CCTV and access control

After a break-in the owner reviews the footage and sees a silhouette at the entrance, with no face and no number plate. The camera was mounted high and wide to cover the whole yard, so the person took up only a few dozen pixels of the frame. At night the infrared light bounced off a nearby wall and washed out the picture.

Each camera first gets a task based on EN 62676-4, a standard that describes levels from detection to identification in terms of pixel density. Recognising a known person takes about 125 pixels per metre, identifying a stranger takes 250. The focal length, mounting height and distance follow from that.

• IP cameras powered over PoE (IEEE 802.3af/at), one cable for power and data
• WDR for entrances with strong light behind the person
• recording to a local NVR in H.265, which takes roughly half the space of H.264
• cameras on a separate network, with no direct access from the internet

CCTV records personal data, so the General Data Protection Regulation and the Croatian act implementing it both apply. In practice this means the purpose of the surveillance has to be defined, usually protecting people and property, the entrance to a monitored area has to carry a visible sign, and footage is kept only as long as that purpose requires and then deleted automatically. Only an authorised person has access to the recordings.

We aim cameras so they do not cover public space, the neighbour's yard or someone else's front door. Monitoring a workplace brings extra rules towards employees, so check retention periods and notice obligations with whoever handles data protection for you. We set up the technical side: automatic deletion, user roles and a log of who viewed the footage.