• 한국자동차공학회논문집
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• 제6권4호
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• pp.141-150
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• 1998

The measurement of strains in stamped sheet metal is essential to the design and manufacture of sound sheet metal products. The measured strains can also be used in verifying the reliability of the computer analysis such as finite element analysis. In most engineering applications, strains are measured from the deformed square grids or deformed circular grids in comparison with the initial undeformed grids. In such a case, however, strains are averaged in each grid and the localized strain in a region smaller than a grid size can not be measured. In the present study, the B-spline surface interpolation technique is introduced in order to measure the strains more exactly and effectively. The strains calculated by using the surface interpolation technique are compared with the strains calculated from the three-noded grids as well as with the finite element analysis.

• 한국전자파학회논문지
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• 제23권4호
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• pp.541-550
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• 2012

본 논문에서는 3차원 공간의 전자파 수치 해석을 위한 모멘트법(method of moments)의 개선된 해석 기법을 선보인다. 전자파 산란 특성을 해석하기 위해 기본적으로 EFIE(Electric Field Integral Equation)와 RWG(Rao-Wilton-Glisson) 기저 함수를 이용하였으며, 계산 효율을 높이기 위해 기존의 갤러킨(Galerkin) 기법과 중심점 보간(interpolation)법을 혼용하여 해석 시간을 단축시켰다. 이때, 계산 정확도 유지를 위해 임피던스 행렬의 각 원소간 거리를 상대 거리 지수로 정의하여 보간법 적용이 가능한 먼 거리 원소를 구분하였다. 제안된 해석 기법의 성능 검증은 금속구의 Mie-series 해법을 이용한 이론적 RCS(Radar Cross Section)를 비교/분석하였다. 또한, 본 연구 결과를 삼면-/전방향- 전파반사기와 같은 산란체에 적용하여 레이더 후방 산란 특성을 분석하였다.

• 대한음성학회지:말소리
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• 제56호
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• pp.207-223
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• 2005

The goal of language model adaptation is to improve the background language model with a relatively small adaptation corpus. This study presents a language model adaptation technique where additional text data for the adaptation do not exist. We propose the information retrieval (IR) technique with N-gram language modeling to collect the adaptation corpus from baseline text data. We also propose to use a dynamic language model interpolation coefficient to combine the background language model and the adapted language model. The interpolation coefficient is estimated from the word hypotheses obtained by segmenting the input speech data reserved for held-out validation data. This allows the final adapted model to improve the performance of the background model consistently The proposed approach reduces the word error rate by $13.6\%$ relative to baseline 4-gram for two-hour broadcast news speech recognition.

• ETRI Journal
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• 제32권3호
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• pp.390-394
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• 2010

In this paper, we propose a new super-resolution technique based on interpolation of the high-frequency subband images obtained by discrete wavelet transform (DWT) and the input image. The proposed technique uses DWT to decompose an image into different subband images. Then the high-frequency subband images and the input low-resolution image have been interpolated, followed by combining all these images to generate a new super-resolved image by using inverse DWT. The proposed technique has been tested on Lena, Elaine, Pepper, and Baboon. The quantitative peak signal-to-noise ratio (PSNR) and visual results show the superiority of the proposed technique over the conventional and state-of-art image resolution enhancement techniques. For Lena's image, the PSNR is 7.93 dB higher than the bicubic interpolation.

• 한국통신학회논문지
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• 제25권3A호
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• pp.317-324
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• 2000

강우감쇠 보상용 적응형 전송 방식을 개발하기 위하여 요구되는 가장 중요한 요소 기술 중의 하나가 강우감쇠의 동적 특성에 대한 모델링 기술인데, 본 논문에서는 이러한 강우감쇠의 동적 특성을 나타내는 데이터를 임의의 시간 간격으로 샘플링하기 위하여 시용되는 인터폴레이션 기법에 대하여 기술한다. 강우감쇠가 프랙탈 (Fractal) 프로세스라는 점을 이용하여 감쇠와 신틸레이션의 관계를 분석하고 국내 강우감쇠 데이터에 가장 적절한 파라미터를 도출하여 실제 상황에 가장 근접한 동적 강우감쇠 데이터를 생성할 수 있는 모델링 기술을 제시한다. 1분 간격으 로 측정된 강우감쇠 데이터를 이용하여 이에 대한 인터폴레이션 결과를 제시히여 강우 감쇠를 보상하기 위한 적응형 강우감쇠 기법등에 대한 보다 정확한 성능 분석이 가능함을 보였다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (2)
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• pp.952-954
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• 2005

