extrema {EMD}R Documentation

Finding Local Extrema and Zero-crossings

Description

This function indentifies extrema and zero-crossings.

Usage

extrema(y, ndata = length(y), ndatam1 = ndata - 1)

Arguments

y input signal
ndata the number of observation
ndatam1 the number of observation - 1

Details

This function indentifies extrema and zero-crossings.

Value

minindex matrix of time index at which local minima are attained. Each row specifies a starting and ending time index of a local minimum
maxindex matrix of time index at which local maxima are attained. Each row specifies a starting and ending time index of a local maximum.
nextreme the number of extrema
cross matrix of time index of zero-crossings. Each row specifies a starting and ending time index of zero-crossings.
ncross the number of zero-crossings

See Also

extrema2dC, extractimf, emd.

Examples

y <- c(0, 1, 2, 1, -1, 1:4, 5, 6, 0, -4, -6, -5:5, -2:2)
#y <- c(0, 0, 0, 1, -1, 1:4, 4, 4, 0, 0, 0, -5:5, -2:2, 2, 2)
#y <- c(0, 0, 0, 1, -1, 1:4, 4, 4, 0, 0, 0, -5:5, -2:2, 0, 0)

plot(y, type = "b"); abline(h = 0)
extrema(y)

[Package EMD version 1.2.0 Index]