Image {EBImage}R Documentation

Image creation, copying and assertion

Description

Functions to create, copy and assert images.

Usage

  Image(data=array(0,c(0,0,1)), dim=base::dim(data), colormode, ...)

  is.Image(x)
  stopIfNotImage(x)

  ## S4 methods for signature 'x=Image'
  copy(x, ...)
  header(x, ...)

  ## S4 methods for signatures 'x=Image,y=Image'
  ## and 'x=list,y=missing'
  combine(x, y, ...)

  ## S4 methods for signatures 'x=Image,y=Image'
  ## and 'x=Image,y=missing'
  assert(x, y, strict=FALSE, ...)

Arguments

x, y Objects of class Image. There is also a combine method for lists of equally sized Image objects, in that case y should be missing.
data Data to fill the image, typically an array, but can be any object for which as.numeric or as.integer is defined.
dim A numeric vector of image dimensions with length of 2 or 3. If its length is 2, the third dimension is set to 1.
colormode An integer value for the image data color mode. It is recommended to use the predefined symbols TrueColor or Grayscale.
strict A logical scalar. If TRUE, the size of all three dimensions of two images will be compared, if FALSE, the function will compare only the first two dimensions (i.e. stacks can have different size in z-direction, but x- and y-size should be the same).
... With Image, further arguments to new; with combine, further images to be combined.

Details

Image
This is a wrapper around new, for convenience.
copy
Makes an identical copy of an object of Image enforcing allocation of new memory for the image data. Note that in R, a simple assignment like a<-b does lead to copying of the data until either a or b are further modified.
combine
Acts similarly to rbind and cbind. It allows to combine images to stacks adding further images at the back of the first one. Properties of the first image in the argument x are transferred to the result. All images must be of the same size (in first two dimensions) and color mode. If applied to a list of images, it calls do.call("combine", x)
header
Acts similarly to copy, but does not copy the actual image data, only all the other slots. This function can be useful for creating new images from existing large ones preserving attributes.
is.Image
Returns TRUE if argument is a valid Image and FALSE otherwise.
assert
Compares dimensions and color modes of two images. If argument strict is FALSE images are allowed to have different number of frames.

Value

The constructors Image, copy, combine and header return a new object of Image.
assert and is.Image return a logical.
stopIfNotImage will return invisible NULL if its argument is of Image and an error message otherwise.

Author(s)

Oleg Sklyar, osklyar@ebi.ac.uk, 2005-2007

See Also

Image, IndexedImage, readImage

Examples

  i1 = Image()
  sx = exp(24i*pi*seq(-1, 1, length=300)^2)
  i2 = Image(outer(Im(sx), Re(sx)))
  if (interactive()) display(normalize(i2))
  i3 <- copy(i2)
  is.Image(i2)
  
  ## see 'stackObjects' for example on combine
[Package EBImage version 2.4.0 Index]