Line crossing detection monitors video for movement across a virtual line and can trigger an event notification or alarm when the line is crossed in a configured direction. Installers define the virtual tripwire in the camera or recorder interface by drawing a line across a doorway, gate, corridor, or other boundary, then adjusting direction and detection settings to match the scene.

Buyers should compare 4MP, 5MP, and 8MP resolutions, with higher resolutions providing more image detail for reviewing activity near a virtual line. Lens options include fixed 2.8 mm lenses for consistent views and motorized varifocal lenses covering ranges such as 2.7 to 13.5 mm or 2.8 to 12 mm for adjustable framing.

Dome cameras with line crossing detection typically connect to a network video recorder (NVR) over Ethernet, often using Power over Ethernet (PoE) for both network access and power, while compatible models may also record to a local microSD card. Many can send live video, recordings, and line-crossing alerts to a mobile app, and ONVIF support can help integrate them with compatible surveillance platforms, control systems, and broader security networks.

Dome cameras with line crossing detection require an IP network connection and, for Power over Ethernet (PoE) models, an Ethernet cable connected to an active PoE port on a compatible NVR or network switch. Storage can use onboard microSD cards, with many models supporting capacities up to 512 GB, or a compatible NVR for centralized recording.