• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.201-205
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• 2007

In the post-Cold War era, acquisition technique of high-resolution satellite imagery (HRSI) has begun to commercialize. IKONOS-2 satellite imaging data is supplied for the first time in the 21st century. Many researchers testified mapping possibility of the HRSI data instead of aerial photography. It is easy to renew and automate a topographical map because HRSI not only can be more taken widely and periodically than aerial photography, but also can be directly supplied as digital image. In this study matching size of IKONOS Geo-level stereo image is presented lot production of digital elevation model (DEM). We applied area based matching method using correlation coefficient of pixel brightness value between the two images. After matching line (where "matching line" implies straight line that is approximated to complex non-linear epipolar geometry) is established by exterior orientation parameters (EOPs) to minimize search area, the matching is tarried out based on this line. The experiment on matching size is performed according to land cover property, which is divided off into four areas (water, urban land, forest land and agricultural land). In each of the test areas, window size for the highest correlation coefficient is selected as propel size for matching. As the results of experiment, the proper size was selected as $123{\times}123$ pixels window, $13{\times}13$ pixels window, $129{\times}129$ pixels window and $81{\times}81$ pixels window in the water area, urban land, forest land and agricultural land, respectively. Of course, determination of the matching size by the correlation coefficient may be not absolute appraisal method. Optimum matching size using the geometric accuracy therefore, will be presented by the further work.

• 전자공학회논문지B
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• 제30B권1호
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• pp.29-37
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• 1993

The purpose of this paper is to estimate the attitude and the position of SPOT satellite which are needed in producing DEM(Digital Elevation Model) using SPOT satellite image pairs. DEM extraction is consists of three parts. First part is the modeling of satellite position and atitude, second part is the matching of two images to find corresponding point of them and third part is to calculate the elevation of each point by using the result of the first and second part. For modeling inaccessible area, extended modeling algorithm which removes the GCP(Ground Control Point) most errorneous from the GCPs extracted from map iteratively is proposed According to the experiments using a collinearity equation, the second order polynomials are shown to the optimal for .omega.(pitch), and Zs parameters while the first order ones for .kappa.(yaw) .PHI.(roll), Xs, and Ys parameters. The input images used in this paper are 6000*6000 level 1A panchromatic digital SPOT images of Chungchong-do, Korea. With 30 GCPs, experiments on SPOT images show that the planimetric and altimetric RMS errors are 7.11m and 7.10m, respectively, for test points.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권4호
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• pp.267-273
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• 2005

Stereo image analysis has been an important tool for reconstructing 3D terrain. By In its nature, occlusion is one of difficulties Ive cannot avoid in stereo matching. This paper presents a study on occlusion detection by employing LRC(Left-Right Check) and OCC(Occlusion Constraint) and how we can improve the accuracy of DEM(Digital Elevation Model) y using interpolated data into the detected occluded area. Experimental results show that these method can effectively detect occluded regions and improve the accuarcy of DEM using the occlusion detection.

• 한국측량학회지
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• 제28권4호
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• pp.463-469
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• 2010

화성의 고도정보를 제공하는 MOLA 센서는 화성전역에 대한 데이터를 제공하지 못하므로, 수치표고모형을 만들기 위해서는 MOC-NA영상을 이용한 영상정합이 수행되어야만 한다. 그러나 특색(feature)이 적고 명암대비가 낮은 화성영상의 특성상, 자동 영상정합은 어려운 실정이다. 본 논문은 MOC-NA 영상에 대하여 영역기준 영상정합에 기반한 반 자동 영상정합의 알고리즘을 다룬다. 공액점을 나타내는 시드(seed)포인트 들이 수동으로 스테레오 영상에 추가되고 이를 바탕으로 특징점들이 자동으로 삽입된다. 각 영상의 특징점들은 서로의 초기 공액점으로 사용되며, 영역기준 영상정합으로 정제된다. 영상정합의 과정 중 정합에 실패한 점들은 초기 공액점의 위치를 정합에 성공한 주변의 여섯 점들을 이용하여 재 계산한 후 정제된다. 타깃영상과 검색영상의 역할을 바꾸어 수행한 영상정합의 질적 평가 결과, 97.3%의 점들이 한 화소 이하의 절대거리를 나타내었다.

