Both functions create a circularly symmetric Gaussian mask of sigma. The size
of the mask is determined by the variable min_amplitude; if for instance the
value .1 is entered this means that the produced mask is clipped at values
less than 10 percent of the maximum amplitude.
The mask can be directly used with the vasari convolution
programs, the default offset set is 0.
The program uses the following equation:
H(r) = exp( -(r * r) / (2 * sigma * sigma) ).
The generated mask has odd size and its maximum value is normalised to
either 100 (gauss_imask) or to 1.0 (gauss_dmask).
creates a DOUBLEMASK laplacian of Gaussian mask with maximum value normalised
creates a INTMASK laplacian of Gaussian mask with maximum value normalised