Hi Phudit,
You can refer to documentation of hold function to plot 2 different plots on same figure. To calculate the common peak, you can first find the common indices where a peak exists for both the datasets and then find the value of the peaks occured at those indices. The following code illustrates this idea:
pure_brain = readmatrix('Pure Brain Spectra.csv');
[pks,locsBr] = findpeaks(pure_brain(:,2));
LvBrain = pure_brain(locsBr,2)>1E+4; % 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)>1E+4; % 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
Hope this helps!
