CCTV CAMERA SURVEILLANCE

Cameras

Everfocus Camera 3MP - Stamford Plaza

Cameras play an ever-increasing role in business security - in entrance lobbies, at roller doors, and at entrances to underground car parks. No one likes being watched, but bona fide visitors value the security. Powered-pan tilt cameras can cover large areas, taking in both entrances and exits, and providing a strong deterrent before the fact, and valuable evidence after the fact.

CCTV allows areas such as lifts, entrances exits lobbies and parking areas to be monitored constantly. The systems allow multiple areas to be monitored at once and it is possible to simultaneously monitor customers, shoplifters and staff. CCTV systems can deter and detect crime and is a low cost security option.

IP Infrared Camera - Stamford Plaza

The simplest CCTV system consists of one video camera connected by a cable to a composite video monitor (or television). The more sophisticated systems incorporate a wide variety of cameras, lenses, housings and recording devices and this can also be outputted to an alarm system.

The most commonly used cameras are the CCD or charged coupled devices. Cameras come in black and white and colour. Black and white are less expensive and can be better for low light applications as less light is required to see an image through a black and white camera. Colour cameras are easier to view over extended periods and are essential where data on colour is important.

A critical consideration when choosing a camera is its ability to operate in low light conditions. Cameras now regularly operate to 1.0 lux for colour cameras and 0.1 lux for black and white cameras. Another important consideration is resolution, which is the ability of the camera to reproduce images with as many details as possible. Resolution is expressed in TV lines or TVL and may be 330 to 520 lines for colour and 380 to 580 lines fro black and white. Also signal to noise ratio is important in low light conditions. Cameras can be visible or hidden.

Lenses

The smaller the f-stop number of the lens the faster the lenses and the more light that it allows through. The focal length of a lens determines its viewing angle and lens are sold as fixed focal length or variable focal length.

Cameras can be mounted on moveable platforms and these are called Pan Tilt Cameras. These cameras can be used to view many different locations and usually have zoom lenses. A recent development of the Pan tilt Camera is the integrated speed dome. This is usually a pendant housing and allows a camera to cover many positions – usually with a number of pre-set positions, so that the camera can travel extremely quickly between the various subjects, refocussing as it does so.

Everfocus Monitor - Stamford Plaza Auckland Everfocus Monitor - Stamford Plaza Auckland Everfocus Monitor - Stamford Plaza Auckland

Monitors

As with televisions, monitor size is based on a diagonal measurement of the tube. In New Zealand we use the PAL (program array logic) format. The TFT monitors are superceding the CRT monitors but the CRT monitors still provide a higher quality picture.

Video Transmission

Coaxial cable is the most common form of video transmission and this consists of a solid inner conductor and a woven outer copper braid, which acts as a shield against unwanted signals. RG59 will carry signals up to 220 metres. For distances greater than 220 metres RG6 is used.

This works on the basis of contrast change across a grid over the subject and has greatly improved the integration of video systems

Digital recorders

The digital recorder was first introduced to the industry in the 1990’s. Digital recorders convert the signal to a numerical code of ones and zeros and store it on a hard drive that has been divided into multiple image boxes of a fixed size.

The digital recorder allows continuous CCTV recording and the images are always high quality. Digital recorders also have built in multiplexing and usually record four, eight or sixteen cameras. DVRs come with built-in motion detection and continuously monitor the picture from the cameras. As soon as there is movement they begin recording.

The length the recorder will record for is determined by the compression technology, the number of cameras, the size of the hard drive, whether or not motion-recording control is being used and the picture size and quality. Compression methods include Wavelet, MPEG, and MJPEG. All DVRs have a specified maximum frame rate and the frame rate available per individual camera is determined by dividing the maximum frame rate by the number of cameras. Real Time by definition is 25 frames per second and this is the ideal (benchmark) frame rate for each camera. The frame rate for your installation will depend on the application – if you are monitoring cash or moving traffic the frame rate will need to be much higher than if you are monitoring movements in an office reception area. With the huge increases in storage space that new technology has delivered with larger hard drives the ability to store sufficient data images is no longer a problem.

DVRs have different resolution options and these simply determine the number of pixels in the picture. Higher numbers of pixels means higher clarity of the picture but this also uses more hard disk space.

After an incident has been recorded images can be time and date stamped and moved from the DVR to another storage device such as a USB memory stick (or a CD using CDRW).

Most DVRs are capable of sending an email or text message to a recipient when an event such as detection of movement occurs.

Digital recorders may be Windows based or solid state (Eprom based) and different installers and users have preferred systems. Most people prefer using the windows systems as they are mouse driven but the Eprom based systems have advantages, as they are not affected by the characteristics and anomalies of the operating system.

Panasonic CCTV Equipment

Panasonic manufacture a quality product line that is renowned for its reliability and robustness. We sell and support all Panasonic products. Panasonic entry-level digital colour cameras are excellent value.

The Panasonic Super Dynamic range of cameras captures unsurpassed quality images even in harsh lighting conditions typically experienced when outside sunlight and indoor light sources overlap - such as open doors, lobbies with windows or glass doors and ATMs and outdoors. They cater for the transition from daylight to night and for bright headlights and streetlights.

www.panasonic.co.nz

PACOM Digital Recorders

Pacom or Pacific Communications is a division of Hills Industries Ltd. Operating for over 35 years in Australia, Pacific Communications is an innovative and leading provider of CCTV solutions.

www.pacom.com.au

The Pacom DR16 –PC is an entry level Windows XP Embedded Operating System Recording Resolutions are: 640x480, 640x240, 320x240 and 160x120.

The system has a Display of100 images per second and a recording speed of 1200 images per second at 320 x 240.

The standard hard drive is160 Gb but this can be increased with the use of optional 2 additional hard drives of up to 250GB each. The recorders come with a LAN Network Card and a Composite Output. They also have a VGA output and Remote Access Software. More highly specified recorders are available.

 

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