• Title/Summary/Keyword: corresponding points

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Extraction of Corresponding Points Using EMSAC Algorithm (EMSAC 알고리듬을 이용한 대응점 추출에 관한 연구)

  • Ye, Soo-Young;Jeon, Ah-Young;Jeon, Gye-Rok;Nam, Ki-Gon
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.4 s.316
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    • pp.44-50
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    • 2007
  • In this paper, we proposed the algorithm for the extraction of the corresponding points from images. The proposed algorithm EMSAC is based on RANSAC and EM algorithms. In the RANSAC procedure, the N corresponding points are randomly selected from the observed total corresponding points to estimate the homography matrix, H. This procedure continues on its repetition until the optimum H are estimated within number of repetition maximum. Therefore, it takes much time and does not converge sometimes. To overcome the drawbacks, the EM algorithm was used for the selection of N corresponding points. The EM algorithm extracts the corresponding points with the highest probability density to estimate the optimum H. By the experiments, it is demonstrated that the proposed method has exact and fast performance on extraction of corresponding points by combining RANSAC with EM.

Extraction of Corresponding Points of Stereo Images Based on Dynamic Programming (동적계획법 기반의 스테레오영상의 대응점 탐색)

  • Lee, Ki-Yong;Lee, Joon-Woong
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.5
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    • pp.397-404
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    • 2011
  • This paper proposes an algorithm capable of extracting corresponding points between a pair of stereo images based on dynamic programming. The purpose of extracting the corresponding points is to provide the stereo disparity data to a road-slope estimation algorithm with high accuracy and in real-time. As the road-slope estimation algorithm does not require dense disparity data, the proposed stereo matching algorithm aims at extracting corresponding points accurately and quickly. In order to realize this contradictory goal, this paper exploits dynamic programming, and minimizes matching candidates using vertical components of color edges. Furthermore, the typical occlusion problem in stereo vision is solved. The proposed algorithm is proven to be effective through experiments with various images captured on the roads.

Matching Of Feature Points using Dynamic Programming (동적 프로그래밍을 이용한 특징점 정합)

  • Kim, Dong-Keun
    • The KIPS Transactions:PartB
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    • v.10B no.1
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    • pp.73-80
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    • 2003
  • In this paper we propose an algorithm which matches the corresponding feature points between the reference image and the search image. We use Harris's corner detector to find the feature points in both image. For each feature point in the reference image, we can extract the candidate matching points as feature points in the starch image which the normalized correlation coefficient goes greater than a threshold. Finally we determine a corresponding feature points among candidate points by using dynamic programming. In experiments we show results that match feature points in synthetic image and real image.

A Study on the Estimation of Camera Calibration Parameters using Cooresponding Points Method (점 대응 기법을 이용한 카메라의 교정 파라미터 추정에 관한 연구)

  • Choi, Seong-Gu;Go, Hyun-Min;Rho, Do-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.50 no.4
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    • pp.161-167
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    • 2001
  • Camera calibration is very important problem in 3D measurement using vision system. In this paper is proposed the simple method for camera calibration. It is designed that uses the principle of vanishing points and the concept of corresponding points extracted from the parallel line pairs. Conventional methods are necessary for 4 reference points in one frame. But we proposed has need for only 2 reference points to estimate vanishing points. It has to calculate camera parameters, focal length, camera attitude and position. Our experiment shows the validity and the usability from the result that absolute error of attitude and position is in $10^{-2}$.

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A Study on the Automatic Registration of Multiple Range Images Obtained by the 3D Scanner around the Object (물체 주위를 돌아가며 3차원 스캐너로 획득된 다면 이미지의 자동접합에 관한 연구)

  • 홍훈기;조경호
    • Korean Journal of Computational Design and Engineering
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    • v.5 no.3
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    • pp.285-292
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    • 2000
  • A new method for the 3D automatic registration of the multiple range images has been developed for the 3D scanners(non-contact coordinates measurement systems). In the existing methods, the user usually has to input more than 3 pairs of corresponding points for the iterative registration process. The major difficulty of the existing systems lies in that the input corresponding points must be selected very carefully because the optimal searching process and the registration results mostly depend upon the accuracy of the selected points. In the proposed method, this kind of difficulty is greatly mitigated even though it needs only 2 pairs of the corresponding input points. Several registration examples on the 3D measured data have been presented and discussed with the introduction to the proposed algorithm.

