[iceman (Mike)]

Nice work Andy..

That threshhold parameter is needed if the image is inherintly grainy from high gain (in poor transparency).

The command line I use for ppmcentre (in a script called "image_ppm_script.sh" is:

#!/bin/sh

image_dir=$1

./ppmcentre -width=400 -height=400 -cutx=400 -cuty=400 -overwrite -inputfilter -qestimator -renumber $image_dir

I run mine through a unix emulator "cygwin" on Windows.

So if I've got several bmp directories, eg:
images/jup1bmp
images/jup2bmp
images/jup3bmp

I run the command:

for i in `ls -d images/jup*bmp`
do
./image_ppm_script.sh $i
done;

That runs the ppmcentre command through all bmp directories one after the other. So I can kick it off before I go to bed and it's done when I wake up in the morning