How to find common peak and save it location

How can I fine common peak? Ex. When I have 2 data that data 1 have peak at X axis location at 3 ,4 ,5 ,6 ,7 and data 2 at 1 , 4 ,6 , 8 ,10 , so the common peak is at 4 , 6 , but if I dont know where the common peak occur , how can I find the data that occur at the same X coordinate .

clear
pure_brain   = readmatrix('Pure Brain Spectra.csv');
[pks,locsBr] = findpeaks(pure_brain(:,2));  
LvBrain = pure_brain(locsBr,2)>0;            % Set Threshold = 1E+4
xBrain  = 1:size(pure_brain,1);
YBrain  = pure_brain(locsBr(LvBrain),2);
YBrain  = YBrain .* 100/max(YBrain);
[pks_min,pks_max] = bounds(pks);                % Minimum & Maximum Values Of pks
figure
pure_Liver    = readmatrix('Pure Liver Spectra.csv');
[pks,locsLiv] = findpeaks(pure_Liver(:,2));  
LvLiver = pure_Liver(locsLiv,2)>0;           % Set Threshold = 1E+4
xLiver  = 1:size(pure_Liver,1);
YLiver  = pure_Liver(locsLiv(LvLiver),2);
YLiver  = YLiver .* 100/max(YLiver);
plot(xBrain(locsLiv(LvBrain)), YBrain, '.r')
hold on
plot(xLiver(locsLiv(LvLiver)), YLiver, '.b')
hold off
grid
% To find common peaks considering the threshold of 1E+4:
lB = locsBr(LvBrain);
lL = locsLiv(LvLiver);
s  = max(length(lB), length(lL));
locsLivNew = [lL; false(s-length(lL),1)];
locsBrNew  = [lB; false(s-length(lB),1)];
common     = locsLivNew == locsBrNew;           % Find the common location of peaks

[Mathieu NOE]

hello

I looked at the data , and was wondering if the peaks need to be "exactly" at the same x location or must be close (to a certain amount)

I ask because most of the peaks are not exactly at the same locaction, and some (few) minor peaks are.

so what are we looking for ?

distant peaks

matching peaks (found only those)

[Phudit Kanittasut]

It must be close to each other.

So how can I find it ?

Thx

[Mathieu NOE]

hello

yes sure, but how close ? we need a "window" length to be defined

[Image Analyst]

If you're up for it, Mathieu, just define one as a variable and continue on with the solution

windowWidth = 15; % whatever....
% Now code to call findpeaks() and find out which peaks 
% are within windowWidth of peaks in other signal....

Then he can change the number to whatever he wants.

[Mathieu NOE]

@Image Analyst

thank you for the tip, but I'd like to see first the OP clarify his needs - have to work a bit for my company sometimes !

Answer 1

[Image Analyst]

Try experimenting around with ismember().