Finding local minima for a signal

You're probably okay with your data, but beware of findpeaks() if your max or min spikes have flat tops or bottoms. It will give only the first index. In that case you want to use the imregionalmin() function from the Image Processing Toolbox. Just look at this example with a min that has a flat bottom:

data = [ 1 3 4 2 2 2 4 4 5 6]  % Flat bottom with value of 2 from indexex 4-6
[peakValues, indexesOfPeaks] = findpeaks(-data)
peakValues = -peakValues
minIndexes = imregionalmin(data)
data =
     1     3     4     2     2     2     4     4     5     6
peakValues =
    -2
indexesOfPeaks =
     4
peakValues =
     2
minIndexes =
     1     0     0     1     1     1     0     0     0     0

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neamah al-naffakh 2016-8-9

hi mate, thanks for your effort i will check your solution and reply back , but do you mind have a look to this question please?

http://uk.mathworks.com/matlabcentral/answers/298931-calculating-the-mfcc-and-bfcc-for-a-signal

Image Analyst 2016-8-9

I don't know how to answer that question.

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Answer 4

shima tavakoli 2018-2-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/298923-finding-local-minima-for-a-signal#answer_304970

my signal is asymmetric and its negative parts are different. how to deal with negative parts peaks then? cant negative the signal in this case!

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Image Analyst 2018-2-13

Who knows? You forgot to read this and forgot to attach your signal and a screenshot of it, so there's not much I can say, other than to write custom code to deal with it.

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