Airplane Noise Removal Demonstration: Difference between revisions
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soundsc(e(1,6000:end),Fs); |
soundsc(e(1,6000:end),Fs); |
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%playaudio(e); (For Linux without octave-forge.) |
%playaudio(e); (For Linux without octave-forge.) |
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The record.m function in Ubuntu Maverick is broken. You can use this one instead. |
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## Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2003, 2004, 2005, |
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## 2006, 2007 John W. Eaton |
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## |
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## This file is part of Octave. |
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## |
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## Octave is free software; you can redistribute it and/or modify it |
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## under the terms of the GNU General Public License as published by |
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## the Free Software Foundation; either version 3 of the License, or (at |
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## your option) any later version. |
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## |
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## Octave is distributed in the hope that it will be useful, but |
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## WITHOUT ANY WARRANTY; without even the implied warranty of |
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## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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## General Public License for more details. |
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## |
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## You should have received a copy of the GNU General Public License |
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## along with Octave; see the file COPYING. If not, see |
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## <http://www.gnu.org/licenses/>. |
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## -*- texinfo -*- |
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## @deftypefn {Function File} {} record (@var{sec}, @var{sampling_rate}) |
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## Records @var{sec} seconds of audio input into the vector @var{x}. The |
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## default value for @var{sampling_rate} is 8000 samples per second, or |
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## 8kHz. The program waits until the user types @key{RET} and then |
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## immediately starts to record. |
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## @seealso{lin2mu, mu2lin, loadaudio, saveaudio, playaudio, setaudio} |
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## @end deftypefn |
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## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at> |
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## Created: 19 September 1994 |
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## Adapted-By: jwe |
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## And adapted again 11/25/2010 by Rob Frohne |
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function X = record (sec, sampling_rate) |
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if (nargin == 1) |
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sampling_rate = 8000; |
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elseif (nargin != 2) |
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print_usage (); |
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endif |
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file = tmpnam (); |
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file= [file,".wav"]; |
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input ("Please hit ENTER and speak afterwards!\n", 1); |
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cmd = sprintf ("rec -c1 -r%d %s trim 0 %d", |
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sampling_rate, file, sec) |
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system (cmd); |
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X = wavread(file); |
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endfunction |
Revision as of 11:45, 30 November 2010
% Demonstration of LMS algorithm for noise cancellation. % Rich Kozick, Spring 1997 % Rob Frohne's modifications for Aircraft Noise Cancellation. % modifications for Macintosh 2000. (commented out here) % Rob Frohne's modifications for Linux. % Aircraft noise cancellation simulation. % Desired signal clear all Totaltime=3; system("aoss espeak 'Hit a key and speak the signal.'"); Fs=8000; %sample rate. st=record(Totaltime,Fs); s = st'; Ls = length(s); % Interference + random noise system("aoss espeak 'Hit a key and make the noise!'"); %pause(); nt = record(Totaltime, Fs); n = nt'; %Sign = 0.01; %Dn=20; % Delay of the noise that appears in y. %n = n(1:Ls) + Sign*randn(Ls,1); %an = [0 .01 -.5 1 -.5 .1 .01 0]; %bn = 4*[0 0 0 0 0 0 0 0 0 0 0 0 0 0 .5 1 .5]; bn=rand(1,20); an = [1]; %sys = tf(an,bn,1/Fs); %bode(sys); %figure(1); nf = filter(bn,an,n); %nf = [nf(Dn:(Ls)); zeros(Dn-1,1)] + Sign*randn(Ls,1); y = s + nf; %Sigx = 0.01; %ax = [1]; % bx and ax are filtering on n to produce x %bx = [0 0 0 .1 1 .1]; %Dx = 1; % Delay of n that appears in x %x = filter(bx, ax, n);%x = [x(Dx:(Ls)); zeros(Dx-1,1)] + Sigx*randn(Ls,1); %x = x + Sigx*randn(1,Ls); system("aoss espeak 'Here is the noisy signal.'"); soundsc(y,Fs); N = 20; % Length of adaptive filter % LMS algorithm for adaptive noise cancellation h = zeros(N,1); %mu = 1/(10*N*var(n)); mu = .05; for k=N:Ls xk = n(k:-1:(k-N+1)); nhat(k) = h'*xk'; e(k) = - y(k) + nhat(k); h = h - mu*e(k)*xk'/(xk*xk'); % For the previous line. end % The signal estimate is in the vector e %speak('Here is the cleaned signal.'); system("aoss espeak 'Here is the cleaned signal.'"); soundsc(e(1,6000:end),Fs); %playaudio(e); (For Linux without octave-forge.)
The record.m function in Ubuntu Maverick is broken. You can use this one instead.
## Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2003, 2004, 2005, ## 2006, 2007 John W. Eaton ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or (at ## your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {} record (@var{sec}, @var{sampling_rate}) ## Records @var{sec} seconds of audio input into the vector @var{x}. The ## default value for @var{sampling_rate} is 8000 samples per second, or ## 8kHz. The program waits until the user types @key{RET} and then ## immediately starts to record. ## @seealso{lin2mu, mu2lin, loadaudio, saveaudio, playaudio, setaudio} ## @end deftypefn
## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at> ## Created: 19 September 1994 ## Adapted-By: jwe ## And adapted again 11/25/2010 by Rob Frohne function X = record (sec, sampling_rate) if (nargin == 1) sampling_rate = 8000; elseif (nargin != 2) print_usage (); endif file = tmpnam (); file= [file,".wav"]; input ("Please hit ENTER and speak afterwards!\n", 1); cmd = sprintf ("rec -c1 -r%d %s trim 0 %d", sampling_rate, file, sec) system (cmd); X = wavread(file); endfunction