Digital video surveillance cameras may be classified as SDI (serial digital interface) or IP (Internet protocol). SDI cameras transmit uncompressed video using the SMPTE standard. HD-SDI cameras are able to transmit uncompressed 1080p video. SDI cameras require a dedicated server where video content is processed and compressed.
IP cameras have their own CPU and memory. The video signal is processed and compressed in the camera using JPEG2000 or H.264 standards. Then the compressed signal is transmitted using LAN or Internet. IP cameras may not need a central server since part of server’s function may be already implemented in the camera.
Some cameras are wired, and others wireless and do not need a cable connection between camera and server. Wireless cameras are usually based on IP technology.
There are many different types of digital surveillance cameras for a wide variety of applications:
- Static security cameras are dedicated to observing some particular surveillance area. Examples are box or bullet cameras.
- Bullet security cameras (cylinder cameras) are wall-mounted or ceiling-mountedcylinder shape cameras. They are generally easy to mount and adjust, and they may be waterproof.
- Box cameras do not come with a lens. The user can select from a wide variety of lenses. Lenses are usually big to direct more light to the sensor, thereby increasing video quality.
- Discreet cameras have a shape and size that allows them to be hidden.
- Pan-tilt-zoom (PTZ) security cameras can be moved to cover a larger area using fewer cameras. They can be precisely positioned and their lenses adjusted to magnify and focus on distant objects.
- Night vision cameras can see an area in low light conditions.
- Wide dynamic range cameras can adapt to various lighting conditions.
- Varifocal lens cameras have a lens with variable focal length.
- License plate cameras are able to record clear images of a vehicle’s license plate as it enters or exits a given area.