The Sony Guide to CCTV Issue this is not a rehearsal.
Contents 1 Introduction 2 Case Studies 6 What is Closed Circuit Television? 7 When and Where should it be used? 8 Light 11 Choosing a Camera 15 Selecting the Correct Lens 18 Which Monitor? 20 Transmission of Video Signals 23 Video Switching and Multiplexing 25 CCTV Systems Control 26 Recording 28 Sony CCTV Products 32 Basic CCTV Terminology
Introduction In recent years... there has been no shortage of innovations in the CCTV industry with manufacturers competing to better meet the needs of crime prevention. Most visibly, more surveillance cameras have appeared in more public areas than ever before, proving their effectiveness and generating interest in maximising the benefits of operating a surveillance system.
case study Sony gives Newham a clearer picture Newham District Council has the largest local authority CCTV control room in the country, monitoring over 200 cameras in the heart of London’s East End. Recently, it has installed additional Sony Trinitron colour video monitors, bringing the total in the system to 73 screens.
case study Underground Security Expanded The latest phase in London Underground’s multi-million pound refurbishment programme includes the installation of 60 Sony CCTV cameras at three of South London's busiest central stations: Brixton, Pimlico and Vauxhall.
case study Daewoo savings with Sony PMS In the face of rising manned guarding costs, Daewoo Cars has installed a new remote surveillance alternative – a monitoring codec from Sony. Daewoo was spending over £1 million a year on manned guarding services for its 25 forecourt and showroom sites until a remote video monitoring service introduced a complete design, commissioning and monitoring package based around remote CCTV surveillance.
case study Farsight Chooses the HSR-1P One of the UK’s largest remote video monitoring companies has chosen the Sony HSR-1P to replace its existing complement of time-lapse video recorders and multiplexers. On a weekly basis Farsight (UK) Ltd, based in Peterborough, makes and receives in excess of 20,000 video patrols/alarms from its diverse mix of clients situated throughout the UK.
What is Closed Circuit Television? Closed Circuit Television (CCTV) is a television system which operates on a ‘closed loop’ basis. Unlike broadcast television, which is available to anyone with a suitable receiver, CCTV pictures are only available to those directly connected to the loop. Colour Video Monitor Video Out (Coaxial cable) DC12 V DC12 V power supply AC outlet CCTV was first used in the 1950s and has since become an essential element in any professional security system.
When and where should it be used? Security and surveillance are the most accepted applications for CCTV systems. With the use of CCTV, managers and supervisors can control risks and minimise costs efficiently and with the minimum of disruption.
Light The human eye and the camera lens operate on completely different lines. Although the human eye adjusts automatically to various light conditions, the camera is inherently less flexible. In a CCTV system, lighting has to be ‘designed in’ from the beginning if the best results are to be obtained. The type of lighting used, and the correct positioning, are vital to maximum security. Everyday ‘white light’ is actually a mixture of colours of different frequencies.
Light LUX* DESCRIPTION 50,000 British summer sunshine 5,000 Overcast sky 500 Well lit office 300 Minimum for easy reading 50 Passageway/outside working area 15 Good main road lighting 10 Sunset 5 Typical side road lighting 2 Minimum security risk lighting 1 Twilight 0.3 Clear full moon 0.1 Typical moonlight/cloudy sky 0.001 Typical starlight 0.0001 Poor starlight *Metric unit of measurement of light.
Light Backlight Compensation It is also important to consider whether there are bright spots in the picture such as car headlights which can make identification of the vehicle registration or model impossible. This can also be a major problem where it is necessary to identify persons who are moving from bright daylight into artificial light. Very often this will result in the subject becoming an unidentifiable silhouette. The problem is exacerbated where bright spots in the images cause vertical smearing.
Choosing a Camera The camera is the ‘eye’ of a CCTV system and at its core lies CCD (charge coupled device) technology. The CCD is comprised of about 500,000 light sensitive cells called picture elements (pixels) which convert the light falling onto its surface into an electrical signal. The performance of the camera, and ultimately the surveillance system, is more dependent upon the quality of the CCD than any of the other camera components.
Choosing a Camera Sensitivity Colour cameras generally perform less well in low light than monochrome cameras, all other things being equal. Sensitivity is usually measured by reference to the lux level at which a camera can produce an image (see page 9). The lux valuation, although usually referred to as a metric unit of measurement of light, is very often applied subjectively to the ability of a camera to produce images.
