MATLAB: The fastest way to find local minimum

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What is the most efficient/fastest way to find the circled local minimum below, the lowest minima between two highest peaks? The graph was created by plot(x,y).

Best Answer

Invert your signal

invertedSignal = max(signal(:)) - signal;

Now valleys will be peaks. Then call find peaks.

Related Solutions

MATLAB: How to Find Prominence of Peaks

@Ephraim Bryski,

Yes, the prominence is the fourth (and optional) output argument of findpeaks().

[pks,locs,w,p]=findpeaks(Data);

returns the prominences in p.

[pks,locs,w,p]=findpeaks(Data,'MinPeakProminence',1000);

finds peaks with prominence >=1000 and returns the prominences in p.

MATLAB: How to restrict the Max Peak Height of findpeaks

If you don't want it to find peaks higher than some amount, just set those elements equal to the min. Actually it would be better to find the peaks and then "fall down" the peaks until they turn up again and then interpolate in from both sides, but that's more complicated even though it would be better. Maybe this simple way will do the job for you:

minValue = min(yourSignal);
tallPeakIndexes = yourSignal > someThreshold; % Whatever value you want.
yourSignal(tallPeakIndexes) = minValue;  % Or you can use someThreshold instead of minValue.

If that ends up finding spurious peaks at the edges of the flattened peak, then use the more robust second method I suggested.

Best Answer

Related Solutions

MATLAB: How to Find Prominence of Peaks

MATLAB: How to restrict the Max Peak Height of findpeaks

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