HD Video Surveillance
Going Native
If a system is using HD video streams, then it is essential that
compatible displays are also used to ensure that the higher quality can be viewed.
Alongside ensuring that the specifications of monitors won’t actually reduce the image quality, thought should also be given to the native resolution of the selected displays.
T
oday, in the world of HD video surveillance, the old adage that a video system will only ever achieve the
maximum resolution of the lowest resolution device in the chain still holds true. Take a HD1080p camera and use a standard lens, and you’ll be reducing the final image quality. Take an HD stream and record it at a low resolution, and you’ll lose a lot of image quality. If you are incorporating HD video surveillance - even just a few cameras added to a conventional system - then you will need to ensure that your displays, and their connections, are capable of preserving the quality of the outputted video. One trend that Benchmark has seen is a number of monitors that do not deliver a 16:9 aspect ratio being sold as HD versions. Another is the introduction of the ‘HD Quality’ description.
In the first case, it is possible for different aspect ratio monitors to display HD images, if their resolution is high enough. A common resolution specification nowadays for LCD and LED monitors is 1280 x 1024 pixels. Such a monitor could display a HD720p image. However, letterboxing - a black strip at the top
and bottom of the screen - would occur. Whilst this doesn’t detract from the actual displayed resolution, it is important to understand that the final image size - and visible elements in that image - will subsequently be reduced.
Whilst this former concern is one of understanding how such a choice will affect the final image, the second issue - HD Quality - is less clear. HD Quality is a phrase that means nothing in terms of HD standards. It is sometimes used by manufacturers - predominantly from the Far East, although its use is spreading - to indicate that the resolution is the same as a 4:3 (or other aspect ratio) section taken out of a HD image! Effectively, the monitor will deliver an image with a depth of 1080 or 720 pixels, but not an HD image. There are instances where a monitor gives a 1280 x 1024 pixel image, but can’t be cropped to a 16:9 HD image, so to get around this the term is used. In all cases, it’s nothing short of misleading.
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