• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1359-1365
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• 2006

Digital Koguryo is a virtual reality reconstruction of the Koguryo mural tumulus, Anak No. 3, designed for an interactive educational gaming and learning environment. Digital Koguryo aims at not only developing a digital reconstruction of cultural heritage but also helping young students learn the living style and the custom of Koguryo Kingdom while playing the game environment. This paper describes the digital restoration process of Koguryo mural paintings and 3D structure, as well as the construction of educational virtual environment designed to get more user's interests. It then discusses a few design issues learned from the development and the public demonstration. Finally, it will present the future research directions to improve the users' immersion.

• The Journal of the Korean dental association
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• v.56 no.7
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• pp.366-374
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• 2018

Purpose : The purpose of this study was to compare the marginal fit of monolithic zirconia restorations fabricated form the conventional and the digital impression technique. Materials and methods : Ten patients were restored with monolithic zirconia restorations fabricated from the digital and the conventional impression technique. Before definitive insertion, silicone replicas were produced from all twenty crowns. The silicone replicas were cut in three sections; each section was evaluated at two points. The measurement was carried out by using a measuring microscope (Olympus BX 51) and I-Solution. Data from the silicone replica scores were analyzed by Shapiro-Wilk test for normal distribution and the t-test for equality of two population's mean. All tests were performed with ${\alpha}-level$ of 0.05. Results : The average marginal gaps of monolithic zirconia restorations were $133.81{\pm}36.46{\mu}m$ for the conventional impression technique, $90.07{\pm}9.47{\mu}m$ for the digital impression technique. No statistical differences were found between the two impression techniques Conclusion : Both prostheses presented clinically acceptable results with comparing the marginal fit.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.385-391
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• 2020

Soil loss is a serious problem frequently caused by local torrential rainfalls due to climate change. In particular, soil loss is occurring in agricultural areas rather than urban areas, and many pollutants are introduced into rivers, causing environmental problems. To reduce soil loss, the Ministry of Environment has designated and managed non-point source management areas. The Jaun-district in Hongcheon-gun, which was designed as a non-point pollution source management area in Gangwon-do, is located in the upper stream of Soyang Lake. Most of the agricultural fields are composed of highland agriculture fields. The highland agricultural fields in the Jaun-district are also composed of large-scale farming areas, and the ditches located near the agricultural fields have been illegally used for farmland. Therefore, the local government in Hongcheon-gun is conducting a project to restore the ditches occupied by agricultural fields. However, an analysis of the amount of soil loss that can be reduced by the restoration of the ditches has not been conducted yet. Thus, the purpose of this study was to analyze the effect of reducing the soil loss from the restoration of the ditches used as agricultural fields in the Jaun-district. The SATEEC L Module was used to analyze the reduction in soil loss by ditch restoration. The SATEEC L Module was constructed to estimate the LS factor using Moore and Burch's method after calculating the slope length using the digital elevation model and the maximum allowable slope length. The LS factor and the USLE formula were used to estimate the amount of soil loss that could be reduced by ditch restoration. The analysis showed that the ditch restoration could reduce about 16.6% of the soil loss in the Jaun-district. The results of this study will contribute to the study of methods to reduce soil loss in non-point pollution management areas.

• The KIPS Transactions:PartB
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• v.13B no.4 s.107
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• pp.369-376
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• 2006

The degradation and its inverse modeling can achieve restoration of corrupted image, caused by scaled digitization and electronic transmission. De-speckle process on the noisy document(or SAR) images is one of the basic examples. Non-linearity of the speckle noise model may hinder the inverse process. In this paper, our study is focused on investigation of the restoration methods for bi-level document image degraded by the impulse noise model. Our study shows that, on bi-level document images, the weighted-median filter and the Lee filter methods are very effective among other spatial filtering methods, but wavelet filter method is ineffective in aspect of processing speed: approximately 100 times slower. Optimal values of the weight to be used in the weighted median filter are investigated and presented in this paper.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.57-62
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• 1999

Estimation of the point spread function (PSF) is one of the main research topic of image processing, because it determines the performance of the auto-focusing system. In this paper, a new algorithm for PSF estimation is proposed, and its application to image restoration is also presented. The procedure for complete realization of the auto-focusing system consists of two steps: PSF estimation based on edge classification, and image restoration using the estimated PSF. More specifically, we divide imput image into multiple small image or block, estimate unit step response and average them on the blocks which contain edge, and estimate 2-dimensional isotropic PSF from the 1 dimensional step response. Finally we obtain in-focused image by using image restoration based on the estimated PSF.

