How to get the postions of peak on the plot?

Hello everyone, i maked a program that a use this files:

https://sites.google.com/site/negocindosica/DadosHPLC.rar?attredirects=0&d=1

the program is:

function [names,tr,X] = dadoshplc(r1,r2)
% Esta função importa os cromatogramas do HPLC
% Importar usando r1=1597 e r2=3156

[names, path] = uigetfile({'*.txt','datefiles(.txt)'},'MultiSelect','on','SelectFiles..');
% Abre uma janela para selecionar os arquivos

cd(path); % Indica o caminho a ser selecionado e traz para o current folder
if ischar(names) == 1 % Se for importado apenas um arquivo
    num = 1;
else
    num = length(names); % Se for importado mais de um arquivo
end

for i = 1:num
    if num <= 1
        files = names; % Se for importado apenas um arquivo
    else
        files = names{i}; % Se for importado mais de um arquivo
    end
    
tr = dlmread(files,'\t', [r1 0 r2 0]);  % Importa o eixo das variáveis: tempo de retenção.
x = dlmread(files,'\t',[r1 1 r2 1]); % Importa as intensidades.
X(:,i) = x(:,1);

% Etapa de plotagem
    subplot(1,2,1)
    plot(tr,x) % plot de um cromatograma
    axis tight
    xlabel('tr/min')
    ylabel('mV')
    subplot(1,2,2)
    plot(tr,X) % plot de todos os cromatogramas
    axis tight
    xlabel('tr/min')
    ylabel('mV')
    pause(0.5);
    legend('Aguarde')
    
%legend('click Aqui')
%keydown = waitforbuttonpress;
close all
end
X = X';
close all
figure
plot(tr,X)
axis tight
xlabel('tr/min')
ylabel('mV')

end

and the output is:

I wanna create a program that get the positions these 5 peaks on the grafic. for example, in this program the position is:

pico1 = 780:870;

pico2 = 910:1020;

pico3 = 1130:1220;

pico4 = 1221:1330;

pico5 = 1331:1500;

Someone can help me?

[madhan ravi]

doc findpeaks

[Rodrigo Franco]

thanks man, but i dont know how to get only these 5 peaks

when i use findpeaks(a(:, 2)) for exemple and the output is:

and i dont know whats means this parameter 2 findpeaks(a(:, 2))

[darova]

use MinPeakHeight property

findpeaks(y,'MinPeakHeight',1)

Answer 1

[Image Analyst]

Attach your file(s) here, with the paper clip icon, not in Google (we're not going to go there), if you need more help.

When you say a(:, 2), it means you're extracting the second column only - that's just super basic MATLAB indexing.

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You might be interested in my attached demo that fits a specified number of Gaussians to a signal.