• 전자공학회논문지
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• 제52권11호
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• pp.137-146
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• 2015

본 논문에서는 명암과 움직임에 따른 다양한 특징점들을 이용하여 포트홀 검출하는 방법을 제안한다. 포트홀 검출 방법은 명암과 움직임에 따라 각각 분할되는 단계와 상호 특징점들의 값에 따라 검출이 결정되는 단계로 이루어진다. 명암을 이용한 분할은 히스토그램을 이용한 이진화 방법을 사용하여 포트홀과 주변 영역을 구분한다. 움직임을 이용한 분할은 먼저 움직임의 변화가 있는 영역을 구분하기 위하여 high pass filtering을 한 후 standard deviation 값을 얻는다. 그리고 도로 촬영 각도, 높이, 속도 등에 따른 움직임 크기를 조정하기 위하여 regression값으로 나눈다. 히스토그램 기반 이진화를 이용하여 이진 영상으로 만든다. 포트홀을 검출하는 결정에서는 후보 영역과 배경 영역과의 특징점들의 비교를 통해서 후보 영역이 포트홀 여부를 판단한다. 실험 결과, 제안하는 방법이 기존 포트홀 검출 방법 보다 향상된 결과를 보이고 포트홀과 유사한 형태들과 구분하는 향상된 결과를 보인다.

• 센서학회지
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• 제26권3호
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• pp.186-191
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• 2017

In this study, we investigated the simultaneous detection properties of organic vapor, pressure difference, and magnetic field using a single rugate-structured free-standing porous silicon (RFPS) thin film. Both the wavelength and the intensity of the rugate peaks were changed in the reflectivity spectrum measured at the thin film surface while the organic vapor was exposed to the RFPS thin film. However, when the pressure difference and the magnetic field were exposed to the film, only the rugate peak intensity was changed. Therefore, it is possible to distinguish whether or not the organic vapor is detected by simultaneously changing the rugate peak wavelength and intensity. In addition, a method of distinguishing between the pressure difference and the magnetic field detection signal has been derived by rapidly modulating the direction of the magnetic field. This study shows that it is possible to simultaneously detect and distinguish various objects using a single RFPS thin film, and it is found that porous silicon can be utilized as a sensor sufficiently.

• 대한임베디드공학회논문지
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• 제11권5호
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• pp.313-323
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• 2016

With the development of autonomous vehicle, there has been active research on advanced driver assistance system for road marking detection using vision sensor and 3D Laser scanner. However, vision sensor has the weak points that detection is difficult in situations involving severe illumination variance, such as at night, inside a tunnel or in a shaded area; and that processing time is long because of a large amount of data from both vision sensor and 3D Laser scanner. Accordingly, this paper proposes a road marking detection and classification method using single 2D Laser scanner. This method road marking detection and classification based on accumulation distance data and intensity data acquired through 2D Laser scanner. Experiments using a real autonomous vehicle in a real environment showed that calculation time decreased in comparison with 3D Laser scanner-based method, thus demonstrating the possibility of road marking type classification using single 2D Laser scanner.

• 한국멀티미디어학회논문지
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• 제19권4호
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• pp.736-746
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• 2016

In this paper, we propose an automatic prostate cancer detection method using position, signal intensity and texture feature based on SVM in multi-parametric MR images. First, to align the prostate on DWI and ADC map to T2wMR, the transformation parameters of DWI are estimated by normalized mutual information-based rigid registration. Then, to normalize the signal intensity range among inter-patient images, histogram stretching is performed. Second, to detect prostate cancer areas in T2wMR, SVM classification with position, signal intensity and texture features was performed on T2wMR, DWI and ADC map. Our feature classification using multi-parametric MR imaging can improve the prostate cancer detection rate on T2wMR.

• 한국콘텐츠학회논문지
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• 제6권12호
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• pp.21-28
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• 2006

형판 정합 기반의 얼굴 검출 시스템에서 획득된 이미지에 대한 명암 정규화 및 영상 보정을 위해 보통 히스토그램 평활화 등을 사용한다. 이 방법은 조명 변화에 의해 발생한 이미지의 부분 명암 왜곡에는 효과적이지 못하다는 것이 알려져 있다. 본 논문에서는 다양한 방향의 조명에 의한 명암 왜곡을 효과적으로 보정하는 전처리 기법을 제시한다. 이 기법은 얼굴의 좌우대칭성을 이용한 좌우대칭 평균화와 단순회귀분석을 이용한 세로 방향 명암 보정을 결합한 것이다. 실험 결과 이 기법은 기존의 방식보다 높은 검출성능을 보일 뿐만 아니라 얼굴의 후보 개수도 현저하게 감소하는 것으로 나타났다.

