CCTV

Analogue Cameras

Analogue photography is a commonly used term for photography that uses a progressively changing recording medium, which may be either chemical process based (e.g., photographic film or plate) or electronic (e.g. CCD sensor).

Analogue Video - The original video recording method which stores continuous waves of red, green and blue intensities. In analogue video, the number of rows is fixed. There are no real columns, and the maximum detail is determined by the frequency response of the analogue system.

In a video camera or digital still camera, the signal is captured with a video camera tube or charge coupled device sensor, which sends the picture to be processed by the camera's electronics. The signal can be transmitted or recorded on a storage device for later playback.

Analogue signals can be converted into a digital signal to enable the recordings to be stored on a PC as digital recordings. In this instance the analogue video camera must be plugged directly into a video capture card in a computer, and the card then converts the analogue signal to digital.

Another way to store recordings on a non-analogue media is through the use of a digital video recorder (DVR). Such a device is similar in functionality to a PC with a capture card and appropriate video recording software. Unlike PCs, most DVRs designed for CCTV purposes are embedded devices that require less maintenance and simpler setup than a PC-based solution, for a medium to large number of analogue cameras.

Some DVRs also allow digital broadcasting of the video signal, thus acting like a network camera. If a device does allow broadcasting of the video, but does not record it, then it's called a video server. These devices effectively turn any analogue camera (or any analogue video signal) into a network TV.

IP Cameras

An Internet protocol camera, or IP camera, is a networked digital video camera that transmits data over a Fast Ethernet link. IP cameras (also called "network cameras") are most often used for IP surveillance, a digitized and networked version of closed-circuit television (CCTV).

Benefits of IP camera over analogue technology include:

  • Remote administration from any location.
  • Digital zoom.
  • The ability to easily send images and video anywhere with an Internet connection.
  • Progressive scanning, which enables better quality images extracted from the video, especially for moving targets.
  • Adjustable frame rates and resolution to meet specific needs.
  • Two-way communication.
  • The ability to send alerts if suspicious activity is detected.
  • Lower cabling requirements.
  • Support for intelligent video.

Disadvantages of IP surveillance include greater complexity and bandwidth demands. One alternative for organizations with substantial investment in analog technology is to use a video server to, in effect, turn analog CCTV cameras to IP cameras. A video server is a small standalone server that converts analog signals to a digital format and provides the analog cameras with IP addresses.

Nevertheless, because it offers much more sophisticated capabilities, IP surveillance is increasingly replacing analog CCTV.

Access Control

Biometric Access Control

Biometrics (or biometric authentication) consists of methods for uniquely recognising humans based on one or more intrinsic physical or behavioral trait. In computer science, in particular, biometrics is used as a form of identity access management and access control. It is also used to identify individuals in groups that are under surveillance.

Biometric identifiers are the distinctive, measurable characteristics used to identify individuals. The two categories of biometric identifiers include physiological and behavioral characteristics. Physiological characteristics are related to the shape of the body, and include but are not limited to: fingerprint, face recognition, DNA, palm print, hand geometry and iris recognition (which has largely replaced retina).