Origami で PDF に埋めこまれている画像を抽出する ref: http://qiita.com/items/768497d84e6bf8594d6b

extract_images.rb

# coding: utf-8                                                                                                                           
require 'origami'                                                                                                                         

include Origami                                                                                                                           

pdf = PDF.read(ARGV[0])                                                                                                                   

images = pdf.root_objects.find_all {|obj| obj.is_a?(Graphics::ImageXObject)}                                                              

images.each do |stream|                                                                                                                   
  ext, image_data = stream.to_image_file                                                                                                  
  image_file = "image_#{stream.reference.refno}.#{ext}"                                                                                   
  File.open(image_file, "wb") do |f|                                                                                                      
   f.write(image_data)                                                                                                                    
  end                                                                                                                                     
end           

file1.txt

$ ruby extract_images.rb PDFファイル名