Useful Information
- ♦ Application
- ♦ Cameras
- ♦ Lenses
- ♦ Light & CCTV
- ♦ Number Plate Recognition
- ♦ Thermal Imaging
- ♦ Housings
- ♦ Digital Images
- ♦ Digital Technology & Recording
- ♦ Video Compression
- ♦ Infrared
- ♦ IR & LED Lighting
- ♦ IP CCTV & Technology
- ♦ Monitors
- ♦ Motion Detection
- ♦ Multiplexers
- ♦ PIR Movement Sensor
- ♦ Remote Positioning Devices
- ♦ Video Motion Detection
- ♦ Police and Standards
- ♦ Multiple Screen Display
- ♦ Signal Noise Ratio
- ♦ Survellance Vechicle
- ♦ Three-dimensional (3D) design in CCTV & Security
- ♦ Transmission of Video Signals by Cable
- ♦ Transmission of Video Signals by Remote Methods
- ♦ Transmission of Video Signals by Fibre Optics
- ♦ Video Analysis
- ♦ Wireless CCTV
Multiple Screen Display
Any system that combines more than one video signal is technically a multiplexer. These days it is customary to refer to multiplexers as equipment that can simultaneously combine eight or more signals, otherwise they are known as screen splitters or quad splitters.
There will be many occasions when it will be advantageous to display more than one camera on the monitor at once.
One example is if an incident occurs but it is not certain just where it originated. With a simple switching device, it would be a tedious business to review all the cameras recorded in sequence. In addition, as stated previously, essential information may be lost.
However, if all the cameras were recorded simultaneously and could be displayed simultaneously then reviewing and finding the sequence of events would be very much easier. In addition, virtually no information would be lost and the relevant scenes can then be analysed with full screen pictures.
The essential benefit therefore of recording in the various multiple screen formats is that no information is lost due to dwells in switching.
Analogue and Digital Displays
The picture received directly from a camera and displayed on a monitor is an analogue representation of the scene. The picture information has been converted directly to a video signal and reconverted to the same scene on the monitor. The clarity of the picture is dependent on the quality of the camera, the lens, the transmission system and the monitor.
To display or record more than one picture at a time it is necessary on most systems to convert the analogue signal to a digital form. This is known as analogue to digital conversion. After processing, the signal then has to be converted back to analogue form to be displayed on a monitor.
This process introduces the possibility of degradation to the original picture. Definition can be lost through the complicated conversion processes and noise can be added to the signal. Also, the final quality is dependent on the resolution in terms of the number of pixels comprising the digital information.