Camera Focus when using custom Active Markers (LEDs)

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JosephMatan
Posts: 17
Joined: Sun Jan 05, 2020 8:52 am

Camera Focus when using custom Active Markers (LEDs)

Post by JosephMatan » Mon Feb 03, 2020 7:43 am

Hi,

I've a setup of Prime 17W cameras, and a set of rigid bodies that were built from custom active markers (IR LED's), so the IR LED's of the cameras are off (so I can't see anything in the grayscale mode, except the custom active markers).

Does changing the aperture (to control the focus) should effect the accuracy of tracking my markers (or is it relevant only for passive/reflecting markers) ?

Thanks,
Joseph

steven.andrews
NaturalPoint Employee
NaturalPoint Employee
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Re: Camera Focus when using custom Active Markers (LEDs)

Post by steven.andrews » Mon Feb 03, 2020 12:36 pm

Hi Joseph,

Changing the aperture or the focus will affect both passive and active markers. Since the IR LEDs usually have a smaller angle of illumination, it is best to focus to them. Doing this will provide the best results for the LEDs, and this should also provide an optimum focus for the usual passive markers.

Best,
Steven
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Steven Andrews
OptiTrack | Senior Customer Support Engineer
help.naturalpoint.com
support@optitrack.com

JosephMatan
Posts: 17
Joined: Sun Jan 05, 2020 8:52 am

Re: Camera Focus when using custom Active Markers (LEDs)

Post by JosephMatan » Wed Feb 05, 2020 4:56 am

Thanks !!!
If possible, I have another two questions on that issue:

1. Before starting the calibration process, is there any recommendation which features should be set first (aperture, focus and exposure) ?
I mean, in what order. For example, should all the features should first be set to the maximum (or minimum), and then set the aperture, then the focus and at last set the exposure (it was just an arbitrary example).
I hope I was clear enough.

2. When I'm using a custom active markers (LEDS), should I use the 250mm wand for smaller volumes (since the LEDs are much smaller than the passive markers) ?

Thanks,
Joseph

steven.andrews
NaturalPoint Employee
NaturalPoint Employee
Posts: 575
Joined: Mon Jan 19, 2015 11:52 am

Re: Camera Focus when using custom Active Markers (LEDs)

Post by steven.andrews » Thu Feb 06, 2020 1:15 pm

My pleasure Joseph!

When setting the cameras, you usually want to lock down the aperture before focusing. Exposure settings, in Motive, could be adjusted later if you need to increase the light seen by the cameras.

The wand size is really more about the size of the capture area. If you are capturing the active markers in a small area, the 250 will probably calibrate the volume more easily. Otherwise, the 500 is just fine for a bigger tracking area, regardless of the marker type.

Cheers,
Steven
--
Steven Andrews
OptiTrack | Senior Customer Support Engineer
help.naturalpoint.com
support@optitrack.com

JosephMatan
Posts: 17
Joined: Sun Jan 05, 2020 8:52 am

Re: Camera Focus when using custom Active Markers (LEDs)

Post by JosephMatan » Sun Feb 09, 2020 1:44 am

Great Steven!!
Thank you very much for the support !!!

Best regards,
Joseph

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