channel: Color and image color mode conversions

In aoles/EBImage: Image processing and analysis toolbox for R

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, [e-mail]

See Also

colorMode

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')

aoles/EBImage documentation built on March 18, 2024, 4:44 a.m.