• Title/Summary/Keyword: Wiener filter

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An Impulse Noise-Robust Wiener Filter

  • Park, Soon-Young
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1992.06a
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    • pp.33-36
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    • 1992
  • In this paper we propose the impulse noise-robust Wiener filter based on a combination of Wiener and modified trimmed mean(MTM) filters. The robust Wiener filter uses the trimming operation of the MTM filter to replace the outliers with the median within the window and the new set of samples which can be considered as the random process with same mean are inputted into the following Wiener filter. We show that the robust Wiener filter is effective in frequency selective filtering of nonstationary signals while preserving signal edges with the rejection of impulse noise.

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Effective Noise Suppression in Edge Region Using Modified Wiener Filter (수정된 Wiener 필터를 사용한 에지 영역에서의 효과적인 잡음 제거)

  • Song Young-Chul
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.3
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    • pp.173-180
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    • 2003
  • The modified Wiener filtering method is proposed for effective noise suppression in edge region of images corrupted by additive white gaussian noise. Although the pixels classified as a edge region in the conventional Wiener filter have lots of noise components, the conventional Wiener filler cannot remove noise effectively due to the preserving of edges. To reduce noise well in edge region, we modify filter coefficients of the conventional Wiener filter The modified filter coefficients increase in noise suppression effect In edge region, while they preserve edges for strong edge region. From simulation $(256{\time}256$ size, 256 graylevel images) filtered images by the proposed method show much improved subjective image quality with some improved peak signal-to-noise ratio compared to those by the conventional Wiener filtering.

A MTF Compensation for Satellite Image Using L-curve-based Modified Wiener Filter (L-곡선 기반의 Modified Wiener Filter(MWF)를 이용한 위성 영상의 MTF 보상)

  • Jeon, Byung-Il;Kim, Hongrae;Chang, Young Keun
    • Korean Journal of Remote Sensing
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    • v.28 no.5
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    • pp.561-571
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    • 2012
  • The MTF(Modulation Transfer Function) is one of quality assesment factors to evaluate the performance of satellite images. Image restoration is needed for MTF compensation, but it is an ill-posed problem and doesn't have a certain solution. Lots of filters were suggested to solve this problem, such as Inverse Filter(IF), Pseudo Inverse Filter(PIF) and Wiener Filter(WF). The most commonly used filter is a WF, but it has a limitation on distinguishing signal and noise. The L-curve-based Modified Wiener Filter(MWF) is a solution technique using a Tikhonov regularization method. The L-curve is used for estimating an optimal regularization parameter. The image restoration was performed with Dubaisat-1 images for PIF, WF, and MWF. It is found that the image restored with MWF results in more improved MTF by 20.93% and 10.85% than PIF and WF, respectively.

Region Based Contrast-to-Noise Ratio Enhancement for Medical Images (의학 영상에서의 영역 기반 해상도대잡음비 향상)

  • 송영철;최두현
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.2
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    • pp.118-126
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    • 2004
  • The modified Wiener filtering method is proposed for effective noise suppression in edge region of images corrupted by additive white gaussian noise. Although the pixels classified as a edge region in the conventional Wiener filter have lots of noise components, the conventional Wiener filter cannot remove noise effectively due to the preserving of edges. To reduce noise well in edge region, we modify filter coefficients of the conventional Wiener filter. The modified filter coefficients increase in noise suppression effect in edge region, while they preserve edges for strong edge region. From simulation (256${\times}$256 size, 256 graylevel images) filtered images by the proposed method show much improved subjective image quality with higher peak signal-to-noise ratio compared to those by the conventional Wiener filtering.

Noise reduction based on directional Wiener filter using local adaptive estimation window (가변적인 국부 추정 윈도우를 이용한 방향성 Wiener filter에 의한 잡음 제거)

  • 우동헌;김유신;김재호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.6A
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    • pp.568-574
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    • 2002
  • The main issue of noise reduction of image is how to preserve edge and reduce noise. Usually, The Wiener falter is used for this purpose. But the conventional Wiener filter cannot remove noise well in both edge and smooth region due to the single size estimation window. In addition, it ignores the correlation between pixels. In this paper, we propose a new noise reduction algorithm, in which adaptive estimation window is used according to property of smooth region and edge region. In order to make edge more clear, directional Gaussian mask and directional estimation window combines to the Wiener filter according to direction of edge. From the simulation results, it can be seen that the proposed algorithm showed improves performance in both PSNR arid subjective evaluation

