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OptiTrack API
Version: 1.81
For SDK Version 1.1.034

"4.1.5.1.9 INPVector2:: get_imagerMMFocalLength
Returns the focal length of the lens used with the imager in millimeters.
TrackIR3/SmartNAV3/OptiTrack FLEX:3 stock lens = 3.7mm
TrackIR4 stock lens = 2.45mm
OptiTrack FLEX:C120 stock lens= 2.6mm"

This function returns 3.7mm for a TrackIR 4 but the documentation says it should be 2.45mm. Is this function reliable? Are there TrackIR 4 units with 3.7mm lenses?

In the OptiTrack SDK the default Focal Length value of INPVector is only set for TrackIR 3 cameras. Use the supplied values to override it.

So INPVector is returning a default focal length, independent of the camera type? In which case Optitrack needs to be able to identify between cameras. But there is no mention of TrackIR 4 in the INPCamera Model enumeration, the Revision mentions a 'TrackIR Pro' and 'TrackIR Basic' but to my knowledge both the TrackIR 3 and TrackIR 4 are 'Pro'. Any ideas?

Does the imagerMMWidth function return correct values for the camera in use?

Please also note that the INPVector3 functionality you are using is not officially supported, see this post for more information.
http://forum.naturalpoint.com/forum/ubb ... #Post30181

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Use GetOption() and NP_OPTION_HARDWARE_REVISION to tell the difference between TrackIR 3 and 4.


TRACKIR3_PIXELWIDTH = 355
TRACKIR3_PIXELHEIGHT = 290
TRACKIR3_IMAGERWIDTH = 2.2
TRACKIR3_IMAGERHEIGHT = 1.8
TRACKIR3_FOCALLENGTH = 3.70

TRACKIR4_PIXELWIDTH = 355
TRACKIR4_PIXELHEIGHT = 290
TRACKIR4_IMAGERWIDTH = 2.2
TRACKIR4_IMAGERHEIGHT = 1.8
TRACKIR4_FOCALLENGTH = 2.45

C120_PIXELWIDTH = 355
C120_PIXELHEIGHT = 290
C120_IMAGERWIDTH = 2.2
C120_IMAGERHEIGHT = 1.8
C120_FOCALLENGTH = 2.6

V100_PIXELWIDTH = 640
V100_PIXELHEIGHT = 480
V100_IMAGERWIDTH = 3.84
V100_IMAGERHEIGHT = 2.88
V100_FOCALLENGTH = 4.5

SMARTNAV4_PIXELWIDTH = 640
SMARTNAV4_PIXELHEIGHT = 480
SMARTNAV4_IMAGERWIDTH = 3.84
SMARTNAV4_IMAGERHEIGHT = 2.88
SMARTNAV4_FOCALLENGTH = 4.9

TRACKIR5_PIXELWIDTH = 640;
TRACKIR5_PIXELHEIGHT = 480;
TRACKIR5_IMAGERWIDTH = 3.84;
TRACKIR5_IMAGERHEIGHT = 2.88;
TRACKIR5_FOCALLENGTH = 3.99;

Thanks for those numbers, I appreciate it (it would also be nice if they came in the header file ).

I'm not using INPVector functionality, I incorrectly assumed that it was able to report the camera lens and imager specifications. I guess if this ability were available it would be via INPCamera.

TrackIR 4 returns:
Model: NP_HW_MODEL_TRACKIR
Revision: NP_HW_REVISION_TRACKIR_PRO
I'm not sure what a TrackIR 3 would return though. Would its Revision be NP_HW_REVISION_TRACKIR_BASIC?

The model type defines are for use with get_Model() and get_Revision(), but not for use with NP_OPTION_HARDWARE_REVISION. It refers to the physical hardware generation.

For NP_OPTION_HARDWARE_REVISION the following would apply :