• 한국기계가공학회지
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• 제11권5호
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• pp.142-147
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• 2012

Machining tool conditions directly affect to quality of product and productivity of manufacturing. Many researches performed for tool condition monitoring in machining process to improve quality and productivity. Conventional methods use characteristics of signal for cutting force, motor current consumption, vibration of machine tools and machining sound. Recently, diameter of machining tool is become smaller for minimizing of mechanical parts. Tool condition monitoring using conventional methods are relatively difficult because micro machining using small diameter tool has low machining load and high cutting speed. These days, the direct monitoring for tool conditions using vision system is performed actively. But, vision system is affected by external conditions such as back ground of image and illumination. In this study, minimizing technology of external conditions using distribution analysis of image data are developed in micro machining using small diameter drill and tap. The image data is gathered from vision system. Several sets of experiment results are performed to verify the characteristics of the proposed machining technology.

• Journal of Microbiology
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• 제34권4호
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• pp.300-304
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• 1996

To define the effects of zooplankton and phytoplankton to bacteria, bacterial numbers, frequency of dividing cells (FDC) and size distribution were performed with image analysis in the surface layer of Lake Soyang. In August 1992, when Anabaena was blooming, the bacterial number increased at daytime. Bacterial numbers and FDC value had a negative correlation (r = 0.83, P < 0.01). Bacterial size spectrums were dynamically changed during the day and night, especially the small bacteria less than $0.5\;{\mu}m^3$. Meanwhile, in October, after the bloom, the bacterial number was only one third of that in August, even though the FDC was higher than that in August. The bacterial numbers of small size class dropped at 13:00. But the size spectrums were relatively constant during the night time. These results suggest that the bacterial growth was tightly coupled with phytoplankton during Anabaena bloom. And after the bloom, the bacterial number was controlled grazing activity of zooplankton at daytime.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.184-187
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• 1997

Small PACS based on a personal computer or CR has initially been designed to improve the performance of cost-effective PACS implementation. In that system, Wavelet compression scheme is newly adopted to store images hierarchically to storage unit, and retrieve and display images progressively or display workstation. In this compression method, image is decomposed into subclasses of image by wavelet transform, and then the subclasses of image are vector quantized using a multiresolution codebook.

• 대한원격탐사학회지
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• 제2권1호
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• pp.13-21
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• 1986

The study was emphasized on the applicability of Landsat data for vegetation classification of touch as small natural swamp areas Yujeon natural swamp in Haman-gun through image processing system. The image processing technique which was applied is maximum likelihood method. The classified types on the Landsat image are water, nelumbo, grass, agricultural field and conifer. The computer processed classification was compared the existed data for evaluating the result, but there are some difficulties on the exact comparison between them because of discordance of the temporal resolution. The result, anyhow, is quite remarkable that Landsat MSS data can be used for the quantitative estimates of vegetation type classification in such small area.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2012년도 춘계학술발표대회논문집
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• pp.40-42
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• 2012

Colorization is a method using computer to add color to a black and white image automatically. The input is a grayscale image and some representative pixels (RPs). The RPs contain the color information for the image, and it indicates each region's color information. Colorization-based coding is a novel way for lossy image compression, it decodes a color image to get grayscale image and extracts RPs from the image. Because RPs decides the region's color and we also want small data size for image compression, form this viewpoint the paper proposes a way to get better and fewer RPs based on watershed segmentation. According to the segmentation result we also improve the original chrominance blending colorization method to save decode time and get better reconstruct image.

• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.154-159
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• 2019

Undesirable negative image is occurred in photographs taken across partial reflections such as glass window and electronic display. Efficient removing reflections given a single image are in the spotlight in recent researches. This paper discusses and evaluates two published image reflection removal algorithms, and compares the performance of time and quality of those methods with a common dataset. As benchmarking test cases are presented, we propose to modify one of the methods to reduce the run-time with small effects on the similar image quality.