Hybrid Fuzzy Adaptive Wiener Filtering with Optimization for Intrusion Detection

  • Sujendran, Revathi;Arunachalam, Malathi
    • ETRI Journal
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    • v.37 no.3
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    • pp.502-511
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    • 2015
  • Intrusion detection plays a key role in detecting attacks over networks, and due to the increasing usage of Internet services, several security threats arise. Though an intrusion detection system (IDS) detects attacks efficiently, it also generates a large number of false alerts, which makes it difficult for a system administrator to identify attacks. This paper proposes automatic fuzzy rule generation combined with a Wiener filter to identify attacks. Further, to optimize the results, simplified swarm optimization is used. After training a large dataset, various fuzzy rules are generated automatically for testing, and a Wiener filter is used to filter out attacks that act as noisy data, which improves the accuracy of the detection. By combining automatic fuzzy rule generation with a Wiener filter, an IDS can handle intrusion detection more efficiently. Experimental results, which are based on collected live network data, are discussed and show that the proposed method provides a competitively high detection rate and a reduced false alarm rate in comparison with other existing machine learning techniques.

A Novel Equivalent Wiener-Hopf Equation with TDL coefficient in Lattice Structure

  • Cho, Ju-Phil;Ahn, Bong-Man;Hwang, Jee-Won
    • Journal of information and communication convergence engineering
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    • v.9 no.5
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    • pp.500-504
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    • 2011
  • In this paper, we propose an equivalent Wiener-Hopf equation. The proposed algorithm can obtain the weight vector of a TDL(tapped-delay-line) filter and the error simultaneously if the inputs are orthogonal to each other. The equivalent Wiener-Hopf equation was analyzed theoretically based on the MMSE(minimum mean square error) method. The results present that the proposed algorithm is equivalent to original Wiener-Hopf equation. The new algorithm was applied into the identification of an unknown system for evaluating the performance of the proposed method. We compared the Wiener-Hopf solution with the equivalent Wiener-Hopf solution. The simulation results were similar to those obtained in the theoretical analysis. In conclusion, our method can find the coefficient of the TDL (tapped-delay-line) filter where a lattice filter is used, and also when the process of Gram-Schmidt orthogonalization is used. Furthermore, a new cost function is suggested which may facilitate research in the adaptive signal processing area.

Adaptive DCT-Wiener Filter for Image Restoration (영상 복원을 위한 적응 DCT-Wiener 필터)

  • 김남철;김기육
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.6
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    • pp.1005-1012
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    • 1987
  • An adaptive scalar DCT-Wiener filtering method that can be applied to the problem of restoring an image degraded by white Gaussian noise is presented. In this method, the power spectrum needed to Winer filering is adaptively estimated in block-wise according to the lical properties in transform domain. In addition, overlapping method for reducing the block artifact is considered. Experimental results show that the adaptive Wiener filter by the proposed method yields performance improvement and better image quality over the nonadaptive one and the spatial Lee filter.

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A Restoration of Degraded Medicine Images Based on Optimized Parametric Wiener Filter (최적화된 매개변수 위너필터를 이용한 훼손된 의료영상의 복원)

  • Shin, Choong-Ho;Jung, Chai-Yeoung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.5
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    • pp.1055-1063
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    • 2012
  • The noise of image is added by many environmental factors. Therefore, we need to remove these noises using the conventional filtering methods, which are optimized based on the statistical characteristic of noise. In direct restoration method, there is an inverse filter and the wiener filter. Here, the wiener filter is the optimized filter in the view of least square method. First, we are going to study the inverse filter, wiener filter, constraint least square filter. Second, in order to control the quantity, we use the parameters instead of the power spectrum ratio. But, these parameters have the conflicting condition, therefore, we optimized the variables using parametric wiener filter which adjust the application appropriately. In the simulation results, the contrast of the degraded image was enhanced and the noise was removed. Comparative experimentation was demonstrated edge preserving and noise removing property.

Wiener-Hopf Equation with Robustness to Application System (응용시스템에 강건한 Wiener-Hopf 방정식)

  • Cho, Ju-Phil;Lee, Il-Kyu;Cha, Jae-Sang
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.4
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    • pp.245-249
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    • 2011
  • In this paper, we propose an equivalent Wiener-Hopf equation. The proposed algorithm can obtain the weight vector of a TDL(tapped-delay-line) filter and the error simultaneously if the inputs are orthogonal to each other. The equivalent Wiener-Hopf equation was analyzed theoretically based on the MMSE(minimum mean square error) method. The results present that the proposed algorithm is equivalent to original Wiener-Hopf equation. In conclusion, our method can find the coefficient of the TDL (tapped-delay-line) filter where a lattice filter is used, and also when the process of Gram-Schmidt orthogonalization is used. Furthermore, a new cost function is suggested which may facilitate research in the adaptive signal processing area.