• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.33-39
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• 1999

In order to calculate geoidal height refered to Bessel ellipsoid, methods to translate geoidal heights from a certain coordinate system to an arbitrary system with the corresponding ellipsoid are studied. and geoidal heights refered to Bessel ellipsoid were computed from EGM96 Model refered to GRS80 using iteration method pro-posed in this paper. Transformation parameters between WGS84 and Bessel were calculated using geoidal heights computed from iteration method. The result of coordinate transformation(standard deviation) were 0.009 second in latitude and 0.006 in longitude and 0.393m in orthometric height.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.1
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• pp.61-70
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• 2004

In this paper, we propose the color-temperature conversion system with compensated X-chromaticity coordinate. It uses a linear regression to improve the error of color-temperatue calculation in conventional systems. It also extend the color-temperature range from 1,667K to 25,000K to Provide a wider color-temperature range. We show the effectiveness of the proposed method by comparing the performance of the proposed method with those of the Robertson's and the existing methods. The proposed method is experimetally verified by displaying the results on a TV system through the Xilinx FPGA XCV2000E-BG560.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10b
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• pp.448-452
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• 2006

본 논문에서는 특정 마커를 사용하는 실감형 증강현실 시스템 상에서 카메라가 비정형적인 움직임을 하는 경우에 대하여, 다중 마커를 사용한 떨림 현상을 줄인 실시간 움직임 추적 기법을 제안하고자 한다. 카메라의 움직임을 추정하기 위하여 카메라와 마커 사이의 변환을 계산해야 한다. 이미지로부터 검출된 각 마커의 네 모서리 점들을 이용하여, 각 마커에 대한 변환을 계산한다. 마커는 서로 다른 로컬 좌표계를 가지고 있고, 마커에 대한 변환은 해당 마커의 좌표계에 의해 정의된다. 다중 마커의 로컬 좌표계로부터 최적의 카메라 움직임을 추정하기 위한 정합 알고리즘을 제안한다. 정합을 위한 방법으로 레퍼런스 마커를 사용한다. 레퍼런스 마커는 정합 과정에서 자동적으로 선택된다. 레퍼런스 마커를 기준으로 각 마커의 변환에 대해 신뢰성(confidence rate)을 기반으로 가중치를 적용함으로써 최적의 카메라 움직임을 추정할 수 있다. 또한 추정된 카메라의 움직임의 최적화를 위하여 히스토리 버퍼를 사용하여 떨림 현상을 제거하는 방법을 제안한다. 추정된 카메라의 위치에 대한 평균 필터 및 중간 필터의 개념과 유사한 보정 방법을 통해 떨림 현상을 제거한다. 실험을 통해 다른 방법들과 비교한 우리가 제안한 방법의 정확성을 확인할 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 1989.07a
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• pp.123-132
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• 1989

자연하천에서의 흐름특성을 해석하기 위해 Boundary - fitted(BF) coordinate system을 응용하여 유한차분법에 의한 2차원모델을 개발하였다. BF coordinates는 경계면의 형상에 관계없이 적용할 수 있으며 모든 계산은 기본식의 좌표변환을 통해 직각좌표계에서 행해지므로 경계조건의 입력에 용이하다. Physical domain(X - Y 좌표계)에서 하천의 형상을 입력하면 Grid generation에 의해 모든 계산은 Computational domain($\varepsilon$ - n 좌표계)에서 행해진다. Computational domain에서의 유한차분법은 half - time step으로 ADI 방법을 이용했고, 한 방향의 유속과 수위를 Double sweep으로 풀었다. 유속, 수위 및 하상의 격점망은 Staggered grid system을 사용했으며 geometric elements는 각 격점별로 계산하였다. 본 모델을 이용하므로써 불규칙한 수로나 하천의 흐름상태를 해석할 수 있으므로 흐름의 종단, 횡단방향의 유속분포, Superelevation을 구할 수 있고 하천의 계획, 관리, 제방의 호안이나 구조물의 설치등으로 일어나는 수리학적 영향등을 예측할 수 있다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.373-379
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• 2019

