[IGSTK-Users] Multiple tracking systems

[alberto.vaccarella at mail.polimi.it]

Hi Patrick,
thanks for your quick answer.
About the calibration, I performed it separately, and I'm going to  
integrate everything in a unique application taking advantage of the  
TransformWriter and TransforReader classes.
I will try your suggestions as soon as possible and let you know.

Alberto





Citando Patrick Cheng <cheng at isis.georgetown.edu>:

> Hi Alberto,
>
> Your approach is quite novel. Normally people think about register EM
> and Optical trackers together first, now you are tracking the EM
> tracker using Optical tracker.
>
> 1. One quick question:
> Did you calibrate the EM FieldGenerator with the opticalTrackerTool(0)?
> opticalTrackerTool(0) --> FieldGeneratorBoxObject
>
> You need to have this transform set properly to get the accurate
> position of the EM sensor in the optical tracker space.
>
> 2. To answer your question about what should be added to View3D.
>    You need to add also the spatial objects into View3D so it can render it.
>    You also need to connect your View3D to the scene graph tree, so it
> knows where to render those objects. In this case, you should try:
>
> View3D --> opticalTracker --> opticalTrackerTool(0) -->
> FieldGeneratorBoxObject --> magneticTracker --> magneticTrackerTool -->
> EM_Sensor_CylinderObject
>
> Hope this helps,
>
> Patrick
>
>
> alberto.vaccarella at mail.polimi.it wrote:
>> Hi everyone,
>>
>> I'm trying to develop an application using both an optoelectronic   
>> and a magnetic tracking system, the setup is as follows:
>>
>> - the optoelectronic device tracks some tools and the EM field generator
>>
>> - the magnetic device tracks one sensor with respect to the   
>> coordinate system of its EM field generator
>>
>> I want all the tools and the EM sensor to be displayed in the same   
>> coordinate system (the optical device one); to do that I:
>>
>> - instantiated 2 tracker controllers
>> - built the scene graph as follows (after the tracking has started ):
>>
>> opticalTracker --> opticalTrackerTool(0) -->   
>> FieldGeneratorBoxObject --> magneticTracker --> magneticTrackerTool  
>>  --> EM_Sensor_CylinderObject
>>
>> where:
>> - opticalTrackerTool(0) is the rigid body associated to the EM   
>> field generator
>>
>> Is this approach correct? What should I add to the view3D? I added   
>> the representations of the two objects but it doesn't work, it   
>> doesn't display anything...
>> Once I solve this I guess I have to use:
>>
>>      EM_Sensor_CylinderObject->RequestComputeTransformTo(opticalTracker)
>>
>> I'm not sure I got how to use this method...should I call it once   
>> or each time I need the transform? How could I make the   
>> EM_Sensor_CylinderObject to be always displayed in the   
>> opticalTracker coordinate system?
>>
>> Thanks in advance for any help
>> Alberto
>>
>>
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