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The results to several trials in varying cases.

Results

Note: all supporting code needed for the main Matlab codes to work is attached below

Ideal case: matlab

Like last year, fastICA works well in MATLAB. For example, mixing and then separating a siren and a voice using MATLAB exclusively works quite well as can be seen in the figure below. fastICA in this very ideal environment was able to separate the two mixed signals into the independent sources of a voice, the lower left spectrogram, and a siren, the lower right spectrogram.

For a better grasp of our results, here are the sound files of the mixed signal, isolated siren, and isolated voice, respectively. Also, the MATLAB code used for this trial is also attached after the sound files.

Real time acoustic mixing case: fast ica used

Performing this same feat using an actual microphone, however, fails. For example, we recorded two sources, voice and tone, simultaneously with two microphones which resulted in the spectrograms of the two mixed signals shown below. Once these mixed signals were passed through the fastICA algorithm, the results were terrible source isolation. As you can see by the lower two spectrograms of the figure below, the independent components look almost the same as the mixed signals we started out with.

Here are the sound files for the two mixed signals and the two "separated sources". The code use to carry out this trial is last.

Real time acoustic mixing: stfica or fastica used

We conjecture two reasons to explain why fastICA is unsuccessful in this scenario.

First, atmospheric and room conditions will change the signal using convolutive operations, rather than the scaling ones that fastICA implements. Second, the characteristic response of the microphones both changes the signals and varies from microphone to microphone, introducing both inaccuracy and imprecision. The original ICA technique, fastICA, does not automatically account for these deviations. Also, although the fastICA does implement a single stage of prewhitening, it may not be enough to alter the input mixed signals so that they look independent of one another in time and space, therefore satisfying the fastICA assumption of independent inputs. So we decided to use the STFICA model in order to account for the convolutive matrix involved and to allow for a user-specifiable number of prewhitening stages.

It was at this time that we experimented with the number of prewhitening stages by setting an iteration level and then watching the output spectrograms for each iteration. Our group could not find a pattern or relation between the iteration number of the prewhitening and the effectiveness of the source isolation, but it was definitely observed that more than stage helps in the source isolation process. Sometimes one iteration would result in some separation, and then the next few iterations did not result in any source separation at all.

Using the STFICA algorithm in some real world cases worked out better than the original fastICA procedure. In one experiment, we produced a pure tone and recoded the source with two microphones. The expected sources that would be isolated were the tone and any ambient noise. The mixed signal of each of the two microphones was passed through the fastICA code and also separately through the STFICA code for comparison. Even with this very simple case, fastICA produced poor results as can be seen in the middle two spectrograms of the output independent components. The spectrograms look almost identical to the original mixed signals that were the inputs. STFICA, on the other hand, separated the pure tone from the white noise exceptionally well. As can be seen in the last row of the figure, the tone (located on the bottom left) was well isolated from the ambient white noise (spectrogram on the bottom right).

Here are the sound files for the two mixed signals, the two "separated signals" produced by fastICA, and the two separated components produced by the STFICA.

In more complicated situations where the sources were multiple human speakers, a human speaker and a tone, or other, we did not achieve the same success. The modified algorithm sometimes made one voice more prominent than the other, but it appeared to be doing filtering in a way that was not achieving the desired result. The success here was not as great as with the simple tone with noise case.

Questions & Answers

explain and give four Example hyperbolic function
Lukman Reply
_3_2_1
felecia
⅗ ⅔½
felecia
_½+⅔-¾
felecia
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
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Ifeanyi
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x*x=2
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2+2x=
felecia
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
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Harshika
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corri
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Only Reply
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4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
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Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
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Brenna
Need help solving this problem (2/7)^-2
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x+2y-z=7
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-1
Shedrak
the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
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A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
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Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
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why surface tension is zero at critical temperature
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s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
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. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
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Source:  OpenStax, Elec 301 projects fall 2008. OpenStax CNX. Jan 22, 2009 Download for free at http://cnx.org/content/col10633/1.1
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