• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.4
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• pp.267-277
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• 2019

Photogrammetry and computer vision are identical in determining the three-dimensional coordinates of images taken with a camera, but the two fields are not directly compatible with each other due to differences in camera lens distortion modeling methods and camera coordinate systems. In general, data processing of drone images is performed by bundle block adjustments using computer vision-based software, and then the plotting of the image is performed by photogrammetry-based software for mapping. In this case, we are faced with the problem of converting the model of camera lens distortions into the formula used in photogrammetry. Therefore, this study described the differences between the coordinate systems and lens distortion models used in photogrammetry and computer vision, and proposed a methodology for converting them. In order to verify the conversion formula of the camera lens distortion models, first, lens distortions were added to the virtual coordinates without lens distortions by using the computer vision-based lens distortion models. Then, the distortion coefficients were determined using photogrammetry-based lens distortion models, and the lens distortions were removed from the photo coordinates and compared with the virtual coordinates without the original distortions. The results showed that the root mean square distance was good within 0.5 pixels. In addition, epipolar images were generated to determine the accuracy by applying lens distortion coefficients for photogrammetry. The calculated root mean square error of y-parallax was found to be within 0.3 pixels.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.3
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• pp.235-240
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• 2011

A flexible hose attached to a mother ship experiences various motions that depend on the movement of the mother ship and that of underwater vehicle. Although the motion of the hose is a very important factor that determines how a mother ship should be steered in a real situation, it is difficult to experimentally obtain information about the hose motion. Therefore, we study the motion of the hose analytically. The ANCF(absolute nodal coordinate formulation) was used to model the hose, because this formulation can relax the Euler-Bernoulli theory and the Timoshenko beam theory and allow the deformation of the cross section. The mother ship is assumed to be a rigid body with 6 degrees of freedom. The motion of the hose is predominantly affected by the behavior of the mother ship and by the fluid flow.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5385-5391
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• 2013

As on-line purchases is activated, customers' demand increases for the realistic and accurate digital information of a product design. In this paper, we propose a practical method that can generate a realistic 3D model of a real product using a 3D geometry obtained by a 3D scanner and its photographic images. In order to register images to the 3D geometry, the camera focal length, the CCD scanning aspect ratio and the transformation matrix between the camera coordinate and the 3D object coordinate must be determined. To perform this 2D-3D registration with consideration of computational complexity, a three-step method is applied, which consists of camera calibration, determination of a temporary optimum translation vector (TOTV) and nonlinear optimization for three rotational angles. A case study for a metallic coated industrial part, of which the colour appearance is hardly obtained by a 3D colour scanner has performed to demonstrate the effectiveness of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.589-596
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• 2011

Picture Quality Improvement Systems(PQIS) have been developed for user's needs with the development of display technology. Most PQIS change the all input data, so there were some color distortion. In order to compensate such problems, the PQIS using Skin Protection Algorithm(SPA) have been proposed. But the PQIS using SPA is performed simplex color emphasis, as a result occurred color saturation and decoloration. In this paper, we proposed the modified PQIS using SPA on CIE 1976 u'v' chromaticity coordinate. The modified method operated chromaticity extension and reduction at the same time about brightness value to prevent the saturation and decoloration. We evaluated by comparing the conventional method with the proposed method of RGB Gamut variation rate using 42 test image.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.195-203
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• 2021

This study is about building an exercise training system that analyzes images taken of a person's whole body and displays the normal operating range for user-specific movements as images. This study analyzes the front and side of the user's body based on the standing point, sets the node in the joint position of the human body, and places the node in the spatial coordinate system from the point of entry, and calibrates the normal node operating range according to the set standard node coordinate. Therefore, the method of the study presented a method to select differentiation from this study through prior technical research and literature research, and the purpose of the study is to establish a exercise training system accordingly.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.587-588
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• 2022

In this paper, we propose a rigid body tracking method in 3D space using 2D passive marker images from multiple motion capture cameras. First, a calibration process using a chess board is performed to obtain the internal variables of individual cameras, and in the second calibration process, the triangular structure with three markers is moved so that all cameras can observe it, and then the accumulated data for each frame is calculated. Correction and update of relative position information between cameras. After that, the three-dimensional coordinates of the three markers were restored through the process of converting the coordinate system of each camera into the 3D world coordinate system, the distance between each marker was calculated, and the difference with the actual distance was compared. As a result, an error within an average of 2mm was measured.

• Proceedings of the KWS Conference
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• 1993.05a
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• pp.21-24
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• 1993

• 한국지형공간정보학회:학술대회논문집
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• 1994.04a
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• pp.1-13
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• 1994

• Proceedings of the Korean Vacuum Society Conference
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• 1996.02a
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• pp.103-103
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• 1996

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05b
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• pp.653-658
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• 2001