• Journal of the Korean Society of Visualization
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• v.4 no.2
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• pp.59-68
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• 2006

We have evaluated the performances of the following six interpolation schemes used for win-dow deformation in particle image velocimetry (PIV): the linear, quadratic, B-spline, cubic, sinc, Lagrange interpolations. Artificially generated images comprised of particles of diameter in a range pixel were investigated. Three particle diameters were selected for detailed evaluation: pixel with a constant particle concentration $0.02particle/pixel^2$. Two flow patterns were considered: uniform and shear flows. The mean and random errors, and the computation times of the interpolation schemes were determined and compared.

• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1104-1113
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• 2000

This paper proposes an efficient reverse engineering technique for compound surfaces using a boundary detection method. This approach consists in extracting geometric edge information using a vision system, which can be used in order to drastically reduce geometric errors in the vicinity of compound surface boundaries. Through the image-processing technique and the interpolation process, boundaries are reconstructed by either analytic curves (e. g. circle, ellipse, line) or parametric curves (B-spline curve). In other regions, except boundaries, geometric data are acquired on CMM as points inspected using a touch type probe, and then they are interpolated on several surfaces using a B-spline skinning method. Finally, the boundary edge and the skinned surfaces are combined to reconstruct the final compound surface. Through simulations and experimental works, the effectiveness of the proposed method is confirmed.

• Journal of Mechanical Science and Technology
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• v.17 no.3
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• pp.336-342
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• 2003

Increasing demand on precision machining using computerized numerical control (CNC) machines have necessitated that the tool move not only with the smallest possible position error but also with smoothly varying feedrates in 3-dimensional (3D) space. This paper presents the simultaneous 3D machining process investigated using a retrofitted PC-NC milling machine. To achieve the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non Uniform Rational B-Spline (NURBS) curve is proposed. With this accurate and efficient algorithm for the generation of complex 3D shapes, a real-time NURBS interpolator was developed using a PC and the simultaneous 3D machining was accomplished satisfactorily.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.5
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• pp.89-94
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• 2002

Increasing demands on precision machining using CNC machines have necessitated that the tool to move with a position error as small as possible in 3-dimensional (3D) space. This paper presents the simultaneous 3D machining with a retrofitted PC-NC milling machine. To achieve the simultaneous 3-axis motions, a new precision interpolation algorithm for 3D Non-Uniform Rational B-Spline(NURBS) curve is used. With this accurate and efficient algorithm for the generation of complex. 3D shapes, a real-time NURBS interpolator was developed using a PC and the simultaneous 3D machining is accomplished.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.294-302
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• 2008

In this paper, we present a new image up-sampling method which registers low resolution images to the high resolution grid when Bayesian super-resolution image processing is performed. The proposed up-sampling method interpolates high-resolution pixels using high-frequency data lying in all the low resolution images, instead of up-sampling each low resolution image separately. The interpolation is based on B-spline non-uniform re-sampling, adjusted for the super-resolution image processing. The experimental results demonstrate the effects when different up-sampling methods generally used such as zero-padding or bilinear interpolation are applied to the super-resolution image reconstruction. Then, we show that the proposed hybird up-sampling method generates high-resolution images more accurately than conventional methods with quantitative and qualitative assess measures.

• 한국가시화정보학회:학술대회논문집
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• 2006.12a
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• pp.25-35
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• 2006

We have evaluated the performances of the following six interpolation schemes used for window deformation in particle image velocimetry (PIV): the linear, quadratic, B-spline, cubic, sinc, Lagrange interpolations. Artificially generated images comprised of particles of diameter in a range $1.1{\leq}d_p\leq10.0$ pixel were investigated. Three particle diameters were selected for detailed evaluation: $d_p$=2.2, 3.3, 4.4 pixel with a constant particle concentration 0.02 $particle/pixel^2$. Two flow patterns were considered: uniform and shear flows. The mean and random errors, and the computation times of the interpolation schemes were determined and compared.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1227-1233
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• 2003

NURBS (Non Uniform Rational B-Spline) is widely used in CAD system and NC data for high speed machining. Conventional CAM system changes NURBS surface to tessellated meshes or Z-map model, and produces linear tool path. The linear tool path is not good fur precise machining and high speed machining. In this paper, an algorithm to change linear tool path to NURBS one was studied and the machining result of NURBS tool path was compared with that of linear tool path. The N-post including both a post-processing and a virtual machining software was developed. The N-Post transforms linear tool path to NURBS tool path and quickly shades a machined product on OpenGL view, while comparing a machined surface with a original CAD one. A virtulal machined model of original tool path and post-processed tool path was compared to original CAD model. The machining error and machining time of post-processed NURBS tool path were investigated.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1111-1117
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• 2003

NURBS (Non Uniform Rational B-Spline) is widely used in CAD system and NC data for high speed machining. Conventional CAM system changes NURBS surface to tessellated meshes or Z-map model, and produces linear tool path. The linear tool path is not good for precise machining and high speed machining. In this paper, an algorithm to change linear tool path to NURBS one was studied, and the machining result of NURBS tool path was compared with that of linear tool path. The N-post, post-processing and virtual machining software was developed. The N-Post post-processes linear tool path to NURBS tool path and quickly shades machined product on OpenGL view and compares a machined product with original CAD surface. A virtual machined model of original tool path and post-processed tool path was compared to original CAD model. The machining error of post-processed NURBS tool path was reduced to 43%. The original tool path and NURBS tool path was used to machine general model using same machine tool and machining condition. The machining time of post-processed NURBS tool path was reduced up to 38%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2106-2115
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• 1994

As a pre processing for an edge detection process. edge preserving smoothing algorithm is proposed. For this purpose we used the interpolation method using B-spline basis function and scaling of digital images. By approximation of continuous function from descrete data using B-spline basis function. undetermined data between two sample can be computed. so that they smooth the surfaces of objects. Some edges having mainly low frequency components are detected using down scaling of the images. Edge maps from proposed pre processed images are hardly affected by the varying space constants($\sigma$) and threshold values used in detecting zero-crossing.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.569-573
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• 2001

An approximate representation of discrete functions {f$_{i,j}\mid$｜i, j=-1, 0, 1, …, N+1}in two variables by a fuzzy system is described. We use the cubic B-splines as fuzzy sets for the input fuzzification and spike functions as the output fuzzy sets. The ordinal number of f$_{i,j}$ in the sorted list is taken to be the out put fuzzy set number in the (i, j) th entry of the fuzzy rule table. We show that the fuzzy system is an exact representation of the cubic spline function s(x, y)=$\sum_{N+1}^{{i,j}=-1}f_{i,j}B_i(x)B_j(y)$ and that the approximation error S(x, y)-f(x, y) is surprisingly O($h^2$) when f(x, y) is three times continuously differentiable. We prove that when f(x, y) is a gray scale image, then the fuzzy system is a smoothed representation of the image and the original image can be recovered exactly from its fuzzy system representation when it is a digitized image.e.