• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.810-813
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• 2004

Indexing and Retrieving images from large and varied collections using image content as a key is a challenging and important problem in computer vision application. In this paper, a color Content-based Image Retrieval (CBIR) system using hierarchical Region of Interest (ROI) query and indexing is presented. During indexing process, First, The ROIs on every image in the image database are extracted using a region-based image segmentation technique, The JSEG approach is selected to handle this problem in order to create color-texture regions. Then, Color features in form of histogram and correlogram are then extracted from each segmented regions. Finally, The features are stored in the database as the key to retrieve the relevant images. As in the retrieval system, users are allowed to select ROI directly over the sample or user's submission image and the query process then focuses on the content of the selected ROI in order to find those images containing similar regions from the database. The hierarchical region-of-interest query is performed to retrieve the similar images. Two-level search is exploited in this paper. In the first level, the most important regions, usually the large regions at the center of user's query, are used to retrieve images having similar regions using static search. This ensures that we can retrieve all the images having the most important regions. In the second level, all the remaining regions in user's query are used to search from all the retrieved images obtained from the first level. The experimental results using the indexing technique show good retrieval performance over a variety of image collections, also great reduction in the amount of searching time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권9호
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• pp.3782-3796
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• 2020

A three-dimensional (3D) reconstruction is an important research area in computer vision. The ability to detect and match features across multiple views of a scene is a critical initial step. The tracking matrix W obtained from a 3D reconstruction can be applied to structure from motion (SFM) algorithms for 3D modeling. We often fail to generate an acceptable number of features when processing face or medical images because such images typically contain large homogeneous regions with minimal variation in intensity. In this study, we seek to locate sufficient matching points not only in general images but also in face and medical images, where it is difficult to determine the feature points. The algorithm is implemented on an adaptive threshold value, a scale invariant feature transform (SIFT), affine SIFT, speeded up robust features (SURF), and affine SURF. By applying the algorithm to face and general images and studying the geometric errors, we can achieve quasi-dense matching points that satisfy well-functioning geometric constraints. We also demonstrate a 3D reconstruction with a respectable performance by applying a column space fitting algorithm, which is an SFM algorithm.

• 전자공학회논문지
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• 제51권1호
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• pp.116-125
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• 2014

운전자 보조 시스템에서 도로 상태 정보는 안전한 운전을 위한 중요한 정보를 제공한다. 자동차에서의 입력 영상은 일반적으로 불필요한 영역도 포함하므로 도로 상태를 파악을 위한 관심영역(ROI)을 결정하고 나머지 영역을 제거한 뒤 관심영역만 남겨 두면 연산 시간을 줄일 수 있다. 본 논문에서는 도로를 나타내는 특징적인 선분과 이로부터 얻어지는 소멸점을 이용하여 도로 영역을 찾는 영상기반의 도로 관심영역 결정 알고리즘을 제안한다. 선분들은 Canny 가장자리 탐지법과 허프 변환을 이용하여 찾고 소멸점은 칼만 필터를 이용하여 추적함으로써 잡음의 영향에 의한 오동작을 방지한다. 초기화 과정을 거치면 도로 관심영역을 매 프레임마다 정확히 결정할 수 있다. 제안한 방식은 C++와 OpenCV 라이브러리를 이용하여 SW로 구현하였으며 다양한 블랙박스 영상으로부터 도로 관심영역을 얻는데 성공하였다. 실험 결과 제안한 알고리즘은 잡음에 강하다는 것을 확인하였다.

• Smart Structures and Systems
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• 제25권2호
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• pp.135-153
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• 2020

There has been a sustained interest towards the non-contact structural displacement measurement by means of videogrammetric technique. On the way forward, one of the major concerns is the spurious image drift induced by temperature variation. This study therefore carries out an investigation into the temperature effect of videogrammetric technique, focusing on the exploration of the mechanism behind the temperature effect and the elimination of the temperature-caused measurement error. 2D videogrammetric measurement tests under monotonic or cyclic temperature variation are first performed. Features of measurement error and the casual relationship between temperature variation and measurement error are then studied. The variation of the temperature of digital camera is identified as the main cause of measurement error. An excellent linear relationship between them is revealed. After that, camera parameters are extracted from the mapping between world coordinates and pixels coordinates of the calibration targets. The coordinates of principle point and focal lengths show variations well correlated with temperature variation. The measurement error is thought to be an outcome mainly attributed to the variation of the coordinates of principle point. An approach for eliminating temperature-caused measurement error is finally proposed. Correlation models between camera parameters and temperature are formulated. Thereby, camera parameters under different temperature conditions can be predicted and the camera projective matrix can be updated accordingly. By reconstructing the world coordinates with the updated camera projective matrix, the temperature-caused measurement error is eliminated. A satisfactory performance has been achieved by the proposed approach in eliminating the temperature-caused measurement error.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.3188-3207
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• 2017

