• 한국표면공학회지
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• 제23권2호
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• pp.24-29
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• 1990

The TiN filmms were deposited on the stainless steel substrates by BARE techinique in order to investigate the effects of process parameters such as source-to-substate distance (15-35cm), N2 pressure(4$\times$10-10 -1$\times$10-3mb)and bias voltage(O-2000V), on the deposition rate, the concentration ratio [N/Ti] and the surface color of the films. The deposition rate was deduced from the weight measurement, the [N/ti] ratio by ESCA. The deposition rate decreased with a relationship of=40.2/D2 where D was source-to-substrate distance. The effect of the bias voltage and the N2pressure on the deposition rate, however, appeared negligble. The [N/Ti] ratio was in the narrow range of 0.7 tp 0.8 It increased slightly with the N2 partial pressure and deceased with the source-to-substrate distance. It was confired by ESCA that a significant amount of oxygen and carbon was contaminated after deposition in the top surface of TiN films. The surface color of TiN film was changed from light gold yellow to reddish gold yellow with increasing [N/Ti] ratio.

• 천문학회보
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• 제44권1호
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• pp.85.4-85.4
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• 2019

Supernovae (SNe) are well known as good cosmological distance probes owing to their brightness and well-characterized light curve property. Specifically, type Ia SNe have contributed greatly to our understanding of acceleration of cosmic expansion. However, type IIP supernovae occur most frequently (~ 40% of all) at low and high redshift. As knowledge on the type IIP SNe increases, distance measurement methods using type IIP SNe have evolved. In this study, we apply Photometric Color Method (PCM), which needs only photometric data using properties of plateau on type IIP SNe light curves, to measure distances of several host galaxies of SNe IIP from the Intensive Monitoring Survey of Nearby Galaxies (IMSNG). The daily monitoring of galaxies at < 50 Mpc allows us to construct a dense light curve of SNe that occurred in our target galaxies. We observed two SNe IIP, SN2014cx and SN2017eaw and measured distances to their host galaxies, NGC 337 and NGC6946 respectively. Our results are comparable with other secondary distance measurement methods, 4-5 Mpc, however smaller than the result derived from the Tip of Red Giant Branch (TRGB) method, $6.7{\pm}0.2$ and $7.7{\pm}0.3Mpc$.

• 컴퓨터교육학회논문지
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• 제8권1호
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• pp.81-91
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• 2005

본 논문에서는 칼라와 에지 정보를 이용한 내용기반 영상검색 기법을 제안하였다. 기존의 RGB 공간 정보를 이용하기 보다는, 시각적 인식에 보다 중점을 둔 HSI칼라 공간에서 고찰하였다. 비슷한 류의 색을 대표색으로 통합 표현하여, 개선된 칼라 정보 이용법을 본 연구에서 제안하였다. 또한 칼라 정보만을 이용했을 때의 시스템 성능상의 결점을 보완하기 위하여, 효율적인 에지 디텍션 기법을 함께 사용하였다. 칼라와 에지 기법을 통합함에 있어서, 각각의 기법에 적절한 가중치를 배분함으로써 시스템 성능을 실험적으로 향상시켰다.

• 한국정보통신학회논문지
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• 제6권5호
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• pp.789-795
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• 2002

컬러 이미지는 Gray Scale 이미지와는 달리 3가지 채널의 조합으로 이루어지고 방대한 정보량 때문에 효과적인 이미지 분할이 어렵다. 본 논문에서는 범용성 있는 Color Morphological Pyramids(CMP)구조를 제안하고, 그를 이용한 이미지 분할을 보인다. 이미지 피라미드 구조는 최초 이미지의 반복적인 필터링과 샘플링에 의해 면적비가 $2^{\int}({\int}=1,2,....,N)$이 되는 순차적 이미지 계열이다. 본 방법에서는 CMP를 이용하여 RGB, HSI, CMY 등의 컬러 공간에서 연속적인 필터링 처리로 불필요한 크기의 물체 및 잡음을 제거하고, 다운샘플링과정으로 해상도를 낮춰준다. 생성된 CMP에서 인접 레벨 이미지간에는 이웃한 픽셀 벡터간의 상대거리를 이용한 연결식을 사용하여 새 레벨의 이미지를 생성한 후 이를 이미지 분할한다. 이미지 분할실험을 통하여 본 방법의 유효성을 검증한다.

