• 한국정밀공학회지
• /
• 제21권11호
• /
• pp.200-208
• /
• 2004

In ultrasonic bone densitometry, the positioning of measurement site is decisive in precision and reproducibility. In this study, automatic Region of Interest (ROI) detection algorithm is suggested and adopted the method using the local minimum value by ultrasonic image. The preprocess before the local minimum method extracts out the bone area and calculates the geometrical information of bone. The developed ROI detection algorithm was applied to the clinical test for the subject of 305 female patients in the range of 22-88 years old. As the results, the accuracy of the algorithm was shown to be 98.3％. It was also found that bone density parameter was significantly correlated with age(r=0.85, p<0.0001).

• 한국컴퓨터정보학회논문지
• /
• 제11권5호
• /
• pp.1-8
• /
• 2006

효율적인 네트워크 운용을 위해 트레픽를 측정하는 일은 중요하다. 흔히 용량(capacity)은 트레픽 부하가 없을 때 경로가 제공할 수 있는 최대처리량 또는 경로상의 모든 링크 간의 최소 전송율로서 정의된다. Pathrate는 현재 가장 널리 사용되는 네트워크 용량 측정 도구 중의 하나로써 네트워크의 일시적인 부하에 관계없이 정확한 측정을 할 수 있고 수년간의 개발과 보완으로 성능도 안정되어 있다. Pathrate에서의 Local Mode 검출에는 통계적 방법이 사용되는데 본 논문에서는 ASH(Averaged Shifted Histogram)을 이용한 Local Mode 검출 알고리즘을 제시하고, 구현을 통해 기존의 방법보다 더 나은 결과를 얻었음을 보였다.

• Journal of the Korean Physical Society
• /
• 제73권11호
• /
• pp.1644-1649
• /
• 2018

Aiming at infrared thermal images with different buried depth defects, we study a variety of image segmentation algorithms based on the threshold to develop global search ability and the ability to find the defect area accurately. Firstly, the iterative thresholding method, the maximum entropy method, the minimum error method, the Ostu method and the minimum skewness method are applied to image segmentation of the same infrared thermal image. The study shows that the maximum entropy method and the minimum error method have strong global search capability and can simultaneously extract defects at different depths. However none of these five methods can accurately calculate the defect area at different depths. In order to solve this problem, we put forward a strategy of "divide and conquer". The infrared thermal image is divided into several local thermal maps, with each map containing only one defect, and the defect area is calculated after local image processing of the different buried defects one by one. The results show that, under the "divide and conquer" strategy, the iterative threshold method and the Ostu method have the advantage of high precision and can accurately extract the area of different defects at different depths, with an error of less than 5%.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제5권4호
• /
• pp.649-664
• /
• 2011

Cooperative spectrum sensing (CSS) with decision fusion is considered as a key technology for tackling the challenges caused by fading/shadowing effects and noise uncertainty in spectrum sensing in cognitive radio. However, most existing solutions assume an error-free decision transmission, which is obviously not the case in realistic scenarios. This paper extends the general decision-fusion-based CSS scheme by considering the fading/shadowing effects and noise corruption in the common control channels. With this more practical model, the fusion centre first estimates the local decisions using a binary minimum error probability detector, and then combines them to get the final result. Theoretical analysis and simulation of this CSS scheme are performed over typical channels, which suggest some performance deterioration compared with the pure case that assumes an error-free decision transmission. Furthermore, the fusion strategy optimization in the proposed cooperation model is also investigated using the Bayesian criteria. The numerical results show that the total error rate of noisy CSS is higher than that of the pure case, and the optimal values of fusion parameter in the counting rule under both cases decrease as the local detection threshold increases.

• 전기전자학회논문지
• /
• 제19권2호
• /
• pp.244-253
• /
• 2015

본 논문은 비의도 움직임 검출 및 적응적 움직임 완화 필터를 이용한 동영상 안정화 기법을 제안한다. 제안된 기법은 비의도 움직임 검출 단계와 검출된 비의도 움직임을 완화 필터링하는 단계로 구성된다. 움직임 완화 과정에 요구되는 속성들을 활용하기 위하여 누적 전역 움직임 매개변수들로 구성된 집합의 국부 최대값과 국부 최소값을 정의한다. 국부 정보를 사용하여 비의도 움직임 검출에 필요한 제약조건을 정의하며, 제약조건들을 기반으로 하여 알파-조정 평균 필터의 알파 값을 결정하여 재구성된 동영상의 움직임 완화 정도를 제어한다. 실험 결과를 통해 제안된 방식의 성능 우수성을 입증하였다.

