It is the process of watching over a facility which is under suspicion or area to be secured; main part of the surveillance electronic security system consists of camera or CCTV cameras which forms as eyes to surveillance system. System consists of different kinds of equipment which helps in visualizing and saving of recorded surveillance data. The close-circuits IP cameras and CCTVS transfers image information to a remote access place. The main feature of this system is that, it can use any place where we watch the human being actions. Some of the CCTV surveillance systems are cameras, network equipments, IP cameras and monitors. In this system, we can detect the crime through the camera, the alarm rings after receiving the signal from the cameras which are connected CCTV system; to concern on the detection of interruption or suspicion occurrence on a protected area or capability, the complete operation is based on the CCTV surveillance system through internet. The figure below is representing the CCTV Surveillance Systems.
NVR vs DVR
The difference between an NVR and DVR can be confusing to many. A network video recorder (NVR) records IP cameras that are transmitted via a network cable. These cameras connect to an NVR either by way of a network switch or router and in some cases directly to the recorder itself. In essence, NVRs record IP cameras. Digital video recorders (DVRs) are synonymous with recording analog or coax based cameras. Newer HD-SDI or HD-CVI cameras also transmit via coax cable and also use DVRs to record. So in short, a DVR records cameras that are connected via a coax cable. There are more technical details involved explaining the two technologies but for the purpose of this article we will keep it as simple as possible. They both record cameras and offer the same similar options but they record different transmission methods.
IP CAMERA
An Internet protocol camera, or IP camera, is a type of digital video camera commonly employed for surveillance, and which, unlike analog closed circuit television (CCTV) cameras, can send and receive data via a computer network and the Internet. Although most cameras that do this are webcams, the term "IP camera" or "netcam" is usually applied only to those used for surveillance. The first centralized IP camera was Axis Neteye 200, released in 1996 by Axis Communications.
There are two kinds of IP cameras:
Centralized IP cameras, which require a central network video recorder (NVR) to handle the recording, video and alarm management.
Decentralized IP cameras, which do not require a central NVR, as the cameras have recording function built-in and can thus record directly to any standard storage media, such as SD cards, NAS (network-attached storage) or a PC/server.