Why is my code identifies only few peaks?

Hello there,

I have a code that generates graph of two column vectors by plotting the peak values. The code works well except for a case where if i add mean to center my axis,it is plotting only first one or 2 peaks for the files. However, if i take off the the code in brackets which is to find mean ( a1 = XDATA - mean (XDATA); plot(TIMESTEPS, a1); ) the code works well identifying all the peaks. Can anyone help me out with this?

         >> %BATCH MODE
          files = dir('C:\Users\Deakin Uni\Documents\MATLAB\a\*.xlsx');
          fNames = {'90','110','150'};

          %for each file
          for k= 1: length(fNames)
             % extract file names
             fName = ['C:\Users\Deakin Uni\Documents\MATLAB\a\', fNames{k}];
             [XDATA, TIMESTEPS] = importfile(fName);
          a1 = XDATA - mean (XDATA);
          plot(TIMESTEPS, a1);
          [peakvals,peaklocs] = findpeaks(a1, 'minpeakdistance',50, 'minpeakheight', 0.00001);
          peaktime = TIMESTEPS(peaklocs);
          createfigure4(TIMESTEPS, a1, peaktime, peakvals)
          saveas(gcf,sprintf('chaitu%d.png',k));
          end

Looking for a quick answer

Thanks in advance

Answer 1

[Greg Dionne]

you probably should also subtract the mean from the value you passed to 'minpeakheight' if you want it to track the data.

[Chaitanya Bade]

I tried using the below code and it work. Any more suggestions?

%BATCH MODE
files = dir('C:\Users\Deakin Uni\Documents\MATLAB\a\*.xlsx');
fNames = {'90','110','150'};

%for each file
for k= 1: length(fNames)
   % extract file names
   fName = ['C:\Users\Deakin Uni\Documents\MATLAB\a\', fNames{k}];
   [XDATA, TIMESTEPS] = importfile(fName);
a1 = XDATA - mean (XDATA);
plot(TIMESTEPS, a1);
[peakvals,peaklocs] = findpeaks(a1, 'minpeakdistance',50, 'minpeakheight', mean (XDATA)-0.001);
peaktime = TIMESTEPS(peaklocs);

createfigure4(TIMESTEPS, a1, peaktime, peakvals)
saveas(gcf,sprintf('chaitu%d.png',k));
%exporting to a data file 
newdata = [TIMESTEPS,XDATA];
csvwrite('www%d.dat',k,newdata)                         
end

[Greg Dionne]

Glad it worked for you.

[Chaitanya Bade]

Also, do you know how can i run the csvwrite command in a loop. I have used the one mentioned above. It doesn't work. Any suggestions?

[Greg Dionne]

Probably best to ask a separate question for that (include what you tried and what's not working well). I've used xlsread and xlswrite but I'm not trying to write streamed output like you are.