• 한국멀티미디어학회논문지
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• 제24권2호
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• pp.178-185
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• 2021

Three-dimensional high-resolution magnetic resonance imaging (MRI) provides fine-level anatomical information for disease diagnosis. However, there is a limitation in obtaining high resolution due to the long scan time for wide spatial coverage. Therefore, in order to obtain a clear high-resolution(HR) image in a wide spatial coverage, a super-resolution technology that converts a low-resolution(LR) MRI image into a high-resolution is required. In this paper, we propose a super-resolution technique through filter learning based on information on the surrounding gradient information in 3D space from 3D MRI images. In the learning step, the gradient features of each voxel are computed through eigen-decomposition from 3D patch. Based on these features, we get the learned filters that minimize the difference of intensity between pairs of LR and HR images for similar features. In test step, the gradient feature of the patch is obtained for each voxel, and the filter is applied by selecting a filter corresponding to the feature closest to it. As a result of learning 100 T1 brain MRI images of HCP which is publicly opened, we showed that the performance improved by up to about 11% compared to the traditional interpolation method.

• 한국가시화정보학회지
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• 제20권3호
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• pp.10-18
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• 2022

We present an experimental investigation on emulsions created during the impact process between a surfactant-laden droplet and an oil layer on water. By varying the surfactant concentration and the viscosity of oil layer, we created emulsions and visualized them using multi-dimensional high-speed imaging. Our analysis shows that the emulsions are more likely to be unstable and decay within a minute if the impacting droplet contains more surfactant. We also found that there are three mechanisms of generation of emulsions depending on the concentration of surfactant and the viscosity of oil layer; the jet pinch-off, cavity pinch-off, and tearing of oil layer. Jet and cavity pinch-off turned out to be dominant mechanisms for high oil viscosities, while tearing of oil layer is dominant for low oil viscosities. Our result is potentially useful in designing optimal dispersant properties for offshore oil contamination.

• ETRI Journal
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• 제45권1호
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• pp.131-137
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• 2023

The phase reconstruction process in digital holographic microscopy involves a trade-off between the phase error and the high-spatial-frequency components. In this reconstruction process, if the narrow region of the sideband is windowed in the Fourier domain, the phase error from the DC component will be reduced, but the high-spatial-frequency components will be lost. However, if the wide region is windowed, the 3D profile will include the high-spatial-frequency components, but the phase error will increase. To solve this trade-off, we propose the high-variance pixel averaging method, which uses the variance map of the reconstructed depth profiles of the windowed sidebands of different sizes in the Fourier domain to classify the phase error and the high-spatial-frequency components. Our proposed method calculates the average of the high-variance pixels because they include the noise from the DC component. In addition, for the nonaveraged pixels, the reconstructed phase data created by the spatial frequency components of the widest window are used to include the high-spatialfrequency components. We explain the mathematical algorithm of our proposed method and compare it with conventional methods to verify its advantages.

• 천문학회지
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• 제56권2호
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• pp.149-157
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• 2023

The propagation speed of a circumstellar pattern revealed in the plane of the sky is often assumed to represent the expansion speed of the wind matter ejected from a post-main-sequence star at the center. We point out that the often-adopted isotropic wind assumption and the binary hypothesis as the underlying origin for the circumstellar pattern in the shape of multilayered shells are, however, mutually incompatible. We revisit the hydrodynamic models for spiral-shell patterns induced by the orbital motion of a hypothesized binary, of which one star is losing mass at a high rate. The distributions of transverse wind velocities as a function of position angle in the plane of the sky are explored along viewing directions. The variation of the transverse wind velocity is as large as half the average wind velocity over the entire three dimensional domain in the simulated models investigated in this work. The directional dependence of the wind velocity is indicative of the overall morphology of the circumstellar material, implying that kinematic information is an important ingredient in modeling the snapshot monitoring (often in the optical and near-infrared) or the spectral imaging observations for molecular line emissions.

• Journal of Korean Dental Science
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• 제17권1호
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• pp.1-13
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• 2024

With the advances of digital scanning technology in dentistry, the interests in facial scanning in orthodontics have increased. There are many different manufacturers of facial scanners marketing to the dental practice. How do you know which one will work best for you? What questions should you be asking? We suggest a clinical guideline which may help you make an informed decision when choosing facial scanners. The characteristics of 7 facial scanners were discussed in this article. Here are some considerations for choosing a facial scanner. *Accuracy: For facial scanners to be of real value, having an appropriate camera resolution is necessary to achieve more accurate facial image representation. For orthodontic application, the scanner must create an accurate representation of an entire face. *Ease of Use: Scanner-related issues that impact their ease of use include type of light; scan type; scan time; file type generated by the scanner; unit size and foot print; and acceptance of scans by third-party providers. *Cost: Most of the expenses associated with facial scanning involve the fixed cost of purchase and maintenance. Other expenses include technical support, warranty costs, transmission fees, and supply costs. This article suggests a clinical guideline to make the right choice for facial scanner in orthodontics.

