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MANTECH SECURITY :
CCTV Surveillance Systems
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FAQ's for CCTV (Closed Circuit Television Cameras)
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Q : Can CCTV systems
be installed to deter & stop criminals ?
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| Cameras supported with DVR ( Digital Video Recorder ) have been proven to act as a
deterrent for criminals and a tool for collecting evidence for prosecution of
those who break the law.
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Q : Should I select
a CMOS or a CCD type Camera for my CCTV system ?
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| MANTECH-SECURITY camera ranges uses Sony & Sharp CCD
chipsets. There are two common types of CCTV cameras, CMOS and CCD. CMOS based
cameras are generally cheaper but do not produce as
clear and sharp images as CCD cameras. |
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Q : When ordering a
Camera, should I purchase the lens separately?
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At MANTECH-SECURITY, we supply a series of
quality lenses such as: Fixed Iris Lenses, Manual Iris Lenses, Vari-Focal Auto Iris lenses,
Motorized Zoom Lenses, Infrared Lenses, Pinhole Lenses and Board Camera Lenses
Series. A vast range to choose
from, to suit your specific need. Please refer to the chart below for lenses
sizes & optical / visual effect. |
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Q : Can I install a
camera to capture license number plates during day & night
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We have on offer the very latest techniques, including
optics and illumination to provide clear images of License Number Plates in both
day & night conditions.
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Q : What methods
are available to retrieve and Backup recorded Video/Audio MPEG data
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There are a number of options to Choose from, namely :
a) Removal of the hard disk and
send for investigation.
b) Copy from the DVR onto a conventional video tape.
c) Send video clip across the Ethernet.
d) Use a network or USB connection to a PC with a CD/DVD burner
e) Built-in DVD/CD Writer
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Q : What criteria
to consider when selecting a DVR recorder
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1 Number of Channels.
Most DVRs are classified by the
number of channels or cameras that can be connected. Typical configurations are
1, 4, 8, 9 or 16 channels. Consider carefully how many cameras are required,
both now and in the future.
2 Multiplexing of Channel Display.
The better DVRs have full
multiplexer functions built into them. This is the desired type of product. A 4
channel DVR will split the screen into 4 and display one camera in each window.
Similarly a 9 channel DVR will give a 3 by 3 matrix to display all channels.
All other functions of multiplexers like alarms, time and date stamping should
be available.
3 Frame Rate.
This is the maximum number of frames or images that can be
recorded in a second. Most common DVR specifications are 25 frames per second. DVRs with higher rates, 50 or 100 frames per second are
only specified for high end systems. Check that the quoted frame rate refers to
the British PAL system. Some products quote 25fps for NTSC and 18fps for PAL.
4 PIR Motion Detection.
Depending on the application, it is not necessary to set
the DVR to continually record. The better DVRs have a
built-in motion detection system such as Artnix DVR Series . This function is performed by electronically
monitoring when the composition of the image changes and consequently setting
the DVR to record mode. If this function is not included then it will be
necessary to use traditional PIR sensors.
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Q : Why and when should I consider selecting an
Imitation Camera
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Imitation or Dummy Cameras
are another cost-effective solution to deter intruders or criminals. Imitation surveillance
cameras look like the real thing but are a fraction of the cost and are easily
installed. Make your home or business look like it has a great security system. Imitation cameras and security
surveillance systems have proven to be an excellent crime prevention device.
Our Imitation cameras
have a real look including red flashing lights on the front of most cameras.
All cameras have mounting brackets for easy installation. They have the look of
an expensive video surveillance system, without the cost. We offer a complete line of excellent simulated imitation
cameras some with motion detector. One dome camera can be placed in the middle to give
the illusion that the entire area is under surveillance.
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Q : Is there a
formula to calculate the Angle of View for the Lens selection
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The focal length to
cover the object can be calculated from the next formula.
f : focal length of lens
V: Vertical size of object
H: Horizontal size of object
D: Distance from lens to object
v : vertical size of
image (see the following table)
h : horizontal size of image (See the following table)
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| Format
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1 inch
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2/3 inch
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1/2 inch
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1/3 inch
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9.6mm
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6.6mm
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4.8mm
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3.6mm
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12.8mm
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8.8mm
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6.4mm
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4.8mm
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Examples |
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