• The KIPS Transactions:PartD
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• v.15D no.4
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• pp.581-588
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• 2008

Old films or photographs usually have damages from physical or chemical effects, and the damage and digitalization make stain, scratch, scribbling, noise, and digital drop out in frames. Damages include global damage and local damage, and it is well known that local damage restoration is a main factor for improving image quality. Previous researches have focused on impairment localization (esp. for line scratch impairments) and restoration techniques for line scratch, dirt, blob, and intentional scratch. Inpainting is a key technique using partial derivatives to restore damages in images. It does not show good quality for the complex images because it is based on finite order for partial derivatives, and it takes much time complexity. In this paper, we present a modified inpainting scheme, where we use Sobel edge operator's and angle to compute isophotes, and compare our scheme with Bertalmio's scheme. We experiment our scheme with two old Korean films, and Simulation results show that our scheme requires smaller time complexity than Bertalmio's scheme with comparable reconstructed image quality.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.78-87
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• 2008

Digital image find own level core media in multimedia as image restoration technology fields, which remove degradation factor for image enhancement, have been growing. Linear space-invariant image restoration algorithm often introduce ringing artifacts near sharp intensity transition areas. This paper presents a new adaptive post-filtering algorithm for reducing ringing artifact. The proposed method extracts an edge map of the image using wavelet transform Based on the edge information, ringing artifacts are detected, and removed by an adaptive bilateral filter. Experimental results show that the proposed algorithm can efficiently remove ringing artifacts with edge preservation.

• The Journal of the Korea Contents Association
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• v.5 no.4
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• pp.133-140
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• 2005

Culture Technology is the basic technology which produces cultural contents in a narrow sense. All nations do their best in order to create new contents which can form international and cultural sympathy. If a variety of contents are created by applying Korean proper cultural heritages, they will be creative and competitive internationally. Therefore, technology of original cultural restoration is an essential and crucial skill. In this paper, 'gilt bronze dragon-phoenix ring-pommeled sword', a cultural heritage of baekje age, will be restored to the original form digitally on the basis of three-dimensional shape-information processing technology and the scientifically analyzed data. First of all, data from three-dimensional scanning is revised using stuffing and smoothing methods after sampling, extracting characteristics, and align. Then, they are modeled in a curved surface with NURBS and B-Spline. Secondly, textures are edited by estimating the color of components and the quality of materials, and then they are mapped. Original form model which was made was revised and corrected by specialists' examinations. The digitally revised ring-pommeled sword was combined with information technology, and it can be used to revise damaged cultural heritages by constructing formal database of ring-pommeled sword with regard to age, area and type. It can be also used as educational contents in archaeology or preservation science and cultural contents such as movies, broadcasts, games, animations and so on.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.210-217
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• 2016

Purpose: The aim of this study was to evaluate the marginal and internal adaptation of monolithic zirconia restoration made without physical model by digital intraoral scanner. Materials and methods: A prospective clinical trial was performed on 11 restorations as a pilot study. The monolithic zirconia restorations were fabricated after digital intraoral impression taking by intraoral scanner (TRIOS, 3shape, Copenhagen, Denmark), computer-aided designing, and milling manufacturing process. Completed zirconia crowns were tried in the patients' mouth and a replica technique was used to acquire the crown-abutment replica. The absolute marginal discrepancy, marginal gap, and internal gap of axial, line angle, and occlusal part were measured after sectioning the replica in the mesiodistal and buccolingual direction. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U test (${\alpha}=.05$). Results: From the adaptation analysis by replica, the statistically significant difference was not found between mesiodistal and buccolingual sections (P>.05), but there was significant difference among the measurement location (P<.01). The amount of absolute marginal discrepancy was larger than those of marginal gap and internal gap (P<.01). Conclusion: Within the limitations of this study, the adaptation accuracy of model-free monolithic zirconia restoration fabricated by intraoral scanner exhibited clinically acceptable result. However, the margin of zirconia crown showed tendency of overcontour and cautious clinical application and follow up is necessary.

• Journal of Convergence for Information Technology
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• v.11 no.1
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• pp.136-142
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• 2021

Open-pit mine development requires continuous management because of topographical changes and there is a risk of accidents if the current status survey is performed directly in the process of calculating the earthwork. In this study, the application of UAV photogrammetry, which can acquire spatial information without direct human access, was applied to open-pit mines development area and analyzed the accuracy, earthwork, and mountain restoration plan to determine its applicability. As a result of accuracy analysis at checkpoint using ortho image and Digital Surface Model(DSM) by UAV photogrammetry, Root Mean Square Error(RMSE) is 0.120 m in horizontal and 0.150 m in vertical coordinates. This satisfied the tolerance range of 1:1,000 digital map. As a result of the comparison of the earthwork, UAV photogrammetry yielded 11.7% more earthwork than the conventional survey method. It is because UAV photogrammetry shows more detailed topography. And result of monitoring mountain restoration showed possible to determine existence of rockfall prevention nets and vegetation. If the terrain changes are monitored by acquiring images periodically, the utility of UAV photogrammetry will be further useful to open-pit mine development.