• Journal of radiological science and technology
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• v.14 no.1
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• pp.29-44
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• 1991

A Study on the distribution and types of the total 40 CT units, as of 1st October 1990, in Pusan area(29 for whole body CT units, 11 for brain CT units) were carried out during the period from January 1989 to December 1989 to find out the status of operation and utilization of whole body CT units. The results were as following ; 1. As of 1st October 1990 in Pusan area, a total of 40 CT units(29 for whole body CT units, 11 for brain CT units) were set up and operated. The number of cases of CT examination performed per day per unit were appeared to be less than 5 cases among 59.5% of CT units, and 2.7% of the total units has peformed more than 16 examinations. 2. The CT units under operation occupied 93.5% of the total and 2.6% of the total units was not properly been operated due to mechanical breakdown. This results is appeared to be better than other reports. 3. The average number of scanning per week for each CT were 35 cases and the average days under operation of the unit per week were 6.7 days. Consequently, the average days under operation of units was higher than that of the other reports, but the average number of scanning was lower. 4. The cases referred from other institutes to hospitals were 6.4% of total cases. 5. As a site of scanning, the brain appeared most frequently with 71.2% of the total cases and followed by spine 12.4%, abdomen 8.5%, and thorax 3.6%, respectively. 6. Positive rate by scanning was 70.8% of total cases, and it was 98.9% with thorax, abdomen 96.3%, spine 93.1%, and brain 38.4%, respectively. According to the results of this study, it is highly recommended that the regulations and the guidelines for setting-up of such high cost medical equipments as CT units be provided in order to ensure the cost-effectiveness of the system.

• Journal of Information Technology Services
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• v.11 no.sup
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• pp.103-111
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• 2012

In epigraph field to study ancient scripts, alternative readability improvement technologies have been developed to replace existing rubbing method which has low resolution and causes surface pollution of heritages from the viewpoints of extraction process and used materials. Recently many methods which are based on analysis of pixel data for extracting outlines of the specific image have been developed with advancement of image processing techniques. But these methods are not applicable and the results are not satisfied in the damaged inscriptions which are weathered by wind and rain for a long time and in the narrowed one. In this paper laser scanning techniques which uses optical triangulation measurement principle are developed to minimize scanning error. The proposed techniques are consisted of 3 parts：(1) the understanding of optical triangulation measurement principle to find scanning guideline (2) determinations of points interval, scanning distance and scanning angle to guarantee scanning data quality (3) identification of valid point data area which will be used in registration process. The proposed character identification method contributed in decoding an ancient inscription on SeukBingGo in Kyungju.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.171-179
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• 2004

Micro-stereolithography technology has made it possible to fabricate a freeform 3D microslructure. This technology is based on conventional stereolithography, in which a UV laser beam irradiates the open surface of a UV-curable liquid photopolymer, causing it to solidify. In micro-stereolithography, a laser beam of a few $\mu m$ diameter is used to solidify a very small area of the photopolymer. This is one of the key technological elements, and can be achieved by using a focusing lens. Thus, the solidification phenomena of the liquid photopolymer must be carefully investigated. In this study, the photopolymer solidification phenomena in response to variations in the scanning pitch of a focused laser beam was investigated experimentally. The effect of layer thickness on the solidification width and depth was also examined. These studies were conducted under the conditions of relatively lower laser power and relatively higher scanning speed. Moreover, the photopolymer solidification phenomena for the relatively higher laser power and lower scanning speed was investigated, too. In this case, comparing to the case of lower laser power and higher scanning speed, the photopolymer absorbed large amount of irradiation energy of the laser beam. These results were compared with those obtained from a photopolymer solidification model. From these results, a new laser-scanning scheme was proposed according to the shape of the 3D model. Samples by each method were fabricated successfully.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.943-946
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• 2004

We report the laser scanning display as an emerging technology. We show demonstration system of laser TV, Video image is made by using a high speed MEMS scanning mirror and a direct-modulated red diode laser. We designed and fabricated MEMS scanning mirror. The first demonstration system showed a NTSC-resolution video image with the image size of 5 inches. The successful development of compact laser TV will open a new area of home application of the laser light.

