• 한국멀티미디어학회논문지
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• 제11권12호
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• pp.1658-1667
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• 2008

Reconstruction of 3D objects from a single view image is generally an ill-posed problem because of the projection distortion. A monocular vision based 3D object localization method is proposed in this paper, which approximates an object on the ground to a simple bounding solid and works automatically without any prior information about the object. A spherical or cylindrical object determined based on a circularity measure is approximated to a bounding cylinder, while the other general free-shaped objects to a bounding box or a bounding cylinder appropriately. For a general object, its silhouette on the ground is first computed by back-projecting its projected image in image plane onto the ground plane and then a base rectangle on the ground is determined by using the intuition that touched parts of the object on the ground should appear at lower part of the silhouette. The base rectangle is adjusted and extended until a derived bounding box from it can enclose the general object sufficiently. Height of the bounding box is also determined enough to enclose the general object. When the general object looks like a round-shaped object, a bounding cylinder that encloses the bounding box minimally is selected instead of the bounding box. A bounding solid can be utilized to localize a 3D object on the ground and to roughly estimate its volume. Usefulness of our approach is presented with experimental results on real image objects and limitations of our approach are discussed.

• 한국농촌건축학회논문집
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• 제15권2호
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• pp.9-16
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• 2013

This paper is to discover how the photogrammetry method can be utilized for recording modern architectural properties. As a result of conducting photogrammetry aimed at the main building and water supply tower of Goesan Middle School, it was possible to measure actually either complicated patterns or a damaged area on the facade. However, there appeared errors in the actual measurement of the hollow or protruded area on the facade to measure actually or of an object in the cylinder form. First, for the actual measurement of the protruded area, it is possible to complete a facade by measuring actually the protruded area separately after dividing it and complementing it on the facade, Second, concerning an object in the cylinder form, it is possible to complete one facade by matching a facade which is measured actually with a Diaver method among the MSR photogrammetry methods, and three dimensional standard coordinates which are obtained through Totalstation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.118-122
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• 1997

This paper presents a 3d image processing which uses neural networks to combine a 2D vision camera and a laser slit beam. A laser slit beam from laser source is slitted by a set of cylindrical lenses and the line image of the slit beam on the object is used to estimate the object parameters. The neural networks allow to get the 3D image parameters such as the size, the position and the orientation form the line image without knowing the camera intrinsic parameters.

• 전기의세계
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• 제19권6호
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• pp.18-25
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• 1970

The object of this project is to manifest the mechanism of deterioration phenomena for dielectrics causing corona discharge and applies it for determine the standard corona detection technique. As the results, we observed that corona discharges may occur more strongly around cylindrical shape electrode in air than hemisphere shape electrode in vacuum, so that it depends on effects such as shape of the electrode, moisture, surface coditions, etc. According to observed the deterioration of dielectrics takes place in following stages. At first the attacked surface by an electron avalanche is uniformly eroded; then pits are formed; after that sharp channels are formed which lead to break-down as a treeing. The test are accelerated with higher frequencies by the cylindrical bar shape electrode in the pulse stright detection method more sensitive than Lissajous patterns. Lissajous patterns detection method is simple but usually insensitive and has disadvantage that the magnitude of the individual discharge is not measured.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.2075-2092
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• 2017

Person re-identification is to match pedestrians observed from non-overlapping camera views. It has important applications in video surveillance such as person retrieval, person tracking, and activity analysis. However, it is a very challenging problem due to illumination, pose and viewpoint variations between non-overlapping camera views. In this work, we propose a viewpoint invariant method for matching pedestrian images using orientation of pedestrian. First, the proposed method divides a pedestrian image into patches and assigns angle to a patch using the orientation of the pedestrian under the assumption that a person body has the cylindrical shape. The difference between angles are then used to compute the similarity between patches. We applied the proposed method to real-time global multi-object tracking across multiple disjoint cameras with non-overlapping field of views. Re-identification algorithm makes global trajectories by connecting local trajectories obtained by different local trackers. The effectiveness of the viewpoint invariant method for person re-identification was validated on the VIPeR dataset. In addition, we demonstrated the effectiveness of the proposed approach for the inter-camera multiple object tracking on the MCT dataset with ground truth data for local tracking.

