[IGSTK-Users] Numerous Transform Callback Performance

[Jake McIvor]

Thanks Alvaro,

I found a similar bug in my code - I was calling
ObserveTransformEventsFrom() in my callback function, adding an additional
observer each time.  Correcting that has fixed the decreasing rate over
time.

~Jake


2010/5/13 Alvaro Gómez <agomez at fing.edu.uy>

> Hi Jake:
>
> We had a similar problem when acquiring repeatedly sets of N transforms.
>  We were using a code similar to that of igstkPivotCalibration. For each set
> of N transforms we were adding a new observer
> (TrackerToolTransformUpdateEvent) to the trackertool and then after each
> set, the acquisition performance degraded as the same transform was
> retrieved more times. We were forgetting to remove the observer after each
> set.
>
> Hope it helps but most probably the problem is not as simple as this.
>
> Best regards,
> Alvaro
>
>
> El día miércoles, 12 de mayo de 2010 04:04:45 p.m.
> Jake McIvor <jdmcivor at interchange.ubc.ca>
> escribió:
>
>> I have an application that logs transform data to a file.  A callback
>> function is attached to an observer watching for
>> TrackerToolTransformUpdateEvent.  Within the callback function I use a
>> transform observer to check for and get the latest transform, and then log
>> it to a file.
>>
>> Over time, the rate at which these transforms are recorded drops
>> significantly.  I came across a section of Christopher Heath's thesis,
>> Disablement of a Surgical Drill Via CT Guidance to Protect Vital Anatomy
>> that describes a similar issue:
>>
>> "A method was added to Landmark3DRegister to allow for pass by reference
>> retrieval of transforms instead of using callbacks. This was implemented to
>> prevent an issue that occurs with the callback method utilized by IGSTK when
>> finding the transform many times."
>>
>> Does anyone have any insight on what is happening or how to improve
>> performance?
>>
>> Cheers,
>>
>> Jake
>>
>> --
>> Jake McIvor
>> MASc Candidate, Biomedical Engineering
>> University of British Columbia
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Follow this link to subscribe/unsubscribe:
>> http://public.kitware.com/cgi-bin/mailman/listinfo/igstk-users
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/igstk-users/attachments/20100513/111008d1/attachment-0001.html>