I am working with certain speech enhancement algorithms, for instance to remove stationary noise or impulse noise from a speech signal. Filters such as those can enhance the speech signal, but they can also corrupt it, e.g., by distorting the speech information.
Now I wish to investigate how much the speech signal is distorted. I am not so much interested in amplitude differences (that can be easily determined), but more about distortions, such as frequency distortions. I guess these are nonlinear distortions?
Now a student of mine dug up the coherence function mscohere in Matlab. It looks promising, but it gives a frequency-dependent distortion measure.
Is there a way to capture the coherence function, or related algorithm in a single number, such that I can directly compare the distortion across different conditions?