Home

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C.C.T.V. - Continued - 2

Enhanced Systems with Detection

There is no doubt that Closed Circuit Television considerably enhances the level of security provided by a static Security Guard. To further enhance security, detection devices or video motion detection can be incorporated to provide a warning of an intrusion into the protected area such as over a fence line. This provides part of the solution but the problem is however, that even if a monitor automatically displays the image from the camera surveying the area, by the time the guard can react the intruder might well be off camera. Was it an intruder or a false alarm? The most effective solution is the inclusion of a Frame Store which will allow Security Personnel to verify an 'Alarm' call (on a before and after basis) from a detection device such as a Passive Infrared Sensor in order to filter out false alerts and act quickly and positively in the event of a genuine alarm. Each camera on the system is continuously looping a pre-set frames within the frame store unit. Following an 'alarm' the operator can then view these frames so activity can be checked before and after the point of alarm.

Video Motion Detection can be used to provide warnings and show traces of the path of the alarm etc. The principal of Video Motion Detection is that changes in the make up of the image from the camera are detected. However, when specified for outdoors great care must be taken to ensure that 'false alarms' will not be unacceptably high which can lead to complacency and therefore genuine alarms can be missed. Even changes in light, cloud movement etc. can create problems. The capabilities of such equipment varies dramatically and for the best results, set-up can be critical and time consuming as movement outside the protected area must be programmed out.

Signal Transmission & Remote Monitoring

Traditionally, video signals for C.C.T.V. are transmitted along coaxial or balanced twisted pair cables. For longer cable runs, the introduction of fibre optic cable runs means high quality pictures over a great distance. However, it is not always practical to run cables between cameras and the monitoring equipment. Wire-free links can be used but it must be remembered that where control of a camera (PTZ etc.) is required, transmission will need to be in both directions, all of which adds to costs. For relatively short distances, Infrared Transmitters and Receivers can be used. They can only be used 'line of site' and set-up and alignment is very critical. For longer distances, Microwave equipment can also be utilised for greater distances and Radio Frequency equipment is available that does not have to be 'line of site' but also has a limited range depending on the terrain.

Systems can be monitored remotely, any distance away from the camera equipment using the telephone network. Central Station Monitoring companies can monitor systems and even control gates etc. Alarm calls can be received with automatic display of the area of origination. Patrols can be made at any time which can include control of Pan/Tilt/Zoom cameras. However, the limitations of the telephone lines mean that viewing is not 'real time' in that there are delays (in seconds) and you can see the picture up-dating. The results are perfectly satisfactory as long as these limitations are accepted. Some systems will only operate with ISDN lines which provide a much faster rate of data transfer but are also more costly. Private lines can be rented from B.T. and where fibre optics are available, real time multi transmissions provide results comparable to 'on site'. However, the cost of rental of such lines is prohibitive for them to be used over great distances.

Remote Monitoring can be an attractive solution to secutity problems. However, the reliable detection of intruders in compounds and yards etc. within an acceptable level of false alarms poses a significant problem. Most monitoring centres have a ceiling on the number of alarm signals they receive within their standard charge so excessive false alarms can prove costly and introduce complacency. Basically, the method of detection deployed can be divided into two broad categories, ‘Perimeter Protection’ and ‘Internal Traps’. For perimeter protection to be effective, it must cover the entire perimeter. Any area of the perimeter not covered, provides a means of access. Without the addition of internal ‘Traps’ (which generally are not suitable when the site is operational), the incursion will go undetected. Transport and Logistics yards provide their own particular problems with parked vehicles blocking paths for detection methods that rely on line of site which makes the inclusion of effective internal ‘traps’ even more difficult to achieve. In many cases, the monitoring is required when the site is operational which rules out the inclusion of such traps.

The PulseSecureTM fence system is the perfect partner for the remote monitoring of CCTV because it provides reliable ‘alarming’ of any attempt to breach the perimeter. PulseSecureTM also deters and provides a physical and psychological barrier. Together, remote monitoring and PulseSecureTM provide a formidable defence and an extremely high level of security with the ability to differentiate between legitimate and unauthorised access even when the site is operational.

LENS ANGLES - HORIZONTAL

The size of the image as a proportion of the overall picture is illustrated here. You can see quite clearly that the wider the lens angle, the smaller the image is on the screen. If the circle were a persons head the chance of identification reduce with distance and a wider angle.

QUAD AND MULTIPLEXED RECORDING

The use of a Quad Unit allows the images from four cameras to be displayed on one monitor. However,there is usually a degradation of picture quality and as the recording is also in quad form the results can be unsatisfactory when identification is required. Multiplexed recordings allow the simultaneous recording of all camera images with the most basic types of 'Simplex' Multiplexer displaying full screen only both live and playback although there are variations between different manufacturers and models. 'Duplex' Multiplexers can display live pictures in full or multi-screen format and also display recorded images in full or multi-screen format irrespective of the live status when the recording was made. Multiplexers are available for use with up to thirtytwo cameras and multiscreen displays can be in various combinations, again depending on the model. Both Quad Units and Multiplexers work in conjunction with a VCR or Digital Recorder. However, the introduction of low cost multi camera Digital Recorders has rendered such systems virtually obselete.

INFRARED LIGHTING

Infrared Lighting is used to provide light which bareley visible to the naked eye for monochrome C.C.T.V. cameras. They can provide an effective solution but they can also be costly to run with many consuming 300 or 500 watts and to maintain with a short lamp life. The ominous red glow from an infrared light does provide a formidable deterrent to even professional criminals.