• 한국광학회지
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• 제32권2호
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• pp.79-85
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• 2021

본 논문에서는 빔 확산각 최소화를 통해 장거리에서 측정이 가능하도록 한 ToF 레이저 거리센서 광학계 설계에 대한 연구를 진행하였다. 거리센서는 장거리 측정 시 거리가 멀어질수록 레이저 빔의 확산각으로 인해 물체 표면에 도달하는 빔의 광량이 급격히 저하되며, 이로 인해 센서에 수신되는 광량도 감소되어 측정이 되지 않거나 측정 오차가 발생하게 된다. 일반적으로 빔 확산각을 최소화하는 광학계로 실린더 렌즈가 사용된다. 그러나 실린더 렌즈를 이용한 광학계는 광학계 크기가 커지는 문제뿐만 아니라 조립 공차의 어려움으로 인해 성능이 저하된다는 문제점이 있어 최근 비구면 렌즈를 사용하는 추세가 증가하고 있다. 따라서 본 연구에서는 실린더 렌즈를 이용한 광학계와 비구면 렌즈를 이용한 광학계의 광효율과 조립공차를 비교 분석하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.515-518
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• 1994

Holographic interferometry is a useful whole-field nondestructive testing for measuring deformations and vibrations of engineering structure. A diverging beam is used as a light source int the most of holographic interferometer practically. For a relatively small object the optical arrangement using a collimated light source has no difficulty in use technically, but for a large object it is difficult to use a collimated beam. In this study we calculate the error of measured displacement from the sensitivity vector dominated by the geometry of optical arrangement for holographic interferometer and show the result obtained with 2-D plots. A Plane surface and a cylindrical surface were chosen as objects to be calculated and computer analysis was carried out for the cases of a diverging beam and a collimated one.

• 한국전자파학회논문지
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• 제11권6호
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• pp.939-945
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• 2000

손실 반공간 묻혀 원동형 산란체와 주면 매질의 특성을 반복 기법 최적화 역산란을 적용하여 구했다. 산란파는 경계요소법을 이용하여 계산하였으며 산란체의 크기, 위치 내부매질의 비유전율, 도전율, 주변 매질의 비유전율, 도전율 등의 파라미터는 측정 산란파로부터 유전 알고리즘과 Levenberg-Marquardt 알고리즘의 혼합 알고리즘을 이요하여 역으로 계산하였다. 산란타의 측정오차에 의한 illposedness는 파수 영역에서 자수함수적으로 감쇠하는 감쇠모드를 제거하여 안정하시켰다.

• 대한토목학회논문집
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• 제10권4호
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• pp.103-112
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• 1990

본 연구는 실제크기의 첨성대 모형을 피사체로 선정하여 측정용 카메라에 의해 원형 strip과 Block을 형성한 후, bundle조성으로 촬영거리와 기준점 배치에 따른 정확도를 다양하게 분석하고 strip조합해석의 특성을 규명하므로써 전면(全面)해석을 요하는 각종 문화재 특히 원통형 구조물에 대한 최적 해석기법을 제시한 것이다. 연구결과 어느 일면에 배치된 기준점 만으로도 전면해석이 가능하며, 기준점수에 비해 그 배치가 정도에 보다 큰 영향을 미침을 알 수 있었다. 또한 구조물의 전면해석시 기준점은 X, Y, Z축 평면상에 고루 배치하는 것이 이상적이며, 근접촬영하여 strip조합수에 증가시킴에 따라 정확도가 현저히 향상되었다.

• 대한기계학회논문집A
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• 제24권11호
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• pp.2875-2882
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• 2000

Typically, the ultrasonic sensors can be used in navigation systems for modeling of the enviornment, obstacle avoidance, and map building. In this paper, we tried to approach an object classification method using the range data of the ultrasonic sensors. A characterization of the sonar scan is described that allows the differentiation of planes, corners, edges, cylindrical and rectangular pillars by processing the scanned data from three sonars. To use the data from the ultrasonic sensors as input to the neural networks, we have introduced a clustering, threshold, and bit operation algorithm for the obtained raw data, After repeated training of the neural network, the performance of the proposed method was obtained through experiments. Also, the recognition ranges of the proposed method were investigated. As a result of experiments, we found that the proposed method successfully recognized the objects within the accuracy of 78%.