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IP CCTV – The real difference

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Posted by admin | Posted in Zenien Content | Posted on 05-11-2011

There is a lot of hype at the moment in the security market about IP CCTV. Some people see it as the future, some that have been in the industry a long time see it as a fad. Really what is the difference and what does going IP for your CCTV system mean to you?

IP CCTV has been around for around 15 years, when Axis Communications released the first IP camera. Back then the camera struggled to impress due to most of its specifications being worse than analogue, but it was a start and it lay the benchmark for some impressive developments. An IP camera is basically a camera that rather than delivering footage over analogue video streams (using coax cable) it delivers the footage and other data using the Internet Protocols (TCP/IP Packets). In short, the camera is a little computer system and it processes the footage into packets of binary information and sends it across a standard computer network to a Server computer that then stores the footage and allows access to it.

Whilst IP CCTV has been developing for 15 years, Analogue CCTV systems have been around for over 50 years in one form or another and at the moment they are still very widely used. They are generally cheaper than IP CCTV due to their simplicity and existing mass produced components. If you after a cheap and simple CCTV system and you are not entirely worried about fantastic image quality, expandability or flexibility, really you cannot go past an analogue CCTV system… That however is slowly changing.

Limititations
An analogue camera unfortunately, is limited by how the data must be transferred over coaxial cable. Many years ago, computer networks also ran over coax cables and we can tell you from experience that they were a nightmare to support and very slow. The IT world moved on to ethernet cables over 15 years ago yet the analogue CCTV world kept running with coax. It is the limitations in the amount of data and restrictions on how the can be transferred over this cable that is the primary limiting factor of analogue CCTV. You can buy an analogue camera and an analogue video recording solution from two different manufacturers and be pretty sure that they are going to work together. This standardisation and the limiting bandwidth on the cable, plus the way the information is transmitted is what is holding analogue cameras back. IP CCTV cameras on the other hand kept with the significantly more advanced computer networking standards and as such face very few limitations on bandwidth, the type of data that can be transmitted and the different transmission mechanisms (eg: fibre optic, wireless, across the internet etc).

So what does IP CCTV give me that Analogue does not?
Because IP CCTV has far fewer limitations and because they have significantly more processing power inside each camera, they have many advantages over analogue. Below is a list with an explanation of each feature.

Resolution – IP CCTV cameras can scale up to amazingly high resolutions (number of pixels/coloured dots per image area). Analogue cameras are typically limited to around 720 x 575 pixels whilst the average 3 megapixel IP camera provides 2048×1536 pixels. If you look at the number of pixels in total of each image, analogue gives you approximately 414,000 pixels whilst a 3 megapixel IP camera delivers 3,145,778 pixels in each full image. Thats 7.5 times the number of pixels, which directly relates to (but is not the only factor) image quality. IP cameras now can go right up to 16 Megapixel and whilst we see this is as mostly unnecessary, it still makes for amazingly detailed images should the particular circumstances require it.

Remote functions – Having more of a bi-directional communication channel such as IP networking provides us the ability to do much more with a camera from afar. Often we install cameras, align them and test that they can been seen on the network, then complete most other functions of the camera’s setup remotely either elsewhere on-site or across the Internet. This includes features such as remote zoom, remote focus and allowing us to tell the camera which part of the image is more important and as such adjust its shutter speed, aperture etc to focus on providing the best quality image in that area as its priority. We can also apply privacy masks or block out an annoying spotlight that would ruin an analogue camera’s ability to provide good images. If something changes on the image (eg: a tree is cut down, some shelves are moved, a light is installed) we can easily login remotely from our office and alter the camera, as such providing significant savings in travel time and staff costs.

Remote Input/Output – Most modern day IP cameras have a significant amount of logic ability built into them. For instance most IP cameras have input/output ports on the camera which can be used for the camera to either receive an input (eg: someone walks through a door out of the viewing area, the camera receives an input then instantly pan-tilt-zooms over to the door to see who cam through for 5 seconds, then goes back to what it was covering before) or to create an output (eg: camera senses that a car drives the wrong way up a one-way street, send an SMS to security and automatically shut the security gate to prevent the vehicle leaving). In short the cameras can act as little Programmable logic controllers (PLC’s) and can be integrated with alarm systems, plant shutdown sequences, lighting controls, access control systems or building management systems. We are also seeing these cameras used for much more than security purposes as unlike physical sensors that wear out or get dirty and do not work as well, the cameras “see” and react which is significantly more reliable.

Edge Recording – Apart from the fact that TCP/IP (Internet Protocol) was designed with resilience and the ability to automatically route traffic via alternative routes in the event of a network link failure, TCP/IP and in turn IP cameras can go one step further to weather the storm of a network link outage. Now with many camera manufactures and Video Management Software (VMS) systems, you can place localised storage (eg: SDHC card) and providing the camera still has power (via PoE cable or other power supply) the camera will continue to record, but to the SD card in the event of a network failure. When the network issue is repaired or restored, the VMS software will fetch the CCTV footage from the cameras and slowly ‘stitch’ it back into the main CCTV archive as if no network outage occurred.

Power over Ethernet – Nearly all modern IP cameras are now utilising Power over Ethernet systems of some sort. Power over Ethernet (PoE) is a standard that allows for both computer data and for power to run over the same physical wire bundle (single cable with 8 cores). This is done by using either Cat5e, Cat6 or some of the newer Ethernet standards and utilising spare wires to inject power for the camera down. The result of this is that the camera gets a high speed dedicated networking link (generally 100mbit or Gigabit) as well as a 48v (depending on camera and PoE class) to power the camera itself. The advantage of this in terms of ease of installation, reliability and installation costs are fantastic. Analogue cameras require two cables (in most cases), one 2 core cable for a 24VAC (typically) power feed and another thick and annoying to work with coaxial cable to send its limited amount of analogue data down. I will not dwell on the other benefits of having ethernet cable everywhere and being able to leverage existing ethernet cabling for CCTV as that is out of the scope of this article.

Viewing Angles – Put simply, higher resolutions and computer controlled cameras allow IP cameras to support significantly greater angles of coverage whilst still providing very useful images. The processors in the cameras can do more and the advanced software can almost completely remove effects such as fish-eye stretching issues.

Having rambled on sufficiently, if you have read this far, yet only really touched the surface of the technical differences between IP and analogue, hopefully you will sense our enthusiasm, passion an excitement by the migration of the CCTV and other security systems into the IT/IP world. Yes, perhaps I am somewhat biased towards the IP systems with a career background in computer systems and IT, but once you’ve seen the technology, the differences are astounding.

For more information on IP CCTV, Integrated Security Systems, Corporate IT support or any other technology related query, please to not hesitate to contact Zenien using the details on our contact us page. Thank you for reading this post and I hope the article was useful.

– Cameron Watts

 

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