EBImage: channel – R documentation

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channel

Color and image color mode conversions

Description

channel handles color space conversions between image modes. rgbImage combines Grayscale images into a Color one. toRGB is a wrapper function for convenient grayscale to RGB color space conversion; the call toRGB(x) returns the result of channel(x, 'rgb').

Usage

channel(x, mode)
rgbImage(red, green, blue)
toRGB(x)

Arguments

`x`	An `Image` object or an array.
`mode`	A character value specifying the target mode for conversion. See Details.
`red, green, blue`	`Image` objects in `Grayscale` color mode or arrays of the same dimension. If missing, a black image will be used.

Details

Conversion modes:

rgb: Converts a Grayscale image or an array into a Color image, replicating RGB channels.
gray, grey: Converts a Color image into a Grayscale image, using uniform 1/3 RGB weights.
luminance: Luminance-preserving Color to Grayscale conversion using CIE 1931 luminance weights: 0.2126 * R + 0.7152 * G + 0.0722 * B.
red, green, blue: Extracts the red, green or blue channel from a Color image. Returns a Grayscale image.
asred, asgreen, asblue: Converts a Grayscale image or an array into a Color image of the specified hue.

NOTE: channel changes the pixel intensities, unlike colorMode which just changes the way that EBImage renders an image.

Value

An Image object or an array.

Author(s)

Oleg Sklyar, osklyar@ebi.ac.uk

Examples

x = readImage(system.file("images", "shapes.png", package="EBImage"))
 display(x)
 y = channel(x, 'asgreen')
 display(y)

 ## rgbImage
 x = readImage(system.file('images', 'nuclei.tif', package='EBImage'))
 y = readImage(system.file('images', 'cells.tif', package='EBImage'))
 display(x, title='Cell nuclei')
 display(y, title='Cell bodies')

 cells = rgbImage(green=1.5*y, blue=x)
 display(cells, title='Cells')

EBImage

Image processing and analysis toolbox for R

v4.32.0

LGPL

Authors

Andrzej Oleś, Gregoire Pau, Mike Smith, Oleg Sklyar, Wolfgang Huber, with contributions from Joseph Barry and Philip A. Marais

Initial release