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Spectral design of weighted median filters admitting negative weights

I. Shmulevich, G.R. Arce
2001 IEEE Signal Processing Letters  
Index Terms-Impulsive noise, sample selection probability, spectral response, weighted median filter.  ...  A closed-form spectral optimization method for the design of weighted median (WM) filters admitting negative weights is presented.  ...  While the latter can be designed by a variety of well-known methods for frequency selective applications, the resulting weighted median filters possess similar frequency selective behavior.  ... 
doi:10.1109/97.975879 fatcat:zxfgb3r6l5bnbn4viuye3h7cvm

A general weighted median filter structure admitting negative weights

G.R. Arce
1998 IEEE Transactions on Signal Processing  
In fact, weighted median smoothers are analogous to normalized FIR linear filters constrained to have only positive weights.  ...  Although weighted median smoothers offer advantages over traditional linear finite impulse response (FIR) filters, it is shown in this paper that they lack the flexibility to adequately address a number  ...  (b) Linear FIR filter output. (c) Weighted median smoother output. (d) Weighted median filter output with real-valued weights. Fig. 4 . 4 Frequency selective filter outputs in noise.  ... 
doi:10.1109/78.735296 fatcat:zkmn6pyvvvfhdhce2igrsjgime

Weighted Iterative Truncated Mean Filter

Zhenwei Miao, Xudong Jiang
2013 IEEE Transactions on Signal Processing  
Index Terms-ITM filter, weighted median filter, noise suppression, nonlinear filter, band-pass filter, high-pass filter.  ...  In this paper, a rich class of filters named weighted ITM (WITM) filters are proposed. By iteratively truncating the extreme samples, the output of the WITM filter converges to the weighted median.  ...  Frequency Selective WITM Filters A quadratic swept-frequency chirp signal spanning instantaneous angular frequency ranging from 0 to is used to test the WITM filters in frequency selection.  ... 
doi:10.1109/tsp.2013.2267739 fatcat:qczragxqbzgy3ft25syfa24ume

Resonance Image Enhancement using Hybrid Center Weighted Median Filter and Bacteria Foraging Optimization

2020 International journal of recent technology and engineering  
HCWM Filter is the hybrid filter derived by combining the Center Weighted Median Filter and the Weiner Filter.  ...  This paper recommends an unique method for the brain MR image enhancement, that is centred on the Hybrid Center Weighted Median (HCWM) filter and Bacteria Foraging Optimization (BFO).  ...  The proposed system shows the application of the hybrid center weighted median filter on MR brain images for removing high frequency components and to enhance it.  ... 
doi:10.35940/ijrte.e6378.018520 fatcat:ps3iuxzjy5gofkfam7cvcbut7a

Pre-Processing and Image Enhancement Techniques

Sivaramakrishnan A., M. Vinoth Kumar
2020 IJARCCE  
The proposed mammogram image enhancement method, the film artifacts such as labels and X-ray marks are removed and the high frequency components are removed using various filtering.  ...  This article deals with pre-processing and enhancement activities such as removal of film artifacts and labels, filtering the image.  ...  Weighted Median Filter The Weighted Median Filter is to remove high frequency component noise from MRI Image without disturbing the edges.  ... 
doi:10.17148/ijarcce.2020.9717 fatcat:cxgfciic4jhlxlzfcozth3eo2y

Design of linear combination of weighted medians

Kang-Sun Choi, A.W. Morales, Sung-Jea Ko
2001 IEEE Transactions on Signal Processing  
This paper introduces a novel nonlinear filtering structure: the linear combination of weighted medians (LCWM).  ...  Based on this observation, we introduce a class of LCWM filters whose output is given by a linear combination of weighted medians of the input sequence.  ...  ANALOGY BETWEEN WEIGHTED MEDIAN FILTERS AND FIR FILTERS A.  ... 
doi:10.1109/78.942623 fatcat:rkxzygb74ramniqjeb7ncinofy

Edge-preserving texture filtering for real-time rendering

Yuan-Chung Lee, Chein-Wei Jen
2003 The Visual Computer  
Texture filtering is essential in enhancing the visual quality of real-time rendering.  ...  This paper proposes a novel texture-filtering algorithm, which consists of edge-preserving interpolation and edgepreserving MIP-map prefiltering.  ...  The simple low-pass filter first extracts the low-frequency signals from the source texels. These signals are subsequently interpolated by the weighted selection directional interpolation module.  ... 
doi:10.1007/s00371-002-0169-8 fatcat:x44sk4hnqrfq7jdahuivcl2mbi

MR Image Enhancement using Adaptive Weighted Mean Filtering and Homomorphic Filtering

