Area between the peak of the signal
1 view (last 30 days)
Show older comments
Yew Jen Chong
on 17 Jun 2022
Commented: Star Strider
on 22 Jun 2022
Hi,
Anyone know how to calculate for the area of torque between the peak (triangle label) of the signal?
Can anyone please help me?
Thank you.
4 Comments
Star Strider
on 17 Jun 2022
How did you identify those specific peaks?
I am having problems reproducing that with findpeaks.
Accepted Answer
Star Strider
on 18 Jun 2022
I had to tweak the code slightly to get the result I needed for the ‘areav’ and ‘absareav’ calculations.
Try this —
% opts = weboptions('ContentType','text');
% W = webread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1035225/s.m', opts)
T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1035230/signal.csv', 'VariableNamingRule','preserve');
t = T1.('Time [s]');
Fs = 1/t(2);
Torque = T1.('Torque [Nm]');
env = envelope(Torque, 100, 'peak');
Lv = env >= 5;
LastIdx = find(Lv,1,'last');
[pksRT_after,locsRT_after] = findpeaks(Torque,'MinPeakDistance',100,'MinPeakProminence',20,'MinPeakHeight',6);
locsRT_afterv = [locsRT_after; LastIdx];
for k = 1:numel(locsRT_afterv)-1
idxrng = locsRT_afterv(k) : locsRT_afterv(k+1);
t_midrng(k) = median(t(idxrng)); % Used In 'text' Call
areav(k) = trapz(t(idxrng),Torque(idxrng)); % Area
absareav(k) = trapz(t(idxrng),abs(Torque(idxrng))); % Absolute Area
end
% buffer(areav,10)
% buffer(absareav,10)
figure
plot(t(Lv), Torque(Lv))
grid
hold on
plot(t(locsRT_after), pksRT_after, '^r')
% plot(t, env, '-r')
hold off
text(t_midrng, pksRT_after/2, compose(' \\leftarrow Area = %.4f',areav), 'Horiz','left', 'Vert','middle', 'Rotation',90, 'FontSize',9)
The loop uses trapz to calculate the areas between the locations denoted by the red triangles. The code then plots and labels them. (It uses the envelope function to define the area of interest in the signal for the plot.)
.
2 Comments
More Answers (0)
See Also
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!