Hi Alex,

The input for the two CameraVisualization filters are position data (an 
NDIDataSource object i believe). We had initially clubbed the two filters 
togethor, however the need to operate on separate Camera objects, and we 
thought it would be easier to create another instance rather than extend the 
methods.

However, we tried without any of the CameraVisualization filters, that is just 
the Visualization filter object (disabling the other two render windows) and 
the same effects were noticed!

Best regards,

Yashodhan

----- Original Message -----
From: "Alexander Seitel" <[email protected]>
To: "Keshav Chintamani" <[email protected]>, "Jochen 
Neuhaus" <[email protected]>
Cc: "[email protected]" <[email protected]>, 
"Ingmar Wegner"
<[email protected]>, "Marco Nolden" <[email protected]>, 
"Yashodhan Nevatia"
<[email protected]>
Sent: Thursday, 26 May, 2011 7:24:41 PM
Subject: AW: AW: AW: [mitk-users] Very low frame rates observed

Hi Keshav,



I was just wondering what are the current input of your
CameraVisualization filters for „RightEye“ and „LeftEye“? I realized
that in the current implementation only input 0 is taken for setting the
camera according to the input navigation datas.

You could extend the CameraVisualization class by a member defining the
actual input taken for camera visualization (default=0) and then combine
the filters sequentially to avoid multiple Update() calls:
VisualizationFilter->CameraVisualization1->CameraVisualization2.
CameraVisualization2->Update() should then result in an update of the
whole pipeline.



Regards,

Alex





Von: Keshav Chintamani [mailto:[email protected]]
Gesendet: Donnerstag, 26. Mai 2011 16:46
An: Neuhaus, Jochen
Cc: Seitel, Alexander; '[email protected]'; Wegner,
Ingmar; Nolden, Marco; Yashodhan Nevatia
Betreff: Re: AW: AW: [mitk-users] Very low frame rates observed



Hi Alex,

We did an update on the TrackingDeviceSource object alone, but there was
nothing rendered. I assume that as this object is at the start of the
pipeline, it does not propogate to the renderers. We removed Update()
calls on the two camera visualizer filters and called update only on the
mitk::NavigationDataObjectVisualizationFilter (m_Visualizer) object.
That improved the frame rate, but now we have no HMD rendering

Hi Jochen:

We have been updating only the 3D renderwindow so far. Without that
call, nothing renders.


Best,

Keshav


On 5/26/2011 4:33 PM, Neuhaus, Jochen wrote:

Hi Keshav,



2D rendering is quite slow in MITK, especially when the scene contains
3D surfaces.

You could try to update only the 3D renderwindow(s):

mitk::RenderingManager::GetInstance()->RequestUpdate(this->GetActiveStdMultiWidget()->GetRenderWindow4()->GetRenderWindow());



This should improve the frame rate compared to a RequestUpdateAll()
call.



Regards,

Jochen






Von: Keshav Chintamani [ mailto:[email protected]
]
Gesendet: Donnerstag, 26. Mai 2011 16:24
An: Seitel, Alexander
Cc: [email protected] ; Wegner, Ingmar; Neuhaus, Jochen;
Nolden, Marco
Betreff: Re: AW: [mitk-users] Very low frame rates observed



Hi Alex,

Thanks for the quick reply! In our 16 ms timed function call, we do have
a RequestUpdateAll(). But removing it results in no rendering or update
of the graphics objects. As part of the requirements we need to update
the renderers at 16ms. However this is impossible to achieve with the
current implementation. When we use ForceImmediateUpdateAll(), it causes
a crash. This probably because another process is also updating a
renderer at the same time.

Is there an alternative method of updating the renderers at a 60 hz
frequency?

Best,

Keshav

On 5/26/2011 3:32 PM, Seitel, Alexander wrote:

Hi Keshav,



your IGT-pipeline initialization looks fine. Perhaps you should try to
call Update() only once on the TrackingDeviceSource associated to the
NDI Polaris instead of calling it for every filter. Do you also
repeatedly update the rendering process with e.g. RequestUpdateAll()?
Try to minimize those update calls as they will result in triggering the
whole IGT-Pipeline / Rendering mechanism.



Please let us know if you have any success with this.



Best regards,

Alex





Von: Keshav Chintamani [ mailto:[email protected]
]
Gesendet: Donnerstag, 26. Mai 2011 14:16
An: [email protected]
Cc: Wegner, Ingmar; Neuhaus, Jochen; Nolden, Marco
Betreff: [mitk-users] Very low frame rates observed



Hello MITK users,

We are using the filters in the mitkIGT module for an head mounted
display based augmented reality application and have some concerns
regarding the filter pipelines. In particular, the frame rates obtained
during rendering is very low.

We use a NDI Polaris spectra with 5 rigid bodies.