In this study, image-based flock monitoring and density evaluation were conducted for broiler chicks welfare. Image data were captured by using a mono camera and region of broiler chicks in the image was detected using converting to HSV color model, thresholding, and clustering with filtering. The results show that region detection was performed with 5% relative error and 0.81 IoU on average. The detected region was corrected to the actual region by projection into ground using coordinate transformation between camera and real-world. The flock density of broiler chicks was estimated using the corrected actual region, and it was observed with an average of 80%. The developed algorithm can be applied to the broiler chicks house through enhancing accuracy of region detection and low-cost system configuration.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.189-192
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• 2001

In this paper, we desire to design real time image processing system to change a various chromaticity in HDTV that has 1344*806 resolution and requires a high-speed 65MHz operation. In order to change the image chromaticity, it is necessary to calculate the color temperature of the image. Conventional way of calculating the temperature uses 2-D algorithm [1] that requires bulky hardware. This paper propose a one-dimensional color-temperature conversion that reduces the hardware complexity while keeping the performance of the 2-D algorithm. The proposed method is realized by using the Xilinx Virtex FPGA XCV 2000E-6BG560.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.2
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• pp.119-126
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• 1996

TM projection is widely used for surveying and mapping. However, the complicated computations and process are required and, moreover. the different results of computation may occur according to different formulae and coefficients. In this study, the transformation formulae are classified into 4 categories and the computations are executed according to the categories. The computations are also made to different value of the circular constant, $\pi$. The result of test shows that the enough number of items in formular have to be used for precise computation and the circular constant has to calculate down the 13 places of decimals in order to obtain the precision of 1mm on the ground scale.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.869-876
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• 2017

Analysis of actuating forces and joint reaction forces are essential to determine the capacity of actuators, to control the mechanical system and to design its components. This paper presents an algorithm that calculates actuating forces(or torques), depending on the various types of driving constraints, in order to produce a given system motion in the joint coordinate space. The joint coordinates are used as the generalized coordinates of a kinematic system. System equations of motion and constraint acceleration equations are transformed from the Cartesian coordinate space to the joint coordinate space using the velocity transformation method. A numerical example is carried out to verify the algorithm proposed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.4
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• pp.315-324
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• 2022

The conventional LESS (LEast-Squares Solution) is calculated under the assumption that there is no errors in independent variables. However, the coordinates of a point, either from traditional ground surveying such as slant distances, horizontal and/or vertical angles, or GNSS (Global Navigation Satellite System) positioning, cannot be determined independently (and the components are correlated each other). Therefore, the TLS (Total Least Squares) adjustment should be applied for all applications related to the coordinates. Many approaches were suggested in order to solve this problem, resulting in equivalent solutions except some restrictions. In this study, we calculated the normal vector of the 3D plane determined by the trace of the VLBI targets based on TLS within GHM (Gauss-Helmert Model). Another numerical test was conducted for the estimation of the Helmert transformation parameters. Since the errors in the horizontal components are very small compared to the radius of the circle, the final estimates are almost identical. However, the estimated variance components are significantly reduced as well as show a different characteristic depending on the target location. The Helmert transformation parameters are estimated more precisely compared to the conventional LESS case. Furthermore, the residuals can be predicted on both reference frames with much smaller magnitude (in absolute sense).

• Spatial Information Research
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• v.22 no.1
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• pp.35-43
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• 2014

The Triangle Mesh Warping method is suggested and applied in coordinate transformation to world geodetic system in this study. The common points of Uiwang city are used to compare the transformation accuracy of the suggested methods with existing national coordinate transformation methods. As a result, the Triangle Mesh Warping method was satisfied with accuracy criteria for positioning on a map larger than scale 1/1,000 with smaller number of common points and without distortion modeling. Additionally, in case of Guri and Pyeongtaek city that established the World Geodetic System, the suggested method generates the result of transformation accuracy better than 5cm. Based on the test, it was found that the suggested method improves the problem of securing many common points and reduces the problem of mis-match between the transformed data of adjacent areas. Accordingly, for transformation of large-scale topographic map, cadastral map, GIS DB and serial cadastral map to the World Geodetic System, it is judged that the Triangle Mesh Warping would be a good method for economical efficiency and accuracy using by minimum common point.