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Question on envelop_hilbert algorithm in BioSigKit
Hi Hooman,
Thanks for making the BioSigKit open for the scientific community. I have a few questions about the function 'envelop_hilbert.m'.
-
On line 113: you have this:
if ~isempty(nois_buf)
Because you initialized nois_buf with a zero array so I think it should be always true. So I wonder if you actually mean to check if there is non-zero values in the nois_buf? If it's the case, I guess we have to use a different condition checking. -
Line 88-93:
if threshold_style
THR_SIG = 4*mean(env);
end
nois = mean(env)*(1/3); % noise level
threshold = mean(env); % signal level
Here you set initial values for threshold, noise and signal level based on the mean of Hilbert envelope. As I understand, the envelope mean is 0 (from line 77 env = env(:) - mean(env);
) so all of those values will be 0. I just want to confirm with you if that is the case.
- Finally, just a general question. Do you have a reference for this algorithm somewhere so I can read in more detail the theory behind this?
Thanks again for you contribution. I'm looking forward to hearing from you.
Best,
Long