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3. 1. What is a CCTV System?
A Closed Circuit Television (or CCTV) system is used for
visual (and frequently audio) monitoring and recording
events in a defined area
Generally categorised for the following requirements:
Deter criminal activity
Assist in the detection of crime
To instil confidence in staff/visitors/customers that they
are in a safe and secure area
Provide management intelligence for health & safety or
commercial use
4. 2. CCTV Principles
Basic Components of a CCTV System (Analogue)
Old style system with analogue video recording from
a multiplexer. Usually a maximum of 16 cameras per
system
5. 2. CCTV Principles
Basic Components of a CCTV System (Analogue)
Old style system with analogue video recording through a
quad. A maximum of 4 cameras per system.
6. CCTV Principles
Basic Components of a System (Digital)
New style system using a DVR to digitally record and
playback, usually up to 16 cameras. No multiplexer or quad
is required as the DVR performs these functions, amongst
others.
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10. 2. CCTV Principles
The Camera
CDD Image Sensor (Charged-Coupled Device)
• A group of optical detector integrated circuits
• Light is ‘sensed’ by individual photo-diodes (rows &
columns of which = ‘pixels‘)
• Pixels develop a charge proportional 1/3 inch CCD
to the light level, which are then
processed by the
camera’s electronics
11.
12.
13.
14. There are 3 main types of CCTV camera lens:
- Fixed Focal Length (The focal length of the lens
cannot be altered)
- Varifocal Length (manual zoom length)
- Motorised Zoom (Focal length can be
automatically adjusted using, for example, a
keyboard controller or DVR) >
15. Angle of View
The greater the focal length, the smaller the angle
of view; therefore the image viewed will be larger
16.
17. Iris Control Methods
Auto Iris
Features integral circuitry which will vary the size of
lens aperture according to changes in light
Direct Drive
Lens control circuitry is within the camera, rather
than the lens (Direct Drive specific lenses and
cameras required)
Fixed/Manual Iris
No electronic control over the iris
19. Camera housings are designed to protect the
camera from weather, dust, vandalism, damage,
etc…
Types of Housings :
‘IP rated’
Weather Proof
Vandal Resistant
With or without brackets
With or without internal heaters
Wash & Wipe
20. ‘IP ratings’ are a measure of resistance to the
penetration of solid objects (e.g. dust) and liquids
(e.g. rain!)
A product considered to be ‘weatherproof’ would
have a rating of IP65 and above
-‘IP’ stands for Ingress Protection
- The first number (in this case 6) is
the protection against solids (0~6,
6 being dustproof)
- The second number (in this case 5)
is the protection against liquid
(0~8, 8 being protected gainst
constant submersion )
21. Cameras and housings with heaters will require
power, mains or low voltage depending upon
the product you have chosen.
Where low voltage PSUs are required there are
various choices.
24v AV 500MA up to 4A
12v DC 750MA up to 4A
22. Early CCTV systems used analogue time-lapse
VCRs
CCTV systems now use DVRs (Digital Video
Recorders) with a huge range of benefits over old
analogue technology
Many existing installations, therefore, are
upgrading their recording system from analogue
VCR to DVR
23.
24. The benefits of DVRs:
Digital image quality
No need for tapes (changing / storage of)
Fast, easy image search & retrieval • Remote viewing
& control capabilities
Never stops recording • Up to 400 images per second
(IPS) record rate
Up to 1.5TB storage
Easily providing in excess of 31 days storage
Less mechanical components to service >
25.
26. Main factors for consideration in choosing the
correct DVR:
Number of cameras
Record rate (images per second)
HDD size (amount of data storage)
Remote viewing / control
Fixed / Mobile
Data transfer/storage media formats
27. Choosing recording frame rate:
Each DVR has a maximum IPS rate (100, 200, 400)
The IPS rate is normally divided by the number of
channels ie. 400 IPS, 16 channel recorder would
record @ 25 IPS per camera
High quality DVRs allow control of IPS rate per
camera channel
28. How long does the customer require to retain the
images/video on the DVR?
Record duration is the
‘data lifetime’ of the recorded
images / video on the DVR
Data lifetime will be determined by customer’s
specific requirements and rules of the Data Protection
Act
Longer data lifetimes require larger HDD space
29. Estimating record duration, the following all
Need to be considered:
Number of camera channels
Hard Drive size
IPS rate
Compression type
30. Multiplex (Simultaneous functionality) :
Simplex: The ability to record or playback but not at the
same time. For live view it is only possible to see a single
camera on the monitor, multiple camera view is possible
during playback.
Duplex: The ability to record and playback
simultaneously. Multiple live screen is possible. However,
the monitor will only display live images or recorded
images.
Triplex: The ability to record and playback
simultaneously. Multiple live screen is possible and unlike
Duplex operation the monitor will display both live
images and recorded images simultaneously.
31. Angle of view
Internal or external
Static or PTZ
Colour or Monochrome
High or Low resolution
Available / Changing light levels
Site orientation
Power availability
Data Protection Act
32.
33. Alarm Inputs send telemetry signals via the DVR
to automatically control / preset camera position,
record rate, image resolution, etc…
Alarm Inputs triggered via:
• External detection devices
• Panic Button
• Access Control Equipment
34. Lamps are usually Tungsten
Heat generated by the bulb’s wasted energy
Aluminium-plated reflector
Short life
High power consumption / High cost of
ownership
Range = various angles – Wide / Medium /
Narrow
35. Use solid state technology
Long life
Better performance & efficiency
Gold-plated reflector
Low power consumption
Need IR sensitive cameras
Range = 10° ~ 60° / 20m ~ 175m >