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 starting and ending time index of local minimum
maxindex matrix of time index at which local maxima are attained. Each row specifies starting and ending time index of local maximum.
nextreme the number of extrema
cross matrix of time index of zero-crossings. Each row specifies 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 1.0.0 Index]