Wavelet Cone of Influence

The Morlet cone of influence (Torrence and Compo 1998): the largest period, in hours, at each time point below which the wavelet power is free of edge effects. Power at periods above this curve, near the start and end of the recording, is unreliable. circadian.wavelet returns this curve in its result; this helper computes it directly for plotting or masking.

Usage

wavelet.coi(timestamps, omega0 = 6, epoch_length = 60)

Arguments

timestamps

POSIXct timestamps, one per epoch.

omega0

Morlet central frequency (default 6).

epoch_length

Epoch length in seconds (default 60).

Value

Numeric vector, one per epoch, of the maximum reliable period (hours).

References

Torrence C, Compo GP (1998). “A practical guide to wavelet analysis.” Bulletin of the American Meteorological Society, 79(1), 61–78. doi:10.1175/1520-0477(1998)079<0061:APGTWA>2.0.CO;2 .

See also

circadian.wavelet

Examples

ts <- seq(as.POSIXct("2024-01-01", tz = "UTC"), by = 600, length.out = 6 * 144)
range(wavelet.coi(ts, epoch_length = 600))
#> [1] 1.217454e-06 5.247225e+01