• 센서학회지
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• 제26권6호
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• pp.402-407
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• 2017

Characteristics of various material surface plasmon resonance (SPR) chips were investigated in angular interrogation mode and intensity interrogation mode. Among five metals, silver (Ag), gold (Au), copper (Cu), chromium (Cr) and titanium (Ti), three metals, Ag, Au and Cu were paid attention to since their characteristics can be easily analyzed in angular interrogation mode by investigating the change of their reflectance curves according to refractive index change from 1.331 to 1.335. Most of SPR chips with various configurations showed the similar property in angular interrogation mode. The application of the SPR chip made of Ag, Au and Cu or their combinations depends on their reflectance properties. In intensity interrogation mode, the operation range may be limited since the variation of the intensity was not linearly related to refractive index change ranging from 1.331 to 1.335. However, the SPR chip containing high ratio of Ag may be applicable to high sensitive detection due to their sharp reflectance curves in intensity interrogation mode.

• 한국측량학회지
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• 제34권6호
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• pp.619-627
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• 2016

Cells of a PV (photovoltaic) module can suffer defects due to various causes resulting in a loss of power output. As a malfunctioning cell has a higher temperature than adjacent normal cells, it can be easily detected with a thermal infrared sensor. A conventional method of PV cell inspection is to use a hand-held infrared sensor for visual inspection. The main disadvantages of this method, when applied to a large-scale PV power plant, are that it is time-consuming and costly. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule was applied to automatically detect defective panels using the mean intensity and standard deviation range of each panel by array. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97% or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule. In this study, we used a panel area extraction method that we previously developed; fault detection accuracy would be improved if panel area extraction from images was more precise. Furthermore, the proposed algorithm contributes to the development of a maintenance and repair system for large-scale PV power plants, in combination with a geo-referencing algorithm for accurate determination of panel locations using sensor-based orientation parameters and photogrammetry from ground control points.

• 한국멀티미디어학회논문지
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• 제15권11호
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• pp.1330-1340
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• 2012

본 논문에서는 심음신호를 이용해 강한 심 잡음이 나타나는 심장판막협착 영역을 검출하는 새로운 알고리듬을 제안하였다. 심음의 주성분을 찾거나 심 잡음을 제거하기 위한 지금까지의 많은 연구들은 대동맥판막협착증이나 승모판막협착증과 같이 강한 심 잡음이 나타나는 비정상 심음의 경우, 강한 심 잡음으로 인해 좋은 결과를 보이지 못하였다. 본 논문에서는 구간 잡음강도함수를 이용한 잡음 검출 알고리듬을 제안하였다. 제안한 구간 잡음 강도 함수는 심음 신호에서 제 1심음과 제 2심음을 검출하여, 이를 이용한 심음 구간을 설정한 후 구간 자기상관변화량을 이용하여 도출할 수 있다. 제안한 구간 잡음강도함수를 이용하여 심 잡음의 강도를 판단하고 심 잡음 유무를 검출하였다. 제안한 알고리듬으로 실험한 결과, 심장판막협착 영역 검출에서 기존의 연구보다 뛰어난 성능을 가지는 것을 확인하였다.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1288-1296
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• 2016

The reliable detection of the limited defect in TFT-LCD images is difficult due to the small intensity difference with the background. However, the proposed detection method reliably detects the limited defect by enhancing the TFT-LCD image based on the cumulative histogram and then detecting the defect through the mean and standard deviation of the enhanced image. Notably, an image enhancement using a cumulative histogram increases the intensity contrast between the background and the limited defect, which then allows defects to be detected by using the mean and standard deviation of the enhanced image. Furthermore, through the comparison with the histogram equalization, we confirm that the proposed algorithm suppresses the emphasis of the noise. Experimental comparative results using real TFT-LCD images and pseudo images show that the proposed method detects the limited defect more reliably than conventional methods.

• 대한원격탐사학회지
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• 제16권4호
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• pp.355-365
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• 2000

The interferometric correlation, or coherence, is calculated to measure the variance of the interferometric phase and amplitude within the neighbourhood of any location within the image at a result of SAR (Synthetic Aperture Radar) interferometric process which utilizes the phase information of the images. The coherence contains additional information that is useful for detecting point targets which change their location in an area of interest (AOI). In this research, a RGB colour composite image was generated with a intensity image (master image), a intensity change image as a difference between master image and slave image, and a coherence image generated as a part of SAR interferometric processing. We developed a technique performing detection of a point target movement using SAR interferometry and applied it to suitable tandem pair images of ERS-1 and ERS-2 as test data. The possibility of change detection of a point target in the AOI could be identified with the technique proposed in this research.