• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.369-375
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• 2011

In dental radiography, panoramic views cause distortion and thus may bring about inaccurate results in the process of quantitative analysis. In this connection, there has recently been an increasing use of cone beam computed tomography (CBCT) that is known to provide high-resolution images and positional information. In this study, a dental computed tomography unit, 'DCT-90-P IMPLAGRAPHY (Vatech, Korea)', was applied to 20 patients for 24 seconds respectively, with a tube voltage of 85kVp and a tube current of 7mA. The data of CBCT were three-dimensionally reconstructed by use of a computer program, and were histomorphometrically analyzed. The results showed that the diameter of mandibular canal is less distorted at a certain inclination of the mandibular body. The image tends to seem more distended in proportion to the distance between the subject and film. Also, the image tends to be affected according as it is out of focus. In conclusion, it requires that the image should be reconstructed in light of anatomic position and structure.

• Journal of the Korea Computer Graphics Society
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• v.23 no.5
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• pp.9-17
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• 2017

Filming using multiple cameras is required for the production of the multi-screen content. It can fill the viewer's field of view (FOV) entirely to provide an increased sense of immersion. In such a filming scenario, it is very important to monitor how images captured by multiple cameras are displayed as a single content or how the content will be displayed in an actual theatre. Most recent studies on creating the content of special format have been focused on their own purposes, such as stereoscopic and panoramic images. There is no research on content creation optimized for theatres that use three screens that are spreading recently. In this paper, we propose a novel content production system with a rig that can control three cameras and monitoring software specialized for multi-screen content. The proposed rig can precisely control the angles between the cameras and capture wide angle of view with three cameras. It works with monitoring software via remote communication. The monitoring software automatically aligned the content in real time, and the alignment of the content is updated according to the angle of camera rig. Futher, the producion efficiency is greatly improved by making the alignment information available for post-production.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.3
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• pp.71-80
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• 2019

The Fourth Industrial Revolution, centered on intelligence and information, began to take hold in 2016. This study uses virtual reality technology, which is the most popular technology of the Fourth Industrial Revolution. The purpose of this study is to explore a Virtual Walk-through method, which can be easily applied to landscape architecture. At present, virtual reality technology is widely used in the fields of games, emergency training, and architectural design. However, in the field of landscape architecture, it is still in the development stage. In addition, most of the traditional ways to display virtual reality use 2D images, but such methods have some limitations. Therefore, this research addresses the three stages of "design-exhibition-experience" and puts forward a new simple method called 'Virtual Walk-through' that breaks from traditional landscape design exhibitions. The results show that compared with traditional methods, virtual reality has many advantages, such as the freedom of experience, a diversity of viewing angles, information supply, interaction, etc. It can show high quality images and effects, which are suitable for landscape design. It provides an evaluation method for garden design that can be utilized in the future. It is simple and has value as it can reflect the method and the expected effects. Virtual reality technology can bring an infinite number of prospects to the development of landscape architecture.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.4
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• pp.196-203
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• 2022

Purpose: This study aimed to evaluate the accuracy and clinical usability of an identification model using deep learning for 79 dental implant types. Materials and Methods: A total of 45396 implant fixture images were collected through panoramic radiographs of patients who received implant treatment from 2001 to 2020 at 30 dental clinics. The collected implant images were 79 types from 18 manufacturers. EfficientNet and Meta Pseudo Labels algorithms were used. For EfficientNet, EfficientNet-B0 and EfficientNet-B4 were used as submodels. For Meta Pseudo Labels, two models were applied according to the widen factor. Top 1 accuracy was measured for EfficientNet and top 1 and top 5 accuracy for Meta Pseudo Labels were measured. Results: EfficientNet-B0 and EfficientNet-B4 showed top 1 accuracy of 89.4. Meta Pseudo Labels 1 showed top 1 accuracy of 87.96, and Meta pseudo labels 2 with increased widen factor showed 88.35. In Top5 Accuracy, the score of Meta Pseudo Labels 1 was 97.90, which was 0.11% higher than 97.79 of Meta Pseudo Labels 2. Conclusion: All four deep learning algorithms used for implant identification in this study showed close to 90% accuracy. In order to increase the clinical applicability of deep learning for implant identification, it will be necessary to collect a wider amount of data and develop a fine-tuned algorithm for implant identification.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.379-388
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• 2002