In this paper, we propose an image enhancement algorithm to improve license plate extraction rate in various environments (Day Street, Night Street, Underground parking lot, etc.). The proposed algorithm is composed of image enhancement algorithm and license plate extraction algorithm. The image enhancement method can improve an image quality of the degraded image, which utilizes a histogram information and overall gray level distribution of an image. The proposed algorithm employs an interpolated probability distribution value (PDV) in order to control a sudden change in image brightness. Probability distribution value can be calculated using cumulative distribution function (CDF) and probability density function (PDF) of the captured image, whose values are achieved by brightness distribution of the captured image. Also, by adjusting the image enhancement factor of each part region based on image pixel information, it provides a function that can adjust the gradation of the image in more details. This processed gray image is converted into a binary image, which fuses narrow breaks and long thin gulfs, eliminates small holes, and fills gaps in the contour by using morphology operations. Then license plate region is detected based on aspect ratio and license plate size of the bound box drawn on connected license plate areas. The images have been captured by using a video camera or a personal image recorder installed in front of the cars. The captured images have included several license plates on multilane roads. Simulation has been executed using OpenCV and MATLAB. The results show that the extraction success rate is more improved than the conventional algorithms.

• Smart Structures and Systems
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• 제15권2호
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• pp.335-353
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• 2015

Previous long-term measurements of the Uldolmok tidal current power plant showed that the structure's natural frequencies fluctuate with a constant cycle-i.e., twice a day with changes in tidal height and tidal current velocity. This study aims to improve structural health monitoring (SHM) techniques for offshore structures under a harsh tidal environment like the Uldolmok Strait. In this study, lab-scale experiments on a simplified offshore structure as a lab-scale test structure were conducted in a circulating water channel to thoroughly investigate the causes of fluctuation of the natural frequencies and to validate the displacement estimation method using multimetric data fusion. To this end, the numerical study was additionally carried out on the simplified offshore structure with damage scenarios, and the corresponding change in the natural frequency was analyzed to support the experimental results. In conclusion, (1) the damage that occurred at the foundation resulted in a more significant change in natural frequencies compared with the effect of added mass; moreover, the structural system became nonlinear when the damage was severe; (2) the proposed damage index was able to indicate an approximate level of damage and the nonlinearity of the lab-scale test structure; (3) displacement estimation using data fusion was valid compared with the reference displacement using the vision-based method.

• 한국통신학회논문지
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• 제41권11호
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• pp.1507-1514
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• 2016

Full-image guided filter는 커널 윈도우 영역만 필터링에 반영되는 기존의 커널 윈도우 기반 가이드 필터와 달리 가중치 전파 도식과 양방향 모델이 적용되어 영상의 모든 픽셀이 필터링에 반영된다. 이로써 가이드 필터의 경계 보존과 평활화 등의 가이드 이미지 필터의 특성을 유지하면서도 계산 복잡도를 개선할 수 있다. 본 논문에서는 full-image guided filter의 더 빠른 처리가 필요한 스테레오 비전 및 각종 실시간 시스템 분야에 적용될 수 있도록 효율적인 하드웨어 구조를 제안하였다. 필터링 프로세스에서 발생하는 각종 데이터의 종속성 분석과 영상의 PSNR 분석, 데이터 빈도 분석 등을 통하여 적합한 하드웨어 구조를 제안하였다. 또한 양방향 모델이 적용된 가중치 연산 모듈의 휴식 구간이 최소화되도록 효율적인 스케줄링을 하였고 실시간 처리가 가능하게 하였다. 제안한 하드웨어 구조는 동부하이텍 0.11um 표준셀 라이브러리로 합성하였을 경우 최대 동작주파수 214MHz(384*288 영상: 965 fps)와 76K(내부 메모리 제외) 게이트의 하드웨어 복잡도를 나타냈다.

