The Security Labs customer support staff welcomes your call regarding specifications, operation, or the installation of any of our products. We can talk to you about your general requirements and answer questions regarding integration of any current equipment you may have. If you are new to video surveillance, we are eager to explain the benefits of CCTV and explore your questions.
 
Customer Support 1-800-774-028
CCTV Glossary
  • Audio Recording : Most closed circuit television recorders have an audio input which allows them to record or listen to live audio. Due to privacy concerns, most security cameras do not have built-in microphones so in order to record audio; a separate microphone would be required. In many cases, audio recording is illegal if you are recording private conversations without consent or knowledge; therefore it is best to consult your local officials to determine legality before setting up an audio recording system.
  • AGC : Automatic Gain Control. This feature makes adjustment for lighting changes such as bright reflections from glass or headlights passing through the image to provide a more balanced lighting level. AGC reduces signal to noise ratio so that a higher quality recording can be achieved even in harsh lighting conditions.
  • Back Light Compensation (BLC) : Refers to the electronic processing of video signals that can reduce the darkness and shadowing effects caused by strong lighting in the target area. Back light compensation can increase the brightness of objects in the picture that would normally appear dark as a result of strong lighting in the background.
  • BNC: The standard RF signal connector for coaxial video cables used in security applications. BNC connectors use a bayonet type locking system with two protruding posts on the female end, while the male end has a rotating sleeve, which slides over the posts then twists a quarter turn to lock tightly.
  • Category 5 Cable : Twisted pair cable that is capable of data speeds up to 100 megabits per second. Cat-5 Cable is typically used for computer networking and video transmission/distribution systems.
  • CCD: Charge-coupled device is an electronic capacitor array or a photosensitive image device that captures the light that passes through a camera lens and transforms it into an electrical charge that captures a two dimensional image of the scene projected onto it. Light passes through the iris, is focused by the lens, and lands on the CCD where the image is generated.
  • CCTV : Closed Circuit Television. This references a television/camera system which does not openly transmit or broadcast an image, but rather directly transmits the video signal to a specific place. The increasing use of CCTV has allowed people to purchase and install CCTV systems for personal, private or commercial use.
  • Codec: A Codec is a device or computer program capable of encoding and or decoding a digital data stream such as video from a security camera. Video images can generate very large file sizes so manufacturers use Codecs to compress video files to make them smaller and easier to work with. The same video codec is then used to view the compressed video when you call up any recorded or archived footage.  .
  • Compact Flash : A removable storage media that can store images and video clips on a small electronic card that can be erased and re-formatted.
  • Covert Camera : A CCTV camera disguised as another device such as a clock radio, picture frame or a motion detector.
  • Digital Video Recorder (DVR): A video recording device that records images to hard disk drives or other digital recording media such as a CD, DVD or Flash Memory card.
  • Frame Rate: Frame rate refers to the speed at which still images or pictures are recorded in a 1-second period. Real time video is considered to be approximately 30 images per second, but most surveillance system recorders reduce that rate to save disk space and processing power. The more frames that are recorded each second, the more smooth and fluid the playback will be.
  • H.264 Compression: H.264 is a very high quality video codec. The H.264 codec provides superior video quality with much lower file sizes. Without compromising image quality, H.264 video compression can reduce the size of a digital video file by more than 80% compared with the Motion JPEG format and as much as 50% more than with the traditional MPEG-4 standard.
  • Infrared Illuminator: A light or series of light emitting diodes that are used to allow security cameras to see in total darkness. Infrared light is used to augment the available ambient light and it is normally invisible to the human eye, but can be picked up by security cameras.
  • JPEG: JPEG is a commonly used method of video compression for photographic and video images. JPEG allows the degree of compression to be adjusted to provide a balance between storage size and image quality. JPEG compression can achieve 10:1 compression with no perceptible loss in image quality. JPEG is an acronym for the committee that created the compression format, the Joint Photographic Experts Group (JPEG).
  • LAN: Local Area Network, a network that provides a connection to multiple computers within a small area such as a home or an office.
  • LCD : A Liquid Crystal Display monitor. LCD monitors re thin flat panel monitors that have lower power requirements and are much thinner and lighter than CRT based monitors.
  • LED: An LED (Light Emitting Diode) is a small electronic diode that emits light when an electrical charge is applied. LED’s are widely used as indicator lights on electronic devices and they are also used to provide area lighting for infrared night-vision cameras.
  • Lux: Lux is a measurement of light intensity and it is often used to refer to the lighting level required for a security camera to provide usable images. Low-Light cameras can often see in lighting conditions ranging from .01 to .1 lux, while standard security cameras require 1 lux or more to operate. 1 lux is equivalent to the light provided by a full moon at night.
