[Sidefx-houdini-list] Surface from image stack

Mark Bolstad the.render.dude at gmail.com
Thu Feb 11 17:47:39 EST 2010


Posted to the forum:

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=86172#86172
.

Thanks,

Mark


2010/2/11 François Duchesneau <sidefx at trinix.ca>

> You'll have to continue this thread on the forum to attach images.
>
> Mark Bolstad wrote:
> > Thanks for the ideas.
> >
> > If the list will allow me to attach images, I'll append 3 images that are
> > representative of consecutive levels. This one has a bifurcation on level
> > two.
> >
> > Mark
> >
> >
> > 2010/2/11 François Duchesneau <sidefx at trinix.ca>
> >
> >
> >> That reminds me a tool I created to mimick Blast Code. In Blast Code you
> >> could use a bad quality crack pattern found on the web with varying line
> >> thickness. The tool I created used the Trace Sop internally but had to
> >> do lots of Sop operation to make it work. However, it was very picky
> >> about the line width. I'd be curious to know what is the algorithm Blast
> >> Code uses because it looks more like something giving the center of the
> >> line only, like you want. That little improvement on the Trace Sop would
> >> be great.
> >>
> >> François
> >>
> >> Michael K. O'Brien wrote:
> >>
> >>> 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
> >>>>>>
> >>>>>>
> >>>> _______________________________________________
> >>>> Sidefx-houdini-list mailing list
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> >>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >>>>
> >>>>
> >>>
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> >>
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