Segmentation Identifiers

[kamakshidasan]

Hi,

I'm trying to segment a scalar field using the contour tree (FTM).

If I apply a 'RegionType' threshold on the segmentation, I am able to see all regions that I am interested in [1 for Maxima, 3 for Split Saddles].

Here's a screenshot from a Von Karman sheet, segmented on split saddles.

I'm interested in knowing the segmented region associated with a particular saddle/maxima.

When I try to threshold further on 'SegmentationId', they seem to be disconnected in nature. For example, look at this screenshot. You should be able to notice three different blue regions on the right. However, this same method seems to work properly when dealing with local maximas.

Is this behaviour expected? If yes, how should I about looking at regions associated with split saddles?

Cheers!

[kamakshidasan]

Also, I'm using the Github version of TTK.

[julien-tierny]

hi there, contour tree driven segmentations are vertex based (if they were to segment through faces, they'd be *much* more expenseive to compute). if your input mesh is not dense enough, pre-images of arcs of the tree may be sparsely sampled by the vertices and hence, appear disconnected while they are not. so in short, yes, this is the expected behavior. I'm going to close this issue then. I'd recommend to continue this discussion on the ttk-users@googlegroups.com mailing list, but in short, refining your input mesh should be a sufficient workaround. cheers, -- Dr Julien Tierny CNRS Researcher Sorbonne Universite http://lip6.fr/Julien.Tierny

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On Tuesday, August 7, 2018 4:17:39 PM CEST Kamakshidasan wrote: Also, I'm using the Github version of TTK.

[kamakshidasan]

@julien-tierny, Could you please forward this to ttk-users? I can't seem to forward this thread to my e-mail with the above screenshots.

[julien-tierny]

already did. thanks. -- Dr Julien Tierny CNRS Researcher Sorbonne Universite http://lip6.fr/Julien.Tierny

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On Wednesday, August 8, 2018 4:05:17 PM CEST Kamakshidasan wrote: @julien-tierny, Could you please forward this to ttk-users? I can't seem to forward this thread to my e-mail with the above screenshots.