extrema.m, extrema2.m
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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.
Cite As
Carlos Adrian Vargas Aguilera (2021). extrema.m, extrema2.m (https://www.mathworks.com/matlabcentral/fileexchange/12275-extrema-m-extrema2-m), MATLAB Central File Exchange. Retrieved .
Comments and Ratings (54)
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Acknowledgements
Inspired: Microscopy Image Browser (MIB), MinimaMaxima3D, Extrema, findExtrema, Bi dimensional Emperical Mode Decomposition (BEMD), findDepressions, TeloTool - Terminal Restriction Fragment Analysis, Automatic pattern recognition of Head-And-Shoulder
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By definition there is only one global maxima and one global minima for a given curve. Your code finds the local maximas and local minimas. Maybe you can change your description to reflect that.
Is there away that we can get the max and min points in order (without being on a increasing or decreasing one)?
It works for trivial arrays with smooth data values. When I tested with noisy data, I got a lot of misses and bad indices/extrema values. Matlab's function findpeak from Signal Processing toolbox works way better.
good.
where is the support for function handle?
It would be great to get an example how you apply `extreme2` on the plot `imagesc(x,y,C)`. - - I can get the frame so I.
excellent tool
I run the function
[hmax,imax,hmin,imin] = extrema2(h)
where h is a 1x15 vector (h=[11717 6172 2963 574 867 1099 1384 1726 2045 2230 2900 3460 3547 1625 617]) and I get the following error:
Attempted to access smaxcol(:,1); index out of bounds because
size(smaxcol)=[0,0].
Error in extrema2 (line 73)
im = unique([smaxcol(:,1);smincol(:,1)]); % Rows with column extrema
Found it very useful. Thanks for this submission.
jghg
This one should be added to Matlab native code ... :)
Does the job of 'findpeaks' with less code, and can find minima with so much less hassle. Might as well be considered a 'required' add-on.
Simple and useful.
Using this across a broad range of applications, very handy.
how can I use this mfile to run over my image?
Thx, works great!
thank you
this saves me a day of coding...
Hello, does anybody know how to replicate those detected extrema points onto a grayscale image.
Thank You
Do you have an option to put the sensitivity of the peaks? to only get the higher ones....
Hi all i have to calculate the LUV color components any one can help me...
Thanks in Advance..
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!
{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
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
Can someone help me on how to adapt this to detect maxima and minima points on an object edge?
much better than findpeaks for my data thanks so much!
Nice. There is also the built-in function findpeaks from the signal processing toolbox:
http://www.mathworks.se/help/toolbox/signal/findpeaks.html
Perfect for finds maximun and minimuns in a surface! Great Job
Nice work.
Excellent work
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?
Excellent work, this is exactly what I need.
kiero agregar un linck a mi fotolog
pero no se como aserle
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!
It might be helpful to briefly explain the exact definition of 'extreme points'.
thanks, very helpful.
Well done.
Thanks JaeKyu Suhr!, new file with bug fixed in about 1 day...
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
e muito legal
The author sure had a headache after he finished this, so, thanks for avoid it to me! It works really good!