Hi, my name is Ellen. I want to ask you about R Code.
I got a code for extracting a pixel value, but I can't compile it.. 
It is said "Error in is.data.frame(x) : object 'lena' not found"

Here is the original full code:

library(pixmap)
lena <- read.pnm("oldlennablur.pgm")
write.table(lena@grey,"mylenna", quote=FALSE, row.names = FALSE, col.names= FALSE)
plot(pixmapGrey(as.matrix(read.table("mylenn"))))

do you know why i got the error? i have change the "oldlennablur.pgm" with the one i have and also with the specified path on my computer..|
And would you like give me an explanation about "read.pnm". I need to know what result will i get using this syntax.
Does this syntax give us a 256x256 matrix if we input the 256x256 pixels image?
I will use the data for my project, so I need to know how and what the data i would get..
Thank you very much.. 
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