#!/home/software/ruby-1.8.5/bin/ruby -w
require 'RMagick'
include Magick
img = Image.read('images/Flower_Hat.jpg').first
begin
result = img.bilevel_channel(2*MaxRGB/3, RedChannel)
# Substitute the standard "Not Implemented" image
rescue NotImplementedError
result = Magick::Image.read("images/notimplemented.gif").first
result.resize!(img.columns, img.rows)
end
result.write('bilevel_channel.jpg')
exit