  • Motion Detection: Motion detection is a common trigger for cameras to begin or stop recording. Many modern digital video recorders support digital video motion detection where the video is analyzed for motion or changes in pixels. When enough of a change occurs, the system begins recording video to the hard drive. By recording video only when motion occurs, a user can save hard drive space by not recording ‘empty’ times when nothing is happening. External motion detectors can also be used to trigger recording when they are tied into a DVR and programmed as an alarm input. This method is more reliable for high security applications because motion detectors are less susceptible to false alarms.
  • Megabyte (MB) : A measurement of the size of computer storage. A megabyte is equal to 1,000,000 bytes or 1024 kilobytes and it is commonly referred to as MB. A Gigabyte equals 1,000 Megabytes. A Terabyte equals 1,000 Gigabytes.
  • MPEG: MPEG is a commonly used method of video compression for video images. MPEG allows the degree of compression to be adjusted to provide a balance between storage size and image quality. MPEG compression consists of 4 different parts, MPEG-1, MPEG-2, MPEG-3 and MPEG-4. MPEG is an acronym for the committee that created the compression format, the Moving Picture Experts Group (MPEG).
  • Pan, Tilt, Zoom (PTZ) : A reference to a feature of moveable security cameras wherein pan refers to the ability for horizontal movement, panning refers to vertical movement and zooming refers to the ability of the camera lens to vary its focal length. PTZ security cameras may be controlled with a matrix switcher, a multiplexer, a digital video recorder or with a joystick controller unit.
  • Quad : A device that allows four video surveillance cameras to be displayed and recorded simultaneously. A quad is normally used with a time lapse video recorder to allow multi-camera recording on a single video tape.
  • Resolution : A measure of a security camera or a video monitors ability to reproduce detail which is equal to the total amount of lines that appears on the screen. Most computer screens are measured by both width and height (IE : 1024 lines wide, 768 lines tall) while most cameras are measured by TVL (Television Lines), or height alone
  • Router: A device that acts as a bridge to handle different protocols and allow several devices to communicate and exchange information on a private network. Commonly used to split up an Internet connection among multiple computers, a router can cause difficulties when viewing cameras remotely. To properly view cameras from a remote location through a router, port forwarding is needed to view the images.
  • Simplex: In CCTV systems, the term simplex refers to the ability to perform one multiplexing function at a time, such as playback, recording, or remote viewing.
  • Static IP Address: An IP address that remains the same each time your computer or a router connects to the Internet. Especially useful for remote viewing applications because the IP address of the digital video recorder never changes so you can always connect.
  • Triplex: Refers to a device that can perform three functions simultaneously such as live viewing, recording and playback of video all at the same time.
  • Twisted Pair : A cable composed of two smaller cables twisted together. Twisted pair wire is often used for powering cameras or for data transmission. Common varieties of twisted pair cable include category 3 telephone cable and category 5 network and data cable. With the use of video baluns, twisted pair cable can be used to transmit security camera video, audio and data over relatively long distances. Also: UTP= Universal Twisted pair. UPT video baluns use twisted pair wiring to send the video signal from the camera to the monitor or DVR. A video blaun is needed at each end of the wire run.
  • USB Drive: A universal serial bus is a removable digital storage device that connects to a USB port of a computer or a DVR. A USB drive can be a fast efficient way to back-up and transfer digital video files from a DVR to a computer.
  • Video Motion Detection: A software feature that analyzes a video stream from a security camera for changes in pixels, which represent motion. Many digital video recorders allow you to create several zones of detection as well as add masking in areas where you do not want to record motion, such as a busy street, or a tree moving in the breeze.
  • Wide Area Network (WAN): Wide Area Network is a term used to describe a network that spans large distances. Commonly used when connecting multiple buildings together between cities or even states. Any computer network that covers a broad area can be considered a WAN, including the Internet.
  • Weatherproof/resistant: This term is used to describe a camera or housing designed to be placed in an outside environment where it may be subjected to rain, snow, wind, and other common outdoor conditions.
  • Waterproof: A camera designed to be submerged in water. Most weatherproof cameras are NOT waterproof and many waterproof cameras may not be recommended for use in certain outdoor situations such as extreme heat or cold.
  • Web Server: A device capable of hosting a web page in the HTML format (Hyper Text Markup Language) so that it can be viewed on a computer web browser. Web servers will typically host a web page that contains streaming video from a DVR or camera.
  • Zoom Lens : A type of optical lens that can change its focal length and zoom in or out to bring a distant object into a closer view. Some security cameras offer both an electronic zoom and an auto-focus feature which automatically adjusts the focus based on objects in the frame. Most high end PTZ dome cameras offer zoom with auto-focus.
  • Zoom Ratio : A number used to describe how far a camera can zoom in on an object. Based on its widest angle, such as 5-mm, an 18x lens can zoom out to 90-mm. In simpler terms, an 18x zoom lens can magnify an object in the distance eighteen times. Many high end cameras have an optical zoom and a digital zoom for even further viewing.
 
