• 한국방사선학회논문지
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• 제10권6호
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• pp.419-425
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• 2016

whole abdomen CT촬영에서 표재성 장기에 해당하는 생식선 부위의 선량을 줄이고 화질에 영향을 적게 주기 위한 차폐재를 제작하여 유용성을 확인하였다. 기존의 bismuth 재질과 비슷한 효과를 가지는 silicone 22 mm, aluminum 7.3 mm를 제작하였다. non shield, bismuth, silicone 22 mm, aluminum 7.3 mm 차폐재를 이용하여 생식선의 피폭 선량 감쇠, 영상의 CT number와 noise 변화, AAPM 팬텀에서 CT number, noise, uniformity를 측정하여 비교 실험하였다. 결과에서 bismuth 29.96%, silicone 22 mm 13.10%, aluminum 7.3 mm 18.27%로 피폭 선량이 감소되었다. 그러나 bismuth 재질의 경우 영상의 CT number 변화가 크고, AAPM 팬텀 영상검사 uniformity 항목에서 부적합으로 측정되어 생식선과 같은 표재성 장기에서 화질 변화가 큰 것으로 나타났다. 생식선과 같은 표재성 장기의 경우 silicone 22 mm, aluminum 7.3 mm의 차폐재를 사용한다면 화질 변화를 줄이면서 방사선 피폭을 줄이는데 도움이 될 것이라 판단된다.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.83-89
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• 2011

Diesel engines can produce higher fuel efficiency and lower $CO_2$ emission, they are subject to ever more stringent emission regulation. However, there are two major emission concerns fo diesel engines like such as particulate matter (PM) and nitrogen oxides (NOx). Moreover, it is not easy to satisfy the regulations on the emission of NOx and PM, which are getting more strengthened. One of the solutions is to apply the new combustion concept using multistage injection such as HCCI and PCCI. The other solution is to apply after-treatment systems. For example, lean NOx trap catalyst, Urea-SCR and others have various advantages and disadvantages Especially, Urea-SCR system have advantages such as a high conversion efficiency and a wide operation conditions. Hence the key factor to implementation of Urea-SCR technology, good mixing of urea(Ammonia) and gas, reducing Ammonia slip. Urea mixer components are required to facilitate evaporation and mixing because the liquid state of urea poses significant barriers for evaporation, and the distance to mixer is the most critical that affect mixer performance. In this study, to find out the distance from injector to mixer and simulation factor, a laser diagnostics and high speed camera are used to analyze urea injector spray characteristics and to present a distribution of urea solution in transparent manifold In addition, Droplet Uniformity Index is calculated from the acquired images by using image processing method to clarify the distribution of spray.

• 복식
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• 제50권
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• pp.51-68
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• 2000

This study is intended to examine the common features of costume images in science-fiction (SF) movies that deal with current socio-cultural situations by examining their themes and tones about the future it can be generally concluded that costume images of SF movies are divided into two patterns : one inheriting traditional styles constructed on linear progress and the other based on dismantiling the tradition. this analysis is made through the research of actual cinematic contexts on the common features of multiple styles shaping the two patterns of costume images. The results can be summarized as the following: The former is related with the future built up on the basis of belief in reasonal progress rooted in the Enlightenment reasonable plan for ideal social order and strong faith in uniformity. So It shows functional uniformity disregarding wasteful competitiveness in consumption and luxuriousness and clothing that has the aesthetic value of purity without emphasizing human body or sensuality are presented. On the other hand SF movies which show the uncertain costume image as the meaning of dismantling of tradition take up a rather critical view of assumption that society can move toward utopian future as it searches future images in the notion of hetero-topia by emphasizing pluralism consequently as for clothing diversity and uncertainty in post-modern style are presented destroying modernistic dichotomy and the assumption of Utopian clothing made in the notion of modern progressivism.

• 한국의류학회지
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• 제24권1호
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• pp.128-137
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• 2000

A range of suede-like samples were collected including woven fabric type, nonwoven fabric type, and natural suede(sheep). The surface textures of these suede-like fabrics are rather diverse and different from the plain filament type fabrics since there are a lot of fine surface free fiber ends. Physical and mechanical measurements were carried using the KES equipments. Based on the Kawabata-Niwa translational equation, primary hand values and THV were calculated. Uniaxial tensile tests were performed. Using glossmeter, the reflectance pattern was analyzed at different incidence and receiving angles. In order to capture the surface images of the specimens, a CCD camera and frame grabber connected to a PC were employed. The reflectance uniformity of the images was measured with line-profile analysis and standard deviation values of the profile of the images were calculated. After the multiscale wavelet transfermation, correlation among the transformed image was analyzed at each scale. The reflectance uniformity of the natural suede was better than that of nonwoven type suede, while that of woven type suede was the last among the selected three samples(natural suede, nonwoven type, woven type). The correlation analysis among images has shown the possibility of using the wavelet transformation of the images as one of the measures to detect similarities among the textured specimens.

