We log impressions to ensure ads are being delivered.
Our units report to our cloud servers every few minutes. They check to see if there are any new campaigns to load. They also send back impression counts for each slide they show.
Exposure is measured the same way as billboards by counting traffic. We get the number of customers or pedestrians in the area to estimate exposure.
The algorithm distributes the impressions across all the active screens that you select. It shows each ad at least every 3 minutes. We measure the traffic for each location.