• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.2037-2042
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• 2012

Synthetic aperture integral imaging is one of promising 3D imaging techniques to capture the high-resolution elemental images using multiple cameras. In this paper, we propose a method of displaying 3D images in space using the synthetic aperture integral imaging technique. Since the elemental images captured from SAII cannot be directly used to display 3D images in an integral imaging display system, we first extract the depth map from elemental images and then transform them to novel elemental images for 3D image display. The newly generated elemental images are displayed on a display panel to generate 3D images in space. To show the usefulness of the proposed method, we carry out the preliminary experiments using a 3D toy object and present the experimental results.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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• pp.22-25
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• 1992

Lipid component and water component image in living organism can be acquired due to its chemical shift difference. Various techniques for chemical shift imaging were used for acquiring separated image. It is necessary two imaging experiments to acquire two separated images wi th Dixon's method. This technique is less susceptible to local magnetic inhomogeneities and easily applied to multi-slice imaging. With CHESS and SECSI method, which based on chemical selectivity of R.F pusle, either water or lipid image can be acquired by one imaging experiment. However, those are more susceptible to local magnetic field inhomogeneities and difficult to apply to multi-slice imaging. The SECSI method showed best signal suppression ratio of fat and water, which is measure of separation of water and fat.

• Journal of Biomedical Engineering Research
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• v.27 no.3
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• pp.110-116
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• 2006

Finite element method (FEM) provides several advantages over other numerical methods such as boundary element method, since it allows truly volumetric analysis and incorporation of realistic electrical conductivity values. Finite element mesh generation is the first requirement in such in FEM to represent the volumetric domain of interest with numerous finite elements accurately. However, conventional mesh generators and approaches offered by commercial packages do not generate meshes that are content-adaptive to the contents of given images. In this paper, we present software that has been implemented to generate content-adaptive finite element meshes (cMESHes) based on the contents of MR images. The software offers various computational tools for cMESH generation from multi-slice MR images. The software named as the Content-adaptive FE Mesh Generation Toolbox runs under the commercially available technical computation software called Matlab. The major routines in the toolbox include anisotropic filtering of MR images, feature map generation, content-adaptive node generation, Delaunay tessellation, and MRI segmentation for the head conductivity modeling. The presented tools should be useful to researchers who wish to generate efficient mesh models from a set of MR images. The toolbox is available upon request made to the Functional and Metabolic Imaging Center or Bio-imaging Laboratory at Kyung Hee University in Korea.

• Journal of Biomedical Engineering Research
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• v.15 no.4
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• pp.377-382
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• 1994

In the conventional Fourier imaging method in MRI (Magnetic Resonance Imaging), intramotion such as pulsatile flow makes zipper-like artifact along the phase encoding direction. On the other hand, line-integral projection reconstruction (LPR) method has advantages such as imaging of short T2, object and reduction of the flow artifact by elimination of the flow-induced phase fluctuation. The LPR, however, necessarily requires time consuming filtering and back-projection processes, so that the reconstruction takes long time. To overcome the long reconstruction time of the LPR and to obtain the flow artifact reduction effect, we adopted phase corrected concentric square raster sampling (CSRS) method and improved its imaging performance. The CSRS is a fast reconstruction method which has the same properties with the LPR. In this paper, we proposed a new method of flow artifact reduction using the CSRS method. Through computer simulations and experiments, we verified that the proposed method can eliminate phase fluctuations, thereby reducing the flow artifact and re- markably shorten the reconstruction time which required long time in the LPR.

• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.381-388
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• 2016

The performance of a staring infrared imaging system can be characterized based on estimating the modulation transfer function (MTF). The slant edge method is a widely used MTF estimation method, which can effectively solve the aliasing problem caused by the discrete undersampling of the infrared focal plane array. However, the traditional slant edge method has some limitations such as the low precision of the edge angle extraction and using the approximate function to fit the edge spread function (ESF), which affects the accuracy of the MTF estimation. In this paper, we propose a modified slant edge method, including an edge angle extraction method that can improve the precision of the edge angle extraction and an ESF fitting algorithm which is based on the transfer function model of the imaging system, to enhance the accuracy of the MTF estimation. This modified slant edge method presents higher estimation accuracy and better immunity to noise and edge angle than other traditional methods, which is demonstrated by the simulation and application experiments operated in our study.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.193-199
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• 2006

