warbleR (version 1.1.28)

image_to_wave: Convert images into wave objects

Description

image_to_wave converts images in 'png' format into wave objects using the inverse Fourier transformation

Usage

image_to_wave(file, duration = 1, samp.rate = 44.1, 
bit.depth = 16, flim = c(0, samp.rate / 2), plot = TRUE)

Value

A single wave object.

Arguments

file

Character with the name of image file to be converted. File must be in 'png' format.

duration

duration of the output wave object (in s).

samp.rate

Numeric vector of length 1 indicating the sampling rate of the output wave object (in kHz). Default is 44.1.

bit.depth

Numeric vector of length 1 with the dynamic interval (i.e. bit depth) for output files. Default is 16.

flim

Numeric vector of length 2 indicating the highest and lowest frequency limits (kHz) in which the image would be located. Default is c(0, samp.rate / 2).

plot

Logical argument to control if image is plotted after being imported into R.

Author

Marcelo Araya-Salas ()

Details

This function converts images in 'png' format into wave objects using the inverse Fourier transformation.

References

Araya-Salas, M., & Smith-Vidaurre, G. (2017). warbleR: An R package to streamline analysis of animal acoustic signals. Methods in Ecology and Evolution, 8(2), 184-191.

Examples

# \donttest{ 
 ### create image with text to use in the spectrogram
 # remove margins of plot
 par(mar = rep(0, 4))
 
 # empty plot
 plot(0, type='n',axes = FALSE, ann = FALSE, xlim = c(0, 1), ylim = c(0, 1))
 
 # text to include
 text <- " warbleR "
 
 # add text
 text(x = 0.5, y = 0.5, labels = text, cex = 11, font = 1)
 
 # save image in temporary directory
 dev2bitmap(file.path(tempdir(), "temp-img.png"), type = "pngmono", res = 30)
 
 # read it 
  wv <- image_to_wave(file = file.path(tempdir(), "temp-img.png"), plot = TRUE, flim = c(1, 12))

 # output wave object
 # wv
  
 ## plot it   
 # reset margins
 par(mar = c(5, 4, 4, 2) + 0.1)
 
 # plot spectrogram
 # spectro(wave = wv, scale = FALSE, collevels = seq(-30, 0, 5),
 # palette = reverse.terrain.colors, ovlp = 90, grid = FALSE, flim = c(2, 11))
# }