We found that using Java Native Interface (JNI) to C can improve the overall performance by about 20%.

Current implementation based on the basic ICA model discussed below is able to separate more than 10 sources successfully.

Given a machine (i.e. your PC or a robot) observed mixtures of two signals (shown in the Figure 1),

Figure 1      Mixtures of two signals

How can the machine know original ones?

The "Impossible Mission"

Y1 = a * X1 + c * X2
Y2 = b * X1 + d * X2

One way to accomplish this "impossible mission" is to apply Independent Component Analysis to these mixtures. If you do so, you can have an "estimation" shown in the Figure 2.

Figure 2      Estimated signals

Original signals can be viewed here (new window)

1. The direction of one estimated signal is completely wrong!

Luckily, it does not matter here. See an example below:

The Original signal:

The "100% Wrong" signal:

These examples were obtained from here.

1. Play these files first.

               

(all in WAV format, about 51kB in size)

Can you identify some?

2. Let us see what Independent Component Analysis can do.
Try these estimated audio files.

               

(all in WAV format, about 51kB in size)

3. These are original audio signals.

               

(all in WAV format, about 51kB in size)

These examples were obtained from Sun (JavaSound) and recorded from various TV programmes including BBC Documentations, BBC News, Five News and ITV I'm A Celebrity 2004. Contents might be modified for this experiment.

1. Play these mixture files first.

                           

Play all mixture signals using Windows Media Player (8.0 for XP),
you only need to download (Save As) this playlist.

(all in WAV format, about 40kB in size)

2. Try these estimated audio files after applying Independent Component Analysis. Note that noises were added in original signals

                           

Play all estimated signals using Windows Media Player (8.0 for XP),
you only need to download (Save As) this playlist.

(all in WAV format, about 40kB in size)

3. These are original audio signals. As they were recorded from standard microphones, significant noises were added.

                           

Play all original signals using Windows Media Player (8.0 for XP),
you only need to download (Save As) this playlist.

(all in WAV format, about 40kB in size)

More references are available in Selected Literature

This page is intended to give you a brief overview of my work so far.

However, I have not spent much time writing this page, as I am busy with this project.

Please contact me if you have any question.


Yu Song