CCTV System How its works :

Closed-circuit television(CCTV) is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted, though it may employ point to point (P2P), point to multipoint, or mesh wireless links.

Why used CCTV 

  • Reduce Cost and Risk.

  • Prevent and Deter Crime.

  • Fool-Proof Coverage.

  • Reduce Property Insurance Premiums.

  • Increase Customer’s confidence.

  • Easy to implement.

  • Keep Your Employees Honest.

  • Encourage Good Behavior.

  • Prevent Safety Incidents.

Application of CCTV system.

  • Maintaining security in restricted or secure areas such as homes and financial institutions among others

  • Monitoring traffic

  • Building and ground security

  • Observing behavior of people within a given setting such as workplace, prisons or hospitals.

  • Crime prevention and detection

  • Number plate recording.

  • Public Spaces and other Large Areas

  • Football and cricket stadiums

  • Vending machines

  • Warehouse CCTV




Elements of CCTV system.

  • Camera

  • Lens

  • Monitor unit

  • DVR / NVR

  • Cable (Coaxial / Ethernet)

  • Storage devices

  • DC power supply (12V)

Types of CCTV Systems

Analog CCTV system:

  • Analog security cameras capture an analog video signal and transfer that signal over coax cable to the Digital Video Recorder (DVR). Each camera may be powered by plugging in the power supply right at the camera or by using RG59 Siamese cable which bundles the video and the power cables.
  • Requires an DVR to capture image.

Digital / IP CCTV system :

  • IP stands for Internet Protocol, and basically refers to a digital video camera that can send and receive data via a computer network.
  • Requires a NVR to capture image.

CCTV  system Block Diagram:

 

How CCTV Camera Works 

 

A camera lens takes all the light rays bouncing around and uses glass to redirect them to a single point, creating a sharp image. … When all of those light rays meet back together on a digital camera sensor or a piece of film, they create a sharp image




CCTV Camera Types :

CCTV cameras are being installed every where for purpose of security and crime prevention and detection. There are many type if CCTV cameras are available for this purpose.

  • Wireless Camera

  • Indoor Camera

  • Outdoor camera

  • IR day/Night Camera

  • Dome Camera

  • IR Bullet Camera

  • Vandal Proof Camera

  • Hidden Camera

  • Pen Tilt Zoom (PTZ) Camera

  • Explosion proof FLP Camera

  • Panoramic camera




Wireless Camera:-

  • Wireless security cameras are closed-circuit television (CCTV) cameras that transmit a video and audio signal to a wireless receiver through a radio band. Many wireless security cameras require at least one cable or wire for power; “wireless” refers to the transmission of video/audio. However, some wireless security cameras are battery-powered, making the cameras truly wireless from top to bottom.

    Wireless cameras are proving very popular among modern security consumers due to their low installation costs (there is no need to run expensive video extension cables) and flexible mounting options; wireless cameras can be mounted/installed in locations previously unavailable to standard wired cameras. In addition to the ease of use and convenience of access, wireless security camera allows users to leverage broadband wireless internet to provide seamless video streaming over-internet.

Indoor Camera:-

  • Indoor camera as its name suggests used for indoor security mechanism.
  • These are suitable for security in homes, schools, offices, hotels etc…

Outdoor Camera:-

  • Outdoor camera is used for outdoor places.
  • They are mostly used for entry and exist points with limited night lighting.
  • These cameras have hard Shell vandal-proof casings.

IR day/Night Camera:-

  • IR day/night cameras are used for high alert security areas were surveillance needs to happened day and night.
  • These cameras are used by military personal, in parking lots and high security zones.
  • The cameras are ideal for outdoor surveillance applications.

Dome Camera:-

  • The popularity of these cameras is driven by three major reasons, namely:
  • Easy installation -MostDome Camerasrequire only two or more screws to install. In addition, they can easily be mounted on both horizontal and vertical surfaces such as walls and ceilings.
  • Vandal-proof feature: The dome-shaped, hardened plastic casing that covers the camera protects it from vandalism.
  • Infrared Capability: Some of theDome Camerascome fitted with IR illuminators, which enable the cameras to capture video images in low lighting conditions.
  • Dome Cameras are the most commonly used for indoor security and surveillance applications.
  • Dome is not always a weatherproof camera so these are not suited for outside peripherals.

