• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.327-336
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• 1999

Purpose: To assess the quantitative accuracy and the clinical utility of 3D volumetric PET imaging with FDG in brain studies, 24 patients with various neurological disorders were studied. Materials and Methods: Each patient was injected with 370 MBq of 2-[$^{18}F$]fluoro-2-deoxy-D-glucose. After a 30 min uptake period, the patients were imaged for 30 min in 2 dimensional acquisition (2D) and subsequently for 10 min in 3 dimensional acquisition imaging (3D) using a GE $Advance^{TM}$ PET system, The scatter corrected 3D (3D SC) and non scatter-corrected 3D images were compared with 2D images by applying ROIs on gray and white matter, lesion and contralateral normal areas. Measured and calculated attenuation correction methods for emission images were compared to get the maximum advantage of high sensitivity of 3D acquisition. Results: When normalized to the contrast of 2D images, the contrasts of gray to white matter were $0.75{\pm}0.13$ (3D) and $0.95{\pm}0.12$ (3D SC). The contrasts of normal area to lesion were $0.83{\pm}0.05$ (3D) and $0.96{\pm}0.05$ (3D SC). Three nuclear medicine physicians judged 3D SC images to be superior to the 2D with regards to resolution and noise. Regional counts of calculated attenuation correction was not significantly different to that of measured attenuation correction. Conclusion: 3D PET images with the scatter correction in FDG brain studies provide quantitatively and qualitatively similar images to 2D and can be utilized in a routine clinical setting to reduce scanning time and patient motion artifacts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.55-64
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• 2006

In this paper, a new web-based remote 3D imaging communication system employing an adaptive matching algorithm is suggested. In the proposed method, feature values are extracted from the stereo image pair through estimation of the disparity and similarities between each pixel of the stereo image. And then, the matching window size for disparity estimation is adaptively selected depending on the magnitude of this feature value. Finally, the detected disparity map and the left image is transmitted into the client region through the network channel. And then, in the client region, right image is reconstructed and intermediate views be synthesized by a linear combination of the left and right images using interpolation in real-time. From some experiments on web based-transmission in real-time and synthesis of the intermediate views by using two kinds of stereo images of 'Joo' & 'Hoon' captured by real camera, it is analyzed that PSNRs of the intermediate views reconstructed by using the proposed transmission scheme are highly measured by 30dB for 'Joo', 27dB for 'Hoon' and the delay time required to obtain the intermediate image of 4 view is also kept to be very fast value of 67.2ms on average, respectively.

• Journal of Trauma and Injury
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• v.19 no.1
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• pp.28-34
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• 2006

Purpose: In maxillofacial surgery, proper preoperative diagnosis is very important in achieving good postoperative results. Although conventional CT scans are useful for visual representations of fractures, they cannot provide direct guidance for reconstructing facial bone fractures. However, the recent technology of multislice scanning has brought many clinical benefits to CT images. Direct correlations can be made between preoperative imaging data and operative planning. The aim of the current study is to evaluate the differences between conventional CT and multidetective three-dimensional CT(3D MDCT) measurements in craniofacial deformities. Methods: From January 2005 to November 2005, MDCT scans of 41 patients were evaluated by comparing them with conventional CT scans. The 3D MDCT images were assessed and reviewed by using a simple scoring system. Results: The 3D MDCT scans offered easy interpretation, facilitated surgical planning, and clarified postoperative results in malar complex fractures, mandibular fractures, and extensive maxillofacial fractures and cranioplasty. However, 3D MDCT images were not superior to conventional CT scans in the diagnosis of blowout fractures. Conclusion: In spite of its limitations, the 3D MDCT provided additional and more comprehensive information than the conventional CT for preoperative assessment of craniofacial deformities. Therefore, the 3D MDCT can be a useful tool for diagnosis and systematic treatment planning in craniofacial skeletal deformities.

• Korean Journal of Optics and Photonics
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• v.18 no.4
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• pp.246-255
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• 2007

The floating image system (FIS) is a device to display input source in the space between fast surface of the display and an observer and it provides pseudo 3D depth to an observer when input source as real object or 2D image was displayed through the optical lens system in the FIS. The Advanced floating image system (AFIS) was designed to give more effective 3D depth than existing FIS by adding front and rear depth cues to the displayed stereogram, which it was used as input source. The magnitude of disparity and size of stereogram were strongly related each other and they have been optimized for presenting 3D depths in a non-optical lens systems. Thus, if they were used in optical lens system, they will have reduced or magnified parameters, leading to problem such as providing incorrect 3D depth cues to an observer. Although the size of stereogram and disparity were demagnified by total magnifying power of optical system, the viewing distance (VD) from the display to an observer and base distance (BD) for the gap between the eyes were fixed. For this reason, the quantity of disparity in displayed stereogram through the existing FIS has not kept the magnifying power to the total optical system. Therefore, we proposed the methods to provide correct 3D depth to an observer by compensating quantity of disparity in stereogram which was satisfied to keep total magnifying power of optical lenses system by AFIS. Consequently, the AFIS provides a good floating depth (pseudo 3D) with correct front and rear 3D depth cues to an observer.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.9-14
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• 2010

