How to extract mean frequency from continuous wavelet transform (CWT)

6 次查看（过去 30 天）

Brent 2017-3-22

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/331233-how-to-extract-mean-frequency-from-continuous-wavelet-transform-cwt

评论： Christoph Mohl 2023-11-27

Hello,

I have used the cwt function in Matlab 2017a to create a scalogram of an electromyography (EMG) signal. My goal is to compare the time varying mean frequencies of different EMG signals. The issue is that I'm not sure how to use the complex double output (wt) to calculate a usable mean frequency 1D waveform.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Santhana Raj 2017-3-22

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/331233-how-to-extract-mean-frequency-from-continuous-wavelet-transform-cwt#answer_259821

Hi,

If your question is to how to get useful information from the complex matrix of 'wt', then use the command 'abs' to get the absolute magnitude of the complex variable.

If your question is to how to extract mean data from a vector, then compute the average of the signal. You can do the same for different scales in your wt or overall average value across all scales.

Hope this helps.

Raj

4 个评论
显示 2更早的评论隐藏 2更早的评论

Brent 2017-11-27

在 MATLAB Online 中打开

Hi Jungyeon. Below is the code I used to calculate IMNF. It's based on the paper above and uses the [wt, f, coi] outputs from the cwt function. you'll likely need to filter the IMNF as the outcome is quite noisy.

wta=abs(wt);
s_max=length(f);
s=1:s_max;
w0 = f(1);
 for i=1:size(wta,2)
    w=w0./(s(2:end));
    IMNFi(i)=trapz(w',w'.*wta(2:end,i))./trapz(w',wta(2:end,i));                    
end