P. Yugander, C.H. Tejaswini, J. Meenakshi, K. Samapath kumar, B.V.N. Suresh Varma, M. Jagannath
2020 Procedia Computer Science  
In this paper, the noisy magnetic resonance (MR) brain images were enhanced using Adaptive Weighted Mean Filtering (AWMF) and homomorphic filtering. The MR images always suffer from low contrast.  ...  Then de-noised image is enhanced using homomorphic filter. The efficiency of the proposed method is compared with median filter (MF) and based on pixel density filter (BPDF).  ...  For example, adaptive median filtering [8] , fast switching based median-mean filter [9] , an adaptive weighted median filter [10] , and adaptive weighted mean filter.  ... 
doi:10.1016/j.procs.2020.03.334 fatcat:s35odwynsze7jg44g2enhdbsp4

A Novel Weighted Median Switching Filter for Denoising Corrupted Images

Saurabh Agrawal, J. S. Yadav, Ravindranath C. C
2013 International Journal of Computer Applications  
This paper presents a new weighted switching median filter is proposed to restore images corrupted by noise.  ...  Based on this classification the weights associated with the median filter employed for denosing is determined.  ...  But in case of Impulse and Gaussian noise pixel weighted median filter is applied. Weights associated with the median filter are altered based on the pixel in consideration.  ... 
doi:10.5120/10756-5629 fatcat:uo35pw6e3rfvtefkgxnzhjq7eq

Recursive weighted median filters admitting negative weights and their optimization

G.R. Arce, J.L. Paredes
2000 IEEE Transactions on Signal Processing  
A recursive weighted median (RWM) filter structure admitting negative weights is introduced.  ...  Index Terms-Adaptive filter, median filters, nonlinear signal processing, recursive median filter, robustness.  ...  In this paper, we denote these structures as "smoothers" to differentiate them from the more powerful WM filter structures that admit negative weights that can synthesize general frequency selecting filtering  ... 
doi:10.1109/78.824671 fatcat:tm3spjsf5rhg7ilt3fatsf53qy

Non-Local Means Image De-noising Based on Wavelet Transform

2016 Revista Técnica de la Facultad de Ingeniería Universidad del Zulia  
As wavelet analysis has excellent localization property and multi-resolution analysis in time domain and frequency domain, this paper proposes a non-local means filtering based on discrete wavelet transform  ...  (DWT-NLM) by combining non-local means on the basis of wavelet theory to analyze the noise distribution in the low frequency and high frequency of wavelet.  ...  IMAGE DE-NOISING Median Filter As a non-linear filter, median filter uses the median of template neighborhood to replace the pixel gray value of the template center.  ... 
doi:10.21311/ fatcat:72hiem2tnngvxorw2uvnf6krjm

An Improved Image Filtering Algorithm for Mixed Noise

Chun He, Ke Guo, Huayue Chen
2021 Applied Sciences  
Sparse Coding (TWSC), Block Matching and 3D Filtering (BM3D), and Weighted Nuclear Norm Minimization (WNNM).  ...  Specifically, we adjusted the size of window of the median filtering algorithm and improved the method of detecting noise points.  ...  Compared with the Adaptive Median Filtering (AMF) algorithm, the weighted multilevel median filtering algorithm, and the multilevel nonlinear weighted mean median filtering algorithm, the improved algorithm  ... 
doi:10.3390/app112110358 fatcat:np4ubq6ovzcafdmax57acuxugm

Helicopter rotor blade frequency evolution with damage growth and signal processing

Niranjan Roy, Ranjan Ganguli
2005 Journal of Sound and Vibration  
Finally, since operational data are noisy and also contaminated with outliers, denoising algorithms based on recursive median filters and radial basis function neural networks and wavelets are studied  ...  A novel recursive median filter is designed using integer programming through genetic algorithm and is found to have comparable performance to neural networks with much less complexity and is better than  ...  Filter weight selection We consider the 3rd lag mode frequency as our test signal, and use a nine-point weighted symmetric recursive median filter for our study.  ... 
doi:10.1016/j.jsv.2004.05.015 fatcat:tuo52olfxneirjv2xq2cppslri

A Review on Removal of Salt And Pepper Noise From Digital Images

2016 International Journal Of Engineering And Computer Science  
In frequency domain the filtering action is done by mapping the spatial domain into the frequency domain by taking fourier transform of the image function.  ...  By mapping the image into frequency domain an image can provide an insight for filtering operations.  ...  Frequency domain filters such as high pass filters help in preserving the image details such as edges. The work done is only on gray scale images. It can be extended to coloured images.  ... 
doi:10.18535/ijecs/v5i9.56 fatcat:k5beis3fmbc7nelesqnga7vmmi

Weighted D-filtering

W.-R. Wu, A. Kundu
1991 IEEE Transactions on Circuits and Systems  
The new filter computes its output as the median of weighted averages, instead of plain averages as used in the Hodges-Lehman D-filter, of symmetrically placed order statistics.  ...  A number of other filters such as multilevel median filter [ l ] , [8], FIR hybrid median filter [ l ] , etc., are proposed to preserve TLD of the image.  ...  For the m X m window, all the pixels on these four diagonals are selected for filtering. Thus the window selection is similar to that of the multilevel median filter [81.  ... 
doi:10.1109/31.75402 fatcat:d3wlsotfwrhedovcbdxsyvfz5e
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