Feature extraction using DWT and WPT

Hi,
Can anyone confirm if my method of feature extraction is correct or not? I have used DWT and later WPT to decompose and extract features from vibration signals.
For DWT, I used the following MATLAB functions:
Example:
x1= signal;
[cA1,cD1]= wavedec(x1,1,'db4');
...
plot(cA1); title('Level-1 Approximation Coefficients')
figure(1); subplot(313);
plot(cD1); title('Level-1 Detail Coefficients')
k1=kurtosis(cA1) %E.g of one parameter used to extract some features%Approximation%
k2=kurtosis(cD1) %details%
...
And other statistical parameters.
My extracted features, after being used as inputs for the ANN classifier, showed that approximations are better than details, and performed with a very high classification rate.
I haven't found a reason to reconstruct the signal or using any filters (i.e. Low and high filters)?!
MATLAB staff and experts, can you confirm my method or correct me please?

5 个评论

Any comment, please. I will be very happy with any comments or correction.
There is nothing obviously wrong with what you do or your result. If you provided your data, maybe we could tell more.
can i get that feature extraction using wavelet code
Dear Tubi
I think you have some error in subplot , Index must be a 3 -digit number of the format mnp
Sorry dear Tubi
Your expression for subplot is Correct .

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回答(1 个)

Bernhard Suhm
Bernhard Suhm 2018-3-25
You could try using wavelets, the basic documentation is here: https://www.mathworks.com/help/wavelet/ref/dwtfilterbank.wavelets.html. That requires the Wavelet toolbox though, which you could get via a trial.

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