Before starting to compare surveillance systems or evaluating potential vendors, sit down and consider your closed circuit television (CCTV) needs. First, consider what you want to monitor with your surveillance system. General comings and goings? Vehicles? Do you want to see faces, merchandise, crowds? Once you decide what you want to see, choosing components will become easier.
Next, decide what picture quality you need in your surveillance systems. Quality can refer to both how detailed the image is and how fast the frame rate is. Frame rate is simply a measure of how many individual pictures make up the video. "Real-Time", what you see on television, is 30 frames per second. Most often, lower end surveillance systems record at slower rates, which result in more jerky-looking images but saves on recording space, choose a system which allows you to adjust the record / playback and streaming video rates.
Think about how your surveillance system will be monitored. Will you simply
record at all times, and only review the video when a problem occurs? Or
will you have a dedicated employee watching for trouble? Also, with multiple
surveillance system cameras, you have the option of connecting each to its
own monitor, or combining multiple images onto one monitor.
You also should decide whether your priority with your surveillance system
is to deter potential crimes or to catch perpetrators. If you are more
interested in deterring certain activities, large, visible cameras are your
best bet. Trying to catch criminals without them being aware of it requires
hidden surveillance system cameras, which cost more for hardware and for
installation.
With these questions answered, you will be able to speak with more knowledge
as you explore the range of surveillance system options.
One of the newest trends in the surveillance system industry concerns
digital recording. Only a few years ago, most closed-circuit TV systems were
paired with the familiar VCR to record images. However, digital video
recorders (DVRs),
which record onto hard drives instead of tape, offering you complete control
on how video is recorded, played back, and remotely viewed.
For businesses that do not want to change tapes constantly, DVRs definitely
are the way to go. While security VCRs usually offer a time-lapse mode that
lets them record for long periods of time, the resulting images are not a
good record of events - they record only one snapshot every eight seconds,
and require very high maintenance and LOW ROI
To get higher quality, you need to change tapes every day or more often. DVRs,
on the other hand, can record for months.
Rough costs for a complete, installed surveillance system is $500 to $1,000
per camera, plus the cost of your recording device. Good DVRs generally
start at $1800 to $2,500 and get more expensive with the more HDDs you add.
With even a modest upfront investment, surveillance systems will shrink the
long-term problem of theft.
Security Cameras are one of the best ways to monitor your home or office.
First you must decide whether you need an indoor or an outdoor system and
whether or not to use closed-circuit (CCTV) or wireless cameras, Please
note: Most wireless cameras require a (CLOS) Clear Line Of Sight for proper
transmission of video signals. Day or night use will also affect the type of
camera you by, some have built in infra-red that allow them to 'see' in the
dark, others are infrared sensitive.
Consider the following when choosing a
CCTV camera
- Sketch out a Floor Plan: Put in all camera locations. Consider the distance to your surveillance zone: Are you 5 feet or 15 feet away from your surveillance target area? It is best to locate your camera as close to the surveillance area first, and then choose how much zoom you need. Do you need 4mm, 8mm or 12mm lens, or a PTZ camera?
- Field of view or area of surveillance: Take photos of areas you want to cover from the proposed camera locations. What lens you need depends what you want to see and how far away and how wide a viewing area. Wide angle and fisheye lenses are available.
- Resolution: Do you want to capture a person’s face or a car license plate? Each camera location will determine which lenses would maximize your surveillance potential. Do you need 50mm lens or standard 8mm?, Varifocal lens are also available and are mostly used when distances the camera is to view are unknown or "not sure" what the distance will be. This will allow you to adjust the (FOV) Filed of view as you see fit, and give you a wide veriety of shots that may work out better then you thought in the first place!
- Vandalism potential: Will your camera be subject to damage? Vandal proof cameras are available, and mainly come in a Dome.
- Lighting: Is the space well lit or dimly lit. Are the lights turned off at night? Do you want to monitor the area with the lights turned off? Do you need infrared CCTV cameras or low light cameras?
- Budget: Just like any technology, the more you spend, the better the system you get. Keep in mind a low cost, low quality camera will provide you with unusable pictures, you can turn on the nightly news and see a perfect example of what we are talking about. A news brief will talk about a robery and when they show you a picture of the theives you will find the neighborhood kids probably do much better sidewalk chalk drawings than what the video of the low quality system produced!
Surveillance cameras are becoming more popular and, most importantly, more accessible to the average person. Huge store chains or gated communities aren’t the only places than can afford the benefits of surveillance cameras anymore. They are available for your home and office needs, no matter how simple or how elaborate a setup you require.
Your home, your office, your store, your family -- these are just four reasons why you would want to purchase a surveillance camera. If you put your time, energy, and resources into these, why not take the extra step and insure what matters most to you? Video cameras designed specifically for surveillance give an extra measure of safety and security.
