• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.3
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• pp.43-52
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• 2003

The new principle to measure a sizing degree by a contact angle was developed using an automatic determination of the 3-end point coordinates of the water droplet on a sheet, which could diminish the operator's bias during measurement. A constant amount of water was first placed on a sample sheet by a water dispenser, and then an image of the liquid droplet was captured by a digital camera and then transmitted to a computer. The program measuring for contact angle extracted a liquid contour by Gaussian function combined with a 8-direction chain code. The Euclidean equation was applied to the binary image of the liquid contour in order to measure the diameter of the contour. Finally, the contact angle of the liquid was calculated by using the diameter and the top coordinates. In addition, a surface free energy of the sample sheet and an elapsed time taken up to the complete absorption into the sheet were simultaneously measured with the contact angle.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.7
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• pp.144-153
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• 1997

The inverse kinematics problem of a reclaimer which excavates and transports raw materials in a raw yard is investigated. Because of the geometric feature of the equipment in which scooping buckets are attached around the rotating disk, kinematic redundancy occurs in determining joint variable. Link coordinates are introduced following the Denavit-Hartenbery representation. For a given excavation point the forward kinematics yields 3 equations, however the number of involved joint variables in the equations is four. It is shown that the rotating disk at the end of the boom provides an extra passive degree of freedom. Two approaches are investigated in obtaining inverse kinematics solutions. The first method pre-assigns the height of excavation point which can be determined through path planning. A closed form solution is obtained for the first approach. The second method exploits the orthogonality between the normal vector at the excavation point and the z axis of the end-effector coordinate system. The geometry near the reclaiming point has been approximated as a plane, and the plane equation has been obtained by the least square method considering 8 adjacent points near the point. A closed form solution is not found for the second approach, however a linear approximate solution is provided.

• Journal of Cadastre & Land InformatiX
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• v.46 no.2
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• pp.183-196
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• 2016

Ground control points are needed for precision geometric correction of satellite images, and the coordinates of a high-quality ground control point can be obtained from the GPS measurement. However, considering the GPS measurement requires an excessive amount o f t ime a nd e fforts, there is a need for coming up with an alternative solution to replace it. Therefore, we examined the possibility of replacing the existing GPS measurement with coordinates available at online maps to acquire the coordinates of ground control points. To this end, we examined error amounts between the coordinates of ground control points obtained through Daum Map API, and them compared the accuracies between three types of coordinate transformation equations which were used for geometric correction of satellite images. In addition, we used the coordinate transformation equation with the highest accuracy, the coordinates of ground control point obtained through the GPS measurement and those acquired through D aum M ap A PI, and conducted geometric correction on them to compare their accuracy and evaluate their effectiveness. According to the results, the 3rd order polynomial transformation equation showed the highest accuracy among three types of coordinates transformation equations. In the case of using mid-resolution satellite images such as those taken by Landsat-8, it seems that it is possible to use geometrically corrected images that have been obtained after acquiring the coordinates of ground control points through Daum Map API.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.54-61
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• 2022

Ship is a huge system including a variety of pipe arrangements. Pipes are installed according to the design layout, however the end poistion of pipes are not well matched owing to its measurement and construction errors. In this situation, the customized pipe fitting is frequently designed to connect with both pipes, the position of which are manually measured. This paper focused that these two coordinates are measured by point cloud from RGBD sensor and the relative transformation induced by positional and orientational differences is calculated by inverse kinematics in robotics theory. Therefore, the result applies for the methodology of the pipe connection design. The pipe coordinate that is estimated by the matching and the probabilistic RANSAC method will be verified by experiments. The kinematic design parameters are computationally calculated by using the minimum degree of freedom that connects both pipe coordinates.

• Journal of Biomedical Engineering Research
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• v.35 no.3
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• pp.50-54
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• 2014

It is being tried to control robot arm using brain signal in the field of brain-machine interface (BMI). This study is focused on applying guidance laws for efficient robot arm control using 3D coordinates obtained from Magnetoencephalography (MEG) signal which represents movement of upper limb. The 3D coordinates obtained from brain signal is inappropriate to be used directly because of the spatial difference between human upper limb and robot arm's end-effector. The spatial difference makes the robot arm to be controlled from a third-person point of view with assist of visual feedback. To resolve this inconvenience, guidance laws which are frequently used for tactical ballistic missile are applied. It could be applied for the users to control robot arm from a first-person point of view which is expected to be more comfortable. The algorithm which enables robot arm to trace MEG signal is provided in this study. The algorithm is simulated and applied to 6-DOF robot arm for verification. The result was satisfactory and demonstrated a possibility in decreasing the training period and increasing the rate of success for certain tasks such as gripping object.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.3 s.21
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• pp.53-59
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• 2002

