[Sidefx-houdini-list] Surface from image stack

Michael K. O'Brien mobrien at pixar.com
Thu Feb 11 16:34:52 EST 2010


Hola~

>-- On Thu, Feb 11, 2010 at 04:29:58PM -0500, Jerry wrote:
> Check the second tab on the trace SOP.

I tried that, but without any luck. I'll give it another go.

My sample image is 16x16, all black, white horiz line in the middle. I end up
with with a closed curve that encircles all of the pixels.

I ended up writing a medial axis node, which is really slow, but seems to be a
bit closer to what I would expect.

MO

> 
> > Hola~
> >
> >> -- On Thu, Feb 11, 2010 at 03:19:05PM -0500, Mark Elendt wrote:
> >> On Thursday Feb 11 at 14:46, Mark Bolstad wrote:
> >> > I have a stack of black and white images that consist of a set of
> >> > disconnected circle like shapes. First, how do you extract the  
> >> boundary
> >> > curve(s) and pass them to a SOP?
> >> >
> >> > Second, given a set of these extracted curves, I need to join them  
> >> into a
> >> > surface (assume some fixed offset between the curves). The problem is  
> >> that
> >> > in some cases I'll have two curves on one level and 1 curve on the  
> >> next
> >> > level (the actual data is bifurcating somewhere in between the  
> >> levels).
> >> >
> >> > The application is reconstructing neurons from a set of electron  
> >> microscopy
> >> > images.
> >> >
> >> > Any help is appreciated.
> >>
> >> Could you make a volume (even an i3d file)?
> >> The ISO SOP with an inside/out expression?
> >>
> >> If the topology changes (i.e. you have two circles blending to one),
> >> that could be problematic.
> >>
> >> If you are guaranteed to have only one circle, then use the trace SOP
> >> and poly loft (or poly spline and skin).
> >
> > Is there a way to get a true curve out of trace? Trace wants to surround  
> > each
> > pixel with a poly face, as opposed to generating a curve that connects  
> > the
> > pixels above the threshold, right?
> >
> > MO
> >
> >>
> >> --
> >> Mark Elendt
> >> _______________________________________________
> >> Sidefx-houdini-list mailing list
> >> Sidefx-houdini-list at sidefx.com
> >> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >
> 
> 
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-- 
Michael O'Brien                                                         Tools
Pixar                                                       mobrien at pixar.com

Censorship is the mother of metaphor.
                            -Jorges Luis Borges



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