function pioneers_noise_test ( )

%*****************************************************************************80
%
%% pioneers_noise_test() adds noise to the "pioneers" image.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    03 February 2019
%
%  Author:
%
%    John Burkardt
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'pioneers_noise_test():\n' );
  fprintf ( 1, '  Add various kinds of noise to the "pioneers" image.\n' );

  g = imread ( 'pioneers.png' );

  g2 = gray_salt_and_pepper ( g, 0.05 );
  imwrite ( g2, 'pioneers_05.pgm', 'pgm' );

  g2 = gray_salt_and_pepper ( g, 0.10 );
  imwrite ( g2, 'pioneers_10.pgm', 'pgm' );

  g2 = gray_salt_and_pepper ( g, 0.20 );
  imwrite ( g2, 'pioneers_20.pgm', 'pgm' );

  g2 = gray_salt_and_pepper ( g, 0.40 );
  imwrite ( g2, 'pioneers_40.pgm', 'pgm' );

  g2 = gray_salt_and_pepper ( g, 0.60 );
  imwrite ( g2, 'pioneers_60.pgm', 'pgm' );

  g2 = gray_salt_and_pepper ( g, 0.80 );
  imwrite ( g2, 'pioneers_80.pgm', 'pgm' );

  return
end