IR Bullet Camera:-

  • When the lights are extremely low or pitch dark
  • When the camera is not within someone’s reach the distance infrared can see are based upon its illumination capacity. Infrared have LED which cast out into the darkness. the camera has LED which cast out into darkness.
  • The biggest disadvantage of Infrared led do have a limited life and led burns out in some time.
  • Whenever an infrared led is illuminated it turns the picture to black and white hence reducing the ability of recognition.
  • These came to have an advantage of in build IP 66 rated housing and comes withstand.

Vandal Camera:-

  • Vandal-resistant  cameras are housed in sturdy metal enclosures with tamper resistant fasteners. Because vandals are unable to destroy or tamper with the security cameras, they provide constant coverage.  cameras come with camera tamper detection analytics that detect if the video is grossly changed, such as when a camera is spray painted, covered or moved.
  • Vandal-resistant cameras are designed to be rugged and tough so that they will continue working when subjected to rough treatment. The best vandal-resistant cameras will withstand direct blows to their housings and lens covers without breaking and without interrupting the video. Vandals will also find it next-to-impossible to open the camera’s housing to do damage or make any kind of alteration.
  • Keeping people and property safe are high priorities for governments, businesses and schools. Criminals will try to disable video cameras by striking them with heavy objects or attempting to pry them open to damage or cover the lens. Pelco high-security cameras are designed to handle abuse and they are rated IK10 vandal-resistant.

Hidden Camera:-

  • A hidden camera also known as a spy camera is a still or video camera used to record people without their knowledge.
  • The term “hidden camera” is commonly used in TV shows, sometimes when subjects are unaware that they are being recorded, and usually lacking their knowledge and consent.
  • The term “spy camera” is generally used when the subject would normally be expected to object to being recorded as an invasion of their privacy. The term “security camera” is commonly used to provide a justification for a surreptitious recording, and can be contrasted with security camera, which is visible and which sometimes is accompanied with a warning notice of its presence.
  • The camera may be “hidden” because it is not visible to the subject being filmed, or is disguised as another object. Such a camera may not be visible to the subject, for example, because it is fitted with a long-focus lens and located beyond the view of the subject, or located, say, behind a two-way mirror. Hidden cameras can be built into commonly used objects such as television sets, smoke detectors, alarm clocks, motion detectors, ink pen caps, plants, and mobile phones.
  • Hidden cameras may be used for household surveillance devices and may also be used commercially or industrially as spying. The proliferation and lower costs of video recording devices have led to an increase in the use of hidden cameras for legitimate surveillance need, as well as for entertainment and other purposes.

Pen Tilt-Zoom  PTZ Camera:-

PTZ camera are to be considered when
  • Best suited for patrol duty and open area application –Like border, Airport, Parking lot etc.
  • When we want live control of the camera and adjusting the manual pan, tilt or zoom on a fixed camera is not practical.
  • When a tour of the premises is required.
  • When several angle is required to be viewed from a single camera.
  • The cost of a PTZ camera can varies 5-10 times of a fixed camera.
  • PTZ camera cannot see or record area where it is not looking.

Explosion-proof FLP Camera:-

  • Explosion-proof IP PTZ Camera is fully-developed and specially designed for use in flammable and explosive hazardous areas.
  • The system uses 316 stainless steel to ensure its good explosion-proof performance in hazardous areas. It has an absolute operating temperature range of -40°F~140°F (-40°C~60°C )
  • This camera is properly sealed to prevent the intake of flammable dust and ensure strong corrosion-resistant capabilities.
  • It can be used Division 1 and 2 hazardous locations where fire or explosion hazards may exist due to the presence of flammable gases or vapors (Gas Groups: II A, II B, II C; Temperature Classes: T1-T6); For zone 21 and 22 hazardous locations where combustible dust clouds may occur.
  • Explosion-proof cameras available both categories i.e box  type and  PTZ camera .
  • The cost of the camera approximately more that box type           $ 2000 and FLP PTZ camera cost around $4500.

Panoramic Camera 360:-

  • Panoramic cameras give you wide-area coverage with just one camera. You can use them to monitor activities and detect incidents in large areas, track the flow of people, and improve area management. And because just one camera plays the role of many, your installation and system costs are kept lower.
  • Designed for real-time monitoring, these cameras provide both an extremely high level of detail in the direction of your choice together with a constant 180 to 360° overview.
  • Multidirectional cameras are well suited for city surveillance applications, such as monitoring public squares, parking lots and other open areas.
  • Mounted Multiple cameras in to a single ring  and attached them into a single processing sysytem.
  • 360 Camera or Ominidirctional camera is a camera or combination of camera with a 360-degree field of view in the horizontal plane, or with a visual field that covers (approximately) the entire sphere. Omnidirectional cameras are important in areas where large visual field coverage is needed, such as in panoramic photography and robotics. • 360 camera captures light from all directions falling onto the focal point, covering a full sphere

