[vtkusers] Major speed up (was Re: vtkImageViewer2 / vtkImageActor (was Re: Sample code using VTK and DICOM))

[Mathieu Malaterre]

On Fri, Oct 3, 2008 at 11:52 AM, Mathieu Malaterre
<mathieu.malaterre at gmail.com> wrote:
> 'lo
>
> On Fri, Oct 3, 2008 at 11:41 AM, masabumi ishihara
> <maty.ishihara at gmail.com> wrote:
>> Hi Mathieu,
>>
>> Thank you for your splendid opinion.
>> This time, we compareed two viewers' preformances.
>> Unfortunately, the results are as follows;
>>
>>                                                      CPU rate
>> performance of moving
>>   gdcmviewer with release mode          50~60%                slow
>>   our prototype viewer                         50~60%              real time
>>
>>   DICOM Data : LittleEndianExplicit  15,000 KB
>
> hum... for a 2D slice ? This is not that small after all. Maybe you
> are suffering from the non-power of two issue in OpenGL + texture.
>
> What is the size of the image (it is printed in the output of
> gdcmviewer). Something like:
>
> ...
>  Bounds:
>    Xmin,Xmax: (0, 347.85)
>    Ymin,Ymax: (424.05, 848.1)
>    Zmin,Zmax: (0, 0)
>  Compute Time: 0
>  ScalarType: 5
>  NumberOfScalarComponents: 1
>  Spacing: (0.15, 0.15, 1)
>  Origin: (0, 424.05, 0)
>  Dimensions: (2320, 2828, 1)
>  Increments: (0, 0, 0)
>  Extent: (0, 2319, 0, 2827, 0, 0)
> ...
>
>> Can you believe the above results?
>> Do you have any reason, e.g. memory sled ..., ?
>> Our prototype viewer is simple 2D viewer, which doesn't have any interface
>> to VTK, ITK GDCM.
>> Then, we would like to use the other viewer for the future.
>> But, it have to be real time operative.
>
> Because this is not my area of knowledge, I'll have to ask other
> people if there is anything to do to speed things up. Maybe some
> OpenGL guru will answer...

This is fixed in VTK CVS, backporting patch to VTK 5.2 do fix the
issue also for me:

http://public.kitware.com/cgi-bin/viewcvs.cgi/Rendering/vtkOpenGLImageActor.cxx?r1=1.37&r2=1.38&view=patch

thanks to Francois !

-- 
Mathieu