Back focus : A mechanical adjustment in a camera that moves the imaging device relative to the lens to compensate for different focal lengths of lenses. This is important when a zoom lens is installed.
Back-up Device : This is a generic term used to describe any device used to extract video from a DVR. You could back up files to any connected device such as: a server on a network, an external hard drive, a thumb drive/flash drive or a CD/DVD.
Balun : (Video balun): This is a device that allows video to travel over twisted pair wire (rather than coax RJ59 cable). This device matches the impedances of the different signals. Balun stands for balanced-unbalanced. A balun is required at the camera and at the receiving device (DVR, monitor, etc.). Baluns can be passive or active (with amplification). Passive distance can be up to 1,000 ft. Active can be up to 3,000 or more. Count on less than half that distance with a DVR.
Bandwidth : Device bandwidth is the range of signal frequencies that a piece of audio or video equipment can encode or decode (the operating frequency). Video uses a wider/higher frequency range than audio, thus requires a wider bandwidth.
Bandwidth (Network) : In computer networks the bandwidth is a function of the network design. A typical LAN (leg) within a network has a maximum bandwidth based on the hardware installed. 100Mbps is common. Gigabit network switches are becoming more common. All devices on the network share the total available bandwidth. Devices that take up a large percentage of the available bandwidth (like video) are a concern to systems administrators.
Bandwidth limiter: This refers to a feature in some DVRs and Remote Software that limits the size of the network traffic provided. This feature restricts DVR/Remote software communication so more bandwidth remains available for other network traffic.
Barcode : A series of coded lines that contain encoded information. Example: The UPC code (Universal Product Code) is standard on all products sold in supermarkets.
Base Band Video : This is the video signal used in CCTV. It is the NTSC or PAL format minus the broadcast frequency modulation and many other embedded signals used in Broadcast TV. It consists of video, horizontal sync and vertical sync. This is all that is required to view a video signal on a monitor.
Beta Test : This refers to initial testing of a newly developed product that is ready to ship. Terminology differs between manufacturers. Usually by this stage major bugs that would stop shipment of the product are less likely than in the alpha test stage.
Biometrics : In CCTV biometrics refers to the hardware/software used to recognize body parts as a method of individual identification. Biometric readers can scan and identify finger prints, Iris and Retinas. Facial recognition is another biometric recognition that comes under the category of video analytics.
Bit Rate : Bit rate is measured in bits per second. In IP video it usually refers to the bit rate from an IP camera. Controlling the bit rate controls the bandwidth needed to transfer data from the camera. The camera processor will automatically limit the maximum bit rate sent from the camera to the bit rate setting selected.
Bits : Individual parts of data communication. A bit is the smallest part of the overall data stream. Serial communication is measured in bits per second (RS-232, RS-485, etc.).
Black Pixels : This refers to hidden (unseen) pixels when megapixel cameras produce more pixels than can be seen on the monitor used for display. This is an issue as cameras usually lead the pixel count charge. Monitors can’t display all the pixels available and must “scale” the image (remove/rearrange pixels) to accommodate the display capability. Although you may be paying for more pixels than you can normally display, there is good news when you zoom in on a megapixel image. Those black (hidden) pixels can now be used in the expanded portion of the image providing the same quality level with expanded images. This avoids the fuzzy look produced by standard resolution zoomed images
BNC : This is the standard connector type used in CCTV. It provides an easy snap-on connection for a coax cable. What BNC stands for is less clear. Some say it means British Naval Connector. Others attribute it to the type and the inventor; Bayonet Neil Councilman.
Browser : In video most manufacturers recommend Internet Explorer as the browser connection for their products. You can access DVR, NVR and IP cameras just by entering the IP address in the browser command line.
Browser Based DVR Remote Software : Browser based programs can allow anyone to connect to the DVR as long as they have the site name and the logon information (user name and password). You don’t have to physically have the program on disk. Once you connect to the DVR site using your Internet browser (like Internet Explorer) the DVR sends you all the information you need. So the remote program is resident in the DVR (the server site) and the Browser user is the remote client. The program is downloaded from the server (DVR) to the client (remote user’s PC).
Burn Rate : This refers to the required storage for recorded information. The burn-rate is the maximum storage needed to record for one hour. Once you know this number you can size the system by simply multiplying the burn-rate by the number of hours the customer needs to keep the data. (GB/hr. = Avg. image size, x # of images/sec, x # of cameras, x 60 [sec] x 60 [minutes]).
Bytes : A byte is typically a series of eight bits. This is enough information to represent a single alphanumeric character. Parallel communication is measured in bytes (memory sizes, hard drive sizes, etc.).