• ETRI Journal
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• 제28권2호
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• pp.162-174
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• 2006

Several photogrammetric and geographic information system applications such as surface matching, object recognition, city modeling, environmental monitoring, and change detection deal with multiple versions of the same surface that have been derived from different sources and/or at different times. Surface registration is a necessary procedure prior to the manipulation of these 3D datasets. This need is also applicable in the field of medical imaging, where imaging modalities such as magnetic resonance imaging (MRI) can provide temporal 3D imagery for monitoring disease progression. This paper will present a general automated surface registration procedure that can establish correspondences between conjugate surface elements. Experimental results using light detection and ranging (LIDAR) and MRI data will verify the feasibility, robustness, and accuracy of this approach.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.248-250
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• 2003

An automatic approach and strategy for extracting building information from aerial images using combined image analysis and interpretation techniques is described in this paper. A dense DSM is obtained by stereo image matching. Multi-band classification, DSM, texture segmentation and Normalised Difference Vegetation Index (NDVI) are used to reveal building interest areas. Then, based on the derived approximate building areas, a shape modelling algorithm based on the level set formulation of curve and surface motion has been used to precisely delineate the building boundaries. Data fusion, based on the Dempster-Shafer technique, is used to interpret simultaneously knowledge from several data sources of the same region, to find the intersection of propositions on extracted information derived from several datasets, together with their associated probabilities. A number of test areas, which include buildings with different sizes, shape and roof colour have been investigated. The tests are encouraging and demonstrate that the system is effective for building extraction, and the determination of more accurate elevations of the terrain surface.

• 한국측량학회지
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• 제18권3호
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• pp.315-322
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• 2000

수치표면모형은 어떤 지역 표면의 고도를 표현하는 수치모형이다 이것은 항공사진으로부터 정사영상생성을 생성하는데 필수적인 것이며, 최근에는 항공사진에서 건물과 같은 인공구조물의 추출에도 자주 응용되고 있다 영상정합기술을 사용하면 수치표면모형을 자동적으로 생성할 수 있다. 이 연구에서는 건물지역에 대하여 수치표면모형을 자동적으로 생성하는데 적용할 수 있는 영상정합 방법을 제안하였다. 제안된 정합방법은 중복촬영된 항공사진상에서 공액점과 공액선을 찾아낸다. 공액점을 탐지하는데 있어서는 화소 값간의 상관계수뿐만 아니라 공액점쌍일가능성이 있는 것들간의 위치관계도 비교된다. 공액선 탐지에 있어서는 선 측면의 컬러 속성값, 선의 모양, 인접하는 점 및 선들간의 위치관계, 그리고 선들간의 연결관계가 비교된다. 제안된 정합방법은 건물지역을 포함하는 대상지역의 수치표면모형 자동생성에 유용할 것으로 생각된다.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.361-367
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• 2006

This paper describes a novel stereo vision based localization of free parking site, which recognizes the target position of automatic parking system. Pixel structure classification and feature based stereo matching extract the 3D information of parking site in real time. The pixel structure represents intensity configuration around a pixel and the feature based stereo matching uses step-by-step investigation strategy to reduce computational load. This paper considers only parking site divided by marking, which is generally drawn according to relevant standards. Parking site marking is separated by plane surface constraint and is transformed into bird's eye view, on which template matching is performed to determine the location of parking site. Obstacle depth map, which is generated from the disparity of adjacent vehicles, can be used as the guideline of template matching by limiting search range and orientation. Proposed method using both the obstacle depth map and the bird's eye view of parking site marking increases operation speed and robustness to visual noise by effectively limiting search range.

• ETRI Journal
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• 제34권1호
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• pp.87-97
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• 2012

This study presents an automatic matching method for generating a dense, accurate, and discontinuity-preserved digital surface model (DSM) using multiple images acquired by an aerial digital frame camera. The proposed method consists of two main procedures: area-based multi-image matching (AMIM) and stereo-pair epipolar line matching (SELM). AMIM evaluates the sum of the normalized cross correlation of corresponding image points from multiple images to determine the optimal height of an object point. A novel method is introduced for determining the search height range and incremental height, which are necessary for the vertical line locus used in the AMIM. This procedure also includes the means to select the best reference and target images for each strip so that multi-image matching can resolve the common problem over occlusion areas. The SELM extracts densely positioned distinct points along epipolar lines from the multiple images and generates a discontinuity-preserved DSM using geometric and radiometric constraints. The matched points derived by the AMIM are used as anchor points between overlapped images to find conjugate distinct points using epipolar geometry. The performance of the proposed method was evaluated for several different test areas, including urban areas.

