If I understood you correctly, what you want to try is set the "span"
argument in loess() to something fairly small (e.g., 0.1 or 0.05). The
default (0.75) is probably too large for smoothing images.
I'm not sure what you're expecting to see in your simulated example. You
simulated pure noise, so you should see (nearly) nothing after the smooth.
Andy
-----Original Message-----
From: Catalina Mesina [mailto:cmesina@cs.vu.nl]
Sent: Monday, November 25, 2002 10:54 AM
To: S-news list
Subject: [S] Gaussian smoothing
Dear all,
I have tried a 3D smoothing of my data, using "loess", or smooth but I did
not get the right smoothed image.
Suppose that my data is a matrix "myim" 50x50 and at each point (x,y) in
the grid I have an intensity value.
myim<-matrix(rnorm(2500),50,50)
x<-seq(1,50,1)
y<-seq(1,50,1)
grid<-expand.grid(x,y)
myd<-data.frame(grid[,1],grid[,2],as.vector(myim))
sm.myd<-fitted(loess(myd$X3~myd$X1*myd$X2,data=myd))
image(matrix(myd$X3,50,50))
Then what I would like to have is a gaussian smoothed image (matrix) of
myim.
I will appreciate every help answer from you.
Catalina
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