<< Chapter < Page Chapter >> Page >
This module details the implementation of a blind source separation system using fast ICA.

Blind source separation via ica:

Implementation

In order to implement our design to enable the separation of two audio signals, we require two microphones and a processing computer with audio output capabilities. When two microphones are present in an environment with two sources, then they will record a mixing of both these signals, weighted by coefficients base on distance away from the microphone (remember that as a signal is further away from a recording source, the quieter it will be).

The mixed signal inputs of these microphones must then be imported into a processing computer that is able to run code based in C or MatLab (or potentially any other language, but the most efficient algorithm is run in MatLab and C).

The model for these mixed signals can be represented in matrix notation by:

x = A s

As we can see, the signal vector is multiplied by some mixing matrix A. Therefore to isolate the signals s based on the mixed signals x we must find an inverse matrix A-1. To do this we implement a piece of Matlab code known as FastICA . The math behind the algorithm is explained elsewhere but the most important piece of code, the iteration to find the inverse mixing matrix, is displayed here:

% Take a random initial vector of length 1 and orthogonalize it

% with respect to the other vectors.

if initialStateMode == 0

w = randn (vectorSize, 1);

elseif initialStateMode == 1

w=whiteningMatrix*guess(:,round);

end

w = w - B * B' * w;

w = w / norm(w);

wOld = zeros(size(w));

wOld2 = zeros(size(w));

% This is the actual fixed-point iteration loop.

% for i = 1 : maxNumIterations + 1

i = 1;

gabba = 1;

while i<= maxNumIterations + gabba

if (usedDisplay>0)

drawnow;

end

% Project the vector into the space orthogonal to the space

% spanned by the earlier found basis vectors. Note that we can do

% the projection with matrix B, since the zero entries do not

% contribute to the projection.

w = w - B * B' * w;

w = w / norm(w);

if notFine

if i == maxNumIterations + 1

if b_verbose

fprintf('\nComponent number %d did not converge in %d iterations.\n', round, maxNumIterations);

end

round = round - 1;

numFailures = numFailures + 1;

if numFailures>failureLimit

if b_verbose

fprintf('Too many failures to converge (%d). Giving up.\n', numFailures);

end

if round == 0

A=[];

W=[];

end

return;

end

% numFailures>failurelimit

break;

This iteration will guess a row of the demixing matrix (w in the code) and then run through a loop until it finds a projection that agrees with the statistical analysis behind the decoding.

After running on the supplied mixed signals, the program will output what it thinks are the two original sources and the demixing matrix. We can then use these outputs to complete a variety of tasks such as removing noise from the original signals, matching the original signals with other signals to detect base elements of the mixed signal, or even just simply outputting the original signals through a speaker system.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play




Source:  OpenStax, Elec 301 projects fall 2007. OpenStax CNX. Dec 22, 2007 Download for free at http://cnx.org/content/col10503/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Elec 301 projects fall 2007' conversation and receive update notifications?

Ask