• Journal of the HCI Society of Korea
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• v.8 no.2
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• pp.21-27
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• 2013

Recently, the use of floating hologram has increased in many different aspects, such as exhibitions, education, advertisements, and so on. Especially, the floating hologram that makes use of half-mirror is widely used. Nevertheless, half-mirror, unfortunately, cannot lead users to the perfect three dimensional hologram experience. Even though it can make the vision look to be up on the air, it does not have the capacity to display itself up on the air, which is the ultimate goal of hologram. In addition, it looks inconsistent when a real object is located behind the half-mirror in order to show the convergence of the two (object and the half-mirror). In this paper, we did the study on comparison of 3D space perception for the stereoscopic AR holography. At first, we applied stereoscopic technology to the half-mirror hologram system for the accurate and realistic AR environment. Then, the users can feel as if the real 3D object behind half-mirror and the reflected virtual image are converged much better in the 3D space. Furthermore, by using depth camera, the location and direction of graphics can be controlled to change depending on the user's point of view. This is the effective way to produce augmented stereoscopic images simply and accurately through half-mirror film without any additional devices. What we saw from the user test were applying 3D images and user interaction leads the users to have 3D spatial awareness and realism more effectively and accurately.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.35-41
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• 2006

Purpose: A various find of radiotherapy treatment plans have been made to determine appropriate doses for breasts, chest walls and loco-regional lymphatics in the radiotherapy of breast cancers. The aim of this study was to evaluate the optimum radiotherapy plan technique method by analyzing dose distributions qualitatively and quantitatively. Materials and Methods: To evaluate the optimum breast cancer radiotherapy plan technique, the traditional method(two dimensional method) and computed tomography image are adopted to get breast volume, and they are compared with the three-dimensional conformal radiography (3DCRT) and the intensity modulated radiotherapy (IMRT). For this, the regions of interest (ROI) such as breasts, chest walls, loco-regional lymphatics and lungs were marked on the humanoid phantom, and the computed tomography(Volume, Siemens, USA) was conducted. Using the computed tomography image obtained, radiotherapy treatment plans (XiO 5.2.1, FOCUS, USA) were made and compared with the traditional methods by applying 3DCRT and IMRT. The comparison and analysis were made by analyzing and conducting radiation dose distribution and dose-volume histogram (DVH) based upon radiotherapy techniques (2D, 3DCRT, IMRT) and point doses for the regions of interest. Again, treatment efficiency was evaluated based upon time-labor. Results: It was found that the case of using 3DCRT plan techniques by getting breast volume is more useful than the traditional methods in terms of tumor delineation, beam direction and confirmation of field boundary. Conclusion: It was possible to present the optimum radiotherapy plan techniques through qualitative and quantitative analyses based upon radiotherapy plan techniques in case of breast cancer radiotherapy. However, further studies are required for the problems with patient setup reproducibility arising from the difficulties of planning target volume (PVT) and breast immobilization in case of three-dimensional radiotherapy planning.

• Journal of Digital Convergence
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• v.15 no.6
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• pp.369-376
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• 2017

In a digital multimedia environment with various experiences and communication, We live in an age where it is possible to experience from imagination to reality realizable by imagination. The remarkable technology based on ICT has been attracting attention as next generation video service technology from 3DTV, UHD TV, and hologram. These media, combined with space design, are able to offer us amazing and diverse experiences. In addition, now, there is a demand for more differentiated contents using human five senses recognition technology. We analyzed the application of realistic contents to space design. As a result, we have come to the conclusion that creative production which can express more fun and convenient will be an important issue.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.879-886
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• 2018

A 3-dimensional (D) printer is a device capable of outputting a three-dimensional solid object based on data modeled in a computer. These features are utilized in the bone model X - ray phantom production etc using CT data by fusing with the radiation science field. A bone model phantom was made using data obtained by CT scan of an existing Pelvis phantom, using PLA, Wood, XT-CF20, Glow fill, Steel filaments which are materials of Fused Filament Fabrication (FFF) 3D printer.Measure Hounsfield Unit (HU) with images obtained by CT scan of the existing Pelvis phantom and five material phantoms made with 3D printer under the same conditions,SI and SNR were measured using a diagnostic X-ray generator, and each phantom was compared and analyzed.As a result, the X - ray phantom in the X - ray examination condition of the limb was found to be most suitable for the glow fill filament.The characteristics of the filament can be known to the base of this research and the practicality of X - ray phantom fabrication was confirmed.

• Progress in Medical Physics
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• v.7 no.2
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• pp.67-77
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• 1996

Purpose: To get a 3-D coordinates of intracranial target position was investicated in axial, sagittal and coronal magnetic resonance imaging with a preliminary experimented target localizer. Material and methods : In preliminal experiments, the localizer is made of engineering plastic to avoid the distrubance of magnetic field during the MR image scan. The MR localizer displayed the 9 points in three different axial tomogram. The bright signal of localizer was obtjained from 0.1～0.3％ of paramagnetic gadolinium/DTPA solution in T1WI or T2WI. In this study, the 3-D position of virtual targets were examined from three different axial MR images and the streotactic position was compared to that of BRW stereotactic system in CT scan with same targets. Results: This study provided the actual target position could be obtained from single scan with MRI localizer which has inverse N-typed 9 bars. This experiment was accomplished with shimming test for detection of image distortion in MR image. However we have not found the image distortion in axial scan. The maximum error of target positions showed 1.0 mm in axial, 1.3 mm for sagittal and 1.7 mm for coronal image, respectivelly. The target localization in MR localizer was investicated with spherical virtual target in skull cadaver. Furthermore, the target position was confirmed with CRW stereotactic system showed a 1.3 mm in discrepancy. Summary : The intracranial target position was determined within 1.7 mm of discrepancy with designed MR localizer. We found the target position from axial image has more small discrepancy than that of sagittal and coronal image.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.107-113
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• 2000