Territorial sea baseline is a borderline, with the effectuation of the United Nations Convention on the Law of the Sea of 1982, for the related sea zone negotiations with neighboring countries. Its position must be determined to international standard like WGS84 coordinate system. In this study, GPS survey for territorial sea points was performed to determine territorial baseline around five islands in the yellow sea, and the results of them were compared with previous coordinates. Territorial sea point, outermost spot of a nation's realm, tend to be placed in end up low-tide elevations or precipice. Therefore traditional surveying methods are hard to take accurate observations, so that GPS survey is most effective. Through the study, the scientific and reasonable methods for GPS surveying procedure is presented. The results of coordinate comparison show that there are wide difference between the old and new coordinates, and it is necessary for the whole area of islands to calculate displacements by GPS surveying.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.4
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• pp.301-310
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• 2013

The aim of the present study is to enhance query speed of large 3D point cloud indexed in octree by parallel query using multi-cores. Especially, it is focused on developing methods of accessing multiple leaf nodes in octree concurrently to query points residing within a radius from a given coordinates. To the end, two parallel query methods are suggested using different strategies to distribute query overheads to each core: one using automatic division of 'for routines' in codes controlled by OpenMP and the other considering spatial division. Approximately 18 million 3D points gathered by a terrestrial laser scanner are indexed in octree and tested in a system with a 8-core CPU to evaluate the performances of a non-parallel and the two parallel methods. In results, the performances of the two parallel methods exceeded non-parallel one by several times and the two parallel rivals showed competing aspects confronting various query radii. Parallel query is expected to be accelerated by anticipated improvements of distribution strategies of query overhead to each core.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.6
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• pp.625-635
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• 2014

Multiple strips are required for large area mapping using ALS (Airborne Laser Scanner) system. LiDAR (Light Detection And Ranging) data collected from the ALS system has discrepancies between strips due to systematic errors of on-board laser scanner and GPS/INS, inaccurate processing of the system calibration as well as boresight misalignments. Such discrepancies deteriorate the overall geometric quality of the end products such as DEM (Digital Elevation Model), building models, and digital maps. Therefore, strip adjustment for minimizing discrepancies between overlapping strips is one of the most essential tasks to create seamless point cloud data. This study implemented area-based matching (ABM) to determine conjugate features for computing 3D transformation parameters. ABM is a well-known method and easily implemented for this purpose. It is obvious that the exact same LiDAR points do not exist in the overlapping strips. Therefore, the term "conjugate point" means that the location of occurring maximum similarity within the overlapping strips. Coordinates of the conjugate locations were determined with sub-pixel accuracy. The major drawbacks of the ABM are sensitive to scale change and rotation. However, there is almost no scale change and the rotation angles are quite small between adjacent strips to apply AMB. Experimental results from this study using both simulated and real datasets demonstrate validity of the proposed scheme.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.42-47
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• 2017

In the distribution of digital image, the median filtering is used for a forgery. This paper proposed the algorithm of a image forensics detection for the classification of median filtering. For the solution of this grave problem, the feature vector is composed of 42-Dim. The detected quantity 32, 64 and 128 of forgery image edges, respectively, which are processed by the Hough transform, then it extracted from the start-end point coordinates of the Hough Lines. Also, the Hough Peaks of the Angle-Distance plane are extracted. Subsequently, both of the feature vectors are composed of the proposed scheme. The defined 42-Dim. feature vector is trained in SVM (Support Vector Machine) classifier for the MF classification of the forged images. The experimental results of the proposed MF detection algorithm is compared between the 10-Dim. MFR and the 686-Dim. SPAM. It confirmed that the MF forensic classification ratio of the evaluated performance is 99% above with the whole test image types: the unaltered, the average filtering ($3{\times}3$), the JPEG (QF=90 and 70)) compression, the Gaussian filtered ($3{\times}3$ and $5{\times}5$) images, respectively.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.99-108
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• 2013

The purpose of this study was to analyze the kinematic characteristics of javelin to compare the characteristics between world elite athletes and local male athletes. The subjects selected 9 athletes out of total 13 athletes recorded more than 65 m in the preliminary and main competition participated in the 93rd National Sports Festival held in 2012. Three-Dimensional motion analysis using a system of 4 video cameras(Sony HXR-MC2000) at a sampling frequency of 60 fields/s was performed for this study. The Kwon3D 3.1 was used to obtain the three dimensional coordinates about the top, grip, end of javelin. And the kinematic factors of javelin calculated using Matlab2009a program. The resultant speed of javelin that affects directly to the record of performance showed 26.08 m/s indicated lower speed of about 2-3 m/s than world elite athletes. The release point appeared to have been made at the high of $1.79{\pm}0.07$ m of 99.8% of the height of the athletes. In terms of release angle, it was indicated average $33.0{\pm}3.81^{\circ}$ lower release angle compared to the world elite athletes. The attitude angle(up & down tilt angle, X axis) related to javelin indicated average $38.5{\pm}4.96^{\circ}$, its related attack angle average $5.5{\pm}5.11^{\circ}$, and yaw angle(sideslip, side attack angle) average $15.7{\pm}8.48^{\circ}$.