• 응용통계연구
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• 제23권2호
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• pp.305-315
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• 2010

본 논문에서는 색조영상의 R-, G-, B-성분에서 랜덤결측된 화소값들의 대체를 위한 프리퀀티스틱(frequentictic) 기법을 제공한다. 이 기법은 관측영상을 가우시안 마코프 랜덤필드 상의 실현치로서 가정하고, 주어진 화소 내의 근방 화소들이 에지 강도에 따른 서로 다른 분산을 가지는 정규분포를 따른다고 설계함으로써 에지에서 결측화소 대체값이 이질적 색상에 영향 받지 않도록 한다. 이러한 모형하에서 우도가 최대화하도록 결측화소값들을 근사 EM 알고리즘에 기반 한 방법으로 모수들을 추정하고 결측화소를 대체한다. 제안된 방법의 결과들은 보간법에 기초한 대체법과 비교하여 그 유효성을 보인다.

• 전자공학회논문지 IE
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• 제44권2호
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• pp.32-40
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• 2007

본 논문에서는 지문 영상 내부에서 특징 정보 추출의 정확성을 향상시킬 수 있는 주름선 검출 방법을 제안한다. 먼저 각 방향별 슬릿의 평균 픽셀 값과 분산에 의하여 픽셀이 주름선 후보 영역에 해당하는지를 결정하고, 그 위치에 해당하는 주름선 방향을 검출한다. 그리고 후보 영역에 해당하는 픽셀의 주름선 방향에 의하여 8개의 영상으로 분해한다. 각 방향별 분해 영상에서 주름선 후보 영역 픽셀들이 형성하는 클러스터의 길이, 주름선 방향과 픽셀 분포 방향의 일치성, 융선 방향과 픽셀 분포방향의 차, 후보 픽셀들의 평균 픽셀 값을 이용하여 주름선 클러스터를 검출한다. 마지막으로, 각 방향별 분해 영상의 주름선 클러스터들을 합성함으로써 주름선 영역을 검출한다. 제안한 방법을 구현하고 주름선 검출을 수행한 결과, 91.4%의 높은 정확성을 확인하였다.

• 대한원격탐사학회지
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• 제38권1호
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• pp.33-43
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• 2022

This study presents a method to restore an optical satellite image with distortion and occlusion due to fog, haze, and clouds to one that minimizes degradation factors by referring to the same type of peripheral image. Specifically, the time and cost of re-photographing were reduced by partially occluding a region. To maintain the original image's pixel value as much as possible and to maintain restored and unrestored area continuity, a simulation restoration technique modified with the Cycle Generative Adversarial Network (CycleGAN) method was developed. The accuracy of the simulated image was analyzed by comparing CycleGAN and histogram matching, as well as the pixel value distribution, with the original image. The results show that for Site 1 (out of three sites), the root mean square error and R² of CycleGAN were 169.36 and 0.9917, respectively, showing lower errors than those for histogram matching (170.43 and 0.9896, respectively). Further, comparison of the mean and standard deviation values of images simulated by CycleGAN and histogram matching with the ground truth pixel values confirmed the CycleGAN methodology as being closer to the ground truth value. Even for the histogram distribution of the simulated images, CycleGAN was closer to the ground truth than histogram matching.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.231-233
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• 2003

Agricultural land use generally shows specific temporal characteristics of NDVI obtained from satellite data. In terms of winter wheat, a higher value compared with other land use types in May and a considerably low value in June could be discriminative features of temporal change of NDVI. In this study, the author examined methods for estimating winter wheat sown area in sub-pixel level of coarse resolution satellite data using temporal characteristics of NDVI. Application of the methods to the major grain production area in China exhibited properly a spatial distribution pattern of winter wheat sown area.

• 천문학회보
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• 제41권2호
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• pp.35.1-35.1
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• 2016

To understand the coevolution of Brightest Cluster Galaxies (BCGs) and their host clusters, we conduct a case study on the BCGs in dynamically young and old clusters, Abell 1139 (A1139) and Abell 2589 (A2589). We analyze the pixel color-magnitude diagrams (pCMDs) using deep g- and r-band images, obtained from the CFHT observations. (1) While the overall shapes of the pCMDs are similar to those of typical early-type galaxies, the A2589-BCG tends to have redder mean pixel color and smaller pixel color deviation at given surface brightness than the A1139-BCG. (2) The mean pixel color distribution as a function of pixel surface brightness indicates that the A2589-BCG formed a larger central body by major dry mergers at an early epoch than the A1139-BCG, while they have grown commonly by subsequent minor mergers. (3) The spatial distributions of the pixels with deviated colors reveal that the A1139-BCG experienced considerable tidal events more recently than the A2589-BCG, whereas the A2589-BCG has an asymmetric compact core possibly resulting from major dry merger at an early epoch. (4) The A2589-BCG shows a very large faint-to-bright pixel number ratio compared to early-type non-BCGs, whereas the ratio for the A1139-BCG is not distinctively large. These results imply that the BCG in the dynamically older cluster (A2589) formed earlier and is relaxed better.

• 한국인터넷방송통신학회논문지
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• 제12권3호
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• pp.29-35
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• 2012

본 논문에서는 MPEG(Moving Picture Experts Group) 영상 디코더에서 영상을 압축, 비교, 복원, 저장한후 디코딩 처리하는 방법을 종래의 픽셀 단위로 처리하는 방법과는 다르게 영상의 단위 화소 주변을 군집화소로 분류한 후 이를 클러스터링하여 오버랩정도를 결정 한다. 오버랩 정도의 임계치값을 결정하는데는 패턴식별을 취한후 샘플 패턴에 대한 기하구조의 파악과 결정함수의 도출로 활용된다. 특징공간이 4차원 이상이면 주어진 패턴 구조를 시각적으로 관찰할 수 없다. 이 때, 분포구조를 고찰해 볼수 있는 방법은 군집중심간의 거리, 군집별 패턴의 수 및 표준편차 등을 이용하는 방법이다. 임계치 값을 넘는 중복화면은 소거되고 넘지않는 군집화면은 패턴인식으로 복원된후 동영상으로 구현된다. 이방법이 기존의 픽셀 단위 처리하는 방법 과는 20%정도의 메모리 감축과 15%정도의 화면 복원에 성능이 향상된 것으로 판정된다.

