How Does CCTV work?

You ought to know this  before buying a CCTV security camera system.

If you do, you’ll know what types of CCTV to look out for.

You’ll also be ready with questions you should ask the seller to help you choose the best CCTV surveillance system for  your home or business.

A CCTV system involves a significant cash investment.

So, it’s wise to have a basic knowledge of the types CCTV surveillance systems before  you  splash your cash on a security camera system.

You must understand that CCTV comes in different shapes and sizes and functionality.

Choosing the right one for your needs could be a tricky affair

Of course a good professional would gladly assist you with advice, but it doesn’t harm to have a little background, layman’s knowledge on the types of CCTV so that you get your money’s worth and don’t end up shortchanged.

Here are some tips that will help you be better prepared to choose between the different types of CCTV and buy a system for your home or business premises.

Don’t worry if you don’t understand any of the technical jargon mentioned here.

It’s enough you get a broad idea of what is being discussed.

Meanwhile, let’s get down to a little basics on security cameras.

What is CCTV? and How Does it Work?

What CCTV means?

CCTV means (Close Circuit Television) .

They are security cameras that are connected to a central recording equipment.

The camera lens sends the focused image to a sensor from which the image is passed to the DSP (Digital Signal Processor).

Here’s an important point to remember. A quality lens would be more helpful than fussing over video resolution.

Clarity of images will be determined by lens quality. Based on your needs, don’t compromise on lens quality.  Ask the seller what kind of lens will you be getting and will it meet the quality you expect.

The type of lens you choose will determine whether distant objects are visible. Do you want car number plates to be visible or faces to be clearly seen? Then you should pay attention to the type of lens you choose.

As far as possible, opt for a zoom lens. Here you should understand the difference between digital zoom and optical zoom. You’re advised to choose optical zoom. Why is it better than digital zoom?

A digital zoom just enlarges the picture at the centre of the frame and cuts off the edges. The lens doesn’t do any work here, only some in-camera processing is done.

An optical zoom on the other hand is just like a zoom that a  film camera gives. You get sharper and fuller details of a distant object or view.

Digital Signal Processor (DSP)

The Digital Signal Processor converts the image into a TV signal which is then sent to the central location where it could be viewed on a television monitor or computer screen and recorded to a storage medium.

The transmission of the video signal can be done by a wired connection or a wireless one.

Two things must be taken into account when choosing the right sensor for the CCTV system.

The first is sensor type and the second is sensor size.

Generally CCTV sensors fall into two categories.

 CMOS is cheaper and has a lower power consumption but it doesn’t perform well when it comes to sensitivity to light. Thus the image recorded will lack clarity,

If you need clear identification of images, then a CMOS sensor may not be the best bet for you.

CCD consumes power as much as 100 times more than CMOS but it produces clearer images with minimum noise.

If clearer images are what you’re after, then you could do well to go for the CCD option, despite its ‘drawbacks.

Read more about the difference between CCD and CMOS.

Sensor Size
Sensor size is also important if image quality is your concern.

Most sensor sizes are either ¼ inch or 1/3 inch. The latter produces double the image clarity of the former. It also inputs more light which when passed to the DSP will result in clearer images.

A larger sensor gives the DSP more data to process and will be useful in producing clearer images in the event  a low-end DSP is used.

Types of CCTV Surveillance Security Cameras

Here are the types of CCTV that are commonly available in the market.

CCTV formats are important because they determine what video resolution you’ll get..

In the early days of the CCTV, this used to the standard format.

Resolution: 320×240

Quality : VHS

With the advancement of CCTV video technology this format has fallen out of favour.

If you’re looking for video quality in CCTV recordings, then you could do well to stay away from this format.

Resolution: 720×480
Quality: DVDThis promises good quality video recording.It’s the most popular format over the past decade. The video quality matches that of a DVD.It promises a resolution of about 400% higher than that of CIF.

Resolution :  (960×480).

Also known as WD1 or Wide D1.

This format gives you the ultimate in analog resolution – 34% higher than D1 and 500% higher than CIF.

Advantage : Wider letterboxed video.

WD1 is also  compatible with the RG-59 cable used in a previous system.

To get the optimum results, you could do well to get a 960H DVR and a 700 TVL Effio DSP to benefit from its higher resolution.

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As the name suggests an IP  (Internet Protocol) CCTV system merges video and audio into a single data stream.

This is then transmitted over a network or via the Internet through a Network Video Recorder (NVR).

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Video resolution is great -720P (1280 x 720) and 1080P(1920 x 1080) – both in progressive high definition video.

Here’s the resolution quality difference you’ll enjoy with an IP CCTV .

For 720p you get a 200 % better resolution than what’s offered by the 960H format.

You get  300% more than the D1 format.

As compared to CIF, it’s a  whooping 1000% increment.

The 1080p on the other hand offers 200% better quality than 720p

There’s 400% improvement on the quality offered by 960H and 600% compared to D1.

And compared to CIF, the quality improvement is a staggering 2000%.

It comes with a video resolution of (1920×1080).

If you’re looking for the best high-definition surveillance camera system, this is the format to go for.

What then is the difference between an IP close circuit TV system and the HD-SDI?

The advantage of the HD-SDI format is that it functions like a normal analogy surveillance camera system.

In most instances you save on installation cost as you could use the RG-59 cable from a previous system.

But then you would still have to spend on a DVR. if you’re going for a high-end one and the cameras come with steep pricing as well.

But then you would be rewarded with Blu-ray video quality if that’s the kind of video recording you wish..

It comes with 720p and 1080p  (1280×720/1920×1080).

This format is set to revolutionise the CCTV field.

It offers the best of both worlds- it’s a format which comes with the functionality of HD IP and HD SDI for an attractive price.

One advantage of this format is that long cables, up to 1500 ft long could be used to  send and receive video, audio and data.

It’s good to know the variety of CCTV formats available before you go out and buy a system.

If you don’t have the budget or if you just require a basic CCTV setup, opt for a D1  system .

• Do you  need just a basic setup to monitor comings and goings?
• Do you need clear  images of faces and objects ?
• Would you prefer a wired or wireless system?
• Would you need an indoor CCTV system or an outdoor System?
• At what time of the day do you expect the CCTV system to serve you best? If it’s to monitor happenings at night, then you would need a camera with night vision capability.
• Would an IP Network Camera (see below) be a better option?
• Would you need a single, double, 8 or 16 camera setup?
• How much is your budget?