• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.213-219
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• 2013

Recently, with the rapid advancement in information and communication technology, indoor location-based services(LBSs) that require precise position tracking have been actively studied with outdoor-LBS using GPS. However, in case of a ship which consists of steel structure, it is difficult to measure a precise localization due to significant ranging error by the diffraction and refraction of radio waves. In order to reduce location measurement errors that occur in these indoor environments, this paper presents distance compensation algorithms that are suitable for a narrow passage such as ship corridors without any additional sensors by using UWB(Ultra-wide-band), which is robust to multi-path and has an error in the range of a few centimeters in free space. These improvement methods are that Pythagorean theory and adjacent node technique are used to solve the distance error due to the node deployment and distance variation analysis technique is applied to reduce the ranging errors which are significantly fluctuated in the corner section. The experimental results show that the number of nodes and the distance error are reduced to 66% and 57.41%, respectively, compared with conventional CSS(Chirp spread spectrum) method.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.2 s.302
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• pp.11-18
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• 2005

To detect vehicles in image, first the image is transformed with the steerable pyramid which has independent directions and levels. Feature vectors are the collection of filter responses at different scales of a steerable image pyramid. For the detection of vehicles in image, feature vectors in feature points of the vehicle image is used. First the feature points are selected with the grid points in vehicle image that are evenly spaced, and second, the feature points are comer points which m selected by human, and last the feature points are corner Points which are selected in grid points. Next the feature vectors of the model vehicle image we compared the patch of the test images, and if the distance of the model and the patch of the test images is lower than the predefined threshold, the input patch is decided to a vehicle. In experiment, the total 11,191 vehicle images are captured at day(10,576) and night(624) in the two local roads. And the $92.0\%$ at day and $87.3\%$ at night detection rate is achieved.

• The KIPS Transactions:PartB
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• v.9B no.5
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• pp.681-688
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• 2002

This paper proposes a system detecting the area of traffic sign, which uses color rate as the information of colors, and corner point and distance rate as the information of morphology. In this system, a candidate area is extracted by performing dilation operation on the binary image made by the color rate of R, G, B components and by detecting corner point and center point through mask. The area of traffic sign with varied shapes is extracted by calculating the distance rate from center point, which is the information of morphology. The results of this experiment demonstrate that in this system which is invariable regardless of its size and location, it is possible to extract the exact area from varied traffic signs such as the shapes of triangle, circle, inverse triangle, and square as well as from the images at both day and night when brightness value is greatly different. Moreover, it demonstrates great accuracy and speed in processing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.6
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• pp.629-635
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• 2012

Tracked robots usually have poor localization performance because of slippage of their tracks. This study proposes a new localization method for tracked robots that uses fuzzy fusion of stereo-camera-based visual odometry and encoder-based wheel odometry. Visual odometry can be inaccurate when an insufficient number of visual features are available, while the encoder is prone to accumulating errors when large slips occur. To combine these two methods, the weight of each method was controlled by a fuzzy decision depending on the surrounding environment. The experimental results show that the proposed scheme improved the localization performance of a tracked robot.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.250-251
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• 2010

디지털 카메라의 보급으로 이미지처리 분야에서 정지영상을 이용한 다양한 기술 개발이 화두가 되고 있다. 스테레오 영상은 정지영상보다 소비자의 시각적 욕구를 충족시킬 수 있는 영상을 표현하기 때문에 스테레오 영상기술에 대한 관심이 높아지고 있다. 본 논문에서는 하나의 카메라로 같은 객체를 다른 위치에서 찍은 2장의 정지영상을 통해 스테레오 영상을 제작하는 방법을 제안한다. 실험 영상으로 디지털카메라로 찍은 좌측 영상과 우측영상을 사용한다. 두 영상의 제어점이 될 코너를 검출한 후, 유클리드의 좌표로 바꿔준다. 이 좌표들을 통해 각 제어점에 인접해 있는 좌표 4개를 추출한다. 이 인접 좌표들이 우측 정지 영상의 인접 좌표에 매칭 되는 횟수를 계산하여, 가장 많은 매칭 좌표를 갖는 스케일 요소로 좌측 정지영상을 회전과 이동시켜 목적 영상인 우측 영상에 매칭시킴으로써 스테레오 영상을 구현한다.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.419-428
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• 2011

This paper suggests a judgement method for an inclined plane before entrance of it and the detection of obstacle position. Main idea is started from the assumption that obstacle is always on the bottom plane, and corner appears at this position. The process to detect the obstacle consists of three steps. First the 3D data using stereo matching is acquired to detect an obstacle. Second a bottom plane is extracted by using limit condition. Last the obstacle position is found by using Harris corner detection. Obstacle position detection on an inclined plane was verified by outdoor and indoor experiment. In error analysis, it is confirmed that an average error of obstacle detection in outdoor was larger than the error in indoor but the error are within about 0.030 m. This method will be applied to unmanned vehicles to navigate under various environment.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.66-71
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• 2009

