How can I plot 2 data in 1 graph and find common peak

How can I plot 2 data in 1 graph and find common peak

Common peak is a peak that appear at the same X coordinate but have different Y value

pure_brain = readmatrix('Pure Brain Spectra.csv');
[pks,locs] = findpeaks(pure_brain(:,2));  
x = 1:size(pure_brain,1);
Y = pure_brain(locs(Lv),2);
Y = Y .* 100/max(Y);
[pks_min,pks_max] = bounds(pks)                                         % Minimum & Maximum Values Of ‘pks’
figure
Lv = pure_brain(locs,2)>1E+4;                                           % Set Threshold = 1E+4
% Lv = pure_brain(locs,2)>1;                                              % Set Threshold = 1
%plot(x(locs(Lv)), pure_brain(locs(Lv),2), '.r')
plot(x(locs(Lv)), Y, '.r')
grid
title('Pure brain peak');


%AB=unique(pks);
%YB1=AB(end);                   %1Y
%YB2=AB(end-1);                 %2Y
%YB3=AB(end-2);                 %3Y

%EB1=find(pks==YB1);
%XB1=locs(EB1);

%EB2=find(pks==YB2);
%XB2=locs(EB2);

%EB3=find(pks==YB3);
%XB3=locs(EB3);



%SYB = [ YB1 YB2 YB3 ];
%SXB = [ XB1 XB2 XB3 ];

Answer 1

[Pavan Guntha]

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!

[Phudit Kanittasut]

Your answer is so helpful ,thank you , but I have one question I open common and I cant get the location of the common peak.