• 천문학회보
• /
• 제40권2호
• /
• pp.50.1-50.1
• /
• 2015

The origin of globular cluster (GC) color bimodality, which is one of the salient phenomena observed in most large galaxies, has not yet been fully resolved. The phenomenon has conventionally been interpreted as a bimodal metallicity distribution based on an assumption of linear GC color-metallicity relations (CMRs). Recent studies however suggest that nonlinear GC CMRs can cause a bimodal color distribution even from a single-peaked metallicity spread. Using photometric and spectroscopic data on GCs in NGC 5128 (Cen A) and NGC 4594 (Sombrero), we investigate the nonlinearity of GC CMRs and compare the observed GC CMRs with the predictions of stellar population simulation models. Our careful selection of old GCs effectively reduces the scatter and reveals the nonlinear nature of the GC CMRs for various colors. The overall shape of the observed CMRs agrees well with that of the modeled CMRs, while offsets are present for some colors. We discuss the implications of our results in terms of the GC color bimodality and GC formation in NGC 5128 and NGC 4594.

• 한국인쇄학회지
• /
• 제16권3호
• /
• pp.121-131
• /
• 1998

The object color does not look same under the different light source. It depends on the surface spectral reflectance and the spectral distribution of light source. Therefore we should find the surface spectral reflectance of object color and the spectral distribution of light source for color reproduction. Using Wiener estimation, we can estimate the spectral reflectance from low dimensional images obtained with multi-band image acquisition system. The kind and the number of imaging filters have the effect on the estimation of the spectral reflectance. Therefore it is important that optimal filters are selected to minimize the error of the result. In this paper, we describe methods to select optimal filters with minimum error between measured and estimated surface spectral reflectance and to estimate surface spectral reflectance of Munsell color chart from six multi-band images by using Wiener estimation.

• 한국인쇄학회:학술대회논문집
• /
• 한국인쇄학회 1998년도 추계 논문 발표회 논문집
• /
• pp.1-6
• /
• 1998

The object color does not look same under the different light source. It depends on the surface spectral reflectance and the spectral distribution of light source. Therefore we should find the surface spectral reflectance of object color and the spectral distribution of light source for color reproduction. Using Winer estimation, we can reconstruct the spectral reflectance from low dimensional images obtained with a few filters. The kind and the number of filters have the effect on the estimation of the spectral reflectance. Therefore it is important that optimal filters are selected to minimize the error of the result. In this paper, we describe methods to select optimal filters with minimum error between measured and estimated surface spectral reflectance and to estimate surface spectral reflectance of Munsell color from six band images by using Wiener estimation.

• 한국과학예술포럼
• /
• 제26권
• /
• pp.179-187
• /
• 2016

본 연구는 도시소공원 색채환경에 관한 연구로서 사회체육시설 영역을 중심으로 서울과 동경사례를 비교, 분석하여 색채환경 차이를 이해하고 시민건강증진을 위한 도시소공원 사회체육시설 색채계획을 수립하기 위한 자료로 활용하고자 한다. 서울과 동경에 위치한 순환선인 2호선과 야마노테선을 중심으로 인근 지하철역에 위치한 도시소공원을 선정, 분광측색기로 환경색채를 측정하였다. 서울 도시소공원 4곳, 동경의 도시소공원 4곳 총 8곳을 직접방문하여 현장조사를 실시하였으며 도시소공원의 사회체육시설물, 공원시설물, 바닥 포장면으로 구분하여 조사하였다. 연구결과는 다음과 같다. 첫 번째 서울과 동경의 도시소공원의 사회체육시설 영역의 환경색채는 전반적으로 Y계열(Y, YR, GY)의 색채의 분포가 높게 나타났다. Y계열 다음으로 서울의 경우 B계열(B, BG, PB), 동경은 R, P계열로 나타나 색상분포가 차이가 있는 것으로 나타났다. 두 번째, 사회체육시설물의 경우, 서울보다 동경이 다양한 색상분포를 보였고, 서울이 명도가 다소 높게 나타나 밝은 색채가 시설물에 적용되었고 동경의 경우 원색에 가까운 고채도의 색채가 적용되고 있었다. 세 번째, 공원시설물 색채는 서울과 동경이 비슷한 명도, 채도값을 나타냈고, 색상분포에서 서울은 Y계열-B계열 순으로 높게 나타나며, 동경은 Y계열-R계열 순으로 높게 나타나고 있다. 바닥포장면의 명도와 채도도 서울과 동경이 비슷하게 나타나지만 색상분포에서 차이를 보였다. 향후, 색채의 생리적, 심리적 반응에 대한 연구결과를 사회체육시설 색채에 적용하는 것이 바람직하다고 사료된다.

• 한국멀티미디어학회논문지
• /
• 제12권5호
• /
• pp.633-643
• /
• 2009

본 논문에서는 다양한 색상을 가지는 입력 영상의 화질올 잘 유지하면서, 객체들 간 시각적인 차이를 뚜렷하게 표현하기 위해 색의대비 기반 템플릿을 이용하는 색상 변환 알고리즘을 제안한다. 이 방법은 CIE $L^{\ast}a^{\ast}b^{\ast}$색상 공간 중 유채색의 $a^{\ast}b^{\ast}$평면상에 분포된 입력 영상파 템플릿의 색상 데이터를 이용한다. 템플릿은 색상간의 대비효과를 고려하여 만들어지며, 사용자가 임의로 지정한 가준 색상들을 기반한 그라데이션 영상의 색상 분포를 표시하는 칙선 또는 곡선의 형태를 가진다. 또한, 만들어진 템플릿을 스플라인 곡선으로 모델링하고, 모텔링된 곡선의 제어점을 변형함으로써 간단하게 다른 기준 색상을 가지는, 새로운 탱플릿을 만들 수도 있다. 탬플릿을 이용한 색상 변환은 회귀분석과 칼라 매칭을 통해 이루어지며, 입력 영상의 색상분포를 템플릿의 색상 분포와 유사하게 변형함으로써 입력 영상의 색상 일관성올 유지하였다.

