• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.4
• /
• pp.369-375
• /
• 2011

Design is important in the IT, digital appliance, and auto industries. Aesthetic and art images are being applied for better quality of the products. Most image patterns are complex and much lead-time is required to implement them to the product design process. A precise reverse engineering method generating 2.5D engraving models from 2D artistic images is proposed through the image processing, NURBS interpolation and 2.5D reconstruction methods. To generate 2.5D TechArt models from the art images, boundary points of the images are extracted by using the adaptive median filter and the novel MBF (modified boundary follower) algorithm. Accurate NURBS interpolation of the points generates TechArt CAD models. Performance of the developed system has been confirmed through the quick turnaround 2.5D engraving simulation linked with the commercial CAD/CAM system.

• Proceedings of the KOSOMBE Conference
• /
• v.1990 no.11
• /
• pp.38-41
• /
• 1990

A new spline function for resampling discrete signal adaptively is proposed. In general, B-spline function is used for an image interpolation because of its smoothness and continuity, but accompanies a large amount of blurring effect. Hence, we developed a new spline function to remedy this effect, with two procedures ; deblurring of Gaussian blurring and diminishing of aliasing effect caused by deblurring procedure. The proposed function has a parametric expression with $\alpha$ which is related to the variance of Gaussian blurring model. Locally adaptive resampling scheme is obtained by changing a according to statistical characteristics of an image. The proposed, interpolation function shows edge-sharpening effect as well as noise smoothing, with comparison to the conventional schemes.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.30 no.1 s.244
• /
• pp.8-15
• /
• 2006

A Sparse Point Representation(SPR) based on interpolation wavelets is presented. The SPR is implemented for the purpose of CFD data compression. Unlike conventional wavelet transformation, the SPR relieves computing workload in the similar fashion of lifting scheme that includes splitting and prediction procedures in sequence. However, SPR skips update procedure that is major part of lifting scheme. Data compression can be achieved by proper thresholding method. The advantage of the SPR method is that, by keeping even point physical values, low frequency filtering procedure is omitted and its related unphysical thresholing mechanism can be avoided in reconstruction process. Extra singular feature detection algorithm is implemented for preserving singular features such as shock and vortices. Several numerical tests show the adequacy of SPR for the CFD data. It is also shown that it can be easily extended to nonlinear adaptive wavelets for enhanced feature capturing.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2006.04a
• /
• pp.849-856
• /
• 2006

This paper is to examine the applicability of ordinary Kriging interpolation(OK) to the p-adaptivity of the finite element analysis that is based on variogram. In the p-refinement, the analytical domain has to be refined automatically to obtain an acceptable level of accuracy by increasing the p-level non-uniformly or selectively. In case of non-uniform p-distribution, the continuity between elements with different polynomial orders is achieved by assigning zero higher-order derivatives associated with the edge in common with the lower-order derivatives. It is demonstrated that the validity of the proposed approach by analyzing results for stress singularity problem.

• ETRI Journal
• /
• v.33 no.2
• /
• pp.295-298
• /
• 2011

We propose a motion-compensated frame interpolation method in which an accurate backward/forward motion vector pair (MVP) is estimated based on a parabolic motion model. A reliability measure for an MVP is also proposed to select the most reliable MVP for each interpolated block. The possibility of deformation of bidirectional corresponding blocks is estimated from the selected MVP. Then, each interpolated block is produced by combining corresponding blocks with the weights based on the possibility of deformation. Experimental results show that the proposed method improves PSNR performance by up to 2.8 dB as compared to conventional methods and achieves higher visual quality without annoying blockiness artifacts.

• Proceedings of the IEEK Conference
• /
• 2000.09a
• /
• pp.889-892
• /
• 2000

본 논문에서는 효과적인 De-interlacing을 위한 Edge based Median Filter와 3-Step AMPD(Adaptive Minimum Pixel Difference Filter)를 제안한다. Motion Adaptive De-interlacing 방법에서 중요한 요소인 Motion Hissing에 의한 에러를 방지하기 위해 입력 영상을 4 가지 유형으로 구분하여 각 영상에 따라 다른 임계 값을 적용하여 정확한 화소 값을 보간 하는AMPD(Adaptive Minimum Pixel Difference) Filter를 사용하며 Moving Diagonal Edge의 효과적인 보간을 위해서 방향 필터를 사용하여 Edge Map을 추출한 뒤 Edge에 따라 가변적인 후보 화소를 선택하는 Edge based Median Filter를 사용하여 성능을 향상시켰다. 또한 입력되는 영상을 움직임 영역, 정지 영역, 경계 영역으로 나누어 적응적으로 보간 하여 연산 효율을 높였다. 제안된 방법은 다양한 영상에 대한 모의실험을 통해 기존의 방법에 비해 뛰어난 성능 개선을 보였다.

• Journal of Mechanical Science and Technology
• /
• v.20 no.12
• /
• pp.2189-2196
• /
• 2006

The present work is concerned with the development of a procedure for adaptive computations of shear localization problems. The maximum jump of equivalent strain rates across element boundaries is proposed as a simple error indicator based on interpolation errors, and successfully implemented in the adaptive mesh refinement scheme. The time step is controlled by using a parameter related to the Lipschitz constant, and state variables in target elements for refinements are transferred by $L_2$-projection. Consistent tangent moduli with a proper updating scheme for state variables are used to improve the numerical stability in the formation of shear bands. It is observed that the present adaptive mesh refinement procedure shows an excellent performance in the simulation of shear localization problems.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1291-1296
• /
• 2003

The objective of the present research is to develop a wavelet-based multiscale adaptive Galerkin method for membrane eigenvalue analysis. Since approximate eigensolutions at a certain resolution level can be good guesses, which play an important role in typical iterative solvers, at the next resolution level, the multiresolution iterative solution approach by wavelets can improve the solutionconvergence rate substantially. The intrinsic difference checking nature of wavelets can be also utilized effectively to develop an adaptive strategy. The present wavelet-based approach will be implemented for the simplest vector iteration method, but some important aspects, such as convergence speedup, and the reduction in the number of nodes can be clearly demonstrated.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.52 no.10
• /
• pp.606-610
• /
• 2003

Noise subtraction using reference channel data has been used to improve signal-to-noise ratio in magnetoencephalography. In this paper, an adaptive noise subtraction model is proposed and parameters for the model are optimized. A criterion to determine an optimal update period for the filter coefficients is proposed based on the ratio of peak amplitude of evoked field (N100m) divided by the output standard deviation. Experiments are carried out using a 40 channel MEG system. From the experiments, the proposed noise subtraction method shows superior performances over existing non-adaptive methods. Two-dimensional topographic map is shown for a diagnosis with a cubic spline interpolation.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.48 no.6
• /
• pp.61-67
• /
• 2011

Stereoscopic 3D video can be transmitted by frame-compatible packing format to fulfill the compatibility requirement with the existing digital TV. Then, the reduced stereo image needs to be expanded to the original size at the receiver. This paper proposes an adaptive interpolation method for the discarded image lines. The horizontal line-based linear filter and NEDI6 filter are used selectively for the interpolation of each pixel. Experimental results show that the NEDI6 combined with the horizontal line-based linear filter yields better image quality than the bilinear method by around 0.6dB.