read.image {EBImage} | R Documentation

## Image I/O

### Description

Functions to choose, read and write images from/to files and URL's. Supported image formats are determined by the ImageMagick installation.

### Usage

      choose.image()
      read.image(files, colormode = Grayscale, ...)
      write.image(x, files, quality, ...)

### Arguments

`x` | An object of `Image-class`.
`files` | A character vector of files/URL's to read from or to write to.
`colormode` | An integer value for the color mode of images after they are read. By default all images will be converted to Grayscale on read.
`quality` | A numeric in the range `[1,100]` defining the quality of non-lossless compression, such as JPEG, when saving images. Higher values correspond to better quality.
`...` | Reserved for future use.

### Details

If `files` is missing when writing images, `fileName(x)` method will be used to select a single file to write to. Otherwise, the length of this vector must be equal either 1 or the number of 2D images in the stack.

The file format is deduced from the file name extension(s), there is neither a need nor a way to specify the format explicitly.

`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 consequence, including mixing single 2D images with TIFF image stacks. The result will contain a stack of all images and stacks cropped (filled with background if images are smaller) at the size of the first image read.

`choose.image` is an interactive function that does not return to R until either Ok or Cancel button is pressed in the GUI dialog. It uses `GTK+2` File Open Dialog to select images. Multiple images can be selected and loaded at once. By default this functions reads images as `TrueColor`. This function will produce an error message if the package was compiled without `GTK+` support.

### Value

For `read.image` a new instance of `Image-class`.
For `choose.image` a new instance of `Image-class` in the `TrueColor` mode.
For `write.image` an invisible `NULL`.

### Author(s)

Copyright (c) 2005-2006 Oleg Sklyar : osklyar@ebi.ac.uk

### References

ImageMagick: http://www.imagemagick.org.

### See Also

`Image-class, Image, channel`

### Examples

      if ( interactive() ) {
        ddir <- paste( system.file(package="EBImage"), "images", sep="/" )
        a <- read.image( paste(ddir, c("A04w0.jpg", "A04w1.jpg"), sep="/") )
        url <- c("http://www.google.com/intl/en/images/logo.gif")
        im <- read.image (url, TrueColor)
        ## Not run: write.image (im, "googlelogo.tif")
        ## Not run: im1 <- channel ( choose.image(), "gray")
      }

[Package EBImage version 2.0.1 Index]