Hi,
I am assuming that the original audio signal is named ‘org’ & the modified (through steganography) audio signal is named ‘mod’.
Now, it is to be understood that noise is not a characteristic (like frequency, amplitude etc.) of sound (or in this case, audio signal), so it is not possible for any kind of software or electronic tool to straightaway extract noise from an audio signal unlike amplitude, frequency etc.
However, we can apply various filtering techniques to an audio signal. Say, after applying filtering to ‘org’ & ‘mod’, the filtered signals obtained are ‘filter_org’ & ‘filter_mod’. You can remove the filtered components from original audio signals, what you are left with is the noise itself, use these noise audio signals to serve your purpose.
Disclaimer: every filtering technique may give slightly different kind of filtered audio signal & therefore, noise obtained from each of the filter will be different.
To know more about noise filtering in MATLAB, refer the following links:
- How to pass a audio signal through a filter
- extract noise and apply it at other data
- how to separate noise from signal
- how to extract noise amplitude from a signal
