save 3D matrix as gif

Function that saves a 3D matrix in a gif image file.

save_3D_matrix_as_gif
---------------------
Function that saves a 3D matrix in a gif image.

input:
filename = the desired name of the output file
e.g.: 'C:\Users\John\Desktop\animation.gif'
or 'animation.gif' (saves in current folder)
matrix = the 3D matrix, matrix(:,:,n) contains the n'th frame of the
desired gif animation
delaytime = optional argument to specify the delay time (in seconds)
of the gif file (default = 0.1 sec)
output:
/

example:
Im = zeros(100,100,20);
% create circles with decreasing radii
for ii=1:20
Im(:,:,ii) = phantom([1 1/ii 1/ii 0 0 0],100);
end
save_3D_matrix_as_gif('C:\Users\John\Desktop\name_of_gif_file.gif',Im,0.2)

author: Geert Van Eyndhoven
contact: vegeert[at]hotmail[dot]com