CCTV Security Camera News in Da Nang Vietnam

A Guide To Choosing CCTV Security Camera Systems



business-surveillance-system

You can have CCTV professionally installed, and, in some circumstances this may be appropriate. However modern technology has made CCTV products much more affordable and for the average DIY person, easy to fit. With such a large selection of cameras and prices, it is difficult to decide what to select. We have the following guide to help you choose the correct products. We also provide simple illustrations of fitting, from complete systems to fitting in domestic and commercial properties.

‘WIRE-LESS’
A very popular system, wireless transmission is governed by regulations which allow licence-exempt systems to transmit signals up to 100 metres in line of sight. However this can reduce to about 30 metres when used indoors. Basic wireless cameras work on one frequency, this means you cannot use 2 cameras within 100 metres of each other. There are cameras and receivers with 4 selectable channels which allow for multi-camera systems.
We also supply the small covert type of camera with its own built-in transmitter.
See our product range.

A ‘wireless’ camera requires a power source, this is usually obtained by plugging into the mains, making it not strictly ‘wire-less’. Batteries, which have a finite life, are not suitable for permanent installations.
The voltage required is in the range 9-12V DC. A power supply in the loft is often quite easily accessible. Wireless systems are used where running the video cable back to VCR or monitor is not viable.

Wireless cameras can be used for temporary monitoring of stock rooms offices etc.
Miniature wireless cameras, using battery power, can be fitted to model aircraft, trains, boats etc., with the receiver connected to a domestic camcorder, giving a realistic on-board experience.
See our product range.

‘WIRED’¬†
Wired cameras have virtually no interference and can be positioned a long distance from the monitoring/recording equipment. The cameras rarely need their own power supply. Normally one cable takes power and signal back to the recording device. We supply DIY kits where the camera is powered by the base unit, eliminating the need to plug the camera in to a mains outlet.
See our product range

‘TYPES of CAMERAS’
A traditional CCTV camera has an ‘industry style’ look, making it unsuitable for fitting to homes or shops. Top-end cameras are usually specified without a lens and are chosen to give the focal length required and field of view.
There are two common types of CCTV cameras, CMOS and CCD (see Glossary of terms). CMOS based cameras are generally cheaper but do not produce such clear or sharp images. If there is a need to easily identify who or what is being captured and recorded, CCD cameras provide pin-point clarity and are best where clarity is needed.
Integrated cameras and lenses are sealed to prevent moisture damage. This sealing process enables them to be used under water if required. They do not need a heater and their size makes them suitable for fitting to domestic and commercial properties. Because they are permanently sealed it is not possible to adjust these cameras.
Many integrated cameras are fitted with a 3.6mm lens giving a 72deg angle of view which is suitable for most domestic and small commercial properties. We also have cameras with a narrower angle of view allowing the cameras to ‘see’ further – the angle of view for all of our cameras is stated within the bullet point copy.

COLOUR OR MONOCHROME?
The human eye sees and recalls things better if they appear in colour – it’s easier to track down someone with a red top and blue skirt than a grey dressed person that would see in monochrome.
Colour cameras are more expensive than monochrome, but they are also less sensitive making night usage an impractical option unless good lighting is available.
Monochrome cameras can offer Infra Red (IR) sensitivity making their use with covert IR illumination possible. This can be useful where planning permission makes extra lighting impractical or the security requirement is such that intruders should not be alerted to the existence of CCTV surveillance.

OUTDOOR CAMERAS
If a camera is to be sited outside and is not going to be mounted in an enclosure it must be classed as weather resistant. All of our outdoor cameras are fully weatherproof. The cable entry points are sealed and most cameras come with trailing leads that allows the connections to be made inside the building.

DAY/NIGHT CAMERAS 
Very popular in domestic and small commercial CCTV applications, day/night cameras allow great quality, colour recording during daylight hours. When light levels drop below a certain level the camera’s infra red LED’s allow the camera to continue recording good quality footage even in complete darkness. The distance the cameras will see at night is dependent on the strength of the LED’s. See our
The golden rule when deciding which camera to use for a given lighting condition is not to choose one that will only just give a picture.
Try to give the camera approximately 10 times its quoted minimum scene illumination. Most cameras will be able to cope with excess light. The major problem is when they do not have enough light to produce a picture.

RESOLUTION
This is the horizontal resolution in TV lines, i.e., the number of black to white transitions that can be resolved across the image. This is a function of the number of pixels that make up the CCD imaging area and the bandwidth of the camera circuitry. Typical entry level camera resolution is 330 TV lines, with high resolution cameras producing better than 400 lines. Higher resolution costs more!.

How do I display the picture from more than one camera?.
Most CCTV systems deploy several cameras so you need a method to view and record the images. There are various ways this can be achieved; use a video switcher, a quad processor or a multiplexer. Here are the simple benefits of each system.

  • Switchers
    A CCTV switcher is a unit that changes between camera pictures one at a time, the output being viewed on a monitor or passed to the recording device. As switchers can use any VCR to record in true real-time, the pictures can be of a very high quality. The fact that they provide true real-time recording unlike a snapshot from a multiplexer means they provide a superior picture quality. This can sometimes outweigh the disadvantages that switchers can only record one picture at a time.

    Advantages – Simple, low cost, good quality real-time pictures.
    Disadvantage – Can only record one camera at a time.

  • Quad Processors
    Quad processors enable 4 camera pictures to be displayed simultaneously. They are useful where it is necessary to monitor several areas at the same time. As with a switcher, what is seen on the monitor is the picture that is recorded on your VCR.

    Advantages – Simple to use – shows multiple displays which can be recorded.
    Disadvantage – Records only 1 camera at a time real time or 4 at a quarter of the resolution.

  • Multiplexers
    A multiplexer allows simultaneous recording of multiple full-sized camera pictures on to one VCR tape providing a more comprehensive record than with a switcher or a quad processor. Most have variable display options such as quad and picture in a picture allowing flexible surveillance of more than one camera at once.

    When to use a multiplexer
    Generally use when a high degree of surveillance is required and it is necessary to record full resolution pictures from a number of cameras at the same time.

Advantages – Records all camera pictures full size on one tape – gives better monitoring of areas simultaneously – enables large areas to be monitored without losing surveillance due to camera switching time.
Disadvantages – Does not record in real time – Raises the overall cost of the system.