[ros-users] Firewire camera synchronization

[Thomas Moulard]

On Fri, Dec 3, 2010 at 2:54 AM, Jack O'Quin <jack.oquin at gmail.com> wrote:
> On Thu, Dec 2, 2010 at 3:41 PM, Thomas Moulard <thomas.moulard at gmail.com> wrote:
>
>> From the Flea2 documentation:
>> « Automatic Synchronization
>> Multiple Flea2 cameras networked on the same IEEE-1394 bus are
>> automatically synchronized to within 125µs (maximum deviation)
>> of each other, and can synchronize across buses using Point Grey
>> MultiSyncTM software. »
>>
>> http://www.ptgrey.com/products/flea2/index.asp
>>
>> There is nothing in the userland which has to be used to enable the
>> synchronization, it
>> is automatic as long as the acquisition of the two images is done fast
>> enough (which
>> separate process cannot achieve).
>
> Since two cameras on the same bus are synchronized automatically, it
> may just work, even with separate processes.

As long as you synchronize the acquisition with some interprocess locking.
The context switch may also introduce a delay between the two acquisitions.

> Just to see what happens, could you try running two driver nodes each
> connected to a single camera? Capture some images in a bag and check
> the timestamps when they are published. That is easy to do with
> "rxbag".

They are close but not identical (nsec are different).
-- 
Thomas Moulard
http://www.linkedin.com/in/moulard