function A2 = image_blowup ( A1, f )

  [ m, n, o ] = size ( A1 );

  A2 = uint8 ( zeros ( f*m, f*n, o ) );

  for i = 1 : m
    ilo = ( i - 1 ) * f + 1;
    ihi = i * f;
    for j = 1 : n
      jlo = ( j - 1 ) * f + 1;
      jhi = j * f;
      for k = 1 : o
        A2(ilo:ihi,jlo:jhi,k) = A1(i,j,k);
      end
    end
  end

  return
end