• 한국통신학회논문지
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• 제35권1C호
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• pp.8-16
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• 2010

본 논문은 적외선 영상 시퀀스 (infrared image sequences)에서 시간적 프로파일 (temporal profile)을 기반으로 한 시간적 화소 (temporal pixel)들의 외적 (cross product)을 사용한 새로운 소형 표적 검출 방법을 제안한다. 소형 표적 및 그 주변배경은 시간적 특성이 서로 다르므로, 시간적 프로파일에서 화소들의 외적을 사용한 가설검증을 통하여 표적 화소 및 배경화소를 구분하고, 그 결과를 기반으로 시간적 배경 (temporal background)을 예측한다. 소형 표적은 원 시간적 프로파일과 예측된 시간적 배경 프로파일의 차에 의해 검출한다. 기존 방법과 제안한 방법의 성능 비교를 위하여, ROC (receiver operating characteristics) 곡선을 실험에서 사용하였다. 실험결과에서 제안된 방법이 기존방법들보다 오경보율 (false alarm rate)이 낮고, 표적 및 배경에 대한 향상된 식별력을 가짐을 확인하였다.

• 한국방사선학회논문지
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• 제16권3호
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• pp.249-255
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• 2022

소동물용 양전자방출단층촬영기기는 매우 작은 장기를 영상화하기 위해 매우 높은 공간분해능을 지닌다. 우수한 공간분해능을 획득하기 위해서는 매우 작은 섬광 픽셀을 사용하여 시스템을 구성해야 한다. 매우 작은 섬광 픽셀을 사용하여 검출기를 구성할 경우 광센서 픽셀에 따라 적용가능한 배열의 크기가 달라진다. 이전 연구에서 광센서 크기에 따른 최대의 섬광 픽셀 배열을 찾는 연구를 수행하였다. 본 연구에서는 더 확장된 섬광 픽셀 배열을 사용하여 검출기를 구성하기 위해 광가이드를 적용한 검출기를 설계하여 모든 섬광 픽셀들이 영상화되는 최대의 배열을 찾고자 한다. 섬광체로 이루어진 검출기의 시뮬레이션이 가능한 DETECT2000을 사용하여 검출기를 설계하였다. 11 × 11 섬광 픽셀 배열에서부터 16 × 16 배열까지 검출기를 구성하여 시뮬레이션을 수행하였다. 섬광 픽셀에서 발생된 빛을 광센서로 수집하여 평면 영상을 획득한 후 영상의 분석을 통해 겹침이 발생하지 않는 최대의 배열을 찾았다. 그 결과 겹침이 발생하지 않고 모든 섬광 픽셀들이 구분 가능한 최대의 배열은 15 × 15 배열이었다.

• 한국멀티미디어학회논문지
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• 제24권3호
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• pp.373-381
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• 2021

In this paper, we propose a classification model based on convolutional neural network(CNN) for predicting 2-year recurrence in non-small cell lung cancer(NSCLC) patients using preoperative chest CT images. Based on the region of interest(ROI) defined as the tumor internal and external area, the input images consist of an intratumoral patch, a peritumoral patch and a peritumoral texture patch focusing on the texture information of the peritumoral patch. Each patch is trained through AlexNet pretrained on ImageNet to explore the usefulness and performance of various patches. Additionally, ensemble learning of network trained with each patch analyzes the performance of different patch combination. Compared with all results, the ensemble model with intratumoral and peritumoral patches achieved the best performance (ACC=98.28%, Sensitivity=100%, NPV=100%).

• 대한의용생체공학회:의공학회지
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• 제26권1호
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• pp.43-47
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• 2005

We have developed a small bore x-ray CT for small animal imaging with a linear x-ray detector array and small-scale slip rings. The linear x-ray detector array consists of 1024 elements of 400□m×400□m with a gadolinium oxysulfide (GOS) scintillator on top of them. To avoid use of expensive large diameter slip rings for projection data transmission from the X­ray detector to the image reconstruction system, we used the wireless LAN technology. The projection data are temporally stored in the data acquisition system residing on the rotating gantry during the scan and they are transmitted to the image reconstruction system after the scan. With the wireless LAN technology, we only needed to use small-scale slip rings to deliver the AC electric power to the X-ray generator and the power supply on the rotating gantry. The performances of the small animal CT system, such as SNR, contrast, and spatial resolution, have been evaluated through experiments using various phantoms. It has been experimentally found that the SNR is almost linearly proportional to the tube current and tube voltage, and the minimum resolvable contrast is less than 30 CT numbers at 40kVp/3.0㎃. The spatial resolution of the small animal CT system has been found to be about 0.9Ip/㎜. Postmortem images of a piglet is also presented.