Find peaks in data without using signal processing tool

Hello Guys,

I am working on a set of data, attached.

I am using MatlabR2021b, I don't have signal processing tool. Therefore can't use peak function.

I need to find:

1. Total number of peaks in data
2. What are the corresponding values of eack peak

Would appreciate if anyone can suggest a solution.

Please let me know if my question is not clear.

Thanks

Answer 1

[Star Strider]

The findpeaks function is in the Signal Processing Toolbox, and since you do not have access to it, use the core MATLAB islocalmax function instead (introduced in R2017b) —

T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1059360/peaktest.xlsx', 'VariableNamingRule','preserve');
Time = T1.Time;
spike2 = T1.spike2;

Lv = islocalmax(spike2, 'MinProminence',1);                 % Choose The Name-Value Pair Arguments To Return The Peaks You Want

TotalNrOfPeaks = nnz(Lv)

TotalNrOfPeaks = 8

PeakTable = table(Time(Lv),spike2(Lv), 'VariableNames',{'Spike2Time','Spike2Amplitude'})

PeakTable = 8×2 table
    Spike2Time    Spike2Amplitude
    __________    _______________

         8              105      
        11              111      
        16              111      
        23              120      
        38              133      
        46              111      
        92              105      
        96              106      

figure
plot(Time, spike2)
hold on
plot(Time(Lv), spike2(Lv), '^r')
hold off
grid

.

Answer 2

[Sam Chak]

Hi @Harsimran Singh

If the data is not too large, you can test features of the findpeaks() function in this forum.

Else, you can find some peakfinder algorithms in FileExchange.

[data] = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1059360/peaktest.xlsx');
plot(data.Time, data.spike2)

[pks, locs] = findpeaks(data.spike2)

pks = 8×1

105 111 111 120 133 111 105 106

locs = 8×1

8 11 16 23 38 46 92 96

num_of_pks = length(pks)

num_of_pks = 8

[Harsimran Singh]

Thanks Sam, for sugesstion, Peak function/signal processing tool does not works for MatlabR2021b..