Infrared LED Illuminators have been developed that are now very effective and wheras the initial outlay is generally higher, running costs are substantialy lower and without the cost of regularly replacing lamps the overall savings can be quite high.

With the development of cameras which will operate at extremely low light levels there is often no need for additional lighting and I R lamps are being fitted and used pureley for the deterrent they provide. With this in mind the Owl 'Infraclone' has been developed which looks just like an I R lamp and lights up like an I R lamp from dusk to dawn but uses LED technology for a miniscule power consumption and a long life.

Glossary of C.C.T.V. Terms

Alarming: The ability of C.C.T.V. equipment to respond from a detection or switching device.
Ambient Light Level: Background or general lighting level.
Angle of View: The angle of coverage that a given lens will provide.
A.I. (Auto Iris): An electronically operated lens that automatically compensates for changes in light level.
Back Light Compensation: A feature which electronically compensates for high background lighting to reduce the silhouette effect.
C.C.D. (Charge Coupled Device): A 'chip' that has largely replaced tubes in cameras.
Depth of Field: The area of acceptable focus of an image. The wider the lens angle, the lower the depth of field.
Digital Signal: A signal thats level is represented by binary numbers.
D.V.S.T. (Digital Video Storage and Transmission): Digital technology that allows electronically compressed video pictures to be transmitted and stored.
Dwell Time: The time a sequential switcher will display the image from one camera before moving to the next.
E.I. (Electronic Iris): Automatically varies a CCD Camera shutter as a substitute for an auto iris controlled lens.
Field of View: The view achieved with a particular lens.
Frame: One complete 'still' T.V. picture.
Hardwired: Cable Link between two devices (e.g. Pan & Tilt Control)
Ident: Number or title superimposed on a video signal.
I.R. (Infrared): Illuminators - provide infrared light for night time surveillance. I.R.Link - a method of line of site wire free video transmission.
Iris: The part of a lens that regulates the light passing through.
Lux: Measurement of light striking a surface.
Microwave Link: Wire free video transmission.
Monochrome: Black and white.
Multiplexer: Allows simultaneous recording with individual playback of each camera by stacking a frame from each in sequence.
Real Time: Where the picture displayed is similar to a live picture.
Quad Splitter: Allows the viewing of four cameras on one monitor screen.
Telemetry: Facilitates multifunction applications with a single cable.
Time & Date Generator: Allows the current time and date to be displayed and recorder on a video picture.
Time Lapse V.C.R.: A video recorder that records frames with a pause between them to extend recording time.
Varifocal Lens: A type of lens which allows for manual selection of the desired picture view between two focal lengths.
Zoom Lens: Motorised lens which allows the operator to remotely zoom in on the subject.

Why Choose Owl?

Our Systems Advisory Service offers advice, a survey and quotation free of charge and entirely without obligation.

  • We offer keenly competitive prices.

  • We choose reliable equipment that performs well for a specific application.
  • We carry out installations efficiently and with a minimum of disruption.
  • We offer fully comprehensive maintenance which underwrites our confidence in the reliability of our systems.
  • We Supply Prominent Warning Signs (Sample) Most repairs are carried out in-house.

 

Our vast experience in the field and our frustration with the attitudes of many manufactures and suppliers regarding the glaring gaps and lack of availability of ancillary devices has led us to design and produce many of our own in-house solutions. This approach has allowed us to provide better solutions at much lower costs to our customers. For example, problems can often occur with video signal transmission due to peculiarities at specific sites, problems which are only discovered when the system is commissioned. The cost of a cure could be hundreds of pounds per camera so we manufacture our own equipment to overcome these problems which allows us to provide solutions quickly and stick to our quoted price.

Equipment designed and produced in-house includes:

  • Camera Housings

  • Specialised Camera Brackets
  • Video Distribution Amplifiers
  • Video Opto Isolation Amplifiers
  • Video Launch Amplifiers
  • Camera Power Supply Units
  • ‘Infraclone’ I.R. Lamp Substitute (Infraclone)

 

Local Authorities

We were formally approved by our own local authority (R.C.T.) for the installation of C.C.T.V. and Security Systems and have carried out work and have maintenance contracts with several other authorities.

We have installed a number of systems in schools (Security in Schools) and our system design using low voltage cameras and heaters with centralised power supplies obviates the need for the installation of mains power outlet at each camera location which represents a very significant cost saving. This method also addresses important safety issues as it eliminates the possibility of electric shock from the cameras and housings. For internal use, we have developed our own low cost vandal resistant wedge shape ceiling mount housing which has a stainless steel cover.

Warning Signs

Warning signs provide draw attention to a system and provide a substantial detterrent. We have signs for internal use, for windows and large external signs for external systems.

 Welsh Language Version Available

 

Licensed Premises and CCTV

CCTV is now being stipulated as a requirement for the issue or renewal of a licence.

Many licensees are being exploited in that they are being sold unsuitable equipment. In order to satisfy the police requirements, recorded images must be of an acceptable quality and provide identification to a standard which would be acceptable to use in evidence in a Court of Law.

The problem is that the price asked for a system might not even reflect the quality with some suppliers describing (industry standard) 'medium resolution' as high resolution' and 'high resolution' as 'extra high'. Some companies offer leasing arrangements which are open ended with title to the system never being transferred.

Making the wrong choice could prove costly. If for example, an incident occurred and the images proved to be unacceptable preventing the prosecution of an offender, it might well be considered that the system is not meeting the conditions of the licence and it would have to be up-graded or replaced.