<div dir="ltr"><div class="markdown-here-wrapper" style="font-family:"Lucida Sans",Cantarell,Verdana,sans-serif;color:rgb(11,83,148)"><p style="margin:0px 0px 1.2em!important">Hi,</p>
<p style="margin:0px 0px 1.2em!important">First of all, you should not be calling <code style="font-size:0.95em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(218,218,218);background-color:rgb(232,232,232);border-radius:3px;display:inline">vtkSmartPointer<vtkImageData>::New()</code> for <code style="font-size:0.95em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(218,218,218);background-color:rgb(232,232,232);border-radius:3px;display:inline">data</code> if you intend to use that variable for storing the output from <code style="font-size:0.95em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(218,218,218);background-color:rgb(232,232,232);border-radius:3px;display:inline">reader</code>. That way you don’t end up with a dangling pointer/memory leak.</p>
<p style="margin:0px 0px 1.2em!important">Secondly, note that the output from the reader is not available until <code style="font-size:0.95em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(218,218,218);background-color:rgb(232,232,232);border-radius:3px;display:inline">reader->Update()</code> is called. The faster portion of your code is fast because the reslice viewer has been just getting a default <code style="font-size:0.95em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(218,218,218);background-color:rgb(232,232,232);border-radius:3px;display:inline">vtkImageData</code> object.</p>
<p style="margin:0px 0px 1.2em!important">As for slowness you see, could you please provide details on the data type and size and how much time is spent in <code style="font-size:0.95em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(218,218,218);background-color:rgb(232,232,232);border-radius:3px;display:inline">SetInputData</code>?</p>
<p style="margin:0px 0px 1.2em!important">Hope that helps,<br>Sankhesh</p>
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YW5raGVzaDwvZz48L2Rpdj4=" style="height:0;width:0;max-height:0;max-width:0;overflow:hidden;font-size:0em;padding:0;margin:0"></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Fri, Feb 9, 2018 at 11:22 AM ochampao <<a href="mailto:ochampao@hotmail.com">ochampao@hotmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello vtkusers!<br>
<br>
I am experimenting with a simple dicom viewer similar to the FourPaneViewer<br>
example (see [1] for link). But I am observing a behaviour which I can't<br>
explain. In particular, when I place the<br>
vtkResliceImageViewer::SetInputData()<br>
calls before calling the vtkDICOMImageReader::Update(), the dataset is<br>
loaded extremely fast (approximately 2 seconds). However when<br>
vtkResliceImageViewer::SetInputData() calls are placed after<br>
vtkDICOMImageReader::Update(), then loading the dataset requires<br>
significantly more time to load (approximately 22 seconds). See minimal<br>
code example below.<br>
<br>
Why is the code slower when executed after the Update() call and how can<br>
this be avoided?<br>
<br>
Is it wrong to place the SetInputData() call after Update()? If yes, how can<br>
the vtkImageData object be passed to SetInputData() so that it is still<br>
fast?<br>
<br>
For the slower case, when stepping through the code with the debugger, I can<br>
see that the call to Update() is still fast but the debugger spends most of<br>
its time at SetInputData().<br>
<br>
Eventually, what I'd like to do is group the code that reads the dicom into<br>
a separate function that returns a vtkImageData reference to the pipeline.<br>
But from this experiment it seems to work very slow.<br>
<br>
Thanks,<br>
Panos.<br>
<br>
=======<br>
<br>
Here is a minimal example of my code to demonstrate the two situation<br>
(commented is the slow case):<br>
<br>
void addImage(const char* filename)<br>
{<br>
vtkSmartPointer< vtkDICOMImageReader > reader =<br>
vtkSmartPointer< vtkDICOMImageReader >::New();<br>
reader->SetDirectoryName(filename);<br>
<br>
vtkSmartPointer<vtkImageData> data =<br>
vtkSmartPointer<vtkImageData>::New();<br>
<br>
data = reader->GetOutput();<br>
<br>
//---------------------------------------<br>
// SetInputData() works very fast if here<br>
resliceImageViewer1->SetInputData(data);<br>
resliceImageViewer2->SetInputData(data);<br>
resliceImageViewer3->SetInputData(data);<br>
// ---------------------------------------<br>
<br>
reader->Update();<br>
<br>
//---------------------------------------<br>
// SetInputData() works very slow if here<br>
//<br>
//resliceImageViewer1->SetInputData(data);<br>
//resliceImageViewer2->SetInputData(data);<br>
//resliceImageViewer2->SetInputData(data);<br>
//---------------------------------------<br>
<br>
/*<br>
code to setup widgets (orientation, slice#, window/level color)<br>
*/<br>
<br>
resliceImageViewer1->Render();<br>
resliceImageViewer2->Render();<br>
resliceImageViewer3->Render();<br>
}<br>
<br>
========<br>
References:<br>
<br>
[1]:<br>
<a href="https://github.com/Kitware/VTK/tree/master/Examples/GUI/Qt/FourPaneViewer" rel="noreferrer" target="_blank">https://github.com/Kitware/VTK/tree/master/Examples/GUI/Qt/FourPaneViewer</a><br>
<br>
<br>
<br>
--<br>
Sent from: <a href="http://vtk.1045678.n5.nabble.com/VTK-Users-f1224199.html" rel="noreferrer" target="_blank">http://vtk.1045678.n5.nabble.com/VTK-Users-f1224199.html</a><br>
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</blockquote></div>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div class="inbox-inbox-inbox-inbox-inbox-inbox-inbox-markdown-here-wrapper" style="font-family:"proza libre",sans-serif;color:rgb(0,56,107)"><h5 id="inbox-inbox-inbox-inbox-inbox-inbox-inbox-sankhesh-jhaveri" style="margin:1.3em 0px 1em;padding:0px;font-size:1.1em;border-bottom-width:1px;border-bottom-style:solid;border-bottom-color:rgb(238,238,238);font-weight:bold;color:rgb(11,65,148)">Sankhesh Jhaveri</h5>
<h6 id="inbox-inbox-inbox-inbox-inbox-inbox-inbox--sr-research-development-engineer-kitware-http-www-kitware-com-518-881-4417" style="margin:1.3em 0px 1em;padding:0px;font-size:1em;color:rgb(11,83,148);font-family:"open sans",sans-serif;font-weight:normal"><em>Sr. Research & Development Engineer</em> | <a href="http://www.kitware.com/">Kitware</a> | (518) 881-4417</h6>
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