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Highlights from
Localpeaks

  • functionTemplate(input_args)
    FUNCTIONTEMPLATE Summary of this function goes on this H1 line
  • iosr.acoustics.irStats(fi...
    IRSTATS Calculate RT, DRR, Cte, and EDT for impulse response file
  • iosr.acoustics.rtEst(abs_...
    RTEST Estimate reverberation time based on room size and absorption
  • iosr.auditory.azimuth2itd...
    AZIMUTH2ITD Convert azimuth in degrees to ITD
  • iosr.auditory.binSearch(S...
    Conduct a binary search
  • iosr.auditory.calcIld(L,R...
    CALCILD Calculate normalised interaural level difference
  • iosr.auditory.chXcorr(hc_...
    CHXCORR Calculate cross-correlograms with a wide range of options.
  • iosr.auditory.chXcorr2(hc...
    CHXCORR2 Calculate cross-correlograms with a range of options.
  • iosr.auditory.createWindo...
    Create a Hann or exp. window with specified onsets/offsets
  • iosr.auditory.dupWeight(f)
    DUP_WEIGHT Calculate duplex weighting coefficients for ITD and ILD
  • iosr.auditory.erbRate2hz(x)
    ERBRATE2HZ Convert ERB rate to Hz.
  • iosr.auditory.freqMulti(f)
    FREQMULTI Calculate frequency coefficient for ITD-azimuth warping
  • iosr.auditory.gammatoneFa...
    GAMMATONEFAST Produce an array of responses from gammatone filters via FFT
  • iosr.auditory.hz2erbRate(x)
    HZ2ERBRATE Convert Hz to ERB rate
  • iosr.auditory.instItd(l,r...
    INSTITD Calculate instantaneous ITD
  • iosr.auditory.iso226(phon...
    ISO226 ISO 226:2003 Normal equal-loudness-level contours
  • iosr.auditory.itd2azimuth...
    ITD2AZIMUTH Convert ITD to azimuth
  • iosr.auditory.lindemannIn...
    LINDEMANNINH Signal pre-processing for Lindemann's cross-correlation
  • iosr.auditory.loudWeight(...
    LOUDWEIGHT Calculate loudness weighting coefficients based on ISO 226
  • iosr.auditory.makeErbCFs(...
    MAKEERBCFS Make a series of center frequencies equally spaced in ERB-rate.
  • iosr.auditory.meddisHairC...
    Calculate Ray Meddis' hair cell model for a number of channels.
  • iosr.auditory.perceptualC...
    PERCEPTUALCENTROID Perceptual spectral centroid
  • iosr.auditory.xcorrLindem...
    XCORRLINDEMANN Cross-correlation based on Lindemann's precedence model
  • iosr.bss.applyIdealMasks(...
    APPLYIDEALMASKS Calculate and apply ideal masks via STFT
  • iosr.bss.applyMask(s,m,nf...
    APPLYMASK Apply a time-frequency mask to an STFT
  • iosr.bss.calcImr(m,im)
    CALCIMR Calculates the Ideal Mask Ratio (IMR)
  • iosr.bss.calcSnr(output,t...
    CALCSNR Calculate the separation SNR
  • iosr.bss.cfs2fcs(cfs,fs)
    CFS2FCS Calculate gammatone crossover frequencies.
  • iosr.bss.generateMixtures...
    GENERATEMIXTURES Generate arrays of mixtures from targets and interferers.
  • iosr.bss.getFullMask(m,fr...
    GETFULLMASK Convert frame rate mask to a sample-by-sample mask
  • iosr.bss.idealMasks(st,si...
    IDEALMASKS Calculate ideal time-frequency masks from STFTs
  • iosr.bss.resynthesise(x,f...
    RESYNTHESISE Resynthesise a target from a time-frequency mask
  • iosr.dsp.autocorr(x,Q,dim)
    AUTOCORR Perform autocorrelation via FFT
  • iosr.dsp.convFft(a,b,shape)
    CONVFFT Convolve two vectors using FFT multiplication
  • iosr.dsp.istft(s,nfft,hop...
    ISTFT Calculate the Inverse Short-Time Fourier Transform
  • iosr.dsp.lapwin(L,b)
    LAPWIN Laplace window.
  • iosr.dsp.localpeaks(x,mode)
    LOCALPEAKS Find local peaks and troughs in a vector
  • iosr.dsp.ltas(x,fs,varargin)
    LTAS calculate the long-term average spectrum of a signal
  • iosr.dsp.matchEQ(x,fs,mag...
    MATCHEQ Match the LTAS of a signal to an arbitrary spectral magnitude
  • iosr.dsp.rms(x,dim)
    RMS Calculate the rms of a vector or matrix
  • iosr.dsp.sincFilter(x,Wn,...
    SINCFILTER Apply a near-ideal low-pass or band-pass brickwall filter
  • iosr.dsp.smoothSpectrum(X...
    SMOOTHSPECTRUM Apply 1/N-octave smoothing to a frequency spectrum
  • iosr.dsp.stft(x,nfft,hop,fs)
    STFT Calculate the short-time Fourier transform of a signal
  • iosr.dsp.vsmooth(x,frame,...
    VSMOOTH Smooth a vector using mathematical functions
  • iosr.figures.chMap(M)
    CHMAP Create a monochrome-compatible colour map
  • iosr.figures.cmrMap(M)
    CMRMAP Create a monochrome-compatible colour map
  • iosr.figures.multiwaveplo...
    MULTIWAVEPLOT Stacked line plots from a matrix or vectors
  • iosr.figures.subfigrid(nr...
    SUBFIGRID Create axis positions for subfigures
  • iosr.general.cell2csv(C,f...
    CELL2CSV Output a cell array to a CSV file
  • iosr.general.checkMexComp...
    CHECKMEXCOMPILED Check if mex file is compiled for system
  • iosr.general.getContents(...
    GETCONTENTS Get the contents of a specified directory
  • iosr.general.updateConten...
    UPDATECONTENTS Create a Contents.m file including subdirectories
  • iosr.general.urn(varargin)
    URN Generate random number sequence without duplicates
  • iosr.install
    INSTALL Set search paths, and download and install dependencies.
  • iosr.statistics.getRmse(X...
    GETRMSE Calculate the root-mean-square error between input data
  • iosr.statistics.laprnd(va...
    LAPRND Pseudorandom numbers drawn from the Laplace distribution
  • iosr.statistics.qqPlot(va...
    QQPLOT Quantile-quantile plot with patch option
  • iosr.statistics.quantile(...
    QUANTILE Quantiles of a sample via various methods.
  • iosr.statistics.tab2box(X...
    TAB2BOX Prepare tabular data for boxPlot function
  • iosr.statistics.trirnd(va...
    TRIRND Pseudorandom numbers drawn from the triangular distribution
  • iosr.svn.buildSvnProfile(...
    BUILDSVNPROFILE Read data from files tagged with SVN keywords
  • iosr.svn.headRev(folders,...
    HEADREV Retrieve the head revision for specified files
  • iosr.svn.readSvnKeyword(f...
    READSVNKEYWORD Read data from a file tagged with an SVN keyword
  • classTemplate
    CLASSTEMPLATE Summary of this class goes on this H1 line
  • iosr.bss.mixture
    MIXTURE Class of binaural sound source separation mixture.
  • iosr.bss.source
    SOURCE Class of sound source separation source.
  • iosr.dsp.audio
    AUDIO Abstract superclass providing audio-related properties and methods.
  • iosr.statistics.boxPlot
    BOXPLOT Draw a box plot
  • Contents.m
    +IOSR
  • example.m
    determine STFT parameters
  • View all files

