• ETRI Journal
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• 제26권4호
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• pp.332-343
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• 2004

One of the recent and most significant technical properties can be expressed as "digital convergence," which is helping lead the technical paradigm into a ubiquitous environment. As an initial trial of realizing a ubiquitous environment, the convergence between broadcasting and telecommunication fields is now on the way, where it is required to develop a scalable video coding scheme for one-source and multi-use media. Traditional scalable video coding schemes have, however, limitations for higher stable picture quality especially on the region of interest. Therefore, this paper introduces an adaptive scanning method especially designed for a higher regional-stable picture quality under a ubiquitous video coding environment, which can improve the subjective quality of the decoded video by most-preferentially encoding, transmitting, and decoding the top-priority image information of the region of interest. Thus, the video can be more clearly visible to users. From various simulation results, the proposed scanning method in this paper can achieve an improved subjective picture quality far better than the widely used raster scan order in conventional video coding schemes, especially on the region of interest, and without a significant loss of quality in the left-over region.

• 한국정밀공학회지
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• 제20권9호
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• pp.197-204
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• 2003

This study proposes a method to reduce errors in scanning object and registration using a laser scanner. The method consists of 3 stages. First, there is an error induced by the difference of the distance between the probe and the object. It is possible to reduce the error by planning a scanning strategy: object setting, scan path. Second, the scan data of the tooling ball affects calculating the tooling ball center. A z-direction compensation is given to calculate more accurate registration points. Third, three points are used to determine a coordinate transformation on each frame. The maximum error usually lies on the third tooling ball in the conventional merging method. LSM (Least Square Method) is applied to a coordinate transformation to reduce the registration error.

• Nuclear Medicine and Molecular Imaging
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• 제42권sup1호
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• pp.134-136
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• 2008

Neuroblastoma is the most common extracranial solid tumor in children. In diagnostic assessment of neuroblastoma, $^{18}F-FDG$ PET has been reported to have high diagnostic performance, especially, very high sensitivity in staging, restaging, and assessment of therapeutic efficacy. In comparison with conventional diagnostic imaging modalities including a, bone scan, and MIBG scan, $^{18}F-FDG$ PET showed better diagnostic performance. According to clinical research data hitherto, $^{18}F-FDG$ PET is expected to be an effective diagnostic tool in the management of neuroblastoma.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1097-1100
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• 1999

Due to the significant computation of full search in motion estimation, extensive research in fast motion estimation algorithms has been carried out. However, most of the algorithms have the degradation in predicted images compared with the full search algorithm. To reduce an amount of significant computation while keeping the same prediction quality of the full search, we propose a fast block-matching algorithm based on gradient magnitude of reference block without any degradation of predicted image. By using Taylor series expansion, we show that the block matching errors between reference block and candidate block are proportional to the gradient magnitude of matching block. With the derived result, we propose fast full search algorithm with adaptively determined scan direction in the block matching. Experimentally, our proposed algorithm is very efficient in terms of computational speedup and has the smallest computation among all the conventional full search algorithms. Therefore, our algorithm is useful in VLSI implementation of video encoder requiring real-time application.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.199-202
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• 2002

In general, the background light produced during the reset period deteriorates the dark room contrast ratio in AC PDP. In this paper, we propose a modified ramp reset pulse that can reduce the background light to imperceptible level. In the new reset waveform, the discharges between the scan and sustain electrodes are minimized by applying a positive bias voltage to the sustain electrode and only the weak discharges between the scan and address electrodes occur during the reset period. We adopted a MgO coated phosphor layer to get the same level of voltage margin in the new reset pulse scheme compared to that of the conventional ramp reset pulse one. As a result, the voltage margin is maintained at the same level and the dark room contrast ratio is improved dramatically.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1827-1829
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• 2000

To replace the dual scan system by single scan in large ac plasma display(PDP), the addressing time should be reduced by modifying cell structure and driving circuits. Moreover. the luminance of the PDP can be also increased with the decrease in the addressing time. In this paper, various shapes of bus and address electrode have been investigated to reduce the addressing time in ADS driving method. The experimental results show that the addressing time can be reduced more than 30% compared to the conventional type by modifying the electrodes without reducing the luminance of the PDP.

• Journal of Information Display
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• 제2권2호
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• pp.39-44
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• 2001

The conditions of the wall charges and priming particles in a unit discharge cell in AC PDP seriously affect the addressing discharge characteristics in the driving method with ramped setup pulse. Moreover, the discharge conditions at the end of the scan line may be different from the first scan line because of the difference of about 1ms address time. Consequently, the addressing time and its dispersion may be different for any two discharge cells that lead to misfiring and the increase in the total addressing time. In order to improve the addressing time and its dispersion, we have applied different addressing voltage at each cell such as progressively increase pulse voltage instead of constant one. As a result, the addressing time and its dispersion of all cells were improved by about 30% compared with the conventional driving method.

• Journal of Information Display
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• 제2권1호
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• pp.10-13
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• 2001

The addressing time can be reduced by modifying cell structure and/or driving circuits in order to replace the dual scan system by single scan in large ac plasma display panel(PDP). Moreover, the luminance of the PDP can also be increased by decreasing the addressing time. In this paper, various shapes of bus and address electrodes have been investigated with the aim of reducing the addressing time in ADS driving method. The experimental results show that the addressing time can be reduced by more than 30% compared with the conventional type by modifying the electrodes without reducing the luminance of the PDP.

• 제어로봇시스템학회논문지
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• 제22권1호
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• pp.46-52
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• 2016

We propose a new type of semi-global matching (SGM) in order to solve a streaking problem arising from conventional SGM. Conventional SGM imposes a penalty to a pixel when the disparity of the pixel differs from that of the previous pixel along a scan path, and thus, disparity changes are not easily allowed, causing the streaking effect. The road surface is an appropriate target for such an effect, because the colors of the surfaces are very similar, and the image pixels corresponding to the surfaces show disparities that change very smoothly along the viewing direction. In contrast to conventional SGM, the new type of SGM imposes penalties depending on the disparity gradients, and thus, the streaking effect is controlled. The experimental results show the effectiveness of the proposed SGM method.

• 비파괴검사학회지
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• 제35권5호
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• pp.299-306
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• 2015

일반 위상배열 시스템에서는 다수의 압전소자를 가지는 탐촉자의 개별 소자에 인가하는 시간지연을 조절함으로써 초음파빔을 전자적으로 제어하고 초음파 영상을 획득한다. 반면, full matrix capture(FMC) 기술은 위상배열 탐촉자에 대해 하나의 소자에서 초음파를 입사시킨 신호를 모든 압전소자에서 수신하고, 이 방법으로 모든 가능한 송수신 조합의 신호 데이터를 수집하는 방법이다. 이 FMC 데이터는 후처리를 통해 초음파 영상으로 재구성될 수 있으며, 기존 위상배열 초음파 영상과 동등한 영상뿐만 아니라 가상적으로 관심영역의 모든 지점에 집속하여 분해능과 선명도가 향상된 total focusing method(TFM) 영상으로도 합성이 가능하다. 본 논문에서는 일반 위상배열장치를 이용하여 FMC가 가능하도록 시스템을 구현하고, 취득된 FMC 신호로부터 sector B-scan 및 TFM 이미지를 영상화하는 알고리즘에 대한 연구를 수행하였다.