• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.104-108
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• 2010

We proposed an axis transformation technique which reveals a distance parameter directly from optical scanning holography (OSH). After synthesis of a real-only spectrum hologram and power fringe adjusted filtering, we transform an original frequency axis to a new frequency axis using interpolation. In the new frequency axis, the filtered hologram has a single frequency which is linearly proportional to the distance parameter. Thus, the inverse Fourier transformation of the filtered hologram gives a delta function pair in the new spatial axis. Finally, we extract the distance parameter by detecting the location of the delta function pair.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.50-52
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• 2002

Distance relays need accurate current and voltage for determining the trip ignition. Therefore we must analyze nonlinear phenomena which cause distortion in signals first of all. This paper presents the effect of some distortion(arcing fault and current transformer saturation) in power system. The saturation of a current transformer distorts input current of a distance relay and arcing faults make current and voltage to be changed. This paper describes modeling methods of a current transformer and arcing faults, and describes the simulation result of two distance relay algorithms (discrete fourier transform and modified differential equation methods)

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2414-2433
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• 2019

The aim of this paper is to design a 3D laser radar prototype based on laser triangulation. The mathematical model of distance sensitivity is deduced; a pixel-distance conversion formula is discussed and used to complete 3D scanning. The center position extraction algorithm of the spot is proposed, and the error of the linear laser, camera distortion and installation are corrected by using the proposed weighted average algorithm. Finally, the three-dimensional analytic computational algorithm is given to transform the measured distance into point cloud data. The experimental results show that this 3D laser radar can accomplish the 3D object scanning and the environment 3D reconstruction task. In addition, the experiment result proves that the product of the camera focal length and the baseline length is the key factor to influence measurement accuracy.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.27 no.2
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• pp.146-159
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• 2023

This paper proposes a hybrid algorithm combining K-means clustering and watershed algorithms for flower segmentation and counting. We use the K-means clustering algorithm to obtain the main colors in a complex background according to the cluster centers and then take a color space transformation to extract pixel values for the hue, saturation, and value of flower color. Next, we apply the threshold segmentation technique to segment flowers precisely and obtain the binary image of flowers. Based on this, we take the Euclidean distance transformation to obtain the distance map and apply it to find the local maxima of the connected components. Afterward, the proposed algorithm adaptively determines a minimum distance between each peak and apply it to label connected components using the watershed segmentation with eight-connectivity. On a dataset of 30 images, the test results reveal that the proposed method is more efficient and precise for the counting of overlapped flowers ignoring the degree of overlap, number of overlap, and relatively irregular shape.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.2
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• pp.103-109
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• 2010

The edit distance problem is finding the minimum number of edit operations to transform a string into another one. It is one of the important problems in algorithm research and there are some algorithms that compute an optimal edit distance for the one-dimensional languages such as the English alphabet. However, there are a few researches to find the edit distance for the more complicated language such as the Korean or Chinese alphabet. In this paper, we define the measure of the edit distance for the Korean alphabet and present an algorithm for the edit distance problem for the Korean alphabet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.9
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• pp.785-795
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• 1990

For the far field radiation pattern of a microstrip array antenna which is conformed to a cylindrical surface and forms an arc array, an approximate analysis method using FOURIER TRANSFORM is presented. In this method, the conformal array antenna is projected on the effective aperture plane and assumed to be an aperiodic array with nonlinear phase tilt. The effective aperture plane includes four end-points of each arc on the cylindrical surface. When the effective aperture ratio which is normalized to the planar type is from 1.0 to 0.9, it is confirmed that this approximate method is valid. To the array on the effective aperture plane, it is assumed that the phase tilt is due to the distance between aperture plne and curvature surface. Specially, when the radius of arc is more than 5 times to its length, the FOURIER TRANSFORM METHOD could be used with only varying scale factors. The results of calculating by approximate method are good agreement with the results of COORDINATE TRANSFORM METHOD and experimentally measured value in the range of -40dB. And, the difference of half power angle is less than 5 degrees when the effective aperture ratio moer than 0.9.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.3
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• pp.39-47
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• 2000

In this paper, we propose a new method of finding the true length of the line and long axis of the ellipse at the $\theta$=$\theta$o＋ 90$^{\circ}$ and short axis of the ellipse at the $\theta$ = $\theta$o from the Hough transform (HT) results. Through the simulations, we showed that the true length of the line and ellipse could be obtained with 98 % accuracy by using the distance from the maximum envelope to the minimum envelope. To compare the simulation results with the experimental results, we performed optical experiments by using a HT CGH filter. Through the experiments, we showed that our results were very similar to those of the simulation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.4
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• pp.442-454
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• 2002

It's noticed that the SA-DCT (Shape-Adaptive Discrete Cosine Transform) produces different 2-dimensional transform coefficients according as the first 1-dimensional transform is applied in horizontal or vertical direction for an arbitrarily shaped boundary block. Performing the first 1-dimensional transform in the direction, which has higher spatial correlation or smaller shifting distance, can compact the energy on the smaller number of AC coefficients around DC. This paper shows, experimentally, the compaction capability improvement by choosing the first 1-dimensional transform direction with higher spatial correlation or smaller shifting distance. Two adaptive selection methods are proposed to decide efficiently the spatial direction with higher correlation in a boundary block. One is based on the gradients between DC coefficients of neighboring and current blocks, and the other is based on the final coding efficiency that means the number of bits required for coding the block. Using the MPEG-4 video coder, the proposed method shows coding efficiency gain up to 10.87% compared to the conventional SA-DCT method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.3104-3120
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• 2017

The intelligent monitoring system has been successfully applied in many fields such as: monitoring of production lines, transportation, etc. Smart surveillance systems have been developed and proven effective in some specific areas such as monitoring of human activity, traffic, etc. Most of critical application monitoring systems involve object tracking as one of the key steps. However, task of tracking of moving object is not easy. In this paper, the authors propose a method to implement human object tracking in outdoor environment based on human features in shearlet domain. The proposed method uses shearlet transform which combines the human features with context-sensitiveness in order to improve the accuracy of human tracking. The proposed algorithm not only improves the edge accuracy, but also reduces wrong positions of the object between the frames. The authors validated the proposed method by calculating Euclidean distance and Mahalanobis distance values between centre of actual object and centre of tracked object, and it has been found that the proposed method gives better result than the other recent available methods.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.295-300
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• 2005

We introduce an x-ray micro tomography system capable of high resolution imaging of a local region inside a small animal. By combining two kinds of projection data, one from a full field-of-view (FOV) scan of the whole body and the other from a limited FOV scan of the region of interest, we have obtained zoomed-in images of the region of interest without any contrast a nomalies. We have integrated a micro tomography system using a micro-focus x-ray source, a $1248\times1248$ flat-panel x-ray detector, and a precision scan mechanism. Using the cross-sectional images taken with the zoom-in micro tomography system, we measured trabecular thicknesses of femur bones in postmortem rats. To compensate the limited spatial resolution in the zoom-in micro tomography images, we used the fuzzy distance transform for the calculation of the trabecular thickness. To validate the trabecular thickness measurement with the zoom-in micro tomography images, we compared the measurement results with the ones obtained from the conventional micro tomography images of the extracted bone samples.