What is a surveillance system?
A video surveillance system or a closed circuit television as it is also called represents a television system which operated in a closed circuit. The video surveillance system differs from public television which is available to all people owing a television receiver. As a rule, the activity recorded by the video surveillance system is available only to those connected in the closed circuit or have rights to access this equipment from the exterior (such as internet access). The simplest surveillance system consists of a camera and a view storage unit (DVR or capture card) connected to a screen which can render the activity recorded by the video surveillance system. Complex surveillance cameras are composed of a higher number of much more advanced video surveillance cameras, control devices, recording and viewing devices. Although the equipments composing a video surveillance system are more and more diverse, the operating principle is the same.
Elements at the base of the structure of a video surveillance system:
- Image reception devices – represented by video surveillance cameras (analogical or digital) and equipments which allow vertical or horizontal movement of the a video surveillance camera
- The transmission medium of the video signal, which also has two significant components:
2.1. The physical component, represented by signal cables, control, signal amplifiers, etc. These appear both in analogical and digital video surveillance systems
2.2. The software component. This component consists of protocols of transporting information between the video surveillance camera and the recording viewing device (valid for IP cameras). As a rule, the most frequently used component is represented by TCP/IP transport protocol (for transmitting on the internet the activity of the supervised area)
- Recording, control and viewing equipments represent all devices which the user has access to
3.1. DVR stand alone or capture cards
3.2. Special soft for recording and rendering image
3.3. Control devices PTZ equipments
3.4. TV or screen