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Great! This is correct.<br>
<br>
Yes they can be partially outside the mask because I neither know
the sizes and locations of the regions I want to keep nor the sizes
and locations of the regions I want to discard for both input image
and mask image (the mask changes dynamically)<br>
<br>
Ok so in later progress I could use the mask as the second input
(the stencil) and this removes the regions?<br>
<br>
<br>
<br>
My current code lets me get the regions I want to discard by storing
the polydata output of vtkPolyDataConnectivityFilter and then
iterate over the cells and their points<br>
<br>
for (int i = 0; i < filter->GetNumberOfExtractedRegions();
i++)<br>
{<br>
vtkSmartPointer<vtkPolyData> extractRegionData =
vtkSmartPointer<vtkPolyData>::New(); //fast<br>
extractFilter->InitializeSpecifiedRegionList(); //fast<br>
extractFilter->AddSpecifiedRegion(i); //fast<br>
extractFilter->Modified(); //fast<br>
extractFilter->Update(); //very long<br>
extractRegionData->DeepCopy(extractFilter->GetOutput());
//fast<br>
regionList.push_back(extractRegionData); //fast<br>
}<br>
for (int i = 0; i < filter->GetNumberOfExtractedRegions();
i++)<br>
{<br>
// some other operations<br>
}<br>
<br>
The update() process takes a very long time. As an example, if I
have about 200 regions, this would take about 10 minutes. All other
following operations on the data and/or a
vtkPolyDataConnectivityFilter do not take so long.<br>
<br>
- Imre<br>
<br>
<div class="moz-cite-prefix">Am 02.01.2016 um 20:48 schrieb David
Gobbi:<br>
</div>
<blockquote
cite="mid:CANwS1=EHUscGsPagE7_FLRwtz=g6Csq5Cfw9WWVHUcgwg5yXJw@mail.gmail.com"
type="cite">
<div dir="ltr">Thanks, that helps. Here is my understanding so
far:
<div><br>
</div>
<div>1) The mask is, originally, a polydata contour.</div>
<div>2) The mask indicates the regions you do not want.</div>
<div>3) The mask will be converted into a binary image before
use.</div>
<div><br>
</div>
<div>What I still need to know is:</div>
<div><br>
</div>
<div>3) Will some regions be partially within and partially
outside the mask? Or will they always be entirely within or
entirely outside?</div>
<div><br>
</div>
<div>The vtkImageConnectivityFilter takes two inputs: the first
input is just an image (of course) and the second input (which
is optional) is an image stencil (essentially a binary
image). There is a filter called vtkPolyDataToImageStencil
which can be used create this second input from a vtkPolyData
object.</div>
<div><br>
</div>
<div> - David</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, Jan 2, 2016 at 12:32 PM, Imre
Goretzki <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:goretzki.imre@gmail.com" target="_blank">goretzki.imre@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> I've drawn another
image you could look at. The left image is the input data
from which I would like to extract the regions. Here every
region I would like to keep is painted green. The other
two regions, that are painted red, have points that are
located inside a region in the binary mask.<br>
<br>
<br>
For all points <i>P</i> in all regions <i>R</i> of image
1 with binary mask <i>B</i><br>
<br>
If B_P == 255<br>
color region <i>R</i> red<br>
else<br>
color region <i>R</i> green<span class="HOEnZb"><font
color="#888888"><br>
<br>
- Imre</font></span>
<div>
<div class="h5"><br>
<br>
<div>Am 02.01.2016 um 20:16 schrieb David Gobbi:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Sorry, but I still don't follow your
explanation. I have some vague idea of what you
are trying to do, but I don't understand well
enough to give you any concrete advice. Can you
try focussing on just one specific aspect of the
problem, and then once I've understood that one
aspect, we can move forward from there?