Why choose a digital recorder?
During the last decade, microprocessor based (digital) technology has made major advances. Processors, hard drives, and computer memory are continuing to increase in speed and ability. In the surveillance industry, these advances have made it possible for recording digital video. A Digital Video Recorder (DVR) retrieves the video from a security camera, multiplexer, or other source, and converts the signal from analog to digital. The digitized video data is then compressed and stored on the DVR’s hard drive. Video compression (making the data size smaller) allows the digitized video to be stored efficiently. The process of storing the video data on the DVR hard drive is similar to the way your desk top computer stores a word processor or other data file. The file (video image) is ‘marked’ when stored so the user has quick access to it at a later time. Because the DVR operates like a computer, retrieval of data (video) is very fast. A search by event, time and date, or by camera, happens almost instantaneously. The resolution (image size) and quality (amount of compression) are features that can be set by the user and determine how large and how detailed the playback image is on the monitor. Setting the image for full screen playback with optimum detail requires the most data space on the hard drive and will lower the number of hours of video that can be stored before the hard drive is full. An “overwrite when full” feature assures the user that should the hard drive become full, the DVR will continue to record by writing over the oldest video first. Like time lapse recorders, DVRs can be set to record at different frame rates. The fastest any DVR or time lapse can record is 60 fields (images) per second. Setting the recorder to a much slower setting, for example, one image every 8 seconds, will greatly extend the total recording time. Like time lapse recorders, DVRs can also be set to event record when triggered by an external trigger such as a door contact, or by a preprogrammed schedule. Adjusting the DVR for the appropriate frame rate, image size, and compression is simplified with on screen menus. Advanced features (some models) allow you to connect to the DVR though the TCP/IP protocol in your desktop or laptop computer. The DVR can be connected to your office’s local area network (LAN) and cameras can be viewed at your PC monitor. If your LAN is connected to a broadband internet connection (DSL or cable), the DVR connected to the LAN can be viewed from home via the internet.
 
How does IR work?
The human eye can see in the visible light portion of the spectrum chart (below). Above visible light is infrared (IR). The CCD or CMOS device inside your security camera can detect IR light and use it to help illuminate the area viewed. Many Security Labs cameras emit IR so that the area in front of the camera can be seen in total darkness. ONLY black and white (B/W) cameras are affected by IR illumination. Color cameras will detect IR to a much lesser degree. Take your TV remote and press a button while pointing it at your camera for a simple demonstration of how a CCTV camera can see IR.
 
 
spectrum_thumb.jpg (46485 bytes)
 
How much will the security camera see?
The field of view (FOV) is based on the camera & lens. Security Labs cameras are supplied with a wide angle view lens. Wide angle lenses are suitable for most applications due to their ability to view a large area. A 4mm wide angle lens will be able to view an area 20’ high x 26’ wide at 21’ away. As an example, a 15’ x 15’ room is shown in the diagram below. Observe that the 4mm lens (green arrows) allows better wide angle viewing coverage than the 12mm lens (red arrows). In applications where a closer view is needed (such as above a cash register or over a greater distance), an 8 or 12mm may be desired. The same camera (above) at 21’ away with a 8mm lens will have a 10’ vertical x 13’ horizontal FOV. At 21’ with a 12mm lens, the FOV will be approx 6’ vertical x 9’ horizontal. Increasing the focal length of the lens decreases the perceived distance to the viewing area. The SLC-110, SLC115, SLC-120, and SLC-1041 cameras have interchangeable lenses available in 8 and 12mm. See the FOV diagram below for approximate views with different focal length lenses.

FOV copy.jpg (103552 bytes)