Infectious and inflammatory bone diseases include a wide range of disease process, depending on the patient's age, location of infection, various causative organisms, duration from symtom onset, accompanied fracture or prior surgery, prosthesis insertion, and underlying systemic disease such as diabetes, etc. Bone infection may induce massive destruction of bones and joints, results in functional reduction and disability. The key to successful management is early diagnosis and proper treatment. Various radionuclide imaging methods including three phase bone scan, Ga-67 scan, WBC scan, and combined imaging techniques such as bone/Ga-67 scan, WBC/bone marrow scan add complementary role to the radiologic imaging modalities including plain radiography, CT and MRI. F-18 FDG PET imaging also has recently been introduced in diagnosis of infected prosthesis and chronic active osteomyelitis. Selection of proper nuclear medicine imaging method will improve the diagnostic accuracy of infections and inflammatory bone diseases, based on understading of pathogenesis and radiologic imaging findings.

• Journal of Chest Surgery
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• v.52 no.4
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• pp.205-220
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• 2019

Near-infrared (NIR) fluorescence imaging provides a safe and cost-efficient method for immediate data acquisition and visualization of tissues, with technical advantages including minimal autofluorescence, reduced photon absorption, and low scattering in tissue. In this review, we introduce recent advances in NIR fluorescence imaging systems for thoracic surgery that improve the identification of vital tissues and facilitate the resection of tumorous tissues. When coupled with appropriate NIR fluorophores, NIR fluorescence imaging may transform current intraoperative thoracic surgery methods by enhancing the precision of surgical procedures and augmenting postoperative outcomes through improvements in diagnostic accuracy and reductions in the remission rate.

• Imaging Science in Dentistry
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• v.50 no.4
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• pp.273-279
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• 2020

This review presents an overview of some diagnostic imaging-related issues regarding medication-related osteonecrosis of the jaws(MRONJ), including imaging signs that can predict MRONJ in patients taking antiresorptive drugs, the early imaging features of MRONJ, the relationship between the presence or absence of bone exposure and imaging features, and differences in imaging features by stage, between advanced MRONJ and conventional osteomyelitis, between oncologic and osteoporotic patients with MRONJ, and depending on the type of medication, method of administration, and duration of medication. The early diagnosis of MRONJ can be made by the presence of subtle imaging changes such as thickening of the lamina dura or cortical bone, not by the presence of bone exposure. Most of the imaging features are relatively non-specific, and each patient's clinical findings and history should be referenced. Oral and maxillofacial radiologists and dentists should closely monitor plain radiographs of patients taking antiresorptive/antiangiogenic drugs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.5103-5115
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• 2015

In radar imaging, a target is usually consisted of a few strong scatterers which are sparsely distributed. In this paper, an improved sparse signal recovery algorithm based on smoothed l₀ (SL0) norm method is proposed to achieve high resolution ISAR imaging with limited pulse numbers. Firstly, one new smoothed function is proposed to approximate the l₀ norm to measure the sparsity. Then a single loop step is used instead of two loop layers in SL0 method which increases the searching density of variable parameter to ensure the recovery accuracy without increasing computation amount, the cost function is undated in every loop for the next loop until the termination is satisfied. Finally, the new set of solution is projected into the feasible set. Simulation results show that the proposed algorithm is superior to the several popular methods both in terms of the reconstruction performance and computation time. Real data ISAR imaging obtained by the proposed algorithm is competitive to several other methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5095-5111
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• 2019

A multi-rotor Unmanned Aerial Vehicle (UAV) system is developed to solve the manhole cover detection problem for the infrastructure maintenance in the suburbs of big city. The visible light sensor is employed to collect the ground image data and a series of image processing and machine learning methods are used to detect the manhole cover. First, the image enhancement technique is employed to improve the imaging effect of visible light camera. An imaging environment perception method is used to increase the computation robustness: the blind Image Quality Evaluation Metrics (IQEMs) are used to percept the imaging environment and select the images which have a high imaging definition for the following computation. Because of its excellent processing effect the adaptive Multiple Scale Retinex (MSR) is used to enhance the imaging quality. Second, the Single Shot multi-box Detector (SSD) method is utilized to identify the manhole cover for its stable processing effect. Third, the spatial coordinate of manhole cover is also estimated from the ground image. The practical applications have verified the outdoor environment adaptability of proposed algorithm and the target detection correctness of proposed system. The detection accuracy can reach 99% and the positioning accuracy is about 0.7 meters.