Need advice on system design

[TheCaretaker 0]

I work at a small school and recently we have had problems with intruders on site. I have been tasked with finding out more about CCTV systems suitable for use on the grounds. The trouble spots are likely to move during the school year, for example at the moment with the summer people are breaking in to use the school swimming pool. So the suggestion is to have a system with one camera which can be moved to cover the vulnerable areas.

 

My questions are, is this a good idea? Since the school is networks for computers is an IP system better that analogue? Would a DVR be a good idea or a more basic set up with a camera feeding back to video recorder.

 

Any suggestions, advice, etc would be very welcome.

 

Cheers

 

Ed

[TastyHuman 0]

I'm new to this myself but it seems if you want a mobile and expandable system then IP wireless would be the way to go. That way you don't have to mess with running wires to wherever the camera is needed on a given day. It would be easy to expand with additional wireless cameras as the system grows. If there is a large coverage area it would be easy to either put the recording system (pc, dvr, etc) and wireless access point on a mobile cart and wheel it around, or add additional wireless access points or repeaters to extend the system.

 

Plus you could use much higher resolution cameras than analog, which may well make the difference between identifying a face or not. Analog would not give you a choice of higher resolution.

[RickA 0]

I think you would need to look at what you are trying to cover, How many

buildings and distances. For us to provide any real answers we would need more info.

[TheCaretaker 0]

To start with my questions will be quite vague, as this is an area outside my field. However I have been tasked with finding out more information. The school I am at is a private school that covers several acres, the majority of the buildings are clustered together and networked.

 

The pupils are extremely well behaved so there is no need to monitor corridors, etc. Any trouble on site comes from outside.

 

There is a heated outdoor swimming pool with two changing rooms that is a target for local youths to try to use during long hot weekends. The problem being that while there they cause a mess and vandalise the facilities. The changing rooms face the pool and are close enough to the main building to run cabling across. Since the cameras are not needed during the week and for parental concerns wouldn't be used while the children are on site. The school Bursar would like a system that can be quickly and easily set up to monitor the pool compound certainly during the school holiday periods and over occasional weekends.

 

Equally there are school events which require equipment being hired and left onsite for a few days. Again this is going to be close to school buildings, 10 - 15 meters max. The idea is that if we have one camera this could be moved to cover the required area.

 

My concern is that once we have purchased a system if it proves useful then they may wish to expand it, so I don't want to end up with a system that is going to be useless in the future.

 

At my last school they had an analogue camera that fed directly to a video recorder. The images captured were rubbish, unless you knew who the culprits were it was impossible to identify them, unless you zoomed into an area, but then you missed huge areas of the school grounds and it was all pretty hit and miss.

 

Just before I left they purchased a couple of DVR's and ran a seperate network for cameras across the school. It then became possible to view the results on computers linked to the school network. But that system was far in excess of the requirements here.

 

The footage we capture would need to be of a quality that would assist the police to identify any intruders and be able to be used in prosecution.

 

Thanks for your replies so far, and please bear with me as I try to get up to speed. Are there any good websites where I can go to learn more.

 

Cheers.

[Squiffy 0]

A four channel DVR with networking and simple fixed cameras should be adequate for your existing requirements. If you have a large budget then obviously you can go more up-market.

 

Look for something that gives around 12.5FPS per channel for recording and ideally D1 resolution.

 

If these are just local youths 'messing around' then the mere appearance of a camera may be a sufficient deterrent but it should be vandal proof (or out of easy reach), as should the cabling. Put two cameras (or more) in the location of interest to ensure you cover blind spots and of course lighting is a factor. A photo of the location may enable others to make a better assessment of siting the cameras and other requirements.

[TheCaretaker 0]

Thanks for that reply, 4 channels should as you say be more than enough, I understand FPS, but what is D1 resolution?

[Squiffy 0]

D1 resolution is 720x576 pixels for PAL and 720x480 for NTSC. Think of it as normal TV resolution. Lower resolutions encountered tend to look more like the standard video you'll find on YouTube. Actual quality of the image is down to the encoded bit-rate, the more the better and compression is used to squeeze more of these bits in without too much degradation.

 

For good results with efficient use of memory (i.e. more storage possible on the hard drive) opt for for a DVR which uses H264 compression.

[TheCaretaker 0]

Thanks for the advice so far. I'm guessing storage will not be a major problem, if the system can be set to record only between certain hours, footage will not need to be stored for longer than a couple of days if there is no problems.

 

I will post some pctures of the site here tomorrow to give some idea of the areas we are trying to cover.

 

More questions:

 

Are wireless camera's worth going for, are they reliable? I use wireless network at home, but I often run into problems if the neighbours routers are picked up which interfers, we have a large residential estate surrounding the school and I wonder if wireless cameras suffer from the same problems.

 

If not what is the best connection between camera and DVR?

 

When a DVR is described as 4 channel at 25fps, are the fps divided per channel? I seem to remember at the last school if one camera was set to max frame rate the others suffered.

 

Are there any 4 channel systems that you have used that you would recommend?

[Squiffy 0]

I would avoid wireless cameras, unless they're working on frequencies other than the usual 2.4GHz region, as they're prone to interference from WLAN and microwave ovens.

 

As distance isn't a problem just normal cabling (coaxial cable and power) is fine with vandal-proof conduits in place where needed.

 

Usually when FPS is mentioned it's usually for all channels combined (to make it sound better...) so it's likely to be 6.25FPs per channel for PAL in the example you mention. While this may be adequate, the more the better, as it aids recognition of suspects. The lower the frame rate, the less likely it is that you'll have a suitable frame.

 

I can't really recommend any particular system but I'm sure many here will be glad to do so.

[TheCaretaker 0]

 

This is the front of the swimming pool changing rooms, the lightened area is where I would imagine mounting the cameras. The building behind is fully networked so extending power and cabling to here is not a problem.

 

 

 

This is the extent of the area that would need to be covered.

 

 

At the moment this is the other proposed area of coverage, it only needs coverage for the lightened areas.

 

p.s. sorry for the last picture, I thought I had resized them all

[Squiffy 0]

It looks like there are three possible entry points with the playing field area being very wide. Obviously wide angle lenses will cover the area you require but make recognition of suspects more difficult. So the use of four cameras would probably be for the best with perhaps two wide-angle lenses for a gerneal overview and two narrower angle lenses at strategic points to aid recognition. If that's a slight overkill for the area then you could always redeploy unnecessary cameras to somewhere else.