Learn R Programming

imager (version 0.45.8)

contours: Return contours of image/pixset

Description

This is just a light interface over contourLines. See help for contourLines for details. If the image has more than one colour channel, return a list with the contour lines in each channel. Does not work on 3D images.

Usage

contours(x, nlevels, ...)

Value

a list of contours

Arguments

x

an image or pixset

nlevels

number of contour levels. For pixsets this can only equal two.

...

extra parameters passed to contourLines

Author

Simon Barthelme

See Also

highlight

Examples

Run this code
cimg.limit.openmp()
boats.gs <- grayscale(boats)
ct <- contours(boats.gs,nlevels=3)
plot(boats.gs)
#Add contour lines
purrr::walk(ct,function(v) lines(v$x,v$y,col="red"))
#Contours of a pixel set
px <- boats.gs > .8
plot(boats.gs)
ct <- contours(px)
#Highlight pixset
purrr::walk(ct,function(v) lines(v$x,v$y,col="red"))

Run the code above in your browser using DataLab