• Journal of Computational Design and Engineering
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• 제2권3호
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• pp.183-194
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• 2015

This paper proposes a novel method for visualizing the thickness and clearance of 3D objects in a polyhedral representation. The proposed method uses the distance field of the objects in the visualization. A parallel algorithm is developed for constructing the distance field of polyhedral objects using the GPU. The distance between a voxel and the surface polygons of the model is computed many times in the distance field construction. Similar sets of polygons are usually selected as close polygons for close voxels. By using this spatial coherence, a parallel algorithm is designed to compute the distances between a cluster of close voxels and the polygons selected by the culling operation so that the fast shared memory mechanism of the GPU can be fully utilized. The thickness/clearance of the objects is visualized by distributing points on the visible surfaces of the objects and painting them with a unique color corresponding to the thickness/clearance values at those points. A modified ray casting method is developed for computing the thickness/clearance using the distance field of the objects. A system based on these algorithms can compute the distance field of complex objects within a few minutes for most cases. After the distance field construction, thickness/clearance visualization at a near interactive rate is achieved.

• 한국정보통신학회논문지
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• 제17권12호
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• pp.2927-2936
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• 2013

본 논문에서는 3D 콘텐츠 생성 시 필요한 깊이 영상의 화질 개선을 위하여 잡음 제거 기법과 홀 채움 기법을 제안한다. 제안하는 기법에서는 컬러 영상과 깊이 영상을 모두 이용하게 된다. 먼저 입력된 컬러 영상을 RGB 색상계에서 HSI 색상계로 변환하여 밝기 영상을 생성한다. 그리고 깊이 영상에서 기준 화소와 주변 화소간의 거리 값, 깊이 값의 차이를 구하고 컬러 영상의 밝기 값 차이를 계산하여 제안하는 잡음 제거 기법에 이용한다. 이후 홀을 탐색하여 홀과 주변 화소간의 거리, 컬러 영상의 밝기 값 차이를 제안하는 홀 채움 기법을 적용하여 깊이 영상 내에 존재하는 홀을 채우게 된다. 마지막으로 실시간 환경에 적용하기 위하여 제안하는 기법을 GPU로 병렬화하여 속도 향상을 하고자 하였다. 실험을 통하여 제안한 기법이 기존 기법에서 발생하는 경계 부분의 흐려짐 현상을 줄이면서 홀을 채우는 것을 확인하였다.

• 한국환경보건학회지
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• 제7권1호
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• pp.21-31
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• 1981

This survey was carried out to investigate the temperature, pH value, nitrogen (ammonia, nitrite, nitrate), turbidity, color, chloride ion, $KMnO_4$ consumed, and hardness as chemical analysis of the tap water in Seoul city area during the period from September to Octobor, 1979, and to observe the differences among the values by the distance from the water purification plant and by the district supplied tap water from-the each water purification plant. The results obtained were as follows: 1) An average of the water temperature was $19.8\pm 0.2\circ$C. 2) An average of pH was $7.18\pm 0.02$. The difference among each district was statistically significant (p<0.01), but it was not observed among each distance. 3) An average of turbidity was $1.25\pm 0.12$ ppm. The difference among each district was highly significant (p<0.01), respectively, but not among each distance. 4) An average of color was $1.43\pm 0.16$ ppm, and there were statistically significant differences by the distance and by the district (p<0.01). 5) An average of ammonia nitrogen was $0.022\pm 0.005$ ppm. The differences among each distance, and district were statistically significant (P<0.01). 6) An average of nitrite nitrogen was $0.0050\pm 0.0013$ ppm, and the difference among each distance was highly significant (p<0.01), respectively, and each district showed statistical significance (p<0.01). 7) An average of nitrate nitrogen was $0.82\pm 0.08$ ppm. The difference among each district was significant (p<0.05), and each distance showed high significance (p<0.01). 8) An average of $KMnO_4$ consumed was $3.73\pm 0.16$ ppm, and the difference among each district was significant (p<0.05), but it was not observed among each distance. 9) An average of chloride ion was $8.56\pm 0.28$ ppm, and the difference among each district was higly significant (p<0.01), respectively, but it was not observed among each distance. 10) An average of hardness was $40.69\pm 1.17$ ppm, and there was statistically significant difference by each district (P<0.01), but not by distance. 11) The interrelation between temperature and pH of the tap water revealed the negative correlation from the coefficient of it as showed r=-0.6073 and p<0.01. 12) Except water temperature, there were negative correlationships between pH and other water qualities. 13) Correlation coefficients of $KMnO_4$ comsumed and ammonia nitrogen, nitrite nitrogen were statistically significant but that of $KMnO_4$ consumed and nitrate nitrogen showed no statistical correlationship. 14) Ammonia nitrogen seems to have high correlationship with nitrite nitrogen(r= +0.6669), but not with nitrate nitrogen. 15) Nitrate nitrogen seems to have statistically significant correlationship with nitrite nitrogen (r=+0.4959), but not with ammonia nitrogen. 16) The interrelation between chloride ion and hardness of the tap water revealed positive correlation from the coefficient of it as showed as r=+0.4888 and p<0.01.

