read.pnm reads a pnm file and loads the image into an
object of class pnm, which is basically a
matrix (pbm, pgm) or a 3-dimensional arry with 3 matrices for red,
green and blue. write.pgm writes an object of class pnm to a
pgm file. Generalizations for writing pbm and ppm files are yet to be
written.
plot.pnm plots a pnm object using the command
image. The only difference is that the element [1,1] of
pnmobj is plotted as the upper left corner (plain
image would plot [1,1] as the lower left corner.
channel.pnm extracts a black-and-white picture corresponding to
one of the three color channels.
read.pnm(file)
plot(pnmobj, xlab="", ylab="", axes=FALSE, ...)
write.pgm(pnmobj, file="Rimage.pgm", forceplain=FALSE)
channel.pnm(pnmobj, chan = "red")"pnm".TRUE, an ASCII pgm file is written.
Default is to write a binary (raw) pgm file."red", "green"
and "blue").read.pnm returns an object of class pnm. The maximum
value (of either grey or the red/green/blue channels) is stored as
attribute "maxval"). The type (pbm, pgm or pnm) is stored as
attribute "type").image