• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.2
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• pp.149-159
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• 2001

The conventional block-based motion prediction suffers, especially in low bit-rate video application, from shortcomings such as blocking artifacts of motion field and unstable motion estimation. To overcome the deficiency, this paper proposes one method of adopting a new motion compensation scheme based on the irregular triangular mesh structure while keeping the current block-based DCT coding structure of H.263 as much as possible. To represent the reconstructed previous frame using minimal number of control points, the proposed method designs content-adaptive irregular triangular meshes, and then, estimate the motion vector of each control point using the affine transformation-based matching. The predicted current frame is obtained by applying the affine transformation to each triangular mesh. Experiment with the several real video sequences shows improvement both in objective and subjective picture quality over the conventional block-based H.263 method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.28-40
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• 1991

Affine transformation was used to analyze the bending, buckling and vibration behaviors of a thick antisymmetric angle-ply rectangular simply supported laminate. Introducing the generalized parameters, the comprehensive solutions are found. The generalized parameters are a generalized rigidity ratio ( $D^*1), a generalized Poisson's ratio (.epsilon.) and a principal rigidity ratio (.alpha.). Hence, the transverse deflection decreases, the uniaxial buckling load and the fundamental frequency increase with increasing $D^*1 and decreasing .alpha., but the effect of .epsilon. is negligible. With decreasing the thickness ratio, the results by the classical plate theory are more erroneous. The transverse deflection is minimum, the uniaxial buckling load and the fundamental frequency are maximum if the fiber angle is 45.deg., and number of plies is more than 4. The time and efforts can be saved to understand the behaviors of composite laminates because these results can be applied to another composite material easily.sily.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.691-700
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• 1995

Most fractal image codings using fractal concept require long encoding time because a large amount of computation is needed to find an optimal affine transformation point. Such a problem can be solved by designing a block classifier fitted to characteristics of image blocks. In general, it is possible to predict more precise and various types of blocks in frequency domain than in spatial domain. In this paper, we propose a block classifier to predict the block type using characteristics of DCT(Discrete Cosine Transform). This classifier has merits to enhance the quality of decoded images as well as to reduce the encoding time meeting fractal features. AC coefficient values in frequency domain make it possible to predict various types of blocks. As the results, the number of comparisons between a range block and the correspoding domain blocks to reach an optimal affine transformation point can be reduced. Specially, signs of DCT coefficients help to find the optimal affine transformation point with only two isometric transformations by eliminating unnecessary isometric transformations among eight isometric transformations used in traditional fractal codings.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1894-1905
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• 1996

Delauuany triangulation which is the dual of Dirichlet tessellation is not affine invariant. In other words, the triangulation is dependent upon the choice of the coordinate axes used to represent the vertices. In the same reason, Delahanty tetrahedrization does not have an affine iveariant transformation property. In this paper, we present a new type of tetrahedrization of spacial points sets which is unaffected by translations, scalings, shearings and rotations. An affine invariant tetrahedrization is discussed as a means of affine invariant 2 -D triangulation extended to three-dimensional tetrahedrization. A new associate norm between two points in 3-D space is defined. The visualization of the structure of tetrahedrization can discriminate between Delaunay tetrahedrization and affine invariant tetrahedrization.

• Bulletin of the Korean Mathematical Society
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• v.7 no.1
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• pp.27-34
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• 1970

• Proceedings of the Korea Water Resources Association Conference
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• 1995.05a
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• pp.481-487
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• 1995

• Spatial Information Research
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• v.11 no.4
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• pp.481-491
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• 2003

This study aims at generating a continuous map by coordinates transformation between cadastral maps with different surveying origins. The continuous cadastral map is useful in various fields of GIS. For this purpose, an experimental study was conducted at Osan-Si, Kyonggi Province in cooperation with related institutions. In this study, three control point zone, large, medium, and small zone were to!;ted. For each control point, the currently used data were compared with the data at the surveyed time. About coordinate transformation method, we tested Helmert, Affine, and Polynomial methods which are the most representative among 2-dimensional coordinate transformations. These three transformation methods were evaluated according to variation of transformed parcel shape and agreement with neighboring areas. As the result of the evaluation, Affine transformation in large zone is the most appropriate coordinate transformation method fer Osan-Si.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.603-608
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• 2011

Since PTV (particle tracking velocimetry) provides velocity vectors by tracking each particle in a fluid flow, it has significant benefits when used for nano- and bio-fluid flows. However, PTV has only been used for limited flow fields because interpolation data loss is inevitable in PTV in principle. In this paper, a hybrid particle image velocimetry (PIV) algorithm that eliminates interpolation data loss was constructed by using an affine transformation. For the evaluation of the performance of the constructed hybrid PIV algorithm, an artificial image test was performed using Green-Taylor vortex data. The constructed algorithm was tested on experimental images of the wake flow (Re = 5,300) of a rectangular body ($6cm\;{\times}3cm$), and was demonstrated to provide excellent results.

• Journal of the Korean Society of Visualization
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• v.20 no.1
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• pp.11-17
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• 2022

Among the various factors that cause the performance decrease of heat exchangers used in many industries, flow path blocking is one of the important and serious factor. In order to solve this problem, proper maintenance and management of the heat exchanger is important and emphasized. In this study, we developed and algorithm that can quantitatively determine and diagnose the normal and blocked areas of fin-tube heat exchanger using pattern analysis, Gaussian Edge Detection, Image Processing and Affine Transformation techniques. The developed algorithms was applied to the actual heat exchanger and the performance was evaluated by comparing with the manual results. From these results, it was proved that the developed algorithm is effective in evaluating the pollution ratio of the fin-tube heat exchanger.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.281-288
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• 2009

In the paper, we try to develop the methodology for updating road networks of large-scale digital maps by using construction drawing data. For the purpose, it is pre-requite step to merge road networks detached in CAD drawing data. As such, tie points are identified in neighboring drawings and used for solving the parameters of 2D conformal transformation between drawings. Then, the merged road network in CAD data is transformed to the coordinate system of digital maps. In the process, IPs in the drawings are considered as control information and 2D affine transformation is selected for coordinate transformation. Through the experiments with real dataset, we can identify that the developed method is valid and generally applicable.