Choosing a Camera TURNER TO INSERT IMAGE (GLASS YOU SCANNED!). ADJUST PIC BOX IF NEC. Camera Resolution The higher the resolution the sharper the picture. The best resolution available at present for CCD cameras is approaching 750 horizontal lines (TV lines) (3-CCD, DXC-950P) and 500 vertical lines. Resolution is not necessarily the key decision point.
Choosing a Camera developed a range of Hyper HAD CCD Ineffective area solutions, the most popular of which include hybrid cameras that operate in colour when lighting is adequate, switching to monochrome as darkness falls. Some cameras operate in low light by reducing the number of frames Transfer register Hole accumulated layer captured to produce a brighter picture although Exwave HAD CCD this causes problems when there is movement within the image.
Selecting the Correct Lens The quality of the lens is vital in determining the quality of the final image. The basic optical characteristics of a lens are the focal length (in zoom lenses the focal length range) or angle of coverage, and the aperture range. We’ll look at these two characteristics together with a third important characteristic, the format.
Selecting the Correct Lens Aperture range The aperture is the clear opening in the centre of the lens that allows light to pass to the pick-up device. The aperture size is described in relation to the focal length (F). Thus the aperture is specified by an F number. If the lens has a focal length of 50mm and if the diameter of the clear opening of the lens is 25mm, then the lens is said to have an aperture of F:2 (50mm divided by 25mm = 2).
Selecting the Correct Lens Another characteristic of lenses is the ‘depth of field’ (see illustration). If a lens is focused on an object there will be a certain area of sharp focus in front of and behind the object. The depth of this area of sharp focus is controlled by three factors: the focal length of the lens, the distance from the lens to the object and the F stop. Lens Format The lens format relates to the camera format, 1/3 inch, 1/2 inch, 2/3 inch. There are two lens mounting systems.
Which Monitor? A control room operator may be required to view images on a bank of monitors for prolonged periods. As the effectiveness of the surveillance system is crucially dependent upon the degree to which the operator can remain alert and avoid fatigue, correct monitor selection is vital. The monitor converts the video signal generated by the camera back into a visual image. It consists of a cathode ray tube (CRT) and a number of signal processing circuits.
Which Monitor? Monitor Size Typical Viewing Distance 9˝ 12˝ 17˝ 21˝ 5´ 10´ 15´ CCTV monitors may be free standing, suspended from a wall or ceiling, or rack mounted. Wall and ceiling mounts allow the monitor to be rotated and tilted for viewing from different angles. Monitor costs Why does a 17-inch black and white CCTV monitor cost more than the equivalent black and white TV? The answer is that the CCTV monitor has specialist features and characteristics.
Transmission of Video Signals A CCTV signal contains a wide range of frequencies from around 30 hertz to around 10 Megahertz. As a result special circuits are required to cope with the wide band-width if signal quality is to be maintained during transmission. Because signals from CCTV cameras often have to travel long distances to reach the control centre, the choice of transmission medium depends upon the particular installation and its requirements. Coaxial Cable P.V.C.
Transmission of Video Signals Twisted Pair An alternative to the use of coaxial cable is the ‘twisted pair cable’. A twisted pair cable is known as a ‘balanced’ cable and can be similar to telephone wires. Most of the same considerations apply to twisted pair as apply to the coaxial but there are some expectations.
Transmission of Video Signals Personal Computer Local Remote RS232C ISDN PMS-400P/500P PMS-400P/500P These devices facilitate a flexible range of applications and are increasingly being manufactured to international standards H.320 & H.261 (ITU-T recommendation). 22 The Sony Guide to CCTV .
Video Switching and Multiplexing If a system consists of a single camera and monitor, then a switching device will not be required. It would not, of course, be practical or desirable in a multi-camera system to have a monitor for every camera. In these cases, a switcher will enable the video signal from several cameras to be viewed on just one monitor.
Video Switching and Multiplexing Multiplexers Multiplexers are a more functionally useful way of handling a multi-camera system. Like a switcher, several cameras (usually up to 16) can be connected to the multiplexer. A single field or frame from each camera is successively output via the multiplexer onto a video recording. Playback would take place again via the multiplexer which would decode the recording to the monitor.
CCTV Systems Control While the majority of cameras are installed in a fixed position, in order for the operator to be able to follow an incident it can be very useful to have the facility to pan, tilt and zoom the camera. This is achieved by the use of a mechanical pan and tilt head on which the camera is mounted and a zoom lens which are controlled remotely by telemetry signals.