For the success of dental implant, accurate radiographic evaluation is prerequisite for planning the location of the osseointegrated implants and avoiding injury to vital structures. CT/MPR(computed tomography/multiplanar reformation) shows improved visualization of inferior alveolar canal. In order to obtain cross-sectional images parallel to the teeth, the occlusal plane is used to orientate for the axial plane. If the direction of axial plane is not parallel to the occlusal plane, the reformatted cross-sectional scans will be oblique to the planned fixture direction and will not show the actual dimension of the planned fixture's location. If the available bone height which measured in the cross-sectional view is much greater than the actual available bone height, penetration of canal may occur. The aim of this study is to assess the effect of the axial plane to measurement of available bone height for dental implant in computed tomography of the mandible. 40 patients who had made radiographic stents and had taken CT were selected. The sites that were included in the study were 45 molar regions. In the central panoramic scan, the length from alveolar crest to superior border of inferior alveolar canal(available bone height, ABH) was measured in direction of reformatted cross-sectional plane(uncorrected ABH). Then, length from alveolar crest to superior border of canal was measured in direction of stent(corrected ABH). The angle between uncorrected ABH and corrected ABH was measured. From each ABH, available fixture length was decided by $Br{{\aa}}nemark$ system. The results were following ; the difference between two ABHs was statistically significant in both first and second molar(p< 0.01). The percentage of difference more than 1 mm was 8.7% in first molar and 15.5% in second molar. The percentage of difference more than 2 mm was 2.0% in first molar and 6.6% in second molar. The maximum value of difference was 2.5 mm in first molar and 2.2 mm in second molar. The correlations between difference of 2 ABHs and angle was positive correlations in both first and second molar. The correlation coefficient was 0.534 in first molar and 0.728 in second molar. The second molar has a stronger positive correlation. The percentage of disagreement between 2 fixture lengths from two ABHs was 24.4% in first molar and 28.9% in second molar.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.3
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• pp.317-326
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• 2011

The mental foramen and anterior loop of the mandibular canal are important landmarks for mandibular surgical procedures. The purpose of this study was to analyze the shape and position of the mental foramen and anterior loop of the mandibular canal on the computed tomography (CT) images, and apply the results clinically. CT images of 96 patients (33 male, 36 female, age range 17~43 years, mean $24.6{\pm}4.99$ years) were enrolled. The horizontal and vertical position of the mental foramen, as well as the distance from the root apices were measured. The distance of the anterior loop of the mandibular canal to the root apices, and the buccal angle were measured. The mental foramen was found mostly below the second premolar observed in 81 cases (46.0%), between the first and second premolars in 67 cases (38.0%), and between the second premolar and first molar in 19 cases (10.2%). The mean distance between the mental foramen and the lower border of the mandible was $12.20{\pm}1.77$ mm, the mean distance between the mental foramen and root apex was $5.16{\pm}0.98$ mm. The mean distance of the anterior loop of the mandibular canal was $5.80{\pm}2.00$ mm. The buccal angle measured at $47.7{\pm}9.07^{\circ}$. The distance between the root apex and mental foramen measured as $5.16{\pm}0.98$ mm on panoramic radiography, and $6.2{\pm}3.07$ mm on CT. The mean distance between the mental foramen and mandibular canal was $5.39{\pm}1.62$ mm. When performing surgical procedures such as installing dental implants, it is important to minimize surgical trauma, especially the risk of damage to the mental nerve. To optimize the surgical outcome, a careful assessment of the shape and position of the mental foramen and the anterior loop of the mandibular canal must be made. CT images are useful for finding such anatomic structures.