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다목적 선형계획 문제의 특성에 관한 소고

  • Park Sun-Dal;So Yeong-Seop
    • Journal of the military operations research society of Korea
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    • v.14 no.1
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    • pp.33-41
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    • 1988
  • In Multiple Objective Linear Programming (MOLP), it is well known that efficient solution and weight are correspondent to each other. The purpose of this paper is to study relationships between efficient face and the region of weight in MOLP. It is shown that the regions of weights corresponding to two efficient extreme points are also neighbor if two efficient extreme points are neighbor each other, and that the set of the efficient solutions corresponding to the common part of weight regions is efficient face. Using the above, we present a method to find the efficient solutions corresponding to a given weight and vice versa.

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다목적 선형계획 문제의 특성에 관한 소고

  • Park Sun-Dal;So Yeong-Seop
    • Journal of the military operations research society of Korea
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    • v.13 no.2
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    • pp.33-41
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    • 1987
  • In Multiple Objective Linear Programming (MOLP), it is well known that efficient solution and weight are correspondent to each other. The purpose of this paper is to study relationships between efficient face and the region of weight in MOLP. It is shown that the regions of weights corresponding to two efficient extreme points are also neighbor if two efficient extreme points are neighbor each other, and that the set of the efficient solutions corresponding to the common part of weight regions is efficient face. Using the above, we present a method to find the efficient solutions corresponding to a given weight and vice versa.

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Extraction of Corresponding Points Using EMSAC Algorithm (EMSAC을 이용한 대응점 추출 알고리즘에 관한 연구)

  • Wie, Eun-Young;Ye, Soo-Young;Joo, Jae-Hum;Nam, Ki-Gon
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.405-406
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    • 2006
  • This paper proposes the new algorithm for the extraction of the corresponding points. Our algorithm is based on RANSAC(Random Sample Consensus) with EM(Expectation-Maximization). In the procedure of RANSAC, N-points are selected by the result of EM instead of the random selection. EM+SAC algorithm is applied to the correspondence for the mosaicing.

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Pitch trajectories of English vowels produced by American men, women, and children

  • Yang, Byunggon
    • Phonetics and Speech Sciences
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    • v.10 no.4
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    • pp.31-37
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    • 2018
  • Pitch trajectories reflect a continuous variation of vocal fold movements over time. This study examined the pitch trajectories of English vowels produced by 139 American English speakers, statistically analyzing their trajectories using the Generalized Additive Mixed Models (GAMMs). First, Praat was used to read the sound data of Hillenbrand et al. (1995). A pitch analysis script was then prepared, and six pitch values at the corresponding time points within each vowel segment were collected and checked. The results showed that the group of men produced the lowest pitch trajectories, followed by the groups of women, boys, then girls. The density line showed a bimodal distribution. The pitch values at the six corresponding time points formed a single dip, which changed gradually across the vowel segment from 204 to 193 to 196 Hz. The normality tests performed on the pitch data rejected the null hypothesis. Nonparametric tests were therefore conducted to discover the significant differences in the values among the four groups. The GAMMs, which analyzed all the pitch data, produced significant results among the pitch values at the six corresponding time points but not between the two groups of boys and girls. The GAMMs also revealed that the two groups were significantly different only at the first and second time points. Accordingly, the methodology of this study and its findings may be applicable to future studies comparing curvilinear data sets elicited by experimental conditions.

Measurement of GMAW Bead Geometry Using Biprism Stereo Vision Sensor (바이프리즘 스테레오 시각 센서를 이용한 GMA 용접 비드의 3차원 형상 측정)

  • 이지혜;이두현;유중돈
    • Journal of Welding and Joining
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    • v.19 no.2
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    • pp.200-207
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    • 2001
  • Three-diemnsional bead profile was measured using the biprism stereo vision sensor in GMAW, which consists of an optical filter, biprism and CCD camera. Since single CCD camera is used, this system has various advantages over the conventional stereo vision system using two cameras such as finding the corresponding points along the horizontal scanline. In this wort, the biprism stereo vision sensor was designed for the GMAW, and the linear calibration method was proposed to determine the prism and camera parameters. Image processing techniques were employed to find the corresponding point along the pool boundary. The ism-intensity contour corresponding to the pool boundary was found in the pixel order and the filter-based matching algorithm was used to refine the corresponding points in the subpixel order. Predicted bead dimensions were in broad agreements with the measured results under the conditions of spray mode and humping bead.

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