• 한국멀티미디어학회논문지
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• 제2권2호
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• pp.155-165
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• 1999

암호화(encryption)된 정보는 랜멈한 형태이기 때문에 공격자에 의해 기밀 정보가 누출될 위협이 있다. 한편, 화상 심충암호(image steganography)는 화상 내에 기밀 정보를 몰래 숨겨서 전송하는 것으로 제3자는 기밀 정보의 폰재 사실을 알 수 없기 때문에 공격의 위협을 줄일 수 있게 된다. 화상 심충암호에서 기밀 정보는 잡음의 형태로 화상의 화소값을 변경하여 숨기게 된다 이와 같이 농담화상(gray image)에 기밀 정보 를 숨기는 경우에는 잡음으로 인한 화질 열화를 초래한다. 따라서, 농담화상에 디더링(dithering)을 수행하는 과정에서 기밀 정보를 숨기는 방식이 고안되었다 오차 확산법을 이용한 기존의 방식은 고정된 간격마다 기밀 정보를 합성함에 따라 일정한 패턴이 생기는 문제점이 있다 이러한 문제를 해결하고 기존의 방법을 향상시키기 위하여 본 논문에서는 런 길이(run length)를 이용하여 변환점에 기밀 정보를 합성하거나 원래의 디더값과 오차가 가장 적은 위치에 기밀 정보를 합성하는 새로운 방법을 제안하고, 그 성능을 컴퓨터 시율레이 션올 통하여 평가하였다.

• 한국정보통신학회논문지
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• 제6권8호
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• pp.1358-1364
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• 2002

현재 방송 및 인터넷분야에서는 멀티미디어 정보가 급격히 증가하고 있다. 본 논문에서는 멀티미디어 정보 중에서 정지영상 검색을 위해 사용자가 질의(query)를 원하는 물체영역을 선택한 후 유사물체를 영상 데이터베이스 내에서 검색할 수 있는 내용기반 영상검색 시스템을 구현하였다. 질의영상으로부터 우선 컬러특성을 추출하기 위해 제안한 방법으로 색상을 HSV 변환한 후 히스토그램을 구해 데이터베이스영상과 히스토그램 인터섹션을 통해 유사치를 구한다 또한 질의영상을 그레이영상으로도 변환시켜 웨블릿 변환한 후 밴디드 오토코릴로그램과 GLCM을 통해 공간적 그레이분포와 질감특성을 추출하여 유사치를 구한다. 그리고 2개의 유사치를 더하여 최종 유사도를 결정하는데 이때 각 유사치에 가중치를 적용하였다. 질의영상으로부터 컬러영상 특성뿐만 아니라 그레이영상 특성도 파악하여 단점을 보완하였고 실험결과에서도 소환성(recall) 및 정확성(precision)이 향상됨을 볼 수 있었다. 또한 가중치를 적용함으로써 검색효율이 개선되었다.

• Advances in Traditional Medicine
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• 제7권5호
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• pp.556-563
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• 2008

Peripheral nerve injuries are a commonly encountered clinical problem and often result in a chronic pain and severe functional deficits. The expression of c-Fos is sometimes used as a marker of increased neuronal activity. We have prepared the aqueous extract of amygdalin from Armeniacae semen for pain control. In the present study, we investigated the effects of amygdalin on the recovery rate of the locomotor function and on the expression of c-Fos in the ventrolateral periaqueductal gray (vlPAG) region following sciatic crushed nerve injury in rats. Walking track analysis for the evaluation of functional recovery and immunohistochemistry for the c-Fos expression were used in this study. In the present results, characteristic gait change with dropping of the sciatic function index (SFI) was observed and c-Fos expression in the vlPAG was suppressed following sciatic crushed nerve injury in rats. Amygdalin enhanced SFI value and restored c-Fos expression in the vlPAG to the control value. The present our study indicated that amygdalin activates neurons in the vlPAG, and it facilitates functional recovery following peripheral nerve injury.

• 방사선산업학회지
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• 제12권4호
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• pp.267-276
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• 2018

A Hoffman 3D Brain Phantom was used to evaluate two PET/CT scanners, BIO_40 and D_690, according to the radiation dose of CT (low, medium and high) at a fixed kilo-voltage-peak (kVp) with the tube current(mA) varied in 17~20 stages(Bio_40 PET/CT scanner: the tube voltage was fixed to 120 kVp, the effective tube current(mAs) was increased from 33 mAs to 190 mAs in 10 mAs increments, D_690 PET/CT scanner: the tube voltage was fixed to 140 kVp, tube current(mA) was increased from 10 mAs to 200 mAs in 10 mAs increments). After obtaining the PET image, an attenuation correction was conducted based on the attenuation map, which led to an analysis of the difference in the image. First, the ratio of white to gray matter for each scanner was examined by comparing the coefficient of variation (CV) depending on the average ratio. In addition, a blind test was carried out to evaluate the image. According to the study results, the BIO_40 and D_690 scanners showed a <1% change in CV value due to the tube current conversion. The change in the coefficients of white and gray matter showed that the Z value was negative for both scanners, indicating that the coefficient of gray matter was higher than that of white matter. Moreover, no difference was observed when the images were compared in a blind test.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.438-444
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• 2007

