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Hey there ! I wanted to ask if there is an optimal number of ios devices for a change of direction tasks (especially 180 degrees ) ? Is there any difference between 2 or 3 for example ? Thanks a lot !

Hi Marios,

I would suspect that 3 cameras would be better for this type of collection. 2 could work, but you would probably run into some problems with occlusions.

Hope this helps,
Matt

Hi,
I wanted to post a follow-up question here:

I have recorded some walking trials with a setup of four iPhones, but I've run into a problem. Two front-facing cameras can see the subject at all times, but as the person enters the capture volume of two cameras, which have been placed viewing the saggital plane, some models are shaky shortly after they enter the latter two cameras. This is not consistent, however- some trials work just fine.
Could this problem occur because the capture volume should be similar for all cameras?

Is there any way to ignore the videos of the two side-facing cameras and just use the two which view the person from the front?

kind regards,

Laura

Hi Laura,

In general, the best way to prevent this is to setup your cameras such that the person starts and ends within the cameras at all time. https://www.youtube.com/watch?v=LPHeq7bxP38

We don't currently have an option to reprocess in the web app, but if you are able to setup processing locally: https://github.com/stanfordnmbl/opencap ... ne-locally.

Then you can change how many cameras are used https://github.com/stanfordnmbl/opencap ... ics.py#L91 and https://github.com/stanfordnmbl/opencap ... cs.py#L156.

Hope this helps,
Matt