How do i transform/convert a structuring element to an binary image in Matlab?

How do i transform/convert a structuring element to an binary image in Matlab? For example, say i need to convert a square structuring element

   se = strel('square',7)

Kindly help me in this matter, i really need a method. Thank you

Answer 1

[Jeff E]

>> se = strel('square',7);

>> nhood = getnhood(se);

>> whos('se' ,'nhood')

Name       Size            Bytes  Class      Attributes

nhood      7x7                49  logical              
se         1x1               112  strel

Answer 2

[Roro]

Jeff, how do i make my structuring element to look like the attached image? can you help me with the sintax please ? the se in this case is a disk. I've used the following code lines:

    % clear
se=strel('disk',10)
nh=getnhood(se)
p=padarray(nh, [10 10], 0, 'both');
imshow(p)

[Jeff E]

I'm not sure I can explain the syntax any better than the help, but in this specific instance you need to give the radius of the disk, not the total width/height like you do with square. So, for the first graphic try 5 or 6 instead of 10.

For the second two, it looks like they used a non-default approximation to get a smoother circle. Something like this:

se = strel('disk', 10, 8);

As usual, Steve Eddins has a great blot post about how Matlab decomposes structuring elements to improve performance: http://blogs.mathworks.com/steve/2008/09/17/dilation-structuring-element-decomposition//