• 한국정보통신학회논문지
• /
• 제14권9호
• /
• pp.1972-1978
• /
• 2010

AAM(Active Appearance Model)은 변형 가능한 형태의 검출에 가장 효과 적인 방법의 하나이며, 수학적으로 최적화 문제이다. 비용함수는 최소자승 함수이어서 볼록 함수이나, 탐색 공간이 볼록공간이 아니므로 국소 최소값이 전역 최소값인 것으로 보장 되지 않는다. 즉 초기값이 전역 최소값 근방에서 출발하지 않으면, 지역 최소값에 수렴하여 정확한 얼굴 윤곽 검출이 어려워진다. 본 논문에서는 연속적인 입력영상에 SIFT(Scale Invariant Feature Transform)와 유전자 알고리즘을 사용하여 눈동자를 검출하고 AAM 모델의 초기화 정보로 사용함으로써 조명과 배경에 강인한 AAM 기반의 얼굴 정합 방법을 제안한다. 실험을 통하여 제안한 AAM 기반 얼굴 정합 방법이 자세, 얼굴 배경 등에 대해 기존의 AAM 기반 얼굴 정합 방법보다 더 강인한 것으로 확인 되었다.

• 한국정보통신학회논문지
• /
• 제19권12호
• /
• pp.2975-2980
• /
• 2015

에지 검출은 대부분의 영상 처리에서 중요한 전처리 과정으로서, 물체의 크기, 위치, 방향 등을 포함한 여러 특징 정보를 검출하는 영상 처리 기법이다. 이러한 에지 검출은 국내외 여러 분야에서 발전되고 있다. 널리 알려진 기존의 에지 검출 방법에는 고정된 가중치 값으로 구성된 마스크를 이용한 Sobel, Prewitt, Roberts, LoG 등이 있다. 이러한 기존의 에지 검출 방법들은 가중치가 고정된 마스크를 영상에 적용하기 때문에 다소 에지 검출 특성이 미흡하게 나타난다. 따라서 본 연구에서는 이러한 문제점을 보완하기 위해, 그레이 레벨 변환 함수를 적용한 후, 국부 마스크로부터 추정 마스크를 구하여 그 마스크의 최대값 및 최소값을 이용하여 에지를 구하는 알고리즘을 제안하였다. 그리고 제안한 알고리즘의 성능을 평가하기 위해, 기존의 Sobel, Roberts, Prewitt, LoG 에지 검출 방법들과 비교하였다.

• 한국한의학연구원논문집
• /
• 제14권3호
• /
• pp.89-95
• /
• 2008

A tongue shows physiological and clinicopathological changes of inner organs. Visual inspection of a tongue is not only convenient but also non-invasive. To develop an automat ic tongue diagnosis system for an objective and standardized diagnosis, the separation of the tongue are a from a facial image and the detection of coatings, spots and cracks are inevitable but difficult since the colors of a tongue, lips, and skin in a mouth as well as those of tongue furs and body are similar. The propose d method includes preprocessing with down-sampling and edge enhancement, over-segmentation, detecting positions with a local minimum over shading from the structure of a tongue, and correcting local minima or detecting edge with color difference. The proposed method produces the region of a segmented tongue, and then decomposes the color components of the region into hue, saturation and brightness, resulting in classifying the regions of tongue furs(coatings) into kinds of coatings and substance and segmenting them. Spots are detected by using local maxima and the variation of saturation, and cracks are searched by using local minima and the directivity of dark areas in brightness. The results illustrate the segmented region with effective information, excluding a non-tongue region and also give us accurate discrimination of coatings and the precise detection of spots and cracks. It can be used to make an objective and standardized diagnosis for an u-Healthcare system as well as a home care system.

• 전기학회논문지
• /
• 제56권11호
• /
• pp.2051-2057
• /
• 2007

In Oriental medicine, the status of a tongue is the important indicator to diagnose one's health like physiological and clinicopathological changes of inner parts of the body. The method of tongue diagnosis is not only convenient but also non-invasive and widely used in Oriental medicine. However, tongue diagnosis is affected by examination circumstances a lot like a light source, patient's posture and doctor's condition. To develop an automatic tongue diagnosis system for an objective and standardized diagnosis, segmenting a tongue is inevitable but difficult since the colors of a tongue, lips and skin in a mouth are similar. The proposed method includes preprocessing, graph-based over-segmentation, detecting positions with a local minimum over shading, detecting edge with color difference and estimating edge geometry from the probable structure of a tongue, where preprocessing performs down-sampling to reduce computation time, histogram equalization and edge enhancement. A tongue was segmented from a face image with a tongue from a digital tongue diagnosis system by the proposed method. According to three oriental medical doctors' evaluation, it produced the segmented region to include effective information and exclude a non-tongue region. It can be used to make an objective and standardized diagnosis.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제49권9호
• /
• pp.504-511
• /
• 2000

The reliability of system is to become a important concern in developed industry. The controller based on the reliability is so important position. PPC(Plant Protection Controller) is for plant protection and human life by fault detection and control action against the transient condition of plant. The protection system of the nuclear reactor and chemical reactor are representative of PPC. This paper presents analysis of PPC relaibility formal problem statement of optimal redundancy based on the reliability for PPC. And the problem is optimized by genetic algorithm, The genetic algorithms is useful algorithm in case of large searching complex gradient existence local minimum. The genetic algorithms is useful algorithm is case of large searching complex gradient existence local minimum. The ability and effectiveness of the proposed optimization is demonstrated by the target reliability of one channel. PPC. using the failure rate based on the MIL-HDBK-217