Airplane Noise Removal Demonstration - Revision history

Frohro at 19:27, 7 December 2015

2015-12-07T19:27:14Z

@@ Line 1: / Line 1: @@
-  % Demonstration of LMS algorithm for noise cancellation.
+  <nowiki>
- % Rich Kozick, Spring 1997
+% Demonstration of LMS algorithm for noise cancellation.
- % Rob Frohne's modifications for Aircraft Noise Cancellation.
+% Rich Kozick, Spring 1997
- % modifications for Macintosh 2000. (commented out here)
+% Rob Frohne's modifications for Aircraft Noise Cancellation.
- % Rob Frohne's modifications for Linux.
+% modifications for Macintosh 2000. (commented out here)
- % Aircraft noise cancellation simulation.
+% Rob Frohne's modifications for Linux.
- % Desired signal
+% Aircraft noise cancellation simulation.
- clear all
+% Desired signal
- Totaltime=3;
+clear all
- system("aoss espeak 'Hit a key and speak the signal.'");
+Totaltime=3;
- Fs=8000; %sample rate.
+system("espeak 'Hit a key and speak the signal.'");
- st=record(Totaltime,Fs);
+Fs=8000; %sample rate.
 The record.m function in Ubuntu Maverick is broken.  You can use this one instead.

Frohro at 18:46, 30 November 2010

2010-11-30T18:46:14Z

← Older revision		Revision as of 11:46, 30 November 2010
Line 91:		Line 91:
	## @seealso{lin2mu, mu2lin, loadaudio, saveaudio, playaudio, setaudio}		## @seealso{lin2mu, mu2lin, loadaudio, saveaudio, playaudio, setaudio}
	## @end deftypefn		## @end deftypefn

	## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>		## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at>
	## Created: 19 September 1994		## Created: 19 September 1994

Frohro at 18:45, 30 November 2010

2010-11-30T18:45:19Z

← Older revision		Revision as of 11:45, 30 November 2010
Line 60:		Line 60:
	soundsc(e(1,6000:end),Fs);		soundsc(e(1,6000:end),Fs);
	%playaudio(e); (For Linux without octave-forge.)		%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

Frohro at 18:39, 30 November 2010

2010-11-30T18:39:37Z

← Older revision		Revision as of 11:39, 30 November 2010
Line 4:		Line 4:
	% modifications for Macintosh 2000. (commented out here)		% modifications for Macintosh 2000. (commented out here)
	% Rob Frohne's modifications for Linux.		% Rob Frohne's modifications for Linux.

	% Aircraft noise cancellation simulation.		% Aircraft noise cancellation simulation.

	% Desired signal		% Desired signal

	clear all		clear all
	Totaltime=3;		Totaltime=3;
	system("aoss espeak 'Hit a key and speak the signal.'");		system("aoss espeak 'Hit a key and speak the signal.'");

	Fs=8000; %sample rate.		Fs=8000; %sample rate.
	st=record(Totaltime,Fs);		st=record(Totaltime,Fs);
	s = st';		s = st';
	Ls = length(s);		Ls = length(s);

	% Interference + random noise		% Interference + random noise
	system("aoss espeak 'Hit a key and make the noise!'");		system("aoss espeak 'Hit a key and make the noise!'");
Line 35:		Line 30:
	nf = filter(bn,an,n);		nf = filter(bn,an,n);
	%nf = [nf(Dn:(Ls)); zeros(Dn-1,1)] + Sign*randn(Ls,1);		%nf = [nf(Dn:(Ls)); zeros(Dn-1,1)] + Sign*randn(Ls,1);


	y = s + nf;		y = s + nf;

	%Sigx = 0.01;		%Sigx = 0.01;
	%ax = [1]; % bx and ax are filtering on n to produce x		%ax = [1]; % bx and ax are filtering on n to produce x
Line 45:		Line 37:
	%x = filter(bx, ax, n);%x = [x(Dx:(Ls)); zeros(Dx-1,1)] + Sigx*randn(Ls,1);		%x = filter(bx, ax, n);%x = [x(Dx:(Ls)); zeros(Dx-1,1)] + Sigx*randn(Ls,1);
	%x = x + Sigx*randn(1,Ls);		%x = x + Sigx*randn(1,Ls);

	system("aoss espeak 'Here is the noisy signal.'");		system("aoss espeak 'Here is the noisy signal.'");
	soundsc(y,Fs);		soundsc(y,Fs);

	N = 20; % Length of adaptive filter		N = 20; % Length of adaptive filter

	% LMS algorithm for adaptive noise cancellation		% LMS algorithm for adaptive noise cancellation

	h = zeros(N,1);		h = zeros(N,1);
	%mu = 1/(10Nvar(n));		%mu = 1/(10Nvar(n));
Line 62:		Line 54:
	h = h - mue(k)xk'/(xk*xk'); % For the previous line.		h = h - mue(k)xk'/(xk*xk'); % For the previous line.
	end		end

	% The signal estimate is in the vector e		% The signal estimate is in the vector e
	%speak('Here is the cleaned signal.');		%speak('Here is the cleaned signal.');

Frohro: Created page with ' % Demonstration of LMS algorithm for noise cancellation. % Rich Kozick, Spring 1997 % Rob Frohne's modifications for Aircraft Noise Cancellation. % modifications for Macintos…'

2010-11-30T18:38:40Z

Created page with ' % Demonstration of LMS algorithm for noise cancellation. % Rich Kozick, Spring 1997 % Rob Frohne's modifications for Aircraft Noise Cancellation. % modifications for Macintos…'

New page

% 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.)