• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.69-76
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• 1998

Due to the drastic improvement of computer hardware and operating system, it is easy to break through the main defects of limited computer memory and processing time, etc. To keep up with this situation, this paper is focused on developing the preprocessor program with the input method based on vector graphic editor and the preprocessing technique including automatic node generation algorithm for the $\rho$-version finite element program. To develop this preprocessor program, the special data structure and the OOP(Object Oriented Programming) have been used by the Visual Basic 4.0. The Special data structure is proposed to describe the geometric data of node numberings and coordinates suitable for the $\rho$-version finite element program, which are quite different from the comvential h-version finite element program.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.9
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• pp.3177-3195
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• 2014

In many moving object detection problems of an aerial video, accurate and robust stabilization is of critical importance. In this paper, a novel accurate image alignment algorithm for aerial electronic image stabilization (EIS) is described. The feature points are first selected using optimal derivative filters based Harris detector, which can improve differentiation accuracy and obtain the precise coordinates of feature points. Then we choose the Delaunay Triangulation edges to find the matching pairs between feature points in overlapping images. The most "useful" matching points that belong to the background are used to find the global transformation parameters using the projective invariant. Finally, intentional motion of the camera is accumulated for correction by Sage-Husa adaptive filtering. Experiment results illustrate that the proposed algorithm is applied to the aerial captured video sequences with various dynamic scenes for performance demonstrations.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.205-214
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• 2009

This paper investigates stereo 3D viewing for linear pushbroom satellite images using the Orbit-Attitude Model proposed by Kim (2006) and using OpenGL graphic library in Digital Photogrammetry Workstation. 3D viewing is tested with KOMPSAT-2 satellite stereo images, a large number of GCPs (Ground control points) collected by GPS surveying and orbit-attitude sensor model as a rigorous sensor model. Comparison is carried out by two accuracy measurements: the accuracy of orbit-attitude modeling with bundle adjustment and accuracy analysis of errors in x and y parallaxes. This research result will help to understand the nature of 3D objects for high resolution satellite images, and we will be able to measure accurate 3D object space coordinates in virtual or real 3D environment.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.633-636
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• 2010

본 논문에서 Pan, Tilt 카메라를 이용한 객체 추적을 위하여 초기 지역정보를 이용하여 객체를 검출하고 검출된 객체의 색 정보를 이용하여 능동 객체를 추적하는 기술을 제안한다. 외부 환경의 잡음을 제거하기 위해 적응적인 가우시안 혼합 모델링을 이용하여 배경과 객체를 분리한다. 객체가 정해지면 카메라가 이동하는 동안에도 추적이 가능한 CAMShift 추적 알고리즘을 이용하여 객체를 실시간으로 추적한다. CAMShift 추적 알고리즘은 객체의 크기를 계산하므로 객체의 크기가 변하더라도 유동적인 객체 판별이 가능하다. Pan, Tilt의 위치는 구좌표계(Spherical coordinates system)를 이용하여 계산하였다. 이렇게 구해진 Pan, Tilt 위치는 Pan, Tilt 프로토콜을 이용하여 객체의 위치를 화면의 중심에 놓이게 함으로써 적합한 추적을 가능하게 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.229-230
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• 2022

본 논문에서는 CNN Object Detection과 더불어 3D 카메라 기반 디지털 좌표 인식 기술을 제안한다. 이 기술은 3D Depth Camera인 Intel 사의 Realsense D455를 이용해 대상을 감지하고 분류하며 대상의 위치를 파악한다. 또한 이 기술은 기존의 Depth Camera 내장 거리와는 다르게 좌표를 인식하여 좌표간의 거리까지 계산이 가능하다. 또한 Tensorflow SSD 구조와의 메모리 공유를 통해 시스템의 자원 낭비를 줄이며, 속도를 높이는 멀티쓰레드를 탑재했다. 본 기술을 통해 좌표간의 거리를 계산함으로써 스포츠, 심리, 놀이, 산업 등 다양한 환경에서 활용할 수 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.151-160
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• 1994

Recently, terrestrial photogrammetry has been applied effectively to data acquisition in GIS and to monitoring precise machinery for simulation test. Because 3-D coordinates of many object points can be quickly measured with constant accuracy and easy modeling by this method. In this study, the composition concerned with multi-camera system which simultaneously analyzes structure from multi-station using various cameras was developed. The errors of results were analyzed to investigate the accuracy of the system, error of unknown points and control points, convergent and strip adjustment for optimal network design also. As results of this study, the efficiency of multi-camera system developed here was proved through application to monitoring the entire area of the precise model ship. We could also acquire 3-dimensional coordinates with good accuracy by arranging pass points. Therefore, possibility of measurement of instantaneous deformation as well as precision analysis of structures can be suggested.

