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The latest technology for CCTV Surveillance systems

Posted by in Security Articles on Oct 23, 2017 .0 Comments
The latest technology for CCTV Surveillance systems

The latest technology for CCTV Surveillance systems.

Most of you will be familiar with the surveillance camera footage which is aired from time to time on the TV when the police are looking for certain individuals.

Usually, the pictures are not very clear, details are difficult to make out, and facial recognition is almost impossible.

In the very early days of CCTV (Closed Circuit Television), cameras had to be monitored live, as there was no efficient way to record them.

Later, systems were developed which recorded on reel to reel tapes, and later still on VCR (Video Cassette Recorders).  The limitations on speed of capture and storage capacity, meant that the cameras were normally very low resolution, and the tapes needed replacing regularly, requiring a large number of tapes, making it quite expensive.

Since the turn of the millennium, CCTV technology has advanced in leaps and bounds.   The first development was Digital Video Recorders, (DVRs), in which the video is recorded onto a computer type Hard Disk.  Using these enabled the systems to record for longer, and made the technology easier to use, as the older recordings could be over-written whilst retaining the latest ones.

Early DVRs recorded at a resolution of CIF which was 352 x 288 pixels. Although this was an improvement on the older tape systems, the resolution still did not give very good detail. To compound this, the picture was compressed in order to provide a longer recording time, reducing the detail still more.

Improvements in Hard Disk technology, higher capacities at a lower cost have again been implemented into CCTV technology, and the standard not so long ago was called D1, which gave a resolution of 720 x 576, but again was compressed, using H.264 technology (which was an improvement on earlier compression algorithms), but still giving reduced detail.  This was the standard for DVR systems until fairly recently.

In the late 20th century, a new technology was introduced, IP or Internet Protocol cameras.  The advantage of these was that the signal was transmitted digitally over a network, with no compression, giving a much clearer picture, and Megapixel cameras could be used.  It took a long time for this technology to be accepted widely, as at first it was very expensive, and only a few manufacturers produced them.  Also, they tended to use proprietary systems, which were not compatible with other manufacturers. This meant that users were tied in to that manufacturer’s technology, therefore a captive market.

To overcome this problem, in 2008 the Open Network Video Interface Forum (ONVIF) was formed by a number of manufacturers, producing a standard for IP connectivity.  There was also a competing group which formed another alliance, Physical Security Interoperability Alliance (PSIA) with their own specifications.  ONVIF seems to be the overriding standard, and most IP cameras produced today specify that they comply with ONVIF 2. 

This sounds like the perfect solution, but in fact ONVIF only seems to ensure that cameras to this standard can work with other cameras and recording devices which comply with this standard.  The reality is that although using an ONVIF compatible system, individual manufacturers still produce their own proprietary software, so to ensure that you are able to use all the functionality of a particular camera (e.g. Motion Detection), you need to use the software or recording device manufactured by the same manufacturer.

There were other problems with IP camera systems – firstly, as the signal is transmitted over a network or the Internet, there was a greater risk that the signal could be accessed illegally, and access gained to the network used.  Also, with IP cameras there is always network delay, or ‘latency’.  IP cameras have continued to be reasonably expensive, and in general they are more difficult to set up, as each camera is like another ‘computer’ on the network, and must have its own IP address etc.

To counteract these weaknesses, the industry has been working on ways to improve the directly connected analogue type cameras, in order to reduce the compression, and increase the resolution.  There are three basic technologies which have been developed since 2012, by different manufacturers.

HD-TVI (High Definition Transport Video Interface), HD-CVI (High Definition Composite Video Interface) and AHD (Analogue High Definition).  All of these technologies are based on the older analogue system, and the video can be transmitted along existing coaxial cable as was used for analogue, but give the advantage of higher resolution and longer transmission distances.  In the early days, CVI and TVI were able to support a higher resolution than AHD, which was limited to 720p (1280 x 720), but in recent times, AHD has caught up, and can support 2MP sensors producing 1080p (1920 x 1080) and even sensors with 3MP and 4MP, giving resolutions up to 2560 x 1440. 

One of the advantages of AHD cameras is that transmission distances are greater (Can be up to 500 metres on coaxial cable), the resolution is good, and the prices are generally on a par with analogue, making them much more accessible for the average user.

As with all things, there is a trade off with these higher resolutions. Certainly you get much more detail, but the storage requirements increase in proportion.

Using D1 cameras, recording 7 days a week, 24 hours a day at approx. 15 frames per second, each camera would require about 55GB of storage.

720p Cameras for the same time and fps, would require approximately 150GB of storage, and 1080p cameras approximately 310 GB.

As you can see, a 1080p camera system with say 8 cameras, would use about 2.5 Terabytes of storage per week.  This could be improved by slowing the frame rate, or reducing the quality slightly, but illustrates the dilemma facing systems designers, particularly when designing a system for e.g. a club or pub, where the police requirement is usually for video to be stored for a minimum of one month.

One of the advantages of AHD cameras is that transmission distances are greater (Can be up to 500 metres on coaxial cable), the resolution is good, and the prices are generally on a par with analogue, making them much more accessible for the average user.

Manufacturers have tried to standardise on the new technologies, and most cameras produced today can be switched between analogue, AHD, TVI or CVI, making it easier for end users to update their systems.  To  match the multi-use cameras, the recording devices have also advanced, such that they are multi-use also, being able to record analogue, AHD, TVI, CVI and even IP cameras on the same device. These latest recorders are called XVRs.

Footprint Security sells a full range of IP camerasNVRs (Network Video Recorders) which record IP cameras over the network, 4-in-1 cameras, capable of recording Analogue, AHD, TVI and CVI, DVRs and XVRs

 

For further information, give Hugh a ring on 1300 852 400, or email to hugh@footprintsecurity.com.au for free, no obligation expert advice.

www.footprintsecurity.com.au