of the proposed method is demonstrated on various challenging video sequences.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.519-529
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• 2013

This paper introduces a moving object tracing system using network-connected CCTV and smartphone. In an emergency situation, a smartphone of the reporter gains its GPS information and sends that to the central server. The central server stores received GPS information as a dangerous area in the database and keeps sending the order of tracing the reporter to a network-connected CCTV which can film the reporter. At the same time, the central server sends pictures of the reporter to his or her family and related organization in order to handle the emergency situation as soon as possible. In addition, when a reporter want to know the risk around destination, the central server informs dangerous areas to the reporter by using smart phone application and database of a danger spot.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.3
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• pp.331-341
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• 2002

In order to extract 3-dimensional information from 2-D image, stereo images are prerequisite. Moreover, for the measurement of moving objects, the synchronized sequential stereo images have to be captured and image matching should be implemented for determining the location of moving objects. In this research, a simple method computing 3-dimensional coordinates from sequential images of moving objects was implemented. The sequential stereo images were captured by a video camera with a beam splitter. Once video images were digitalized by frame grabber, the interest points were extracted and matched in each stereo image, and the coordinates of center of them are calculated using weighted average method. Then, 3-dimensional coordinates of moving objects were computed by DLT algorithms.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.350-356
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• 2015

The aim of this study is to perform simulations to design the detector module with crystal array by Monte Carlo simulation. For this purpose, a small animal PET scanner, employing module with 1~8 crystal array discrimination scheme, was designed. The proposed scanner has an inner diameter of 100 mm with detector modules in crystal array. Each module is composed of a 5.0 mm LSO crystal with a $2.0{\times}2.0mm^2$ sensitive area with a pitch 2.1 mm and 10.0 mm thickness. The LSO crystals are attached to the SiPM which has a dimension of $2.0{\times}2.0mm^2$. The detector module with crystal array of the designed PET detector was simulated using the Monte Carlo code GATE(Geant4 Application for Tomographic Emission). The detector is enough compensation for the loss of data in sinogram due to gaps between modules. The results showed that the high sensitivity and effectively reduced the problem about the missing data were greatly improved by using the detector module with 1 crystal array.

• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.195-207
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• 1998

폐암을 집단 검진으로 조기 진단하려는 노력은 현재까지 뚜렷한 성과를 얻지 못하고 있는 실정이다. 미국의 국립암연구소에서 실시한 흉부엑스선 촬영과 객담세포진 검사를 이용한 폐암의 집단 검진 결과는 검진군에서 대조군보다 유의하게 진단율이 높았으며 절제율도 더 높았고 5년 생존율도 향상시킬 수 있었다. 그러나 폐암을 조기 진단하기 위한 집단 검진의 궁극적인 목표인 사망률을 감소시키지는 못하였다. 최근에는 미국 국립암 연구기관에서 실시했던 결과에 대한 해석이 다양하여 아직까지도 폐암 조기 진단에 있어서 흉부액스선촬영과 객담세포진검사의 의의에 관한 결론에 대해서는 논란이 되고 있다. 1993년부터 새로운 집단 검진에 관한 연구가 진행중에 있어서 그 결과가 나올 때까지는 흉부엑스선촬영과 객담세포진검사를 이용한 집단 검진의 의의에 대한 결과는 기다려 보아야 할 것이다. 분자생물학적으로 폐암을 조기 검진하기 위한 검체로는 혈액보다는 객담이 훨씬 적절하고 합리적인 검체이다. 폐암의 발생은 가장 먼저 기관지 상피 세포에서 일어나서 암화 과정의 여러 단계에서 다양한 종양 표지자가 객담에 섞여 나오기 때문에 이 표지자를 객담에서 측정하는 것이 훨씬 합리적인 조기 진단법이 될 수 있다. 동시에 폐암을 집단 검진으로 조기 진단하기 위해서는 종양 표지자를 대량으로 측정하기 위한 자동측정법도 개발되어야 할 것이다. 암을 예방하기 위하여는 여러면에서 방안이 연구되어야 한다. 즉 암발생의 가능성이 높은 대상을 선태하여야 하며 초기에 집단 검진으로 진단을 할 수 있어야 하고, 이러한 검진으로 추적 검사가 가능하여야 하며 마지막으로 결과를 판정할 수 있어야 한다. 이 가운데 현재까지 유일하게 실시할 수 없는 것은 조기 진단으로 사용할 수 있는 뚜렷한 종양 표지자가 없는 것이다. 이와 같이 현재까지는 폐암을 조기 진단하기 위한 특이한 표지자는 없으나 앞으로 폐암 발생 기전의 여러 단계가 체계적으로 밝혀진다면 그 과정에서 중요한 표지자들이 밝혀질 것이다. 그리고 이들을 간단하게 검사할 수 있는 검사법도 밝혀져 폐암 조기 진단의 궁극적 목적인 폐암으로 인한 사망률을 감소시킬 수 있을 것으로 기대된다.