• 대한원격탐사학회지
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• 제29권5호
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• pp.487-497
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• 2013

본 연구에서는 고해상도 스테레오 영상분석에 기반하여 DSM에 존재하는 오차들을 효율적으로 검출하는 기법을 제시한다. 스테레오 영상정합을 통한 DSM 자동생성은 여러 가지 측면에서 DSM 확보를 위한 유용한 방법이 될 수 있는데, 자동생성 과정에서 발생하는 과대오차들을 포함하고 있어 이를 개선하기 위한 효율적 검출 방법이 필요하다. 본 연구에서는 고해상도 스테레오 영상을 활용한 상관계수 분석 기법을 적용하여 DSM의 모든 격자의 신뢰도를 나타낸다. 제안 기법을 적용하면, DSM 정확도에 치명적인 영향을 주어 우선적으로 보정이 요구되는 과대오차 지역을 자동으로 검출할 수 있다. 해당 지역의 참값 DSM을 활용하여 제안기법의 신뢰성을 확인하였으며 실험결과로부터 제안기법이 효율적인 DSM 보정을 위한 유용한 DSM 오차분석 기법이 될 수 있음을 확인하였다. 제안된 기법은 다양한 DSM 및 DEM 자료의 오차분석에 활용이 가능하며 따라서, 신뢰성 있는 DSM 및 DEM 확보에 유용하게 활용될 수 있을 것으로 기대한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2000년도 춘계 학술대회 논문집 통권 3호 Proceedings of the 2000 KSRS Spring Meeting
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• pp.85-90
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• 2000

백두산 지역의 JERS-1 SLC 영상과 볼리비아 지역의 RADARSAT 영상에 대해 각각 interferometry와 radargrammetry를 이용하여 수치표고모형을 제작하였다. Interferometry 는 coregistration, interferogram 작성, phase unwrapping 과정으로 나눠지는데 temporal decorrelation으로 낮은 coherence, 부정확한 궤도정보가 DEM의 정확도를 저하시키는 주요 원인으로 작용하였다. Radargrammetry는 photogrammetry와 동일한 처리과정, 즉 GCP를 이용한 stereo model 설정, 영상 matching, 고도추출단계로 이루어지지만 광학영상 과는 다른 SAR 영상의 기하학적, 방사적 특성이 고려되어야 한다.

• 전자공학회논문지S
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• 제35S권2호
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• pp.146-156
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• 1998

Thispapr proposes hybrid navigation parameter estimation using sequential aerial images. The proposed navigation parameter estimation system is composed of two parts: relative position estimation and absolute position estimation. the relative position estimation recursively computes the current velocity and absolute position estimation. The relative position estimation recursively computes the current velocity and position of an aircraft by accumulating navigation parameters extracted from two succesive aerial images. Simple accumulation of parameter values decreases reliability of the extracted parameters as an aircraft goes on navigating. therefore absolute position estimation is required to compensate for position error generated in the relative position step. The absolute position estimation algorithm combining image matching and digital elevation model(DEM) matching is presented. Computer simulation with real aerial image sequences shows the efficiency of the proposed hybrial algorithm.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.518-523
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• 2002

Nowadays the Rational Function Model (RFM), an abstract sensor model, is substituting physical sensor models for highly complicated imaging geometry. But RFM is algorithm to be required many Ground Control Points (GCP). In case of RFM of the third order, At least forty GCP are required far RFM generation. The purpose of this study is to research more efficient algorithm on GCP and accurate algorithm similar to RFM. The Polynomial Camera Model is relatively accurate and requires a little GCP in comparisons of RFM. This paper introduces how to generate Polynomial Camera Model and fundamental algorithms for construction of 3-D topographic data using the Polynomial Camera Model information in the Kompsat stereo pair and describes how to generate the 3-D ground coordinates by manual matching. Finally we tried to extract height information for the whole image area with the stereo matching technique based on the correlation.

• JSTS:Journal of Semiconductor Technology and Science
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• 제10권4호
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• pp.276-281
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• 2010

A 2.5 V feed-forward second-order deltasigma modulator for audio application is presented. A 9-level quantizer with a tree-structured dynamic element matching (DEM) was employed to improve the linearity by shaping the distortion resulted from the capacitor mismatch of the feedback digital-toanalog converter (DAC). A chopper stabilization technique (CHS) is used to reduce the flicker noise in the first integrator. The prototype delta-sigma analogto-digital converter (ADC) implemented in a 65 nm 1P8M CMOS process occupies 0.747 $mm^2$ and achieves 109.1 dB dynamic range (DR), 85.4 dB signal-to-noise ratio (SNR) in a 24 kHz audio signal bandwidth, while consuming 14.75 mW from a 2.5 V supply.

• 전기학회논문지P
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• 제59권4호
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• pp.401-404
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• 2010

In multibit Sigma-Delta Modulator, DWA(Data Weighted Averaging) among the DEM(Dynamic Element Matching) techniques was widely used to get rid of non-linearity that caused by mismatching of unit capacitor in feedback DAC path. this paper proposed the improved DWA architecture by adjusting clock timing of the existing DWA architecture. 2n Register block used for output was replaced with 2n S-R latch block. As a result of this, MOS Tr. can be reduced and extra clock can also be removed. Moreover, two n-bit Register block used to delay n-bit data code is decreased to one n-bit Register. In order to confirm characteristics, DWA for the 3-bit output with the proposed DWA architecture was designed on 0.18um process under 1.8V supply. Compared with the existing architecture. It was able to reduce the number of 222 MOS Tr.