MATLAB: To find max peak intensity

MATLABmax peak intensity

Hi,

I would need some help how to find max peak intensity (not min and not threshold) in spectra over time or freq domain (both).

Please help me with some usable answer because at the homepage I did not find somthing to use for this purpose.

Many thanks for the response in advance.

Regards.

Bandi

Best Answer

The findpeaks function (or the islocalmax function) are what I would use, although the max function is also an option for finding one peak.

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MATLAB: How can i find this minima

One approach is to use diff or gradient to calculate the approximate derivative of your data. Then ‘threshold’ the negative values of the derivative to be as large as necessary to detect the abrupt negative changes. Those will give you the points where the change is greatest. Calculating the points with the red arrows should be relatively straightforward.

The easiest way to find those using findpeaks is probably to first negate your signal (so the ‘dips’ become peaks), then use findpeaks to find the ‘peaks’ of the negated signal. Subtract as many indices as you need from those returned by findpeaks to get the points indicated by the arrows.

MATLAB: Calculate FWHM and area of multiple peak

‘... it gives 1×0 empty double row vector.’

That is most likely because the dependent variable vector (is this ‘y’ in your code?) must be the first argument to findpeaks (link).

Try this instead:

[pks,locs,widths,proms] = findpeaks(y,x);

or preferably, just return the indices of the peaks in the ‘locs’ output with:

[pks,locs,widths,proms] = findpeaks(y);

I find the indices easier to work with.

Best Answer

Related Solutions

MATLAB: How can i find this minima

MATLAB: Calculate FWHM and area of multiple peak

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