[ipython]

The distributed part is the clocks on the cameras across the world. The article discusses the timestamp is included in the exif data embedded in the jpeg file.

The clocks are most likely synchronized based on gps assuming they’re already pulling location data from the satellites, the time is “free”. However, the precision of the clocks is not specified and like any process is subject to error. So at the small timeframes here (sub millisecond), you are potentially within the margin of error. When the error bars of several measurements from distributed parts of your system overlap, how do you determine an ordering between them?

[ezconnect]

Whoever arrives first? Since they can't arrive at the same time because of sequential processing at the final step. So the guy who implemented the system will be the arbiter of truth.