• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.873-882
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• 2011

In this paper, we propose an efficient deinterlacing algorithm which interpolates the missing scan lines by weighted summing of the intra and the inter interpolation pixels according to the spatio-temporal variation. In the spatial interpolation, we adopt a new edge based spatial interpolation method which includes edge directional refinement. The conventional edge dependent interpolation algorithms are very sensitive to noise due to the failure of estimating edge direction. In order to exactly detect edge direction, our method first finds the edge directions around the pixel to be interpolated and then refines edge direction of the pixel using weighted maximun frequent filter. Futhermore, we improve the accuracy of motion detection by reducing the possibility of motion detection error using 3 tab median filter. In the final interpolation step, we adopt weighted sum of intra and inter interpolation pixels according to spatio-temporal variation ratio, thereby improving the quality in slow moving area. Simulation results show the efficacy of the proposed method with significant improvement over the previous methods in terms of the objective PSNR quality as well as the subjective image quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4C
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• pp.217-225
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• 2011

In this paper, we propose an adaptive de-interlacing algorithm that is based on the degree of local complexity. The conventional intra field de-interlacing algorithms show the different performance according to the ways which find the edge direction. Furthermore, FDD (Fine Directional De-interlacing) algorithm has the better performance than other algorithms but the computational complexity of FDD algorithm is too high. In order to alleviate these problems, the proposed algorithm selects the most efficient de-interacing algorithm among LA (Line Average), MELA (Modified Edge-based Line Average), and LCID (Low-Complexity Interpolation Method for De-interlacing) algorithms which have low complexity and good performance. The proposed algorithm is trained by the DoLC (Degree of Local Complexity) for selection of the algorithms mentioned above. Simulation results show that the proposed algorithm not only has the low complexity but also performs better objective and subjective image quality performances compared with the conventional intra-field methods.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.265-272
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• 2015

A new technology on video frame rate up-conversion (FRUC) is presented by combining the median filter and motion estimation (ME) with an occlusion detection (OD) method. First, ME is performed to have a motion vector. Then, the OD method is used to refine motion vector in the occlusion region. Since the wrong motion vector can be obtained with high possibility in the occluded area, a median filtering that less depends on the motion vector is applied to that area, and since the motion vector is continuous and robust in the non-occluded area, BDMC(Bi-Directional Motion Compensated interpolation) is applied to obtain interpolated image in that area. BDMC using the bi-directional motion vectors achieves good results when continuity and robustness of the motion vector is higher. Experimental results show that the proposed algorithm provides better performance than the conventional approach. The average gain of PSNR (Peak Signal to Noise Ratio) is approximately 0.16 dB in the test sequences compared with BDMC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.257-266
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• 2007

In many multimedia applications, image compression is required to substantially reduce the amount of image data. This compression, however, sometimes brings artifacts. Typical artifacts are blocking artifacts and mosquito noise in DCT-coded images, and ringing artifacts around edges in wavelet-coded images. We propose a new directional postprocessing algorithm, which includes detection of the edge direction, interpolation scheme, and directional nonlinear filtering, to enhance the quality of decoded images. Simulation results show that the proposed algorithm is as effective as or more effective than other nonlinear filtering techniques.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.541-550
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• 2012

An improved method of moments using a hybrid Galerkin-interpolation technique for numerical analysis of electromagnetic wave scattering in the 3-dimensional space is presented in this paper. Basically, the EFIE(electric field integral equation) and RWG(Rao-Wilton-Glisson) basis function are used to compute a property of electromagnetic wave scattering. We propose a hybrid technique combining the existing Galerkin's method with the interpolation method to improve the efficiency of the numerical computation. Then, an index of relative distance of each cells was defined to distinguish the relatively far elements, which interpolation method can be applied. To verify the performance of the proposed technique, the analytical Mie-series solution was used to compute the theoretical RCS of a conducting sphere for the purpose of comparison. We also applied this hybrid technique to various scatterers such as trihedral/omni-directional corner-reflectors to analyze the radar backscattering properties.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.205-215
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• 2013