<div><br>
</div>
<div> - David</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat, Jan 2, 2016 at
11:46 AM, Imre Goretzki <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:goretzki.imre@gmail.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:goretzki.imre@gmail.com">goretzki.imre@gmail.com</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Mh ok,
I guess I did not explained my problem well
enough.<br>
<br>
The vtkPolyDataConnectivityFilter returns
regions, either the largest, specified,
seeded or all regions (your filter returns
largest, seeded or all). I'm interessted in
the following:<br>
<br>
- all regions<br>
- specified regions.<br>
<br>
The problem is not the filter, the
performance or possible memory leaks, I need
the region's polydata representation because
I have a second object (vtkImageData or
vtkPolyData, binary mask) that has some
additional information, that are not
represented by the data (the input for the
vtkImageConnectivityFilter).<br>
<br>
Imagine the input for the filter as image 1
and the mask as image 2. Both images have
the same dimensions in all 3 directions (x,
y, z) but contain different information.<br>
<br>
image 2 will be transformed to a binary
image mask<br>
<br>
from image 1 i need to extract regions, but
if some (unknown) regions have points that
are located in the binary image mask, I do
not want these regions to be contained in
the extracted region list.<br>
<br>
So it's not about your filter or the
performance, but I have some problems using
this filter for my issue, because I cannot
reach the region's polydata.<br>
<br>
I hope this helps.<span><font
color="#888888"><br>
<br>
- Imre</font></span>
<div>
<div><br>
<br>
<div>Am 02.01.2016 um 18:54 schrieb
David Gobbi:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi Imre, Happy New
Year!
<div><br>
</div>
<div>I've read your email few times,
and I feel that I must be missing
some important because there are
several things that I don't
understand about it.</div>
<div><br>
</div>
<div>The vtkImageConnectivityFilter
is essentially just a connected
component filter. In the output
of this filter, all pixels outside
the mask will be colored black
(they will have a value of zero).
So what I don't understand about
your email is why you say that
non-rectangular regions are a
problem. Are you just worried
about the wasted memory?</div>
<div><br>
</div>
<div> - David</div>
<div><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Sat,
Jan 2, 2016 at 9:00 AM, Imre
Goretzki <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:goretzki.imre@gmail.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:goretzki.imre@gmail.com">goretzki.imre@gmail.com</a></a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div bgcolor="#FFFFFF"
text="#000000"> Hey David,<br>
<br>
first of all: Happy new
year :)<br>
<br>
I have some questions
about your filter. First
of all in part A of the
attached image, is my
understanding of extents,
so if you have a region,
you will get the
x_min/x_max, y_min/y_max
(and z_min/z_max for 3D).
If you do not have
rectangular regions than
you could have some
problems (see part A and
B). In part B you see my
mask. The red rectangle
shows the case that the 4
corners of a 2D region
cannot be directly
checked, because the
region that lies within
this rectangle has little
matches with the mask
(none of the 4 corners are
within the mask). The
green rectangle has 3 out
of 4 edges that lie within
the mask.<br>
<br>
Part C shows one of the
worst cases of this
approach (using extents)
because there is so much
space that does not belong
to the actual region.<br>
<br>
My question: Is it
possible to extend your
filter to directly store
the region data (for each
region, for example as
vtkImageData) if the
extraction mode is set to
"All"?<span><font
color="#888888"><br>
<br>
- Imre</font></span>
<div>
<div><br>
<br>
<div>Am 29.12.2015 um
13:27 schrieb Imre
Goretzki:<br>
</div>
<blockquote
type="cite"> Hi
David,<br>
<br>
thank you. I'll take
a look at your
class.<br>
<br>
Regards<br>
Imre<br>