You have a broad range of video surveillance cameras available to you. Understanding the different kinds will make it easier to determine which one suits you best.
- Outdoor Cameras - Outdoor cameras need to be able to withstand extreme temperatures and humidities and usually come in a weatherproof casing that also helps protect against vandalism.
- Infra-Red Cameras - These cameras have infrared LEDs installed around the lens of the camera. This provides light the camera can use to 'see in the dark' even when no outside light is available. In some low light installations, a day/night camera will work as well.
- Day / Night Security Cameras - Day / Night cameras have a super sensitive imaging chip in them. This allows these cameras to work great in low light with no infrared lighting needed. Low light means that there is some light available but not a lot, for example from street lights or even moon light. If your application has absolutely no light then you'll need to use infrared instead.
- Mini Security Cameras - Mini cameras are some of the smallest available, but still offer extremely good resolution and are ideal for unobtrusive surveillance. The compact design of these coin cameras make them very easy to hide and difficult to see.
- Bullet / Finger Cameras - Bullet / Finger cameras are small, compact and can be placed almost anywhere. These cameras are great for covert surveillance. The lens is built into the camera and cannot be switched. The main advantages to the bullet camera are their low cost and their small size.
- Dome Cameras - Dome cameras are
a popular style. Dome cameras present a streamline and professional
look to any company, organization or building. They are available in
both black & white and color formats. Some dome cameras come in an
armor dome to protect against vandalism. Typically, they're only used
indoors.
Fortify your home or office today
Surveillance cameras are extremely helpful in protecting your home or office environment. You can check up on your nanny or employers, make sure nothing suspect happens at your home while you’re away, monitor the children from another part of the house, and make sure nothing strange is going on in the office parking lot when you leave after dark.
Don’t wait to protect your home or office -- act now. Browse through your surveillance camera options today.
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Security monitors come in a variety
of resolutions in both black & white and color. The quality of
security cameras you are using will usually determine the type of
monitor you need
- A color monitor used with black & white cameras is pointless
- Some feature remote viewing and control from a PC
- Typically they come with auxiliary inputs for analog video and a secondary monitor output connection
- Standard monitors are usually more powerful, but flat screen versions take up less space and can be mounted to the wall
If you get stuck on some CCTV terminology check our Glossary
- Always use more cable than you need. Leave plenty of slack
- Test every part of a network as you install it. Even if it is brand new, it may have problems that will be difficult to isolate later
- Stay at least 3 feet away from fluorescent light boxes and other sources of electrical interference
- If it is necessary to run cable across the floor, cover the cable with cable protectors
- Label both ends of each cable
- Use cable ties (not tape) to keep cables in the same location together
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The most common type of connector used with coaxial cables is the
Bayone-Neill-Concelman (BNC) connector (see diagram below). Different
types of adapters are available for BNC connectors, including a
T-connector, barrel connector, and terminator. Connectors on the cable
are the weakest points in any network. To help avoid problems with your
network, always use the BNC connectors that crimp, rather than screw,
onto the cable.
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When deciding on what power sources to use, always use "REGULATED"
power supplies.
These power supplies will send the correct amount of power to your camera, if you use too high a power source it will burn out your camera and void your warranty. We also have a few power Boxes to choose from, you can choose the right one by how many cameras you are wanting in your system, but don't forget room for upgrades.
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Most CCTV cameras are now almost exclusively 'CCD' sensor type. CCD
stands for Charge-Coupled Devices. These are light-sensitive chips, the
sensitive area being split into a large number of individual pixels
(Small dots on the chip). An image from a scene is focused through a
lens onto the chip surface and charge is built up in each pixel
proportional to the intensity of the light falling on it. Hence an
electrical representation of the optical image is formed. Typical active
pixel counts for CCD sensors are between 250,000 and 500,000 pixels.
Cameras are available in both monochrome and color types.
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Note that WECU Surveillance Security Cameras, supply cameras without
lenses filled. This is because there are many different types of cameras
and even more types of lenses and so it would be impractical, and very
expensive, to stock all possible permutations and combinations to meet
each application.
Hence - REMEMBER to include the LENS!
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The field of view (FOV) is based on the camera & lens. WECU
Surveillance.com has many different types of Lenses to suite any and all
of your CCTV security camera needs. 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. See the FOV diagram below for approximate views with different focal length lenses.
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The main criteria of a camera's performance are its sensitivity and
resolution. Sensitivity is a measure of the minimum amount of light
required by the camera to give a 'useable' Image. Resolution defines the
amount of picture detail in the image produced by the camera.
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The CCTV industry has many ways of stating an individual camera’s
sensitivity performance. Most common is minimum scene illumination
required to give useable picture at a particular lens aperture.