The objective of this paper is to propose the image interpolation method with pseudomedian filter for Field warping and morphing, and to evaluate and analyze its subjective image quality. The Field warping relatively gives rise to more computing overhead, but it can use the control line to control the warping result with more elaboration. Due to the working characteristics of the image warping and morphing process, various complex geometrical transformations occur and a image interpolation technique is needed to effectively process them. Of the various interpolation techniques, bilinear interpolation which shows above average performance is the most widely used. However, this technology has its limits in the reconstructivity of diagonal edges. The proposed interpolation method is to efficiently combine the bilinear interpolation and the pseudomedian filter0based interpolation which shows good performance in the reconstructivity of diagonal edges. According to the proposed interpolation method, we could get more natural warping and morphing results than other interpolation methods.

• 컴퓨터교육학회논문지
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• 제11권5호
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• pp.57-66
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• 2008

본 논문에서는 낮은 해상도의 영상을 높은 해상도의 영상으로 보간하는 과정에서 각각의 픽셀에 대해 최적화된 매개변수를 적용하는 새로운 적응적 3차 회선 보간 기법을 제안한다. 기존의 3차 회선 보간 기법은 보간하려는 영상에 대해 동일한 매개변수를 적용하여 각 픽셀의 고유한 특성을 적응적으로 반영하지 못하였지만, 제안한 보간 기법은 픽셀의 정보에 따라 매개변수를 최적화하여 반영함으로써 주어진 영상을 고화질 영상으로 보간한다. 여러 가지 영상을 통해 본 논문에서 제안한 보간 기법과 기존에 알려진 보간 기법들을 비교하는 실험을 하였고, 도출된 실험 결과를 객관적인 지표로 제시하여 우수함을 입증하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.163-168
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• 1998

Extracting a Digital Elevation Model (DEM) from spaceborne imagery is important for cartographic applications of remote sensing data. The procedure for such DEM generation can be divided into stereo matching, sensor modelling and DEM interpolation. Among these, DEM interpolation contributes significantly to the completeness and accuracy of a DEM and, yet, this technique is often considered "trivial". However, na\ulcornere DEM interpolation may result in a less accurate and sometimes meaningless DEM. This paper reports the performance analysis of various DEM interpolation techniques. Using a manually derived DEM as reference, a number of sample points were created randomly. Different interpolation techniques were applied to the sample points to generate DEMs. The performance of interpolation was assessed by the accuracy of such DEMs. The results showed that kriging gave the best results at all times whereas nearest neighborhood interpolation provided a fast solution with moderate accuracy when sample points were large enough.

• 디지털산업정보학회논문지
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• 제16권3호
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• pp.49-58
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• 2020

Image interpolation, a technology that converts low resolution images into high resolution images, has been widely used in various image processing fields such as CCTV, web-cam, and medical imaging. This technique is based on the fact that the statistical distributions of the white Gaussian noise and the difference between the interpolated image and the original image is similar to each other. The proposed algorithm is composed of three steps. In first, the interpolated image is derived by random image interpolation. In second, we derive weighting functions that are used to apply non-local mean filtering. In the final step, the prediction error is corrected by performing non-local mean filtering by applying the selected weighting function. It can be considered as a post-processing algorithm to further reduce the prediction error after applying an arbitrary image interpolation algorithm. Simulation results show that the proposed method yields reasonable performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.581-584
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• 1998

To obtain 3-D topography of EEG records, we propose a new method based on the polygon mapping technique. The method has the low complexity to calculate the interpolation of the EEG records on the scalp and maintains the high resolution topography because the polygon technique performs the interpolation at the only vertexes of each polygon. We implemented the topographic system with 3D barycentric, 3D polynomial and spherical spline algorithms in a personal computer.