<br>
<div>Am 29.12.2015
um 13:07 schrieb
David Gobbi:<br>
</div>
<blockquote
type="cite">
<div dir="ltr">Hi
Imre,
<div><br>
</div>
<div>I have a
connectivity
filter that
works directly
on images, it
can label
connected
regions
according to
size and it
should be much
faster
(probably
1000x) than
doing voxel
checks via
polydata:</div>
<div><a
moz-do-not-send="true"
href="https://github.com/dgobbi/AIRS/blob/master/ImageSegmentation/vtkImageConnectivityFilter.h"
target="_blank"><a class="moz-txt-link-freetext" href="https://github.com/dgobbi/AIRS/blob/master/ImageSegmentation/vtkImageConnectivityFilter.h">https://github.com/dgobbi/AIRS/blob/master/ImageSegmentation/vtkImageConnectivityFilter.h</a></a></div>
<div>I'll
probably be
contributing
this filter to
VTK sometime
in the near
future.</div>
<div><br>
</div>
<div> - David</div>
<div><br>
<div
class="gmail_extra"><br>
<div
class="gmail_quote">On
Tue, Dec 29,
2015 at 4:02
AM, Imre
Goretzki <span
dir="ltr"><<a
moz-do-not-send="true" href="mailto:goretzki.imre@gmail.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:goretzki.imre@gmail.com">goretzki.imre@gmail.com</a></a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0px
0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div
bgcolor="#FFFFFF"
text="#000000">
Is there an
easier way in
ITK?<br>
<br>
Thanks<span><font
color="#888888"><br>
Imre</font></span>
<div>
<div><br>
<br>
<div>Am
28.12.2015 um
23:38 schrieb
Imre Goretzki:<br>
</div>
<blockquote
type="cite">
Hey guys,<br>
<br>
I use the
vtkPolyDataConnectivityFilter
from polydata
to extract
several
different and
more or less
unknown
regions. <br>
My problem is
that I want to
extract
regions from
this filter,
but if I do
this, the
update process
for all
regions takes
up to
10minutes:<br>
<br>
filter->SetExtractionModeToAllRegions();<br>
filter->Update();<br>
...<br>
<br>
for (int i =
0; i <
filter->GetNumberOfExtractedRegions();
i++)<br>
{<br>
extractFilter->InitializeSpecifiedRegionList();<br>
extractFilter->AddSpecifiedRegion(i);<br>
extractFilter->Modified();<br>
extractFilter->Update();<br>
extractRegionData->DeepCopy(extractFilter->GetOutput());<br>
}<br>
extractFilter->InitializeSpecifiedRegionList();<br>
<br>
Background for
this: I want
to use the
points of each
region to
check whether
they lie
within an
object in my
binary<br>
mask image. So
the pipeline
would be like
this:<br>
<br>
1) Get all
Regions <br>
2) get
region <i>i</i><br>
3)
get points of
region <i>i</i><br>
4) check if
point <i>j</i>
lies within
the binary
mask <i>B</i>
(<i>B</i>_<i>j</i>
== 255)<br>
4a) if true
then add
region to the
extractFilter
and break
(-> next
region <i>i</i>)<br>
4b) if false
then continue
with next
point <i>j</i><br>
5) Mark all
regions red
(done easily)<br>
6) Mark some
regions green
that are above
a specific
size (can be
accessed with
filter->GetRegionSizes()
)<br>
7) Mark some
regions yellow
(the regions
that are
extracted
during step
1-4a) <br>
<br>
I do not know
if the
PolyDataConnectivityFilter
is the right
class for
this, I think
it is. <br>
If I store the
extractRegionData
in a vector,
all regions
have the same
number of
points (which
is kind of
strange) but
different
number of
cells (region
size == number
of cells is
correct).<br>
<br>
I would now
try to get the
points from
the cells and
check the
binary mask,
because the <br>
<br>
vtkPolyData->GetNumberOfPoints()<br>
<br>
and<br>
<br>
vtkPolyData->GetPoint(pointCounter,
point); <br>
<br>
are not
working
correctly in
this scenario
(all regions
are extracted
because every
single region
has every
point?<br>
i did not
verify my
guess but I
think there
would be the
problem)<br>
<br>
The binary
mask is a
vtkImageData,
that could be
transformed to
vtkPolyData.<br>
The input
image (already
filtered with
vtkMarchingCubes)
and the binary
mask have the
same
dimensions
(x,y,z).<br>
<br>
I hope you can
imagine what
I'm trying to
do and have
some tips for
me, if my
approach is
correct.<br>
<br>
Regards<br>
Imre</blockquote>
</div>
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