• Journal of the Ergonomics Society of Korea
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• v.34 no.6
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• pp.583-595
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• 2015

Objective: The purpose of this study was to determine the reliability of lower limb joint angles computed with the software ImageJ during jumping movements. Background: Kinematics is the study of bodies in motion without regard to the forces or torques that may produce the motion. The most common method for collecting motion data uses an imaging and motion-caption system to record the 2D or 3D coordinates of markers attached to a moving object, followed by manual or automatic digitizing software. Above all, passive optical motion capture systems (e.g. Vicon system) have been regarded as the gold standards for collecting motion data. On the other hand, ImageJ is used widely for an image analysis as free software, and can collect the 2D coordinates of markers. Although much research has been carried out into the utilizations of the ImageJ software, little is known about their reliability. Method: Seven healthy female students participated as the subject in this study. Seventeen reflective markers were attached on the right and left lower limbs to measure two and three-dimensional joint angular motions. Jump performance was recorded by ten-vicon camera systems (250Hz) and one digital video camera (240Hz). The joint angles of the ankle and knee joints were calculated using 2D (ImageJ) and 3D (Vicon-MX) motion data, respectively. Results: Pearson's correlation coefficients between the two methods were calculated, and significance tests were conducted (${\alpha}=1%$). Correlation coefficients between the two were over 0.98. In Vicon-MX and ImageJ, there is no systematic error by examination of the validity using the Bland-Altman method, and all data are in the 95% limits of agreement. Conclusion: In this study, correlation coefficients are generally high, and the regression line is near the identical line. Therefore, it is considered that motion analysis using ImageJ is a useful tool for evaluation of human movements in various research areas. Application: This result can be utilized as a practical tool to analyze human performance in various fields.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.4
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• pp.123-131
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• 1983

It is a matter of great importance that the elements of error in measurements be minimized in various surveying methods. It is also essential in photogrammetry to reduce the errors of ground control coordinates as their influence on the accuracy of the results is enormous, especially when the object distance is increased. In this paper, the techniques of surveying and photogrammetry were appropriately combined to obtain three-dimentional coordinates of considerable accuracy. By observing only the related angles with theodolite were obtained to prove its effectiveness. The major advantage of the presented method is its simplicity and accuracy as only the measurements by theodolite is required.

• Journal of Korea Multimedia Society
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• v.17 no.7
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• pp.818-828
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• 2014

After emerging of Microsoft Kinect, the interest in three-dimensional (3D) depth image was significantly increased. Depth image data of an object can be converted to 3D coordinates by simple arithmetic calculation and then can be reconstructed as a 3D model on computer. However, because the surface coordinates can be acquired only from the front area facing Kinect, total solid which has a closed surface cannot be reconstructed. In this paper, 3D registration method for multiple Kinects was suggested, in which surface information from each Kinect was simultaneously collected and registered in real time to build 3D total solid. To unify relative coordinate system used by each Kinect, 3D perspective transform was adopted. Also, to detect control points which are necessary to generate transformation matrix, 3D randomized Hough transform was used. Once transform matrices were generated, real time 3D reconstruction of various objects was possible. To verify the usefulness of suggested method, human arms were 3D reconstructed and the volumes of them were measured by using four Kinects. This volume measuring system was developed to monitor the level of lymphedema of patients after cancer treatment and the measurement difference with medical CT was lower than 5%, expected CT reconstruction error.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.3
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• pp.115-125
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• 2011

The smartphones which have been recently are embedded with high resolution quality camera, assisted GPS, accelerometer, gyroscope and various sensors including magnetometer sensor that could be directly used for measurement. This study aims to suggest the possible application of smartphone camera providing high resolution images in terms of photogrammetry by calibrating it and assessing its accuracy. First of all, prior to the accuracy assessment of smartphone camera, camera calibration was conducted to correct lens distortion of each camera and the accuracy of image coordinates and object coordinates calculated by bundle adjustment during this procedure was analyzed. Also regarding three-dimensional positioning, result analysis depending on considering lens distortion coefficients was conducted, and finally relative accuracy of smartphone camera on metric camera was assessed. The result showed that in terms of distortion correction of smartphone camera, also higher order symmetric radial lens distortion coefficients should be considered, and three dimensional position determined by smartphone images was a little difference from that by metric camera. Therefore it is expected that smartphone images have huge possibility to be used for photogrammetry.