Process images

Specify scales, resize, and/or define focal objects within images.

procimg(
  image,
  resize = NULL,
  rotate = NULL,
  scaledist = NULL,
  outline = FALSE,
  reclass = NULL,
  smooth = FALSE,
  iterations = 1L,
  col = "red",
  plotnew = FALSE,
  ...
)

Arguments

image	(required) image data. Either a single image array, or a number of images stored in a list. Preferably the result of getimg().
resize	an integer specifying a percentage for resizing images, if so desired. E.g. 50 to half the size of an image, 200 to double it.
rotate	an integer specifying the angle of image rotation, in degrees. Images are rotated around the centre, and linearly interpolated.
scaledist	an integer, or numeric vector equal in length to the number of images, specifying the length of the scale in the image(s). Image(s) will then be presented, and the user asked to select either end of the scale corresponding to the input value.
outline	interactively specify the focal object in an image by clicking around its outline. The xy-coordinates of the resulting closed polygon are saved as an attribute, for use in generating a masking layer & separating animals/plants from backgrounds in further analyses. This is particularly useful when backgrounds are complex, such as in natural settings.
reclass	interactively specify an area on a colour-classified image that is to be reclassified as the numeric value provided. e.g. when reclass = 1, the user will be asked to select a polygon on the image, within which all colour-category values will be changes to 1.
smooth	should the polygon specified when outline = TRUE be smoothed using Chaikin's corner-cuting algorithm? Defaults to FALSE.
iterations	the number of smoothing iterations, when smooth = TRUE. Defaults to 1.
col	the color of the marker points and/or line, when using interactive options.
plotnew	should plots be opened in a new window? Defaults to FALSE.
...	additional graphical parameters. Also see par().

Value

an image, or list of images, for use in further pavo functions.

References

Chaikin, G. 1974. An algorithm for high speed curve generation. Computer Graphics and Image Processing 3, 346-349.

Author

Thomas E. White thomas.white026@gmail.com

Examples

if (interactive()) {
  # Single image
  papilio <- getimg(system.file("testdata/images/papilio.png", package = "pavo"))
  papilio <- procimg(papilio, scaledist = 10)

  # Assign individual scales to each image, after slightly reducing their size.
  snakes <- getimg(system.file("testdata/images/snakes", package = "pavo"))
  snakes <- procimg(snakes, scaledist = c(10, 14), resize = 90)
}