• 한국임상수의학회지
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• 제41권2호
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• pp.139-142
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• 2024

A wild Whooper swan (Cygnus Cygnus) with limping due to an injured left pelvic limb in an accident was rescued on the seashore and transferred to the Jeju Wildlife Rescue Center on November 23rd, 2020. On physical examination, its body condition score was 1 out of 5 due to starvation and dehydration. The left coxofemoral joint was also examined by careful palpating and estimating the damage. Moderated soft tissue swelling and crepitus surrounding the hip joint were confirmed. Radiography and computed tomography (CT) were used together for an accurate diagnosis of the joint. By radiographs readings, it was difficult to accurately confirm the condition of the proximal femur due to superimposition of the synsacrum and internal organs. However, signs such as avulsion fracture of the femoral head and a few fragments around the joint were revealed by CT imaging. Besides, through three-dimensional (3D) image analysis of CT, the dislocated area and condition of the left hip joint could be accurately and easily confirmed. The diagnostic process showing in this paper could be used as a good reference for diagnosing coxofemoral joint luxation in wild swan.

• Journal of Acupuncture Research
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• 제29권2호
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• pp.43-57
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• 2012

Objectives : The purpose of this study is to observe the effects of $Sa-Am$ lung sedating acupuncture (LS) on wrist pulse changes in healthy participants. Method : Forty healthy subjects participated in this study, and were divided into an acupuncture group and controlled group. Using a three-dimensional pulse imaging system (DMP-3000), wrist pulse was measured before, immediately after, 30 minutes after and 60 minutes after acupuncture in the acupuncture group, with the rest in controlled group. Sixteen parameters between the acupuncture group and the controlled group were analyzed at Cun, Guan and Chi in each time. Result : After LS acupuncture, wrist pulse sixteen parameters were changed significantly according to the time at each measuring region. 1. Heart rate significantly decreased in immediately after, 30 minutes after and 60 minutes after, Pulse period significantly increased in 30 minutes after and 60 minutes after. 2. T4 didn't significantly changed, T-T4 significantly increased in immediately after, 30 minutes after and 60 minutes after. T4/T, T4/(T-T4), T1/T, T5/T significantly decreased in immediately after, 30 minutes after and 60 minutes after. (T-T4)/T significantly decreased in immediately after, 30 minutes after and 60 minutes after. T5 significantly increased in 30 minutes after and 60 minutes after. 3. Modulus of elasticity significantly decreased in left Cun 60 minutes after, significantly increased in left Chi 30 minutes after. 4. Variance of Amplitude significantly increased in right Guan 60 minutes after. 5. Area of pulse significantly increased in left Cun 60 minutes after, left Chi 30 minutes after and right Cun 60 minutes after. Systolic pulse area significantly decreased left Chi 30 minutes after, right Cun immediately after, 30 minutes after and 60 minutes after, right Guan in immediately after. 6. Energy/min significantly decreased in left Chi 60 minutes after and right Cun immediately after. EIx significantly decreased in right Cun immediately after. 7. In both sides Cun, Guan, Chi wrist pulse, a lot of significant changes in right Cun and left Chi appeared, and then followed by the left Cun, right Guan. Conclusion : This study analyzed that the correlation between LS acupuncture and radial pulse(cun, guan, chi) is considered to be meaningful, hereafter clinical studies on this are needed.

• 대한치과교정학회지
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• 제38권5호
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• pp.314-327
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• 2008

