Thread Subject: Find the outter boundary of a all connected point set.

I just tried Convex Hull but it gives the one different than what I want. I want all the points in the boundary edges are the points belongs to the all connected point set.

Thanks

superZZ

"z " <zlff@sohu.com> wrote in message
news:h6dsi9$6mn$1@fred.mathworks.com...
>I just tried Convex Hull but it gives the one different than what I want. I
>want all the points in the boundary edges are the points belongs to the all
>connected point set.

So only pass the all connected point set into the convex hull routine rather
than passing in all the points.

--
Steve Lord
slord@mathworks.com

Hello, z:
I am not completely shure about what you really want, but it sounds like looking to alpha shapes might help. Check (for example) at http://cgm.cs.mcgill.ca/~godfried/teaching/projects97/belair/alpha.html
If I am not wrong, there is a contribution in this topic to the FEX (by us?)
Regards
Carlos

"z " <zlff@sohu.com> wrote in message <h6dsi9$6mn$1@fred.mathworks.com>...
> I just tried Convex Hull but it gives the one different than what I want. I want all the points in the boundary edges are the points belongs to the all connected point set.


You might be looking for bwboundaries(), assuming you have the Image Processing Toolbox