• Korean Journal of Remote Sensing
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• v.18 no.4
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• pp.233-242
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• 2002

In this paper, an epipolar model without the ephemeris data is proposed. Also, various epipolar models such as the epipolar geometry of perspective sensor, the one proposed by Gupta and Hartley and the one based on the Orun and Natarajan's sensor model are reviewed and their accuracy are quantitatively analyzed using devised measure. Modeling data from ground control points, ground control points, ephemeris data and independent checking points are selected on SPOT over Taejon and Boryung area and KOMPSAT over Taejon and Nonsan area. Based on the results, the epipolar model of perspective sensor and the one by Gupta and Hartley have the average accuracy within 1 pixel but show high errors in several checking points. The proposed epipolarity model provides better results than that of perspective sensor and by Gupta and Hartley. Also, it shows the accuracy similar to the one based on Orun and Natarajan's sensor model.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.21-24
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• 1998

논문은 상대적인 3차원 정보를 추출하기 위하여 스테레오 정합 알고리듬에 에피폴라 기하학을 적용하였다. 카메라로부터 입력받은 영상에서 추출된 특징 점으로부터 에피폴라 기하학 구조를 구성한다. 이렇게 구한 에피폴라 기하학 정보는 스테레오 영상에서의 정합 점들 간의 기하학적인 상관관계를 구성하고 조밀한 변이영상을 추출한다 실험결과를 통하여 제안된 알고리듬이 실제 공간상에서 대상물체를 실감 있게 표현함을 알 수 있다.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.81-88
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• 2007

The geometry of satellite image captured by linear CCD sensor is different from that of frame camera image. The fact that the exterior orientation parameters for satellite image with linear CCD sensor varies from scan line by scan line, causes the difference of image geometry between frame and linear CCD sensor. Therefore, we need the epipolar geometry for linear CCD image which differs from that of frame camera image. In this paper, we proposed a method of resampling linear CCD satellite image in epipolar geometry under the assumption that image is not formed in perspective projection but in parallel projection, and the sensor model is a 2D affine sensor model based on parallel projection. For the experiment, IKONOS stereo images, which are high resolution linear CCD images, were used and tested. As results, the spatial accuracy of 2D affine sensor model is investigated and the accuracy of epipolar resampled image with RFM was presented.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.6
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• pp.633-641
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• 2008

This study introduces the method of detecting and restoring occlusion areas by using epipolar algorithm and K-means classification algorithm for true ortho-photo generation. In the past, the techniques of detecting occlusion areas are using the reference images or information of buildings. But, in this study the occlusion areas can be automatically detected by using DTM data and exterior orientation parameters. The detected occlusion areas can be restored by using anther images or the computed values which are determined in K-means classification algorithm. In addition, this method takes advantages of applying epipolar algorithm in order to find same location in overlapping areas among images.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.91-94
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• 2012

본 논문에서는 3D 콘텐츠 제작에 있어 입체피로를 최소화하기 위한 영상의 수직시차 제거과정에 있어 사진측량기반의 강인기법을 제안하고자 한다. 영상의 수직시차 제거 과정은 크게 기하추정 단계와 에피폴라 변환 단계로 구성된다. 본 논문에서는 기하추정을 위해 사진측량에서 널리 활용되고 있는 공면조건 기반 상대표정 알고리즘을 적용한다. 이 때 상대표정 알고리즘에는 자동 정합점 추출에 따른 오정합과 위치오차에 강인성을 확보하기 위해 제약조건을 도입한 베이지안 접근방식을 적용하고자 하며, 이를 바탕으로 수행되는 에피폴라 변환에는 영상의 왜곡과 원 영상 대비 변형을 최소화하기 위해 공선조건기반의 중심투영변환기법을 적용하고자 한다. 알고리즘의 성능검증을 위한 비교 알고리즘으로, 기하추정에는 8점 알고리즘과 스테레오 캘리브레이션 기법이 사용되었으며 에피폴라 변환에는 Hartley 방법과 Bouguet 방법이 사용되었다. 실험결과는 제안알고리즘의 높은 정확도와 강인성, 그리고 활용적 가치를 보여주었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.322-324
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• 2020

