signal processing and paek counts

i am simply trying to wrote an algorithm to detects the peaks on a certain ecg signal without using built-in function (findpeaks)

my code works just fine for the full period of the signal which is 540000 sample

but i need the code to count the peaks for each 1 min (6000 sample) and save them into an array

i used the code below but it always shows me the same error:

{

index in position 2 exceeds array bounds. Index must not exceed 1.

Error in algorithm (line 124)

max_h = max(ecgsig(ii,kk));

}

for ii =(0:6000:540000)

max_h = max(ecgsig(ii,ii+6000));

thresh = mean (ecgsig(ii,ii+6000));

poss_reg =(ecgsig(ii,kk)>thresh*max_h)';

left = find(diff([0 poss_reg])==1);

right = find(diff([poss_reg 0])==-1);

for i=1:length(left)

[R_value(i) R_loc(i)] = max( ecgsig(left(i):right(i)) );

R_loc(i) = R_loc(i)-1+left(i);

end

R_loc=R_loc(find(R_loc~=0));

f = length(R_value);

t1=(length(ecg_sm(ii,ii+6000))/fs)/60

bpm=f/t1

end

so what is the problem and how can i solve it?

any help is much appreciated

[Mathieu NOE]

hello

can you share your ecg signal ?

tx

Answer 1

[Image Analyst]

Why can't you use findpeaks()? Do you not have the toolbox, or is this homework where you are supposed to reinvent the findpeaks function? If it's your homework, then please tag it as homework. If you can't use that function, I imagine there are others you can't use either, like movmax.

See What can be programmed "without any built-in functions" ? - MATLAB Answers - MATLAB Central

Your error message says you used kk

max_h = max(ecgsig(ii,kk)); 

while the line in the larger snippet of code you posted says you're using ii

max_h = max(ecgsig(ii,ii+6000));

Which is it? Or is it both and you just posted a snippet from the wrong lines of your program?

So what is the value of kk? Evidently it's more than 1. Why do you even have a 2-D image for your ecg signal anyway? Shouldn't it be a 1-D signal, so you wouldn't even have a column index like kk or ii+6000?

Maybe you mean

max_h = max(ecgsig(ii : ii+6000));

to specify a range of elements rather than a single (row, column) location in an image.

If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:

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