for cctv installers
cctv designers
network engineers
physical security
do-it-yourself video surveillance
free online lens calculator
   facebook twitter Youtube Channel  
 
 


 

 

CCTV and Security Camera Glossary: Angle of View, Focal Length, Field of View, Camera Sensor Format

For effective usage of our CCTV design software for camera lens and network bandwidth and HDD space calculation you should understand all following CCTV installation parameters:

Angle of View - The scene angle that a video camera lens can show on the monitor, like Diagonal Angle, Horizontal Angle and Vertical Angle, usually described in degree.

Aspect Ratio - The ratio of the vertical to the horizontal image size; 4:3 is the PAL standard.

BandwidthThe capacity of the transmission medium stated in bits per second or as a frequency. Or, the amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second (bps) or bytes per second.

Bit - Abbreviated with small “b”. Binary Digit. The smallest unit of data in a computer.

bps - Bits Per Second is the unit used for measuring line speed, the number of information units transmitted per second.

Byte - Abbreviated with capital “B”. A unit of data that is eight bits long and is used by most computers to represent a character such as a letter, number or symbol.

Camera format (Sensor Size) - Video camera’s CCD chips format;  1/4″,  1/3″, 2/3″, 1″ etc.

Camera Sensor – Video image sensor. CCD or C-MOS chip.

CCD - Charge Coupled Device. A video image sensor chip.

CCTV (Closed Circuit Television) - Is a Television system that sends a signal to one or more monitors rather than broadcasting over a public network, hence closed-circuit. A standard CCTV system will normally include a CCTV camera (for capturing video), transmitters and receivers (to transfer the video from the source to where it is recorded), a recording system (for video playback), and a monitor (for video monitoring). CCTV systems are primarily used for security purposes inside and outside buildings.

CMOS - Complementary – Metal Oxide Semiconductor. A video image sensor chip that produces much lower quality picture than CCD chip.

DVR - Digital Video Recorder; records video pictures digitally.

Electronic Shutter - Compensates for moderate light changes in indoor applications without the use of auto iris lenses.

Field Of View (FOV) - The width, height or diameter of a scene to be monitored. Field of View usually determined by the focal length of a lens, the sensor format and the distance to the objects.

Focal Length (FL) - The distance from the center of a lens to the focal point (sensor). The longer the focal length, the narrower is the angle of view.

Frame - A whole video image; is composed of two interlaced fields. A CCD chip produces 30 frames per second at NTSC system and 25 frames at PAL.

Gigabyte (GB) – 1024 Megabyte = 1073741824 Bytes

IP - Internet Protocol. A set of rules to send and receive messages at the Internet address level.

IP CCTV (IP Video) - Internet Protocol Closed Circuit Television

Iris - An adjustable opto-mechanical aperture built into a camera that controls the amount of lights coming through the lens.

JPEG - Joint Photographic Experts Group. A graphic image file or a image compression algorithm.

Kilobyte ( Kb) – 1024 Bytes

Kbps - Kilobits per second. A measure of bandwidth.

LAN - Local Area Network. A group of computers and associated devices that share a common communications line.

Megabyte (MB) – Megabyte = 1024 Kilobyte = 1048576 Bytes

Mbps – Megabits per second. A measure of bandwidth.

MPEG - Moving Picture Experts Group. A standard for a digital video & audio compression.

NTSC - National Television System Committee; formulates standards for American colour television system. NTSC system has 525 horizontal scan lines and 30 frames per second.

PAL - Phase Alternating Line system. A colour television system used in Europe, Australia, parts of Africa and the Middle East. It has 625 horizontal scan lines and 25 frames per second.

PanRotating or scanning a camera side ways to view an area in a horizontal direction.

Pan and Tilt - A Camera mounting device that allows movement in both side ways and up or down.

Server - A computer program that provides services to other computer programs in the same or other computers. Or, the computer that a server program runs.

Switcher - A device that allows the video signals from multiple cameras to be displayed on a monitor, or recorded on a VCR one at a time in sequence.

TCP - Transmission Control Protocol. A set of rules to exchange messages with other Internet points at the information packet level.

Web Camera - A CCTV Camera with built-in web server computer.