#!/usr/bin/perl
use warnings;
use strict;
use LWP::Simple;
use PDL;
use PDL::Graphics::PGPLOT; 

# getting a brain image from the ITK (http://itk.org) CVS website
my $img_url = "http://www.itk.org/cgi-bin/viewcvs.cgi/*checkout*/Examples/Data/BrainProtonDensitySliceBorder20.png?rev=1.2&root=Insight"; 

my $savefilename = "brain.png";

my $status = getstore($img_url,$savefilename);

print $status."\n" if is_success($status);


# reading the image and creating a copy of it
$brain = rim( “brain.png” );
$brain2 = $brain->copy;


#plotting the two images in two different windows
$dev = '/XSERVE';

$win = PDL::Graphics::PGPLOT::Window->new( { Dev => $dev } );

$win->imag( $brain );

$win2 = PDL::Graphics::PGPLOT::Window->new( { Dev => $dev } );

$win2->imag( $brain2 );


# The pixel values in the images are in the range [0, 255]
# (with zero representing black and 255 representing white).
#
# Let's change all the pixel values greater than 220 to be 
# equal to zero. This will create some black spots in the 
# image
$indx = which( $brain > 220 );

$brain2->flat->index( $indx ) .= 0;


# Let's plot the new image
$win2->imag( $brain2 );


# Now, we free up the windows so that you can close them.
$win->close();

$win2->close();