• 대한기계학회논문집A
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• 제21권1호
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• pp.1-11
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• 1997

Austomated visual inspection(AVI) capability has become an important key component in the automated manufacturing system. In such a visual inspection system an intensity(or color) image of a scene is quickly affected by optical property of objects, condition and roughness of surface, lens and filters, image sensor property and lighting system. In particular, the lighting system disign is the most important factor, since it affects overall performance of the visual system. For fast and cheap automated visual inspection system it is important to obtain the good image quality which results from careful attention to the design of the lighting system. In this paper, the lighting subsystem of AVI system is analysed for the inspection of printed circuit board(PCB) patterns. The spectral reflectance of materials, which are composed of PCB, is measured for choosing the light source. The reflection property is theoretically obtained by a reflection model and also obtained by experiments which measure intensity with varying the viewing direction of image sensor and the lighting direction of illuminator. The illumination uniformity of a ring-type illuminator. The lighting system is designed based upon the experimental results and theoretial analysis.

• 대한디지털의료영상학회논문지
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• 제12권2호
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• pp.127-132
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• 2010

In this study, the correlation among the changes of Modulation Transfer Function(MTF) in the noise and high-contrast resolution and the change of Contrast to noise ratio(CNR) in the low-contrast resolution will be examined to investigate the estimation of image quality according to the type of algorithms. The image data obtained by scanning American Association of Physicists in Medicine(AAPM) phantom was applied to each algorithm and the exposure condition of 120 kVp, 250 mAs, and then the CT number and noise were measured. The MTF curved line of the high-contrast resolution was calculated with Point Spread Function(PSF) by using the analysis program by Philips, resulting in 0.5 MTF, 0.1 MTF and 0.02 MTF respectively. The low-contrast resolution was calculated with CNR and the uniformity was measured to each algorithm. Since the measurement value for the uniformity of the equipment was below ${\pm}$ 5 HU, which is the criterion figure, it was found to belong to the normal range. As the algorithm got closer from soft to edge, the standard deviation of CT number increased, which indicates that the noise increased as well. As for MTF, 0.5 MTF, 0.1 MTF and 0.02 MTF were all sharp algorithms, and as the algorithm got closer from soft to edge, it was possible to distinguish more clearly with the naked eye. On the other hand, CNR gradually decreased, because the difference between the contrast hole CT number and the acrylic CT number was the same while the noise of hole increased.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.313-318
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• 1998

Electro-Optical Camera(EOC) is the main payload of Korea Multi-Purpose SATellite(KOMPSAT) with the mission of cartography to build up a digital map of Korean territory including Digital Terrain Elevation Map(DTEM). This instrument which comprises EOC Sensor Assembly and EOC Electronics Assembly produces the panchromatic images of 6.6 m GSD with a swath wider than 17 km by push-broom scanning and spacecraft body pointing in a visible range of wavelength, 510 ~ 730 nm. The high resolution panchromatic image is to be collected for 2 minutes during 98 minutes of orbit cycle covering about 800 km along ground track, over the mission lifetime of 3 years with the functions of programmable rain/offset and on-board image data storage. The image of 8 bit digitization, which is collected by a full reflective type F8.3 triplet without obscuration, is to be transmitted to Ground Station at a rate less than 25 Mbps. EOC was elaborated to have the performance which meets or surpasses its requirements of design phase. The spectral response the modulation transfer function, and the uniformity of all the 2592 pixel of CCD of EOC are illustrated as they were measured for the convenience of end-user. The spectral response was measured with respect to each gain setup of EOC and this is expected to give the capability of generating more accurate panchromatic image to the EOC data users. The modulation transfer function of EOC was measured as greater than 16% at Nyquist frequency over the entire field of view which exceeds its requirement of larger than 10%, The uniformity that shows the relative response of each pixel of CCD was measured at every pixel of the Focal Plane Array of EOC and is illustrated for the data processing.

