## Source code for Wiener Filter

Started by in comp.dsp19 years ago 4 replies

I need to do a quick test on standard Wiener Filter for speech enhancement, to see how is the result of noise reduction, some paper say it may...

I need to do a quick test on standard Wiener Filter for speech enhancement, to see how is the result of noise reduction, some paper say it may contain music tones. I probaly will do some modification it base on it. The structure of Wiener Filter is simply as s(n) -> FFT -> Wiener Filter -> IFFT -> S(n) I think Wiener filter is popularly used for one channel noise suppressio

## Why Wiener?

Started by in comp.dsp16 years ago 3 replies

Linear estimation theory is normally credited to Wiener around 1949 though he did have a classified report in the war years. Also, Kolmogorov...

Linear estimation theory is normally credited to Wiener around 1949 though he did have a classified report in the war years. Also, Kolmogorov published the discrete-time version.... Andrei N. Kolmogorov. Interpolation and extrapolation of stationary random sequences (in Russian). Izvestiya AN SSSR. Mathematics series, 5:314, 1941 in 1941. Wiener did continuous time. So why talk of Wiener f...

## Wiener Filter Implementation Question.

Started by in comp.dsp15 years ago 3 replies

Hello all, I have implemented a WIENER FILTER in the Spectral Domain for noise reduction purposes in Matlab (for speech...

Hello all, I have implemented a WIENER FILTER in the Spectral Domain for noise reduction purposes in Matlab (for speech signals). Question: Can the Wiener Filter factors in frequency domain have values above 1 or below -1? For power spectrum densities i simply used absolute values of the FFT of the signals. The noise is white noise. I use the following to calculate the Wiener Filter:...

## IIR Wiener Filter in Matlab

Started by in comp.dsp16 years ago 1 reply

I am attempting to code an IIR wiener filter for system identification in Matlab, but I am currently having some difficulty with the theory......

I am attempting to code an IIR wiener filter for system identification in Matlab, but I am currently having some difficulty with the theory... Can someone please clarify? To find the spectral factorization, my understanding is that I take the roots of the autocorrelation sequence, then select those whose magnitude fall within the unit circle? Does anyone have any example IIR Wiener Matlab sc...

## Inquiry about white noise and wiener deconvolutions

Started by in comp.dsp14 years ago 3 replies

I?m interested in trying a wiener deconvolution for some electro-physiology data that I have recorded, and I?m not sure how to estimate the white...

I?m interested in trying a wiener deconvolution for some electro-physiology data that I have recorded, and I?m not sure how to estimate the white noise power for use in that. According to Wikipedia, the proper terms to use are the PSD of both the noise and the true signal in the equation used for the wiener deconvolution. (As an aside question, I was going to use the recorded signal as a proxy

## Symmetric Wiener Filter

Started by in comp.dsp16 years ago 3 replies

Hi all, I have an exercise, and i should compute the wiener-hopf equations for a symmetric zero phase wiener filter. I have started from the...

Hi all, I have an exercise, and i should compute the wiener-hopf equations for a symmetric zero phase wiener filter. I have started from the fact that the symmetry and the zero phase imply h[n]=h[-n] for the coefficients of the filter and I compute the following equation sum{h(l)[Rx(k-l)+Rx(l-k)+Rx(k+l)+Rx(-k-l)]}=Rxs(k)+Rxs(-k), where l=0,...,N , k=0,...,N Rx is the autocorrelation Rxs is t...

## Wiener solution for equalization

Started by in comp.dsp16 years ago 4 replies

In order to find the Wiener solution for equalization purpose, do I need to provide delay to the desired signal as in the case of LMS...

In order to find the Wiener solution for equalization purpose, do I need to provide delay to the desired signal as in the case of LMS algorithm? Will the result of the Wiener solution become better if I provide some delay to the desired signal? Thanks.

## Good Wiener filter implementation in C/C++?

Started by in comp.dsp18 years ago 6 replies

I've been looking for a modern, efficient Wiener filter implementation written in C or C++, and I can't find anything very recent (or one...

I've been looking for a modern, efficient Wiener filter implementation written in C or C++, and I can't find anything very recent (or one that actually works). I'd like one implemented on top of fftw if possible. Anyone got any pointers to one?

## Wavelet domain wiener filter matlab implementation regarding

Started by in comp.dsp11 years ago 3 replies

Dear Sir/Madam, I need to perform wavelet domain wiener filtering to denoise ecg signal as a part of my project First I performed...

Dear Sir/Madam, I need to perform wavelet domain wiener filtering to denoise ecg signal as a part of my project First I performed wiener filtering in fourier domain The code is as follows: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function output = Wienerfilt(noisy,clean) nois=clean-noisy; stdnois=std(nois); y=fft(clean); fftnsy=fft(noisy); n=length(clean)...

## Comparing matched and Wiener filters

Started by in comp.dsp14 years ago 27 replies

Hi, This is something that's been bugging me for the last couple of days. With the understanding that both are linear, we define the...