Bacillus licheniformis N1 is a biological control agent to control gray mold diseases caused by Botrytis cinerea. Various formulations of B. licheniformis N1 were generated and evaluated for the activity to control strawberry gray mold. The wettable powder type formulation N1E was selected in pot experiments with remarkable disease control activity on both strawberry leaves and flowers. The N1E formulation contained 400 g of com starch, 50 ml of olive oil, and 50 g of sucrose per a liter of bacterial fermentation culture. Optimum dilution of N1E to appropriately control the strawberry gray mold appeared to be 100-fold dilution in plastic house artificial infection experiments. The significant reduction of symptom development in the senescent leaves was apparent by the treatment of N1E at 100-fold dilution when N1E was applied before Bo. cinerea inoculation, but not after the inoculation. Both artificial infection experiments in a plastic house and natural infection experiments in the farm plastic house under production conditions revealed that the disease severity of gray mold on strawberry leaves and flowers was significantly reduced by N1E treatment. The disease control value of N1E on strawberry leaves was 81% under production conditions, as compared with the 61.5% conferred by a chemical fungicide, iprodione. This study suggests that our previously generated formulation of B. licheniformis N1 will be effective to control strawberry gray mold by its preventive activity.

• 한국멀티미디어학회논문지
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• 제10권4호
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• pp.432-440
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• 2007

본 논문에서는 복잡한 배경을 가지는 전방 관측 열상(FLIR; forward looking infrared) 영상에서의 소형 표적 탐지 기법을 제안하였다. 제안한 기법에서는 먼저 이전 프레임과 현재 프레임의 차를 구하여 표적의 움직임 정보를 획득할 뿐만 아니라 시간적으로 발생하는 배경 잡음을 제거한다. 이때 먼 거리에서 다가오는 표적이나 속도가 느린 표적의 경우 차 영상 내에서의 표적의 움직임 정보는 매우 작은 명암도 값을 가진다. 이런 작은 명암도 값을 두드러지게 하여 표적 탐지를 용이하게 하기 위하여 프레임 차 영상에 국부 감마교정을 행한다. 이렇게 표적이 개선된 영상에서 국부적인 통계적인 특성을 이용하여 탐지 지표를 계산한 후 가장 낮은 탐지 지표 값을 탐지하고자하는 표적으로 선정한다. 실험을 통하여 제안한 기법이 표적의 탐지성능이 기존의 탐지기법보다 우수하였음을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제11권2호
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• pp.217-226
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• 1990

This paper presents a new algorithm that extracted lung region in X-ray and enhanced the region. With a lung region that was extracted by histogram threshold value, it was diffi cult to detect perfect lung boundary. Therefore we presented perfect lung boundary detection method using apex detection and apex region restoration. Also, by applying modified equalization algorithm and presented function to inside of lung region, we want to give help to automatic diagnosis In X-ray chest image. Presented main line trace algorithm gave good result in detection of lung boundary And, as apex detection method using lung row and column gray level average value found more correct place of lung than the rpethod of prior algorithm, we succeeded perfect lung region detection, Also, presented function that had lung region's gray level distribution characteristic was very effective to image enhancement.

• 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.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권3호
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• pp.148-155
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• 2005

A seam-line determination algorithm is proposed to determine image border-line in mosaicing using the transformation of gray value differences and dynamic programming. Since visually good border-line is the one along which pixel differences are as small as possible, it can be determined in association with an optimal path finding algorithm. A well-known effective optimal path finding algorithm is the Dynamic Programming (DP). Direct application of the dynamic programming to the seam-line determination causes the distance effect, in which seam-line is affected by its length as well as the gray value difference. In this paper, an adaptive cost transform algorithm with which the distance effect is suppressed is proposed in order to utilize the dynamic programming on the transformed pixel difference space. Also, a figure of merit which is the summation of fixed number of the biggest pixel difference on the seam-line (SFBPD) is suggested as an evaluation measure of seamlines. The performance of the proposed algorithm has been tested in both quantitively and visually on various kinds of images.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제3권1호
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• pp.13-17
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• 2003

A continuous solution of the Dirichlet boundary value problem for the heat equation $u_t$＝$a2u_{xx}$ using a fuzzy system is described. We first apply the Crank-Nicolson method to obtain a discrete solution at the grid points for the heat equation. Then we find a continuous function to represent approximately the discrete values at the grid points in the form of a bicubic spline function (equation omitted) that can in turn be represented exactly by a fuzzy system. We show that the computed values at non-grid points using the bicubic spline function is much smaller than the ones obtained by linear interpolations of the values at the grid points. We also show that the fuzzy rule table in the fuzzy system representation of the bicubic spline function can be viewed as a gray scale image. Hence, the fuzzy rules provide a visual representation of the functions of two variables where the contours of different levels for the function are shown in different gray scale levels