• 한국정보통신학회논문지
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• 제23권7호
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• pp.771-778
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• 2019

기존 단일 조도센서를 이용한 조도검출 방식은 좁은 FOV (Field of View) 특성 상 측정 위치에 따라 검출 조도의 균일도가 저하된다. 다수개의 조도센서를 통해 평균 조도값을 검출하는 방법은 복잡도 증가 및 계산과정에서 오류가 증가하는 문제점을 가지고 있다. 본 논문에서는 넓은 FOV를 가지는 하나의 이미지센서를 기반으로 한 조도검출 방법을 제안하였으며, 제안된 방법은 기존 조도센서가 가지는 시스템 복잡도, 오류 증가 등의 문제점이 해결 가능하다. 실내 환경에서의 성능평가 결과는 색차조도계 (CL-200A)를 이용한 기준값 대비 조도센서가 1개인 경우 평균 12%, 조도센서가 5개인 경우 평균 10.7%, 이미지센서의 경우 평균 6.2% 차이가 발생하는 것을 확인하였으며, 이를 통해 이미지센서를 기반으로 한 제안된 검출방법은 균일성이 향상된 공간조도를 간단하고 정확하게 검출할 수 있음을 확인하였다.

• 대한원격탐사학회지
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• 제31권4호
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• pp.337-346
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• 2015

Water body extraction based on backscatter information is an essential process to analyze floodaffected areas from Synthetic Aperture Radar (SAR) image. Water body in SAR image tends to have low backscatter values due to homogeneous surface of water, while non-water body has higher backscatter values than water body. Non-water body, however, may also have low backscatter values in high resolution SAR image such as Kompsat-5 image, depending on surface characteristic of the ground. The objective of this paper is to present a method to increase backscatter contrast between water body and non-water body and also to remove efficiently misclassified pixels beyond true water body area. We create an entropy image using a Gray Level Co-occurrence Matrix (GLCM) and classify the entropy image into water body and non-water body pixels by thresholding of the entropy image. In order to reduce the effect of threshold value, we also propose Water Body Texture Index (WBTI), which measures simultaneously the occurrence of repeated water body pixel pair and the uniformity of water body in the binary entropy image. The proposed method produced high overall accuracy of 99.00% and Kappa coefficient of 90.38% in water body extraction using Kompsat-5 image. The accuracy analysis indicates that the proposed WBTI method is less affected by the choice of threshold value and successfully maintains high overall accuracy and Kappa coefficient in wide threshold range.

• 한국콘텐츠학회논문지
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• 제16권8호
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• pp.592-600
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• 2016

AAPM CT 성능 평가용 표준 팬텀을 이용한 특수의료장비 품질관리 검사 시, 평가자의 주관적인 평가로 인한 오류를 최소화 하고자 전산화된 평가 프로그램을 이용하여 유용성을 평가하고자 한다. 평가 팬텀으로 AAPM CT Performance Phantom을 사용하였고, 기본 촬영 조건은 품질관리검사와 동일하며, 평가프로그램으로 IMAGE J를 사용하였다. 정량적인 평가로 CT 감약계수와 노이즈측정, 균일도측정, 슬라이스 두께 측정, 대조도 분해능 측정, 공간 분해능 측정의 팬텀 영상을 평가프로그램을 이용하여 영상처리를 한 후 자동추출 된 결과로 평가 하였으며, CT 감약계수, 노이즈, 균일도 측정은 영상처리를 한 영상의 표준편차가 작아 더 균일하다고 평가하였고, 슬라이스 두께 측정은 팬텀영상의 측정값과의 비율 차로 인해 평가에 어려움이 있었다. 대조도 분해능은 원통형의 지름을 6회 측정하여 지름의 평균값과 표준편차를 구해 원의 형태를 평가하였으며, 공간 분해능은 합격기준을 포함하는 원의 그룹을 자동 추출한 결과 원의 개수를 모두 추출한 결과로 나타났다. 정성적인 평가로 원본영상과 영상 처리한 영상을 육안적으로 비교 평가 하였는데 영상처리 된 영상이 우수한 결과를 나타내었다. 위의 결과 등을 바탕으로 평가자의 주관적인 판단의 오류를 최소화하기 위해서는 정량적인 평가와 정성적인 평가가 함께 이루어져야 하고 전산화된 평가프로그램을 활용한다면 보다 더 효율적인 평가가 이루어 질 것이라고 사료된다.