Method one:

findpeaks function

PKS = findpeaks(data)

[PKS,locs] = findpeaks(data) — the number of peaks corresponding to PKS and locs

[…] = findpeaks(data,’minpeakheight’, MPH)– MPH sets the minimum peakheight

[…] = findpeaks(data,’minpeakdistance’, MPD)– MPD sets the minimum interval between two peaks

[…] = findpeaks(data,’threshold’,th)

[…] = findpeaks(data,’npeaks’,np)

[…] = findpeaks(data,’sortstr’, STR)

the command findpeaks is used to findpeaks of a vector that is greater than the value of two adjacent elements.

for example:

a=[1 3 2 5 6 8 5 3];

findpeaks(a),

returns 3 8

[v,l]= findbb2 (a),

returns

v=3 8

l=2 6

if a is a matrix, the values and locations of the peaks are listed in column search order.

For more information, see Help FindPeaks

Disadvantages:

You can only find the peak, you can’t find the trough.

Reproduced indicate the source: http://write.blog.csdn.net/postlist

Method 2:

IndMin=find(diff(sign(diff(data)))> 0) + 1;

IndMax=find(diff(sign(diff(data)))< 0) + 1;

where,

IndMin, data(IndMin) corresponds to the trough data

IndMax,data(IndMax) corresponds to the crest data

```
>> a=[1 3 2 5 6 8 5 3]
a =
1 3 2 5 6 8 5 3
>> IndMax=find(diff(sign(diff(a)))<0)+1
IndMax =
2 6
>> a(IndMax)
ans =
3 8
>> IndMin=find(diff(sign(diff(a)))>0)+1
IndMin =
3
>> a(IndMin)
ans =
2
```

Reprint with reference to:

http://write.blog.csdn.net/postlist

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