Purpose : The goal of this study 닌as to improve the accuracy of three-dimensional conformal radiotherapy (3-D CRT) by measuring the treatment setup error and physiological movement of liver based on the analysis of images which were obtained by electronic portal imaging device (EPID). Materials and Methods : For 10 patients with hepatocellular carcinoma, 4-7 portal images were obtained by using EPID during the radiotherapy from each patient daiiy. We analyzed the setup error and physiological movement of liver based on the verification data. We also determined the safety margin of the tumor in 3-D CRT through the analysis of physiological movement. Results : The setup errors were measured as 3mm with standard deviation 1.70 mm in x direction and 3.7 mm with standard deviation 1.88 mm in y direction respectively. Hence, deviation were smaller than 5mm from the center of each axis. The measured range of liver movement due to the physiological motion was 8.63 mm on the average. Considering the motion of liver and setup error, the safety margin of tumor was at least 15 mm. Conclusion : EPID is a very useful device for the determination of the optimal margin of the tumor, and thus enhance the accuracy and stability of the 3-D CRT in patients with hepatocellular carcinoma.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.403-414
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• 2004

In the accompanying paper, we proposed a real. time volumetric imaging method using a cross array based on receive dynamic focusing and synthetic aperture focusing along lateral and elevational directions, respetively. But synthetic aperture methods using spherical waves are subject to beam spreading with increasing depth due to the wave diffraction phenomenon. Moreover, since the proposed method uses only one element for each transmission, it has a limited transmit power. To overcome these limitations, we propose a new real. time volumetric imaging method using cross arrays based on synthetic aperture technique with linear wave fronts. In the proposed method, linear wave fronts having different angles on the horizontal plane is transmitted successively from all transmit array elements. On receive, by employing the conventional dynamic focusing and synthetic aperture methods along lateral and elevational directions, respectively, ultrasound waves can be focused effectively at all imaging points. Mathematical analysis and computer simulation results show that the proposed method can provide uniform elevational resolution over a large depth of field. Especially, since the new method can construct a volume image with a limited number of transmit receive events using a full transmit aperture, it is suitable for real-time 3D imaging with high transmit power and volume rate.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.25-35
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• 2020

Recently, the development of image processing technology, as well as hardware performance, has been continuing the research on 3D point processing technology that provides users with free viewing angle and stereoscopic effect in various fields. Point cloud technology, which is a type of representation of 3D point, has attracted attention in various fields because it can acquired/expressed point precisely. However, since Hundreds of thousands, millions of point are required to represent one 3D point cloud content, there is a disadvantage that a larger amount of storage space is required than a conventional 2D content. For this reason, the MPEG (Moving Picture Experts Group), an international standardization organization, is continuing to research how to efficiently compress, store, and transmit 3D point cloud content to users. In this paper, a V-PCC bitstream generated by a V-PCC (Video-based Point Cloud Compression) encoder proposed by the MPEG-I (Immersive) group is composed of an MPU (Media Processing Unit) defined by the MMT. In addition, by extending the signaling message defined in the MMT standard, a parameter for a segmented transmission method of the 3D point cloud content by area and quality parameters considering the characteristic of the 3D point cloud content, so that the quality parameters can be selectively determined according to the user's request. Finally, in this paper, we verify the result through design/implementation of the verification platform based on the proposed technology.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.4
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• pp.311-316
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• 2008

In this study, we have investigated the effects of ultraviolet (UV) irradiation on the external and internal structure of human hair. For changes in morphological and chemical structure of UV-exposed hair, we utilized several microscopic techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), confocal laser scanning microscope (CLSM), and etc. The SEM showed the scales of UV-exposed hair appeared to be rough and bulkier because of chemical oxidation during UV irradiation. Small bulgy area of UV_exposed hair surface was appeared as a result of the decomposition in cysteic acid. In the TEM picture the UV-exposed hair showed the cleaved aperture of hair and destruction of melanin granules. Three dimensional topographical images were obtained by using CLSM. In the optical single section, high fluorescent intensity appeared in virgin hair. In the case of UV-exposed hair, low fluorescence intensity appeared. This means the aromatic amino acids in virgin hair were more abundant than UV-exposed hair.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.3
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• pp.237-246
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• 2020

Recently, as high resolution satellites data have been serviced, frequent DSM (Digital Surface Model) generation over urban areas has been possible. In addition, it is possible to detect changes using a high-resolution DSM at building level such that various methods of building change detection using DSM have been studied. In order to detect building changes using DSM, we need to generate a DSM using a stereo satellite image. The change detection method using D-DSM (Differential DSM) uses the elevation difference between two DSMs of different dates. The D-DSM method has difficulty in applying a precise vertical threshold, because between the two DSMs may have elevation errors. In this study, we focus on the urban structure change detection using D-nDSM (Differential nDSM) based on nDSM (Normalized DSM) that expresses only the height of the structures or buildings without terrain elevation. In addition, we attempted to reduce noise using a morphological filtering. Also, in order to improve the roadside buildings extraction precision, we exploited the urban road network extraction from nDSM. Experiments were conducted for high-resolution stereo satellite images of two periods. The experimental results were compared for D-DSM, D-nDSM, and D-nDSM with road extraction methods. The D-DSM method showed the accuracy of about 30% to 55% depending on the vertical threshold and the D-nDSM approaches achieved 59% and 77.9% without and with the morphological filtering, respectively. Finally, the D-nDSM with the road extraction method showed 87.2% of change detection accuracy.