Autonomous drones for surveillance are not commercially available yet.
However, RPAS (remotely piloted aerial systems) drones are nowadays being used with increasing frequency for human piloted surveillance of large areas. An example is guarding railroad tracks for copper theft and vandalism, for which both the Belgian as well as the German railroad companies are investigating the utilization of drones.
With the OmniDrone results, these surveillance tasks can be done much more thoroughly (because of the omnidirectional field-of-view), in real-time, and with less personnel involved (e.g. one operator for multiple UAVs).