본 논문에서는 스테레오 영상으로부터 얻은 특징점들을 활용하여 기초행렬(Fundamental matrix)을 추정하는 실험을 한다. 획득한 영상들은 보정이 되어 있으며, 특징점 추출 후 매칭은 RANSAC 등의 기존 알고리즘을 활용한다. 기초 행렬을 얻기 위해 스테레오 영상으로부터 정의되는 에피폴라 점, 에피폴라 선, 에피폴라 평면을 정의하고, 이들로부터 얻을 수 있는 기하학적 관계식을 활용하여 기초행렬을 수학적으로 추정해 보고, 실험으로 수학적 이론을 검증해 본다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.446-448
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• 1998

본 논문은 두 장의 스테레오 영상으로부터 자동적으로 특징점 정합을 수행하도록 하는 한 방법을 제안한다. Correlation기반의 특징점 정합을 빠르고 안정적으로 수행하며 이 때에 발생하는 애매성 문제에 대한 해결방법을 제시한다. 또한, LMedS방법을 사용하여 outlier를 효과적으로 제거시키고 에피폴라 기하를 이용하여 정합의 성능을 향상시킨다. 실내, 실외 영상에 대한 다양한 실험결과는 본 논문에서 제안하는 방법이 빠르고 효율적임을 보여준다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.6_1
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• pp.455-461
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• 2013

Kompsat-3 is an optical high-resolution earth observation satellite launched in May 2012. The AEISS sensor of the Korean satellite provides 0.7m panchromatic and 2.8m multi-spectral images with 16.8km swath width from the sun-synchronous near-circular orbit of 685km altitude. Kompsat-3 is more advanced than Kompsat-2 and the improvements include better agility such as in-track stereo acquisition capability. This study investigated the characteristic of the epipolar curves of in-track Kompsat-3 stereo images. To this end we used the RPCs(Rational Polynomial Coefficients) to derive the epipolar curves over the entire image area and found out that the third order polynomial equation is required to model the curves. In addition, we could observe two different groups of curve patterns due to the dual CCDs of AEISS sensor. From the experiment we concluded that the third order polynomial-based RPCs update is required to minimize the sample direction image distortion. Finally we carried out the experiment on the epipolar resampling and the result showed the third order polynomial image transformation produced less than 0.7 pixels level of y-parallax.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.1
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• pp.40-48
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• 2002

Three-Dimensional scene reconstruction from images acquired with different viewpoints is possible as estimating Fundamental matrix(F-matrix) that indicates the epipolar geometry of two images. Correspondence points required to calculate F-matrix of two images include noise such as miss matches, so generally it is hard to calculate F-matrix accurately. In this paper, we classify noise into two types; outlier and minute noise. we propose SSOR algorithm that estimate F-matrix effectively. SSOR algorithm is rejecting outlier step by step in a noise environment. To evaluate the performance of proposed algorithm we simulated with synthetic images and real images. As a result of simulation we show that proposed algorithm is better than conventional algorithms.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.1
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• pp.39-47
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• 2014

In this study, the epipolar images were created by both methods of resolution adjustment and piecewise approach using RPC(Rational Polynomial coefficients) and ancillary data of IKONOS-2 and SPOT-5 satellite images whose resolutions are different from each other. The stereo geometry of these two satellite images was analyzed and the RPC block modelling was accomplished for generating epipolar images. In order to evaluate the accuracy of created epipolar images, the y-parallaxes were analyzed for the specific points which were apparently identified in mountainous, plain and urban area. Also the RMSEs of the specific points were calculated using the coordinates from the epipolar stereo images and the coordinates from the block triangulation. Y-parallaxes were within one pixel and the RMSEs were within two meters for X, Y and Z each.