pnm {e1071}R Documentation

Portable Anymap Images

Description

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.

Usage

read.pnm(file)
plot(pnmobj, xlab="", ylab="", axes=FALSE, ...)
write.pgm(pnmobj, file="Rimage.pgm", forceplain=FALSE)
channel.pnm(pnmobj, chan = "red")

Arguments

pnmobj an object of class pnm
file name of the pnm file
forceplain If TRUE, an ASCII pgm file is written. Default is to write a binary (raw) pgm file.
chan Channel to extract (one of "red", "green" and "blue").

Value

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").

Author(s)

Friedrich Leisch

See Also

image