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4.83333
4.8 | 6 ratings Rate this file 19 Downloads (last 30 days) File Size: 611 KB File ID: #25355 Version: 1.7

Localpeaks

by

 

18 Sep 2009 (Updated )

Find local peaks or troughs in a vector

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File Information
Description

NOTE: this function is now available from the IoSR Matlab Toolbox as iosr.dsp.localpeaks.
-------------------------
LOCALPEAKS Find local peaks and troughs in a vector
  
SYNTAX
  
    peaks = localpeaks(X)
    peaks = localpeaks(X,MODE)
  
  
DESCRIPTION
  
peaks = localpeaks(X) locates the local peaks in vector X.
  
peaks = localpeaks(X,MODE) locates local features specified by MODE. MODE can be set to 'peaks' (default), 'troughs' in order to identify local troughs or 'both' in order to identify both local peaks and troughs.

Acknowledgements

This file inspired Peaks Picking.

MATLAB release MATLAB 7.4 (R2007a)
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Comments and Ratings (9)
06 Sep 2013 zhiyang  
21 Jun 2012 Wilson

Wilson (view profile)

 
19 Apr 2011 Jeremy

Jeremy (view profile)

I don't like not having a blank line after the last line of code. Just kidding, awesome job on this function. Very simple, intuitive, and fast.

01 Jun 2010 Christopher Hummersone

Thanks for your comment Christos, I hadn't noticed this behaviour (I had been using it with long signals). I have fixed the function to address your first remark, and the code will now correctly identify peaks and troughs in a vector like [0 5 -5 5 0] with the 'both' option. I have not addressed your second comment since, as you alluded to, this is a plateaux and not a true peak.

Comment only
01 Jun 2010 Christos Saragiotis

Very good and an excellent example of terse programming.

I have two remarks though:
1. when selecting the 'both' option some peaks or troughs may be lost. E.g consider the vector [0, 5 -5, 5, 0]. Clearly -5 is a trough but localpeaks will not pick it.
2. if we consider again the vector [ 0 5 5 5 0], localpeaks will pick the first and last 5 as a peak but not the second one. I'm not sure if this was intentional but the way I see it it should either pick all of them or none.

25 May 2010 michael scheinfeild  
28 Apr 2010 Christopher Hummersone

or rather,

y = zeros(size(x)); peaks = localpeaks(x);
y(peaks) = x(peaks);

Comment only
01 Apr 2010 Christopher Hummersone

I didn't really see the point, if you want the value you can just do for example:
y = x(localpeaks(x));

Comment only
25 Sep 2009 Herve

Herve (view profile)

Brillant !
You could have added an extra output which gives the values of the local peaks or throughs.

Updates
27 Apr 2010 1.1

added the 'both' option, updated help, acknowledged other submission

29 Apr 2010 1.2

Fixed a silly mistake, removed index output to bring the function more in line with MATLAB conventions (find(localpeaks(x)) would do the same), added an error trap

27 May 2010 1.6

Updated description

01 Jun 2010 1.7

Updated to address Christos Saragiotis' comment

11 Aug 2016 1.7

Migrated to GitHub.

11 Aug 2016 1.7

Corrected description.

18 Sep 2016 1.7

Corrected title.

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