Audio Filter GUI DEMO

Theodoros Giannakopoulos
Department of Informatics and Telecommunications
Univarsity of Athens, Greece
website: www.di.uoa.gr/~tyiannak

General

This demo provides a simple GUI for basic filtering of audio data. Using the GUI you can:

Load audio data stored in a .wav file.
Generate uniform noise in specific audio frequencies, using lowpass, highpass or bandpass digital filters.
Add the filtered noised to the original audio signal.
Remove the noise by inverse filtering.

The purpose of this DEMO is not to provide robust and sophisticated denoising algorithms, but simply to demonstrate some basic audio filtering processes in Matlab.

In the following figure a screenshot of the demo is shown.

In the first panel (row) you can see the plotted audio signal and the respective spectrogram (obviously the sampling rate of the signal is 16KHz).
In the second panen, the user can create filtered noise (i.e. uniform noise that has been filter using specific filters). Here, we have selected to create a high pass noisy signal (cut frequency = 4KHz). In the plots, the spectrogram of the produced noise is presented, along with the spectogram of the noisy signal (after the noise signal has been added to the original signal). Finaly, the user can also define the SNR ratio (in dB) of the noisy signal.
In the final panel, the user can execute the inverse filtering, listen to the result and view the inverse filter transfer function, along with the final (filtered) signal's spectrogram.