How to connect points in a binary image in matlab

Question

I have a binary image with several points as below:

How can I make a c

Answer 1

You can use roipoly to create a mask defined by the points.
Given a binary mask you can use bwmorph(BW,'remove'); to get the boundary and you are done.

The only problem is determining the order of the points, different order defines different mask. This one you'll have to figure for yourself.

Example of ambiguity in ordering the points: