@conf = (
   {'step' => 8,  'blur_fwhm' => 4,  'iterations' => 20},
   {'step' => 6,  'blur_fwhm' => 3,  'iterations' => 20},
   {'step' => 4,  'blur_fwhm' => 2,  'iterations' => 10},
   {'step' => 2,  'blur_fwhm' => 1,  'iterations' => 10},
   );