Using an IR (infrared) optical system of observation and research were performed long before. Nowadays satellites equipped with IR optical system observe the earth and universe. In this paper, we developed the IR optical system for main payload of the STSAT-3 (Science and Technology Satellite -3). We studied the ultra precision machining technique to fabricate FPL-53 lenses which is the IR optical material for space observation camera of the STSAT-3. DOE (Design of Experiment) was used to find best machining characteristic for FPL-53. Finally we fabricated FPL-53 aspheric lens with the form accuracy of P-V $0.36\;{\mu}m$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.486-492
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• 2015

Radiation source imaging system is essential for protecting of radiation leakage accidents and minimizing damages from the radioactive materials, and is expected to play an important role in the nuclear plant decommissioning area. In this study, the stereoscopic camera principle was applied to develop a new radiation imaging device technology that can extract the radiation three-dimensional position information. This radiation three-dimensional imaging device (K3-RIS) was designed as a compact structure consisting of a radiation sensor, a CCD camera, and a pan-tilt only. It features the acquisition of stereoscopic radiation images by position change control, high-resolution detection by continuous scan mode control, and stereoscopic image signal processing. The performance analysis test of K3-RIS was conducted for a gamma-ray source(Cs-137) in radiation calibration facility. The test result showed that a performance error with less than 3% regardless of distances of the objects.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.4
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• pp.40-50
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• 2019

In recent years, it is important to visualize an accurate human body model for the low-end system in the medical imaging field where augmented reality technology and virtual reality technology are used. Decreasing the geometry of a model causes a difference from the original shape and considers the difference as an error. So, the error should be minimized while reducing geometry. In this study, the organ areas of a human body in the tomographic images such as CT or MRI is segmented and 3D geometric model is generated, thereby implementing the reconstruction method of multiple resolution level-of-detail model. In the experiment, a virtual reality platform was constructed to verify the shape of the reconstructed model, targeting the spine area. The 3D human body model and patient information can be verified using the virtual reality platform.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.101-107
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• 2016

Due to the recent advancement in digital imaging technology, development of intervention equipment has become generalize. Video arbitration procedure is a process to insert a tiny catheter and a guide wire in the body, so in order to enhance the effectiveness and safety of this treatment, the high-quality of x-ray of image should be used. However, the increasing of radiation has become the problem. Therefore, the studies to improve the performance of x-ray detectors are being actively processed. Moreover, this intervention is based on the reference of the angiographic imaging and 3D medical image processing. In this paper, we propose a guidance system to support this intervention. Through this intervention, it can solve the problem of the existing 2D medical images based vessel that has a formation of cerebrovascular disease, and guide the real-time tracking and optimal route to the target lesion by intervention catheter and guide wire tool. As a result, the system was completely composed for medical image acquisition unit and image processing unit as well as a display device. The experimental environment, guide services which are provided by the proposed system Brain Phantom (complete intracranial model with aneurysms, ref H+N-S-A-010) was taken with x-ray and testing. To generate a reference image based on the Laplacian algorithm for the image processing which derived from the cerebral blood vessel model was applied to DICOM by Volume ray casting technique. $A^*$ algorithm was used to provide the catheter with a guide wire tracking path. Finally, the result does show the location of the catheter and guide wire providing in the proposed system especially, it is expected to provide a useful guide for future intervention service.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.55-56
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• 1998

The 3-D Fast Gradient Echo (Turbo FLASH, Turbo Fast Low Angle Shot) sequence is optimized to achieve a good T1 contrast using variable excitation flip angles. In Turbo FLASH sequence, depending on the contrast preparation scheme, various types of image contrast can be established. While proton density contrast is obtained when using a short repetition time with a short echo time and small flip angles, T1 or T2 weighting can be obtained with proper contrast preparation sequences applied before the above proton density Turbo FLASH sequence. To maximize the contrast to noise ratio while retaining a sharp impulse response (smooth frequency domain response), the excitation flip-angle pattern is optimized through simulation and experiments. The TI (the delay after the preparation sequence which is a 180 degree inversion RF pulse in the IR T1 weighted imaging case), TD (the delay time between the Turbo FLASH sequence and the next preparation), and TR are also optimized fur the best image quality. The proposed 3-D Turbo FLASH provides $1mm\times1mm\times1.5mm$ high resolution images within a reasonable 5-8 minutes of imaging time. The proposed imaging sequence has been implemented in a Medison's Magnum 1.0T system and verified through simulations as well as human volunteer imaging. The experimental results show the utility of the proposed method.

• Journal of Powder Materials
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• v.24 no.3
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• pp.216-222
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• 2017

Synthesized monocrystalline nanodiamond (nD) particles are heat-treated at various temperatures to produce highly structured diamond crystals. The heat-treated nDs show different weight loss ratios during thermogravimetric analysis. The crystallinities of the heat-treated nDs are analyzed using Raman spectroscopy. The average particle sizes of the heat-treated nDs are measured by a dynamic light scattering (DLS) system and direct imaging observation methods. Moreover, individual dispersion behaviors of the heat-treated nD particles are investigated based on ultrasonic dispersion methods. The average particle sizes of the dispersed nDs according to the two different measurement methods show very similar size distributions. Thus, it is possible to produce highly crystallized nD powder particles by a heat-treatment process, and the nD particles are relatively easy to disperse individually without any dispersant. The heat-treated nDs can lead to potential applications such as in nanocomposites, quantum dots, and biomedical materials.