findpeaks() neglecting the high amplitude peaks.Does not work as exptected

I am attaching herewith the data i am working with. Findpeaks() is not detecting the highest amplitude peaks. Attached is the data I am working with. Following is the code:

file = 'forRef_2.xls';

col = xlsread(file,'J:J');

peaks=findpeaks(col);

[pks,locs] = findpeaks(col);

%both on same plot
figure

plot(col,'r')

hold on

plot(locs,pks,'pg', 'MarkerFaceColor','b')

legend('original','peaks')

[Andrew Newell]

I can't reproduce your result. The array col should be a vector, but it has dimensions 624 x 7, so I get an error from findpeaks.

[preeti visweswaran]

I get an image like the one attached.

[Andrew Newell]

And do you use exactly the code you have provided above? Or do you select one of the columns in col?

[preeti visweswaran]

yes,same code

Answer 1

[Andrew Newell]

When I try this code, I get 7 plots, and figure 7 looks like your figure except that all the peaks are correctly identified:

file = 'forRef_2.xls';
col = xlsread(file,'J:J');

for ii=1:size(col,2)
  peaks=findpeaks(col(:,ii));
  [pks,locs] = findpeaks(col(:,ii));
  %both on same plot
  figure
  plot(col(:,ii),'r')
  hold on
  plot(locs,pks,'pg', 'MarkerFaceColor','b')
  legend('original','peaks')
end

[preeti visweswaran]

This code gave me the same results as mine.I still dont see the highest peaks of amplitude 0.88 identified. Can you attach the image

[Image Analyst]

Do you see this:

Looks like it's getting the peaks you'd want. Are you saying you don't get the above plot?

[preeti visweswaran]

no,i used your code and get the output as the image attached. Did you change the data ?

[Andrew Newell]

Image Analyst got the same image I did. Have you tried clearing your memory before running the code?

[preeti visweswaran]

I cleared the command history and workspace,still see the same.I am using an older version.What could be the reson

[Andrew Newell]

Which version are you using?

[Image Analyst]

Please attach images, like PNG files, with the image icon.

rather than attaching .fig files which just causes extra work for us. We have to save the fig filt to disk, then leave the browser, go into MATLAB, open the fig file because clicking on the fig file in the browser just shows gibberish. Make it easy for us next time. For the benefit of others, I've done all that and here is your image.

[preeti visweswaran]

I could plot it as mentioned by Andrew.The problem is with the matlab version i am using.I tried in 2016 version,it worked perfect.Thanks for your help!

[preeti visweswaran]

sorry for the inconvenience with fig files.I will attach png images in future

[Andrew Newell]

Glad to hear that you got it working!

[preeti visweswaran]

I would be grateful to you if you could advise me another problem posted in https://www.mathworks.com/matlabcentral/answers/336003-peak-detection-without-using-findpeaks