• 한국측량학회지
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• 제16권1호
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• pp.75-84
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• 1998

인공위성 데이터로부터 보다 자세한 정보를 취득하기 위해 혼합화소를 해석하는 방법에 대해 연구하였다. 본 연구에서는 2가지 토지피복만 혼합되어 있는 경우로 한정하였다. 정준상관분류기법에서 생성되는 정준벡터를 분석하여 혼합화소를 분류해 낼 수 있었으며, 그 기준으로 정준벡터의 요소인 정준가중치 2개의 상대적 비율을 역치로 사용하였다. 9월 1일을 전후한 TM 데이터의 다리와 물 항목에 대한 분류의 경우에, 혼합화소를 가장 적절히 분류하는 역치는 4.0으로 결정되었다. 즉 정준가중치사이의 비율이 4.0이상이면 단일피복화소이며, 4.0이하이면 혼합화소로 간주하게 된다. 정준가중치의 분포에 의해 대략적인 토지피복 구성비율도 추정할 수 있다. 실험영역에 대한 혼합화소 추출의 정확도는 90%로서 높은 수준이었다. 따라서 정준벡터분석에 의한 혼합화소 분류방법은 효용성이 있다고 판단된다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1526-1526
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• 2001

To improve the accuracy of sweetness sensor in automated sorting operations, it is necessary to clarify unevenness of the sugar content distribution within fruits. And it is expected that the technique to evaluate the content distribution in fruits contribute to the development of the near-infrared (NIR) imaging spectroscopy. Sugiyama (1999) had succeeded to visualize the distribution of the sugar content on the surface of a half-cut green fresh melon. However, this method cannot be applied to red flesh melons because it depends on information of the absorption band of chlorophyll (676 nm), which is affected by the color of the fresh. The objective of this study was to develop the universal visualization method depends on the absorption band of sugar, which can be applied to various kinds of melons and other fruits. The relationship between the sugar contents and absorption spectra of both green and red fresh melons were investigated by using a NIR spectrometer to determine the absorption band of sugar. The combination of 2$\^$nd/ derivative absorbances at 902 nm and 874 nm was highly correlated with the sugar contents. The wavelength of 902 nm is attributed to the absorption band of sugar. A cooled charge-coupled device (CCD) imaging camera which has 16 bit (65536 steps) A/D resolution was equipped with rotating band-pass filter wheel and used to capture the spectral absorption images of the flesh of a vertically half-cut red fresh melon. The advantage of the high A/D resolution in this research is that each pixel of the CCD is expected to function as a detector of the NIR spectrometer for quantitative analysis. Images at 846 nm, 874 nm, 902 nm and 930 nm were acquired using this CCD camera. Then the 2$\^$nd/ derivative absorbances at 902 nm and 874 nm at each pixel were calculated using these four images. On the other hand, parts of the same melon were extracted for capturing the images and squeezed for the measurement of sugar content. Then the calibration curve between the combination of 2$\^$nd/ derivative absorbances at 902 nm and 874 nm and sugar content was developed. The calibration method based on NIR spectroscopy techniques was applied to each pixel of the images to convert the 2$\^$nd/ derivative absorbances into the Brix sugar content. Mapping the sugar content value of each pixel with linear color scale, the distribution of the sugar content was visualized. As a result of the visualization, it was quantitatively confirmed that the Brix sugar contents are low at the near of the skin and become higher towards the seeds. This result suggests that the visualization technique by the NIR imaging spectroscopy could become a new useful method fer quality evaluation of melons.

• 전자공학회논문지A
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• 제32A권12호
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• pp.122-129
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• 1995

The most important feature of a-Si TFT is dense localized states such as dangling bonds which exist in tis bandgap. Electrons trapped by localized states dominate the potential distribution in the active a-Si region ,and influence the performance of a-Si TFT. In this paper, we describe the electrical characteristics of a-Si TFT with respect to trap distribution within bandgap, electron mobility and interface states using 2-Dimensional device simulator and compare the result of simulation with measurements. Using the mixed-mode simulator, we can predict the potential variation of pixel which causes residual image problem during the turn-off of a-Si TFT driving circuit. Therefore it is possible to consider trade-off between potential variation of pixel and turn-on current of a-Si TFT for the optimized driving circuit.

• 천문학회보
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• 제36권2호
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• pp.103.2-103.2
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• 2011

We measure the degree of polarization of the lunar regolith to map the distributions of the age and the particle size. We use a 12cm refracting telescope with a 2k-square pixel color CCD (R band) and a polarization filter. The angular resolution obtained is 3.02 km/pixel. Our goal is to obtain a map of the lunar particle size distribution on the lunar regolith and then that of the age distribution. Polarization of the light scattered by lunar surface contains information on their mean particle size. The mean particle size of the lunar surface has been decreased by continued micro-meteoroid impact over a long period. One can estimate the age of the lunar surface if the mean particle size is known. Particle sizes can be measured through observations of polarization because the mean particle size is related to the maximum polarization and albedo. The age and the particle size of the lunar regolith can give vital information for the future lunar exploration.