Convert the scalogram matrix to a data frame — as.data.frame.fcwtr

Internally, the scalogram resulting from fcwt() is represented by a numeric matrix(). This method converts this matrix into a three-columned data.frame() (two columns to represent the matrix indices, and one column for the corresponding value). Note that this conversion has a significant run time cost.

Usage

# S3 method for class 'fcwtr_scalogram'
as.data.frame(x, ...)

Arguments

x: An "fcwtr_scalogram" object resulting from fcwt().
...: Additional arguments are ignored.

Value

A data.frame() object representing the scalogram data with four columns:

time_index: An integer index uniquely identifying time slices.
time: The time difference to the first time slice in physical units. The time unit is the inverse of the frequency unit chosen by the user for the sample_freq argument of fcwt().
freq: The frequency in the same units as the sample_freq argument of fcwt().
value: The fCWT result for the particular time-frequency combination.

Examples

fcwt(
  sin((1:5000) * 2 * pi * 440 / 44100),
  x_sample_freq = u(44100, "Hz"),
  n_freqs = 10
) |>
  as.data.frame() |>
  head()
#>   time_index             time       freq        value
#> 1          0 0.0000000000 [s] 22050 [Hz]           NA
#> 2          1 0.0003799356 [s] 22050 [Hz] 1.229610e-05
#> 3          2 0.0007598712 [s] 22050 [Hz] 7.816250e-06
#> 4          3 0.0011398069 [s] 22050 [Hz] 6.032826e-06
#> 5          4 0.0015197425 [s] 22050 [Hz] 5.094111e-06
#> 6          5 0.0018996781 [s] 22050 [Hz] 4.511332e-06