Passive IR sensor detects movement of a human body in a certain section at an acute angle of 9 to 12 degrees through a Fresnel lens. 

Panoramic Camera records videos without distortion by installing one or more cameras on one body to obtain an image in front, and is also called Multi sensor Camera. 

PTZ Camera freely moves up, down, left, and right by optical zoom and mechanism of a lens to photograph a subject. 

On-premise a method of installing and operating directly on a computer room server owned by itself. The disadvantage is that it takes a lot of time and money to build a system. 

Network Video Recorder is an equipment for recording, monitoring, event management, and playback of a network-based IP camera or server.