• Current Optics and Photonics
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• v.1 no.5
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• pp.491-499
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• 2017

Ghost imaging offers great potential, with respect to standard imaging, for imaging objects in optically harsh or noisy environments. It can solve the problems that are difficult to solve by conventional imaging techniques. Recently, it has become a hot topic in quantum optics. In this paper, we propose a scheme for ghost imaging based on rosette scanning, named rosette ghost imaging. Sampling a small area sampling instead of the whole object, the instantaneous field of view of rosette scanning is used as the modulation light field in ghost imaging. This scheme reduces energy loss, the number of samples, and the sampling time, while improving the quality of the reconstructed image.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.61-70
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• 2005

Airborne laser scanning system needs preprocessing which removes some objects such as buildings from the raw DSM data to construct DEM in building area because the laser pulse can't penetrate into the buildings. This study applied the mean filtering method which has various size filter to the DSM data constructed by airborne laser scanning system and decided the optimal filter size as $39{\times}39$ by analyzing the standard deviation change ratio. Also, this study could get the ${\pm}0.065m$ standard error by comparing the optimal filtering DEM and DSM raw data of airborne laser scanning. Therefore, it could know that the mean filtering method, which is presented in this study, is very effective to extract DEM in the urban area which has a low relief.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.415-421
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• 2014

In this paper, we proposed problem and improvement of halftoning using random space filling curve. Random space filling curve is developed as a solution for shortcoming which space filling curve has self-similarity. It is used to reduce regular pattern can be occurred in constant brightness area in order that randomness apply to scanning path. But there is a problem that some area along scanning path can show too bright result in halftoning using random space filling curve. In this paper, we analyzed cause of problem and proposed single pixel error diffusion as a solution method. This method can avoid over-accumulated error and show better result in halftoning.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.4
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• pp.101-107
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• 2008

Due to increased interest in environmental friendly ecological development and restoration, civil appeals concerning various environmental and landscape problems are continuously being lodged in cases where open-pit limestone mines are situated in places with eminent natural landscape. In this study, with the open-pit limestone mines located in the Baekdu mountain range as a study area, intends to contribute in recognition of various environmental problems and in the promotion of a reasonable restoration plan through high quality geo-spatial information. And it is planning to establish a method for sustained monitoring of the limestone mining by building intelligent national land information of the study area through combining Airborne Laser Scanning and Terrestrial LiDAR based surveying.

• The Journal of the Korean dental association
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• v.58 no.1
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• pp.8-18
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• 2019

This case report presents results for gingival recession coverage following gingival grafting and for gingival biotype enhancements by visualizing soft tissue volume changes using intraoral three-dimensional scanning. A 28 year old female patient with multiple gingival recessions and a 19 year old female patient with a single gingival recession on mandibular anterior area were treated. Root coverage was performed in both cases using autogenous subepithelial connective tissue harvested from palate. Intraoral 3D scan data were obatained presurgery and at 3 months, 1 year, and 2 years postsurgery. The recession areas were recovered successfully by subepithelial connective tissue graft combined with pedicle flap repositioning, and the patients showed neither further recurrence nor post-operative complication. Soft tissue biotype changes were identified by superimposing and analyzing scan data, revealing that gingival biotype was enhanced in both cases. These cases suggest that SCTG could be advantageous in terms of the gingival biotype enhancement, as well as gingival recession coverage, and intraoral 3D scanning might be suitable for assessing post-surgical gingival biotype change.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.155-166
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• 2004

The characteristics of soft clays are very important for the land development plan. This study is to investigate correlations between the engineering properties and the characteristics of clay minerals of the undisturbed clay samples obtained from Sihwa area. This study included X-Ray diffraction analysis, X-Ray fluorescence spectrometer analysis, scanning electron microscopy analysis and energy dispersive X-Ray spectrometer analysis. The correlations between the clay mineral properties and the laboratory and field testing results were investigated. The characteristics of soft clay in Sihwa area were compared with those in Yangsan and Kunsan area.