본 연구는 하악골 3차원 입체영상에서 비대칭계측항목들의 재현도 비교를 통하여 안면비대칭 진단 시 유용한 계측점 설정에 도움이 되고자 시행되었다. 40명의 두경부 전산화단층사진을 이용하여 생성한 3차원 영상에서 하악골 형태를 결정짓는 부위로 하악과두, 하악우각부, 하악정중부를 선택하고 각 부위의 세부위치에 따라, 그리고 측정 시 보는 각도에 따라 구분하여 하악과두의 경우 $Cd_{sup}_{-}_{sup}$ 등 6개, 하악우각부의 경우 $Go_{inf}_{-}_{lat}$ 등 10개, 하악정중부의 경우 $Me_{-}_{ant},\;Me_{-}_{inf}$ 등 총 18개의 계측점을 설정한 후 이를 이용하여 하악골 비대칭 시 좌우 차이를 보일 수 있는 25개의 계측항목을 설정 및 계측한 후 조사자간 및 조사자내의 재현도를 비교 평가하였다. 조사자간 재현도의 경우 25개의 계측항목 중 3개를 제외한 모든 계측항목에서, 조사자내 재현도의 경우 2개 항목을 제외한 모든 계측항목에서 높은 재현도를 보였다. 아울러 본 연구에서 설정한 18개의 계측점 중 $Go_{mid}_{-}_{lat},\;Go_{mid}_{-}_{obl}$가 포함된 계측항목이 조사자간 및 조사자내 재현도가 떨어지는 경향을 보였다. 이상의 면구 결과 본 연구에서 사용된 18개의 계측점 중 16개의 계측점 (과두를 나타내는 $Cd_{sup}_{-}_{sup},\;Cd_{lat}_{-}_{ant},\;Cd_{lat}_{-}_{lat},\;Cd_{post}_{-}_{lat},\;Cd_{post}_{-}_{post},\;S$, 하악우각부를 나타내는 $Go_{int}_{-}_{lat},\;Go_{inf}_{-}_{inf},\;Go_{lat}_{-}_{ant},\;Go_{lat}_{-}_{lat},\;Go_{post}_{-}_{lat},\;Go_{post}_{-}_{post},\;Ag_{-}_{lat},\;Ag_{-}_{inf}$, 하악정중부를 나타내는 $Me_{-}_{ant},\;M_{-}_{inf}$)은 높은 재현도를 보이므로 전산화단층사진을 이용한 하악골 3차원 영상에서 안면비대칭 환자의 진단에 유용하게 사용될 수 있음을 시사하였다.

• Imaging Science in Dentistry
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• 제49권4호
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• pp.295-299
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• 2019

Purpose: This clinical pilot study was performed to determine the effectiveness of dual-energy cone-beam computed tomography (DE-CBCT) in measuring bone mineral density (BMD). Materials and Methods: The BMD values obtained using DE-CBCT were compared to those obtained using calibrated multislice computed tomography (MSCT). After BMD calibration with specially designed phantoms, both DE-CBCT and MSCT scanning were performed in 15 adult dental patients. Three-dimensional (3D) Digital Imaging and Communications in Medicine data were imported into a dental software program, and the defined regions of interest (ROIs) on the 3-dimensional surface-rendered images were identified. The automatically-measured BMD values of the ROIs (g/㎤), the differences in the measured BMD values of the matched ROIs obtained by DE-CBCT and MSCT 3D images, and the correlation between the BMD values obtained by the 2 devices were statistically analyzed. Results: The mean BMD values of the ROIs for the 15 patients as assessed using DE-CBCT and MSCT were 1.09±0.07 g/㎤ and 1.13±0.08 g/㎤, respectively. The mean of the differences between the BMD values of the matched ROIs as assessed using DE-CBCT and calibrated MSCT images was 0.04±0.02 g/㎤. The Pearson correlation coefficient between the BMD values of DE-CBCT and MSCT images was 0.982 (r=0.982, P<0.001). Conclusion: The newly developed DE-CBCT technique could be used to measure jaw BMD in dentistry and may soon replace MSCT, which is expensive and requires special facilities.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3037-3040
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• 2013

Introduction: Mammography is the most basic modality in breast cancer imaging. However, the overlap of breast tissue depicted on conventional two-dimensional mammography (2DMMG) may create significant obstacles to detecting abnormalities, especially in dense or heterogeneously dense breasts. In three-dimensional digital breast tomosynthesis (3DBT), tomographic images of the breast are reconstructed from multiple projections acquired at different angles. It has reported that this technology allows the generation of 3D data, therefore overcoming the limitations of conventional 2DMMG for Western women. We assessed the detectability of lesions by conventional 2DMMG and 3DBT in diagnosis of breast cancer for Japanese women. Methods: The subjects were 195 breasts of 99 patients (median age of 48 years, range 34~82 years) that had been pathologically diagnosed with breast cancer from December 20, 2010 through March 31, 2011. Both conventional 2DMMG and 3DBT imaging were performed for all patients. Detectability of lesions was assessed based on differences in category class. Results: Of the affected breasts, 77 (75.5%) had lesions assigned to the same categories by 2DMMG and 3DBT. For 24 (23.5%) lesions, the category increased in 3DBT indicating improvement in diagnostic performance compared to 2DMMG. 3DBT improved diagnostic sensitivity for patients with mass, focal asymmetric density (FAD), and architectural distortion. However, 3DBT was not statistically superior in diagnosis of the presence or absence of calcification. Conclusions: In this study, 3DBT was superior in diagnosing lesions in form of mass, FAD, and/or architectural distortion. 3DBT is a novel technique that may provide a breakthrough in solving the difficulties of diagnosis caused by parenchyma overlap for Japanese women.