[vtkusers] Strange slowness with vtkImagePlaneWidget

[Marco Sambin]

Hi Dean,

first of all, thank you for your message.

The underlying pixel data type is unsigned short for both volumes.
Here is how I configure the reader:

        imageReaderVTK =  new vtkImageReader2();
        imageReaderVTK.FileLowerLeftOn();
        imageReaderVTK.SetFilePrefix(filePrefix);
        imageReaderVTK.SetFilePattern("%s_%d.raw");
        imageReaderVTK.SetDataExtent(0, sliceCols - 1,
                              0, sliceRows - 1,
                              0, numOfImages - 1);
        imageReaderVTK.SetDataSpacing(xSpacing, ySpacing, zSpacing);
        imageReaderVTK.SetDataOrigin(0.0, 0.0, 0.0);
        imageReaderVTK.SetDataScalarTypeToUnsignedShort();
        imageReaderVTK.SetDataByteOrderToBigEndian();
        imageReaderVTK.UpdateWholeExtent();


And here is how I configure the widget:

    vtkGenericRenderWindowInteractor interactor =
getRenderWindowInteractor();
    planeWidgets[planeWidgetIndex].RestrictPlaneToVolumeOn();
    planeWidgets[planeWidgetIndex].SetInteractor(interactor);
    planeWidgets[planeWidgetIndex].DisplayTextOn();
    planeWidgets[planeWidgetIndex].TextureInterpolateOn();
    planeWidgets[planeWidgetIndex].UserControlledLookupTableOff();
    planeWidgets[planeWidgetIndex].SetResliceInterpolateToCubic();
    planeWidgets[planeWidgetIndex].KeyPressActivationOff();

planeWidgets[planeWidgetIndex].SetInputConnection(imageReaderVTK.GetOutputPort());
    planeWidgets[planeWidgetIndex].SetWindowLevel(winWidth, winLevel, 0);
    planeWidgets[planeWidgetIndex].SetPlaneOrientation(planeWidgetIndex);

    planeWidgets[planeWidgetIndex].PlaceWidget(volBounds);
    planeWidgets[planeWidgetIndex].On();
    planeWidgets[planeWidgetIndex].SetEnabled(1);

As I explained in my previous post, strangely the widgets interact with
much better performances when my volume is made up of 360 512x512 slices,
and worse when my volume is made up of 90 512x512 slices.
But this only happens on the old PC. On my development machine the
rendering performance of the widgets are fine and undistinguishable in both
cases.

I would like to underline that, on the old machine and with the smaller
volume, the rendering of the vtkImagePlaneWidget is slow even when I try to
modify the camera position through the default VTK interactor. I do not
trigger any recomputation of window/level, or other, just roll my camera
around the volume, and still I see the rendering slowness (I can
distinguish painting of each triangle of each texture).

Thanks in advance for sharing your comments and suggestions with me.

Marco



On Wed, Sep 4, 2013 at 4:21 PM, Dean Inglis <inglis.dl at gmail.com> wrote:

> Hi Marco,
>
> what is the underlying pixel data type in those two images ?  The widget
> has an internal
> vtkImageMapToColors which will do additional processing to convert the
> input to
> uchar if required.  How do you configure your widgets ?
>
>
> - Dean
>
>
> On Wed, Sep 4, 2013 at 7:08 AM, Marco Sambin <m.sambin at gmail.com> wrote:
>
>> Hi all.
>>
>> In my VTK6-based Java application, I am using a vtkCanvas where I display
>> three orthogonal vtkImagePlaneWidgets, cutting a volume loaded
>> through vtkImageReader2.
>>
>> Everything works fine on my development machine, which is a recent and
>> moderately-powerful 64-bit Win 7-based machine.
>>
>> For legacy-compatibility purposes, I tested this application under an
>> older Win XP-based Pentium 4 machine with 1 GB RAM and old Barco graphic
>> cards, and I obtained "strange" results:
>>
>> - if I feed vtkImageReader2 with a volume made up of around 360 raw
>> slices, each one 512x512 pixels, then the overall rendering performances of
>> the view containing the three vtkImagePlaneWidgets are acceptable.
>>
>> - on the other side, if I feed vtkImageReader2 with a volume made up of
>> 90 (i.e., fewer) raw slices, each one 512x512 pixels, then the overall
>> rendering performances of the view containing the three
>> vtkImagePlaneWidgets become really poor, and I can distinguish the texture
>> appearing on top of each plane widget painting as two separate triangles,
>> given the slow rendering.
>>
>> Can you guess why the rendering performance of the vtkImagePlaneWidgets
>> are much worse with the smaller volume w.r.t. with the larger volume?
>>
>> Thanks for any hints you will give.
>>
>> Best regards,
>>
>> Marco
>>
>>
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