Hi, This is something that's been bugging me for the last couple of days. With the understanding that both are linear, we define the matched filter as the one that maximises the output SNR, and the Wiener filter as the one that minimises the mean square error (MSE). Superficially, these definitions sound almost identical. However, even in the simplest model (estimating a scalar value wi...

## Wiener Filter

Started by in comp.dsp2 years ago

...

https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-011-introduction-to-communication-control-and-signal-processing-spring-2010/readings/MIT6_011S10_chap11.pdf I refer to these notes. Ive been using Wiener filters for some time now but it is teh causal version. I am puzzled by the uncausal one because it is unstable. Therefore how do people manage to use it? Is

## Need Good Resource On Wiener Filter

Started by in comp.dsp17 years ago 2 replies

Hi, Does anyone have a suggestion for a book(text book preferably) that contains some good examples on auto-regressive signals? I'm...

Hi, Does anyone have a suggestion for a book(text book preferably) that contains some good examples on auto-regressive signals? I'm interested in understanding how to derive the non-causal and causal solutions of 1st order Wiener Filters. A point in the right direction would be greatly appreciated. tks, -David

## should first coef of spiking decon Wiener filter be positive?

Started by in comp.dsp6 years ago

Spiking decon has been used in geophysics for over 50 years. An FIR Wiener filter is computed by Levinson recursion. The inputs are the...

Spiking decon has been used in geophysics for over 50 years. An FIR Wiener filter is computed by Levinson recursion. The inputs are the autocorrelation of the trace, and an impulse (1,0,0,0,...) as desired signal. It is based on certain assumptions, such as the wavelet being minimum phase and stationary (which are only approximations in reality). Now I have been looking at an open-source pac...

## Multi input Weiner Filter

Started by in comp.dsp14 years ago 6 replies

For the standard SISO Wiener filter we minimize the cost J J=E[e^2]=E(d-W'X)^2 where W is a vector of weights and X is a vector of...

For the standard SISO Wiener filter we minimize the cost J J=E[e^2]=E(d-W'X)^2 where W is a vector of weights and X is a vector of regressers. (d is desired output) Also ' denotes transpose. We do this by diferentiating wrt the weight vector W and arrive at the standard Wiener solution. However, in the case where W is asymmetric Matrix and d is a vector (also X is a vector still) we...

## Doubt on wiener filter implementation.

Started by in comp.dsp16 years ago

Hi, I am currently working on a speech enhancement project. I am implementing a noise cancellation system using Wiener filter. > From what I...

Hi, I am currently working on a speech enhancement project. I am implementing a noise cancellation system using Wiener filter. > From what I read in the text books and from the net , I got the transfer function for the filter as h(f) = {psd(noisySignal) - psd(noiseSignal) } / psd(noisySignal). I implemented this in matlab ,but the result was a highly distorted signal.

## LMS vs Wiener

Started by in comp.dsp15 years ago 2 replies

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise...

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise v(n) with known variance and mean x(n) = d(n) + v(n); the goal is define an optimal Wiener filter of 101 coefficients. (I call it "toy situation" because I have at the same time the value of the noisy signal and the value of the original signal) ...

## LMS vs Wiener

Started by in comp.dsp15 years ago 1 reply

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise...

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise v(n) with known variance and mean x(n) = d(n) + v(n); the goal is define an optimal Wiener filter of 101 coefficients. (I call it "toy situation" because I have at the same time the value of the noisy signal and the value of the original signal) ...

## Wiener filtering using mean-squared method: variance problem

Started by in comp.dsp14 years ago

I am trying to implement a low pass Wiener filter using the mean- squared method, to provide elimination of noisy areas, background texture...

I am trying to implement a low pass Wiener filter using the mean- squared method, to provide elimination of noisy areas, background texture smoothing, and contrast enhancement. The algorithm I'm using is (to produce output image Q from input image P), to evaluate a 3x3 neighbourhood for each pixel, and Q(x,y) = mu + [ (sigmasquared - nusquared)/sigmasquared ] ( P (x,y) - mu ) Wher...

## Wiener adaptive filtering and windowing: discontinui

Started by in comp.dsp17 years ago 1 reply

Hi all, I wrote a simple adaptive wiener filter in matlab to remove noise from an audio file. The routine computes correlation matrixes on a...

Hi all, I wrote a simple adaptive wiener filter in matlab to remove noise from an audio file. The routine computes correlation matrixes on a rectangular window of 256 samples but I have difficulties when rebuilding the whole file: on every edge of the filtered windows I have a discontinuities, so the global result is corrupted. http://img208.imageshack.us/img208/950/wiener4kq.jpg Cou...

## Wiener filter implementation problem; Artifacts

Started by in comp.dsp15 years ago

Hi everybody, I use the below matlab implementation of a Wiener filter, but I get strange artifacts when i process the noisy audio file. Can...

Hi everybody, I use the below matlab implementation of a Wiener filter, but I get strange artifacts when i process the noisy audio file. Can somebody take a look at my code and tell me if there is something wrong, or suspicios. When I process my noisy signal with this prgramm i get strange artifacts, for example i see in the spectogram that some coefficients in the noise speech at very hi...