Recording While a proportion of surveillance systems are continuously monitored, these are in the minority. The majority of systems are not actively monitored and, even when they are, in most cases, the images are still recorded. The underlying principle to be considered in relation to the recording of images is that they may ultimately be required as evidence in criminal proceedings.
Recording DV Tape Drive DV Signal Transfer Hard Disk Drive HSR-1P Recording Process archived to Digital Video (DV) tape. Resolution modes of up to 500 TV lines can be accessed which are simply not possible on conventional analogue VCRs. The evidential value of digital recording has been considered by a distinguished committee of Law Lords who have concluded that the same procedural requirements which apply to analogue recording are also applicable to this more recent technology.
Sony CCTV Products Colour CCD Cameras SSC-DC50/54/58AP ExwaveHAD, half-inch, 470 TVL, 0.8Lux SSC-DC10/14/18P Third-inch, 470 TVL, 1.7Lux SSC-C104/8P Third-inch, 330 TVL, 1.2Lux SSC-CX34P Third-inch, 470 TVL, c/w 12x motorised zoom lens Monochrome CCD Cameras SSC-M370CE Half-inch, 570 TVL, 0.3Lux SPT-M304/308CE Third inch, 570 TVL, 0.25Lux SPT-M320/324/328CE ExwaveHAD, third-inch, 570 TVL SPT-M122/4/8CE Third-inch, 380 TVL, 0.1Lux 28 The Sony Guide to CCTV .
Sony CCTV Products Colour Video Monitors SSM-14N5E Trinitron,14-inch, 600 TVL, Y/C and audio SSM-20N5E Trinitron, 20-inch, 600 TVL, Y/C and audio SSM-9040P Trinitron, 9-inch, 250 TVL Monochrome Video Monitors SSM-930CE 9-inch, 750 TVL, DC clamp SSM-125CE 12-inch, 750 TVL, DC clamp and dual inputs SSM-175CE 17-inch, 850 TVL, DC clamp and dual inputs SSM-Q177CE 17-inch, 850 TVL, built in quad processor and sequential switcher For more information contact the Sony Business Information Centre: 01
Sony CCTV Products Time-Lapse Video Recorders SVT-124P 24-hour compact VHS SVT-1000P 72-hour VHS, RS-232C option SVT-L230P 72/96 hour VHS, ‘RealAction’, RS232C option SVT-5050P 960-hour VHS, RS232C option SVT-S3050P 168-hour Super-VHS, RS-232C option SVT-RS1A RS-232C Interface Board SVT-RM10 Wired Remote Control TPK-Series 10,000 hour service kits for all VCRs ISDN Transmission PMS-500P Transmitter/receiver codec PMS-400P Transmitter codec 30 The Sony Guide to CCTV .
Sony CCTV Products Digital Surveillance Recorder HSR-1P DV-based, up to 6,480,000 image storage capacity, built-in 16 channel multiplexer Multiplexers YS-SX210CE Mono, simplex, 10 channel YS-SX310P Colour, simplex, 10 channel YS-DX216CE Mono, duplex, 16 channel YS-DX316P Colour, duplex, 16 channel Quad YS-Q440P Colour, 4 channel For more information contact the Sony Business Information Centre: 01932 816340 31
Basic CCTV Terminology APC Adaptive Picture Control. VCR function which automatically detects the condition of the recording head and the video tape and then sets the optimum record head current to prevent over-modulation. AGC Automatic Gain control. Usually a switchable circuit that allows the camera to provide a ‘useable’ picture during low light levels. You can generally tell when the circuit is operating because the picture appears to be ‘grainy’.
Basic CCTV Terminology DEPTH OF FIELD The distance between the furthest and nearest points at the same level of definition within a certain view. HAD SENSOR An improved type of semi-conductor sensor which gives cameras a better smear and noise performance. DIGITAL VIDEO A video storage media using 5:1 compression method. HDR Hard Disk Recorder. A device which captures images to hard disk.
Basic CCTV Terminology MECHANICAL FOCUS Focusing of a camera lens or pick-up device by mechanical means. MONOCHROME Black and white picture comprising of a number of levels of grey scales. MULTIPLEX Method of transmitting or recording many video signals at the same time. ND Neutral Density. Filter which is positioned on the rear of the lens, enabling the camera to operate in difficult lighting conditions, by widening its operating parameters.
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The Sony Guide to CCTV Issue 3 Written by: Brian Kelly Edited by: Carey Green Designed by: Peter Courtley Sony Publications Manager: Jackie Cook
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