peakdetect.m

Generates and graphically displays the positive and negative polarity peak index vectors of input.

Description

peakdetect.m generates and graphically displays the positive and negative polarity (concave down and up) peak index vectors of an input signal vector. Positive and negative polarity peaks occur at points of positive to negative and negative to positive slope adjacency, respectively. The typically rare contingencies of peaks occurring at the lagging edges of constant intervals are supported.

Example:

[p,n]=peakdetect([-1 -1 0 1 0 1 0 -1 -1])

p =

     4 6

n =

     1 5 8

• MATLAB release: MATLAB 6.0 (R12)

[Eric Shain]

Seems to work nicely. The function plots automatically which can get in the way. Easy to disable but it requires a bit of editing.

[Ingo Wenningmann]

 

[Maurice Masequesmay]

Great! However, this function does not find the midpoint when consecutive peaks are
exactly equal. For example it does not handle [0 0 0 0 1 1 1 1 0 0 0 0] well.
Add-on suggestion:
Given a continous plot of x & y, it would be nice if the function could interpolate a
corresponding x value for a particular peak.

[Andre Frotta Muller]

Very good!!!!
Fast!!!
Thanks, Tom McMurray

[zhe wu]

 

[Zoltan German]

 

[Dániel Hillier]

As Maurice Masequesmay already suggested, the function does not find the midpoint when consecutive peaks are exactly equal. It would also be better to have a separate function for min and max - both could give back the actual signal value at extrema.

[Claudia Lerma]

 

[J W]

Overall this program was very similar to peaks and worked well. I would be like to be able to measure the absolute vertical distance between peaks and corresponding troughs? Is this possible?

[Bernard Simons]

Daniel and JW, go and download extreme.m