[Insight-users] Re: 2D boundary tracking

[Amadeus W. M.]

On Fri, 15 Sep 2006 10:15:07 -0700, Zachary Pincus wrote:

> I wrote such a filter to fill this need in ITK several months ago. It  
> currently resides (some might say languishes), along  with many other  
> useful filters, on the InsightJournal.
> 
> Get the files at:
> http://hdl.handle.net/1926/165
> 
> It applies a classic contour-extraction method (the 2d equivalent of  
> marching cubes) to an image and gives back a set of  
> itk::PolyLineParametricPath objects. To get contours from a binary  
> image, you should set the contour value parameter to halfway between  
> the inside and outside intensity.
> 
> 
> Zach Pincus
> 
> Program in Biomedical Informatics and Department of Biochemistry
> Stanford University School of Medicine
> 
> 
> 
> On Sep 14, 2006, at 6:44 PM, Amadeus W. M. wrote:
> 
>> I have a binary image and I want to track the border of a
>> blob in the image, as an ordered sequence of consecutive points.
>> Is there any 2D boundary tracking filter in itk?
>>
>>
>>
>> _______________________________________________
>> Insight-users mailing list
>> Insight-users at itk.org
>> http://www.itk.org/mailman/listinfo/insight-users


Thanks! I implemented a naive 2D bdry tracking algorithm 
a while back, which starts at a boundary point, and keeps moving
along the boundary until it gets back at the starting point.
Yes, I'm assuming the "object" is entirely in the interior of
the image. Every time I run it on new examples I run into trouble
and discover a new bug (not really bugs, but rather situations I 
had not anticipated), which made me realize it's not as trivial
as I first thought. 

Good to have an implementation of real algorithm. You wouldn't 
happen to have a non itk implementation, would you? I'm using 
this outside itk and it's not exactly easy to merge itk code into
my own.