CCTV Camera Selection :-

If we select the camera, we will consider these categories
  • Indoor or Outdoor

  • Day / Night Surveillance

  • Lens Selection

  • Camera Form Factor

  • Video Codec

  • Motion Detection

  • POE (Only for IP) / Power source

  • Wireless / Wiring

  • Viewing

CCTV Camera lens Selection:-

There are two types of lens Fixed and varifocal

Fixed lens :

Fixed lens are those lenses Where lens size doesn’t change, all we can do is focus, we cant zoom in or zoom out Common sizes are 12mm, 08mm,06mm,04mm,3.6mm,2.8mm,  

Varifocal Lens :-

In Varifocal lens size can be changed during the installation process & Zoom in and Zoom out is possible. Common Sizes available are 2.5mm~8mm, 3.0mm~12mm, 5.0mm~50mm

Compare different lens , view angle,s, and cover  distance.

Size of lens 2.5 mm , 2.8 mm , 3.6 mm , 4 mm , 6 mm, 8 mm , 12 mm , 16 mm , 25 mm and 60 mm

Focal length Adjustment of lens :-

Focal length can be adjusted by 3 methods:

Manual Mode (No Cable) :- 

To be used only indoors and where the lighting condition is always the same.

Auto Iris (With a Cable) :-

Adjusts automatically to allow more or less light to be received by the CCD Chip in the Camera.

Motor Zoom (With cable and & telemetry receiver is needed) :-

To be found mostly with Pant and Tilt systems, The zoom & Focus can be manually controlled

Video Recorders (DVR/NVR/ WiFi NVR)

  • Video Recorder is at the heart of the CCTV installation. They receive, manage, store and record the video captured by the cameras.
  • Video Recorders are two types DVR -Digital Video Recorder and NVR –Network Video Recorder
  • Not each DVR/NVR is the same. It comes in 4, 8 or 16 channel configurations. Each camera is connected to a channel. So it is important to buy the DVR /NVR with the right number of channels to support all your cameras. DVR / NVRs also vary in terms of recording speeds, compression, storage, and warranty.




 NVR , Wifi NVR and DVR Connection 




Cable used in CCTV :-

Coaxial / Ethernet

  • CCTV can be analog or IP based. Depending on that the cables can be Coaxial cable or CAT5/CAT6 (RJ45) cables also known as Ethernet cables.
  • Cables connect the camera with the DVR /NVR.
  • You can also find Siamese CCTV cables. Siamese cables contain an coaxial cable that connects the camera to the DVR and an 18 gauge 2 conductor power cable that supplies power to the camera from the SMPS power supply.
  • BNC Connectors is used for  Coaxial cables.
  • RJ45 is used for ethernet cables.

CCTV Connection:-

CCTV complete system Connection:-

PTZ Camera Connections 

Compare Analog and IP based camera installation

Analytics Software

  • Video Analytics Software uses mathematical algorithms to monitor, analyze and manage large volumes of video. It digitally analyzes video inputs; transforming them into intelligent data which help in taking decisions.
  • The following analytics can be configure in analytics software 
  • Vehicle Moving – Should activate alarm if it detects vehicles moving in the scene and passing through the alarm mask.  Object Direction may be used to further filter alarms, as well as object speed, object size.
  • Vehicle Parking – Should activate alarm if vehicles are parked in Alarm mask. The length of time field in seconds or minutes may be used to specify how long vehicles are able to park before the alarm.

  • Vehicles Starting to Move – Should activate alarm if it detects a vehicle starting to move, an alarm will sound. Object Direction, Object Speed and Object Size may be used to further filter alarms.

  • People Moving – Similar to the vehicles Moving trigger, but should apply to people.

  • Anything Moving – Similar to the vehicles moving trigger, but should apply to any objects which are moving (people, Vehicles, Unknown)Intrusion detection for perimeter fixed cameras. Tracking of intruder through PTZ camera based on intruder alarm.

  • Camera obstructed/ out of focus – should activate alarm if the field of view is obstructed or goes out of focus.

  • Cord cut –  Will sound alarm if the video signal is lost.

  • Hardware alarm input – Should be able to receive signals from external devices through alarm I/O and act accordingly.

  • Object left Behind – Should sound alarm if objects are discarded, such as bag on a side walk.

  • Object removed – Similar to object left behind trigger, but should apply to objects

 

 




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