- Camera 1 requires a minimum scene illumination of 0.1 lux at a lens aperture of f 1.4 to give a useable image.
- Camera 2 requires a minimum scene illumination of 0.05 lux at f 1.0
to give a useable image.
This appears to say that camera 2 is twice as sensitive as camera 1 because it needs half the light to give a useable picture. In fact the cameras have equal sensitivities because the aperture through which light is allowed to fall on the sensor of camera 2 is twice the area of that for camera 1.
Typical sensitivities (defined as minimum scene illumination required for useable picture with lens aperture at f 1.4) for current CCD cameras are as follows:
- Medium Performance (General purpose) Monochrome 0.5 - 0.25 lux
- High Performance (Low-Light/Outdoor) Monochrome <0.20 lux
- Medium Performance (General purpose) Color 3.0 lux
- High Performance (Low-Light) Color < 2.5 lux
This is inherently subjective.
Another, more objective definition is the minimum scene illumination required by the camera to give full video output
I.e. 1v peak to peak. Few manufacturers use this definition! Most manufactures provide a figure in LUX which is actually a light level the figures quoted are often like this 0.1 LUX. The problem with this is that to get a true representation of the actual sensitivity of the camera the lens apertures must also be compared. Lens apertures, i.e. the size of hole that light can pass through in the lens, must be compared in order to get a true comparison of performance.
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Choosing the correct camera to operate in the ambient light conditions
is possibly the most important although most tricky specification to
understand.
- Full Summer Sunlight: 50,000 Lux
- Dull Daylight: 10,000 Lux
- Shop/Office environment: 500 Lux
- Dawn/Dusk: 1 - 10 Lux
- Main Street Lighting: 30 Lux
- Side Street Lighting: 0.5 - 3 Lux
Light levels are usually measured in Lux. This is a measure of the light energy arriving on an area 1m2 of surface per second.
Typical light levels are:
The golden rule when deciding which camera to use for a given lighting condition is not to choose one that will only just give a picture. Try to give the camera approximately 10 times its quoted minimum scene illumination. Most cameras will be able to cope with excess light. The major problem is when they do not have enough light to produce a picture.
The sensitivity of covert cameras with pin-hole lenses are often quoted as 0.1Lux @f1.4. This seems to indicate that the camera will work in ¼ moonlight. Actually the pin-hole lens will have an aperture ratio of something like f4 and so the camera will need approximately 1 Lux to produce a picture.
Unless your house is directly under main-street lighting the light level is probably less than 1 Lux at the front and even lower at the back. Bright security flood lights in theory help but often produce dark shadows a short distance from the house.
A monochrome camera rated at 0.05 Lux will produce reasonable results. Color needs a little more. However, color cameras achieve good night-time vision by switching to a monochrome mode. You will never get good night-time color pictures without huge amounts of additional lighting. So think carefully about the added cost of color over monochrome cameras. As most people are used to color television it sets a standard so it is very common to still select a color camera knowing it will switch to monochrome mode at night.
Monochrome cameras respond well to additional IR (infra red) lighting. With this in mind true night-vision cameras include a ring of IR LEDs. Color cameras also offer IR illumination but as stated previously will switch to monochrome at night even with the IR LEDs turned on. These are true night-vision cameras and are rate at 0 Lux.
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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.
IR Cameras are cameras that 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.
- Resolution is measured in lines and normally only horizontal resolution is quoted.
- Vertical resolution of a camera is of little interest because
pictures are generally speaking limited by the scanning system used to
produce the image.
In the UK and Europe this is the CCIR system, which defines that a picture is built-up from 625 lines across the screen. Of more interest in measuring camera performance is horizontal resolution. This is the maximum number of black or white areas that can be identified across the picture. This is always specified per monitor height.
A typical general purpose monochrome camera has a horizontal resolution of 380 lines. This means that it should be possible to resolve 380 x 1.33 i.e. 505 individual actual lines of black, white or grey along any one line of a CCTV picture image. (The factor of 1.33 comes from the fact that a TV picture has an aspect ratio of 4 : 3)
- Medium Performance (General purpose) Monochrome 380 lines
- Medium Performance (General purpose) Color 420 lines
- High Resolution Monochrome 600 lines
- High Resolution Color 540+ lines.
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Cameras will be quoted as 1/2", 1/3" or occasionally as
2/3". Newer cameras will be referred to as 1/4". This refers
to the format of the camera and defines the size light-sensitive area of
the imaging device used in the camera. In itself it gives no measure of
a camera’s performance although generally the smaller the format size,
the smaller the light gathering area of the sensor. It is provided for
information to enable the installer to match the camera to the correct
lens. Camera formats are getting smaller in order to reduce the costs of
the imaging devices and hence the cameras themselves as well as the
lenses put onto them.