• 정보통신설비학회논문지
• /
• 제9권2호
• /
• pp.73-79
• /
• 2010

The most popular technique for image retrieval in a heterogeneous collection of color images is the comparison of images based on their color histogram. The color histogram describes the distribution of colors in the color space of a color image. In the most image retrieval systems, the color histogram is used to compute similarities between the query image and all the images in a database. But, small changes in the resolution, scaling, and illumination may cause important modifications of the color histogram, and so two color images may be considered to be very different from each other even though they have completely related semantics. A new method of color feature representation based on the 3-dimensional RGB color map is proposed to improve the defects of the color histogram. The proposed method is based on the three 2-dimensional projection map evaluated by projecting the RGB color space on the RG, GB, and BR surfaces. The experimental results reveal that the proposed is less sensitive to small changes in the scene and that achieve higher retrieval performances than the traditional color histogram.

• Journal of information and communication convergence engineering
• /
• 제2권2호
• /
• pp.123-127
• /
• 2004

The most popular technique for image retrieval in a heterogeneous collection of color images is the comparison of images based on their color histogram. The color histogram describes the distribution of colors in the color space of a color image. In the most image retrieval systems, the color histogram is used to compute similarities between the query image and all the images in a database. But, small changes in the resolution, scaling, and illumination may cause important modifications of the color histogram, and so two color images may be considered to be very different from each other even though they have completely related semantics. A new method of color feature representation based on the 3-dimensional RGB color map is proposed to improve the defects of the color histogram. The proposed method is based on the three 2-dimensional projection map evaluated by projecting the RGB color space on the RG, GB, and BR surfaces. The experimental results reveal that the proposed is less sensitive to small changes in the scene and that achieve higher retrieval performances than the traditional color histogram.

• 천문학회지
• /
• 제38권3호
• /
• pp.345-355
• /
• 2005

We present a photometric study of the star cluster system in the merging galaxy NGC 1487, based on the BI photometry obtained from the F450W and F814W images in the HST /WFPC2 archive data. We have found about 560 star cluster candidates in NGC 1487, using the morphological parameters of the objects. We have investigated several photometric characteristics of the clusters: color-magnitude diagrams (CMDs), color distribution, spatial distribution, age, size and luminosity function. The CMD of the bright clusters with 18.5 < B < 24 mag in NGC 1487 shows three major populations of clusters: a blue cluster population with $(B-I){\le}0.45$, an intermediate-color cluster population with $0.45<(B-I){\le}1.55$, and a red cluster population with (B - I) > 1.55. The intermediate-color population is the most dominant among the three populations. The brightest clusters in the blue and intermediate- color populations are as bright as $B{\approx}18mag$ ($M_B{\approx}-12mag$), which are three magnitudes brighter than those in the red population. The blue and intermediate-color clusters are strongly concentrated on the bright condensations, while the red clusters are relatively more scattered over the galaxy. The CMD of these clusters is found to be remarkably similar to that of the clusters in the famous interacting system M51. From this we suggest that the intermediate-color clusters were, probably, formed during the merging process which occurred about 500 Myrs ago.

• 천문학회보
• /
• 제40권2호
• /
• pp.33.2-33.2
• /
• 2015

The color distribution functions (CDFs) of globular clusters (GCs) in individual early-type galaxies show great diversity in their morphology. Based on the conventional "linear" relationship between colors and metallicities of GCs, the inferred GC metallicity distribution functions and thus their formation histories should be as diverse as they appear. In contrast, an alternative scenario rooted in the "nonlinear" nature of the color-to-metallicity transformation finds the various CDFs pointing systematically to a simple picture, i.e., such a high degree of variety stems predominately from only one parameter, the mean metallicity of GCs. The simulated CDFs of GCs aimed to reproduce 67 massive early-type galaxies from the ACS Virgo & Fornax Cluster Survey show that over 70% of the CDFs concur fully with the nonlinearity scenario. We discuss our new findings in terms of early-type galaxy formation in the cluster environment.

• 한국발생생물학회지:발생과생식
• /
• 제15권4호
• /
• pp.325-329
• /
• 2011

본 연구는 수정란 이식에 의해 생산된 울릉칡소의 모색분포의 조사를 통해 울릉칡소의 모색 고정에 필요한 기초자료로 활용하고자 실시하였다. 1. 울릉칡소의 모색 분포는 황모 24.3%(67/276두), 흑모 13.0%(36/276두)와 호반모 62.7% (173/276두)의 분포를 보였으며, 입식우의 호반모 출현율이 66%(105/159두)로 관내이식에 의해 생산된 칡소의 호반모 비율 58.1%(68/117두)보다 다소 높은 경향이었다. 2. 성별에 따른 모색의 분포를 조사한 결과, 수컷의 경우 황모의 비율이 18.1%(25/138두)로 암컷의 31.4%(43/137두)에 비해 출현율이 낮은 반면, 호반모의 비율은 68.1%(94/138두)로 암컷의 56.9%(78/137두)에 비해 다소 높게 나타났다. 3. 비경의 흑반점의 강약에 따른 호반모의 발현 양상을 분석한 결과, 비경의 흑반점이 강할수록 호반모의 흑모 발현율이 높은 것으로 사료된다.