Essentially, there are three filter objects:

mitk::NavigationDataObjectVisualizationFilter::Pointer m_Visualizer


mitk::CameraVisualization::Pointer m_LeftEye


mitk::CameraVisualization::Pointer m_RightEye


which are initialized once and passed the required parameters:
-----------------------------------------------------------------------------
//Create instances of camera visualizers for left and right HMDs
m_TrackingManager->m_CameraVisualizerLeftHMD =
mitk::CameraVisualization::New();
m_TrackingManager->m_CameraVisualizerRightHMD
=mitk::CameraVisualization::New();

//set Renderer
m_TrackingManager->m_CameraVisualizerLeftHMD->SetRenderer(mitk::BaseRenderer::GetInstance(leftWin->GetRenderWindow()->GetRenderWindow()));
m_TrackingManager->m_CameraVisualizerRightHMD->SetRenderer(mitk::BaseRenderer::GetInstance(rightWin->GetRenderWindow()->GetRenderWindow()));

//set viewing direction
mitk::Vector3D viewVector;
mitk::FillVector3D( viewVector, 0.0, 0.0, -1.0 );
m_TrackingManager->m_CameraVisualizerLeftHMD->SetDirectionOfProjectionInToolCoordinates(viewVector);
m_TrackingManager->m_CameraVisualizerRightHMD->SetDirectionOfProjectionInToolCoordinates(viewVector);

//set view up vector
mitk::Vector3D upVector;
//mitk::FillVector3D( upVector, -1.0, 0.0, 0.0 );
mitk::FillVector3D( upVector, 0.0, 1.0, 0.0 );

m_TrackingManager->m_CameraVisualizerLeftHMD->SetViewUpInToolCoordinates(upVector);
m_TrackingManager->m_CameraVisualizerLeftHMD->SetViewAngle(50);
m_TrackingManager->m_CameraVisualizerLeftHMD->SetFocalLength(500);

m_TrackingManager->m_CameraVisualizerRightHMD->SetViewUpInToolCoordinates(upVector);
m_TrackingManager->m_CameraVisualizerRightHMD->SetViewAngle(50);
m_TrackingManager->m_CameraVisualizerRightHMD->SetFocalLength(500);

m_TrackingManager->m_Visualizer->SetInput(i,
m_TrackingManager->GetNavDataFromIndex(i)); // set input for
visualization filter

m_TrackingManager->GetToolNameFromIndex(i);
mitk::DataNode::Pointer toolrepresentationNode =
m_TrackingManager->CreateGizmoRGBNode(toolName.c_str());
pDataStorage->Add(toolrepresentationNode);
m_TrackingManager->m_Visualizer->SetRepresentationObject(i,
toolrepresentationNode->GetData()); // set instrument nodes as baseData
for visualisation filter

-----------------------------------------------------------------------------



m_Visualizer updates the 6 polydata corresponding to each tool in the
multi-widget 3D renderwindow

m_LeftEye updates the HMD left eye viewpoint in a QMITKRenderWindow

m_RightEye updates the HMD right eye viewpoint in a different
QMITKRenderWindow.



A figure describing our filter update and a code snippet is attached.

// NavigationDataFiltersUpdate() is called by a Qt signal-slot on a
timer update every 50 ms
void CamdassTrackingManager::NavigationDataFiltersUpdate()
{

if(m_NDITrackingDevice.IsNull())
{ return;
} if (m_Visualizer.IsNull())
return;

m_Visualizer->Update();

if(m_CameraVisualizerLeftHMD.IsNotNull() &&
m_CameraVisualizerRightHMD.IsNotNull()) {
m_CameraVisualizerLeftHMD->Update();
m_CameraVisualizerRightHMD->Update();

}
}

Every 50ms, these filters are updated using the ->Update() call.

1. When the tracking is initialized, using FRAPS we see a very low frame
rate of 3 to 20 fps on the renderwindows
2. When the tracking is initialized, using the mouse interactor
(rotating the view) on the renderwindow raises the frame rate slightly
3. However when the tracking pipeline is not initialized, and we use the
mouse to rotate the 3D renderwindow, we get a frame rate of 56-60 hz



Is there a reason for the rendering rate to drop so low in the
QmitkRenderWindows with the tracking running? And is calling Update() on
the filters the correct way to push/pull data from the NDI device?

Any help to rectify this issue is welcome!

Regards,

Keshav






-- Keshav Chintamani, Systems Engineer Space Applications Services NV
Leuvensesteenweg 325 1932 Zaventem Belgium Tel: +32 2 721 54 84 Fax: +32
2 721 54 44 URL: http://www.spaceapplications.com





-- Keshav Chintamani, Systems Engineer Space Applications Services NV
Leuvensesteenweg 325 1932 Zaventem Belgium Tel: +32 2 721 54 84 Fax: +32
2 721 54 44 URL: http://www.spaceapplications.com




-- Keshav Chintamani, Systems Engineer Space Applications Services NV
Leuvensesteenweg 325 1932 Zaventem Belgium Tel: +32 2 721 54 84 Fax: +32
2 721 54 44 URL: http://www.spaceapplications.com

-- 
Yashodhan Nevatia
Systems Engineer

Space Applications Services
Leuvensesteenweg 325
B-1932 Zaventem
Belgium
Tel:  +32 (0)2-721.54.84
Fax:  +32 (0)2-721.54.44
URL: www.spaceapplications.com

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