최근 가상도시, 위치기반시스템 등 여러 분야에서 도심지역의 고해상도 DSM의 수요가 증가하고 있다. 고해상도 DSM을 획득하는데 항공 라이다 측량은 가장 효율적이고 경제적인 방법으로 인정받고 있다. 그러나 레이저 펄스는 도시건물의 모서리와 코너보다는 주로 표면에서 반사되기 때문에 일반적으로 라이다 DSM은 명확한 수직 breakline을 포함하기 힘들다. 이에 본 연구에서는 라이다 데이터와 항공영상의 결합을 통해서 고품질의 도시지역 DSM을 생성하는 새로운 방법을 제안하고자 한다. 제안된 방법은 (1) 서로 다른 두 센서에서 획득된 라이다 데이터와 영상의 기하 정합, (2) 라이다 데이터를 이용한 영상정합, (3) 영상정합을 통해 획득된 지상점과 라이다 데이터를 이용한 DSM 생성순으로 이루어진다. 영상 정합을 위한 지상점의 초기값으로 대상지의 평균고도를 높이로 사용하는 것이 아니라 라이다 데이터로부터 얻어진 높이를 사용한다면 영상 정합이 아주 정밀하게 이루어 질 수 있다. 이와 함께 정합된 영상으로부터 얻어진 지상점은 라이다 데이터 보다 더 높은 밀도를 갖게 된다. 따라서 DSM 생성을 위한 격자에 라이다 데이터와 영상정합의 결과로 얻어진 지상점 모두를 내삽에 이용하여 DSM을 생성하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.271-273
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• 2023

불수의적인 혀 움직임과 떨림은 다른 신체 부위의 떨림증상이 없이 혀만 움직이는 증상을 말하며, 신경 정신과적 문제와 한의학의 기혈허약 등의 증상에 의해 발생할 수 있다. 혀 영상 촬영 장치로 정면과 측면의 혀를 연속을 촬영하여 혀의 움직임과 떨림을 탐색하려 한다. 혀의 표면은 코너와 같은 특징점을 구하기 어려운 모양이므로 혀의 움직임의 특성을 찾아내는 것은 매우 어려운 일이다. 움직임을 추적하는 방법 중에서 Farnebäck optical flow 방법은 모든 픽셀에 대해서 optical flow를 계산하여 혀의 움직임을 추적할 수 있었다. 이러한 움직임의 크기를 정면과 측면 영상에 대해서 구할 수 있었고, 움직임의 방향도 구할 수 있었다. 혀의 움직임과 떨림에 대한 위치별 정보와 세기 정보를 이용하여 건강상태를 진단할 수 있을 것으로 생각된다.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.634-643
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• 2023

Purpose: Underground common duct fires are steadily occurring, and the proportion of property damage is particularly large among property and human casualties caused by fires. Especially, cable fires that occur in common areas can spread vertically quickly and pose a great risk. This paper aims to scientifically analyze the nature of the fire by reproducing the fire through experiments. Method: To analyze the characteristics of cable fires in underground common duct, heat release rate and temperature changes were measured through Room-corner (ISO 9705) test, and the vertical and horizontal propagation of cable fires was quantitatively compared and analyzed. Result: The Room Corner Test (ISO 9705) was used to compare the temperature changes at each data logger point. The results showed that the time it took for the fire to reach the ignition temperature in the horizontal and vertical directions from the center point of the first-tier cable was 589 seconds and 536 seconds, respectively, which means that the vertical fire propagation is 53 seconds faster than the horizontal propagation. This proves that the vertical propagation of fire is relatively faster than the horizontal propagation. The horizontal propagation speed of the fire was also compared for each floor cable tray. The results showed that the third-tier cable propagated at 3.4 times the speed of the second-tier cable, and the second-tier cable propagated at 1.5 times the speed of the first-tier cable. This means that the higher the cable is located, the faster the fire spreads and the larger the fire becomes. Conclusion: This study identified the risks of cable fires and analyzed the risks of vertical fire propagation during cable fires based on the results of the Room Corner Test. Studies to prevent the spread of fire and fire response policies to prevent vertical fire propagation are required. The results of this study are expected to be used to assess the fire risk of common areas and other fires.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.430-439
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• 2006

This paper presents the a measured path-loss characteristics for mobile communications beyond 3G in microcellular residential area and street microcell at 3.4, 5.3, and 6.4 GHz band signals. The residential area is divided into two sections, one of which is composed of fifteen-story appartment buildings. The other section comprises four-story houses. The street microcell is classified line-of-sight(LOS) and nonline-of-sight(NLOS) areas. Both residential areas have standard deviations independent of the residential area classification, whereas the path loss exponents in the apartments is higher than those in area for same frequencies. A two-ray model is applied to analyse the path-loss charateristics in LOS areas. In LOS areas, an empirical breakpoint, whose distance is 6 percent shorter than a theorical breakpoint, is founded. Further, a sudden power level drop occurs at a transition point from LOS region to NLOS area. Path loss exponent is found to be significantly higher for non-LOS region than for LOS region. The power level drop due to corner loss and path-loss exponents both increase as the distance between the transmitter and the corner increases.