need help on continuous wavelet transform of ECG

[Nazurah88]

imageshac.kus

hi and good day,

im currently doing final project on electrocardiograph segmentation using hidden markov model
for the database i make use of the qt database which are available from Physionet.

first, i preprocess the data by doing baseline wonder removal and denoising, making use of wavelet(which im not sure is it the correct method)
the code i make use is as below:


%**************************************************************************
clc; clear all; close all;
%**************************************************************************
% Get Data & User Inputs
%**************************************************************************
File_Name = sel30.txt %% % ECG Text File
ECG_Data = load(File_Name); % Load The Text File
Time = ECG_Data,1); % First Column Of File
ECG_1 = ECG_Data,2); % Second Column Of File (lead 1)
ECG_2 = ECG_Data,3); % Third Column Of File (lead 2)
Time_Adjusted = Time; % Time In Seconds Already

%%%Eliminate Baseline Drift
Base_1=smooth(ECG_1,150);ecgsmooth1=ECG_1-Base_1;
Base_2=smooth(ECG_2,150);ecgsmooth=ECG_2-Base_2;


%%%apply Wavelet Transform

[C,L]=wavedec(ecgsmooth1,8,'db4');
[d1,d2,d3,d4,d5,d6,d7,d8]=detcoef(C,L,[1,2,3,4,5,6,7,8]);

%%%Denoise
[thr,sorh,keepapp]=ddencmp('den','wv',ecgsmooth1);
cleanecg1=wdencmp('gbl',C,L,'db4',8,thr,sorh,keepapp);

%%%apply Wavelet Transform

[C1,L1]=wavedec(ecgsmooth,8,'db4');
[a1,a2,a3,a4,a5,a6,a7,a8]=detcoef(C1,L1,[1,2,3,4,5,6,7,8]);

%%%Denoise

[thr1,sorh1,keepapp1]=ddencmp('den','wv',ecgsmooth);
cleanecg=wdencmp('gbl',C1,L1,'db4',8,thr1,sorh1,keepapp1);



i hope some one could help me to supervise whether im on the right path of ecg preprocessing or not.



then, i should proceed with mexican hat Continuous wavelet transform method and im totally lost. i think the coding should be as below,

c = cwt(cleanecg1,1:32,'mexh');

but im not sure because its not the same as what it shows in papers, journals, nor proceedings that make use CWT
i want the result to be as below:

**broken link removed**

but i have no one here at my university that could help me..

i really hope that someone could help me..if you could help me, please mail me at nurnazurah@gmail.com

your help and guidance really help me a LOT..
thank you very much!
really appreciate it!!!

 

[akss_here]

make it more simple...

if you have idea about sampling frequency

then you can proceed with zero phase 4th order bandpass Butterworth filter...

it will reduce noise and as well as baseline oscillation also..

 

[ht_patil143]

Hello Dear,
Send me your complete code along with ECG signal text file at ht_patil143@yahoo.com.
I will just go throgh it and then I will send you your code but modified code.