• Journal of the Korea Computer Graphics Society
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• v.26 no.3
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• pp.133-142
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• 2020

In this research, we describe the method of implementing a 360-degree panorama using one projector, in terms of hardware and in the production of projected pre-distortion images. We propose a method of installing a projector and a reflector on the central ceiling of the space to minimize the shadows generated based on the position of the spectators. We used a virtual camera and virtual space where the projector and hemisphere positions were set to the same as in the exhibition space in Unity. After the image projected on the screen was mapped on the wall of the virtual space, the pre-distortion image was created by the method of capturing from the virtual camera using the ray tracing technique. When the produced pre-distortion image is hemispherical reflected and projected by the projector installed at the same position as the virtual camera, the image is reflected and projected 360 degrees on the panoramic screen.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.3
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• pp.281-290
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• 2021

Purpose. The aim of this study is to evaluate bone change around the implant in patients who underwent alveolar ridge preservation for implantation in the posterior teeth using radiographic data measuring changes of mesial, distal crestal bone level according to post-implantation, post-final prosthesis delivery and follow-up periods. Materials and methods. In total, 36 implants were placed in 32 patients. The mesial and distal crestal bone level of all the areas where alveolar ridge preservation was performed uses panoramic images taken post-implantation, post-final prosthesis delivery, and follow-up period each was measured and evaluated as a vertical value. The following factors were analyzed: associations between changes of crestal bone level and factors (e.g., age, sex, systemic diseases, dentist, implant location, tooth, bone type, membrane). The statistical analysis was performed using the mean, standard deviation and independent t-test, paired t-test (P < .05). Results. Analysis of crestal bone level differences between periods shows statistically significant differences (P < .05). There was no statistically significant difference when the changes of crestal bone level between post-implantation, post-final prosthesis delivery and follow-up periods were correlated with each factors. Conclusion. After alveolar ridge preservation, bone around the implant remained stable during the maintenance period without being affected by the patient and surgical factors, and alveolar ridge preservation is considered a clinically usable procedure.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.3
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• pp.61-77
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• 2011

This study focused on relevant rock names related to Sinsun(神仙) which had been settled as Taoist traces were combined with places. While interpreting major features of Sundoism relevant rocks, it also discussed types and places of rocks reflected in their names by considering distinct characteristics of landscape characters that ancestors viewed through the rocks or on the rocks. Conclusion of this study is summarized as follows. 1. Among the rock names related to Sinsun, the most frequently discovered one was Sinsunbawi(52) and followed by Sinsunbong(神仙峰: 38), Sinsundae(神仙臺: 31). Other than these, there were Gangsundae(降仙臺: 12), Sunyoodae (仙遊臺: 10) and Sasundae(四仙臺: 5). 2. In the name of Sinsundae, 'Dae(臺)' ascertains that it was located in greatly superb place in the aspects of viewpoint and appreciation where landscape superiority and overlook scenery were fair and outstanding. 3. Sinsunbong was named for a peak of mountain. At the same time, it implied a notion of worship with images of 'merging with sky' or 'looking up.' Most of time, Sinsunbong indicated the tallest rock in the mountain chain. 4. A significant number of Sinsunbong had names where legends of Sinsun's Go game or descent were originated from. It shows that 'Sinsun(仙) and Go game' used to be very important motives for folk etymology of Sinsun related rocks. Along with the Sinsundae, a number of Sinsunbawi were also turned out to exist in land and ocean with excellent marine view. 5. According to analysis of their altitudes and heights of the peaks where the rocks belong to, Sinsunbong, Sinsundae and Sinsunbawi were in order. It might indicate that the rocks were located on top of mountain or that Sinsunbong represented the mountain itself. Compared to this, Sinsundae was located in where distant panoramic views were overlooked. It was not necessarily to be in peak but in where with a great view like Taoist world. On the other hand, Sinsunbawi was located in where has fine scenery and great valley not so far from villages, which proved its name had been influenced by place feature not altitude. 6. Feature of rock with Sinsun related name is to comprise visual stability of worship object with close linkage to attitude of worshiper. Considering its deep connection with communicative method of worship object and worshiper, seemingly it was main factor to lead folk etymology of rocks with Sinsun related names. 7. Rock is an object with the greatest implication of Sinsun imagination and Sinsun rocks show most clearly the fact that Taoism, which used to be considered as inaccessible, had been actualized in a visual and realistic manner with the change of time.