• Journal of the Korean Society for Precision Engineering
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• 제20권4호
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• pp.174-182
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• 2003

Recently, medical imaging has taken interest on CAD based solution for anatomical part fabrication or finite element analysis of human body. In principle, contours representing object boundary are obtained through image processing techniques. Surface models are then approximated by a skinning method. For this, various methods should be applied to medical images and contours. The major bottleneck of the reconstruction is to remove shape inconsistency between contours and to generate the branching surface. In order to solve these problems, bi-directional smoothing and the composite contour generation method are proposed. Bi-directional smoothing has advantage of removing the shape inconsistency between contours and minimizing shrinkage effect with a large number of iterations. The composite contour by the proposed method ensures smooth transition in branching region.

• Proceedings of the KSRS Conference
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.54-58
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• 2002

Mean curvature diffusion (MCD) is a selective smoothing technique that promotes smoothing within a region instead of smoothing across boundaries. By using mean curvature diffusion, noise is eliminated and edges are preserved. In this paper, we propose methods of automatic parameter selection and implementation for the MCD model coupled to min/max flow. The algorithm has been applied to high resolution aerial images and the results show that noise is eliminated and edges are preserved after removal of noise.

• Journal of the Korea Society of Computer and Information
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• 제10권5호
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• pp.333-342
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• 2005

This paper proposes a method, which recognizes student's identification card by using image processing and recognition technology and can manage student information on the web. The presented scheme sets up an average brightness as a threshold, based on the brightest Pixel and the least bright one for the source image of the ID card. It is converting to binary image, applies a horizontal histogram, and extracts student number through its location. And, it removes the noise of the student number region by the mode smoothing with 3$\times$3 mask. After removing noise from the student number region, each number is extracted using vertical histogram and normalized. Using the enhanced ART1 algorithm recognized the extracted student number region. In this study, we propose the enhanced ART1 algorithm different from the conventional ART1 algorithm by the dynamical establishment of the vigilance parameter. which shows a tolerance limit of unbalance between voluntary and stored patterns for clustering. The Experiment results showed that the recognition rate of the proposed ART1 algorithm was improved much more than that of the conventional ART1 algorithm. So, we develop an educational matters administration system by using the proposed recognition method of the student's identification card.

• Journal of Advanced Marine Engineering and Technology
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• 제28권4호
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• pp.587-592
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• 2004

Pixel classification is one of basic issues of image processing. The general characteristics of the pixels belonging to various classes are discussed and the radical principles of pixel classification are given. At the same time, a pixel classification scheme based on image information scales is proposed. The proposed method is overcome that computation amount become greater and contents easily get turned. And image directional scales has excellent anti-noise performance. In the result of experiment. good efficiency is showed compare with other methods.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.65-70
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• 2009

In this paper a hybrid grid generation program for general 2-D region is introduced. The program is developed by using JAVA programming language, and it can be used either as an application program on a local computer or as an applet in the network environment. The hybrid grid system for a 2-D problem means a combination of triangular cells and quadrilateral cells, and it can offer both of the high flexibility of triangular cells and the high accuracy and efficiency of structured-type quadrilateral cells. To accommodate a quadrilateral-cell region and a triangular-cell region into one computational domain, it is importance to take good care of the interface between two different regions so that overall good grid quality can be maintained. In this research advancing layer method(ALM) augmented by elliptic smoothing method is used for the quadrilateral-cell region and advancing front method(AFM) is used for the triangular-cell region. A special treatment technique for the interface between those two regions is also developed. The interface treatment technique is basically to prevent the propagation of small cell size due to ALM method into the triangular region and maintain the smooth transition of cell-size scale between two different regions. By applying current technique high-quality hybrid grids for general 2-D regions can be easily generated, and typical grid generation results and flow solutions are demonstrated.

• Journal of the Institute of Electronics Engineers of Korea SD
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• 제41권2호
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• pp.9-15
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• 2004

We present a new unified analytical front surface potential model, which can accurately describe the transitions between the partially-depleted (PD) and the fully-depleted (FD) regimes with an analytical expression for the critical voltage V$_{c}$ delineating the PD and the FD region. It is valid in all regions of operation (from the sub -threshold to the strong inversion) and has the shorter calculation time than the iterative procedure approach. A charge sheet model based on the above explicit surface potential formulation is used to derive a single formula for the drain current valid in all regions of operation. Most of the secondary effects can be easily included in the charge sheet model and the model accurately reproduces various numerical and experimental results. No discontinuity in the derivative of the surface potential is found even though three types of smoothing functions are used. More importantly, the newly introduced parameters used in the smoothing functions do not strongly depend on the process parameter.

• Journal of Digital Contents Society
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• 제18권8호
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• pp.1603-1613
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• 2017

This paper proposes a method for effectively segmenting the hand region using a widely popular RGB color-based webcam. This performs the empirical preprocessing method four times to remove the noise. First, we use Gaussian smoothing to remove the overall image noise. Next, the RGB image is converted into the HSV and the YCbCr color model, and global fixed binarization is performed based on the statistical value for each color model, and the noise is removed by the bitwise-OR operation. Then, RDP and flood fill algorithms are used to perform contour approximation and inner area fill operations to remove noise. Finally, ROI (hand region) is selected by eliminating noise through morphological operation and determining a threshold value proportional to the image size. This study focuses on the noise reduction and can be used as a base technology of gesture recognition application.

• Communications for Statistical Applications and Methods
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• 제4권2호
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• pp.445-452
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• 1997

In this paper, twicing technique for the improvement of asymptotic boundary bias in nonparametric regression is considered. Asymptotic mean squared errors of the nonparametric regression estimators are derived at the boundary region by twicing the Nadaraya-Waston and local linear smoothing. Asymptotic biases of the resulting estimators are of order$h^2$and$h^4$ respectively.

• The Transactions of the Korea Information Processing Society
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• 제7권1호
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• pp.313-320
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• 2000

PEM algorithm cannot expend repeated algorithm, if penalty function is transcendental function. However, OSL algorithm has an advantage that repeated algorithm is easily derived, even though penalty function which has a complicated transcendental function. In spite of this advantage, this algorithm is restricted in convergence region of smoothing constant which increase penalized log-likelihood, so we cannot get the optimal image restoration because it cannot provide us with a various smoothing constant value for the digital image restoration. In this paper, in order to resolve the disadvantage of OSL algorithm, we would like to suggest the algorithm with smoothing constant enlarge the tolerance limit range of convergence and to find not only properties of its convergence but also usefulness of suggested algorithm through digital image simulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.75-78
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• 2004

A mesh generation algorithm adapted to the mesh density map using the Delaunay mesh generation technique is developed. In the finite element analyses of the forging processes, the numerical error increases as the process goes on because of discrete property of the finite elements or severe distortion of elements. Especially, in the region where stresses and strains are concentrated, the numerical discretization error will be highly increased. However, it is too time consuming to use a uniformly fine mesh in the whole domain to reduce the expected numerical error. Therefore, it is necessary to construct locally refined mesh at the region where the error is concentrated such as at the die corner. In this study, the point insertion algorithm is used and the mesh size is controlled by moving nodes to optimized positions according to a mesh density map constructed with a posteriori error estimation. An optimization technique is adopted to obtain a good position of nodes. And optimized smoothing techniques are also adopted to have smooth distribution of the mesh and improve the mesh element quality.