extrema.m, extrema2.m

Search all extrema points of a time series or a surface with/without NaN's.

Description

Search all the maxima and minima points (peaks) in a time series (vector) or a surface (matrix), via columns, rows and crossing diagonals, ignoring NaN's elements.

USAGE:

[zmax,imax,zmin,imin]= extrema2(peaks);

where zmax (zmin) are the maxima (minima) elements and imax (imin) their linear index (check IND2SUB).

They come with the examples on the screenshot.

These are the same files as EXTREME.M and EXTREME2.M, but updated.

Acknowledgements

This file inspired Bi Dimensional Emperical Mode Decomposition (Bemd), Find Depressions, Minima Maxima3 D, and Extrema.

• MATLAB release: MATLAB 7 (R14)

[Rafael Freire]

Do you have an option to put the sensitivity of the peaks? to only get the higher ones....

[Kumar]

 

[M@lik Ali]

Hi all i have to calculate the LUV color components any one can help me...
Thanks in Advance..

[Camille Couzi]

Hola Carlos!
Thanks for your contribution.
I am having some issues though... I am using your function inside a script which uses fminsearch also... and getting the following error message:

Maximum recursion limit of 500 reached. Use set(0,'RecursionLimit',N)
to change the limit. Be aware that exceeding your available stack space can
crash MATLAB and/or your computer.

Error in extrema

Error while evaluating uicontrol Callback

Help! How do I solve this problem!
Gracias y muchos saludos!

[raj]

{surf(T,f,G'), shading interp
[Gmax,imax,Gmin,imin] = extrema2(G);
hold on
plot3(T(imax),f(imax),Gmax,'bo')
for i = 1:length(Gmax)
text(x(imax(i)),y(imax(i)),zmax(i),[' ' num2str(zmax(i))])
end
hold off}
My problem is the T,f,G are of different sizes and an error comes up saying '??? Index exceeds matrix dimensions.' any suggestions please help

[raj]

I have a problem while using it for an array can u explain an example as u did it for a vector please, I am a begginer with this stuff

[Luke Winslow]

 

[Luke Winslow]

 

[Anusha]

Can someone help me on how to adapt this to detect maxima and minima points on an object edge?

[Thomas]

much better than findpeaks for my data thanks so much!

[Onkar Singh Gujral]

 

[Aslak Grinsted]

Nice. There is also the built-in function findpeaks from the signal processing toolbox:

http://www.mathworks.se/help/toolbox/signal/findpeaks.html

[Rafael Freire]

Perfect for finds maximun and minimuns in a surface! Great Job

[Rick Towler]

Nice work.

[Rick Towler]

 

[Sanjeev]

Excellent work

[joe saucer]

hey guys.. is their anyway for this program to just give me the biggest maxes? my plot has many, many small peaks.. also, can you store these as variables?

[Yin Wang]

Excellent work, this is exactly what I need.

[angeles sierra]

kiero agregar un linck a mi fotolog
pero no se como aserle

[Carlos Adrián Vargas Aguilera]

You are so right Dimitri! I've made a terrible translation from spanish, I meant "extrema points"... Ouch! I need to change even the name!

[Dimitri Shvorob]

It might be helpful to briefly explain the exact definition of 'extreme points'.

[Jacob Eisenstein]

thanks, very helpful.

[Johnny Job]

Well done.

[Carlos Adrián Vargas Aguilera]

Thanks JaeKyu Suhr!, new file with bug fixed in about 1 day...

[JaeKyu Suhr]

This is excellent, but when i use extreme2.m
There is an error related to a variable "indx".
Therefore, I put a little bit of code in "extreme.m" like this

% NaN's:
inan = find(isnan(x));
if ~isempty(inan)
indx = 1:Nt;
indx(inan) = [];
x(inan) = [];
Nt = length(x);
%%----added code
else
indx = 1:Nt;
%%%%%%%%%%%%%%%%
end

[cloves souza]

e muito legal

[Sasha Trevizo]

The author sure had a headache after he finished this, so, thanks for avoid it to me! It works really good!