Rank: 274 based on 370 downloads (last 30 days) and 3 files submitted
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Nathanael Yoder

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ATA Engineering
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Files Posted by Nathanael View all
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02 Dec 2013 Screenshot PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder signal processing, maxima, minima, peaks, valleys, troughs 328 38
  • 4.90323
4.9 | 35 ratings
13 Nov 2009 Screenshot PaddedHilbert Computes the Hilbert transform of a vector after it has been padded to ameliorate end effects. Author: Nathanael Yoder hilbert transform, end effects, hilbert envelope 19 0
06 Oct 2009 Screenshot PadSignal Pads a signal with portions of the signal itself to decrease end effects. Author: Nathanael Yoder end effects, hilbert transform, wavelet transform, hht, emd, hvt 23 0
Comments and Ratings by Nathanael View all
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23 Aug 2013 PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder

@Jakob Are you sure you are calling this function? Line 98 in this peakfinder is: dx0 = diff(x0); % Find derivative.

Also the function unfortunately does not accept cell inputs

14 Jun 2011 PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder

Thanks for catching that Tim. You were exactly right, the redundancy is an artifact from when I preallocated the matrix for speed. However, I essentially replaced this statement with the leftMin variable which is why you got the same results. The end effect is that the second part of that conditional can simply be eliminated.

Thanks again for your help and an updated version with the addition of a user defined threshold should be available shortly.

01 Dec 2009 layerplot A plot function much more powerful than plotyy Author: Zhipeng Gao

Has issues with resizing

01 Dec 2009 layerplot A plot function much more powerful than plotyy Author: Zhipeng Gao

16 Dec 2008 Kernel Density Estimator Reliable and extremely fast kernel density estimator for one-dimensional data Author: Zdravko Botev

I was incorrect but there does seem to be a scale factor on the density functions

Comments and Ratings on Nathanael's Files View all
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09 Apr 2014 PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder Frank

Works (almost) good.
However it does not detect all peaks, I think there is a bug. The index in lines 186ff for finding the valley should be different from ii, e.g. jj:

jj = ii+1; % Move onto the valley
% Come down at least sel from peak
if ~foundPeak && tempMag > sel + x(jj)
foundPeak = true; % We have found a peak
leftMin = x(jj);
peakLoc(cInd) = tempLoc; % Add peak to index
peakMag(cInd) = tempMag;
cInd = cInd+1;
elseif x(jj) < leftMin % New left minima
leftMin = x(jj);
end

09 Apr 2014 PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder dong

07 Feb 2014 PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder ZOU, Liang

Great. It works fine for ecg peak detection.

07 Feb 2014 PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder ZOU, Liang

06 Feb 2014 PeakFinder Quickly finds local maxima (peaks) or minima (valleys) in a noisy signal. Author: Nathanael Yoder Trevor

Very useful, thanks! For my application I was trying to find the average of peaks from some experimental data that had some outliers, so I used trimmean() on the output of this function.

@mptorr - just do a max() on the output. e.g. [~,peakdata]=peakfinder(x0) ... max(peakdata)

@Ali - there is an option for this in peakfinder. Make the 4th input argument -1 to find minimums (type "help peakfinder" into the command window for more info)

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