• 산업기술연구
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• 제15권
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• pp.23-32
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• 1995

The methodology of automatic generation of tool path for rough cutting of a sculptured surface is proposed with the improved contouring method, unequal level line machining. Considering the surface shape and the diameter of the endmill, the distance between level lines is obtained. To improve MMR, initial rough cutting is processed with the large diameter endmill and the remained material is removed by the relatively small diameter endmill. Tool path is generated from the offset curve of respective level line and the interferences between the tool and workpiece are automatically avoided. After generating NC part program, the sculptured surface is machined at the vertical machining center. From the experimental results, total cutting length and machining time are reduced more effectively than conventional contouring methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.580-582
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• 2004

As the demand of large and high-resolution display panels is increased, the black light units (BLU) of the display devices play an important roles. In this study we'll deal with various defects of BLUs. Patterns of defects can be classified by the scratches, the non-uniform misprinting for the diffused reflection, the surface stains, spots and etc. Due to these distorted patterns the high-resolution and high-precision could be impeded. We'll propose the visual inspection system to detect various defects by pattern-matching.

• 한국측량학회지
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• 제38권5호
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• pp.477-486
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• 2020

Drone has been widely used for many applications ranging from amateur and leisure to professionals to get fast and accurate 3-D information of the surface of the interest. Most of commercial softwares developed for this purpose are performing automatic matching based on SIFT (Scale Invariant Feature Transform) or SURF (Speeded-Up Robust Features) using nadir-looking stereo image sets. Since, there are some situations where not only nadir and nadir-looking matching, but also nadir and oblique-looking matching is needed, the existing software for the latter case could not get good results. In this study, a matching experiment was performed to utilize images with differences in geometry. Nadir and oblique-looking images were acquired through drone for a total of 2 times. SIFT, SURF, which are feature point-based, and IMAS (Image Matching by Affine Simulation) matching techniques based on affine transformation were applied. The experiment was classified according to the identity of the geometry, and the presence or absence of a building was considered. Images with the same geometry could be matched through three matching techniques. However, for image sets with different geometry, only the IMAS method was successful with and without building areas. It was found that when performing matching for use of images with different geometry, the affine transformation-based matching technique should be applied.

• 한국측량학회지
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• 제27권1호
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• pp.751-760
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• 2009

본 연구는 영상정합의 주요 과정에 라이다데이터를 적용함으로서 정합과정의 효율성 및 결과의 신뢰도를 향상시키기 위한 전략 및 방법을 개발하는 것을 목표로 하였다. 영상정합은 정합대상객체를 선택하고, 이와 일치된 정합객체를 검색하며, 정합결과의 품질을 평가하는 과정으로 이루어진다. 본 연구는 이러한 영상정합의 각 과정에 라이다데이터를 적용하는 방법을 제시하였다. 제안된 방법을 중해상도 항공 디지털 영상과 이와 동시에 관측된 라이다데이터를 적용하여 실험하였다. 적용된 결과를 라이다데이터 대신에 가상의 수평면을 이용하는 기존의 방법과 대비하여 분석하였다. 그 결과, 제안된 방법이 기존의 방법보다 향상된 성능을 보이는 것을 확인할 수 있었다. 본 연구의 결과는 현존하는 상업용 디지털영상정합자동화 프로그램의 정합성능을 개선하고, 영상정합의 결과를 라이다데이터와 결합하여 생성된 DEM의 품질을 제고하는 것에 기여한다.

• 전자공학회논문지S
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• 제36S권7호
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• pp.104-115
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• 1999

본 논문은 세 개의 카메라로부터 얻어진 영상에서 표면 깊이 정보를 재구성하여 얼굴의 3차원 모델을 생성하는 효율적인 방법을 제안한다. 논문에서는 Trinocular 영상을 사용하여 binocular 영상 사용 시 발생하는 폐색 영역 문제와 깊이 해상도 한계를 개선하였다. 또한, MPC_MBS (Matching Pixel Count Multiple Baseline Stereo) 유사도 측정 방법을 제안하여 영상 정합 시 발생하는 Boundary overreach 현상을 줄이고 정합의 정확도와 정밀도를 개선하였다. 이 방법은 정합 때 발생하는 중복 계산을 제거함으로써 계산 시간도 줄일 수 있다. 모델 생성 시에는 추출된 변위 정보를 2차원 보간에 의해 소수점 단위까지 확장하여 연속적인 표면 깊이 정보를 추출하였고, 이로부터 일정 간격의 초기 삼각형 매쉬 모델을 생성하였다. 또한 삼각형 매쉬 모델의 데이터 크기를 줄이기 위하여 사용자가 지정하는 오차 이내에서 같은 평면으로 근사화 되는 꼭지점을 병합하는 알고리듬을 제안하여 효율적인 얼굴 모델 생성이 이루어지도록 하였다.