readImage {EBImage} | R Documentation |
Functions to read and write images from/to files and URL's. The supported image formats depend on the capabilities of ImageMagick.
readImage(files, colormode) writeImage(x, files, quality = 100)
files |
A character vector of file names or URLs. If missing, an interactive file chooser is displayed. |
x |
An |
quality |
A numeric, ranging from 1 to 100. Default is 100. |
colormode |
Deprecated. |
When writing images in formats supporting lossy compression (like JPEG),
the quality can be specified used a quality
value in the
range [1,100]
. The best quality is obtained with 100.
The file format is deduced from the file name extension.
ImageMagick
is used to perform all image I/O operations. Therefore,
the package supports all the file types supported by ImageMagick
.
When reading images, files of different formats can be mixed in any sequence, including mixing single 2D images with TIFF image stacks. The result will contain a stack with all images and stacks, at the size of the first image read. Subsequent images are cropped (if larger) or filled with background (if smaller).
readImage
returns an Image
object, containing an array of
double values ranging from 0 (black) to 1 (white). Image formats have
a limited dynamic range (e.g. JPEG: 8 bit, TIFF: 16 bit) and
writeImage
may cause some loss of accuracy.
readImage
returns a new Image
object.
writeImage
returns invisible(files)
.
Oleg Sklyar, osklyar@ebi.ac.uk, 2005-2006
ImageMagick: http://www.imagemagick.org
## Reads and display images f = system.file("images", "lena-color.png", package="EBImage") x = readImage(f) if (interactive()) display(x) x = readImage(system.file("images", "nuclei.tif", package="EBImage")) if (interactive()) display(x) try({ im = readImage("http://www.google.com/intl/en/images/logo.gif") if (interactive()) display(im) }) ## Converts a TIFF file into JPEG f1 = system.file("images", "lena-color.png", package="EBImage") x1 = readImage(f1) f2 = paste(tempfile(), "jpeg", sep=".") writeImage(x1, f2) cat("Converted '", f1, "' into '", f2, "'.\n", sep='')