In digital imaging system, Bayer pattern is widely used and the observed image is degraded by optical blur during image acquisition process. Generally, demosaicing and deblurring process are separately performed in order to convert a blurred Bayer image to a high resolution color image. However, the demosaicing process often generates visible artifacts such as zipper effect and Moire artifacts when performing interpolation across edge direction in Bayer pattern image. These artifacts are emphasized by the deblurring process. In order to solve this problem, this paper proposes a deblurring algorithm combined with edge directional color demosaicing method. The proposed method is consisted of interpolation step and region classification step. Interpolation and deblurring are simultaneously performed according to horizontal and vertical directions, respectively during the interpolation step. In the region classification step, characteristics of local regions are determined at each pixel position and the directionally obtained values are region adaptively fused. Also, the proposed method uses blur model based on wave optics and deblurring filter is calculated by using estimated characteristics of local regions. The simulation results show that the proposed deblurring algorithm prevents the boosting of artifacts and outperforms conventional approaches in both objective and subjective terms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5C
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• pp.487-495
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• 2007

When error occurs during the network transmission of the image, the quality of the restored image is very serious. Therefore to maintain the received image quality, the error concealment technique is necessary. This paper presents an efficient spatial error concealment method using adaptive edge-oriented interpolation. It deals with errors on slice level. The proposed method uses boundary matching method having 2-step processes. We divide error block into external and internal region, adaptively restore each region. Because this method use overall as well as local edge characteristics, it preserves edge continuity and texture feature. The proposed technique reduces the complexity and provide better reconstruction quality for damaged images than the previous methods.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.873-876
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• 2000

본 논문에서는 양방향 움직임 보상에 의한 필드 보간(bi-directional motion-compensated field interpolation) 방법을 사용한 효과적인 디인터레이싱(de-interlacing) 기법을 제안한다. 움직임 추정(motion estimation)을 이용한 일반적인 디인터레이싱 기법은 서로 다른 샘플링 격자(sampling grid) 관계인 연속한 두 필드(field)들간의 움직임 추정을 위해 line average 같은 비교적 간단한 형태의 디인터레이싱 기법이 선행된다. 그러나, 제안한 방법은 보간할 필드(the interpolated field)의 전후 필드들의 같은 샘플링 관계인 존재하는 스캔 라인(the existing scan line)들 사이에서만 움직임 추정이 이루어지므로 구현이 용이하다. 이때 구해진 움직임 벡터는 양방향 움직임 추정을 위한 초기 값으로 사용되어 진다. 제안한 알고리듬은 기존의 움직임 정보를 이용한 기법에 비해 구현이 용이하며, 카메라 움직임이 있는 panning, zooming 영상에 특히 효율적이다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.329-330
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• 2006

This paper presents a recovery technique for images with block-based corruption by transmission losses. Conventional methods that do not consider edge directions can cause blocked blurring artifacts. In this paper, we present a block recovery scheme using Haar wavelet features. The adaptive selection of neighboring blocks is performed based on the energy ratio f wavelet subbands. The lost blocks are recovered by linear interpolation in the spatial domain using selected block pairs. The proposed directional recovery method is effective for the strong edge because it exploits the varying neighboring blocks adaptively according to the edges and the directional information in the image. The proposed method outperforms the previous methods that used only a predefined set of neighboring blocks.

• Steel and Composite Structures
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• v.48 no.5
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• pp.583-597
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• 2023

This paper introduces a novel approach to multi-material topology optimization (MTO) targeting in-plane bi-directional functionally graded (IBFG) non-uniform thickness Reissner-Mindlin plates, employing an alternative active phase approach. The mathematical formulation integrates a first shear deformation theory (FSDT) to address compliance minimization as the objective function. Through an alternating active-phase algorithm in conjunction with the block Gauss-Seidel method, the study transforms a multi-phase topology optimization challenge with multi-volume fraction constraints into multiple binary phase sub-problems, each with a single volume fraction constraint. The investigation focuses on IBFG materials that incorporate adequate local bulk and shear moduli to enhance the precision of material interactions. Furthermore, the well-established mixed interpolation of tensorial components 4-node elements (MITC4) is harnessed to tackle shear-locking issues inherent in thin plate models. The study meticulously presents detailed mathematical formulations for IBFG plates in the MTO framework, underscored by numerous numerical examples demonstrating the method's efficiency and reliability.