• 디자인학연구
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• 제12권3호
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• pp.5-14
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• 1999

급속하고 광범위하게 변화하는 경쟁적 환경 속에 있는 우리는 교육의 역할이 더욱 중대함을 인식하고 있다. 우리 사회가 처한 도전은 어떻게 정보를 다루고 그것을 어떻게 지식으로 전환하느냐이다. 이미 많은 학교에서 컴퓨터를 사용하여 학습효과를 향상하려고 노력하고 있다. 인터그레이티드 미디어(Integrated Media)의 교육활용은 학습내용을 새롭고 흥미롭게 제시하는 것 이외에도 종전의 미디어 시스템들이 가지지 못했던 학생이 직접 참여하는 방법으로 배우는 과정에 있어 시각, 청각, 그리고 시뮬레이션의 경험을 사용한 대화형 교육의 높은 유용성 즉, 상호작용적 특성을 가질 뿐만 아니라 대량의 정보를 저장, 통신, 관리, 처리하는 능력이 탁월하다는 효율성과 효과성을 든다. 본 연구는 인터그레이티드 미디어(Integrated Media)의 본질을 파악하고 아동들의 심리 및 인지능력을 검토하여 아동을 위한 교육결과물을 제작하는 데 있어 실질적인 문제제기를 하였으며, 그 해결방안으로써 부분적이기는 하나 그것의 교육효과와 효율성을 높이기 위한 디자인적인 관점과 내용면의 해결책을 제시하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1591-1596
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• 1991

The present paper describes a method of recognizing a polyhedron employing the notion of network constraint analysis. Typical difficulties in three-dimensional object recognition, other than shading, reflection, and hidden line problems, include the case where appearances of an object vary according to observation points and the case where an object to be recognized is occluded by other objects placed in its front, resulting in incomplete information on the object shape. These difficulties can, however, be solved to a large extent, by taking account of certain local constraints defined on a polyhedral shape. The present paper assumes a model-based vision employing an appearance-oriented model of a polyhedron which is provided by placing it at the origin of a large sphere and observing it from various positions on the surface of the sphere. The model is actually represented by the sets of adjacent faces pairs of the polyhedron observed from those positions. Since the shape of a projected face gives constraint to that of its adjacent face, this results in a local constraint relation between these faces. Each projected face of an unknown polyhedron on an acquired image is examined its match with those faces in the model, producing network constraint relations between faces in the image and faces in the model. Taking adjacency of faces into consideration, these network constraint relations are analyzed. And if the analysis finally provides a solution telling existence of one to one match of the faces between the unknown polyhedron and the model, the unknown polyhedron is understood to be one of those memorized models placed in a certain posture. In the performed experiment, a polyhedron was observed from 320 regularly arranged points on a sphere to provide its appearance model and a polyhedron with arbitrarily postured, occluded, or imposed another difficulty was successfully recognized.

• 한국정보처리학회논문지
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• 제7권12호
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• pp.3910-3922
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• 2000

현재의 전력시스템은 컴퓨터와 통신기술의 발전으로 분산시스템인 EMS(Energy Menagement System)/SCADA(Super-vision Control and Data Acquisition) 형태로 운영되어 전력의 생산, 전송 그리고 분배가 효과적으로 이루어지고 있다. 그러나 각 시스템은 언어, 운영체제 그리고, 통신프로토콜이 서로 다른 제품으로 구성되어 시스템간에 데이터를 교환하는데 많은 어려움이 따르고 있다. 이러한 문제를 해결하기 위해서는 미국 전력연구소는 전력제어센터간의 통신을 담당하는 ICCP(Inter-Control Center Protocol)라는 새로운 형태의 통신규약을 발표하였다. ICCP는 자동화용 표준 통신규약인 MMS(Manufacturing Message Specification)를 응용계층의 하부 규약으로 지정함으로써 서로 다른 기종의 제어센터간의 원활한 통신을 지원한다. 본 논문은 ICCP의 특징과 MMS와 ICCP가 어떻게 상호 연관되는가를 밝힌다. ICCP에서 이용하는 MMS 라이브러리(library)의 86개의 서비스 중 일부 서비스를 구현한 후 이것을 이용하여 TCP/IP 환경 하에서 ICCP의 기본이면서 핵심적인 기능을 구현한다. 그 다음, ICCP 프로토콜을 이용하여 EMS간의 통신을 모델링하고, 전력센터간의 실제 데이터 교환을 윈도우 환경 하에서 구현하여 ICCP 프로토콜의 동작과 기능을 보여준다.