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.449-456
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• 2012

For two well-known modulation methods, stepwise current modulation (SCM) and pulse width modulation (PWM), the effects of driving current modulation conditions on chromaticity were experimentally investigated in a white LED lighting system. For the experimental implementation of both SCM and PWM, a white LED lighting was fabricated using phosphor converted (PC) white light emitting diodes (LEDs) and a driving circuit module was developed. By using them, the variations of illuminance, color coordinates, and spectrum were evaluated under various forward current conditions. Through the analysis in color coordinates, yellow shift in SCM and blue shift in PWM were observed on chromaticity diagrams with increasing average driving current. In addition, in order to analyze color deviation quantitatively, color distance before and after current increase, and the correlated color temperature (CCT) were calculated. As a result, for the white LED lighting in both modulation conditions, the maximum difference in the calculated CCT was obtained close to 1000 K. It means that careful consideration is required to be taken in the design of illumination systems to avoid serious problems such industrial accidents.

• Restorative Dentistry and Endodontics
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• 제49권1호
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• pp.7.1-7.11
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• 2024

Objectives: This study aimed to evaluate the impact of substrate color and interface distance on the color adjustment of 2 single-shade composites, Vittra APS Unique and Charisma Diamond One. Materials and Methods: Dual disc-shaped specimens were created using Vittra APS Unique or Charisma Diamond One as the center composite, surrounded by shaded composites (A1 or A3). Color measurements were taken with a spectrophotometer against a gray background, recording the color coordinates in the CIELAB color space. Illumination with a light-correcting device and image acquisition using a polarizing filter-equipped cell phone were performed on specimens over the same background. Image processing software was used to measure the color coordinates in the center and periphery of the inner composite and in the outer composite. The color data were then converted to CIELAB coordinates and adjusted using data from the spectrophotometer. Color differences (ΔE₀₀) between the center/periphery of single-shade and outer composites were calculated, along with color changes in single-shade composites caused by different outer composites. Color differences for the inner composites surrounded by A1 and A3 were also calculated. Data were analyzed using repeated-measures analysis of variance (α = 0.05). Results: The results showed that color discrepancies were lowest near the interface and when the outer composite was whiter (A1). Additionally, Charisma Diamond One exhibited better color adjustment ability than Vittra APS Unique. Conclusions: Color discrepancies between the investigated single-shade composites diminished towards the interface with the surrounding composite, particularly when the latter exhibited a lighter shade.

• 환경위생공학
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• 제13권2호
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• pp.139-146
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• 1998

The characteristics of color and COD removal for dyeing-wastewater using electrochemical reaction were investigated. >From the result, the removal efficiency of color and COD were increased with increase of temperature, decrease of electrode distance, increase of electrolyte concentration and increase of potential and these were obtained above 99%, above 75% within 30 min, individually. Cause of higher COD removal efficiency, it is more suitable that dyeing-wastewater is treated by electrolytic treatment prior to biological treatment. It is concluded that the electrolytic treatment of dyeing-wastewater can be used as the effective and economical method in practical treatment.